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Electrical and Electronics Engineering publications abstract of: 02-2015 sorted by title, page: 0
» (Co)content in Circuits With Memristive Elements
Abstract:
The paper deals with the extension of the concept of content and cocontent functions, known from the theory of nonlinear resistive circuits, to circuits with memristive elements. The connection between the (co)content and the area of the hysteresis loop of a memristive element is indicated. It is proved and demonstrated on examples that the area of the hysteresis loop of a one-port, composed entirely of memristive elements, equals the sum of the areas of the loops of individual memristive elements. It is also proved that the law of conservation of (co)content applies also to circuits with memristive elements.
Autors: Biolek, Z.;Biolek, D.;Biolkova, V.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Feb 2015, volume: 62, issue:2, pages: 488 - 496
Publisher: IEEE
 
» 110 W All Fiber Actively Q-Switched Thulium-Doped Fiber Laser
Abstract:
We report a 100-W-level, repetition rate and pulsewidth tunable, all-fiber, thulium-doped master oscillator power amplifier system. The master oscillator was actively Q-switched by a fiber-coupled acousto-optic modulator. The generated pulsewidth could be tuned from 1.16 to 46.3 ns by adjusting modulation repetition rate from 1 kHz to 2 MHz, and the pulse repetition rate (PRR) can also be tuned from 1 kHz to 2 MHz, correspondingly. The maximum output power could be boosted to 110 W (slope efficiency of 55%) through three-stage thulium-doped fiber (TDF) amplifiers at PRR from 100 kHz to 2 MHz. The spectrum bandwidth was about 0.8 nm at the maximum output power without obvious indication of nonlinear effects. To the best of our knowledge, this is the first demonstration of 110-W, all-fiber, actively Q-switched TDF laser, and it has realized the largest tuning ranges both with the pulsewidth and the PRR.
Autors: Ouyang, D.;Zhao, J.;Zheng, Z.;Ruan, S.;Guo, C.;Yan, P.;Xie, W.;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2015, volume: 7, issue:1, pages: 1 - 6
Publisher: IEEE
 
» 1D-3D Registration for Intra-Operative Nuclear Imaging in Radio-Guided Surgery
Abstract:
3D functional nuclear imaging modalities like SPECT or PET provide valuable information, as small structures can be marked with radioactive tracers to be localized before surgery. This positional information is valuable during surgery as well, for example when locating potentially cancerous lymph nodes in the case of breast cancer. However, the volumetric information provided by pre-operative SPECT scans loses validity quickly due to posture changes and manipulation of the soft tissue during surgery. During the intervention, the surgeon has to rely on the acoustic feedback provided by handheld gamma-detectors in order to localize the marked structures. In this paper, we present a method that allows updating the pre-operative image with a very limited number of tracked readings. A previously acquired 3D functional volume serves as prior knowledge and a limited number of new 1D detector readings is used in order to update the prior knowledge. This update is performed by a 1D-3D registration algorithm that registers the volume to the detector readings. This enables the rapid update of the visual guidance provided to the surgeon during a radio-guided surgery without slowing down the surgical workflow. We evaluate the performance of this approach using Monte-Carlo simulations, phantom experiments and patient data, resulting in a positional error of less than 8 mm which is acceptable for surgery. The 1D-3D registration is also compared to a volumetric reconstruction using the tracked detector measurements without taking prior information into account, and achieves a comparable accuracy with significantly less measurements.
Autors: Vetter, C.;Lasser, T.;Okur, A.;Navab, N.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Feb 2015, volume: 34, issue:2, pages: 608 - 617
Publisher: IEEE
 
» 2014 MTT Society Awards [Awards]
Abstract:
Lists the recipients of 2014 MTT Society awards.
Autors: Jackson, C.;
Appeared in: IEEE Microwave Magazine
Publication date: Feb 2015, volume: 16, issue:1, pages: 144 - 145
Publisher: IEEE
 
» 2014 Reviewers
Abstract:
Lists the reviewers who contributed to IEEE Software in 2014.
Autors: null;
Appeared in: IEEE Software
Publication date: Feb 2015, volume: 32, issue:1, pages: 8 - 10
Publisher: IEEE
 
» 2015 IEEE CIS Awards [Society Briefs]
Abstract:
Lists the recipients of 2015 IEEE CIS awards.
Autors: Yen, G.;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Feb 2015, volume: 10, issue:1, pages: 6 - 10
Publisher: IEEE
 
» 3-D Distributed Memory Polynomial Behavioral Model for Concurrent Dual-Band Envelope Tracking Power Amplifier Linearization
Abstract:
This paper presents a new 3-D behavioral model to compensate for the nonlinear distortion arising in concurrent dual-band (DB) Envelope Tracking (ET) Power Amplifiers (PAs). The advantage of the proposed 3-D distributed memory polynomial (3D-DMP) behavioral model, in comparison to the already published behavioral models used for concurrent dual-band envelope tracking PA linearization, is that it requires a smaller number of coefficients to achieve the same linearity performance, which reduces the overall identification and adaptation computational complexity. The proposed 3D-DMP digital predistorter (DPD) is tested under different ET supply modulation techniques. Moreover, further model order reduction of the 3D-DMP DPD is achieved by applying the principal component analysis (PCA) technique. Experimental results are shown considering a concurrent DB transmission of a WCDMA signal at 1.75 GHz and a 10-MHz bandwidth LTE signal at 2.1 GHz. The performance of the proposed 3D-DMP DPD is evaluated in terms of linearity, drain power efficiency, and computational complexity.
Autors: Gilabert, P.L.;Montoro, G.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Feb 2015, volume: 63, issue:2, pages: 638 - 648
Publisher: IEEE
 
» 320-Channel Active Probe for High-Resolution Neuromonitoring and Responsive Neurostimulation
Abstract:
We present a 320-channel active probe for high-spatial-resolution neuromonitoring and responsive neurostimulation. The probe comprises an integrated circuit (IC) cell array bonded to the back side of a pitch-matched microelectrode array. The IC enables up to 256-site neural recording and 64-site neural stimulation at the spatial resolution of 400 m and 200 m, respectively. It is suitable for direct integration with electrode arrays with the shank pitch of integer multiples of 200 m. In the presented configuration, the IC is bonded with a 8 8 400 m-pitch Utah electrode array (UEA) and up to additional 192 recording channels are used for peripheral neuromonitoring. The 0.35 m CMOS circuit array has a total die size of 3.5 mm 3.65 mm. Each stimulator channel employs a current memory for simultaneous multi-site neurostimulation, outputs 20 A–250 A square or arbitrary waveform current, occupies 0.02 mm , and dissipates 2.76 W quiescent power. Each fully differential recording channel has two stages of amplification and filtering and an 8-bit single-slope ADC, occupies 0.035 mm , and consumes 51.9 $mu$ W. The neural probe has been experimentally validated in epileptic seizure propagation studies in a mouse hippocampal slice in vitro and in responsive neurostimulation for seizure suppression in an acute epilepsy rat model in vivo .
Autors: Shulyzki, R.;Abdelhalim, K.;Bagheri, A.;Salam, M.T.;Florez, C.M.;Velazquez, J.L.P.;Carlen, P.L.;Genov, R.;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Feb 2015, volume: 9, issue:1, pages: 34 - 49
Publisher: IEEE
 
» 37-GHz Modulation via Resonance Tuning in Single-Mode Coherent Vertical-Cavity Laser Arrays
Abstract:
We show a significant improvement of modulation bandwidth from photonic crystal vertical-cavity surface-emitting laser arrays. Control of injection bias conditions to array elements enables resonance tuning of each element with variation of the phase relation and coherence of the array, resulting in the ability to tailor the modulation response. A bandwidth of 37 GHz is obtained under highly single-mode coherent operation with narrow spectral width and increased output power while the laser array is biased at low current density. Lasers with such performance characteristics may greatly enhance high-rate data transfer in computer server, data center, and supercomputer applications with potentially long device lifetime.
Autors: Fryslie, S.T.M.;Siriani, M.P.T.;Siriani, D.F.;Johnson, M.T.;Choquette, K.D.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Feb 2015, volume: 27, issue:4, pages: 415 - 418
Publisher: IEEE
 
» 3D elastic optical networking in the temporal, spectral, and spatial domains
Abstract:
Conventional elastic optical networking, EON, uses elasticity in two domains, time and frequency, to optimize utilization of optical network resources in the presence of fluctuating traffic demand and link quality. Currently, networking exploiting a third domain, space, is the focus of significant research efforts since space-division multiplexing, SDM, has the potential to substantially improve future network capacity and spectral efficiency. This article extends 2D-EON to include elasticity in all three domains: time, frequency, and space. We introduce enabling technologies, architectures, and algorithms for 3D-EONs. Based on sample network topologies, we investigate algorithms for routing, spectrum, spatial mode, and modulation format assignment ??? RSSMA. In particular, we investigate fragmentation-aware RSSMA and how the constraints in the formation of super-channels in MIMO-based SDM systems can impact the network performance in terms of blocking probability.
Autors: Proietti, Roberto;Liu, Lei;Scott, Ryan P.;Guan, Binbin;Qin, Chuan;Su, Tiehui;Giannone, Francesco;Yoo, S.J.B.;
Appeared in: IEEE Communications Magazine
Publication date: Feb 2015, volume: 53, issue:2, pages: 79 - 87
Publisher: IEEE
 
» 4×25 Gb/s Transceiver With Optical Front-end for 100 GbE System in 65 nm CMOS Technology
Abstract:
This paper presents a fully-integrated chipset for 4×25 Gb/s transceiver gearbox along with laser driver and photo detector front-ends. The transceiver provides 10:4 multiplexing and 4:10 demultiplexing conversion, with built-in clock generation, equalization, and amplification. The optical front-ends are realized as 4-element arrays, presenting remarkable performance with commercial vertical-cavity surface-emitting lasers and photodiodes. Feedforward equalizers and continuous-time linear equalizers are employed to compensate for loss and distortion in both electrical and optical domains. Fabricated in 65 nm CMOS technology, these chips can be lumped together as a compact module with performance exceeding typical 100 GbE standards.
Autors: Chiang, P.-C.;Jiang, J.-Y.;Hung, H.-W.;Wu, C.-Y.;Chen, G.-S.;Lee, J.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2015, volume: 50, issue:2, pages: 573 - 585
Publisher: IEEE
 
» 40 Gb/s PAM-4 Transmitter IC for Long-Wavelength VCSEL Links
Abstract:
Conventional 850 nm multimode fiber links deployed in warehouse-scale data centers will be limited by modal dispersion beyond 10 Gb/s when covering distances up to 1 km. This can be resolved by opting for a single-mode fiber (SMF), but typically requires the use of power-hungry edge-emitting lasers. We investigate the feasibility of a high-efficiency SMF link by reporting a 0.13 SiGe BiCMOS laser diode driver optimized for long-wavelength vertical-cavity surface-emitting lasers (VCSELs). Bit-error rate experiments at 28 and 40 Gb/s up to 1 km of SMF reveal that four-level pulse amplitude modulation can compete with non-return-to-zero in terms of energy efficiency and scalability. With 9.4 pJ/b, the presented transmitter paves the way for VCSEL-based SMF links in data centers.
Autors: Soenen, W.;Vaernewyck, R.;Yin, X.;Spiga, S.;Amann, M.;Kaur, K.S.;Bakopoulos, P.;Bauwelinck, J.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Feb 2015, volume: 27, issue:4, pages: 344 - 347
Publisher: IEEE
 
» 400 Gigabit Ethernet using advanced modulation formats: Performance, complexity, and power dissipation
Abstract:
We review possible architectures for 400 Gigabit Ethernet links based on advanced modulation formats for the first time. Their optical link power budget, digital complexity, and power dissipation are compared via simulations. The challenges of implementing the physical layer are discussed.
Autors: Wei, Jinlong;Cheng, Qixiang;Penty, Richard V.;White, Ian H.;Cunningham, David G.;
Appeared in: IEEE Communications Magazine
Publication date: Feb 2015, volume: 53, issue:2, pages: 182 - 189
Publisher: IEEE
 
» 4H-SiC Piezoresistive Pressure Sensors at 800 °C With Observed Sensitivity Recovery
Abstract:
Uncooled MEMS-based 4H-SiC Wheatstone bridge configured piezoresistive pressure sensors were demonstrated from 23 °C to 800 °C. The full-scale output (FSO) voltage exhibited gradual decrease with increasing temperature from 23 °C to 400 °C, then swung upward as temperature increased further to where the values measured at 800 °C were nearly equal to or higher than the room temperature values. This newly observed FSO behavior in 4H-SiC contrasts sharply with the FSO behavior of silicon piezoresistive sensors that decrease continuously with increasing temperature. The increase in the sensor output sensitivity at 800 °C implies higher signal to noise ratio and improved fidelity, thereby offering promise of further insertion into >600 °C environments without the need for cooling and complex signal conditioning.
Autors: Okojie, R.S.;Lukco, D.;Nguyen, V.;Savrun, E.;
Appeared in: IEEE Electron Device Letters
Publication date: Feb 2015, volume: 36, issue:2, pages: 174 - 176
Publisher: IEEE
 
» 5.8-kV Implantation-Free 4H-SiC BJT With Multiple-Shallow-Trench Junction Termination Extension
Abstract:
Implantation-free 4H-SiC bipolar junction transistors with multiple-shallow-trench junction termination extension have been fabricated. The maximum current gain of 40 at a current density of 370 A/ is obtained for the device with an active area of 0.065 . A maximum open-base breakdown voltage (BV) of 5.85 kV is measured, which is 93% of the theoretical BV. A specific on-resistance ( ) of 28 m was obtained.
Autors: Elahipanah, H.;Salemi, A.;Zetterling, C.;Ostling, M.;
Appeared in: IEEE Electron Device Letters
Publication date: Feb 2015, volume: 36, issue:2, pages: 168 - 170
Publisher: IEEE
 
» 5th generation mobile networks: A new opportunity for the convergence of mobile broadband and broadcast services
Abstract:
This article analyzes the challenges and opportunities that the upcoming definition of future 5G mobile networks brings to the mobile broadband and broadcast industries to form a single converged network. It reviews the state-of-the-art in mobile and broadcast technologies and the current trends for convergence between both industries. This article describes the requirements and functionalities that the future 5G must address in order to make an efficient and flexible cellular-broadcasting convergence. Both industries would benefit from this convergence by exploiting synergies and enabling an optimum use of spectrum based on coordinated spectrum sharing.
Autors: Calabuig, Jordi;Monserrat, Jose F.;Gomez-Barquero, David;
Appeared in: IEEE Communications Magazine
Publication date: Feb 2015, volume: 53, issue:2, pages: 198 - 205
Publisher: IEEE
 
» per Channel Analog Biomimetic Cochlear Implant Processor Filterbank Architecture With Across Channels AGC
Abstract:
A new analog cochlear implant processor filterbank architecture of increased biofidelity, enhanced across-channel contrast and very low power consumption has been designed and prototyped. Each channel implements a biomimetic, asymmetric bandpass-like One-Zero-Gammatone-Filter (OZGF) transfer function, using class-AB log-domain techniques. Each channel's quality factor and suppression are controlled by means of a new low power Automatic Gain Control (AGC) scheme which is coupled across the neighboring channels and emulates lateral inhibition (LI) phenomena in the auditory system. Detailed measurements from a five-channel silicon IC prototype fabricated in a AMS technology confirm the operation of the coupled AGC scheme and its ability to enhance contrast among channel outputs. The prototype is characterized by an input dynamic range of 92 dB while consuming only of power in total ( per channel) under a 1.8 V power supply. The architecture is well-suited for fully-implantable cochlear implants.
Autors: Yang, G.;Lyon, R.F.;Drakakis, E.M.;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Feb 2015, volume: 9, issue:1, pages: 72 - 86
Publisher: IEEE
 
» Optical Orthogonal Signature Pattern Codes With Maximum Possible Size
Abstract:
Kitayama proposed a novel code-division multiple-access (CDMA) network for image transmission called spatial CDMA. Optical orthogonal signature pattern codes (OOSPCs) have attracted wide attention as signature patterns of spatial CDMA. An -OOSPC is a set of -matrices with Hamming weight and maximum correlation value . Let be the largest possible number of codewords among all -OOSPCs. In this paper, we concentrate on the calculation of the exact value of and the construction of an -OOSPC with codewords. As a consequence, we show that when , or and , or and , and- otherwise.
Autors: Pan, R.;Chang, Y.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Feb 2015, volume: 61, issue:2, pages: 1139 - 1148
Publisher: IEEE
 
» Noise Expressions for Amorphous InGaZnO TFTs Considering Mobility Power-Law Parameter in Above-Threshold Regime
Abstract:
Analytical noise expressions are presented for amorphous InGaZnO thin-film transistors considering the well-known power-law parameter in the mobility equation. The drain current noise power spectral density (PSD) is derived from Ghibaudo’s carrier number fluctuation model. It is found that the parameter clarifies the relationship between the drain current noise PSD and the drain current. The relationship is verified by the available experimental data.
Autors: He, H.;Zheng, X.;Zhang, S.;
Appeared in: IEEE Electron Device Letters
Publication date: Feb 2015, volume: 36, issue:2, pages: 156 - 158
Publisher: IEEE
 
» Controller Design for Preview and Delayed Systems
Abstract:
The control problem of general preview/delayed systems is solved using analytic solutions of the corresponding operator Riccati equations. The solution to the problem can be applied to a broad range of input/output delayed systems and enables the handling of preview/delayed control problems. The solvability condition is characterized by the roots of the transcendental equations and the control law for the general problem is given based on a predictive compensation with an integro-differential observer. Some interpretations of typical control problems are presented based on the solvability condition and the resulting control law.
Autors: Kojima, A.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Feb 2015, volume: 60, issue:2, pages: 404 - 419
Publisher: IEEE
 
» In Vivo Irreversible Electroporation Kidney Ablation: Experimentally Correlated Numerical Models
Abstract:
Irreversible electroporation (IRE) ablation uses brief electric pulses to kill a volume of tissue without damaging the structures contraindicated for surgical resection or thermal ablation, including blood vessels and ureters. IRE offers a targeted nephron-sparing approach for treating kidney tumors, but the relevant organ-specific electrical properties and cellular susceptibility to IRE electric pulses remain to be characterized. Here, a pulse protocol of 100 electric pulses, each 100 μs long, is delivered at 1 pulse/s to canine kidneys at three different voltage-to-distance ratios while measuring intrapulse current, completed 6 h before humane euthanasia. Numerical models were correlated with lesions and electrical measurements to determine electrical conductivity behavior and lethal electric field threshold. Three methods for modeling tissue response to the pulses were investigated (static, linear dynamic, and asymmetrical sigmoid dynamic), where the asymmetrical sigmoid dynamic conductivity function most accurately and precisely matched lesion dimensions, with a lethal electric field threshold of 575 ± 67 V/cm for the protocols used. The linear dynamic model also attains accurate predictions with a simpler function. These findings can aid renal IRE treatment planning under varying electrode geometries and pulse strengths. Histology showed a wholly necrotic core lesion at the highest electric fields, surrounded by a transitional perimeter of differential tissue viability dependent on renal structure.
Autors: Neal, R.E.;Garcia, P.A.;Kavnoudias, H.;Rosenfeldt, F.;Mclean, C.A.;Earl, V.;Bergman, J.;Davalos, R.V.;Thomson, K.R.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Feb 2015, volume: 62, issue:2, pages: 561 - 569
Publisher: IEEE
 
» In Vivo Ultrasound Thermography in Presence of Temperature Heterogeneity and Natural Motions
Abstract:
Real-time ultrasound thermography has been recently demonstrated on commercially available diagnostic imaging probes. In vitro experimental results demonstrate high sensitivity to small, localized temperature changes induced by subtherapeutic focused ultrasound. Most of the published results, however, are based on a thermally induced echo strain model that assumes infinitesimal change in temperature between imaging frames. Under this assumption, the echo strain is computed using a low-pass axial differentiator, which is implemented by a finite-impulse response digital filter. In this paper, we introduce a new model for temperature estimation, which employs a recursive axial filter that acts as a spatial differentiator–integrator of echo shifts. The filter is derived from first principles and it accounts for a nonuniform temperature baseline, when computing the spatial temperature change between two frames. This is a major difference from the previously proposed infinitesimal echo strain filter ( -ESF) approach. We show that the new approach can be implemented by a first-order infinite-impulse response digital filter with depth-dependent spatial frequency response. Experimental results in vitro demonstrate the advantages over the -ESF approach in terms of suppressing the spatial variations in the estimated temperature without resorting to ad hoc low-pass filtering of echo strains. The performance of the new recursive echo strain filter (RESF) is also illustrated using echo data obtained during subtherapeutic localized heating in the hind limb of Copenhagen rat in vivo. In addition to the RESF, we have used an adaptive spatial filter to remove motion and deformation artifacts during real-time data collection. The adaptive filtering algorithm is described - nd comparisons with uncompensated estimated spatio-temporal temperature profiles are given. The results demonstrate the feasibility of in vivo ultrasound thermography with high sensitivity and specificity.
Autors: Bayat, M.;Ballard, J.R.;Ebbini, E.S.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Feb 2015, volume: 62, issue:2, pages: 450 - 457
Publisher: IEEE
 
» A "Design First" Approach to Visualization Innovation
Abstract:
The design-first approach focuses on the initial design of a visualization without the overhead of data and system requirements. Two case studies that used this technique show how a nontechnical approach can be successful at eliciting thought-provoking visualization solutions without the need for sample data.
Autors: Paul, Celeste Lyn;Rohrer, Randall;Nebesh, Bohdan;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Feb 2015, volume: 35, issue:1, pages: 12 - 18
Publisher: IEEE
 
» A 0.15 V Input Energy Harvesting Charge Pump With Dynamic Body Biasing and Adaptive Dead-Time for Efficiency Improvement
Abstract:
A charge pump using 0.13- m CMOS process for low-voltage energy harvesting is presented. A low-power adaptive dead-time (AD) circuit is used which automatically optimizes the dead-time according to the input voltage. A negative charge pump is also utilized for high efficiency at low input voltages . The AD circuit improves efficiency by 17% at of 0.2 V compared to the fixed dead time circuit as well as enables the charge pump to work at down to 0.15 V. Dynamic body bias (DBB) and switch-conductance enhancement techniques are applied to a unit stage of the three-stage charge pump. The reverse current flowing through the cross-coupled NMOS switches is prevented and the current transfer is also maximized. Together with the AD circuit and the DBB technique, the maximum output current was improved by 240% as compared to the conventional charge pump design using only the forward body bias.
Autors: Kim, J.;Mok, P.K.T.;Kim, C.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2015, volume: 50, issue:2, pages: 414 - 425
Publisher: IEEE
 
» A 0.8-V, 1-MS/s, 10-bit SAR ADC for Multi-Channel Neural Recording
Abstract:
This paper presents a 10-bit single-ended SAR ADC suitable for multi-channel neural recording. The proposed ADC introduces several power saving techniques to boost the energy efficiency. The ADC is built with on-chip common-mode buffer for input tracking, which is reused as the pre-amplifier of a current-mode comparator during conversion. A small capacitor is inserted between the amplifier and the capacitive DAC array in order to reduce the capacitive load on the amplifier. A split capacitor array with dual thermometer decoders is proposed to reduce the switching energy. Implemented in 0.13- CMOS technology, the ADC achieved a maximum differential nonlinearity (DNL) of 0.33/ 0.56 LSB, maximum integral nonlinearity (INL) of 0.61/ 0.55 LSB, effective number-of-bits (ENOB) of 8.8, and a power consumption of 9- .
Autors: Tao, Y.;Lian, Y.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Feb 2015, volume: 62, issue:2, pages: 366 - 375
Publisher: IEEE
 
» A 0.87 W Transceiver IC for 100 Gigabit Ethernet in 40 nm CMOS
Abstract:
This paper describes a low-power 100 Gigabit Ethernet transceiver IC compliant with IEEE802.3ba 100GBASE-LR4 in 40 nm CMOS. The proposed bidirectional full-duplex transceiver IC contains a total of eight 28 Gb/s CDRs. Each CDR lane incorporates phase-rotator-based delay- and phase-locked loop (D/PLL) architecture for enhanced jitter filtering. All the CDR lanes operate independently while sharing a single voltage-controlled oscillator and supporting referenceless clock acquisition. To reduce power consumption, a multidrop clock distribution scheme with single on-chip transmission-line (T-line) and quadrate RX and TX schemes without CML logic gates are incorporated. Embedded built-in self-test modules featuring a random accumulation jitter generator enables bit error rate (BER) and jitter tolerance self tests without any external equipment. The TX featuring a three-tap pre-emphasis provides a variable output swing ranging from 478 mV to 1.06 V . RX equalizers employing a continuous-time linear equalizer and a one-tap decision feedback equalizer compensate for the channel loss up to 25 dB at the Nyquist rate. The measured RX input sensitivity for a BER of 10 is 42 mV . The proposed IC consumes only 0.87 W at 28.0 Gb/s with a BER less than 10 on PRBS31 testing. The power efficiency of the proposed transceiver is 3.9 mW/Gb/s, which is the best among the efficiencies achieved by recently published 25 Gb/s transceivers.
Autors: Won, H.;Yoon, T.;Han, J.;Lee, J.-Y.;Yoon, J.-H.;Kim, T.;Lee, J.-S.;Lee, S.;Han, K.;Lee, J.;Park, J.;Bae, H.-M.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2015, volume: 50, issue:2, pages: 399 - 413
Publisher: IEEE
 
» A 13.56-Mbps Pulse Delay Modulation Based Transceiver for Simultaneous Near-Field Data and Power Transmission
Abstract:
A fully-integrated near-field wireless transceiver has been presented for simultaneous data and power transmission across inductive links, which operates based on pulse delay modulation (PDM) technique. PDM is a low-power carrier-less modulation scheme that offers wide bandwidth along with robustness against strong power carrier interference, which makes it suitable for implantable neuroprosthetic devices, such as retinal implants. To transmit each bit, a pattern of narrow pulses are generated at the same frequency of the power carrier across the transmitter (Tx) data coil with specific time delays to initiate decaying ringing across the tuned receiver (Rx) data coil. This ringing shifts the zero-crossing times of the undesired power carrier interference on the Rx data coil, resulting in a phase shift between the signals across Rx power and data coils, from which the data bit stream can be recovered. A PDM transceiver prototype was fabricated in a 0.35- standard CMOS process, occupying 1.6 . The transceiver achieved a measured 13.56 Mbps data rate with a raw bit error rate (BER) of at 10 mm distance between figure-8 data coils, despite a signal-to-interference ratio (SIR) of 18.5 dB across the Rx data coil. At the same time, a class-D power amplifier, operating at 13.56 MHz, delivered 42 mW of regulated power across a separate pair of high-Q power coils, aligned with the data coils. The PDM data Tx and Rx power consumptions were 960 pJ/bit and 162 pJ/bit, respectively, at 1.8 V supply voltage.
Autors: Kiani, M.;Ghovanloo, M.;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Feb 2015, volume: 9, issue:1, pages: 1 - 11
Publisher: IEEE
 
» A 180-Vpp Integrated Linear Amplifier for Ultrasonic Imaging Applications in a High-Voltage CMOS SOI Technology
Abstract:
This brief presents a monolithically integrated fully differential linear HV amplifier as the driver of an ultrasonic transducer. The linear amplifier is capable of transmitting HV arbitrary signals with a very low harmonic distortion, which is suitable for tissue harmonic imaging and other ultrasonic modes for enhanced imaging quality. The amplifier is designed and implemented using the 0.7- CMOS silicon-on-insulator process with 120-V devices. The amplifier, when driving a load of 300 pF in parallel with 100 Ω, is capable of transmitting a sine-wave signal with a frequency of up to 4.4 MHz, a maximum signal swing of 180 Vpp, and a second-order harmonic distortion (HD2) of 56 dBc but only dissipating an average power of 62 mW with a 0.1% duty cycle.
Autors: Sun, K.;Gao, Z.;Gui, P.;Wang, R.;Oguzman, I.;Xu, X.;Vasanth, K.;Zhou, Q.;Shung, K.K.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Feb 2015, volume: 62, issue:2, pages: 149 - 153
Publisher: IEEE
 
» A 2–16 GHz 65 nm CMOS Stepped-Frequency Radar Transmitter With Harmonic Rejection for High-Resolution Medical Imaging Applications
Abstract:
A 65 nm CMOS transmitter capable of providing signals over the wide 2 to 16 GHz frequency range for stepped-frequency continuous wave short-range medical radar applications is presented. It generates both the local oscillator signals required for quadrature downconversion in the receiver path, and the transmitter output signal, thus guaranteeing phase coherence between transmitter and receiver, essential requirement for correct radar operation. Made of a 6.5 to 18.4GHz PLL, an inductorless injection-locked programmable divider by 1, 2, or 4, and a harmonic rejection buffer, it features an average output power of 14 dBm, a phase noise at 10 MHz offset 129 dBc/Hz, a RMS jitter 0.68 ps, a reference spur level 48 dBc, a harmonic rejection 40 dBc, and a settling time of 2 .
Autors: Caruso, M.;Bassi, M.;Bevilacqua, A.;Neviani, A.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Feb 2015, volume: 62, issue:2, pages: 413 - 422
Publisher: IEEE
 
» A 2.2 mW, 40 dB Automatic Gain Controllable Low Noise Amplifier for FM Receiver
Abstract:
This paper presents an automatic gain controllable low noise amplifier (AGC-LNA) for FM receiver (FMRx). The proposed LNA adopts current reused dual -boosting technique for the power saving. And, a simple analog type automatic gain control (AGC) loop is proposed that provides high resolution gain control. Implemented in a 65 nm CMOS technology, measurements show power regulation range of 40 dB with 1 dB error, less than 11 dB of S11, variable voltage gain range of 12 to 30 dB over the frequency range of 88 108 MHz, noise figure (NF) of less than 2.9 dB, P1dB of higher than 24.2 dBm, and IIP3 of higher than 12.7 dBm in the high gain (HG) mode, while dissipating only 1.8 mA from a 1.2 V supply, respectively.
Autors: Jeong, C.-J.;Sun, Y.;Han, S.-K.;Lee, S.-G.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Feb 2015, volume: 62, issue:2, pages: 600 - 606
Publisher: IEEE
 
» A 20-km/60-Gb/s Two-Way PON Based on Directly Modulated Two-Stage Injection-Locked 1.55- VCSEL Transmitters and Negative Dispersion Fibers
Abstract:
A 20-km/60-Gb/s two-way passive optical network (PON) based on directly modulated two-stage injection-locked 1.55- vertical-cavity surface-emitting laser (VCSEL) transmitters and negative dispersion fibers (NDFs) is proposed and demonstrated. A one-stage injection-locked technique has been confirmed as an effective approach for increasing the frequency response of a VCSEL. A two-stage injection-locked technique, which can further increase the frequency response of a VCSEL, is thereby expected to have excellent transmission performance in a two-way PON. To be the first to employ directly modulated two-stage injection-locked 1.55- VCSEL transmitters in a two-way PON, brilliant bit-error-rate performance and a clear eye diagram are obtained over a 20-km NDF transport. A directly modulated VCSEL has a positive chirp, whereas an NDF has a negative dispersion property in the transmission fiber; this negative dispersion property compensates the laser positive chirp and results in systems with better transmission performance. Such an innovative two-way PON provides the advantage of a communication link for high data rates, which is an attractive feature that is useful for broadband network applications.
Autors: Ying, C.;Lu, H.;Li, C.;Lin, C.;Lin, C.;Peng, P.;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2015, volume: 7, issue:1, pages: 1 - 9
Publisher: IEEE
 
» A 24–44 GHz Broadband Subharmonic Mixer With Novel Isolation-Enhanced Circuit
Abstract:
A 24 to 44 GHz upconversion broadband subharmonic mixer with a novel isolation-enhanced architecture is presented through a 0.15 m GaAs pHEMT process. Total chip size including probe pads is less than 1.33 0.82 mm . The isolation-enhanced circuit is constructed from two directional couple lines both formed with three microstrip lines. They are used to enhance the isolation between IF/LO-to-RF and LO-to-IF. IF and RF pre-amplifiers are employed to achieve high conversion gain for subharmonic mixing of anti-parallel diode pairs. Based on the unilateral characteristics of an IF pre-amplifier, the LO/RF-to-IF isolations exhibit substantial improvement. From the measured results, the conversion gain of the mixer is 6.0 to 10.5 dB operating at RF frequency of 24 to 44 GHz. The IF-to-RF, LO-to-IF, LO-to-RF, and 2LO-to-RF isolations are 24.5 to 27.1 dB, 32.4 to 39.6 dB, 20.6 to 24.6 dB, and 48.4 to 65 dB, respectively.
Autors: Su, C.-C.;Liu, C.-H.;Lin, C.-M.;Tsai, Y.-L.;Wang, Y.-H.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Feb 2015, volume: 25, issue:2, pages: 124 - 126
Publisher: IEEE
 
» A 25 Gb/s 5.8 mW CMOS Equalizer
Abstract:
Low-power equalization remains in high demand for wireline receivers operating at tens of gigabits per second in copper media. This paper presents a design incorporating a continuous-time linear equalizer and a two-tap half-rate/quarter-rate decision-feedback equalizer that exploits charge steering techniques to reduce the power consumption. Realized in 45 nm technology, the prototype draws 5.8 mW from a 1 V supply and compensates for 24 dB of loss with .
Autors: Jung, J.W.;Razavi, B.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2015, volume: 50, issue:2, pages: 515 - 526
Publisher: IEEE
 
» A 25 GHz Fast-Lock Digital LC PLL With Multiphase Output Using a Magnetically-Coupled Loop of Oscillators
Abstract:
A fast-wakeup bang-bang LC digital phase-locked loop (DPLL) suitable for low-power wireline applications is presented. The PLL uses a novel oscillator design to generate eight output phases using magnetic coupling. The fast-wakeup feature improves power efficiency by allowing PLL power-cycling while accommodating latency requirements. Fast lock upon wakeup is achieved by calibrating the phase of the feedback clock with respect to the reference clock using a first-order loop and is further assisted by on-the-fly adjustment of loop parameters. The eight-phase output clock is generated using a loop of four digitally-controlled oscillators (DCOs) that are magnetically coupled through a passive structure. This structure enables magnetic coupling among oscillators with 2x area improvement over the prior art. As a result, in addition to eliminating the noise and parasitic capacitance of active coupling devices, the compact design reduces parasitic wiring capacitance, which is a significant limitation in high-frequency coupled oscillator design. Implemented in a 40 nm CMOS technology, the design achieves a 40-reference-cycle (100 ns) lock time and a 16% tuning range while producing an 8-phase output clock with less than 2° quadrature phase error up to 25 GHz. Measured PLL jitter is 392 fs (integrated from 100 kHz to 100 MHz) at 25 GHz while drawing 64 mW of power, 23 mW of which is consumed in the multiphase DCO. The DPLL occupies a total area of 0.1 mm 2 .
Autors: Hekmat, M.;Aryanfar, F.;Wei, J.;Gadde, V.;Navid, R.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2015, volume: 50, issue:2, pages: 490 - 502
Publisher: IEEE
 
» A 275 GHz Active Vector-Sum Phase Shifter
Abstract:
Terahertz vector-sum phase shifters capable of 360 phase control over the frequency range of 240 to 310 GHz are presented. Because the impedance mismatch of the variable-gain amplifiers employed in the phase shifter determines the flatness of the offset phases, a new broadband VGA design with its input and output impedances unaffected by dc bias is introduced. The measured results on the phase shifter fabricated using 0.25 m InP HBT technology show incremental phase shifts of 45 with an average RMS offset phase error of 3.6 and insertion loss of to for eight basis dc bias states.
Autors: Quan, C.;Heo, S.;Urteaga, M.;Kim, M.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Feb 2015, volume: 25, issue:2, pages: 127 - 129
Publisher: IEEE
 
» A 40 nm CMOS 195 mW/55 mW Dual-Path Receiver AFE for Multi-Standard 8.5–11.5 Gb/s Serial Links
Abstract:
This paper presents the design of a power- and area-efficient, high-performance dual-path receiver analog front-end (AFE) for wide multistandard applications of 8.5–11.5 Gb/s, such as 10GBASE-LRM, 10GBASE-KR, 10GBASE-CX1, and 10GBASE-LR/SR. A common programmable gain amplifier (PGA) with programmable peaking is followed by ADC-based and slicer-based paths. The ADC-based path employs a low-power, 6-bit 10 Gs/s, 4X time-interleaved, low BER rectified flash 10 Gs/s ADC that is digitally calibrated to compensate for offset, gain, and phase mismatches between the interleaved channels. The ADC-based receiver with transmitter can compensate for up to a 34 dB insertion loss at 5 GHz Nyquist frequency for a copper backplane channel (10GBASE-KR). The ADC-based receiver can achieve greater than 6 dB margin for three 10GBASE-LRM stressors and dynamic channels. The ADC Figure of Merit (FoM) is a 0.59 pJ/conversion-step for a 5 GHz input at a 10.3125 GHz clock rate. The slicer-based path uses a continuous-time linear equalizer (CTLE) after high linear PGA to provide 10 dB total equalization at 5 GHz Nyquist frequency for 10GBASE-SR application. Its measured input sensitivity of 30 mVppd and high-frequency jitter tolerance of 0.35 UIpp with 0.7 UIpp total input jitter well exceed specifications in the standard. The receiver AFE occupies 0.82 mm 2 and consumes 195 mW for ADC path and 55 mW for slicer path in a 40 nm standard CMOS process.
Autors: Zhang, B.;Nazemi, A.;Garg, A.;Kocaman, N.;Ahmadi, M.R.;Khanpour, M.;Zhang, H.;Cao, J.;Momtaz, A.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2015, volume: 50, issue:2, pages: 426 - 439
Publisher: IEEE
 
» A 6 Gb/s Transceiver With a Nonlinear Electronic Dispersion Compensator for Directly Modulated Distributed-Feedback Lasers
Abstract:
This paper presents the design of a 6 Gb/s transceiver with a nonlinear electronic dispersion compensator (EDC) for a directly modulated distributed-feedback (DM-DFB) laser. At the laser output, a DM-DFB laser induces power-dependent frequency chirp, which causes severe chromatic dispersion as well as pattern dependency on the received signal. Such time-varying nature of the dispersion increases the difficulty of compensation using conventional linear methods. The proposed EDC overcomes the chirp-induced dispersion via a nonlinear equalizer at the receiver and a pattern-dependent pre-compensator at the transmitter. The EDC achieves an optical SNR gain of 14.69 dB at a BER of 1 in a 75 km SMF-28 fiber. The test chip is fabricated in a 90 nm CMOS process, and the EDC consumes 68 mW from a 1 V supply at 6 Gb/s.
Autors: Kwon, K.;Yoon, J.;Bae, H.-M.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2015, volume: 50, issue:2, pages: 503 - 514
Publisher: IEEE
 
» A 60 GHz 19.6 dBm Power Amplifier With 18.3% PAE in 40 nm CMOS
Abstract:
This letter reports a fully integrated 60 GHz power amplifier (PA) implemented in TSMC 40 nm CMOS technology. This PA is based on a three-stage two-way differential topology with an output transformer-based power combining network. This topology improves layout symmetry and mitigates parasitic effects between different signal paths to increase overall efficiency. The use of parasitic coupling capacitors inside a vertically-coupled transformer can increase impedance transformation ratio. This PA achieves 20.3 dB power gain, 19.6 dBm output power with 18.3% peak PAE, and 12 GHz bandwidth.
Autors: Tseng, C.-W.;Wang, Y.-J.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Feb 2015, volume: 25, issue:2, pages: 121 - 123
Publisher: IEEE
 
» A 7.92 Gb/s 437.2 mW Stochastic LDPC Decoder Chip for IEEE 802.15.3c Applications
Abstract:
This paper presents the first silicon-proven stochastic LDPC decoder to support multiple code rates for IEEE 802.15.3c applications. The critical path is improved by a reconfigurable stochastic check node unit (CNU) and variable node unit (VNU); therefore, a high throughput scheme can be realized with 768 MHz clock frequency. To achieve higher hardware and energy efficiency, the reduced complexity architecture of tracking forecast memory is experimentally investigated to implement the variable node units for IEEE 802.15.3c applications. Based on the properties of parity check matrices and stochastic arithmetic, the optimized routing networks with re-permutation techniques are adopted to enhance chip utilization. Considering the measurement uncertainties, a delay-lock loop with isolated power domain and a test environment consisting of an encoder, an AWGN generator and bypass circuits are also designed for inner clock and information generation. With these features, our proposed fully parallel LDPC decoder chip fabricated in 90-nm CMOS process with 760.3 K gate count can achieve 7.92 Gb/s data rate and power consumption of 437.2 mW under 1.2 V supply voltage. Compared to the state-of-the-art IEEE 802.15.3c LDPC decoder chips, our proposed chip achieves over 90% reduction of routing wires, 73.8% and 11.5% enhancement of hardware and energy efficiency, respectively.
Autors: Lee, X.-R.;Chen, C.-L.;Chang, H.-C.;Lee, C.-Y.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Feb 2015, volume: 62, issue:2, pages: 507 - 516
Publisher: IEEE
 
» A Temperature-Compensated LC Oscillator Using Constant-Biased Varactors
Abstract:
This letter presents a temperature compensated oscillator for clock generation across a wide temperature range. The proposed technique deploys the characteristics of the constant-biased varactors to nullify the overall oscillator's temperature coefficient (TC), thereby reducing the temperature drift effect on the oscillator frequency output. Fabricated on a CMOS technology, the proposed 2.09 GHz–gm-LC oscillator sees a mere frequency drift from to . The oscillator consumes 10.9 mW at 1.4 V supply, with phase noise of at a 1 MHz offset. The demonstrated technique is useful for providing accurate clock for a variety of applications, including those operating in harsh environment.
Autors: Wang, Y.;Chai, K.T.C.;Mu, X.;Je, M.;Goh, W.L.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Feb 2015, volume: 25, issue:2, pages: 130 - 132
Publisher: IEEE
 
» A Bank of Maximum A Posteriori (MAP) Estimators for Target Tracking
Abstract:
Nonlinear estimation problems, such as range-only and bearing-only target tracking, are often addressed using linearized estimators, e.g., the extended Kalman filter (EKF). These estimators generally suffer from linearization errors as well as the inability to track multimodal probability density functions. In this paper, we propose a bank of batch maximum a posteriori (MAP) estimators as a general estimation framework that provides relinearization of the entire state trajectory, multihypothesis tracking, and an efficient hypothesis generation scheme. Each estimator in the bank is initialized using a locally optimal state estimate for the current time step. Every time a new measurement becomes available, we relax the original batch-MAP problem and solve it incrementally. More specifically, we convert the relaxed one-step-ahead cost function into polynomial or rational form and compute all the local minima analytically. These local minima generate highly probable hypotheses for the target's trajectory and hence greatly improve the quality of the overall MAP estimate. Additionally, pruning of least probable hypotheses and marginalization of old states are employed to control the computational cost. Monte Carlo simulation and real-world experimental results show that the proposed approach significantly outperforms the standard EKF, the batch-MAP estimator, and the particle filter.
Autors: Huang, G.;Zhou, K.;Trawny, N.;Roumeliotis, S.I.;
Appeared in: IEEE Transactions on Robotics
Publication date: Feb 2015, volume: 31, issue:1, pages: 85 - 103
Publisher: IEEE
 
» A Bayesian Nonparametric Approach to Image Super-Resolution
Abstract:
Super-resolution methods form high-resolution images from low-resolution images. In this paper, we develop a new Bayesian nonparametric model for super-resolution. Our method uses a beta-Bernoulli process to learn a set of recurring visual patterns, called dictionary elements, from the data. Because it is nonparametric, the number of elements found is also determined from the data. We test the results on both benchmark and natural images, comparing with several other models from the research literature. We perform large-scale human evaluation experiments to assess the visual quality of the results. In a first implementation, we use Gibbs sampling to approximate the posterior. However, this algorithm is not feasible for large-scale data. To circumvent this, we then develop an online variational Bayes (VB) algorithm. This algorithm finds high quality dictionaries in a fraction of the time needed by the Gibbs sampler.
Autors: Polatkan, G.;Zhou, M.;Carin, L.;Blei, D.;Daubechies, I.;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Feb 2015, volume: 37, issue:2, pages: 346 - 358
Publisher: IEEE
 
» A Bidirectional Control Principle of Active Tuned Hybrid Power Filter Based on the Active Reactor Using Active Techniques
Abstract:
In this paper, a novel bidirectional control principle of active tuned hybrid power filter (ATHPF) based on the active reactor using active techniques is proposed. The proposed control principle, in essence, is to continuously adjust the filter inductance of the active reactor by regulating active power filter (APF) output current in terms of its magnitude and direction. Therefore, the ATHPF using the bidirectional control principle can simultaneously supply different impedances at different selective suppressed harmonic frequencies. The bidirectional control principle can perform both the normal active tuning function and the abnormal active detuning function. To be specific, the normal active tuning function refers to the harmonic elimination with filtering performance independent of the deviation of passive filter parameters, while the latter, the abnormal active detuning function, refers to the flexible protection against harmonic over-current without losing two harmonic elimination and reactive power compensation at the occurrence of harmonic over-current. Experimental results verify the effectiveness of the ATHPF with the bidirectional control principle in selective harmonic elimination and flexible protection against harmonic over-current.
Autors: Deng, Y.;Tong, X.;Jia, H.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Feb 2015, volume: 11, issue:1, pages: 141 - 154
Publisher: IEEE
 
» A Bottom-Gate Indium-Gallium-Zinc Oxide Thin-Film Transistor With an Inherent Etch-Stop and Annealing-Induced Source and Drain Regions
Abstract:
The resistivity of an indium-gallium–zinc oxide (IGZO) thin film was found to depend on not only the conditions of its thermal annealing but also the oxygen-permeability of the cover film during the heat treatment. Based on this observation, a technology for constructing a bottom-gate IGZO thin-film transistor with annealing-induced source and drain (S/D) regions is proposed and demonstrated. The S/D and channel regions with this device architecture are capped, respectively, by impermeable and permeable covers. During a subsequent heat treatment in an oxidizing atmosphere, the resistivity of the S/D regions is greatly reduced; while the channel region, being exposed to the oxidizing atmosphere through the permeable cover, retains its highly resistive character. The permeable cover protects the channel region by serving additionally as an inherent back-channel etch-stop during the etching of the impermeable cover. No patterning is needed to realize this etch-stop, implying a lower manufacturing cost.
Autors: Lu, L.;Wong, M.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Feb 2015, volume: 62, issue:2, pages: 574 - 579
Publisher: IEEE
 
» A Brain–Computer Interface-Based Vehicle Destination Selection System Using P300 and SSVEP Signals
Abstract:
In this paper, we propose a novel driver–vehicle interface for individuals with severe neuromuscular disabilities to use intelligent vehicles by using P300 and steady-state visual evoked potential (SSVEP) brain–computer interfaces (BCIs) to select a destination and test its performance in the laboratory and real driving conditions. The proposed interface consists of two components: the selection component based on a P300 BCI and the confirmation component based on an SSVEP BCI. Furthermore, the accuracy and selection time models of the interface are built to help analyze the performance of the entire system. Experimental results from 16 participants collected in the laboratory and real driving scenarios show that the average accuracy of the system in the real driving conditions is about 99% with an average selection time of about 26 s. More importantly, the proposed system improves the accuracy of destination selection compared with a single P300 BCI-based selection system, particularly for those participants with relatively low level of accuracy in using the P300 BCI. This study not only provides individuals with severe motor disabilities with an interface to use intelligent vehicles and thus improve their mobility, but also facilitates the research on driver–vehicle interface, multimodal interaction, and intelligent vehicles. Furthermore, it opens an avenue on how cognitive neuroscience may be applied to intelligent vehicles.
Autors: Fan, X.;Bi, L.;Teng, T.;Ding, H.;Liu, Y.;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Feb 2015, volume: 16, issue:1, pages: 274 - 283
Publisher: IEEE
 
» A Broadband Dual-Polarized Antenna With Y-Shaped Feeding Lines
Abstract:
A broadband dual-polarized base station antenna is proposed for 2G/3G/LTE bands. The proposed antenna has Y-shaped feeding lines to impart a wide impedance bandwidth to it, and a rectangular box-shaped reflector to enhance its stability in radiation patterns over the operating frequencies. A prototype of the proposed antenna is designed, fabricated, and tested. The measured results show achievement of impedance bandwidth of 45% for at both ports, port-to-port isolation 25 dB , a stable radiation pattern with 3-dB beamwidth at H-plane and V-plane, and a stable antenna gain of 8.2 0.6 dBi from 1.7 to 2.7 GHz. A broadband dual-polarized antenna array with five elements for the band is developed for base station application. Measurements show achievement of array gain of 14.8 1.4 dBi, 3-dB beamwidth at H-plane at port 1 and at port 2 with over the operating frequency band. Simulation results have a good agreement with measurement ones.
Autors: Chu, Q.-X.;Wen, D.-L.;Luo, Y.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2015, volume: 63, issue:2, pages: 483 - 490
Publisher: IEEE
 
» A Broadband Absorber With a Resistive Pattern Made of Ink With Graphene Nano-Platelets
Abstract:
A novel type of a broadband flexible electromagnetic absorbing panel made of a resistive pattern printed on a dielectric spacer backed by a conducting surface is investigated in this paper. It is shown that an appropriate choice of the shape and sheet resistance of the pattern allows extending an absorption spectrum up to an octave and beyond, which is very competitive over alternative solutions. The pattern is made of ink with graphene nano-platelets, which allows achieving expected sheet resistance with decent repeatability, what is confirmed with measurements undertaken with the DC point probe and microwave dielectric resonator techniques. An exemplary sample of the proposed absorber is manufactured and characterized, indicating a very good agreement between theoretical study and experiments.
Autors: Olszewska-Placha, M.;Salski, B.;Janczak, D.;Bajurko, P.R.;Gwarek, W.;Jakubowska, M.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2015, volume: 63, issue:2, pages: 565 - 572
Publisher: IEEE
 
» A buffer-aware HTTP live streaming approach for SDN-enabled 5G wireless networks
Abstract:
With increasing interest in the concept of 5G wireless networks and the popularization of mobile devices, users gradually watch videos through mobile devices in streaming mode rather than off-line mode. However, the latency and lags of mobile networks will reduce the quality of service. In HTTP live streaming services, when there are multiple sources for the same content stored in the streaming servers, the suited quality content is able to be selected for playing according to the networking bandwidth conditions between servers and user equipment, and the users can obtain appropriate streaming quality automatically. However, the selection policy is difficult to be approved between 5G wireless communication networks and SDNs. In this study a buffer-aware HTTP live streaming approach is proposed, which evaluates the weights of media segments to decide the transmitting priorities based on the current playing time and adjust the appropriate transmission path through the decision making network controller according to the utilization and stability of the routers and switches in SDN. Finally, the experimental results proved that the approach is able to correct the overall streaming source sequence with the buffer status to effectively upgrade overall streaming service quality, as well as maintain a certain level of streaming quality for SDN-enable 5G wireless networks.
Autors: Chin-Feng Lai;Ren-Hung Hwang;Han-Chieh Chao;Hassan, M.M.;Alamri, A.;
Appeared in: IEEE Network
Publication date: Feb 2015, volume: 29, issue:1, pages: 49 - 55
Publisher: IEEE
 
» A Buried Ridge Stripe Structure InGaAsP-Si Hybrid Laser
Abstract:
A buried ridge stripe (BRS) structure InGaAsP-Si hybrid laser based on selective area metal bonding (SAMB) method is demonstrated. This novel hybrid laser structure combines the SAMB method’s advantage of low bonding requirements and great flexibility and the BRS lasers’ low threshold, high thermal performance, and good optical field and carrier confinement. The 300- m-long hybrid laser has a threshold current of 14 mA and a maximum single-facet output power of 5.4 mW at room temperature, with a slope efficiency of 0.17 W/A. The laser has a characteristic temperature of 50 K, with continuous wave operation at temperature >50 °C.
Autors: Yuan, L.;Tao, L.;Chen, W.;Li, Y.;Lu, D.;Liang, S.;Yu, H.;Ran, G.;Pan, J.;Wang, W.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Feb 2015, volume: 27, issue:4, pages: 352 - 355
Publisher: IEEE
 
» A Calculation Method of Photovoltaic Array's Operating Point for MPPT Evaluation Based on One-Dimensional Newton–Raphson Method
Abstract:
Comparison and evaluation of maximum power point tracking (MPPT) algorithms for photovoltaic (PV) arrays are often carried out by computer simulation because any irradiation and temperature condition can be set up and repeated. This paper proposes a new simple calculation method for computer simulation to evaluate any MPPT algorithm. The proposed method rapidly calculates the operating point of the PV array. The 1-D Newton–Raphson method is repeated, instead of expanding this method, in multidimensional cases. The proposed method is compared with the conventional combination methods. We confirm the adequate accuracy and short calculation time of the proposed method.
Autors: Uoya, M.;Koizumi, H.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Feb 2015, volume: 51, issue:1, pages: 567 - 575
Publisher: IEEE
 
» A Capacitance-to-Frequency Converter With On-Chip Passivated Microelectrodes for Bacteria Detection in Saline Buffers Up to 575 MHz
Abstract:
To enable impedimetric sensing of whole-cell bacteria in a saline buffer with passivated microelectrodes, we designed a very high frequency (up to 575 MHz) complementary meta–oxide–semiconductor (CMOS) oscillator connected to on-chip interdigitated microelectrodes. The output frequency was theoretically and experimentally shown to be inversely proportional to the permittivity of the solution with a maximal error of 2%, up to an electrical conductivity of 1 S/m. As a biosensing proof-of-concept, successful experimental detection of whole-cell Staphylococcus epidermidis was performed in physiological buffers, showing a detection limit of after 20 min of bacterial incubation. The 0.25- CMOS circuit, combining sensing/readout parts, has a 0.05 area, consumes 29 mW at 250 kS/s, and can be connected to microcontrollers, making the system suitable for point-of-care diagnostics.
Autors: Couniot, N.;Bol, D.;Poncelet, O.;Francis, L.A.;Flandre, D.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Feb 2015, volume: 62, issue:2, pages: 159 - 163
Publisher: IEEE
 
» A Cardiovascular Occlusion Method Based on the Use of a Smart Hydrogel
Abstract:
Smart hydrogels for biomedical applications are highly researched materials. However, integrating them into a device for implantation is difficult. This paper investigates an integrated delivery device designed to deliver an electro-responsive hydrogel to a target location inside a blood vessel with the purpose of creating an occlusion. The paper describes the synthesis and characterization of a Pluronic/methacrylic acid sodium salt electro-responsive hydrogel. Application of an electrical bias decelerates the expansion of the hydrogel. An integrated delivery system was manufactured to deliver the hydrogel to the target location in the body. Ex vivo and in vivo experiments in the carotid artery of sheep were used to validate the concept. The hydrogel was able to completely occlude the blood vessel reducing the blood flow from 245 to 0 ml/min after implantation. Ex vivo experiments showed that the hydrogel was able to withstand physiological blood pressures of > 270 mm·Hg without dislodgement. The results showed that the electro-responsive hydrogel used in this paper can be used to create a long-term occlusion in a blood vessel without any apparent side effects. The delivery system developed is a promising device for the delivery of electro-responsive hydrogels.
Autors: Jackson, N.;Verbrugghe, P.;Cuypers, D.;Adesanya, K.;Engel, L.;Glazer, P.;Dubruel, P.;Shacham-Diamand, Y.;Mendes, E.;Herijgers, P.;Stam, F.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Feb 2015, volume: 62, issue:2, pages: 399 - 406
Publisher: IEEE
 
» A Cascode Miller-Compensated Three-Stage Amplifier With Local Impedance Attenuation for Optimized Complex-Pole Control
Abstract:
This work presents a power- and area-efficient three-stage amplifier that is able to drive a large capacitive load. Removing the inner Miller capacitor and employing cascode Miller compensation in the outer compensation loop could extend the complex-pole frequency of a three-stage amplifier, but result in a high Q-factor. A local impedance attenuation block consisting of a series RC network is proposed to control the complex poles. This block attenuates the high-frequency resistance at the second-stage output and achieves an optimized tradeoff between the frequency and the Q-factor of the complex poles. As the low-frequency resistance remains unchanged, a high dc gain is maintained. Implemented in 0.13 m CMOS process, the proposed design occupies an area of 0.0032 mm 2Pub /_font and consumes a quiescent current of 10.5 A. When driving a 560 pF capacitive load, it achieves a unity-gain frequency of 3.49 MHz, an average slew rate of 0.86 V/ s, and an average settling time of 0.9 s.
Autors: Tan, M.;Ki, W.-H.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2015, volume: 50, issue:2, pages: 440 - 449
Publisher: IEEE
 
» A Case-Based Recommendation Approach for Market Basket Data
Abstract:
In recent years, recommender systems have become an important part of various applications, supporting both customers and providers in their decision-making processes. However, these systems still must overcome limitations that reduce their performance, like recommendations' overspecialization, cold start, and difficulties when items with unequal probability distribution appear or recommendations for sets of items are asked. A novel approach, addressing the above issues through a case-based recommendation methodology, is presented here. The scope of the presented approach is to generate meaningful recommendations based on items' co-occurring patterns and to provide more insight into customers' buying habits. In contrast to current recommendation techniques that recommend items based on users' ratings or history, and to most case-based item recommenders that evaluate items' similarities, the implemented recommender uses a hierarchical model for the items and searches for similar sets of items, in order to recommend those that are most likely to satisfy a user.
Autors: Gatzioura, Anna;Sanchez-Marre, Miquel;
Appeared in: IEEE Intelligent Systems
Publication date: Feb 2015, volume: 30, issue:1, pages: 20 - 27
Publisher: IEEE
 
» A Cauchy-Based State-Space Model for Seizure Detection in EEG Monitoring Systems
Abstract:
This article proposes a state-space model with Cauchy observation noise (SSMC) to detect seizure onset in a long-term EEG monitoring system. Facing the challenge of high false detection rates (FDRs) in many existing methods caused by impulsive EOG/EMG artifacts, the SSMC uses a nonlinear state-space model to encode the gradual changes of epileptic seizure signals and reject abrupt changes brought by artifacts. The Cauchy distribution is proposed to model impulsive observation noises because this heavy-tailed distribution is better at capturing abrupt changes in noise than Gaussian, thus reducing false alarms. Experiments are carried out on a dataset collected from an EEG-monitoring brain-machine interface system that contains 10 patients and 367 hours of EEG data. The authors' method achieves a high sensitivity of 100 percent with a low FDR of 0.08 per hour and a median time delay of 8.10 seconds, demonstrating the method's effectiveness.
Autors: Wang, Yueming;Qi, Yu;Zhu, Junming;Zhang, Jianmin;Wang, Yiwen;Zheng, Xiaoxiang;Wu, Zhaohui;
Appeared in: IEEE Intelligent Systems
Publication date: Feb 2015, volume: 30, issue:1, pages: 6 - 12
Publisher: IEEE
 
» A Charge Recycling SAR ADC With a LSB-Down Switching Scheme
Abstract:
This paper presents a new energy efficient successive approximation analog-to-digital converter (ADC) using a charge recycling and LSB-down switching scheme for the capacitive digital-to-analog converter (CDAC). Compared to the conventional binary weighed CDAC, the proposed technique exhibits a 95% reduction in switching energy, a 50% reduction in capacitor area, and with 30% reduction in nonlinearity under the same unit capacitor size and matching condition. The improvement on the switching energy consumption is the best among reported CDAC switching techniques. To validate the technique, a prototype of 10-bit ADC is fabricated in a 0.13 CMOS technology using standard capacitors. With a unit capacitor size of 30 fF, the ADC consumes 15.6 from a 0.5 V digital supply and a 1 V analog supply. The measured signal-to-noise-plus- distortion ratio is 54.6 dB at 1.1 MS/s. The FOM is 31.8 fJ/conv.-step, which is among the best when normalized to the same unit capacitor size.
Autors: Sun, L.;Li, B.;Wong, A.K.Y.;Ng, W.T.;Pun, K.P.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Feb 2015, volume: 62, issue:2, pages: 356 - 365
Publisher: IEEE
 
» A Closed-Loop Reconfigurable Switched-Capacitor DC-DC Converter for Sub-mW Energy Harvesting Applications
Abstract:
Energy harvesting is an emerging technology for powering wireless sensor nodes, enabling battery-free operation of these devices. In an energy harvesting sensor, a power management circuit is required to regulate the variable harvested voltage to provide a constant supply rail for the sensor circuits. The power management circuit needs to be compact, efficient, and robust to the variations of the input voltage and load current. A closed-form power expression and custom control algorithm for regulation of a switched-capacitor DC-DC converter with optimal conversion efficiency are proposed in this paper. The proposed regulation algorithm automatically adjusts both the voltage gain and switching frequency of a switched-capacitor DC-DC converter based on its input voltage and load current, increasing the power efficiency across a wide input voltage range. The design and simulation of a fully integrated circuit based on the proposed power managing approach is presented. This power management circuit has been simulated in a 0.25 standard CMOS process and simulation results confirm that with an input voltage ranging from 0.5 V to 2.5 V, the converter can generate a regulated 1.2 V output rail and deliver a maximum load current of 100 . The power conversion efficiency is higher than 74% across a wide range of the input voltage with a maximum efficiency of 83%.
Autors: Vaisband, I.;Saadat, M.;Murmann, B.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Feb 2015, volume: 62, issue:2, pages: 385 - 394
Publisher: IEEE
 
» A Compact and Autoclavable System for Acute Extracellular Neural Recording and Brain Pressure Monitoring for Humans
Abstract:
One of the most difficult tasks for the surgeon during the removal of low-grade gliomas is to identify as precisely as possible the borders between functional and non-functional brain tissue with the aim of obtaining the maximal possible resection which allows to the patient the longer survival. For this purpose, systems for acute extracellular recordings of single neuron and multi-unit activity are considered promising. Here we describe a system to be used with 16 microelectrodes arrays that consists of an autoclavable headstage, a built-in inserter for precise electrode positioning and a system that measures and controls the pressure exerted by the headstage on the brain with a twofold purpose: to increase recording stability and to avoid disturbance of local perfusion which would cause a degradation of the quality of the recording and, eventually, local ischemia. With respect to devices where only electrodes are autoclavable, our design permits the reduction of noise arising from long cable connections preserving at the same time the flexibility and avoiding long-lasting gas sterilization procedures. Finally, size is much smaller and set up time much shorter compared to commercial systems currently in use in surgery rooms, making it easy to consider our system very useful for intra-operatory mapping operations.
Autors: Angotzi, G.N.;Baranauskas, G.;Vato, A.;Bonfanti, A.;Zambra, G.;Maggiolini, E.;Semprini, M.;Ricci, D.;Ansaldo, A.;Castagnola, E.;Ius, T.;Skrap, M.;Fadiga, L.;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Feb 2015, volume: 9, issue:1, pages: 50 - 59
Publisher: IEEE
 
» A Compact Four-way Dual-band Power Divider Using Lumped Elements
Abstract:
A compact four-way dual-band microstrip power divider is investigated and demonstrated in this letter. The proposed divider reduces the number of transmission line sections by decomposing a single dual-band transformer into a four-way power divider. The theoretical equations for isolation structures and the design procedures of the power divider are presented. For demonstration, a prototype operating at 1 and 2 GHz is fabricated and measured. Good agreements can be observed between the simulated and measured results.
Autors: Zhang, T.;Che, W.;Chen, H.;Feng, W.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Feb 2015, volume: 25, issue:2, pages: 94 - 96
Publisher: IEEE
 
» A Compact L-Band Bandpass Filter with RF MEMS-Enabled Reconfigurable Notches for Interference Rejection in GPS Applications
Abstract:
In light of today's crowded radio spectrum and the high level of receiver sensitivity required to receive very weak signals, mitigating interference (cosite, intentional jamming, or from other sources) has become a very important topic of research. The recent controversy regarding the use of spectrum close to the global positioning system (GPS) bands is the motivation for the IEEE Microwave Theory and Techniques Society 2014 International Microwave Symposium (IMS2014) Tunable Radio-Frequency (RF) Microelectromechanical Systems (MEMS) Filter Student Design Competition, held in Tampa, Florida. Although there are frequency bands reserved for GPS,there is sometimes interference from undesired signals from a variety of sources, such as radio emissions in adjacent bands, intentional/unintentional jamming, and naturally occurring space weather. Ensuring the continuity of GPS service requires the protection of its spectrum from interference. This competition was intended to interest students in the design of innovative RF front-end solutions to address this issue. This article describes the work of the winners of the first-place award.
Autors: Li, J.;Hickle, M.;Psychogiou, D.;Peroulis, D.;
Appeared in: IEEE Microwave Magazine
Publication date: Feb 2015, volume: 16, issue:1, pages: 81 - 88
Publisher: IEEE
 
» A Compact Low Loss Single-Ended to Two-Way Differential Power Divider/Combiner
Abstract:
This letter presents the analysis and design of a novel compact single-ended to two-way differential passive power divider/combiner using coupled lines. A model for the power combiner/divider is proposed and verified using electromagnetic simulations and measurements. The coupled line power combiner (CLPC) is designed at 5 GHz center frequency and fabricated on a standard 4-layer FR-4 printed circuit board. The combiner core has dimensions of 4.1 8.5 . Measurement results show an input matching below from 3 to 6 GHz, and an insertion loss less than 0.5 dB over the same frequency range. The amplitude mismatch between the output ports is less than 0.5 dB, and the phase mismatch is less than five degrees.
Autors: Muralidharan, S.;Wu, K.;Hella, M.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Feb 2015, volume: 25, issue:2, pages: 103 - 105
Publisher: IEEE
 
» A Compact, Supply-Voltage Scalable 45–66 GHz Baseband-Combining CMOS Phased-Array Receiver
Abstract:
This paper presents a four-element phased-array receiver which achieves 38% fractional bandwidth around 55 GHz. Baseband phase-shifting is employed to eliminate wideband phase-shifters, power dividers, and quadrature splitters operating at millimeter-wave frequencies. Antenna weighting and combining are accomplished using a highly digital Cartesian phase-shifter and current summation, respectively. Transformer-coupling techniques are introduced in the LNA to simultaneously achieve wide bandwidth, reduced noise figure, gain boosting and neutralization. Cascode-free and folded topologies are used throughout to enable operation from a scalable supply voltage. To overcome challenges associated with wideband LO distribution, the LO network employs multiconductor transmission lines to distribute four-phase LO signals. The LO distribution network is absorbed into the LO buffers and terminated by distributed LC loads near the I/Q mixers in each phased-array element. The phased-array receiver is fabricated in a 45 nm SOI CMOS process and achieves 26.2 dB (20.2 dB) of element gain over 21 GHz (19 GHz) of 3 dB bandwidth with 5.5 dB/9.8 dB (7.7 dB/12 dB) minimum/maximum NF while dissipating 30 mW/element (14 mW/element) from a 1.1 V (0.6 V) supply voltage. The worst case 1 dB (input) compression is 28 dBm at 1.1 V. A worst case coupling of 26 dB (45 dB) is measured between adjacent (nonadjacent) elements. The IF bandwidth is 1.2 GHz, limited by the wirebond and PCB interface to the chip. The design occupies only 0.225 mm per element including LO buffer/distribution.
Autors: Kundu, S.;Paramesh, J.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2015, volume: 50, issue:2, pages: 527 - 542
Publisher: IEEE
 
» A Comparative Study of Single-Ended vs. Differential Six-Port Modulators for Wireless Communications
Abstract:
If present, nonlinear effects in a six-port modulator cause distortion and degradation of the quality of the modulated output waveform. How nonlinear effects occur and their impact on system performance were derived in a mathematical model. The model shows that non-ideal performance of the passive six-port correlator is the main contributor to nonlinear distortion. Simulations and measurements on two manufactured six-port modulators were used to validate the theory and to give deeper insight on system performance. It is shown that by using a differentially signaled six-port modulator instead of a single-ended six-port modulator, better performance is achieved over a wide bandwidth. For an error vector magnitude of less than 10%, the relative bandwidth was measured to 12% for the single-ended but 30% for the differentially signaled modulator
Autors: Osth, J.;Karlsson, M.;Serban, A.;Gong, S.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Feb 2015, volume: 62, issue:2, pages: 564 - 570
Publisher: IEEE
 
» A comprehensive comparative study of DGA based transformer fault diagnosis using fuzzy logic and ANFIS models
Abstract:
In this work, Dissolved gas Analysis (DGA) has been implemented using softcomputing models namely fuzzy logic and Adaptive Neuro fuzzy inference system (ANFIS). DGA has developed as an effective tool for the identification of transformer incipient faults. A number of standards and procedures have evolved over the years making DGA more reliable and user friendly. A comparative study of the two models has been developed based on their ability to circumvent the limitations of the IEC 599 standard, Rogers ratio method and Doernenburg???s method. The models have been tested using a reported fault database for their diagnostic capability. Results presented in this paper clearly indicate the superiority of the ANFIS model over the fuzzy system. The ANFIS model presents a reliable system with relative high degree accuracy. ANFIS model being very simple to develop can obviate the limitations of conventional methods of transformer fault diagnosis using DGA.
Autors: Khan, S.A.;Equbal, Md.D.;Islam, T.;
Appeared in: IEEE Transactions on Dielectrics and Electrical Insulation
Publication date: Feb 2015, volume: 22, issue:1, pages: 590 - 596
Publisher: IEEE
 
» A Computational Dynamic Trust Model for User Authorization
Abstract:
Development of authorization mechanisms for secure information access by a large community of users in an open environment is an important problem in the ever-growing Internet world. In this paper we propose a computational dynamic trust model for user authorization, rooted in findings from social science. Unlike most existing computational trust models, this model distinguishes trusting belief in integrity from that in competence in different contexts and accounts for subjectivity in the evaluation of a particular trustee by different trusters. Simulation studies were conducted to compare the performance of the proposed integrity belief model with other trust models from the literature for different user behavior patterns. Experiments show that the proposed model achieves higher performance than other models especially in predicting the behavior of unstable users.
Autors: Zhong, Y.;Bhargava, B.;Lu, Y.;Angin, P.;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Feb 2015, volume: 12, issue:1, pages: 1 - 15
Publisher: IEEE
 
» A Computer-Aided Modeling and Measurement System for Environmental Thermal Comfort Sensing
Abstract:
Predicted mean vote (PMV) is a well-known thermal comfort index with four environmental variables (air temperature, relative humidity, air velocity, and average radiation temperature) and two human factors (metabolic rate and clothing thermal resistance). This paper presents a novel computer-aided thermal comfort measurement system with PMV, which combined the advanced sensors with the virtual instrument technology. The system software is developed using the LabVIEW platform. The measured data can be transmitted to the server-computer in a data center and displayed on a web page through the Internet. The impact of the measurement error of each environmental variable on PMV is analyzed via MATLAB. The system tests were conducted under the certain environmental conditions and Monte Carlo method is deployed to analyze the PMV measurement uncertainty. The experimental results show the feasibility and effectiveness of the proposed system, and confirm that the measurement uncertainty of PMV is not a constant, and varies with the environment changes.
Autors: Qingyuan Zhu;Jian Yi;Shiyue Sheng;Chenglu Wen;Huosheng Hu;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Feb 2015, volume: 64, issue:2, pages: 478 - 486
Publisher: IEEE
 
» A Contraction Theory-Based Analysis of the Stability of the Deterministic Extended Kalman Filter
Abstract:
The contraction properties of the extended Kalman filter, viewed as a deterministic observer for nonlinear systems, are analyzed. The approach relies on the study of an auxiliary “virtual” dynamical system. Some conditions under which exponential convergence of the state error can be guaranteed are derived. Moreover, contraction provides a simple formalism to study some robustness properties of the filter, especially with respect to measurement errors, as illustrated by a simplified inertial navigation example. This technical note sheds another light on the theoretical properties of this popular observer.
Autors: Bonnabel, S.;Slotine, J.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Feb 2015, volume: 60, issue:2, pages: 565 - 569
Publisher: IEEE
 
» A Curve Fitting Approach Using ANN for Converting CT Number to Linear Attenuation Coefficient for CT-based PET Attenuation Correction
Abstract:
Energy-mapping, the conversion of linear attenuation coefficients ( ) calculated at the effective computed tomography (CT) energy to those corresponding to 511 keV, is an important step in CT-based attenuation correction (CTAC) for positron emission tomography (PET) quantification. The aim of this study was to implement energy-mapping step by using curve fitting ability of artificial neural network (ANN). Eleven digital phantoms simulated by Geant4 application for tomographic emission (GATE) and 12 physical phantoms composed of various volume concentrations of iodine contrast were used in this study to generate energy-mapping curves by acquiring average CT values and linear attenuation coefficients at 511 keV of these phantoms. The curves were built with ANN toolbox in MATLAB. To evaluate the effectiveness of the proposed method, another two digital phantoms (liver and spine-bone) and three physical phantoms (volume concentrations of 3%, 10% and 20%) were used to compare the energy-mapping curves built by ANN and bilinear transformation, and a semi-quantitative analysis was proceeded by injecting 0.5 mCi FDG into a SD rat for micro-PET scanning. The results showed that the percentage relative difference (PRD) values of digital liver and spine-bone phantom are 5.46% and 1.28% based on ANN, and 19.21% and 1.87% based on bilinear transformation. For 3%, 10% and 20% physical phantoms, the PRD values of ANN curve are 0.91%, 0.70% and 3.70%, and the PRD values of bilinear transformation are 3.80%, 1.44% and 4.30%, respectively. Both digital and physical phantoms indicated that the ANN curve can achieve better performance than bilinear transformation. The semi-quantitative analysis of rat PET images showed that the ANN curve can reduce the inaccuracy caused by attenuation effect from 13.75% to 4.43% in brain tissue, and 23.26% to 9.41% in heart tissue. On the other hand, the inaccura- y remained 6.47% and 11.51% in brain and heart tissue when the bilinear transformation was used. Overall, it can be concluded that the bilinear transformation method resulted in considerable bias and the newly proposed calibration curve built by ANN could achieve better results with acceptable accuracy.
Autors: Lai, C.-L.;Lee, J.-S.;Chen, J.-C.;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Feb 2015, volume: 62, issue:1, pages: 164 - 170
Publisher: IEEE
 
» A Decision-Error-Tolerant 45 nm CMOS 7b 1 GS/s Nonbinary 2b/Cycle SAR ADC
Abstract:
A compact decision-error-tolerant 2b/cycle SAR ADC architecture is presented. Two DACs with different designated functions, SIG-DAC and REF-DAC, are implemented to make the structure compact and to eliminate the sampling skew issue. Use of a nonbinary decision scheme with decision redundancies not only increases the ADC speed with a relaxed DAC settling requirement but also makes the performance robust to reference fluctuations and comparator offset variations. The proposed dynamic register and direct DAC control scheme enhance the conversion speed by minimizing logic delay in the SAR decision loop. The proposed comparator-error detection with digital error correction scheme enhances high-speed ADC performance. A prototype 7b ADC fabricated in a 45 nm CMOS process operates at a sampling rate of 1 GS/s under a 1.25 V supply while achieving a peak SNDR of 41.6 dB and maintaining an ENOB higher than 6 up to 1.3 GHz signal frequency. The FoM under a 1.25 V supply is an 80 fJ/conversion-step with a power consumption of 7.2 mW.
Autors: Hong, H.-K.;Kim, W.;Kang, H.-W.;Park, S.-J.;Choi, M.;Park, H.-J.;Ryu, S.-T.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2015, volume: 50, issue:2, pages: 543 - 555
Publisher: IEEE
 
» A Deep Learning Network Approach to ab initio Protein Secondary Structure Prediction
Abstract:
Ab initio protein secondary structure (SS) predictions are utilized to generate tertiary structure predictions, which are increasingly demanded due to the rapid discovery of proteins. Although recent developments have slightly exceeded previous methods of SS prediction, accuracy has stagnated around 80 percent and many wonder if prediction cannot be advanced beyond this ceiling. Disciplines that have traditionally employed neural networks are experimenting with novel deep learning techniques in attempts to stimulate progress. Since neural networks have historically played an important role in SS prediction, we wanted to determine whether deep learning could contribute to the advancement of this field as well. We developed an SS predictor that makes use of the position-specific scoring matrix generated by PSI-BLAST and deep learning network architectures, which we call DNSS. Graphical processing units and CUDA software optimize the deep network architecture and efficiently train the deep networks. Optimal parameters for the training process were determined, and a workflow comprising three separately trained deep networks was constructed in order to make refined predictions. This deep learning network approach was used to predict SS for a fully independent test dataset of 198 proteins, achieving a Q3 accuracy of 80.7 percent and a Sov accuracy of 74.2 percent.
Autors: Spencer, M.;Eickholt, J.;Cheng, J.;
Appeared in: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Publication date: Feb 2015, volume: 12, issue:1, pages: 103 - 112
Publisher: IEEE
 
» A Dielectric Model of Human Breast Tissue in Terahertz Regime
Abstract:
The double Debye model has been used to understand the dielectric response of different types of biological tissues at terahertz (THz) frequencies but fails in accurately simulating human breast tissue. This leads to limited knowledge about the structure, dynamics, and macroscopic behavior of breast tissue, and hence, constrains the potential of THz imaging in breast cancer detection. The first goal of this paper is to propose a new dielectric model capable of mimicking the spectra of human breast tissue's complex permittivity in THz regime. Namely, a non-Debye relaxation model is combined with a single Debye model to produce a mixture model of human breast tissue. A sampling gradient algorithm of nonsmooth optimization is applied to locate the optimal fitting solution. Samples of healthy breast tissue and breast tumor are used in the simulation to evaluate the effectiveness of the proposed model. Our simulation demonstrates exceptional fitting quality in all cases. The second goal is to confirm the potential of using the parameters of the proposed dielectric model to distinguish breast tumor from healthy breast tissue, especially fibrous tissue. Statistical measures are employed to analyze the discrimination capability of the model parameters while support vector machines are applied to assess the possibility of using the combinations of these parameters for higher classification accuracy. The obtained analysis confirms the classification potential of these features.
Autors: Truong, B.C.Q.;Tuan, H.D.;Fitzgerald, A.J.;Wallace, V.P.;Nguyen, H.T.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Feb 2015, volume: 62, issue:2, pages: 699 - 707
Publisher: IEEE
 
» A Dielectric Resonator Antenna Array Using Dielectric Insular Image Guide
Abstract:
In this communication, a double-sided Taylor-distribution dielectric resonator antenna array using dielectric insular image guide (DIIG) is presented. Analysis of the dielectric insular resonator antenna (DIRA) is performed with the effective dielectric constant (EDC) method, verified using HFSS™ simulations based on the finite element method (FEM). In order to enhance the gain, the DIRA array is made double-sided, i.e., a mirror image of the array is placed on the other side of the DIIG. The Taylor distribution technique is employed here to suppress the sidelobes. Finally, a 10-element linear DIRA array is fabricated and measured, and a high gain of 15.8 dBi at 36 GHz has been achieved.
Autors: Jin, L.;Lee, R.;Robertson, I.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2015, volume: 63, issue:2, pages: 859 - 862
Publisher: IEEE
 
» A Digitally Controlled Soft Valley Change Technique for a Flyback Converter
Abstract:
In a flyback converter using the conventional valley-switching method, the switching frequency under the light load condition is higher than that under the heavy load condition, which increases the switching loss. A valley skip (VS) technique can reduce the switching frequency under the light load condition. Although it helps to reduce the switching loss, it makes the uncomfortable humming sound caused by a sudden change in switching frequency during valley change. To minimize the audible noise, a new digitally controlled soft valley change (SVC) technique is proposed in this paper. It changes the turn-on instant among valleys gradationally during several switching cycles under any transient situation. The SVC also helps to spread switching frequency so that electromagnetic interference can be reduced. The proposed technique is suitable for the applications that operate under the dynamic load condition such as an audio amplifier. The proposed technique is implemented in an integrated circuit and verified by a prototype experimental test board of 60 W/12 V.
Autors: Ju-Pyo Hong;Gun-Woo Moon;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Feb 2015, volume: 62, issue:2, pages: 966 - 971
Publisher: IEEE
 
» A Distributed Framework for Coordinated Heavy-Duty Vehicle Platooning
Abstract:
Heavy-duty vehicles (HDVs) traveling in single file with small intervehicle distances experience reduced aerodynamic drag and, therefore, have improved fuel economy. In this paper, we attempt to maximize the amount of fuel saved by coordinating platoon formation using a distributed network of controllers. These virtual controllers, placed at major intersections in a road network, help coordinate the velocity of approaching vehicles so they arrive at the junction simultaneously and can therefore platoon. This control is initiated only if the cost of forming the platoon is smaller than the savings incurred from platooning. In a large-scale simulation of the German Autobahn network, we observe that savings surpassing 5% when only a few thousand vehicles participate in the system. These results are corroborated by an analysis of real-world HDV data that show significant platooning opportunities currently exist, suggesting that a slightly invasive network of distributed controllers, such as the one proposed in this paper, can yield considerable savings.
Autors: Larson, J.;Liang, K.;Johansson, K.H.;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Feb 2015, volume: 16, issue:1, pages: 419 - 429
Publisher: IEEE
 
» A Dynamic Mechanical Analysis Technique for Porous Media
Abstract:
Dynamic mechanical analysis (DMA) is a common way to measure the mechanical properties of materials as functions of frequency. Traditionally, a viscoelastic mechanical model is applied and current DMA techniques fit an analytical approximation to measured dynamic motion data by neglecting inertial forces and adding empirical correction factors to account for transverse boundary displacements. Here, a finite-element (FE) approach to processing DMA data was developed to estimate poroelastic material properties. Frequency-dependent inertial forces, which are significant in soft media and often neglected in DMA, were included in the FE model. The technique applies a constitutive relation to the DMA measurements and exploits a nonlinear inversion to estimate the material properties in the model that best fit the model response to the DMA data. A viscoelastic version of this approach was developed to validate the approach by comparing complex modulus estimates to the direct DMA results. Both analytical and FE poroelastic models were also developed to explore their behavior in the DMA testing environment. All of the models were applied to tofu as a representative soft poroelastic material that is a common phantom in elastography imaging studies. Five samples of three different stiffnesses were tested from 1–14 Hz with rough platens placed on the top and bottom surfaces of the material specimen under test to restrict transverse displacements and promote fluid–solid interaction. The viscoelastic models were identical in the static case, and nearly the same at frequency with inertial forces accounting for some of the discrepancy. The poroelastic analytical method was not sufficient when the relevant physical boundary constraints were applied, whereas the poroelastic FE approach produced high quality estimates of shear modulus and hydraulic conductivity. These results illustrated appropriate shear modulus contrast between tofu samples and yielded a consistent - ontrast in hydraulic conductivity as well.
Autors: Pattison, A.J.;McGarry, M.;Weaver, J.B.;Paulsen, K.D.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Feb 2015, volume: 62, issue:2, pages: 443 - 449
Publisher: IEEE
 
» A Fast Readout Electronic System for Accurate Spatial Detection in Ion Beam Tracking for the Next Generation of Particle Accelerators
Abstract:
This paper presents the design, implementation, and measurements of a complete electronic frontend intended for high-resolution spatial detection of ion beams at counting rates higher than 106 particles per second (p/s). The readout system is made up of three main multichannel building blocks, namely, a transimpedance preamplifier, a signal-conditioning line receiver, and a charge-to-digital converter, as well as some off-the-shelf components. The preamplifier and the line receiver have been specifically designed and optimized to minimize the overlapping probability of ion beams tracking, at high counting rates, in low-pressure gaseous secondary electron detectors. Experimental results are shown, considering α particles sources and particles beams, featuring an adaptive shaping time frame of 170-230 ns with a peak signal-to-noise ratio of up to 25 dB. These performance metrics are competitive with the state of the art, demonstrating the suitability of the reported data acquisition and instrumentation system for precise and fast particle tracking detection.
Autors: Garzon-Camacho, A.;Fernandez, B.;Alvarez, M.A.G.;Ceballos, J.;de la Rosa, J.M.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Feb 2015, volume: 64, issue:2, pages: 318 - 327
Publisher: IEEE
 
» A Fast Voltage Clamp Circuit for the Accurate Measurement of the Dynamic ON-Resistance of Power Transistors
Abstract:
For determining the dynamic ON-resistance Rdyn,on of a power transistor, the voltage and current waveforms have to be measured during the switching operation. The novel heterostructure wide-bandgap (e.g., AlGaN/GaN) transistors inherently suffer from the current collapse phenomenon, causing the dynamic ON-resistance to be different from the static. Measuring voltage waveforms using an oscilloscope distorts the characteristics of an amplifier inside the oscilloscope when the range of the measurement channel is not set wide enough to measure both ON-state and OFF-state voltage levels, resulting in failure to accurately measure the voltage waveforms. A novel voltage clamp circuit improving the accuracy of the transistor's ON-state voltage measurement is presented. Unlike the traditional clamping circuit, the presented voltage clamp circuit does not introduce delay caused by RC time constants, keeping the voltage waveform clear, even during state transitions of the device under test. The performance of the presented circuit is illustrated by measurements on a 2-MHz inverted buck converter.
Autors: Gelagaev, R.;Jacqmaer, P.;Driesen, J.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Feb 2015, volume: 62, issue:2, pages: 1241 - 1250
Publisher: IEEE
 
» A Fast-Converging MPPT Technique for Photovoltaic System Under Fast-Varying Solar Irradiation and Load Resistance
Abstract:
Under fast-varying solar irradiation and load resistance, a fast-converging maximum power point tracking (MPPT) system is required to ensure the photovoltaic (PV) system response rapidly with minimum power losses. Traditionally, maximum power point (MPP) locus was used to provide such a fast response. However, the algorithm requires extra control loop or intermittent disconnection of the PV module. Hence, this paper proposes a simpler fast-converging MPPT technique, which excludes the extra control loop and intermittent disconnection. In the proposed algorithm, the relationship between the load line and the curve is used with trigonometry rule to obtain the fast response. Results of the simulation and experiment using single-ended primary-inductor converter showed that the response of the proposed algorithm is four times faster than the conventional incremental conductance algorithm during the load and solar irradiation variation. Consequently, the proposed algorithm has higher efficiency.
Autors: Soon, T.K.;Mekhilef, S.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Feb 2015, volume: 11, issue:1, pages: 176 - 186
Publisher: IEEE
 
» A Fault-Location Algorithm for Series-Compensated Double-Circuit Transmission Lines Using the Distributed Parameter Line Model
Abstract:
A new fault-location algorithm for series-compensated double-circuit transmission lines utilizing two-terminal unsynchronized voltage and current measurements is presented in this paper. The mutual coupling between the parallel lines in the zero-sequence network is fully considered. The distributed parameter line model is adopted to fully take into account the shunt capacitance of the line. By formulating voltages and currents at the fault point in terms of the unknown fault location, boundary conditions under different fault types are used to derive the fault location. Two subroutines assuming the fault occurs on the left or right side of the series compensator are developed and the principle to identify the correct fault-location estimate is described. Matlab SimPowerSystems is employed to generate cases under diverse fault conditions for validating the proposed fault-ocation algorithm. Evaluation studies have shown that the proposed algorithm has achieved quite accurate results.
Autors: Kang, N.;Chen, J.;Liao, Y.;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Feb 2015, volume: 30, issue:1, pages: 360 - 367
Publisher: IEEE
 
» A Fault-Tolerant Strategy to Control the Matrix Converter Under an Open-Switch Failure
Abstract:
In this paper, a new post-fault modulation strategy is proposed to operate the direct matrix converter as close as possible to its desired normal operation under an open-switch fault condition. The proposed strategy determines appropriate switching states associated with eight, out of the nine, remaining healthy switches of the converter, to synthesize the reference voltages. The corresponding duty cycles of the determined switching states are calculated by formulating a nonlinear optimization problem that aims at minimization of the error between the desired reference voltages and the voltages generated by the switching states. The solution to the nonlinear optimization problem is obtained based on the Karush-Kuhn-Tucker conditions. The performance of the proposed modulation strategy is evaluated based on time-domain simulation studies in the MATLAB/Simulink software environment and also experimentally verified.
Autors: Dasika, J.D.;Saeedifard, M.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Feb 2015, volume: 62, issue:2, pages: 680 - 691
Publisher: IEEE
 
» A Feasibility Study on the Adoption of Human Body Communication for Medical Service
Abstract:
A feasibility study on the adoption of human body communication (HBC) for medical service is presented. The electrical specifications of HBC for medical service were reviewed. The ratio of the leakage current into the heart to the output current of a capsule-type transmitter and the propagation loss in the channel were simulated using an anatomical body model. The in-body to on-body channel loss for HBC was provided by electromagnetic simulation from the capsule-type transmitter in the stomach to receiving electrodes on the abdominal region. An analog front end with a sensitivity of 37 μVpp was developed, which showed an improvement of 21 dB against the best report. The 14 mm × 26 mm capsule-type transmitter was implemented, and preclinical experiment was conducted using a live pig. The proposed system successfully transferred data from the capsule-type transmitter in a stomach to the electrodes on the butt and the low jaw of the pig at a high rate of 2 Mb/s at a distance of 90 cm without packet error.
Autors: Hyoung, C.;Hwang, J.;Kang, S.;Park, S.;Kim, Y.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Feb 2015, volume: 62, issue:2, pages: 169 - 173
Publisher: IEEE
 
» A First-Order Optimal Zero-Forcing Beamformer Design for Multiuser MIMO Systems via a Regularized Dual Accelerated Gradient Method
Abstract:
A first-order zero-forcing beamformer design is proposed in this letter for MU-MIMO systems under per-antenna power constraints (PAPC). By forming the regularized dual problem, first-order methods can be applied. To achieve the limit convergence rate of first-order methods, an accelerated method is introduced to solve the regularized dual problem. Simulation results are provided to show the effectiveness of the proposed method.
Autors: Li, B.;Dam, H.H.;Cantoni, A.;Teo, K.L.;
Appeared in: IEEE Communications Letters
Publication date: Feb 2015, volume: 19, issue:2, pages: 195 - 198
Publisher: IEEE
 
» A flexible approach [And Now This???]
Abstract:
Electronic circuits that can bend and flex seem to bring out the science fiction writer in many a reporter (and indeed they've been used in numerous sci-fi movies and TV shows as a convenient way to underline the futuristic nature of a setting). Current excitement about the technology is centered on materials such as OLEDs and carbon nanotubes. But as this ad from May 1965 shows, the exciting future of flexible circuits is actually an old story. (Also worth noting is the reference to Princess telephones, which were first introduced in 1959 and sold until 1994. They are now considered a collectible design classic.)
Autors: Cass, S.;
Appeared in: IEEE Spectrum
Publication date: Feb 2015, volume: 52, issue:2, pages: 68 - 68
Publisher: IEEE
 
» A Flexible Multichannel EEG Feature Extractor and Classifier for Seizure Detection
Abstract:
This brief presents a low-power, flexible, and multichannel electroencephalography (EEG) feature extractor and classifier for the purpose of personalized seizure detection. Various features and classifiers were explored with the goal of maximizing detection accuracy while minimizing power, area, and latency. Additionally, algorithmic and hardware optimizations were identified to further improve performance. The classifiers studied include -nearest neighbor, support vector machines, naïve Bayes, and logistic regression (LR) . All feature and classifier pairs were able to obtain F1 scores over 80% and onset sensitivity of 100% when tested on ten patients. A fully flexible hardware system was implemented that offers parameters for the number of EEG channels, the number of features, the classifier type, and various word width resolutions. Five seizure detection processors with different classifiers have been fully placed and routed on a Virtex-5 field-programmable gate array and been compared. It was found that five features per channel with LR proved to be the best solution for the application of personalized seizure detection. LR had the best average F1 score of 91%, the smallest area and power footprint, and the lowest latency. The ASIC implementation of the same combination in 65-nm CMOS shows that the processor occupies 0.008 mm2 and dissipates 19 nJ at 484 Hz.
Autors: Page, A.;Sagedy, C.;Smith, E.;Attaran, N.;Oates, T.;Mohsenin, T.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Feb 2015, volume: 62, issue:2, pages: 109 - 113
Publisher: IEEE
 
» A Flexible System for the Control of External Magnetic Perturbations in the JET Tokamak
Abstract:
External magnetic perturbations are typically utilized in tokamak devices with two operational or experimental purposes: 1) correction of intrinsic 3-D error fields and 2) mitigation or suppression of edge localized modes (ELMs). At Joint European Torus (JET), dedicated coils are used for the generation of these toroidally asymmetric perturbations. While error fields exist even in the absence of plasma, in ELM mitigation experiments, the external fields are meant to slightly ergodize the magnetic topology in the plasma periphery hence reducing the drive for the destabilization of these instabilities. The control of the magnetic field produced by these coils is achieved by controlling the current flowing in them. The real-time system responsible for this control recently underwent a number of functional improvements since its original implementation utilizing the present voltage-controlled voltage sources. This paper describes the overall system, built-in functionality, and control algorithms and presents preliminary experimental results along with performance assessment studies. In particular, the main improvements are: 1) the possibility of automatically reducing the current references in case the plasma amplifies the applied perturbation; 2) a real-time limitation of to reduce the electromotive force in machine protection diagnostic systems; 3) implementation of a model predictive controller as an alternative to the proportional integral derivative; and 4) the possibility of adapting the current references, in real time, using an external system. The result is a flexible control system contributing toward state-of-the-art physics research at JET’s international and dynamic scientific environment.
Autors: Alves, D.;Coelho, R.;Neto, A.C.;Smith, P.;Valcarcel, D.F.;Card, P.;Felton, R.;Lomas, P.J.;McCullen, P.;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Feb 2015, volume: 43, issue:2, pages: 650 - 664
Publisher: IEEE
 
» A Flow-Weighted Scale-Free Topology for Wireless Sensor Networks
Abstract:
In this paper, complex network theory is used to generate robust scale-free topology for wireless sensor networks (WSNs). Nodes in WSNs consume energy in two stages: network generation and network operation. Existing scale-free models for WSNs focus on the energy in the first stage. However, sensors consume most energy in the second stage. This paper proposes a method called flow-aware scale-free (FASF) model to balance the energy consumption of sensors in the second stage. Taking into account the traffic flow in the network, a WSN is modeled as a weighted network and its energy usage is balanced. Both analysis and simulations indicate that FASF enhances connectivity and network lifetime, achieves high robustness against node failures, and at the same time maintains the scale-invariant property.
Autors: Wang, D.;Liu, E.;Zhang, Z.;Wang, R.;Zhao, S.;Huang, X.;Liu, F.;
Appeared in: IEEE Communications Letters
Publication date: Feb 2015, volume: 19, issue:2, pages: 235 - 238
Publisher: IEEE
 
» A Framework for Generating Geospatial Social Computing Environments
Abstract:
Computational social science plays an important role in emergency management from a quantitative perspective. Reconstructing an individual-based social computing environment is crucial for both accurate computational experiments and determining optimal decisions. Here, the authors propose a formalization method to define basic componential models in the artificial society and the inner logic in these models. A detailed generation process is presented, and multisource statistical data, social interactive behavior, and multilayer social networks are integrated together. As an evaluation of the proposed framework, a virtual city of Beijing is reconstructed. Each citizen is endowed with demographic attributes, including age, gender, social role, correlated geographic locations, and multiple social relations. The generated synthetic population is statistically equivalent to the real population. Transmission experiments of influenza are performed in the reconstructed computational environment, and individual daily interacting behavior is tracked and analyzed. The results indicate that the framework can provide an effective methodology to reconstruct the computing environment in high resolution by using low-resolution statistical data, leading to better prediction and management of emergencies.
Autors: Meng, Rongqing;Ge, Yuanzheng;Cao, Zhidong;Qiu, Xiaogang;Huang, Kedi;
Appeared in: IEEE Intelligent Systems
Publication date: Feb 2015, volume: 30, issue:1, pages: 44 - 52
Publisher: IEEE
 
» A Frequency Reconfigurable Microstrip Antenna Based on Substrate
Abstract:
A novel frequency reconfigurable microstrip antenna based on (BST) substrate is presented. Compared to the complicated structures in traditional reconfigurable antennas, our work is featured by a quite concise design. A theoretical model is proposed to calculate the initial antenna parameters. Both the simulation and the experiment indicate that the coupled aperture structure can efficiently overcome impedance mismatch of BST substrate and obtain a frequency tunability of 10% in Ku band by a DC electric field changing from 0 to 10 m. Besides, similar radiation patterns are obtained in the operating band for both the E plane and H plane. Our study shows that the using of BST material on the frequency reconfigurable antenna is promising, and can be easily extended to reconfigurable antenna arrays.
Autors: Wang, Y.;Liu, Y.;Du, H.;Liu, C.;Xue, Q.;Gao, X.;Li, S.;Lu, Y.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2015, volume: 63, issue:2, pages: 770 - 775
Publisher: IEEE
 
» A Fully Integrated IC With 0.85-μW/Channel Consumption for Epileptic iEEG Detection
Abstract:
Feature extraction from a multichannel compressed neural signal is introduced in this brief. Compressive sensing (CS) is an efficient method for reducing the transmission data rate of sparse biological signals and lowering the power consumption of resource-constrained sensor nodes. However, recovering the original signal from compressed measurements is typically achieved by relatively complex and optimization-based algorithms, which is hardly suitable for real-time applications. The previously proposed multichannel CS scheme enables the area-efficient implementation of CS. In this brief, a low-power feature extraction method based on line length is directly applied in the compressed domain. This approach exploits the spatial sparsity of the signals recorded by adjacent electrodes of a sensor array and detects the seizure onset for every sixteen channels of the array. The proposed circuit architecture is implemented in a UMC 0.18-μm CMOS technology. Extensive performance analysis and design optimization enable a low-power and compact implementation. The proposed feature extractor reaches a perfect sensitivity of 100% for 420 h of clinical data containing 23 seizures from four patients, with an average false alarm rate of 0.34 for artifact-free channels, consuming 0.85 μW of power/channel at a compression rate of 16.
Autors: Shoaran, M.;Pollo, C.;Schindler, K.;Schmid, A.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Feb 2015, volume: 62, issue:2, pages: 114 - 118
Publisher: IEEE
 
» A Fully Integrated Multimode Wireless Power Charger IC With Adaptive Supply Control and Built-In Resistance Compensation
Abstract:
We present a fully integrated multimode lithium-ion battery charger integrated circuit (IC) for wireless power charging applications. The proposed charger IC integrates an analog block for battery charging, a digital control block, an analog-to-digital converter, and memory on a single chip. To improve the charging efficiency, the supply voltage of the charger IC is controlled by an adaptive low-dropout (LDO) regulator. A series-voltage feedback path is formed along the LDO regulator and multimode level shifter, which regulates the supply voltage to closely follow the battery voltage. For a smooth transition during multimode charging, we propose a new approach for built-in resistance compensation. The digital control block of the charger IC is designed in accordance with the Qi standard. The battery charger IC is fabricated in a one-poly six-metal 0.18-μm CMOS process. Integrated with the digital control block and memory, the core area of the multimode charger IC is 0.9 × 1.4 mm2. The input voltage ranges from 4.8 to 5 V. The output voltage is 4.2 V in constant-voltage mode. The charging current in constant-current mode is 450 mA. The maximum and average charging efficiencies are 83% and 79%, respectively.
Autors: Phu Ho Van Quang;Thanh Tien Ha;Jong-Wook Lee;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Feb 2015, volume: 62, issue:2, pages: 1251 - 1261
Publisher: IEEE
 
» A Fully Parallel Nonbinary LDPC Decoder With Fine-Grained Dynamic Clock Gating
Abstract:
Nonbinary LDPC (NB-LDPC) codes, defined over Galois field, offer better coding gain and a lower error floor than binary LDPC codes. However, the complex decoding and large memory requirement have prevented any practical chip implementations. We present a 1.22 Gb/s fully parallel decoder of a GF(64) (160, 80) regular-(2, 4) NB-LDPC code in 65 nm CMOS. The reduced number of edges in NB-LDPC code's factor graph permits a low wiring overhead in the fully parallel architecture. The throughput is further improved by a one-step look-ahead check node design that increases the clock frequency to 700 MHz, and the interleaving of variable node and check node operations that shortens one decoding iteration to 47 clock cycles. We allow each processing node to detect its own convergence and apply dynamic clock gating to save power. When all processing nodes have been clock gated, the decoder terminates and continues with the next input to increase the throughput to 1.22 Gb/s. The dynamic clock gating and decoder termination improve the energy efficiency to 3.03 nJ/b, or 259 pJ/b/iteration, at 1.0 V and 700 MHz. Voltage scaling to 675 mV improves the energy efficiency to 89 pJ/b/iteration for a throughput of 698 Mb/s at 400 MHz.
Autors: Park, Y.S.;Tao, Y.;Zhang, Z.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2015, volume: 50, issue:2, pages: 464 - 475
Publisher: IEEE
 
» A Fuzzy Preference Tree-Based Recommender System for Personalized Business-to-Business E-Services
Abstract:
The Web creates excellent opportunities for businesses to provide personalized online services to their customers. Recommender systems aim to automatically generate personalized suggestions of products/services to customers (businesses or individuals). Although recommender systems have been well studied, there are still two challenges in the development of a recommender system, particularly in real-world B2B e-services: 1) items or user profiles often present complicated tree structures in business applications, which cannot be handled by normal item similarity measures and 2) online users’ preferences are often vague and fuzzy, and cannot be dealt with by existing recommendation methods. To handle both these challenges, this study first proposes a method for modeling fuzzy tree-structured user preferences, in which fuzzy set techniques are used to express user preferences. A recommendation approach to recommending tree-structured items is then developed. The key technique in this study is a comprehensive tree matching method, which can match two tree-structured data and identify their corresponding parts by considering all the information on tree structures, node attributes, and weights. Importantly, the proposed fuzzy preference tree-based recommendation approach is tested and validated using an Australian business dataset and the MovieLens dataset. Experimental results show that the proposed fuzzy tree-structured user preference profile reflects user preferences effectively and the recommendation approach demonstrates excellent performance for tree-structured items, especially in e-business applications. This study also applies the proposed recommendation approach to the development of a web-based business partner recommender system.
Autors: Wu, D.;Zhang, G.;Lu, J.;
Appeared in: IEEE Transactions on Fuzzy Systems
Publication date: Feb 2015, volume: 23, issue:1, pages: 29 - 43
Publisher: IEEE
 
» A Gauss-Seidel Iteration Scheme for Reference-Free 3-D Histological Image Reconstruction
Abstract:
Three-dimensional (3-D) reconstruction of histological slice sequences offers great benefits in the investigation of different morphologies. It features very high-resolution which is still unmatched by in vivo 3-D imaging modalities, and tissue staining further enhances visibility and contrast. One important step during reconstruction is the reversal of slice deformations introduced during histological slice preparation, a process also called image unwarping. Most methods use an external reference, or rely on conservative stopping criteria during the unwarping optimization to prevent straightening of naturally curved morphology. Our approach shows that the problem of unwarping is based on the superposition of low-frequency anatomy and high-frequency errors. We present an iterative scheme that transfers the ideas of the Gauss-Seidel method to image stacks to separate the anatomy from the deformation. In particular, the scheme is universally applicable without restriction to a specific unwarping method, and uses no external reference. The deformation artifacts are effectively reduced in the resulting histology volumes, while the natural curvature of the anatomy is preserved. The validity of our method is shown on synthetic data, simulated histology data using a CT data set and real histology data. In the case of the simulated histology where the ground truth was known, the mean Target Registration Error (TRE) between the unwarped and original volume could be reduced to less than 1 pixel on average after six iterations of our proposed method.
Autors: Gaffling, S.;Daum, V.;Steidl, S.;Maier, A.;Kostler, H.;Hornegger, J.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Feb 2015, volume: 34, issue:2, pages: 514 - 530
Publisher: IEEE
 
» A Generalization of Peres’s Algorithm for Generating Random Bits From Loaded Dice
Abstract:
Peres’s algorithm produces unbiased random bits from biased coin tosses, recursively, using the famous von Neumann’s method as its base. The algorithm is simple and elegant, but, at first glance, appears to work almost like magic and its generalization is elusive. We generalize the method to generate unbiased random bits from loaded dice, i.e., many-valued Bernoulli source. The generalization is asymptotically optimal in its output rate as is the original Peres’s algorithm. Three-valued case is discussed in detail, and then other many-faced cases are considered.
Autors: Pae, S.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Feb 2015, volume: 61, issue:2, pages: 751 - 757
Publisher: IEEE
 
» A Generalized Algorithm and Reconfigurable Architecture for Efficient and Scalable Orthogonal Approximation of DCT
Abstract:
Approximation of discrete cosine transform (DCT) is useful for reducing its computational complexity without significant impact on its coding performance. Most of the existing algorithms for approximation of the DCT target only the DCT of small transform lengths, and some of them are non-orthogonal. This paper presents a generalized recursive algorithm to obtain orthogonal approximation of DCT where an approximate DCT of length could be derived from a pair of DCTs of length at the cost of additions for input preprocessing. We perform recursive sparse matrix decomposition and make use of the symmetries of DCT basis vectors for deriving the proposed approximation algorithm. Proposed algorithm is highly scalable for hardware as well as software implementation of DCT of higher lengths, and it can make use of the existing approximation of 8-point DCT to obtain approximate DCT of any power of two length, . We demonstrate that the proposed approximation of DCT provides comparable or better image and video compression performance than the existing approximation methods. It is shown that proposed algorithm involves lower arithmetic complexity compared with the other existing approximation algorithms. We have presented a fully scalable reconfigurable parallel architecture for the computation of approximate DCT based on the proposed algorithm. One uniquely interesting feature of the proposed design is that it could be configured for the computation of a 32-point DCT or for parallel computation of two 16-point DCTs or four 8-point DCTs with a marginal control overhead. The proposed architecture is found to offer many advantages in terms of hardware complexity, regularity and modularity. Experime- tal results obtained from FPGA implementation show the advantage of the proposed method.
Autors: Jridi, M.;Alfalou, A.;Meher, P.K.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Feb 2015, volume: 62, issue:2, pages: 449 - 457
Publisher: IEEE
 
» A Generalized Voltage Droop Strategy for Control of Multiterminal DC Grids
Abstract:
This paper proposes a generalized voltage droop (GVD) control strategy for dc voltage control and power sharing in voltage source converter (VSC)-based multiterminal dc (MTDC) grids. The proposed GVD control is implemented at the primary level of a two-layer hierarchical control structure of the MTDC grid, and constitutes an alternative to the conventional voltage droop characteristics of voltage-regulating VSC stations, providing higher flexibility and, thus, controllability to these networks. As a difference with other methods, the proposed GVD control strategy can be operated in three different control modes, including conventional voltage droop control, fixed active power control, and fixed dc voltage control, by adjusting the GVD characteristics of the voltage-regulating converters. Such adjustment is carried out in the secondary layer of the hierarchical control structure. The proposed strategy improves the control and power-sharing capabilities of the conventional voltage droop, and enhances its maneuverability. The simulation results, obtained by employing a CIGRE B4 dc grid test system, demonstrate the efficiency of the proposed approach and its flexibility in active power sharing and power control as well as voltage control. In these analysis, it will be also shown how the transitions between the operating modes of the GVD control does not give rise to active power oscillations in the MTDC grids.
Autors: Rouzbehi, K.;Miranian, A.;Candela, J.I.;Luna, A.;Rodriguez, P.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Feb 2015, volume: 51, issue:1, pages: 607 - 618
Publisher: IEEE
 
» A Genetic-Algorithm-Based Approach to Solve Carpool Service Problems in Cloud Computing
Abstract:
Traffic congestion has been a serious problem in many urban areas around the world. Carpooling is one of the most effective solutions to traffic congestion. It consists of increasing the occupancy rate of cars by reducing the empty seats in these vehicles effectively. In this paper, an advanced carpool system is described in detail and called the intelligent carpool system (ICS), which provides carpoolers the use of the carpool services via a smart handheld device anywhere and at any time. The carpool service agency in the ICS is integrated with the abundant geographical, traffic, and societal information and used to manage requests. For help in coordinating the ride matches via the carpool service agency, we apply the genetic algorithm to propose the genetic-based carpool route and matching algorithm (GCRMA) for this multiobjective optimization problem called the carpool service problem (CSP). The experimental section shows that the proposed GCRMA is compared with two single-point methods: the random-assignment hill climbing algorithm and the greedy-assignment hill climbing algorithm on real-world scenarios. Use of the GCRMA was proved to result in superior results involving the optimization objectives of CSP than other algorithms. Furthermore, our GCRMA operates with significantly a small amount of computational complexity to response the match results in the reasonable time, and the processing time is further reduced by the termination criteria of early stop.
Autors: Huang, S.;Jiau, M.;Lin, C.;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Feb 2015, volume: 16, issue:1, pages: 352 - 364
Publisher: IEEE
 
» A Graph-Theoretic Approach to Scheduling in Cognitive Radio Networks
Abstract:
We focus on throughput-maximizing, max-min fair, and proportionally fair scheduling problems for centralized cognitive radio networks. First, we propose a polynomial-time algorithm for the throughput-maximizing scheduling problem. We then elaborate on certain special cases of this problem and explore their combinatorial properties. Second, we prove that the max-min fair scheduling problem is NP-Hard in the strong sense. We also prove that the problem cannot be approximated within any constant factor better than 2 unless . Additionally, we propose an approximation algorithm for the max-min fair scheduling problem with approximation ratio depending on the ratio of the maximum possible data rate to the minimum possible data rate of a secondary users. We then focus on the combinatorial properties of certain special cases and investigate their relation with various problems such as the multiple-knapsack, matching, terminal assignment, and Santa Claus problems. We then prove that the proportionally fair scheduling problem is NP-Hard in the strong sense and inapproximable within any additive constant less than . Finally, we evaluate the performance of our approximation algorithm for the max-min fair scheduling problem via simulations. This approach sheds light on the complexity and combinatorial properties of these scheduling problems, which have high practical importance in centralized cognitive radio networks.
Autors: Gozopek, D.;Shalom, M.;Alagoz, F.;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Feb 2015, volume: 23, issue:1, pages: 317 - 328
Publisher: IEEE
 
» A Hardware Platform for Evaluating Low-Energy Multiprocessor Embedded Systems Based on COTS Devices
Abstract:
Embedded systems are usually energy constrained. Moreover, in these systems, increased productivity and reduced time to market are essential for product success. To design complex embedded systems while reducing the development time and cost, there is a great tendency to use commercial off-the-shelf (“COTS”) devices. At system level, dynamic voltage and frequency scaling (DVFS) is one of the most effective techniques for energy reduction. Nonetheless, many widely used COTS processors either do not have DVFS or apply DVFS only to processor cores. In this paper, an easy-to-implement COTS-based evaluation platform for low-energy embedded systems is presented. To achieve energy saving, DVFS is provided for the whole microcontroller (including core, phase-locked loop, memory, and I/O). In addition, facilities are provided for experimenting with fault-tolerance techniques. The platform is equipped with energy measurement and debugging equipment. Physical experiments show that applying DVFS on the whole microcontroller provides up to 47% and 12% energy saving compared with the sole use of dynamic power management and applying DVFS only on the core, respectively. Although the platform is designed for ARM-based embedded systems, our approach is general and can be applied to other types of systems.
Autors: Salehi, M.;Ejlali, A.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Feb 2015, volume: 62, issue:2, pages: 1262 - 1269
Publisher: IEEE
 
» A Hierarchical Account-Aided Reputation Management System for MANETs
Abstract:
Encouraging cooperation and deterring selfish behaviors are important for proper operations of mobile ad hoc networks (MANETs). For this purpose, most previous efforts rely on either reputation systems or price systems. However, these systems are neither sufficiently effective in providing cooperation incentives nor sufficiently efficient in resource consumption. Nodes in both systems can be uncooperative while still being considered trustworthy. Also, information exchange between mobile nodes in reputation systems and credit circulation in price systems consumes significant resources. This paper presents a hierarchical Account-aided Reputation Management system (ARM) to efficiently and effectively provide cooperation incentives. ARM builds a hierarchical locality-aware distributed hash table (DHT) infrastructure for efficient and integrated operation of both reputation and price systems. The infrastructure helps to globally collect all node reputation information in the system, which can be used to calculate more accurate reputation and detect abnormal reputation information. Also, ARM integrates reputation and price systems by enabling higher-reputed nodes to pay less for their received services. Theoretical analysis demonstrates the properties of ARM. Simulation results show that ARM outperforms the individual reputation system and price system in terms of effectiveness and efficiency of providing cooperation incentives and deterring selfish behaviors.
Autors: Shen, H.;Li, Z.;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Feb 2015, volume: 23, issue:1, pages: 70 - 84
Publisher: IEEE
 

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