Electrical and Electronics Engineering publications abstract of: 10-2017 sorted by title, page: 15

» Reprogrammable Redundancy for SRAM-Based Cache $V_{\min }$ Reduction in a 28-nm RISC-V Processor
Abstract:
Reducing the operating voltage of digital systems improves energy efficiency, and the minimum operating voltage of a system () is commonly limited by SRAM bitcells. Common techniques to lower SRAM focus on using circuit-level periphery-assist techniques to prevent bitcell failures at low voltage. Alternatively, this paper proposes architecture-level techniques to allow caches to tolerate significant numbers of failing bitcells at low voltage while maintaining correct operation. The presented processor lowers SRAM-based cache using three architectural techniques–bit bypass, dynamic column redundancy, and line disable–that use low-overhead reprogrammable redundancy (RR) to increase the maximum tolerable bitcell failure rate and decrease the minimum operating voltage in processor caches. In a fabricated 28-nm RISC-V-based processor chip, these RR techniques add 2% area overhead to the cache and reduce the of the 1-MB L2 cache by 25%, resulting in a 49% power reduction.
Autors: Brian Zimmer;Pi-Feng Chiu;Borivoje Nikolić;Krste Asanović;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Oct 2017, volume: 52, issue:10, pages: 2589 - 2600
Publisher: IEEE
 
» Residual-Consensus Driven Linear Matching
Abstract:
Linear matching (LM) is a simple and effective method for solving image matching problems. In many cases, image matching problems are nonlinear due to involvement of the geometric transformations; therefore, an essential step for utilizing linear models for image matching is to linearize the geometric transformation matrices that introduce nonlinear terms into image matching problems. Existing LM methods usually use low-order transformations to artificially initialize a linear model. In this paper, we propose a residual-consensus driven LM algorithm that generalizes existing LM methods by allowing higher order transformations to automatically initialize a linear model. Based on the observation that transformation models generated from inlier subsets exhibit correlated behaviors (termed residual consensus hereafter), we develop a residual-consensus robust estimation algorithm to project the nontrivial linear transformation problem into a much smaller subspace, and thus enable efficient optimizations through linear programming. The experimental results on synthetic and real databases demonstrate the effectiveness and robustness of the proposed algorithm.
Autors: Hao Wang;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Oct 2017, volume: 27, issue:10, pages: 2141 - 2152
Publisher: IEEE
 
» Resilience-Aware Frequency Tuning for Neural-Network-Based Approximate Computing Chips
Abstract:
Unlike conventional ICs, approximate computing chips are less sensitive to hardware errors. This fascinating feature can be utilized to improve the performance of chip design and even change the timing closure procedure of digital circuit design flow. In this paper, we study the potential of resilience-aware circuit clocking scheme, and demonstrate the methodology with advanced neural network (NN)-based accelerator. We propose a novel timing analysis and frequency setting method for NN-based approximate computing circuits based on in-field NN retraining. With the proposed iterative retiming-and-retraining framework, NN-based accelerator can be retrained to operate safely at aggressive operating frequencies compared with the frequency decided purely by statistical timing analysis or Monto Carlo analysis. For nanometer process technology with increasing threats of timing errors induced by process variation, noises, and so on, our retiming-and-retraining method enables higher circuit operating frequency and enables dynamic precision/frequency adjustment for approximate computing circuits. We evaluate the methodology with both the neural and deep learning accelerators in experiments. The experimental results show that timing errors in neural circuits can be effectively tamed for different applications, so that the circuits can operate at higher clocking rates under the specified quality constraint or be dynamically scaled to work at a wide range of frequency states with only minor accuracy losses.
Autors: Ying Wang;Jiachao Deng;Yuntan Fang;Huawei Li;Xiaowei Li;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Oct 2017, volume: 25, issue:10, pages: 2736 - 2748
Publisher: IEEE
 
» Resin Directional Flow and Degree of Cure Sensing Using Chirped Optical Fiber Long Period Gratings
Abstract:
The use of chirped long period gratings (CLPGs) for monitoring the flow, the direction of the flow, and the subsequent cure of an epoxy resin is presented. The asymmetric properties of the CLPG and its sensitivity to refractive index changes were exploited to facilitate the measurement of the direction of the flow. The performances of a continuously chirped LPG (CCLPG) and a step chirped LPG (SCLPG) were compared, with the CCLPG showing improved spatial resolution. The CCLPG and SCLPG were also used to monitor changes in the refractive index of the resin during cure, with the results showing close agreement with measurements undertaken simultaneously using a fiber optic Fresnel refractometer.
Autors: Rebecca Y. N. Wong;Edmon Chehura;Stephen W. James;Ralph P. Tatam;
Appeared in: IEEE Sensors Journal
Publication date: Oct 2017, volume: 17, issue:20, pages: 6605 - 6614
Publisher: IEEE
 
» Resonances of Characteristic Modes for Perfectly Conducting Objects
Abstract:
Resonances, i.e., extrema of the eigenvalues of characteristic modes for closed perfectly conducting objects are investigated. The characteristic modal solutions based on the electric, magnetic, and combined field integral operators (EFIO, MFIO, and CFIO) are studied and compared with analytical solutions for a sphere. All these formulations are found to capture both external (radiating) and internal (cavity) resonances predicted by the analytical expressions. At the internal resonances, the eigenvalues obtained with the EFIO- and MFIO-based approaches are not correct, and the corresponding modes are nonunique. These solutions also exhibit a strong duality between the electric (TM) and magnetic (TE) type modes. A connection is found between the external and internal resonances and the condition numbers of the matrices. The modal expansion of the CFIO-based solution is correct, even though it also experiences the nonuniqueness of the EFIO- and MFIO-based solutions.
Autors: Joni Lappalainen;Pasi Ylä-Oijala;Dimitrios C. Tzarouchis;Ari Sihvola;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5332 - 5339
Publisher: IEEE
 
» Resonant-Based Backstepping Direct Power Control Strategy for DFIG Under Both Balanced and Unbalanced Grid Conditions
Abstract:
This paper proposes a resonant-based backstepping direct power control (BS-DPC) strategy for doubly-fed induction generator (DFIG) under both balanced and unbalanced grid conditions. Proper formulae for the BS-DPC strategy are obtained based on the elaborated analysis of the mathematical model of DFIG. The influence of the unbalanced grid voltage on the normal BS-DPC is analyzed. Furthermore, a resonant-based improved strategy is proposed to achieve different control targets under unbalanced grid condition without the need of decomposition of positive- and negative-sequence components. Comparative experimental studies of the resonant-based BS-DPC and the normal BS-DPC for DFIG are conducted to validate the effectiveness of the proposed strategy under both balanced and unbalanced grid conditions. In addition, the experimental results also prove that the proposed resonant-based BS-DPC can achieve a satisfying transient performance.
Autors: Xiaohe Wang;Dan Sun;Z. Q. Zhu;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4821 - 4830
Publisher: IEEE
 
» Resource Allocation in Non-Orthogonal and Hybrid Multiple Access System With Proportional Rate Constraint
Abstract:
Non-orthogonal multiple access (NOMA), which has attracted a lot of attention recently due to its superior spectral efficiency, could play a vital role in improving the capacity of future networks. In this paper, a resource allocation scheme is developed for a downlink multi-user NOMA system. An optimization problem is formulated to maximize the sum rate under the total power and proportional rate constraints. Due to the complexity of computing the optimal solution, we develop a low complexity sub-optimal solution for a two-user scenario and then extend it to the multi-user case by proposing a user-pairing approach as well as a number of power allocation techniques that facilitate dealing with a large number of users in NOMA system. Simulation results support the effectiveness of the proposed approaches and show the close performance to the optimal one. In addition, we propose a new hybrid multiple access technique that combines the properties of NOMA and the orthogonal frequency division multiple access. Simulation results show that the proposed hybrid method provides better performance than NOMA in terms of the overall achievable sum rate and the coverage probability.
Autors: Ziad Qais Al-Abbasi;Daniel K. C. So;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6309 - 6320
Publisher: IEEE
 
» Restoration-Based Merging of Functional Test Sequences
Abstract:
This paper develops a merging procedure for functional test sequences that achieves test compaction for a pool of functional test sequences by reducing the number of sequences in the pool. The procedure has the following new features: 1) in contrast to existing selection procedures, the merging procedure described in this paper increases the fault coverage of test sequences in the pool, thus enhancing the ability to reduce the number of sequences and 2) in contrast to existing procedures that concatenate or merge test sequences, the procedure described in this paper does not increase the lengths of the sequences it merges. The procedure is based on the concept of restoration of test vectors. In the context of test sequence merging, restoration consists of copying test vectors from a test sequence into a test sequence in order to allow to detect faults that detects. The merging procedure focuses on the removal of one test sequence at a time by restoring test vectors from into other sequences, allowing them to detect the faults that detects. Experimental results for benchmark circuits demonstrate that the procedure reduces the number of sequences in a pool significantly.
Autors: Irith Pomeranz;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Oct 2017, volume: 36, issue:10, pages: 1739 - 1749
Publisher: IEEE
 
» Revealing the Nitridation Effects on GaN Surface by First-Principles Calculation and X-Ray/Ultraviolet Photoemission Spectroscopy
Abstract:
In this paper, we report a systematic study of the nitridation effects on GaN surface by first-principles calculations and X-ray/ultraviolet photoemission spectroscopy (XPS/UPS). According to the calculated electronic structures, two surface bands (i.e., the upper band and the lower band) can be seen within the bandgap for the typical surface configurations that may occur in the experimental condition as a result of surface reconstruction. By the deployment of sufficient nitridation, the energy positions of the lower band are modified toward the valence band by ~1 eV, resulting in the overlapping of the lower surface band with the valence band. Meanwhile, the upper surface band is also modified toward the valence band, but by a smaller amount. The modification to the positions of the surface bands is furthermore manifested by XPS/UPS spectra characterization performed on GaN sample that underwent surface treatment with low-energy remote N2 plasma. The theoretical and experimental results insightfully proclaim the nitridation effects on material properties at atomic level, and support a surface-state ionization model for the GaN band-edge (3.4 eV) emission in metal-AlGaN/GaN Schottky-on-heterojunction diode under forward bias.
Autors: Zhaofu Zhang;Baikui Li;Qingkai Qian;Xi Tang;Mengyuan Hua;Baoling Huang;Kevin J. Chen;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4036 - 4043
Publisher: IEEE
 
» Review of Fast Calculation Techniques for Computer-Generated Holograms With the Point-Light-Source-Based Model
Abstract:
Computer-generated holograms (CGHs) are a key technology in electroholography systems; however, heavy calculations are required to calculate CGHs. We review fast calculation techniques for CGH calculation of a point-light-source-based model, which is a simple and general model of a three-dimensional object in an electroholography system. To reduce the calculation time, many methods that reduce the temporal and spatial redundancy of the CGH calculation have been developed (e.g., look-up table method, the wavefront recording plane method, and other approximation techniques). The implementation of such methods on parallel computers (e.g., graphic processing unit and field programmable gate arrays) has also been reported.
Autors: Takashi Nishitsuji;Tomoyoshi Shimobaba;Takashi Kakue;Tomoyoshi Ito;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2447 - 2454
Publisher: IEEE
 
» Review of Silicon Carbide Power Devices and Their Applications
Abstract:
Silicon carbide (SiC) power devices have been investigated extensively in the past two decades, and there are many devices commercially available now. Owing to the intrinsic material advantages of SiC over silicon (Si), SiC power devices can operate at higher voltage, higher switching frequency, and higher temperature. This paper reviews the technology progress of SiC power devices and their emerging applications. The design challenges and future trends are summarized at the end of the paper.
Autors: Xu She;Alex Q. Huang;Óscar Lucía;Burak Ozpineci;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8193 - 8205
Publisher: IEEE
 
» RF Behavior of a 220/251.5-GHz, 2-MW, Triangular Corrugated Coaxial Cavity Gyrotron
Abstract:
In this paper, RF behavior studies of a dual regime coaxial cavity gyrotron designed for electron cyclotron resonance heating and current drive of magnetically confined plasmas in the future fusion reactors are presented. Considering all the design constraints, the mode pair is chosen as and for operation at 220 and 251.5 GHz, respectively. The interaction circuit is initially designed through the cold cavity design. A triangular corrugated insert offers good mode selection and also reduces the localized heating problem. Single mode computations are carried out to optimize the beam parameters for the maximum efficiency of the chosen mode pair. Time-dependent multimode simulations are carried out to conform the power in the desired mode pair and the possibility of power in the competing modes. Start-up analyses are performed before and after space-charge neutralization with nonuniform magnetic field using nominal electron beam parameters obtained from magnetron injection gun calculations. These studies ensure that the continuous wave operation of a coaxial cavity gyrotron is possible with the output power of ≈2 MW with the chosen mode pair.
Autors: S. Yuvaraj;M. V. Kartikeyan;M. K. Thumm;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4287 - 4294
Publisher: IEEE
 
» RF Performance of In Situ SiNx Gate Dielectric AlGaN/GaN MISHEMT on 6-in Silicon-on-Insulator Substrate
Abstract:
A high power-added efficiency and low dynamic on-resistance ( AlGaN/GaN metal–insulator–semiconductor high-electron mobility transistor (MISHEMT) with in situ SiNx insulator design was demonstrated on 150-mm silicon-on-insulator (SOI) substrate. Compared to traditional high-resistivity Si substrate, SiNx/AlGaN/GaN MISHEMT grown on the SOI 5--thick Si active layer performed better tensile stress relaxation and surface flatness. Based on Hall measurement results, electron mobility and the sheet charge density on SOI substrate were improved simultaneously owing to a lower-defect density which is also proofed by pulse measurement and low-frequency noise measurement. Due to the low-feedback substrate capacitance, the bandwidth, and the linearity were also improved simultaneously by SOI substrate design.
Autors: Hsien-Chin Chiu;Hou-Yu Wang;Li-Yi Peng;Hsiang-Chun Wang;Hsuan-Ling Kao;Chih-Wei Hu;Rong Xuan;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4065 - 4070
Publisher: IEEE
 
» RF-MEMS-Based Bandpass-to-Bandstop Switchable Single- and Dual-Band Filters With Variable FBW and Reconfigurable Selectivity
Abstract:
Bandpass (BP)-to-bandstop (BS) switchable filters using radio frequency microelectromechanical system switch are presented here. The filters are implemented in both single- and dual-band versions with variable fractional bandwidth (FBW). Tuning of transmission zeros (TZs) and transmission poles (TPs) for BP filter (BPF) and BS filter (BSF), respectively, is achieved in both single- and dual-band cases leading to reconfigurable selectivity. The first odd-mode frequency of the filter is suppressed using a fixed capacitor and the second odd mode is brought closer to the first even-mode with another variable capacitor to form the passband(s). The second capacitor tunes both the second odd mode and TZs (for BPF) or TPs (for BSF) minimizing the requirement of any extra tuning element. In a single-band fabricated BPF, tuning second odd mode gives the FBW variation of 9.3%–72.7% with TZ on the lower side and 5.6%–55.6% with TZ on the higher side of the passband. The 15-dB FBW of a single-band BSF having TP on both sides of the stopband varies over 5.2%–20.7%. The two passbands of a dual-band BPF independently vary over 4.5%–24% and 4.5%–13%. Also, the 15-dB FBW of the first and second stopbands of BSF independently varies over 6.5%–13.2% and 1.5%–3.6%, respectively.
Autors: Nagendra Kumar;Yatendra Kumar Singh;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Oct 2017, volume: 65, issue:10, pages: 3824 - 3837
Publisher: IEEE
 
» Rise-Time Improvement in Bipolar Pulse Solid-State Marx Modulators
Abstract:
This paper presents the effect of stray capacitances in bipolar (negative and/or positive) pulses generated by the two different topologies of the solid-state Marx modulators. According to the analysis, the stray capacitances influence the energy transfer from the Marx modulator capacitors to the load affecting the bipolar (negative and/or positive) pulse rise time. This paper deals with the structure design to reduce the influence of the stray capacitance and to improve the pulse rise time of these bipolar solid-state Marx modulators. A four-stage laboratory prototype of the two topologies has been assembled using 1200-V insulated gate bipolar transistors and diodes, operating with 1000-V dc input voltage and 1-kHz frequency, producing 4-kV bipolar pulses, with 5- pulse duration and 120-ns rise time, into a resistive load.
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: 2656 - 2660
Publisher: IEEE
 
» Risk-Averse Energy Trading in Multienergy Microgrids: A Two-Stage Stochastic Game Approach
Abstract:
Multienergy microgrids are a promising solution to improve overall energy (electricity, cooling, heating, etc.) efficiency. In this paper, a new optimal energy trading strategy is developed considering the risk from uncertain energy supply and demand in a set of individual multienergy microgrids. According to the historical data about energy supply of each microgrid, an aggregator aims to maximize each microgrid's profit while minimizing the risk of overbidding for renewable energy resources trading based microgrids. A novel two-stage stochastic game model with Cournot Nash pricing mechanism and the conditional value-at-risk criterion is proposed to characterize the payoff function of each microgrid. The sample average approximation (SAA) technique is employed to approximate the stochastic Nash equilibrium of the game model. The existence of the SAA Nash equilibrium is investigated and the corresponding Nash equilibrium seeking algorithm is also realized in a distributed manner. The proposed method is validated by numerical simulations on real-world data collected in Australia, and the results show that the SAA Nash equilibrium based strategy can effectively reduce the risk of not meeting the demand and improve the economic benefits for each microgrid.
Autors: Chaojie Li;Yan Xu;Xinghuo Yu;Caspar Ryan;Tingwen Huang;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2620 - 2630
Publisher: IEEE
 
» Roadside Unit Caching: Auction-Based Storage Allocation for Multiple Content Providers
Abstract:
Recent improvements in vehicular ad hoc networks are accelerating the realization of intelligent transportation system (ITS), which not only provides road safety and driving efficiency, but also enables infotainment services. Since data dissemination plays an important part in ITS, recent studies have found caching as a promising way to promote the efficiency of data dissemination against rapid variation of network topology. In this paper, we focus on the scenario of roadside unit (RSU) caching, where multiple content providers (CPs) aim to improve the data dissemination of their own contents by utilizing the storages of RSUs. To deal with the competition among multiple CPs for limited caching facilities, we propose a multi-object auction-based solution, which is sub-optimal and efficient to be carried out. A caching-specific handoff decision mechanism is also adopted to take advantages of the overlap of RSUs. Simulation results show that our solution leads to a satisfactory outcome.
Autors: Zhiwen Hu;Zijie Zheng;Tao Wang;Lingyang Song;Xiaoming Li;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6321 - 6334
Publisher: IEEE
 
» Robotic Through-Wall Imaging: Radio-Frequency Imaging Possibilities with Unmanned Vehicles.
Abstract:
Using electromagnetic waves for sensing has been of interest to the research community for many years. More recently, sensing with lower frequencies, such as with radio waves and even with Wi-Fi, has become of interest due to factors like safety and availability of the transceivers. In particular, there has been a considerable interest in using radio-frequency (RF) signals to sense and obtain information about the environment in various contexts, such as imaging, localization, tracking, and occupancy estimation [1]-[10]. See-through imaging (also known as through-wall imaging) has, in particular, been of considerable interest to the research community. The ability to see through occluded objects can be beneficial to many applications, such as search and rescue, surveillance and security, archaeological discovery, detection/classification of occluded objects, and medical applications. Despite great interest in this area, however, see-through imaging is still a considerably challenging problem, especially with everyday RF signals.
Autors: Saandeep Depatla;Chitra R. Karanam;Yasamin Mostofi;
Appeared in: IEEE Antennas and Propagation Magazine
Publication date: Oct 2017, volume: 59, issue:5, pages: 47 - 60
Publisher: IEEE
 
» Robust 2-D–3-D Registration Optimization for Motion Compensation During 3-D TRUS-Guided Biopsy Using Learned Prostate Motion Data
Abstract:
In magnetic resonance (MR)-targeted, 3-D transrectal ultrasound (TRUS)-guided biopsy, prostate motion during the procedure increases the needle targeting error and limits the ability to accurately sample MR-suspicious tumor volumes. The robustness of the 2-D–3-D registration methods for prostate motion compensation is impacted by local optima in the search space. In this paper, we analyzed the prostate motion characteristics and investigated methods to incorporate such knowledge into the registration optimization framework to improve robustness against local optima. Rigid motion of the prostate was analyzed adopting a mixture-of-Gaussian (MoG) model using 3-D TRUS images acquired at bilateral sextant probe positions with a mechanically assisted biopsy system. The learned motion characteristics were incorporated into Powell’s direction set method by devising multiple initial search positions and initial search directions. Experiments were performed on data sets acquired during clinical biopsy procedures, and registration error was evaluated using target registration error (TRE) and converged image similarity metric values after optimization. After incorporating the learned initialization positions and directions in Powell’s method, 2-D–3-D registration to compensate for motion during prostate biopsy was performed with rms ± std TRE of 2.33 ± 1.09 mm with ~3 s mean execution time per registration. This was an improvement over 3.12 ± 1.70 mm observed in Powell’s standard approach. For the data acquired under clinical protocols, the converged image similarity metric value improved in ≥8% of the registrations whereas it degraded only ≤1% of the registrations. The reported improvements in optimization indicate useful advancement- in robustness to ensure smooth clinical integration of a registration solution for motion compensation that facilitates accurate sampling of the smallest clinically significant tumors.
Autors: Tharindu De Silva;Derek W. Cool;Jing Yuan;Cesare Romagnoli;Jagath Samarabandu;Aaron Fenster;Aaron D. Ward;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Oct 2017, volume: 36, issue:10, pages: 2010 - 2020
Publisher: IEEE
 
» Robust Adaptive Control for Dynamic Positioning of Ships
Abstract:
In this paper, a robust adaptive control scheme with the global asymptotic stability with respect to positioning errors is proposed for dynamic positioning (DP) of ships in the presence of time-varying unknown bounded environmental disturbances. The unknown environmental disturbances are expressed as the outputs of a linear exosystem with unknown parameters and all eigenvalues of system matrix lying on the imaginary axis. On the basis of this exosystem, the disturbances are further represented as the outputs of a linear model of canonical form with unknown disturbances being inputs by a multivariate linear regression model whose regressor is the state vector of the linear model and whose regression parameters depend on unknown parameters of the linear exosystem. This representation allows us to construct an observer to estimate the unavailable state vector (regressor) in the linear model and hence convert the disturbance compensation control for the DP of ships to an adaptive control problem. Then, a robust adaptive control law for the DP of ships is designed incorporating the constructed observer and the projection algorithm into the vectorial backstepping method. The global asymptotic stability with respect to positioning errors of the DP closed-loop control system is proved applying Lyapunov stability theory and Barbalat's lemma. Finally, simulation results on a supply ship Northern Clipper in two different disturbance cases and simulation comparisons with an existing DP adaptive robust control scheme demonstrate more effectiveness and less conservativeness of our proposed control scheme.
Autors: Xin Hu;Jialu Du;Yuqing Sun;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Oct 2017, volume: 42, issue:4, pages: 826 - 835
Publisher: IEEE
 
» Robust Adaptive State Constraint Control for Uncertain Switched High-Order Nonlinear Systems
Abstract:
Under the weaker conditions on system power and nonlinear functions, this paper focuses on the robust adaptive state constraint control for a class of uncertain switched high-order nonlinear systems. With the help of p-times differentiable unbounded function, a robust adaptive state-feedback controller is designed by combining the homogeneous domination approach with parameter separation principle. When the initial condition satisfies a suitable requirement, it is shown that all signals of the closed-loop system are bounded and system state is within a prespecified limit range by the proposed controller. As a practical application, the design scheme is utilized to the continuous stirred tank reactor with two modes feed stream. To further demonstrate the efficiency of the proposed controller, another numerical example is given.
Autors: Liang Liu;Xuebo Yang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8108 - 8117
Publisher: IEEE
 
» Robust Constrained Attitude Control of Spacecraft Formation Flying in the Presence of Disturbances
Abstract:
In this paper, the robust control problem for spacecraft formation flying in virtual structure algorithm is addressed. The effects of external disturbances, model uncertainties, sensor noises, and actuator saturation are taken into account. A robust controller based on μ-synthesis is first designed to overcome the environmental disturbances. To obtain a control law with lower order, an H-based linear matrix inequality controller is designed, using the linearized model with uncertainties. Then, a robust adaptive controller, based on the Lyapunov stability theorem, is presented to overcome a broader range of model uncertainties, which also guarantees the stability. From a comparison viewpoint, the numerical results are also demonstrated to show the performance of the robust controllers in tracking the desired attitude and position.
Autors: Bahare Shahbazi;Maryam Malekzadeh;Hamid Reza Koofigar;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Oct 2017, volume: 53, issue:5, pages: 2534 - 2543
Publisher: IEEE
 
» Robust Deadlock Avoidance for Sequential Resource Allocation Systems With Resource Outages
Abstract:
While the supervisory control (SC) problem of (maximally permissive) deadlock avoidance for sequential resource allocation systems (RASs) has been extensively studied in the literature, the corresponding results that are able to address potential resource outages are quite limited, both, in terms of their volume and their control capability. This paper leverages the recently developed SC theory for switched discrete event systems (s-DES) in order to provide a novel systematic treatment of this more complicated version of the RAS deadlock avoidance problem. Following the modeling paradigm of s-DES, both the operation of the considered RAS and the corresponding maximally permissive SC policy are decomposed over a number of operational modes that are defined by the running sets of the failing resources. In particular, the target supervisor must be decomposed to a set of “localized predicates,” where each predicate is associated with one of the operational modes. A significant part, and a primary contribution, of this paper concerns the development of these localized predicates that will enable the formal characterization and the effective computation of the sought supervisor. With these predicates available, a distributed representation for the sought supervisor that is appropriate for real-time implementation is eventually obtained through an adaptation of the relevant distributed algorithm that is provided by the current s-DES SC theory. Note to Practitioners—This paper extends the existing theory of deadlock avoidance for buffer-space allocation in flexibly automated production systems so that it accounts for disruptive effects due to potential temporary outages of some of the system servers. The set of the failing servers at any time instant defines the corresponding operational mode for the underlying resource allocation system. The primary problem that is addressed by this paper is the syn- hesis of a resource allocation policy that will ensure the ability of all process instances that do not require the failing resources in a particular mode, to execute repetitively and complete successfully while the system remains in that mode. In line with some past literature on this problem, we call the corresponding supervisory control problem as “robust deadlock avoidance,” and we leverage results from the recently emerged theory for modeling and control of switched discrete event systems in order to characterize and compute a maximally permissive solution for it.
Autors: Spyros Reveliotis;Zhennan Fei;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Oct 2017, volume: 14, issue:4, pages: 1695 - 1711
Publisher: IEEE
 
» Robust Estimation of Sparse Narrowband Spectra from Neuronal Spiking Data
Abstract:
Objective: Characterizing the spectral properties of neuronal responses is an important problem in computational neuroscience, as it provides insight into the spectral organization of the underlying functional neural processes. Although spectral analysis techniques are widely used in the analysis of noninvasive neural recordings such as EEG, their application to spiking data is limited due to the binary and nonlinear nature of neuronal spiking. In this paper, we address the problem of estimating the power spectral density of the neural covariate driving the spiking statistics of a neuronal population from binary observations. Methods: We consider a neuronal ensemble spiking according to Bernoulli statistics, for which the conditional intensity function is given by the logistic map of a harmonic second-order stationary process with sparse narrowband spectra. By employing sparsity-promoting priors, we compute the maximum a posteriori estimate of the power spectral density of the process from the binary spiking observations. Furthermore, we construct confidence intervals for these estimates by an efficient posterior sampling procedure. Results: We provide simulation studies which reveal that our method outperforms the existing methods for extracting the frequency content of spiking data. Application of our method to clinically recorded spiking data from a patient under general anesthesia reveals a striking resemblance between our estimated power spectral density and that of the local field potential signal. This result corroborates existing findings regarding the salient role of the local field potential as a major neural covariate of rhythmic cortical spiking activity under anesthesia. Conclusion: Our technique allows us to analyze the harmonic structure of spiking activity in a robust fashion, independently of the local field potentials, and without any prior assumption of the spect- al spread and content of the underlying neural processes. Significance: Other than its usage in the spectral analysis of neuronal spiking data, our technique can be applied to a wide variety of binary data, such as heart beat data, in order to obtain a robust spectral representation.
Autors: Sina Miran;Patrick L. Purdon;Emery N. Brown;Behtash Babadi;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Oct 2017, volume: 64, issue:10, pages: 2462 - 2474
Publisher: IEEE
 
» Robust Finite-Time Control for Autonomous Operation of an Inverter-Based Microgrid
Abstract:
Recently, more and more small-scale renewable generation sources based distributed generators are integrated to the existing power network through power electronic-based converters. Microgrid has been proposed as a solution to meet the challenges posed by highly intermittent renewable generations. To address the fast response and complex operating conditions of various inverters in an autonomous microgrid, this paper proposes a robust finite-time control algorithm for frequency/voltage regulation and active/reactive power control. The major advantages of the proposed control algorithm include, being robust and stable against various load disturbances, unmodeled dynamics and system parameter perturbations; enabling flexible convergence time according to user preferences and different operating conditions' requirements. The finite-time convergence of the robust control algorithm is guaranteed through rigorous analysis and the balance between control accuracy and chattering suppression is investigated. Simulation results demonstrate the effectiveness of the proposed robust finite-time control algorithm.
Autors: Yinliang Xu;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2717 - 2725
Publisher: IEEE
 
» Robust High Resolution Time of Arrival Estimation for Indoor WLAN Ranging
Abstract:
This paper proposes a novel robust high resolution time of arrival (TOA) estimation method for IEEE 802.11g/n range estimation in indoor environments. The algorithm identifies the TOA of ranging symbols by means of baseband signal processing using a single 802.11 channel. A subsample signal model provides high timing resolution. The CLEAN deconvolution algorithm, coupled with a parameter optimization step, provides robustness to multipath. Two ranging symbols are investigated: the 802.11 standard long training sequence and an impulsive symbol. In real-world wireless line of sight experiments, at ranges of up to 25 m, the method when applied to impulsive symbols was found to provide median ranging errors of 0.34 and 0.93 m with directional and omnidirectional antennas, respectively.
Autors: Ahmed Makki;Abubakr Siddig;Chris J. Bleakley;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Oct 2017, volume: 66, issue:10, pages: 2703 - 2710
Publisher: IEEE
 
» Robust Intensity-Based Localization Method for Autonomous Driving on Snow–Wet Road Surface
Abstract:
Autonomous vehicles are being developed rapidly in recent years. In advance implementation stages, many particular problems must be solved to bring this technology into the market place. This paper focuses on the problem of driving in snow and wet road surface environments. First, the quality of laser imaging detection and ranging (LIDAR) reflectivity decreases on wet road surfaces. Therefore, an accumulation strategy is designed to increase the density of online LIDAR images. In order to enhance the texture of the accumulated images, principal component analysis is used to understand the geometrical structures and texture patterns in the map images. The LIDAR images are then reconstructed using the leading principal components with respect to the variance distribution accounted by each eigenvector. Second, the appearance of snow lines deforms the expected road context in LIDAR images. Accordingly, the edge profiles of the LIDAR and map images are extracted to encode the lane lines and roadside edges. Edge matching between the two profiles is then calculated to improve localization in the lateral direction. The proposed method has been tested and evaluated using real data that are collected during the winter of 2016–2017 in Suzu and Kanazawa, Japan. The experimental results show that the proposed method increases the robustness of autonomous driving on wet road surfaces, provides a stable performance in laterally localizing the vehicle in the presence of snow lines, and significantly reduces the overall localization error at a speed of 60 km/h.
Autors: Mohammad Aldibaja;Naoki Suganuma;Keisuke Yoneda;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2369 - 2378
Publisher: IEEE
 
» Robust LFM Target Detection in Wideband Sonar Systems
Abstract:
Linear frequency modulation (LFM) signals have been widely used for target detection in active sonar systems due to their robustness to reverberation. However, LFM active sonar requires a large number of reference signals for detecting targets moving with unknown speeds. To obtain more accurate detection results, more reference signals are required, resulting in an increased computational burden and memory size. To cope up with this problem, we propose a new fast target detection method that is robust to the variation of unknown target speed. A large number of reference signals come into a single reference signal by aligning them with precalculated time-shifts, which is followed by a summation process. Both narrowband and wideband cases are considered. The proposed method secures a signal-to-noise ratio (SNR), approaching that of the optimal matched filter output, that is also robust to the variation of target speed and thus it is very useful for the practical use in antitorpedo torpedoes or supercavitating underwater missiles that need to equip low-complexity and robust signal processing systems. Moreover, a rough Doppler estimation is presented using the proposed replica design method. Performance analyses show that the proposed method provides output SNR close to the optimal performance and that the computational load is extremely reduced as compared to the conventional LFM target detection method.
Autors: Dong-Hun Lee;Jong-Woo Shin;Dae-Won Do;Sang-Moon Choi;Hyoung-Nam Kim;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Oct 2017, volume: 53, issue:5, pages: 2399 - 2412
Publisher: IEEE
 
» Robust Model Predictive Controller for Tracking Changing Periodic Signals
Abstract:
In this paper, we propose a novel robust model predictive controller for tracking periodic signals for linear systems subject to bounded additive uncertainties based on nominal predictions and constraint tightening. The proposed controller joins optimal periodic trajectory planning and robust control for tracking in a single optimization problem and guarantees that the perturbed closed-loop system converges asymptotically to a neighborhood of an optimal reachable periodic trajectory while robustly satisfying the constraints. In addition, the closed-loop system maintains recursive feasibility even in the presence of sudden changes in the target reference.
Autors: M. Pereira;D. Muñoz de la Peña;D. Limon;I. Alvarado;T. Alamo;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5343 - 5350
Publisher: IEEE
 
» Robust Noncooperative Spectrum Sharing Game in Underwater Acoustic Interference Channels
Abstract:
This paper focuses on underwater acoustic (UA) communications and proposes a decentralized spectrum sharing method for noncooperative orthogonal frequency-division multiplexing systems in interference channels. The problem is formulated as a noncooperative game where the players are UA communication systems aiming at finding the power allocation on subcarriers that maximizes a utility function related to their information rate. Realistic assumptions regarding the UA context are formulated. Frequency-selective and randomly time-varying channels are considered. Each system is constrained in average power and adapts its power allocation strategy only with local knowledge of its channel statistics and noise plus interference power spectral density. This knowledge is obtained through a feedback link from the receiver. Estimation errors on the channel statistics are taken into account, thanks to a robust reformulation of the game. We show that an efficient decentralized spectrum sharing can be achieved when all players use a water-filling strategy against each other iteratively. Simulations results are obtained on synthetic but realistic channels. In configurations where the UA communication systems are in close areas, significant increases of spectral efficiencies can be expected compared to the conventional uniform power allocation. Results on channels sounded at sea support our conclusions.
Autors: Antony Pottier;François-Xavier Socheleau;Christophe Laot;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Oct 2017, volume: 42, issue:4, pages: 1019 - 1034
Publisher: IEEE
 
» Robust Pose Estimation for Multirotor UAVs Using Off-Board Monocular Vision
Abstract:
This paper deals with the problem of pose estimation (or motion estimation) for multirotor unmanned aerial vehicles (UAVs) by using only an off-board camera. An extended Kalman filter (EKF) is often adopted to solve this problem. However, the accuracy and robustness of an EKF are limited partly by the usage of an existing linear constant-velocity process model applicable to many rigid objects. For such a reason, a nonlinear constant-velocity process model featured with the characteristics of multirotor UAVs is proposed in this paper, the superiority of which is explained from the perspective of observability. With the new process model and a generic camera model, a practical EKF method suitable for conventional cameras and fish-eye cameras is then proposed. By taking EKF implementation into account, a general correspondence method that could handle any number of feature points is further designed. Simulation and real experiments show that the proposed EKF method is more robust against noise and occlusion than currently employed filtering methods.
Autors: Qiang Fu;Quan Quan;Kai-Yuan Cai;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 7942 - 7951
Publisher: IEEE
 
» Robust Resource Allocation in Full-Duplex-Enabled OFDMA Femtocell Networks
Abstract:
In this paper, we study resource allocation for full-duplex communications in an orthogonal frequency division multiple access femtocell network. We aim to maximize the throughput of the femtocell while avoiding severe inter-tier interference to the macrocell via joint sub-channel assignment and power allocation. To be more practical, we take channel estimation error into account and use the robust optimization theory to model the uncertainty in interference channels. By using the Lagrangian dual method, we decompose the original optimization problem into a primal problem and a dual problem. We adopt the concave-convex procedure to transform the non-convex primal problem into a tractable form through sequential convex approximations and then utilize the sub-gradient method to solve the dual problem. Simulation results show the effectiveness of the proposed algorithm and demonstrate the impact of channel uncertainty on the system performance.
Autors: Sa Xiao;Xiangwei Zhou;Yi Yuan-Wu;Geoffrey Ye Li;Wei Guo;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6382 - 6394
Publisher: IEEE
 
» Robust Sonar ATR Through Bayesian Pose-Corrected Sparse Classification
Abstract:
Sonar imaging has seen vast improvements over the last few decades due in part to advances in synthetic aperture sonar. Sophisticated classification techniques can now be used in sonar automatic target recognition (ATR) to locate mines and other threatening objects. Among the most promising of these methods is sparse reconstruction-based classification (SRC), which has shown an impressive resiliency to noise, blur, and occlusion. We present a coherent strategy for expanding upon SRC for sonar ATR that retains SRC’s robustness while also being able to handle targets with diverse geometric arrangements, bothersome Rayleigh noise, and unavoidable background clutter. Our method, pose-corrected sparsity (PCS), incorporates a novel interpretation of a spike and slab probability distribution toward use as a Bayesian prior for class-specific discrimination in combination with a dictionary learning scheme for localized patch extractions. Additionally, PCS offers the potential for anomaly detection in order to avoid false identifications of tested objects from outside the training set with no additional training required. Compelling results are shown using a database provided by the U.S. Naval Surface Warfare Center.
Autors: John McKay;Vishal Monga;Raghu G. Raj;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5563 - 5576
Publisher: IEEE
 
» Robust Spatiotemporal LS-SVM Modeling for Nonlinear Distributed Parameter System With Disturbance
Abstract:
Most distributed parameter systems (DPS) have a strongly nonlinear spatiotemporal nature and are affected by disturbance. However, most of the existing DPS modeling methods only consider the linear relation between the spatial positions, but neglect the nonlinear one. Additionally, they also do not account for the influence of disturbance. Thus, in this paper, a robust spatiotemporal least squares support vector machine (LS-SVM) modeling method for DPS with disturbance is proposed. First, a spatial kernel function is constructed in order to describe the nonlinear relation between spatial positions. An optimal fusion method is then developed to derive a robust temporal coefficient, from which the influence of disturbance can be rejected. Through the integration of the spatial kernel function and the robust temporal coefficient, a robust spatiotemporal LS-SVM model is constructed. Since this modeling not only considers the nonlinear nature but also takes the influence of disturbance into account, it has the ability to adapt well to the nonlinear spatiotemporal dynamics, even when disturbance is presented. The analysis and proof show that the proposed robust spatiotemporal LS-SVM modeling method has the better robust performance as compared to the existing ones. Case studies not only demonstrate the effectiveness of the proposed method, but also demonstrate its superior robustness than other conventional modeling methods.
Autors: Xinjiang Lu;Wei Zou;Minghui Huang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8003 - 8012
Publisher: IEEE
 
» Robust Visual Tracking via Collaborative Motion and Appearance Model
Abstract:
In this paper, robust visual tracking scheme is achieved through a novel sparse tracking via collaborative motion and appearance (TCMA). A coarse-to-fine framework with both motion and holistic appearance information is taken into consideration. In coarse search, we employ an optical flow map for the generation of motion particles. A rough estimation of target image patch is obtained using -regularized least square method in coarse search stage. In fine search, a novel smooth term is proposed in the cost function to improve the robustness of the tracker. With this smooth term, the object appearance in the previous frame will also affect the calculation of sparse coefficient in the current frame. It allows the tracker involving temporal information between consecutive frames instead of only considering single frame appearance information as in the conventional sparse coding-based tracking algorithms. In order to reserve the original and latest appearance information simultaneously in the template, a quadratic-function-like weight allocation scheme combining with particle contributed histogrammic correlation is developed in the updating stage. Both qualitative and quantitative studies are conducted on a set of challenging image sequences. The superior performance over other state-of-the-art algorithms is verified through the experiment.
Autors: Fangwen Tu;Shuzhi Sam Ge;Yazhe Tang;Chang Chieh Hang;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2251 - 2259
Publisher: IEEE
 
» Robust Weighted Least Squares Method for TOA-Based Localization Under Mixed LOS/NLOS Conditions
Abstract:
In this letter, the time-of-arrival-based localization problem under mixed line-of-sight/non-line-of-sight conditions is addressed. Based on the a priori information of known path status, we propose a new robust weighted least squares (RWLS) method to improve the performance of the existing RWLS method, and the weights in the new RWLS problem are derived and explicitly given. The proposed RWLS problem is approximately solved by employing the second-order cone relaxation technique. Furthermore, when the path status is incorrectly identified, we propose a procedure of correcting the incorrect path status to make the RWLS method robust against the path status identification errors. The performance of the new RWLS method is verified by computer simulations.
Autors: Wei Wang;Gang Wang;Jie Zhang;Youming Li;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2226 - 2229
Publisher: IEEE
 
» Rotary Joint Perpendicularly Fed by a Substrate Integrated Waveguide Feeder
Abstract:
Two rotary joints perpendicularly fed by the substrate integrated waveguide (SIW) feeder are presented in this paper. The planar SIW feeder excites the circular waveguide with the desired rotational symmetric mode through a circular slot, whose effect can be modeled through a horizontal magnetic current on the top surface of the SIW. First, a single-layer SIW feeder is designed in the rotary joint with simple configuration. After that, a dual-layer SIW feeder is proposed to improve the performance of the single-layer version, especially for the bandwidth. Both of them have two controllable transmission poles, which can be used to optimize performance. After introducing the design principle and process, two rotary joints perpendicularly fed by different SIW feeders are fabricated and measured. For the dual-layer feeder rotary joint, it is able to operate from 11.1 to 12.4 GHz. Within an 11.1% relative bandwidth, its insertion loss is less than 1.21 dB and return loss is better than 10.85 dB when being rotated at different angles.
Autors: Zhi Jie Xuan;Yu Jian Cheng;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Oct 2017, volume: 65, issue:10, pages: 3761 - 3768
Publisher: IEEE
 
» Rotational Energy Harvesting To Prolong Flight Duration of Quadcopters
Abstract:
This paper presents a rotational energy harvester using a brushless dc (BLdc) generator to harvest ambient energy for quadcopter in order to prolong it flight duration. For a quadcopter, its endurance is essential in order to achieve operational goals such as scientific research, security, surveillance, and reconnaissance. Because quadcopters have a limitation on size and mass, they cannot carry a large mass of on-board energy thereby having short flight time. In this paper, BLdc generators are coupled with the propellers of the quadcopter to transfer kinetic energy from the propellers to the generator. Taking into consideration the power requirement of quadcopter, the output of the generator is amplified using dc–dc boost, and is regulated to power and charge the on-board battery. The BLdc generator is simulated in MATLAB/Simulink. A final prototype of the rotational energy harvesting system is built, and this comprises a quadcopter, power management system, and a battery charging system.
Autors: Robert A. Sowah;Moses Amoasi Acquah;Abdul R. Ofoli;Godfrey A. Mills;Koudjo M. Koumadi;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4965 - 4972
Publisher: IEEE
 
» SAR Ground Plane Mover Signatures for Nonzero Radar Ascent
Abstract:
Recent spotlight synthetic aperture radar analyses predict the two-dimensional range migration signature smears induced by targets with arbitrary motion in the ground plane. These investigations were limited to a constant-velocity radar motion with level flight path. The current correspondence removes this constraint by including the radar trajectory ascent angle.
Autors: David Alan Garren;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Oct 2017, volume: 53, issue:5, pages: 2214 - 2220
Publisher: IEEE
 
» Saturated Adaptive Control of an Electrohydraulic Actuator with Parametric Uncertainty and Load Disturbance
Abstract:
In this paper, a saturated adaptive control of an electrohydraulic actuator is proposed to drive the joint motion of a two-degree-of-freedom robotic arm. Due to the largely unknown load disturbance from the driven force/torque of the robotic arm and the existing control saturation of a servo valve, a Nussbaum function is designed to compromise between the antiwindup control effect and the dynamic response performance of an electrohydraulic system. Then, an adaptive parametric estimation law is designed to estimate the hydraulic parametric uncertainties. The effectiveness of the proposed controller has been demonstrated by comparative experimental study, which indicates that this controller can quickly recover the unsaturated dynamics with satisfactory tracking accuracy under largely unknown load disturbance and parametric uncertainty.
Autors: Qing Guo;Jingmin Yin;Tian Yu;Dan Jiang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 7930 - 7941
Publisher: IEEE
 
» Scalable Fabrication of PEGDA Microneedles Using UV Exposure via a Rotating Prism
Abstract:
We propose a simple, fast, height-scalable, and direct way to fabricate highly biocompatible polyethylene glycol diacrylate (PEGDA) microneedles. A needle-shaped distribution of ultraviolet (UV) exposure dose is formed in PEGDA by applying UV light through a rotating prism. A prism makes UV light rays bend, such that the base angle of the prism determines the inclined angle of the light. Thus, the microneedle height can be controlled by varying the base angles of the prism. We experimentally demonstrate the direct height-scalable potential. The microneedle height decreases and the microneedle tip angle increases with increases in the base angle of the prism. These results indicate that the microneedle geometry can be easily controlled by the base angle of a prism without additional microfabrication. In addition, unlike photoresist microneedles, PEGDA does not require any thermal baking, thus enabling well-defined symmetric needle formation with short process time. Therefore, the present method can facilitate PEGDA microneedles to practical applications. [2017-0136]
Autors: H. Takahashi;Y. J. Heo;I. Shimoyama;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Oct 2017, volume: 26, issue:5, pages: 990 - 992
Publisher: IEEE
 
» ScAlN-Based LCAT Mode Resonators Above 2 GHz With High FOM and Reduced Fabrication Complexity
Abstract:
This letter reports the first implementation of a new class of laterally coupled alternating thickness (LCAT) mode resonators operating above 2 GHz, realised by replacing the bottom interdigitated electrodes of the conventional LCAT mode resonator with an electrically floating plate. Besides saving one mask process and relaxing the tight resolution and alignment requirements for defining small features, the flat unpatterned bottom electrode metal is also more favorable for the growth of highly oriented piezoelectric thin film, which results in an improved resonator quality factor (). A group of 8% scandium doped aluminium nitride-based modified LCAT mode resonators with frequency difference over 100 MHz by varying the top interdigitated electrode pitches are fabricated achieving coupling coefficient ( of up to 6.45% and figure of merit of up to 54, making them promising candidates for integrated band selection filter banks.
Autors: Yao Zhu;Nan Wang;Gengli Chua;Chengliang Sun;Navab Singh;Yuandong Gu;
Appeared in: IEEE Electron Device Letters
Publication date: Oct 2017, volume: 38, issue:10, pages: 1481 - 1484
Publisher: IEEE
 
» Scanning the Issue
Abstract:
Overview of Environment Perception for Intelligent Vehicles H. Zhu, K.-V. Yuen, L. Mihaylova, and H. Leung A comprehensive literature review on environment perception for intelligent vehicles is presented. The state-of-the-art algorithms and modeling methods for intelligent vehicles are given, with a summary of their pros and cons. Special attention is paid to methods for lane and road detection, traffic sign recognition, vehicle tracking, behavior analysis, and scene understanding. In addition, the authors provide information about data sets, common performance analysis, and perspectives on future research directions in this area.
Autors: Petros Ioannou;A. V. Bal Balakrishnan;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Oct 2017, volume: 18, issue:10, pages: 2581 - 2583
Publisher: IEEE
 
» Scatterer Localization Using Large-Scale Antenna Arrays Based on a Spherical Wave-Front Parametric Model
Abstract:
In this contribution, an algorithm based on the space-alternating generalized expectation–maximization principle is proposed for estimating the locations of scatterers involved in the last-hops of propagation paths when a large-scale antenna array is used in a receiver for channel measurement. The underlying generic parametric model is constructed under the spherical wave-front assumption, which allows characterizing a path with a new parameter, i.e., the distance between the scatterer at the last-hop of the path and a specific receiving antenna, additional to the conventional parameters characterizing a specular path under the plane wave-front assumption. Cramér–Rao lower bounds of mean squared errors are derived for the parameter estimators in a single-path scenario, and their accuracy is evaluated through Monte Carlo simulations. The performance of the algorithm when being applied in reality is also evaluated through experiments conducted in an office with a carrier frequency of 9.5 GHz, a bandwidth of 500 MHz, and the receiver equipped with a 121-element virtual array. The proposed signal model and algorithm can be extended to the case of localizing the scatterers in the first- and last-hops of paths when large-scale antenna arrays are used in both the transmitter and the receiver.
Autors: Xuefeng Yin;Stephen Wang;Nan Zhang;Bo Ai;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6543 - 6556
Publisher: IEEE
 
» Scene Classification Based on the Fully Sparse Semantic Topic Model
Abstract:
In high spatial resolution (HSR) imagery scene classification, it is a challenging task to recognize the high-level semantics from a large volume of complex HSR images. The probabilistic topic model (PTM), which focuses on modeling topics, has been proposed to bridge the so-called semantic gap. Conventional PTMs usually model the images with a dense semantic representation and, in general, one topic space is generated for all the different features. However, this approach fails to consider the sparsity of the semantic representation, the classification quality, as well as the time consumption. In this paper, to solve the above problems, a fully sparse semantic topic model (FSSTM) framework is proposed for HSR imagery scene classification. FSSTM, with an elaborately designed modeling procedure, is able to represent the image with sparse but representative semantics. Based on this framework, the topic weights of multiple features are exploited by solving a concave maximization problem, which improves the fusion of the discriminative semantic information at the topic level. Meanwhile, the sparsity and representativeness of the topics generated by FSSTM guarantee that the image is adaptive to the change of a topic number. FSSTM can consistently achieve a good performance with a limited number of training samples, and is robust for HSR image scene classification. The experimental results obtained with three different types of HSR image data sets confirm that the proposed algorithm is effective in improving the performance of scene classification, and is highly efficient in discovering the semantics of HSR images when compared with the state-of-the-art PTM methods.
Autors: Qiqi Zhu;Yanfei Zhong;Liangpei Zhang;Deren Li;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5525 - 5538
Publisher: IEEE
 
» Schottky-MOS Hybrid Anode AlGaN/GaN Lateral Field-Effect Rectifier With Low Onset Voltage and Improved Breakdown Voltage
Abstract:
For devices with a 15 micron anode-to-cathode distance, nearly 1.5 times increase in the blocking (breakdown) voltage (from 692 to 1030 V) has been achieved by replacing the alloyed Ohmic contact at the anode electrode of the conventional MOS gated hybrid-anode lateral field-effect rectifier (CMLFER) with a low barrier Schottky contact. The new Schottky-MOS hybrid-anode lateral field-effect rectifier is found to offer comparable low onset voltage ( of 0.68±0.13 versus 0.65±0.11 V for CMLFER) independent of the anode-to- cathode distance. The immunity of the punch through caused by drain induced barrier lowering effect is obtained through the low barrier Schottky contact in anode, which is believed to be responsible for the reduction in the leakage current, and the improvement of rectifier breakdown voltage.
Autors: Jingnan Gao;Maojun Wang;Ruiyuan Yin;Shaofei Liu;Cheng P. Wen;Jinyan Wang;Wengang Wu;Yilong Hao;Yufeng Jin;Bo Shen;
Appeared in: IEEE Electron Device Letters
Publication date: Oct 2017, volume: 38, issue:10, pages: 1425 - 1428
Publisher: IEEE
 
» Scientific Workflow Mining in Clouds
Abstract:
Computing clouds have become the platform of choice for the deployment and execution of scientific workflows. Due to the uncertainty and unpredictability of scientific exploration, the execution plan for a scientific workflow may vary from the definition. It is therefore of great significance to be able to discover actual workflows from execution histories (event logs) to reproduce experimental results and to establish provenance. However, most existing process mining techniques focus on discovering control flow-oriented business processes in a centralized environment, and thus, they are mostly inapplicable to the discovery of data flow-oriented, unstructured scientific workflows in distributed cloud environments. In this paper, we present Scientific Workflow Mining as a Service () to support both intra-cloud and inter-cloud scientific workflow mining. The approach is implemented as a plug-in and is evaluated on event logs derived from real-world scientific workflows. Through experimental results, we demonstrate the effectiveness and efficiency of our approach.
Autors: Wei Song;Fangfei Chen;Hans-Arno Jacobsen;Xiaoxu Xia;Chunyang Ye;Xiaoxing Ma;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Oct 2017, volume: 28, issue:10, pages: 2979 - 2992
Publisher: IEEE
 
» SDNHAS: An SDN-Enabled Architecture to Optimize QoE in HTTP Adaptive Streaming
Abstract:
HTTP adaptive streaming (HAS) is receiving much attention from both industry and academia as it has become the de facto approach to stream media content over the Internet. Recently, we proposed a streaming architecture called SDNDASH [1] to address HAS scalability issues including video instability, quality of experience (QoE) unfairness, and network resource underutilization, while maximizing per player QoE. While SDNDASH was a significant step forward, there were three unresolved limitations: 1) it did not scale well when the number of HAS players increased; 2) it generated communication overhead; and 3) it did not address client heterogeneity. These limitations could result in suboptimal decisions that led to viewer dissatisfaction. To that effect, we propose an enhanced intelligent streaming architecture, called SDNHAS, which leverages software defined networking (SDN) capabilities of assisting HAS players in making better adaptation decisions. This architecture accommodates large-scale deployments through a cluster-based mechanism, reduces communication overhead between the HAS players and SDN core, and allocates the network resources effectively in the presence of short- and long-term changes in the network.
Autors: Abdelhak Bentaleb;Ali C. Begen;Roger Zimmermann;Saad Harous;
Appeared in: IEEE Transactions on Multimedia
Publication date: Oct 2017, volume: 19, issue:10, pages: 2136 - 2151
Publisher: IEEE
 
» Seabed Characterization From Ambient Noise Using Short Arrays and Autonomous Vehicles
Abstract:
Reliable SONAR-performance prediction in shallow water requires knowledge of the seabed reflectivity, or its geoacoustic properties, which is expensive and difficult to acquire in situ. This paper illustrates two sea trials conducted in different shallow water areas to investigate the feasibility of acquiring such knowledge efficiently from measurements of naturally occurring ambient noise by an array that is compact enough to be mounted on a small autonomous underwater vehicle. The system relies on a previous technique for passively estimating the bottom reflection loss from the acoustic noise field generated by wind and breaking waves at the sea surface. Results from these experiments supported by numerical modeling are presented and compared with independent measurements of the relevant seabed reflectivity properties. The results obtained from both experiments demonstrate the potential of using autonomous underwater vehicles for seabed characterization.
Autors: Peter Louring Nielsen;Lanfranco Muzi;Martin Siderius;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Oct 2017, volume: 42, issue:4, pages: 1094 - 1101
Publisher: IEEE
 
» Sealing of Immersion Deuterium Dioxide and Its Application to Signal Maintenance for Ex-Vivo and In-Vivo Multiphoton Microscopy Excited at the 1700-nm Window
Abstract:
Excitation at the 1700-nm window is an effective means for extending imaging depth and imaging modalities in multiphoton microscopy (MPM). To enhance multiphoton signal levels and enable deep-tissue penetration, water immersion has to be replaced by deuterium dioxide (D2O) immersion to boost transmittance at the 1700-nm window. The key problem facing this D2O immersion technique is the hygroscopic nature of D2O, which leads to decrease of MPM signals as time lapses. Here, we demonstrate a simple, yet very effective technique to isolate D2 O from the ambient environment, by sealing it with the paraffin liquid. We demonstrate the application of this technique to MPM signal maintenance in both three-photon fluorescence generation in a fluorescent dye and third-harmonic generation (THG) imaging of biological tissue, excited at the 1700-nm window. Ex-vivo imaging results show that during an imaging session of 5 h, multiphoton signals of both modalities can be maintained with no deterioration due to absorption of water vapor from the environment. Furthermore, we demonstrate in-vivo deep-tissue mouse brain imaging using this technique, in which THG signals can be maintained for at least 5 h. This justifies the applicability and effectiveness of our D2O sealing technique for long-span in-vivo imaging.
Autors: Hongji Liu;Yu Du;Xiao Peng;Xuechang Zhou;Ping Qiu;Ke Wang;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 8
Publisher: IEEE
 
» Second-Order Nonlocal Effects Mitigation in Brillouin Optical Time-Domain Analysis Sensors by Tracking the Brillouin Frequency Shift Profile of the Fiber
Abstract:
We report on an additional limitation that has been found in Brillouin optical time-domain analysis (BOTDA) sensors due to the so-called second-order nonlocal effects (NLE). Second-order NLE appear in BOTDA setups that deploy a double probe waves to compensate the transfer of energy between the pump pulse and the probe wave, and are related to a spectral distortion of the pump pulse that leads to measurement errors and an effective limit on the maximum probe power that can be deployed in the sensor. We theoretically and experimentally demonstrate that the techniques that have been presented so far in the literature to compensate second-order NLE are only effective in the case that the Brillouin frequency shift (BFS) along the sensing fiber is uniform. However, this requirement for uniformity is not realistic in real world scenarios in which a variety of fibers with different BFS and subjected to different environmental conditions are typically deployed. Therefore, we demonstrate a new method to mitigate the effects of BFS variation in the BOTDA setups that compensate second-order NLE. This method is based on introducing an additional wavelength modulation to the probe wave so as to track the mean BFS changes along the sensing fiber link. With this method, we demonstrate a BOTDA setup that, without coding, distributed amplification, or any other form of performance enhancement, achieves a sensing length of 120 km with 3-m spatial resolution and 2-MHz measurement precision. Moreover, the setup demonstrates, to our knowledge, the largest probe power ever injected in a BOTDA sensing link.
Autors: Juan José Mompó;Haritz Iribas;Javier Urricelqui;Alayn Loayssa;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 12
Publisher: IEEE
 
» Second-Order Switching Time Optimization for Switched Dynamical Systems
Abstract:
Switching time optimization arises in finite-horizon optimal control for switched systems where, given a sequence of continuous dynamics, one minimizes a cost function with respect to the switching times. We propose an efficient method for computing the optimal switching times for switched linear and nonlinear systems. A novel second-order optimization algorithm is introduced where, at each iteration, the dynamics are linearized over an underlying time grid to compute the cost function, the gradient, and the Hessian efficiently. With the proposed method, the most expensive operations at each iteration are shared between the cost function and its derivatives, thereby greatly reducing the computational burden. We have implemented the algorithm in the Julia package SwitchTimeOpt, allowing users to easily solve switching time optimization problems. In the case of linear dynamics, many operations can be further simplified and benchmarks show that our approach is able to provide optimal solutions in just a few millisecond. In the case of nonlinear dynamics, our method provides optimal solutions with up to two orders of magnitude time reductions over state-of-the-art approaches.
Autors: Bartolomeo Stellato;Sina Ober-Blöbaum;Paul J. Goulart;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5407 - 5414
Publisher: IEEE
 
» SecRBAC: Secure data in the Clouds
Abstract:
Most current security solutions are based on perimeter security. However, Cloud computing breaks the organization perimeters. When data resides in the Cloud, they reside outside the organizational bounds. This leads users to a loos of control over their data and raises reasonable security concerns that slow down the adoption of Cloud computing. Is the Cloud service provider accessing the data? Is it legitimately applying the access control policy defined by the user? This paper presents a data-centric access control solution with enriched role-based expressiveness in which security is focused on protecting user data regardless the Cloud service provider that holds it. Novel identity-based and proxy re-encryption techniques are used to protect the authorization model. Data is encrypted and authorization rules are cryptographically protected to preserve user data against the service provider access or misbehavior. The authorization model provides high expressiveness with role hierarchy and resource hierarchy support. The solution takes advantage of the logic formalism provided by Semantic Web technologies, which enables advanced rule management like semantic conflict detection. A proof of concept implementation has been developed and a working prototypical deployment of the proposal has been integrated within Google services.
Autors: Juan M. Marín Pérez;Gregorio Martínez Pérez;Antonio F. Skarmeta Gomez;
Appeared in: IEEE Transactions on Services Computing
Publication date: Oct 2017, volume: 10, issue:5, pages: 726 - 740
Publisher: IEEE
 
» Secure Multiple-Antenna Block-Fading Wiretap Channels With Limited CSI Feedback
Abstract:
In this paper, we investigate the ergodic secrecy capacity of a block-fading wiretap channel with limited channel knowledge at the transmitter. We consider that the legitimate receiver, the eavesdropper, and the transmitter are equipped with multiple antennas and that the receiving nodes are aware of their respective channel matrices. On the other hand, the transmitter is only provided by a -bit feedback of the main channel state information. The feedback bits are sent by the legitimate receiver, at the beginning of each fading block, over an error-free public link with limited capacity. The statistics of the main and the eavesdropper channel state information are known at all nodes. Assuming an average transmit power constraint, we establish upper and lower bounds on the ergodic secrecy capacity. Then, we present a framework to design the optimal codebooks for feedback and transmission. In addition, we show that the proposed lower and upper bounds coincide asymptotically, as the capacity of the feedback link becomes large, i.e., , hence fully characterizing the ergodic secrecy capacity in this case. Besides, we analyze the asymptotic behavior of the presented secrecy rates, at high signal-to-noise ratio, and evaluate the gap between the bounds.
Autors: Amal Hyadi;Zouheir Rezki;Mohamed-Slim Alouini;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6618 - 6634
Publisher: IEEE
 
» Secure Polar Coding With REP and XOR Coding
Abstract:
In this letter, we study the secure data communication by polar coding. In polar coding, all bit-channels perfectly polarize when the codelength goes to infinity. With finite and practical codelength, however, many bit-channels do not perfectly polarize and this significantly degrades the secrecy rate. To address this issue, we propose to use repetition (REP) coding and exclusive-or (XOR) coding combined with polar coding. To make the proposed approach practical, we develop simple design methods for REP and XOR codings. Numerical results demonstrate that the proposed secure polar coding improves the secrecy rate and security gap considerably.
Autors: Il-Min Kim;Byoung-Hoon Kim;Joon Kui Ahn;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2126 - 2129
Publisher: IEEE
 
» Secure State Estimation for Cyber-Physical Systems Under Sensor Attacks: A Satisfiability Modulo Theory Approach
Abstract:
Secure state estimation is the problem of estimating the state of a dynamical system from a set of noisy and adversarially corrupted measurements. Intrinsically a combinatorial problem, secure state estimation has been traditionally addressed either by brute force search, suffering from scalability issues, or via convex relaxations, using algorithms that can terminate in polynomial time but are not necessarily sound. In this paper, we present a novel algorithm that uses a satisfiability modulo theory approach to harness the complexity of secure state estimation. We leverage results from formal methods over real numbers to provide guarantees on the soundness and completeness of our algorithm. Moreover, we discuss its scalability properties, by providing upper bounds on the runtime performance. Numerical simulations support our arguments by showing an order of magnitude decrease in execution time with respect to alternative techniques. Finally, the effectiveness of the proposed algorithm is demonstrated by applying it to the problem of controlling an unmanned ground vehicle.
Autors: Yasser Shoukry;Pierluigi Nuzzo;Alberto Puggelli;Alberto L. Sangiovanni-Vincentelli;Sanjit A. Seshia;Paulo Tabuada;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 4917 - 4932
Publisher: IEEE
 
» Security Analysis of Password-Authenticated Key Retrieval
Abstract:
A PAKR (Password-Authenticated Key Retrieval) protocol and its multi-server system allow one party (say, client), who has a memorable password, to retrieve a long-term static key in an exchange of messages with at least one other party (say, server) that has a private key associated with the password. In this paper, we analyze the only PAKR (named as PKRS-1) standardized in IEEE 1363.2 [9] and its multi-server system (also, [12]) by showing that any passive/ active attacker can find out the client's password and the static key with off-line dictionary attacks. This result contradicts the security claims made for PKRS-1 (see Clause 10.2 of IEEE 1363.2 [9]).
Autors: SeongHan Shin;Kazukuni Kobara;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Oct 2017, volume: 14, issue:5, pages: 573 - 576
Publisher: IEEE
 
» SeeR: Simulated Annealing-Based Routing in Opportunistic Mobile Networks
Abstract:
Opportunistic Mobile Networks (OMNs) are characterized by intermittent connectivity among nodes. In many scenarios, the nodes attempt at local decision making based on greedy approaches, which can result in getting trapped at local optimum. Moreover, for efficient routing, the nodes often collect and exchange a lot of information about others. To alleviate such issues, we present SeeR, a simulated annealing-based routing protocol for OMNs. In SeeR, each message is associated with a cost function, which is evaluated by considering its current hop-count and the average aggregated inter-contact time of the node. A node replicates a message to another node, when the latter offers a lower cost. Otherwise, the message is replicated with decreasing probability. Moreover, SeeR works based solely upon local observations. In particular, a node does not track information about other nodes, and, therefore, reduces the risk of privacy leaks unlike many other protocols. We evaluated the performance of SeeR by considering several real-life traces under plausible conditions. Experimental results show that, in the best case, SeeR can reduce the average message delivery latency by about 58 percent, when compared to other popular routing protocols.
Autors: Barun Kumar Saha;Sudip Misra;Sujata Pal;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Oct 2017, volume: 16, issue:10, pages: 2876 - 2888
Publisher: IEEE
 
» Segmentation of 3-D High-Frequency Ultrasound Images of Human Lymph Nodes Using Graph Cut With Energy Functional Adapted to Local Intensity Distribution
Abstract:
Previous studies by our group have shown that 3-D high-frequency quantitative ultrasound (QUS) methods have the potential to differentiate metastatic lymph nodes (LNs) from cancer-free LNs dissected from human cancer patients. To successfully perform these methods inside the LN parenchyma (LNP), an automatic segmentation method is highly desired to exclude the surrounding thin layer of fat from QUS processing and accurately correct for ultrasound attenuation. In high-frequency ultrasound images of LNs, the intensity distribution of LNP and fat varies spatially because of acoustic attenuation and focusing effects. Thus, the intensity contrast between two object regions (e.g., LNP and fat) is also spatially varying. In our previous work, nested graph cut (GC) demonstrated its ability to simultaneously segment LNP, fat, and the outer phosphate-buffered saline bath even when some boundaries are lost because of acoustic attenuation and focusing effects. This paper describes a novel approach called GC with locally adaptive energy to further deal with spatially varying distributions of LNP and fat caused by inhomogeneous acoustic attenuation. The proposed method achieved Dice similarity coefficients of 0.937±0.035 when compared with expert manual segmentation on a representative data set consisting of 115 3-D LN images obtained from colorectal cancer patients.
Autors: Jen-wei Kuo;Jonathan Mamou;Yao Wang;Emi Saegusa-Beecroft;Junji Machi;Ernest J. Feleppa;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Oct 2017, volume: 64, issue:10, pages: 1514 - 1525
Publisher: IEEE
 
» Selective Sampling Versus Attenuation for Interference Mitigation in Broadband Receivers
Abstract:
In a filterless broadband receiver, time selective sampling (SS) is a method for mitigating interference effects by time sampling the amplified input (message plus interference) signal and discarding all samples that are big enough to be distorted. A consequence is that a longer total sampling time is necessary to compensate for the discarded samples. An alternative technique is to reduce amplifier gain and thereby reduce distortion. This also requires a longer total sampling time to make up for lost signal-to-noise. This brief compares the two techniques using a simplified analysis that is verified by comparison to simulation. The analysis provides insight into how the performance of each technique depends on interference power, noise, nonlinearity, and message power. SS takes significantly less time than attenuation to achieve equally accurate message extraction. For large interference levels the difference can be an order of magnitude.
Autors: Robert W. Jackson;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Oct 2017, volume: 64, issue:10, pages: 1167 - 1171
Publisher: IEEE
 
» Self-Aligned AlGaN/GaN FinFETs
Abstract:
We have demonstrated highly scaled, self-aligned AlGaN/GaN fin-shaped field-effect transistors (FinFETs), which were fabricated using e-beam lithography and a regrown n+ GaN ohmic process with a sacrificial dummy gate. Our devices were very aggressively scaled, with fin widths, gate length, and source drain spacing as small as 50, 60, and 200nm, respectively. DC characteristics, when normalized to active device periphery (number of fins times fin width), showed peak transconductance of 1.5 mS/ and ON resistance of -. Enhancement mode device operation was observed for fin widths below 100 nm.
Autors: David F. Brown;Yan Tang;Dean Regan;Joel Wong;Miroslav Micovic;
Appeared in: IEEE Electron Device Letters
Publication date: Oct 2017, volume: 38, issue:10, pages: 1445 - 1448
Publisher: IEEE
 
» Self-Aligned, Gate Last, FDSOI, Ferroelectric Gate Memory Device With 5.5-nm Hf0.8Zr0.2O2, High Endurance and Breakdown Recovery
Abstract:
We demonstrate a nonvolatile single transistor ferroelectric gate memory device with ultra-thin (5.5 nm) Hf0.8Zr0.2O2 (HZO) fabricated using a self-aligned gate last process. The FETs are fabricated using silicon-on-insulator wafers, and the ferroelectric is deposited with atomic layer deposition. The reported devices have an ON/OFF drain current ratio of up to 106, a read endurance of read cycles, and a program/erase endurance of 107 cycles. Furthermore, healing of the transistor after gate insulator breakdown is demonstrated.
Autors: Korok Chatterjee;Sangwan Kim;Golnaz Karbasian;Ava J. Tan;Ajay K. Yadav;Asif I. Khan;Chenming Hu;Sayeef Salahuddin;
Appeared in: IEEE Electron Device Letters
Publication date: Oct 2017, volume: 38, issue:10, pages: 1379 - 1382
Publisher: IEEE
 
» Self-Calibrated and Extinction-Ratio-Independent Microwave Characterization of Electrooptic Mach–Zehnder Modulators
Abstract:
A self-calibrated and extinction-ratio (ER)-independent electrical method based on frequency-shifted heterodyne is proposed for full microwave characterization of high-speed electrooptic Mach–Zehnder modulators (MZMs) with finite or infinite ER. The method eliminates the need for correcting the roll-off responsivity in the photodetection and reduces half bandwidth requirements for the photodetector and electrical spectrum analyzer. Modulation depths, half-wave voltages, chirp parameters, and asymmetric factor are experimentally measured for an MZM, which agree well with the results obtained by the optical spectrum analysis method.
Autors: Heng Wang;Shangjian Zhang;Xinhai Zou;Zhiyao Zhang;Yali Zhang;Shuang Liu;Yong Liu;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Oct 2017, volume: 27, issue:10, pages: 948 - 950
Publisher: IEEE
 
» Self-driving wheelchairs debut in hospitals and airports [News]
Abstract:
Autonomous vehicles can add a new member to their ranks-the self-driving wheelchair. This summer, two robotic wheelchairs made headlines: one at a Singaporean hospital and another at a Japanese airport. The Singapore-MIT Alliance for Research and Technology, or SMART, developed the former, first deployed in Singapore's Changi General Hospital in September 2016, where it successfully navigated the hospital's hallways. It is the latest in a string of autonomous vehicles made by SMART, including a golf cart, an electric taxi, and most recently, a scooter that zipped more than 100 MIT visitors around on tours in 2016.
Autors: Megan Scudellari;
Appeared in: IEEE Spectrum
Publication date: Oct 2017, volume: 54, issue:10, pages: 14 - 14
Publisher: IEEE
 
» Self-Powered Artificial Sensory Nervous System Using Ring Oscillator for Pulse Density Modulation
Abstract:
Unlike typical sensor electronics that always require a voltage source for sensors, amplifiers, and analog-digital converters, we use a mechano-electric transducer as a sensor and also in place of a power source to drive the rest of the electronics, thereby realizing an autonomous self-powered artificial sensory nervous system. A piezoelectric (lead zirconate titanate oxide) PZT is used as an inertia sensor that produces a voltage signal as a function of the acceleration of incoming vibrations. The PZT output current is rectified and stored in a capacitor to develop a time-varying dc voltage of typically upward of 1 V, which is used to drive a subsequent three-stage ring oscillator. The running frequency of the ring oscillator is voltage-controlled by three orders of magnitude from 2.1 kHz to 1.3 MHz within a single period of the sinusoidal waveform of acceleration that has the acceleration of 9 m/ at 160 Hz. By repeatedly counting the number of pulses in an every 6.3-ms time frame, the original waveform of the incoming acceleration is reproduced as a digital data. Dynamic range is defined by the frequency shift from 2.1 kHz to 3 MHz when the acceleration amplitude is changed from 6 to 12 m/, thereby yielding a sensitivity of 240 /m.
Autors: S. Yamada;H. Toshiyoshi;
Appeared in: IEEE Electron Device Letters
Publication date: Oct 2017, volume: 38, issue:10, pages: 1477 - 1480
Publisher: IEEE
 
» Self-Tuning Mode-Locked Fiber Lasers Based on Prior Collection of Polarization Settings
Abstract:
We present a method to discriminate stable mode-locked states of an all fiber erbium-doped laser based on nonlinear polarization rotation mechanism. The method has a balance between the accuracy and rapidness of the pulses discrimination. Mode-locked states are distinguished and confirmed by an amplitude discriminator, which reflects the repetition rate information of the pulses. An electronic polarization controller is used to precisely adjust the intracavity polarization states. The driving voltages of the electronic polarization controller at those mode-locked states are recorded as populations, and it is benefit to reduce the build-up time for mode locking. The populations are also recorded at operation temperature covering from 20 °C to 50 °C, which exhibits the repeatability and stability of the mode-locked states. Rapid self-tuning mode-locked fiber lasers could be achieved by the repeatability of the polarization settings under the stable temperature environment.
Autors: Xuling Shen;Qiang Hao;Heping Zeng;
Appeared in: IEEE Photonics Technology Letters
Publication date: Oct 2017, volume: 29, issue:20, pages: 1719 - 1722
Publisher: IEEE
 
» Sensitive Load Voltage Compensation Performed by a Suitable Control Method
Abstract:
This paper proposes the usage of a repetitive-based control to dynamically restore the voltage applied to sensitive and critical loads of power system. The control intrinsically is able to wipe off harmonic distortion and relies on simple transfer function. As a consequence, there is no need to apply harmonic selective filters. Furthermore, the control system is able to work out on sinusoid references and, thus, avoids the need of employing the dq transform. A recursive least-squares is also included to the control system in order to assure the synchronization of the voltages to be restored. The design of the control parameters along with the system stability is discussed. The experimental results are produced with a setup of a three-phase series compensator. The scenarios for emulating faulty voltages are the same for experimental and simulated results. The results corroborates the usage of the proposed method.
Autors: Darlan A. Fernandes;Fabiano F. Costa;João R. S. Martins;Alberto Soto Lock;Edison R. C. da Silva;Montiê Alves Vitorino;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4877 - 4885
Publisher: IEEE
 
» Sensitivity Enhancement for Low-Coherence Interferometry
Abstract:
In this letter, a sensitivity improvement for systems combining low-coherence interferometry (LCI) and microwave photonics (MWP) is demonstrated. This improvement is due to the introduction of a different modulation format and an exhaustive control of the optical source profile compared with previous MWP-LCI schemes. Our proposal allows to retrieve the visibility of low-coherence interferograms through the analysis of the interference pattern using a dispersive element. We demonstrate that the use of a phase modulator offers better stability and lower insertion loss since a bias point configuration is not needed compared with the intensity modulators typically used in these schemes. The process for controlling the optical source profile permits a comparison between uniform and Gaussian profiles. In this way, the limiting effects of the sidelobes over the achieved sensitivity level are analyzed. The proposed MWP-LCI structure is experimentally demonstrated through the characterization of the electrical transfer function. In this case, a maximum sensitivity of 65 dB is achieved in our MWP-LCI structure showing a 30-dB improvement compared with current proposals.
Autors: J. Benítez;J. Mora;
Appeared in: IEEE Photonics Technology Letters
Publication date: Oct 2017, volume: 29, issue:20, pages: 1735 - 1738
Publisher: IEEE
 
» Sensor Fault Diagnosis and System Reconfiguration Approach for an Electric Traction PWM Rectifier Based on Sliding Mode Observer
Abstract:
Single-phase pulse-width modulation (PWM) rectifier is commonly used in a high-speed railway electric traction system. Occurrence of unexpected failure in the sensors of the detection system may lead to feedback values deviation and system degradation, which can be extremely detrimental to the operation safety of the electric locomotive. This paper presents a fast and reliable fault diagnosis and fault resilient control strategy for catenary current and dc-link voltage sensor faults in the control system for an electric traction single-phase PWM rectifier. Sliding mode observers are designed to produce analytical redundancy. In order to avoid unobservable states and fluctuation introduced by discrete dynamics in observer design, a novel description for switching variables is presented in system modeling. Normalized residuals are generated using measured and observed values. The fault diagnosis unit proposed can detect and isolate three types of sensor faults online by comparing residuals with thresholds. System reconfiguration is realized by substituting the observed values for the information of faulty sensors. Simulation and experimental results are demonstrated to validate the effectiveness of the strategy.
Autors: Jinhui Xia;Yuanbo Guo;Bijun Dai;Xiaohua Zhang;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4768 - 4778
Publisher: IEEE
 
» Sensor-Based Change Detection for Timely Solicitation of User Engagement
Abstract:
The accurate detection of changes has the potential to form a fundamental component of systems which autonomously solicit user interaction based on transitions within an input stream, for example, electrocardiogram data or accelerometry obtained from a mobile device. This solicited interaction may be utilized for diverse scenarios such as responding to changes in a patient's vital signs within a medical domain or requesting user activity labels for generating real-world labelled datasets. Within this paper, we extend our previous work on the Multivariate Online Change detection Algorithm subsequently exploring the utility of incorporating the Benjamini Hochberg method of correcting for multiple comparisons. Furthermore, we evaluate our approach against similarly light-weight Multivariate Exponentially Weighted Moving Average and Cumulative Sum based techniques. Results are presented based on manually labelled change points in accelerometry data captured using 10 participants. Each participant performed nine distinct activities for a total period of 35 minutes. The results subsequently demonstrate the practical potential of our approach from both accuracy and computational perspectives.
Autors: Timothy Patterson;Naveed Khan;Sally McClean;Chris Nugent;Shuai Zhang;Ian Cleland;Qin Ni;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Oct 2017, volume: 16, issue:10, pages: 2889 - 2900
Publisher: IEEE
 
» Sequential Estimator: Toward Efficient InSAR Time Series Analysis
Abstract:
Wide-swath synthetic aperture radar (SAR) missions with short revisit times, such as Sentinel-1 and the planned NISAR and Tandem-L, provide an unprecedented wealth of interferometric SAR (InSAR) time series. However, the processing of the emerging Big Data is challenging for state-of-the-art InSAR analysis techniques. This contribution introduces a novel approach, named Sequential Estimator, for efficient estimation of the interferometric phase from long InSAR time series. The algorithm uses recursive estimation and analysis of the data covariance matrix via division of the data into small batches, followed by the compression of the data batches. From each compressed data batch artificial interferograms are formed, resulting in a strong data reduction. Such interferograms are used to link the “older” data batches with the most recent acquisitions and thus to reconstruct the phase time series. This scheme avoids the necessity of reprocessing the entire data stack at the face of each new acquisition. The proposed estimator introduces negligible degradation compared to the Cramér–Rao lower bound under realistic coherence scenarios. The estimator may therefore be adapted for high-precision near-real-time processing of InSAR and accommodate the conversion of InSAR from an offline to a monitoring geodetic tool. The performance of the Sequential Estimator is compared to state-of-the-art techniques via simulations and application to Sentinel-1 data.
Autors: Homa Ansari;Francesco De Zan;Richard Bamler;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5637 - 5652
Publisher: IEEE
 
» Service Rate Control of Tandem Queues With Power Constraints
Abstract:
In this paper, we study the optimal control of service rates of a tandem queue with power constraints. The service rate of a server is determined by the power allocated to that server. The total power of the system is fixed. The system cost is comprised of two parts, the holding cost reflecting the congestion of queues and the operating cost reflecting the power consumed at servers. The optimization objective is to find the optimal power allocation policy among servers, which can minimize the system average cost. We formulate this problem as a Markov decision process with a constrained action space. Sensitivity-based optimization theory is applied to study this problem. The necessary and sufficient condition of optimal service rates, and the optimality of the vertexes of the feasible domain are derived when the operating cost has a linear or concave form. An iterative algorithm is further developed to find the optimal service rates. This algorithm may work well even when the cost function has a general form. The extension to general tandem queues with many servers is also studied. Finally, we conduct numerical experiments under different parameter settings to demonstrate the main idea of this paper.
Autors: Li Xia;Daniel Miller;Zhengyuan Zhou;Nicholas Bambos;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5111 - 5123
Publisher: IEEE
 
» Service-Oriented Architecture on FPGA-Based MPSoC
Abstract:
The integration of software services-oriented architecture (SOA) and hardware multiprocessor system-on-chip (MPSoC) has been pursued for several years. However, designing and implementing a service-oriented system for diverse applications on a single chip has posed significant challenges due to the heterogeneous architectures, programming interfaces, and software tool chains. To solve the problem, this paper proposes SoSoC, a service-oriented system-on-chip framework that integrates both embedded processors and software defined hardware accelerators s as computing services on a single chip. Modeling and realizing the SOA design principles, SoSoC provides well-defined programming interfaces for programmers to utilize diverse computing resources efficiently. Furthermore, SoSoC can provide task level parallelization and significant speedup to MPSoC chip design paradigms by providing out-of-order execution scheme with hardware accelerators. To evaluate the performance of SoSoC, we implemented a hardware prototype on Xilinx Virtex5 FPGA board with EEMBC benchmarks. Experimental results demonstrate that the service componentization over original version is less than 3 percent, while the speedup for typical software Benchmarks is up to 372x. To show the portability of SoSoC, we implement the convolutional neural network as a case study on both Xilinx Zynq and Altera DE5 FPGA boards. Results show the SoSoC outperforms state-of-the-art literature with great flexibility.
Autors: Chao Wang;Xi Li;Yunji Chen;Youhui Zhang;Oliver Diessel;Xuehai Zhou;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Oct 2017, volume: 28, issue:10, pages: 2993 - 3006
Publisher: IEEE
 
» Service-Oriented Dynamic Connection Management for Software-Defined Internet of Vehicles
Abstract:
Internet of vehicles (IoV) is an emerging paradigm for accommodating the requirements of future intelligent transportation systems (ITSs) with the overwhelming trend of equipping vehicles with versatile sensors and communications modules, and facilitating drivers and passengers with a variety of innovative ITS applications. However, the implementation of IoV still faces many challenges, such as flexible and efficient connections, quality of service guarantee, and multiple concurrent support requests. To this end, in this paper we introduce the software-defined IoV (SD-IoV), which is able to tackle the above-mentioned issues by adopting the software-defined networking framework. We first present the architecture of SD-IoV and develop a centralized vehicular connection management approach. Then, we aim to allocate dedicated communications resources and underlying vehicular nodes to satisfy each service. We formulate the dynamic vehicular connection as an overlay vehicular network creation (OVNC) problem. A comprehensive utility function is also designed to serve as the optimization objective of OVNC. Finally, we solve the OVNC problem by developing a graph-based genetic algorithm and a heuristic algorithm, respectively. Extensive simulation results are provided to demonstrate the effectiveness of our proposed solution of dynamic vehicular connection management.
Autors: Jiacheng Chen;Haibo Zhou;Ning Zhang;Wenchao Xu;Quan Yu;Lin Gui;Xuemin Shen;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Oct 2017, volume: 18, issue:10, pages: 2826 - 2837
Publisher: IEEE
 
» Set-Membership Type-1 Fuzzy Logic System Applied to Fault Classification in a Switch Machine
Abstract:
This paper focuses on the classification of faults in an electromechanical switch machine, which is an equipment used for handling railroad switches. In this paper, we introduce the use of Set-Membership concept, derived from the adaptive filter theory, into the training procedure of type-1 and singleton/non-singleton fuzzy logic systems, in order to reduce computational complexity and to increase convergence speed. We also present different criteria for using along with Set-Membership. Furthermore, we discuss the usefulness of delta rule delta, local Lipschitz estimation, variable step size, and variable step size adaptive techniques to yield additional improvement in terms of computational complexity reduction and convergence speed. Based on data set provided by a Brazilian railway company, which covers the four possible faults in a switch machine, we present performance analysis in terms of classification ratio, convergence speed, and computational complexity reduction. The reported results show that the proposed models result in improved convergence speed, slightly higher classification ratio, and remarkable computation complexity reduction when we limit the number of epochs for training, which may be required due to real-time constraint or low computational resource availability.
Autors: Eduardo P. de Aguiar;Fernando M. de A. Nogueira;Marley M. B. R. Vellasco;Moisés V. Ribeiro;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Oct 2017, volume: 18, issue:10, pages: 2703 - 2712
Publisher: IEEE
 
» ShakeIn: Secure User Authentication of Smartphones with Single-Handed Shakes
Abstract:
Smartphones have been widely used with a vast array of sensitive and private information stored on these devices. To secure such information from being leaked, user authentication schemes are necessary. Current password/pattern-based user authentication schemes are vulnerable to shoulder surfing attacks and smudge attacks. In contrast, stroke/gait-based schemes are secure but inconvenient for users to input. In this paper, we propose ShakeIn, a handy user authentication scheme for secure unlocking of a smartphone by simply shaking the phone. With embedded motion sensors, ShakeIn can effectively capture the unique and reliable biometrical features of users about howthey shake. In this way, even if an attacker sees a user shaking his/her phone, the attacker can hardly reproduce the same behavior. Furthermore, by allowing users to customize the way they shake the phone, ShakeIn endows users with the maximum operation flexibility. We implement ShakeIn and conduct both intensive trace-driven simulations and real experiments on 20 volunteers with about 530,555 shaking samples collected over multiple months. The results show that ShakeIn achieves an average equal error rate of 1.2 percent with a small number of shakes using only 35 training samples even in the presence of shoulder-surfing attacks.
Autors: Hongzi Zhu;Jingmei Hu;Shan Chang;Li Lu;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Oct 2017, volume: 16, issue:10, pages: 2901 - 2912
Publisher: IEEE
 
» Shape and Spatially-Varying Reflectance Estimation from Virtual Exemplars
Abstract:
This paper addresses the problem of estimating the shape of objects that exhibit spatially-varying reflectance. We assume that multiple images of the object are obtained under a fixed view-point and varying illumination, i.e., the setting of photometric stereo. At the core of our techniques is the assumption that the BRDF at each pixel lies in the non-negative span of a known BRDF dictionary. This assumption enables a per-pixel surface normal and BRDF estimation framework that is computationally tractable and requires no initialization in spite of the underlying problem being non-convex. Our estimation framework first solves for the surface normal at each pixel using a variant of example-based photometric stereo. We design an efficient multi-scale search strategy for estimating the surface normal and subsequently, refine this estimate using a gradient descent procedure. Given the surface normal estimate, we solve for the spatially-varying BRDF by constraining the BRDF at each pixel to be in the span of the BRDF dictionary; here, we use additional priors to further regularize the solution. A hallmark of our approach is that it does not require iterative optimization techniques nor the need for careful initialization, both of which are endemic to most state-of-the-art techniques. We showcase the performance of our technique on a wide range of simulated and real scenes where we outperform competing methods.
Autors: Zhuo Hui;Aswin C. Sankaranarayanan;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Oct 2017, volume: 39, issue:10, pages: 2060 - 2073
Publisher: IEEE
 
» Ship Classification in Moderate-Resolution SAR Image by Naive Geometric Features-Combined Multiple Kernel Learning
Abstract:
Compared with the high-resolution synthetic aperture radar (SAR) image, a moderate-resolution SAR image can offer wider swath, which is more suitable for maritime ship surveillance. Taking into account the amount of information in a moderate-resolution SAR image and the stability of feature extraction, we propose naive geometric features (NGFs) for ship classification. In contrast to the strictly defined geometric features (SGFs), the extraction of NGFs is very simpler and efficient. And more importantly, the NGFs are enough to reveal the essential difference between different types of ships for classification. To fuse various NGFs with different physical properties and discriminability, the multiple kernel learning (MKL) is utilized to learn the combination weights, rather than assigning the same weight to all features as usually applied by the traditional support vector machines (SVMs). The comprehensive experiments validate that: 1) the performance of the proposed NGF-combined MKL outperforms that of NGF-combined SVM by 3.4% and is very close to that obtained by SGF-combined MKL and 2) in terms of classifying ships in a moderate-resolution SAR image, NGFs are more feasible than scattering features.
Autors: Haitao Lang;Siwen Wu;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1765 - 1769
Publisher: IEEE
 
» Shop Floor Control: A Physical Agents Approach for PLC-Controlled Systems
Abstract:
Multiagent technology raised great expectations from the outset, and these expectations are still high today. A technology that allows the creation of systems that are autonomous, reactive, proactive, and have entities with social skills is necessarily very appealing. Many initiatives have emerged to develop the application of this technology in different areas, including manufacturing. Multiagent-based solutions typically use this technology to create distributed systems with decentralized decision making as a way to tackle complex systems or problems by dividing the complexity among agents. Unfortunately, most works do not go further than the definition of agents or architectures, which prevents industry from adopting this technology. This paper presents an approach to implementing the shop floor control of an automated distribution center following a multiagent approach. This implementation divides the system into agents in charge of the management of the system while highlighting the communication channels with shop floor control equipment.
Autors: Javier de las Morenas;Andrés García-Higuera;Pablo García-Ansola;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2417 - 2427
Publisher: IEEE
 
» Short Courses [Courses]
Abstract:
Presents a listing on online courses in the field of antennas and propagation.
Autors: Raymond P. Wasky;
Appeared in: IEEE Antennas and Propagation Magazine
Publication date: Oct 2017, volume: 59, issue:5, pages: 114 - 115
Publisher: IEEE
 
» Shrunk-2-D: A Physical Design Methodology to Build Commercial-Quality Monolithic 3-D ICs
Abstract:
Monolithic 3-D (M3D) integrated circuits (ICs) are an emerging technology that offer much higher integration densities than previous 3-D IC approaches. In this paper, we present a complete netlist-to-layout design flow to design an M3D block, as well as to integrate 2-D and 3-D blocks into an M3D SoC. This design flow is based on commercial tools built for 2-D ICs, and enhanced with our 3-D specific methodologies. We use the OpenSPARC T2 SoC as a case study, implement it in a 28-nm fully depleted silicon on insulator foundry process, and demonstrate that we can achieve up to 12% and 8% power savings for a single block and SoC, respectively, when compared with their 2-D counterparts implemented using commercial tools.
Autors: Shreepad Panth;Kambiz Samadi;Yang Du;Sung Kyu Lim;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Oct 2017, volume: 36, issue:10, pages: 1716 - 1724
Publisher: IEEE
 
» ShuffleDog: Characterizing and Adapting User-Perceived Latency of Android Apps
Abstract:
Numerous complains have been made by Android users who severely suffer from the sluggish response when interacting with their devices. However, very few studies have been conducted to understand the user-perceived latency or mitigate the UI-lagging problem. In this paper, we conduct the first systematic measurement study to quantify the user-perceived latency using typical interaction-intensive Android apps in running with and without background workloads. We reveal the insufficiency of Android system in ensuring the performance of foreground apps and therefore design a new system to address the insufficiency accordingly. We develop a lightweight tracker to accurately identify all delay-critical threads that contribute to the slow response of user interactions. We then build a resource manager that can efficiently schedule various system resources including CPU, I/O, and GPU, for optimizing the performance of these threads. We implement the proposed system on commercial smartphones and conduct comprehensive experiments to evaluate our implementation. Evaluation results show that our system is able to significantly reduce the user-perceived latency of foreground apps in running with aggressive background workloads, up to 10x, while incurring negligible system overhead of less than 3.1 percent CPU and 7 MB memory.
Autors: Gang Huang;Mengwei Xu;Felix Xiaozhu Lin;Yunxin Liu;Yun Ma;Saumay Pushp;Xuanzhe Liu;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Oct 2017, volume: 16, issue:10, pages: 2913 - 2926
Publisher: IEEE
 
» Shunt Active Power Filter Based on Cascaded Transformers Coupled With Three-Phase Bridge Converters
Abstract:
This paper proposes a multilevel shunt active power filter (SAPF) to deal with either harmonic current compensation or reactive power compensation. Such a device can reduce the harmonic distortion at the grid currents provided by nonlinear loads located in stiff systems. The proposed SAPF is based on three-phase bridge converters connected to cascaded single-phase transformers. The transformer arrangement permits the compensator to use a single dc-link unit, which simplifies the control strategy and the number of sensors. The multilevel waveforms are generated by using a suitable pulse-width modulation (PWM) strategy associated with the transformer turns ratio. Modularity and simple maintenance make the proposed SAPF an attractive solution compared with some conventional configurations. The model, the PWM technique, and the control strategy are presented, as well as studies considering harmonic distortion and semiconductor losses estimation. Simulation and experimental results are presented in order to validate theoretical approaches.
Autors: Gregory Arthur de Almeida Carlos;Cursino Brandão Jacobina;João Paulo Ramos Agra Méllo;Euzeli Cipriano dos Santos;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4673 - 4681
Publisher: IEEE
 
» Side-by-Side Comparison of Single- and Dual-Active Layer Oxide TFTs: Experiment and TCAD Simulation
Abstract:
Single-active layer (SAL) and dual-active layer (DAL) oxide thin-film transistors (TFTs) are fabricated using the same process conditions and compared side by side. The SAL channel consists of amorphous In–Ga–Zn–O (a-IGZO), and the DAL of ultrathin In–Sn–O and a-IGZO. The DAL TFT exhibits strongly improved performance compared to the SAL TFT such as higher mobility of 31 cm, smaller subthreshold swing of 175 mV/dec, and better positive bias temperature stress stability. Technology computer-aided design simulation is used to investigate the SAL and DAL device performance. A mapping technique is used to directly correlate the transfer characteristics to the subbandgap density of states. The simulation suggests that the improved performance of the DAL TFT is due to an improved gate insulator/channel interface with an approximately one order of magnitude lower interface trap density.
Autors: Kevin A. Stewart;Vasily Gouliouk;John M. McGlone;John F. Wager;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4131 - 4136
Publisher: IEEE
 
» Silicon-Based Single-Mode On-Chip Ultracompact Microdisk Resonators With Standard Silicon Photonics Foundry Process
Abstract:
A silicon-based on-chip ultracompact microdisk resonator (MDR) with a super-high Q-factor to support single-mode operation is designed, fabricated, and tested. In our design, a compact MDR has an ultrasmall radius of 3.7 μm with an additional slab waveguide incorporated to wrap the disk and the bus waveguide with an aim to weaken the disk sidewall roughness, to increase the confinement of the optical field and to strengthen the optical coupling between the bus waveguide and the disk. By using the three-level etching capability offered by a standard silicon photonics foundry, two ultracompact MDRs with two different heights of 220 and 150 nm are fabricated, in which the incorporated slab waveguide is kept to have an identical height of 60 nm. Optical performance of the MDRs is evaluated. The measured transmission spectrums show that both the MDRs are operating in single mode with no resonance splitting observed. The MDR with a height of 220 nm has a significantly improved Q-factor of 75,000, which is useful for narrowband filtering. The MDR with a height of 150 nm has a strong energy distribution around the top surface of the disk, which is useful for refractive index sensing. In addition, for the MDR with a height of 220 nm, owing to its ultrahigh light-confining capacity and ultracompact mode volume in the MDR, nonlinear optical response in the cavity is considerably enhanced and an optical bistability is observed experimentally when the input optical power is as small as −17 dBm.
Autors: Weifeng Zhang;Jianping Yao;
Appeared in: Journal of Lightwave Technology
Publication date: Oct 2017, volume: 35, issue:20, pages: 4418 - 4424
Publisher: IEEE
 
» Silo and Tank Vision: Applica?tions, Challenges, and Technical Solutions for Radar Measurement of Liquids and Bulk Solids in Tanks and Silos
Abstract:
In today's industrialized world, the handling of raw materials and goods is an essential part of the supply chain. Liquids-for example water, oil, chemicals, pharmaceutical products, and liquefied gases-are stored in tanks. Bulk solids, on the other hand, are stored in silos and cover a very large variety of materials. Examples include finely granulated substances (grains, powders, sand, plastic pellets, and so forth) and also very rough materials like stones, coal, and others. The operator of a storage system is, in either case, interested in measuring the filling volume to be able to plan removal and refilling-which is important to ensure the continuous production and delivery of materials on schedule.
Autors: Michael Vogt;Michael Gerding;
Appeared in: IEEE Microwave Magazine
Publication date: Oct 2017, volume: 18, issue:6, pages: 38 - 51
Publisher: IEEE
 
» Simple Size Determination of Permanent-Magnet Synchronous Machines
Abstract:
Today, performance improvements such as reducing the time response and enhancing the efficiency of the electrical motor are one of the most important challenges. In the design of a permanent-magnet (PM) motor, the variables for sizing include the shape ratio (SR), the torque per rotor volume (TRV), and the torque density (TD), and these variables are important for determining the mechanical and electrical characteristics of the motor. This study investigated the changing patterns of the motor parameters (back electromotive force, inductance, resistance, etc.) and the motor characteristics with the changes in the SR, TRV, and TD with respect to the PM synchronous motor, and sought to determine the SR and TRV values. Toward these ends, this study proceeded with the initial design of the spoke-type (flux-concentrated) PM motor. Then, the motor parameters of the initial model were calculated using finite-element analysis. Based on the motor parameters of the initial model, the changing patterns of the electrical and mechanical characteristics of the motor according to the changes in the SR, TRV, and TD were investigated. In addition, the SR, TRV, or split ratio that can enhance the mechanical characteristics and efficiency of the motor were determined and reflected in the design.
Autors: Hae-Joong Kim;Jae-Sik Jeong;Myung-Hwan Yoon;Jae-Won Moon;Jung-Pyo Hong;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 7972 - 7983
Publisher: IEEE
 
» Simplified Unified Analysis of Switched-RC Passive Mixers, Samplers, and $N$ -Path Filters Using the Adjoint Network
Abstract:
Recent innovations in software defined CMOS radio transceiver architectures heavily rely on high-linearity switched-RC sampler and passive-mixer circuits, driven by digitally programmable multiphase clocks. Although seemingly simple, the frequency domain analysis of these linear periodically time variant (LPTV) circuits is often deceptively complex. This paper uses the properties of sampled LPTV systems and the adjoint (inter-reciprocal) network to greatly simplify the analysis of the switched-RC circuit. We first derive the transfer function of the equivalent linear time-invariant filter relating the input to the voltage sampled on the capacitor in the switched-RC kernel. We show how a leakage resistor across the capacitor can be easily addressed using our technique. A signal-flow graph is then developed for the complete continuous-time voltage waveform across the capacitor, and simplified for various operating regions. We finally derive the noise properties of the kernel. The results we derive have largely been reported in prior works, but the use of the adjoint network simplifies the derivation, while also providing circuit insight.
Autors: Shanthi Pavan;Eric Klumperink;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Oct 2017, volume: 64, issue:10, pages: 2714 - 2725
Publisher: IEEE
 
» Simulation and Measurement of Through-the-Earth, Extremely Low-Frequency Signals Using Copper-Clad Steel Ground Rods
Abstract:
The underground mining environment can greatly affect radio signal propagation. Understanding how the earth affects signal propagation is a key to evaluating communications systems used during a mine emergency. One type of communication system is through-the-earth, which can utilize extremely low frequencies (ELF). This paper presents the simulation and measurement results of recent National Institute for Occupational Safety and Health (NIOSH) research aimed at investigating current injection at ELF, and in particular, ground contact impedance. Measurements were taken at an outside surface testing location. The results obtained from modeling and measurement are characterized by electrode impedance, and the voltage received between two distant electrodes. This paper concludes with a discussion of design considerations found to affect low-frequency communication systems utilizing ground rods to inject a current into the earth.
Autors: Nicholas William Damiano;Lincan Yan;Bruce Whisner;Chenming Zhou;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 5088 - 5095
Publisher: IEEE
 
» Simulation of a Large Power Brushless Synchronous Generator (BLSG) With a Rotating Rectifier by a Reluctance Network for Fault Analysis and Diagnosis
Abstract:
The aim of this paper is to simulate a large power brushless synchronous generator used for large turbo-alternator brushless excitation systems under conditions of saturation and rotating rectifier diode failures. A reluctance network coupled with electric circuits and power electronic components integrating the movement and nonlinearities of materials has been developed. The approach achieves good compromise between accuracy and computing time for the complete analysis of a 39 phase machine with 117 teeth and 22 poles, and 78 diodes in the associated rectifier bridge. Our model is validated by comparison with experimental measurements and numerical simulation by a finite element package. For the simulations presented, a gain in computation time of 800 can be obtained compared with a finite element model. Different results are calculated for healthy and faulty states to study the impact of open diode block failure. Simulation results show that open diode failures have little effect on the rectified output voltage, but the current through diodes and protection fuses increases. The currents in armature phase coil are very affected due to failures. A flux sensor coil can be placed on the stator pole to capture the impact of failures. The harmonic content of the pole flux can be used to monitor and detect diode failures.
Autors: Huu Kien Bui;Nicolas Bracikowski;Michel Hecquet;Kim-Lan Zappellini;Jean-Pierre Ducreux;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4327 - 4337
Publisher: IEEE
 
» Simulation Optimization for Medical Staff Configuration at Emergency Department in Hong Kong
Abstract:
Medical staff configuration is a critical problem in the management of an emergency department (ED) in Hong Kong (HK). Given the service requirements by HK government, it is imperative for the hospital managers to develop medical staff configuration in a cost-and-time-effective way. In this paper, the medical staff configuration problem in ED is modeled as minimizing the total labor cost while satisfying the service quality requirements. To solve this issue, we propose a highly efficient search method, called random boundary generation with feasibility detection (RBG-FD). The random boundary generation (RBG) is applied to efficiently identify good-quality solutions based on the objective value. The feasibility detection (FD) procedure is used to retain the probability of correct feasibility detection of each sampled solution at the desired level, which intrinsically allocates a reasonable number of simulation replications. To estimate the performance measures of the ED, a discrete-event simulation model is developed to reflect the patient flow. Using these techniques, the efficiency of identifying the optimal staff configuration can be significantly improved. A case study is performed in a public hospital in HK. The numerical results indicate significantly higher practicability and efficiency of the proposed method with different patient arrival rates and service constraints. Note to Practitioners This paper seeks to solve the problem of minimizing the medical staff cost constrained by certain service requirements [i.e., patients’ waiting times for treatment] at an emergency department in Hong Kong. In our formulation, these service requirements are characterized by some stochastic constraints. Most of the existing random search methods concentrate on the computing efforts in the neighborhood of the best-so-far solutions in order to obtain good-quality solutions. Due to the special structure of this problem and ease of computing - he objective values, we proposed an efficient random search approach that iteratively identifies a solution with a better objective value than that of the current best solution. Experimental studies demonstrate the significantly higher efficiency of this method. In order to obtain the same solution quality, it is able to reduce the computational time by 90% compared with some existing approaches in the literature.
Autors: Hainan Guo;Siyang Gao;Kwok-Leung Tsui;Tie Niu;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Oct 2017, volume: 14, issue:4, pages: 1655 - 1665
Publisher: IEEE
 
» Simulation-Based Study of Hybrid Fin/Planar LDMOS Design for FinFET-Based System-on-Chip Technology
Abstract:
A hybrid fin/planar lateral double-diffused MOSFET (LDMOS) design (hybrid FET) is proposed for the high-voltage input–output devices in a FinFET-based system-on-chip (SoC) technology. 3-D technology computer-aided design simulations show that a planar drift region and a planar drain region are advantageous for higher breakdown voltage (BV) to specific on-state resistance ( ratio (BV2/. By slightly extending the planar portion of the semiconductor active region into the gated channel region, the theoretical limit of BV2/ for LDMOS can be surpassed. Hybrid FETs can be fabricated using a process flow that is compatible with the state-of-art FinFET SoC technology.
Autors: Yi-Ting Wu;Fei Ding;Daniel Connelly;Peng Zheng;Meng-Hsueh Chiang;Jone F. Chen;Tsu-Jae King Liu;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4193 - 4199
Publisher: IEEE
 
» Simulations of the Interaction of High-Velocity Condensed-Matter Liners With Walls
Abstract:
This paper presents an overview of publications on numerical simulations of one of the major 2-D effects observed in magnetically driven implosion of cylindrical condensed-matter liners: their interaction with glide planes. We consider liners accelerated to 8–20 km/s by currents of 30–100 MA delivered by disk explosive magnetic flux compression generators with azimuthal magnetic fields of 1–6 MG (magnetic pressures of 0.04–1.4 Mbar): experimental liners HEL-1, ALT-1, 2, and liners HEL-2, ALT-3 proposed for high energy density physics research.
Autors: Anatoly M. Buyko;Sergey F. Garanin;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Oct 2017, volume: 45, issue:10, pages: 2701 - 2706
Publisher: IEEE
 
» Simultaneous Coherent and Random Noise Attenuation by Morphological Filtering With Dual-Directional Structuring Element
Abstract:
Seismic data are highly corrupted by noise or unwanted energies arising from different kinds of sources. In general, seismic noise can be divided into two categories, namely, coherent noise and random noise, and is treated with essentially different methods. Traditional methods often utilize the differences in frequency, wavenumber, or amplitude to separate signal and noise. However, the application of traditional methods is limited if the above-mentioned differences are too small to distinguish. For this reason, we have proposed a novel morphology-based technique to simultaneously attenuate random noise and coherent noise, i.e., to extract the useful signal. In this technique, we first flatten the signal by normal move out correction or other alternative approaches. For the extraction of the flatten reflections, we propose dual-directional mathematical morphological filtering, which can detect morphological information of the seismic waveforms from two orthogonal directions and then separate signal and other unwanted energy utilizing their difference in morphological scales. Application of the proposed technique on synthetic and field data examples demonstrates a successful performance.
Autors: Weilin Huang;Runqiu Wang;Yang Zhou;Xiaoqing Chen;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1720 - 1724
Publisher: IEEE
 
» Simultaneous Phase- and Frequency-Tunable Hybrid Coupler
Abstract:
The existing tunable circuits mainly concentrate on the control of frequency and amplitude. The control of phase characteristics becomes more and more important in the modern system for further performance enhancement. But none of existing coupler configurations can achieve this tunability. A novel hybrid coupler with simultaneous phase- and frequency-tunable characteristics is presented for the first time. Varying the difference between the capacitances for two rows of tunable capacitors loaded on the branch lines can provide different phase differences between two output ports with equal magnitude. Based on the same circuit, a tunable operating frequency can be realized while maintaining the equal power division and desired phase characteristics. This is achieved by simply changing the capacitances for two rows of tunable capacitors in unison. The high flexibility to achieve tunability in phase and frequency simultaneously is implemented. For demonstration purposes, a hybrid coupler operating at 1 GHz is designed and measured to validate the concept. It exhibits a variable phase difference from 45° to 135° while maintaining equal power division. Meanwhile, the same circuit gives a tunable operating frequency extending from 0.8 to 1.1 GHz while maintaining good performance for a 3 dB coupler with a tunable phase difference from 50° to 130°.
Autors: Shao Yong Zheng;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8088 - 8097
Publisher: IEEE
 
» Single Channel 50 Gbit/s Transmission Over 40 km SSMF Without Optical Amplification and In-Line Dispersion Compensation Using a Single-End PD-Based PDM-SSB-DMT System
Abstract:
We experimentally demonstrate a single-end photodetector (PD) based polarization-division-multiplexing (PDM) system, in which the single-sideband orthogonal frequency-division multiplexing (SSB-OFDM) and discrete multitone (DMT) signals are modulated on two orthogonal polarizations respectively. Based on the frequency interleave design for dual-polarization, the spectral efficiency and chromatic dispersion tolerance can be optimized. We derive the theoretical model for the PDM-SSB-DMT system and detail the digital signal processing for demultiplexing at the receiver. We also successfully transmit a 50 Gb/s PDM-SSB-DMT signal with 14 GHz bandwidth over 40 km of uncompensated and unamplified standard single mode fiber (SSMF) with only 1.1 dB power penalty for a bit error rate of 3.8 × 10–3 relative to back-to-back transmissions.
Autors: Xian Zhou;Jiahao Huo;Kangping Zhong;Faisal Nadeem Khan;Tao Gui;Hongyu Zhang;Jiajing Tu;Jinhui Yuan;Keping Long;Changyuan Yu;Alan Pak Tao Lau;Chao Lu;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 11
Publisher: IEEE
 
» Single Longitudinal Mode Optofluidic Microring Laser Based on a Hollow-Core Microstructured Optical Fiber
Abstract:
A single longitudinal mode microring dye laser based on a simplified hollow-core microstructured optical fiber (SHMOF) is proposed and demonstrated. The dye laser uses a submicron thickness silica microring embedded in the SHMOF as resonator and has the characteristic of a low threshold of 664 nJ/mm2. The factors that influence the single longitudinal mode excitation are discussed and the possible operation principle is analyzed. Meanwhile, the single longitudinal mode emissions at several different wavelengths are realized by using different dyes as gain medium, which indicates that the lasing wavelength of the laser is scalable. Time domain characteristics of the lasing are also measured and they are synchronous with the lateral pumping laser. The attractive possibility of developing microfluidic single longitudinal mode dye laser within the SHMOF presents opportunities for integrated optics applications and biomedical analysis with high sensitivity.
Autors: Jie Yu;Yange Liu;Mingming Luo;Zhi Wang;Guang Yang;Hongwei Zhang;Xiaohui Zhang;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 10
Publisher: IEEE
 

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