Electrical and Electronics Engineering publications abstract of: 06-2016 sorted by title, page: 0

» 1.55-μm Long-Wavelength VCSEL-Based Optical Interconnects for Short-Reach Networks
Abstract:
We demonstrate the generation and transmission of a 28-Gb/s intensity modulated optical signal over single mode fiber (SMF) links up to 1, 2, 5, and 10 km employing a 18-GHz 3-dB bandwidth monolithic vertical-cavity surface-emitting laser (VCSEL) based on buried tunnel junction technology with regrown n-doped InP material. Inexpensive technologies such as nonreturn-to-zero on–off keying modulation format, direct detection as well as digital signal processing-based receivers make the transmission feasible for chromatic dispersion (CD) uncompensated SMF links up to 10 km at the 7% hard-decision (HD) forward error correction (FEC) limit. Three different equalizers for the receiver side are investigated in this paper in terms of performance optimization, i.e., the maximum likelihood sequence estimation equalizer (MLSE), the feed-forward equalizer (FFE) and a hybrid scheme that comprises of an FFE and an MLSE equalizer (FFE/MLSE) in cascaded form. Our experimental results indicate that MLSE scheme outperforms the other two counterparts in all transmission scenarios. Performance optimization in terms of MLSE complexity is also presented. Less complex implementations like FFE equalizer can provide reliable transmission below the 7% HD-FEC limit for links up to 5 km. The FFE/MLSE scheme provides similar performance as MLSE for links up to 5 km, while its performance deteriorates for 10 and 15 km links as signal distortion due to CD becomes too severe to recover the signal. A timing recovery unit is employed before the equalizers in order to compensate for phase offsets and improve the signal quality. Our proposed scheme proves a promising candidate to enable VCSEL-based short reach optical interconnects in data centers and metro-access area.
Autors: Karinou, F.;Stojanovic, N.;Daly, A.;Neumeyr, C.;Ortsiefer, M.;
Appeared in: Journal of Lightwave Technology
Publication date: Jun 2016, volume: 34, issue:12, pages: 2897 - 2904
Publisher: IEEE
 
» 2-D Analytical Magnetic Field Prediction for Consequent-Pole Permanent Magnet Synchronous Machines
Abstract:
Consequent-pole permanent magnet (PM) synchronous machines (PMSMs) provide especial features by the use of alternate PM and ferromagnetic poles. The design of these types of electric machines requires an accurate model due to the asymmetrical flux distribution in the air gap under adjacent poles. The equivalent magnetic circuit technique can hardly offer an accurate model for consequent-pole PMSMs. To this end, a 2-D analytical model is presented for consequent-pole slotted stator PMSMs to accurately compute the magnetic field distribution due to PMs and armature reaction. The slotting effects and the tooth-tip effects are taken into consideration by using the subdomain technique. The proposed model is used to calculate the magnetic flux density distributions of three consequent-pole PMSMs: an 8-pole, 9-slot machine with a non-overlapping winding; a 4-pole, 15-slot machine with an overlapping winding; and a 10-pole, 12-slot machine with a non-overlapping winding, each with three different magnetization patterns, i.e., radial, parallel, and Halbach. Based on the magnetic flux distribution, the electromagnetic torque, the self- and mutual-inductances, and the unbalanced magnetic forces have been analytically calculated. The analytical results are compared with those obtained from the finite-element method to show the accuracy and efficacy of the proposed 2-D analytical model.
Autors: Teymoori, S.;Rahideh, A.;Moayed Jahromi, H.;Mardaneh, M.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jun 2016, volume: 52, issue:6, pages: 1 - 14
Publisher: IEEE
 
» 2-D Analytical Subdomain Model for Hybrid Dual-Rotor Motor
Abstract:
Recently, dual-rotor motor (DRM) has emerged as an alternative for an induction motor (IM) or a permanent-magnet (PM) motor for electric vehicle application, due to its better drive performance and better torque density. This paper presents an analytical model for the hybrid IM-PM configuration of DRM. The analytical model can be used to predict induced bar currents, electromagnetic torque generated, and magnetic fields in various regions of the motor. The mentioned calculations are performed under steady-state conditions. The analytical method is developed using the subdomain model approach in 2-D polar coordinates. Appropriate governing equations along with boundary conditions across all the sub-domain regions of the DRM are employed to calculate the magnetic vector potential in all the regions. The developed analytical model has been validated with finite-element analysis for various operating conditions, and high accuracy has been achieved for all the results.
Autors: Dalal, A.;Nekkalapu, S.;Kumar, P.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jun 2016, volume: 52, issue:6, pages: 1 - 9
Publisher: IEEE
 
» 25 Gb/s Silicon Photonics Interconnect Using a Transmitter Based on a Node-Matched-Diode Modulator
Abstract:
In this article a nonreturn-to-zero data transmission of 25 Gb/s between silicon photonic transmitter and receiver units is demonstrated, where the transmitter is based on a silicon optical Fabry–Pérot modulator with a node-matched-diode geometry. This modulator type has a footprint of less than 100 μm2. On the receiver side, an integrated Ge-photo detector has been used. Mask tests according to the 100G ER4 standard have been performed and yielded error free data transmission.
Autors: Kupijai, S.;Rhee, H.;Al-Saadi, A.;Henniges, M.;Bronzi, D.;Selicke, D.;Theiss, C.;Otte, S.;Eichler, H.J.;Woggon, U.;Stolarek, D.;Richter, H.H.;Zimmermann, L.;Tillack, B.;Meister, S.;
Appeared in: Journal of Lightwave Technology
Publication date: Jun 2016, volume: 34, issue:12, pages: 2920 - 2923
Publisher: IEEE
 
» 25-Gb/s Operation of a Polymer Optical Waveguide on an Electrical Hybrid LSI Package Substrate With Optical Card Edge Connector
Abstract:
We propose a high-capacity polymer-based optical and electrical LSI package integrated with multimode Si photonic transmitters and receivers. We describe the fabrication and characteristics of the polymer-based hybrid LSI package substrate with a polymer optical waveguide, a mirror, and optical card edge connectors. We fabricated optical mirrors with several angles ranging from 40° to 45° for the Si photonic grating coupler by using a dicing blade at an angle. The dicing mirror changed the emission angle for the grating coupler. We also realized a large lateral misalignment tolerance (±11.5 μm) between the polymer waveguide and MMF for 1 dB of excess loss at 24 channels. We obtained 1-dB coupling loss using an optical card edge connector at 1.3 μm because of the large tolerance. We realized 25-Gb/s error-free transmission per channel at 1.3 μm. We also describe here the error penalty and jitter due to modal noise generated by coupling mismatch.
Autors: Amano, T.;Ukita, S.;Egashira, Y.;Sasaki, M.;Noriki, A.;Mori, M.;Kurata, K.;Sakakibara, Y.;
Appeared in: Journal of Lightwave Technology
Publication date: Jun 2016, volume: 34, issue:12, pages: 3006 - 3011
Publisher: IEEE
 
» 3D Fast Automatic Segmentation of Kidney Based on Modified AAM and Random Forest
Abstract:
In this paper, a fully automatic method is proposed to segment the kidney into multiple components: renal cortex, renal column, renal medulla and renal pelvis, in clinical 3D CT abdominal images. The proposed fast automatic segmentation method of kidney consists of two main parts: localization of renal cortex and segmentation of kidney components. In the localization of renal cortex phase, a method which fully combines 3D Generalized Hough Transform (GHT) and 3D Active Appearance Models (AAM) is applied to localize the renal cortex. In the segmentation of kidney components phase, a modified Random Forests (RF) method is proposed to segment the kidney into four components based on the result from localization phase. During the implementation, a multithreading technology is applied to speed up the segmentation process. The proposed method was evaluated on a clinical abdomen CT data set, including 37 contrast-enhanced volume data using leave-one-out strategy. The overall true-positive volume fraction and false-positive volume fraction were 93.15%, 0.37% for renal cortex segmentation; 83.09%, 0.97% for renal column segmentation; 81.92%, 0.55% for renal medulla segmentation; and 80.28%, 0.30% for renal pelvis segmentation, respectively. The average computational time of segmenting kidney into four components took 20 seconds.
Autors: Chao, J.;Shi, F.;Xiang, D.;Xueqing, J.;Zhang, B.;Wang, X.;Zhu, W.;Gao, E.;Chen, X.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jun 2016, volume: 35, issue:6, pages: 1395 - 1407
Publisher: IEEE
 
» 3D Quantification of Wall Shear Stress and Oscillatory Shear Index Using a Finite-Element Method in 3D CINE PC-MRI Data of the Thoracic Aorta
Abstract:
Several 2D methods have been proposed to estimate WSS and OSI from PC-MRI, neglecting the longitudinal velocity gradients that typically arise in cardiovascular flow, particularly on vessel geometries whose cross section and centerline orientation strongly vary in the axial direction. Thus, the contribution of longitudinal velocity gradients remains understudied. In this work, we propose a 3D finite-element method for the quantification of WSS and OSI from 3D-CINE PC-MRI that accounts for both in-plane and longitudinal velocity gradients. We demonstrate the convergence and robustness of the method on cylindrical geometries using a synthetic phantom based on the Poiseuille flow equation. We also show that, in the presence of noise, the method is both stable and accurate. Using computational fluid dynamics simulations, we show that the proposed 3D method results in more accurate WSS estimates than those obtained from a 2D analysis not considering out-of-plane velocity gradients. Further, we conclude that for irregular geometries the accurate prediction of WSS requires the consideration of longitudinal gradients in the velocity field. Additionally, we compute 3D maps of WSS and OSI for 3D-CINE PC-MRI data sets from an aortic phantom and sixteen healthy volunteers and two patients. The OSI values show a greater dispersion than WSS, which is strongly dependent on the PC-MRI resolution. We envision that the proposed 3D method will improve the estimation of WSS and OSI from 3D-CINE PC-MRI images, allowing for more accurate estimates in vessels with pathologies that induce high longitudinal velocity gradients, such as coarctations and aneurisms.
Autors: Sotelo, J.;Urbina, J.;Valverde, I.;Tejos, C.;Irarrazaval, P.;Andia, M.E.;Uribe, S.;Hurtado, D.E.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jun 2016, volume: 35, issue:6, pages: 1475 - 1487
Publisher: IEEE
 
» Observer Design for LPV Systems With Uncertain Measurements on Scheduling Variables: Application to an Electric Ground Vehicle
Abstract:
In this paper, we aim to study the observer design problem for polytopic linear-parameter-varying (LPV) systems with uncertain measurements on scheduling variables. Due to the uncertain measurements, the uncertainties are considered in the weighting factors. It is assumed that the vertices of polytope are the same when the measurements on scheduling variables are uncertain and perfect. Then, an LPV system with the uncertain weighting factors can be transferred to an LPV system with uncertainties. To deal with the uncertainties and unknown disturbance in the observer design problem, we propose a gain-scheduling sliding mode observer. Defining the estimation error as the state vector minus the estimated state vector, the estimation error dynamics is established. The sliding mode observer design method is developed based on analysis results of the established estimation error system. The proposed observer design method is then applied to an electric ground vehicle (EGV) in which the measurement of longitudinal velocity is assumed to be uncertain. Experimental tests and comparisons are given to show the advantages of the proposed design method and the designed observer.
Autors: Zhang, H.;Zhang, G.;Wang, J.;
Appeared in: IEEE/ASME Transactions on Mechatronics
Publication date: Jun 2016, volume: 21, issue:3, pages: 1659 - 1670
Publisher: IEEE
 
» -Inductive Property of Sequential Circuits
Abstract:
This paper introduces -inductiveness over a set of nodes in sequential circuits. The -inductive property can be used for equivalence-checking or improved sequential optimization. It allows the behavior of many next state functions (not in ) to be changed while maintaining correctness at the primary outputs of a circuit. As such, it creates flexibility that can be used for sequential optimization. It is shown that the number of nodes in is reduced as m, the parameter for the inductiveness, increases. We provide an algorithm for finding a minimal set , as well as one for using -inductiveness in optimization. We give examples of such optimized circuits and show that -inductive-based optimization can result in significant area reduction when applied to industrial designs.
Autors: Savoj, H.;Mishchenko, A.;Brayton, R.;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jun 2016, volume: 35, issue:6, pages: 919 - 930
Publisher: IEEE
 
» Observer Design for LPV Systems With Uncertain Measurements on Scheduling Variables: Application to an Electric Ground Vehicle
Abstract:
In this paper, we aim to study the observer design problem for polytopic linear-parameter-varying (LPV) systems with uncertain measurements on scheduling variables. Due to the uncertain measurements, the uncertainties are considered in the weighting factors. It is assumed that the vertices of polytope are the same when the measurements on scheduling variables are uncertain and perfect. Then, an LPV system with the uncertain weighting factors can be transferred to an LPV system with uncertainties. To deal with the uncertainties and unknown disturbance in the observer design problem, we propose a gain-scheduling sliding mode observer. Defining the estimation error as the state vector minus the estimated state vector, the estimation error dynamics is established. The sliding mode observer design method is developed based on analysis results of the established estimation error system. The proposed observer design method is then applied to an electric ground vehicle (EGV) in which the measurement of longitudinal velocity is assumed to be uncertain. Experimental tests and comparisons are given to show the advantages of the proposed design method and the designed observer.
Autors: Zhang, H.;Zhang, G.;Wang, J.;
Appeared in: IEEE/ASME Transactions on Mechatronics
Publication date: Jun 2016, volume: 21, issue:3, pages: 1659 - 1670
Publisher: IEEE
 
» pd-gem5: Simulation Infrastructure for Parallel/Distributed Computer Systems
Abstract:
Improving the performance and power efficiency of a single processor has been fraught with various challenges stemming from the end of the classical technology scaling. Thus, the importance of efficiently running applications on a parallel/distributed computer system has continued to increase. In developing and optimizing such a parallel/distributed computer system, it is critical to study the impact of the complex interplay amongst processor, node, and network architectures on performance and power efficiency in detail. This necessitates a flexible, detailed and open-source full-system simulation infrastructure. However, our community lacks such an infrastructure. In this paper, we present pd-gem5, a gem5-based infrastructure that can model and simulate a parallel/distributed computer system using multiple simulation hosts. Our experiment shows that pd-gem5 running on six simulation hosts speeds up the simulation of a 24-node computer system up to 3.2× compared with running on a single simulation host.
Autors: Alian, M.;Kim, D.;Kim, N.S.;
Appeared in: Computer Architecture Letters
Publication date: Jun 2016, volume: 15, issue:1, pages: 41 - 44
Publisher: IEEE
 
» qcAffin: A Hardware Topology Aware Interrupt Affinitizing and Balancing Scheme for Multi-Core and Multi-Queue Packet Processing Systems
Abstract:
Interrupt affinitization of multi-queue network interface cards is a fundamental composition that defines how packets from individual queue are processed by which CPU-cores on multi-core platforms. In this paper, we propose qcAffin to attain an optimal queue-to-core affinitization for packet processing systems based on a numerical cost model derived from hardware topology and runtime system workloads. Static architectural characteristics comprising the memory hierarchy and topology of hardware components are first analyzed to calculate static interrupt affinitization costs. Then we attempt dynamic interrupt affinitization to balance workloads on CPU-cores and improve overall performance. Classical networking applications ranging from bridging, routing, access control list (ACL) matching to deep packet inspection (DPI) with different frame sizes are extensively experimented to compare the performance of the proposed scheme and other existing approaches. As demonstrated in the comparison result, qcAffin achieves the similar performance of the best affinitization approach and outperforms the Linux default affinitizer by averages of 102, 278, 248 and 131 percent on 1G NICs for the four applications. On 10G NICs, dramatic boosts of 1,424 and 1,343 percent are measured for the bridging and routing applications, respectively. Moreover, the effectiveness of dynamic interrupt balancing is justified by a maximum of 150 percent higher system utilization and 1.2 Mpps more throughput compared to the fixed affinitization approach in a simulated setup of unbalanced traffic load.
Autors: Huang, Nen-Fu;Tsai, Wen-Yen;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jun 2016, volume: 27, issue:6, pages: 1783 - 1795
Publisher: IEEE
 
» ToothPIC: An Interactive Application for Teaching Oral Anatomy
Abstract:
This paper describes the development and evaluation of an interactive educational program, Tooth Placement and Identification Coach (ToothPIC). The program uses a game-based learning paradigm and 3D visualization techniques to allow first year dentistry and hygiene students to get familiar with dental anatomy. It provides an interactive and stimulating learning tool for acquiring basic dental skills outside of the classroom. Specifically, it uses interactive 3D graphics to teach students to identify, name, number, align, and orient teeth into their proper location in the dental arch. ToothPIC incorporates elements of a game to make learning attractive for the student. In the process, the student learns not only about the 3D features of each tooth but also about the proper placement of the tooth relative to the gingiva and other teeth. ToothPIC has two modules: Module 1 includes 32 permanent upper and lower teeth that are to be identified and placed into the surrounding gingiva. Module 2 only shows the individual teeth, one at a time, to be identified (similar to a “flash-card”). The evaluation results of ToothPIC indicate that students strongly agree that program meets its goals of self-training and self-evaluation, actively involves the students in learning and is a useful supplement to laboratory practices and lectures.
Autors: Javaid, M.;Ashrafi, S.;Zefran, M.;Steinberg, A.D.;
Appeared in: IEEE Transactions on Learning Technologies
Publication date: Jun 2016, volume: 9, issue:2, pages: 184 - 189
Publisher: IEEE
 
» Heads-Join: Efficient Earth Mover's Distance Similarity Joins on Hadoop
Abstract:
The Earth Mover's Distance (EMD) similarity join has a number of important applications such as near duplicate image retrieval and distributed based pattern analysis. However, the computational cost of EMD is super cubic and consequently the EMD similarity join operation is prohibitive for datasets of even medium size. We propose to employ the Hadoop platform to speed up the operation. Simply porting the state-of-the-art metric distance similarity join algorithms to Hadoop results in inefficiency because they involve excessive distance computations and are vulnerable to skewed data distributions. We propose a novel framework, named Heads-Join, which transforms data into the space of EMD lower bounds and performs pruning and partitioning at a low cost because computing these EMD lower bounds has constant or linear complexity. We investigate both range and top- joins, and design efficient algorithms on three popular Hadoop computation paradigms, i.e., MapReduce, Bulk Synchronous Parallel, and Spark. We conduct extensive experiments on both real and synthetic datasets. The results show that Heads-Join outperforms the state-of-the-art metric similarity join technique, i.e., Quickjoin, by up to an order of magnitude and scales out well.
Autors: Huang, J.;Zhang, R.;Buyya, R.;chen, J.;Wu, Y.;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jun 2016, volume: 27, issue:6, pages: 1660 - 1673
Publisher: IEEE
 
» A 0.04 mm Buck-Boost DC-DC Converter for Biomedical Implants Using Adaptive Gain and Discrete Frequency Scaling Control
Abstract:
This paper presents the design of a reconfigurable buck-boost switched-capacitor DC-DC converter suitable for use in a wide range of biomedical implants. The proposed converter has an extremely small footprint and uses a novel control method that allows coarse and fine control of the output voltage. The converter uses adaptive gain control, discrete frequency scaling and pulse-skipping schemes to regulate the power delivered to a range of output voltages and loads. Adaptive gain control is used to implement variable switching gain ratios from a reconfigurable power stage and thereby make coarse steps in output voltage. A discrete frequency scaling controller makes discrete changes in switching frequency to vary the power delivered to the load and perform fine tuning when the output voltage is within 10% of the target output voltage. The control architecture is predominately digital and it has been implemented as part of a fully-integrated switched-capacitor converter design using a standard bulk CMOS 0.18 μm process. Measured results show that the converter has an output voltage range of 1.0 to 2.2 V, can deliver up to 7.5 mW of load power and efficiency up to 75% using an active area of only 0.04 mm2, which is significantly smaller than that of other designs. This low-area, low-complexity reconfigurable power converter can support low-power circuits in biomedical implant applications.
Autors: George, L.;Gargiulo, G.D.;Lehmann, T.;Hamilton, T.J.;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Jun 2016, volume: 10, issue:3, pages: 668 - 678
Publisher: IEEE
 
» A 0.5-V 1.3- Analog Front-End CMOS Circuit
Abstract:
This brief presents a low-power analog acquisition front-end circuit for a Wireless Body Area Network. This front-end system mainly consists of three parts, namely, chopped capacitively coupled instrumentation amplifier (CCIA), switched capacitor filter (SC-filter), and successive-approximation analog-to-digital converter. In order to reduce the power consumption, the supply voltage is scaled to 0.5 V, and all analog building blocks are biased in the subthreshold region. The chopper-stabilized technique is introduced to eliminate the noise, and a dc-servo loop is employed in the CCIA to suppress the electrode offset. A low-power second-order SC-filter is employed to eliminate the spikes produced by the CCIA, which also realizes a tunable gain to satisfy the specification. This low-power analog front-end circuit has been fabricated in a 0.18- CMOS process. It occupies 1 mm2 and consumes a minimal 1.3 at 0.5 V. It achieves a bandwidth of 0.5–250 Hz, a CMRR of 95 dB, and an input impedance of 48 , respectively.
Autors: Zhu, Z.;Bai, W.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jun 2016, volume: 63, issue:6, pages: 523 - 527
Publisher: IEEE
 
» A 0.5-V 1.3- Analog Front-End CMOS Circuit
Abstract:
This brief presents a low-power analog acquisition front-end circuit for a Wireless Body Area Network. This front-end system mainly consists of three parts, namely, chopped capacitively coupled instrumentation amplifier (CCIA), switched capacitor filter (SC-filter), and successive-approximation analog-to-digital converter. In order to reduce the power consumption, the supply voltage is scaled to 0.5 V, and all analog building blocks are biased in the subthreshold region. The chopper-stabilized technique is introduced to eliminate the noise, and a dc-servo loop is employed in the CCIA to suppress the electrode offset. A low-power second-order SC-filter is employed to eliminate the spikes produced by the CCIA, which also realizes a tunable gain to satisfy the specification. This low-power analog front-end circuit has been fabricated in a 0.18- CMOS process. It occupies 1 mm2 and consumes a minimal 1.3 at 0.5 V. It achieves a bandwidth of 0.5–250 Hz, a CMRR of 95 dB, and an input impedance of 48 , respectively.
Autors: Zhu, Z.;Bai, W.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jun 2016, volume: 63, issue:6, pages: 523 - 527
Publisher: IEEE
 
» A 128-Channel Extreme Learning Machine-Based Neural Decoder for Brain Machine Interfaces
Abstract:
Currently, state-of-the-art motor intention decoding algorithms in brain-machine interfaces are mostly implemented on a PC and consume significant amount of power. A machine learning coprocessor in 0.35- μm CMOS for the motor intention decoding in the brain-machine interfaces is presented in this paper. Using Extreme Learning Machine algorithm and low-power analog processing, it achieves an energy efficiency of 3.45 pJ/MAC at a classification rate of 50 Hz. The learning in second stage and corresponding digitally stored coefficients are used to increase robustness of the core analog processor. The chip is verified with neural data recorded in monkey finger movements experiment, achieving a decoding accuracy of 99.3% for movement type. The same coprocessor is also used to decode time of movement from asynchronous neural spikes. With time-delayed feature dimension enhancement, the classification accuracy can be increased by 5% with limited number of input channels. Further, a sparsity promoting training scheme enables reduction of number of programmable weights by ≈ 2X.
Autors: Chen, Y.;Yao, E.;Basu, A.;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Jun 2016, volume: 10, issue:3, pages: 679 - 692
Publisher: IEEE
 
» A 200-Channel Area-Power-Efficient Chemical and Electrical Dual-Mode Acquisition IC for the Study of Neurodegenerative Diseases
Abstract:
Microelectrode array (MEA) can be used in the study of neurodegenerative diseases by monitoring the chemical neurotransmitter release and the electrical potential simultaneously at the cellular level. Currently, the MEA technology is migrating to more electrodes and higher electrode density, which raises power and area constraints on the design of acquisition IC. In this paper, we report the design of a 200-channel dual-mode acquisition IC with highly efficient usage of power and area. Under the constraints of target noise and fast settling, the current channel design saves power by including a novel current buffer biased in discrete time (DT) before the TIA (transimpedance amplifier). The 200 channels are sampled at 20 kS/s and quantized by column-wise SAR ADCs. The prototype IC was fabricated in a 0.18 μm CMOS process. Silicon measurements show the current channel has 21.6 pArms noise with cyclic voltammetry (CV) and 0.48 pArms noise with constant amperometry (CA) while consuming 12.1 μW. The voltage channel has 4.07 μVrms noise in the bandwidth of 100 kHz and 0.2% nonlinearity while consuming 9.1 μW. Each channel occupies 0.03 mm2 area, which is among the smallest.
Autors: Guo, J.;Ng, W.;Yuan, J.;Li, S.;Chan, M.;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Jun 2016, volume: 10, issue:3, pages: 567 - 578
Publisher: IEEE
 
» A 25 Gb/s 3D-Integrated CMOS/Silicon-Photonic Receiver for Low-Power High-Sensitivity Optical Communication
Abstract:
Integrating optical receivers based on double-sampling architecture exhibit a low-power alternative to those designed around transimpedance amplifiers (TIA). In this paper, we present a 3D-integrated CMOS/silicon-photonic optical receiver. The receiver features a low-bandwidth TIA integrating front-end double-sampling technique and dynamic offset modulation. The copper-pillar-based 3D-integration technology used here enables ultralow parasitics and 40 μm pitch for interconnection. We study different tradeoffs in designing an optical receiver and how to choose between a full-bandwidth TIA front-end and integrating architecture using a resistive front-end or a low-bandwidth TIA front-end. The design methodology is supported by measurements of two 3D-integrated prototypes based on a conventional TIA and a double-sampling integrating receiver. The proposed receiver architecture achieves −14.9 dBm of sensitivity and energy efficiency of 170 fJ/b at 25 Gb/s, while the conventional receiver achieves a sensitivity of −10.4 dBm and energy efficiency of 260 fJ/b at 21.2 Gb/s.
Autors: Saeedi, S.;Menezo, S.;Pares, G.;Emami, A.;
Appeared in: Journal of Lightwave Technology
Publication date: Jun 2016, volume: 34, issue:12, pages: 2924 - 2933
Publisher: IEEE
 
» A 25-Gb/s 5 × 5 mm2 Chip-Scale Silicon-Photonic Receiver Integrated With 28-nm CMOS Transimpedance Amplifier
Abstract:
We have developed a 5 × 5 mm2 compact silicon-photonic receiver with a 28-nm CMOS transimpedance-amplifier (TIA) chip. The receiver chip was designed using a photonics—electronics convergence design technique for the realization of high-speed and high-efficiency operation because the interfaces of the optical and electrical components greatly influence the receiver characteristics. Optical pins were used to obtain easy optical alignment between the multimode fibers and the germanium photodetectors. An aluminum stripline between the PD and the TIA enhanced the 3-dB bandwidth because its characteristic impedance is greater than the TIA input impedance. Coplanar waveguides (CPWs) on the etched SOI wafer achieved a low insertion loss because the overlap between the electric fields of the CPWs and the silicon layer was reduced. We demonstrated 25-Gb/s error-free operation at both 25 and at 85 °C. The minimum sensitivities and power consumptions of the receivers were −11.0 dBm and 2.3 mW/Gb/s at 25 °C and −10.2 dBm and 2.5 mW/Gb/s at 85 °C, respectively. These results show that our receiver can be applied for practical use at high temperatures.
Autors: Okamoto, D.;Suzuki, Y.;Yashiki, K.;Hagihara, Y.;Tokushima, M.;Fujikata, J.;Kurihara, M.;Tsuchida, J.;Nedachi, T.;Inasaka, J.;Kurata, K.;
Appeared in: Journal of Lightwave Technology
Publication date: Jun 2016, volume: 34, issue:12, pages: 2988 - 2995
Publisher: IEEE
 
» A 64-Channel 965- Neural Recording SoC With UWB Wireless Transmission in 130-nm CMOS
Abstract:
This brief presents a 64-channel neural recording system-on-chip (SoC) with a 20-Mb/s wireless telemetry. Each channel of the analog front end consists of a low-noise bandpass amplifier, featuring a noise efficiency factor of 3.11 with an input-referred noise of 5.6 μVrms in a 0.001- to 10-kHz band and a 31.25-kSps 6-fJ/conversion-step 10-bit SAR analog-to-digital converter. The recorded signals are multiplexed in the digital domain and transmitted via an 11.7% efficiency pulse-position modulation ultrawideband transmitter, reaching a transmission range in excess of 7.5 m. The chip has been fabricated in a 130-nm CMOS process, measures 25 mm2, and dissipates 965 μW from a 0.5-V supply. This SoC features the lowest power per channel (15 μW) and the lowest energy per bit (48.2 pJ) among state-of-the-art wireless neural recording systems with a number of channels larger than 32. The proposed circuit is able to transmit the raw neural signal in a large bandwidth (up to 10 kHz) without performing any data compression or losing vital information, such as local field potentials.
Autors: Brenna, S.;Padovan, F.;Neviani, A.;Bevilacqua, A.;Bonfanti, A.;Leonardo Lacaita, A.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jun 2016, volume: 63, issue:6, pages: 528 - 532
Publisher: IEEE
 
» A 64-Channel 965- Neural Recording SoC With UWB Wireless Transmission in 130-nm CMOS
Abstract:
This brief presents a 64-channel neural recording system-on-chip (SoC) with a 20-Mb/s wireless telemetry. Each channel of the analog front end consists of a low-noise bandpass amplifier, featuring a noise efficiency factor of 3.11 with an input-referred noise of 5.6 in a 0.001- to 10-kHz band and a 31.25-kSps 6-fJ/conversion-step 10-bit SAR analog-to-digital converter. The recorded signals are multiplexed in the digital domain and transmitted via an 11.7% efficiency pulse-position modulation ultrawideband transmitter, reaching a transmission range in excess of 7.5 m. The chip has been fabricated in a 130-nm CMOS process, measures 25 mm2, and dissipates 965 from a 0.5-V supply. This SoC features the lowest power per channel (15 ) and the lowest energy per bit (48.2 pJ) among state-of-the-art wireless neural recording systems with a number of channels larger than 32. The proposed circuit is able to transmit the raw neural signal in a large bandwidth (up to 10 kHz) without performing any data compression or losing vital information, such as local field potentials.
Autors: Brenna, S.;Padovan, F.;Neviani, A.;Bevilacqua, A.;Bonfanti, A.;Leonardo Lacaita, A.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jun 2016, volume: 63, issue:6, pages: 528 - 532
Publisher: IEEE
 
» A -Gb/s Referenceless-and-Masterless Phase Rotator-Based Parallel Transceiver in 90-nm CMOS
Abstract:
A four-parallel 10-Gb/s referenceless-and-masterless phase rotator-based transceiver is presented. Entire lanes operate independently just like the conventional voltage-controlled-oscillator-based parallel referenceless designs while saving power and area. The measured recovered-clock jitter in each lane is 1.24 psrms and the transceiver surpasses the OC-192 jitter-tolerance specification. The power efficiency of the proposed parallel transceiver fabricated in a 90-nm CMOS process is 6.325 mW/(Gb/s).
Autors: Lee, J.-Y.;Yang, J.;Yoon, J.-H.;Kwon, S.-W.;Won, H.;Han, J.;Bae, H.-M.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jun 2016, volume: 24, issue:6, pages: 2310 - 2320
Publisher: IEEE
 
» A -Gb/s Referenceless-and-Masterless Phase Rotator-Based Parallel Transceiver in 90-nm CMOS
Abstract:
A four-parallel 10-Gb/s referenceless-and-masterless phase rotator-based transceiver is presented. Entire lanes operate independently just like the conventional voltage-controlled-oscillator-based parallel referenceless designs while saving power and area. The measured recovered-clock jitter in each lane is 1.24 psrms and the transceiver surpasses the OC-192 jitter-tolerance specification. The power efficiency of the proposed parallel transceiver fabricated in a 90-nm CMOS process is 6.325 mW/(Gb/s).
Autors: Lee, J.-Y.;Yang, J.;Yoon, J.-H.;Kwon, S.-W.;Won, H.;Han, J.;Bae, H.-M.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jun 2016, volume: 24, issue:6, pages: 2310 - 2320
Publisher: IEEE
 
» A Batteryless Sensor ASIC for Implantable Bio-Impedance Applications
Abstract:
The measurement of the biological tissue's electrical impedance is an active research field that has attracted a lot of attention during the last decades. Bio-impedances are closely related to a large variety of physiological conditions; therefore, they are useful for diagnosis and monitoring in many medical applications. Measuring living tissues, however, is a challenging task that poses countless technical and practical problems, in particular if the tissues need to be measured under the skin. This paper presents a bio-impedance sensor ASIC targeting a battery-free, miniature size, implantable device, which performs accurate 4-point complex impedance extraction in the frequency range from 2 kHz to 2 MHz. The ASIC is fabricated in 150 nm CMOS, has a size of 1.22 mm × 1.22 mm and consumes 165 μA from a 1.8 V power supply. The ASIC is embedded in a prototype which communicates with, and is powered by an external reader device through inductive coupling. The prototype is validated by measuring the impedances of different combinations of discrete components, measuring the electrochemical impedance of physiological solution, and performing ex vivo measurements on animal organs. The proposed ASIC is able to extract complex impedances with around 1 Ω resolution; therefore enabling accurate wireless tissue measurements.
Autors: Rodriguez, S.;Ollmar, S.;Waqar, M.;Rusu, A.;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Jun 2016, volume: 10, issue:3, pages: 533 - 544
Publisher: IEEE
 
» A Bayesian Classification Approach Using Class-Specific Features for Text Categorization
Abstract:
In this paper, we present a Bayesian classification approach for automatic text categorization using class-specific features. Unlike conventional text categorization approaches, our proposed method selects a specific feature subset for each class. To apply these class-specific features for classification, we follow Baggenstoss's PDF Projection Theorem (PPT) to reconstruct the PDFs in raw data space from the class-specific PDFs in low-dimensional feature subspace, and build a Bayesian classification rule. One noticeable significance of our approach is that most feature selection criteria, such as Information Gain (IG) and Maximum Discrimination (MD), can be easily incorporated into our approach. We evaluate our method's classification performance on several real-world benchmarks, compared with the state-of-the-art feature selection approaches. The superior results demonstrate the effectiveness of the proposed approach and further indicate its wide potential applications in data mining.
Autors: Tang, B.;He, H.;Baggenstoss, P.M.;Kay, S.;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Jun 2016, volume: 28, issue:6, pages: 1602 - 1606
Publisher: IEEE
 
» A Bayesian Ensemble Regression Framework on the Angry Birds Game
Abstract:
In this paper, we introduce AngryBER, an intelligent agent architecture on the Angry Birds domain that employs a Bayesian ensemble inference mechanism to promote decision-making abilities. It is based on an efficient tree-like structure for encoding and representing game screenshots, where it exploits its enhanced modeling capabilities. This has the advantage to establish an informative feature space and translate the task of game playing into a regression analysis problem. A Bayesian ensemble regression framework is presented by considering that every combination of objects’ material and bird type has its own regression model. We address the problem of action selection as a multiarmed bandit problem, where the upper confidence bound (UCB) strategy has been used. An efficient online learning procedure has been also developed for training the regression models. We have evaluated the proposed methodology on several game levels, and compared its performance with published results of all agents that participated in the 2013 and 2014 Angry Birds AI competitions. The superiority of the new method is readily deduced by inspecting the reported results.
Autors: Tziortziotis, N.;Papagiannis, G.;Blekas, K.;
Appeared in: IEEE Transactions on Computational Intelligence and AI in Games
Publication date: Jun 2016, volume: 8, issue:2, pages: 104 - 115
Publisher: IEEE
 
» A Bidirectional Boost Converter With Application to a Regenerative Suspension System
Abstract:
This paper proposes an algorithm to control the suspension dynamics with an energy regeneration capability and high conversion efficiency. Central to the concept is the development of a switched-mode rectifier (SMR) that is capable of providing either an equivalent positive or negative damping and alternating between regenerative and motoring modes. Simulation results are presented to demonstrate power flow in regeneration and motoring modes and verify the equivalent damping characteristic and vibration energy harvesting. The studies are conducted on a small-scale proof-of-concept electromagnetic suspension system excited by emulated International Standard Organization (ISO) 8608 road profiles. An autonomous start/stop algorithm is proposed such that autonomously turns on or off the converter. This mechanism mitigates quiescent power consumption of auxiliary integrated circuits (ICs) such as gate drivers and current transducers, therefore increasing the conversion efficiency of the power electronics throughout an ISO standardized variable-speed driving cycle. The autonomous start/stop algorithm is implemented experimentally to demonstrate its feasibility under typical standardized driving cycles.
Autors: Hsieh, C.-Y.;Moallem, M.;Golnaraghi, F.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jun 2016, volume: 65, issue:6, pages: 4301 - 4311
Publisher: IEEE
 
» A Circuit Model of Real Time Human Body Hydration
Abstract:
Changes in human body hydration leading to excess fluid losses or overload affects the body fluid's ability to provide the necessary support for healthy living. We propose a time-dependent circuit model of real-time human body hydration, which models the human body tissue as a signal transmission medium. The circuit model predicts the attenuation of a propagating electrical signal. Hydration rates are modeled by a time constant , which characterizes the individual specific metabolic function of the body part measured. We define a surrogate human body anthropometric parameter by the muscle–fat ratio and comparing it with the body mass index (BMI), we find theoretically, the rate of hydration varying from 1.73 dB/min, for high and low to 0.05 dB/min for low and high . We compare these theoretical values with empirical measurements and show that real-time changes in human body hydration can be observed by measuring signal attenuation. We took empirical measurements using a vector network analyzer and obtained different hydration rates for various BMI, ranging from 0.6 dB/min for 22.7 down to 0.04 dB/min for 41.2 . We conclude that the galvanic coupling circuit model can predict changes in the volume of the body fluid, which are essential in diagnosing and monitoring treatment of body fluid disorder. Individuals wit- high BMI would have higher time-dependent biological characteristic, lower metabolic rate, and lower rate of hydration.
Autors: Asogwa, C.O.;Teshome, A.K.;Collins, S.F.;Lai, D.T.H.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jun 2016, volume: 63, issue:6, pages: 1239 - 1247
Publisher: IEEE
 
» A Classification Approach for Model-Based Fault Diagnosis in Power Generation Systems Based on Solid Oxide Fuel Cells
Abstract:
Solid oxide fuel cells (SOFCs) are a promising option for power generation plants, but the design of fault diagnosis methods remains a key challenge. We propose the use of a quantitative model for such a plant (validated by real experiments) with a support vector machine (SVM) to detect and classify possible faults. The adoption of a classification approach as an identification strategy in a model-based fault diagnosis process represents a major innovation in the field of SOFC plants. Constant–voltage and constant–current control strategies are investigated. In both cases, an adequately trained SVM classifier is used to provide a high probability of correct classification when the plant functions at different steady-state operating conditions for random sizes of the considered faults and for realistic magnitudes of the errors affecting the model predictions. In addition, the relative importance of the easy-to-measure residuals, which are used as features in the SVM classification process, are discussed based on an advanced feature selection technique.
Autors: Costamagna, P.;De Giorgi, A.;Magistri, L.;Moser, G.;Pellaco, L.;Trucco, A.;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Jun 2016, volume: 31, issue:2, pages: 676 - 687
Publisher: IEEE
 
» A Clearer Picture of Total Variation Blind Deconvolution
Abstract:
Blind deconvolution is the problem of recovering a sharp image and a blur kernel from a noisy blurry image. Recently, there has been a significant effort on understanding the basic mechanisms to solve blind deconvolution. While this effort resulted in the deployment of effective algorithms, the theoretical findings generated contrasting views on why these approaches worked. On the one hand, one could observe experimentally that alternating energy minimization algorithms converge to the desired solution. On the other hand, it has been shown that such alternating minimization algorithms should fail to converge and one should instead use a so-called Variational Bayes approach. To clarify this conundrum, recent work showed that a good image and blur prior is instead what makes a blind deconvolution algorithm work. Unfortunately, this analysis did not apply to algorithms based on total variation regularization. In this manuscript, we provide both analysis and experiments to get a clearer picture of blind deconvolution. Our analysis reveals the very reason why an algorithm based on total variation works. We also introduce an implementation of this algorithm and show that, in spite of its extreme simplicity, it is very robust and achieves a performance comparable to the top performing algorithms.
Autors: Perrone, D.;Favaro, P.;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Jun 2016, volume: 38, issue:6, pages: 1041 - 1055
Publisher: IEEE
 
» A CMOS Amperometric System for Multi-Neurotransmitter Detection
Abstract:
In vivo multi-target and selective concentration monitoring of neurotransmitters can help to unravel the brain chemical complex signaling interplay. This paper presents a dedicated integrated potentiostat transducer circuit and its selective electrode interface. A custom 2-electrode time-based potentiostat circuit was fabricated with 0.13 μm CMOS technology and provides a wide dynamic input current range of 20 pA to 600 nA with 56 μW, for a minimum sampling frequency of 1.25 kHz. A multi-working electrode chip is functionalized with carbon nanotubes (CNT)-based chemical coatings that offer high sensitivity and selectivity towards electroactive dopamine and non-electroactive glutamate. The prototype was experimentally tested with different concentrations levels of both neurotransmitter types, and results were similar to measurements with a commercially available potentiostat. This paper validates the functionality of the proposed biosensor, and demonstrates its potential for the selective detection of a large number of neurochemicals.
Autors: Massicotte, G.;Carrara, S.;Di Micheli, G.;Sawan, M.;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Jun 2016, volume: 10, issue:3, pages: 731 - 741
Publisher: IEEE
 
» A Coherency-Based Equivalence Method for MMC Inverters Using Virtual Synchronous Generator Control
Abstract:
This paper extends the previous virtual synchronous generator (VSG) control for voltage-source converters to modular multilevel converters (MMCs). Compared with the ac synchronous generator (SG), the VSG-based MMC is embedded with a power-angle characteristic. Starting from this feature and with reference to the existing ac system coherency-based equivalence methods, this paper proposes a novel coherency equivalence method for MMC used in large-scale renewable energy systems connected to the ac grid. This novel method mainly focuses on the coherency criterion and parameter aggregation methods which have significant differences compared with the ac system methods. The proposed equivalence method is validated on PSCAD/EMTDC and the study results indicate that: 1) the VSG-based MMC model does show the power-angle characteristic similar to the SG model; 2) the proposed coherency criterion can accurately and efficiently classify the paralleled MMC into coherent groups; and 3) the dynamic behaviors of the external systems are preserved after the aggregations of all previous coherency MMC groups.
Autors: Li, C.;Xu, J.;Zhao, C.;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Jun 2016, volume: 31, issue:3, pages: 1369 - 1378
Publisher: IEEE
 
» A Combined Deblocking Filter and SAO Hardware Architecture for HEVC
Abstract:
The latest video coding standard high-efficiency video coding (HEVC) provides 50% improvement in coding efficiency compared to H.264/AVC to meet the rising demands for video streaming, better video quality, and higher resolution. The deblocking filter (DF) and sample adaptive offset (SAO) play an important role in the HEVC encoder, and the SAO is newly adopted in HEVC. Due to the high throughput requirement in the video encoder, design challenges such as data dependence, external memory traffic, and on-chip memory area become even more critical. To solve these problems, we first propose an interlacing memory organization on the basis of quarter-LCU to resolve the data dependence between vertical and horizontal filtering of DF. The on-chip SRAM area is also reduced to about 25% on the basis of quarter-LCU scheme without throughput loss. We also propose a simplified bitrate estimation method of rate-distortion cost calculation to reduce the computational complexity in the mode decision of SAO. Our proposed hardware architecture of combined DF and SAO is designed for the HEVC intraencoder, and the proposed simplified bitrate estimation method of SAO can be applied to both intra- and intercoding. As a result, our design can support ultrahigh definition 7680 × 4320 at 40 f/s applications at merely 182 MHz working frequency. Total logic gate count is 103.3 K in 65 nm CMOS process.
Autors: Shen, W.;Fan, Y.;Bai, Y.;Huang, L.;Shang, Q.;Liu, C.;Zeng, X.;
Appeared in: IEEE Transactions on Multimedia
Publication date: Jun 2016, volume: 18, issue:6, pages: 1022 - 1033
Publisher: IEEE
 
» A Combined Model- and Learning-Based Framework for Interaction-Aware Maneuver Prediction
Abstract:
This paper presents a novel online-capable interaction-aware intention and maneuver prediction framework for dynamic environments. The main contribution is the combination of model-based interaction-aware intention estimation with maneuver-based motion prediction based on supervised learning. The advantages of this framework are twofold. On one hand, expert knowledge in the form of heuristics is integrated, which simplifies the modeling of the interaction. On the other hand, the difficulties associated with the scalability and data sparsity of the algorithm due to the so-called curse of dimensionality can be reduced, as a reduced feature space is sufficient for supervised learning. The proposed algorithm can be used for highly automated driving or as a prediction module for advanced driver assistance systems without the need of intervehicle communication. At the start of the algorithm, the motion intention of each driver in a traffic scene is predicted in an iterative manner using the game-theoretic idea of stochastic multiagent simulation. This approach provides an interpretation of what other drivers intend to do and how they interact with surrounding traffic. By incorporating this information into a Bayesian network classifier, the developed framework achieves a significant improvement in terms of reliable prediction time and precision compared with other state-of-the-art approaches. By means of experimental results in real traffic on highways, the validity of the proposed concept and its online capability is demonstrated. Furthermore, its performance is quantitatively evaluated using appropriate statistical measures.
Autors: Bahram, M.;Hubmann, C.;Lawitzky, A.;Aeberhard, M.;Wollherr, D.;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Jun 2016, volume: 17, issue:6, pages: 1538 - 1550
Publisher: IEEE
 
» A Compact Hydrostatic-Driven Electric Generator: Design, Prototype, and Experiment
Abstract:
This paper presents an integrated hydrostatic-driven electric generator, which can be employed to convert hydrostatic energy to electrical form directly. The machine with compact structure is realized by mounting a Halbach permanent magnet array which has self-shielding magnetic property on the barrel surface of an axial piston hydrostatic motor. A stator consisting of iron core and windings is installed concentrically on the outside of the permanent magnets. Then, according to electromagnetic theory, electrical power will be generated when the barrel and the magnets are driven to rotate by pressurized fluid. Parametric constraints required by the integration are analyzed and tradeoff designs of some significant parameters are implemented by using theoretical analysis and finite-element analysis. A prototype is fabricated based on the utilization of some standard parts, and tested under both of no-load and loaded conditions. The results demonstrate that the prototype has expected performances including small volume and moment of inertia, reasonable efficiency, as well as good output voltage stiffness and generation quality.
Autors: Wang, T.;Zhou, Z.;
Appeared in: IEEE/ASME Transactions on Mechatronics
Publication date: Jun 2016, volume: 21, issue:3, pages: 1612 - 1619
Publisher: IEEE
 
» A Compact Verilog-A Model of Silicon Carrier-Injection Ring Modulators for Optical Interconnect Transceiver Circuit Design
Abstract:
Optical interconnect system efficiency is dependent on the ability to optimize the transceiver circuitry for low-power and high-bandwidth operation, motivating co-simulation environments with compact optical device simulation models. This paper presents a compact Verilog-A silicon carrier-injection ring modulator model, which accurately captures both non-linear electrical and optical dynamics. The device's electrical behavior is described by a p-i-n diode SPICE model, while the optical response is captured with a dynamic ring resonator model, which considers the ring's cumulative phase shift. Experimental verification of the model is performed both at 8 Gb/s with symmetric drive signals to study the impact of pre-emphasis pulse duration, pulse depth, and dc bias, and at 9 Gb/s with a 65 nm CMOS driver capable of asymmetric pre-emphasis pulse duration. The potential for 15 Gb/s operation is shown by utilizing the presented model for optimization of the asymmetric pre-emphasis signal waveform.
Autors: Wang, B.;Li, C.;Chen, Chin-Hui;Yu, K.;Fiorentino, M.;Beausoleil, R.;Palermo, S.;
Appeared in: Journal of Lightwave Technology
Publication date: Jun 2016, volume: 34, issue:12, pages: 2996 - 3005
Publisher: IEEE
 
» A Comparative Study of the Effectiveness of CPU Consolidation Versus Dynamic Voltage and Frequency Scaling in a Virtualized Multicore Server
Abstract:
Companies operating large datacenters are focusing on how to reduce the electrical energy costs of operating datacenters. A common way of cost reduction is to perform a dynamic voltage and frequency scaling (DVFS), thereby matching the CPU’s performance and power level to incoming workloads. Another power saving technique is CPU consolidation, which uses the minimum number of CPUs necessary to meet the service request demands and turns OFF the remaining unused CPUs. DVFS has been already extensively studied and verified its effectiveness. On the other hand, it is necessary to study more about the effectiveness of CPU consolidation. Key questions that must be answered are how effectively the CPU consolidation improves the energy efficiency and how to maximize the improvement. These questions are addressed in this paper. After understanding modern power management techniques and developing an appropriate power model, this paper provides an extensive set of hardware-based experimental results and makes suggestions about how to maximize energy efficiency improvement through CPU consolidation. In addition, this paper also presents new online CPU consolidation algorithms, which reduce the energy-delay product up to 13% compared with the Linux default DVFS algorithm.
Autors: Hwang, i.;Pedram, M.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jun 2016, volume: 24, issue:6, pages: 2103 - 2116
Publisher: IEEE
 
» A Comparative Study of Unknown-Input Observers for Prognosis Applied to an Electromechanical System
Abstract:
In this paper, a contribution to solve the system prognostic problem is proposed. For that, the concept is defined in this work as a problem of predictive diagnosis under temporal constraint. Generally, this problem is treated using mainly approaches that are based on dynamic systems, experts' knowledge or are data-driven. Here, in order to describe the behavior of a process, we consider dynamic models that are composed of differential equations. The goal of this work is twofold. First, we present a new strategy for system prognosis based on observer design. Second, we propose a comparative study of two methodologies, dedicated to observer design, with application to an electromechanical process. To illustrate the performances of the approaches, simulation results are proposed.
Autors: Gucik-Derigny, D.;Outbib, R.;Ouladsine, M.;
Appeared in: IEEE Transactions on Reliability
Publication date: Jun 2016, volume: 65, issue:2, pages: 704 - 717
Publisher: IEEE
 
» A Constant Switching Frequency-Based Direct Torque Control Method for Interior Permanent-Magnet Synchronous Motor Drives
Abstract:
Direct torque control (DTC) is known to be a promising candidate for interior permanent-magnet synchronous motor drives. It provides fast dynamic response and good immunity to parameter variations. However, except for its merits, DTC also suffers from two major problems of variable switching frequency and large torque ripples. Research proposals have been published to solve these problems. Nonetheless, most of the proposals present very complex control algorithms. This paper proposes a constant switching frequency-based DTC algorithm for IPMSM drives. It consists of only one PI regulator and one triangular-wave carrier. The proposed algorithm reduces the torque ripples to a noticeable extent. In-depth analysis and design guidelines of the proposed controller are given. Simulation and experiment results are provided to verify the effectiveness of the proposed method.
Autors: Zhang, X.;Foo, G.;
Appeared in: IEEE/ASME Transactions on Mechatronics
Publication date: Jun 2016, volume: 21, issue:3, pages: 1445 - 1456
Publisher: IEEE
 
» A Contextualized System for Supporting Active Learning
Abstract:
The dynamics of the world today demands a change in traditional education paradigms to enable the creation of more efficient learning environments, where students will learn more effectively and will play a more active role in their education. They should interact with the knowledge at anytime-anywhere. In order to tackle this problem we should take advantage of mobile communication devices (e.g., smartphones and tablets) which are widely used by students and which have excellent processing storage and connectivity capabilities. In this research work, a context-aware system stimulating active learning by students was developed. This system places the student in an intelligent learning environment and is capable of delivering appropriate context-related learning contents, based on location, time, date, interaction of the student, profile of the student, and so on. Within its architecture, the system includes reasoning capability that using context-based ontology is able to deliver efficient learning resources. The experimental results obtained from various learning experiences in nursery, medicine, and systems engineering support the validity of our approach.
Autors: Gomez, J.E.;Huete, J.F.;Hernandez, V.L.;
Appeared in: IEEE Transactions on Learning Technologies
Publication date: Jun 2016, volume: 9, issue:2, pages: 196 - 202
Publisher: IEEE
 
» A Cumulative-Exposure-Based Algorithm for Failure Data From a Load-Sharing System
Abstract:
In a load-sharing system, total workloads are shared by all components and failure of one component increases stress of the surviving ones. The time interval between two consecutive component failures reflects component reliability under different stress and is of interest to us. This study develops an iterative algorithm for analysis of such data from load-sharing systems. In each iteration, we first obtain the equivalent operating time of each component under a given stress by capitalizing on the cumulative exposure principle. Then the equivalent operating times, which are simply right-censored, are fitted to update the parameter estimates. The conversion has closed forms for most common distributions such as the log-location-scale family and the gamma distribution, and the subsequent fitting of right-censored data is straightforward. Therefore, the algorithm is easy to implement compared with existing methods such as the maximum likelihood estimation. Convergence properties of the algorithm are investigated theoretically and through extensive simulations. Three examples representing different types of real problems are used to demonstrate the proposed algorithm.
Autors: Kong, Y.N.;Ye, Z.-S.;
Appeared in: IEEE Transactions on Reliability
Publication date: Jun 2016, volume: 65, issue:2, pages: 1001 - 1013
Publisher: IEEE
 
» A Cyber-Physical System for Environmental Monitoring
Abstract:
This paper presents the development of a cyber-physical system that monitors the environmental conditions or the ambient conditions in indoor spaces at remote locations. The communication between the system's components is performed using the existent wireless infrastructure based on the IEEE 802.11 b/g standards. The resulted solution provides the possibility of logging measurements from locations all over the world and of visualizing and analyzing the gathered data from any device connected to the Internet. This work encompasses the complete solution, a cyber-physical system, starting from the physical level, consisting of sensors and the communication protocol, and reaching data management and storage at the cyber level. The experimental results show that the proposed system represents a viable and straightforward solution for environmental and ambient monitoring applications.
Autors: Mois, G.;Sanislav, T.;Folea, S.C.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jun 2016, volume: 65, issue:6, pages: 1463 - 1471
Publisher: IEEE
 
» A Data Passivity-Enforcement Preprocessing Approach to Multiport System Modeling
Abstract:
The passivity enforcement problem is always a key issue when estimating passive black-box models. Passivity has been broadly scrutinized in the literature and is known to yield stable time-domain simulation; thus, passivity is a much-desired model property which cannot remain an unmodeled effect. Many successful algorithms exist that accomplish the enforcement task by model parameter perturbation, with the caveat that the passivity violations to be suppressed are not large. This paper proposes a novel approach to address this issue. We propose four different mathematical formulations to preprocess the measurement of admittance parameters. Preprocessed data serve as inputs to parameter estimation algorithms to obtain passive models for power system applications. This approach is particularly adequate to use with model parameter perturbation methods. Three examples containing data of actual measurements illustrate the advantage of using the proposed methodology.
Autors: Ihlenfeld, L.P.R.K.;Oliveira, G.H.C.;Sans, M.R.;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Jun 2016, volume: 31, issue:3, pages: 1351 - 1359
Publisher: IEEE
 
» A Decentralized Control Method for Islanded Microgrids Under Unbalanced Conditions
Abstract:
Unbalanced load currents not only give rise to unbalanced voltages but also adversely affect the performance of the conventional current-limiting mechanisms. The latter might result in overcurrent stress on the distributed energy resources (DERs) or current harmonics. In this paper, a novel decentralized control method is proposed to improve the power quality and protect DERs from overload. The proposed controller makes use of the model predictive control (MPC) technique to minimize the voltage unbalance, improve current limiting, and prevent active power overload. The MPC is combined with the - droop method to realize coordinated operation with fast dynamic response. The proposed method is tested on the CIGRE benchmark microgrid. Simulation results demonstrate that the proposed method improves power quality but also allows for operation close to the maximum load capacity without imposing DERs to overload.
Autors: Golsorkhi Esfahani, M.S.;Lu, D.D.C.;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Jun 2016, volume: 31, issue:3, pages: 1112 - 1121
Publisher: IEEE
 
» A Deep and Autoregressive Approach for Topic Modeling of Multimodal Data
Abstract:
Topic modeling based on latent Dirichlet allocation (LDA) has been a framework of choice to deal with multimodal data, such as in image annotation tasks. Another popular approach to model the multimodal data is through deep neural networks, such as the deep Boltzmann machine (DBM). Recently, a new type of topic model called the Document Neural Autoregressive Distribution Estimator (DocNADE) was proposed and demonstrated state-of-the-art performance for text document modeling. In this work, we show how to successfully apply and extend this model to multimodal data, such as simultaneous image classification and annotation. First, we propose SupDocNADE, a supervised extension of DocNADE, that increases the discriminative power of the learned hidden topic features and show how to employ it to learn a joint representation from image visual words, annotation words and class label information. We test our model on the LabelMe and UIUC-Sports data sets and show that it compares favorably to other topic models. Second, we propose a deep extension of our model and provide an efficient way of training the deep model. Experimental results show that our deep model outperforms its shallow version and reaches state-of-the-art performance on the Multimedia Information Retrieval (MIR) Flickr data set.
Autors: Zheng, Y.;Zhang, Yu-Jin;Larochelle, H.;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Jun 2016, volume: 38, issue:6, pages: 1056 - 1069
Publisher: IEEE
 
» A Discounted Trade Reduction Mechanism for Dynamic Ridesharing Pricing
Abstract:
Dynamic ridesharing arranges shared rides for passengers and drivers in real time. Since, in many dynamic ridesharing services, drivers are crowdsourced, the price mechanism design for such services is a fundamental problem. In this paper, a discounted trade reduction mechanism is designed for dynamic ridesharing pricing. Properties of the proposed mechanism are investigated. We also conduct experiments to evaluate the price mechanism. Experimental results show that our mechanism outperforms three double auction baseline mechanisms and illustrate the effect of adjusting the parameter values of our mechanism.
Autors: Zhang, J.;Wen, D.;Zeng, S.;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Jun 2016, volume: 17, issue:6, pages: 1586 - 1595
Publisher: IEEE
 
» A Distributed and Scalable Approach to Semi-Intrusive Load Monitoring
Abstract:
Non-intrusive appliance load monitoring (NIALM) helps identify major energy guzzlers in a building without introducing extra metering cost. It motivates users to take proper actions for energy saving and greatly facilitates demand response (DR) programs. Nevertheless, NIALM of large-scale appliances is still an open challenge. To pursue a scalable solution to energy monitoring for contemporary large-scale appliance groups, we propose a distributed metering platform and use parallel optimization for semi-intrusive appliance load monitoring (SIALM). Based on a simple power model, a sparse switching event recovering (SSER) model is established to recover appliance states from their aggregated load data. Furthermore, the sufficient conditions for unambiguous state recovery of multiple appliances are presented. By considering these conditions as well as the electrical network topology constraint, a minimum number of meters are obtained to correctly recover the energy consumption of individual appliances. We evaluate the performance of both SIALM and NIALM with real-world trace data and synthetic data. The results demonstrate that with the help of a small number of meters, the SIALM approach significantly improves the accuracy of energy disaggregation for large-scale appliances.
Autors: Tang, G.;Wu, K.;Lei, J.;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jun 2016, volume: 27, issue:6, pages: 1553 - 1565
Publisher: IEEE
 
» A Fast and Retargetable Framework for Logic-IP-Internal Electromigration Assessment Comprehending Advanced Waveform Effects
Abstract:
A new methodology for system-on-chip-level logic-IP-internal electromigration verification is presented in this paper, which significantly improves accuracy by comprehending the impact of the parasitic loading and voltage-dependent pin capacitance in the library model. It additionally provides an on-the-fly retargeting capability for reliability constraints by allowing arbitrary specifications of lifetimes, temperatures, voltages, and failure rates, as well as interoperability of the IPs across foundries. The characterization part of the methodology is expedited through the intelligent IP-response modeling. The ultimate benefit of the proposed approach is demonstrated on a 28-nm design by providing an on-the-fly specification of retargeted reliability constraints. The results show a high correlation with SPICE and were obtained with an order of magnitude reduction in the verification runtime.
Autors: Jain, P.;Cortadella, J.;Sapatnekar, S.S.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jun 2016, volume: 24, issue:6, pages: 2345 - 2358
Publisher: IEEE
 
» A Fault-Tolerant Direct Torque Control for Six-Phase Permanent Magnet Synchronous Motor With Arbitrary Two Opened Phases Based on Modified Variables
Abstract:
A fault-tolerant direct torque control (DTC) strategy for six-phase symmetrical winding shifted-phase 60° permanent magnet synchronous motor with arbitrary two opened phases is proposed in this paper. First, the relationship between flux and electromagnetic torque based on the modified stator flux and modified rotor flux is researched. Second, the optimal control strategy based on the relationship between modified stator voltage vector and modified stator flux on αβ plane, and the relationship between zero-sequence voltage and zero-sequence current is constructed. According to the control strategy, the modified stator flux, electromagnetic torque, and zero-sequence current are controlled by different switching combinations of four-phase inverter bridge. The results of analysis and experiments show that the presented DTC drive system has fast and smooth torque response, and the four-phase stator currents with same peak value are sinusoidal due to the controlled zero sequence current.
Autors: Zhou, Y.;Lin, X.;Cheng, M.;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Jun 2016, volume: 31, issue:2, pages: 549 - 556
Publisher: IEEE
 
» A Flexible Infrastructure for Dynamic Power Control of Electric Vehicle Battery Chargers
Abstract:
This paper proposes a flexible infrastructure for dynamic power control (FIDPC) of electric vehicle (EV) battery chargers. This infrastructure dynamically adjusts the EV battery charger current, according to the power demand of the home wherein the vehicle is plugged. An infrastructure was implemented to validate this proposal. This infrastructure is composed by an EV battery charger and a communication system based on a radio-frequency (RF) interface. The battery charger has nominal power of 3.6 kVA and operates with sinusoidal current and unitary total power factor, whereas the RF interface provides continuous data flow to the battery charger with information on the home total current consumption (root-mean-square value). Experimental tests were performed under realistic conditions to validate the concept behind the proposed FIDPC. These tests served to assess the behavior of the EV battery charger with dynamic power control on a single-phase 230-V 16-A 50-Hz residential electrical installation. The experimental results confirm the quick time response of the FIDPC, even when working under heavy-home-load variations.
Autors: Monteiro, V.;Carmo, J.;Pinto, G.;Afonso, J.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jun 2016, volume: 65, issue:6, pages: 4535 - 4547
Publisher: IEEE
 
» A Game-Theoretic Approach to Optimal Scheduling of Parking-Lot Electric Vehicle Charging
Abstract:
Parking-lot electric vehicle (EV) charging promises reduced on-board battery capacity for commuters, which would decrease the payback time. However, the parking-lot EV charging scenario is rendered complicated by the large number of agents involved and highly dynamic price of electricity during the day. This study solves the parking-lot EV charging scheduling problem through a noncooperative game approach that considers the coupled constraint therein. The total charging amount is restrained by the transformer capacity. Such a coupled constraint makes the parking-lot EV charging game distinct from other EV charging scenarios. The theoretical framework of the Rosen–Nash normalized equilibrium is applied to deal with such a problem. The Nikaido–Isoda relaxation algorithm is used to calculate the equilibrium point. The dynamic game extension is then provided. Numerical simulation validates the proposed framework. Moreover, the impact of major parameters of the EV charging game on the equilibrium point that can be achieved is investigated.
Autors: Lei, Z.;Li, Y.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jun 2016, volume: 65, issue:6, pages: 4068 - 4078
Publisher: IEEE
 
» A Game-Theoretic Approach to Replanning-Aware Interactive Scene Prediction and Planning
Abstract:
This paper presents a novel cooperative-driving prediction and planning framework for dynamic environments based on the methods of game theory. The proposed algorithm can be used for highly automated driving on highways or as a sophisticated prediction module for advanced driver-assistance systems with no need for intervehicle communication. The main contribution of this paper is a model-based interaction-aware motion prediction of all vehicles in a scene. In contrast to other state-of-the-art approaches, the system also models the replanning capabilities of all drivers. With that, the driving strategy is able to capture complex interactions between vehicles, thus planning maneuver sequences over longer time horizons. It also enables an accurate prediction of traffic for the next immediate time step. The prediction model is supported by an interpretation of what other drivers intend to do, how they interact with traffic, and the ongoing observation. As part of the prediction loop, the proposed planning strategy incorporates the expected reactions of all traffic participants, offering cooperative and robust driving decisions. By means of experimental results under simulated highway scenarios, the validity of the proposed concept and its real-time capability is demonstrated.
Autors: Bahram, M.;Lawitzky, A.;Friedrichs, J.;Aeberhard, M.;Wollherr, D.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jun 2016, volume: 65, issue:6, pages: 3981 - 3992
Publisher: IEEE
 
» A General Privacy-Preserving Auction Mechanism for Secondary Spectrum Markets
Abstract:
Auctions are among the best-known market-based tools to solve the problem of dynamic spectrum redistribution. In recent years, a good number of strategy-proof auction mechanisms have been proposed to improve spectrum utilization and to prevent market manipulation. However, the issue of privacy preservation in spectrum auctions remains open. On the one hand, truthful bidding reveals bidders’ private valuations of the spectrum. On the other hand, coverage/interference areas of the bidders may be revealed to determine conflicts. In this paper, we present PISA, which is a PrIvacy preserving and Strategy-proof Auction mechanism for spectrum allocation. PISA provides protection for both bid privacy and coverage/interference area privacy leveraging a privacy-preserving integer comparison protocol, which is well applicable in other contexts. We not only theoretically prove the privacy-preserving properties of PISA, but also extensively evaluate its performance. Evaluation results show that PISA achieves good spectrum allocation efficiency with light computation and communication overheads.
Autors: Huang, Q.;Gui, Y.;Wu, F.;Chen, G.;Zhang, Q.;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Jun 2016, volume: 24, issue:3, pages: 1881 - 1893
Publisher: IEEE
 
» A Generalized Age Replacement Policy for Systems Under Renewing Repair-Replacement Warranty
Abstract:
This paper presents a warranty cost model for repairable products when an age replacement policy is adopted in conjunction with the renewal of a minimal repair-replacement warranty. A study of the optimal choice of the preventive replacement age is also presented. When renewing a minimal repair-replacement warranty, either minimal repair is carried out or the product is replaced, depending on the length of repair time when the product failures occur during the warranty period. In this study, we develop mathematical formulas to evaluate the long-run expected cost rates during the life cycle of the product under the proposed cost models and determine the optimal preventive replacement ages by minimizing the objective functions. Furthermore, the effects of the renewing warranty on the optimal preventive replacement age and its corresponding expected cost rate are investigated for various situations regarding the warranty policy. This study extends the existing results on the age replacement policy by considering situations that are more practical, where both minimal repair and replacement are considered simultaneously upon product failure. Assuming that the product deteriorates with age, we illustrate our proposed cost model and its optimization using numerical examples and observe the impact of relevant parameters on the optimal solutions regarding the preventive replacement age.
Autors: Park, M.;Jung, K.M.;Park, D.H.;
Appeared in: IEEE Transactions on Reliability
Publication date: Jun 2016, volume: 65, issue:2, pages: 604 - 612
Publisher: IEEE
 
» A Generalized Griffith Importance Measure for Components With Multiple State Transitions
Abstract:
The performance of the system is often influenced by the performance of a particular component. Hence, it is important to identify the state changing of which component dominates the system performance changing in a maintenance process. Motivated by the Griffith importance measure (GIM) model, this paper proposed the generalized GIM, which extends the application of GIM to complex multi-state components, to evaluate the accurate contribution of the components in the changing of the system performance by considering the transition probabilities of the states of each component. Furthermore, the generalized GIM method is successfully applied in the continuous-state systems by extending the system structure function in GIM model. As a result, the expression of the performance of continuous system and the generalized GIM of the continuous-state components are proposed. A numerical example and an application to an oil transportation system are presented to illustrate how the proposed method works.
Autors: Liu, Y.;Si, S.;Cui, L.;Wang, Z.;Sun, S.;
Appeared in: IEEE Transactions on Reliability
Publication date: Jun 2016, volume: 65, issue:2, pages: 662 - 673
Publisher: IEEE
 
» A Harmonic Suppression Method Based on Fractional Lower Order Statistics for Power System
Abstract:
Impulse noise in power systems would seriously degrade the harmonic suppression performance. To remedy this problem, a novel harmonic suppression method based on fractional lower order statistics (FLOS) is proposed in this paper. In the proposed method, impulse noise is modeled by alpha-stable distribution. Then, the ESPRIT spectrum estimation algorithm is improved by FLOS for impulse noise and used to estimate the fundamental frequency of power signal, and the frequency of each harmonic component is obtained from this estimated frequency. Next, the amplitude of each harmonic component is estimated by a modified recursive least squares (RLS) algorithm. Finally, a harmonic compensation signal is generated by the active power filter based on the estimated frequencies and amplitudes to cancel original harmonics. The proposed method has a competitive advantage that it can suppress harmonics well even if the impulse noise activating and has a fast tracking ability for changing harmonics. Also, due to the use of self-sensing actuator principle, the proposed method can not only guarantee the performance of suppressing harmonics at normal operation states, but also ensure not to amplify harmonics in case of malfunction. The simulation results show that the proposed method has a better harmonic suppression performance than the existing ones under the impulse noise environment. The real experiments are also presented to verify the feasibility of the proposed method.
Autors: Chen, Z.;Geng, X.;Yin, F.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jun 2016, volume: 63, issue:6, pages: 3745 - 3755
Publisher: IEEE
 
» A High Throughput List Decoder Architecture for Polar Codes
Abstract:
While long polar codes can achieve the capacity of arbitrary binary-input discrete memoryless channels when decoded by a low complexity successive-cancellation (SC) algorithm, the error performance of the SC algorithm is inferior for polar codes with finite block lengths. The cyclic redundancy check (CRC)-aided SC list (SCL) decoding algorithm has better error performance than the SC algorithm. However, current CRC-aided SCL decoders still suffer from long decoding latency and limited throughput. In this paper, a reduced latency list decoding (RLLD) algorithm for polar codes is proposed. Our RLLD algorithm performs the list decoding on a binary tree, whose leaves correspond to the bits of a polar code. In existing SCL decoding algorithms, all the nodes in the tree are traversed, and all possibilities of the information bits are considered. Instead, our RLLD algorithm visits much fewer nodes in the tree and considers fewer possibilities of the information bits. When configured properly, our RLLD algorithm significantly reduces the decoding latency and, hence, improves throughput, while introducing little performance degradation. Based on our RLLD algorithm, we also propose a high throughput list decoder architecture, which is suitable for larger block lengths due to its scalable partial sum computation unit. Our decoder architecture has been implemented for different block lengths and list sizes using the TSMC 90-nm CMOS technology. The implementation results demonstrate that our decoders achieve significant latency reduction and area efficiency improvement compared with the other list polar decoders in the literature.
Autors: Lin, J.;Xiong, C.;Yan, Z.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jun 2016, volume: 24, issue:6, pages: 2378 - 2391
Publisher: IEEE
 
» A High-Throughput Cantilever Array Sensor for Multiple Liver Cancer Biomarkers Detection
Abstract:
A novel microcantilever biosensor was batch-fabricated with integrated circuit compatible micro-electro-mechanical system technology for joint detection of liver cancer biomarkers with high sensitivity, high throughput, high specification, and good precision. A micro-cavity was designed in the free end of the cantilever for local antibody-immobilization using micro-printing system, which can dramatically reduce the effect of adsorption-induced stiffness coefficient variation. A linear relationship between the resonance frequency shift and the antigen concentration was observed for three liver cancer biomarkers, alpha-fetoprotein, -glutamyl transpeptidase II, and hepatocyte growth factor. In addition, the presented immunosensing method has little cross reactivity to different antigens, paving the way to a highly specific technique. These approaches will promote clinical application of the cantilever sensors in early cancer diagnosis.
Autors: Wang, J.;Zhu, Y.;Wang, X.;Wang, S.;Yang, J.;Yang, F.;
Appeared in: IEEE Sensors Journal
Publication date: Jun 2016, volume: 16, issue:12, pages: 4675 - 4682
Publisher: IEEE
 
» A Humanoid Robotic Wrist With Two-Dimensional Series Elastic Actuation for Accurate Force/Torque Interaction
Abstract:
It has been a challenge to design humanoid robots that possess intrinsic compliant actuation, especially for robots that are required to be manipulated multidimensionally. Adapting from human limbs, robotic manipulators with internal mechanical compliance can perform high-quality force/torque control and more safely interact with humans. This paper presents a humanoid robotic wrist whose size, range-of-motion, and torque density are comparable to those of a human wrist. To achieve 2-D series elastic actuation, two internal compliant couplers are proposed. Through slider crank and spherical mechanisms, the linear elasticity is converted to rotary elasticity to control the pitch and yaw torques at the same time. This new compact design realizes series elastic actuation in two perpendicular axes without increasing size or complexity relative to that without series elastic actuation. Experiments using a prototype demonstrate that the wrist can achieve accurate and fast force/torque control. We expect this novel compliant wrist to serve as an alternative for applications involving human-robot interaction.
Autors: Li, Yu-Feng;Chu, Cheng-Yu;Xu, Jia-You;Lan, Chao-Chieh;
Appeared in: IEEE/ASME Transactions on Mechatronics
Publication date: Jun 2016, volume: 21, issue:3, pages: 1315 - 1325
Publisher: IEEE
 
» A Hybrid-STATCOM With Wide Compensation Range and Low DC-Link Voltage
Abstract:
This paper proposes a hybrid static synchronous compensator (hybrid-STATCOM) in a three-phase power transmission system that has a wide compensation range and low dc-link voltage. Because of these prominent characteristics, the system costs can be greatly reduced. In this paper, the circuit configuration of hybrid-STATCOM is introduced first. Its V-I characteristic is then analyzed, discussed, and compared with traditional STATCOM and capacitive-coupled STATCOM (C-STATCOM). The system parameter design is then proposed on the basis of consideration of the reactive power compensation range and avoidance of the potential resonance problem. After that, a control strategy for hybrid-STATCOM is proposed to allow operation under different voltage and current conditions, such as unbalanced current, voltage dip, and voltage fault. Finally, simulation and experimental results are provided to verify the wide compensation range and low dc-link voltage characteristics and the good dynamic performance of the proposed hybrid-STATCOM.
Autors: Wang, L.;Lam, Chi-Seng;Wong, Man-Chung;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jun 2016, volume: 63, issue:6, pages: 3333 - 3343
Publisher: IEEE
 
» A Linear Program for System-Level Control of Regional PHEV Charging Stations
Abstract:
This paper studies dynamic control of a system of plug-in hybrid electric vehicle (PHEV) charging stations. A finite horizon stochastic program is presented. Based upon the 15-min updated period of the electricity market price, the objective function is to maximize profit, which is the revenue benefit from selling back to the grid and the charging of the vehicles minus the cost of buying electricity from the grid. The state variables in each 15-min time period consist of the total wind purchased from the system, solar power generation at each charging station, total demand at each station, and nodal market price at stations’ location. A stochastic program is formulated, and the mean value problem as a deterministic linear program is solved. Potential strategies are presented to provide insight into the behavior of the system.
Autors: Kulvanitchaiyanunt, A.;Sarikprueck, P.;Lee, W.-J.;Rosenberger, J.;Chen, V.C.P.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jun 2016, volume: 52, issue:3, pages: 2046 - 2052
Publisher: IEEE
 
» A Location-Wise Predetermined Deployment for Optimizing Lifetime in Visual Sensor Networks
Abstract:
Visual sensor networks are receiving significant attention due to their potential applications ranging from surveillance to tracking domains. Nevertheless, due to the funneling effect, the unbalanced energy usage among visual sensor nodes (SNs) increases and leads to premature decrease in network lifetime. First, considering Rayleigh fading channel and routing models, we analyze the optimization of network lifetime by balancing the energy consumption among different SNs. From the analysis, it is revealed that the number of SNs and relay nodes and their locations have significant influence on limiting the energy hole problem and optimization of network lifetime. Based on the derived principle of energy balancing, we develop a heterogeneous SNs deployment strategy leading to optimization in network lifetime. Exhaustive simulation is performed, primarily to measure the extent of achieving our design goal of optimizing network lifetime while attaining energy balancing. We also measure the effect of placement errors on the performance and robustness of the scheme. The results show that even in the presence of placement error the performance is comparable and provides better robustness compared with the competing scheme. Further, the simulation results show that our scheme does not compromise with other performance metrics, e.g., end-to-end delay and throughput, while achieving the design goal. Finally, all the comparative results confirm our scheme’s supremacy over the competing schemes.
Autors: Halder, S.;Ghosal, A.;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Jun 2016, volume: 26, issue:6, pages: 1131 - 1145
Publisher: IEEE
 
» A Loosely-Coupled Full-System Multicore Simulation Framework
Abstract:
Full-system simulation is critical in evaluating design alternatives for multicore processors. However, state-of-the-art multicore simulators either lack good extensibility due to their tightly-coupled design between functional model (FM) and timing model (TM), or cannot guarantee cycle-accuracy. This paper conducts a comprehensive study on factors affecting cycle-accuracy and uncovers several contributing factors less studied before. Based on these insights, we propose a loosely-coupled functional-driven full-system simulator for multicore, namely Transformer. To ensure extensibility and cycle-accuracy, Transformer leverages an architecture-independent interface between FM and TM and uses a lightweight scheme to detect and recover from execution divergence between FM and TM. Built upon Transformer and its foundational simulator components, a graduate student only needed to write about 180 lines of code to extend an X86 functional model (QEMU) in Transformer. Moreover, the loosely-coupled design also removes the complex interaction between FM and TM and opens the opportunity to parallelize FM and TM to improve performance. Experimental results show that Transformer achieves an average of 8.4 and 7.0 percent performance improvement over GEMS in 4-core and 8-core configuration while guaranteeing cycle-accuracy. A further parallelization between FM and TM leads to 35.3 and 29.7 percent performance improvement respectively.
Autors: Zhang, W.;Wang, H.;Lu, Y.;Chen, H.;Zhao, W.;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jun 2016, volume: 27, issue:6, pages: 1566 - 1578
Publisher: IEEE
 
» A Low-Complexity Bit-Loading Algorithm for OFDM Systems Under Spectral Mask Constraint
Abstract:
This letter aims to solve the power minimization problem for interference-free OFDM systems under achievable throughput and spectral mask constraints. To this end, we use a general analytic formula to yield an efficient initial bit vector, i.e., given a total number of bits, the total power use corresponding to an efficient bit vector is minimum. We propose a low-complexity algorithm that achieves the global optimum of the problem. We theoretically prove that the number of bits required to add/remove, starting from the efficient initial bit vector, is upper bounded by the sum of half the number of active subcarriers and an arbitrary tolerance value. Simulation results show that the total power consumption is minimized with significant reduction of the computation cost as compared to other optimum algorithms.
Autors: Vo, N.;Amis, K.;Chonavel, T.;Siohan, P.;
Appeared in: IEEE Communications Letters
Publication date: Jun 2016, volume: 20, issue:6, pages: 1076 - 1079
Publisher: IEEE
 
» A Low-Cost Low-Power Ring Oscillator-Based Truly Random Number Generator for Encryption on Smart Cards
Abstract:
The design of a low-cost low-power ring oscillator-based truly random number generator (TRNG) macrocell, which is suitable to be integrated in smart cards, is presented. The oscillator sampling technique is exploited, and a tetrahedral oscillator with large jitter has been employed to realize the TRNG. Techniques to improve the statistical quality of the ring oscillator-based TRNGs' bit sequences have been presented and verified by simulation and measurement. A postdigital processor is added to further enhance the randomness of the output bits. Fabricated in the HHNEC 0.13- standard CMOS process, the proposed TRNG has an area as low as 0.005 mm2. Powered by a single 1.8-V supply voltage, the TRNG has a power consumption of 40 . The bit rate of the TRNG after postprocessing is 100 kb/s. The proposed TRNG has been made into an IP and successfully applied in an SD card for encryption application. The proposed TRNG has passed the National Institute of Standards and Technology tests and Diehard tests.
Autors: Dongsheng, L.;Zilong, L.;Lun, L.;Xuecheng, Z.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jun 2016, volume: 63, issue:6, pages: 608 - 612
Publisher: IEEE
 
» A Low-Power ASIC Signal Processor for a Vestibular Prosthesis
Abstract:
A low-power ASIC signal processor for a vestibular prosthesis (VP) is reported. Fabricated with TI 0.35 μm CMOS technology and designed to interface with implanted inertial sensors, the digitally assisted analog signal processor operates extensively in the CMOS subthreshold region. During its operation the ASIC encodes head motion signals captured by the inertial sensors as electrical pulses ultimately targeted for in-vivo stimulation of vestibular nerve fibers. To achieve this, the ASIC implements a coordinate system transformation to correct for misalignment between natural sensors and implanted inertial sensors. It also mimics the frequency response characteristics and frequency encoding mappings of angular and linear head motions observed at the peripheral sense organs, semicircular canals and otolith. Overall the design occupies an area of 6.22 mm 2 and consumes 1.24 mW when supplied with ± 1.6 V.
Autors: Toreyin, H.;Bhatti, P.T.;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Jun 2016, volume: 10, issue:3, pages: 768 - 778
Publisher: IEEE
 
» A Low-Power Broad-Bandwidth Noise Cancellation VLSI Circuit Design for In-Ear Headphones
Abstract:
Conventional active noise cancelling (ANC) headphones often perform well in reducing the low-frequency noise and isolating the high-frequency noise by earmuffs passively. The existing ANC systems often use high-speed digital signal processors to cancel out disturbing noise, which results in high power consumption for a commercial ANC headphone. The contribution of this paper can be classified into: 1) proper filter length selection; 2) low-power storage mechanism for convolution operation; and 3) high-throughput pipelining architecture. With these novel techniques, we develop an area-/power-efficient ANC circuit by using the TSMC 90-nm CMOS technology for in-ear headphone applications. The proposed feedforward filtered-x least mean square ANC circuit design provides the features of using lower operating frequency and consuming much less power that facilitate better performance than the conventional ANC headphones. To verify the effectiveness of the proposed design, a series of physical measurements is executed in an anechoic chamber. Measurement results show that the proposed high-performance/low-power circuit design can reduce disturbing noise of various frequency bands very well, and outperforms the existing works. The proposed design can attenuate 15 dB for broadband pink noise between 50 and 1500 Hz when operated at 20-MHz clock frequency at the costs of 84.2 k gates and power consumption of 6.59 mW only. Compared with the existing designs, the proposed work achieves higher noise cancellation performance in terms of 3 dB further and saves 97% power consumption.
Autors: Vu, H.-S.;Chen, K.-H.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jun 2016, volume: 24, issue:6, pages: 2013 - 2025
Publisher: IEEE
 
» A Low-Power Two-Tap Voltage-Mode Transmitter With Precisely Matched Output Impedance Using an Embedded Calibration Circuit
Abstract:
In this brief, a low-power two-tap voltage-mode transmitter (TX) with precisely matched output impedance using an embedded calibration circuit for dc-coupled unidirectional links is proposed. The proposed TX adopts an N-over-N driver with a supply voltage of 0.4 V in order to reduce the power consumption of the output driver. Its output driver is configured as a two-tap Finite Impulse Response (FIR) filter in order to compensate for channel loss at high frequency. In addition, the proposed embedded impedance calibration circuit precisely matches the impedance of the output driver to the channel characteristic impedance by using the receiver termination resistor instead of external reference resistors. The proposed two-tap voltage-mode TX is fabricated using a 90-nm low-power CMOS process technology and occupies an active area of 0.054 mm2. The measurement results show that the matching error of the output impedance is between −0.6% and +0.8%, and the power efficiency is 0.75 pJ/b without equalization and 0.94 pJ/b with 6-dB equalization, at a data rate of 5.0 Gb/s.
Autors: Kwak, Kang-Sub;Ra, Jong-Hyun;Moon, Ho-Seong;Hong, Seong-Kwan;Kwon, Oh-Kyong;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jun 2016, volume: 63, issue:6, pages: 573 - 577
Publisher: IEEE
 
» A Low-Voltage PLL With a Supply-Noise Compensated Feedforward Ring VCO
Abstract:
A low-voltage phase-locked-loop (PLL) circuit with a supply-noise-compensated feedforward ring voltage-controlled oscillator (FRVCO) is demonstrated. The oscillation frequency fluctuation due to supply noise is compensated by adjusting the ratio of driving strength in feedforward and direct paths in FRVCO. A prototype 400-MHz PLL circuit operating at 0.65 V is fabricated with 180-nm standard CMOS process. Measurement results show that supply-noise compensation is successfully achieved. Our PLL consumes only 242.1 .
Autors: Kim, Sung-Geun;Rhim, J.;Kwon, Dae-Hyun;Kim, Min-Hyeong;Choi, Woo-Young;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jun 2016, volume: 63, issue:6, pages: 548 - 552
Publisher: IEEE
 
» A Memristive Pascaline
Abstract:
The original Pascaline was a mechanical calculator able to sum and subtract integers. It encodes information in the angles of the mechanical components (such as wheels and cylinders), is aided by gravity, and performs the calculations. Here, we show that such a concept can be realized in electronics using memory elements such as memristive systems. By using memristive emulators, we have demonstrated experimentally the memcomputing version of the mechanical Pascaline, capable of processing and storing the numerical results in the multiple levels of each memristive element. Our result is the first experimental demonstration of multidigit arithmetic with multilevel memory devices that further emphasize the versatility and potential of memristive systems for future on-chip information processing and storage architectures.
Autors: Pershin, Y.;Castelano, L.;Hartmann, F.;Lopez-Richard, V.;Di Ventra, M.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jun 2016, volume: 63, issue:6, pages: 558 - 562
Publisher: IEEE
 
» A Methodology for Cognitive NoC Design
Abstract:
The number of cores in a multicore chip design has been increasing in the past two decades. The rate of increase will continue for the foreseeable future. With a large number of cores, the on-chip communication has become a very important design consideration. The increasing number of cores will push the communication complexity level to a point where managing such highly complex systems requires much more than what designers can anticipate for. We propose a new design methodology for implementing a cognitive network-on-chip that has the ability to recognize changes in the environment and to learn new ways to adapt to the changes. This learning capability provides a way for the network to manage itself. Individual network nodes work autonomously to achieve global system goals, e.g., low network latency, higher reliability, power efficiency, adaptability, etc. We use fault-tolerant routing as a case study. Simulation results show that the cognitive design has the potential to outperform the conventional design for large applications. With the great inherent flexibility to adopt different algorithms, the cognitive design can be applied to many applications.
Autors: Wu, W.;Louri, A.;
Appeared in: Computer Architecture Letters
Publication date: Jun 2016, volume: 15, issue:1, pages: 1 - 4
Publisher: IEEE
 
» A Mismatch-Insensitive Skew Compensation Architecture for Clock Synchronization in 3-D ICs
Abstract:
Traditional die-to-die (DTD) clock skew compensation topologies prerequisite matched delay lines or equal through-silicon via (TSV) delays. Unlike previous techniques, the proposed mismatch-insensitive skew compensation architecture can maintain a synchronous clock signal between two dies, while completely eliminating any skew arising from code-dependent mismatch in delay lines or unequal TSV delays. The performance of our design is verified in theory and simulation in light of mismatch/finite resolution of delay lines, clock jitter, phase detector dead zone, TSV delay, and buffer mismatch. Postsynthesis timing verification of this cell-based design was done in a 65-nm CMOS process. Under similar worse case mismatch conditions, the residual skew in the proposed architecture was delimited to 32 ps at 1 GHz, compared with 116 ps for a recent DTD topology, while consuming only 2.1 mW.
Autors: Sandhu, T.S.;El-Sankary, K.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jun 2016, volume: 24, issue:6, pages: 2026 - 2039
Publisher: IEEE
 
» A Modeling Framework for Generation of Positional and Temporal Simulations of Transcriptional Regulation
Abstract:
We present a modeling framework aimed at capturing both the positional and temporal behavior of transcriptional regulatory proteins in eukaryotic cells. There is growing evidence that transcriptional regulation is the complex behavior that emerges not solely from the individual components, but rather from their collective behavior, including competition and cooperation. Our framework describes individual regulatory components using generic action oriented descriptions of their biochemical interactions with a DNA sequence. All the possible actions are based on the current state of factors bound to the DNA. We developed a rule builder to automatically generate the complete set of biochemical interaction rules for any given DNA sequence. Off-the-shelf stochastic simulation engines can model the behavior of a system of rules and the resulting changes in the configuration of bound factors can be visualized. We compared our model to experimental data at well-studied loci in yeast, confirming that our model captures both the positional and temporal behavior of transcriptional regulation.
Autors: Knox, D.A.;Dowell, R.D.;
Appeared in: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Publication date: Jun 2016, volume: 13, issue:3, pages: 459 - 471
Publisher: IEEE
 
» A Modified Relevance Vector Machine for PEM Fuel-Cell Stack Aging Prediction
Abstract:
Proton exchange membrane fuel cells (PEMFCs) are considered as a potential candidate in the green-energy applications in the near future. Comparing with other energy options, the PEMFCs need only hydrogen and air during operation. Meanwhile, as a by-product during operation, water is produced. This energy-conversion process is 100% eco-friendly and completely unharmful to the environment. However, PEMFCs are vulnerable to the impurities of hydrogen or fluctuation of operational condition, which could cause the degradation of output performance over time during operation. Thus, the prediction of the performance degradation is critical to the PEMFC system. In this work, a novel PEMFC performance-forecasting model based on a modified relevance vector machine (RVM) has been proposed, followed by a comparison with the approach of classic support vector machine (SVM). First, the theoretical formulation of RVM is briefly introduced, then the implementation steps of RVM using the experimental aging data sets of PEMFC stack output voltage are presented. By considering the specific feature of aging data-prediction problem, an innovative modified RVM formulation is proposed. The results of proposed modified RVM method are analyzed and compared to the results of SVM. The results have demonstrated that the modified RVM can achieve better performance of prediction than SVM, especially in the cases with relatively small training data sets. This novel method based on modified RVM approach has been demonstrated to show its effectiveness on forecasting the performance degradation of PEMFCs.
Autors: Wu, Y.;Breaz, E.;Gao, F.;Miraoui, A.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jun 2016, volume: 52, issue:3, pages: 2573 - 2581
Publisher: IEEE
 
» A Motion Interference-Insensitive Flexible Dry Electrode
Abstract:
Objective: A novel dry electrode is developed to improve the comfortability and the capability of alleviating motion interference by combining microneedles array (MNA) with flexible substrate. Methods: Silicon MNA with sharp tips and limited height is fabricated and transferred on a flexible Polydimethylsiloxane (PDMS) substrate through bonding. Poly (3, 4-ethylenedioxythiophene) doped with poly (styrenesulfonate) (PEDOT/PSS) is coated on the surface of flexible MNA to form a conductive layer. Results: Flexible dry electrode with 1.2 cm diameter is successfully fabricated. The mean impedance magnitudes (measured on skin) at 10 Hz are kΩ·cm2 for flexible dry electrode, while the values are kΩ·cm2 for wet electrode and kΩ·cm2 for flexible planar dry electrode, respectively. In the process of biopotential recording, the flexible dry electrode has the similar performance as that of wet electrode. It exhibits more stable recording stability than rigid dry electrode in the movement state. Conclusion: By integrating flexible PDMS substrate, sharp and hard MNA structure, as well as PEDOT/PSS coated surface together, a novel dry electrode is developed to meet the comfortable and antimotion interference requirement of wearable equipment. Significance: The novel flexible dry electrode provides a simple and comfortable method to record biopotential signals in daily life.
Autors: Zhang, H.;Pei, W.;Chen, Y.;Guo, X.;Wu, X.;Yang, X.;Chen, H.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jun 2016, volume: 63, issue:6, pages: 1136 - 1144
Publisher: IEEE
 
» A Multi-State Optimization Framework for Parameter Estimation in Biological Systems
Abstract:
Parameter estimation is a key concern for reliable and predictive models of biological systems. In this paper, we propose a multi-objective, multi-state optimization framework that allows multiple data sources to be incorporated into the parameter estimation process. This enables the model to better represent a diverse range of data from both within and outwith the training set; and to determine more biologically relevant parameter values for the model parameters. The framework is based on a multi-objective PSwarm implementation (MoPSwarm) and is validated via a case study on the ERK signalling pathway, in which significant advantages over the conventional single-state approach are demonstrated. Several variants of the framework are analyzed to determine the optimal configuration for convergence and solution quality.
Autors: Gu, X.;
Appeared in: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Publication date: Jun 2016, volume: 13, issue:3, pages: 472 - 482
Publisher: IEEE
 
» A Multi-Task Learning Framework for Head Pose Estimation under Target Motion
Abstract:
Recently, head pose estimation (HPE) from low-resolution surveillance data has gained in importance. However, monocular and multi-view HPE approaches still work poorly under target motion, as facial appearance distorts owing to camera perspective and scale changes when a person moves around. To this end, we propose FEGA-MTL, a novel framework based on Multi-Task Learning (MTL) for classifying the head pose of a person who moves freely in an environment monitored by multiple, large field-of-view surveillance cameras. Upon partitioning the monitored scene into a dense uniform spatial grid, FEGA-MTL simultaneously clusters grid partitions into regions with similar facial appearance, while learning region-specific head pose classifiers. In the learning phase, guided by two graphs which a-priori model the similarity among (1) grid partitions based on camera geometry and (2) head pose classes, FEGA-MTL derives the optimal scene partitioning and associated pose classifiers. Upon determining the target's position using a person tracker at test time, the corresponding region-specific classifier is invoked for HPE. The FEGA-MTL framework naturally extends to a weakly supervised setting where the target's walking direction is employed as a proxy in lieu of head orientation. Experiments confirm that FEGA-MTL significantly outperforms competing single-task and multi-task learning methods in multi-view settings.
Autors: Yan, Y.;Ricci, E.;Subramanian, R.;Liu, G.;Lanz, O.;Sebe, N.;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Jun 2016, volume: 38, issue:6, pages: 1070 - 1083
Publisher: IEEE
 
» A Multi-view Learning Approach to Foreground Detection for Traffic Surveillance Applications
Abstract:
This paper proposes an effective multi-view learning approach to foreground detection for traffic surveillance applications. This approach involves three main steps. First, a reference background image is generated via temporal median filtering, and multiple heterogeneous features (including brightness variation, chromaticity variation, and texture variation, each of which represents a unique view) are extracted from the video sequence. Then, a multi-view learning strategy is devised to online estimate the conditional probability densities for both the foreground and the background. The probability densities of three features are approximately conditionally independent and are estimated with kernel density estimation. Pixel soft labeling is conducted by using Bayes rule, and the pixelwise foreground posteriors are computed. Finally, a Markov random field is constructed to incorporate the spatiotemporal context into the foreground/background decision model. The belief propagation algorithm is used to label each pixel of the current frame. Experimental results verify that the proposed approach is effective to detect foreground objects from challenging traffic environments and outperforms some state-of-the-art methods.
Autors: Wang, K.;Liu, Y.;Gou, C.;Wang, F.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jun 2016, volume: 65, issue:6, pages: 4144 - 4158
Publisher: IEEE
 
» A Multilevel Index Model to Expedite Web Service Discovery and Composition in Large-Scale Service Repositories
Abstract:
The number of web services has grown drastically. Then how to manage them efficiently in a service repository is an important issue to address. Given a special field, there often exists an efficient data structure for a class of objects, e.g., the Google’ Bigtable is very suitable for webpages’ storage and management. Based on the theory of the equivalence relations and quotient sets, this work proposes a multilevel index model for large-scale service repositories, which can be used to reduce the execution time of service discovery and composition. Its novel use of keys as inspired by the key in relational database can effectively remove the redundancy of the commonly-used inverted index. Its four function-based operations are for the first time proposed to manage and maintain services in a repository. The experiments validate that the proposed model is more efficient than the existing structures, i.e., sequential and inverted index ones.
Autors: Wu, Y.;Yan, Chun-Gang;Ding, Z.;Liu, G.;Wang, P.;Jiang, C.;Zhou, M.;
Appeared in: IEEE Transactions on Services Computing
Publication date: Jun 2016, volume: 9, issue:3, pages: 330 - 342
Publisher: IEEE
 
» A Multiobjective Approach to Find Optimal Electric-Vehicle Acceleration: Simultaneous Minimization of Acceleration Duration and Energy Consumption
Abstract:
The high energy consumption associated with acceleration requires electric vehicles (EVs) to accelerate to a chosen speed optimally, particularly in urban driving cycles. Existing methods deal with the minimization of acceleration energy without considering the acceleration duration. This paper focuses on solving a multiobjective optimization problem (MOOP) with two conflicting objectives: minimization of acceleration duration and minimization of energy consumption. Two approaches were used to reach a desired speed: using a single acceleration value and using multiple acceleration values. For each approach, demonstrative speed changes were chosen, and the problem was solved using multiobjective genetic algorithms (MOGAs). The results (Pareto-optimal fronts) obtained by these two approaches were compared using suitable performance metrics. To validate the reliability of MOGA results, statistical analysis was carried out. Furthermore, a nonparametric study, i.e., the Wilcoxon signed-rank test, was conducted to compare the effectiveness of both approaches. It was found that multiple accelerations were more effective in minimizing the duration and energy consumption than a single acceleration. For the same duration, multiple accelerations reduced energy consumption by up to 2%. Sensitivity analysis for both approaches with electric motor model parameters was conducted. The simulation results of EV acceleration using the preferred optimal solution based on driving comfort and the Pareto front's knee suggested a strong implication toward driving assistance.
Autors: Vaz, W.S.;Nandi, A.K.;Koylu, U.O.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jun 2016, volume: 65, issue:6, pages: 4633 - 4644
Publisher: IEEE
 
» A Multitasking Control Algorithm for Grid-Connected Inverters in Distributed Generation Applications Using Adaptive Noise Cancellation Filters
Abstract:
This paper proposes a multitasking control algorithm for grid-connected inverters (GCIs) in distributed generation (DG) applications. A single-phase H-bridge voltage source inverter is used as a power electronic interface between the DG system and the grid. The proposed control algorithm operates the GCI in current control mode to achieve desired active power injection to the grid. In addition to active power injection, the proposed control algorithm has current harmonics mitigation and reactive power compensation capabilities for power quality enhancement. The control algorithm utilizes only the remaining capacity of the GCI for power quality improvement. The proposed control algorithm employs a current decomposition structure based on multiple adaptive noise cancellation (ANC) filters for extraction of harmonic and reactive currents of the local loads. The extracted harmonics are used in estimating compensating currents to be injected by the GCI. A single-phase phase-locked loop (PLL) using ANC filters has been developed to synchronize the GCI at fundamental frequency, which makes the proposed control algorithm adaptive to grid frequency fluctuations and immune to grid voltage distortions. The effectiveness of the proposed control is illustrated through computer simulation and experimental results. The influence of PLL dynamics on GCI performance has also been studied using results.
Autors: Chilipi, R.R.;Al Sayari, N.;Beig, A.R.;Al Hosani, K.;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Jun 2016, volume: 31, issue:2, pages: 714 - 727
Publisher: IEEE
 
» A Multivariate Log-Linear Model for Birnbaum-Saunders Distributions
Abstract:
Univariate Birnbaum-Saunders models have been widely applied to fatigue studies. Calculation of fatigue life is of great importance in determining the reliability of materials. We propose and derive new multivariate generalized Birnbaum-Saunders regression models. We use the maximum likelihood method and the EM algorithm to estimate their parameters. We carry out a simulation study to evaluate the performance of the corresponding maximum likelihood estimators. We illustrate the new models with real-world multivariate fatigue data.
Autors: Marchant, C.;Leiva, V.;Cysneiros, F.J.A.;
Appeared in: IEEE Transactions on Reliability
Publication date: Jun 2016, volume: 65, issue:2, pages: 816 - 827
Publisher: IEEE
 
» A New Adaptive Sliding-Mode Control Scheme for Application to Robot Manipulators
Abstract:
This paper presents a new adaptive sliding-mode control (ASMC) scheme that uses the time-delay estimation (TDE) technique, then applies the scheme to robot manipulators. The proposed ASMC uses a new adaptive law to achieve good tracking performance with small chattering effect. The new adaptive law considers an arbitrarily small vicinity of the sliding manifold, in which the derivatives of the adaptive gains are inversely proportional to the sliding variables. Such an adaptive law provides remarkably fast adaptation and chattering reduction near the sliding manifold. To yield the desirable closed-loop poles and simplify a complicated system model by adapting feedback compensation, the proposed ASMC scheme works together with a pole-placement control (PPC) and a TDE technique. It is shown that the tracking errors of the proposed ASMC scheme are guaranteed to be uniformly ultimately bounded (UUB) with arbitrarily small bound. The practical effectiveness and the fast adaptation of the proposed ASMC are illustrated in simulations and experiments with robot manipulators, and compared with those of an existing ASMC.
Autors: Baek, J.;Jin, M.;Han, S.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jun 2016, volume: 63, issue:6, pages: 3628 - 3637
Publisher: IEEE
 
» A New Algorithm for Generating All Minimal Vectors for the SMPs Reliability Problem With Time and Budget Constraints
Abstract:
The quickest path reliability problem evaluates the probability of transmitting some given units of flow from a source node to a sink node through a single minimal path in a stochastic-flow network within some specified units of time. This problem has been recently extended to the case of transmitting flow through separate minimal paths (SMPs) simultaneously within a budget constraint. Here, we propose a new algorithm to solve such problems. The algorithm finds all the minimal vectors for which a given demand level units of flow can be transmitted through SMPs from a source node to a sink node satisfying some given time and budget limits. In our proposed algorithm, a special Diophantine system is needed to be solved, for which we provide a particularly efficient procedure with linear time complexity in terms of the number of its solutions. The complexity results are derived to demonstrate the efficiency of our proposed algorithm in comparison with others. To illustrate the practical efficiency of the algorithm, a network example is considered to compare our algorithm with a recently proposed one. Moreover, a comparative computational experiment is conducted on an extensive collection of random test problems using the performance profile of Dolan and Moré.
Autors: Forghani-elahabad, M.;Mahdavi-Amiri, N.;
Appeared in: IEEE Transactions on Reliability
Publication date: Jun 2016, volume: 65, issue:2, pages: 828 - 842
Publisher: IEEE
 
» A New Control Structure for Multiterminal DC Grids to Damp Interarea Oscillations
Abstract:
This paper analyzes the control structure of the multiterminal dc (MTDC) system to damp ac system interarea oscillations through active power modulation. A new control structure is presented that maximizes the relative controllability without the need for communication among the dc terminals. In point-to-point high-voltage dc (HVDC) transmission, the active power modulation of the two terminals occurs in opposite directions. In this case, the control direction is given and only needs to be phase compensated to align for maximal damping. In the case of MTDC systems, the control direction interrelates with the active power modulation share of the dc terminals and the relative controllability depends on this. The new control structure eliminates the need for communication between the dc terminals by performing dc voltage feedback loop shaping. This makes it possible to modulate the power in one terminal and let the other terminals react on the dc voltage change. Through loop shaping, where the feedback gain varies in the frequency plane compared to the regular droop design, the control direction is aligned with the direction of highest relative controllability. Loop shaping takes place without influencing the high frequency or steady-state gain. Simulations in the Nordic32 test system show the validity of the proposed controller and its structure.
Autors: Eriksson, R.;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Jun 2016, volume: 31, issue:3, pages: 990 - 998
Publisher: IEEE
 
» A New Cyclic-Prefix Based Algorithm for Blind CFO Estimation in OFDM Systems
Abstract:
In this paper, a new algorithm based on cyclic prefix (CP) is proposed for blind carrier frequency offset (CFO) estimation in orthogonal frequency division multiplexing (OFDM) transmission over multipath channels. Like other CP-based methods, the proposed method enjoys low complexity. The proposed method is very robust to the symbol timing synchronization error. Closed-form formulas for CFO estimates are derived. In addition, we also carry out the theoretical mean-square-error analysis and derive the Cramer-Rao bound. Simulation results show that the proposed method performs very well.
Autors: Lin, Tzu-Chiao;Phoong, See-May;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jun 2016, volume: 15, issue:6, pages: 3995 - 4008
Publisher: IEEE
 
» A New Fault-Location Algorithm for Extra-High-Voltage Mixed Lines Based on Phase Characteristics of the Hyperbolic Tangent Function
Abstract:
A new fault-location algorithm for extra-high-voltage mixed lines based on phase characteristics of the hyperbolic tangent function is proposed. This paper takes overhead-cable-overhead mixed lines for example. The faulted section identification functions for overhead cable connections described by the hyperbolic tangent are developed separately when faults occur on the first overhead line, the middle cable, and the last overhead line. When a fault occurs on different sections, the faulted section identification functions appear as obviously different phase characteristics according to the phase characteristics of the hyperbolic tangent function. Thus, the faulted section can be identified. The fault location can be therefore accurately determined with the voltage and current positive-sequence fault components on both ends of the faulted section. Simulations and calculations with PSCAD and MATALB show that the fault-location algorithm is correct and accurate.
Autors: Zhang, S.;Gao, H.;Song, Y.;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Jun 2016, volume: 31, issue:3, pages: 1203 - 1212
Publisher: IEEE
 
» A New Feature-Enhanced Speckle Reduction Method Based on Multiscale Analysis for Ultrasound B-Mode Imaging
Abstract:
Goal: Effective speckle reduction in ultrasound B-mode imaging is important for enhancing the image quality and improving the accuracy in image analysis and interpretation. In this paper, a new feature-enhanced speckle reduction (FESR) method based on multiscale analysis and feature enhancement filtering is proposed for ultrasound B-mode imaging. In FESR, clinical features (e.g., boundaries and borders of lesions) are selectively emphasized by edge, coherence, and contrast enhancement filtering from fine to coarse scales while simultaneously suppressing speckle development via robust diffusion filtering. In the simulation study, the proposed FESR method showed statistically significant improvements in edge preservation, mean structure similarity, speckle signal-to-noise ratio, and contrast-to-noise ratio (CNR) compared with other speckle reduction methods, e.g., oriented speckle reducing anisotropic diffusion (OSRAD), nonlinear multiscale wavelet diffusion (NMWD), the Laplacian pyramid-based nonlinear diffusion and shock filter (LPNDSF), and the Bayesian nonlocal means filter (OBNLM). Similarly, the FESR method outperformed the OSRAD, NMWD, LPNDSF, and OBNLM methods in terms of CNR, i.e., 10.70 ± 0.06 versus 9.00 ± 0.06, 9.78 ± 0.06, 8.67 ± 0.04, and 9.22 ± 0.06 in the phantom study, respectively. Reconstructed B-mode images that were developed using the five speckle reduction methods were reviewed by three radiologists for evaluation based on each radiologist's diagnostic preferences. All three radiologists showed a significant preference for the abdominal liver images obtained using the FESR methods in terms of conspicuity, margin sharpness, artificiality, and contrast, p<0.0001. For the kidney and thyroid images, the FESR method showed similar improvement over other methods. However, the FESR method did not show statistically significant improvement compared with the OBNLM method in m- rgin sharpness for the kidney and thyroid images. These results demonstrate that the proposed FESR method can improve the image quality of ultrasound B-mode imaging by enhancing the visualization of lesion features while effectively suppressing speckle noise.
Autors: Kang, J.;Lee, J.Y.;Yoo, Y.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jun 2016, volume: 63, issue:6, pages: 1178 - 1191
Publisher: IEEE
 
» A New Mobile Platform (RHyMo) for Smooth Movement on Rugged Terrain
Abstract:
This paper suggests a new performance metric for a mobile platform called as a posture variation index (PVI) to evaluate the smoothness of its movement, which is an important factor to predict undesired oscillations or shocks on a mobile platform while traveling on rugged terrain. The PVI consists of the height and pitch angle variations of center of mass of a mobile platform. By using the PVI, the movements of well-known mobile platforms are systematically analyzed. In order to ensure smooth movement as well as high terrainability on rugged terrain, a new mobile platform (RHyMo) is constructed on the basis of the kinematic and quasi-static analyses. The extensive experiments are carried out by using the RHyMo and the Rocker-Bogie platform on the artificial rugged terrain, which verify that in comparison with the Rocker-Bogie platform, the average and maximum height variations of RHyMo are reduced by 12.72% and 5.96%, respectively. Moreover, the average and maximum pitch angle variations of RHyMo are significantly reduced by 65.87% and 60.53%, respectively. The terrainability of RHyMo against a high step and steep stairs is improved with the help of the track mechanism installed in the front linkage.
Autors: Choi, D.;Kim, Y.;Jung, S.;Kim, J.;Kim, H.S.;
Appeared in: IEEE/ASME Transactions on Mechatronics
Publication date: Jun 2016, volume: 21, issue:3, pages: 1303 - 1314
Publisher: IEEE
 
» A New Model of Electromechanical Relays for Predicting the Motion and Electromagnetic Dynamics
Abstract:
In this paper, a novel multiphysics and nonlinear model for electromechanical relays is presented. The electromagnetic dynamics is analyzed by calculating the total reluctance of the magnetic equivalent circuit (MEC), which is composed of a fixed length iron core and an angular air gap. Magnetic saturation and angular dependency of the reluctance are considered in the analysis. Then, an energy balance over the electromagnetic components of the system is used to obtain the torque which drives the movable armature. A planar mechanism of four rigid bodies, including spring-damping torques that restrict the motion and model the contact bounces that occur in the switchings, is proposed to explain the dynamics of the movable components. Experimental tests show the accuracy of the model in both the electromagnetic and the mechanical parts.
Autors: Ramirez-Laboreo, E.;Sagues, C.;Llorente, S.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jun 2016, volume: 52, issue:3, pages: 2545 - 2553
Publisher: IEEE
 

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