Electrical and Electronics Engineering publications abstract of: 10-2017 sorted by title, page: 17

» Portable and Reconfigurable Wrist Robot Improves Hand Function for Post-Stroke Subjects
Abstract:
Rehabilitation robots have become increasingly popular for stroke rehabilitation. However, the high cost of robots hampers their implementation on a large scale. This paper implements the concept of a modular and reconfigurable robot, reducing its cost and size by adopting different therapeutic end effectors for different training movements using a single robot. The challenge is to increase the robot’s portability and identify appropriate kinds of modular tools and configurations. Because literature on the effectiveness of this kind of rehabilitation robot is still scarce, this paper presents the design of a portable and reconfigurable rehabilitation robot and describes its use with a group of post-stroke patients for wrist and forearm training. Seven stroke subjects received training using a reconfigurable robot for 30 sessions, lasting 30 min per session. Post-training, statistical analysis showed significant improvement of 3.29 points (16.20%, p = 0.027) on the Fugl-Meyer assessment scale for forearm and wrist components. Significant improvement of active range of motion was detected in both pronation-supination (75.59%, p = 0.018) and wrist flexion-extension (56.12%, p = 0.018) after the training. These preliminary results demonstrate that the developed reconfigurable robot could improve subjects’ wrist and forearm movement.
Autors: Kang Xiang Khor;Patrick Jun Hua Chin;Che Fai Yeong;Eileen Lee Ming Su;Aqilah Leela T. Narayanan;Hisyam Abdul Rahman;Qamer Iqbal Khan;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Oct 2017, volume: 25, issue:10, pages: 1864 - 1873
Publisher: IEEE
 
» Position and Orientation Insensitive Wireless Power Transmission for EnerCage-Homecage System
Abstract:
We have developed a new headstage architecture as part of a smart experimental arena, known as the EnerCage-HC2 system, which automatically delivers stimulation and collects behavioral data over extended periods with minimal small animal subject handling or personnel intervention in a standard rodent homecage. Equipped with a four-coil inductive link, the EnerCage-HC2 system wirelessly powers the receiver (Rx) headstage, irrespective of the subject's location or head orientation, eliminating the need for tethering or carrying bulky batteries. On the transmitter (Tx) side, a driver coil, five high-quality (Q) factor segmented resonators at different heights and orientations, and a closed-loop Tx power controller create a homogeneous electromagnetic (EM) field within the homecage 3-D space, and compensate for drops in power transfer efficiency (PTE) due to Rx misalignments. The headstage is equipped with four small slanted resonators, each covering a range of head orientations with respect to the Tx resonators, which direct the EM field toward the load coil at the bottom of the headstage. Moreover, data links based on Wi-Fi, UART, and Bluetooth low energy are utilized to enables remote communication and control of the Rx. The PTE varies within 23.6%–33.3% and 6.7%–10.1% at headstage heights of 8 and 20 cm, respectively, while continuously delivering >40 mW to the Rx electronics even at 90° rotation. As a proof of EnerCage-HC2 functionality in vivo, a previously documented on-demand electrical stimulation of the globus pallidus, eliciting consistent head rotation, is demonstrated in three freely behaving rats.
Autors: Yaoyao Jia;S. Abdollah Mirbozorgi;Zheyuan Wang;Chia-Chun Hsu;Teresa E. Madsen;Donald Rainnie;Maysam Ghovanloo;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Oct 2017, volume: 64, issue:10, pages: 2439 - 2449
Publisher: IEEE
 
» Position-Aided Large-Scale MIMO Channel Estimation for High-Speed Railway Communication Systems
Abstract:
We consider channel estimation for high-speed railway communication systems, where both the transmitter and the receiver are equipped with large-scale antenna arrays. It is known that the throughput of conventional training schemes monotonically decreases with the mobility. Assuming that the moving terminal employs a large linear antenna array, this paper proposes a position-aided channel estimation scheme whereby only a portion of the transmit antennas send pilot symbols and the full channel matrix can be well estimated by using these pilots together with the antenna position information based on the joint spatial-temporal correlation. The relationship between mobility and throughput/DoF is established. Furthermore, the optimal selections of transmit power and time interval partition between the training and data phases as well as the antenna size are presented accordingly. Both analytical and simulation results show that the system throughput with the position-aided channel estimator does not deteriorate appreciably as the mobility increases, which is sharply in contrast with the conventional one.
Autors: Tao Li;Xiaodong Wang;Pingyi Fan;Taneli Riihonen;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 8964 - 8978
Publisher: IEEE
 
» Positioning in MIMO Radars Based on Constrained Least Squares Estimation
Abstract:
This letter presents a novel solution for the problem of moving target localization in multiple-input multiple-output radar systems. The localization problem is formulated, based on least squares criterion, as a non-convex optimization problem and solved by semidefinite relaxation method. Then, an improvement technique, refining the initial solution by estimating the error terms, is proposed. Numerical simulations demonstrate that the proposed method achieves a significant performance improvement over the state-of-the-art methods. Specifically, the proposed method is shown to be more robust to the noise level compared with the existing algorithms.
Autors: Rouhollah Amiri;Fereidoon Behnia;Mohammad Amin Maleki Sadr;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2222 - 2225
Publisher: IEEE
 
» Postdisaster User Location Maneuvering Method for Improving the QoE Guaranteed Service Time in Energy Harvesting Small Cell Networks
Abstract:
The concept of energy harvesting small cell networks (EH-SCNs) has attracted a great deal of attention due to their potential to meet the exponential growth of mobile data traffic with low capital expenditure and operating expenditure. In addition, they are expected to work as a postdisaster wireless access network since exploiting green energy sources to power small cell base stations can overcome the power disruption caused by disasters. However, since the amount of harvested power is not enough for the stable network operation, the networks need to equipped with energy-efficient networking techniques. Additionally, in order to share the accurate postdisaster information, the networks should satisfy a certain quality of experience (QoE) of users in disaster areas. To deal with these challenges, we propose a user location maneuvering method, which advisory controls user's movement to improve the service time of EH-SCNs while guaranteeing a certain QoE level. We also propose an algorithm based on particle swarm optimization, which is configured with appropriate settings to find the best location of users efficiently. Extensive computer simulations show that the proposed maneuvering method can improve the QoE guaranteed service ratio, compared with the existing network operation approaches.
Autors: Katsuya Suto;Hiroki Nishiyama;Nei Kato;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 9410 - 9420
Publisher: IEEE
 
» Potentials of Active and Passive Geospatial Crowdsourcing in Complementing Sentinel Data and Supporting Copernicus Service Portfolio
Abstract:
The recent trend toward open Earth observation (EO) data has revived a general interest in satellite-based monitoring and mapping of the Earth surface. The open policy now applied to LANDSAT data, and the starting of Sentinel operations, whose data are freely distributed even for commercial purposes, tore down a financial barrier to wider use of EO data in business activities, especially those with a narrow financial margin. Notwithstanding the flood of open data, some aspects of the Earth surface still escape satisfactory monitoring from space, especially in complex, anthropic areas. Due to insufficient spatial resolution, lack of visibility, or unsuitable revisit times, important pieces of information may not emerge from spaceborne data. In situ sensing can represent a vital source of integrative information to fill the aforementioned gaps and build a more complete and accurate picture of the situation and trends in the observed area. The contribution of in situ sensing was envisaged quite early in the Earth observation history, but for a long time it remained limited to tailored sensors displaced in strategic locations. With the increasing circulation of smartphones, a new opportunity has recently opened for a different paradigm of in situ sensing, offering a huge mass of additional data by tapping on data generated by mobile devices. Even if such data may be less specialized and less usable for various reasons, the sheer size of the data flow ensures that statistical analysis will pick possible useful clues. The increasing availability of mobile connections has indeed revived the concept of “crowdsourcing,” i.e., entrusting a pool of actors with problem solution or information collection tasks. In our scenario, individuals carrying mobile devices can become “citizen sensors” on a voluntary basis by contributing data through their connected terminals. Ev- n considering the typical issues of crowdsourced data, like quality and reliability, the balance remains definitely positive. This paper provides an overview of the theme and discusses how it relates to an important, coordinated EO initiative like Copernicus. It finally presents a specific example realized in the framework of a recent research project under the Copernicus aegis.
Autors: Fabio Dell’Acqua;Daniele De Vecchi;
Appeared in: Proceedings of the IEEE
Publication date: Oct 2017, volume: 105, issue:10, pages: 1913 - 1925
Publisher: IEEE
 
» Power Budget Improvement in Passive Optical Networks Using PAM4 Hierarchical Modulation
Abstract:
Hierarchical PAM4 modulation in passive optical network downstream channels is experimentally demonstrated as a way to redistribute power margin between users with different path losses due to unequal fiber distribution and split losses. Using hierarchical PAM4 modulation the most-significant bit (MSB) and less-significant bit (LSB) can be assigned to two different optical network units (ONU) groups, whose receiver sensitivity can be optimized to increase the power budget of the ONUs with higher path losses, effectively redistributing power margin of the ONUs with lower losses. A single-threshold receiver is sufficient for the MSB ONU type and a dual-threshold receiver coupled with an and logic gate for the LSB ONU type, both of which are simpler than a full PAM4 receiver with three thresholds. Sensitivity improvement in a 25 Gb/s system is achieved using unequal signal level spacing and separate detection of the binary tributary streams of the PAM4 channel. Power budget increase of up to 3.5 dB is reported with respect to a standard PAM4 transmission. Higher chromatic dispersion tolerance is also measured for the higher sensitivity ONU group, enabling transmission over up to 40 km of single-mode fiber for the MSB ONUs with no chromatic dispersion compensation.
Autors: Marco Dalla Santa;Cleitus Antony;Giuseppe Talli;Paul D. Townsend;
Appeared in: IEEE Photonics Technology Letters
Publication date: Oct 2017, volume: 29, issue:20, pages: 1747 - 1750
Publisher: IEEE
 
» Power Efficiency and Delay Tradeoff of 10GBase-T Energy Efficient Ethernet Protocol
Abstract:
In this paper, we study the power efficiency and delay performance of the burst mode transmission (BTR) strategy for the IEEE 802.3az energy efficient Ethernet (EEE) protocol. In the BTR strategy, the Ethernet interface goes to sleep once its transmission buffer becomes empty and wakes up as soon as the first arrival has waited for time or the -th frame arrives at the interface. Based on the number of arrivals during the vacation time, a new approach is proposed to analyze the M/G/1 queue with vacation times that are governed by the arrival process and the and parameters of BTR strategy. Our key idea is to establish the connection between the vacation time and the arrival process to account for their dependency. We first derive the distribution of the number of arrivals during a vacation time based on an event tree of the BTR strategy, from which, we obtain the mean vacation time and the power efficiency. Next, from the condition on the number of arrivals at the end of a vacation period, we derive a generalized P-K formula of the mean delay for EEE systems, and prove that the classical P-K formula of the vacation model is only a special case when the vacation time is independent of the arrival process. Our analysis demonstrates that the policy and policy of the BTR strategy are compensating each other. The policy ensures the frame delay is bounded when the traffic load is light, while the policy ensures the queue length at the end of vacation times is bounded when the traffic load is heavy. These results, in turn, provide the rules to select appropriate and . Our analytical results are confirmed by simulations.
Autors: Xiaodan Pan;Tong Ye;Tony T. Lee;Weisheng Hu;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Oct 2017, volume: 25, issue:5, pages: 2773 - 2787
Publisher: IEEE
 
» Power Management Approach to Minimize Battery Capacity in Wind Energy Conversion Systems
Abstract:
In a wind-battery hybrid power system, minimal battery capacity is a crucial requirement to achieve economic operation. In this paper, an optimal power control strategy based on a first-order low-pass filter is proposed to minimize the battery capacity by adjusting the filter smoothing time constant. We demonstrate the mathematical relationship between the filter smoothing time constant and the fluctuation mitigation requirement during one sampling time, so the optimal filter smoothing time constant can be easily computed to minimize the battery capacity. Moreover, an online short-term power control is also considered to maintain the battery state of charge within a safe range and to regulate the battery power below its rating. The proposed power management approach is simple and easy to implement. In order to verify the effective features of the proposed power management approach, a case study is carried out along with some experimental verification.
Autors: Cong-Long Nguyen;Hong-Hee Lee;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4843 - 4854
Publisher: IEEE
 
» Power Modulator for High-Yield Production of Plasma-Activated Water
Abstract:
Water can be activated by applying plasma to water, for instance, by creating plasma inside (bubbles in) the water, or along a water surface. Plasma-activated water (PAW) typically contains hydrogen peroxide, nitrates, nitrites, and peroxynitrite, and typically has a pH ranging from 2 to 4. The components of PAW and the low pH have proven synergistic antimicrobial effects against bacteria, biofilms, yeasts, and other microorganisms. This paper describes a power modulator and a plasma reactor system for high-yield production of PAW at high production rate. A compact and solid-state dual resonant system has been realized and successfully demonstrated for industrial PAW production. The system generates up to 80-kV (theoretical 120 kV is possible) dual-resonant high-voltage pulses with an oscillation frequency up to 2 MHz, pulse repetition rate > 20 kHz, and an average power of 800-W continuous. In addition to the power modulator, the PAW production system consists of a transient arc plasma reactor and a loop system. Depending on the application, the system is able to activate 10–100 L/h. The disinfecting properties of the PAW production system have been verified by experiments on the reduction of Staphylococcus Epidermidis. Directly after its production, the log reduction of S. Epidermidis can be as high as >8 log. During a period of at least 40 min after its production, the PAW has “mild” disinfecting properties, being able to deactivate S. Epidermidis by 3–4.1 log.
Autors: A. J. M. Pemen;P. P. van Ooij;F. J. C. M. Beckers;W. F. L. M. Hoeben;A. M. C. B. Koonen-Reemst;T. Huiskamp;P. H. M. Leenders;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Oct 2017, volume: 45, issue:10, pages: 2725 - 2733
Publisher: IEEE
 
» Practical LTE and WiFi Coexistence Techniques Beyond LBT
Abstract:
Coexistence with WiFi is the key issue for unlicensed band LTE. The main coexistence mechanism is listen-before-talk, whereby radio frequency energy is sensed over a short period and compared to a threshold. Given the default energy thresholds, the energy sensing range is much less than the cell range. Either technology can experience a collision due to transmissions being below energy detection threshold. Currently, WiFi is agnostic to unlicensed band LTE. To improve coexistence, a relay-based communications channel is proposed whereby LTE announces its presence. Legacy WiFi APs may be programmed to interpret and respond by firmware upgrade . Higher performance for both networks is demonstrated via more effective radio frequency channel selection and adaptive energy detection thresholding.
Autors: Jonathan Ling;David Lopez-Perez;Mohammad R. Khawer;
Appeared in: IEEE Communications Magazine
Publication date: Oct 2017, volume: 55, issue:10, pages: 127 - 133
Publisher: IEEE
 
» Practical Network-Wide Packet Behavior Identification by AP Classifier
Abstract:
Identifying the network-wide forwarding behaviors of a packet is essential for many network management applications, including rule verification, policy enforcement, attack detection, traffic engineering, and fault localization. Current tools that can perform packet behavior identification either incur large time and memory costs or do not support real-time updates. In this paper, we present AP Classifier, a control plane tool for packet behavior identification. AP Classifier is developed based on the concept of atomic predicates, which can be used to characterize the forwarding behaviors of packets. Experiments using the data plane network state of two real networks show that the processing speed of AP Classifier is faster than existing tools by at least an order of magnitude. Furthermore, AP Classifier uses very small memory and is able to support real-time updates.
Autors: Huazhe Wang;Chen Qian;Ye Yu;Hongkun Yang;Simon S. Lam;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Oct 2017, volume: 25, issue:5, pages: 2886 - 2899
Publisher: IEEE
 
» Practical Perfect Absorption in Monolayer Graphene by Prism Coupling
Abstract:
We propose a practical perfect absorber comprising three dielectric layers for prism coupling with monolayer graphene embedded in the middle layer. Since the loss rate can be controlled by the graphene position within the middle layer, the limitation on the material index choice is greatly relieved, overcoming the problem of the previously studied similar structure. It is shown that F2 glass-silica-quartz structure enables perfect absorption if the silica layer thickness and the graphene position are properly chosen. The proposed structure can adopt a thin layer of any absorbing material for perfect absorption owing to the adaptive loss rate feature.
Autors: Sangjun Lee;Sangin Kim;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 10
Publisher: IEEE
 
» Practical Power-Balanced Non-Orthogonal Multiple Access
Abstract:
This paper is a theoretical-plus-experimental investigation of practical 5G strategies for power-balanced non-orthogonal multiple access (NOMA). By allowing multiple users to share the same time and frequency, NOMA can scale up the number of served users and increase spectral efficiency compared with existing OMA. Conventional NOMA schemes with successive interference cancellation (SIC) do not work well when users with comparable received powers transmit together. To allow power-balanced NOMA (more exactly, near power-balanced NOMA), this paper investigates a new NOMA architecture, named network-coded multiple access (NCMA). A distinguishing feature of NCMA is the joint use of physical-layer network coding (PNC) and multiuser decoding to boost NOMA throughputs. We first show that a simple NCMA architecture in which all users use the same modulation, referred to as rate-homogeneous NCMA, can achieve substantial throughput improvement over SIC-based NOMA under near power-balanced scenarios. Then, we put forth a new NCMA architecture, referred to as rate-diverse NCMA, in which different users may adopt different modulations commensurate with their relative SNRs. A challenge for rate-diverse NCMA is the design of a channel-coded PNC system. This paper is the first attempt to design channel-coded rate-diverse PNC. Experimental results on our software-defined radio prototype show that the throughput of rate-diverse NCMA can outperform the state-of-the-art rate-homogeneous NCMA by 80%. Overall, rate-diverse NCMA is a practical solution for near power-balanced NOMA.
Autors: Haoyuan Pan;Lu Lu;Soung Chang Liew;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Oct 2017, volume: 35, issue:10, pages: 2312 - 2327
Publisher: IEEE
 
» Pre-Charged Local Bit-Line Sharing SRAM Architecture for Near-Threshold Operation
Abstract:
In this paper, a pre-charged local bit-line sharing (PCLBS) static random access memory (SRAM) for near-threshold operation is proposed. In previous local bit-line sharing SRAMs, such as average-8T and full-swing local bit-line (FSLB) SRAMs, multiple bit-cells share a local bit-line pair with a small capacitance for high read stability. However, the average-8T SRAM has a considerably large delay because the full development of the local bit-line cannot be achieved. On the other hand, the FSLB SRAM reduces the delay but requires a timing constraint of control signals to achieve sufficient read sensing margin. The proposed PCLBS SRAM achieves high read speed by fully developing local bit-line pair without a timing constraint. Furthermore, the proposed PCLBS SRAM enhances the read stability and the write ability by, respectively, applying a pre-charged local bit-line scheme and transmission gates in write paths. Based on a 22-nm FinFET technology, the FSLB and proposed PCLBS SRAM have the minimum operating voltages of 0.44 and 0.4 V, respectively, while achieving the target read stability and write ability yields. Compared with the FSLB SRAM, the proposed PCLBS SRAM consumes 21% less energy at each minimum operating voltage and has 57% smaller read delay at the operating voltage of 0.4 V.
Autors: Tae Woo Oh;Hanwool Jeong;Juhyun Park;Seong-Ook Jung;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Oct 2017, volume: 64, issue:10, pages: 2737 - 2747
Publisher: IEEE
 
» Pre-Equalized Faster-Than-Nyquist Transmission
Abstract:
Faster-than-Nyquist (FTN) transmission applies non-orthogonal linear modulation to increase spectral efficiency compared with the well-known orthogonal transmission at Nyquist rate. This comes at a price of inter-symbol interference (ISI), which usually is equalized through receiver processing. In this paper, we investigate the alternative approach of pre-equalization at the transmitter. First, we consider Tomlinson–Harashima precoding (THP) for FTN and propose two novel soft demapping algorithms to generate the soft-input for the error-correction decoder. The developed demappers effectively compensate the modulo-loss associated with conventional THP transmission. Second, we propose a linear pre-filtering strategy to pre-equalize the ISI induced by FTN. We show that the linear pre-equalization approach is equivalent to an orthogonal transmission with a modified pulse shape. It thus yields the optimal error-rate performance while affording higher spectral efficiency. We validate our proposed precoding algorithms through computer simulations of a coded coherent optical communication system as a practical application example for FTN.
Autors: Mrinmoy Jana;Ahmed Medra;Lutz Lampe;Jeebak Mitra;
Appeared in: IEEE Transactions on Communications
Publication date: Oct 2017, volume: 65, issue:10, pages: 4406 - 4418
Publisher: IEEE
 
» Pre-Processing Censored Survival Data Using Inverse Covariance Matrix Based Calibration
Abstract:
Censoring is a common phenomenon that arises in many longitudinal studies where an event of interest could not be recorded within the given time frame. Censoring causes missing time-to-event labels, and this effect is compounded when dealing with datasets which have high amounts of censored instances. In addition, dependent censoring in the data, where censoring is dependent on the covariates in the data leads to bias in standard survival estimators. This motivates us to develop an approach for pre-processing censored data which calibrates the right censored (RC) times in an attempt to reduce the bias in the survival estimators. This calibration is done using an imputation method which estimates the sparse inverse covariance matrix over the dataset in an iterative convergence framework. During estimation, we apply row and column-based regularization to account for both row and column-wise correlations between different instances while imputing them. This is followed by comparing these imputed censored times with the original RC times to obtain the final calibrated RC times. These calibrated RC times can now be used in the survival dataset in place of the original RC times for more effective prediction. One of the major benefits of our calibration approach is that it is a pre-processing method for censored data which can be used in conjunction with any survival prediction algorithm and improve its performance. We evaluate the goodness of our approach using a wide array of survival prediction algorithms which are applied over crowdfunding data, electronic health records (EHRs), and synthetic censored datasets. Experimental results indicate that our calibration method improves the AUC values of survival prediction algorithms, compared to applying them directly on the original survival data.
Autors: Bhanukiran Vinzamuri;Yan Li;Chandan K. Reddy;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Oct 2017, volume: 29, issue:10, pages: 2111 - 2124
Publisher: IEEE
 
» Precision of Ku-Band Reflected Signals of Opportunity Altimetry
Abstract:
This letter provides a proof-of-concept experiment and validation of an error model for bistatic altimetry using signals of opportunity (SoOps). Coastal sea surface height plays a prominent role in measuring the total water-level envelope directly and is one of the key quantities required by storm surge applications and services. Nadir satellite altimeters have a long history of mapping the variability of the earth’s open ocean. However, they exhibit problems operating in coastal areas due to the effects, such as land contamination, rapid variations due to tides, and atmospheric effects. One technique for filling this gap is bistatic altimetry using SoOp (e.g., digital communication signal reflections). In this letter, we investigate capabilities of this technique. Twenty three days of data were collected at platform harvest from a single channel of the Ku-Band direct broadcast satellite. The wind speed observed during the experiment was between 4 and 14 m/s and significant wave height was between 0.7 and 4 m as measured by buoy 46 218 located 8 km away. The standard deviation in the estimation of height was found to be 7.2 cm (the same as predicted from theory). Using a least-squares approach improved the precision reducing the standard deviation to 6.8 cm. It is shown that the error in the estimation of height can be reduced to 3.5 cm by utilizing the full bandwidth (all the channels) of the SoOp. Extrapolating these results, we predict a precision of 5.3 cm from a typical (e.g., Jason) orbit of 1380 km.
Autors: Rashmi Shah;James L. Garrison;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1840 - 1844
Publisher: IEEE
 
» Precoder Design for Simultaneous Wireless Information and Power Transfer Systems With Finite-Alphabet Inputs
Abstract:
Existing research on a simultaneous wireless information and power transfer (SWIPT) system is based on the assumption of Gaussian inputs. However, the optimal design on Gaussian inputs may lead to dramatic performance loss for practical systems with finite-alphabet inputs. This paper focuses on the precoder design for a SWIPT system with finite-alphabet inputs and instantaneous channel state information over a multiple-input multiple-output channel. We formulate the optimal precoder design as an optimization problem, in which the objective is to maximize the mutual information over the channel from the transmitter to the information receiver under the constraints of transmit power and harvested energy threshold. The formulated problem is NP-hard, so a global optimal solution cannot be found within the polynomial time. The main contributions of this paper are as follows: 1) By using its structure, the NP-hard problem is relaxed to a semidefinite programming problem. Then, a general solving framework for both co-located and separated receiver cases, based on the semidefinite relaxation (SDR) technique, is developed to achieve a near optimal precoder. 2) For the case of co-located receivers, we show that the optimal precoder design is a concave problem with respect to power allocation; then, a specific algorithm for co-located receivers is proposed. Compared with the general SDR-based method, the specific algorithm for co-located receivers exhibits almost the same performance but much lower complexity. 3) The performance of several practical co-located receiver designs is analyzed in SWIPT systems with finite-alphabet inputs. Finally, we provide simulation results to show the efficacy of the proposed algorithms.
Autors: Xiaodong Zhu;Weiliang Zeng;Chengshan Xiao;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 9085 - 9097
Publisher: IEEE
 
» Predicting Forest Evapotranspiration by Coupling Carbon and Water Cycling Based on a Critical Stomatal Conductance Model
Abstract:
Quantifying forest evapotranspiration (ET) is essential for understanding of climatic response of forest carbon and water cycling. However, there are still large uncertainties in forest ET predictions, especially in plant transpiration (PT). The poor estimations of forest ET and PT are largely attributed to the neglect of wet canopy evaporation and uncertainties in the stomatal conductance. Thus, by coupling a revised Ball—Woodrow–Berry (BWB) model, a precipitation intercepted algorithm and the gross primary production (GPP) model to Shuttleworth–Wallace (SW) model, this study introduced a modified SW model. The performances of this model were subsequently tested in three different forest sites with long-term observed records. Compared with previous models, had a canopy stomatal scheme with stronger ecological significance and simpler GPP estimation scheme. Our analyses reveal the following. 1) evidently improves the agreements between estimated and measured ET compared to original SW (R2 increasing by 0.19–0.68). could more accurately partition PT and evaporation, when compared with an earlier BWB-based SW (R2 increasing by ∼0.03). This finding also supports the use of Lohammer function in semiempirical model of stomatal conductance. 2) Accurate predictions of GPP are helpful for improving ET estimations in , suggesting that carbon and water fluxes are inherently linked. 3) In addition to GPP, leaf area index evidently affects the performances of estimated ET in . These results suggest that critically coupling carbon and water cycling are very important for improving forest ET prediction.
Autors: Zhengjia Liu;Chaoyang Wu;Sisi Wang;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Oct 2017, volume: 10, issue:10, pages: 4469 - 4477
Publisher: IEEE
 
» Predicting Linear Elongation With Conductive Thread-Based Sensors
Abstract:
Conductive thread-based sensors have the potential to offer ambulatory measurement of body movement and posture. While such sensors have been previously described in terms of their overall correlation with existing measurement modalities, the ability of thread-based sensors to predict linear elongation has yet to be investigated. We constructed multiple stitched sensors, 20 cm in length, using two silver-coated nylon threads and seven different types of stitches, including cover and overlock stitches. Stitched sensors underwent elongation and cyclic stress tests while sensor resistance was recorded. Optimal predictive functions were derived for each sensor such that the range-normalized error was minimized. Responses were found to be governed by the combination of stitch geometry and physical properties of the threads. The average error in predicting elongation was 14% of the usable sensor range, suggesting that the stitched sensors are perhaps better suited to intermittent detection of stretched versus unstretched states rather than continuous prediction of absolute elongation. Nonetheless, coverstitches were generally superior to overlock stitches in terms of minimizing range-normalized error. The path of the conductive looper thread and the presence of stabilizing needle threads were important determinants of the sensor’s prediction capability and repeatability. Stress tests revealed a systematic upward drift of the resistance response curve for all sensors over repeated trials, suggesting that these stitched sensors require adequate recovery time between measurements. Given the possibility of applying stitched sensors non-destructively to existing garments, further study of these sensors—particularly those comprising multiple independent stitches in novel stitch geometries—remains worthwhile.
Autors: Amanda Fleury;Madison Cohen-McFarlane;Yan To Ling;Tom Chau;
Appeared in: IEEE Sensors Journal
Publication date: Oct 2017, volume: 17, issue:20, pages: 6537 - 6548
Publisher: IEEE
 
» Predicting nsSNPs that Disrupt Protein-Protein Interactions Using Docking
Abstract:
The human genome contains a large number of protein polymorphisms due to individual genome variation. How many of these polymorphisms lead to altered protein-protein interaction is unknown. We have developed a method to address this question. The intersection of the SKEMPI database (of affinity constants among interacting proteins) and CAPRI 4.0 docking benchmark was docked using HADDOCK, leading to a training set of 166 mutant pairs. A random forest classifier based on the differences in resulting docking scores between the 166 mutant pairs and their wild-types was used, to distinguish between variants that have either completely or partially lost binding ability. Fifty percent of non-binders were correctly predicted with a false discovery rate of only 2 percent. The model was tested on a set of 15 HIV-1 – human, as well as seven human- human glioblastoma-related, mutant protein pairs: 50 percent of combined non-binders were correctly predicted with a false discovery rate of 10 percent. The model was also used to identify 10 protein-protein interactions between human proteins and their HIV-1 partners that are likely to be abolished by rare non-synonymous single-nucleotide polymorphisms (nsSNPs). These nsSNPs may represent novel and potentially therapeutically-valuable targets for anti-viral therapy by disruption of viral binding.
Autors: Norman Goodacre;Nathan Edwards;Mark Danielsen;Peter Uetz;Cathy Wu;
Appeared in: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Publication date: Oct 2017, volume: 14, issue:5, pages: 1082 - 1093
Publisher: IEEE
 
» Prediction of Sea Surface Temperature Using Long Short-Term Memory
Abstract:
This letter adopts long short-term memory (LSTM) to predict sea surface temperature (SST), and makes short-term prediction, including one day and three days, and long-term prediction, including weekly mean and monthly mean. The SST prediction problem is formulated as a time series regression problem. The proposed network architecture is composed of two kinds of layers: an LSTM layer and a full-connected dense layer. The LSTM layer is utilized to model the time series relationship. The full-connected layer is utilized to map the output of the LSTM layer to a final prediction. The optimal setting of this architecture is explored by experiments and the accuracy of coastal seas of China is reported to confirm the effectiveness of the proposed method. The prediction accuracy is also tested on the SST anomaly data. In addition, the model’s online updated characteristics are presented.
Autors: Qin Zhang;Hui Wang;Junyu Dong;Guoqiang Zhong;Xin Sun;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1745 - 1749
Publisher: IEEE
 
» Predictive Controller Based on Switching State Grouping for a Modular Multilevel Converter With Reduced Computational Time
Abstract:
Recently, a modular multilevel converter (MMC) has become one of the most popular converters in medium/high-power applications. In this paper, a new technique is presented to decrease the computational time of the MMC by using switching state grouping for the predictive controller. The proposed technique has the ability to control the output current, minimize the circulating currents, and balance all capacitor voltages, simultaneously. For a predefined number of MMC submodules, the number available switching states is known. The proposed technique uses two stages of predictive modules. In the first stage, the switching states of the MMC are divided equally into a number of groups, controlled simultaneously by the same number of predictive modules. The optimal number of the switching state groups in the first stage is obtained. In the second stage, only one predictive module is used to obtain the optimal switching state of the MMC without any other complexities or additional sorting controllers. The effectiveness of the proposed control technique has been verified by using MATLAB/SIMULINK software considering steady state and dynamic analysis. The results of the proposed technique are compared with the conventional one in terms of computation time, verifying better performance of the proposed method.
Autors: Ahmed Rashwan;Mahmoud A. Sayed;Youssef A. Mobarak;Gaber Shabib;Tomonobu Senjyu;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Oct 2017, volume: 32, issue:5, pages: 2189 - 2198
Publisher: IEEE
 
» Predictive Evaluation of Ship Collision Risk Using the Concept of Probability Flow
Abstract:
This paper presents a semianalytical approach for evaluating the collision risk between two moving surface ships. The concept of probability flow is introduced to develop an analytically sound problem formulation, which allows for an accurate estimation of collision probability considering time-varying ship trajectory uncertainties. For efficient computation, the flow of collision probability is separated into diffusion and drift components. These two probability components are combined to obtain the instantaneous collision probability, and this instantaneous probability is integrated in time to quantify the expected risk of collision. To demonstrate the feasibility of the proposed approach, traffic simulations are performed for several representative maritime traffic scenarios and the obtained simulation results are discussed.
Autors: Jeonghong Park;Jinwhan Kim;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Oct 2017, volume: 42, issue:4, pages: 836 - 845
Publisher: IEEE
 
» Preliminary Studies With Augmented Reality Tool To Help In Psycho-pedagogical Tasks With Children Belonging To Autism Spectrum Disorder
Abstract:
The paper aims to show current efforts done towards the development of a tool for helping children affected with Autism Spectrum Disorder (ASD). We introduce the use of Augmented Reality-based tools, basically the Google Cardboard head-mounted display, in psycho-pedagogical tasks and tests performed with these children. We analysed the relationships about the possible increasing in executive functions when they have their facial processing cushioned by using the Google cardboard and looking into the real world just like a cartoon. This initial study provides evidences towards verifying that these children have a particular interest when real faces are covered with cartoon faces. The achieved results suggest that the proposed environment helps to increasing the performance of children in psycho-pedagogical tasks and that it can be a useful tool for helping professional educators in their tasks of giving a better support to these children in the development of their executive functions
Autors: Kerolayne Paiva Soares;Aquiles Medeiros Filgueira Burlamaqui;Luiz Marcos Garcia Goncalves;Viviane Ferreira da Costa;Maria Edna Cunha;Akynara Aglae Rodrigues Santos da Silva Burlamaqui;
Appeared in: IEEE Latin America Transactions
Publication date: Oct 2017, volume: 15, issue:10, pages: 2017 - 2023
Publisher: IEEE
 
» Preserving Virtual Memory by Mitigating the Address Translation Wall
Abstract:
The concept of virtual memory is one of the classic computer science abstractions and has long enabled systems that are easy to program and that operate quickly. Today, however, virtual memory faces challenges that pose a threat to the continued progress of computing. This article discusses these threats and presents some promising ways to counter them.
Autors: Abhishek Bhattacharjee;
Appeared in: IEEE Micro
Publication date: Oct 2017, volume: 37, issue:5, pages: 6 - 10
Publisher: IEEE
 
» Primary Channel Gain Estimation for Spectrum Sharing in Cognitive Radio Networks
Abstract:
In cognitive radio networks, the channel gain between primary transceivers, namely, primary channel gain, is crucial for a cognitive transmitter (CT) to control the transmit power and achieve spectrum sharing. Conventionally, the primary channel gain is estimated in the primary system, and thus unavailable at the CT. To deal with the issue, two estimators are proposed by enabling the CT to sense primary signals. In particular, by adopting the maximum likelihood (ML) criterion to analyze the received primary signal, an ML estimator is first developed. To reduce the computational complexity of the ML estimator, a median-based (MB) estimator is then proposed. By comparing the ML estimator and the MB estimator from the aspects of the computational complexity as well as the estimation accuracy, both advantages and disadvantages of two estimators are revealed. Simulation results show that the estimation errors of both estimators can be as small as 0.015. Meanwhile, the ML estimator outperforms the MB estimator in terms of the estimation accuracy if the sensed primary signal at the CT is weak. Otherwise, the MB estimator is superior to the ML estimator from the aspects of both the computational complexity and the estimation accuracy.
Autors: Lin Zhang;Guodong Zhao;Wenli Zhou;Liying Li;Gang Wu;Ying-Chang Liang;Shaoqian Li;
Appeared in: IEEE Transactions on Communications
Publication date: Oct 2017, volume: 65, issue:10, pages: 4152 - 4162
Publisher: IEEE
 
» Prior-Information-Based Finite-Frequency $\text{H}_{\infty}$ Control for Active Double Pantograph in High-Speed Railway
Abstract:
The fluctuation in contact force between the pantograph and the catenary severely affects the current collection quality of electric multiple units in high-speed railway. In particular, when double pantographs operate simultaneously, the contact force on trailing pantograph (TP) fluctuates violently due to the passage of leading pantograph (LP). To address this problem, a prior-information-based finite-frequency controller, incorporating an adaptive estimator, is proposed for the active control of double pantographs in this paper. As the prior information is of great importance, the frequency characteristics of contact force are analyzed based on power spectrum density and utilized in calculating the control gain matrix. The finite-frequency control is employed to decrease the contact force fluctuation within the concerned frequency range with limited control force. Considering the unknown and time-varying noise statistic, an adaptive cubature Kalman filter is presented to estimate the states of pantographs. The effectiveness and robustness of the proposed control strategy are evaluated with implementations in a nonlinear double-pantograph-catenary system model under different operational conditions. The results show that, for both LP and TP, the control strategy can adequately decrease the contact force fluctuation. Particularly, it has a good capability to reject parameter perturbations and external disturbance.
Autors: Xiaobing Lu;Zhigang Liu;Jing Zhang;Hongrui Wang;Yang Song;Fuchuan Duan;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 8723 - 8733
Publisher: IEEE
 
» Privacy-Preserving Location Sharing Services for Social Networks
Abstract:
A common functionality of many location-based social networking applications is a location sharing service that allows a group of friends to share their locations. With a potentially untrusted server, such a location sharing service may threaten the privacy of users. Existing solutions for Privacy-Preserving Location Sharing Services (PPLSS) require a trusted third party that has access to the exact location of all users in the system or rely on expensive algorithms or protocols in terms of computational or communication overhead. Other solutions can only provide approximate query answers. To overcome these limitations, we propose a new encryption notion, called Order-Retrievable Encryption (ORE), for PPLSS for social networking applications. The distinguishing characteristics of our PPLSS are that it (1) allows a group of friends to share their exact locations without the need of any third party or leaking any location information to any server or users outside the group, (2) achieves low computational and communication cost by allowing users to receive the exact location of their friends without requiring any direct communication between users or multiple rounds of communication between a user and a server, (3) provides efficient query processing by designing an index structure for our ORE scheme, (4) supports dynamic location updates, and (5) provides personalized privacy protection within a group of friends by specifying a maximum distance where a user is willing to be located by his/her friends. Experimental results show that the computational and communication cost of our PPLSS is much better than the state-of-the-art solution.
Autors: Roman Schlegel;Chi-Yin Chow;Qiong Huang;Duncan S. Wong;
Appeared in: IEEE Transactions on Services Computing
Publication date: Oct 2017, volume: 10, issue:5, pages: 811 - 825
Publisher: IEEE
 
» Proactive Drone-Cell Deployment: Overload Relief for a Cellular Network Under Flash Crowd Traffic
Abstract:
This paper is concerned with providing radio access network (RAN) elements (supply) for flash crowd traffic demands. The concept of multi-tier cells [heterogeneous networks (HetNets)] has been introduced in 5G network proposals to alleviate the erratic supply–demand mismatch. However, since the locations of the RAN elements are determined mainly based on the long-term traffic behavior in 5G networks, even the HetNet architecture will have difficulty in coping up with the cell overload induced by flash crowd traffic. In this paper, we propose a proactive drone-cell deployment framework to alleviate overload conditions caused by flash crowd traffic in 5G networks. First, a hybrid distribution and three kinds of flash crowd traffic are developed in this framework. Second, we propose a prediction scheme and an operation control scheme to solve the deployment problem of drone cells according to the information collected from the sensor network. Third, the software-defined networking technology is employed to seamlessly integrate and disintegrate drone cells by reconfiguring the network. Our experimental results have shown that the proposed framework can effectively address the overload caused by flash crowd traffic.
Autors: Peng Yang;Xianbin Cao;Chao Yin;Zhenyu Xiao;Xing Xi;Dapeng Wu;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Oct 2017, volume: 18, issue:10, pages: 2877 - 2892
Publisher: IEEE
 
» Proactive Radio Resource Optimization With Margin Prediction: A Data Mining Approach
Abstract:
Driven by the exponential surge on high data rate services, network operators are facing the challenges of how to enhance the capacity and optimize the coverage in a cost-efficient approach. However, traditional network optimization technologies passively adjust the network configurations based on network's congestion ratio, drop-off rate, coverage holes, etc., leading to suboptimum user experiences. Therefore, the objective of this paper is to optimize the network configurations by obtaining the accurate network status, user demand, and application request distribution based on the real-time data. The data mining technique is introduced to predict the resource margin based on historical measurement statistics. To explore the dynamic distribution of user demand and application request, a weighted k-nearest neighbors model is proposed to predict periodic characteristics of network traffics, denoting different temporal and spatial patterns of radio resource margins. In contrast to the traditional passive network optimization approaches, the radio resources can be reconfigured actively to meet the dynamic patterns of traffic loads by using the proposed optimization algorithm. Results prove that the proposed data mining model can capture the dynamics of traffic loads to optimize the traffic load balance and increase the efficiency of radio resource utilization using the network statistic data.
Autors: Zhiyong Feng;Xi Li;Qixun Zhang;Wei Li;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 9050 - 9060
Publisher: IEEE
 
» Probabilistic and Distributed Control of a Large-Scale Swarm of Autonomous Agents
Abstract:
We present a distributed control algorithm simultaneously solving both the stochastic target assignment and optimal motion control for large-scale swarms to achieve complex formation shapes. Our probabilistic swarm guidance using inhomogeneous Markov chains (PSG–IMC) algorithm adopts a Eulerian density-control framework, under which the physical space is partitioned into multiple bins and the swarm's density distribution over each bin is controlled in a probabilistic fashion to efficiently handle loss or the addition of agents. We assume that the number of agents is much larger than the number of bins and that each agent knows in which bin it is located, the desired formation shape, and the objective function and motion constraints. PSG–IMC determines the bin-to-bin transition probabilities of each agent using a time IMC. These time-varying Markov matrices are computed by each agent in real time using the feedback from the current swarm distribution, which is estimated in a distributed manner. The PSG–IMC algorithm minimizes the expected cost of transitions per time instant that are required to achieve and maintain the desired formation shape, even if agents are added to or removed from the swarm. PSG–IMC scales well with a large number of agents and complex formation shapes and can also be adapted for area exploration applications. We demonstrate the effectiveness of this proposed swarm guidance algorithm by using numerical simulations and hardware experiments with multiple quadrotors.
Autors: Saptarshi Bandyopadhyay;Soon-Jo Chung;Fred Y. Hadaegh;
Appeared in: IEEE Transactions on Robotics
Publication date: Oct 2017, volume: 33, issue:5, pages: 1103 - 1123
Publisher: IEEE
 
» Probabilistic Automata Model of a Soft Robot for the Planning of Manipulation Tasks
Abstract:
Soft robots must be able to structure an automation problem into a sequence of actions that lead to a desired state, before they can fulfill a meaningful role in automation applications. This, however, can only be successful if the robot can predict the outcome of an action. The theory of rigid industrial robots is not applicable without major changes, because kinematic chains do not adequately describe the continuous deformation of the complex, often biologically inspired shapes of soft robots. Analytic solutions have not been found yet. Numerical solutions based on finite elements are slow, technically challenging, and only suitable for one specific robot. It is, however, possible to observe the outcome of an action, and use these observations to plan a sequence of actions that let the robot accomplish an automation task. In this paper, we analyze a probabilistic automaton that computes the optimal sequence of actions to bring the robot into a desired state. An earlier article explained the functioning of the method in a toy example. In this paper, we analyze if it is feasible to apply the method to a planning problem inspired by a real soft robot. We show the results and document the planning process. We identify the analog of an impulse response, although it is not closed form due to the nonparametric nature of the method.

Note to Practitioners—A soft robotic sorting table has a computer-controlled soft surface that can move delicate objects without damaging them. There are currently no closed-loop control systems for such robots, because it is unclear how to relate the control signals to the behavior of the table, or which actions to choose in order to solve a manipulation task. In this paper, we propose a probabilistic automaton to plan the best action sequence on average. The sequence brings the workpieces on top of a soft table into a desired condition. It is a machine learning solution that is based on observations- of the input signals and their effect, rather than a detailed analytical or numerical modeling of the robot. We show that it is feasible to model an existing soft robotic table. We demonstrate that the planning is successful by solving complex maze tasks. Our results are based on experiments and simulations.

Autors: Martin Stommel;Zhicong Deng;Weiliang L. Xu;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Oct 2017, volume: 14, issue:4, pages: 1722 - 1730
Publisher: IEEE
 
» Probabilistic Hosting Capacity for Active Distribution Networks
Abstract:
The increased connection of distributed generation (DG), such as photovoltaic (PV) and wind turbine (WT), has shifted the current distribution networks from being passive (consuming energy) into active (consuming/producing energy). However, there is still no consensus about how to determine the maximum amount of DGs that are allowed to be connected, i.e., how to quantify a so-called “hosting capacity” (HC). Therefore, this paper proposes a novel risk assessment tool for estimating network HC by considering uncertainties associated with PV, WT, and loads. This evaluation is performed using the likelihood approximation approach. The paper, also, proposes a utilization of clearness index for localized solar irradiance prediction of PV. In addition, we propose the use of sparse grid technique as an effective means for uncertainty computation while the use of Monte Carlo technique is taken for a comparison purpose. Two actual distribution networks (11-buses and South Australian large feeder) are considered as case studies to demonstrate the usefulness of the proposed tool.
Autors: Hassan Al-Saadi;Rastko Zivanovic;Said F. Al-Sarawi;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2519 - 2532
Publisher: IEEE
 
» Probabilistic Key Predistribution in Mobile Networks Resilient to Node-Capture Attacks
Abstract:
We present a comprehensive analysis on connectivity and resilience of secure sensor networks under the widely studied -composite key predistribution scheme. For network connectivity, which ensures that any two sensors can find a path in between for secure communication, we derive the conditions to guarantee connectivity in consideration of: 1) node-capture attacks, where the adversary may capture a set of sensors and compromise keys in their memory; 2) sensor mobility, meaning that sensors can move around so that the network topology may change over time; 3) physical transmission constraints, under which two sensors have to be within each other’s transmission range for communication; 4) the boundary effect of network fields; and 5) link unreliability, meaning that links are allowed to be unreliable. In contrast, many prior connectivity analyses of secure sensor networks often ignore the above issues. For resilience, although limited studies have presented formal analysis, it is often assumed that the adversary captures a random set of sensors, whereas this paper allows the adversary to capture an arbitrary set of sensors. We present conditions to ensure unassailability and unsplittability in secure sensor networks under the -composite scheme. Unassailability ensures that an adversary capturing any set consisting of a negligible fraction of sensors can compromise only a negligible fraction of communication links although the adversary may compromise communications between non-captured nodes, which happen to use keys that are shared by captured nodes. Unsplittability means that when a negligible fraction of sensors are captured, almost all of the remaining nodes are still securely connected. Based on the results of connectivity, unassailability, and un- plittability, we provide useful guidelines for the design of secure sensor networks.
Autors: Jun Zhao;
Appeared in: IEEE Transactions on Information Theory
Publication date: Oct 2017, volume: 63, issue:10, pages: 6714 - 6734
Publisher: IEEE
 
» Probing the Critical Region of Conductive Filament in Nanoscale HfO2 Resistive-Switching Device by Random Telegraph Signals
Abstract:
Resistive-switching random access memory (RRAM) is widely considered as a disruptive technology. Despite tremendous efforts in theoretical modeling and physical analysis, details of how the conductive filament (CF) in metal-oxide-based filamentary RRAM devices is modified during normal device operations remain speculative, because direct experimental evidence at defect level has been missing. In this paper, a random-telegraph-signal-based defect-tracking technique (RDT) is developed for probing the location and movements of individual defects and their statistical spatial and energy characteristics in the CF of state-of-the-art hafnium-oxide RRAM devices. For the first time, the critical filament region of the CF is experimentally identified, which is located near, but not at, the bottom electrode with a length of nanometer scale. We demonstrate with the RDT technique that the modification of this key constriction region by defect movements can be observed and correlated with switching operation conditions, providing insight into the resistive switching mechanism.
Autors: Zheng Chai;Jigang Ma;Wei Dong Zhang;Bogdan Govoreanu;Jian Fu Zhang;Zhigang Ji;Malgorzata Jurczak;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4099 - 4105
Publisher: IEEE
 
» Process Mining to Discover Shoppers’ Pathways at a Fashion Retail Store Using a WiFi-Base Indoor Positioning System
Abstract:
We present a preliminary report of a customer pathway analysis in an off-line store. Smart phone WiFi-based positioning technology is used to identify each customer’s pathway behavior. The log data containing the space-time information are analyzed using process mining, a tool that provides a comprehensive view of an entire process. The main benefit of process mining is that it provides the topological structure of the processes. We installed a WiFi signal-capturing device in a retail store of a fashion brand in South Korea and collected data over a two-month period. Halfway through the experimental period, we swapped a set of mannequins displayed at the entrance to the store with an item stand. We then compared the customers’ pathway behavior before and after the change. Through an analysis based on process mining, we observed a change in the topological structure of the pathway behavior following the change in the display setting. This paper demonstrates the possibilities of analyzing customer behavior using WiFi-based technology and the process mining technique.

Note to Practitioners—The main goal of this paper is to demonstrate the possibility of WiFi-based positioning technology and analytical methodology for analyzing indoor movement in the era of Big Data and the Internet of Things. Recently, with advances in communication, sensors, and wearable computing technologies, strong interest has been shown in marketing and retail behavior studies that can capture customer travel data in off-line stores to inform and improve sales and marketing. As the application of off-line store behavior analysis for behavior studies and marketing gains momentum, this paper can be used as a foundation for the development of sensor-based location analysis systems or devices for off-line stores. The focus of this paper is not to investigate customer behavior related to the display change nor the behavio- al science related to retail. Rather, we experimentally demonstrate the value of the proposed technology and the process mining technique for future research.

Autors: Illhoe Hwang;Young Jae Jang;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Oct 2017, volume: 14, issue:4, pages: 1786 - 1792
Publisher: IEEE
 
» Process/Voltage/Temperature-Variation-Aware Design and Comparative Study of Transition-Detector-Based Error-Detecting Latches for Timing-Error-Resilient Pipelined Systems
Abstract:
Among timing-error-detecting registers, the transition-detector-based error-detecting latch (TD-EDL) is regarded as the most lightweight design. To realize a truly variation-resilient system, a TD-EDL should be designed to be robust across all process/voltage/temperature (PVT) corners. In particular, its detection window deviation must be carefully compensated for an accurate detection. It must also be small, as well as power and energy efficient, to prevent excessive overheads. This paper carefully redesigned several conventional TDs in 28-nm CMOS process, and postlayout simulations were performed to examine the pros and cons of the TDs. According to the characteristics of each TD, the transistor sizing methods were explored to achieve PVT-variation-aware designs. The redesigned TDs were then used to construct TD-EDLs, for which the causes of detection window deviation were examined and improved upon. The timing characteristics that affect the correct function and appropriate responses were discussed, and the area overhead, timing performance, power consumption, and voltage scalability of the TD-EDLs were evaluated and compared.
Autors: Jinn-Shyan Wang;Shih-Nung Wei;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Oct 2017, volume: 25, issue:10, pages: 2893 - 2906
Publisher: IEEE
 
» Propagation Factors of Partially Coherent Model Beams in Oceanic Turbulence
Abstract:
Based on the extended Huygens–Fresnel principle and second-order moments of the Wigner distribution function, we have derived the analytical expressions of the propagation factor of four kinds of partially coherent model beams in oceanic turbulence, including Gaussian Schell-model (GSM), Bessel–Gaussian Schell-model, Laguerre–Gaussian Schell-model, and cosine-Gaussian Schell-model (CGSM). It is found that the modulation of the spectral degree of coherence takes advantage over the GSM beams for reducing the turbulence-induced degradation. The beams with larger index (, , ), initial beamwidth, and the wavelength or the smaller coherent length will be less affected by the oceanic turbulence. In addition, the influences of the oceanic parameters on the beam quality are discussed in detail, and the degradation of beams can be enhanced with the decrease of the rate of dissipation of turbulence kinetic energy per unit mass of fluid and the increase of the rate of dissipation of mean-square temperature, also the salinity fluctuation has greater contribution to the decrease of the beam quality than that of the temperature fluctuation. Moreover, the comparison of the normalized propagation factor of the four kinds of beams demonstrates that the CGSM is more robust against the oceanic turbulence than other partially coherent model beams. Our results can be helpful in the design of an optical communication system in an oceanic environment.
Autors: Xianwei Huang;Yanfeng Bai;Xiquan Fu;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 11
Publisher: IEEE
 
» Propagation-Delay-Aware Unslotted Schedules With Variable Packet Duration for Underwater Acoustic Networks
Abstract:
Recent advances in scheduling transmissions for underwater acoustic networks utilize and exploit long propagation latency of acoustic waves for achieving throughput gain. These techniques utilize the propagation delay information of the considered network geometry and schedule transmissions in time slots. Time-slotted transmissions are such that most of the interference overlaps with the transmission slots and the receiving slots are interference free. Moreover, exploiting propagation delays lead to multiple transmissions per time slot, thereby resulting in higher throughput. However, the packet duration of each transmission in the time slot is assumed to be fixed. The packet duration, however, provides a degree of freedom that, if utilized, results in strategies that can be adopted to achieve throughput closer to the established upper bound. Therefore, we consider the problem of finding unslotted transmission schedules allowing unequal packet duration. Given the propagation delay between nodes in the network and packet traffic demands, we formulate an optimization problem for minimizing the fractional idle time in a frame (or period) of the schedule as a mixed-integer linear fractional problem (MILFP). We compare our results to the recent advancements that exploit large propagation delays and result in time-slotted and unslotted schedules with fixed packet duration. We also present schedules computed for various network geometries with arbitrary packet traffic demands.
Autors: Prasad Anjangi;Mandar Chitre;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Oct 2017, volume: 42, issue:4, pages: 977 - 993
Publisher: IEEE
 
» Prophet: A Parallel Instruction-Oriented Many-Core Simulator
Abstract:
Most existing computer architecture simulators are cycle oriented, i.e., they are driven cycle by cycle. However, frequent switches among simulation contexts, excessive buffer accesses and tightly coupled manner often make such an architecture simulator slow, difficult to parallelize and hard to scale to large-scale many-core systems. In this paper, we propose Prophet, a parallel instruction-oriented simulation framework for many-cores. Prophet adopts a general instruction-oriented model to simulate processor cores, in which a simulator is built from the perspective of each simulated instruction impacting a small number of relevant processor components, as opposed to that of a large number of processor components executing many instructions in each cycle as in the cycle-oriented approach. Prophet determines the execution cycle of a simulated instruction based on the states of the relevant components impacted by the instruction, and update the components states after the execution of the instruction. Prophet also adopts a speculative model to decouple private resources from the shared resources (e.g., shared cache), which avoids unnecessary interactions between them and only pays a penalty upon a rare mis-speculation. We have designed and implemented a prototype of Prophet that supports both user-level and full-system simulation. Experimental results show Prophet can scale up to simulate thousands of simulated cores (4,096 cores in the current implementation) with good performance and small accuracy loss. It achieves average simulation speeds of about 98 and 235 MIPS (millions of simulated instructions per second) for full-system and user-level simulation, respectively, with only 3 percent IPC error rate and negligible deviation in cache simulation results. When run on a many-core platform (i.e., Intel Xeon Phi), it achieved an average simulation speed of about 413 MIPS.
Autors: Weihua Zhang;Xiaofeng Ji;Yunping Lu;Haojun Wang;Haibo Chen;Pen-Chung Yew;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Oct 2017, volume: 28, issue:10, pages: 2939 - 2952
Publisher: IEEE
 
» Prospective Fall-Risk Prediction Models for Older Adults Based on Wearable Sensors
Abstract:
Wearable sensors can provide quantitative, gait-based assessments that can translate to point-of-care environments. This investigation generated elderly fall-risk predictive models based on wearable-sensor-derived gait data and prospective fall occurrence, and identified the optimal sensor type, location, and combination for single and dual-task walking. 75 individuals who reported six month prospective fall occurrence (75.2 ± 6.6 years; 47 non-fallers and 28 fallers) walked 7.62 m under single-task and dual-task conditions while wearing pressure-sensinginsoles and tri-axial accelerometers at the head, pelvis, and left and right shanks. Fall-risk classificationmodels were assessed for all sensor combinations and three model types: neural network, naïve Bayesian, and support vector machine. The best performing model used a neural network, dual-task gait data, and input parameters from head, pelvis, and left shank accelerometers (accuracy = 57%, sensitivity = 43%, and specificity = 65%). The best single-sensor model used a neural network, dual-task gait data, and pelvis accelerometer parameters (accuracy = 54%, sensitivity = 35%, and specificity = 67%). Single-task and dual-task gait assessments provided similar fall-risk model performance. Fall-risk predictive models developed for point-of-care environments should use multi-sensor dual-task gait assessment with the pelvis location considered if assessment is limited to a single sensor.
Autors: Jennifer Howcroft;Jonathan Kofman;Edward D. Lemaire;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Oct 2017, volume: 25, issue:10, pages: 1812 - 1820
Publisher: IEEE
 
» Prototyping of Nonlinear Time-Stepped Finite Element Simulation for Linear Induction Machines on Parallel Reconfigurable Hardware
Abstract:
The finite element method (FEM) is widely used for accurate design and analysis of electric machines; however, it suffers from long execution time. In this paper, for the first time hardware acceleration of two-dimensional FEM for a single-sided linear induction motor on the field programmable gate array (FPGA) is proposed. The nonlinearity of the iron core as well as the movement are taken into consideration. A new sparse solver is proposed based on left-looking Gilbert-Peierls algorithm for the system of linear equations of FEM that need to be solved in different iterations and time steps. Implementation of the model is performed in a massively paralleled and deeply pipelined hardware architecture using VHDL coding with single precision floating-point number representation. The proposed emulation was performed at various time steps resulting in significant average speedup of 9.73 times in comparison with JMAG-Designer as a commercial finite element software, and the overall hardware latency of each time step for the emulation was 49.2 ms in average with minimum achievable FPGA clock of 5.59 ns.
Autors: Behzad Jandaghi;Venkata Dinavahi;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 7711 - 7720
Publisher: IEEE
 
» Pseudo-Sequence-Based 2-D Hierarchical Coding Structure for Light-Field Image Compression
Abstract:
In this paper, we propose a pseudo-sequence-based two-dimensional (2-D) hierarchical coding structure for light-field image compression. In the proposed scheme, we first decompose the light-field image into multiple views and organize them into a 2-D coding structure according to the spatial coordinates of the corresponding microlens. Then, we mainly develop three algorithms to optimize the 2-D coding structure. First, we propose a 2-D hierarchical coding structure with a limited number of reference frames to exploit the intercorrelations among various views. To be more specific, we divide all the views into four quadrants, and all the views are encoded one quadrant after another to reduce the reference buffer size as much as possible. Inside each quadrant, all the views are encoded hierarchically in both horizontal and vertical directions to fully exploit the correlations among different views. Second, we propose to use the distance between the current view and its reference views instead of the picture order count difference as the criterion for selecting better reference frames for each inter view. The distance-based criterion is also applied to the motion vector scaling process to obtain more accurate motion vector predictors. Third, an optimal bit allocation algorithm taking the influence of the various views on the following encoding views into account is proposed to further exploit the intercorrelations among various views and improve coding efficiency. The entire scheme is implemented in the reference software of high efficiency video coding. The experimental results demonstrate that the proposed novel pseudo-sequence-based 2-D hierarchical structure can achieve maximum 28.4% bit-rate savings compared with the previous pseudo-sequence-based light-field image compression method.
Autors: Li Li;Zhu Li;Bin Li;Dong Liu;Houqiang Li;
Appeared in: IEEE Journal of Selected Topics in Signal Processing
Publication date: Oct 2017, volume: 11, issue:7, pages: 1107 - 1119
Publisher: IEEE
 
» PSPEL: In Silico Prediction of Self-Interacting Proteins from Amino Acids Sequences Using Ensemble Learning
Abstract:
Self interacting proteins (SIPs) play an important role in various aspects of the structural and functional organization of the cell. Detecting SIPs is one of the most important issues in current molecular biology. Although a large number of SIPs data has been generated by experimental methods, wet laboratory approaches are both time-consuming and costly. In addition, they yield high false negative and positive rates. Thus, there is a great need for in silico methods to predict SIPs accurately and efficiently. In this study, a new sequence-based method is proposed to predict SIPs. The evolutionary information contained in Position-Specific Scoring Matrix (PSSM) is extracted from of protein with known sequence. Then, features are fed to an ensemble classifier to distinguish the self-interacting and non-self-interacting proteins. When performed on Saccharomyces cerevisiae and Human SIPs data sets, the proposed method can achieve high accuracies of 86.86 and 91.30 percent, respectively. Our method also shows a good performance when compared with the SVM classifier and previous methods. Consequently, the proposed method can be considered to be a novel promising tool to predict SIPs.
Autors: Jian-Qiang Li;Zhu-Hong You;Xiao Li;Zhong Ming;Xing Chen;
Appeared in: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Publication date: Oct 2017, volume: 14, issue:5, pages: 1165 - 1172
Publisher: IEEE
 
» Publicly Verifiable Inner Product Evaluation over Outsourced Data Streams under Multiple Keys
Abstract:
Uploading data streams to a resource-rich cloud server for inner product evaluation, an essential building block in many popular stream applications (e.g., statistical monitoring), is appealing to many companies and individuals. On the other hand, verifying the result of the remote computation plays a crucial role in addressing the issue of trust. Since the outsourced data collection likely comes from multiple data sources, it is desired for the system to be able to pinpoint the originator of errors by allotting each data source a unique secret key, which requires the inner product verification to be performed under any two parties’ different keys. However, the present solutions either depend on a single key assumption or powerful yet practically-inefficient fully homomorphic cryptosystems. In this paper, we focus on the more challenging multi-key scenario where data streams are uploaded by multiple data sources with distinct keys. We first present a novel homomorphic verifiable tag technique to publicly verify the outsourced inner product computation on the dynamic data streams, and then extend it to support the verification of matrix product computation. We prove the security of our scheme in the random oracle model. Moreover, the experimental result also shows the practicability of our design.
Autors: Xuefeng Liu;Wenhai Sun;Hanyu Quan;Wenjing Lou;Yuqing Zhang;Hui Li;
Appeared in: IEEE Transactions on Services Computing
Publication date: Oct 2017, volume: 10, issue:5, pages: 826 - 838
Publisher: IEEE
 
» PUMA: An Improved Realization of MODE for DOA Estimation
Abstract:
The method of direction estimation (MODE) offers appealing advantages such as asymptotic efficiency with mild computational complexity and excellent performance in handling coherent signals, which are not shared by conventional subspace-based methods. However, the MODE employs additional assumption and constraints on the symmetry of the root polynomial coefficients, which might cause severe performance degradation in the scenario of low signal-to-noise ratio/small sample size, since any estimation error will be enlarged twice due to the symmetry. Moreover, the standard realization for MODE does not have a closed-form solution for updating its estimates. In this paper, the optimization problem of MODE is proved to be equivalent to that of the principal-eigenvector utiliztion for modal analysis (PUMA) algorithm. We show that PUMA which has closed-form solution, that does not rely on any additional assumption and constraint on the coefficients, is a better surrogate than MODE for minimizing the same cost function. Extensive simulation results are carried out to support our standpoint.
Autors: Cheng Qian;Lei Huang;Mingyang Cao;Junhao Xie;Hing Cheung So;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Oct 2017, volume: 53, issue:5, pages: 2128 - 2139
Publisher: IEEE
 
» Pursuing Photovoltaic Cost-Effectiveness: Absolute Active Power Control Offers Hope in Single-Phase PV Systems
Abstract:
Countries with a considerable number of photovoltaic (PV) installations are facing the challenge of overloading their power grid during peak power production hours if the power infrastructure remains the same. To address this, regulations have been imposed on PV systems to ensure that more active and flexible power control is performed. As an advanced control strategy, absolute active power control (AA PC) can effectively solve overloading issues by limiting the maximum possible PV power to a certain level (i.e., the power limitation) and can also benefit the inverter reliability because of the reduced thermal loading of the power devices. However, its feasibility is challenged by the associated energy losses. An increase in the inverter lifetime and a reduction of the energy yield can alter the cost of energy, demanding an optimization of the power limitation. Therefore, aiming at minimizing the levelized cost of energy (LCOE), this article discusses how to optimize the power limit for the AA PC strategy.
Autors: Yongheng Yang;Eftichios Koutroulis;Ariya Sangwongwanich;Frede Blaabjerg;
Appeared in: IEEE Industry Applications Magazine
Publication date: Oct 2017, volume: 23, issue:5, pages: 40 - 49
Publisher: IEEE
 
» PVR: Patch-to-Volume Reconstruction for Large Area Motion Correction of Fetal MRI
Abstract:
In this paper, we present a novel method for the correction of motion artifacts that are present in fetal magnetic resonance imaging (MRI) scans of the whole uterus. Contrary to current slice-to-volume registration (SVR) methods, requiring an inflexible anatomical enclosure of a single investigated organ, the proposed patch-to-volume reconstruction (PVR) approach is able to reconstruct a large field of view of non-rigidly deforming structures. It relaxes rigid motion assumptions by introducing a specific amount of redundant information that is exploited with parallelized patchwise optimization, super-resolution, and automatic outlier rejection. We further describe and provide an efficient parallel implementation of PVR allowing its execution within reasonable time on commercially available graphics processing units, enabling its use in the clinical practice. We evaluate PVR’s computational overhead compared with standard methods and observe improved reconstruction accuracy in the presence of affine motion artifacts compared with conventional SVR in synthetic experiments. Furthermore, we have evaluated our method qualitatively and quantitatively on real fetal MRI data subject to maternal breathing and sudden fetal movements. We evaluate peak-signal-to-noise ratio, structural similarity index, and cross correlation with respect to the originally acquired data and provide a method for visual inspection of reconstruction uncertainty. We further evaluate the distance error for selected anatomical landmarks in the fetal head, as well as calculating the mean and maximum displacements resulting from automatic non-rigid registration to a motion-free ground truth image. These experiments demonstrate a successful application of PVR motion compensation to the whole fetal body, uterus, and placenta.
Autors: Amir Alansary;Martin Rajchl;Steven G. McDonagh;Maria Murgasova;Mellisa Damodaram;David F. A. Lloyd;Alice Davidson;Mary Rutherford;Joseph V. Hajnal;Daniel Rueckert;Bernhard Kainz;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Oct 2017, volume: 36, issue:10, pages: 2031 - 2044
Publisher: IEEE
 
» QGeo: Q-Learning-Based Geographic Ad Hoc Routing Protocol for Unmanned Robotic Networks
Abstract:
This letter proposes a novel protocol that uses Q-learning-based geographic routing (QGeo) to improve the network performance of unmanned robotic networks. A rapid and reliable network is essential for the remote control and monitoring of mobile robotic devices. However, controlling the network overhead required for route selection and repair is still a notable challenge, owing to high mobility of the devices. To alleviate this problem, we propose a machine-learning-based geographic routing scheme to reduce network overhead in high-mobility scenarios. We evaluate the performance of QGeo in comparison with other methods using the NS-3 simulator. We find that QGeo has a higher packet delivery ratio and a lower network overhead than existing methods.
Autors: Woo-Sung Jung;Jinhyuk Yim;Young-Bae Ko;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2258 - 2261
Publisher: IEEE
 
» QoS-Aware A-MPDU Retransmission Scheme for 802.11n/ac/ad WLANS
Abstract:
The aggregate MAC protocol data unit (A-MPDU) is one of the pivotal aggregation schemes, defined by the IEEE 802.11n/ac/ad, to improve the transmission efficiency of MAC layer. However, A-MPDU scheme is not efficient in error-prone conditions due to its decrease in retransmission aggregation levels. To overcome this problem, a novel QoS-aware A-MPDU retransmission scheme is proposed in this letter. The scheme fully exploits the aggregation level while considering the strict end-to-end delay requirements by QoS applications. In the proposed scheme, the aggregation levels of the retransmitted A-MPDU frames are decided based on the aggregation sliding window strategy, and the expected delay of the proposed scheme and the traditional scheme, respectively, which is calculated through theoretical analysis. The effectiveness of the scheme is demonstrated via experimental evaluation using ns-3.
Autors: Xu Qian;Bin Wu;Tian-Chun Ye;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2290 - 2293
Publisher: IEEE
 
» QoS-Aware Adaptive A-MPDU Aggregation Scheduler for Voice Traffic in Aggregation-Enabled High Throughput WLANs
Abstract:
Currently available IEEE 802.11n implementations do not apply aggregate MAC protocol data unit (A-MPDU) aggregation to voice traffic because of its strict end-to-end delay requirements. When multiple nodes contend to send voice and other lower-priority traffic, 802.11n network faces serious performance degradation problems for two major reasons: i) due to the medium access control (MAC) and physical (PHY) layer overheads of individual short voice packet transmissions, the available network throughput for lower-priority traffic significantly decreases, and ii) increased contention results in high voice packet loss rate (PLR). This paper proposes a QoS-aware adaptive A-MPDU aggregation scheduler for voice traffic in 802.11n/ac WLANs that adaptively applies A-MPDU aggregation to voice traffic based on QoS requirements and periodically obtained average medium access delay and end-to-end delay statistics. Performance evaluations on 20 nodes sending uplink 64Kbps voice and saturated best-effort traffic at 150Mbps PHY rate showed that the proposed scheme achieved 160% throughput improvement compared to default implementations in driver. During the simulations with 50 nodes transmitting at 600Mbps PHY rate, the proposed scheme provided up to 275Mbps throughput against 0.13Mbps by default scheme; the proposed scheme delivered all voice packets (PLR 1/4 0 percent) and over 99.9 percent of them had less than 150ms end-to-end delay.
Autors: Shinnazar Seytnazarov;Young-Tak Kim;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Oct 2017, volume: 16, issue:10, pages: 2862 - 2875
Publisher: IEEE
 
» Quadratic Time-Frequency Transforms-Based Brillouin Optical Time-Domain Reflectometry
Abstract:
Linear and quadratic Time-Frequency (T-F) transforms are proposed for the signal processing of the Brillouin optical time-domain reflectometry, to improve the system performance, in terms of the transition responsivity and frequency resolution. Various T-F transforms, including linear T-F transform (short time Fourier transform) and quadratic transforms (Choi–Williams, Zhao-Atlas-Marks, smoothed pseudo Wigner–Ville, S-method, and adaptive spectrogram) are applied to the experimental backscattered time-domain spontaneous Brillouin signals. Multiple T-F approaches can be jointly applied to efficiently improve the time and frequency resolutions simultaneously. Results show that the SWPV transform provides the best transition responsivity and frequency resolution simultaneously among the six T-F transforms because of its smoothing operations on frequency and time axis for reducing the cross-term interference.
Autors: Yifei Yu;Linqing Luo;Bo Li;Kenichi Soga;Jize Yan;
Appeared in: IEEE Sensors Journal
Publication date: Oct 2017, volume: 17, issue:20, pages: 6622 - 6626
Publisher: IEEE
 
» Qualitative Methods in Inverse Electromagnetic Scattering Theory: Inverse Scattering for Anisotropic Media.
Abstract:
In recent years, a new approach has been developed in the study of the inverse scattering problem for electromagnetic waves. In this approach, a weak scattering assumption has been avoided, and no use has been made of nonlinear optimization methods. Instead, a study is made of the analytic properties of the far-field operator, and the results of this study are used to determine the support of the scattering object together with an estimate of the material properties of the scatterer. This article introduces this new approach in inverse electromagnetic scattering theory, which is called the qualitative approach to inverse scattering theory.
Autors: Fioralba Cakoni;David Colton;Peter Monk;
Appeared in: IEEE Antennas and Propagation Magazine
Publication date: Oct 2017, volume: 59, issue:5, pages: 24 - 33
Publisher: IEEE
 
» Quality of Service for Wireless Network Implementation in Advanced Metering Infrastructure
Abstract:
The implementation of a robust communication system is essential for smart grids. This new system should provide an excellent quality of service (QoS) and a robust communication infrastructure, which must integrates the various devices on the network and its areas. This paper presents a study of the major network's needs, and describes the main applications of smart grids, and its QoS requirements. Some proposals in the literature are presented, and QoS needs in electrical grids are discussed. Because of its importance, the Advanced Metering Infrastructure (AMI) is evaluated and tested. The tests are made in an AMI with QoS implemented and also without QoS. The results indicate that the mechanisms and parameters for QoS in AMI are needed an also improving the messages speed.
Autors: Yona Lopes;Debora Cristina Muchaluat Saade;Celio Vinicius Neves de Albuquerque;Natalia Castro Fernandes;Marcio Zamboti Fortes;
Appeared in: IEEE Latin America Transactions
Publication date: Oct 2017, volume: 15, issue:10, pages: 1875 - 1880
Publisher: IEEE
 
» Quality-Aware Energy Optimization in Wireless Video Communication With Multipath TCP
Abstract:
The advancements in wireless communication technologies prompt the bandwidth aggregation for mobile video delivery over heterogeneous access networks. Multipath TCP (MPTCP) is the transport protocol recommended by IETF for concurrent data transmission to multihomed terminals. However, it still remains challenging to deliver user-satisfied video services with the existing MPTCP schemes because of the contradiction between energy consumption and received video quality in mobile devices. To enable the energy-efficient and quality-guaranteed video streaming, this paper presents an energy-distortion-aware MPTCP (EDAM) solution. First, we develop an analytical framework to characterize the energy-distortion tradeoff for multipath video transmission over heterogeneous wireless networks. Second, we propose a video flow rate allocation algorithm to minimize the energy consumption while achieving target video quality based on utility maximization theory. The performance of the proposed EDAM is evaluated through both experiments in real wireless networks and extensive emulations in exata. Experimental results show that EDAM exhibits performance advantages over existing MPTCP schemes in energy conservation and video quality.
Autors: Jiyan Wu;Bo Cheng;Ming Wang;Junliang Chen;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Oct 2017, volume: 25, issue:5, pages: 2701 - 2718
Publisher: IEEE
 
» Quantification of Arctic Soil and Permafrost Properties Using Ground-Penetrating Radar and Electrical Resistivity Tomography Datasets
Abstract:
Improving understanding of Arctic ecosystem climate feedback and parameterization of models that simulate freeze-thaw dynamics require advances in quantifying soil and snow properties. Due to the significant spatiotemporal variability of soil properties and the limited information provided by point-scale measurements (e.g., cores), geophysical methods hold potential for improving soil and permafrost characterization. In this study, we evaluate the use of a ground-penetrating radar (GPR) to estimate thaw layer thickness, snow depth, and ice-wedge characteristics in an ice-wedge-dominated tundra region near Barrow, AK, USA. To this end, we analyze GPR and point-scale measurements collected along several parallel transects at the end of the growing season and the end of frozen season. In addition, we compare the structural information extracted from the GPR data with electrical resistivity tomography (ERT) information about ice-wedge characteristics. Our study generally highlights the value of GPR data collected in the frozen season, when conditions lead to the improved GPR signal-to-noise ratio, facilitate data acquisition, and reduce acquisition-related ecosystem disturbance relative to growing season. We document for the first time that GPR data collected during the frozen season can provide reliable estimates of active layer thickness and geometry of ice wedges. We find that the ice-wedge geometry extracted from GPR data collected during the frozen season is consistent with ERT data, and that GPR data can be used to constrain the ERT inversion. Consistent with recent studies, we also find that GPR data collected during the frozen season can provide good estimates of snow thickness, and that GPR data collected during the growing season can provide reliable estimate thaw depth. Our quantification of the value of the GPR and ERT data collected during growing and frozen seasons paves the way for coupled inversion of the datasets to improve understanding of permafrost - ariability.
Autors: Emmanuel Léger;Baptiste Dafflon;Florian Soom;John Peterson;Craig Ulrich;Susan Hubbard;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Oct 2017, volume: 10, issue:10, pages: 4348 - 4359
Publisher: IEEE
 
» Quantification of Flow Electrification in the Context of a Tank Being Filled With a Dielectric Liquid
Abstract:
Contact of the walls of a tank with the liquid it is being filled with creates an electrical double layer of charge at the interface between the two materials, independently of their respective nature. On the liquid side, movement of this layer of electrical charge by the filling or draining of the tank induces a streaming current, which provides useful information concerning the intrinsic flow electrification phenomenon occurring near the tank walls. Indeed, the flow of the liquid modifies the electroneutrality of the solid/liquid interface, which is reestablished with the generation of a new electrical charge in the electrical double layer via complex physicochemical reactions in the form of a wall current. Moreover, this process of charge generation is modified if the liquid entering the tank already contains a certain amount of charge and may even invert the sign of the charge generated. This paper provides a detailed description of an experimental setup that allows measuring, the amount of charge entering with the liquid in a tank being filled and the intrinsic amount of charge generated at the wall of the tank independently of the charge coming with the liquid. These methods were validated by analytical models with an acceptable precision level for an industrial approach. Techniques for analyzing the impact of the charge entering the tank on the one generated intrinsically at the walls are also explored, but their validation is still under study.
Autors: Paul Daniel Stanley Clermont;Thierry Paillat;Gilles Peres;Yohann Duval;Gérard Touchard;Jean Rivenc;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4944 - 4949
Publisher: IEEE
 
» Quantifying Effects of Cutting and Welding on Magnetic Properties of Electrical Steels
Abstract:
The magnetic properties, namely the iron losses and the relative permeability, of SiFe electrical steel laminations after guillotine shearing and cutting by means of fiber and CO2 lasers are studied. The magnetic measurements are conducted on the Epstein frame for lamination strips with 1, 2, and 3 additional cutting edges along their length, in order to increase the cutting effect and the characterization data. The quantified effects of manufacturing (cutting and welding) are presented for three different material grades: M270-50A, M400-50A, and a nonoriented electrical steel of gauge 0.2 mm called NO20. Usage of the Epstein frame method allows any electrical steel company to reproduce the measurements for any specific grade. Data presented in normalized values facilitate utilization of the presented results and comparison between materials. An original model that incorporates the cutting effect considering homogenously damaged areas is developed and implemented in a finite-element method-based motor design software. Its originality is that it includes dependence on the geometry, included in the material magnetic properties. Simulations made for an industrial low voltage induction motor indicate a more than 15% increase in the iron losses compared with a model that does not consider the mechanical cutting effect. In the case of laser cutting, this increase reaches 30% to 50%, depending on laser settings. These relatively large increases of iron losses justify the implementation of the effect of cutting in industrial finite-element design tools, using a method that does not increase the simulation time.
Autors: Konstantinos Bourchas;Alexander Stening;Juliette Soulard;Arvid Broddefalk;Magnus Lindenmo;Mats Dahlén;Freddy Gyllensten;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4269 - 4278
Publisher: IEEE
 
» Quantifying Spatial and Angular Resolution of Light-Field 3-D Displays
Abstract:
Light-field 3-D displays are expected to play an important role as terminal devices, visualizing 3-D objects apparently floating in the air, or letting viewers see through a window with a scene behind it. Currently, there are neither methods nor practical tools to quantify light-field display's effective resolution or the perceived quality of the presented imagery. Most 3-D displays are simply characterized by the total number of pixels or light rays; however, this number does not properly characterize the distribution of the emitted light rays, or the level of detail that the display can visualize properly. This paper presents methods to measure the spatial (i.e., 2-D equivalent) and angular (i.e., directional) resolution of a given light-field display. The frequency-domain analysis of recorded test patterns gives the spatial resolution limit of the display under test, while angular resolution is determined by the display's ability to pass through patterns of uniform angle-dependent patterns. It also presents a subjective experiment to corroborate the objectively measured spatial resolution.
Autors: Péter Tamás Kovács;Robert Bregović;Atanas Boev;Attila Barsi;Atanas Gotchev;
Appeared in: IEEE Journal of Selected Topics in Signal Processing
Publication date: Oct 2017, volume: 11, issue:7, pages: 1213 - 1222
Publisher: IEEE
 
» Quantitative Assessment of Balance Impairment for Fall-Risk Estimation Using Wearable Triaxial Accelerometer
Abstract:
Falls are a major cause of morbidity and long-term hospitalization among growing older population. An automated and accurate fall-risk assessment system is vital to identify high fall-risk population and to prevent falls by early intervention. Therefore, this paper provides an objective, cost-effective, and unsupervised method to obtain functional balance and mobility assessment-based fall-risk of community-dwelling older adults. More specifically, waist-mounted triaxial accelerometer signals acquired from directed routine (supervised control movements) are used to estimate the well-known clinical assessment score-Berg balance scale (BBS). The trunk acceleration signals are used to extract features and to find the optimal subset of features for each training data during repeated tenfold cross validation of the BBS estimation model. The average of two BBS estimates based on test and retest yielded a strong correlation with the standard BBS score. Also, high correlation () and low root-mean-square error (1.66) was observed between the two estimates of each subject. The proposed method is well suited for the assessment of balance impairment and pre-screening of quantitative fall-risk in an unsupervised setting. It has the potential to act as a surrogate of the standard clinical assessment-BBS.
Autors: Ahsan Shahzad;Seunguk Ko;Samgyu Lee;Jeong-A Lee;Kiseon Kim;
Appeared in: IEEE Sensors Journal
Publication date: Oct 2017, volume: 17, issue:20, pages: 6743 - 6751
Publisher: IEEE
 
» Quasi-Periodicities Detection Using Phase-Rectified Signal Averaging in EEG Signals as a Depth of Anesthesia Monitor
Abstract:
Phase-rectified signal averaging (PRSA) has been known to be a useful method to detect periodicities in non-stationary biological signals. Determination of quasi-periodicities in electroencephalogram (EEG) is a candidate for quantifying the changes in the depth of anesthesia (DOA). In this paper, DOA monitoring capacity of periodicities detected using PRSA was quantified by assessing EEG signals collected from 56 patients during surgery. The method is compared with sample entropy (SampEn), detrended fluctuation analysis (DFA), and permutation entropy (PE). The performance of quasi-periodicities defined by deceleration capacity and acceleration capacity was tested using the area under the receiver operating characteristic curve (AUC) and Pearson correlation coefficient. During the surgery, a significant difference () in the quasi-periodicities was observed among three different stages under general anesthesia. There is a larger mean AUC and correlation coefficient of quasi-periodicities compared with SampEn, DFA, and PE using expert assessment of conscious level and bispectral index as the gold standard, respectively. Quasi-periodicities detected using PRSA in EEG signals are a powerful monitor of DOA and perform more accurate and robust results compared with SampEn, DFA, and PE. The results do provide a valuable reference to researchers in the field of clinical applications.
Autors: Quan Liu;Yi-Feng Chen;Shou-Zen Fan;Maysam F. Abbod;Jiann-Shing Shieh;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Oct 2017, volume: 25, issue:10, pages: 1773 - 1784
Publisher: IEEE
 
» Queueing Analysis of Unicast IPTV With Adaptive Modulation and Coding in Wireless Cellular Networks
Abstract:
Unicast Internet protocol television (IPTV) services that can support live TV, video-on-demand, video conferencing, and online gaming applications over broadband wireless cellular networks have been becoming popular for many years. However, video streaming services significantly impact the performance of wireless cellular networks because they are bandwidth hogs. To maintain the system performance, effective admission control and resource allocation mechanisms based on an accurate mathematical analysis are required. On the other hand, the quality of a wireless link usually changes with time because of user mobility or time-varying channel characteristics. To counteract such time-varying channels and improve the spectral efficiency, an adaptive modulation and coding (AMC) scheme is adopted in offering unicast IPTV services for mobile users. In this paper, closed-form solutions for the bandwidth usage, blocking rate, and dropping rate of unicast IPTV services over wireless cellular networks were derived based on the novel queueing model that considers AMC. Simulations were also conducted to validate the accuracy of analytical results. Numerical results demonstrate that the presented analytical results are accurate. Based on the accurate closed-form solutions, network providers can implement precise admission control and resource allocation for their networks to enhance the system performance.
Autors: Mingfu Li;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 9241 - 9253
Publisher: IEEE
 
» Radar Sounding Through the Earth’s Ionosphere at 45 MHz
Abstract:
Radar sounding from aircraft or ground-coupled radars has long provided scientists with a powerful technique to sound through ice layers to retrieve local depth and layering structure. More recently, it has been used to detect shallow aquifers in warm, dry, and desert regions. At Mars, a long-wavelength radar sounding from low orbit altitudes has produced global maps that reveal the presence of ice layering at all latitudes and glacial deposits on the flanks of volcanoes. Until now, sounding from the earth orbit at wavelengths long enough to penetrate ice sheets and arid sand was thought to be infeasible, because of the electromagnetic properties of the ionosphere. In this paper, we show that a radar sounding at frequencies as low as 45 MHz is, in fact, theoretically possible under viewing conditions that occur often enough to be practical. This conclusion opens up a previously unutilized portion of the electromagnetic spectrum for large-scale, spaceborne remote sensing of subsurface features on the earth.
Autors: Anthony Freeman;Xiaoqing Pi;Essam Heggy;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5833 - 5842
Publisher: IEEE
 
» RadioBio [Microwave Surfing]
Abstract:
The paper presents the purposeful signaling via electromagnetic waves” exist at the cellular level in biosystems. DARPA-funded studies will be exploring electromagnetic behavior at the cellular level, many scientists are already doing intriguing work at the interface of biology and electronics.
Autors: Rajeev Bansal;
Appeared in: IEEE Microwave Magazine
Publication date: Oct 2017, volume: 18, issue:6, pages: 16 - 18
Publisher: IEEE
 
» Range-Recursive IAA for Scanning Radar Angular Super-Resolution
Abstract:
Recently, the iterative adaptive approach (IAA) was adopted to allow for the estimation of high-resolution scanning radar images. In this letter, we further develop this approach by introducing a range-recursive IAA (IAA-RR) formulation allowing for a computationally efficient updating of the resulting estimates along range. Besides exploiting the rich matrix structure to mitigate the computational complexity for each iteration, the correlation between adjacent range cells is exploited to accelerate the convergence of the IAA iterations. When an additional range measurement becomes available, further acceleration is available by exploiting the estimates already formed for the adjacent range cells. Compared with the existing fast IAA implementation, the proposed IAA-RR is shown to offer significant computational savings, without noticeable loss in performance. Numerical results illustrate the superior performance of the proposed IAA-RR algorithm.
Autors: Yongchao Zhang;Andreas Jakobsson;Jianyu Yang;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1675 - 1679
Publisher: IEEE
 
» Rapid Line-Extraction Method for SAR Images Based on Edge-Field Features
Abstract:
This letter proposes a rapid line-extraction (RLE) method for synthetic aperture radar (SAR) images. RLE first transforms an image in the space domain into an image in the frequency domain. Then, using the central-slice theorem, RLE skilfully maps the image in the frequency domain into a parameter space, which effectively accelerates the straight-line extraction process. Unlike the traditional Hough transform, RLE is performed directly on an edge-field image rather than on a binary edge map. Theoretical analysis proves the advantages of using the edge-field map. Notably, the computational complexity can be greatly reduced relative to the complexity of obtaining a binary edge map, and the method can efficiently avoid the negative influence of false edges in the binary edge map. More importantly, because speckle, clutter, and blurred edges in real-world images decrease the sharpness of peaks, edge-field images that include the strength and direction information of SAR images are adopted to reduce the diffusion of peaks and improve the detection accuracy. Experimental studies show that RLE works independently, is robust to noise, has low computational complexity, achieves high true-positive detection rates, and yields satisfactory detection precision.
Autors: Qian-Ru Wei;Da-Zheng Feng;Wei Zheng;Jiang-Bin Zheng;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1865 - 1869
Publisher: IEEE
 
» Rapid MPPT for Uniformly and Partial Shaded PV System by Using JayaDE Algorithm in Highly Fluctuating Atmospheric Conditions
Abstract:
In photovoltaic (PV) array, the output power and the power–voltage (PV ) characteristic of PV array are totally dependent on the temperature and solar insolation. Therefore, if these atmospheric parameters fluctuate rapidly, then the maximum power point (MPP) of the P–V curve of PV array also fluctuates very rapidly. This rapid fluctuation of the MPP may be in accordance with the uniform shading of the PV panel or may be in accordance to the partially shaded due to the clouds, tall building, trees, and raindrops. However, in both cases, the MPP tracking (MPPT) is not only a nonlinear problem, this becomes a highly nonlinear problem, which solution is time bounded. Because the highly fluctuating atmospheric conditions change the P–V characteristic after every small time duration. This paper introduces a hybrid of “Jaya” and “differential evolution (DE)” (JayaDE) technique for MPPT in the highly fluctuating atmospheric conditions. This JayaDE algorithm is tested on MATLAB simulator and is verified on a developed hardware of the solar PV system, which consists of a single peak and many multiple peaks in the voltage–power curve. Moreover, the tracking ability is compared with the recent state of the art methods. The satisfactory steady-state and dynamic performances of this new hybrid technique under variable irradiance and temperature levels show the superiority over the state-of-the-art control methods.
Autors: Nishant Kumar;Ikhlaq Hussain;Bhim Singh;Bijaya Ketan Panigrahi;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2406 - 2416
Publisher: IEEE
 
» Raptor Code-Enabled Reliable Data Transmission for In-Vehicle Power Line Communication Systems With Impulsive Noise
Abstract:
With the rapid development of in-vehicle data transmission systems, the power line communication (PLC) technology is considered as a good alternative due to the reduction of cable harness. However, PLC suffers from severe impulse noise, which hinders the correct reception of data packets, and hence, leads to a poor transmission performance. In this letter, we propose a raptor code-enabled data transmission scheme for different traffic classes in in-vehicle PLC systems. Simulation results show that the proposed scheme is suitable for in-vehicle data transmission and can provide good protection against the impulsive noise, while a considerable reception overhead is needed.
Autors: Zhaopeng Xu;Chuanchuan Yang;Zhongwei Tan;Zhengguo Sheng;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2154 - 2157
Publisher: IEEE
 
» Real-Time Assessment of Mechanical Tissue Trauma in Surgery
Abstract:
Objective: This work presents a method to assess and prevent tissue trauma in real-time during surgery. Background: Tissue trauma occurs routinely during laparoscopic surgery with potentially severe consequences. As such, it is crucial that a surgeon is able to regulate the pressure exerted by surgical instruments. We propose a novel method to assess the onset of tissue trauma by considering the mechanical response of tissue as it is loaded in real-time. Methods: We conducted a parametric study using a lab-based grasping model and differing load conditions. Mechanical stress-time data were analyzed to characterize the tissue response to grasps. Qualitative and quantitative histological analyses were performed to inspect damage characteristics of the tissue under different load conditions. These were correlated against the mechanical measures to identify the nature of trauma onset with respect to our predictive metric. Results: Results showed increasing tissue trauma with load and a strong correlation with the mechanical response of the tissue. Load rate and load history also showed a clear effect on tissue response. The proposed method for trauma assessment was effective in identifying damage. The metric can be normalized with respect to loading rate and history, making it feasible in the unconstrained environment of intraoperative surgery. Significance: This work demonstrates that tissue trauma can be predicted using mechanical measures in real-time. Applying this technique to laparoscopic tools has the potential to reduce unnecessary tissue trauma and its associated complications by indicating through user feedback or actively regulating the mechanical impact of surgical instruments.
Autors: James H. Chandler;Faisal Mushtaq;Benjamin Moxley-Wyles;Nicholas P. West;Gregory W. Taylor;Peter R. Culmer;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Oct 2017, volume: 64, issue:10, pages: 2384 - 2393
Publisher: IEEE
 
» Real-time Detection System of Electrical Disturbances for Remote Communication Stations and Smart Grid
Abstract:
This article proposes the development of a disturbance detection system in the electrical network that operates in real time. The system is employed in RCS (remote communication stations), registering electrical disturbances for network monitoring. Notifications are delivered to the power distribution company autonomously, promoting integration of remote communication stations with the concept of Smart Grid. The developed system differs from others by using a method based on euclidean distance for the disturbances detection. Moreover, a web interface is offered for monitoring via Ethernet. Our system uses an Arduino platform for signal processing, sensors to obtain data and Ethernet and GSM network interfaces for communication. Using diverse communication technologies promotes redundancy in communication and notification to the power distribution company. The system was able to detect efficiently most of assessed voltage disturbances. It was also able to send monitoring events using the private network of the RCS and also employing SMS notification messages.
Autors: Wesley Natanael Gallo;Tales Heimfarth;Danton Diego Ferreira;Thais Martins Mendes;
Appeared in: IEEE Latin America Transactions
Publication date: Oct 2017, volume: 15, issue:10, pages: 1894 - 1900
Publisher: IEEE
 
» Real-Time Enhancement of Dynamic Depth Videos with Non-Rigid Deformations
Abstract:
We propose a novel approach for enhancing depth videos containing non-rigidly deforming objects. Depth sensors are capable of capturing depth maps in real-time but suffer from high noise levels and low spatial resolutions. While solutions for reconstructing 3D details in static scenes, or scenes with rigid global motions have been recently proposed, handling unconstrained non-rigid deformations in relative complex scenes remains a challenge. Our solution consists in a recursive dynamic multi-frame superresolution algorithm where the relative local 3D motions between consecutive frames are directly accounted for. We rely on the assumption that these 3D motions can be decoupled into lateral motions and radial displacements. This allows to perform a simple local per-pixel tracking where both depth measurements and deformations are dynamically optimized. The geometric smoothness is subsequently added using a multi-level L1 minimization with a bilateral total variation regularization. The performance of this method is thoroughly evaluated on both real and synthetic data. As compared to alternative approaches, the results show a clear improvement in reconstruction accuracy and in robustness to noise, to relative large non-rigid deformations, and to topological changes. Moreover, the proposed approach, implemented on a CPU, is shown to be computationally efficient and working in real-time.
Autors: Kassem Al Ismaeil;Djamila Aouada;Thomas Solignac;Bruno Mirbach;Björn Ottersten;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Oct 2017, volume: 39, issue:10, pages: 2045 - 2059
Publisher: IEEE
 
» Real-Time Experimental Measurement of Swept Source VCSEL Properties Relevant to OCT Imaging
Abstract:
A real-time study of the dynamic properties of a frequency swept vertical cavity surface emitting laser (VCSEL) is presented. Such tunable laser sources have previously been shown to provide long coherence lengths and improved performance in metrology and imaging applications. Single-shot interferometric reconstruction of both the phase and intensity of the swept source allows for experimental measurement of the full complex electric field over multiple sweep periods. Access to the electric field enables direct measurement of laser properties that can be related to the imaging performance of the laser when used in a swept source optical coherence tomography application. Both inter-sweep and intra-sweep characterization is possible, including determination of the instantaneous spectral shape, sweep rate, linewidth, coherence roll-off, and point spread function.
Autors: T. P. Butler;S. Slepneva;P. M. McNamara;K. Neuhaus;D. Goulding;M. Leahy;G. Huyet;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 10
Publisher: IEEE
 
» Real-Time GPU-Based Image Processing for a 3-D THz Radar
Abstract:
A real-time image processing algorithm, using a GPU with NVIDIA’s CUDA technology, for a 3-D through-clothes detection radar in the THz band has been developed. Traditional CPU-based architectures lack the computing power and parallelization needed to meet the image refresh rates imposed by the radar’s scanning. This solution presents a low-cost and flexible alternative that allows image refresh at a rate of more than 8 fps for images composed of 6,000 pixels, corresponding to a scanned area of 5090 cm . The performance of this code has been profiled, with comparison against a previous CPU-executed version, and some optimizations that would enable even faster refresh have been analyzed.
Autors: Federico García-Rial;Luis Úbeda-Medina;Jesús Grajal;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Oct 2017, volume: 28, issue:10, pages: 2953 - 2964
Publisher: IEEE
 
» Real-time video transmission over different underwater wireless optical channels using a directly modulated 520 nm laser diode
Abstract:
We experimentally demonstrate high-quality real-time video streaming over an underwater wireless optical communication (UWOC) link up to 5 m distance using phase-shift keying (PSK) modulation and quadrature amplitude modulation (QAM) schemes. The communication system uses software defined platforms connected to a commercial TO-9 packaged pigtailed 520 nm directly modulated laser diode (LD) with 1.2 GHz bandwidth as the optical transmitter and an avalanche photodiode (APD) module as the receiver. To simulate various underwater channels, we perform laboratory experiments on clear, coastal, harbor I, and harbor II ocean water types. The measured bit error rates of the received video streams are 1.0 × 10-9 for QPSK, 4-QAM, and 8-QAM and 9.9 × 10-9 for 8-PSK. We further evaluate the quality of the received live video images using structural similarity and achieve values of about 0.9 for the first three water types, and about 0.7 for harbor II. To the best of our knowledge, these results present the highest quality video streaming ever achieved in UWOC systems that resemble communication channels in real ocean water environments.
Autors: Abdullah Al-Halafi;Hassan Makine Oubei;Boon S. Ooi;Basem Shihada;
Appeared in: IEEE/OSA Journal of Optical Communications and Networking
Publication date: Oct 2017, volume: 9, issue:10, pages: 826 - 832
Publisher: IEEE
 
» Realization of a Diamagnetically Levitating Rotor Driven by Electrostatic Field
Abstract:
In this paper, a novel configuration of frictionless diamagnetic levitation combined with electrostatic glass motor is presented. A 12.5  mm diameter disc shaped rotor comprised of pyrolytic graphite and glass is fabricated. The rotor disc is levitated stably by the diamagnetic field in five degrees of freedom and driven by the rotating electrostatic field. It is the first time that the combination of both functions is realized. The main advantages of the proposed novel system are noncontact levitation, low energy consumption, and simplicity, which may find promising applications in the fields of spacecraft attitude control (micro gyroscope) or ultrahigh vacuum environment technology (optical trap etc.).
Autors: Yuanping Xu;Qingwen Cui;Ryosuke Kan;Hannes Bleuler;Jin Zhou;
Appeared in: IEEE/ASME Transactions on Mechatronics
Publication date: Oct 2017, volume: 22, issue:5, pages: 2387 - 2391
Publisher: IEEE
 
» Realizing Fully Digital Precoders in Hybrid A/D Architecture With Minimum Number of RF Chains
Abstract:
In this letter, the minimum number of required radio frequency (RF) chains for realizing any MIMO fully digital precoder (FDP) with the hybrid analog/digital precoder (HADP) architecture is investigated from a new perspective. First, in order to take full advantage of the digital domain, an extended system formulation of the hybrid structure is presented in which the digital precoder is taken from an abstract transformation space. Then, a constrained optimization problem is formulated, where the aim is to minimize the number of RF chains subject to an equality constraint on the multi-stream FDP and HADP outputs. We show that non-unique optimum solutions exist for only two RF chains. Based on these results, we further develop a single RF chain design. The implementation of the latter does not require extra hardware or computational complexity. We compare the proposed HADP design with recent works that require larger number of RF chains and demonstrate that significant improvement in performance can be achieved over direct HADP design.
Autors: Alireza Morsali;Afshin Haghighat;Benoit Champagne;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2310 - 2313
Publisher: IEEE
 
» REAPER: Reprocessing 12 Years of ERS-1 and ERS-2 Altimeters and Microwave Radiometer Data
Abstract:
Twelve years (1991–2003) of ERS-1 and ERS-2 altimetry data have been reprocessed within the European Space Agency (ESA) reprocessing altimeter products for ERS (REAPER) project using an updated, modern set of algorithms and auxiliary models. The reprocessed data set (identified as RP01) has been cross-calibrated against the reprocessed ENVISAT V2.1 data. The format of this reprocessed data set is network common data form (version 3). The new data set shows a clear improvement in data quality beyond that of previous releases. The product validation shows reduction of the mean standard deviation of the sea-surface height differences from 8.1 (previously available product) to 6.7 cm (RP01). This paper presents the details of how the reprocessing was conducted and shows selected results from the validation and quality-assurance processes. The major improvements of the REAPER RP01 data set with respect to the previous ESA ERS radar altimetry (RA) products are due to the use of four ENVISAT RA-2 retrackers, RA calibration improvements, new reprocessed precise orbit solutions, ECMWF ERA-interim model for meteorological corrections, new ionospheric corrections, and new sea state. The intent of this paper is to aid the reader in understanding the benefits of the new data set for their particular use-case.
Autors: David J. Brockley;Steven Baker;Pierre Féménias;Bernat Martínez;Franz-Heinrich Massmann;Michiel Otten;Frédéric Paul;Bruno Picard;Pierre Prandi;Mònica Roca;Sergei Rudenko;Remko Scharroo;Pieter Visser;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5506 - 5514
Publisher: IEEE
 
» Rebuttal to “On Dual-Band Amplifications Using Dual Two-Tones: Clarifications and Discussions”
Abstract:
This rebuttal is to “On dual-band amplifications using dual two-tone: Clarifications and discussion.” In the following, we provide our reply.
Autors: Shoaib Amin;Wendy van Moer;Peter Händel;Daniel Rönnow;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Oct 2017, volume: 66, issue:10, pages: 2795 - 2797
Publisher: IEEE
 
» Recent Improvements to Suomi NPP Ozone Mapper Profiler Suite Nadir Mapper Sensor Data Records
Abstract:
The Ozone Mapping and Profiler Suite (OMPS) is carried onboard on the Suomi National Polar-orbiting Partnership satellite which was launched on October 28, 2011. Since its launch, many changes in radiometric and spectrometric calibration have been made to improve the OMPS sensor data quality. The most challenging issue is to correct an unexpected variation of the in-flight wavelength scale in the OMPS Nadir Mapper (NM) spectrometer. Validation of the NM earth viewing albedo estimates of 2% to 5% wavelength-dependent errors across the sensor spatial instantaneous field of views (IFOVs). The root cause attributes these errors to a large variation in the wavelength registration for each of the NM charge-coupled device earth view pixels. Recent calibration change has significantly improved the total wavelength knowledge accuracy, and as a result the NM wavelength-dependent albedo uncertainty is reduced below the requirement of 2% for most of the channels across all of the spatial IFOVs.
Autors: Chunhui Pan;Fuzhong Weng;T. Beck;L. Flynn;Shouguo Ding;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5770 - 5776
Publisher: IEEE
 
» Reciprocating Geared Mechanism with Compliant Suspension
Abstract:
We present a novel cycloidal geared mechanism with a continuous rotational input featuring a reciprocating translational output. A statically balanced compliant mechanism suspends an annulus driven by a cycloidal rotor. The freedom and constraint topology design method is used to synthesize the compliant suspension. A fixed transmission ratio of 15 results from the ratio between the cycloidal rotor and the annulus. The static balancing conditions of the suspension are developed analytically, and validated using finite-element modeling and experimental results. Moreover, the estimation of the frictional loss as a function of the stiffness of the compliant members is derived using a force analysis of the system and verified using experimental data. A case study on a mechanical watch yields dimensions for the prototype, which is fabricated in silicon using deep reactive ion etching. Experiments show that energy loss as a function of the stiffness of compliant members is marginal and independent of the position of the compliant suspension. [2016-0260]
Autors: Jan Wessels;Davood Farhadi Machekposhti;Just L. Herder;Guy Sèmon;Nima Tolou;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Oct 2017, volume: 26, issue:5, pages: 1047 - 1054
Publisher: IEEE
 
» Reconstruction of Dispersion Curves in the Frequency-Wavenumber Domain Using Compressed Sensing on a Random Array
Abstract:
In underwater acoustics, shallow-water environments act as modal dispersive waveguides when considering low-frequency sources, and propagation can be described by modal theory. In this context, propagated signals are composed of few modal components, each of them propagating according to its own wavenumber. Frequency-wavenumber representations are classical methods allowing modal separation. However, they require large horizontal line sensor arrays aligned with the source. In this paper, to reduce the number of sensors, a sparse model is proposed and combined with prior knowledge on the wavenumber physics. The method resorts to a state-of-the-art Bayesian algorithm exploiting a Bernoulli–Gaussian model. The latter, well suited to the sparse representations, makes possible a natural integration of prior information through a wise choice of the Bernoulli parameters. The performance of the method is quantified on simulated data and finally assessed through a successful application on real data.
Autors: Angélique Drémeau;Florent Le Courtois;Julien Bonnel;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Oct 2017, volume: 42, issue:4, pages: 914 - 922
Publisher: IEEE
 
» Recovery of Damped Exponentials Using Structured Low Rank Matrix Completion
Abstract:
We introduce a structured low rank matrix completion algorithm to recover a series of images from their under-sampled measurements, where the signal along the parameter dimension at every pixel is described by a linear combination of exponentials. We exploit the exponential behavior of the signal at every pixel, along with the spatial smoothness of the exponential parameters to derive an annihilation relation in the Fourier domain. This relation translates to a low-rank property on a structured matrix constructed from the Fourier samples. We enforce the low-rank property of the structured matrix as a regularization prior to recover the images. Since the direct use of current low rank matrix recovery schemes to this problem is associated with high computational complexity and memory demand, we adopt an iterative re-weighted least squares algorithm, which facilitates the exploitation of the convolutional structure of the matrix. Novel approximations involving 2-D fast Fourier transforms are introduced to drastically reduce the memory demand and computational complexity, which facilitates the extension of structured low-rank methods to large scale 3-D problems. We demonstrate our algorithm in the MR parameter mapping setting and show improvement over the state-of-the-art methods.
Autors: Arvind Balachandrasekaran;Vincent Magnotta;Mathews Jacob;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Oct 2017, volume: 36, issue:10, pages: 2087 - 2098
Publisher: IEEE
 
» Reduced Basis Finite Element Modeling of Electrical Machines with Multiconductor Windings
Abstract:
Finite element (FE) analysis of electrical machines with multiconductor windings can be computationally costly. This paper proposes a solution to this problem, using a reduced basis approach. The field-circuit problem is first solved in a single slot only with a set of different boundary conditions. These precomputed solutions are then used as shape functions to approximate the solution in all slots of the full problem. A polynomial interpolation method is also proposed for coupling the slot domains with the rest of the geometry, even if the geometries or meshes do not fully conform on the boundary. The method is evaluated on several test problems both in the frequency and time domains. According to the simulations, accurate solutions are obtained, 54–90 times faster as compared with the established FE approach.
Autors: Antti Lehikoinen;Antero Arkkio;Anouar Belahcen;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4252 - 4259
Publisher: IEEE
 
» Reducing Arc-Flash Hazards: Installing MV-Controllable Fuses on the Secondary Side of the Transformer in a Pumped Storage Plant
Abstract:
The Mitigation of arc-flash incident energy is important to increase safety. One method is to reduce the duration of the arc flash by using protective relays to sense an arc-flash fault. This method requires a supply-side switching device that will respond to the protective relaying fast enough to mitigate the incident energy. In many existing installations, medium-voltage (MV) controllable fuses are already installed to provide transformer protection. Before the development of an MV-controllable fuse, the MV fuse would have to be replaced with an MV circuit breaker or circuit switcher to have relay control of the MV protective device. This replacement would have significant equipment and construction costs and require extensive equipment outage time. The MV-controllable-fuse method uses the existing fusegear protecting the primary side of the transformer. The protective relay senses the arc fault and signals the controllable fuse to change to a fasteracting time-current response. The incident energies can be reduced from 200 cal/cm2 to lower than 8 cal/cm2 on the secondary side of the transformer. This article reviews an installation using an MV-controllable fuse to mitigate the incident energy on the equipment connected to the secondary side of the transformer.
Autors: Peter R. Walsh;Michael M. Price;
Appeared in: IEEE Industry Applications Magazine
Publication date: Oct 2017, volume: 23, issue:5, pages: 21 - 27
Publisher: IEEE
 
» Reducing Critical Configuration Bits via Partial TMR for SEU Mitigation in FPGAs
Abstract:
This paper represents an single-event upset (SEU) hardened scheme for hardening circuits mapped onto field-programmable gate arrays (FPGAs). The proposed scheme calculates failure probability based on critical FPGA configuration bits and performs placement and routing to reduce the failure probability as much as possible. If the calculated failure probability is still greater than the required failure rate, partial triple modular redundancy is implemented to reduce critical configuration bits until the calculated failure probability is less than the required failure rate. The proposed scheme reduces area and power overhead and improves SEU vulnerability when compared with some previous schemes.
Autors: Xiaoxuan She;N. Li;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Oct 2017, volume: 64, issue:10, pages: 2626 - 2632
Publisher: IEEE
 
» Reducing Energy Waste Due to Idle Network Devices
Abstract:
The original NCP concept was introduced in the literature with two objectives: 1) impersonate basic network presence (i.e., ARP, PING) and maintain reachability (i.e., WoC) and 2) impersonate Internet-based applications and their associated TCP connections. The first objective faces no serious issues and is practically realizable. The second objective is very challenging and prohibits the development of a full-fledged NCP prototype (i.e., proxying proprietary closed-source applications). To overcome the limitations of the NCP concept, we proposed a system that uses a very lightweight gateway proxy that impersonates ARP and ping protocols on behalf of sleeping devices and wakes them up when necessary (e.g., remote access). Instead of proxying applications and TCP sessions, this system ensures that applications run on a single-user device at any given time. These applications will run on a smartphone, tablet, laptop, or desktop PC based on user-specified configurations and devices priorities. The proposed system is nearly realizable, and the achievable energy savings are equivalent or higher than the original NCP concept. Furthermore, it is also beneficial for mobile devices by improving their battery life due to not running applications 24/7.
Autors: Rafiullah Khan;Sarmad Ullah Khan;
Appeared in: IEEE Potentials
Publication date: Oct 2017, volume: 36, issue:5, pages: 37 - 45
Publisher: IEEE
 
» Reducing Image Compression Artifacts by Structural Sparse Representation and Quantization Constraint Prior
Abstract:
The block discrete cosine transform (BDCT) has been widely used in current image and video coding standards, owing to its good energy compaction and decorrelation properties. However, because of independent quantization of DCT coefficients in each block, BDCT usually gives rise to visually annoying blocking compression artifacts, especially at low bit rates. In this paper, to reduce blocking artifacts and obtain high-quality images, image deblocking is cast as an optimization problem within maximum a posteriori framework, and a novel algorithm for image deblocking by using structural sparse representation (SSR) prior and quantization constraint (QC) prior is proposed. The SSR prior is utilized to simultaneously enforce the intrinsic local sparsity and the nonlocal self-similarity of natural images, while QC is explicitly incorporated to ensure a more reliable and robust estimation. A new split Bregman iteration-based method with an adaptively adjusted regularization parameter is developed to solve the proposed optimization problem, which makes the entire algorithm more practical. Experiments demonstrate that the proposed image-deblocking algorithm combining SSR and QC outperforms the current state-of-the-art methods in both peak signal-to-noise ratio and visual perception.
Autors: Chen Zhao;Jian Zhang;Siwei Ma;Xiaopeng Fan;Yongbing Zhang;Wen Gao;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Oct 2017, volume: 27, issue:10, pages: 2057 - 2071
Publisher: IEEE
 
» Reducing Uncertainty of Probabilistic Top-$k$ Ranking via Pairwise Crowdsourcing
Abstract:
Probabilistic top- ranking is an important and well-studied query operator in uncertain databases. However, the quality of top- results might be heavily affected by the ambiguity and uncertainty of the underlying data. Uncertainty reduction techniques have been proposed to improve the quality of top- results by cleaning the original data. Unfortunately, most data cleaning models aim to probe the exact values of the objects individually and therefore do not work well for subjective data types, such as user ratings, which are inherently probabilistic. In this paper, we propose a novel pairwise crowdsourcing model to reduce the uncertainty of top- ranking using a crowd of domain experts. Given a crowdsourcing task of limited budget, we propose efficient algorithms to select the best object pairs for crowdsourcing that will bring in the highest quality improvement. Extensive experiments show that our proposed solutions outperform a random selection method by up to 30 times in terms of quality improvement of probabilistic top- ranking queries. In terms of efficiency, our proposed solutions can reduce the elapsed time of a brute-force algorithm from several days to one minute.
Autors: Xin Lin;Jianliang Xu;Haibo Hu;Zhe Fan;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Oct 2017, volume: 29, issue:10, pages: 2290 - 2303
Publisher: IEEE
 
» Reduction of Second-Order Network Systems With Structure Preservation
Abstract:
This paper proposes a general framework for structure-preserving model reduction of a second-order network system based on graph clustering. In this approach, vertex dynamics are captured by the transfer functions from inputs to individual states, and the dissimilarities of vertices are quantified by the -norms of the transfer function discrepancies. A greedy hierarchical clustering algorithm is proposed to place those vertices with similar dynamics into same clusters. Then, the reduced-order model is generated by the Petrov–Galerkin method, where the projection is formed by the characteristic matrix of the resulting network clustering. It is shown that the simplified system preserves an interconnection structure, i.e., it can be again interpreted as a second-order system evolving over a reduced graph. Furthermore, this paper generalizes the definition of network controllability Gramian to second-order network systems. Based on it, we develop an efficient method to compute -norms and derive the approximation error between the full-order and reduced-order models. Finally, the approach is illustrated by the example of a small-world network.
Autors: Xiaodong Cheng;Yu Kawano;Jacquelien M. A. Scherpen;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5026 - 5038
Publisher: IEEE
 
» Reflections on the Life of William F. Croswell [In Memoriam]
Abstract:
Recounts the career and contributions of William F. Croswell.
Autors: Joseph W. Crosswell;Calvin T. Smith;
Appeared in: IEEE Antennas and Propagation Magazine
Publication date: Oct 2017, volume: 59, issue:5, pages: 173 - 175
Publisher: IEEE
 
» Regular Hilberg Processes: An Example of Processes With a Vanishing Entropy Rate
Abstract:
A regular Hilberg process is a stationary process that satisfies both a hyperlogarithmic growth of maximal repetition and a power-law growth of topological entropy, which are a kind of dual conditions. The hyperlogarithmic growth of maximal repetition has been experimentally observed for texts in natural language, whereas the power-law growth of topological entropy implies a vanishing Shannon entropy rate and thus probably does not hold for natural language. In this paper, we provide a constructive example of regular Hilberg processes, which we call random hierarchical association (RHA) processes. Our construction does not apply the standard cutting and stacking method. For the constructed RHA processes, we demonstrate that the expected length of any uniquely decodable code is the orders of magnitude larger than the Shannon block entropy of the ergodic component of the RHA process. Our proposition supplements the classical result by Shields concerning nonexistence of universal redundancy rates.
Autors: Łukasz Dębowski;
Appeared in: IEEE Transactions on Information Theory
Publication date: Oct 2017, volume: 63, issue:10, pages: 6538 - 6546
Publisher: IEEE
 
» Regularized Difference Criterion for Computing Discriminants for Dimensionality Reduction
Abstract:
Hyperspectral data classification has shown potential in many applications. However, a large number of spectral bands cause overfitting. Methods for reducing spectral bands, e.g., linear discriminant analysis, require matrix inversion. We propose a semidefinite programming for linear discriminants regularized difference (SLRD) criterion approach that does not require matrix inversion. The paper establishes a classification error bound and provides experimental results with ten methods over six hyperspectral datasets demonstrating the efficacy of the proposed SLRD technique.
Autors: Alex J. Aved;Erik P. Blasch;Jing Peng;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Oct 2017, volume: 53, issue:5, pages: 2372 - 2384
Publisher: IEEE
 
» Relationship Between Vegetation Microwave Optical Depth and Cross-Polarized Backscatter From Multiyear Aquarius Observations
Abstract:
Soil moisture retrieval algorithms based on passive microwave remote sensing observations need to account for vegetation attenuation and emission, which is generally parameterized as vegetation optical depth (VOD). This multisensor study tests a new method to retrieve VOD from cross-polarized radar backscattering coefficients. Three years of Aquarius/SAC-D data were used to establish a relationship between the cross-polarized backscattering coefficient σHV and VOD derived from a multitemporal passive dual-channel algorithm (VODMT). The dependence of the correspondence is analyzed for different land use classes. There are no systematic differences in the slope for woody versus nonwoody vegetation, resulting in a strong correlation (80% explained-variance) and a global linear relationship when all classes are combined. The relationship is stable over the years of observations. The comparison of the Aquarius-derived VODMT to Soil Moisture and Ocean Salinity's multi-angular VOD estimates shows similar spatial patterns and temporal behavior, evident in high correlations. However, VODMT has considerably higher mean values, but lower dynamic range globally. Most of the differences can be attributed to differences in instrument sampling. The main result of this study, a relationship between backscatter and VOD, will permit high-resolution mapping of VOD with synthetic aperture radar measurements. These maps allow future studies of scaling and heterogeneity effects of vegetation on soil moisture retrieval at the coarser scales of land microwave radiometry. The study shows that VOD based on passive measurements and predicted by active measurements are comparable globally and that the breakdown by land cover classification does not affect the relationship appreciably.
Autors: Kathrina Rötzer;Carsten Montzka;Dara Entekhabi;Alexandra G. Konings;Kaighin A. McColl;Maria Piles;Harry Vereecken;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Oct 2017, volume: 10, issue:10, pages: 4493 - 4503
Publisher: IEEE
 
» Relative Importance of Bottom Attenuation and Scattering in the Shallow-Water TREX13 Environment
Abstract:
In this paper, the results of applying normal mode models to explain measured data collected during the 2013 Target and Reverberation Experiment (TREX13) are presented. An adiabatic, and one-way coupled, Born approximation normal mode model (Nautreverb) and an energy conserving two-way coupled mode model (Aeneid) are described. Both monostatic and bistatic reverberation time series solutions are produced with the models for a rough bottom spectrum or a realization from it. Next, monostatic reverberation time series are produced, for both the Nautreverb and Aeneid models, with the measured bottom roughness parameter values obtained from measurements made during TREX13. In addition, loss mechanisms for depth averaged transmission loss are assessed. The relative effects of bottom attenuation and loss due to scattering, for several variants of the model parameters for the TREX13 environment, are also discussed. Based on the small roughness measured at the TREX13 site, bottom attenuation appears to be the dominant loss mechanism. Adjustments of the frequency dependence of the bottom attenuation were constructed to reproduce salient features of the measured transmission loss.
Autors: Steven A. Stotts;Robert A. Koch;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Oct 2017, volume: 42, issue:4, pages: 1125 - 1134
Publisher: IEEE
 
» Relaxation of Ferromagnetic and Paramagnetic State of Thin La-Sr-MnO Films Exposed by High-Power Picosecond Duration Optical Pulses
Abstract:
We have investigated resistivity rise and relaxation of thin epitaxial (EP) and nanostructured polycrystalline (NP) La-Sr-MnO films after thermal shock. Samples of 400-nm thickness La0.83Sr0.17MnO3 were grown on LaAlO3 substrate for EP films, and on “lucalox” for NP films. The thermal shocks were induced by 1064-nm 30-ps Nd:YAG laser pulses with pulse energy at the sample between 1.5 and 2 mJ. Samples were treated by single laser pulse at different ambient temperatures when the film was in ferromagnetic or paramagnetic state. In the films at temperatures ( lower than phase transition temperature ( immediately after the laser pulse, the resistance of the sample has increased. It was found that the rise time of resistance response increases with increase of in the range from few hundred ps to several ns. Meanwhile, the time of total relaxation of resistance back to initial level was in the range from 10 to 35 . For both types of films, the experimental results of cooling process showed longer relaxation time than that of obtained in theoretical modeling. Possible reasons were discussed taking into account magnetic ordering processes. The obtained results help to evaluate the influence of fast temperature changes during high pulsed magnetic field measurements with B-scalar sensors based on La-Sr-MnO films.
Autors: Saulius Balevičius;Skirmantas Keršulis;Mykolas Mališauskas;Jonas Klimantavičius;Voitech Stankevič;Nerija Žurauskienė;Valentina Plaušinaitienė;Zigmas Balevičius;Karolis Požel
Appeared in: IEEE Transactions on Plasma Science
Publication date: Oct 2017, volume: 45, issue:10, pages: 2794 - 2799
Publisher: IEEE
 
» Reliability Enhancement of Redundancy Management in AFDX Networks
Abstract:
Avionics Full Duplex Switched Ethernet is a safety critical network in which a redundancy management mechanism is employed to enhance the reliability of the network. However, as stated in the ARINC664-P7 standard, there still exists a potential problem, which may fail redundant transmissions due to sequence inversion in the redundant channels. In this paper, we explore this phenomenon and provide its mathematical analysis. It is revealed that the variable jitter and the transmission latency difference between two successive frames are the two main sources of sequence inversion. Thus, two methods are proposed and investigated to mitigate the effects of jitter pessimism, which can eliminate the potential risk. A case study is carried out and the obtained results confirm the validity and applicability of the developed approaches.
Autors: Meng Li;Guchuan Zhu;Yvon Savaria;Michaël Lauer;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2118 - 2129
Publisher: IEEE
 
» Reliability Study of Ferroelectric Al:HfO2 Thin Films for DRAM and NAND Applications
Abstract:
Ferroelectric (FE) hafnium oxide is a promising candidate for memory applications. In this paper, endurance, imprint, and retention tests are carried out on FE aluminum-doped hafnium oxide thin films with different electrodes: 1) metal–insulator–metal (MIM) and 2) silicon–insulator–silicon(SIS). MIM devices exhibit higher endurance than SIS devices. However, SIS devices show superior imprint and retention, with an extrapolated retention time-to-failure larger than 10 years at 85 °C. These results are very promising to integrate FE-HfO2 in 3-D structures, either for dynamic random access memory or for NAND applications.
Autors: Karine Florent;Simone Lavizzari;Luca Di Piazza;Mihaela Popovici;Jingyu Duan;Guido Groeseneken;Jan Van Houdt;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4091 - 4098
Publisher: IEEE
 
» Reliable Hardware Architectures for Cryptographic Block Ciphers LED and HIGHT
Abstract:
Cryptographic architectures provide different security properties to sensitive usage models. However, unless reliability of architectures is guaranteed, such security properties can be undermined through natural or malicious faults. In this paper, two underlying block ciphers which can be used in authenticated encryption algorithms are considered, i.e., light encryption device and high security and lightweight block ciphers. The former is of the Advanced Encryption Standard type and has been considered area-efficient, while the latter constitutes a Feistel network structure and is suitable for low-complexity and low-power embedded security applications. In this paper, we propose efficient error detection architectures including variants of recomputing with encoded operands and signature-based schemes to detect both transient and permanent faults. Authenticated encryption is applied in cryptography to provide confidentiality, integrity, and authenticity simultaneously to the message sent in a communication channel. In this paper, we show that the proposed schemes are applicable to the case study of simple lightweight CFB for providing authenticated encryption with associated data. The error simulations are performed using Xilinx Integrated Synthesis Environment tool and the results are benchmarked for the Xilinx FPGA family Virtex-7 to assess the reliability capability and efficiency of the proposed architectures.
Autors: Srivatsan Subramanian;Mehran Mozaffari-Kermani;Reza Azarderakhsh;Mehrdad Nojoumian;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Oct 2017, volume: 36, issue:10, pages: 1750 - 1758
Publisher: IEEE
 

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