Pages: 012345678910111213141516171819202122232425


Electrical and Electronics Engineering publications abstract of: 08-2013 sorted by title, page: 0
» “EChO” Reconfigurable Power Management Unit for Energy Reduction in Sleep-Active Transitions
Abstract:
A novel reconfigurable switched-capacitor “EChO” Power Management Unit is introduced for ultra-low power duty-cycled integrated systems (e.g., sensor nodes for critical event monitoring). “EChO” reduces the energy cost associated with sleep-to-active and active-to sleep transitions by 64% with an area overhead less than 1% and no impact on active mode operation. Analysis shows that approximately the same energy reduction is achieved over a very wide range of operating conditions and design constraints (e.g., ratio between flying and decoupling capacitances, granularity of the capacitor array). Measurements show 25–30% system power saving for a 65-nm testchip implementation of the “EChO” PMU powering a 16-kgate processing unit and a 2-kbit SRAM at 0.55-V voltage in active mode, assuming a 1-s wakeup cycle, 6.25–12.5% activity and a processing task of 250 cycles. The technique can be synergistically employed with traditional reconfiguration techniques that focus on efficiency in active mode (ignoring active-sleep transitions) to sum up the benefits.
Autors: Alioto, M.;Consoli, E.;Rabaey, J.M.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Aug 2013, volume: 48, issue:8, pages: 1921 - 1932
Publisher: IEEE
 
» “Multi-temperature” method for high-pressure sorption measurements on moist shales
Abstract:
A simple and effective experimental approach has been developed and tested to study the temperature dependence of high-pressure methane sorption in moist organic-rich shales. This method, denoted as “multi-temperature” (short “multi-T”) method, enables measuring multiple isotherms at varying temperatures in a single run. The measurement of individual sorption isotherms at different temperatures takes place in a closed system ensuring that the moisture content remains constant. The multi-T method was successfully tested for methane sorption on an organic-rich shale sample. Excess sorption isotherms for methane were measured at pressures of up to 25 MPa and at temperatures of 318.1 K, 338.1 K, and 348.1 K on dry and moisture-equilibrated samples. The measured isotherms were parameterized with a 3-parameter Langmuir-based excess sorption function, from which thermodynamic sorption parameters (enthalpy and entropy of adsorption) were obtained. Using these, we show that by taking explicitly into account water vapor as molecular species in the gas phase with temperature-dependent water vapor pressure during the experiment, more meaningful results are obtained with respect to thermodynamical considerations. The proposed method can be applied to any adsorbent system (coals, shales, industrial adsorbents) and any supercritical gas (e.g., CH4, CO2) and is particularly suitable for sorption measurements using the manometric (volumetric) method.
Autors: Gasparik, Matus;Ghanizadeh, Amin;Gensterblum, Yves;Krooss, Bernhard M.;
Appeared in: Review of Scientific Instruments
Publication date: Aug 2013, volume: 84, issue:8, pages: 085116 - 085116-9
Publisher: IEEE
 
» 0.5 V Start-Up 87% Efficiency 0.75 mm² On-Chip Feed-Forward Single-Inductor Dual-Output (SIDO) Boost DC-DC Converter for Battery and Solar Cell Operation Sensor Network Micro-Computer Integration
Abstract:
An on-chip low power single-inductor dual-output (SIDO) DC-DC boost converter is proposed for battery and solar cell operating sensor network applications. A proposed feed forward control determines the Ton/Toff ratio precisely for each output without any compensation or linear capacitor. This feature helps reduce the costs of the external components and utilize an inexpensive process technology. A test chip was fabricated by 190-nm flash-memory embedded micro-computers CMOS process technology and can achieve an efficiency of 87% with a small area size of just 0.75 mm². For solar cell operation, a 0.5 V start-up was achieved even with a high threshold voltage of 0.7 V with a proposed forward back biased charge pump. A constant voltage algorithm was implemented as a maximum power point tracking (MPPT) control. With this MPPT control, a solar cell with an open voltage of 1.03 V and a short current of 83 mA was able to charge a super capacitor of 0.4 F up to 5 V within 80 s.
Autors: Nakase, Y.;Hirose, S.;Onoda, H.;Ido, Y.;Shimizu, Y.;Oishi, T.;Kumamoto, T.;Shimizu, T.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Aug 2013, volume: 48, issue:8, pages: 1933 - 1942
Publisher: IEEE
 
» 150-Channel Four Wave Mixing Based Multiwavelength Brillouin-Erbium Doped Fiber Laser
Abstract:
A wide band tunable multiwavelength Brillouin-erbium fiber laser (BEFL) is developed. In this structure, the laser is formed between a double pass amplification box and a highly nonlinear fiber (HNLF), which acts as a virtual mirror, results in removing the reflective physical mirror from one side of the laser structure. A large number of Stokes and anti-Stokes lines are generated through cascading stimulated Brillouin scattering and inducing four wave mixing process inside the HNLF. Due to optimizing Brillouin and erbium doped fiber (EDF) pump powers, the Rayleigh back scattering is efficiently suppressed, and the generated BEFL wavelengths are free from self lasing cavity modes over a wide tuning range. At EDF pump power and Brillouin pump power of 100 mW and 3 dBm, respectively, up to 150 Stokes lines with wavelength spacing of 0.076 nm, and a tuning range of 40 nm were achieved.
Autors: Al-Alimi, A.W.;Yaacob, M.H.;Abas, A.F.;Mahdi, M.A.;Mokhtar, M.;Al-Mansoori, M.H.;
Appeared in: IEEE Photonics Journal
Publication date: Aug 2013, volume: 5, issue:4, pages: 1501010 - 1501010
Publisher: IEEE
 
» 2 80 Gbit/s DWDM Bidirectional Wavelength Reuse Optical Wireless Transmission
Abstract:
We demonstrate a practical 2 80 Gbit/s dense wavelength division multiplexing (DWDM) bidirectional short-range optical wireless link. The measured power penalties for the bidirectional transmission are less than 0.8 and 0.2 dB compared to the back-to-back link and the unidirectional transmission system, respectively. We also practically evaluate the impact of the offset angles between the optical transmission path and the building windows. The result shows that the power penalty is as small as 0.3 dB. This technology offers a great potential for applications in building-to-building inter-transmission as part of local/wide area networks.
Autors: Hsu, H.-Y.;Lu, W.C.;Minh, H.L.;Ghassemlooy, Z.;Yu, Y.-L.;Liaw, S.-K.;
Appeared in: IEEE Photonics Journal
Publication date: Aug 2013, volume: 5, issue:4, pages: 7901708 - 7901708
Publisher: IEEE
 
» 2-D Compact Model for Drain Current of Fully Depleted Nanoscale GeOI MOSFETs for Improved Analog Circuit Design
Abstract:
Compact models for MOS devices are extremely useful as they can be incorporated in circuit simulators with sufficient accuracy. We present for the first time a 2-D surface-potential-based compact model for the drain current of nanoscale germanium-on-insulator (GeOI) MOSFETs including the interface-trapped and fixed-oxide charge densities at both front- and back-gates. The proposed drain current model is accurate, computationally efficient, and suitable for circuit simulation in the nanometer regime because no iterative loop is used anywhere. The drain current model includes velocity saturation, channel length modulation, carrier mobility degradation, and also the drain-induced barrier lowering. The model shows excellent concordance with the reported experimental transfer characteristic curves for both the high and low drain voltages and also exhibits good agreement for derivatives of drain current when compared with our TCAD simulation data for GeOI devices with channel length of 30 nm over a wide range of gate and drain bias conditions. Furthermore, our studies reveal that GeOI devices outperform silicon-on-insulator (SOI) counterparts in terms of analog figures of merit, such as transconductance, voltage gain, transconductance generation factor, and cut-off frequency, except the output conductance.
Autors: Mondal, C.;Biswas, A.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Aug 2013, volume: 60, issue:8, pages: 2525 - 2531
Publisher: IEEE
 
» 2.0- Q-Switched Thulium-Doped Fiber Laser With Graphene Oxide Saturable Absorber
Abstract:
A compact Q-switched thulium-doped fiber laser (TDFL) operating near the 2.0- μm region is proposed and demonstrated. The proposed laser uses a 2-m-long thulium-doped fiber with a core absorption of 27 dB/m at 793 nm as the active medium and a graphene oxide (GO)-based saturable absorber (SA) as the Q-switching element. The SA is fabricated by optically depositing GO particles dissolved in distilled water onto the face of a fiber ferrule, which is then used to assemble the SA. The proposed TDFL is capable of generating pulses with a maximum repetition rate of 16.0 kHz and pulsewidths as narrow as 9.8 μs, as well as having maximum average output power and pulse energy of 0.3 mW and 18.8 nJ, respectively. The combination of the easily fabricated GO-based SA, together with the TDFL's ability to operate in the eye-safe region of 2.0 μm, gives the proposed Q-switched TDFL a high potential for a multitude of real-world applications, including range-finding, medicine, and spectroscopy.
Autors: Ahmad, H.;Zulkifli, A.Z.;Thambiratnam, K.;Harun, S.W.;
Appeared in: IEEE Photonics Journal
Publication date: Aug 2013, volume: 5, issue:4, pages: 1501108 - 1501108
Publisher: IEEE
 
» 2.0- Q-Switched Thulium-Doped Fiber Laser With Graphene Oxide Saturable Absorber
Abstract:
A compact Q-switched thulium-doped fiber laser (TDFL) operating near the 2.0- region is proposed and demonstrated. The proposed laser uses a 2-m-long thulium-doped fiber with a core absorption of 27 dB/m at 793 nm as the active medium and a graphene oxide (GO)-based saturable absorber (SA) as the Q-switching element. The SA is fabricated by optically depositing GO particles dissolved in distilled water onto the face of a fiber ferrule, which is then used to assemble the SA. The proposed TDFL is capable of generating pulses with a maximum repetition rate of 16.0 kHz and pulsewidths as narrow as 9.8 , as well as having maximum average output power and pulse energy of 0.3 mW and 18.8 nJ, respectively. The combination of the easily fabricated GO-based SA, together with the TDFL's ability to operate in the eye-safe region of 2.0 , gives the proposed Q-switched TDFL a high potential for a multitude of real-world applications, including range-finding, medicine, and spectroscopy.
Autors: Ahmad, H.;Zulkifli, A.Z.;Thambiratnam, K.;Harun, S.W.;
Appeared in: IEEE Photonics Journal
Publication date: Aug 2013, volume: 5, issue:4, pages: 1501108 - 1501108
Publisher: IEEE
 
» 2.5 Beta Methodology—Impact of “Zero SAIDI” Days
Abstract:
The IEEE Standard 1366-2003-2.5 Beta Methodology was developed to provide a methodology to define a Major Event Day (MED) with respect to distribution reliability performance. The method applies to utilities experiencing interruptions every day or just some days of the year.
Autors: Hann, N.;Ji, B.;Qureshi, A.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Aug 2013, volume: 28, issue:3, pages: 3517 - 3518
Publisher: IEEE
 
» 220–250-GHz Phased-Array Circuits in 0.13- SiGe BiCMOS Technology
Abstract:
Pub DtlThis paper describes the design of 220–250-GHz phased-array circuits in 0.13- BiCMOS technology. The design aspects of the active and passive devices that are used in the phased-array systems, such as balun, Wilkinson divider, and branch-line coupler, are presented in details. A millimeter-wave vector modulator is designed to support both amplitude and phase control for beam-forming applications. The designed circuits are integrated together to form a four-channel 220–250-GHz phased-array chip. Each channel exhibits 360 phase control with 18 dB of amplitude control. The entire chip draws 167 mA from a 3.3-V supply. The millimeter-wave phase shifting and the low-power consumption makes it ideal for highly integrated scalable beam-forming systems for both imaging, radiometry, and communication applications.
Autors: Elkhouly, M.;Glisic, S.;Meliani, C.;Ellinger, F.;Scheytt, J.C.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Aug 2013, volume: 61, issue:8, pages: 3115 - 3127
Publisher: IEEE
 
» 25-GHz-Spaced DWDM-PON With Mitigated Rayleigh Backscattering and Back-Reflection Effects
Abstract:
A novel 25-GHz-spaced dense wavelength-division multiplexing passive optical network (DWDM-PON) is proposed to improve the utilization of wavelength resource and mitigate the Rayleigh backscattering (RB) and back-reflection effects. A colorless optical network unit (ONU) is realized by remodulating the downstream (DS) signal via a gain-saturated reflective semiconductor optical amplifier (RSOA). Due to the simple interconnecting architecture at the remote node (RN), the DS and upstream (US) signals in each feed fiber (FF) are carried on different channels. Therefore, the RB and back-reflection effects are significantly reduced. The feasibility and merits of the proposed system are experimentally demonstrated with the error-free transmission of 10-Gb/s DS and 1.25-Gb/s US signals over a 25-km single-mode fiber.
Autors: Zhou, Z.;Xiao, S.;Qi, T.;Li, P.;Bi, M.;Hu, W.;
Appeared in: IEEE Photonics Journal
Publication date: Aug 2013, volume: 5, issue:4, pages: 7901407 - 7901407
Publisher: IEEE
 
» 28.8 dBm, High Efficiency, Linear GaN Power Amplifier With In-Phase Power Combining for IEEE 802.11p Applications
Abstract:
This letter presents a power amplifier (PA) for IEEE802.11p applications, adopting a new power combining technique in a 250 nm GaN process. The proposed technique is used to improve the drain efficiency (DE) across the output power levels and meet the stringent error vector magnitude (EVM) requirement without any complicated input and output networks. The PA is implemented with a fabricated GaN die using the chip-on-board (COB) technology and tested with 27 Mbps IEEE802.11p signal. It achieves 30.5 dB EVM at 28.8 dBm output power with a back-off DE of 22.4% at 30 V supply at 5.72 GHz without pre-distortion. It also maintains more than 22% DE through supply voltage control while meeting its linearity requirement across the wide range of output power levels. The proposed circuit technique is viable for improving efficiency and optimizing linearity with its simple architecture.
Autors: Choi, P.;Boon, C.C.;Mao, M.;Liu, H.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Aug 2013, volume: 23, issue:8, pages: 433 - 435
Publisher: IEEE
 
» 3-D Residual Eddy Current Field Characterisation: Applied to Diffusion Weighted Magnetic Resonance Imaging
Abstract:
Clinical use of the Stejskal–Tanner diffusion weighted images is hampered by the geometric distortions that result from the large residual 3-D eddy current field induced. In this work, we aimed to predict, using linear response theory, the residual 3-D eddy current field required for geometric distortion correction based on phantom eddy current field measurements. The predicted 3-D eddy current field induced by the diffusion-weighting gradients was able to reduce the root mean square error of the residual eddy current field to ~1 Hz. The model's performance was tested on diffusion weighted images of four normal volunteers, following distortion correction, the quality of the Stejskal–Tanner diffusion-weighted images was found to have comparable quality to image registration based corrections (FSL) at low b-values. Unlike registration techniques the correction was not hindered by low SNR at high b-values, and results in improved image quality relative to FSL. Characterization of the 3-D eddy current field with linear response theory enables the prediction of the 3-D eddy current field required to correct eddy current induced geometric distortions for a wide range of clinical and high b-value protocols.
Autors: O'Brien, K.;Daducci, A.;Kickler, N.;Lazeyras, F.;Gruetter, R.;Feiweier, T.;Krueger, G.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Aug 2013, volume: 32, issue:8, pages: 1515 - 1525
Publisher: IEEE
 
» 32 & 16 Years Ago
Abstract:
A summary of articles published in Computer 32 and 16 years ago.
Autors: Holmes, Neville;
Appeared in: Computer
Publication date: Aug 2013, volume: 46, issue:8, pages: 12 - 13
Publisher: IEEE
 
» 360 PPI Flip-Chip Mounted Active Matrix Addressable Light Emitting Diode on Silicon (LEDoS) Micro-Displays
Abstract:
In this paper, we describe the design and fabrication of 360 PPI flip-chip mounted active matrix (AM) addressable light emitting diode on silicon (LEDoS) micro-displays. The LEDoS micro-displays are self-emitting devices which have higher light efficiency than liquid crystal based displays (LCDs) and longer lifetime than organic light emitting diodes (OLEDs) based displays . The LEDoS micro-displays were realized by integrating monolithic LED micro-arrays and silicon-based integrated circuit using a flip-chip bonding technique. The active matrix driving scheme was designed on the silicon to provide sufficient driving current and individual controllability of each LED pixel. Red, green, blue and Ultraviolet (UV) LEDoS micro-displays with a pixel size of 50 m and pixel pitch of 70 m were demonstrated. With a peripheral driving board, the LEDoS micro-display panels were programmed to show representative images and animations.
Autors: Liu, Z.J.;Chong, W.C.;Wong, K.M.;Lau, K.M.;
Appeared in: Journal of Display Technology
Publication date: Aug 2013, volume: 9, issue:8, pages: 678 - 682
Publisher: IEEE
 
» 3D-2D Registration of Cerebral Angiograms: A Method and Evaluation on Clinical Images
Abstract:
Endovascular image-guided interventions (EIGI) involve navigation of a catheter through the vasculature followed by application of treatment at the site of anomaly using live 2D projection images for guidance. 3D images acquired prior to EIGI are used to quantify the vascular anomaly and plan the intervention. If fused with the information of live 2D images they can also facilitate navigation and treatment. For this purpose 3D-2D image registration is required. Although several 3D-2D registration methods for EIGI achieve registration accuracy below 1 mm, their clinical application is still limited by insufficient robustness or reliability. In this paper, we propose a 3D-2D registration method based on matching a 3D vasculature model to intensity gradients of live 2D images. To objectively validate 3D-2D registration methods, we acquired a clinical image database of 10 patients undergoing cerebral EIGI and established “gold standard” registrations by aligning fiducial markers in 3D and 2D images. The proposed method had mean registration accuracy below 0.65 mm, which was comparable to tested state-of-the-art methods, and execution time below 1 s. With the highest rate of successful registrations and the highest capture range the proposed method was the most robust and thus a good candidate for application in EIGI.
Autors: Mitrovic, U.;Spiclin, Z.;Likar, B.;Pernus, F.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Aug 2013, volume: 32, issue:8, pages: 1550 - 1563
Publisher: IEEE
 
» 3d-4f spin interaction induced giant magnetocaloric effect in zircon-type DyCrO4 and HoCrO4 compounds
Abstract:
We have investigated the influence of 3d-4f spin interaction on magnetic and magnetocaloric properties of DyCrO4 and HoCrO4 compounds by magnetization and heat capacity measurements. Both the compounds exhibit complicated magnetic properties and huge magnetic entropy change around the ferromagnetic transition due to the strong competition between ferromagnetic and antiferromagnetic superexchange interactions. For a field change of 8 T, the maximum values of magnetic entropy change (ΔSMmax), adiabatic temperature change (ΔTad), and refrigerant capacity (RC) reach 29 J kg-1 K-1, 8 K, and 583 J kg-1, respectively, for DyCrO4 whereas the corresponding values for HoCrO4 are 31 J kg-1 K-1, 12 K, and 622 J kg-1. ΔSMmax, ΔTad, and RC are also quite large for a moderate field change. The large values of magnetocaloric parameters suggest that the zircon-type DyCrO4 and HoCrO4 could be the potential magnetic refrigerant materials for liquefaction of hydrogen.
Autors: Midya, A.;Khan, N.;Bhoi, D.;Mandal, P.;
Appeared in: Applied Physics Letters
Publication date: Aug 2013, volume: 103, issue:9, pages: 092402 - 092402-5
Publisher: IEEE
 
» 60 GHz dual-band bandpass filter using LTCC
Abstract:
A dual-band bandpass filter with quasi-elliptic response using a substrate integrated waveguide for 60 GHz dual-band wireless communication systems is proposed. It is fabricated with standard low-temperature co-fired ceramic (LTCC) technology. The measured results indicate that the filter is operating at 59.78 and 61.56 GHz with fractional bandwidths of 2.1 and 2.2%, and minimum in-band insertion losses of 3.61 and 3.55 dB, respectively. Furthermore, the proposed filter exhibits an electrical size (including the CPW measurement pads) of 2.38λg ?? 3.14λg, where λg is the guided wavelength at 60 GHz.
Autors: Xu, X.;Wang, J.;Zhang, G.;
Appeared in: Electronics Letters
Publication date: Aug 2013, volume: 49, issue:16
Publisher: IEEE
 
» 64 μW pulsed terahertz emission from growth optimized InGaAs/InAlAs heterostructures with separated photoconductive and trapping regions
Abstract:
We present results on optimized growth temperatures and layer structure design of high mobility photoconductive Terahertz (THz) emitters based on molecular beam epitaxy grown In0.53Ga0.47As/In0.52Al0.48As multilayer heterostructures (MLHS). The photoconductive antennas made of these MLHS are evaluated as THz emitters in a THz time domain spectrometer and with a Golay cell. We measured a THz bandwidth in excess of 4 THz and average THz powers of up to 64 μW corresponding to an optical power-to-THz power conversion efficiency of up to 2 × 10-3.
Autors: Dietz, Roman J.B.;Globisch, Bjorn;Gerhard, Marina;Velauthapillai, Ajanthkrishna;Stanze, Dennis;Roehle, Helmut;Koch, Martin;Gobel, Thorsten;Schell, Martin;
Appeared in: Applied Physics Letters
Publication date: Aug 2013, volume: 103, issue:6, pages: 061103 - 061103-4
Publisher: IEEE
 
» 85-fJ Dissipated Energy Per Bit at 30 Gb/s Across 500-m Multimode Fiber Using 850-nm VCSELs
Abstract:
We present important progress in energy efficiency for oxide-confined 850-nm single mode and quasi single mode vertical-cavity surface-emitting lasers (VCSELs) suitable for optical interconnects. Error-free operation at 30 Gb/s across 500 m of multimode optical fiber is achieved with 85 fJ of dissipated energy per bit. At 25 Gb/s, the maximum multimode fiber distance is 1000 m. These VCSELs are presently the most energy efficient directly modulated light-sources for data transmission across multimode optical fiber distances up to 1 km.
Autors: Moser, P.;Lott, J.A.;Wolf, P.;Larisch, G.;Li, H.;Bimberg, D.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Aug 2013, volume: 25, issue:16, pages: 1638 - 1641
Publisher: IEEE
 
» Filtering for Networked Systems With Multiple Time-Varying Transmissions and Random Packet Dropouts
Abstract:
This paper is concerned with the filtering for networked systems with multiple time-varying transmissions and random packet dropouts. We design a remote filter for these two networked issues such that the filtering error system is exponentially stable and achieves a prescribed performance level. A switched system approach is used to model the multiple time-varying transmission process, and a set of stochastic variables are employed to describe the random packet dropout phenomenon. By the switched system theory and some stochastic analysis methods, a sufficient condition for the existence of the filter is derived in terms of linear matrix inequalities (LMIs). Moreover, the filter gains are determined by solving an optimization problem. Two numerical examples are given to illustrate the effectiveness of the proposed design method.
Autors: Zhang, D.;Wang, Q.-G.;Yu, L.;Shao, Q.-K.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Aug 2013, volume: 9, issue:3, pages: 1705 - 1716
Publisher: IEEE
 
» Implanted 4H-SiC -i-n Diodes: Forward Current Negative Temperature Coefficient
Abstract:
Vertical 4H-Silicon Carbide -i-n diodes are obtained by a selective area ion implantation of the anodes. These diodes are fabricated with identical steps except post-implantation annealing that is 1650 /25 min and 1950 /5 min. Electrical characterization in the temperature range 25 –290 is performed. The 1650 /25 min diodes have forward currents with a positive temperature coefficient. The 1950 /5 min diodes have forward current characteristics with a crossover point from a positive to a negative temperature coefficient that makes such characteristics almost stable versus temperature.
Autors: Nipoti, R.;Moscatelli, F.;De Nicola, P.;
Appeared in: IEEE Electron Device Letters
Publication date: Aug 2013, volume: 34, issue:8, pages: 966 - 968
Publisher: IEEE
 
» ?Hybrid Particle Swarm Optimization and Genetic Algorithm for Multi-UAV Formation Reconfiguration
Abstract:
The initial state of an Unmanned Aerial Vehicle (UAV) system and the relative state of the system, the continuous inputs of each flight unit are piecewise linear by a Control Parameterization and Time Discretization (CPTD) method. The approximation piecewise linearization control inputs are used to substitute for the continuous inputs. In this way, the multi-UAV formation reconfiguration problem can be formulated as an optimal control problem with dynamical and algebraic constraints. With strict constraints and mutual interference, the multi-UAV formation reconfiguration in 3-D space is a complicated problem. The recent boom of bio-inspired algorithms has attracted many researchers to the field of applying such intelligent approaches to complicated optimization problems in multi-UAVs. In this paper, a Hybrid Particle Swarm Optimization and Genetic Algorithm (HPSOGA) is proposed to solve the multi-UAV formation reconfiguration problem, which is modeled as a parameter optimization problem. This new approach combines the advantages of Particle Swarm Optimization (PSO) and Genetic Algorithm (GA), which can find the time-optimal solutions simultaneously. The proposed HPSOGA will also be compared with basic PSO algorithm and the series of experimental results will show that our HPSOGA outperforms PSO in solving multi-UAV formation reconfiguration problem under complicated environments.
Autors: Duan, H.;Luo, Q.;Shi, Y.;Ma, G.;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Aug 2013, volume: 8, issue:3, pages: 16 - 27
Publisher: IEEE
 
» ?They Said It Couldn?t Be Done, So We Did [History]
Abstract:
When it began is hard to say, but one thing is certain: The real electronics breakthrough for Danfoss came with the introduction of the VLT5 frequency converter in 1968. It was the first mass-produced device that could speed control a standard, 5-hp electric motor.
Autors: Stewart, P.;Brusso, B.;
Appeared in: IEEE Industry Applications Magazine
Publication date: Aug 2013, volume: 19, issue:4, pages: 9 - 77
Publisher: IEEE
 
» A 1 mJ/Frame Unified Media Application Processor With Dynamic Analog-Digital Mode Reconfiguration for Embedded 3D-Media Contents Processing
Abstract:
In this paper, a unified media application processor (UMAP) is presented for 2D/3D image analysis/synthesis applications on handheld devices. UMAP integrates parallel and sequential processing layers which consist of heterogeneous functional IPs for general media contents processing on today's application processors (AP). Based on the heterogeneous many-core platform, UMAP supports not only graphics and vision processing for real-time augmented reality (AR) but also disparity estimation and 3D display synthesis for 3D-view AR acceleration. A new concept of 3D-view AR which synthesizes 3D display contents from two vertically aligned stereo images and a self-constructed disparity map is introduced to achieve true realism for next generation mobile devices. For low-cost 3D-view AR processing, a homography-based disparity estimation (HDE) algorithm is proposed to construct a disparity map between two stereo images with small implementation overhead. For real-time and energy-efficient system organization, workload-balanced 3-stage pipelined architecture and a mixed-mode feature extraction engine (FEE) are also implemented in UMAP. The 3-stage pipelined system which consists of graphics, vision, and display operation stages reduces per-frame execution latency, while dynamic analog/digital mode reconfiguration based on mixed-mode FEE reduces per-frame energy dissipation, so real-time energy-efficient 3D-view AR can be realized in UMAP. FEE performs high-speed corner detection for vision processing based on four pairs of analog current contention logics (CCLs). Especially, a diode-connected current sensing stabilizer (CSS) in each CCL reduces minimum sensing current for corner detection, so average power consumed in CCL is reduced by 44.9%. In 2D or 3D-view AR processing, FEE with four CCLs replaces the parallel processing core cluster which is the most power hungry IP in UMAP, so 96.7% of cluster power and 99.1% of target detection time are saved in real operation. Based- on the 3-stage pipelined architecture with the dynamic mode reconfiguration technique, the entire UMAP achieves up to 64.4% of energy reduction compared to the previous state-of-the-art media processors in full operation.
Autors: Kim, H.-E.;Park, J.-S.;Yoon, J.-S.;Kim, S.-H.;Kim, L.-S.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Aug 2013, volume: 48, issue:8, pages: 1970 - 1985
Publisher: IEEE
 
» A 10-Bit 2-GS/s DAC-DDFS-IQ-Controller Baseband Enabling a Self-Healing 60-GHz Radio-on-Chip
Abstract:
A 10-bit 2-GS/s mixed-signal baseband (BB) circuit, which enables a self-healing 60-GHz 4-Gb/s radio-on-chip implemented in a 65-nm complementary metal–oxide semiconductor, is described. The BB circuit autonomously senses and optimizes transmitter (TX) , , and image suppression, reducing the yield loss because of process variations. On-chip test tones are generated using a 10-bit 2-GS/s current-steering digital-to-analog converter (DAC) and direct digital frequency synthesizer (DDFS). Using the generated test tones, the aforementioned impairments are measured by an envelope detector at the power amplifier output. Based on this information, the programmable digital IQ phase amplitude and offset controller (IQ_CTRL) in the BB circuit improves the TX image suppression from 32.4 to 42.6 dBc, and digital control signals generated by the on-chip self-healing controller heal the TX and from 9.5 to 13.2 dBm and from 32.5 to 40 dBc, respectively. In terms of achieving the target specifications, namely, TX image suppression , , and , healing increases yie- d on ten dies from 0% to 100%. The BB circuit consumes only 49 mW, of which 37 mW comes from the DACs and 12 mW from the DDFS and the IQ_CTRL.
Autors: D'Souza, S.;Hsiao, F.;Tang, A.;Tam, S.-W.;Berenguer, R.;Chang, M.-C.F.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Aug 2013, volume: 60, issue:8, pages: 457 - 461
Publisher: IEEE
 
» A 100 MHz Two-Phase Four-Segment DC-DC Converter With Light Load Efficiency Enhancement in CMOS
Abstract:
This paper describes a high switching frequency CMOS DC-DC converter employing phase shedding/segmentation and resonant gate drivers to improve light load efficiency. A novel output inductor network with positively coupled inductors between segments and negatively coupled inductors between phases is adopted in two-phase four-segment interleaved topology to improve effective inductance and reduce inductor current ripple. To limit the contribution of the gate driver to the total converter loss under light and medium loads, a new combined high-side and low-side resonant type gate driver with partially shared inductor is presented. The DC-DC converter is implemented in six-metal CMOS technology with 5 V power devices and occupies a total area of 2.55 mm 3.0 mm. It converts 4 V input to 1 to 3 V output with peak 1.78 A current under 100 MHz switching frequency. The measured peak efficiency is 77.4% at 5.95 W output power and the tracking mode bandwidth can reach up to 8 MHz. With resonant gate drivers, 5% efficiency improvement can be reached at 1 V output. Furthermore, the converter is able to maintain peak efficiency as the output current varies from 0.1 A to 1.86 A.
Autors: Peng, H.;Anderson, D;Hella, M.M.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Aug 2013, volume: 60, issue:8, pages: 2213 - 2224
Publisher: IEEE
 
» A 2-D Finite-Element Analysis for a Permanent Magnet Synchronous Motor Taking an Overhang Effect Into Consideration
Abstract:
In the two-dimensional (2-D) finite-element (FE) analysis, the overhang effect can be considered through an increase in the remanence flux density of the permanent magnet in order to reflect the increment of the air-gap flux density due to the overhang structure. However, a repetitive 2-D FE analysis was performed in order to match the air-gap flux density with it in the three-dimensional (3-D) FE analysis. The proposed method accurately accounts for the overhang effect without trial and error. From the results of the 3-D FE analysis, the validity of the proposed method is verified.
Autors: Woo, D.-K.;Lim, D.-K.;Yeo, H.-K.;Ro, J.-S.;Jung, H.-K.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Aug 2013, volume: 49, issue:8, pages: 4894 - 4899
Publisher: IEEE
 
» A 2.3 mW 10-bit 170 MS/s Two-Step Binary-Search Assisted Time-Interleaved SAR ADC
Abstract:
This paper presents the architecture of a 10b 170 MS/s two-step binary-search assisted time-interleaved SAR ADC. The front-end stage of this ADC is built with a 5b binary-search ADC, which is shared by two time-interleaved 6b SAR ADCs in the second-stage. The design does not use any static component such as op-amp or preamplifier that causes large dissipation of static power. DAC settling speed and power are also relaxed thanks to this architecture. Besides, the process insensitive asynchronous logic further reduces the delay of SA loop rather than using worst case delay cells to compensate the process variation problem. The ADC was fabricated in 65 nm CMOS and achieves 54.6 dB SNDR at 170 MS/s with only 2.3 mW of power consumption, leading to a FoM of 30.8 fJ/conversion-step.
Autors: Wong, S.-S.;Chio, U.-F.;Zhu, Y.;Sin, S.-W.;U, S.-P.;Martins, R.P.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Aug 2013, volume: 48, issue:8, pages: 1783 - 1794
Publisher: IEEE
 
» A 2.3 nJ/Frame Voice Activity Detector-Based Audio Front-End for Context-Aware System-On-Chip Applications in 32-nm CMOS
Abstract:
Advanced human-machine interfaces require improved embedded sensors that can seamlessly interact with the user. Voice-based communication has emerged as a promising interface for next generation mobile, automotive and hands-free devices. Presented here is such an audio front-end with Voice Activity Detection (VAD) hardware targeted for low-power embedded SoCs, featuring a 512 pt FFT, programmable filters, noise floor estimator and a decision engine which has been fabricated in 32 nm CMOS. The dual- , dual-frequency design allows the core datapath to scale to near-threshold voltage (NTV), where power consumption is less than 50 uW. At peak energy efficiency, the core can process audio data at 2.3 nJ/frame—a 9.4X improvement over nominal voltage conditions.
Autors: Raychowdhury, A.;Tokunaga, C.;Beltman, W.;Deisher, M.;Tschanz, J.;De, V.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Aug 2013, volume: 48, issue:8, pages: 1963 - 1969
Publisher: IEEE
 
» A 23.5 GHz PLL With an Adaptively Biased VCO in 32 nm SOI-CMOS
Abstract:
A 23.5 GHz 32 nm SOI-CMOS PLL with 30% frequency tuning range features an adaptively biased VCO. The adaptive biasing scheme lowers the average PLL power consumption from 34 mW to 27.2 mW, while keeping the jitter below 1.3 RMS across all frequency bands.
Autors: Plouchart, J.-O.;Ferriss, M.;Natarajan, A.S.;Valdes-Garcia, A.;Sadhu, B.;Rylyakov, A.;Parker, B.D.;Beakes, M.;Babakhani, A.;Yaldiz, S.;Pileggi, L.;Harjani, R.;Reynolds, S.;Tierno, J.A.;Friedman, D.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Aug 2013, volume: 60, issue:8, pages: 2009 - 2017
Publisher: IEEE
 
» A 240-mW 2.1-GS/s 52-dB SNDR Pipeline ADC Using MDAC Equalization
Abstract:
This paper introduces multiplying digital-to-analog converter (MDAC) equalization, a digital correction technique for pipeline ADCs that corrects MDAC gain, settling, and other dynamic errors using successive digital FIR filters operating on sub-ADC output samples. This technique reduces the required MDAC residue amplifier (RA) bandwidth relative to the sampling frequency, thereby reducing ADC power. MDAC equalization is demonstrated in a 240-mW 2.1-GS/s ping-pong pipeline ADC in 40-nm CMOS where MDAC RA power is reduced from 175 to 53 mW by 70%. The ADC achieves 58 dB SNR and 52 dB SNDR.
Autors: Wu, J.;Chen, C.-Y.;Li, T.;He, L.;Liu, W.;Shih, W.-T.;Tsai, S.S.;Chen, B.;Huang, C.-S.;Hung, B.J.-J.;Hung, H.T.;Jaffe, S.;Tan, L.K.;Vu, H.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Aug 2013, volume: 48, issue:8, pages: 1818 - 1828
Publisher: IEEE
 
» A 3.1-GHz Class-F Power Amplifier With 82% Power-Added-Efficiency
Abstract:
This letter presents the first high-frequency, multi-harmonic-controlled , Class-F power amplifier (PA) implemented with a packaged GaN transistor. For PA design at high frequencies, parasitics of a packaged transistor significantly increase the difficulty of harmonic manipulation, compared to low-frequency cases. To overcome this issue, we propose a novel design methodology based on a three-stage, low-pass, output matching network, which is realized with transmission lines. This network provides optimal fundamental impedance and allows harmonic control up to the fourth order to enable an efficient Class-F behavior. The implemented PA exhibits a state-of-the-art performance at 3.1 GHz with a 82% PAE, 15 dB gain, and 10 W output power, indicating a clear advantage of this method over the conventional ones with extra parasitic compensators.
Autors: Chen, K.;Peroulis, D.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Aug 2013, volume: 23, issue:8, pages: 436 - 438
Publisher: IEEE
 
» A 325 GHz Quadrature Voltage Controlled Oscillator With Superharmonic-Coupling
Abstract:
We present a 325 GHz quadrature voltage controlled oscillator (QVCO) using 0.25 InP HBT technology and superharmonic coupling of two differential Colpitts VCOs. The individual VCOs exhibit about single-ended output power and 10 GHz frequency tuning range. The quadrature oscillation is successfully demonstrated with dc power consumption of 92.4 mW and phase imbalance less than at around 325 GHz.
Autors: Kim, J.-Y.;Song, H.-J.;Ajito, K.;Yaita, M.;Kukutsu, N.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Aug 2013, volume: 23, issue:8, pages: 430 - 432
Publisher: IEEE
 
» A 4.5 MGy TID-Tolerant CMOS Bandgap Reference Circuit Using a Dynamic Base Leakage Compensation Technique
Abstract:
The total-ionizing-dose (TID) radiation tolerance of bandgap references in deep-submicron CMOS technology is generally limited by the radiation introduced leakage current in diodes. An analysis of this phenomenon is given in this paper, and a dynamic base leakage compensation (DBLC) technique is proposed to improve the radiation hardness of a bandgap reference built in a standard 0.13 CMOS technology. A temperature coefficient of 15 from to 125 is measured before irradiation. The voltage variation from 0 to 100 is only 1 mV for an output voltage of 600 mV. Gamma irradiation assessment proves that the bandgap reference is tolerant to a total ionizing dose of at least 4.5 MGy. The output reference voltage exhibits a variation of less than 3% during the entire experiment, when the chip is irradiated by gamma ray at a dose rate of 27 kGy/h.
Autors: Cao, Y.;De Cock, W.;Steyaert, M.;Leroux, P.;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Aug 2013, volume: 60, issue:4, pages: 2819 - 2824
Publisher: IEEE
 
» A 57.5–90.1-GHz Magnetically Tuned Multimode CMOS VCO
Abstract:
This paper presents a magnetically tuned (MT) multimode VCO featuring an ultrawide frequency tuning range. A switched-triple-shielded transformer is proposed to change the magnetic coupling coefficient between the primary and secondary coils in the transformer tank to greatly increase the frequency tuning range of the dual-band VCO to cover the whole -band continuously. Fabricated in a 65-nm CMOS process, the MT-VCO measures a frequency tuning range of 41.1% from 57.5 to 90.1 GHz while consuming 7 to 9 mA at 1.2-V supply with chip area of 0.03 mm . The measured phase noises at 10-MHz offset from carrier frequencies of 58, 72.2, 80.5, and 90.1 GHz, are 107.4, 111.8, 107.8, and 105.1 dBc/Hz, respectively, which correspond to between 184.2 and 192.2 dBc/Hz.
Autors: Yin, J.;Luong, H.C.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Aug 2013, volume: 48, issue:8, pages: 1851 - 1861
Publisher: IEEE
 
» A 58-dBm -Band Limiter in Standard 0.25- BiCMOS Technology
Abstract:
Pub DtlA series of limiters have been developed for power levels up to 58 dBm in a standard 0.25- BiCMOS process. After a thorough analysis of general design tradeoffs, a figure-of-merit (FOM) for limiter technologies is introduced. This FOM indicates the necessity of a high current-to-capacitance ratio, which is obtained by exploiting the base-collector junction. Two designs were implemented for operation up to - and -band with optimized power capability for the respective frequency bands. The proposed designs avoid dedicated technologies like PIN-diodes or gas discharge tubes and thus enable integration of the limiter in a receiver front-end chip. The limiters have been designed based on a diode model, which was carefully extracted from measurements on a single diode cell. Reliability aspects, specific to limiters, are discussed. The measurements on the -band limiter showed that 58 dBm pulses with 10- length can be handled, which is similar to power levels obtained by commercial PIN diode limiters.
Autors: van Wanum, M.;van Vliet, F.E.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Aug 2013, volume: 61, issue:8, pages: 3034 - 3042
Publisher: IEEE
 
» A 6-b 1.6-GS/s ADC With Redundant Cycle One-Tap Embedded DFE in 90-nm CMOS
Abstract:
ADC-BASED serial link receivers are emerging in order to scale data rates over high attenuation channels. Embedding partial equalization inside the front-end ADC can potentially result in lowering the complexity of back-end DSP and/or decreasing the ADC resolution requirement, which results in a more energy-efficient receiver. This paper presents a 6-b 1.6-GS/s ADC with a novel embedded DFE structure. A redundant cycle technique is proposed for a time-interleaved SAR ADC, which relaxes the DFE feedback critical path delay with low power/area overhead. The 6-b prototype ADC with embedded one-tap DFE is fabricated in an LP 90-nm CMOS process and achieves 4.75-bits peak ENOB and 0.46 pJ/conv.-step FOM at a 1.6-GS/s sampling rate. Enabling the embedded DFE while operating at 1.6 Gb/s over a 46-in FR4 channel with 14-dB loss at Nyquist bandwidth opens a previously closed eye and allows for a 0.2 UI timing margin at a . Total ADC power including front-end T/Hs and reference buffers is 20.1 mW, and the core time-interleaved ADC occupies 0.24 mm area.
Autors: Tabasy, E.Z.;Shafik, A.;Huang, S.;Yang, N.H.-W.;Hoyos, S.;Palermo, S.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Aug 2013, volume: 48, issue:8, pages: 1885 - 1897
Publisher: IEEE
 
» A 65 nm Low-Power Adaptive-Coupling Redundant Flip-Flop
Abstract:
We propose a low-power redundant flip-flop to be operated with high reliability over 1 GHz clock frequency based on the low-power (ACFF) and the highly-reliable (BCDMR) flip-flops. Its power dissipation is almost equivalent to the transmission-gate FF at 10% data activity while paying 3 area penalty. Experiments by -particle and neutron irradiation reveal its highly-reliable operations with no error at 1.2 V and 1 GHz. We measured five different process corner chips by irradiation. Soft error rates are almost equivalent in these corner chips.
Autors: Masuda, M.;Kubota, K.;Yamamoto, R.;Furuta, J.;Kobayashi, K.;Onodera, H.;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Aug 2013, volume: 60, issue:4, pages: 2750 - 2755
Publisher: IEEE
 
» A 7–8.5 GHz High Performance MMIC HTS Josephson Mixer
Abstract:
A low-loss, low power consumption monolithic high-temperature superconducting (HTS) Josephson junction mixer at 7–8.5 GHz is presented. The mixer consists of a HTS (YBCO) bandpass filter for RF input, a lowpass filter for IF output and a LO resonator integrated with a single Josephson junction. All the passive and active devices are fabricated on a MgO substrate. Measurement result shows a conversion gain of at 40 K, and at 20 K. The IF output versus the RF input exhibits a wide linear range of conversion gains. The mixer has an extremely low LO power requirement at and a 50 nW power consumption.
Autors: Zhang, T.;Du, J.;Guo, Y.J.;Sun, X.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Aug 2013, volume: 23, issue:8, pages: 427 - 429
Publisher: IEEE
 
» A 7-bit, 1.4 GS/s ADC With Offset Drift Suppression Techniques for One-Time Calibration
Abstract:
This paper describes a digitally calibrated 7-bit, 1.4 GS/s flash analog-to-digital converter (ADC) implemented in 45-nm CMOS. The proposed offset drift suppression techniques for dynamic comparator and preamplifier make the ADC robust against environmental variation. As a result, once the ADC is calibrated at power up, no more calibration is necessary, even under VDD or temperature variations. The robustness is theoretically and experimentally verified. A calibration algorithm for doubling the ADC accuracy is also presented. The ADC occupies a small area of 0.085 and dissipates 33.24 mW at 1.4 GS/s from a 1.15 V supply.
Autors: Nakajima, Y.;Kato, N.;Sakaguchi, A.;Ohkido, T.;Miki, T.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Aug 2013, volume: 60, issue:8, pages: 1979 - 1990
Publisher: IEEE
 
» A 76–84-GHz 16-Element Phased-Array Receiver With a Chip-Level Built-In Self-Test System
Abstract:
Pub DtlThis paper presents a 16-element phased-array receiver for 76–84-GHz applications with built-in self-test (BIST) capabilities. The chip contains an in-phase/quadrature (I/Q) mixer suitable for automotive frequency-modulation continuous-wave radar applications, which is also used as part of the BIST system. The chip achieves 4-bit RF amplitude and phase control, an RF to IF gain of 30–35 dB at 77–84 GHz, I/Q balance of and at 76–84 GHz, and a system noise figure of 18 dB. The on-chip BIST covers the 76–84-GHz range and determines, without any calibration, the amplitude and phase of each channel, a normalized frequency response, and can measure the gain control using RF gain control. System-level considerations are discussed together with extensive results showing the effectiveness of the on-chip BIST as compared with standard -parameter measurements.
Autors: Kim, S.Y.;Inac, O.;Kim, C.-Y.;Shin, D.;Rebeiz, G.M.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Aug 2013, volume: 61, issue:8, pages: 3083 - 3098
Publisher: IEEE
 
» A 90–100-GHz 4 4 SiGe BiCMOS Polarimetric Transmit/Receive Phased Array With Simultaneous Receive-Beams Capabilities
Abstract:
Pub DtlThis paper presents a 4 4 transmit/receive (T/R) SiGe BiCMOS phased-array chip at 90–100 GHz with vertical and horizontal polarization capabilities, 3-bit gain control (9 dB), and 4-bit phase control. The 4 4 phased array fits into a grid, which is required at 94 GHz for wide scan-angle designs. The chip has simultaneous receive (Rx) beam capabilities (V and H) and this is accomplished using dual-nested 16:1 Wilkinson combiners/divider with high isolation. The phase shifter is based on a vector modulator with optimized design between circuit level and electromagnetic simulation and results in 1 dB and gain and phase error, respectively, at 85–110 GHz. The behavior of the vector modulator phase distortion versus input power level is investigated and measured, and design guidelines are given for proper operation in a transmit (Tx) chain. The V and H Rx paths result in a gain of 22 and 25 dB, respectively, a noise figure of 9–9.5 (max. gain), and 11 dB (min. gain) measured without the T/R switch, and an input of 31 to 26 dBm over the gain control range. The measured output is 5 dBm per channel, limited by the T/R- switch loss. Measurements show 0.6- and 0.75-dB variation between the 4 4 array elements in the Tx mode and Rx mode, respectively, and 40-dB coupling between the different channels on the chip. The chip consumes 1100 mA from a 2-V supply in both the Tx and Rx modes. The design can be scaled to 10 000 elements using polyimide redistribution layers on top of the chip and the application areas are in -band radars for landing systems.
Autors: Golcuk, F.;Kanar, T.;Rebeiz, G.M.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Aug 2013, volume: 61, issue:8, pages: 3099 - 3114
Publisher: IEEE
 
» A -Band RF Module Transmitter Including an RF Signal Generator for a Flexible Phased-Array System
Abstract:
Pub DtlThis paper presents a new concept of an active phased array antenna (APAA) system with RF modules, including an RF signal generator. The proposed APAA realizes multi-frequency and multi-modulation beam forming simultaneously by generating an RF signal independently in each module and sharing them among the antenna arrays. This configuration is effective in a distributed array radar system because the interconnect equipments of modules can be simplified by not transmitting an RF signal on the cables. Moreover, the proposed APAA can compensate the performance variation between output signals of RF modules. These features contribute a flexible and precise APAA operation. Key features of the proposed APAA are verified by measurements. A transmitter block of the RF module with three silicon–germanium integrated circuits is fabricated to validate the proposed functions and performances. The fabricated RF module generates the various modulated signals of 1 Gs/s and operates in -bands. It is achieved that the measurement accuracy of timing error, phase error, and amplitude error of RF output signals are 56 ps rms, 0.6° rms, and 0.6 dB rms, respectively.
Autors: Kawakami, K.;Nakamizo, H.;Tajima, K.;Taniguchi, E.;Akiyama, T.;Hieda, M.;Sakai, K.;Hayashi, R.;Nakayama, M.;Hirano, Y.;Chiba, I.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Aug 2013, volume: 61, issue:8, pages: 3052 - 3059
Publisher: IEEE
 
» A Bandwidth Improved Broadband Compact Lumped-Element Balun With Tail Inductor
Abstract:
A novel broadband compact lumped-element balun with a tail inductor is proposed in this letter. The employment of tail inductor improves amplitude and phase balances for better broadband performance. Furthermore, compared with baluns utilizing conventional micro-strip approaches or second-order lattice topology, this proposed topology offers significant circuit size reduction. Theoretical analysis of the optimized tail inductor value is presented to improve operation bandwidth. The concept is realized and validated by a 2.45 GHz balun with surface mounted devices (SMD). The measured results illustrate an amplitude balance less than 0.5 dB and a phase balance less than in a 36.7% bandwidth. The insertion loss is around 3.6 dB while the return loss of the unbalance port is better than 15 dB in the whole working frequency range. The core circuit occupies only 2 mm 2.5 mm limited by SMD size.
Autors: Ye, Y.;Li, L.-Y.;Gu, J.-Z.;Sun, X.-W.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Aug 2013, volume: 23, issue:8, pages: 415 - 417
Publisher: IEEE
 
» A Battery Energy Storage System Dual-Layer Control Strategy for Mitigating Wind Farm Fluctuations
Abstract:
Pub DtlThe intermittent power output of a wind farm is the main challenge behind increasing wind power penetration of power systems. This paper proposes a battery energy storage system (BESS) dual-layer control strategy—consisting of a fluctuation mitigation control layer and a power allocation control layer—to mitigate wind farm power output fluctuations. The fluctuation mitigation control layer calculates the power instructions for the BESS so that the combined wind farm and BESS power output meets fluctuation mitigation requirement (FMR). The layer implements a flexible first-order low-pass filter (FLF), updating the time constant of the FLF through use of a particle swarm optimization (PSO) algorithm. The power allocation control layer optimizes power instructions allocation among the battery energy storage units of the BESS. The layer's energy management of the BESS uses a mixed-integer quadratic programming (MIQP) model, which improves reliability. Moreover, the paper compares two types of charge/discharge switching constraints to reduce the number of charge/discharge cycles, which can prolong the operational lifetime of the BESS. Finally, the effectiveness of the proposed dual-layer control strategy is verified through case studies.
Autors: Jiang, Q.;Gong, Y.;Wang, H.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Aug 2013, volume: 28, issue:3, pages: 3263 - 3273
Publisher: IEEE
 
» A battery-less photo-detector enabled with simultaneous ferroelectric sensing and energy harnessing mechanism
Abstract:
A self-sustainable mechanism for simultaneously sensing and harnessing photon energy was proposed and implemented to create a battery-less and wire-less ultraviolet sensor made of ferroelectric lead lanthanum zirconate titanate thin film with in-plane polarization configuration. The mechanism involved accumulating and storing the photovoltaic charge, and transferring the stored charge via a piezoelectric switch to a radio frequency transmitter. The time-interval between the radio frequency pulses generated by the transmitter was inversely proportional to the photo-intensity. The sustainability of the operation was ascribed to the low leakage, high photovoltage, and linear current-voltage characteristics of ferroelectric sensing material instead of semiconductors.
Autors: Lai, Szu Cheng;Yao, Kui;Chen, Yi Fan;
Appeared in: Applied Physics Letters
Publication date: Aug 2013, volume: 103, issue:9, pages: 092903 - 092903-5
Publisher: IEEE
 
» A Behavioral Distance for Fuzzy-Transition Systems
Abstract:
In contrast with the existing approaches to exact bisimulation for fuzzy systems, we introduce a robust notion of behavioral distance to measure the behavioral similarity of nondeterministic fuzzy-transition systems which are a generalization of fuzzy automata. This behavioral distance provides a quantitative analogue of bisimilarity and is defined as the greatest fixed point of a suitable monotonic function. The behavioral distance has the important property that two systems are at zero distance if and only if they are bisimilar. Moreover, for any given threshold, we find that systems with behavioral distances bounded by the threshold are equivalent. In addition, we show that two system combinators—parallel composition and product—are nonexpansive with respect to our behavioral distance, which makes compositional verification possible. The theory developed here is applicable to the quantitative verification, approximate reduction, and reliability analysis of fuzzy-transition systems.
Autors: Cao, Y.;Sun, S.X.;Wang, H.;Chen, G.;
Appeared in: IEEE Transactions on Fuzzy Systems
Publication date: Aug 2013, volume: 21, issue:4, pages: 735 - 747
Publisher: IEEE
 
» A Binomial Model for Radiated Immunity Measurements
Abstract:
We propose a statistical analysis of immunity testing in EMC based on binomial distributions. This approach aims at extracting the immunity properties of a device from its probability of failure during a test. We show that under certain conditions, this approach can be applied to plane wave testing environments and reverberation chambers. This approach allows one to control the uncertainty of the immunity level estimation and to reduce the duration of a test by both reducing significantly the number of observations needed to reach a given uncertainty budget and giving an optimal number of power level tested. We show the benefits of such an approach for immunity testing and we present some experimental results.
Autors: Amador, E.;Krauthauser, H.G.;Besnier, P.;
Appeared in: IEEE Transactions on Electromagnetic Compatibility
Publication date: Aug 2013, volume: 55, issue:4, pages: 683 - 691
Publisher: IEEE
 
» A Bispectral Approach to Analyze Nonlinear Cochlear Active Mechanisms in Transient Evoked Otoacoustic Emissions
Abstract:
A new approach to study nonlinearity in cochlear active mechanisms, as evaluated in transient evoked otoacoustic emissions (TEOAEs), is presented. TEOAEs are signals generated in the cochlea by a mix of linear and nonlinear mechanisms. This new approach was designed to complement the traditional TEOAE analysis performed by currently available systems used in objective hearing screening and assessment. Nonlinearity of TEOAEs was studied by means of the bispectrum, which is able to find out quadratic frequency couplings (QFCs) that occur when a frequency is not only generated by an independent cochlear source, but it is the result of the interaction among a number of cochlear sources. To fit with the technical constraints of currently available TEOAE systems, the bispectrum was estimated by the third-order scaled polyperiodogram. The proposed method was characterized with synthesized TEOAEs as a function of the main TEOAE parameters and then used to analyze TEOAEs recorded in normal hearing adults and full-term neonates. Results revealed the presence of QFCs in both adult and neonatal TEOAEs, with peculiar patterns and significantly different frequency content in the two groups: adults had QFCs mainly around 2 kHz and neonates had QFCs mainly in the range 3.5–4 kHz.
Autors: Marchesi, S.;Tognola, G.;Paglialonga, A.;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Aug 2013, volume: 7, issue:4, pages: 401 - 413
Publisher: IEEE
 
» A Blumlein-type, nanosecond pulse generator with interchangeable transmission lines for bioelectrical applications
Abstract:
The design and realization of a nanosecond, high-voltage electric pulse generator for bioelectrical applications is reported in this paper. A Blumlein type architecture was adopted, with some modifications, and realized in a microstrip line configuration with meander-shaped conducting strips, and with ultra-fast, high voltage solid state switches. Three microstrip-lines have been realized in such a way that, being interchangeable within the structure, they allow to match different load impedances. A fiber optic-based system was also realized to separate the high voltage side of the system from the switch-control circuit. The system is suitable for applying high voltage nanosecond electric pulses, with variable pulse duration, amplitude, repetition rate and polarity, to liquid media with different electromagnetic characteristics, hosted in electroporation cuvettes with different gap dimensions.
Autors: Romeo, S.;D'Avino, C.;Zeni, O.;Zeni, L.;
Appeared in: IEEE Transactions on Dielectrics and Electrical Insulation
Publication date: Aug 2013, volume: 20, issue:4
Publisher: IEEE
 
» A brightness exceeding simulated Langmuir limit
Abstract:
When an excitation of the first lens determines a beam is parallel beam, a brightness that is 100 times higher than Langmuir limit is measured experimentally, where Langmuir limits are estimated using a simulated axial cathode current density which is simulated based on a measured emission current. The measured brightness is comparable to Langmuir limit, when the lens excitation is such that an image position is slightly shorter than a lens position. Previously measured values of brightness for cathode apical radii of curvature 20, 60, 120, 240, and 480 μm were 8.7, 5.3, 3.3, 2.4, and 3.9 times higher than their corresponding Langmuir limits, respectively, in this experiment, the lens excitation was such that the lens and the image positions were 180 mm and 400 mm, respectively. From these measured brightness for three different lens excitation conditions, it is concluded that the brightness depends on the first lens excitation. For the electron gun operated in a space charge limited condition, some of the electrons emitted from the cathode are returned to the cathode without having crossed a virtual cathode. Therefore, method that assumes a Langmuir limit defining method using a Maxwellian distribution of electron velocities may need to be revised. For the condition in which the values of the exceeding the Langmuir limit are measured, the simulated trajectories of electrons that are emitted from the cathode do not cross the optical axis at the crossover, thus the law of sines may not be valid for high brightness electron beam systems.
Autors: Nakasuji, Mamoru;
Appeared in: Review of Scientific Instruments
Publication date: Aug 2013, volume: 84, issue:8, pages: 083703 - 083703-8
Publisher: IEEE
 
» A Broadband Model of the Characteristic Currents for Rectangular Plates
Abstract:
This paper presents an approximate model of the characteristic currents for rectangular plates. This model provides a broadband description of the characteristic current distributions, which could be used for the far-field or near-field cases. For narrow rectangular plates, a modified cosine function and sine function are adapted for the odd and even modes, respectively. As the narrow case is fundamentally a 1-D problem, the presented solution could be scaled for arbitrary combinations of plate length and operating frequency. For wide rectangular plates, each characteristic current is decomposed into four parts along the plate edges, which decay exponentially toward the opposite edges. Variance of the characteristic currents with plate dimension is observed and briefly discussed. The frequency-dependent but axis-independent mode coefficients are utilized and numerically evaluated to verify the proposed model. The modal solutions of two rectangular plates that are illuminated by a normally incident planar wave are given and compared with the full-wave solutions. The modal solutions composed of the lowest four terms provide an explicit description of the surface currents with reasonable accuracy. Axis dependence of the mode coefficients is briefly discussed, and the first-order expression contributes an improved accuracy when the mode number is larger than 1.
Autors: Wu, Q.;Su, D.;
Appeared in: IEEE Transactions on Electromagnetic Compatibility
Publication date: Aug 2013, volume: 55, issue:4, pages: 725 - 732
Publisher: IEEE
 
» A Buck Resonant Voltage Divider With Bidirectional Operation Considered
Abstract:
In this paper, a buck resonant voltage divider (RVD) (BRVD) with bidirectional operation considered is presented, which can be used as the first stage of the bus converter. The proposed BRVD under open-loop control can obtain about half of the output voltage created from the existing RVD. Above all, the used switches have zero-current switching at turn off or zero-voltage switching at turn-on. Moreover, the bidirectional operation of the proposed topology is also taken into consideration. The detailed illustration of the proposed topology is provided along with some experimental results to verify their effectiveness.
Autors: Hwu, K.I.;Yau, Y.T.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Aug 2013, volume: 49, issue:4, pages: 1566 - 1576
Publisher: IEEE
 
» A Bulk-Micromachined Fully Differential MEMS Accelerometer With Split Interdigitated Fingers
Abstract:
This paper proposes a novel bulk-micromachined MEMS accelerometer employing split interdigitated sense fingers that provide a fully differential signal interface, where the accelerometer can be fabricated by a modified silicon-on-glass process using a silicon-on-insulator (SOI) wafer. The accelerometer combines the feasibility of fabricating large mass and high aspect ratio structures using bulk-micromachining together with the highly sensitive split interdigitated sense finger triplets that are connected with multilayer metal interconnects on an SOI-glass bonded wafer. The fabricated accelerometer is packaged for system level tests with a fourth-order readout circuitry to evaluate its performance. The measurement results show that the accelerometer achieves a bias instability of 50 and a velocity random walk of 11.5 . The accelerometer operates in a range of with a nonlinearity of 1140 ppm
Autors: Aydin, O.;Akin, T.;
Appeared in: IEEE Sensors Journal
Publication date: Aug 2013, volume: 13, issue:8, pages: 2914 - 2921
Publisher: IEEE
 
» A Chance-Constrained Unit Commitment With an Security Criterion and Significant Wind Generation
Abstract:
This paper presents a new approach for the joint energy and reserves scheduling and unit commitment with reliability constraints for the day-ahead market. The proposed method includes a novel criterion where demand must be met with a specified probability under any simultaneous loss of generating units. A chance-constrained method is proposed with an -quantile measure to determine the confidence level to meet the demand under simultaneous contingencies. The chance-constrained optimization problem is recast as a mixed integer linear programming optimization problem. Wind and demand uncertainty are included into the model. The methodology proposed is illustrated with several case studies where the effect of increasing wind power penetration is analyzed showing the performance of our model.
Autors: Pozo, D.;Contreras, J.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Aug 2013, volume: 28, issue:3, pages: 2842 - 2851
Publisher: IEEE
 
» A circuit analysis of an in situ tunable radio-frequency quantum point contact
Abstract:
A detailed analysis of the tunability of a radio-frequency quantum point contact setup using a C - LCR circuit is presented. We calculate how the series capacitance influences resonance frequency and charge-detector resistance for which matching is achieved as well as the voltage and power delivered to the load. Furthermore, we compute the noise contributions in the system and compare our findings with measurements taken with an etched quantum point contact. While our considerations mostly focus on our specific choice of matching circuit, the discussion of the influence of source-to-load power transfer on the signal-to-noise ratio is valid generally.
Autors: Muller, T.;Choi, T.;Hellmuller, S.;Ensslin, K.;Ihn, T.;Schon, S.;
Appeared in: Review of Scientific Instruments
Publication date: Aug 2013, volume: 84, issue:8, pages: 083902 - 083902-9
Publisher: IEEE
 
» A CMOS Highly Linear Hybrid Current/Voltage Controlled Oscillator for Wideband Polar Modulation
Abstract:
A highly linear oscillator is presented for wideband polar modulation. It has both a varactor voltage tuning input for frequency locking and temperature compensation of phase locked loop (PLL) as well as an inductive current tuning input for linear phase modulation of PLL. Implemented in 65 nm CMOS technology, it achieved a frequency tuning gain variation of less than 2% over more than 32 MHz frequency range meeting the WCDMA polar modulation requirement. At 3.8 GHz and 3 MHz offset, its phase noise is 136.5 dBc/Hz with current consumption of 18 mA from 2.1 V supply.
Autors: Tang, Y.;Hu, J.;Park, J.;Choi, J.;Leung, L.;Narathong, C.;Sahota, K.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Aug 2013, volume: 60, issue:8, pages: 1991 - 2000
Publisher: IEEE
 
» A CMOS-MEMS Resonator Integrated System for Oscillator Application
Abstract:
This paper focuses on the design and development of a CMOS-MEMS resonator integrated with an on-chip amplifier with emphasis on its single-chip frequency reference oscillator implementation. A flexural-mode ring resonator with a desired mode shape featuring an inherent fully-differential mode of mechanical operation is designed using both analytical and finite element models. Two such resonators in low- and high-frequency domains, centered at 1.39 and 9.34 MHz respectively, are individually modeled using first principals, equations, and simulation tools to evaluate and improve device performance. In this paper, the device is also shown to offer a potential benefit of capacitive feedthrough cancelation up to 30 dB attributed to differential signaling scheme. Subsequently, both rapidly prototyped devices integrated with their on-chip transimpedance amplifiers are demonstrated using a commercially available TSMC 0.35- CMOS technology. A low-frequency resonator integrated with its on-chip amplifier exhibited decent overall performance capabilities in terms of much higher transmission spectra (closer to 0 dB), greater feedthrough suppression, higher signal-to-feedthrough ratio (35 dB), and exact phase shift (0 ) at resonance frequency, therefore being a potential candidate for a single-chip oscillator system.
Autors: Pachkawade, V.;Li, M.-H.;Li, C.-S.;Li, S.-S.;
Appeared in: IEEE Sensors Journal
Publication date: Aug 2013, volume: 13, issue:8, pages: 2882 - 2889
Publisher: IEEE
 
» A Compact Dual-Polarized Double -Shaped Patch Antenna With High Isolation
Abstract:
A compact dual-polarized double E-shaped patch antenna with high isolation for pico base station applications is presented in this communication. The proposed antenna employs a stacked configuration composed of two layers of substrate. Two modified E-shaped patches are printed orthogonally on both sides of the upper substrate. Two probes are used to excite the E-shaped patches, and each probe is connected to one patch separately. A circular patch is printed on the lower substrate to broaden the impedance bandwidth. Both simulated and measured results show that the proposed antenna has a port isolation higher than 30 dB over the frequency band of 2.5 GHz - 2.7 GHz, while the return loss is less than - 15 dB within the band. Moreover, stable radiation pattern with a peak gain of 6.8 dBi - 7.4 dBi is obtained within the band.
Autors: Yanshan Gou;Shiwen Yang;Quanjiang Zhu;Zaiping Nie;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Aug 2013, volume: 61, issue:8, pages: 4349 - 4353
Publisher: IEEE
 
» A Compact Notched Band UWB Slot Antenna With Sharp Selectivity and Controllable Bandwidth
Abstract:
A compact ultra-wideband (UWB) slot antenna with band-notched characteristics is proposed. A stepped slot is adopted as a radiator to realize UWB impedance matching and reduce the antenna size. By slitting an open-ended quarter-wavelength split slot on the back of the feed and a short-ended half-wavelength split-ring slot near the stepped slot, a second-order notched band of 5.15–5.85 GHz is achieved. Compared with the traditional band-notched antenna, the selectivity of the notched band is greatly improved and size of the antenna is reduced at the same time. The volume of the antenna is only . Besides, the bandwidth can be easily controlled by adjusting the lengths of the two slots respectively. Good agreement is achieved between simulated and measured results, which show that the proposed antenna has nice impedance matching and radiation pattern characteristics.
Autors: Chu, Q.-X.;Mao, C.-X.;Zhu, H.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Aug 2013, volume: 61, issue:8, pages: 3961 - 3966
Publisher: IEEE
 
» A Comprehensive Investigation of Wireless LAN for IEC 61850–Based Smart Distribution Substation Applications
Abstract:
Today's power grid is facing many challenges due to increasing load growth, aging of existing power infrastructures, high penetration of renewable, and lack of fast monitoring and control. Utilizing recent developments in Information and Communication Technologies (ICT) at the power-distribution level, various smart-grid applications can be realized to achieve reliable, efficient, and green power. Interoperable exchange of information is already standardized in the globally accepted smart-grid standard, IEC 61850, over the local area networks (LANs). Due to low installation cost, sufficient data rates, and ease of deployment, the industrial wireless LAN technologies are gaining interest among power utilities, especially for less critical smart distribution network applications. Extensive work is carried out to examine the wireless LAN (WLAN) technology within a power distribution substation. The first phase of the work is initiated with the radio noise interference measurements at 27.6- and 13.8-kV distribution substations, including circuit breaker switching operations. For a detailed investigation, the hardware prototypes of WLAN-enabled IEC 61850 devices are developed using industrial embedded systems, and the performance of smart distribution substation monitoring, control, and protection applications is analyzed for various scenarios using a round trip-time of IEC 61850 application messages. Finally, to examine the real-world field performance, the developed prototype devices are installed in the switchyard and control room of 27.6 power distribution substation, and testing results of various applications are discussed.
Autors: Parikh, P.P.;Sidhu, T.S.;Shami, A.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Aug 2013, volume: 9, issue:3, pages: 1466 - 1476
Publisher: IEEE
 
» A Comprehensive LVRT Control Strategy for DFIG Wind Turbines With Enhanced Reactive Power Support
Abstract:
Pub DtlThe paper presents a new control strategy to enhance the ability of reactive power support of a doubly fed induction generator (DFIG) based wind turbine during serious voltage dips. The proposed strategy is an advanced low voltage ride through (LVRT) control scheme, with which a part of the captured wind energy during grid faults is stored temporarily in the rotor's inertia energy and the remaining energy is available to the grid while the DC-link voltage and rotor current are kept below the dangerous levels. After grid fault clearance, the control strategy ensures smooth release of the rotor's excessive inertia energy into the grid. Based on these designs, the DFIG's reactive power capacity on the stator and the grid side converter is handled carefully to satisfy the new grid code requirements strictly. Simulation studies are presented and discussed.
Autors: Xie, D.;Xu, Z.;Yang, L.;Ostergaard, J.;Xue, Y.;Wong, K.P.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Aug 2013, volume: 28, issue:3, pages: 3302 - 3310
Publisher: IEEE
 
» A consistent approach to estimate the breakdown voltage of high voltage electrodes under positive switching impulses
Abstract:
The main propose of this paper is to present a physical model of long air gap electrical discharges under positive switching impulses. The development and progression of discharges in long air gaps are attributable to two intertwined physical phenomena, namely, the leader channel and the streamer zone. Experimental studies have been used to develop empirical and physical models capable to represent the streamer zone and the leader channel. The empirical ones have led to improvements in the electrical design of high voltage apparatus and insulation distances, but they cannot take into account factors associated with fundamental physics and/or the behavior of materials. The physical models have been used to describe and understand the discharge phenomena of laboratory and lightning discharges. However, because of the complex simulations necessary to reproduce real cases, they are not in widespread use in the engineering of practical applications. Hence, the aim of the work presented here is to develop a model based on physics of the discharge capable to validate and complement the existing engineering models. The model presented here proposes a new geometrical approximation for the representation of the streamer and the calculation of the accumulated electrical charge. The model considers a variable streamer region that changes with the temporal and spatial variations of the electric field. The leader channel is modeled using the non local thermo-equilibrium equations. Furthermore, statistical delays before the inception of the first corona, and random distributions to represent the tortuous nature of the path taken by the leader channel were included based on the behavior observed in experimental tests, with the intention of ensuring the discharge behaved in a realistic manner. For comparison purposes, two different gap configurations were simulated. A reasonable agreement was found between the physical model and the experimental test results.
Autors: Arevalo, L.;Wu, D.;Jacobson, B.;
Appeared in: Journal of Applied Physics
Publication date: Aug 2013, volume: 114, issue:8, pages: 083301 - 083301-8
Publisher: IEEE
 
» A Continuous Biomedical Signal Acquisition System Based on Compressed Sensing in Body Sensor Networks
Abstract:
The emerging compressed sensing (CS) holds considerable promise for continuously acquiring biomedical signals in body sensor networks (BSNs), which enables nodes to employ a much lower sampling rate than Nyquist while still able to accurately reconstruct signals. CS-based BSNs are expected to significantly enhance the quality of healthcare and improve the ability of prevention, early diagnosis, and treatment of chronic diseases. However, existing BSNs are still unable to support long-term monitoring in healthcare, as well as providing an energy-efficient low communication burden and inexpensive scheme. Capitalizing on the sparsity of biomedical signals in transfer domains, this paper develops a continuous biomedical signal acquisition system, which explores a sparsification model to find the sparse representation of biomedical signals. The sparsified measurements of signals are wirelessly transmitted to a fusion center through BSNs. Meanwhile, a weighted group sparse reconstruction algorithm is proposed to accurately reconstruct the signals at the fusion center. Simulation results show that, on random sampling over BSN, the proposed group sparse algorithm shows good efficiency, strong stability, and robustness.
Autors: Li, S.;Xu, L;Wang, X.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Aug 2013, volume: 9, issue:3, pages: 1764 - 1771
Publisher: IEEE
 
» A Cost-Effective Preamble-Assisted Engine With Skew Calibrator for Frequency-Dependent I/Q Imbalance in 4 4 MIMO-OFDM Modem
Abstract:
Variations in I/Q gains, phases, and filters of the RF frontend, namely frequency-dependent I/Q imbalance (FDI), are an important factor in OFDM-based wireless access. To enable the proper function of a 4 4 MIMO-OFDM receiver this work proposes a low-complexity preamble-assisted solution using only one complex divider and one complex multiplier to handle significant FDI distortions. An all-digital multiphase and multi-rate clock generator (MPRCG) was built to support fast dynamic frequency scaling for FDI estimation and compensation and for efficient implementation. Based on the proposed MPRCG, a skew calibration was also realized to tune I/Q timing coherently via multiphase A/D clocking. Performance evaluation showed that the proposed approach incurs an SNR loss of 1.5 dB to maintain a packet-error rate of less than 10% under a 1 dB gain error, 15 phase error and worse filter mismatch. Thus, this solution not only provides adequate performance, but also makes FDI estimation and compensation more cost-effective.
Autors: Lai, W.-C.;Liao, Y.-T.;Hsu, T.-Y.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Aug 2013, volume: 60, issue:8, pages: 2199 - 2212
Publisher: IEEE
 
» A Coupling Matrix-Based Design of Triple-Band Matching Network
Abstract:
This letter proposes an analysis for synthesizing concurrent triple-band matching networks based on a modified coupling matrix theorem. Detailed design procedures are outlined for triple-band matching networks with illustrative design examples; a feasible simulation of hairpin resonator-based design reproduces the analytic prediction response. Excellent agreement between the theory and the EM simulation is obtained to validate the theory. Furthermore, compared to other matching networks, specific triple bands can be designed, and the selectivity and rejection capability in undesired bands are both excellent.
Autors: Lee, C.-S.;Yang, C.-L.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Aug 2013, volume: 23, issue:8, pages: 391 - 393
Publisher: IEEE
 
» A Cross-Layer Judgment Scheme for Solving Retransmission Problem in IEEE 802.15.4-Based Wireless Body Sensor Networks
Abstract:
In IEEE 802.15.4 wireless personal area networks (WPANs), reliable data transmission is an important issue in areas such as body information for medical treatments. Some handshaking mechanisms in literatures are studied and proposed to guarantee successful data frame transmission. One is to adopt ACK frame, which is replied by the receiver back to the sender when the data frame is correctly received. This is a popular mechanism. However, there are many different reasons, such as the fading channel, data frame collision, and hidden terminal problem, by which data frames cannot be correctly received on the receiver. Therefore, a sender should have different data retransmission policies and procedures for data frame retransmission. Neglecting these measures of failed transmission, the data frame retransmission may fail again, and the transmission efficiency will be degraded. In this paper, we propose a cross-layer judgment scheme (CL-JS) to solve the retransmission problem. It does not require the extra control overhead, but it can correctly judge the reasons of failed transmission from overlapped signals. Thus, the sender can adaptively adjust system parameters to handle the different retransmission procedures. Simulation results validated by mathematical analysis show that the proposed scheme significantly improves the goodput with the reduction in power consumption.
Autors: Tseng, H.-W.;Chuang, Y.-R.;
Appeared in: IEEE Sensors Journal
Publication date: Aug 2013, volume: 13, issue:8, pages: 3124 - 3135
Publisher: IEEE
 
» A Cross-Layer QoS-Aware Communication Framework in Cognitive Radio Sensor Networks for Smart Grid Applications
Abstract:
Electromagnetic interference, equipment noise, multi-path effects and obstructions in harsh smart grid environments make the quality-of-service (QoS) communication a challenging task for WSN-based smart grid applications. To address these challenges, a cognitive communication based cross-layer framework has been proposed. The proposed framework exploits the emerging cognitive radio technology to mitigate the noisy and congested spectrum bands, yielding reliable and high capacity links for wireless communication in smart grids. To meet the QoS requirements of diverse smart grid applications, it differentiates the traffic flows into different priority classes according to their QoS needs and maintains three dimensional service queues attributing delay, bandwidth and reliability of data. The problem is formulated as a Lyapunov drift optimization with the objective of maximizing the weighted service of the traffic flows belonging to different classes. A suboptimal distributed control algorithm (DCA) is presented to efficiently support QoS through channel control, flow control, scheduling and routing decisions. In particular, the contributions of this paper are three folds; employing dynamic spectrum access to mitigate with the channel impairments, defining multi-attribute priority classes and designing a distributed control algorithm for data delivery that maximizes the network utility under QoS constraints. Performance evaluations in ns-2 reveal that the proposed framework achieves required QoS communication in smart grid.
Autors: Shah, G.A.;Gungor, V.C.;Akan, O.B.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Aug 2013, volume: 9, issue:3, pages: 1477 - 1485
Publisher: IEEE
 
» A Cross-Layer Technology-Based Study of How Memory Errors Impact System Resilience
Abstract:
Highly scaled technologies at and beyond the 22-nm node exhibit increased sensitivity to various scaling-related problems that conspire to reduce the overall reliability of integrated circuits and systems. In prior technology nodes, the assumption was that manufacturing technology was responsible for ensuring device reliability. This basic assumption is no longer tenable. Trying to contain reliability problems purely at the technology level would cause prohibitive increases in power consumption. Thus, a cross-layer approach is required, which spreads the burden of ensuring resilience across multiple levels of the design hierarchy. This article illustrates a methodology for dealing with scaling-related problems via two case studies that link models of low-level technology-related problems to system behavior.
Autors: Kleeberger, Veit B.;Gimmler-Dumont, Christina;Weis, Christian;Herkersdorf, Andreas;Mueller-Gritschneder, Daniel;Nassif, Sani R.;Schlichtmann, Ulf;Wehn, Norbert;
Appeared in: IEEE Micro
Publication date: Aug 2013, volume: 33, issue:4, pages: 46 - 55
Publisher: IEEE
 
» A CSRR Loaded MIMO Antenna System for ISM Band Operation
Abstract:
A 2 2 (four-element) multiple-input multiple-output (MIMO) patch antenna system is designed and fabricated for a 2.45-GHz ISM band operation. It uses complementary split-ring resonator (CSRR) loading on its ground plane for antenna miniaturization. This reduces the single-element antenna size by 76%. The total board size of the proposed MIMO antenna system, including the GND plane is 100 50 0.8 mm , while the single-patch antenna element has a size of 14 18 mm . The antenna is fabricated and tested. Measured results are in good agreement with simulations. A minimum measured isolation of 10 dB is obtained given the close interelement spacing of . The maximum measured gain for a single operating element is 0.8 dBi.
Autors: Sharawi, M.S.;Khan, M.U.;Numan, A.B.;Aloi, D.N.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Aug 2013, volume: 61, issue:8, pages: 4265 - 4274
Publisher: IEEE
 
» A custom-made semi-conducting powder for high voltage field grading applications
Abstract:
In this work, a powder tailored to fulfill the required conditions for field grading of HV applications was designed using a high-energy ball milling and annealing process. Excellent results in line with requirements were found, and show that this powder can be custom-made for the intended present and future applications. The different powders introduced here are based on aluminum (Al) and boron nitride (BN) powders interacting to produce aluminum nitride (AlN) and semi-conductive aluminum boride. Conductivity characteristics similar to and/or at variance with those of SiC were observed.
Autors: Vanga-Bouanga, C.;Frechette, M.F.;David, E.;
Appeared in: IEEE Transactions on Dielectrics and Electrical Insulation
Publication date: Aug 2013, volume: 20, issue:4
Publisher: IEEE
 
» A deep optical cavity trap for atoms and molecules with rapid frequency and intensity modulation
Abstract:
We describe a deep far-off resonance trap for metastable argon atoms utilizing a medium finesse cavity and a high input power (30 W) to produce trap depths of up to 11 mK. The depth can be rapidly modulated allowing efficient loading of the trap, characterization of trapped atom temperature, and reduction of intensity noise. We measure the change in radius of curvature of the mirrors due to heating by the high circulating intensity and show that trapping is not adversely effected by this for all input powers.
Autors: Edmunds, P.D.;Barker, P.F.;
Appeared in: Review of Scientific Instruments
Publication date: Aug 2013, volume: 84, issue:8, pages: 083101 - 083101-5
Publisher: IEEE
 
» A Defocused Rotman Lens With Reduced Conjugate Port Coupling
Abstract:
The Roman lens is suitable as an antenna beam-forming network, but performance suffers from high coupling between symmetrically opposed (or conjugate) ports. A practical technique to reduce this coupling is presented and experimentally validated. It is proposed that the curvature of the lens contour is modified to be sub-optimal in terms of phase errors, but is done in such a way that the defocusing spreads the power and leads to reduced conjugate port coupling. The phase errors thus generated are shown to be of the same order as those found in conventional Rotman lenses. This new, defocused lens is compared to the conventional lens showing improved coupling performance without degradation of the phase performance. A lens is implemented in waveguide and measured results agree well with simulations.
Autors: Ibbotson, A.;de Villiers, D.I.L.;Palmer, K.D.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Aug 2013, volume: 23, issue:8, pages: 394 - 396
Publisher: IEEE
 
» A Design and Assessment of a Direction Finding Proximity Fuze Sensor
Abstract:
This paper presents the implementation and assessment of a direction finding proximity fuze sensor for anti-aircrafts or anti-air missiles. A higher rejection of clutter signals is achieved by employing a binary phase shift keying modulation using Legendre sequence. The direction finding is implemented by comparing received powers from six receiving antennas equally spaced by an angle of 60 around a cylindrical surface.
Autors: Choi, J.-H.;Jung, M.-S.;Yeom, K.-W.;
Appeared in: IEEE Sensors Journal
Publication date: Aug 2013, volume: 13, issue:8, pages: 3079 - 3089
Publisher: IEEE
 
» A Design Methodology for Power Efficiency Optimization of High-Speed Equalized-Electrical I/O Architectures
Abstract:
Both power efficiency and per-channel data rates of high-speed input/output (I/O) links must be improved in order to support future inter-chip bandwidth demand. In order to scale data rates over band-limited channels, various types of equalization circuitry are used to compensate for frequency-dependent loss. However, this additional complexity introduces power and area costs, requiring selection of an appropriate I/O equalization architecture in order to comply with system power budgets. This paper presents a design flow for power optimization of high-speed electrical links at a given data rate, channel type, and process technology node, which couples statistical link analysis techniques with circuit power estimates based on normalized transistor parameters extracted with a constant current density methodology. The design framework selects the optimum equalization architecture, circuit logic style (CMOS versus current-mode logic), and transmit output swing for minimum I/O power. Analysis shows that low loss channel characteristics and minimal circuit complexity, together with scaling of transmitter output swing allows excellent power efficiency at high data rates.
Autors: Palaniappan, A.;Palermo, S.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Aug 2013, volume: 21, issue:8, pages: 1421 - 1431
Publisher: IEEE
 
» A Digital Phase-Locked Loop With Calibrated Coarse and Stochastic Fine TDC
Abstract:
A coarse–fine time-to-digital converter (TDC) is presented with a calibrated coarse stage followed by a stochastic fine stage. On power-up, a calibration algorithm based on a code density test is used to minimize nonlinearities in the coarse TDC. By using a balanced mean method, the number of registers required for the calibration algorithm is reduced by 30%. Based upon the coarse TDC output, the appropriate clock signals are multiplexed into the stochastic fine TDC. The TDC is incorporated into a 1.99–2.5-GHz digital phase-locked loop (DPLL) in 0.13- m CMOS. The DPLL consumes a total of 15.2 mW of which 4.4 mW are consumed in the TDC. Measurements show an in-band phase noise of 107 dBc/Hz which is equivalent to 4-ps TDC resolution, approximately an order of magnitude better than an inverter delay in this process technology. The integrated random jitter is 213 fs rms for a 2-GHz output carrier frequency with 700-kHz loop bandwidth. The calibration reduces worst-case spurs by 16 dB.
Autors: Samarah, A.;Carusone, A.C.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Aug 2013, volume: 48, issue:8, pages: 1829 - 1841
Publisher: IEEE
 
» A digitizer based compact digital spectrometer for ion beam analysis using field programmable gate arrays and various energy algorithms
Abstract:
We report on the implementation of a compact multi-detector fully digital spectrometer and data acquisition system at a nuclear microprobe for ion beam analysis and imaging. The spectrometer design allows for system scalability with no restriction on the number of detectors. It consists of four-channel high-speed digitizer modules for detector signal acquisition and one low-speed digital-to-analog converter (DAC) module with two DAC channels and additional general purpose inputs/outputs to control ion beam scanning and data acquisition. Each digitizer module of the spectrometer provides its own Field Programmable Gate Array (FPGA) as digital signal processing unit to analyze detector signals as well as to synchronize the ion beam position in hard real-time. With the customized FPGA designs for all modules, all calculation intensive tasks are executed inside the modules, which reduces significantly the data stream to and CPU load on the control computer. To achieve an optimal energy resolution for all detector/preamplifier pulse shape characteristics, a user-definable infinite impulse response filter with high throughput for energy determination was implemented. The new spectrometer has an online data analysis feature, a compact size, and is able to process any type of detector signals such as particle induced x-ray emission, Rutherford backscattering spectrometry, or scanning transmission ion microscopy.
Autors: Jager, Markus;Reinert, Tilo;
Appeared in: Review of Scientific Instruments
Publication date: Aug 2013, volume: 84, issue:8, pages: 085105 - 085105-10
Publisher: IEEE
 
» A direct digital synthesis chirped pulse Fourier transform microwave spectrometer
Abstract:
Chirped pulse Fourier transform microwave (CP-FTMW) spectrometers have become the instrument of choice for acquiring rotational spectra, due to their high sensitivity, fast acquisition rate, and large bandwidth. Here we present the design and capabilities of a recently constructed CP-FTMW spectrometer using direct digital synthesis (DDS) as a new method for chirped pulse generation, through both a suite of extensive microwave characterizations and deep averaging of the 10-14 GHz spectrum of jet-cooled acetone. The use of DDS is more suited for in situ applications of CP-FTMW spectroscopy, as it reduces the size, weight, and power consumption of the chirp generation segment of the spectrometer all by more than an order of magnitude, while matching the performance of traditional designs. The performance of the instrument was further improved by the use of a high speed digitizer with dedicated signal averaging electronics, which facilitates a data acquisition rate of 2.1 kHz.
Autors: Finneran, Ian A.;Holland, Daniel B.;Carroll, P.Brandon;Blake, Geoffrey A.;
Appeared in: Review of Scientific Instruments
Publication date: Aug 2013, volume: 84, issue:8, pages: 083104 - 083104-6
Publisher: IEEE
 
» A Discussion of New Requirements for Measurement of Harmonic Distortion in Modern Power Supply Systems
Abstract:
This paper discusses some of the new requirements in the measurement of harmonic distortion in modern power supply systems: the measurement of the distortion over the harmonic range and the time–frequency analysis of harmonic distortion, and presents the basic performance of a new advanced digital measurement instrument that, in addition to classical harmonic distortion, provides an extended analysis of the distortion in the time–frequency domain.
Autors: Barros, J.;Diego, R.I.;de Apraiz, M.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Aug 2013, volume: 62, issue:8, pages: 2129 - 2139
Publisher: IEEE
 
» A Distributed Fault Detection Filtering Approach for a Class of Interconnected Continuous-Time Nonlinear Systems
Abstract:
This paper develops a filtering approach for distributed fault detection of a class of interconnected continuous-time nonlinear systems with modeling uncertainties, disturbances and measurement noise. A distributed fault detection scheme and the corresponding adaptive thresholds are designed based on filtering certain signals so that the effect of the measurement noise and of the disturbances is attenuated, allowing for the design of less conservative thresholds. A key novelty of the proposed work is that a general class of filters can be embedded into the design of the residual and threshold signals in a way that takes advantage of the filtering noise suppression properties. The analysis of the proposed distributed fault detection scheme shows that the derived thresholds guarantee that there are no false alarms and characterizes quantitatively the class of detectable faults. Further rigorous detectability analysis provides results regarding the magnitude of the detectable faults, an upper bound on the detection time and the relation of the detection time with respect to the order and pole locations of the filters used. Simulation results illustrate the proposed distributed fault filtering approach.
Autors: Keliris, C.;Polycarpou, M.M.;Parisini, T.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Aug 2013, volume: 58, issue:8, pages: 2032 - 2047
Publisher: IEEE
 
» A Dual Probe STM Imaging System and a Low Noise Switched-Capacitor Transimpedance Amplifier
Abstract:
This article reports a dual probe STM imaging system that doubles traditional STM frame rate and is capable of being scaled up to perform highly parallel STM imaging. A CMOS MEMS probe array is controlled by two off-chip servo loops to generate two STM images simultaneously. A CMOS switched-capacitor transimpedance amplifier (SCTIA) is integrated with the CMOS MEMS probe to locally sense tunneling current and facilitate future extension to much larger arrays. The SCTIA is sampled at the frequency of 166 kHz to produce an ultra-high transimpedance gain of 88 with a tunnel current bandwidth of 40 kHz. Correlated double sampling is utilized to achieve an extremely low input referred noise current floor of just 25 . This novel SCTIA is designed and fabricated in a 0.35 BiCMOS process, with its core SCTIA occupying an area of just 0.02 .
Autors: Tang, Y.;Zhang, Y.;Fedder, G.K.;Carley, L.R.;
Appeared in: IEEE Sensors Journal
Publication date: Aug 2013, volume: 13, issue:8, pages: 2984 - 2992
Publisher: IEEE
 
» A Fast Re-Route Method
Abstract:
We present a method to find an alternate path, after a link failure, from a source node to a destination node, before the Interior Gateway Protocol (e.g., OSPF or IS-IS) has had a chance to reconverge in response to the failure. The target application is a small (up to tens of nodes) regional access subnetwork of a service provider's network, which is a typical access scale encountered in practice. We illustrate the method and prove that it will find a path if one exists.
Autors: Rosenberg, Eric;Uttaro, James;
Appeared in: IEEE Communications Letters
Publication date: Aug 2013, volume: 17, issue:8, pages: 1656 - 1659
Publisher: IEEE
 
» A Frequency-Constrained Stochastic Economic Dispatch Model
Abstract:
Pub DtlIn this paper, we formulate the economic dispatch problem as a two-stage stochastic convex program for operational decision making under uncertainty. Post-contingency minimum frequency constraints are formulated as convex sets using a simplified model of frequency dynamics. The L-shaped method is used to decompose the large stochastic program into smaller sub-problems. Large-scale system examples are provided to demonstrate the computational efficiency of the proposed model formulation. Numerical results show the value of the proposed model and indicate that the proposed model is especially useful under a higher level of wind penetration.
Autors: Lee, Y.-Y.;Baldick, R.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Aug 2013, volume: 28, issue:3, pages: 2301 - 2312
Publisher: IEEE
 
» A Functional Sensor Placement Optimization Method for Power Systems Health Monitoring
Abstract:
Health monitoring of complex power systems requires multiple sensors to extract vital information from the sensed environment and internal conditions of the systems and their elements. A critical decision, particularly in the context of complex systems, is the number and locations of the sensors given a set of technical and nontechnical constraints. This paper provides a Bayesian belief network (BBN) based sensor placement optimization methodology for power systems health monitoring. The approach uses the functional topology of the system, physical models of sensor information, and Bayesian inference techniques along with the constraints. Information metric functions are used for optimized sensor placement based on the value of information that each possible “sensor placement scenario” provides. The proposed methodology is designed to answer important questions such as how to infer the health of a system based on limited number of monitoring points at certain subsystems (upward propagation), how to infer the health of a subsystem based on knowledge of the health of the main system (downward propagation), and how to infer the health of a subsystem based on knowledge of the health of other subsystems (distributed propagation). Dynamic BBN is used as the engine of projecting the health of the system.
Autors: Pourali, M.;Mosleh, A.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Aug 2013, volume: 49, issue:4, pages: 1711 - 1719
Publisher: IEEE
 
» A Fuzzy Logic-Based System for Indoor Localization Using WiFi in Ambient Intelligent Environments
Abstract:
Ambient intelligence is a new information paradigm, where people are empowered through a digital environment that is “aware” of their presence and context and is sensitive, adaptive, and responsive to their needs. Hence, one of the important requirements for ambient intelligent environments (AIEs) is the ability to localize the whereabouts of the user in the AIE to address her/his needs. In order to protect user privacy, the use of cameras is not desirable in AIEs, and hence, there is a need to rely on nonintrusive sensors. There are various localization means that are available for outdoor spaces such as those which rely on satellite signals triangulation. However, these outdoor localization means cannot be used in indoor environments. The majority of nonintrusive and noncamera-based indoor localization systems require the installation of extra hardware such as ultrasound emitters/antennas, radio-frequency identification (RFID) antennas, etc. In this paper, we propose a novel indoor localization system that is based on WiFi signals which are free to receive, and they are available in abundance in the majority of domestic spaces. However, free WiFi signals are noisy and uncertain, and their strengths and availability are continuously changing. Hence, we present a fuzzy logic-based system which employs free available WiFi signals to localize a given user in AIEs. The proposed system receives WiFi signals from a large number of existing WiFi access points (up to 170 access points), where no prior knowledge of the access points locations and the environment is required. The system employs an incremental lifelong learning approach to adjust its behavior to the varying and changing WiFi signals to provide a zero-cost localization system which can provide high accuracy in real-world living spaces. We have compared our system in both simulated and real environments with other relevant techniques in the literature, and we have found that our system outperfo- ms the other systems in the offline learning process, whereas our system was the only system which is capable of performing online learning and adaptation. The proposed system was tested in real-world spaces from a living lab intelligent apartment (iSpace) to a town center apartment to a block of offices. In all these experiments, our system has been highly accurate in detecting the user in the given AIEs, and the system was able to adapt its behavior to changes in the AIE or the WiFi signals. We envisage that the proposed system will play an important role in AIEs, especially for privacy concerned situations like elderly care scenarios.
Autors: Garcia-Valverde, T.;Garcia-Sola, A.;Hagras, H.;Dooley, J.A.;Callaghan, V.;Botia, J.A.;
Appeared in: IEEE Transactions on Fuzzy Systems
Publication date: Aug 2013, volume: 21, issue:4, pages: 702 - 718
Publisher: IEEE
 
» A generalized lumped element modeling of electrically and magnetically dual-tunable microwave magnetoelectric resonators
Abstract:
According to the microwave transmission principle and the mechanism of ferromagnetic resonance (FMR), a generalized lumped element modeling for magnetoelectric tunable resonators based on the inverse magnetoelectric effect is established taking the impact of equivalent factors of piezoelectric layer into consideration. The lumped element modeling is used to analyze the electrically and magnetically dual-tunable FMR frequency drift of the magnetoelectric tunable resonator; the prediction results have a good agreement with the experimental results and the electromagnetic simulation results in quality and quantity. On this basis, this lumped element modeling is used to predict the effect of the applied electric field, the microstrip's width, the substrate's thickness, and the size of ferrite-piezoelectric layered structure on the ferromagnetic resonance. The results show that with the increase of applied electric field, the values of equivalent resistance R, inductor L, and turns ratio n increase slightly, while the value of C decreases slightly, the FMR frequency fr positively shifts; with the increase of the microstrip's width and substrate's thickness, the values of equivalent resistance R, inductor L, and turns ratio n decrease, while the value of C increases, the FMR bandwidth becomes narrower, and the ferromagnetic resonance attenuation becomes stronger at the same time. When the applied electric field is determined, with the increase of the length or thickness of layered structure, the FMR frequency shifts forward, the FMR peak point decreases first and then increases; with the width of layered structure increases, the FMR frequency of the resonator shifts backward, the FMR peak point decreases first and then increases.
Autors: Zhou, Hao-Miao;Li, Chao;Zhu, Feng-Jie;Qu, Shao-Xing;
Appeared in: Journal of Applied Physics
Publication date: Aug 2013, volume: 114, issue:8, pages: 083902 - 083902-10
Publisher: IEEE
 
» A Geometrical View for Multiple Gross Errors Detection, Identification, and Correction in Power System State Estimation
Abstract:
Pub DtlIn this paper a geometrical approach is described to detect, identify, and recover multiple gross errors in power system state estimation. Using the classical WLS estimator, the measurement residuals is computed, and then the error is composed. For the detection and identification of the measurements with gross errors, the composed measurement error in the normalized form is used. The measurement magnitude corrections otherwise are performed using the composed normalized measurement error . To give support to the detection and identification of the measurements containing gross errors, a generalization of the classical largest normalized residual test is provided.
Autors: Bretas, N.G.;Piereti, S.A.;Bretas, A.S.;Martins, A.C.P.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Aug 2013, volume: 28, issue:3, pages: 2128 - 2135
Publisher: IEEE
 

Publication archives by date

  2017:   January     February     March     April     May     June     July     August     September     October     November     December    

  2016:   January     February     March     April     May     June     July     August     September     October     November     December    

  2015:   January     February     March     April     May     June     July     August     September     October     November     December    

  2014:   January     February     March     April     May     June     July     August     September     October     November     December    

  2013:   January     February     March     April     May     June     July     August     September     October     November     December    

  2012:   January     February     March     April     May     June     July     August     September     October     November     December    

  2011:   January     February     March     April     May     June     July     August     September     October     November     December    

  2010:   January     February     March     April     May     June     July     August     September     October     November     December    

  2009:   January     February     March     April     May     June     July     August     September     October     November     December    

 
0-C     D-L     M-R     S-Z