Electrical and Electronics Engineering publications abstract of: 10-2017 sorted by title, page: 9

» Equivalence of Finite Dimensional Input–Output Models of Solute Transport and Diffusion in Geosciences
Abstract:
We show that for a large class of finite dimensional input–output positive systems that represent networks of transport and diffusion of solute in geological media, there exist equivalent multirate mass transfer and multiple interacting continua representations, which are quite popular in geosciences. Moreover, we provide explicit methods to construct these equivalent representations. The proofs show that controllability property is playing a crucial role. These results contribute to our fundamental understanding on the effect of fine-scale geological structures on the transfer and dispersion of solute.
Autors: Alain Rapaport;Alejandro Rojas-Palma;Jean-Raynald de Dreuzy;Hector C. Ramírez;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5470 - 5477
Publisher: IEEE
 
» Error Characterization of Soil Moisture Satellite Products: Retrieving Error Cross-Correlation Through Extended Quadruple Collocation
Abstract:
The triple collocation (TC) technique is being increasingly used to validate soil moisture retrievals derived from different systems, like satellites, hydrological models, or in situ probes. In recent years, several extensions of this method were proposed in order to evaluate the error standard deviations of more than three systems and to soften the TC hypothesis. In this paper, a novel extended quadruple collocation (E-QC) method is proposed, in order to consider the possibility of a cross correlation between product errors, identifying automatically the couple of error cross-correlated systems. The method is applicable even to a larger number of collocated datasets, although it may be unfeasible to collect them in practice. A synthetic experiment showed promising results, concluding that the E-QC is able to individuate (if any) the pair of systems with cross-correlated errors. It correctly compensates for the latter contribution and accurately retrieves error standard deviations of each system, otherwise biased if cross correlation is not taken into account. The E-QC was applied to soil moisture retrievals provided by satellite (SMOS, ASCAT, and SMAP), model (ERA Interim), and in situ probes (ISMN). The E-QC method identified the presence of error cross-correlation between the satellite products. This was also confirmed by analyzing the five datasets all together. E-QC showed fair performances of satellite products, especially of SMAP, although not as good as in case the presence of error correlation is not correctly taken into account.
Autors: Nazzareno Pierdicca;Fabio Fascetti;Luca Pulvirenti;Raffaele Crapolicchio;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Oct 2017, volume: 10, issue:10, pages: 4522 - 4530
Publisher: IEEE
 
» Error-Voltage-Based Open-Switch Fault Diagnosis Strategy for Matrix Converters with Model Predictive Control Method
Abstract:
This paper proposes an error-voltage-based open-switch fault-diagnosis a strategy for a matrix converter (MC). A finite control set model predictive control method is used to operate the MC. The MC system performances under normal operation and under a single open-switch fault operation are analyzed. A fault-diagnosis strategy has also been implemented in two steps. First, the faulty phase is detected and identified based on a comparison of the reference and estimated output line-to-line voltages. Then, the faulty switch is located by considering the switching states of the faulty phase. The proposed fault-diagnosis method is able to locate the faulty switch accurately and quickly without additional voltage sensors. Simulation and experimental results are presented to demonstrate the feasibility and effectiveness of the proposed strategy.
Autors: Hanbing Dan;Tao Peng;Mei Su;Hui Deng;Qi Zhu;Ziyi Zhao;Patrick Wheeler;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4603 - 4612
Publisher: IEEE
 
» Estimating Circuit Aging Due to BTI and HCI Using Ring-Oscillator-Based Sensors
Abstract:
The performance of nanometer-scale circuits is adversely affected by aging induced by bias temperature instability (BTI) and hot carrier injection (HCI). Both BTI and HCI impact transistor electrical parameters at a level that depends on the operating environment and usage of the circuit. This paper presents a novel method, using on-chip sensors based on ring oscillators (ROSCs), to detect the delay shifts in circuits as a result of aging. Our method uses presilicon analysis of the circuit to compute calibration factors that can translate BTI- and HCI-induced delay shifts in the ROSC to those in the circuit of interest. Our simulations show that the delay estimates are within 1% of the true values from presilicon analysis. Further, for post-silicon analysis, a refinement strategy is proposed where sensor measurements can be amalgamated with infrequent online delay measurements on the monitored circuit to partially capture its true workloads. This leads to about 8% lower delay guardbanding overheads compared to the conventional methods as demonstrated using benchmark circuits.
Autors: Deepashree Sengupta;Sachin S. Sapatnekar;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Oct 2017, volume: 36, issue:10, pages: 1688 - 1701
Publisher: IEEE
 
» Estimating Cortical Feature Maps with Dependent Gaussian Processes
Abstract:
A striking example of brain organisation is the stereotyped arrangement of cell preferences in the visual cortex for edges of particular orientations in the visual image. These “orientation preference maps” appear to have remarkably consistent statistical properties across many species. However fine scale analysis of these properties requires the accurate reconstruction of maps from imaging data which is highly noisy. A new approach for solving this reconstruction problem is to use Bayesian Gaussian process methods, which produce more accurate results than classical techniques. However, so far this work has not considered the fact that maps for several other features of visual input coexist with the orientation preference map and that these maps have mutually dependent spatial arrangements. Here we extend the Gaussian process framework to the multiple output case, so that we can consider multiple maps simultaneously. We demonstrate that this improves reconstruction of multiple maps compared to both classical techniques and the single output approach, can encode the empirically observed relationships, and is easily extendible. This provides the first principled approach for studying the spatial relationships between feature maps in visual cortex.
Autors: Nicholas J. Hughes;Geoffrey J. Goodhill;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Oct 2017, volume: 39, issue:10, pages: 1918 - 1928
Publisher: IEEE
 
» Estimating Fractional Vegetation Cover From Landsat-7 ETM+ Reflectance Data Based on a Coupled Radiative Transfer and Crop Growth Model
Abstract:
Fractional vegetation cover (FVC) is an important parameter for earth surface process simulations, climate modeling, and global change studies. Currently, several FVC products have been generated from coarse resolution (~1 km) remote sensing data, and have been widely used. However, coarse resolution FVC products are not appropriate for precise land surface monitoring at regional scales, and finer spatial resolution FVC products are needed. Time-series coarse spatial resolution FVC products at high temporal resolutions contain vegetation growth information. Incorporating such information into the finer spatial resolution FVC estimation may improve the accuracy of FVC estimation. Therefore, a method for estimating finer spatial resolution FVC from coarse resolution FVC products and finer spatial resolution satellite reflectance data is proposed in this paper. This method relies on the coupled PROSAIL radiative transfer model and a statistical crop growth model built from the coarse resolution FVC product. The performance of the proposed method is investigated using the time-series Global LAnd Surface Satellite FVC product and Landsat-7 Enhanced Thematic Mapper Plus reflectance data in a cropland area of the Heihe River Basin. The direct validation of the FVC estimated using the proposed method with the ground measured FVC data (, RMSE =0.0884), compared with the widely used dimidiate pixel model (, RMSE = 0.1575), shows that the proposed method is feasible for estimating finer spatial resolution FVC with satisfactory accuracy, and it has the potential to be applied at a large scale.
Autors: Xiaoxia Wang;Kun Jia;Shunlin Liang;Qiangzi Li;Xiangqin Wei;Yunjun Yao;Xiaotong Zhang;Yixuan Tu;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5539 - 5546
Publisher: IEEE
 
» Estimation of Significant Wave Height From X-Band Marine Radar Images Based on Ensemble Empirical Mode Decomposition
Abstract:
In this letter, an ensemble empirical mode decomposition (EEMD)-based method is proposed to estimate significant wave height (SWH) from the X-band marine radar sea surface images. First, the data sequence in each radial direction of a radar subimage is decomposed by the EEMD into several intrinsic mode functions (IMFs). A normalization scheme is then applied to the IMFs to obtain their amplitude modulation components. Finally, by adopting a linear model, the SWH is estimated from the sum of the amplitudes from the second to the fifth modes. The method is tested using radar and buoy data collected in a sea trial off the east coast of Canada. The root-mean-square differences with respect to the buoy reference for the SWH estimations using the traditional signal-to-noise-based method, a recent shadowing-based method, and the proposed technique are 0.78, 0.48, and 0.36 m, respectively. The result indicates that the proposed technique produces improvement in the SWH measurements.
Autors: Xinlong Liu;Weimin Huang;Eric W. Gill;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1740 - 1744
Publisher: IEEE
 
» Evaluating Scattering Contributions to C-Band Radar Backscatter From Snow-Covered First-Year Sea Ice at the Winter–Spring Transition Through Measurement and Modeling
Abstract:
In this paper, we present model and measurement results for time-series angular dependencies of C-band HH and VV normalized radar cross-sections (NRCS) over first-year snow-covered sea ice during a winter–spring transition period. Experimental scatterometer and physical data were collected near Cambridge Bay, Nunavut, Canada, between May 20 and May 28, 2014, covering a severe storm event on May 25. We use the small perturbation scattering theory to model small-scale surface scattering, the Mie scattering theory to estimate the level of volume scattering in snow, and the Kirchhoff physical optics model to compute the large-scale surface scattering component. We observed good agreement between the model and experimental HH and VV NRCS. Before the storm, between model and experimental NRCS was 0.88 and 0.82 for VV and HH, respectively. After the storm, was 0.81 and 0.78 for VV and HH, respectively. Our model results suggest an overall increase in surface roughness after the storm event, supported by LiDAR measurements of the snow surface topography. Before the storm, the large-scale and small-scale surface scattering from the air-snow interface as well as volume scattering components dominated. After the storm, the large- and small-scale scattering contributions increased, while the volume scattering component considerably dropped. We attribute these effects to the increase in surface roughness and snow moisture content during the poststorm period. Our results could aid in interpretation of time-series synthetic aperture radar images with respect to physical properties of snow and ice during the winter–spring transition period.
Autors: Alexander S. Komarov;Jack C. Landy;Sergey A. Komarov;David G. Barber;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5702 - 5718
Publisher: IEEE
 
» Evaluating the Performance of Digital Modular Protection for Grid-Connected Permanent-Magnet-Generator-Based Wind Energy Conversion Systems With Battery Storage Systems
Abstract:
This paper develops and tests a new method for managing the responses of multiple digital relays employed in interconnected permanent-magnet generator (PMG)-based wind energy conversion systems (WECSs) with battery storage. The developed method utilizes digital relays (modules), each of which provides protection for a specific location of the PMG-based WECS and battery storage. The outputs of the developed digital protection scheme are trip signals to operate circuit breakers in PMG-based WECS, battery storage, and point-of-common-coupling. The modular digital protection is implemented for experimental testing on a 5-kW PMG-based WECS that has a 2.3-kW battery storage. Test results show that the developed protection can offer fast, accurate, and reliable responses to faults occurring in different parts of the tested WECS and battery storage. In addition, test results show that the modular digital protection has minor sensitivity to the location of faults, charge/discharge cycles of the battery storage, and/or levels of power delivery to the host grid.
Autors: S. A. Saleh;Ryan Meng;Ryan McSheffery;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4186 - 4200
Publisher: IEEE
 
» Evaluation of Fast Neutron Fluence for Reactor Pressure Vessel Surveillance of Chashma Nuclear Power Plants Units 1 and 2
Abstract:
The energy-dependent neutron flux incident on surveillance capsule assemblies (SCAs) installed at the outer surface of the core barrel in two pressurized water reactors—Chashma Nuclear Power Plants Units 1 and 2 was evaluated. This safety study was made for the reactor pressure vessel surveillance program to determine the fast-neutron-induced radiation embrittlement of vessel materials in sections facing the core side and the upper weld positions. A total of 68 radiometric sensors were irradiated in each SCA of these two reactors, and dosimetry data were measured from radiometric sensors. Fast neutron flux ( MeV) was best estimated using the least-squares method by employing LSL-M2 package. Measured results were compared with the fast neutron flux calculated using MCNP5 at the base and weld metal sections of SCA. The results agreed within ±20% of each other in both reactors, which satisfy the regulatory acceptance criteria. Therefore, these results can be used in life assessment of reactors.
Autors: Asim Saeed;Noureen Akhtar;Tariq Rashid;Saleem A. Ansari;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Oct 2017, volume: 64, issue:10, pages: 2661 - 2668
Publisher: IEEE
 
» Evaluation of Negative Capacitance Ferroelectric MOSFET for Analog Circuit Applications
Abstract:
Negative capacitance ferroelectric (FE) field-effect transistor (FeFET) is promising to address the issue of the increasing power density in digital circuit by realizing sub-60 mV/decade subthreshold swing. This inspires us to evaluate its applications in analog circuit. In this paper, the evaluation is performed based on the equivalent circuit model and through device- and circuit-level benchmarking against MOSFET counterpart. It is found that the selection of FE thickness is important to balance current amplification and saturated output characteristics. As compared with MOSFET, FeFET exhibits a larger current, transconductance, and current-to-transconductance generation efficiency. Its output resistance is smaller in the linear region and larger in the saturation region. It also has less variation in threshold voltage with temperature. When implementing FeFETs into various analog circuit applications, we find that a node capacitor could be discharged within shorter time to increase circuit speed; A better analog switch consisting of complementary FeFETs exhibits a lower and more linear on-resistance; Differential amplifier provides larger voltage amplification to small input signal; Current mirror transfers a more precise output current to the reference one.
Autors: Yang Li;Yuye Kang;Xiao Gong;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4317 - 4321
Publisher: IEEE
 
» Evaluation of Segmentation Quality via Adaptive Composition of Reference Segmentations
Abstract:
Evaluating image segmentation quality is a critical step for generating desirable segmented output and comparing performance of algorithms, among others. However, automatic evaluation of segmented results is inherently challenging since image segmentation is an ill-posed problem. This paper presents a framework to evaluate segmentation quality using multiple labeled segmentations which are considered as references. For a segmentation to be evaluated, we adaptively compose a reference segmentation using multiple labeled segmentations, which locally matches the input segments while preserving structural consistency. The quality of a given segmentation is then measured by its distance to the composed reference. A new dataset of 200 images, where each one has 6 to 15 labeled segmentations, is developed for performance evaluation of image segmentation. Furthermore, to quantitatively compare the proposed segmentation evaluation algorithm with the state-of-the-art methods, a benchmark segmentation evaluation dataset is proposed. Extensive experiments are carried out to validate the proposed segmentation evaluation framework.
Autors: Bo Peng;Lei Zhang;Xuanqin Mou;Ming-Hsuan Yang;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Oct 2017, volume: 39, issue:10, pages: 1929 - 1941
Publisher: IEEE
 
» Evaluation of SiC Schottky Diodes Using Pressure Contacts
Abstract:
The thermomechanical reliability of SiC power devices and modules is increasingly becoming of interest especially for high-power applications, where power cycling performance is critical. Press-pack assemblies are a trusted and reliable packaging solution that has traditionally been used for high-power thyristor-based applications in FACTS/HVDC, although press-pack IGBTs have become commercially available more recently. These press-pack IGBTs require antiparallel PiN diodes for enabling reverse conduction capability. In these high-power applications, paralleling chips for high current conduction capability is a requirement, hence, electrothermal stability during current sharing is critical. SiC Schottky diodes not only exhibit the advantages of wide bandgap technology compared to silicon PiN diodes, but they have significantly lower zero temperature coefficient (ZTC), meaning they are more electrothermally stable. The lower ZTC is due to the unipolar nature of SiC Schottky diodes as opposed to the bipolar nature of PiN diodes. This paper investigates the implementation and reliability of SiC Schottky diodes in press-pack assemblies. The impact of pressure loss on the electrothermal stability of parallel devices is investigated.
Autors: Jose Ortiz Gonzalez;Olayiwola Alatise;Attahir Murtala Aliyu;Pushparajah Rajaguru;Alberto Castellazzi;Li Ran;Philip A. Mawby;Chris Bailey;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8213 - 8223
Publisher: IEEE
 
» Event-Based Energy Disaggregation Algorithm for Activity Monitoring From a Single-Point Sensor
Abstract:
The massive deployment of smart meters and other customized meters has motivated the development of nonintrusive load monitoring (NILM) systems. This is the process of disaggregating the total energy consumption in a building into individual electrical loads using a single-point sensor. Most literature is oriented to energy saving. Nevertheless, activity of daily livings monitoring through NILM is recently receiving much interest. This proposal presents an event-based NILM algorithm of high performance for activity monitoring applications. This is divided into two stages: 1) an event detector and 2) an event classification algorithm. The first one does not need to be trained and shows a detection rate up to 94%. The event classification algorithm uses a novel load signature based on trajectories of active, reactive, and distortion power (PQD) to obtain general models of appliance classes using principal component analysis. The F1 score and the F0.5 score (the last one is more relevant to activity monitoring) draw values of 90.6% and 98.5, respectively.
Autors: José Alcalá;Jesús Ureña;Álvaro Hernández;David Gualda;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Oct 2017, volume: 66, issue:10, pages: 2615 - 2626
Publisher: IEEE
 
» Event-Driven Nonlinear Discounted Optimal Regulation Involving a Power System Application
Abstract:
By employing neural network approximation architecture, the nonlinear discounted optimal regulation is handled under event-driven adaptive critic framework. The main idea lies in adopting an improved learning algorithm, so that the event-driven discounted optimal control law can be derived via training a neural network. The stability guarantee and simulation illustration are also included. It is highlighted that the initial stabilizing control policy is not required during the implementation process with the combined learning rule. Moreover, the closed-loop system is formulated as an impulsive model. Then, the related stability issue is addressed by using the Lyapunov approach. The simulation studies, including an application to a power system, are also conducted to verify the effectiveness of the present design method.
Autors: Ding Wang;Haibo He;Xiangnan Zhong;Derong Liu;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8177 - 8186
Publisher: IEEE
 
» Event-Triggered Active Disturbance Rejection Control of DC Torque Motors
Abstract:
Physical servo systems are affected by disturbances, uncertainties, and resource restrictions. In this paper, an event-triggered active disturbance rejection control approach is proposed to achieve position tracking of dc torque motors. An event-based sampler together with an extended state observer is introduced, which allows the joint observation of the system state, and the total disturbance induced by model uncertainty and intermittent sampling. Based on the observation results, closed-loop control is achieved with guaranteed stable tracking performance. To quantify the effect of event-based sampling, a quantitative relationship between the asymptotic upper bound of tracking error and the parameters in the event-based sampler is developed. The control strategy is applied to a dc torque motor system, and comparative experimental results indicate that for different reference signals, the proposed event-based control strategy can achieve satisfactory tracking performance with reduced sampling cost.
Autors: Dawei Shi;Jian Xue;Lixun Zhao;Junzheng Wang;Yuan Huang;
Appeared in: IEEE/ASME Transactions on Mechatronics
Publication date: Oct 2017, volume: 22, issue:5, pages: 2277 - 2287
Publisher: IEEE
 
» Event-Triggered Control of Multiagent Systems for Fixed and Time-Varying Network Topologies
Abstract:
A decentralized controller that uses event-triggered communication scheduling is developed for the leader-follower consensus problem under fixed and switching communication topologies. To eliminate continuous interagent communication, state estimates of neighboring agents are designed for control feedback and are updated via communication to reset growing estimate errors. The communication times are based on an event-triggered approach and are adapted based on the trade-off between the control system performance and the desire to minimize the amount of communication. An important aspect of the developed event trigger strategy is that communication is not required to determine when a state update is needed. Since the control strategy produces switched dynamics, analysis is provided to show that Zeno behavior is avoided by developing a positive constant lower bound on the minimum inter-event interval. A Lyapunov-based convergence analysis is also provided to indicate bounded convergence of the developed control methodology.
Autors: Teng-Hu Cheng;Zhen Kan;Justin R. Klotz;John M. Shea;Warren E. Dixon;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5365 - 5371
Publisher: IEEE
 
» Event-Triggered Suboptimal Tracking Controller Design for a Class of Nonlinear Discrete-Time Systems
Abstract:
In this paper, using the state-dependent Riccati equation approach, an event-triggered technique is proposed to solve the tracking problem for a broad class of nonlinear discrete-time networked control systems. It is shown that the proposed tracking controller leads to an asymptotically stable system, while the information exchange between the controller and the actuator can be directly affected with predictable results by changing a parameter of the controller called the triggering factor. The proposed method is experimentally validated on a laboratory three-tank system. The obtained results demonstrate the effectiveness of the proposed event-triggered technique for solving the tracking problem of a nonlinear system in a networked control framework.
Autors: Yazdan Batmani;Mohammadreza Davoodi;Nader Meskin;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8079 - 8087
Publisher: IEEE
 
» Ex-Post Max-Min Fairness of Generalized AGV Mechanisms
Abstract:
We generalize the standard Arrow-d'Aspremont-Gerard-Varet (AGV) mechanism to balance the net payoffs received by all agents, while maintaining Bayesian incentive compatibility, ex-post efficiency, and ex-post budget balance of the standard AGV mechanism. In a private-value setting with independent agents' types and the principal's cost, we formulate a convex optimization problem to find the mechanism (that achieves ex-post max-min fairness) over a set of parameterized generalized AGV mechanisms, through maximizing the expected value of the minimum ex-post net payoff. We reformulate the convex program as a linear program that can be effectively solved when the number of agents is small. When the number of agents is large, we propose to solve the formulated convex program through the incremental subgradient method. Numerical results on two action models show that the proposed mechanism significantly outperforms the standard AGV mechanism in terms of the expected minimum ex-post payoff.
Autors: Tao Wang;Yunjian Xu;Selin Damla Ahipasaoglu;Costas Courcoubetis;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5275 - 5281
Publisher: IEEE
 
» Example-Based Subspace Stress Analysis for Interactive Shape Design
Abstract:
Stress analysis is a crucial tool for designing structurally sound shapes. However, the expensive computational cost has hampered its use in interactive shape editing tasks. We augment the existing example-based shape editing tools, and propose a fast subspace stress analysis method to enable stress-aware shape editing. In particular, we construct a reduced stress basis from a small set of shape exemplars and possible external forces. This stress basis is automatically adapted to the current user edited shape on the fly, and thereby offers reliable stress estimation. We then introduce a new finite element discretization scheme to use the reduced basis for fast stress analysis. Our method runs up to two orders of magnitude faster than the full-space finite element analysis, with average estimation errors less than 2 percent and maximum errors less than 6 percent. Furthermore, we build an interactive stress-aware shape editing tool to demonstrate its performance in practice.
Autors: Xiang Chen;Changxi Zheng;Kun Zhou;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Oct 2017, volume: 23, issue:10, pages: 2314 - 2327
Publisher: IEEE
 
» Exchangeability Characterizes Optimality of Sequential Normalized Maximum Likelihood and Bayesian Prediction
Abstract:
We study online learning under logarithmic loss with regular parametric models. In this setting, each strategy corresponds to a joint distribution on sequences. The minimax optimal strategy is the normalized maximum likelihood (NML) strategy. We show that the sequential NML (SNML) strategy predicts minimax optimally (i.e., as NML) if and only if the joint distribution on sequences defined by SNML is exchangeable. This property also characterizes the optimality of a Bayesian prediction strategy. In that case, the optimal prior distribution is Jeffreys prior for a broad class of parametric models for which the maximum likelihood estimator is asymptotically normal. The optimal prediction strategy, NML, depends on the number of rounds of the game, in general. However, when a Bayesian strategy is optimal, NML becomes independent of . Our proof uses this to exploit the asymptotics of NML. The asymptotic normality of the maximum likelihood estimator is responsible for the necessity of Jeffreys prior.
Autors: Fares Hedayati;Peter L. Bartlett;
Appeared in: IEEE Transactions on Information Theory
Publication date: Oct 2017, volume: 63, issue:10, pages: 6767 - 6773
Publisher: IEEE
 
» Expanding Acquisition and Clutter Filter Dimensions for Improved Perfusion Sensitivity
Abstract:
A method is explored for increasing the sensitivity of power-Doppler imaging without contrast enhancement. We acquire 1–10 s of echo signals and arrange it into a 3-D spatiotemporal data array. An eigenfilter developed to preserve all three dimensions of the array yields power estimates for blood flow and perfusion that are well separated from tissue clutter. This method is applied at high frequency (24-MHz pulses) to a murine model of an ischemic hindlimb. We demonstrate enhancements to tissue perfusion maps in normal and ischemic tissues. The method can be applied to data from any ultrasonic instrument that provides beamformed RF echo data.
Autors: MinWoo Kim;Craig K. Abbey;Jamila Hedhli;Lawrence W. Dobrucki;Michael F. Insana;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Oct 2017, volume: 64, issue:10, pages: 1429 - 1438
Publisher: IEEE
 
» Expeditus: Congestion-Aware Load Balancing in Clos Data Center Networks
Abstract:
Data center networks often use multi-rooted Clos topologies to provide a large number of equal cost paths between two hosts. Thus, load balancing traffic among the paths is important for high performance and low latency. However, it is well known that ECMP—the de facto load balancing scheme—performs poorly in data center networks. The main culprit of ECMP’s problems is its congestion agnostic nature, which fundamentally limits its ability to deal with network dynamics. We propose Expeditus, a novel distributed congestion-aware load balancing protocol for general 3-tier Clos networks. The complex 3-tier Clos topologies present significant scalability challenges that make a simple per-path feedback approach infeasible. Expeditus addresses the challenges by using simple local information collection, where a switch only monitors its egress and ingress link loads. It further employs a novel two-stage path selection mechanism to aggregate relevant information across switches and make path selection decisions. Testbed evaluation on Emulab and large-scale ns-3 simulations demonstrate that, Expeditus outperforms ECMP by up to 45% in tail flow completion times (FCT) for mice flows, and by up to 38% in mean FCT for elephant flows in 3-tier Clos networks.
Autors: Peng Wang;Hong Xu;Zhixiong Niu;Dongsu Han;Yongqiang Xiong;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Oct 2017, volume: 25, issue:5, pages: 3175 - 3188
Publisher: IEEE
 
» Experimental Analysis of Small Drone Polarimetry Based on Micro-Doppler Signature
Abstract:
We present a polarimetric analysis of small drones from different aspect angles. Polarimetric analysis can provide more information of a target, since the returned radar signal is affected by different wave polarization. The analysis is performed with micro-Doppler signature (MDS) to investigate micromotions of the drone detected by the radar. We measured operating small drones in an anechoic chamber from two aspect angles, 0° and 90°. An outdoor experiment was carried out with metal clutters for verification in real environment. The indoor analysis result shows that copolarized antenna receives signals better than cross polarized when the aspect angle is 0°, and vice versa. We also verified that cross-polarized antenna receives MDS from the drone better than copolarized antenna, from outdoors when an aspect angle is almost 90°. By utilizing the polarimetric characteristic of the drone at this frequency band, it is preferable to use a polarimetric radar for drone detection.
Autors: Byung Kwan Kim;Hyun-Seong Kang;Seong-Ook Park;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1670 - 1674
Publisher: IEEE
 
» Experimental Demonstration of the Distributed Feedback Semiconductor Laser With S-Bent Waveguide and Sampled Grating
Abstract:
A distributed feedback (DFB) semiconductor laser based on s-bent waveguide and sampled grating is theoretically studied and experimentally demonstrated. The proposed laser operates with a high side mode suppression ratio (SMSR) when the bias current is changed from 50 to 130 mA. When the bias current is fixed at 130 mA, the SMSR is larger than 55 dB, which is benefit from the suppressed spatial hole burning, while the SMSR of the equivalent phase shifted DFB laser decreases to 39 dB. The wavelength spacing error between two proposed DFB lasers is measured to be 0.089 nm compared with the designed value. When temperature is increased from 20 °C to 42 °C, the presented DFB laser achieves stable single longitudinal mode (SLM) operation with SMSR >51 dB and the wavelength varies from 1562.24 to 1564.6 nm with a slope of 0.11 nm/°C. The s-bent waveguide and sampled grating can be fabricated simply by the common holography exposure and photolithograph technique resulting in a low cost. Besides, the wavelength accuracy and SLM yield can be improved significantly, which is very beneficial for the multiwavelength DFB laser array.
Autors: Yunshan Zhang;Yuechun Shi;Lianyan Li;Zhengpeng Zou;Jun Lu;Yinchao Du;Wenxuan Wang;Yating Zhou;Xin Chen;Jilin Zheng;Xiangfei Chen;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 11
Publisher: IEEE
 
» Experimental Investigation of a New Tribo-Aeroelectrostatic Separation Process for Micronized Plastics From WEEE
Abstract:
Tribo-electrostatic separation of mm-size granular insulating materials is a process widely used in the plastics recycling industry. However, the separation of micronized plastics is still inefficient because of their tendency to aggregate. The paper is aimed at validating the feasibility of a new tribo-aero-electrostatic separation process for micronized mixed plastics originating from waste electric and electronic equipment. The separation process is based on a fluidized bed tribocharging system equipped with rotating roll electrode connected to a dc high-voltage supply. The micronized insulating materials to be separated (white and grey polyvinyl chloride particles of average size 20 µm) were tribocharged using the fluidization air provided by a variable-speed blower. The charged particles were pinned to the rotating electrode of opposite polarity. This process enabled the sorting of one product while the other materials were left in the fluidized bed. The new electrode configuration has the merit to significantly reduce the particle aggregation problem that affects the operation of other fluidized-bed-type tribocharging devices. The separation outcome, in terms of recovery and purity, depended on several factors, and was found to be optimal for a voltage of 35 kV and a rotation speed of roll electrode of 60 r/min. This new process was also tested for ternary mixtures of granular plastics and the obtained results demonstrate its effectiveness for recovering a targeted product, according to the voltage polarity, leaving the other products in the fluidized bed.
Autors: Mohamed El-Mouloud Zelmat;Amar Tilmatine;Seddik Touhami;Abdelber Bendaoud;Karim Medles;Rabah Ouiddir;Lucian Dascalescu;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4950 - 4956
Publisher: IEEE
 
» Experimental Investigation on Improved Predistortion Circuit for Directly Modulated Radio Over Fiber System
Abstract:
An extension of the conventional dual Schottky diode-based predistortion circuit (PDC) is proposed to linearize directly modulated radio over fiber (RoF) system. The main advantages of the proposed PDC are simple configuration, excellent distortion suppression, and broad bandwidth from dc to 6 GHz. By using the proposed cascaded Schottky diodes-based PDC, the condition of third-order intermodulation nonlinearities suppression can be more easily satisfied and the optimal linearization effect can be achieved due to the fact that it has more circuit adjustment parameters. The experimental results show that by using the proposed PDC, the spurious-free dynamic range (SFDR) @2 GHz of the optical transceiver which is designed by ourselves can be improved from 93.8 dB·Hz2/3 to 112.1 dB·Hz4/5 in a 1-Hz bandwidth, corresponding to 7.21% error vector magnitude performance improvement for 20 MHz 64QAM-OFDM @2 GHz signal transmission over 10 km standard single mode fiber. The linearity improvement by using the proposed PDC has also been verified in a commercial optical transceiver based RoF system, and the achieved SFDR @ 2 GHz can be increased from 102.8 dB·Hz2/3 to 121.6 dB·Hz4/5 in a 1-Hz bandwidth.
Autors: Shichao Chen;Lei Deng;Yao Ye;Xiaoman Chen;Mengfan Cheng;Ming Tang;Songnian Fu;Fengguang Luo;Deming Liu;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 9
Publisher: IEEE
 
» Experimental Study of Multicast and Unicast Video Traffic in WAN Links
Abstract:
In recent years there has been an exponential increase in the growth in multimedia applications, and in particular in video applications. Understanding the behavior of the video traffic and the requirements for the network helps network administrators to improve the traffic. In this work, a quantitative analysis is performed by experimentation, in order to evaluate the behavior and impact of video traffic on WAN networks. We propose a WAN test bed with fourth subescenarios that allows to inject unicast or multicast video traffic, compressed with several codecs. The generic topology used includes a computer running as a streaming server and up to 20 desktop computers (PCs) as clients connected at the ends of a network as if outside a WAN. This network WAN is formed by routers and switchs with different types of links interconnecting the same. For the operation between routers was configured the OSPF routing protocol v2. For the same routers are configured the routing multicast protocol PIM in dense mode. From capturing video traffic, we identified several interesting performance and Qo metrics, such as unicast and multicast throughput, delay, jitter, and Pareto distribution. We include detailed contributions on the impact produced by several factors, such as the codec used for the compression, and the use of unicast and multicast traffic when there are restrictions on the bandwidth, as in a corporate real WAN link of some few Mbps. The work oriented on the configurations to be taken into account for an adequate management of similar networks and an efficient use of the resources available, without compromising the performance and the expected QoS. Besides facilitates the comparison of the results with those obtained from analytical studies and modelling for different contexts.
Autors: Santiago Cristobal Perez;Higinio Alberto Facchini;Luis Marrone;Fabian Ariel Hidalgo;
Appeared in: IEEE Latin America Transactions
Publication date: Oct 2017, volume: 15, issue:10, pages: 1847 - 1855
Publisher: IEEE
 
» Experimental Study on Microsecond Pulse Breakdown Characteristics of Propylene Carbonate Modified by Al Nanoparticles
Abstract:
Liquid dielectrics are very important and useful in pulsed power systems, due to their unique characteristics of large energy storage densities, ease of circulation, and low cost. They are applicable to power systems which have complex geometries. Propylene carbonate (PC), as a kind of polar liquids, shows bright prospects in compact pulsed power sources because of its great permittivity, high electrical breakdown stress, and broad environmental operating ability. In this paper, a dielectric breakdown experiments were conducted with a microsecond pulsed power source and a test cell with spherical electrodes. The breakdown properties of PC and PC-based nanofluids (NFs) were investigated by changing the increasing rate of the charging voltage. Besides, the influence of nanoparticles on the dielectric breakdown characteristics of PC was analyzed. Results show that with a slow increasing rate of the charging voltage, the introduction of nanoparticles greatly improved the breakdown stability of PC; while with a fast increasing rate of the charging voltage, NFs exhibited much larger mean breakdown voltage. We also demonstrated that the improvement effect of NFs’ dielectric performance could be explained by the energy band theory very well.
Autors: Binbin Xu;Zicheng Zhang;Yanpan Hou;Hongwei Liu;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Oct 2017, volume: 45, issue:10, pages: 2691 - 2695
Publisher: IEEE
 
» Experimental Study on Robust Nonlinear Forced Vibration Control for an L-Shaped Arm with Reduced Control Inputs
Abstract:
This paper presents an operator-based robust nonlinear control approach for an L-shaped arm vibration experimental system. The arm is driven by a linear pulse motor to move along a frame and controlled by a piezoelectric actuator in parallel. The aim of this paper is to allow the motor to move fast and reduce the arm vibration by controlling the motion of the motor and the piezoelectric actuator simultaneously. In detail, first, the vibration dynamics of the L-shaped arm is modeled based on the Euler–Bernoulli beam theory. The hysteresis of the piezoelectric actuator is modeled using a Prandtl–Ishlinskii hysteresis model. Second, by using operator-based robust right coprime factorization approach, the proposed control for the system is designed where the linear motor is optimally controlled to reduce the time consumption and the vibration at the vertical part of the arm. Meanwhile, with the hysteresis compensation, the piezoelectric actuator is used to further reduce the vibration at the horizontal part of the arm. Finally, the results of the experiment are demonstrated to verify the effectiveness of the proposed control scheme.
Autors: Yanfeng Wu;Mingcong Deng;
Appeared in: IEEE/ASME Transactions on Mechatronics
Publication date: Oct 2017, volume: 22, issue:5, pages: 2186 - 2195
Publisher: IEEE
 
» Experimental Validation of 3-D Magnet Eddy Current Loss Prediction in Surface-Mounted Permanent Magnet Machines
Abstract:
This paper presents the experimental validation of three-dimensional (3-D) Fourier method employed for predicting magnet eddy current loss in surface-mounted permanent magnet (SPM) machines. The magnet loss is measured for a 12-slot 14-pole SPM machine from experimental tests when the machine is operated with inverter under locked rotor conditions by repeating tests with two rotors, one with magnets and one without. The eddy current loss associated with each significant harmonic in the captured armature currents is predicted separately employing the developed method and the total magnet loss is evaluated by applying the principle of superposition. The magnet loss at real operating conditions of the machine is predicted from the method using the phase current captured when the SPM is operating at its maximum speed conditions. The result is used as an example to devise an effective means of further reduction in the total magnet loss.
Autors: Sreeju Sreedharan Nair;Jiabin Wang;Tianfu Sun;Liang Chen;Robert Chin;Minos Beniakar;Dmitry Svechkarenko;Iakovos Manolas;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4380 - 4388
Publisher: IEEE
 
» Experimental Validation of a Wideband Metasurface for Wide-Angle Scanning Leaky-Wave Antennas
Abstract:
Beam scanning arrays typically suffer from scan loss; an increasing degradation in gain as the beam is scanned from broadside toward the horizon in any given scan plane. Here, a metasurface is presented that reduces the effects of scan loss for a leaky-wave antenna (LWA). The metasurface is simple, being composed of an ultrathin sheet of subwavelength split-ring resonators. The leaky-wave structure is balanced, scanning from the forward region, through broadside, and into the backward region, and designed to scan in the magnetic plane. The metasurface is effectively invisible at broadside, where balanced LWAs are most sensitive to external loading. It is shown that the introduction of the metasurface results in increased directivity, and hence, gain, as the beam is scanned off broadside, having an increasing effect as the beam is scanned to the horizon. Simulations show that the metasurface improves the effective aperture distribution at higher scan angles, resulting in a more directive main beam, while having a negligible impact on cross-polarization gain. Experimental validation results show that the scan range of the antenna is increased from to , when loaded with the metasurface, demonstrating a flattened gain profile over a 135° range centered about broadside. Moreover, this scan range occurs over a frequency band spanning from 9 to 15.5 GHz, demonstrating a relative bandwidth of 53% for the metasurface.
Autors: Trevor R. Cameron;George V. Eleftheriades;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5245 - 5256
Publisher: IEEE
 
» Experimental Validation of Leak and Water-Ingression Detection in Low-Pressure Gas Pipeline Using Pressure and Flow Measurements
Abstract:
In underground low-pressure gas distribution pipelines, ground water enters the pipeline through cracks. This is known as the water ingress problem, and it occurs predominantly in the monsoon season, when the water table is high. This issue is currently detected based on complaints from the users. In order to arrive at an efficient and reliable processing technique, experimental results of pressure and flow on an existing low-pressure gas pipeline are reported in this paper. Several experiments for leak location, severity of the leak, water ingression with various volumes of water followed by removal of water are conducted. Healthy network loading data collected over a 24 h period is used to verify the robustness of the derived parameters for water ingression detection. The present technique can detect leaks easily with a leak valve opening of 30o. Robust detection of water ingression with more than 10% of pipe volume is possible.
Autors: Sugunakar Reddy Ravula;Srivathsan Chakaravarthi Narasimman;Libo Wang;Abhisek Ukil;
Appeared in: IEEE Sensors Journal
Publication date: Oct 2017, volume: 17, issue:20, pages: 6734 - 6742
Publisher: IEEE
 
» Explicit Constructions of Optimal-Access MDS Codes With Nearly Optimal Sub-Packetization
Abstract:
An maximum distance separable (MDS) array code of length , dimension , and sub-packetization is formed of matrices over a finite field , with every column of the matrix stored on a separate node in the distributed storage system and viewed as a coordinate of the codeword. Repair of a failed node (recovery of one erased column) can be performed by accessing a set of surviving (helper) nodes. The code is said to have the optimal access property if the amount of data accessed at each of the helper nodes meets a lower bound on this quantity. For optimal-access MDS codes with , the sub-packetization satisfies the bound . In our previous work (IEEE Trans. Inf. Theory, vol. 63, no. 4, 2017), for any and , we presented an explicit construction of optimal-access MDS codes with sub-packetization . In this paper, we take up the question of reducing the sub-packetization value , which differs from the optimal value by at most a factor of . These codes can be constructed over any finite field as long as , and afford low-complexity encoding and decoding procedures. We also define a version of the repair problem that bridges the context of regenerating codes and codes with locality constraints (LRC codes), which we call group repair with optimal access. In this variation, we assume that the set of nodes is partitioned into repair groups of size , and require that the amount of accessed data for repair is the smallest possible whenever the helper nodes include all the other nodes from the same group as the failed node. For this problem, we construct a family of codes with the group optimal access property. These codes can be constructed over any field of size , and also afford low-complexity encoding and decoding procedures.
Autors: Min Ye;Alexander Barg;
Appeared in: IEEE Transactions on Information Theory
Publication date: Oct 2017, volume: 63, issue:10, pages: 6307 - 6317
Publisher: IEEE
 
» Exploiting Data Reliability and Fuzzy Clustering for Journal Ranking
Abstract:
Journal impact indicators are widely accepted as possible measurements of academic journal quality. However, much debate has recently surrounded their use, and alternative journal impact evaluation techniques are desirable. Aggregation of multiple indicators offers a promising method to produce a more robust ranking result, avoiding the possible bias caused by the use of a single impact indicator. In this paper, fuzzy aggregation and fuzzy clustering, especially the ordered weighted averaging (OWA) operators are exploited to aggregate the quality scores of academic journals that are obtained from different impact indicators. Also, a novel method for linguistic term-based fuzzy cluster grouping is proposed to rank academic journals. The paper allows for the construction of distinctive fuzzy clusters of academic journals on the basis of their performance with respect to different journal impact indicators, which may be subsequently combined via the use of the OWA operators. Journals are ranked in relation to their memberships in the resulting combined fuzzy clusters. In particular, the nearest-neighbor guided aggregation operators are adopted to characterize the reliability of the indicators, and the fuzzy clustering mechanism is utilized to enhance the interpretability of the underlying ranking procedure. The ranking results of academic journals from six subjects are systematically compared with the outlet ranking used by the Excellence in Research for Australia, demonstrating the significant potential of the proposed approach.
Autors: Pan Su;Changjing Shang;Tianhua Chen;Qiang Shen;
Appeared in: IEEE Transactions on Fuzzy Systems
Publication date: Oct 2017, volume: 25, issue:5, pages: 1306 - 1319
Publisher: IEEE
 
» Exploiting Multiple-Antenna Techniques for Non-Orthogonal Multiple Access
Abstract:
This paper aims to provide a comprehensive solution for the design, analysis, and optimization of a multiple-antenna non-orthogonal multiple access (NOMA) system for multiuser downlink communication with both time duplex division and frequency duplex division modes. First, we design a new framework for multiple-antenna NOMA, including user clustering, channel state information (CSI) acquisition, superposition coding, transmit beamforming, and successive interference cancellation. Then, we analyze the performance of the considered system, and derive exact closed-form expressions for average transmission rates in terms of transmit power, CSI accuracy, transmission mode, and channel conditions. For further enhancing the system performance, we optimize three key parameters, i.e., transmit power, feedback bits, and transmission mode. Especially, we propose a low-complexity joint optimization scheme, so as to fully exploit the potential of multiple-antenna techniques in NOMA. Moreover, through asymptotic analysis, we reveal the impact of system parameters on average transmission rates, and hence present some guidelines on the design of multiple-antenna NOMA. Finally, simulation results validate our theoretical analysis, and show that a substantial performance gain can be obtained over traditional orthogonal multiple access technology under practical conditions.
Autors: Xiaoming Chen;Zhaoyang Zhang;Caijun Zhong;Derrick Wing Kwan Ng;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Oct 2017, volume: 35, issue:10, pages: 2207 - 2220
Publisher: IEEE
 
» Exploiting Spatiotemporal Correlation for Wireless Networks Under Interference
Abstract:
This paper starts from an empirical observation on the existence of spatiotemporal correlation among nearby wireless links within short time intervals. The phenomenon due to correlated interference has become pervasive with densely deployed wireless devices, causing potential errors in existing popular metrics built upon the assumption of link independence. To this end, we propose correlated ETX (cETX), which generalizes the widely-adopted ETX to maintain the accuracy under correlated links. To the best of our knowledge, this is the first work to introduce a unified metric embracing both temporal and spatiotemporal correlations. As a generalized metric, the highlight of our work is the broad applicability and effectiveness–extensive evaluations on ZigBee (802.15.4) and Wi-Fi (802.11b/g/n) testbeds deployed in a lab, corridor, and on a bridge reveal that: simply replacing ETX with cETX: 1) cuts down the error by 62.1%–70.2% and 2) saves averages of 22% and 37% communication cost in three unicast and nine broadcast protocols, respectively, under only 0.7% additional overhead.
Autors: Song Min Kim;Shuai Wang;Tian He;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Oct 2017, volume: 25, issue:5, pages: 3132 - 3145
Publisher: IEEE
 
» Exploring Consensus RNA Substructural Patterns Using Subgraph Mining
Abstract:
Frequently recurring RNAquery id="Q1"> structural motifs play important roles in RNA folding process and interaction with other molecules. Traditional index-based and shape-based schemas are useful in modeling RNA secondary structures but ignore the structural discrepancy of individual RNA family member. Further, the in-depth analysis of underlying substructure pattern is insufficient due to varied and unnormalized substructure data. This prevents us from understanding RNAs functions and their inherent synergistic regulation networks. This article thus proposes a novel labeled graph-based algorithm RnaGraph to uncover frequently RNA substructure patterns. Attribute data and graph data are combined to characterize diverse substructures and their correlations, respectively. Further, a top-k graph pattern mining algorithm is developed to extract interesting substructure motifs by integrating frequency and similarity. The experimental results show that our methods assist in not only modelling complex RNA secondary structures but also identifying hidden but interesting RNA substructure patterns.
Autors: Qingfeng Chen;Chaowang Lan;Baoshan Chen;Lusheng Wang;Jinyan Li;Chengqi Zhang;
Appeared in: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Publication date: Oct 2017, volume: 14, issue:5, pages: 1134 - 1146
Publisher: IEEE
 
» Exploring High Quality Chaotic Signal Generation in a Mutually Delay Coupled Semiconductor Lasers System
Abstract:
High quality chaotic signal generation in a mutually delay coupled semiconductor lasers (MDC-SLs) system is numerically explored by evaluating the time-delay signature (TDS) and complexity of chaotic signals. Autocorrelation function is utilized for quantitatively identifying the TDS of chaotic signal, and Kolmogorov–Sinai entropy and Kaplan–York dimensions are applied to estimate the complexity of chaotic signal. The results show that, under suitable parameters, two sets of chaotic signals with weak TDS and high complexity can be obtained simultaneously. By analyzing the influences of the mutual coupling strength and frequency detuning between the two MDC-SLs on the TDS and complexity of chaotic signals, the optimized parameter regions are specified for simultaneously generating two sets of high quality chaotic signals based on the MDC-SLs system.
Autors: Yu-Shuang Hou;Li-Lin Yi;Guang-Qiong Xia;Zheng-Mao Wu;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 10
Publisher: IEEE
 
» Exploring the LCL Characteristics in GaN-Based Single-L Quasi-Z-Source Grid-Tied Inverters
Abstract:
As more widebandgap (WBG) devices are becoming commercially available, it is beneficial to use WBG device to increase the switching frequency in order to reduce the passive components. For quasi-Z-Source (qZS) grid-tied inverters, the reduction of passive components raises stability concerns as the coupling effect between the dc side and ac side of qZS inverter will increase. In this paper, the coupling effect between qZS impedance network and the output filter is analyzed by modeling both dc and ac sides. Analysis reveals the resonant characteristic of the qZS inverter. Controller parameter boundaries are derived, and a design method to improve stability is then proposed. Case studies for a 2.5-kW 10-kHz Si-based qZS inverter and a 1-kW 100-kHz GaN-based qZS inverter are presented. Circuit simulations and experimental verifications results are provided to assess analysis and the control design.
Autors: Yanjun Shi;Thierry Kayiranga;Yuan Li;Hui Li;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 7758 - 7768
Publisher: IEEE
 
» Exploring Viewer Gazing Patterns for Touch-Based Mobile Gamecasting
Abstract:
Recent years have witnessed an explosion of gamecasting applications, in which game players (or gamers in short) broadcast game playthroughs by their personal devices in real time. Such pioneer platforms, such as YouTube Gaming, Twitch, and Mobcrush, have attracted a massive number of online broadcasters, and each of them can have hundreds or thousands of fellow viewers. The growing number, however, has created significant challenges to the network and end-devices, particularly considering that bandwidth- and battery-limited smartphones or tablets are becoming dominating for both gamers and viewers. Yet the unique touch operations of the mobile interface offer opportunities, too. In this paper, our measurements based on the real traces from gamers and viewers reveal that strong associations exist between the gamers’ touch interactions and the viewers’ gazing patterns. Motivated by this, we present a novel interaction-aware optimization framework to improve the energy utilization and stream quality for mobile gamecasting. Our framework incorporates a touch-assisted prediction module to extract association rules for gazing pattern prediction and a tile-based optimization module to utilize energy on mobile devices efficiently. Trace-driven simulations illustrate the effectiveness of our framework in terms of energy consumption and stream quality. Our user study experiments also demonstrate much improved (3%–13%) quality satisfaction over the state-of-the-art solution with similar network resources.
Autors: Cong Zhang;Qiyun He;Jiangchuan Liu;Zhi Wang;
Appeared in: IEEE Transactions on Multimedia
Publication date: Oct 2017, volume: 19, issue:10, pages: 2333 - 2344
Publisher: IEEE
 
» Extended Kalman Filter for Multichannel InSAR Height Reconstruction
Abstract:
One of the main challenges in Interferometric Synthetic Aperture Radar (SAR) is the accurate height reconstruction of the observed scene. Recently, approaches based on Extended Kalman Filter (EKF) have been proposed. Most of them are based on the hypothesis of height profile continuity. Such condition greatly reduces their applicability, being only valid for particular scenarios. Within this paper, we present a novel Kalman-based height reconstruction approach, specifically designed to work with multichannel data related to any type of scenario, both smooth or sharp. The novelty of the technique consists in its ability in detecting and correctly handling sharp height discontinuities while regularizing smooth areas. The approach is able to maintain the high computational efficiency typical of EKF and to work in an almost unsupervised way. The methodology has been tested and validated on both simulated and real X-band (TerraSAR-X and COSMO-SkyMed) high-resolution data sets. Reported results are encouraging and interesting, showing the correctness and the validity of the proposed approach.
Autors: Roberto Ambrosino;Fabio Baselice;Giampaolo Ferraioli;Gilda Schirinzi;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5854 - 5863
Publisher: IEEE
 
» Fabrication and Electromechanical Modeling of a Flexural-Mode MEMS Piezoelectric Transformer in AlN
Abstract:
This paper presents the fabrication and electromechanical characterization of a novel AlN-based microelectromechanical systems (MEMS) flexural-mode piezoelectric transformer (PT) realized in a silicon-on-insulator bulk-micromachining process with segmented electrodes at the secondary side, which are series-connected in order to increase the output voltage. The goal of this work is to propose a MEMS-based alternative to inductors and magnetic transformers for power management in micro-power mm-scale electronic systems. The fabricated device is fully modeled by means of the Butterworth-Van Dyke (BVD) two-port network. The device is modeled analytically with the classic equations of a fully clamped-edge membrane and through finite-element method simulations. Characterization is performed through impedance measurements and an alternative empirical method suitable for MEMS devices is proposed for directly extracting its lumped parameters electromechanical circuit. Finally, the effect of the feed-through capacitance is fully analytically modeled, and this paper presents a variant of the BVD network of the PT with an inner BVD circuit, allowing an easier estimation of the effects of the complex zeros introduced by the feed-forward capacitance. The presented device achieves a measured maximum voltage gain of 58mV/V at ~36.3 kHz and maximum efficiency of ~75%.
Autors: Antonio Camarda;Guido Sordo;Jacopo Iannacci;Michael Schneider;Ulrich Schmid;Marco Tartagni;Aldo Romani;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Oct 2017, volume: 26, issue:5, pages: 1110 - 1121
Publisher: IEEE
 
» Fabrication, Characterization, and Analysis of Ge/GeSn Heterojunction p-Type Tunnel Transistors
Abstract:
We present a detailed study on fabrication and characterization of Ge/GeSn heterojunction p-type tunnel-field-effect-transistors (TFETs). Critical process modules as high-k stack and p-i-n diodes are addressed individually. As a result an ultrathin equivalent oxide thickness of 0.84 nm with an accumulation capacitance of /cm2 was achieved on an extremely scaled tri-layer stack of GeSnOx/Al2O3/HfO2 deposited by atomic-layer deposition monitored in situ by spectroscopic ellipsometry. Combining these process modules, Ge/GeSn heterojunction pTFETs are fabricated and characterized to demonstrate the best in-class pTFET performance in the GeSn material system. The transfer characteristics of the TFETs show signatures of the trap-assisted thermal generation in the subthreshold regime which is explained by a modified Shockley–Read–Hall model. For the ON-state current, we used band-to-band tunneling models calculated using parameters from the density functional theory. We then use the calibrated model to project performance of GeSn pTFETs with increased Sn content (lower bandgap), reduced trap density and ultrathin body geometry. Both experimental and projected results are benchmarked against state-of-the art III–V (e.g., In0.65Ga0.35/GaAs0.4Sb0.6) pTFETs. We demonstrate the ability of GeSn to achieve superior performance with both high ON-current and sub-60mV/decade switching benefiting from the small and direct bandgap for higher Sn contents.
Autors: Christian Schulte-Braucks;Rahul Pandey;Redwan Noor Sajjad;Mike Barth;Ram Krishna Ghosh;Ben Grisafe;Pankaj Sharma;Nils von den Driesch;Anurag Vohra;Gilbert Bruce Rayner;Roger Loo;Siegfried Mantl;Dan Buca;Chih-Chieh Yeh;Cheng-Hsien Wu;Wilman Tsai;Dimit
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4354 - 4362
Publisher: IEEE
 
» Face Recognition with Occlusion using a wireframe model and Support Vector Machine
Abstract:
This paper proposes a face recognition system with the capacity of achieving high recognition rates, even if the face image presents significant occlusion, using a wireframe model and a Facefit tool that acquires a coordinate system with fiducial points that characterize the facial parts. Thereby, the occlusions are emulated by the selection of points that represent four cases of partial blockage of the face such as: occlusion in eyes area, occlusion in the area of mouth and occlusion in left and right part of face in a separately way. Computer simulations show that the proposed system provides recognition rates higher than 95% in each case, providing also stability to the identification system. Thus, the wireframe model presents a robust coordinate system that even in complex cases, as data loss, is able to obtain a fairly good recognition rate.
Autors: Elizabeth Garcia Rios;Enrique Escamilla Hernandez;Mariko Nakano Miyatake;Hector Perez Meana;
Appeared in: IEEE Latin America Transactions
Publication date: Oct 2017, volume: 15, issue:10, pages: 1960 - 1966
Publisher: IEEE
 
» Facilitating the Integration of Renewables in Latin America: The Role of Hydropower Generation and Other Energy Storage Technologies
Abstract:
It is well known that storage facilities can provide value to various electricity sectors through several services, which we group into five main classes.
Autors: Rodrigo Moreno;Rafael Ferreira;Luiz Barroso;Hugh Rudnick;Eduardo Pereira;
Appeared in: IEEE Power and Energy Magazine
Publication date: Oct 2017, volume: 15, issue:5, pages: 68 - 80
Publisher: IEEE
 
» Facilitating Time Critical Information Seeking in Social Media
Abstract:
Social media plays a major role in helping people affected by natural calamities. These people use social media to request information and help in situations where time is a critical commodity. However, generic social media platforms like Twitter and Facebook are not conducive for obtaining answers promptly. Algorithms to ensure prompt responders for questions in social media have to understand and model the factors affecting their response time. In this paper, we draw from sociological studies on information seeking and organizational behavior to identify users who can provide timely and relevant responses to questions posted on social media. We first draw from these theories to model the future availability and past response behavior of the candidate responders and integrate these criteria with user relevance. We propose a learning algorithm from these criteria to derive optimal rankings of responders for a given question. We present questions posted on Twitter as a form of information seeking activity in social media and use them to evaluate our framework. Our experiments demonstrate that the proposed framework is useful in identifying timely and relevant responders for questions in social media.
Autors: Suhas Ranganath;Suhang Wang;Xia Hu;Jiliang Tang;Huan Liu;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Oct 2017, volume: 29, issue:10, pages: 2197 - 2209
Publisher: IEEE
 
» Falling Water, Rising Power
Abstract:
Hydropower is the production of electricity utilizing the force of falling water. Hydroelectric generators typically found in the United States range greatly in capacity from microhydro units rated between 5 kW-100 kW up to the large units at Grand Coulee Dam in Washington state, which are rated at 805 MW. The newly constructed Three Gorges Dam in China houses 32 units rated at 700 MW as well as two units rated at 50 MW to power the plant itself. Three Gorges is the world's largest hydroelectric power plant in terms of installed electrical generating capacity. Hydropower production can vary throughout the year as water supplies fluctuate. Peak hydropower generation typically occurs during the spring and summer months during snow melt and rain run-off season.
Autors: Mark Skoric;
Appeared in: IEEE Potentials
Publication date: Oct 2017, volume: 36, issue:5, pages: 30 - 31
Publisher: IEEE
 
» Fano Resonance in a Metasurface Composed of Graphene Ribbon Superlattice
Abstract:
We present a metasurface composed of graphene ribbon superlattice that supports plasmonic Fano resonance in a simple symmetric configuration. Without the necessity of changing the geometry size of graphene ribbons, we tune the Fano resonance of the metasurface containing identical graphene ribbons by simply changing the global or local periods of the superlattice. The increase of the global period of the superlattice leads to a blue-shift of the broad resonance of the bright mode, while the increase of the local period leads to simultaneous shifts of the broad resonance of the bright mode and the sharp resonance of the dark mode toward opposite direction with respect to each other. The resonance shift mechanism can be well explained by the restoring force model for longitudinal dipole arrays. In addition, the overall spectral position of the Fano resonance can be actively tuned by the fermi level of graphene ribbons. Our methods provide a simple and flexible pathway to tune the plasmonic Fano resonance, which holds great potentials for tunable biosensing and slow light applications with improved performance.
Autors: Zi-Lan Deng;Xiangping Li;Tao Fu;Guo Ping Wang;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 7
Publisher: IEEE
 
» Fast and Accurate Frequency-Dependent Behavioral Model of Bonding Wires
Abstract:
A proposed model of bonding wires is presented in this paper. For a regular double-π bonding-wire model considering the skin effect, nine parameters should be determined, including inductance , series parasitic resistances , shunt parasitic capacitances , and parameters for skin effects , so procedures to extract the design parameters for a bonding-wire model are complicated. To reduce the complexity, a proposed model is presented. Introducing a frequency-dependent resistor can significantly reduce the number of design parameters for a bonding-wire model considering the skin effect from nine to five. This can resolve the design complexity of the bonding wires and cables. Moreover, it is suitable for industrial applications. In addition, the proposed design methodology is presented and the mechanisms are validated by experiments. According to experimental results, the model accuracy with 10% difference in magnitude between measured and modeled of the 2, 4, 6, and 8 mm aluminum bonding wires is at the frequencies of 5.9, 5.0, 3.5, and 2.9 GHz, respectively.
Autors: To-Po Wang;You-Fu Lu;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2389 - 2396
Publisher: IEEE
 
» Fast Antenna Far-Field Characterization via Sparse Spherical Harmonic Expansion
Abstract:
A procedure is proposed to significantly reduce the amount of time to characterize 3-D antenna far-field patterns. The measured far field is expanded into spherical harmonics, and a sparse recovery algorithm is used to recover the spherical wave coefficients giving access to the field radiated by the antenna everywhere. A small number of measurement points are required, since the relevant information of the most antenna patterns is concentrated in only a few spherical wave coefficients. Sampling strategies enabling fast spherical scans are discussed, which makes the approach both efficient and easy to implement in existing far-field measurement facilities. Simulations are first provided to show the potentialities of this compressive sensing-based approach. The proposed strategy is then applied to characterize 3-D far-field patterns radiated by several antennas operating in different frequency bands measured in far field in direct line of sight configuration and in a compact antenna test range. Experimental results show that a saving in the number of measurement points up to 70% can be achieved compared with standard approaches. These results pave the way to a more efficient use of far-field measurement facilities.
Autors: Benjamin Fuchs;Laurent Le Coq;Sébastien Rondineau;Marco Donald Migliore;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5503 - 5510
Publisher: IEEE
 
» Fast Background Calibration of Sampling Timing Skew in SHA-Less Pipeline ADCs
Abstract:
This brief presents a digital calibration technique for compensating timing-skew errors between the sub-ADC and the MDAC in the first stage of sample-and-hold amplifier (SHA)-less pipeline ADCs. In the presence of clock-skew errors, sub-ADC comparators produce time-variant offsets depending on the input-signal slope at the sampling instants. These increase residue excursions at the MDAC output, potentially causing overranging and an increment in nonlinear errors. This paper derives close analytical expressions for these effects. The proposed method uses the overranging information to perform a low-cost estimation and correction of the skew error with the following features: 1) very fast convergence (in the order of 1-k input samples); 2) indirect evaluation of the skew error signal, without any previous knowledge of the input signal’s frequency distribution; and 3) relatively simple digital logic—basically, two digital comparators and one small accumulator. The method was verified in behavioral and transistor-level simulations. As a demonstrator, its implementation in a 1.8-V 80-dB SNDR 100-Msps SHA-less pipeline ADC in a 0.18- CMOS process is shown.
Autors: A. J. Ginés;E. J. Peralías;A. Rueda;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Oct 2017, volume: 25, issue:10, pages: 2966 - 2970
Publisher: IEEE
 
» Fast Binary Counters Based on Symmetric Stacking
Abstract:
In this brief, a new binary counter design is proposed. It uses 3-bit stacking circuits, which group all of the “1” bits together, followed by a novel symmetric method to combine pairs of 3-bit stacks into 6-bit stacks. The bit stacks are then converted to binary counts, producing 6:3 counter circuits with no xor gates on the critical path. This avoidance of xor gates results in faster designs with efficient power and area utilization. In VLSI simulations, the proposed counters are 30% faster than existing parallel counters and also consume less power than other higher order counters. Additionally, using the proposed counters in existing counter-based Wallace tree multiplier architectures reduces latency and power consumption for 64 and 128-bit multipliers.
Autors: Christopher Fritz;Adly T. Fam;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Oct 2017, volume: 25, issue:10, pages: 2971 - 2975
Publisher: IEEE
 
» Fast Depth Imaging Denoising With the Temporal Correlation of Photons
Abstract:
This paper proposes a novel method to filter out the false alarm of LiDAR system by using the temporal correlation of target reflected photons. Because of the inevitable noise, which is due to background light and dark counts of the detector, the depth imaging of LiDAR system exists a large estimation error. Our method combines the Poisson statistical model with the different distribution feature of signal and noise in the time axis. Due to selecting a proper threshold, our method can effectively filter out the false alarm of system and use the ToFs of detected signal photons to rebuild the depth image of the scene. The experimental results reveal that by our method it can fast distinguish the distance between two close objects, which is confused due to the high background noise, and acquire the accurate depth image of the scene. Our method need not increase the complexity of the system and is useful in power-limited depth imaging.
Autors: Zhenchao Feng;Weiji He;Jian Fang;Guohua Gu;Qian Chen;Ping Zhang;Yuanjin Chen;Beibei Zhou;Minhua Zhou;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 10
Publisher: IEEE
 
» Fast Detection of Compressively Sensed IR Targets Using Stochastically Trained Least Squares and Compressed Quadratic Correlation Filters
Abstract:
Target detection of potential threats at night can be deployed on a costly infrared focal plane array with high resolution. Due to the compressibility of infrared image patches, the high resolution requirement could be reduced with target detection capability preserved. For this reason, a compressive midwave infrared imager (MWIR) with a low-resolution focal plane array has been developed. As the most probable coefficient indices of the support set of the infrared image patches could be learned from the training data, we develop stochastically trained least squares (STLS) for MWIR image reconstruction. Quadratic correlation filters (QCF) have been shown to be effective for target detection and there are several methods for designing a filter. Using the same measurement matrix as in STLS, we construct a compressed quadratic correlation filter (CQCF) employing filter designs for compressed infrared target detection. We apply CQCF to the U.S. Army Night Vision and Electronic Sensors Directorate dataset. Numerical simulations show that the recognition performance of our algorithm matches that of the standard full reconstruction methods, but at a fraction of the execution time.
Autors: Brian Millikan;Aritra Dutta;Qiyu Sun;Hassan Foroosh;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Oct 2017, volume: 53, issue:5, pages: 2449 - 2461
Publisher: IEEE
 
» Fast ISAR Imaging Based on Enhanced Sparse Representation Model
Abstract:
Traditional sparse representation-(SR) based inverse synthetic aperture radar (ISAR) imaging schemes can achieve significant performance, but they suffer from high costs of memory and computational complexity, because the SR of a 2-D image is converted into that of a 1-D vector. Instead of memory consuming vector operations, we propose a fast ISAR imaging algorithm, where the decomposition and reconstruction of a 2-D scene is implemented using matrix operations directly. Besides the spatial sparsity of a scene, its structural sparsity is presented using the range profile of the scene, where both can be used to enhance sparsity exploitation during image reconstruction. Also, benefitting from the structural sparsity of the range profile, the target energy can be accumulated during the process, which further improves performance. Compared to available SR-based ISAR imaging algorithms, the proposed algorithm reduces both memory costs and computational complexity significantly, which is proven using simulated and real data.
Autors: Guanghui Zhao;Fangfang Shen;Jie Lin;Guangming Shi;Yi Niu;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5453 - 5461
Publisher: IEEE
 
» Fast Parallel Path Concatenation for Graph Extraction
Abstract:
Heterogeneous graph is a popular data model to represent the real-world relations with abundant semantics. To analyze heterogeneous graphs, an important step is extracting homogeneous graphs from the heterogeneous graphs, called homogeneous graph extraction. In an extracted homogeneous graph, the relation is defined by a line pattern on the heterogeneous graph and the new attribute values of the relation are calculated by user-defined aggregate functions. The key challenges of the extraction problem are how to efficiently enumerate paths matched by the line pattern and aggregate values for each pair of vertices from the matched paths. To address above two challenges, we propose a parallel graph extraction framework, where we use vertex-centric model to enumerate paths and compute aggregate functions in parallel. The framework compiles the line pattern into a path concatenation plan, which determines the order of concatenating paths and generates the final paths in a divide-and-conquer manner. We introduce a cost model to estimate the cost of a plan and discuss three plan selection strategies, among which the best plan can enumerate paths in iterations, where is the length of a pattern. Furthermore, to improve the performance of evaluating aggregate functions, we classify the aggregate functions into three categories, i.e., distributive aggregation, algebraic aggregation, and holistic aggregation. Since the distributive and algebraic aggregations can be computed from the partial paths, we speed up the aggregation by computing partial aggregate values during the path enumeration.
Autors: Yingxia Shao;Kai Lei;Lei Chen;Zi Huang;Bin Cui;Zhongyi Liu;Yunhai Tong;Jin Xu;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Oct 2017, volume: 29, issue:10, pages: 2210 - 2222
Publisher: IEEE
 
» Fast Real-Time Causal Linewise Progressive Hyperspectral Anomaly Detection via Cholesky Decomposition
Abstract:
Real-time processing of anomaly detection has become one of the most important issues in hyperspectral remote sensing. Due to the fact that most widely used hyperspectral imaging spectrometers work in a pushbroom fashion, it is necessary to process the incoming data line in a causal linewise progressive manner with no future data involved. In this study, we proposed several processes to well improve the computational performance of real-time causal linewise progressive anomaly detection (RCLP-AD). At first, Cholesky decomposition along with linear system solving (CDLSS) was used since the background statistical matrix are symmetric positive definite. The computational performance as well as the numerical stabilities is well improved. In order to show the computational advantage of the proposed method, we did a comprehensive comparative analysis regarding the computational complexity of different linewise processing techniques, in terms of the theoretical floating point operations (flops) and the real computer processing time. Moreover, the symmetric property of some intermediate resulting matrices in the process is considered for further computational optimization. Finally, from an onboard detection point of view, we defined the line-varying global background (i.e., an area covered by recently acquired data lines) to improve the detection power. To substantiate the performance of the CDLSS-based RCLP-AD regarding the accuracy and efficiency, two hyperspectral datasets were used in our experiments.
Autors: Lifu Zhang;Bo Peng;Feizhou Zhang;Lizhe Wang;Hongming Zhang;Peng Zhang;Qingxi Tong;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Oct 2017, volume: 10, issue:10, pages: 4614 - 4629
Publisher: IEEE
 
» Fast Rise Time High Current Electron Beam: Emission, Acceleration, and Drift Motion
Abstract:
Fast processes associated with emission, acceleration, and drift motion of a high current, moderately magnetized electron beam (particles energy ~300 keV; current ~3 kA) were studied experimentally when tubular explosive-emission cathode was supplied by subnanosecond rise time voltage pulse. Kinematic effect causes the sharpening of the observed beam front which was proven by particle-in-cell numerical modeling. The angular structure of tubular beam was studied through the current waveform records from collector probe after beam propagation through a radial-slit collimator. Current waveforms had time resolution no worse than 10 ps and provided the analysis of the beam temporal structure after its acceleration as well as in the process of further electrons drift motion in a finite guiding magnetic field.
Autors: Sergei A. Shunailov;Gennady A. Mesyats;Ilya V. Romanchenko;Vladislav V. Rostov;Konstantin A. Sharypov;Valery G. Shpak;Marat R. Ul’maskulov;Michael I. Yalandin;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Oct 2017, volume: 45, issue:10, pages: 2755 - 2761
Publisher: IEEE
 
» Fast Semiconductor Switching Modules for Transformer-Coupled LC Inversion Generators
Abstract:
The recent availability of fast high-power semiconductor switches makes the transformer coupled LC inversion generator (TCLCG) topology a very promising candidate for the realization of reliable, multi-kHz repetition rate pulse generators with an output voltage in the range of 200 kV and more. Usage of 1:1 transformers instead of closing switches in each generator stage reduces the total number of switches inside the TCLCG to only one, independent of the numbers of stages. Thus, problem of synchronization as in Marx-generators or classical LC inversion generators can be omitted. In principle, capacitors are initially charged to the charging voltage, whereas the odd-numbered of each stage are charged with the opposite polarity to the even-numbered capacitors. Fast voltage inversion of the even-numbered capacitors leads to efficient voltage multiplication provided the semiconductor switching module will be sufficiently fast to minimize switching losses. For initial investigations, a special asymmetrically compensated three-stage test TCLCG was designed and set up. Three high-voltage semiconductor switching modules were experimentally tested in detail; two 20-kV high-voltage switching modules consisting of a series arrangement of 15 Si-based insulated gate bipolar transistors or 15 SiC-based MOSFETs, with in each case 1700-V breakdown voltage, and a fast experimental 10-kV thyristor switching module with kilo ampere current carrying capability. The achievable output signal rise time and generator efficiency for different electrical loads (resistive, capacitive, or inductive) are discussed.
Autors: Rainer Bischoff;Volker Brommer;Meik Stoll;Sigo Scharnholz;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Oct 2017, volume: 45, issue:10, pages: 2618 - 2622
Publisher: IEEE
 
» Fast Simulation of Dynamic Ultrasound Images Using the GPU
Abstract:
Simulated ultrasound data is a valuable tool for development and validation of quantitative image analysis methods in echocardiography. Unfortunately, simulation time can become prohibitive for phantoms consisting of a large number of point scatterers. The COLE algorithm by Gao et al. is a fast convolution-based simulator that trades simulation accuracy for improved speed. We present highly efficient parallelized CPU and GPU implementations of the COLE algorithm with an emphasis on dynamic simulations involving moving point scatterers. We argue that it is crucial to minimize the amount of data transfers from the CPU to achieve good performance on the GPU. We achieve this by storing the complete trajectories of the dynamic point scatterers as spline curves in the GPU memory. This leads to good efficiency when simulating sequences consisting of a large number of frames, such as B-mode and tissue Doppler data for a full cardiac cycle. In addition, we propose a phase-based subsample delay technique that efficiently eliminates flickering artifacts seen in B-mode sequences when COLE is used without enough temporal oversampling. To assess the performance, we used a laptop computer and a desktop computer, each equipped with a multicore Intel CPU and an NVIDIA GPU. Running the simulator on a high-end TITAN X GPU, we observed two orders of magnitude speedup compared to the parallel CPU version, three orders of magnitude speedup compared to simulation times reported by Gao et al. in their paper on COLE, and a speedup of 27000 times compared to the multithreaded version of Field II, using numbers reported in a paper by Jensen. We hope that by releasing the simulator as an open-source project we will encourage its use and further development.
Autors: Sigurd Storve;Hans Torp;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Oct 2017, volume: 64, issue:10, pages: 1465 - 1477
Publisher: IEEE
 
» Fast Startup of LC VCOs Using Circuit Asymmetries
Abstract:
An LC VCO whose design includes deliberate circuit mismatches is presented. It is shown that such mismatches can reduce the oscillation start-up time due to a common-mode disturbance simultaneous with the turn-on of the tail current. The use of this technique is applied to a low-power transmitter for an ultra-wideband wireless communication system using the on–off keying modulation scheme. Measurements using a 0.18- CMOS technology with a 4.2-GHz carrier frequency demonstrate the technique.
Autors: Joshua H. Kim;Ali Tazarv;Michael M. Green;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Oct 2017, volume: 64, issue:10, pages: 1172 - 1176
Publisher: IEEE
 
» Fast-Lipschitz Power Control and User-Frequency Assignment in Full-Duplex Cellular Networks
Abstract:
In cellular networks, the three-node full-duplex transmission mode has the potential to increase spectral efficiency without requiring full-duplex capability of users. Consequently, three-node full-duplex in cellular networks must deal with self-interference and user-to-user interference, which can be managed by power control and user-frequency assignment techniques. This paper investigates the problem of maximizing the sum spectral efficiency by jointly determining the transmit powers in a distributed fashion, and assigning users to frequency channels. The problem is formulated as a mixed-integer nonlinear problem, which is shown to be non-deterministic polynomial-time hard. We investigate a close-to-optimal solution approach by dividing the joint problem into a power control problem and an assignment problem. The power control problem is solved by Fast-Lipschitz optimization, while a greedy solution with guaranteed performance is developed for the assignment problem. Numerical results indicate that compared with the half-duplex mode, both spectral and energy efficiencies of the system are increased by the proposed algorithm. Moreover, results show that the power control and assignment solutions have important, but opposite roles in scenarios with low or high self-interference cancellation. When the self-interference cancellation is high, user-frequency assignment is more important than power control, while power control is essential at low self-interference cancellation.
Autors: José Mairton B. da Silva;Gábor Fodor;Carlo Fischione;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6672 - 6687
Publisher: IEEE
 
» Fault Detection Over Frequency Region: Generalized Spectral Factorization Approach
Abstract:
We present results on fault detection in presence of disturbances of descriptor systems over a frequency region. Instead of the methodology of the generalized KYP lemma, used in the literature, we use the methodology of generalized spectral factorization. Illustrative examples are given.
Autors: Jovan D. Stefanovski;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5296 - 5301
Publisher: IEEE
 
» Fault Diagnosis of Space-Borne Fiber-Optic Gyros Based on Random Walk Coefficient Prediction and In-Orbit Calculation
Abstract:
A novel fault diagnosis method for the space-borne interferometric fiber-optic gyroscope (IFOG) is presented in this paper. The noise source of the fiber-optic gyroscope is analyzed first. Then, the prediction model of the random walk coefficient (RWC) is established based on the radiation-induced attenuation effect on optical fiber, and the estimation model of RWC is developed by using the detected signal acquired by the photo-detector. In addition, an improved iterative method to calculate the RWC with the output data of the IFOG in orbit is proposed. The three RWC values mentioned above are compared to determine the operational state of the gyroscope. And an in-situ fault diagnosis strategy for the IFOG is proposed finally. Based on the ground simulation and fault injection, the feasibility of the strategy is proved.
Autors: Jing Jin;Ting Zhang;Kun Ma;Haoshi Zhang;Fei Teng;Shaobo Zhang;
Appeared in: IEEE Sensors Journal
Publication date: Oct 2017, volume: 17, issue:20, pages: 6637 - 6645
Publisher: IEEE
 
» Fault Tolerance Capability and Semiconductor’s Hold-Off Voltage of Solid-State Bipolar Marx Modulators
Abstract:
Two solid-state bipolar Marx modulators are analyzed and compared regarding hold-off semiconductor voltages and open-fault tolerance capability. Normal and abnormal operating conditions are considered, such as switch synchronization mismatches, failures, and open faults. Ten-stage laboratory prototypes of two bipolar Marx modulators have been assembled using 1200-V insulated gate bipolar transistors and matching diodes, to operate at 500-V dc input voltage. Outputs are 4-kV bipolar pulses, 1% duty ratio, into resistive loads, and 1-kHz frequency. Lack of synchronization and open-fault tests confirm that only topologies with redundant switches can operate without semiconductors being subjected to double hold-off voltages while presenting current paths to clear faults.
Autors: Hiren Canacsinh;J. Fernando Silva;L. M. Redondo;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Oct 2017, volume: 45, issue:10, pages: 2661 - 2666
Publisher: IEEE
 
» Feast or Famine [From the Editor's Desk]
Abstract:
Presents the introductory editorial for this issue of the publication.
Autors: Alfy Riddle;
Appeared in: IEEE Microwave Magazine
Publication date: Oct 2017, volume: 18, issue:6, pages: 6 - 22
Publisher: IEEE
 
» Feature-Fused SAR Target Discrimination Using Multiple Convolutional Neural Networks
Abstract:
Target discrimination has been one of the hottest issues in the interpretation of synthetic aperture radar (SAR) images. However, the presence of speckle noise and the absence of robust features make SAR discrimination difficult to deal with. Recently, convolutional neural network has obtained state-of-the-art results in pattern recognition. In this letter, we propose a target discrimination framework that jointly uses intensity and edge information of SAR images. This framework contains three parts, namely, feature extraction block, feature fusion block, and final classification block. In addition, a novel feature fusion method that can preserve the spatial relationship of different features is introduced. Experimental results on the miniSAR data demonstrate the effectiveness of our method.
Autors: Ning Wang;Yinghua Wang;Hongwei Liu;Qunsheng Zuo;Jinglu He;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1695 - 1699
Publisher: IEEE
 
» Feedback Stabilized Optical Fabry–Pérot Interferometer Based on Twin-Core Fiber for Multidimension Microdisplacement Sensing
Abstract:
A novel optical Fabry–Pérot interferometer (FPI) is proposed and experimentally demonstrated for multidimension microdisplacement sensing (MMS). The sensor structure consists of a section of twin-core fiber with a length of 2.4 cm and a section of feedback fiber (FBF) fabricated by normal single-mode fiber. The end faces of two fibers can be formed as the reflection cavity (RC) of the FPI. Mounting the sensor on translation stages, and moving the FBF in different directions to change the RC, the changing mode interference of the reflected beam can be measured. A maximum microdisplacement sensitivity of 0.954 nm/μm with a higher resolution 0.052 μm was achieved. Due to the advantages of the MMS and simple configuration, the sensor is significantly beneficial to practical application.
Autors: Chuanbiao Zhang;Tigang Ning;Jingjing Zheng;Jing Li;Heng Lin;Xuekai Gao;Li Pei;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 9
Publisher: IEEE
 
» Feedback-Based Online Network Coding
Abstract:
Current approaches to the practical implementation of network coding are batch-based, and often do not use feedback, except possibly to signal completion of a file download. In this paper, the various benefits of using feedback in a network coded system are studied. It is shown that network coding can be performed in a completely online manner, without the need for batches or generations, and that such online operation does not affect the throughput. Although these ideas are presented in a single-hop packet erasure broadcast setting, they naturally extend to more general lossy networks, which employ network coding in the presence of feedback. The impact of feedback on sender-side queue size and receiver-side decoding delay is studied in an asymptotic sense as the traffic load approaches capacity. Different notions of decoding delay are considered, including an order-sensitive notion, which assumes that packets are useful only when delivered in order. Strategies for adaptive coding based on feedback are presented. Our scheme achieves throughput optimality and asymptotically optimal sender queue size and is conjectured to achieve asymptotically optimal in-order delivery delay for any number of receivers. This paper may be viewed as a natural extension of Automatic Repeat reQuest to coded networks.
Autors: Jay Kumar Sundararajan;Devavrat Shah;Muriel Médard;Parastoo Sadeghi;
Appeared in: IEEE Transactions on Information Theory
Publication date: Oct 2017, volume: 63, issue:10, pages: 6628 - 6649
Publisher: IEEE
 
» Fekete Points, Formation Control, and the Balancing Problem
Abstract:
We study formation control problems. Our approach is to let a group of systems maximize their pairwise distances while bringing them all to a given submanifold, determining the shape of the formation. The algorithm we propose allows us to initialize the positions of the individual systems in the ambient space of the given submanifold but brings them to the desired formation asymptotically in a stable fashion. Our control inherently consists of a distributed component, maximizing the pairwise distances, and a decentralized component, asymptotically stabilizing the submanifold. We establish a graph-theoretical interpretation of the equilibria that our control enforces and extends our approach to systems living on the special Euclidean group. Throughout this paper, we illustrate our approach on different examples.
Autors: Jan Maximilian Montenbruck;Daniel Zelazo;Frank Allgöwer;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5069 - 5081
Publisher: IEEE
 
» Fermi Level Depinning in Ti/GeO2/n-Ge via the Interfacial Reaction Between Ti and GeO2
Abstract:
A new method of forming an ohmic contact without an increase in parasitic resistance is proposed in the Ti/GeO2/Ge substrate. Fermi-level depinning in Ti/GeO2/n–Ge contacts is possible with the formation of an interfacial TiOx layer in the contacts via an interfacial reaction. Unlike the intentional deposition of a metal oxide on a Ge substrate, this method provides easy process integration to lessen Fermi-level pinning in n-type Ge substrates.
Autors: Yujin Seo;Tae In Lee;Hyun Jun Ahn;Jungmin Moon;Wan Sik Hwang;Hyun-Yong Yu;Byung Jin Cho;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4242 - 4245
Publisher: IEEE
 
» Fiber Optic Magnetic Field Sensor Based on Magnetic Nanoparticle Assembly in Microcapillary Ring Resonator
Abstract:
A magnetic field sensor based on the magnetic-field-induced nanoparticle assembly effect in microcapillary whispering gallery mode (WGM) ring resonator is proposed and experimentally demonstrated. The chemical characteristics of nanoparticles and the silica microcapillary are used to link up the surface density of the resonator and the magnetic field intensity. The magnetic field variation changes the surface density of nanoparticles adsorbed on the sensor surface and respond to the WGM transmission spectra shift. Because of the powerful surface sensing capability of WGM, the maximum sensing sensitivity reaches 57.59 nm/mT and the detection limit reaches 1.39 × 10 –4, respectively. The magnetic field response characteristic of the sensor is studied as well. This provides the potential to fiber-based magnetic field sensing applications.
Autors: Zhe Yu;Junfeng Jiang;Xuezhi Zhang;Kun Liu;Shuang Wang;Wenjie Chen;Tiegen Liu;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 9
Publisher: IEEE
 
» File Updates Under Random/Arbitrary Insertions and Deletions
Abstract:
The problem of one-way file synchronization, henceforth called “file updates”, is studied in this paper. Specifically, a client edits a file, where the edits are modeled by insertions and deletions (InDels). An old copy of the file is stored remotely at a data-centre, and is also available to the client. We consider the problem of throughput- and computationally-efficient communication from the client to the data-centre, to enable the data-centre to update its old copy to the newly edited file. Two models for the source files and edit patterns are studied: the random pre-edit sequence left-to-right random InDel (RPES-LtRRID) process, and the arbitrary pre-edit sequence arbitrary InDel (APES-AID) process. In both models, we consider the regime, in which the number of insertions and deletions is a small (but constant) fraction of the length of the original file. For both models, information-theoretic lower bounds on the best possible compression rates that enable file updates are derived (up to first order terms). Conversely, a simple compression algorithm using dynamic programming (DP) and entropy coding (EC), henceforth called DP-EC algorithm, achieves rates that are within constant additive gap (which diminishes as the alphabet size increases) to information-theoretic lower bounds for both models. For the RPES-LtRRID model, a dynamic-programming-run-length-compression (DP-RLC) algorithm is proposed, which achieves a compression rate matching the information-theoretic lower bound up to first order terms. Therefore, when the insertion and deletion probabilities are small (such that first order terms dominate), the achievable rate by DP-RLC is nearly optimal for the RPES-LtRRID model.
Autors: Qiwen Wang;Sidharth Jaggi;Muriel Médard;Viveck R. Cadambe;Moshe Schwartz;
Appeared in: IEEE Transactions on Information Theory
Publication date: Oct 2017, volume: 63, issue:10, pages: 6487 - 6513
Publisher: IEEE
 
» Filtering Property Based on Ultra-Wide Stopband in Double Sector/Sectorial-Ring Stub Resonator Coupled to Plasmonic Waveguide
Abstract:
A double sector or sectorial-ring stub resonator coupled to a plasmonic waveguide is proposed and investigated. This resonator is built with two same stubs that are symmetrically arranged together, which has the advantages of realizing asymmetrical single stub and forming no-distance double stub. The characteristic spectral responses of the two novel systems are simulated by using the finite-difference time-domain method. The results show that an ultra-wide stopband is achieved, and a multiple double stub is realized by altering the structure size of the double stub that plays important role in the stopband phenomenon. A tunable stopband, a specific filtering waveband and an optimum structural parameter are obtained by adjusting the inner radius (r), (outer) radius (R), or central angle (θ) of the double stub. The wavelength and bandwidth of the stopband have various variations with the changing of r, R, or θ, and the stopbands in the two systems have similar changes and different features. This paper provides a promising application for band-stop nanofilters and plasmonic integrated optical circuits.
Autors: Mingfei Zheng;Hongjian Li;Hui Xu;Zhihui He;Zhiquan Chen;Mingzhuo Zhao;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 8
Publisher: IEEE
 
» Finding Measurement Configurations for Accurate Robot Calibration: Validation With a Cable-Driven Robot
Abstract:
It is well known that, by properly selecting the measurement configurations in robot calibrations, the observability index of unknown parameters can be maximized, leading to high calibration accuracy. For this purpose, many configuration-search methods were proposed. However, the established methods were mainly based on derivative-free or metaheuristic techniques, whose computational costs were high. Moreover, the robustness of observability index and convergences of configuration searches were not investigated. In this paper, by extending a recent result in matrix perturbation theory to robot kinematics, we establish the closed-form mapping from configuration perturbations to singular-value variations. Based on this mapping, an efficient configuration-search method is proposed, the robustness of the observability index under bounded configuration perturbations is analyzed, and the convergence of configuration searches is studied. The proposed methods were validated by simulations on serial and parallel robots. With roughly estimated initial parameters, self-calibration experiments on a redundant cable-driven parallel robot were performed. The effectiveness of the proposed methods is demonstrated by the experiment results.
Autors: Hongbo Wang;Tianqi Gao;Jun Kinugawa;Kazuhiro Kosuge;
Appeared in: IEEE Transactions on Robotics
Publication date: Oct 2017, volume: 33, issue:5, pages: 1156 - 1169
Publisher: IEEE
 
» Fixed-Time Connectivity-Preserving Distributed Average Tracking for Multiagent Systems
Abstract:
This brief studies the fixed-time average tracking problem for multiagent systems under communication constraints, in which each agent has a limited sensing range. A distributed nonlinear control protocol is proposed to make a team of agents track the average of multiple time-varying reference signals with bounded derivatives. Furthermore, the initial interaction patterns can be preserved under the designed protocol and the average tracking can be achieved within fixed time, where the bound of settling time is independent of the initial conditions. Thus, the fixed convergence time can be flexibly adjusted. Finally, some numerical examples are provided to illustrate the performance and effectiveness of the theoretical results.
Autors: Huifen Hong;Wenwu Yu;Xinghuo Yu;Guanghui Wen;Ahmed Alsaedi;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Oct 2017, volume: 64, issue:10, pages: 1192 - 1196
Publisher: IEEE
 
» Flexibility Needed: Challenges for Future Energy Storage Systems [Guest Editorial]
Abstract:
The articles in this special section focus on the technologies that will support future energy storage systems. In modern power systems, we are transitioning to an increasing penetration of massive low-cost wind and solar generation, which will require indispensable system flexibility for balancing requirements to maintain system performance. The existing actors have limited technical capabilities to provide the needed flexibility, and new alternatives are required. The flexibility providers are diverse and being assessed extensively, with a clear sense of urgency.
Autors: Hugh Rudnick;Luiz Barroso;
Appeared in: IEEE Power and Energy Magazine
Publication date: Oct 2017, volume: 15, issue:5, pages: 12 - 19
Publisher: IEEE
 
» Flexible and Fine-Grained Attribute-Based Data Storage in Cloud Computing
Abstract:
With the development of cloud computing, outsourcing data to cloud server attracts lots of attentions. To guarantee the security and achieve flexibly fine-grained file access control, attribute based encryption (ABE) was proposed and used in cloud storage system. However, user revocation is the primary issue in ABE schemes. In this article, we provide a ciphertext-policy attribute based encryption (CP-ABE) scheme with efficient user revocation for cloud storage system. The issue of user revocation can be solved efficiently by introducing the concept of user group. When any user leaves, the group manager will update users’ private keys except for those who have been revoked. Additionally, CP-ABE scheme has heavy computation cost, as it grows linearly with the complexity for the access structure. To reduce the computation cost, we outsource high computation load to cloud service providers without leaking file content and secret keys. Notably, our scheme can withstand collusion attack performed by revoked users cooperating with existing users. We prove the security of our scheme under the divisible computation Diffie-Hellman assumption. The result of our experiment shows computation cost for local devices is relatively low and can be constant. Our scheme is suitable for resource constrained devices.
Autors: Jiguo Li;Wei Yao;Yichen Zhang;Huiling Qian;Jinguang Han;
Appeared in: IEEE Transactions on Services Computing
Publication date: Oct 2017, volume: 10, issue:5, pages: 785 - 796
Publisher: IEEE
 
» Flexible Efficient Top-Emitting Organic Light-Emitting Devices on a Silk Substrate
Abstract:
A flexible efficient top-emitting organic light-emitting device (TOLED) on an off-the-shelf silk substrate has been demonstrated by planarizing the silk substrate with photopolymer NOA63. The flexibility of the bare silk substrates was retained in the planarized silk substrates due to ductile characteristics of cured NOA63. The planarized silk substrate has shown superiority on surface morphology, which is beneficial to the performances of OLEDs. Their maximum luminance and current efficiency are 45545 and 37.7 cd/A, respectively. Moreover, our devices show not only high luminance and efficiency but also high flexibility and mechanical robustness. Emission of operating devices is uniform and free of defects under a very small bending radius and the luminance and efficiency do not deteriorate obviously after repeated bending. TOLEDs on silk substrate are a potential alternative to wearable displays.
Autors: Yue-Feng Liu;Ming-Hui An;Yan-Gang Bi;Da Yin;Jing Feng;Hong-Bo Sun;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 6
Publisher: IEEE
 
» Flexible Low-Power Organic Complementary Inverter Based on Low- ${k}$ Polymer Dielectric
Abstract:
Organic complementary inverters that have high performance, low-power operation, and flexible compatibility are achieved using a simple and low-cost method to prepare a thin low- polymer dielectric on sputtered C nanoparticles. The operation voltage of the flexible inverter can be as low as 3 V, and the gain is close to 200, which is superior to most reported organic-based inverters. The flexible inverter also exhibits outstanding switching stability in multiple signal processing. The present organic inverters may be of value in portable and wearable electronics.
Autors: Jie Liu;Xu Gao;Jian-Long Xu;Antonio Ruotolo;Sui-Dong Wang;
Appeared in: IEEE Electron Device Letters
Publication date: Oct 2017, volume: 38, issue:10, pages: 1461 - 1464
Publisher: IEEE
 
» Flexible PCC Voltage Unbalance Compensation Strategy for Autonomous Operation of Parallel DFIGs
Abstract:
This paper proposes a flexible compensation strategy for parallel-connected doubly fed induction generators (DFIGs) when connected to an unbalanced weak grid. The proposed strategy has two main advantages, the voltage unbalance factor at the point of common coupling (PCC) can be continuously controlled, thus, the flexible tradeoff between the balanced DFIG output current and the balanced PCC voltage can be achieved, and the negative sequence current required by the compensation can be properly shared among the parallel DFIGs and their grid side converters according to their respective operation conditions without the need of real-time communication. The operation performance and stability of the proposed strategy are analyzed. Simulation and experimental results are carried out to verify the proposed compensation strategy.
Autors: Tao Wang;Heng Nian;Z. Q. Zhu;Hongyang Huang;Xiaoming Huang;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4807 - 4820
Publisher: IEEE
 
» Flexible Tactile Sensor Array Mounted on the Curved Surface: Analytical Modeling and Experimental Validation
Abstract:
This paper presents an analytical model to study the sensing performance of the flexible capacitive tactile sensor array when mounted on a curved surface. To predict the deformation of the sensor unit, a cylindrical coordinate is constructed for the upper Polyethylene Terephthalate (PET) and truncated pyramids dielectric layer. The displacement functions model is developed and solved by using the Ritz method. Then, this model is utilized to investigate the capacitance change of the sensor unit and the model-calculated results are compared with the experiment data. Both model calculated and experiment measured results indicate that the capacitances of the sensor array are increased by about 30% when the sensor is mounted on the curved surface with a radius of curvature of 10 mm. Due to the bending effects of the curved surface, the sensitivities of the sensor array are decreased based on the model calculation and are confirmed by experimental validation. Thus, results demonstrate that the developed analytical model can accurately predict the sensing performance of the tactile sensor array on the curved surface and could be utilized for the real applications. [2016-0235]
Autors: Yancheng Wang;Guanhao Liang;Deqing Mei;Zichen Chen;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Oct 2017, volume: 26, issue:5, pages: 1002 - 1011
Publisher: IEEE
 
» Floating Monopole Antenna on a Tethered Subsurface Sensor at 433 MHz for Ocean Monitoring Applications
Abstract:
Low-cost tethered buoys are important for seawater observation, coastal area monitoring, and pollution sensing. Underwater sensor networks operating at 433 MHz (ISM band) suffer high attenuation due to seawater conductivity. Significant propagation distance cannot be achieved through seawater or along the seabed. This paper reports a novel technique for communication between sensors operating in shallow water. A sensor tethered to the bottom was connected to a floating monopole antenna via an insulated wire transmission line. Experiments and calculations show that the attenuation along the transmission line was 38 dB/m. Surface propagation for buoy-to-base station was approximately 1 dB/m with a communication range of 30 m using a 10-dBm transmitter circuit with receiver sensitivity of 110 dBm. For buoy to buoy the surface propagation was measured as 3.5 dB/m with a communication range of 4 m. Experiments were carried out in calm water conditions. The results demonstrate that significant sensor network coverage of coastal regions is possible.
Autors: Zia M. Loni;Hugo G. Espinosa;David V. Thiel;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Oct 2017, volume: 42, issue:4, pages: 818 - 825
Publisher: IEEE
 
» Flocking of the Cucker-Smale Model on General Digraphs
Abstract:
In the literature, the study of the Cucker-Smale (C-S) flocking model is all restricted to connected undirected graphs or digraphs of some special types, containing only a single root. In this technical note, we establish the flocking behavior of the C-S model on general digraphs, which contain all existing interaction topologies in relation to the C-S model as special cases. In particular, the topology with multiple leaders is included. The flocking results are guaranteed under some conditions on the initial state of the flock only. The critical exponent below which unconditional convergence holds is given, depending only on the interaction topology. It is consistent with the ones obtained under some known special topologies in the literature.
Autors: Jiu-Gang Dong;Li Qiu;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5234 - 5239
Publisher: IEEE
 
» Fog-Aided Wireless Networks for Content Delivery: Fundamental Latency Tradeoffs
Abstract:
A fog-aided wireless network architecture is studied in which edge nodes (ENs), such as base stations, are connected to a cloud processor via dedicated fronthaul links while also being endowed with caches. Cloud processing enables the centralized implementation of cooperative transmission strategies at the ENs, albeit at the cost of an increased latency due to fronthaul transfer. In contrast, the proactive caching of popular content at the ENs allows for the low-latency delivery of the cached files, but with generally limited opportunities for cooperative transmission among the ENs. The interplay between cloud processing and edge caching is addressed from an information-theoretic viewpoint by investigating the fundamental limits of a high signal-to-noise-ratio metric, termed normalized delivery time (NDT), which captures the worst case coding latency for delivering any requested content to the users. The NDT is defined under the assumptions of either serial or pipelined fronthaul-edge transmission, and is studied as a function of fronthaul and cache capacity constraints. Placement and delivery strategies across both fronthaul and wireless, or edge, segments are proposed with the aim of minimizing the NDT. Information-theoretic lower bounds on the NDT are also derived. Achievability arguments and lower bounds are leveraged to characterize the minimal NDT in a number of important special cases, including systems with no caching capabilities, as well as to prove that the proposed schemes achieve optimality within a constant multiplicative factor of 2 for all values of the problem parameters.
Autors: Avik Sengupta;Ravi Tandon;Osvaldo Simeone;
Appeared in: IEEE Transactions on Information Theory
Publication date: Oct 2017, volume: 63, issue:10, pages: 6650 - 6678
Publisher: IEEE
 
» Foreground Removal Approach for Hole Filling in 3D Video and FVV Synthesis
Abstract:
The depth-image-based rendering is a key technique for 3D video and free viewpoint video synthesis. One of the critical problems in current synthesis methods is that the background (BG) occluded by the foreground objects might be exposed in the new view, and some holes are produced in the synthesized video. However, most of the traditional hole-filling approaches may bring some blurry effect or artifacts in the virtual view. In this paper, a foreground removal approach for hole filling is proposed, in which the foreground objects are removed from both the 2D video and its corresponding depth map, and then a BG video and its depth map are generated before the 3D warping and used to eliminate the holes in the synthesized video. Moreover, a BG extension method is applied in the reference view to prevent the large holes occurring along the border areas in the virtual view. Our analysis and experimental results have indicated that the proposed approach has better performance compared with the other methods in terms of the quality of synthesized video, computational complexity, and running time in multiview synthesis or multiframe synthesis.
Autors: Guibo Luo;Yuesheng Zhu;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Oct 2017, volume: 27, issue:10, pages: 2118 - 2131
Publisher: IEEE
 
» Foreword to the Special Issue on Advances in Ground-Penetrating Radar Research and Applications
Abstract:
Autors: Wallace W. L. Lai;Sébastien Lambot;Jan van der Kruk;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Oct 2017, volume: 10, issue:10, pages: 4271 - 4272
Publisher: IEEE
 
» Fountain-Coded File Spreading Over Mobile Networks
Abstract:
Spreading a large file consisting of many packets over a mobile network is challenging due to the short meeting duration for each transmission. Moreover, two typical causes of inefficient file spreading are duplicate packet reception at the destination nodes and excessive overhead exchanges. We propose to employ fountain codes at the source node to jointly addresses the three issues: 1) each coded packet can be small enough to fit into the meeting duration; 2) duplicate packet reception is significantly reduced since each coded packet is innovative; and 3) overhead is greatly saved by using file-level ACK instead of packet-level ACK. We conduct performance analysis in terms of the source-to-destination file delay and source-to-destination file spreading time in both non-relaying and relaying scenarios. While packet duplication can be eliminated in the former scenario, there is still a non-trivial duplication probability if relaying is allowed. Therefore, we propose a fountain-coded two-hop relaying (FTTR) protocol to further reduce the packet duplication ratio so that the spreading performance does not degrade with network size. The file spreading time and packet duplication ratio of FTTR are derived in closed form and verified through simulations.
Autors: Zhaoyang Zhang;Huazi Zhang;Huaiyu Dai;Xiaoming Chen;Dapeng Oliver Wu;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6766 - 6778
Publisher: IEEE
 
» FPGA Implementation of a Tone-Based Flight Termination System in a Software-Defined Radio Platform
Abstract:
This paper outlines the design and implementation of a tone-based flight termination system (FTS) in a software-defined radio (SDR) platform. It is completely a novel implementation of an analog FTS in an SDR platform of NI Flex-RIO system. This single platform based design appears as a substitute for the previously used multiple platforms based complex system. Ruggedization and relevance design methods are required for the FTS design. Hence, the blueprint of the FTS is carried out in a field-programmable gate array. It ensures reconfigurable, interoperable operations with precise, reliable, and future upgradable implementation. Efficient optimization methods have been adopted to minimize the use of hardware resources. LabVIEW, a graphical programming language, is used for rapid prototyping. The validation of the system was done both in subsystem level as well as the integrated level at real-time mission scenario.
Autors: Amiya Ranjan Panda;Debahuti Mishra;Hare Krishna Ratha;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2360 - 2368
Publisher: IEEE
 
» FPGA-Based EMD Assist Block for Motion Detection in Critical Environments
Abstract:
This study aims to carry out the implementation in FPGA (Field Programmable Gate Array) of a processing system capable of detecting and tracking moving vehicles without losing the system's reliability and efficiency of real-time application. Hence, for simple technique of tracking reach good results is proposed for removing shadows, an auxiliary processing based on insect vision system EMD (Elementary Motion Detector). The principle of this processing is based on cross-correlation and has been implemented in some work to get the direction of moving objects, however, this work is modified and implemented to auxiliary in removing shadows of objects detected using color, spatial and temporal information. The proposed auxiliary processing proves to be efficient in a video stream where the two most critical vehicles are selected with respect the cast shadow. The results of the implementation proposal are presented in terms of resource consumption and maximum operating frequency in a Spartan-6 FPGA-based development board. The experimental results are obtained in co-simulation system and show the effectiveness of the proposed system.
Autors: Egidio Ieno Junior;Luis Manuel Garces;Tales Cleber Pimenta;Alejandro Jose Cabrera;
Appeared in: IEEE Latin America Transactions
Publication date: Oct 2017, volume: 15, issue:10, pages: 1856 - 1863
Publisher: IEEE
 
» FPGA-Based Scalable and Power-Efficient Fluid Simulation using Floating-Point DSP Blocks
Abstract:
High-performance and low-power computation is required for large-scale fluid dynamics simulation. Due to the inefficient architecture and structure of CPUs and GPUs, they now have a difficulty in improving power efficiency for the target application. Although FPGAs become promising alternatives for power-efficient and high-performance computation due to their new architecture having floating-point (FP) DSP blocks, their relatively narrow memory bandwidth requires an appropriate way to fully exploit the advantage. This paper presents an architecture and design for scalable fluid simulation based on data-flow computing with a state-of-the-art FPGA. To exploit available hardware resources including FP DSPs, we introduce spatial and temporal parallelism to further scale the performance by adding more stream processing elements (SPEs) in an array. Performance modeling and prototype implementation allow us to explore the design space for both the existing Altera Arria10 and the upcoming Intel Stratix10 FPGAs. We demonstrate that Arria10 10AX115 FPGA achieves 519 GFlops at 9.67 GFlops/W only with a stream bandwidth of 9.0 GB/s, which is 97.9 percent of the peak performance of 18 implemented SPEs. We also estimate that Stratix10 FPGA can scale up to 6844 GFlops by combining spatial and temporal parallelism adequately.
Autors: Kentaro Sano;Satoru Yamamoto;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Oct 2017, volume: 28, issue:10, pages: 2823 - 2837
Publisher: IEEE
 
» Fractional-N DPLL-Based Low-Power Clocking Architecture for 1–14 Gb/s Multi-Standard Transmitter
Abstract:
A low-power clocking solution is presented based on fractional-N highly digital LC-phase-locked loop (PLL) and sub-sampled ring PLL targeting multi-standard SerDes applications. The shared fractional-N digital LC-PLL covers 7–10 GHz frequency range consuming only 8-mW power and occupying 0.15 mm2 of silicon area with integrated jitter of 264 fs. Frequency resolution of the LC-PLL is 2 MHz. Per lane clock is generated using wide bandwidth ring PLL covering 800 MHz to 4 GHz to support the data rates between 1 and 14 Gb/s. The ring PLL supports dither-less fractional resolution of 250 MHz, corrects I/Q error with split tuning, and achieves less than 400-fs integrated jitter. Transmitter works at 14 Gb/s with power efficiency of 0.80 pJ/bit.
Autors: Masum Hossain;Waleed El-Halwagy;AKM Delwar Hossain; Aurangozeb;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Oct 2017, volume: 52, issue:10, pages: 2647 - 2662
Publisher: IEEE
 
» Fragmentation-Avoiding Spectrum Assignment Strategy Based on Spectrum Partition for Elastic Optical Networks
Abstract:
A fragmentation-avoiding spectrum assignment strategy based on spectrum partition is proposed, which is used to resolve the spectrum fragmentation problem in elastic optical networks. For alleviating spectrum fragmentation, a spectrum partition policy, splitting the whole optical spectrum into several dedicated partitions, is presented. Based on this, a joint first-last-fit spectrum assignment policy is presented to enhance the probability of successful transmission of request and spectrum efficiency, where each partition is first used to transmit requests with the same rate in the first-fit policy; and other partitions are used to search available spectrum resources in the last-fit policy when there are no available spectrum resources in the dedicated partition. Meanwhile, a partition selection formula is designed to minimize the interference of spectrum resources during the last-fit spectrum assignment. Moreover, a reconfiguration mechanism, moving requests that are not transmitted in their dedicated partition to their dedicated partition, is also studied. The simulation results indicate that the proposed algorithm can reduce the bandwidth blocking probability and improve spectrum efficiency.
Autors: Huan-Lin Liu;Lei Lv;Yong Chen;Chengying Wei;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 13
Publisher: IEEE
 
» Free Side-Channel Cross-Technology Communication in Wireless Networks
Abstract:
Enabling direct communication between wireless technologies immediately brings significant benefits including, but not limited to, cross-technology interference mitigation and context-aware smart operation. To explore the opportunities, we propose FreeBee–a novel cross-technology communication technique for direct unicast as well as cross-technology/channel broadcast among three popular technologies of WiFi, ZigBee, and Bluetooth. The key concept of FreeBee is to modulate symbol messages by shifting the timings of periodic beacon frames already mandatory for diverse wireless standards. This keeps our design generically applicable across technologies and avoids additional bandwidth consumption (i.e., does not incur extra traffic), allowing continuous broadcast to safely reach mobile and/or duty-cycled devices. A new interval multiplexing technique is proposed to enable concurrent broadcasts from multiple senders or boost the transmission rate of a single sender. Theoretical and experimental exploration reveals that FreeBee offers a reliable symbol delivery under a second and supports mobility of 30 mph and low duty-cycle operations of under 5%.
Autors: Song Min Kim;Shigemi Ishida;Shuai Wang;Tian He;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Oct 2017, volume: 25, issue:5, pages: 2974 - 2987
Publisher: IEEE
 
» Free Waves [Editor's Comments]
Abstract:
Presents the introductory editorial for this issue of the publication.
Autors: Mahta Moghaddam;
Appeared in: IEEE Antennas and Propagation Magazine
Publication date: Oct 2017, volume: 59, issue:5, pages: 4 - 4
Publisher: IEEE
 
» Freestanding Micro-Supercapacitor With Interdigital Electrodes for Low-Power Electronic Systems
Abstract:
With the rapid development of miniaturized multi-functional systems, micro-energy-storage devices have drawn increasing attention due to the importance of power supply. In this paper, a novel fabrication for freestanding solid-state micro-supercapacitors (MSCs) has been proposed and developed by combining electrolyte transferring with laser patterning process. Typical freestanding MSC is composed of interdigital carbon nanotube/nanofibers as active material employed by laser patterning process, PVA/H3PO4 as both the solid-state electrolyte and the flexible substrate, and gold layer as the current collector. With the in-planar electrode and electrolyte-substrate layout, the dimension of the MSC could be greatly decreased without excess substrate. Taking advantage of electrospinning nanofibers with large surface area and carbon nanotubes with high conductivity, we optimize the line-width (200 ) of the interdigital finger of the MSC, which exhibits high areal capacitance (15.6 mF/cm2) and excellent cycling stability. With the serial design, the working range of MSC units could be greatly enhanced in wearable devices and low-power electronic systems. Therefore, such flexible MSC is a promising candidate to satisfy the requirements of miniaturized energy systems. [2017-0059]
Autors: Yu Song;Xue-Xian Chen;Jin-Xin Zhang;Xiao-Liang Cheng;Hai-Xia Zhang;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Oct 2017, volume: 26, issue:5, pages: 1055 - 1062
Publisher: IEEE
 
» Frequency Doubling of a Pulsed Wavelength-Agile Erbium-Doped Fiber MOPA for Oxygen A-Band Spectroscopy
Abstract:
We report a pulsed wavelength-agile laser near 765 nm, which was frequency doubled from an erbium-doped fiber amplifier for oxygen A-band spectroscopy. A single frequency distributed feedback laser around 1529.6 nm was employed as the seed. After three stages of amplification, its average power was boosted to 610 mW and was then frequency doubled via a 15-mm-long MgO:PPLN crystal with the highest conversion efficiency of 34%. Thanks to the short crystal length expanding the acceptance bandwidth, a power difference of only 36% for the second harmonic output was achieved within the whole wavelength tuning range benefitting low-noise remote sensing. The measured oxygen transmission spectra using a 0.5-meter-long gas cell with multiple passes were mostly in good agreement with the calculations from HITRAN 2012 database indicating the capability of our laser for oxygen A-band related remote sensing.
Autors: Feng You;Tao Chen;Wei Kong;Hao Liu;Yihua Hu;Rong Shu;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 8
Publisher: IEEE
 
» Frequency Shifts of Spectral Lines Generated by Young's Pinhole Wave Scattering Upon a Quasi-Homogeneous Medium
Abstract:
Frequency shifts of light scattered from either a deterministic or random medium have shown great importance in remote sensing imaging applications, however, such scattering system which combines random scatterer with obstacles has not been specifically discussed so far. To solve this problem, we derive analytical expressions for showing the phenomenon that the Young's pinhole wave scattered from a quasi-homogeneous (QH) medium exhibits the red shift of spectral lines, while the first-order Born approximation is applied to treat the weak scattering between the diffractive wave and the medium. The shifted amount of spectrum is strongly dependent of the scattering angle, correlation length of the medium, and Young's pinhole parameter. Furthermore, we also observe that the red shift of the scattered spectrum converts to the blue shift when the correlation length reaches a certain magnitude. Through numerical simulations, analyses are performed on revealing the effects of Young's pinhole parameter and medium's correlation on the spectral shift and spectral switch of the scattered spectrum.
Autors: Jia Li;Yuechun Shi;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 12
Publisher: IEEE
 
» From Cool Chips to Hot Interconnects
Abstract:
This column briefly introduces the articles and departments in the issue.
Autors: Lieven Eeckhout;
Appeared in: IEEE Micro
Publication date: Oct 2017, volume: 37, issue:5, pages: 4 - 5
Publisher: IEEE
 

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