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Electrical and Electronics Engineering publications abstract of: 02-2014 sorted by title, page: 0
» 0.73–1.03-GHz Tunable Bandpass Filter With a Reconfigurable 2/3/4-Pole Response
Abstract:
This paper presents a tunable bandpass filter with a reconfigurable-pole response. 2-, 3-, and 4-pole states can be obtained based on employing series resonators with RF switches. The synthesis for the proposed filter is established, and the bandwidth for each pole state can be selected based on theory. The filter is built on a Duroid substrate with and . The tuning for the center frequency is done using Schottky diodes, and the selection of the filter poles is achieved using RF microelectromechanical systems switches. A tuning of 0.73–1.03 GHz is achieved with a 1-dB fractional bandwidth of 3.9%–5.2%. The rejection levels at 200-MHz offset frequency of 2-, 3-, and 4-pole states are 28, 36, and 45 dB, respectively. This filter topology can find applications in reconfigurable radios with dynamic rejection levels.
Autors: Cho, Y.-H.;Rebeiz, G.M.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Feb 2014, volume: 62, issue:2, pages: 290 - 296
Publisher: IEEE
 
» 13.6 mW 79 GHz CMOS Up-Conversion Mixer With 2.1 dB Gain and 35.9 dB LO-RF Isolation
Abstract:
We report a 79 GHz mixer for direct up-conversion using 90 nm CMOS technology. In the mixer, an enhanced double-balanced Gilbert cell with current injection is used to reduce power consumption, and dual negative resistance compensation (NRC) is used to improve conversion gain (CG). In addition, it also includes two Marchand baluns: the single LO input signal to differential signal is converted by one of the baluns, and the differential RF output signal to single signal is converted by the other. The mixer consumes 13.6 mW, achieving IF-port input reflection coefficient of dB at 0.1 GHz, LO-port input reflection coefficient of dB for frequencies 75–90 GHz. At IF of 0.1 GHz and RF of 78.1 GHz, the mixer achieves CG of 2.1 dB and LO-RF isolation of 35.9 dB, the best CG and isolation results ever reported for a W-band silicon-based mixer with power consumption lower than 15 mW.
Autors: Lin, Y.-S.;Wen, W.-C.;Wang, C.-C.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Feb 2014, volume: 24, issue:2, pages: 126 - 128
Publisher: IEEE
 
» 2.4-GHz High-Efficiency Adaptive Power
Abstract:
A 2.4-GHz high-efficiency adaptive rectifier with extended input power range is presented. The rectifier consists of two differential-type sub-rectifiers and a control circuit. The proposed control circuit can detect the input power level by sensing the converted output voltage of the rectifier and then generating two control signals to switch the rectifier between two operation modes. This device has been fabricated in 0.18- CMOS technology. With two three-stage differential-type rectifiers as the sub-rectifiers, the optimal power conversion efficiency (PCE) region is extended to 11 dB by the proposed technique under a 2- load. Moreover, the proposed rectifier has two peak PCEs, which are 47% and 41% at input powers of 8.9 and 2.1 dBm, respectively.
Autors: Li, C.-J.;Lee, T.-C.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Feb 2014, volume: 22, issue:2, pages: 434 - 438
Publisher: IEEE
 
» 2/4-POLE Split-Phase Capacitor Motor for Small Compressors: A Comprehensive Motor Characterization
Abstract:
Compressor electric motor drives play a key role in the energy consumption of residential refrigerators. Electrical efficiency, robustness to starting and overloads and speed variation range define the performance of compressor electric motor drives. Between the lowest cost fixed-speed split-phase capacitor grid-connected induction motor, with lower efficiency, and the higherefficiency grid-connected cage permanent-magnet (PM) rotor split-phase capacitor motor and the inverter fed variable speed PM synchronous motor of highest initial costs, we introduce in this paper a 2 speed grid-connected motor drive. The proposed topology uses a separate split-phase winding, cage-PM-4-pole rotor synchronous motor (PMSM) for low speed (4 poles) and a single-phase (main) winding for 2-pole operation. The tentative target is 85% efficiency at 50 W output for 4-poles (low speed) PMSM operation with good starting and about 60% efficiency in 2-pole (high speed) induction motor operation at 100 W, with smooth transients from low to high speed under full torque load. Circuit models for steady state and for transients with dedicated Matlab codes have been developed, with key FEM validation, to substantiate full scale experiments, and an optimal design methodology embedding both operation modes was put forward, as main theoretical contributions.
Autors: Haddad Kalluf, F.J.;Tutelea, L.N.;Boldea, I.;Espindola, A.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Feb 2014, volume: 50, issue:1, pages: 356 - 363
Publisher: IEEE
 
» 2014 IEEE CIS Awards [Society Briefs]
Abstract:
Presents the recipients of IEEE CIS Society awards in 2014.
Autors: Principe, J.;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Feb 2014, volume: 9, issue:1, pages: 4 - 9
Publisher: IEEE
 
» 24-MHz Scanner for Optoacoustic Imaging of Skin and Burn
Abstract:
Optoacoustic (photoacoustic) imaging uniquely visualizes optical contrast in high resolution and comes with very attractive characteristics for clinical imaging applications. In this paper, we showcase the performance of a scanner based on a 24 MHz center-frequency 128 element array, developed for applications in dermatology. We perform system characterization to examine the imaging performance achieved. We then showcase its imaging ability on healthy tissue and cancer. Finally, we image burns and human lesions in vivo and gain insights on the benefits and challenges of this approach as it is considered for diagnostic and treatment follow-up applications in dermatology and beyond.
Autors: Vionnet, L.;Gateau, J.;Schwarz, M.;Buehler, A.;Ermolayev, V.;Ntziachristos, V.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Feb 2014, volume: 33, issue:2, pages: 535 - 545
Publisher: IEEE
 
» 3-D Mapping With an RGB-D Camera
Abstract:
In this paper, we present a novel mapping system that robustly generates highly accurate 3-D maps using an RGB-D camera. Our approach requires no further sensors or odometry. With the availability of low-cost and light-weight RGB-D sensors such as the Microsoft Kinect, our approach applies to small domestic robots such as vacuum cleaners, as well as flying robots such as quadrocopters. Furthermore, our system can also be used for free-hand reconstruction of detailed 3-D models. In addition to the system itself, we present a thorough experimental evaluation on a publicly available benchmark dataset. We analyze and discuss the influence of several parameters such as the choice of the feature descriptor, the number of visual features, and validation methods. The results of the experiments demonstrate that our system can robustly deal with challenging scenarios such as fast camera motions and feature-poor environments while being fast enough for online operation. Our system is fully available as open source and has already been widely adopted by the robotics community.
Autors: Endres, F.;Hess, J.;Sturm, J.;Cremers, D.;Burgard, W.;
Appeared in: IEEE Transactions on Robotics
Publication date: Feb 2014, volume: 30, issue:1, pages: 177 - 187
Publisher: IEEE
 
» 3.7 kV Vertical GaN PN Diodes
Abstract:
There is a great interest in wide band-gap semiconductor devices for power electronics application. In this letter, vertical GaN p-n diodes fabricated on bulk GaN substrates are discussed. The device layers are grown by MOCVD on low defect density bulk GaN substrates. The measured devices show breakdown voltages of 3.7 kV with an area differential specific on-resistance of 2.95
Autors: Kizilyalli, I.C.;Edwards, A.P.;Nie, H.;Bour, D.;Prunty, T.;Disney, D.;
Appeared in: IEEE Electron Device Letters
Publication date: Feb 2014, volume: 35, issue:2, pages: 247 - 249
Publisher: IEEE
 
» 50 years in icing performance of outdoor insulators
Abstract:
During the last 50 years a significant technical advance, namely in our understanding and control of switching-surge overvoltages, has had some unintended and adverse consequences when designers took full advantage of the possibility of reduced insulator dimensions. Glaze ice accretion can produce harmful effects, especially on closely spaced or large-diameter station post insulators and bushings. Partial or full bridging of the leakage distance occurs for moderate ice-accretion levels and reduces insulator reliability during melting in saturated conditions. Colocation of HV or EHV substations with roads or expressways on which deicing salt is spread has proved particularly problematic. The DEIS has played an important role as a forum for exploring icing flashover physics and as a sponsor of improved test methods and applications guidance.
Autors: Farzaneh, M.;Chisholm, W.;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Feb 2014, volume: 30, issue:1, pages: 14 - 24
Publisher: IEEE
 
» 50+ Years of impedance measurement and spectroscopy, and implementation of virtual spectroscopy based on finite element analysis
Abstract:
Impedance spectroscopy of dielectrics has a long history, going back to Heaviside. Modern multiphysics finite element analysis packages allow dielectric spectra to be computed from detailed physical models for comparison with measurements.
Autors: Shilei Ma;Boggs, S.;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Feb 2014, volume: 30, issue:1, pages: 25 - 31
Publisher: IEEE
 
» 5G wireless communication systems: prospects and challenges [Guest Editorial]
Abstract:
In the last year or so, significant momentum has started to build around the idea of a fifth generation (5G) for wireless communications technology. New research projects have started internationally, and research centers devoted to 5G technology have begun to open. At the ICC 2013 conference in Budapest, there were a number of keynote talks and special invited sessions addressing some of the key concepts around 5G technology. This Special Issue was created by IEEE Communications Magazine to help readers understand the current perspectives on 5G technology from both industry and academic standpoints.
Autors: Thompson, J.;Ge, X.;Wu, H.-C.;Irmer, R.;Jiang, H.;Fettweis, G.;Alamouti, S.;
Appeared in: IEEE Communications Magazine
Publication date: Feb 2014, volume: 52, issue:2, pages: 62 - 64
Publisher: IEEE
 
» 5G: Personal mobile internet beyond what cellular did to telephony
Abstract:
Cellular technology has dramatically changed our society and the way we communicate. First it impacted voice telephony, and then has been making inroads into data access, applications, and services. However, today potential capabilities of the Internet have not yet been fully exploited by cellular systems. With the advent of 5G we will have the opportunity to leapfrog beyond current Internet capabilities.
Autors: Fettweis, G.;Alamouti, S.;
Appeared in: IEEE Communications Magazine
Publication date: Feb 2014, volume: 52, issue:2, pages: 140 - 145
Publisher: IEEE
 
» 5GNOW: non-orthogonal, asynchronous waveforms for future mobile applications
Abstract:
This article provides some fundamental indications about wireless communications beyond LTE/LTE-A (5G), representing the key findings of the European research project 5GNOW. We start with identifying the drivers for making the transition to 5G networks. Just to name one, the advent of the Internet of Things and its integration with conventional human-initiated transmissions creates a need for a fundamental system redesign. Then we make clear that the strict paradigm of synchronism and orthogonality as applied in LTE prevents efficiency and scalability. We challenge this paradigm and propose new key PHY layer technology components such as a unified frame structure, multicarrier waveform design including a filtering functionality, sparse signal processing mechanisms, a robustness framework, and transmissions with very short latency. These components enable indeed an efficient and scalable air interface supporting the highly varying set of requirements originating from the 5G drivers.
Autors: Wunder, G.;Jung, P.;Kasparick, M.;Wild, T.;Schaich, F.;Chen, Y.;Brink, S.T.;Gaspar, I.;Michailow, N.;Festag, A.;Mendes, L.;Cassiau, N.;Ktenas, D.;Dryjanski, M.;Pietrzyk, S.;Eged, B.;Vago, P.;Wiedmann, F.;
Appeared in: IEEE Communications Magazine
Publication date: Feb 2014, volume: 52, issue:2, pages: 97 - 105
Publisher: IEEE
 
» 600 V Diamond Junction Field-Effect Transistors Operated at 200
Abstract:
Blocking characteristics of diamond junction field-effect transistors were evaluated at room temperature (RT) and 200 . A high source-drain bias (breakdown voltage) of 566 V was recorded at RT, whereas it increased to 608 V at 200 . The positive temperature coefficient of the breakdown voltage indicates the avalanche breakdown of the device. We found that the breakdown occurred at the drain edge of the p-n junction between p-channel and the -gates. All four devices measured in this letter showed a maximum gate-drain bias over 500 V at RT and 600 V at 200 .
Autors: Iwasaki, T.;Yaita, J.;Kato, H.;Makino, T.;Ogura, M.;Takeuchi, D.;Okushi, H.;Yamasaki, S.;Hatano, M.;
Appeared in: IEEE Electron Device Letters
Publication date: Feb 2014, volume: 35, issue:2, pages: 241 - 243
Publisher: IEEE
 
» Transparent Conducting Electrodes for Near-Ultraviolet Light-Emitting Diodes
Abstract:
Herein, a -based indium tin oxide thin film is proposed as a replacement for ITO in near-ultraviolet light-emitting diodes (NUV LEDs), and its electrical and optical properties are optimized. The measured sheet resistance and optical transmittance of the thin film were 49 and 93.8% at 405 nm wavelength after optimization, whereas those of ITO films were 52 and 84.4% at that wavelength, respectively. In addition, we found that at 20 mA the output power of the NUV LEDs with top electrodes was 55% greater than that of those with ITO top electrodes.
Autors: Kim, S.J.;Park, S.Y.;Kim, K.H.;Kim, S.W.;Kim, T.G.;
Appeared in: IEEE Electron Device Letters
Publication date: Feb 2014, volume: 35, issue:2, pages: 232 - 234
Publisher: IEEE
 
» Fuzzy Control With Randomly Occurring Infinite Distributed Delays and Channel Fadings
Abstract:
In this paper, the output-feedback control problem is investigated for a class of discrete-time fuzzy systems with randomly occurring infinite distributed delays and channel fadings. A random variable obeying the Bernoulli distribution is introduced to account for the probabilistic infinite distributed delays. The stochastic Rice fading model is employed to simultaneously describe the phenomena of random time delays and channel fadings via setting different values of the channel coefficients. The aim of this paper is to design an output-feedback fuzzy controller such that the closed-loop Takagi–Sugeno (T–S) fuzzy control system is exponentially mean-square stable, and the disturbance rejection attenuation is constrained to a given level by means of the performance index. Intensive analysis is carried out to obtain sufficient conditions for the existence of desired output-feedback controllers, ensuring both the exponential mean-square stability and the prescribed performance. The cone-complementarity linearization algorithm is utilized to cast the controller design problem into a sequential minimization: one that is solvable by the semi-definite programming method. A simulation result is exploited to illustrate the usefulness and effectiveness of the proposed design technique.
Autors: Zhang, S.;Wang, Z.;Ding, D.;Shu, H.;
Appeared in: IEEE Transactions on Fuzzy Systems
Publication date: Feb 2014, volume: 22, issue:1, pages: 189 - 200
Publisher: IEEE
 
» Fuzzy Control With Randomly Occurring Infinite Distributed Delays and Channel Fadings
Abstract:
In this paper, the output-feedback control problem is investigated for a class of discrete-time fuzzy systems with randomly occurring infinite distributed delays and channel fadings. A random variable obeying the Bernoulli distribution is introduced to account for the probabilistic infinite distributed delays. The stochastic Rice fading model is employed to simultaneously describe the phenomena of random time delays and channel fadings via setting different values of the channel coefficients. The aim of this paper is to design an output-feedback fuzzy controller such that the closed-loop Takagi–Sugeno (T–S) fuzzy control system is exponentially mean-square stable, and the disturbance rejection attenuation is constrained to a given level by means of the performance index. Intensive analysis is carried out to obtain sufficient conditions for the existence of desired output-feedback controllers, ensuring both the exponential mean-square stability and the prescribed performance. The cone-complementarity linearization algorithm is utilized to cast the controller design problem into a sequential minimization: one that is solvable by the semi-definite programming method. A simulation result is exploited to illustrate the usefulness and effectiveness of the proposed design technique.
Autors: Zhang, S.;Wang, Z.;Ding, D.;Shu, H.;
Appeared in: IEEE Transactions on Fuzzy Systems
Publication date: Feb 2014, volume: 22, issue:1, pages: 189 - 200
Publisher: IEEE
 
» Transparent Conducting Electrodes for Near-Ultraviolet Light-Emitting Diodes
Abstract:
Herein, a -based indium tin oxide thin film is proposed as a replacement for ITO in near-ultraviolet light-emitting diodes (NUV LEDs), and its electrical and optical properties are optimized. The measured sheet resistance and optical transmittance of the thin film were 49 and 93.8% at 405 nm wavelength after optimization, whereas those of ITO films were 52 and 84.4% at that wavelength, respectively. In addition, we found that at 20 mA the output power of the NUV LEDs with top electrodes was 55% greater than that of those with ITO top electrodes.
Autors: Kim, S.J.;Park, S.Y.;Kim, K.H.;Kim, S.W.;Kim, T.G.;
Appeared in: IEEE Electron Device Letters
Publication date: Feb 2014, volume: 35, issue:2, pages: 232 - 234
Publisher: IEEE
 
» A $(rm UCON_{ABC})$ Resilient Authorization Evaluation for Cloud Computing
Abstract:
The business-driven access control used in cloud computing is not well suited for tracking fine-grained user service consumption. UCONABC applies continuous authorization reevaluation, which requires usage accounting that enables fine-grained access control for cloud computing. However, it was not designed to work in distributed and dynamic authorization environments like those present in cloud computing. During a continuous (periodical) reevaluation, an authorization exception condition, disparity among usage accounting and authorization attributes may occur. This proposal aims to provide resilience to the UCONABC continuous authorization reevaluation, by dealing with individual exception conditions while maintaining a suitable access control in the cloud environment. The experiments made with a proof-of-concept prototype show a set of measurements for an application scenario (e-commerce) and allows for the identification of exception conditions in the authorization reevaluation.
Autors: Marcon, A.L.;Olivo Santin, A.;Stihler, M.;Bachtold, J.;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Feb 2014, volume: 25, issue:2, pages: 457 - 467
Publisher: IEEE
 
» A 0.791 mm On-Chip Self-Aligned Comparator Controller for Boost DC-DC Converter Using Switching Noise Robust Charge-Pump
Abstract:
Herein we propose a new PWM controller for a DC-DC converter with a Self-aligned Comparator Control (SCC), the purpose of which is to overcome sub-harmonic switching and hysteretic characteristics that are problematic in conventional comparator control schemes. In the proposed scheme, the condition of the output voltage is converted to the form of a phase difference through the SCC block. The main control loop of the converter regulates the inductor current which is built up to an optimum value by using this phase difference. In addition to the SCC, the proposed PWM controller is fully integrated on-chip without off-chip components to decrease the size and cost of the DC-DC converter using a new Switching Noise Robust Charge-pump (SNRC). A boost DC-DC converter with the proposed SCC and SNRC was designed and fabricated in a commercial 0.35 m BCDMOS process with total controller area of 0.791 mm 2 . A maximum efficiency of 90% was achieved at a total output power of 480 mW with a switching frequency of 926 kHz when the input and the output voltages were 3.7 V and 8 V, respectively. Over 85% efficiency was maintained over a wide range of output load current from 40 mA to 300 mA.
Autors: Kong, T.-H.;Hong, S.-W.;Cho, G.-H.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2014, volume: 49, issue:2, pages: 502 - 512
Publisher: IEEE
 
» A 0.791 mm On-Chip Self-Aligned Comparator Controller for Boost DC-DC Converter Using Switching Noise Robust Charge-Pump
Abstract:
Herein we propose a new PWM controller for a DC-DC converter with a Self-aligned Comparator Control (SCC), the purpose of which is to overcome sub-harmonic switching and hysteretic characteristics that are problematic in conventional comparator control schemes. In the proposed scheme, the condition of the output voltage is converted to the form of a phase difference through the SCC block. The main control loop of the converter regulates the inductor current which is built up to an optimum value by using this phase difference. In addition to the SCC, the proposed PWM controller is fully integrated on-chip without off-chip components to decrease the size and cost of the DC-DC converter using a new Switching Noise Robust Charge-pump (SNRC). A boost DC-DC converter with the proposed SCC and SNRC was designed and fabricated in a commercial 0.35 μm BCDMOS process with total controller area of 0.791 mm2 . A maximum efficiency of 90% was achieved at a total output power of 480 mW with a switching frequency of 926 kHz when the input and the output voltages were 3.7 V and 8 V, respectively. Over 85% efficiency was maintained over a wide range of output load current from 40 mA to 300 mA.
Autors: Tae-Hwang Kong;Sung-Wan Hong;Gyu-Hyeong Cho;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2014, volume: 49, issue:2, pages: 502 - 512
Publisher: IEEE
 
» A 0.8 THz SiGe HBT Operating at 4.3 K
Abstract:
We demonstrate record ac performance (0.8 THz) for a silicon-germanium heterojunction bipolar transistor (SiGe HBT) operating at cryogenic temperatures. An extracted peak of 798 GHz (peak of 479 GHz) at 4.3 K was measured for a device with a of 1.67 V. This scaled SiGe HBT also exhibits excellent thermal properties, as required from an electro-thermal reliability perspective. Taken together, these results strongly suggest that at the limits of scaling, robust, and manufacturable SiGe HBTs designed for room temperature operation are likely to achieve THz speeds.
Autors: Chakraborty, P.S.;Cardoso, A.S.;Wier, B.R.;Omprakash, A.P.;Cressler, J.D.;Kaynak, M.;Tillack, B.;
Appeared in: IEEE Electron Device Letters
Publication date: Feb 2014, volume: 35, issue:2, pages: 151 - 153
Publisher: IEEE
 
» A 0.8 THz SiGe HBT Operating at 4.3 K
Abstract:
We demonstrate record ac performance (0.8 THz) for a silicon-germanium heterojunction bipolar transistor (SiGe HBT) operating at cryogenic temperatures. An extracted peak fMAX of 798 GHz (peak fT of 479 GHz) at 4.3 K was measured for a device with a BVCEO of 1.67 V. This scaled SiGe HBT also exhibits excellent thermal properties, as required from an electro-thermal reliability perspective. Taken together, these results strongly suggest that at the limits of scaling, robust, and manufacturable SiGe HBTs designed for room temperature operation are likely to achieve THz speeds.
Autors: Chakraborty, P.S.;Cardoso, A.S.;Wier, B.R.;Omprakash, A.P.;Cressler, J.D.;Kaynak, M.;Tillack, B.;
Appeared in: IEEE Electron Device Letters
Publication date: Feb 2014, volume: 35, issue:2, pages: 151 - 153
Publisher: IEEE
 
» A 12 mW Low Power Continuous-Time Bandpass ΔΣ Modulator With 58 dB SNDR and 24 MHz Bandwidth at 200 MHz IF
Abstract:
A 800 MS/s low power fourth-order continuous-time bandpass ΔΣ modulator (CTBPDSM) with 24 MHz bandwidth at a 200 MHz IF uses a novel power-efficient resonator with a single amplifier as a loopfilter. The single op-amp resonator employs positive feedback to increase the Q-factor. A new fourth-order architecture is introduced for system simplicity and power efficiency. Reducing the number of feedback DACs lowers the power consumption and simplifies the modulator structure. A prototype ADC achieves 58 dB SNDR, 60 dB DR and 65 dB IM3, with a total power consumption of 12 mW. The total die area in 65 nm CMOS is 0.2 mm².
Autors: Chae, H.;Jeong, J.;Manganaro, G.;Flynn, M.P.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2014, volume: 49, issue:2, pages: 405 - 415
Publisher: IEEE
 
» A 14b 60 MS/s Pipelined ADC Adaptively Cancelling Opamp Gain and Nonlinearity
Abstract:
Opamp gain and nonlinearity are adaptively cancelled in a pipelined ADC that features global zero-forcing LMS feedback. Two unique circuit concepts are incorporated into the design. One is a programmable gain element that adjusts the opamp gain and nonlinearity error, and the other is a digitally implemented oversampling quantizer that detects the error polarity with high precision. The total opamp-induced error is removed using an opamp input error monitoring algorithm, which also eliminates the opamp noise and offset. The proposed nonlinearity-cancelled bottom-plate sampling helps to realize accurate inter-stage residue transfer and to alleviate the stringent requirement in the design of high-gain wideband opamps. A 60 MS/s pipelined ADC is prototyped in 0.18 µm CMOS. The chip exhibits a 14b INL with a 91 dB SFDR at 1.6 V using a plain un-cascoded two-stage opamp.
Autors: Miyahara, Y.;Sano, M.;Koyama, K.;Suzuki, T.;Hamashita, K.;Song, B.-S.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2014, volume: 49, issue:2, pages: 416 - 425
Publisher: IEEE
 
» A 16.5–28 GHz 0.18- m BiCMOS Power Amplifier With Flat dBm Output Power
Abstract:
A broadband fully integrated power amplifier (PA) with 3 dB bandwidth from 16.5 to 28 GHz was designed using a 0.18 m SiGe BiCMOS process. The PA consists of a drive amplifier and two parallel main amplifiers. Lumped-element Wilkinson power divider and combiner are especially used to combine the main amplifiers as well as to provide suppression for the harmonics through their inherent low-pass filtering characteristic. The PA exhibits measured gain of more than 34.5 dB and very flat output power of dBm across 16.5–28 GHz, and power added efficiency (PAE) higher than 20% and 17% between 16–24.5 GHz and up to 28 GHz, respectively. Specifically at 24 GHz, it achieves 19.4 dBm output power, 22.3% PAE, and 37.6 dB gain.
Autors: Kim, K.;Nguyen, C.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Feb 2014, volume: 24, issue:2, pages: 108 - 110
Publisher: IEEE
 
» A 25-Gb/s 2.2-W 65-nm CMOS Optical Transceiver Using a Power-Supply-Variation-Tolerant Analog Front End and Data-Format Conversion
Abstract:
A one-chip optical transceiver for board-to-board transmission was developed by integrating an analog frontend (FE) with a data-format-conversion (DFC) block in 65-nm CMOS process technology. It was experimentally demonstrated that this transceiver can convert 10x 6.25-Gb/s electrical signals to 4x 25-Gb/s optical signals with 25% redundancy that improves resilience against possible laser diode (LD) failure. To alleviate degradation of the optical link due to power-supply variations, a power-supply-noise-tolerant 25-Gb/s analog FE (consisting of a TIA with a noise canceller and a fully differential LD driver) is proposed. The noise canceller can keep the power-supply variation below 0.2 mV at frequencies down to 1 MHz, and the fully differential LD driver can keep power-supply current variation below 0.64 mApp/ch, despite a large modulation current of 20 mApp. As for the transmission performance of the transceiver, eye diagrams experimentally confirmed 25-Gb/s and 6.25-Gb/s data-transmission rates. A 25-Gb/s optical-link test on the transceiver demonstrated error-free operation at –6.1-dBm OMA. Moreover, an image-transfer test on the transceiver operating at a data rate of 20 Gb/s through a 100-m multi-mode fiber was demonstrated. Total power consumption of the transceiver (including optics) was 2.2 W at full-channel operation.
Autors: Takemoto, T.;Yamashita, H.;Yuki, F.;Masuda, N.;Toyoda, H.;Chujo, N.;Lee, Y.;Tsuji, S.;Nishimura, S.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2014, volume: 49, issue:2, pages: 471 - 485
Publisher: IEEE
 
» A 2T Dual Port Capacitor-Less DRAM
Abstract:
A novel two-transistor (2T) dual port capacitor-less DRAM concept based on bulk floating body is demonstrated for the first time in this letter. The read operation can be performed without disturbance of refresh or write. A novel read method is proposed to improve device performance especially at high temperature. Experimental results show a refresh cycle time of 1.28 s, an initial memory window of 192.84 , and an initial signal sensing margin of 112.75 with sigma variations at 85 . The 2T cell is very promising for high-speed, low-power, and low-cost embedded DRAM application.
Autors: Li, H.;Lin, Y.;
Appeared in: IEEE Electron Device Letters
Publication date: Feb 2014, volume: 35, issue:2, pages: 187 - 189
Publisher: IEEE
 
» A 3-D Near-Field Modeling Approach for Electromagnetic Interference Prediction
Abstract:
This paper presents, through an illustrative example, a 3-D modeling approach to predict the electromagnetic interference (EMI) between complex electronic devices and interconnections placed in the near-field region. Three different analytic coupling formulations have been investigated along with a 3-D-emission model to evaluate the induced voltages in transmission line (TL) extremities in the case of both matched and mismatched TL configurations. The proposed modeling method is successfully validated by comparison with numerical results using electromagnetic (EM) simulation tools and experimental results using near-field measurement. The obtained EM coupling results are more accurate than other traditional 2-D models.
Autors: Shall, H.;Riah, Z.;Kadi, M.;
Appeared in: IEEE Transactions on Electromagnetic Compatibility
Publication date: Feb 2014, volume: 56, issue:1, pages: 102 - 112
Publisher: IEEE
 
» A 32 b 90 nm Processor Implementing Panoptic DVS Achieving Energy Efficient Operation From Sub-Threshold to High Performance
Abstract:
This paper presents a 32 b, 90 nm data flow processor capable of executing arbitrary DSP algorithms using fine grained Dynamic Voltage Scaling (DVS) at the component level with rapid switching and dithering for near-ideal quadratic dynamic energy scaling from 0.25 V–1.2 V. This is the first full processor with Panoptic (all-inclusive) DVS, single clock cycle switching, dithering, and the ability to switch between high performance DVS operation and a sub-threshold mode of operation. This paper also explores header switching and voltage selection considerations for additional savings. Measurements show up to 80% and 43% energy savings of using PDVS over single ( ) and multi- ( ), respectively. Additionally, PDVS shows area savings of up to 65% over given the same energy consumption.
Autors: Craig, K.;Shakhsheer, Y.;Arrabi, S.;Khanna, S.;Lach, J.;Calhoun, B.H.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2014, volume: 49, issue:2, pages: 545 - 552
Publisher: IEEE
 
» A 57.9-to-68.3 GHz 24.6 mW Frequency Synthesizer With In-Phase Injection-Coupled QVCO in 65 nm CMOS Technology
Abstract:
A fully integrated 60 GHz frequency synthesizer with an in-phase injection-coupled quadrature voltage-controlled oscillator (IPIC-QVCO) is proposed. Through a particular symmetrical coupling network formed by diode-connected transistors, the in-phase coupling is realized in the IPIC-QVCO, which reduces both phase noise and phase error. A compact inductor-less divider chain is designed to reduce power consumption. A self-correcting low spur charge pump is employed to reduce reference spur. A standalone 60 GHz IPIC-QVCO and a fully integrated PLL are implemented in standard 65 nm low power CMOS technology. The measurement results show that the QVCO covers a frequency range from 57.88 to 68.33 GHz while consuming 11.4 mW power from a 1.2 V supply. The phase noise of the QVCO is –92 ~ –95 dBc/Hz at 1 MHz offset. The FOM and FOM T of the QVCO are –178.1 ~ –179.7 and –182.5 ~ –184.1 dBc/Hz respectively. The tuning range of the frequency synthesizer is from 57.9 to 68.3 GHz, and the power consumption is 24.6 mW. The phase noise of the frequency synthesizer is –89.8 ~ –91.5 dBc/Hz at 1 MHz offset across the frequency band.
Autors: Yi, X.;Boon, C.C.;Liu, H.;Lin, J.F.;Lim, W.M.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2014, volume: 49, issue:2, pages: 347 - 359
Publisher: IEEE
 
» A 576-Mbit/s 64-QAM 4 4 MIMO Precoding Processor With Lattice Reduction
Abstract:
This brief presents a lattice reduction (LR) aided precoding processor for 64-QAM 4 4 multiple-input–multiple-output systems. The proposed processor is based on a modified Lenstra–Lenstra–Lovász LR algorithm and the Tomlinson–Harashima precoding (THP) algorithm. This study develops a configurable architecture for high-throughput THP processing or high-performance LR-THP processing. The proposed processor can also change the stage number of the LR algorithm to achieve a tradeoff between performance and throughput. This study designs and implements the precoding processor by using TSMC 90-nm 1P9M CMOS technology. The chip measurement results presented in this study show that the proposed processor achieves 576 Mbit/s in the THP mode or bit error rate in the LR-THP mode with 64-QAM modulation at 28.3 dB. The chip occupies a 0.5- area and consumes 15.4 mW of power at its maximum clock speed of 120 MHz.
Autors: Liao, C.-F.;Lan, F.-C.;Jhang, J.-W.;Huang, Y.-H.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Feb 2014, volume: 61, issue:2, pages: 95 - 99
Publisher: IEEE
 
» A 60-GHz Dense Dielectric Patch Antenna Array
Abstract:
The dense dielectric (DD) patch antenna is investigated at the 60-GHz band. By employing the printed circuit board (PCB) technology, a 4 4 aperture-coupled DD patch antenna array is designed, fabricated and studied. An impedance bandwidth of 23.7% from 51.3 to 65.1 GHz for , a gain up to 16.5 dBi with a 3-dB gain bandwidth of 32.5%, and symmetrical broadside radiation patterns with cross-polarization are achieved.
Autors: Li, Y.;Luk, K.-M.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2014, volume: 62, issue:2, pages: 960 - 963
Publisher: IEEE
 
» A 7.65-mW 5-bit 90-nm 1-Gs/s Folded Interpolated ADC Without Calibration
Abstract:
Power consumption of high-speed low-resolution analog-to-digital converters (ADCs) can be reduced by means of calibration. However, this solution has some drawbacks such as time slot allocation for calibration and die area increase. This paper presents a 5-bit 1-Gs/s ADC without calibration, fabricated in 90-nm CMOS. Low power consumption has been ensured by operating at both architecture and comparator levels. A folded interpolated architecture has been adopted. However, compared to standard solutions that use static preamplifiers, the interpolation technique has been implemented by taking recourse to dynamic comparators, enabling significant power saving. Moreover, despite the high operating frequency, intrinsic matching has been ensured while keeping low power consumption. The ADC uses double-tail dynamic comparators, operating with a fixed bias current and with reduced kickback noise. Large input transistors are used to guarantee the targeted matching, thereby avoiding calibration. The ADC achieves 4.3b-ENOB (effective number of bits) and 260-MHz effective resolution bandwidth while consuming 7.65 mW from a 1.2 V supply. The ADC figure of meritis 0.39 pJ/conv. step, which is the state-of-the-art performance for an uncalibrated ADC at this sampling frequency and resolution.
Autors: D'Amico, S.;Cocciolo, G.;Spagnolo, A.;De Matteis, M.;Baschirotto, A.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Feb 2014, volume: 63, issue:2, pages: 295 - 303
Publisher: IEEE
 
» A 72 dB DR, CT ΔΣ Modulator Using Digitally Estimated, Auxiliary DAC Linearization Achieving 88 fJ/conv-step in a 25 MHz BW
Abstract:
This paper presents a single loop, third order continuous time ΔΣ modulator with an internal 4 bit quantizer sampled at 500 MHz with only an oversampling ratio of 10. Since multi-bit operation commonly suffers from DAC non-linearities, and dynamic element matching is ineffective at low oversampling, an alternative auxiliary DAC linearization is proposed for ΔΣ modulators. The unit element mismatches are digitally estimated based on a cross correlation of a binary test signal with the modulator output and represent the measured DNL of DAC1. The corresponding INL is calculated and stored in an 15×8 lookup-table which is applied to the 8 bit auxiliary DAC to linearize DAC1. Moreover, a design centering approach for amplifier finite gain bandwidth compensation within the loop filter is presented which allows for large bandwidth mismatch with negligible effect on loop filter stability. This results in a robust architecture over temperature, supply, and excess loop delay variations. The presented ΔΣ modulator achieves an SNDR of 67.5 dB, DR of 72 dB, and SFDR of 79 dB over a 25 MHz bandwidth and is implemented in a 1.2 V, 90 nm CMOS process. The modulator occupies an active area of 0.19 mm² and has a power consumption of 8.5 mW. It achieves a figure of merit of 88 fJ/conv-step which is one of the best published for multi-bit ΔΣ modulators.
Autors: Kauffman, J.G.;Witte, P.;Lehmann, M.;Becker, J.;Manoli, Y.;Ortmanns, M.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2014, volume: 49, issue:2, pages: 392 - 404
Publisher: IEEE
 
» A 90-nm CMOS 5-Mbps Crystal-Less RF-Powered Transceiver for Wireless Sensor Network Nodes
Abstract:
This paper presents a 90-nm CMOS batteryless transceiver for RF-powered wireless sensor networks. The circuit is made up of a RF energy harvesting module that is implemented through a multi-stage rectifier, a power management unit, and a PLL-based RF front-end that enables TX carrier synthesis by exploiting the RF input signal as a reference frequency. This avoids the use of a local crystal oscillator, thus implementing a highly integrated low-cost wireless transceiver. An active narrowband transmission scheme is adopted with the aim of overcoming the reader self-jamming that limits the operating range of backscattering-based RF-powered devices. The circuit supports a 915-MHz FSK downlink and a 2.45-GHz OOK uplink, while achieving a data rate up to 5 Mbps. It operates with an RF input power as low as –17.1 dBm.
Autors: Papotto, G.;Carrara, F.;Finocchiaro, A.;Palmisano, G.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2014, volume: 49, issue:2, pages: 335 - 346
Publisher: IEEE
 
» A Mode Monoblock Dielectric Filter
Abstract:
A novel monoblock dielectric filter is presented in this paper. The proposed filter is made from a single piece of ceramic with silver-plated external surfaces and a metallic lid for hosting tuning screws. The dominant mode is supported by a centered dielectric rod with one end short-circuited. Not requiring a metallic housing and dielectric resonator mounting fixture, the filter maximizes the space utilization, achieves an optimal factor for a given volume, and provides a high mechanical and thermal stability. One prototype filter operating at 2.6 GHz with 50-MHz bandwidth is designed, fabricated, and measured. To demonstrate its superiorities in terms of factor and thermal stability, a metal coaxial filter of the same size working at the same frequency and bandwidth is fabricated and measured as well. The measured unloaded factor of the monoblock dielectric filter and the metal coaxial filter are about 3000 and 1800, respectively. Furthermore, the frequency drift due to temperature change for the proposed monoblock dielectric filter is ppm/ C while that of its coaxial counterpart is ppm/ C. More detailed design considerations for such monoblock filters are also given.
Autors: Wang, X.;Wu, K.-L.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Feb 2014, volume: 62, issue:2, pages: 275 - 281
Publisher: IEEE
 
» A Multichannel Digital Silicon Photomultiplier With Column-Parallel Time-to-Digital Converter and Basic Characterization
Abstract:
This paper presents a digital silicon photomultiplier (SiPM) partitioned in columns, whereas each column is connected to a column-parallel time-to-digital converter (TDC), in order to improve the timing resolution of single-photon detection. By reducing the number of pixels per TDC using a sharing scheme with three TDCs per column, the pixel-to-pixel skew is reduced. We report the basic characterization of the SiPM, comprising 416 single-photon avalanche diodes (SPADs); the characterization includes photon detection probability, dark count rate, afterpulsing, and crosstalk. We achieved 264-ps full-width at half maximum timing resolution of single-photon detection using a 48-fold column-parallel TDC with a temporal resolution of 51.8 ps (least significant bit), fully integrated in standard complementary metal–oxide semiconductor technology.
Autors: Mandai, S.;Jain, V.;Charbon, E.;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Feb 2014, volume: 61, issue:1, pages: 44 - 52
Publisher: IEEE
 
» A Mode Monoblock Dielectric Filter
Abstract:
A novel monoblock dielectric filter is presented in this paper. The proposed filter is made from a single piece of ceramic with silver-plated external surfaces and a metallic lid for hosting tuning screws. The dominant mode is supported by a centered dielectric rod with one end short-circuited. Not requiring a metallic housing and dielectric resonator mounting fixture, the filter maximizes the space utilization, achieves an optimal factor for a given volume, and provides a high mechanical and thermal stability. One prototype filter operating at 2.6 GHz with 50-MHz bandwidth is designed, fabricated, and measured. To demonstrate its superiorities in terms of factor and thermal stability, a metal coaxial filter of the same size working at the same frequency and bandwidth is fabricated and measured as well. The measured unloaded factor of the monoblock dielectric filter and the metal coaxial filter are about 3000 and 1800, respectively. Furthermore, the frequency drift due to temperature change for the proposed monoblock dielectric filter is ppm/ C while that of its coaxial counterpart is ppm/ C. More detailed design considerations for such monoblock filters are also given.
Autors: Wang, X.;Wu, K.-L.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Feb 2014, volume: 62, issue:2, pages: 275 - 281
Publisher: IEEE
 
» A Bayesian Approach to Device-Free Localization: Modeling and Experimental Assessment
Abstract:
Device-free positioning allows to localize and track passive targets (i.e., not carrying any electronic device) moving in an area monitored by a dense network of low-power and battery-operated wireless sensors. The technology is promising for a wide number of applications, ranging from ambient intelligence in smart spaces, intrusion detection, emergency and rescue operations in critical areas. In this paper, a new approach is proposed where both the average path-loss and the fluctuations of the received signal strength induced by the moving target are jointly modeled based on the theory of diffraction. A novel stochastic model is derived and used for the evaluation of fundamental performance limits. The model is proved to be tight enough to be adopted for real-time estimation of the target location. The proposed localization system is validated by extensive experimental studies in both indoor and outdoor environments. The model calibration is addressed in practical scenarios to compare the performance of different Bayesian online localization methods. The test-bed system supports efficient and flexible target tracking, without requiring any action from the end-users. In addition, the technology is proven to be readily applicable over the existing IEEE 802.15.4 compliant PHY layer standard, by adapting the low-level MAC firmware.
Autors: Savazzi, S.;Nicoli, M.;Carminati, F.;Riva, M.;
Appeared in: IEEE Journal of Selected Topics in Signal Processing
Publication date: Feb 2014, volume: 8, issue:1, pages: 16 - 29
Publisher: IEEE
 
» A Broadcast Approach for Fading Wiretap Channels
Abstract:
A (layered) broadcast approach is studied for the fading wiretap channel without the channel state information (CSI) at the transmitter. Two broadcast schemes, based on superposition coding and embedded coding, respectively, are developed to encode information into a number of layers and use stochastic encoding to keep the corresponding information secret from an eavesdropper. The layers that can be successfully and securely transmitted are determined by the channel states to the legitimate receiver and the eavesdropper. The advantage of these broadcast approaches is that the transmitter does not need to know the CSI to the legitimate receiver and the eavesdropper, but the scheme still adapts to the channel states of the legitimate receiver and the eavesdropper. Three scenarios of block fading wiretap channels with stringent delay constraints are studied, in which either the legitimate receiver's channel, the eavesdropper's channel, or both channels are fading. For each scenario, the secrecy rate that can be achieved via the broadcast approach developed in this paper is derived, and the optimal power allocation over the layers (or the conditions on the optimal power allocation) is also characterized. A notion of probabilistic secrecy, which characterizes the probability that a certain secrecy rate of decoded messages is achieved during one block, is also introduced and studied for scenarios when the eavesdropper's channel is fading. Numerical examples are provided to demonstrate the impact of the CSI at the transmitter and the channel fluctuations of the eavesdropper on the average secrecy rate. These examples also demonstrate the advantage of the proposed broadcast approach over the compound channel approach.
Autors: Liang, Y.;Lai, L.;Poor, H.V.;Shamai, S.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Feb 2014, volume: 60, issue:2, pages: 842 - 858
Publisher: IEEE
 
» A Building Block for Nuclear Medicine Imaging Systems Data Acquisition
Abstract:
Adapting acquisition electronics to new detector designs has often led to complications and compromises. As we developed depth-of-interaction detector designs based on both discrete crystal arrays (dMiCE) and monolithic crystals (cMiCE) concepts, we found that our previous electronics design was inadequate to the task and launched a design effort we have termed our Phase II electronics. The system is based on a basic card design (the Phase II board) that has a large field programmable gate array (FPGA) with sufficient static RAM to support a variety of pulse processing algorithms our group has developed–including timing estimation, pulse integration with pileup correction, and statistical estimation of the event location in the detector. Here we report on the initial development and testing of the Phase II digital board as a basic building block for data acquisition systems.
Autors: Lewellen, T.K.;DeWitt, D.;Miyaoka, R.S.;Hauck, S.;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Feb 2014, volume: 61, issue:1, pages: 79 - 87
Publisher: IEEE
 
» A Car Pooling Model and Solution Method With Stochastic Vehicle Travel Times
Abstract:
Carpooling is one method that can be easily instituted and can help resolve a variety of problems that continue to plague urban areas, ranging from energy demands and traffic congestion to environmental pollution. However, most carpooling organizations currently use a trial-and-error process, in accordance with the projected vehicle travel times, for carpooling, which is neither effective nor efficient. In other words, stochastic disturbances arising from variations in vehicle travel times in actual operations are neglected. In the worst case scenario, where vehicle travel times fluctuate wildly during operations, the planned schedule could be disturbed enough to lose its optimality. Therefore, we constructed a stochastic carpooling model that considers the influence of stochastic travel times. The model is formulated as an integer multiple commodity network flow problem. Since real problem sizes can be large, it could be difficult to find optimal solutions within a reasonable period of time. Therefore, we develop a solution algorithm to solve the model. To test how well the model and the solution algorithm can be applied to the real world, we also developed a simulation-based evaluation method. To test the model and the solution algorithm, a case study is performed based upon data reported from a past study carried out in northern Taiwan. The results show that the model and solution algorithm are good and could be useful for carpooling practices.
Autors: Yan, S.;Chen, C.-Y.;Chang, S.-C.;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Feb 2014, volume: 15, issue:1, pages: 47 - 61
Publisher: IEEE
 
» A case study on IVR applications' provisioning as cloud computing services
Abstract:
Interactive Voice Response (IVR) applications (e.g. automated attendant, automated survey) have become ubiquitous. However, very few, if any, IVR applications are provisioned today as cloud computing services despite all the potential benefits. Cloud computing is an emerging multi-faceted paradigm, whose main facets are Infrastructure as a Service-IaaS, Platform as a Service-PaaS, and Software as a Service- SaaS. This paper proposes a case study on IVR applications?? provisioning as cloud computing services. It identifies the IVR substrates (e.g. key detector, voice recorder and dialog manager) on which the IVR applications rely and proposes at the IaaS level an IVR substrate virtualization infrastructure. Substrates?? virtualization enables a more efficient resource usage, a key benefit inherent to cloud computing. The article also proposes at the PaaS level an accompanying platform to develop and manage the IVR applications which use the identified virtualized substrates. A few typical IVR applications are also developed and managed to illustrate the SaaS facet of cloud computing. The implementation is described, along with the prototype and the performance measurements.
Autors: Belqasmi, F.;Azar, C.;Glitho, R.;Soualhia, M.;Kara, N.;
Appeared in: IEEE Network
Publication date: Feb 2014, volume: 28, issue:1, pages: 33 - 41
Publisher: IEEE
 
» A Chaotic Theorectical Approach to ECG-Based Identity Recognition [Application Notes]
Abstract:
Sophisticated technologies realized from applying the idea of biometric identification are increasingly applied in the entrance security management system, private document protection, and security access control. Common biometric identification involves voice, attitude, keystroke, signature, iris, face, palm or finger prints, etc. Still, there are novel identification technologies based on the individual's biometric features under development [1-4].
Autors: Chen, C.;Lin, C.;Lin, S.;Chiu, Y.;Chiang, C.;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Feb 2014, volume: 9, issue:1, pages: 53 - 63
Publisher: IEEE
 
» A Cocktail Approach for Travel Package Recommendation
Abstract:
Recent years have witnessed an increased interest in recommender systems. Despite significant progress in this field, there still remain numerous avenues to explore. Indeed, this paper provides a study of exploiting online travel information for personalized travel package recommendation. A critical challenge along this line is to address the unique characteristics of travel data, which distinguish travel packages from traditional items for recommendation. To that end, in this paper, we first analyze the characteristics of the existing travel packages and develop a tourist-area-season topic (TAST) model. This TAST model can represent travel packages and tourists by different topic distributions, where the topic extraction is conditioned on both the tourists and the intrinsic features (i.e., locations, travel seasons) of the landscapes. Then, based on this topic model representation, we propose a cocktail approach to generate the lists for personalized travel package recommendation. Furthermore, we extend the TAST model to the tourist-relation-area-season topic (TRAST) model for capturing the latent relationships among the tourists in each travel group. Finally, we evaluate the TAST model, the TRAST model, and the cocktail recommendation approach on the real-world travel package data. Experimental results show that the TAST model can effectively capture the unique characteristics of the travel data and the cocktail approach is, thus, much more effective than traditional recommendation techniques for travel package recommendation. Also, by considering tourist relationships, the TRAST model can be used as an effective assessment for travel group formation.
Autors: Qi Liu;Enhong Chen;Hui Xiong;Yong Ge;Zhongmou Li;Xiang Wu;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Feb 2014, volume: 26, issue:2, pages: 278 - 293
Publisher: IEEE
 
» A Compact Model for Generic MIS-HEMTs Based on the Unified 2DEG Density Expression
Abstract:
In this paper, the 2-D electron gas density and Fermi level analytical expressions as an explicit function of the terminal biases that covers the strong- and moderate-inversion and subthreshold regions and scalable with physical parameters are developed. It is validated by the comparison with the (exact) numerical solutions for different device parameters, in which the device operating region may encompass one or two lowest sub-bands ( and ) in the triangular well. With the unified model, a surface-potential based drain-current model for the metal–insulator–semiconductor (MIS) high electron-mobility transistor (HEMT) is developed. Nonlinear source/drain access region resistances ( and ) can also be modeled via a subcircuit, including an empirical model for capturing the current-collapse effect. The compact drain-current model is shown to match the experimental data of MIS HEMTs very well in both subthreshold and strong-inversion regions, with smooth and symmetric behaviors and including the (dc) self-heating effect. It also models the corresponding MIS diode using the same set of physical and minimum fitting parameters.
Autors: Zhang, J.;Syamal, B.;Zhou, X.;Arulkumaran, S.;Ng, G.I.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Feb 2014, volume: 61, issue:2, pages: 314 - 323
Publisher: IEEE
 
» A Comparison of Frequency-Dependent Soil Models: Application to the Analysis of Grounding Systems
Abstract:
We present a review and comparison of different models representing the frequency dependence of the soil electrical parameters (conductivity and permittivity). These models are expressed in terms of curve-fit expressions for the soil conductivity and relative permittivity, which are based on experimental data. Six available models/expressions are discussed and compared making reference to two sets of experimental data. It is shown that the soil models by Scott, Smith--Longmire, Messier, and Visacro--Alipio predict overall similar results, which are in reasonable agreement with both sets of experimental data. Differences between the soil models are found to be more significant at high frequencies and for low-resistivity soils. The causality of the considered models is tested using the Kramers--Kronig relationships. It is shown that the models/expressions of Smith--Longmire, Messier, and Portela satisfy the Kramers--Kronig relationships and thus provide causal results. The soil models are applied to the analysis of grounding systems subject to a lightning current. A full-wave computational model is adopted for the analysis. The analysis is performed considering two cases: 1) a simple horizontal grounding electrode, and 2) a realistic grounding system of a wind turbine. Two current waveforms associated with typical first and subsequent return strokes are adopted for the representation of the incident lightning current. In agreement with recent studies, simulations show that the frequency dependence of the soil parameters results in a decrease of the potential of the grounding electrode, with respect to the case where the parameters are assumed to be constant. It is found that the models/expressions by Scott, Smith--Longmire, Messier, and Visacro--Alipio predict similar levels of decrease, which vary from about 2% (${rho}_{rm LF}$ = 20 Ω·m and first stroke) up to 45% (${rho}_{rm LF}- = 10 000 Ω·m and subsequent stroke). On the other hand, the models of Portela and Visacro--Portela predict significantly larger levels of the decrease, especially for very high resistivity soils. Furthermore, in the case of a high resistivity soil (10 000 Ω·m), the Visacro--Alipio expression predicts a longer risetime for the grounding potential rise, compared to the predictions of Scott, Smith--Longmire, and Messier models.
Autors: Cavka, D.;Mora, N.;Rachidi, F.;
Appeared in: IEEE Transactions on Electromagnetic Compatibility
Publication date: Feb 2014, volume: 56, issue:1, pages: 177 - 187
Publisher: IEEE
 
» A Concurrent Dual-Band Uneven Doherty Power Amplifier with Frequency-Dependent Input Power Division
Abstract:
A concurrent dual-band uneven GaN Doherty power amplifier (PA) for two wide-spacing frequencies application is proposed in this paper. To avoid an early load modulation-drop caused by the soft turn-on characteristic of the peaking device, an adaptive power division is realized by a frequency-dependent uneven power divider as well as the input matching nonlinearities of the two cells in Doherty PA. Due to the adaptive power division, the proposed dual-band uneven Doherty PA achieves a power-added efficiency of 45% and 41% at the 6 dB backoff from the saturation at 850 MHz and 2330 MHz, respectively, the gain of the proposed Doherty PA is also enhanced to 19 dB and 13 dB in the dual bands. Furthermore, a more accurate two-dimensional joint digital predistortion model (2D-JDPD) is applied to linearize the PA and compensate for the in-phase and quadrature (I/Q) imbalance simultaneously. With this new model, the adjacent channel power ratio (ACPR) is improved to better than −47.1 dBc and −49.4 dBc in the lower and upper bands at an average output power of 31.75 dBm, and a drain efficiency of 26.7% is obtained at the same time.
Autors: Chen, W.;Zhang, S.;Liu, Y.;Liu, Y.;Ghannouchi, F.M.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Feb 2014, volume: 61, issue:2, pages: 552 - 561
Publisher: IEEE
 
» A Constrained ICA Approach for Real-Time Cardiac Artifact Rejection in Magnetoencephalography
Abstract:
Recently, magnetoencephalography (MEG)-based real-time brain computing interfaces (BCI) have been developed to enable novel and promising methods of neuroscience research and therapy. Artifact rejection prior to source localization largely enhances the localization accuracy. However, many BCI approaches neglect real-time artifact removal due to its time consuming processing. With cardiac artifact rejection for real-time analysis (CARTA), we introduce a novel algorithm capable of real-time cardiac artifact (CA) rejection. The method is based on constrained independent component analysis (ICA), where a priori information of the underlying source signal is used to optimize and accelerate signal decomposition. In CARTA, this is performed by estimating the subject's individual density distribution of the cardiac activity, which leads to a subject-specific signal decomposition algorithm. We show that the new method is capable of effectively reducing CAs within one iteration and a time delay of 1 ms. In contrast, Infomax and Extended Infomax ICA converged not until seven iterations, while FastICA needs at least ten iterations. CARTA was tested and applied to data from three different but most common MEG systems (4-D-Neuroimaging, VSM MedTech Inc., and Elekta Neuromag). Therefore, the new method contributes to reliable signal analysis utilizing BCI approaches.
Autors: Breuer, L.;Dammers, J.;Roberts, T.P.L.;Shah, N.J.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Feb 2014, volume: 61, issue:2, pages: 405 - 414
Publisher: IEEE
 
» A Cooperative Heterogeneous Mobile Wireless Mechatronic System
Abstract:
This paper describes a framework for controlling a heterogeneous wireless robotic network consisting of aerial and ground vehicles. By use of the term heterogeneous, we imply the synergy of multiple robotic platforms characterized by different dynamics and specialized sensing capabilities. Two main scenarios concerning wireless communications are presented: 1) a decentralized connectivity strategy in which a mesh of ground mobile routers swarms in a cluttered environment maintaining communication constraints based on spring-mass virtual physics, potential functions, and routing optimization and 2) an autonomous communications relay in GPS-denied environments via antenna diversity and extremum-seeking SNR optimization. For both scenarios, we validate the proposed methodologies by numerical simulations and experiments. One important feature of our test bed is that it can be used for both indoor and outdoor operations.
Autors: Bezzo, N.;Griffin, B.;Cruz, P.;Donahue, J.;Fierro, R.;Wood, J.;
Appeared in: IEEE/ASME Transactions on Mechatronics
Publication date: Feb 2014, volume: 19, issue:1, pages: 20 - 31
Publisher: IEEE
 
» A Data-Driven Approach for Facial Expression Retargeting in Video
Abstract:
This paper presents a data-driven approach for facial expression retargeting in video, i.e., synthesizing a face video of a target subject that mimics the expressions of a source subject in the input video. Our approach takes advantage of a pre-existing facial expression database of the target subject to achieve realistic synthesis. First, for each frame of the input video, a new facial expression similarity metric is proposed for querying the expression database of the target person to select multiple candidate images that are most similar to the input. The similarity metric is developed using a metric learning approach to reliably handle appearance difference between different subjects. Secondly, we employ an optimization approach to choose the best candidate image for each frame, resulting in a retrieved sequence that is temporally coherent. Finally, a spatio-temporal expression mapping method is employed to further improve the synthesized sequence. Experimental results show that our system is capable of generating high quality facial expression videos that match well with the input sequences, even when the source and target subjects have big identity difference. In addition, extensive evaluations demonstrate the high accuracy of the learned expression similarity metric and the effectiveness of our retrieval strategy.
Autors: Li, K.;Dai, Q.;Wang, R.;Liu, Y.;Xu, F.;Wang, J.;
Appeared in: IEEE Transactions on Multimedia
Publication date: Feb 2014, volume: 16, issue:2, pages: 299 - 310
Publisher: IEEE
 
» A day in the life of digi-key
Abstract:
In the 42 years since its founding, Digi-Key Corp. has grown-and grown-into one of the world's largest electronic-component distributors. Its online catalog features nearly a million parts and products. Last year it sold US $1.6 billion worth of merchandise to more than half a million customers in 170 countries. And the vast majority of Digi-Key's offerings are kept in stock, available for immediate shipping, in a single place: the company's 74 000-square-meter warehouse. . That enormous warehouse sits on the southwestern edge of the tiny town of Thief River Falls, Minn. The nearest city is Grand Forks, N.D., hardly a metropolis. The warehouse operates around the clock, 365 days a year, with the result that any order placed by 8 p.m. local time gets shipped out the same day. . Digi-Key, like its archrival Mouser Electronics, caters to both corporate clients and hobbyists. The company will gladly sell you a Xilinx Virtex-7 fieldprogrammable gate array for $39 452.40, but it will also sell you a single 10-cent through-hole resistor. . When you call Digi-Key's toll-free number, an actual person answers, usually within 5 seconds. From there, you'll be guided expertly, even if you have no idea what you need, even if all you're getting is that 10-cent resistor, even if you speak Chinese, Hindi, or Portuguese. In an age of impersonal e-commerce, of voice mail that never gets returned, of languishing on hold, the experience of being a Digi-Key customer can seem almost surreal.
Autors: Kumaga, J.;
Appeared in: IEEE Spectrum
Publication date: Feb 2014, volume: 51, issue:2, pages: 50 - 56
Publisher: IEEE
 
» A Defected Microstrip Structure (DMS)-Based Phase Shifter and Its Application to Beamforming Antennas
Abstract:
In this paper, a beam-steering antenna array that employs a new type of reconfigurable phase shifter is presented. The phase shifter consists of a number of cascaded reconfigurable defected microstrip structure (DMS) units. Each DMS unit is made by etching a slot in a microstrip line and loading the slot with PIN diodes. The “on” and “off” states of the PIN diodes in the DMS unit provide the phase shifts by changing the current paths. Analyses on the performance of various phase shifters cascading different numbers of DMS units are conducted by both simulations and experiments. Using the proposed phase-shifter units and Wilkinson power dividers, a four-element beam-steering antenna array was designed, fabricated, and tested. Experimental results agree well with the simulated ones. The proposed antenna array employing DMS-based phase shifters offers a low-cost solution to beamforming in wireless communications.
Autors: Ding, C.;Guo, Y.J.;Qin, P.-Y.;Bird, T.S.;Yang, Y.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2014, volume: 62, issue:2, pages: 641 - 651
Publisher: IEEE
 
» A Detailed Study of Gate Insulator Process Dependence of NBTI Using a Compact Model
Abstract:
Process impact of negative bias temperature instability (NBTI) is studied in silicon oxynitride (SiON) and high- metal gate (HKMG) p-MOSFETs. An analytical compact model is used to predict long time degradation. NBTI is shown to be governed by the generation of interface and bulk oxide traps and hole trapping in preexisting traps that are mutually uncorrelated. Experimental evidences are provided to independently verify underlying components. Model parameters are extracted; only a few process-dependent parameters are needed to predict the experimental data from wide range of SiON and HKMG p-MOSFETs at various stress bias and temperature. Similarity between SiON and HKMG devices is highlighted.
Autors: Joshi, K.;Mukhopadhyay, S.;Goel, N.;Nanware, N.;Mahapatra, S.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Feb 2014, volume: 61, issue:2, pages: 408 - 415
Publisher: IEEE
 
» A Digitally Controlled Low-EMI SPWM Generation Method for Inverter Applications
Abstract:
This paper presents a digitally controlled way of generating the sinusoidal signal with less memory consumption. Moreover, this paper also presents a new switching frequency modulation technique. This technique utilizes the concept of spread spectrum frequency modulation that is used to suppress the electromagnetic interference (EMI) caused by high switching frequencies. Measurement results at the output sine pulse-width generation show that when the spread spectrum technique was applied to the conventional triangular wave and the fundamental, second, and third harmonics of switching frequency were reduced, respectively, by 12.8, 11.2, and 16.4 dB trading off with the slight increase in total harmonic distortion (THD) of 0.092% from a THD of 2.34%. While in the inverter output, there was a 14-dB reduction in EMI peak in exchange to 0.12% increase in THD from a THD of 2.57%.
Autors: Wan-Rone Liou;Villaruza, H.M.;Mei-Ling Yeh;Roblin, P.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Feb 2014, volume: 10, issue:1, pages: 73 - 83
Publisher: IEEE
 
» A Distributed Information Divergence Estimation over Data Streams
Abstract:
In this paper, we consider the setting of large scale distributed systems, in which each node needs to quickly process a huge amount of data received in the form of a stream that may have been tampered with by an adversary. In this situation, a fundamental problem is how to detect and quantify the amount of work performed by the adversary. To address this issue, we propose a novel algorithm AnKLe for estimating the Kullback-Leibler divergence of an observed stream compared with the expected one. AnKLe combines sampling techniques and information-theoretic methods. It is very efficient, both in terms of space and time complexities, and requires only a single pass over the data stream. We show that AnKLe is an (ε, δ)-approximation algorithm with a space complexity Õ(1/ε + 1/ε2) bits in "most" cases, and Õ(1/ε + (n-ε-1)/ε2) otherwise, where n is the number of distinct data items in a stream. Moreover, we propose a distributed version of AnKLe that requires at most O (rℓ (log n + 1)) bits of communication between the ℓ participating nodes, where r is number of rounds of the algorithm. Experimental results show that the estimation provided by AnKLe remains accurate even for different adversarial settings for which the quality of other methods dramatically decreases.
Autors: Anceaume, E.;Busnel, Y.;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Feb 2014, volume: 25, issue:2, pages: 478 - 487
Publisher: IEEE
 
» A Distributed Real-Time Java-Centric Architecture for Industrial Systems
Abstract:
There is a trend in industrial systems towards the use of common-off-the-shelf (COTS) components to develop applications that interact with open systems. This trend includes among others the use of high-level languages, such as Java, and Internet protocols (HTTP and Web Services). Although many industrial systems use these technologies at their business layers, they are far from offering a homogeneous programming platform in their most internal infrastructures. This paper extends the current practice by introducing a real-time Java-centric architecture for industrial systems. The architecture integrates existing and upcoming technology to define a Java-based approach. The empirical evidence, included in the paper, illustrates the performance of the core of the industrial layer of this architecture.
Autors: Basanta-Val, P.;Garcia-Valls, M.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Feb 2014, volume: 10, issue:1, pages: 27 - 34
Publisher: IEEE
 
» A Disturbance-Adaptive Design for VANET-Enabled Vehicle Platoon
Abstract:
In highway systems, grouping vehicles into platoons can improve road capacity and energy efficiency. With the advance of technologies, the performance of platoons can be further enhanced by vehicular ad hoc networks (VANETs). In the past few years, many studies have been conducted on the dynamics of a VANET-enabled platoon under traffic disturbance, which is a common scenario on a highway. However, most of them do not consider the impact of platoon dynamics on the behaviors of VANETs. Moreover, most existing studies focus on how to maintain the stability of a platoon and do not address how to mitigate negative effects of traffic disturbance, such as uncomfortable passenger experience, increased fuel consumption, and increased exhaust emission. In this paper, we will investigate the dynamics of the VANET-enabled platoon from an integrated perspective. In particular, we first propose a novel disturbance-adaptive platoon (DA-Platoon) architecture, in which a platoon controller shall adapt to the disturbance scenario and shall consider both VANET and platoon dynamics requirements. Based on a specific realization of the DA-Platoon architecture, we then analyze the traffic dynamics inside a platoon and derive desired parameters, including intraplatoon spacing and platoon size, so as to satisfy VANET constraints under traffic disturbance. To mitigate the adverse effects of traffic disturbance, we also design a novel driving strategy for the leading vehicle of a platoon, with which we can determine the desired interplatoon spacing. Finally, we conduct extensive simulation experiments, which not only validate our analysis but also demonstrate the effectiveness of the proposed driving strategy.
Autors: Jia, D.;Lu, K.;Wang, J.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Feb 2014, volume: 63, issue:2, pages: 527 - 539
Publisher: IEEE
 
» A Doppler Robust Design of Transmit Sequence and Receive Filter in the Presence of Signal-Dependent Interference
Abstract:
In this paper, we study the joint design of Doppler robust transmit sequence and receive filter to improve the performance of an active sensing system dealing with signal-dependent interference. The signal-to-noise-plus-interference (SINR) of the filter output is considered as the performance measure of the system. The design problem is cast as a max-min optimization problem to robustify the system SINR with respect to the unknown Doppler shifts of the targets. To tackle the design problem, which belongs to a class of NP-hard problems, we devise a novel method (which we call DESIDE) to obtain optimized pairs of transmit sequence and receive filter sharing the desired robustness property. The proposed method is based on a cyclic maximization of SINR expressions with relaxed rank-one constraints, and is followed by a novel synthesis stage. We devise synthesis algorithms to obtain high quality pairs of transmit sequence and receive filter that well approximate the behavior of the optimal SINR (of the relaxed problem) with respect to target Doppler shift. Several numerical examples are provided to analyze the performance obtained by DESIDE.
Autors: Naghsh, M.M.;Soltanalian, M.;Stoica, P.;Modarres-Hashemi, M.;De Maio, A.;Aubry, A.;
Appeared in: IEEE Transactions on Signal Processing
Publication date: Feb 2014, volume: 62, issue:4, pages: 772 - 785
Publisher: IEEE
 
» A Double-Pulse Technique for the Dynamic I/V Characterization of GaN FETs
Abstract:
Standard dynamic characterization methods based on periodic narrow-pulse low duty-cycle excitation waveforms provide suboptimal I/V curves when used along with GaN field effect transistors (FETs), due to complex nonlinear charge trapping effects. Thus, a double-pulse technique for the dynamic characterization of GaN FETs is here presented. The double-pulsed I/V characteristics are shown to be not only isothermal but also corresponding to a fixed charge trapping state.
Autors: Santarelli, A.;Cignani, R.;Gibiino, G.P.;Niessen, D.;Traverso, P.A.;Florian, C.;Schreurs, D.M.M.-P.;Filicori, F.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Feb 2014, volume: 24, issue:2, pages: 132 - 134
Publisher: IEEE
 
» A Dual-Frequency Ultralow-Power Efficient 0.5-g Rectenna
Abstract:
The second annual Student Wireless Energy Harvesting (WEH) Design Competition was held during the 2013 IEEE Microwave Theory and Techniques Society (MTT_S) International Microwave Symposium (IMS2013) in Seattle, Washington, United States. This year, the competition parameters were modified from those of last year [1], and a new figure of merit (FoM) was established. The overall goal of the competition was to demonstrate low-mass hardware that can efficiently receive and rectify extremely low-incident power densities at two frequencies, with a fixed dc load. As the radio-frequency (RF) environment gets more saturated with spurious power, designs from this competition will become a feasible way to energize ultralow-powered or low-duty-cycle hard-to-reach sensors. Concepts such as Internet-of-Things, in which small ubiquitous devices and sensors will log data and send it to the cloud, could benefit from wireless energy harvesters. These sensors will not have convenient ways to stay powered unless power harvesting circuits are used for the sensor hardware.
Autors: Scheeler, R.;Korhummel, S.;Popovic, Z.;
Appeared in: IEEE Microwave Magazine
Publication date: Feb 2014, volume: 15, issue:1, pages: 109 - 114
Publisher: IEEE
 
» A Dynamic Observation Capability Index for Quantitatively Pre-Evaluating Diverse Optical Imaging Satellite Sensors
Abstract:
Choosing a capable satellite sensor from a mass of homogeneous sensors to meet the requirements of observation tasks in various application scenarios is one of the basic challenges faced by the collaborative observation in an Earth Observation Sensor Web environment. This paper analyzed five main factors affecting the observation capability of optical imaging satellite sensors. This study proposed the concept of dynamic observation capability index (DOCI), which denotes the continuously changing observation performance of diverse sensors in various applications. A higher DOCI demonstrates stronger observation capability. The DOCI model consists of five subcapabilities: spatial–temporal covering capabilities (Coverage), thematic observation capability (Theme), environmental capability (Radiation), attribute capability (SpaceTime), and quality capability (Accuracy). We discussed the assessment methods on the basis of the DOCI model. To verify the proposed DOCI method, seven sensors (AVHRR/3, BGIS-2000, Hyperion, MERSI-1, MODIS, OLI, and SeaWiFS) were used in four different observation task scenarios: normalized difference vegetation index measurement, snow cover monitoring, oil spill detection, and vegetation-type mapping. The results showed that the changes in the observation capability of different sensors in different scenarios can be effectively assessed and modeled using the DOCI index, thus aiding in the scientific pre-evaluation of homogeneous optical sensors. DOCI can also be used as a quantitative, comprehensive, and all-purpose prior assessment method in web-based sensor planning.
Autors: Chen, N.;Zhang, X.;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Feb 2014, volume: 7, issue:2, pages: 515 - 530
Publisher: IEEE
 
» A Fast Algorithm Based on SRFFT for Length DFTs
Abstract:
In this brief, we present a fast algorithm for computing length- discrete Fourier transforms (DFT). The algorithm divides a DFT of size- decimation in frequency into one length- DFT and two length- DFTs. The length- sub-DFT is recursively decomposed decimation in frequency, and the two size- sub-DFTs are transformed into two dimension and the terms with the same rotating factor are arranged in a column. Thus, the scaled DFTs (SDFTs) are obtained, simplifying the real multiplications of the proposed algorithm. A further improvement can be achieved by the application of radix-2/8, modified split-radix FFT (MSRFFT), and Wang's algorithm for computing its length- and length- sub-DFTs. Compared with the related algorithms, a substantial reduction of arithmetic complexity and more accurate precision are obtained.
Autors: Zheng, W.;Li, K.;Li, K.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Feb 2014, volume: 61, issue:2, pages: 110 - 114
Publisher: IEEE
 
» A Fast Color Information Setup Using EP-Like PSO for Manipulator Grasping Color Objects
Abstract:
A fast color information setup based on evolutionary programming (EP) like particles swarm optimization (EPSO) for the manipulator control system is examined in this paper. The first step for a manipulator to grasp and place color objects into the correct location is to correctly identify the RGB or the corresponding hue, saturation, value (HSV) color model. The commonly used method to determine the thresholds of HSV range is manual tuning, but it is time-consuming to find the best boundary to segment the color image. This paper proposes a new method to learn color information, which is executed by semiautomatic learning. At first, the watershed algorithm incorporates user interactions to segment the color image and obtain the target image. Then, the comparison between the target image and the original image is utilized to build a lookup table (LUT) of color information, where three HSV thresholds are learned by PSO methods. Because the convergence speed of well-known PSO algorithms is slow and may be stuck in the local minimum, we present the EPSO method realized by applying EP to the PSO method. Moreover, a novel approach is investigated to escape the local minimum supposing the particles are stuck in the local minimum. Finally, both the numerical and experimental results demonstrate that the developed approach can not only rapidly learn the thresholds to segment a color image but can also jump out the local minimum.
Autors: Li, T.-H.S.;Yin-Hao Wang;Ching-Chang Chen;Chih-Jui Lin;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Feb 2014, volume: 10, issue:1, pages: 645 - 654
Publisher: IEEE
 
» A Fast HEVC Inter CU Selection Method Based on Pyramid Motion Divergence
Abstract:
The newly developed HEVC video coding standard can achieve higher compression performance than the previous video coding standards, such as MPEG-4, H.263 and H.264/AVC. However, HEVC's high computational complexity raises concerns about the computational burden on real-time application. In this paper, a fast pyramid motion divergence (PMD) based CU selection algorithm is presented for HEVC inter prediction. The PMD features are calculated with estimated optical flow of the downsampled frames. Theoretical analysis shows that PMD can be used to help selecting CU size. A nearest neighboring like method is used to determine the CU splittings. Experimental results show that the fast inter prediction method speeds up the inter coding significantly with negligible loss of the peak signal-to-noise ratio.
Autors: Xiong, J.;Li, H.;Wu, Q.;Meng, F.;
Appeared in: IEEE Transactions on Multimedia
Publication date: Feb 2014, volume: 16, issue:2, pages: 559 - 564
Publisher: IEEE
 
» A four-pixel single-photon pulse-position array fabricated from WSi superconducting nanowire single-photon detectors
Abstract:
We demonstrate a scalable readout scheme for an infrared single-photon pulse-position camera consisting of WSi superconducting nanowire single-photon detectors. For an N × N array, only 2 × N wires are required to obtain the position of a detection event. As a proof-of-principle, we show results from a 2 × 2 array.
Autors: Verma, V.B.;Horansky, R.;Marsili, F.;Stern, J.A.;Shaw, M.D.;Lita, A.E.;Mirin, R.P.;Nam, S.W.;
Appeared in: Applied Physics Letters
Publication date: Feb 2014, volume: 104, issue:5, pages: 051115 - 051115-4
Publisher: IEEE
 
» A Framework for Land Cover Classification Using Discrete Return LiDAR Data: Adopting Pseudo-Waveform and Hierarchical Segmentation
Abstract:
Acquiring current, accurate land-use information is critical for monitoring and understanding the impact of anthropogenic activities on natural environments. Remote sensing technologies are of increasing importance because of their capability to acquire information for large areas in a timely manner, enabling decision makers to be more effective in complex environments. Although optical imagery has demonstrated to be successful for land cover classification, active sensors, such as light detection and ranging (LiDAR), have distinct capabilities that can be exploited to improve classification results. However, utilization of LiDAR data for land cover classification has not been fully exploited. Moreover, spatial–spectral classification has recently gained significant attention since classification accuracy can be improved by extracting additional information from the neighboring pixels. Although spatial information has been widely used for spectral data, less attention has been given to LiDAR data. In this work, a new framework for land cover classification using discrete return LiDAR data is proposed. Pseudo-waveforms are generated from the LiDAR data and processed by hierarchical segmentation. Spatial features are extracted in a region-based way using a new unsupervised strategy for multiple pruning of the segmentation hierarchy. The proposed framework is validated experimentally on a real dataset acquired in an urban area. Better classification results are exhibited by the proposed framework compared to the cases in which basic LiDAR products such as digital surface model and intensity image are used. Moreover, the proposed region-based feature extraction strategy results in improved classification accuracies in comparison with a more traditional window-based approach.
Autors: Jung, J.;Pasolli, E.;Prasad, S.;Tilton, J.C.;Crawford, M.M.;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Feb 2014, volume: 7, issue:2, pages: 491 - 502
Publisher: IEEE
 
» A Framework for Making Face Detection Benchmark Databases
Abstract:
The images in face detection benchmark databases are mostly taken by consumer cameras, and thus are constrained by popular preferences, including a frontal pose and balanced lighting conditions. A good face detector should consider beyond such constraints and work well for other types of images, for example, those captured by a surveillance camera. To overcome such constraints, a framework is proposed to transform a mother database, originally made for benchmarking face recognition, to daughter datasets that are good for benchmarking face detection. The daughter datasets can be customized to meet the requirements of various performance criteria; therefore, a face detector can be better evaluated on desired datasets. The framework is composed of two phases: 1) intrinsic parametrization and 2) extrinsic parametrization. The former parametrizes the intrinsic variables that affect the appearance of a face, and the latter parametrizes the extrinsic variables that determine how faces appear on an image. Experiments reveal that the proposed framework can generate not just data that are similar to those available from popular benchmark databases, but also those that are hardly available from existing databases. The datasets generated by the proposed framework offer the following advantages: 1) they can define the performance specification of a face detector in terms of the detection rates on variables with different variation scopes; 2) they can benchmark the performance on one single or multiple variables, which can be difficult to collect; and 3) their ground truth is available when the datasets are generated, avoiding the time-consuming manual annotation.
Autors: Hsu, G.-S.;Chu, T.-Y.;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Feb 2014, volume: 24, issue:2, pages: 230 - 241
Publisher: IEEE
 
» A gaas phononic crystal with shallow noncylindrical holes
Abstract:
A square lattice of shallow, noncylindrical holes in GaAs is shown to act as a phononic crystal (PnC) reflector. The holes are produced by wet-etching a GaAs substrate using a citric acid:H2O2 etching procedure and a photolithographed array pattern. Although nonuniform and asymmetric etch rates limit the depth and shape of the phononic crystal holes, the matrix acts as a PnC, as demonstrated by insertion loss measurements together with interferometric imaging of surface acoustic waves propagating on the GaAs surface. The measured vertical displacement induced by surface phonons compares favorably with finite-difference time-domain simulations of a PnC with rounded-square holes.
Autors: Petrus, J.A.;Mathew, R.;Stotz, J.A.H.;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Feb 2014, volume: 61, issue:2, pages: 364 - 368
Publisher: IEEE
 
» A Generalized Coupling Matrix Extraction Technique for Bandpass Filters With Uneven-Qs
Abstract:
In this paper, a vector fitting (VF) based analytical extraction method, which is capable of accurately extracting the coupling matrix and the uneven unloaded Qs of each electric resonators of a filter, is presented. Having had the complex poles and residues determined using VF, the coupling matrix can be obtained by a sequence of complex orthogonal transformations. As a side product, the unloaded Qs for each resonator will be directly obtained from the complex diagonal elements of the coupling matrix. To demonstrate the effectiveness of the proposed method, an ideal demonstrative example along with two practical challenging filter tuning examples, namely, an eight-pole dual-mode dielectric filter and an eight-pole dual-mode predistortion filter, are demonstrated. An excellent match between the responses of the measured data and those from the extracted coupling matrix with actual unloaded Q factors can be seen.
Autors: Hu, H.;Wu, K.-L.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Feb 2014, volume: 62, issue:2, pages: 244 - 251
Publisher: IEEE
 
» A Generalized Framework for Optimal Sizing of Distributed Energy Resources in Micro-Grids Using an Indicator-Based Swarm Approach
Abstract:
In this paper, a generalized double-shell framework for the optimal design of systems managed optimally according to different criteria is developed. Optimal design is traditionally carried out by means of minimum capital and management cost formulations and does not typically consider optimized operation. In this paper, the optimized multiobjective management is explicitly considered into the design formulation. The quality of each design solution is indeed defined by the evaluation of operational costs and capital costs. Besides, the assessment of the operational costs term is deduced by means of the solution of a multiobjective optimization problem. Each design solution is evaluated using the outcomes of a multiobjective optimization run: a Pareto hyper-surface in the n-dimensional space of the operational objectives. In the literature, commonly the evaluation of each design solution is carried out based on an approximate evaluation of the operational costs, not considering the real multiobjective optimized management. In this paper, such assessment is carried out using a suitable convergence indicator typically used for multiobjective optimization algorithms. The application is devoted to the problem of optimal sizing of distributed energy resources in medium voltage or low voltage microgrids. For this problem, the identification of the multiple operational impacts comes along with the solution of the optimal unit commitment of distributed generators. After the introductory section, the problem formulation is presented and an interesting application of the considered approach to the design of distributed energy sources in a microgrid is shown.
Autors: Di Silvestre, M.L.;Graditi, G.;Sanseverino, E.R.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Feb 2014, volume: 10, issue:1, pages: 152 - 162
Publisher: IEEE
 
» A Generalized Power Control Approach in ABC Frame for Modular Multilevel Converter HVDC Links Based on Mathematical Optimization
Abstract:
This paper presents a generalized and versatile control approach using Lagrange multipliers in the ABC frame for a modular multilevel converter-based HVDC system. The methodology is capable of analytically obtaining desired operative conditions by calculating the differential current references previously established by the constraints in the optimization formulation, while obtaining the result with minimum: 1) differential current oscillations or 2) capacitive phase-energy oscillations . Furthermore, the energy distribution inside the MMC (i.e., the capacitive phase average energy sum and difference ) is being regulated by means of the constraint definitions. The optimization yields a differential current reference in “abc” coordinates with a similar structure to instantaneous power theories: as the addition of the product between varying conductances and the MMC internal dynamics input voltages (i.e., the dc bus voltage and the MMC load electromotice force (emf) on the one hand; and a contribution proportional to the ac load power on the other. Both the objective function minimization and the energy constraints are achieved with one single current reference resulting from the optimization process, without the application of linear superposition techniques.
Autors: Bergna, G.;Garces, A.;Berne, E.;Egrot, P.;Arzande, A.;Vannier, J.-C.;Molinas, M.;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Feb 2014, volume: 29, issue:1, pages: 386 - 394
Publisher: IEEE
 
» A Group Incremental Approach to Feature Selection Applying Rough Set Technique
Abstract:
Many real data increase dynamically in size. This phenomenon occurs in several fields including economics, population studies, and medical research. As an effective and efficient mechanism to deal with such data, incremental technique has been proposed in the literature and attracted much attention, which stimulates the result in this paper. When a group of objects are added to a decision table, we first introduce incremental mechanisms for three representative information entropies and then develop a group incremental rough feature selection algorithm based on information entropy. When multiple objects are added to a decision table, the algorithm aims to find the new feature subset in a much shorter time. Experiments have been carried out on eight UCI data sets and the experimental results show that the algorithm is effective and efficient.
Autors: Jiye Liang;Feng Wang;Chuangyin Dang;Yuhua Qian;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Feb 2014, volume: 26, issue:2, pages: 294 - 308
Publisher: IEEE
 
» A High Performance and Energy-Efficient Cold Data Eviction Algorithm for 3D-TSV Hybrid ReRAM/MLC NAND SSD
Abstract:
A hybrid 3D-TSV ReRAM/MLC NAND SSD with cold data eviction (CDE) algorithm is proposed. In the proposed hybrid SSD, the lifetime and energy consumption are dominated by MLC NAND flash memory due to ReRAM's high endurance and low power consumption. In addition, partial page overwrites are possible in ReRAM. Thus, the write accesses to MLC NAND flash memory are largely reduced by storing hot data in ReRAM. As a result, the SSD energy consumption decreases and the lifetime is prolonged. With the CDE algorithm, a page-level adaptive data migration is achieved, which is transparent to the file system. Compared to the previous work, 8-times write throughput increase, 83% energy reduction and 6.5-times longer longevity are achieved with 3D-TSV technology. Moreover, from the experimental results, the data eviction should be triggered when ReRAM free space ratio decreases to a range of 8%–20%. Hence, the eviction frequency is adaptive to the data pattern in the hybrid SSD. The experimental results also suggest the requirements for ReRAM. To obtain the best effect, both the read and write latency of ReRAM should be below 3 s for 512 Bytes.
Autors: Sun, C.;Miyaji, K.;Johguchi, K.;Takeuchi, K.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Feb 2014, volume: 61, issue:2, pages: 382 - 392
Publisher: IEEE
 
» A High Power-Efficiency D-Band Frequency Tripler MMIC With Gain Up to 7 dB
Abstract:
A novel frequency tripler consisting of a harmonics generating stage and a converting stage is proposed. A common-emitter transistor in the first stage is used to produce mainly the first to third harmonics, while, a common-emitter transistor in the second stage converts simultaneously the first and the second harmonics into the third harmonic, and also amplifies the third harmonic at the input. The third harmonics obtained from different mechanisms add in favorably phase, and consequently improving the tripler's conversion gain. A proof-of-concept circuit is designed and manufactured in a 0.25 m InP DHBT Technology. The tripler has a conversion gain between 0 dB to 7 dB in the output frequency range from 110 to 155 GHz. It demonstrates also up to 30 dBc rejection ratio of the undesired first, the second and the fourth harmonics. The tripler consumes a dc power of only 45 mW, and achieves a state-of-the-art peak power efficiency of 20.2%, which to the authors' knowledge, is the highest obtained among triplers with positive gain published so far.
Autors: Bao, M.;Kozhuharov, R.;Zirath, H.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Feb 2014, volume: 24, issue:2, pages: 123 - 125
Publisher: IEEE
 
» A Large Piston Displacement MEMS Mirror With Electrothermal Ladder Actuator Arrays for Ultra-Low Tilt Applications
Abstract:
A large displacement piston motion micromirror is designed, fabricated, and tested with device features tuned to applications requiring ultralow tilt. The fabricated MEMS mirror is based on electrothermal actuation and has a footprint of 1.9 mm 1.9 mm with a mirror aperture of 1 mm. The application optimized device holds key features of ultralow maximum tilt of 0.25 and a strongly linear motion of 90 achievable at only 1.2 V. This device is further characterized in an interferometric system to determine the piston mode and the accurate piston displacement as a function of voltage, power, and frequency.
Autors: Samuelson, S.R.;Xie, H.;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Feb 2014, volume: 23, issue:1, pages: 39 - 49
Publisher: IEEE
 
» A Large-Scale Study of the Time Required to Compromise a Computer System
Abstract:
A frequent assumption in the domain of cybersecurity is that cyberintrusions follow the properties of a Poisson process, i.e., that the number of intrusions is well modeled by a Poisson distribution and that the time between intrusions is exponentially distributed. This paper studies this property by analyzing all cyberintrusions that have been detected across more than 260,000 computer systems over a period of almost three years. The results show that the assumption of a Poisson process model might be unoptimalâthe log-normal distribution is a significantly better fit in terms of modeling both the number of detected intrusions and the time between intrusions, and the Pareto distribution is a significantly better fit in terms of modeling the time to first intrusion. The paper also analyzes whether time to compromise (TTC) increase for each successful intrusion of a computer system. The results regarding this property suggest that time to compromise decrease along the number of intrusions of a system.
Autors: Holm, Hannes;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Feb 2014, volume: 11, issue:1, pages: 2 - 15
Publisher: IEEE
 
» A Lattice-Reduction-Aided Max-Log List Demapper for Coded MIMO Receivers
Abstract:
The max-log list demapper has been widely employed in the implementations of a coded multiple-input–multiple-output (MIMO) receiver, where only a candidate list of signal vectors is examined in the likelihood-ratio calculation to reduce complexity. Traditionally, the candidate list is generated in the original-lattice domain, which, unfortunately, results in severe degradation in the performance of the demapper if the channel is in ill-condition. In this paper, two new lattice-reduction-aided max-log list demappers are proposed, i.e., one for an iterative receiver and the other for a noniterative receiver. With similar complexity, the proposed demappers provide significant gains over existing demappers, particularly for the cases with a small list size and/or under a spatially correlated channel, due to the new algorithms for the generation of the candidate list. In addition, for the iterative receiver, the prior information coming out of the decoder is exploited to lower the complexity of the demapper.
Autors: Hsieh, T.-J.;Sheen, W.-H.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Feb 2014, volume: 63, issue:2, pages: 664 - 673
Publisher: IEEE
 
» A Linear Time-Over-Threshold Digitizing Scheme and Its 64-channel DAQ Prototype Design on FPGA for a Continuous Crystal PET Detector
Abstract:
We propose a practical general method, called the linear time-over-threshold (linear TOT) scheme, for nuclear pulse amplitude digitization aiming at providing a high degree of integration for a high-channel count detector system. The most critical technique in the scheme is that for a different particle detector and diverse pulse shaping, how to produce the time-varying dynamic threshold voltage, which enables the linear conversion from the peak amplitude of nuclear pulse to the TOT time width. Compared with the normal time-over-threshold method for pulse height digitizing, the linear TOT has a strict linearity, large measurable signal dynamic range, and good signal-to-noise ratio. Using the scheme, we design a prototype of a field-programmable gate-array (FPGA)-based 64-channel data-acquisition (DAQ) system for a continuous crystal poistron emission tomography detector. The system only consists of 64-channel active RC integrators and voltage comparators, a shared dynamic threshold generating circuit, and an FPGA. The physical size of the system is so small that it could be attached on the base of the PMT. The preliminary test results show that the nonlinearity between pulse amplitude and TOT time width is about 0.01%, and the prototype could achieve an energy resolution of 12.3% by coincident spectrum measurement, which is better than the result (14.6%) obtained using our previous homemade DAQ system designed with a normal analog-to-digital converter technique. The design proves that the linear TOT scheme is an effective solution for a high-channel count digitizing system in nuclear detection, not only for its high performance, but also for a high degree of integration.
Autors: Yonggang, W.;Xinyi, C.;Deng, L.;Wensong, Z.;Chong, L.;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Feb 2014, volume: 61, issue:1, pages: 99 - 106
Publisher: IEEE
 
» A Long-Stroke Nanopositioning Control System of the Coplanar Stage
Abstract:
With the continuing trend toward device miniaturization in many engineering and scientific fields, the need to accomplish highly precise measurements at the micro- or nanoscale has emerged as a critical concern. This paper presents a high-precision motion control system for the nanopositioning of a coplanar stage driven by two commercial ultrasonic motors. The motor drive provides three main driving modes, namely ac, Gate, and dc, for millimeter, micrometer, and nanometer displacements, respectively. The displacement of each axis stage is sensed using a linear diffraction grating interferometer (LDGI) with a nanometer resolution. To compensate for the effects of the variable friction force during stage motion, the gains of the proportional–integral–derivative controller used to regulate the stage motion are tuned adaptively by a back propagation neural network (BPNN) based on the feedback signals provided by the LDGI. Furthermore, to obtain a high-accuracy positional motion, the error compensation strategy is implemented to eliminate the systematic errors of the stage with error budget. The error budget is obtained by positioning error calibration using a laser interferometer, which optical axis is detected by a quadrant photodetector (QPD) to ensure no cosine error. The positioning accuracy of the proposed system is evaluated by performing a series of contouring experiments. The results demonstrate that the system achieves a nanometer level of accuracy and resolution and is, therefore, a suitable solution for micro-coordinate measuring machine, microlithography, and micromachining applications.
Autors: Wang, H.-Y.;Fan, K.-C.;Ye, J.-K.;Lin, C.-H.;
Appeared in: IEEE/ASME Transactions on Mechatronics
Publication date: Feb 2014, volume: 19, issue:1, pages: 348 - 356
Publisher: IEEE
 
» A Low Phase Noise Oscillator Principled on Transformer-Coupled Hard Limiting
Abstract:
Reduced phase noise conversion in a monolithic oscillator suitable for basestation applications is realized by hard limiting and subsequently restoring the resonating waveform. Overdriven transistors hard limit the drain voltage swing and it is shown analytically that this desensitizes the oscillation phase to circuit noise. A pair of tuned, 1:2 step-up transformers in the feedback path restore the fundamental frequency component with sufficient gain to overdrive the transistors forming the oscillator core, with greater selectivity than an equivalent LC tank. The 8 GHz, 65 nm CMOS oscillator prototype targeting the GSM-900 base-station specification consumes 32 mA from 1.5 V. Normalized to 915 MHz, the phase noise measured at 1 MHz offset is –147.7 dBc/Hz, validating predictions from theory and simulation. The measured frequency pushing is less than 16 MHz/V.
Autors: Visweswaran, A.;Staszewski, R.B.;Long, J.R.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2014, volume: 49, issue:2, pages: 373 - 383
Publisher: IEEE
 
» A Low Power Light Weight Wireless Multichannel Microsystem for Reliable Neural Recording
Abstract:
This paper reports on design and development of a reliable, single-chip, multichannel wireless biotelemetry microsystem intended for extracellular neural recording from awake, and behaving small animal models. The system requirements for reliable neural recording are identified and the inherently conflicting requirements of low power and reliability are addressed at architectural and circuit levels. The 2.85 3.84 mm , mixed-signal ASIC is fabricated in a 0.5 m 2P3M n-well standard CMOS process; and integrates a low-noise front-end, programmable digital controller, an RF modulator, and an RF power amplifier at the ISM band of 433 MHz on a single-chip. The microsystem, incorporating the ASIC, features 9-channel, is programmable, weighs 2.2 g (including batteries) and has dimensions of 2.2 1.1 0.5 cm . The transmitter consumes 5 mW and has a measured input referred voltage noise of 4.58 , 6.20 , and 7.81 at transmission distances of 3 m, 10 m, and 20 m, respectively. The measured inter-channel crosstalk is less than 3.5% and battery life is about an hour. The presented biotelemetry system has been successfully used in two in-vivo neural recording experiments: i) from the antennas of a freely roaming South-American cockroach, and ii) from the hippocampus of a- awake and mobile rat.
Autors: Borna, A.;Najafi, K.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2014, volume: 49, issue:2, pages: 439 - 451
Publisher: IEEE
 
» A Low-RCS and High-Gain Partially Reflecting Surface Antenna
Abstract:
We propose a novel design to reduce the radar cross section (RCS) and enhance the gain of a patch antenna by using partially reflecting surface (PRS). The PRS consists of two layers of metallic patterns on both sides of a dielectric slab. The metallic pattern on the bottom side is utilized to construct Fabry-Perot resonance cavity with ground plane of a patch antenna, while it is designed to absorb most of the incident wave on the top side. The PRS can enable the patch antenna to simultaneously achieve high gain and low RCS. Measurement results show that the antenna gain is enhanced by about 6.5 dB at 11.5 GHz, and its RCS is dramatically reduced in a broad frequency range from 6 to 14 GHz, compared with the traditional patch antenna without the PRS.
Autors: Pan, W.;Huang, C.;Chen, P.;Ma, X.;Hu, C.;Luo, X.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2014, volume: 62, issue:2, pages: 945 - 949
Publisher: IEEE
 
» A MapReduce Technique to Mosaic Continental-Scale Weather Radar Data in Real-Time
Abstract:
It is necessary to create continental-scale mosaics of radar data in real-time for applications ranging from precipitation estimation, hail diagnosis and tornado warnings to public awareness. Because of the high temporal and spatial resolution of data available from the United States' network of weather radars, creating radar mosaics in real-time has been possible only through compromises on the quality, timeliness or resolution of the mosaics. MapReduce is a programming model that can be employed for processing and generating large data sets by distributing parallel computations and data storage across a distributed cluster of machines. In this paper, a MapReduce approach to computing radar mosaics on a distributed cluster of compute nodes is presented. The approach is massively scalable, and is able to create high-resolution 3D radar mosaics over the Continental United States in real-time.
Autors: Lakshmanan, V.;Humphrey, T.W.;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Feb 2014, volume: 7, issue:2, pages: 721 - 732
Publisher: IEEE
 
» A Mathematical Framework for the Registration and Analysis of Multi-Fascicle Models for Population Studies of the Brain Microstructure
Abstract:
Diffusion tensor imaging (DTI) is unable to represent the diffusion signal arising from multiple crossing fascicles and freely diffusing water molecules. Generative models of the diffusion signal, such as multi-fascicle models, overcome this limitation by providing a parametric representation for the signal contribution of each population of water molecules. These models are of great interest in population studies to characterize and compare the brain microstructural properties. Central to population studies is the construction of an atlas and the registration of all subjects to it. However, the appropriate definition of registration and atlasing methods for multi-fascicle models have proven challenging. This paper proposes a mathematical framework to register and analyze multi-fascicle models. Specifically, we define novel operators to achieve interpolation, smoothing and averaging of multi-fascicle models. We also define a novel similarity metric to spatially align multi-fascicle models. Our framework enables simultaneous comparisons of different microstructural properties that are confounded in conventional DTI. The framework is validated on multi-fascicle models from 24 healthy subjects and 38 patients with tuberous sclerosis complex, 10 of whom have autism. We demonstrate the use of the multi-fascicle models registration and analysis framework in a population study of autism spectrum disorder.
Autors: Taquet, M.;Scherrer, B.;Commowick, O.;Peters, J.M.;Sahin, M.;Macq, B.;Warfield, S.K.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Feb 2014, volume: 33, issue:2, pages: 504 - 517
Publisher: IEEE
 
» A Mathematical Model of Cellular Metabolism During Ischemic Stroke and Hypothermia
Abstract:
Stroke is a major cause of death and disability worldwide. Therapeutic hypothermia is a potentially useful neuroprotective treatment. A mathematical model of brain metabolism during stroke is extended here to simulate the effect of hypothermia on cell survival. Temperature decreases were set to reduce chemical reaction rates and slow diffusion through ion channels according to the rule. Heat delivery to tissues was set to depend on metabolic heat generation rate and perfusion. Two cooling methods, scalp and vascular, were simulated to approximate temperature variation in the brain during treatment. Cell death was assumed to occur at continued cell membrane depolarization. Simulations showed that hypothermia to 34.5 °C induced within 1–1.5 h of stroke onset could extend cell survival time by at least 5 h in tissue with perfusion reduced by 80% of normal. There was good agreement between simulated metabolite dynamics and those reported in rat model studies.
Autors: Orlowski, P.;McConnell, F.K.;Payne, S.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Feb 2014, volume: 61, issue:2, pages: 484 - 490
Publisher: IEEE
 
» A Mean Field Game Synthesis of Initial Mean Consensus Problems: A Continuum Approach for Non-Gaussian Behavior
Abstract:
This technical note presents a continuum approach to a non-Gaussian initial mean consensus problem via Mean Field (MF) stochastic control theory. In this problem formulation: (i) each agent has simple stochastic dynamics with inputs directly controlling its state's rate of change and (ii) each agent seeks to minimize by continuous state feedback its individual discounted cost function involving the mean of the states of all other agents. For this dynamic game problem, a set of coupled deterministic (Hamilton-Jacobi-Bellman and Fokker-Planck-Kolmogorov) equations is derived approximating the stochastic system of agents as the population size goes to infinity. In a finite population system (analogous to the MF LQG framework): (i) the resulting decentralized MF control strategies possess an -Nash equilibrium property where goes to zero as the population size approaches infinity and (ii) these MF control strategies steer each individual's state toward the initial state population mean which is reached asymptotically as time goes to infinity. Hence, the system with decentralized MF control strategies reaches mean-consensus on the initial state population mean asymptotically as time goes to infinity.
Autors: Nourian, M.;Caines, P.E.;Malhame, R.P.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Feb 2014, volume: 59, issue:2, pages: 449 - 455
Publisher: IEEE
 
» A Mechanism for the Crossing of Orthogonal Magnetic Wires in Multiferroic Nanomagnet Logic
Abstract:
We report time division multiplexing-based seven-phase clocking mechanism for the crossing of magnetic wires by in-plane multiferroic nanomagnet logic (m-NML). By reasonably setting hold time and sequence of applied stress (or voltage), the proposed multiferroic clocking ensures correct signal propagation of two orthogonal m-NML wires (or paths). The effects of magnetostrictive layer thickness on required seven-phase clock period and strain are investigated. Accordingly, a link scheme between early four-phase clocking and proposed seven-phase multiferroic clocking is developed by compressing seven-phase clock period. Thus, exact computation synchronization and pipelining in the entire NML circuit have been implemented. Finally, power consumption in the proposed m-NML crossing is discussed. The result shows that the m-NML signal crossing can be achieved with an energy dissipation of only about 533 aJ.
Autors: Yang, X.;Cai, L.;Zhang, B.;Zhang, M.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Feb 2014, volume: 61, issue:2, pages: 487 - 492
Publisher: IEEE
 
» A MEMS Based Electrochemical Vibration Sensor for Seismic Motion Monitoring
Abstract:
This paper presents a micro-electro-mechanical system (MEMS) based electrochemical vibration sensor for seismic detection. Simulations were conducted to analyze the effect of the insulating spacers thickness on the sensitivity of the devices. Then, devices with different insulating spacers thicknesses were fabricated based on MEMS processes. The devices sensitivity was confirmed by a customized experimental platform, verifying the simulation results. In addition, the device performance was characterized with a quantified bandwidth of 0.2–5 Hz with sensitivity of 30.2 V/ and a linear voltage output as a function of the input vibration amplitude (up to 10 mg). The devices noise was determined as at 1 Hz. A random-vibration testing in the laboratory environment was conducted, where response correlations among seven devices were calculated as , suggesting high device repeatability. A field test was conducted right above a subway line to detect the seismic motion caused by the train and test results showed that the performance of the proposed devices was comparable with that of the commercial product MET-1001. A field test was also conducted in a prairie to monitor natural seismic motions and experimental results indicated that the proposed electrochemical sensors can detect seismic motions in a lower frequency domain with an energy peak at around 0.3 Hz compared with conventional moving-coil seismic sensors with an energy peak at 3 Hz. This newly proposed vibration sensor may function as a promising seismic motion detecting device in the field of geophysical prospecting where low-frequency seismic motion detection is requested. $hfill[2013{hbox{-}}0208- $
Autors: Deng, T.;Chen, D.;Wang, J.;Chen, J.;He, W.;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Feb 2014, volume: 23, issue:1, pages: 92 - 99
Publisher: IEEE
 

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