Electrical and Electronics Engineering publications abstract of: 11-2017 sorted by title, page: 14

» Patient-Specific Left Ventricular Flow Simulations From Transthoracic Echocardiography: Robustness Evaluation and Validation Against Ultrasound Doppler and Magnetic Resonance Imaging
Abstract:
The combination of medical imaging with computational fluid dynamics (CFD) has enabled the study of 3-D blood flow on a patient-specific level. However, with models based on gated high-resolution data, the study of transient flows, and any model implementation into routine cardiac care, is challenging. This paper presents a novel pathway for patient-specific CFD modelling of the left ventricle (LV), using 4-D transthoracic echocardiography (TTE) as input modality. To evaluate the clinical usability, two sub-studies were performed. First, a robustness evaluation was performed, where repeated models with alternating input variables were generated for six subjects and changes in simulated output quantified. Second, a validation study was carried out, where the pathway accuracy was evaluated against pulsed-wave Doppler (100 subjects), and 2-D through-plane phase-contrast magnetic resonance imaging measurements over seven intraventricular planes (6 subjects). The robustness evaluation indicated a model deviation of <12%, with highest regional and temporal deviations at apical segments and at peak systole, respectively. The validation study showed an error of <11% (velocities <10 cm/s) for all subjects, with no significant regional or temporal differences observed. With the patient-specific pathway shown to provide robust output with high accuracy, and with the pathway dependent only on 4-D TTE, the method has a high potential to be used within future clinical studies on 3-D intraventricular flow patterns. To this, future model developments in the form of e.g., anatomically accurate LV valves may further enhance the clinical value of the simulations.
Autors: David Larsson;Jeannette H. Spühler;Sven Petersson;Tim Nordenfur;Massimiliano Colarieti-Tosti;Johan Hoffman;Reidar Winter;Matilda Larsson;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Nov 2017, volume: 36, issue:11, pages: 2261 - 2275
Publisher: IEEE
 
» Patterns for Distributed Real-Time Stream Processing
Abstract:
In recent years, big data systems have become an active area of research and development. Stream processing is one of the potential application scenarios of big data systems where the goal is to process a continuous, high velocity flow of information items. High frequency trading (HFT) in stock markets or trending topic detection in Twitter are some examples of stream processing applications. In some cases (like, for instance, in HFT), these applications have end-to-end quality-of-service requirements and may benefit from the usage of real-time techniques. Taking this into account, the present article analyzes, from the point of view of real-time systems, a set of patterns that can be used when implementing a stream processing application. For each pattern, we discuss its advantages and disadvantages, as well as its impact in application performance, measured as response time, maximum input frequency and changes in utilization demands due to the pattern.
Autors: Pablo Basanta-Val;Norberto Fernández-García;Luis Sánchez-Fernández;Jesus Arias-Fisteus;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Nov 2017, volume: 28, issue:11, pages: 3243 - 3257
Publisher: IEEE
 
» Paving the Way: A Future Without Inertia Is Closer Than You Think
Abstract:
Unless you have been hibernating in a remote cave for the past decade, you will have noticed the explosion of variable renewable generation. Wind power and solar photovoltaics (PVs) have been the subject of dozens of articles, just within the pages of IEEE Power & Energy Magazine. Charts illustrating relentless growth, such as the example from the United States shown in Figure 1 with futures tending toward 100% renewable energy, are common. This figure, provided by the National Renewable Energy Laboratory (NREL), reflects a low-cost, high-renewable projection scenario.
Autors: Thomas Ackermann;Thibault Prevost;Vijay Vittal;Andrew J. Roscoe;Julia Matevosyan;Nicholas Miller;
Appeared in: IEEE Power and Energy Magazine
Publication date: Nov 2017, volume: 15, issue:6, pages: 61 - 69
Publisher: IEEE
 
» PaWaIC-PSAOFDTD: Particle-Wave Interaction Code With Pseudospectral Arbitrary-Order Accurate Temporal and Spatial Derivatives FDTD Technique for Helix TWT
Abstract:
Numerical modeling and simulations have been essential for rapid developments of vacuum electronic devices. Pseudospectral solvers have interesting capabilities to be considered, but up to now, they have not been extensively used for the modeling of vacuum tubes. In this paper, we present a novel 1-D time-domain numerical scheme which has the great aptitude of considering geometrical dispersion characteristic of helix traveling-wave tube (TWT) in time domain. This ability is interesting for one-run investigation of time-domain events such as pulse excitation of wideband tubes. The numerical model is extended to have simultaneously arbitrary order of accuracy in space and time derivations; so we achieve a code which presents a very low level of numerical dispersion error, without forcing a notable numerical calculation burden. To validate our new simulation tool, we have studied the experimental results of a TWT product, and successfully compared the results to the impulse response of the new 1-D code.
Autors: Amir Setayesh;Mohammad Sadegh Abrishamian;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4706 - 4714
Publisher: IEEE
 
» People, Technologies, and Organizations Interactions in a Social Commerce Era
Abstract:
Social commerce, a powerful combination of customer-oriented social computing technologies and new commercial features, is having an increasing impact on e-commerce, potentially generating substantial economic benefits. Drawing on socio-technical theory, this study establishes a research framework to help understand the social and technical factors affecting consumers’ intention to purchase on social commerce sites. Our results demonstrate that familiarity, user experience, learning and training, and social commerce constructs all have a positive effect on consumers’ perceptions of ease of use and usefulness, thereby enhancing their trust and intention to purchase. For systems designers and engineers, our results highlight the importance of social commerce features for building consumers’ trust of social commerce sites and supporting their intention to purchase.
Autors: Nick Hajli;Yichuan Wang;Mina Tajvidi;M. Sam Hajli;
Appeared in: IEEE Transactions on Engineering Management
Publication date: Nov 2017, volume: 64, issue:4, pages: 594 - 604
Publisher: IEEE
 
» Perfectly Secure Index Coding
Abstract:
In this paper, we investigate the index coding problem in the presence of an eavesdropper. Messages are to be sent from one transmitter to a number of legitimate receivers who have side information about the messages, and share a set of secret keys with the transmitter. To do this, the transmitter communicates to the legitimate receivers the public code , which is also heard by the eavesdropper. We assume perfect secrecy, meaning that the eavesdropper should not be able to retrieve any information about the message set from the public communication. We study the minimum key lengths for zero-error and perfectly secure index coding problem. On one hand, this problem is a generalization of the index coding problem (and thus a difficult one). On the other hand, it is a generalization of the Shannon’s cipher system. We show that a generalization of Shannon’s one-time pad strategy is optimal up to a multiplicative constant, meaning that it obtains the entire boundary of the cone formed by looking at the secure rate region from the origin. This shows the optimality of the generalized one-time pad for minimizing the consumption of shared secret keys per message bits, when public communication is free (the transmitter is not charged for the rate of the public communication). Finally, we consider relaxation of the perfect secrecy and zero-error constraints to weak secrecy and asymptotically vanishing probability of error, and provide a secure version of the result, obtained by Langberg and Effros, on the equivalence of zero-error and -error regions in the conventional index coding problem.
Autors: Mohammad Mahdi Mojahedian;Mohammad Reza Aref;Amin Gohari;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7382 - 7395
Publisher: IEEE
 
» Performance Analysis for Lossy-Forward Relaying Over Nakagami- $m$ Fading Channels
Abstract:
We investigate the performance of three-node lossy-forward (LF) relaying over independent block Nakagami- fading channels. Based on the theorem of source coding with side information, the exact outage probability expression for arbitrary values of the shape factor is derived under the assumptions of both the Gaussian codebook capacity and the constellation constrained capacity. The difference in outage probability between the two codebook models of capacity is found to be very minor. Furthermore, an accurate high signal-to-noise ratio approximation for the outage probability is obtained. It clearly identifies the equivalent diversity order and coding gain of the LF relaying. It is shown that the LF relaying is superior to conventional decode-and-forward relaying in terms of the outage probability and the -outage achievable rate. Moreover, with the LF relaying, the optimal location for the relay (R), which minimizes the outage probability, is found to be the point having same distance to the source (S) and the destination (D) when the S-R and R-D links experience the same level of fading. The accuracy of the analytical results is verified by a series of Monte Carlo simulations.
Autors: Shen Qian;Xiaobo Zhou;Xin He;Jiguang He;Markku Juntti;Tad Matsumoto;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10035 - 10043
Publisher: IEEE
 
» Performance Analysis of Nonorthogonal Multiple Access for Downlink Networks With Antenna Selection Over Nakagami-m Fading Channels
Abstract:
We investigate the system performance of a nonorthogonal multiple access (NOMA) based downlink amplify-and-forward relay network over Nakagami- fading channels with imperfect channel state information, where the base station and all users are provided with multiple antennas, while the relay is equipped with a single antenna. Two special conditions of interest (e.g., Nakagami-1, i.e., Rayleigh and Nakagami-2) are analyzed, and closed-form expression for the system outage probability is derived. Moreover, tight lower and upper bounds of the outage probability, and the outage probability in the high signal-to-interference-and-noise ratio regime, i.e., in the presence of error floor, which exists due to the channel estimation errors, are obtained. Finally, computer simulations are conducted to verify the accuracy of the numerical analysis and to confirm the superiority of the antenna selection and NOMA scheme.
Autors: Yangyang Zhang;Jianhua Ge;Erchin Serpedin;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10590 - 10594
Publisher: IEEE
 
» Performance Analysis of Reconfigurable Bandpass Filters With Continuously Tunable Center Frequency and Bandwidth
Abstract:
This paper presents a comparison and performance evaluation of three different technologies for the implementation of tunable filters utilizing semiconductor varactors, commercially available barium strontium titanate (BST) thin film and screen-printed BST thick-film varactors. To identify the most suitable technology for applications in low power receiving up to high-power transmitting stages, the performance evaluation is carried out with the same tunable hairpin filter design. While the center frequency of the proposed tunable filter structure is tuned by varactors loading the filter resonators, the bandwidth is controlled by coupling varactors between adjacent resonators. The filters are designed for a center frequency range from 700 MHz to 1 GHz and for bandwidth tuning from 60 to 150 MHz. The tunable filters are evaluated and compared with regard to their tunability, quality factor, linearity (intermodulation products of third order), and power handling capability. In conclusion, the tunable hairpin filter based on semiconductor varactor diodes offers the largest center frequency tuning range of 390 MHz with a transmission between −1.5 and −7 dB, whereas the BST thin- and thick-film-varactors-based filters exhibit high linearity with an IIP3 between 39 and 60 dBm. Moreover, large signal characterization reveals that the BST thick-film-varactors-based filter structure has the best power handling capability of up to 41dBm.
Autors: Christian Schuster;Alex Wiens;Florian Schmidt;Matthias Nickel;Martin Schüßler;Rolf Jakoby;Holger Maune;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Nov 2017, volume: 65, issue:11, pages: 4572 - 4583
Publisher: IEEE
 
» Performance Analysis of Two-Tier HetNets With Massive MIMO and Nonuniformly Small Cell Deployment
Abstract:
The performance of a coordinated multipoint transmission for massive multiple-input multiple-output (MIMO) heterogeneous networks with practical deployment is investigated. The active small cell base stations outside the inner region of macrocell base stations are used to improve the performance of macrocell edge users. Based on the stochastic geometry approach, the spectral efficiency (SE) and energy efficiency (EE) of the proposed scheme are analyzed. An alternating optimal algorithm is employed to solve the EE maximization problem effectively. The impacts of the small cell density, inner region size, and massive MIMO on the network performance are explicitly examined. Moreover, by approximating the interference distribution by moment matching with the Gamma distribution, the coverage probability of the two-tier HetNet is also studied. Numerical results show that the proposed HetNet generally outperforms the conventional maximum receive power association scheme and it provides a potential solution to achieve high SE and EE performance.
Autors: Tuong Xuan Tran;Kah Chan Teh;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10044 - 10054
Publisher: IEEE
 
» Performance and Optimization Study of a Novel Compact Permanent-Magnet-Biased Fault Current Limiter
Abstract:
The permanent-magnet-biasing saturated core fault current limiter (PMFCL) is one of the most promising devices to limit the fault current. To improve the biasing ability of permanent-magnets (PMs) and reduce the cost of PMFCL, this paper proposes a novel compact permanent-magnet-biased fault current limiter (CPMFCL). The three-limb structure can reduce the size and cost; the optimal small-section structure can improve the biasing ability of PMs and reduce the usage amount of PMs. First, the principle, equivalent magnetic circuit, and small-section optimized structure are introduced. To validate the principle and performance of CPMFCL, various finite element analysis simulation and optimization study are performed in Maxwell-3D. A 220 V/10 A CPMFCL prototype is designed and tested. The simulation and experimental results demonstrate that, compared with traditional PMFCLs, the CPMFCL has the advantages of smaller size, better biasing capacity of PMs, lower possibility of demagnetization, and excellent fault clipping performance.
Autors: Liangliang Wei;Baichao Chen;Jiaxin Yuan;Cuihua Tian;Yongheng Zhong;Xiang Li;Yanhui Gao;Kazuhiro Muramatsu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Performance and Variability Analysis of SiNW 6T-SRAM Cell Using Compact Model With Parasitics
Abstract:
In this paper, we analyze stability metrics [e.g., read, write noise margins (WNM), and access time], geometrical variability, and layout area optimization of silicon nanowire field effect transistor (SiNW FET) based 6T SRAM with multiwire sizing technique. The SRAM cell analyzed in this paper is based on the TCAD and experimentally verified SiNW FET Verilog-A compact model with parasitics. The different NW SRAM design configurations (e.g., , , etc., denotes the number of wires in pull-up, access, and pull-down transistors, respectively) are investigated. The read static noise margin and read access time (RAT) are improved up to ∼38% and ∼18% with little pay of WNM by ∼9% (↓), write access time (WAT) ∼33% (↑) in configuration compared to . Other configuration such as possess more improvements upto ∼55%, ∼20% in RNM, RAT with WNM (↓∼21%), and WAT (∼44%↑) compare to at the expense of more layout area. Finally, the impact of geometrica- variability including length, radius, and oxide thickness on the read and write stability using N-curve is examined. It is found that the static read and write stability is less susceptible to variability at nominal supply voltage. However, it is very sensitive to the voltage scaling in which read (write) voltage margin varies upto ∼2–3% (∼2.5–4.5%) and read (write) current margin varies upto ∼18% (∼35%) depending upon the design configurations. Among all design configurations, is the better configuration for considering overall performances such as write stability, speed, layout area, and variability tolerance.
Autors: Om Prakash;Satish Maheshwaram;Mohit Sharma;Anand Bulusu;Sanjeev K. Manhas;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Nov 2017, volume: 16, issue:6, pages: 965 - 973
Publisher: IEEE
 
» Performance Assessment of Vessel Dynamic Models for Long-Term Prediction Using Heterogeneous Data
Abstract:
Ship traffic monitoring is a foundation for many maritime security domains, and monitoring system specifications underscore the necessity to track vessels beyond territorial waters. However, vessels in open seas are seldom continuously observed. Thus, the problem of long-term vessel prediction becomes crucial. This paper focuses attention on the performance assessment of the Ornstein-Uhlenbeck (OU) model for long-term vessel prediction, compared with usual and well-established nearly constant velocity (NCV) model. Heterogeneous data, such as automatic identification system (AIS) data, high-frequency surface wave radar data, and synthetic aperture radar data, are exploited to this aim. Two different association procedures are also presented to cue dwells in case of gaps in the transmission of AIS messages. Suitable metrics have been introduced for the assessment. Considerable advantages of the OU model are pointed out with respect to the NCV model.
Autors: Gemine Vivone;Leonardo M. Millefiori;Paolo Braca;Peter Willett;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6533 - 6546
Publisher: IEEE
 
» Performance Bounds for Parameter Estimation under Misspecified Models: Fundamental Findings and Applications
Abstract:
Inferring information from a set of acquired data is the main objective of any signal processing (SP) method. The common problem of estimating the value of a vector of parameters from a set of noisy measurements is at the core of a plethora of scientific and technological advances in recent decades, including wireless communications, radar and sonar, biomedicine, image processing, and seismology.
Autors: Stefano Fortunati;Fulvio Gini;Maria S. Greco;Christ D. Richmond;
Appeared in: IEEE Signal Processing Magazine
Publication date: Nov 2017, volume: 34, issue:6, pages: 142 - 157
Publisher: IEEE
 
» Performance Comparison Between Reflection Symmetry Metric and Product of Multilook Amplitudes for Ship Detection in Dual-Polarization SAR Images
Abstract:
The reflection symmetry metric (RSM) and product of multilook amplitudes (PMA) detectors, which were proposed recently, have been demonstrated to be promising methods for processing dual-polarimetric synthetic aperture radar (SAR) data for ship detection. The improvements in ship detection performance by using the RSM, compared to that using the PMA, are investigated in this paper. As the ship-sea contrast (or the signal-clutter-ratio, SCR) is a central index to assess the performance of a detection method, the SCRs in the RSM and PMA are first defined and compared. Next, a theoretical explanation for why the RSM outperforms the PMA in detection performance is provided. The detection performance is then characterized by calculating the receiver operating characteristic (ROC) curves. The preliminary experimental results performed on measured RADARSAT-2, ALOS-PALSAR, and NASA/JPL AIRSAR images verify the accuracy of the theoretical analysis.
Autors: Gui Gao;Gongtao Shi;Gaosheng Li;Jianghua Cheng;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Nov 2017, volume: 10, issue:11, pages: 5026 - 5038
Publisher: IEEE
 
» Performance Comparison Between the Normal-Conducting Magnet and the Superconducting Magnet in LSM for High-Speed Propulsion
Abstract:
On the wheel-rail supported hybrid railway system, the linear synchronous motor (LSM) for very high-speed transit must be a system that can maintain a large air gap, and the maximum vertical displacement must be taken into consideration in designing the LSM. As such, this paper designs two small-scale LSM models that produce equal output power—one with the normal-conducting magnet and the other with the superconducting magnet. In addition, this paper conducts a comparative analysis of the various characteristics by applying the electromagnetic numerical analysis method. Furthermore, this paper manufactures two small-scale LSM prototypes which have the normal-conducting magnet and the superconducting magnet, while also conducting a no-load and load test. Through such comparisons, this paper attempts to verify the characteristic values of the two models.
Autors: Chan-Bae Park;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Performance Comparison of ETT- and LTT-Based Pulse Power Crowbar Switch
Abstract:
High-voltage high-power pulse switches are built with semiconductor devices, preferably thyristor, due to the superior performance that they offer. Triggering methods classify the thyristor as electrically triggered thyristor (ETT) and light triggered thyristor (LTT). Due to the specialized gate constructions and many build-in protections, the cost of LTT is much higher than ETT. The operating modes in applications, such as crowbar, do not require all these build-in protections. In this paper, the operation of a crowbar is analyzed, and the build-in protections of LTT are reviewed. This paper proposes three experiments for the design selection of thyristor, between ETT and LTT, for crowbar applications. The experiments cover the electrical performance as well as electromagnetic emissions in a 10-kV, 1-kA crowbar built with both ETT as well as LTT, which can be used to benchmark the performance of the crowbar circuit. From the three experiments, the performance of ETT-based crowbar is found to be comparable with LTT-based crowbar. Based on the experiments carried out with the proposed benchmarking approaches, this paper shows that ETT-based crowbar is a cost-effective solution for crowbar applications.
Autors: T. G. Subhash Joshi;Vinod John;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Nov 2017, volume: 45, issue:11, pages: 2994 - 3000
Publisher: IEEE
 
» Performance Factor Comparison of Nanocrystalline, Amorphous, and Crystalline Soft Magnetic Materials for Medium-Frequency Applications
Abstract:
The efficiency of electromagnetic devices is influenced by the losses of the applied soft magnetic material. Different structured materials are available. Choosing the most appropriate material for a medium-frequency application is not intuitive. Electromagnetic circuits of power transformers or electric motors are usually made of conventional silicon–iron sheets. Higher power densities can be achieved by an increased operational frequency, but the loss density increases with higher frequencies as well. Amorphous and nanocrystalline materials benefit from reduced eddy current losses at higher frequencies. In this paper, a performance factor is evaluated to determine the suitability of each material in a frequency range up to 10 kHz. The geometric parameters of electromagnetic designs depend on the applied material. A performance factor may help to identify the most appropriate material at a specific frequency. The final application is a medium-frequency transformer. The losses of the magnetic materials are measured by using standardized measurement equipment such as single sheet tester or Epstein frame. A semi-physical iron-loss model is used to describe the measured losses. These results are used to determine the performance factor.
Autors: Tobias Kauder;Kay Hameyer;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Performance Impact of Idle Mode Capability on Dense Small Cell Networks
Abstract:
Very recent studies showed that in a fully loaded dense small cell network (SCN), the coverage probability performance will continuously decrease with the network densification. Such new results were captured in IEEE ComSoc Technology News with an alarming title of “Will Densification Be the Death of 5G?” In this paper, we revisit this issue from more practical views of realistic network deployment, such as a finite number of active base stations (BSs) and user equipments (UEs), a decreasing BS transmission power with the network densification, etc. Particularly, in dense SCNs, due to an oversupply of BSs with respect to UEs, a large number of BSs can be put into idle modes without signal transmission, if there is no active UE within their coverage areas. Setting those BSs into idle modes mitigates unnecessary intercell interference and reduces energy consumption. In this paper, we investigate the performance impact of such BS idle mode capability (IMC) on dense SCNs. Different from existing work, we consider a realistic path loss model incorporating both line-of-sight (LoS) and non-LoS transmissions. Moreover, we obtain analytical results for the coverage probability, the area spectral efficiency and the energy efficiency (EE) performance for SCNs with the BS IMC and show that the performance impact of the IMC on dense SCNs is significant. As the BS density surpasses the UE density in dense SCNs, the coverage probability will continuously increase toward one, addressing previous concerns on “the death of 5G”. Finally, the performance improvement in terms of the EE performance is also investigated for dense SCNs using practical energy models developed in the Green-Touch project.
Autors: Ming Ding;David López-Pérez;Guoqiang Mao;Zihuai Lin;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10446 - 10460
Publisher: IEEE
 
» Performance Improvement of p-Channel Tin Monoxide Transistors With a Solution-Processed Zirconium Oxide Gate Dielectric
Abstract:
This letter reports the fabrication of p-channel tin monoxide (SnO) thin-film transistors (TFTs) with a high-permittivity zirconium oxide (ZrO2) gate insulator film, which were prepared by a low-cost spin-cast method. The spin-cast ZrO2 dielectrics exhibit a low leakage current density of A/cm2 at 1 MV/cm. Introducing the ZrO2 dielectric in top-type SnO TFTs allows for a reduction in the driving gate voltage range from 80 to 10 V, as compared with devices with a thermal SiO2 gate insulator. Additionally, a high field-effect mobility of 2.5 cm2/Vs and an of were preserved.
Autors: Azida Azmi;Jiwon Lee;Tae Jung Gim;Rino Choi;Jae Kyeong Jeong;
Appeared in: IEEE Electron Device Letters
Publication date: Nov 2017, volume: 38, issue:11, pages: 1543 - 1546
Publisher: IEEE
 
» Performance of Energy-Harvesting Receivers With Time-Switching Architecture
Abstract:
The analysis and optimization of energy-harvesting transmitters and receivers are different. This paper considers an end-to-end communication with an energy-harvesting receiver. The receiver has a time-switching architecture and can harvest energy from both a dedicated transmitter and other ambient radio-frequency (RF) sources. We first argue that the energy consumed for decoding (per channel use) can be expressed in terms of the gap to channel capacity and utilize this model to optimize two schemes for receiver operation. The two schemes are harvest-then-receive and harvest-when-receive, and they differ primarily in how and when they use the harvested energy for decoding. For transmission over a single block, we compare their performance from various aspects. Then we consider transmission over multiple blocks. When the energy harvested is all from the transmitter, we provide the solution for choosing the optimal code rate and fraction of channels used for energy harvesting for each block. When the energy harvested can also be from other RF sources, we provide a table-search algorithm to find a solution. Finally, we present some numerical examples to validate the accuracy of our analysis.
Autors: Zhengwei Ni;Mehul Motani;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7252 - 7263
Publisher: IEEE
 
» Performance of Generalized Frequency Division Multiplexing Based Physical Layer in Vehicular Communications
Abstract:
Vehicular communications enable information exchange among vehicles including the roadside infrastructure. This has led to applications to primarily increase road safety and traffic efficiency. Standardization efforts on vehicular communications are underway. The physical layer (PHY) is defined based on the IEEE 802.11 family of WiFi standards operating at the 5.9 GHz frequency band and on extensions of long-term evolution (LTE); in both cases orthogonal frequency division multiplexing (OFDM) is the waveform of choice. Since the typical environment of WiFi deployment is very different to the vehicular communication environment, it is a challenging task to adapt the WiFi-based PHY for providing reliable and real-time communications under highly time- and frequency-selective fading channels. In this paper, the employment of an alternative waveform termed generalized frequency division multiplexing (GFDM) for vehicular communication is investigated. Specifically, a GFDM-based packet design is proposed on the basis of the standard-compliant OFDM-based PHY configuration. On the receiver side, this paper focuses on developing synchronization, channel estimation, and equalization algorithms. The performance of the resulting GFDM-based PHY is verified and compared with the OFDM-based one by means of simulation. The obtained results demonstrate that the proposed GFDM-based PHY can utilize the time and frequency resources more efficiently, and outperform particularly under challenging channel conditions. Additionally, the low out-of-band emission of GFDM is a desirable feature for future multichannel operation (MCO) in vehicular communications.
Autors: Dan Zhang;Andreas Festag;Gerhard P. Fettweis;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 9809 - 9824
Publisher: IEEE
 
» Performance Scaling Law for Multicell Multiuser Massive MIMO
Abstract:
This paper provides a comprehensive scaling law-based performance analysis for multicell multiuser massive multiple-input-multiple-output (MIMO) downlink systems. Imperfect channel state information (CSI), pilot contamination, and channel spatial correlation are all considered. First, a sum-rate lower bound is derived by exploiting the asymptotically deterministic property of the received signal power, while keeping the random nature of other components in the signal-to-interference-plus-noise-ratio (SINR) intact. Via a general scaling model on important network parameters, including the number of users, the channel training energy and the data transmission power, with respect to the number of base station antennas, the asymptotic scaling law of the effective SINR is obtained, which reveals quantitatively the tradeoff of the network parameters. More importantly, pilot contamination and pilot contamination elimination (PCE) are considered in the analytical framework. In addition, the applicability of the derived asymptotic scaling law in practical systems with large but finite antenna numbers are discussed. Finally, sufficient conditions on the parameter scalings for the SINR to be asymptotically deterministic in the sense of mean square convergence are provided, which covers existing results on such analysis as special cases and shows the effect of PCE explicitly.
Autors: Cheng Zhang;Yindi Jing;Yongming Huang;Luxi Yang;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 9890 - 9903
Publisher: IEEE
 
» Performance-Based Linearization Approach for Modeling Induction Motor Drive Loads in Dynamic Simulation
Abstract:
This paper describes a technique to model a vector-controlled induction motor drive in large-scale phasor-level dynamic simulation programs. The performance-based load model is implemented by obtaining the linearized power-voltage and power-frequency transfer functions from test data or from detailed electro-magnetic transient simulation used as a surrogate for test data. Voltage and frequency modulations are performed to obtain the amplitude and phase responses of the detailed vector-controlled drive model for a range of discrete frequencies. The prediction error minimization technique is utilized to generate best-fit analytical transfer function expressions. The electrical interface of the performance-based drive load model is developed to interact with the external system in positive-sequence dynamic simulation programs. The drive model is used to investigate the relative damping effects of drive-connected and direct-connected motors on system voltage and frequency oscillations.
Autors: Yuan Liu;Vijay Vittal;John Undrill;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4636 - 4643
Publisher: IEEE
 
» Performances Analysis of Coherently Integrated CPF for LFM Signal Under Low SNR and Its Application to Ground Moving Target Imaging
Abstract:
The detection and parameters estimation of linear frequency-modulated (LFM) signal are important for modern radar applications, but they are also challenged by the fact that echo signal is often of low signal-to-noise ratio (SNR) due to reasons of long imaging distance and/or limited transmitted power, and the target of small size and/or hidden characteristics. To enhance the SNR, in our previous work, a novel coherently integrated cubic phase function (CICPF) was recently developed for the parameters estimation of the multicomponent LFM signal. In the CICPF, the auto-terms are coherently integrated to enhance the performance in the case of low SNR and also to suppress the cross-terms and spurious peaks. In this paper, as an extension of our previous work, the theoretical performance analyses including several important properties and the fast implementation are provided. Furthermore, the asymptotic mean squared error of a CICPF-based estimator as well as the output SNR of a CICPF-based detector are theoretically derived in closed-forms. From the performance point of view, the proposed CICPF attains the Cramer-Rao bound at low input SNR. The complexity analysis also indicates that the CICPF with the nonuniform fast Fourier transform is computationally efficient without needing the interpolation operation and parameter search. Numerical studies of the CICPF confirm the theoretical analysis and demonstrate superior performance of the proposed approach compared with other state-of-the-art approaches, especially under the low-SNR condition. Finally, the proposed CICPF is applied for the ground moving target imaging in synthetic aperture radar. Results using simulated and experimental data demonstrate that it provides an effective means to obtain well-focused image for ground moving targets.
Autors: Dong Li;Muyang Zhan;Jia Su;Hongqing Liu;Xuepan Zhang;Guisheng Liao;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6402 - 6419
Publisher: IEEE
 
» Perpendicular Grating Coupler Based on a Blazed Antiback-Reflection Structure
Abstract:
Silicon photonic grating couplers are demonstrated featuring a perfect vertical coupling and predicted coupling efficiencies of 87% and 78% with an apodized and a standard periodic structure, respectively. Vertical coupling is usually difficult to be achieved with standard diffraction gratings, since both the forward and backward scattered light meet the Bragg condition alike. In this work a vertical grating coupler which satisfies both high directionality (> 97%) and low back-reflection (<; 1%) simultaneously is realized using a blazed sub-wavelength structure. The measured maximum coupling efficiencies with a standard single-mfiber are -1.5 dB and -2.2 dB for apodized and periodic structures, respectively. The suggested structure offers an ultimate solution for compact coupling schemes in Si photonics, since it meets the most important needs of grating couplers, which are directionality, ease of fabrication, and a possibility to vertically couple. The vertical grating coupler are fabricated on a silicon-on-insulator wafer with a 220 nm-thick silicon layer, relying only on a 2-step etching technology.
Autors: Tatsuhiko Watanabe;Masafumi Ayata;Ueli Koch;Yuriy Fedoryshyn;Juerg Leuthold;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4663 - 4669
Publisher: IEEE
 
» Perpendicular-Corporate Feed in Three-Layered Parallel-Plate Radiating-Slot Array
Abstract:
We propose a perpendicular-corporate feed in a three-layered parallel-plate radiating-slot array to remove the x-shaped cavity walls completely in the radiating part of the conventional planar corporate-feed waveguide slot array antenna. Coupling apertures on the bottom excite radiating slots spaced with the half of their spacing on the middle in the parallel plates. We place dielectric with proper permittivity in the region between the coupling aperture and the radiating-slot layer to excite a standing wave strongly there for a large number of slots. A parasitic-slot layer is added on the top to improve the bandwidth. A slot array antenna is designed for uniform excitation with the perpendicular and the planar corporate feeds, and fabricated in the 60 GHz band. At the design frequency of 61.5 GHz, the measured directivity is 33.5 dBi with the aperture efficiency of 90.6%.
Autors: Hisanori Irie;Jiro Hirokawa;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 5829 - 5836
Publisher: IEEE
 
» Personalized Prediction of Vehicle Energy Consumption Based on Participatory Sensing
Abstract:
The advent of abundant on-board sensors and electronic devices in vehicles populates the paradigm of participatory sensing to harness crowd-sourced data gathering for intelligent transportation applications, such as distance-to-empty prediction and eco-routing. While participatory sensing can provide diverse driving data, there lacks a systematic study of effective utilization of the data for personalized prediction. There are considerable challenges on how to interpolate the missing data from a sparse data set, which often arises from participatory sensing. This paper presents and compares various approaches for personalized vehicle energy consumption prediction, including a blackbox framework that identifies driver/vehicle/environment-dependent factors and a collaborative filtering approach based on matrix factorization. Furthermore, a case study of distance-to-empty prediction for electric vehicles by participatory sensing data is conducted and evaluated empirically, which shows that our approaches can significantly improve the prediction accuracy.
Autors: Chien-Ming Tseng;Chi-Kin Chau;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Nov 2017, volume: 18, issue:11, pages: 3103 - 3113
Publisher: IEEE
 
» Personalized Social Image Recommendation Method Based on User-Image-Tag Model
Abstract:
In the social image sharing websites (such as Flickr), users are allowed to upload images and tag them with tags. Due to the diversities of users' interests, different users may tag the same image with different tags. Therefore, tags not only reveal some important image semantic clues, but also show user's preference, which can provide a new effective solution for overcoming the semantic gap as well as realizing a personalized recommendation. In this paper, a personalized social image recommendation method based on user-image-tag model is proposed. The main contributions of our work are 1) to efficiently make use of tags, social image tags are re-ranked according to the image content; 2) to obtain user preference, a user-image-tag model is constructed with tripartite graph according to the correlation among users, images and top-ranking tags; and 3) a personalized social recommendation system is implemented based on user-image-tag model. Experimental results proved that our method can significantly improve the accuracy of personalized image recommendation.
Autors: Jing Zhang;Ying Yang;Qi Tian;Li Zhuo;Xin Liu;
Appeared in: IEEE Transactions on Multimedia
Publication date: Nov 2017, volume: 19, issue:11, pages: 2439 - 2449
Publisher: IEEE
 
» PF1000 High-Energy Plasma Focus Device Operated With Neon as a Copious Soft X-Ray Source
Abstract:
The measured current waveforms of PF1000 plasma focus operating in neon are first fitted to the computed currents using the Lee model for the pressures of 0.5 and 0.8 torr. The fitting fixes the model parameters. The code is then run to study and to optimize the soft X-ray yield from (~352 kJ) PF1000 device. The maximum characteristic soft X-ray (H-like and He-like lines) yield of 4.2 kJ is found to occur at the pressure of 0.85 torr, with the pinch duration of 207 ns and with an all-line yield of 4.8 kJ. Maximum compression (corresponding to smallest pinch radius) of 0.585 cm with the duration of 224 ns is obtained at 1 torr with the greatest all-line yield of 7.1 kJ but a lower characteristic soft X-ray yield of 3.2 kJ. Detailed computation results indicate that the maximum compression (minimum pinch radius) at 1 torr is attributed to two mechanisms: thermodynamics specific heat ratio effects and radiative losses.
Autors: Mohamad Akel;S. Ismael;S. Lee;S. H. Saw;H. J. Kunze;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Nov 2017, volume: 45, issue:11, pages: 2979 - 2983
Publisher: IEEE
 
» Phase and Hyperfine Structures of Melt-spun Nanocrystalline (Ce1–xNdx)16Fe78B6 Alloys
Abstract:
To reduce the cost of the Nd–Fe–B magnets, the Ce element was suggested to be used as a replacement of Nd element. In this paper, nanocrystalline (Ce1–xNdx)16Fe78B6 (–0.7) alloys were prepared by melt spinning. The X-ray diffraction (XRD) results indicate that the alloys are composed of (NdCe)2Fe14B (2:14:1) phase and (CeNd)Fe2 (1:2) phase for 0 < 0.6, and the 1:2 phase was replaced by (NdCe)Fe4B4 (1:4:4) phase when and 0.7. The hyperfine parameters characteristics of the 2:14:1 phases were estimated from 300 K 57Fe Mössbauer spectra, as well as their contents and those of other intergranular phases. In addition to the 2:14:1, 1:2, and 1:4:4 phases, a small content of the rare earth-rich phase was also detected in all the alloys, which was not able to be observed by the XRD characterization. Based upon the hyperfine field, the average magnetic moment of Fe in 2:14:1 phase could be determined as 1.56, 1.62, 1.67, 1.73, 1.78, 1.83, 1.85, and for , 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7, respectively. The minor change between the ( and is discussed. Both the present local and macroscopic magnetic parameters significantly contribute to understand the fundamental role of Ce in those nanocrystalline Nd–Ce–Fe–B permanent magnets.
Autors: L. Z. Zhao;H. Y. Yu;W. T. Guo;J. S. Zhang;Z. Y. Zhang;M. Hussain;Z. W. Liu;J. M. Greneche;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Phase Compensation Scheme for Fiber-Optic Interferometric Vibration Demodulation
Abstract:
In order to expand the dynamic range of fiber-optic interferometric demodulation, a novel phase compensation scheme based on the phase generated carrier arctangent algorithm (PGC-arctan) is proposed, which overcomes the limitation of the amplitude range from to for arbitrary signals; and a Michelson interferometer measurement system is established to verify the rationality of the compensation algorithm. The phase compensation algorithm is based on analysis of the instantaneous function of the arctangent signal during the phase hopping process, while overcoming the problem of phase winding. Experimental results confirmed the feasibility of the phase compensation scheme as predicted by theoretical and simulation analysis. In particular, the new scheme was shown to be effective in responding to arbitrary large-amplitude and time-dependent vibrational input, with the additional benefit of a strong ability to suppress system and ambient noise.
Autors: Tianying Chang;Jinpeng Lang;Wei Sun;Jiandong Chen;Miao Yu;Wenzhi Gao;Hong-Liang Cui;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7448 - 7454
Publisher: IEEE
 
» Phase Stabilities and Magnetic Properties of Mn-Deficient and Ge-Substituted Mn3Ga With D022 Structure
Abstract:
We have investigated phase stabilities and magnetic properties of the tetragonal D022 phase in Mn-deficient Mn3–xGa and Ge-substituted Mn3Ga1–yGey. A transition from the D022 to L10 phase is observed in the composition range of –0.8 in Mn3–xGa. On the other hand, the D022 phase is confirmed in the overall composition of Mn3Ga1–yGey. The thermal stability of the D022 phase strongly depends on the Ge content compared with the Mn deficiency. Magnetization of Mn3–xGa is increased by introducing the Mn deficiency, whereas that of Mn3Ga1–yGey decreases with increasing Ge content despite a constant number of Mn atoms. This result suggests that the magnitude of magnetic moment of Mn atom in Mn3Ga1–yGey is influenced by variations of valence electron and structural properties caused by the Ge substitution.
Autors: Hironari Okada;Toru Sasaki;Yudai Syoji;Rie Y. Umetsu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Phase-Change Memory—Towards a Storage-Class Memory
Abstract:
Phase-change memory (PCM) has undergone significant academic and industrial research in the last 15 years. After much development, it is now poised to enter the market as a storage-class memory (SCM), with performance and cost between that of NAND flash and DRAM. In this paper, we review the history of phase-transforming chalcogenides leading up to our current understanding of PCM as either a storage-type SCM, with high-density and better than NAND flash endurance, write speeds, and retention, or a memory-type SCM, with fast read/write times to function as a nonvolatile DRAM. Several of the key findings from the community relating to device dimensional scaling, cell design, thermal engineering, material exploration, and storing multiple levels per cell will be discussed. These areas have dramatically impacted the course of development and understanding of PCM. We will highlight the performance gains attained and the future prospects, which will help drive PCM to be as ubiquitous as NAND flash in the upcoming decade.
Autors: Scott W. Fong;Christopher M. Neumann;H.-S. Philip Wong;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4374 - 4385
Publisher: IEEE
 
» Photoconductance Decay Characterization of 3D Multi-Fin Silicon on SOI Substrates
Abstract:
This letter is concerned with the electrical characterization of 3D fin-shaped silicon used as a channel in novel transistor architectures. This approach adapts photoconductance decay minority carrier measurement methodology to the needs of electrical characterization of fin-shaped semiconductor materials systems. The results obtained indicate as high as threefold decrease in the minority carrier lifetime in the fin-shaped Si as compared with the same active planar Si prior to fins definition (from to ). A cause of this decrease is significant expansion of the effective surface area of the finned samples and the resulting increase in recombination sites related to the structurally disordered sidewalls of the fins formed via etching. Hydrogen termination of the finned surfaces did not provide long-term passivation of the surfaces, which was accomplished only by atomic layer deposition of 3-nm-thick layer of Al2O3.
Autors: P. J. Drummond;A. Wali;M. J. Barth;A. M. Diehm;S. Datta;J. Ruzyllo;
Appeared in: IEEE Electron Device Letters
Publication date: Nov 2017, volume: 38, issue:11, pages: 1513 - 1515
Publisher: IEEE
 
» Physical-Based Analytical Model of Amorphous InGaZnO TFTs Including Deep, Tail, and Free States
Abstract:
Amorphous InGaZnO (a-IGZO) is a candidate material for thin-film transistors (TFTs) owing to its large electron mobility and good uniformity over large area. a-IGZO TFTs drain current models are essential for further pushing both a-IGZO TFTs technology and circuit design. In this paper, we propose a simple physical-based and analytical model of the drain current of a-IGZO TFTs. The model is valid in both non degenerate and degenerate conduction and it accounts for deep interface states, tail localized states, and free delocalized band states. The model is validated with the measurements of both coplanar and staggered a-IGZO TFTs. It provides key physical and material parameters of the transistor and, owing to its class formulation, it can be straightforwardly implemented in circuit simulators.
Autors: Matteo Ghittorelli;Zsolt Miklós Kovács-Vajna;Fabrizio Torricelli;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4510 - 4517
Publisher: IEEE
 
» Physical-Layer Security in MCF-Based SDM-EONs: Would Crosstalk-Aware Service Provisioning be Good Enough?
Abstract:
In this paper, we consider a multicore fiber (MCF)-enabled elastic optical network, in which certain nodes have a lower trust level than the others, and study how to provision lightpaths with considerations of the impairments and security vulnerabilities caused by intercore crosstalk. We propose attack-aware routing, spectrum, and core assignment algorithms that give priority to avoiding physical-layer security threats and then try to reduce the crosstalk-induced impairments. Specifically, both static network planning and dynamic network provisioning are investigated. For static planning, we first formulate an integer linear programming (ILP) model to optimize the spectrum utilization and intercore crosstalk level jointly and then propose a time-efficient heuristic. Simulation results confirm that the proposed heuristic can approximate the ILP's performance with much higher time efficiency in a small-scale network and outperform an existing benchmark in large networks. For dynamic provisioning, we design a heuristic to balance the tradeoff between blocking probability and crosstalk and conduct extensive simulations to verify its effectiveness.
Autors: Jing Zhu;Zuqing Zhu;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:22, pages: 4826 - 4837
Publisher: IEEE
 
» PIC: Enable Large-Scale Privacy Preserving Content-Based Image Search on Cloud
Abstract:
Many cloud platforms emerge to meet urgent requirements for large-volume personal image store, sharing and search. Though most would agree that images contain rich sensitive information (e.g., people, location and event) and people’s privacy concerns hinder their participation into untrusted services, today’s cloud platforms provide little support for image privacy protection. Facing large-scale images from multiple users, it is extremely challenging for the cloud to maintain the index structure and schedule parallel computation without learning anything about the image content and indices. In this work, we introduce a novel system PIC: A Privacy-preserving Image search system on Cloud, which is a step towards feasible cloud services which provide secure content-based large-scale image search with fine-grained access control. Users can search on others’ images if they are authorized by the image owners. Majority of the computationally intensive jobs are handled by the cloud, and a querier can now simply send the query and receive the result. Specially, to deal with massive images, we design our system suitable for distributed and parallel computation and introduce several optimizations to further expedite the search process. Our security analysis and prototype system evaluation results show that PIC successfully protects the image privacy at a low cost of computation and communication.
Autors: Lan Zhang;Taeho Jung;Kebin Liu;Xiang-Yang Li;Xuan Ding;Jiaxi Gu;Yunhao Liu;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Nov 2017, volume: 28, issue:11, pages: 3258 - 3271
Publisher: IEEE
 
» Pickup Coil Counter for Detecting the Presence of Trains Operated by Wireless Power Transfer
Abstract:
An axle counter is a popularly used device for detecting passing trains. They detect train wheels by the change of the magnetic field, made by the train wheels, in a receiving coil. Wireless power transfer (WPT) systems are used to deliver tractive power to electric trains by magnetic resonance. They consist of a pickup coil onboard the train, a supply coil on the track, and related trackside electronic circuits. When a WPT system is proximate to an axle counter, the magnetic field of the WPT can produce significant electromagnetic interference, significantly affecting the performance of the axle counter. Since the WPT system is an emerging power supply system for future railways, an alternative device for detecting trains is considered necessary. A novel device called the pickup coil counter (PCC) is proposed for this purpose. Unlike the axle counter, which detects the train’s wheels, the PCC detects the WPT pickup coil onboard the train using a sensor coil wound around the WPT supply coil on the track and a detection circuit in trackside equipment. The operating concept of the PCC is explained. Its detection performance was evaluated by 3-D FEM simulation and experiment, and the results are presented.
Autors: Karam Hwang;Dongwook Kim;Dongsoo Har;Seungyoung Ahn;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7526 - 7532
Publisher: IEEE
 
» Piezomagnetic Performance of Stress-Annealed FeAlB Alloys
Abstract:
Two FeAlB polycrystalline alloys were stress annealed and had the piezomagnetic behavior determined before and after the stress annealing (SA). The concentration of boron is constant, 1.6% (at%). The alloys are basically formed by the phase Fe2B dispersed in a bcc matrix. The bcc matrix can be formed of a disordered and/or ordered structure, depending on ratio of Fe:Al, that was fixed as 86Fe:14Al and 80Fe:20Al. Magnetostriction and magnetic induction were measured as a function of magnetic field and compressive stresses. The piezomagnetic coefficient improvement due to SA was achieved, in which is the magnetostriction and H the applied magnetic field. SA causes the reorientation of the magnetic moment of the material creating an artificial magnetic anisotropy. The behavior of the coefficient d33 varies due to changes in Al content, since the magnetocrystalline anisotropy of the alloy depends on the ordering of the bcc matrix. Values of d33 up to 4 nm/A were reached for the polycrystalline alloy with 14% Al (at%) in an interval of compressive stresses of MPa. This large interval of compression stress is due to the presence of the Fe2B phase.
Autors: Cristina Bormio-Nunes;Mateus Botani de Souza Dias;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Plasma Exposure Behavior of Yttrium Oxide Film Formed by Aerosol Deposition Method
Abstract:
Aerosol deposition (AD) method is technique for forming high density ceramic films on substrate material surface at room temperature. The yttrium oxide films formed by the AD method (AD-Y2O3 films) have been developed as plasma resistance coating used for the plasma etching equipment. In recent years, plasma eroded particles from chamber components of the etching devices are regarded as a serious issue that they reduce the semiconductor device yield rate. AD-Y2O3 films which have excellent plasma resistance can reduce the eroded particles in the plasma etching equipment and greatly have contributed to manufacturing high integrated semiconductor devices. In this paper, the plasma erosion behavior of AD-Y2O3 films were investigated compared with sintered Al2O3, sintered Y2O3 and thermal splayed Y2O3 in order to clarify the reason why AD Y2O3 films were superior as plasma resistance material. The plasma etching rates of AD-Y2O3 films were not significantly different from other samples. It was assumed that the etching rates were dependent on the chemical stability to fluorine plasma of material. On the other hand, the surface roughness difference before and after plasma exposure of AD-Y2O3 films were much smaller than other samples. It was assumed that the surface roughness difference is dependent on the crystalline size of material. The structure of AD-Y2O3 films, which had high density and nano-crystalline structure, were eroded homogeneously and smoothly. It suggests AD-Y2O3 films do not generate large eroded particles and are superior to reduce the eroded particles in the etching devices.
Autors: Hiroaki Ashizawa;Masakatsu Kiyohara;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 357 - 361
Publisher: IEEE
 
» Plasma Response to Resonant Magnetic Perturbations in Large Aspect Ratio Tokamaks
Abstract:
In this paper, a plasma response model is investigated for large aspect ratio tokamaks, on the presence of external nonaxisymmetric resonant magnetic perturbations. To control plasma confinement, the plasma is perturbed by external resonant helical windings, similar to those introduced by an ergodic magnetic limiter. The plasma response to the perturbation is modeled as an additional magnetic perturbation, created by a current sheet on the main perturbed resonant surface, vanishing the radial component of the total magnetic field in the considered resonant surface. In order to show the influence of the plasma response on the field line topology, the field line differential equations are integrated numerically, showing the reduction of magnetic island sizes and the regularization of chaotic regions around the resonant surface where the response was introduced, in agreement with results observed in sophisticated simulation codes. Finally, the connection lengths indicate that, regarding their distribution, the plasma response introduces a homogenization effect which may affect the deposition patterns at the tokamak wall.
Autors: André Carlos Fraile;Marisa Roberto;Iberê Luiz Caldas;Caroline Gameiro Lopes Martins;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Nov 2017, volume: 45, issue:11, pages: 2906 - 2912
Publisher: IEEE
 
» PlatEMO: A MATLAB Platform for Evolutionary Multi-Objective Optimization [Educational Forum]
Abstract:
Over the last three decades, a large number of evolutionary algorithms have been developed for solving multi-objective optimization problems. However, there lacks an upto-date and comprehensive software platform for researchers to properly benchmark existing algorithms and for practitioners to apply selected algorithms to solve their real-world problems. The demand of such a common tool becomes even more urgent, when the source code of many proposed algorithms has not been made publicly available. To address these issues, we have developed a MATLAB platform for evolutionary multi-objective optimization in this paper, called PlatEMO, which includes more than 50 multiobjective evolutionary algorithms and more than 100 multi-objective test problems, along with several widely used performance indicators. With a user-friendly graphical user interface, PlatEMO enables users to easily compare several evolutionary algorithms at one time and collect statistical results in Excel or LaTeX files. More importantly, PlatEMO is completely open source, such that users are able to develop new algorithms on the basis of it. This paper introduces the main features of PlatEMO and illustrates how to use it for performing comparative experiments, embedding new algorithms, creating new test problems, and developing performance indicators. Source code of PlatEMO is now available at: http://bimk.ahu.edu.cn/index.php?s=/Index/Software/index.html.
Autors: Ye Tian;Ran Cheng;Xingyi Zhang;Yaochu Jin;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Nov 2017, volume: 12, issue:4, pages: 73 - 87
Publisher: IEEE
 
» Polar Channel Coding Schemes for Two-Dimensional Magnetic Recording Systems
Abstract:
This paper proposes new two-dimensional magnetic recording (TDMR) systems using polar channel coding as practical error correction coding. It is known that the time and space complexities of the encoding/decoding algorithms based on polar channel coding are , where is the codeword (block) length. If we compare the error-correction performance of a polar code with that of a low-density parity-check (LDPC) code in the same rate, it is known that the polar code has a longer length and its decoder still has a lower implementation complexity than the LDPC decoder. Therefore, relatively low-complexity coding schemes are preferable for any TDMR systems under high rates and relatively long codeword lengths. In this paper, the proposed TDMR system serially concatenates a two-dimensional (2-D) modulation code with one-dimensional (1-D) polar codes in each down-track direction. These element polar codes are designed on the fundamentals of the channel polarization theory, which are applied for channels with memory. Actually, it evaluates the performance of the signal processing scheme with concatenated coding and generalized partial response equalization for the proposed TDMR system using bit-patterned media by computer simulations. As a result, it shows that the block error rate performance of the proposed TDMR system with the 2-D modulation and polar channel coding schemes is superior to that of the 1-D system with the conventional 1-D high rate modulation and LDPC coding schemes.
Autors: Hidetoshi Saito;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 7
Publisher: IEEE
 
» Polar Opinion Dynamics in Social Networks
Abstract:
For decades, scientists have studied opinion formation in social networks, where information travels via word of mouth. The particularly interesting case is when polar opinions—Democrats versus Republicans or iOS versus Android—compete in the network. The central problem is to design and analyze a model that captures how polar opinions evolve in the real world. In this paper, we propose a general nonlinear model of polar opinion dynamics, rooted in several theories of sociology and social psychology. The model's key distinguishing trait is that unlike in the existing linear models, such as DeGroot and Friedkin–Johnsen models, an individual's susceptibility to persuasion is a function of his or her current opinion. For example, a person holding a neutral opinion may be rather malleable, while “extremists” may be strongly committed to their current beliefs. We also study three specializations of our general model, whose susceptibility functions correspond to different sociopsychological theories. We provide a comprehensive theoretical analysis of our nonlinear models’ behavior using several tools from nonsmooth analysis of dynamical systems. To study convergence, we use nonsmooth max–min Lyapunov functions together with the generalized Invariance Principle. For our general model, we derive a general sufficient condition for the convergence to consensus. For the specialized models, we provide a full theoretical analysis of their convergence—whether to consensus or disagreement. Our results are rather general and easily apply to the analysis of other nonlinear models defined over directed networks, with Lyapunov functions constructed out of convex components.
Autors: Victor Amelkin;Francesco Bullo;Ambuj K. Singh;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5650 - 5665
Publisher: IEEE
 
» Polarimetric SAR Image Classification Using a Wishart Test Statistic and a Wishart Dissimilarity Measure
Abstract:
Land-cover classification in polarimetric synthetic aperture radar images is a vital technique that has been developed for years. The Wishart distribution, which the polarimetric coherence matrix obeys, has been researched to design the well-known Wishart classifier. This model is appropriate for homogeneous scenes, but it usually fails in reality when a category consists of several subcategories or clusters. Therefore, a simple but powerful sample-merging strategy is proposed to generate representative subcenters, based on a dissimilarity measure. In addition, a weighted likelihood-ratio criterion is also proposed to further improve the performance of the Wishart distribution-based classification, based on the Wishart test statistic. Two experiments on EMISAR and UAVSAR data sets confirm that combining the proposed strategies can achieve better results than can the Wishart classifier and the other existing methods.
Autors: Weidong Sun;Pingxiang Li;Jie Yang;Lingli Zhao;Minyi Li;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 2022 - 2026
Publisher: IEEE
 
» Polarity Control of GaN and Realization of GaN Schottky Barrier Diode Based on Lateral Polarity Structure
Abstract:
This paper reports investigation on a polarity control scheme of GaN thin films and realization of Schottky barrier diode (SBD) fabricated on a lateral-polarity-structure (LPS) GaN without intentionally doping. Specifically, Ga-polar and N-polar GaN were grown simultaneously side by side on sapphire substrate with patterned AlN buffer. Due to the surface energy difference between two polarities, N-polar regions are n-type conductive with rough surface morphology, while Ga-polar regions are semi-insulating with atomic flat surface morphology. Annealing conditions of both ohmic contact and Schottky contact were investigated. Current–voltage (I–V) characteristic revealed that the SBD fabricated on LPS GaN has higher forward current, barrier height closer to 0.7 eV, and ideality factor closer to unity compared to SBD fabricated on conventional undoped GaN. The specific on-state resistance ( for the SBD based on LPS GaN is 77 lower than the SBD fabricated on conventional GaN. With oxide passivation on SBD surface, forward current exceeds 0.2 A at 10 V, while reverse current is less than 10−5 A at −10 V, respectively. The utilization of LPS in SBD demonstrates a promising approach for the development of lateral n+/n SBD with a simple fabrication scheme.
Autors: Moheb Sheikhi;Junmei Li;Fanping Meng;Hongwei Li;Shiping Guo;Lingyan Liang;Hongtao Cao;Pingqi Gao;Jichun Ye;Wei Guo;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4424 - 4429
Publisher: IEEE
 
» Polarization of the Rényi Information Dimension With Applications to Compressed Sensing
Abstract:
In this paper, we show that the Hadamard matrix acts as an extractor over the reals of the Rényi Information Dimension (RID), in an analogous way to how it acts as an extractor of the discrete entropy over finite fields. More precisely, we prove that the RID of an i.i.d. sequence of mixture random variables polarizes to the extremal values of 0 and 1 (corresponding to discrete and continuous distributions) when transformed by a Hadamard matrix. Furthermore, we prove that the polarization pattern of the RID admits a closed form expression and follows exactly the Binary Erasure Channel (BEC) polarization pattern in the discrete setting. We discuss the applications of the RID polarization to Compressed Sensing of i.i.d. sources. In particular, we use the RID polarization to construct a family of deterministic ±1-valued sensing matrices for Compressed Sensing. We run numerical simulations to compare the performance of the resulting matrices with that of the random Gaussian and the random Hadamard matrices. The results indicate that the proposed matrices afford competitive performances, while being explicitly constructed.
Autors: Saeid Haghighatshoar;Emmanuel Abbe;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 6858 - 6868
Publisher: IEEE
 
» Polarization Shift Keying (PolarSK): System Scheme and Performance Analysis
Abstract:
The single-radio-frequency (RF) multiple-input-multiple-output (MIMO) system has been proposed to pursue a high spectral efficiency while keeping a low hardware cost and complexity. Recently, the available degrees of freedom (DoF) in the polarization domain has been exploited to reduce the size of the transmit antenna array and provide 1 bit per channel use (bpcu) multiplexing gain for the single-RF MIMO system. Nevertheless, the polarization domain resource still has the potential to provide a higher multiplexing gain in the polarized single-RF MIMO system. In this paper, we propose a generalized polarization shift keying (PolarSK) modulation scheme that uses polarization states in the dual-polarized transmit antenna as an information-bearing unit to increase the overall spectral efficiency. At the receiver, the optimum maximum likelihood (ML) detector is employed to investigate the ultimate performance limit of the PolarSK. A closed-form union upper bound on the average bit error probability (ABEP) of the PolarSK with the optimum ML receiver is derived. Inspired by the analytic ABEP, a constellation diagram optimization algorithm is proposed. To reduce the computational complexity of the receiver, a linear successive interference cancellation (SIC) detection algorithm and a sphere-decoding (SD) detection algorithm are introduced. Through numerical results, performances of the proposed PolarSK in terms of ABEP and computational complexity are analyzed. Furthermore, the PolarSK is analyzed over measured indoor channels. Numerical and measurement results show that the PolarSK scheme outperforms the state-of-the-art dual-polarized/unipolarized SM schemes.
Autors: Jiliang Zhang;Yang Wang;Jie Zhang;Liqin Ding;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10139 - 10155
Publisher: IEEE
 
» Polarization-Adjustable Planar Array Antenna With SIW-Fed High-Order-Mode Microstrip Patch
Abstract:
This communication presents a high-order-mode microstrip patch antenna driven by substrate integrated waveguide (SIW) for millimeter-wave polarization-adjustable applications. Different polarization status can be yielded from variable excited signals, including vertical and horizontal linear, right-handed and left-handed circular polarizations. In the patch antenna configuration, an enlarged aperture coming from high-order mode makes it easy to be fed by orthogonal SIWs for dual polarizations. Loaded slots on the patch significantly improve the radiation patterns. The impedance bandwidth with dual resonances is originated from the SIW slot and patch modes. A Ka-band antenna array integrated with single-layer SIW feeding network is designed and tested to illustrate this technique. The results manifest that the planar integrated antenna array features adjustable polarization with considerable gain. Furthermore, a two-layer scheme of orthogonal SIW feeding is developed, which would provide a more flexible topology for the scale-expandable array antenna with adjustable polarizations.
Autors: Fengchao Ren;Wei Hong;Ke Wu;Dan Yu;Yangtao Wan;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 6167 - 6172
Publisher: IEEE
 
» Poly-Si-Based Physical Unclonable Functions
Abstract:
Physically unclonable functions (PUFs) were introduced over a decade ago for a variety of security applications. Silicon PUFs exploit uncontrollable random variations from manufacturing to generate unique and random signatures/responses. However, such sources of randomness may become limited during standard CMOS manufacturing as processes continue to mature especially with the advances in design for manufacturability. Recently, poly-Si is proposed to improve PUF quality by offering considerable random variations at the materials level, which is from randomly distributed grain boundaries and trapped charges in poly-Si. In this paper, we develop a poly-Si field-effect transistor (FET) model to study the properties of poly-Si-based PUFs under different supply voltages () and temperatures (). Simulation results obtained from ring oscillator and arbiter PUFs show that compared with conventional CMOS-based PUFs, the reliability of poly-Si-based PUFs can be improved from around 90% to 98% and the PUF devices are robust against varying and .
Autors: Haoting Shen;Fahim Rahman;Bicky Shakya;Xiaolin Xu;Mark Tehranipoor;Domenic Forte;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Nov 2017, volume: 25, issue:11, pages: 3207 - 3217
Publisher: IEEE
 
» POSEIDON: An Analytical End-to-End Performance Prediction Model for Submerged Object Detection and Recognition by Lidar Fluorosensors in the Marine Environment
Abstract:
An analytical end-to-end model is developed to predict the performance of underwater object recognition by means of light detection and ranging (lidar) fluorosensors, as an aid to underwater lidar mission planning and system design. The proposed Performance prediction mOdel for Submerged object dEtection and recognitIon by liDar fluOrosensors in the marine eNvironment (POSEIDON) reproduces the overall end-to-end fluorescence lidar system chain—from signal generation, to signal propagation, acquisition, and processing. The goal is assessing the performance that may be obtained for spectral recognition of an underwater object in various operational scenarios in terms of several different performance metrics. In addition to the performance prediction models developed in the literature for airborne lidar bathymetry, POSEIDON embeds a novel comprehensive signal simulator that accounts for inelastic scattering phenomena as well as a signal processing module designed ad hoc to accomplish spectral recognition of an underwater object with respect to a data base of objects of interest spectrally characterized by their fluorescence spectral signatures. Test cases with a lidar system arranged in two configurations and several objects submerged at various depths in different Cases I and II waters were reproduced and explored. Results obtained within a Monte Carlo simulation framework provide proof-of-concept of POSEIDON performance forecasting capabilities for underwater object recognition.
Autors: Stefania Matteoli;Laura Zotta;Marco Diani;Giovanni Corsini;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Nov 2017, volume: 10, issue:11, pages: 5110 - 5133
Publisher: IEEE
 
» Potential of Estimating Surface Soil Moisture With the Triangle-Based Empirical Relationship Model
Abstract:
Surface soil moisture (SSM) is a key state variable in controlling land surface energy balance and hydrological process. Based on the mechanism behind land surface temperature (LST)–vegetation index (VI) triangle space, an empirical relationship model has been proposed for SSM estimation with LST, NDVI, and surface albedo, and it has been applied in downscaling the coarse resolution microwave soil moisture product. In this paper, three soil moisture observation networks (REMEDHUS, MAQU, and MURRUMBIDGEE) were selected to evaluate the performance of this model at different climate and land cover conditions with in situ soil moisture measurements and Landsat satellite observations. According to the estimation results from different days for each network, it was found that the model was able to capture SSM variation with a satisfied accuracy [overall root-mean-squared error (RMSE) ranging from 0.025 to 0.055 m3/m3], and the R2 can reach 0.9 on some individual days. However, the performance has high daily variability with some poor ones. The reason is partly attributed to the high sensitivity of the coefficients of the model to the variation degrees of the input LST, normalized difference vegetation index (NDVI), and SSM. Meanwhile, the spatial scale differences between the point measurement and satellite footprint observation are another important issue. To improve the model performance, a new relationship model was proposed by introducing the modified normalized difference water index, and the estimation results had a pronounced improvement (overall RMSE ranging from 0.021 to 0.049 m3/m3) compared with the previous model. The application effect of the proposed model showed that the model coefficient calibration accuracy greatly determined the uncertainty level of the estimation results.
Autors: Wei Zhao;Ainong Li;Tianjie Zhao;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6494 - 6504
Publisher: IEEE
 
» Potentiality of Density-Functional Theory in Analyzing the Devices Containing Graphene-Crystalline Solid Interfaces: A Review
Abstract:
Graphene-based devices have initiated unprecedented breakthrough in nanoelectronics. Due to its intrinsic ultrathin 2-D nature, the unique structural, mechanical, electronic, optical, and magnetic properties of graphene are found to be extremely dependent on its substrate material. For the synthesis of graphene with pretailored features or fabrication of graphene-based device with tunable functionality, understanding of the graphene interfaces with other materials are of pivotal importance. Density-functional theory (DFT) computations have been proved to be a powerful tool in investigating the interface properties of graphene-crystalline solids and to subsequently correlate the experimental findings with underlying mechanisms, as well as to explore their potential applications. This paper presents a comprehensive review on utility of DFT-based analysis for graphene interfaces/heterostructures with other crystalline solid materials including metals, semiconductors, and insulators. DFT computational efforts to choose the appropriate material for substrate catalyst, probe, and electrode in graphene synthesis/graphene-based nanodevice design have been critically reviewed including the investigation of different combination of complex interfaces as well as unconventional materials. Salient features, advantages, and constraints of the approach have also been summarized.
Autors: K. Ghosh;H. Rahaman;Partha Bhattacharyya;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4738 - 4745
Publisher: IEEE
 
» Power Control for Energy Efficient D2D Communication in Heterogeneous Networks With Eavesdropper
Abstract:
In general heterogeneous networks, the interference from other communication systems is a main factor for degrading the performance in terms of data rate, so that each system is required to minimize the interference to other systems. However, if the eavesdropper is additionally considered in the heterogeneous networks, the signal from other systems can be utilized for disturbing the information recovery of the eavesdropper. Based on this idea and the importance of the energy efficient communication in Internet of Things (IoT) system, we propose a power control scheme for improving the energy efficiency of device-to-device communication while assisting the secure communication of wireless local area network by interfering with the eavesdropper. We derive a closed-form expression for an optimal power control factor as a function of system parameters. The simulation results confirm the accuracy of analysis and show that the proposed scheme outperforms the conventional scheme in terms of the energy efficiency.
Autors: Kisong Lee;Jun-Pyo Hong;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2536 - 2539
Publisher: IEEE
 
» Power Electronics in Smart Grid and Renewable Energy Systems [Scanning the Issue]
Abstract:
The special issue presents the state of the art and offers perspectives on future developments in the area of power electronics through applications-oriented reviews and tutorials.I am proudly presenting this special issue to the professional communities of the world. Power electronics is an extremely important element in modern smart grid and renewable energy systems. Basically, it uses high-efficiency switching power semiconductor devices to convert and control electrical power with the help of dc-to-dc, dc-to-ac, ac-to-dc, and ac-to-ac converters that are applied extensively in industrial, commercial, residential, transportation, aerospace, military, and utility systems. Power electronics plays significant role in modern industrial automation and high-efficiency energy systems that include renewable energy systems (such as wind and photovoltaic), bulk energy storage, electric and hybrid vehicles, and energy-efficiency improvement of electrical equipment. In modern electric power grid, power electronics is indispensable in high-voltage dc (HVDC) system, static VAR compensators (SVCs), flexible ac transmission system (FACTS)-based active and reactive power flow control, uninterruptible power system (UPS), fuel-cell-based energy system, etc. After a dynamic technology evolution for nearly five decades, power electronics has now grown possibly as the most important technology in the 21st century. Currently, most of our energy comes from fossil fuels and nuclear power plants. Fossil fuels cause environmental pollution that causes global warming or climate change problems. Nuclear energy is clean in that respect, but it has safety and radioactive waste disposal problems. For these reasons, the whole world is now turning toward renewable energy, where power electronics is an indispensable ingredient.
Autors: Bimal K. Bose;
Appeared in: Proceedings of the IEEE
Publication date: Nov 2017, volume: 105, issue:11, pages: 2007 - 2010
Publisher: IEEE
 
» Power Electronics, Smart Grid, and Renewable Energy Systems
Abstract:
The paper is basically an introduction of power electronics and its applications with emphasis on renewable energy systems and smart grid. The advent of modern power electronics has brought tremendous impact on power systems, besides the usual industrial applications to improve productivity. Power electronics is possibly the most important element in modern smart grid and renewable energy systems. The discussion in the paper will include modern power semiconductor devices and applications of power electronics in energy saving, electric vehicles, renewable energy systems, and grid energy storage. Finally, the basic elements of smart grid will be reviewed.
Autors: Bimal K. Bose;
Appeared in: Proceedings of the IEEE
Publication date: Nov 2017, volume: 105, issue:11, pages: 2011 - 2018
Publisher: IEEE
 
» Power Generation Properties of Flow Nanogenerator With Mixture of Magnetic Nanofluid and Bubbles in Circulating System
Abstract:
A method has been developed for demonstrating a flow nanogenerator by using a mixture of magnetic nanofluid (MNF) and bubbles in a fluid circulating system, and notable phenomena related to the power generation properties of the nanogenerator have been explored. MNF is widely used in various areas because of its interesting magnetic properties under an external magnetic field. The objective of the proposed technique is to obtain the induced electromotive force (EMF) based on Faraday’s law due to the flow of MNF in a closed-circulating system. To maximize the induced EMF, magnetic nanoparticles (MNPs) should pass through the induction coil with a perpendicular magnetization direction in accordance with Faraday’s law. To control the magnetization direction of the MNPs, a permanent magnet was employed to produce an external magnetic field that considers the Brownian and Néel motions. To obtain a continuously induced voltage, a circulation system was implemented ensuring the flow of the MNF in the closed cycle. Further, power generation properties were investigated considering electric, magnetic, and fluidic effects. To analyze this complicated physics, a multiphysics analysis was used to calculate the flow pattern of the MNF according to its magnetic properties, and the acquired results were compared with those obtained from the experiment. From these experiments, we investigated the generation properties of the nanogenerator considering the flowrate of the MNF as well as the presence or absence of bubbles within the MNF. Our experimental tests demonstrated that the continuous power generation mode was successfully achieved with a mixture of MNF and bubbles.
Autors: Su-Hun Kim;Jong-Hoo Park;Hong-Soon Choi;Se-Hee Lee;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Power Semiconductor Devices for Smart Grid and Renewable Energy Systems
Abstract:
Modern civilization is related to the increased use of electric energy for industry production, human mobility, and comfortable living. Highly efficient and reliable power electronic systems, which convert and process electric energy from one form to the other, are critical for smart grid and renewable energy systems. The power semiconductor device, as the cornerstone technology in a power electronics system, plays a pivotal role in determining the system efficiency, size, and cost. Starting from the invention and commercialization of silicon bipolar junction transistor 60 years ago, a whole array of silicon power semiconductor devices have been developed and commercialized. These devices enable power electronics systems to reach ultrahigh efficiency and high-power capacity needed for various smart grid and renewable energy system applications such as photovoltaic (PV), wind, energy storage, electric vehicle (EV), flexible ac transmission system (FACTS), and high voltage dc (HVDC) transmission. In the last two decades, newer generations of power semiconductor devices based on wide bandgap (WBG) materials, such as SiC and GaN, were developed and commercialized further pushing the boundary of power semiconductor devices to higher voltages, higher frequencies, and higher temperatures. This paper reviews some of the major power semiconductor devices technologies and their potential impacts and roadmaps.
Autors: Alex Q. Huang;
Appeared in: Proceedings of the IEEE
Publication date: Nov 2017, volume: 105, issue:11, pages: 2019 - 2047
Publisher: IEEE
 
» Power Sharing in Angle Droop Controlled Microgrids
Abstract:
Component mismatches and parameters drifts drastically affect stability and long-term operation of droop-controlled inverter-based microgrids. This paper analyzes and illustrates the impact of design variations and parameter drifts between angle droop controlled inverter-interfaced sources in a microgrid. It is shown that microgrid stability is very sensitive to parameter drifts, especially in frequency. A coordination control scheme that uses internode communications is proposed for improving the stability margin and ensuring the desired power sharing. Conditions for stability are derived and simulation results are presented to validate the performance of the proposal.
Autors: Ramachandra Rao Kolluri;Iven Mareels;Tansu Alpcan;Marcus Brazil;Julian de Hoog;Doreen Anne Thomas;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4743 - 4751
Publisher: IEEE
 
» Power Spectrum Computation for an Arbitrary Phase Noise Using Middleton’s Convolution Series: Implementation Guideline and Experimental Illustration
Abstract:
In this paper, we revisit the convolution series initially introduced by Middleton several decades ago to determine the power spectrum (or spectral line shape) of a periodic signal from its phase noise power spectral density. This topic is of wide interest, as it has an important impact on many scientific areas that involve lasers and oscillators. We introduce a simple guideline that enables a fairly straightforward computation of the power spectrum corresponding to an arbitrary phase noise. We show the benefit of this approach on a computational point of view, and apply it to various types of experimental signals with different phase noise levels, showing a very good agreement with the experimental spectra. This approach also provides a qualitative and intuitive understanding of the power spectrum corresponding to different regimes of phase noise.
Autors: Pierre Brochard;Thomas Südmeyer;Stéphane Schilt;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Nov 2017, volume: 64, issue:11, pages: 1766 - 1775
Publisher: IEEE
 
» Pragmatic Modeling of Dynamic Magnetization and Iron Loss in Grain-Oriented Steel Sheets
Abstract:
This paper presents the extension of two 1-D lamination models with magnetic hysteresis to reproduce dynamic hysteresis loops and power loss in grain-oriented (GO) electrical steels. For this purpose, the concept of magnetic viscosity is introduced in the model equations. The applicability and accuracy are demonstrated by means of two GO steels of different thicknesses at magnetizing frequencies up to 1000 Hz. Advantages and limits of the classical approach with and without viscosity and comparisons to measured data are discussed in detail.
Autors: M. Petrun;S. Steentjes;K. Hameyer;B. Polajžer;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Pre-Capture Privacy for Small Vision Sensors
Abstract:
The next wave of micro and nano devices will create a world with trillions of small networked cameras. This will lead to increased concerns about privacy and security. Most privacy preserving algorithms for computer vision are applied after image/video data has been captured. We propose to use privacy preserving optics that filter or block sensitive information directly from the incident light-field before sensor measurements are made, adding a new layer of privacy. In addition to balancing the privacy and utility of the captured data, we address trade-offs unique to miniature vision sensors, such as achieving high-quality field-of-view and resolution within the constraints of mass and volume. Our privacy preserving optics enable applications such as depth sensing, full-body motion tracking, people counting, blob detection and privacy preserving face recognition. While we demonstrate applications on macro-scale devices (smartphones, webcams, etc.) our theory has impact for smaller devices.
Autors: Francesco Pittaluga;Sanjeev Jagannatha Koppal;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Nov 2017, volume: 39, issue:11, pages: 2215 - 2226
Publisher: IEEE
 
» Precise Measurement of Fiber Third-Order Dispersion Using Transfer Function of a Microwave Photonic Filter
Abstract:
Third-order dispersion (TOD) is a fundamental parameter to characterize optical fiber. In this paper, we propose a method to precisely measure TOD of an optical fiber by using the amplitude and phase transfer function of a microwave photonic filter (MPF). The fiber under test (FUT) plays an important role in the MPF, of which the transfer function has a quadratic phase distortion due to the TOD of the FUT. Through iteratively modifying the quadratic phase spectral coefficient of the optical signal in the MPF to counteract the TOD effect, the transfer function distortion can be almost compensated. According to the definite relationship between the TOD and the compensation coefficient, we can determine the TOD precisely. In the experiment, the measurement uncertainty of 0.2% is obtained of a dispersion compensating fiber, designed for the compensation of 80 km standard fiber.
Autors: Yurong Gao;Shangyuan Li;Xiaoxiao Xue;Xiaoping Zheng;Hanyi Zhang;Bingkun Zhou;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:22, pages: 4865 - 4870
Publisher: IEEE
 
» Precise Optical Modulation Using Extinction-Ratio and Chirp Tunable Single-Drive Mach–Zehnder Modulator
Abstract:
We analyzed the complex transfer function and modulation spectrum of the Mach–Zehnder (MZ) modulator with optical power and phase change imbalances. From the calculations, we found that the characteristic operation can be obtained in three cases: high extinction ratio, zero-chirp, and straight-line trajectory in the IQ plane. However, the results also indicate that we cannot achieve an operation equivalent to that of the ideal modulator, due to the small parasitic chirp in a single-drive modulator. To control the extinction ratio and chirp parameter individually, we propose an integrated modulator with some tunable Y-branches. By using the optical-power-imbalance tunable modulators, we experimentally demonstrate the characteristic operations and obtain the modulation spectrum equivalent to the ideal MZ modulator. However, compared to the ideal amplitude modulator, MZ modulators exhibit an intrinsic nonlinearity in the sinusoidal response. Therefore, we used a third-order nonlinearity compensation method using the superposition of electrical third-order harmonics. The measured spectrum consisted of only first-order modulation sidebands, which is equivalent to the ideal double-sideband suppressed-carrier modulation.
Autors: Yuya Yamaguchi;Atsushi Kanno;Tetsuya Kawanishi;Masayuki Izutsu;Hirochika Nakajima;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4781 - 4788
Publisher: IEEE
 
» Precoding-Aided Spatial Modulation With Increased Robustness to Channel Correlations
Abstract:
We present a precoding approach for spatial modulation (SM) for increased robustness against spatial correlations over slow fading Rayleigh channels. This approach, based on phase-rotation of the transmitted symbol according to the active transmit antenna, can be implemented without changing the power budget or needing any explicit knowledge of the channel state information at the transmitter. The optimum precoding coefficients are determined so as to minimize the asymptotic average bit-error rate. Both theoretical analysis and simulation results indicate significant performance improvements even in the case of heavily correlated transmit antennas.
Autors: Mutlu Koca;Hikmet Sari;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2388 - 2391
Publisher: IEEE
 
» Predicting Popularity of Online Videos Using Support Vector Regression
Abstract:
In this work, we propose a regression method to predict the popularity of an online video measured by its number of views. Our method uses Support Vector Regression with Gaussian radial basis functions. We show that predicting popularity patterns with this approach provides more precise and more stable prediction results, mainly thanks to the nonlinear character of the proposed method as well as its robustness. We prove the superiority of our method against the state of the art using datasets containing almost 24 000 videos from YouTube and Facebook. We also show that using visual features, such as the outputs of deep neural networks or scene dynamics' metrics, can be useful for popularity prediction before content publication. Furthermore, we show that popularity prediction accuracy can be improved by combining early distribution patterns with social and visual features and that social features represent a much stronger signal in terms of video popularity prediction than the visual ones.
Autors: Tomasz Trzciński;Przemysław Rokita;
Appeared in: IEEE Transactions on Multimedia
Publication date: Nov 2017, volume: 19, issue:11, pages: 2561 - 2570
Publisher: IEEE
 
» Predicting Temporal Social Contact Patterns for Data Forwarding in Opportunistic Mobile Networks
Abstract:
In this paper, we predict nodes’ social contact patterns from the temporal perspective, and propose a novel approach to improve the performance of data forwarding in opportunistic mobile networks (OMNs). Specifically, considering both the average separating time and the variance of the separating time, we first introduce the definition of temporal closeness and temporal centrality. Then, several intuitive prediction methods are designed to predict nodes’ future temporal social contact patterns based on the observations from extensive real trace-driven simulation results. Afterward, based on the predicted temporal social contact patterns, we propose an efficient temporal closeness and centrality-based data forwarding strategy named TCCB for OMNs. The core idea of TCCB is to capture and utilize the temporal correlations to infer the future temporal social contact patterns in the remaining valid time of the data. Finally, extensive real trace-driven simulations are conducted to evaluate the performance of TCCB. The results show that TCCB is close to Epidemic in terms of delivery ratio but with significantly reduced delivery cost. Furthermore, TCCB performs much better than Bubble Rap and Prophet in terms of delivery ratio, but the delivery cost of TCCB is very close to that of Bubble Rap.
Autors: Huan Zhou;Victor C. M. Leung;Chunsheng Zhu;Shouzhi Xu;Jialu Fan;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10372 - 10383
Publisher: IEEE
 
» Prediction of Nonlinear Distortion in Wideband Active Antenna Arrays
Abstract:
In this paper, we propose a technique for comprehensive analysis of nonlinear and dynamic characteristics of multi-antenna transmitters (TXs). The analysis technique is enabled by the development of a Volterra series-based dual-input model for power amplifiers (PAs), which is capable of considering the joint effects of PA nonlinearity, antenna crosstalk, and mismatch for wideband modulated signals. By combining multiple instances of the PA model with linear dynamic antenna simulations, we develop the analysis technique. The proposed method allows the prediction of the output signal of every antenna in an arbitrarily sized TX array, as well as the total far-field radiated wave of the TX for any input signal with low computational effort. A 2.12-GHz four-element TX demonstrator based on GaAs PAs is implemented to verify simulation results with measurements. The proposed technique is a powerful tool to study hardware characteristics as, for example, the effects of antenna design and element spacing. It can be used in cases where experiments are not feasible, and thus aid the development of next generation wireless systems.
Autors: Katharina Hausmair;Sebastian Gustafsson;César Sánchez-Pérez;Per N. Landin;Ulf Gustavsson;Thomas Eriksson;Christian Fager;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Nov 2017, volume: 65, issue:11, pages: 4550 - 4563
Publisher: IEEE
 
» Prediction of the Transient Stability Boundary Based on Nonparametric Additive Modeling
Abstract:
This paper applies modern statistical nonparametric methodology to the problem of prediction of the transient stability boundary of large-scale power engineering systems. The stability issue is characterized by the critical clearing time (CCT) that is employed to determine whether a precontingency steady-state condition is stable for a given fault in the power system. The multidimensional mapping between the precontingency steady-state conditions and the corresponding CCT is modeled as an additive structure of one-dimensional functions. Nonparametric kernel estimation methods are applied to the assumed additive model yielding the boundary prediction algorithm that is easily interpretable and avoids the curse of dimensionality. The precision of our additive nonlinear modeling is demonstrated in the context of fault prediction of the 470-bus power network. For the specified fault type, we demonstrate a stronger prediction accuracy compared to other large-scale machine learning methods that have been used for the transient stability boundary problem so far.
Autors: Jiaqing Lv;Mirosław Pawlak;U. D. Annakkage;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4362 - 4369
Publisher: IEEE
 
» Predictive Energy Management Strategy for Fully Electric Vehicles Based on Preceding Vehicle Movement
Abstract:
This paper presents an energy-efficient and terrain-information-and-preceding-vehicle-information-incorporated energy management strategy for fully electric vehicles (FEVs) equipped with in-wheel motors. Saving driving energy with terrain preview and preceding vehicle movement prediction are crucial to prolong the driving distance for an FEV. Unlike conducting energy optimization under the assumption that the preceding vehicle movements are already known in most studies, the front vehicle movements are predicted during each control cycle based on the vehicle-to-vehicle communication, and the FEV vehicle velocity and motor torque distribution are optimized by a nonlinear model predictive controller to reduce energy consumption. The energy-saving objective is achieved by including, in the cost function, the motor energy consumption in each control cycle, while the safety objective is accomplished by keeping a suitable relative distance from the preceding vehicle. Since the nonlinear vehicle longitudinal model is applied, the gridding initial torque plane is utilized in each time step to search for the global minimum. Simulation results show that this method has a better energy-saving performance than the control method without using the preceding vehicle movement information, and the algorithm proposed here has a wide applicability under various driving conditions.
Autors: Shuwei Zhang;Yugong Luo;Junmin Wang;Xiao Wang;Keqiang Li;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Nov 2017, volume: 18, issue:11, pages: 3049 - 3060
Publisher: IEEE
 
» Pricing and Rate Optimization of Cloud Radio Access Network Using Robust Hierarchical Dynamic Game
Abstract:
We develop a robust one-leader multi-follower dynamic linear quadratic game for 5G wireless networks with a cloud radio access network setting. The network consists of a baseband unit (BBU) owner and multiple remote radio heads (RRHs). The users’ traffic from the RRH is routed to BBUs based on their price and congestion which is modeled as a dynamic difference equation, considering the effect of decisions taken by the RRHs, price, and uncertainties. In the proposed dynamic game, the BBU owner is the leader and the RRHs are the followers. The uncertainties raised from compression noise and link imperfection, such as packet loss, is modeled as an exogenous disturbance to the system. The equilibrium point of the proposed robust hierarchical dynamic game is achieved, and the conditions for the existence and uniqueness of the equilibrium point are provided in two cases, including unconstrained problem and also by considering the fronthaul constraints. Finally, the simulation results show the advantages in terms of cumulative payoff compared with other existing baseline schemes.
Autors: Mohsen Saffar;Hamed Kebriaei;Dusit Niyato;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7404 - 7418
Publisher: IEEE
 
» Primal and Dual Generalized Eigenvalue Problems for Power Systems Small-Signal Stability Analysis
Abstract:
The paper presents a comprehensive study of small-signal stability analysis of power systems based on matrix pencils and the generalized eigenvalue problem. Both primal and dual formulations of the generalized eigenvalue problem are considered and solved through a variety of state-of-the-art solvers. The paper also discusses the impact on the performance of the solvers of two formulations of the equations modelling the power systems, namely, the explicit and semi-implicit form of differential-algebraic equations. The case study illustrates the theoretical aspects and numerical features of these formulations and solvers through two real-world systems, namely, a 1,479-bus model of the all-island Irish system, and a 21,177-bus model of the ENTSO-E network.
Autors: Federico Milano;Ioannis Dassios;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4626 - 4635
Publisher: IEEE
 
» Principal Graph and Structure Learning Based on Reversed Graph Embedding
Abstract:
Many scientific datasets are of high dimension, and the analysis usually requires retaining the most important structures of data. Principal curve is a widely used approach for this purpose. However, many existing methods work only for data with structures that are mathematically formulated by curves, which is quite restrictive for real applications. A few methods can overcome the above problem, but they either require complicated human-made rules for a specific task with lack of adaption flexibility to different tasks, or cannot obtain explicit structures of data. To address these issues, we develop a novel principal graph and structure learning framework that captures the local information of the underlying graph structure based on reversed graph embedding. As showcases, models that can learn a spanning tree or a weighted undirected graph are proposed, and a new learning algorithm is developed that learns a set of principal points and a graph structure from data, simultaneously. The new algorithm is simple with guaranteed convergence. We then extend the proposed framework to deal with large-scale data. Experimental results on various synthetic and six real world datasets show that the proposed method compares favorably with baselines and can uncover the underlying structure correctly.
Autors: Qi Mao;Li Wang;Ivor W. Tsang;Yijun Sun;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Nov 2017, volume: 39, issue:11, pages: 2227 - 2241
Publisher: IEEE
 
» Privacy-Aware Blind Cloud Framework for Advanced Healthcare
Abstract:
This letter proposes a novel privacy-aware “blind” cloud infrastructure to be utilized for storage, processing, and organization of health data. Traditional healthcare systems rely on cloud computing servers for back-end storage and processing. However, cloud servers are heavily vulnerable to privacy threats and the problem is even more intense as physiological data carry sensitive information. To resolve the aforementioned issue, this letter proposes the blind cloud framework. The goal is to take advantage of the enormous computing and storage abilities of the cloud servers, and yet maintain data anonymity simultaneously. To preserve the privacy of the medical data, the cloud server is forcefully blinded, i.e., the identities of the patients are masked off and a pseudo-identity is generated, thereby, obtaining unidentified in-cloud data for storage and analysis. We also propose a parallel method to be executed within the non-cloud servers for efficient and lossless identity management and retrieval. Results indicate that the performance of the processes of pseudo-identity generation and identity retrieval is independent of the data volumes, and negligibly vary with the increase in the number of the clients of the system.
Autors: Subhadeep Sarkar;Subarna Chatterjee;Sudip Misra;Rajesh Kudupudi;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2492 - 2495
Publisher: IEEE
 
» Probabilistic Analysis of Electronic Systems via Adaptive Hierarchical Interpolation
Abstract:
We present a framework for system-level analysis of electronic systems whose runtime behaviors depend on uncertain parameters. The proposed approach thrives on hierarchical interpolation guided by an advanced adaptation strategy, which makes the framework general and suitable for studying various metrics that are of interest to the designer. Examples of such metrics include the end-to-end delay, total energy consumption, and maximum temperature of the system under consideration. The framework delivers a light generative representation that allows for a straightforward, computationally efficient calculation of the probability distribution and accompanying statistics of the metric at hand. Our technique is illustrated by considering a number of uncertainty-quantification problems and comparing the corresponding results with exhaustive simulations.
Autors: Ivan Ukhov;Petru Eles;Zebo Peng;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Nov 2017, volume: 36, issue:11, pages: 1883 - 1896
Publisher: IEEE
 
» Probabilistic Network Coding Based on Buyer/Seller Games for Retransmissions in Wireless Networks
Abstract:
In wireless networks, retransmissions are used by senders to recover lost packets. The conventional retransmission schemes usually retransmit only one lost packet each time, resulting in a low retransmission efficiency. However, using broadcasting nature of a wireless channel with network coding (NC), we can recover more than one lost packet per transmission. Different from single-sender multiple-receiver wireless networks as considered in the existing works, this paper explores the ways to use NC for retransmissions in multiple-sender multiple-receiver scenarios. In addition, this paper also aims to investigate the advantages and shortcomings of using NC in retransmissions. In order to maximize the gain and minimize the impact in NC retransmissions, a probabilistic network coding retransmission (PNCR) scheme is proposed, where a buyer/seller game-theoretic approach is adopted to optimize the performance. The experimental results confirm the effectiveness of the PNCR scheme.
Autors: Bin Cao;Li Qiao;Yun Li;Chonggang Wang;Hsiao-Hwa Chen;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10406 - 10418
Publisher: IEEE
 
» Product Transformation and Heuristic EXOR-AND-OR Logic Synthesis of Incompletely Specified Functions
Abstract:
Previously, the synthesis of reversible and quantum permutative circuits based on products of Exclusive-OR (EXOR) sums of inputs (POE) was explored as an approach to reduce quantum cost. Herein, the mathematical representation used in POE expressions is formally detailed and contrasted with the pseudoproduct-based theory of Luccio and Pagli. The theory and practice of product transformation, or computation of equivalent POE expressions, is presented. To demonstrate the generality of the mathematical representations outside of the reversible domain, a new method to synthesize incompletely specified functions as EXOR-AND-OR circuits is introduced. The method is heuristic. It first uses spectral information from the Walsh–Hadamard transform to compute a set of POE implicants for a function, and then uses product transformation to minimize both the total number of literals and unique EXOR sums (ignoring polarity) used in the POE implicants. The product transformation minimization extends to multioutput functions. The new method has no performance guarantees, i.e., it does not have a fallback mode of minimum or near-minimum sum of products; therefore, it is suited to a tournament synthesis approach. When synthesizing benchmark functions of up to 26 inputs, the new method is shown to typically produce lower cost circuits than heuristic pseudoproduct-based methods.
Autors: Ben Schaeffer;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Nov 2017, volume: 36, issue:11, pages: 1831 - 1841
Publisher: IEEE
 
» Programming the World
Abstract:
Computing evolution has brought about multiple paradigm shifts in how we use technologies. In the living laboratory that is modern life, our ability to design and control the computers and computing power of the future will require an ability to program systems and applications in situ and in vivo.
Autors: Michael Beigl;Florian Michahelles;Hide Tokuda;Steve Hodges;
Appeared in: Computer
Publication date: Nov 2017, volume: 50, issue:11, pages: 14 - 17
Publisher: IEEE
 
» Proposal of Thickness Measurement Method of Steel Plate With High Liftoff Using Pulsed Magnetic Field
Abstract:
As for the steel tube for liquefied natural gas in a petrochemical plant, the steel tube with a large diameter is covered with the thermal insulation material and the sheet metal. Generally, the thickness of its thermal insulation material is about 80 mm. On the inspection of the thickness or the corrosion in this steel tube, the sheet metal and the thermal insulation material are removed from the steel tube. However, much cost and time are needed for this inspection. In this paper, the pulse electromagnetic inspection method for detecting the defect in the steel tube from the upper side of the insulation material and the sheet metal is proposed. The defect is inspected by measuring the slope of the output voltage from the maximum output voltage value obtained immediately after cutting off the pulse wave magnetic field. In addition, the proposed inspection method is investigated by the 3-D nonlinear finite-element method taking into account hysteresis magnetizing properties and eddy current in the steel tube.
Autors: Saijiro Yoshioka;Yuji Gotoh;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Pt Gate Sink-In Process Details Impact on InP HEMT DC and RF Performance
Abstract:
A Pt/Ti/Pt/Au gate electrode stack is commonly used in AlInAs/GaInAs/InP high electron mobility transistors due to the high Schottky barrier height of Pt on AlInAs and the fact that Pt can be controllably diffused through semiconductor layers thereby enabling vertical scaling. We show here that the Pt-AlInAs reaction is not only controlled by the annealing time and temperature—the annealing ambient and the thermal ramp rate also affect the diffusion of Pt through the underlying semiconductor layers and impact the DC and RF device performance. Following the gate metal deposition, one process split was rapid thermal annealed at 250 °C and subsequently passivated by atomic layer deposition (ALD) at 180 °C. For the second process split, the Pt gate sink-in process was carried out in the ALD system at 250 °C simultaneously with the gate passivation. Despite identical gate sink-in temperatures, the two process splits exhibit different characteristics suggesting different gate-to-channel distances. The distance of the Pt gate to the GaInAs channel was therefore confirmed through high-resolution cross-sectional scanning transmission electron microscopy analysis. The results presented here reveal that both the suitable ramp rate and the sink-in ambient are necessary to achieve a fully sunken Pt gate.
Autors: Tamara Saranovac;Anna Hambitzer;Diego C. Ruiz;Olivier Ostinelli;C. R. Bolognesi;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 462 - 467
Publisher: IEEE
 
» QoS Provisionings for Device-to-Device Content Delivery in Cellular Networks
Abstract:
Device-to-device (D2D) technique provides a feasible way for content delivery among proximal users without deploying additional infrastructures. For the realization of D2D content delivery, it is important to guarantee quality-of-service (QoS) for supporting real-time content transmissions. In this paper, we formulate the content delivery problem based on a flow model and investigate mechanisms providing delay QoS guarantee. The delay performance is analyzed for the content dissemination with the aid of D2D communication. Based on the analyses of parameters affecting the performance of content delivery, an optimal resource allocation scheme is proposed to achieve the best energy efficiency of content delivery in cellular networks with guaranteed delay constraints for hybrid content requests. Then effects of content caching on D2D content delivery is studied and a caching management scheme is proposed to avoid cache overflow of users with a certain probability and satisfy QoS requirements of content delivery. Simulation results are presented that verify the analyzed influencing factors on D2D content delivery and the proposed QoS-provisioning schemes.
Autors: Yanli Xu;Feng Liu;
Appeared in: IEEE Transactions on Multimedia
Publication date: Nov 2017, volume: 19, issue:11, pages: 2597 - 2608
Publisher: IEEE
 
» QoS-Based Binary Signature Design for Secure CDMA Systems
Abstract:
Physical layer security, aiming at preventing the confidential information from eavesdroppers, has drawn significant attentions in recent years. In this paper, we address the problem of securing downlink single-user and multiuser transmissions in code division multiple-access systems. Particularly, we propose a novel binary signature design method to minimize the reception of the confidential messages at the eavesdropper. The popular signal-to-interference-plus-noise ratio (SINR) metric is adopted as a pragmatic security performance measurement. Specifically, for securing the single-user transmission, we aim to design a binary signature to minimize the eavesdropper's SINR while maintain the legitimate user's SINR at a desired level. However, the optimal exhaustive searching method has complexity growing exponentially with the signature length. Thus, we propose two suboptimal low-complexity semi-definite relaxation (SDR)-based and Rayleigh-quotient-based binary signature design algorithms, which have near optimal performance with much lower computational complexity. Furthermore, we extend the findings in the single-user case to multiuser scenario. Particularly, we propose to design a set of quasi-orthogonal signatures based on eavesdropping channel and select the conditionally optimal binary signature for each user iteratively until convergence. Simulation studies confirm our analytical performance predictions and demonstrate the benefits of the proposed secure signature design algorithms.
Autors: Ming Li;Guangyu Ti;Xiaowen Tian;Qian Liu;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10011 - 10023
Publisher: IEEE
 
» Quadratic Magneto-Optic Kerr Effect Investigations of Fe(100) Grown on Ir(100)
Abstract:
Magneto-optic Kerr effect (MOKE) is a widely used tool in surface physics to characterize magnetic thin films and single crystals. In most of its applications, the magneto-optic (MO) coupling is assumed to be linear on magnetization by neglecting the quadratic and higher dependences. However, recent observations have shown that the quadratic dependence cannot be always ignored, particularly in systems like ferromagnetic metal thin films, Heusler alloys, and even in half-metallic ferrimagnets. We have used a rotating field method to extract the QMOKE signal from Fe(100) film grown on (100) surface of a single crystal iridium. Our results show that the QMOKE signal from this system is comparable to the linear MOKE signal. We report the parameters L, b, and c which relate the linear (K) and quadratic (G and ) MO coupling coefficients. The real part of L, b, and c obtained from Fe(100)/Ir(100) are −9.75 ± 0.03 mdeg, 7.28 ± 0.09 mdeg, and −5.0 ± 0.1 mdeg, respectively.
Autors: A. V. Pradeep;Sayak Ghosh;K. G. Ajesh;P. S. Anil Kumar;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Quadruple Butterfly Coil With Passive Magnetic Shielding for Focused Transcranial Magnetic Stimulation
Abstract:
Coil design for transcranial magnetic stimulation (TMS) is a critical factor that is constantly being investigated to provide more focused stimulation of the brain. The design of focal coils is important because TMS uses time-varying magnetic fields generated from electromagnetic coils to stimulate a specific region of interest of the brain non-invasively. TMS is a useful tool in both diagnostic and therapeutic purposes for identifying and treating psychiatric and neurological disorders. Currently, TMS is approved by the U.S. Food and Drug Administration for the treatment of chronic depression and is being researched for the treatment of stroke, obsessive compulsive disorder, post-traumatic stress disorder, and Parkinson’s disease. In this paper, the authors are proposing to further improve the focality of the quadruple butterfly coil (QBC) by using a high-permeability ferromagnetic material acting as passive magnetic shield. Analyses of the resulting field profiles with 50 heterogeneous head models using a single and double magnetic shield has been conducted at two different positions in the brain: the vertex and the dorsolateral prefrontal cortex. Comparison of the results has been illustrated with the help of QBC and figure-8 coil by using parameters of interest such as maximum electric field intensities in both the brain and the entire head, the volume of the brain receiving strong stimulation intensities, and the surface area of the brain receiving strong stimulation intensities. There is a significant amount of improvement found in focality when the QBC is used with a magnetic shield. With a shield, the coil is still able to maintain a comparable maximum electric field intensity in the targeted region of the brain to that of the original QBC. Although both shielding solutions show significant improvement, no notable difference has been found in the results between single and double shields with the QBC.
Autors: Priyam Rastogi;Yalun Tang;Bowen Zhang;Erik G. Lee;Ravi L. Hadimani;David C. Jiles;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Quality-Aware Traffic Offloading in Wireless Networks
Abstract:
In cellular networks, due to many practical deployment issues, some areas have good wireless coverage while other areas may not. This results in significant throughput (service quality) difference between wireless carriers at some locations. We first analyze the factors that affect the service quality and then validate the existence of service quality difference between different carriers via extensive measurements. To deal with this problem, a mobile device (node) with low service quality can offload its data traffic to nearby nodes with better service quality through Device-to-Device interfaces, such as WiFi direct, to save energy and reduce delay. To achieve this goal, we propose a Quality-Aware Traffic Offloading (QATO) framework to offload network tasks to neighboring nodes with better service quality. QATO can identify neighbors with better service quality and motivate nodes to help each other using incentive schemes. To validate our design, we have implemented QATO on Android platform and have developed a web browser and a photo uploader on top of it. Experimental results show that QATO can significantly reduce energy and delay for both data downloading and uploading. Through trace-driven simulations, we also show that all users can benefit from data offloading in the long run.
Autors: Wenjie Hu;Guohong Cao;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Nov 2017, volume: 16, issue:11, pages: 3182 - 3195
Publisher: IEEE
 
» Quantifying Net Synergy/Redundancy of Spontaneous Variability Regulation via Predictability and Transfer Entropy Decomposition Frameworks
Abstract:
Objective: Indexes assessing the balance between redundancy and synergy were hypothesized to be helpful in characterizing cardiovascular control from spontaneous beat-to-beat variations of heart period (HP), systolic arterial pressure (SAP), and respiration (R). Methods: Net redundancy/synergy indexes were derived according to predictability and transfer entropy decomposition strategies via a multivariate linear regression approach. Indexes were tested in two protocols inducing modifications of the cardiovascular regulation via baroreflex loading/unloading (i.e., head-down tilt at −25° and graded head-up tilt at 15°, 30°, 45°, 60°, 75°, and 90°, respectively). The net redundancy/synergy of SAP and R to HP and of HP and R to SAP were estimated over stationary sequences of 256 successive values. Results: We found that: 1) regardless of the target (i.e., HP or SAP) redundancy was prevalent over synergy and this prevalence was independent of type and magnitude of the baroreflex challenge; 2) the prevalence of redundancy disappeared when decoupling inputs from output via a surrogate approach; 3) net redundancy was under autonomic control given that it varied in proportion to the vagal withdrawal during graded head-up tilt; and 4) conclusions held regardless of the decomposition strategy. Conclusion: Net redundancy indexes can monitor changes of cardiovascular control from a perspective completely different from that provided by more traditional univariate and multivariate methods. Significance: Net redundancy measures might provide a practical tool to quantify the reservoir of effective cardiovascular regulatory mechanisms sharing causal influences over a target variable.
Autors: Alberto Porta;Vlasta Bari;Beatrice De Maria;Anielle C. M. Takahashi;Stefano Guzzetti;Riccardo Colombo;Aparecida M. Catai;Ferdinando Raimondi;Luca Faes;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Nov 2017, volume: 64, issue:11, pages: 2628 - 2638
Publisher: IEEE
 
» Quantifying Risk of Wind Power Ramps in ERCOT
Abstract:
Hourly wind power ramps in ERCOT are studied by applying extreme value theory. Mean excess plot reveals that the tail behavior of large hourly wind power ramps indeed follows a generalized Pareto distribution. The location, shape, and scale parameters of generalized Pareto distribution are then determined by using mean excess plot and the least square technique, from which risk measures including quantile value at risk and conditional value at risk are calculated.
Autors: Jie Zhao;Sajjad Abedi;Miao He;Pengwei Du;Sandip Sharma;Bill Blevins;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4970 - 4971
Publisher: IEEE
 
» Quantitative Analysis of Magnetic Nanoparticles by Means of Magnetic Force Microscopy
Abstract:
Magnetic force microscopy (MFM) is a powerful and simple tool to analyze magnetic materials and structures down to the nano-meter scale. However, there is still a demand for satisfactory models describing measured MFM data quantitatively, thereby allowing us to quantitatively analyze the magnetic properties of the sample. Here, we present an application of the recently proposed pseudo-pole model, which assumes that the tip can be represented by a cone covered homogeneously with dipoles pointing to the tip of the cone. Nano-composites of ferromagnetic Co nanoparticles (NPs) made by inert gas condensation and subsequently deposited non-magnetic SiOx cover layers with different layer thicknesses on single-crystalline Si substrates have been investigated in this paper. We extract quantitative information about the magnetization of individual NPs, as well as their depth below the surface of the SiOx films. In addition, we present an alternative method to extract information about the NP magnetic moment from the width of the NP signal in lift images, which does not require knowledge about the van der Waals interaction. We find good agreement between the magnetic moments determined by both approaches.
Autors: A. Schillik;R. Shao;U. Herr;B. Koslowski;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Quantitative Design of a High Performance Permanent Magnet Vernier Generator
Abstract:
Permanent-magnet vernier machines are becoming more and more attractive due to their high torque density and low-speed operating capabilities. This paper investigates the effects of the magnet thickness, magnet pole arc ratio, and slot open ratio on the torque capacity. An analytical model is first presented. It is validated by comparing the results with the finite-element analysis (FEA) under the same hypothesis. A mono-objective optimization is then conducted on the basis of the analytical model coupled to genetic algorithm to reach the optimal values yielding the highest value of the torque. Finally, the influence of nonlinear magnetic material behavior on the optimal design is investigated through nonlinear FEA. The results are presented and discussed.
Autors: Jian Zhang;Abdelmounaïm Tounzi;Phillipe Delarue;Francis Piriou;Vlasios Leontidis;Antoine Dazin;Guy Caignaert;Antoine Libaux;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Quantitative Susceptibility Mapping (QSM) Algorithms: Mathematical Rationale and Computational Implementations
Abstract:
Quantitative susceptibility mapping (QSM) solves the magnetic field-to-magnetization (tissue susceptibility) inverse problem under conditions of noisy and incomplete field data acquired using magnetic resonance imaging. Therefore, sophisticated algorithms are necessary to treat the ill-posed nature of the problem and are reviewed here. The forward problem is typically presented as an integral form, where the field is the convolution of the dipole kernel and tissue susceptibility distribution. This integral form can be equivalently written as a partial differential equation (PDE). Algorithmic challenges are to reduce streaking and shadow artifacts characterized by the fundamental solution of the PDE. Bayesian maximum a posteriori estimation can be employed to solve the inverse problem, where morphological and relevant biomedical knowledge (specific to the imaging situation) are used as priors. As the cost functions in Bayesian QSM framework are typically convex, solutions can be robustly computed using a gradient-based optimization algorithm. Moreover, one can not only accelerate Bayesian QSM, but also increase its effectiveness at reducing shadows using prior knowledge based preconditioners. Improving the efficiency of QSM is under active development, and a rigorous analysis of preconditioning needs to be carried out for further investigation.
Autors: Youngwook Kee;Zhe Liu;Liangdong Zhou;Alexey Dimov;Junghun Cho;Ludovic de Rochefort;Jin Keun Seo;Yi Wang;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Nov 2017, volume: 64, issue:11, pages: 2531 - 2545
Publisher: IEEE
 
» Quantum Transport Simulation of Nanowire Resonant Tunneling Diodes Based on a Wigner Function Model With Spatially Dependent Effective Masses
Abstract:
We present a self-consistent and three-dimensional quantum simulation for nanowire resonant tunneling diodes (RTDs) based on the Wigner transport equation with spatially dependent effective masses (SDEM), which is discretized by a third-order upwind difference scheme for high-accuracy calculation. Our calculation shows that the current density/voltage () characteristics of nanowire RTDs with a radius () 5 nm largely deviate from those of the one-dimensional RTDs. As decreases below 5 nm, the peak-to-valley ratio (PVR) of the low- negative differential resistance (NDR) decreases rapidly, and the high- NDR peak shifts sensitively to lower and becomes sharper. In this study, these results are shown to be closely related to the SDEM. According to our analysis, the SDEM along the transport direction contributes to the formation of an ‘effective double barrier’ in the energy subbands that is higher than the double barrier expected by the band offset, and the SDEM along the confinement direction reduces the height of the effective double barrier. The performance of nanowire RTDs with 5 nm was proven to be highly dependent on because of the SDEM along the confinement direction.
Autors: Joon-Ho Lee;Mincheol Shin;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Nov 2017, volume: 16, issue:6, pages: 1028 - 1036
Publisher: IEEE
 
» Quasi-Lumped-Element Filter-Integrated Single-Pole Double-Throw Switch
Abstract:
In this paper, the capacitively coupled LC resonators with loaded p-i-n diodes are used to develop fixed-response filter-integrated single-pole double-throw (SPDT) switch. The filter-integrated on-state channel with reverse-biased p-i-n diodes can be designed and synthesized using the coupled-resonator filter theory, and the off-state channel with forward-biased p-i-n diodes exhibits high suppression. A 1-GHz filter-integrated SPDT switch with ripple bandwidth of 195 MHz is designed to demonstrate the proposed design concept. Measured results show that it has a low on-state insertion loss (IL) of 1.03 dB, a wide passband, high off-state suppression (OSS), high port-to-port isolation, and compact circuit size. Since both the properly misaligned resonant frequencies of LC resonators and weakly coupling between LC resonators also result in high suppression, a frequency-agile filter-integrated switchless SPDT switch without p-i-n diodes can be designed by using the varactor diodes to realize the corresponding capacitors. A frequency-agile filter-integrated switchless SPDT switch with constant 1-dB fractional bandwidth of 19.5% is also designed. Measured results show that its operating frequency can be tuned from 0.612 to 1.088 GHz with corresponding frequency tuning range of 58% and IL varying from 2.8 to 2.3 dB. Good return loss, high OSS, and port-to-port isolation can be also observed.
Autors: Jin Xu;Qi-Hang Cai;Zhi-Yu Chen;Yong-Qian Du;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Nov 2017, volume: 65, issue:11, pages: 4564 - 4571
Publisher: IEEE
 
» Quasi-Static AC FORC Measurements for Soft Magnetic Materials and Their Differential Interpretation
Abstract:
A detailed analysis of the first-order reversal curve (FORC) measurements offers the possibility to separate the different magnetic interactions in multiphase or composite magnetic materials, and then to attain a precise interpretation of the role played by those interactions. In this paper, we present a modified setup based on a classical inductive magnetometer optimized for FORC measurements in soft magnetic materials, together with an improved differential method for the data analysis in order to get an accurate interpretation of the experimental results.
Autors: Montserrat Rivas;Pedro Gorria;Cristina Muñoz-Gómez;José Carlos Martínez-García;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Radiated Electromagnetic Emission for Integrated Circuit Authentication
Abstract:
Counterfeiting of integrated circuit (IC) is a growing concern in the semiconductor industry. Counterfeiting involves economical and safety issues. Both semiconductor companies and embedded system designers are looking for traceability solution in order to get assurance in IC they use. This letter proposes to use electromagnetic (EM) radiated emission from IC to create an unique fingerprint for each IC. We have proposed to use a variability-aware circuit configuration which would exploit EM fingerprint for each IC. Our measurement results on two different field-programmable gate array (FPGA) families over several test boards validate this scheme. As a last step, postprocessing on the obtained EM measurements is done to get a unique FPGA signature which could be used for the purpose of authentication.
Autors: Mosabbah Mushir Ahmed;David Hely;Nicolas Barbot;Romain Siragusa;Etienne Perret;Maxime Bernier;Fredric Garet;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Nov 2017, volume: 27, issue:11, pages: 1028 - 1030
Publisher: IEEE
 
» Radiated EMI Modeling and Performance Analysis of a PWM PMSM Drive System Based on Field-Circuit Coupled FEM
Abstract:
The radiated electromagnetic interference (EMI) behavior may have a negative impact on the machining accuracy of grinding machines. Therefore, this paper focuses on the radiated EMI generated by an ultra-precision pulsewidth modulation permanent-magnet synchronous motor (PMSM) drive system. The excitation for the radiated EMI model, the common-mode (CM) ground current at the output terminal of the converter, is obtained by simulating its conducted EMI model. The reasonable simplified FE models for the converter frame, the shielded power cable, and the motor frame are established. In addition, an equivalent circuit macro model of the CM impedance of the three-phase PMSM windings is obtained by using impedance measurements, the vector fitting method, and the fast residue perturbation method. Finally, the 3-D time harmonic field-circuit coupled finite-element method is employed to evaluate the radiated EMI.
Autors: Youpeng Huangfu;Shuhong Wang;Luca Di Rienzo;Jianguo Zhu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Rail-to-Rail-Input Dual-Radio 64-Channel Closed-Loop Neurostimulator
Abstract:
A 64-channel 0.13- CMOS system on a chip (SoC) for neuroelectrical monitoring and responsive neurostimulation is presented. The -based neural channel records signals with rail-to-rail dc offset at the input without any area-intensive dc-removing passive components, which leads to a compact 0.013-mm2 integration area of recording and stimulation circuits. The channel consumes 630 nW, yields a signal to noise and distortion ratio of 72.2 dB, a 1.13-Vrms integrated input-referred noise over 0.1–500 Hz frequency range, and a noise efficiency factor of 2.86. Analog multipliers are implemented in each channel with minimum additional area cost by reusing the multi-bit current-digital to analog converter that is originally placed for current-mode stimulation. The multipliers are used for compact implementation of bandpass finite impulse response filters, as well as voltage gain scaling. A tri-core low-power DSP conducts phase-synchrony-based neurophysiological event detection and triggers a subset of 64 programmable arbitrary-waveform current-mode stimulators for subsequent neuromodulation. Two ultra-wideband (UWB) wireless transmitters communicate to receivers located at 10 cm to 2 m distance from the implanted SoC with data rates of 10–46 Mb/s, respectively. An inductive link that operates at 1.5 MHz provides power to the SoC and is also used to communicate commands to an on-chip ASK receiver. The chip occupies 6 mm2 while consuming 1.07 and 5.44 mW with delay-based and voltage controlled oscillator-based UWB transmitters, respectively. The SoC is validated in vivo using epilepsy monitoring (seizure detection) and treatment (seizure suppression)- experiments.
Autors: Hossein Kassiri;Muhammad Tariqus Salam;Mohammad Reza Pazhouhandeh;Nima Soltani;Jose Luis Perez Velazquez;Peter Carlen;Roman Genov;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Nov 2017, volume: 52, issue:11, pages: 2793 - 2810
Publisher: IEEE
 
» Rainfall Rate Prediction for Propagation Applications: Model Performance at Regional Level Over Ireland
Abstract:
Three global rainfall rate prediction methods are evaluated in their ability to estimate local precipitation statistics, which are the key to predict the impact of rain on the propagation of electromagnetic waves through the atmosphere. Specifically, the International Telecommunication Union-Radiocommunication Sector (ITU-R) P.837-6, model for rainfall statistics estimation (MORSE), and the ITU-R P.837-7 prediction methods are tested against long-term rainfall data collected in 19 sites in Ireland. The results indicate that the ITU-R P.837-7 prediction method delivers the best performance, and that both the ITU-R P.837-6 prediction method and MORSE exhibit a positive bias, likely due to the overestimation of the yearly rain amount in the maps used as input to such models. The results of the testing activity provide information on the accuracy of rainfall rate prediction methods at regional level, an important factor to consider given the direct link between the magnitude of rain-induced attenuation, and the operational frequency of wireless communication links.
Autors: Lorenzo Luini;Luis Emiliani;Xavier Boulanger;Carlo Riva;Nicolas Jeannin;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 6185 - 6189
Publisher: IEEE
 
» Random-to-Random Nodal Distance Distributions in Finite Wireless Networks
Abstract:
Most performance metrics in wireless networks, such as outage probability, link capacity, etc., are functions of the distances between communicating/interfering nodes. A probabilistic distance-based model is definitely needed in quantifying these metrics, which eventually involves the nodal distance distribution (NDD) in a finite network intrinsically depending on the network coverage and nodal spatial distribution. Recently, the NDD from a reference node to a uniformly distributed node has been extended to the networks in the shape of arbitrary polygons. In contrast, the NDD between two uniformly distributed nodes (Ran2Ran) is still confined to the networks in certain specific shapes, including disks, triangles, rectangles, rhombuses, trapezoids, and regular polygons, which greatly limits its applicable network scenarios. By extending a tool in integral geometry, called Kinematic Measure, and using decomposition and recursion methods, this paper shows a systematic, algorithmic approach to Ran2Ran NDDs, which can handle arbitrarily-shaped networks, including convex, concave, disjoint, and tiered networks. Besides validating our approach through extensive simulations and comparisons with the known results if applicable, we also demonstrate its potentials in handling nonuniform nodal distributions, and in modeling two wireless networks of particular interest in the current literature, where the existing approaches are inapplicable.
Autors: Fei Tong;Jianping Pan;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10070 - 10083
Publisher: IEEE
 
» Rapid Spatial Mapping of Focused Ultrasound Fields Using a Planar Fabry–Pérot Sensor
Abstract:
Measurement of high acoustic pressures is necessary in order to fully characterize clinical high-intensity focused ultrasound (HIFU) fields, and for accurate validation of computational models of ultrasound propagation. However, many existing measurement devices are unable to withstand the extreme pressures generated in these fields, and those that can often exhibit low sensitivity. Here, a planar Fabry–Pérot interferometer with hard dielectric mirrors and spacer was designed, fabricated, and characterized, and its suitability for measurement of nonlinear focused ultrasound fields was investigated. The noise equivalent pressure (NEP) of the scanning system scaled with the adjustable pressure detection range between 49 kPa for pressures up to 8 MPa and 152 kPa for measurements up to 25 MPa, over a 125 MHz measurement bandwidth. Measurements of the frequency response of the sensor showed that it varied by less than 3 dB in the range 1–62 MHz. The effective element size of the sensor was 65 and waveforms were acquired at a rate of 200 Hz. The device was used to measure the acoustic pressure in the field of a 1.1 MHz single-element spherically focused bowl transducer. Measurements of the acoustic field at low pressures compared well with measurements made using a Polyvinylidene difluoride needle hydrophone. At high pressures, the measured peak focal pressures agreed well with the focal pressure modeled using the Khokhlov–Zabolotskaya–Kuznetsov equation. Maximum peak positive pressures of 25 MPa and peak negative pressures of 12 MPa were measured, and planar field scans were acquired in scan times on the order of 1 min. The properties of the sensor and scanning system are well suited to measurement of nonlinear focused ultrasound fields, in both the focal region and the low-pressure periphe- al regions. The fast acquisition speed of the system and its low NEP are advantageous, and with further development of the sensor, it has potential in application to HIFU metrology.
Autors: Eleanor Martin;Edward Z. Zhang;James A. Guggenheim;Paul C. Beard;Bradley E. Treeby;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Nov 2017, volume: 64, issue:11, pages: 1711 - 1722
Publisher: IEEE
 

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