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Electrical and Electronics Engineering publications abstract of: 07-2013 sorted by title, page: 0
» 130-fold enhancement of TiO2 photocatalytic activities by ball milling
Abstract:
Submicrometer TiO2 particles were prepared by changing the mechanochemical parameters in planetary ball milling. The TiO2 particles before and after milling were characterized by five experimental methods. The photocatalytic activities of the TiO2 particles were evaluated by the photoreduction of an aqueous solution of methylene blue. The activity of milled TiO2 was 136 times that of TiO2 (anatase) before milling and 62 times that of commercial available TiO2 photocatalyst (P25). In addition to the reduction in particle size and increase in specific surface area due to milling, the disorder TiO2, involving amorphous and srilankite phases, significantly increased the catalytic performance.
Autors: Saitow, Ken-ichi;Wakamiya, Tomoji;
Appeared in: Applied Physics Letters
Publication date: Jul 2013, volume: 103, issue:3, pages: 031916 - 031916-5
Publisher: IEEE
 
» 3-D Analytical Linear Force and Rotary Torque Analysis of Linear and Rotary Permanent Magnet Actuator
Abstract:
This paper presents a 3-D analytical study of the linear electromagnetic force and rotary electromagnetic torque of a novel linear and rotary permanent magnet actuator (LRPMA). The 3-D analytical magnetic distribution of the LRPMA is established using the magnetic scalar potential and modified BESSEL functions in the cylindrical coordinate system. Linear electromagnetic force and rotary electromagnetic torque, respectively, are derived and verified using finite element method (FEM) for the characterization and optimization design of the LRPMA being examined by experiments in this paper.
Autors: Jin, P.;Lin, H.;Fang, S.;Yuan, Y.;Guo, Y.;Jia, Z.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2013, volume: 49, issue:7, pages: 3989 - 3992
Publisher: IEEE
 
» 3-D Magnetic-Near-Field Scanner for IC Chip-Level Noise Coupling Measurements
Abstract:
We present a 3-D magnetic-near-field scanner and a magnetic-near-field probe with a sensor head consisting of a on-chip coil. The 3-D scanner consists of an stage that positions the device under test with an accuracy of 10 and a stage that positions the probe and provides yaw-, pitch-, and roll-angle adjustment. The probe outputs are measured by a spectrum analyzer. Furthermore, we demonstrate and clarify the performance of a 1- -thick soft magnetic film as a noise suppressor. The film is integrated into a test element group (TEG) chip for next-generation cell phone handsets. The TEG chip is based on a long-term-evolution class complementary metal–oxide–semiconductor radio-frequency integrated circuit receiver. The CoZrNb film suppresses radiated emission by more than 15 dB. These results demonstrate the expected performance of the scanner and probe and the usefulness of the 1- -thick CoZrNb film as a noise suppressor.
Autors: Muroga, S.;Arai, K.;Dhungana, S.;Okuta, R.;Endo, Y.;Yamaguchi, M.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2013, volume: 49, issue:7, pages: 3886 - 3889
Publisher: IEEE
 
» 3-D Mapping of Sensitivity of Graphene Hall Devices to Local Magnetic and Electrical Fields
Abstract:
We report the response of sub-micron epitaxial graphene Hall devices to localized and inhomogeneous magnetic field produced by an MFM tip. We analyze the magneto-transport properties of epitaxial graphene and report the independent contribution of magnetic and electric fields in the measured transverse voltage maps with respect to the lateral and vertical position of the tip. A finite element model has also been developed to support the experimental results.
Autors: Rajkumar, R.K.;Manzin, A.;Cox, D.C.;Silva, S.R.P.;Tzalenchuk, A.;Kazakova, O.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2013, volume: 49, issue:7, pages: 3445 - 3448
Publisher: IEEE
 
» 3-D Reconstruction of the Spine From Biplanar Radiographs Based on Contour Matching Using the Hough Transform
Abstract:
The purpose of this study was to develop and evaluate a method for three-dimensional (3-D) reconstruction of the spine from biplanar radiographs. The approach was based on vertebral contour matching for estimating vertebral orientations and locations. Vertebral primitives were initially positioned under constraint of the 3-D spine midline, which was estimated from manually identified control points. Vertebral orientations and locations were automatically adjusted by matching projections of 3-D primitives with vertebral edges on biplanar radiographs based on the generalized Hough transform technique with a deformation tolerant matching strategy. We used graphics processing unit to accelerate reconstruction. Accuracy and precision were evaluated using radiographs from 15 scoliotic patients and a spine model in 24 poses. On in vivo radiographs, accuracy was within 2.8° for orientation and 2.4 mm for location; precision was within 2.3° for orientation and 2.1 mm for location. results were slightly better on model radiographs than on in vivo radiographs but without significance . The duration for user intervention was less than 2 min, and the computation time was within 3 min. Results indicated the method's reliability. It is a promising tool to determine 3-D spinal geometry with acceptable user interaction.
Autors: Zhang, J.;Lv, L.;Shi, X.;Wang, Y.;Guo, F.;Zhang, Y.;Li, H.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jul 2013, volume: 60, issue:7, pages: 1954 - 1964
Publisher: IEEE
 
» 3D Weakly Conditionally Stable FDTD Method for Analyzing Periodic Structures
Abstract:
By dividing the 3D transformed Maxwell's equations into two parts and applying the Crank-Nicolson (CN) scheme to each part, four sub-step implicit procedures are obtained. After adjusting the order of four sub-steps, a weakly conditionally stable finite-difference time-domain (WCS-FDTD) method is derived for solving the 3D problems of oblique incident plane wave on periodic structures. This method is very suitable for analyzing the problems which have fine structures in one or two directions, and the Courant–Friedrich–Levy (CFL) stability condition of it is more relaxed than that of the original field transformation methods. Numerical examples demonstrate that the presented technology is more efficient, especially at the high incident angle.
Autors: Wang, J.;Zhou, B.;Chen, B.;Gao, C.;Shi, L.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jul 2013, volume: 61, issue:7, pages: 3917 - 3921
Publisher: IEEE
 
» 60 Gbits error-free 4-PAM operation with 850 nm VCSEL
Abstract:
60 Gbits over 2 m, 50 Gbits over 50 m and 40 Gbits was transmitted over 100 m of OM4 multimode fibre using four-level pulse amplitude modulation and a directly modulated 850 nm vertical cavity surface emitting laser (VCSEL).
Autors: Szczerba, K.;Westbergh, P.;Karlsson, M.;Andrekson, P.A.;Larsson, A.;
Appeared in: Electronics Letters
Publication date: Jul 2013, volume: 49, issue:15
Publisher: IEEE
 
» 8- -Class Bit-Patterned Medium for Thermally Assisted Magnetic Recording
Abstract:
Three-dimensional optical/thermal spot profiles obtained by thermally assisted magnetic recording (TAMR) on bit-patterned media (BPM) with dot densities of 6 to 15 were numerically analyzed. Introduction of a spacing layer with higher thermal conductivity than that of the recording dots leads to narrow temperature distribution (i.e., steep temperature profile) in the dots. A temperature profile with FWHM of less than 5 nm was obtained on a patterned dot array under areal densities of 6 to 15 . In addition, introduction of a thermal-control layer beneath the recording layer decreased vertical temperature difference within a recording bit while keeping a narrow temperature distribution. Feasibility of 8- -class TAMR on a BPM was verified by LLG simulation with a triangular antenna-type near-field optical element.
Autors: Ushiyama, J.;Akagi, F.;Ando, A.;Miyamoto, H.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2013, volume: 49, issue:7, pages: 3612 - 3615
Publisher: IEEE
 
» 976 nm Single-Polarization Single-Frequency Ytterbium-Doped Phosphate Fiber Amplifiers
Abstract:
Core-pumped 976 nm single-polarization single-frequency fiber amplifiers based on several centimeter long polarization maintaining 6 wt% ytterbium doped phosphate fibers are investigated experimentally and numerically. A 350 mW linearly polarized output with polarization extinction ratio and optical signal-to-noise ratio is obtained from a 4 cm fiber amplifier at maximum available pump power of 793 mW. The slope efficiency of the 4 cm fiber amplifier is 52.5%. A small signal net gain of 25 dB, corresponding to a unit gain of over 6 dB/cm is achieved in this fiber. It is predicted that a watt level 976 nm core-pumped fiber amplifier can be achieved using more powerful pumps and low insertion loss optical components.
Autors: Zhu, X.;Zhu, G.;Shi, W.;Zong, J.;Wiersma, K.;Nguyen, D.;Norwood, R.A.;Chavez-Pirson, A.;Peyghambarian, N.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jul 2013, volume: 25, issue:14, pages: 1365 - 1368
Publisher: IEEE
 
» Ordered FePd, FePt, and CoPt Thin Films With Flat Surfaces Prepared on MgO(110) Single-Crystal Substrates
Abstract:
FePd, FePt, and CoPt alloy thin films are prepared on MgO(110) single-crystal substrates by using two different methods. One is one-step method consisting of deposition at an elevated substrate temperature of 600 C and the other is two-step method consisting of low-temperature deposition at 200 C followed by annealing at 600 C. The crystal structure, the crystallographic orientation, and the surface morphology are compared. ordered FePd, FePt, and CoPt films epitaxially grow on the substrates with three variants, (110), (101), and (011), when deposited at 600 C. The -axis of variant is lying in the film plane, whereas those of and variants are 45 canted from the substrate surface. Disordered FePd, FePt, and CoPt single-crystal films of (110) orientation are formed by deposition at 200 C. An - phase transformation occurs along , and $A1[001]$ by annealing the disordered films at 600 C. The annealed films thus consist of three variants. Similar final crystal structure and orientation are realized in the FePd, the FePt, and the CoPt films prepared by employing the two different methods. The ordered films prepared by one-step method have island-like surfaces involving facets, whereas those prepared by two-step method have very flat surfaces with the arithmetical mean roughness lower than 0.3 nm. The two-step method is useful for preparation of ordered films with flat surfaces.
Autors: Ohtake, M.;Itabashi, A.;Kirino, F.;Futamoto, M.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2013, volume: 49, issue:7, pages: 3295 - 3298
Publisher: IEEE
 
» -Band High Data-Rate I/Q Modulator and Demodulator With a Power-Locked Loop LO Source in 0.15- m GaAs pHEMT Technology
Abstract:
A wideband sub-harmonically pumped (SHP) modulator and demodulator fabricated in 0.15- m GaAs pseudomorphic high electron-mobility transistor technology are demonstrated in this paper. The chip is appropriate for emerging 60-GHz multi-gigabit communication applications. Digital modulation degradation resulting from in-phase/quadrature mismatch is effectively minimized by the proposed power-locked loop system. By overcoming the bandwidth limitations and quadrature errors in amplitude and phase, the sideband suppression ratio exhibits broadband performance with the feedback mechanism. By using the SHP mixer structure, the dc offset problem is mitigated because of decreased 2 local oscillator leakage. In addition, sub-circuit design considerations and feedback stability are described in this paper. The SHP modulator and demodulator demonstrate flat conversion-gain responses of dB and dB, respectively, from 51 to 68 GHz. Properties of multi-gigahertz modulation and demodulation bandwidths show the potentials for gigabit applications. The amplitude and phase imbalances are restricted within 0.3 dB and 5 , respectively, regardless of modulation or demodulation. High data-rate digital modulation and demodulation are successfully performed through 16-QAM and 64-QAM schemes within four channels of the IEEE 802.15.3c standard with outstanding error vector magnitude performances.
Autors: Tsai, Z.-M.;Liao, H.-C.;Hsiao, Y.-H.;Wang, H.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jul 2013, volume: 61, issue:7, pages: 2670 - 2684
Publisher: IEEE
 
» -Based Rare-Earth-Free Permanent-Magnet Alloys
Abstract:
This study presents the structural and magnetic properties of melt-spun , , and alloys. Appreciable permanent-magnet properties with a magnetocrystalline anisotropy of about 9.6–16.5 , a magnetic polarization –10.6 kG, and coercivities –3.0 kOe were obtained by varying the composition of these alloys. Structural analysis reveals that the positions of x-ray diffraction peaks of show good agreement with those corresponding to an orthorhombic structure having lattice parameters of about , , and . Based on these results, a model crystal structure for is developed and used to estimate the magnetic properties of using density-functional calculations, which agree with the experimental results.
Autors: Das, B.;Balamurugan, B.;Kumar, P.;Skomski, R.;Shah, V.R.;Shield, J.E.;Kashyap, A.;Sellmyer, D.J.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2013, volume: 49, issue:7, pages: 3330 - 3333
Publisher: IEEE
 
» -Process-Based Spin Manipulation in Magnetic Endohedral Fullerenes
Abstract:
Magnetic endohedral fullerenes hold much promise as the basic elements for realizing nanoscale devices such as molecular magnets, molecular memory devices, field effect transistors, and fullerene-based quantum computers. In this paper we take Co @C as an example to investigate the laser-induced, ultrafast, spin-dynamics mechanisms via processes. Fully ab initio calculations show that the spin density is localized at one of the Co atoms inside the carbon cage, indicating local spin manipulation possibility. It is found that the laser-induced ultrafast spin transfer in the endohedral fullerene can be achieved under the influence of circularly polarized light. The caging fullerene itself not only contributes to the spin localization of the whole system (on one of the two Co atoms at a time), but also amplifies the effect of the adopted laser pulse and gives an experimental possibility to produce isolated ensemble Co molecules. The predicted results and the physical mechanism unveiled in the present work are expected to shed some light on the application of magnetic elements embedded in fullerenes and other related nanomaterials as functional units in spin logic devices and to allow for application-oriented spin engineering.
Autors: Li, C.;Zhang, S.;Jin, W.;Lefkidis, G.;Hubner, W.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2013, volume: 49, issue:7, pages: 3195 - 3198
Publisher: IEEE
 
» -Band High Data-Rate I/Q Modulator and Demodulator With a Power-Locked Loop LO Source in 0.15- m GaAs pHEMT Technology
Abstract:
A wideband sub-harmonically pumped (SHP) modulator and demodulator fabricated in 0.15-μm GaAs pseudomorphic high electron-mobility transistor technology are demonstrated in this paper. The chip is appropriate for emerging 60-GHz multi-gigabit communication applications. Digital modulation degradation resulting from in-phase/quadrature mismatch is effectively minimized by the proposed power-locked loop system. By overcoming the bandwidth limitations and quadrature errors in amplitude and phase, the sideband suppression ratio exhibits broadband performance with the feedback mechanism. By using the SHP mixer structure, the dc offset problem is mitigated because of decreased 2× local oscillator leakage. In addition, sub-circuit design considerations and feedback stability are described in this paper. The SHP modulator and demodulator demonstrate flat conversion-gain responses of -14 ±2 dB and -14 ±1 dB, respectively, from 51 to 68 GHz. Properties of multi-gigahertz modulation and demodulation bandwidths show the potentials for gigabit applications. The amplitude and phase imbalances are restricted within 0.3 dB and 5° (±2.5°), respectively, regardless of modulation or demodulation. High data-rate digital modulation and demodulation are successfully performed through 16-QAM and 64-QAM schemes within four channels of the IEEE 802.15.3c standard with outstanding error vector magnitude performances.
Autors: Zuo-Min Tsai;Hsin-Chiang Liao;Yuan-Hung Hsiao;Huei Wang;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jul 2013, volume: 61, issue:7, pages: 2670 - 2684
Publisher: IEEE
 
» Hydrogen Resistive Gas Sensor and Its Wide-Range Current-Mode Electronic Read-Out Circuit
Abstract:
Tungsten oxide (WO3) thin films are prepared via sol-gel route by spinning (WCl6 in ethanol, 0.2 M) on Pt interdigitated Si/Si3N4 substrates and annealed at 300°C for 12, 24, 96, and 200 hours. Films morphology and crystalline phase are characterized through scanning electron microscopy, atomic force microscopy, and glancing angle X-ray diffraction. The increasing of the annealing time shows a positive effect on the degree of crystallization but with no substantial influence on the crystallite size, surface area, and mean roughness of the films. Electrical tests are carried out using a current-mode dedicated read-out circuit to perform gas-sensing measurements of the polycrystalline WO3 films to H2 gas (0-250 ppm) in dry air and operating temperatures ranging from 25 to 250°C. Electrical tests confirmed an n-type response of the films. Although improved sensitivity (S=RA/RSENS) is achieved when decreasing the annealing time, best performances in terms of reproducibility and long-term stability of the response are obtained by annealing the film for 200 hours at 300°C temperature.
Autors: De Marcellis, A.;Ferri, G.;Mantenuto, P.;Giancaterini, L.;Cantalini, C.;
Appeared in: IEEE Sensors Journal
Publication date: Jul 2013, volume: 13, issue:7, pages: 2792 - 2798
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: Jul 2013, volume: 19, issue:4, pages: 9 - 77
Publisher: IEEE
 
» A $40 software-defined radio [Resources_Hands On]
Abstract:
The last time I ventured into the waters of software-defined radio (SDR) was seven years ago, when I reviewed Matt Ettus's Universal Software Radio Peripheral. While it's an excellent product, the basic motherboard at the time cost US $550; daughterboards for different frequency ranges cost $75 to $275 [see "Hardware for Your Software Radio," IEEE Spectrum, October 2006]. And I spent more than a few frustrating hours compiling the needed software on my MacBook Pro. This time I was able to get my feet wet for about $40–and the software took about 2 minutes to download, install, and run.
Autors: Cass, S.;
Appeared in: IEEE Spectrum
Publication date: Jul 2013, volume: 50, issue:7, pages: 22 - 23
Publisher: IEEE
 
» A 0.007- 108- 1-MHz Relaxation Oscillator for High-Temperature Applications up to 180 in 0.13- CMOS
Abstract:
Pub DtlReliable high-temperature CMOS oscillators are required for clock or time-base generation in several applications including data acquisition for aerospace, automotive control, oil field instrumentation, and pulp and paper digesters. In this paper, we present low-complexity resistive and capacitive temperature-compensation techniques for CMOS relaxation oscillators. In such oscillators, the frequency of oscillation is a function of a resistor-capacitor product. The resistive compensation technique employs a recently proposed monolithic resistor with a given temperature coefficient (TC) that uses contacts to adjust the TC of the resistor. The capacitive compensation technique is based on using a varactor to adjust the value of the timing capacitance over temperature to compensate for the high-temperature junction leakage current and to keep the oscillation frequency relatively constant. A prototype oscillator based on the proposed techniques is implemented in a standard 0.13- CMOS process and reliably operates over 25 to 180 . Measured results show that over the temperature range of interest the compensated oscillator achieves a temperature coefficient of 108 . The oscillator along with its output drivers occupies 7200 (2.3 to 114 smaller than state-of-the-art designs) and consumes 428 from a 2.5 V supply. For supply variations between 2 and 3 V, the frequency variation is $pm 1.09% /{rm V}$.
Autors: Sadeghi, N.;Sharif-Bakhtiar, A.;Mirabbasi, S.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jul 2013, volume: 60, issue:7, pages: 1692 - 1701
Publisher: IEEE
 
» A 10-Gbit/s Wireless Communication Link Using 16-QAM Modulation in 140-GHz Band
Abstract:
This paper describes a 140-GHz wireless link whose maximum transmission data rate is 10 Gbit/s. A sub-harmonic mixer and multiplier based on Schottky barrier diodes, a waveguide H ladder bandpass filter, a Cassegrain antenna, and other components have been developed to construct a high-performance transmitting and receiving front end. 16 quadrature amplitude modulation has been adopted to improve the spectrum efficiency to 2.86-bit/s/Hz. A 32-way parallel demodulation architecture based on frequency-domain implementation of the matched filter and timing phase correction is proposed. An adaptive blind equalization algorithm is also realized to enhance the tolerance for channel distortion. The modulated signal is centered at 140.3 GHz with -dBm output power. This link succeeded in transmission of a 10-Gbit/s signal over a 1.5-km distance with a bit error rate of 1e-6 in non-real-time mode. The measured 99.99% power bandwidth of the 10-Gbit/s signal is 3.6 GHz. The lowest acceptable signal noise rate per bit ( ) is 15 dB. This link also transmitted a 2-Gbit/s real-time signal with lowest .
Autors: Wang, C.;Lin, C.;Chen, Q.;Lu, B.;Deng, X.;Zhang, J.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jul 2013, volume: 61, issue:7, pages: 2737 - 2746
Publisher: IEEE
 
» A 15-bit 140- W Scalable-Bandwidth Inverter-Based Modulator for a MEMS Microphone With Digital Output
Abstract:
A discrete-time audio ΔΣ modulator for a MEMS microphone with digital output is presented that features a scalable signal bandwidth to also support ultrasonic frequencies for proximity sensing applications such as gesture recognition. The modulator achieves low power consumption and a small die area by using simple digital inverter instead of OTAs. To increase the robustness of the inverter approach, an LDO is used to provide an internally generated supply which regulates the inverter bias point. The LDO also improves the power supply rejection of the pseudo-differential architecture to above 78 dB. The presented ΔΣ modulator supports a scalable signal bandwidth up to 100 kHz, by dynamically adjusting the internal supply voltage depending on the sampling frequency. In the nominal 20-kHz audio band, it dissipates 140 μW from a minimum 1.5-V supply and achieves a DR of 92.6 dB , a SNDR of 87.9 dB, and a THD of -102.7 dB, respectively.
Autors: Christen, T.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2013, volume: 48, issue:7, pages: 1605 - 1614
Publisher: IEEE
 
» A 15-bit 140- W Scalable-Bandwidth Inverter-Based Modulator for a MEMS Microphone With Digital Output
Abstract:
A discrete-time audio modulator for a MEMS microphone with digital output is presented that features a scalable signal bandwidth to also support ultrasonic frequencies for proximity sensing applications such as gesture recognition. The modulator achieves low power consumption and a small die area by using simple digital inverter instead of OTAs. To increase the robustness of the inverter approach, an LDO is used to provide an internally generated supply which regulates the inverter bias point. The LDO also improves the power supply rejection of the pseudo-differential architecture to above 78 dB. The presented modulator supports a scalable signal bandwidth up to 100 kHz, by dynamically adjusting the internal supply voltage depending on the sampling frequency. In the nominal 20-kHz audio band, it dissipates 140 from a minimum 1.5-V supply and achieves a DR of 92.6 dB , a SNDR of 87.9 dB, and a THD of , respectively.
Autors: Christen, T.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2013, volume: 48, issue:7, pages: 1605 - 1614
Publisher: IEEE
 
» A 2-Kb One-Time Programmable Memory for UHF Passive RFID Tag IC in a Standard 0.18 m CMOS Process
Abstract:
We present a 2-Kb one-time programmable (OTP) memory for UHF RFID applications. The OTP memory cell is based on a two-transistor (2-T) gate-oxide anti-fuse (AF) for low voltage operation. Reliability of memory cell is enhanced by limiting the maximum terminal voltages of thin-oxide and thick-oxide transistors to 1.8 V and 3.3 V, respectively. Improved low power circuit design techniques are used including auto shut-off for program mode and self-timed control for read mode. To further reduce power consumption, we develop a novel power-efficient charge pump. The designed OTP is successfully embedded into a UHF passive RFID tag IC that conforms to the EPCglobal Gen-2 standard. The tag chip was fabricated in a 0.18 1-poly 6-metal standard CMOS process with no additional masks. The total area of the chip including the I/Os and bonding pads is where the OTP memory area is only . Our tag IC measurement shows that the read and write currents of the OTP memory are 17 and 58 , respectively.
Autors: Phan, N.D.;Chang, I.K.;Lee, J.-W.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jul 2013, volume: 60, issue:7, pages: 1810 - 1822
Publisher: IEEE
 
» A 2.0 Gb/s Throughput Decoder for QC-LDPC Convolutional Codes
Abstract:
Pub DtlThis paper proposes a decoder architecture for low-density parity-check convolutional code (LDPCCC). Specifically, the LDPCCC is derived from a quasi-cyclic (QC) LDPC block code. By making use of the quasi-cyclic structure, the proposed LDPCCC decoder adopts a dynamic message storage in the memory and uses a simple address controller. The decoder efficiently combines the memories in the pipelining processors into a large memory block so as to take advantage of the data-width of the embedded memory in a modern field-programmable gate array (FPGA). A rate-5/6 QC-LDPCCC has been implemented on an Altera Stratix FPGA. It achieves up to 2.0 Gb/s throughput with a clock frequency of 100 MHz. Moreover, the decoder displays an excellent error performance of lower than 10 at a bit-energy-to-noise power-spectral-density ratio of 3.55 dB.
Autors: Sham, C.-W.;Chen, X.;Lau, F.C.M.;Zhao, Y.;Tam, W.M.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jul 2013, volume: 60, issue:7, pages: 1857 - 1869
Publisher: IEEE
 
» A 2.4-GHz MEMS-Based PLL-Free Multi-Channel Receiver With Channel Filtering at RF
Abstract:
A Bulk Acoustic Wave (BAW) resonator based 2.4-GHz low power receiver is presented in this work. The intrinsic high quality factor ( ) of the BAW resonator (around 400 at 2.4-GHz) is exploited to provide channel selection at RF and in the frequency synthesis. A novel way of addressing multiple channels (arbitrary frequency) using integer dividers and a BAW digitally controlled oscillator (DCO) and thus avoiding the need for a PLL is proposed in this work. To the best of our knowledge, this work is the first one to report a multi-channel (arbitrary frequency) receiver whose frequency synthesis depends solely on the low phase noise BAW DCO and does not include a PLL. A BAW pseudo-lattice with frequency and bandwidth tuning is proposed which significantly improves the rejection of unwanted signals in the channel filter. A quadrature sub-sampling mixer is used to down-convert the selected channel to baseband. The receiver is designed and integrated in a 0.18- CMOS process. With -boosting, the channel filter provides bandwidth down-to 1-MHz. For a BFSK modulated signal, the receiver exhibits a sensitivity of at a rate of 268-kbps for a BER of . The total power consumption of the receiver is 5.94-mA from a 1.8-V power supply.
Autors: Heragu, A.;Ruffieux, D.;Enz, C.C.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2013, volume: 48, issue:7, pages: 1689 - 1700
Publisher: IEEE
 
» A 20-Mb/s Pulse Harmonic Modulation Transceiver for Wideband Near-Field Data Transmission
Abstract:
This brief presents a fully integrated low-power transceiver for wideband near-field data transmission across inductive telemetry links based on pulse harmonic modulation (PHM). This PHM transceiver uses two narrow pulses with specific amplitudes and timing at the transmitter (Tx) to suppress intersymbol interference (ISI) at the receiver (Rx) high-   tank to achieve high data rates (DRs) without reducing the inductive link quality factor to extend its bandwidth. This method significantly improves the range and selectivity of the link. The PHM Rx architecture is based on noncoherent energy detection utilizing a novel pulse-based automatic gain control circuit, which significantly reduces the power consumption (46%) and ISI at short coupling distances. The PHM transceiver was fabricated in a 0.35- standard CMOS process and achieved a measured DR of 20 Mb/s with a bit error rate of at a 10-mm distance using planar figure-8 coils. The PHM Tx and Rx power consumptions were 180 and 12.15 pJ/bit, respectively, at a 1.8-V supply voltage.
Autors: Kiani, M.;Ghovanloo, M.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jul 2013, volume: 60, issue:7, pages: 382 - 386
Publisher: IEEE
 
» A 265 V Mains Interface Integrated in 0.35 m CMOS
Abstract:
A fully integrated 265 VRMS input AC-DC interface is demonstrated in a 0.35-μm CMOS technology, requiring only one optional external low-voltage SMD capacitor for improved performance. The converter can directly interface the universal line voltage (50-60 Hz) and converts this into a regulated DC voltage of 3.3 V. High input voltage operation is made possible through separation of the mains input from the active circuits by custom layout high-voltage capable passive components in between. A compact model of an ideal AC-DC capacitive step-down converter is presented and the proposed circuit architecture is designed to mimic ideal operation and approach the maximum attainable power throughput accordingly. The prototype converter demonstrates a maximum output power of 12.7 μW on a die area of 6 mm2 and enables integrated circuits to be supplied straight from the ubiquitous mains voltage, hereby circumventing the need for traditional converters using expensive and bulky high-voltage discrete components.
Autors: Meyvaert, H.;Smeets, P.;Steyaert, M.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2013, volume: 48, issue:7, pages: 1558 - 1564
Publisher: IEEE
 
» A 265 V Mains Interface Integrated in 0.35 m CMOS
Abstract:
A fully integrated 265 V input AC–DC interface is demonstrated in a 0.35- m CMOS technology, requiring only one optional external low-voltage SMD capacitor for improved performance. The converter can directly interface the universal line voltage (50–60 Hz) and converts this into a regulated DC voltage of 3.3 V. High input voltage operation is made possible through separation of the mains input from the active circuits by custom layout high-voltage capable passive components in between. A compact model of an ideal AC–DC capacitive step-down converter is presented and the proposed circuit architecture is designed to mimic ideal operation and approach the maximum attainable power throughput accordingly. The prototype converter demonstrates a maximum output power of 12.7 W on a die area of 6 mm and enables integrated circuits to be supplied straight from the ubiquitous mains voltage, hereby circumventing the need for traditional converters using expensive and bulky high-voltage discrete components.
Autors: Meyvaert, H.;Smeets, P.;Steyaert, M.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2013, volume: 48, issue:7, pages: 1558 - 1564
Publisher: IEEE
 
» A 288-GHz Lens-Integrated Balanced Triple-Push Source in a 65-nm CMOS Technology
Abstract:
A 288-GHz lens-integrated high-power source implemented in a 65-nm CMOS technology is presented. The source consists of two free-running triple-push ring oscillators locked out-of phase by magnetic coupling. The oscillators drive a differential on-chip ring antenna, which illuminates a hyper-hemispherical silicon lens through the backside of the die. An on-wafer breakout of the oscillators core achieves a peak output power of 1.5 dBm with a 275-mW DC power consumption. The radiated power of the packaged source is 4.1 dBm, which is the highest reported radiated power of a single CMOS source beyond 200 GHz. The source die including the antenna occupies only 500 x 570 m .
Autors: Grzyb, J.;Zhao, Y.;Pfeiffer, U.R.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2013, volume: 48, issue:7, pages: 1751 - 1761
Publisher: IEEE
 
» A 375 mW Multimode DAC-Based Transmitter With 2.2 GHz Signal Bandwidth and In-Band IM3 58 dBc in 40 nm CMOS
Abstract:
A 40 nm CMOS digital-to-analog converter (DAC) based multimode transmitter (MMTX) is presented. The transmitter can be operated in either narrow- or wideband applications. It has a maximum 2.2 GHz signal bandwidth and exhibits an in-band IM3 of less than - 58 dBc. The MMTX consists of a current-steering DAC with digital sinc equalization and rolloff compensation. By implementing high-speed, feed-forward pipelined digital logic and a distributed decoder, the DAC sampling rate extends to 5 GHz. A distributed regulator approach ensures preservation of the achieved wideband linearity in noisy embedded SoC environments. The MMTX can deliver up to +11 dBm of output power and exhibits 20 dB of analog power backoff with 1 dB steps and a precision better than ±0.1 dB. The MMTX consumes only 375 mW and occupies 1.65 mm2.
Autors: Spiridon, S.;van der Tang, J.;Han Yan;Hua-Feng Chen;Guermandi, D.;Xiaodong Liu;Arslan, E.;van der Goes, F.;Bult, K.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2013, volume: 48, issue:7, pages: 1595 - 1604
Publisher: IEEE
 
» A 5-GHz CMOS LC Quadrature VCO With Dynamic Current-Clipping Coupling to Improve Phase Noise and Phase Accuracy
Abstract:
This paper presents a quadrature voltage-controlled oscillator (QVCO) employing a proposed dynamic current-clipping coupling technique to provide around 90° phase shift in the coupling paths. The phase shift given by the coupling network not only improves the phase noise, but also desensitizes the phase error to component mismatches in the QVCO. The coupling network furthermore reduces the noise injected into the tank at the most vulnerable time (zero crossing points). The proposed current-clipping coupling allows the use of a strong coupling ratio to minimize the quadrature phase sensitivity to mismatches without degrading the phase noise performance. The proposed QVCO is implemented in a 130-nm CMOS technology. The measured phase noise is 121 dBc/Hz at 1-MHz offset from a 5-GHz carrier. The QVCO consumes 4.2 mW from a 1-V power supply, resulting in an outstanding figure of merit of 189 dBc/Hz.
Autors: Lo, Y.-C.;Silva-Martinez, J.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jul 2013, volume: 61, issue:7, pages: 2632 - 2640
Publisher: IEEE
 
» A 60-GHz Band Planar Dipole Array Antenna Using 3-D SiP Structure in Small Wireless Terminals for Beamforming Applications
Abstract:
Pub DtlA 60-GHz band planar dipole array antenna structure in a small wireless terminal is proposed for wide coverage area beamforming applications. Several substrates are stacked vertically by using 3-D system-in-package (SiP) technology, and the element antenna is installed on the substrates. A planar dipole antenna is used as an element antenna because it has a wider bandwidth than conventional patch antennas, which are widely used in 60-GHz band beamforming applications. Conventional dipole array antennas have a 1-D structure, or a 2-D structure arranged in multilayered substrate, resulting in narrow beamforming coverage area. The proposed structure has a wide beamforming coverage area because of the wide antenna spacing around . Design using numerical and 3-D electromagnetic field simulation indicate that a 4 2 arrangement is a feasible structure for a small wireless terminal with wide coverage area. Measurement results show that the designed array antenna has a wide coverage area, covering 75 and 95 in the theta and phi directions, respectively, with gain exceeding 10 dBi. The proposed planar dipole array structure using 3-D SiP technology is feasible as a 60-GHz band 2-D beamforming antenna in small wireless terminals.
Autors: Yoshida, S.;Suzuki, Y.;Ta, T.T.;Kameda, S.;Suematsu, N.;Takagi, T.;Tsubouchi, K.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jul 2013, volume: 61, issue:7, pages: 3502 - 3510
Publisher: IEEE
 
» A 65-nm CMOS 1.75–15 GHz Stepped Frequency Radar Receiver for Early Diagnosis of Breast Cancer
Abstract:
A 65-nm CMOS receiver tailored for breast cancer diagnostic imaging is demonstrated for the first time. The receiver shows 31-dB conversion gain, , , and over a band from 1.75 to 15 GHz. A programmable injection-locked divider generates quadrature LO signals with a I/Q phase error over three octaves without requiring any calibration or tuning. The receiver shows a flicker noise corner as low as 40 Hz, achieving a dynamic range of 106 dB.
Autors: Bassi, M.;Caruso, M.;Bevilacqua, A.;Neviani, A.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2013, volume: 48, issue:7, pages: 1741 - 1750
Publisher: IEEE
 
» A 67 GHz GaN Voltage-Controlled Oscillator MMIC With High Output Power
Abstract:
This letter describes the design and the realization of a fixed-frequency oscillator and voltage-controlled oscillator (VCO) MMIC realized in an AlGaN/GaN HEMT technology with 100 nm gate length. Both oscillators achieve output power levels of almost 20 dBm without post-amplification. The oscillation frequency of the fixed-frequency oscillator is 65.6 GHz, while the VCO can be tuned from 65.6 to 68.8 GHz, which leads to a relative bandwidth of 5%. The phase noise of the VCO is dBc/Hz at 1 MHz frequency offset.
Autors: Weber, R.;Schwantuschke, D.;Bruckner, P.;Quay, R.;Mikulla, M.;Ambacher, O.;Kallfass, I.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jul 2013, volume: 23, issue:7, pages: 374 - 376
Publisher: IEEE
 
» A 77-GHz CMOS FMCW Frequency Synthesizer With Reconfigurable Chirps
Abstract:
This paper presents a 77-GHz CMOS frequency-modulated continuous-wave (FMCW) frequency synthesizer with the capability of reconfigurable chirps. The frequency-sweep range and sweep time of the chirp signals can be reconfigured every cycle such that the frequency-hopping random chirp signal can be realized for an FMCW radar transceiver. The frequency synthesizer adopts the fractional- phase-locked-loop technique and is fully integrated in TSMC 65-nm digital CMOS technology. The silicon area of the synthesizer is 0.65 mm 0.45 mm and it consumes 51.3 mW of power. The measured output phase noise of the synthesizer is 85.1 dBc/Hz at 1-MHz offset and the root-mean-square modulation frequency error is smaller than 73 kHz.
Autors: Luo, T.-N.;Wu, C.-H.E.;Chen, Y.-J.E.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jul 2013, volume: 61, issue:7, pages: 2641 - 2647
Publisher: IEEE
 
» A 77-GHz CMOS Power Amplifier With a Parallel Power Combiner Based on Transmission-Line Transformer
Abstract:
This paper presents a 77-GHz CMOS power amplifier (PA) with a parallel power combiner based on a transmission-line transformer (TLT). An inter-stage matched cascode power cell structure is applied to obtain high output power and efficiency, where a simple matching network between the common-gate and common-source stage is introduced. The parallel power combiner based on a broadside-coupled TLT is analyzed and compared with a series power combiner. The PA is fabricated using a 65-nm RF CMOS process. It achieves the saturated output power of 15.8 dBm, the power-added efficiency of 15.2%, and the power gain of 20.9 dB with a supply voltage of 2.0 V at 77 GHz.
Autors: Oh, J.;Ku, B.;Hong, S.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jul 2013, volume: 61, issue:7, pages: 2662 - 2669
Publisher: IEEE
 
» A 9-dBm Output Active Feedback CMOS Wideband LNA for SAW-Less Receivers
Abstract:
A highly linear complementary source follower (CSF) feedback CMOS wideband LNA is implemented as a part of a highly linear receiver front end resilient to 0-dBm out-of-band blockers. Due to the linear feedback operation of the CSF, the proposed LNA greatly improves large-signal linearity performances compared to the conventional SF feedback LNA. The proposed feedback LNA shows an input close to 0 dBm while achieving an input reflection coefficient less than 10 dB, an average power gain of 10 dB, and a minimum noise figure of 3 dB. The power consumption is 18 mW at a 2-V supply voltage.
Autors: Im, D.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jul 2013, volume: 60, issue:7, pages: 377 - 381
Publisher: IEEE
 
» A 9-dBm Output Active Feedback CMOS Wideband LNA for SAW-Less Receivers
Abstract:
A highly linear complementary source follower (CSF) feedback CMOS wideband LNA is implemented as a part of a highly linear receiver front end resilient to 0-dBm out-of-band blockers. Due to the linear feedback operation of the CSF, the proposed LNA greatly improves large-signal linearity performances compared to the conventional SF feedback LNA. The proposed feedback LNA shows an input close to 0 dBm while achieving an input reflection coefficient less than 10 dB, an average power gain of 10 dB, and a minimum noise figure of 3 dB. The power consumption is 18 mW at a 2-V supply voltage.
Autors: Im, D.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jul 2013, volume: 60, issue:7, pages: 377 - 381
Publisher: IEEE
 
» A Bankruptcy Game-Based Resource Allocation Approach among Virtual Mobile Operators
Abstract:
Network virtualization (NV) has attracted more and more attentions from research communities. Introduction of virtualization technology to cellular networks is a promising solution for higher resource utilization, improved system performance, and lower investment capitals for mobile operators. In this letter, the work is focused on allocating wireless resources among multiple virtual mobile operators (VMOs). A bankruptcy game based dynamic wireless resource allocation approach among multiple VMOs is proposed and investigated. The satisfaction of payoffs (i.e., resources) each VMO is paid is evaluated with expectation index (EI). Particularly, the Long Term Evolution (LTE) is chosen as the case study to evaluate the proposed approach.
Autors: Liu, Bin;Tian, Hui;
Appeared in: IEEE Communications Letters
Publication date: Jul 2013, volume: 17, issue:7, pages: 1420 - 1423
Publisher: IEEE
 
» A Batteryless RFID Remote Control System
Abstract:
This paper presents a novel eco-friendly batteryless remote control (RC) system based on a multi-RF identification (RFID) scheme. The proposed RC device does not require the use of batteries or other installed power source. Instead, it relies on passive RFID chips that are remotely powered by an RFID reader. The controlled device (e.g., a TV) incorporates an RFID reader to power up and communicate with the RC. The proposed batteryless RC is composed of an antenna, a plurality of passive RFID chips and switches, and a multi-port microstrip network that interconnects the various RFID chips, allowing them to share a common antenna. Each key of the RC is associated to an RFID with a unique identifier, which allows the device to be controlled to identify the key pressed by the user. The proposed arrangement ensures that only the chip associated to the pressed key is read by the RFID reader, while the other chips remain inactive. First of all, the system is described including the multi-RFID scheme and the proposed multi-port network. Afterword, a characterization of the contact switches and RFID chips is performed. This is followed by RFID chip impedance matching and switch tuning. A multi-port network is fabricated (in low-cost FR4) and measured in order to access network's behavior depending on some parameters such as the number of ports and distance from the active port to the antenna. Finally, a four-key RC unit is prototyped, and an RFID reader system is integrated in a TV by using an external RFID-to-infrared interface. Four control functionalities are implemented and tested (CH , CH , Vol , and Vol$-$ ). Measurements are also conducted to evaluate the system coverage range and line-of-sight capability.
Autors: Boaventura, A.J.S.;Carvalho, N.B.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jul 2013, volume: 61, issue:7, pages: 2727 - 2736
Publisher: IEEE
 
» A Bidirectional-Concurrent MAC Protocol With Packet Bursting for Underwater Acoustic Networks
Abstract:
Pub DtlThe underwater acoustic channel is fundamentally different from the terrestrial wireless channel. Its unique characteristics, such as slow propagation speed and small bit rate distance product, present both challenges and opportunities for media access control (MAC) protocol design. In existing handshaking-based MAC protocols, each successful handshake only allows an initiating sender to transmit a single or multiple consecutive data packets to its intended receiver. In a long propagation delay environment, this unidirectional data transmission often results in extremely poor channel utilization due to the long waiting time for the handshake to complete. By exploiting the channel's unique characteristics, we present a novel approach based on concurrent, bidirectional data packet exchange to improve the data transmission efficiency. To further amortize the high latency overhead, we adopt a packet bursting idea, where a sender–receiver pair can exchange multiple rounds of bidirectional packet transmissions. Based on these strategies, we propose an asynchronous handshaking-based MAC protocol, which we call bidirectional-concurrent MAC with packet bursting (BiC–MAC). Via extensive simulations, we compare BiC–MAC against two representative unidirectional handshaking-based protocols, as well as several existing MAC protocols. We demonstrate that BiC–MAC can significantly increase channel utilization and offer performance gains in terms of both throughput and delay, while achieving a stable saturation throughput. Our study highlights the value of adopting bidirectional, concurrent transmission in underwater networks.
Autors: Ng, H.-H.;Soh, W.-S.;Motani, M.;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jul 2013, volume: 38, issue:3, pages: 547 - 565
Publisher: IEEE
 
» A Bistatic Synthetic Aperture Radar Imagery Simulation of Maritime Scene Using the Extended Nonlinear Chirp Scaling Algorithm
Abstract:
A bistatic synthetic aperture radar (Bis-SAR) imagery simulation of an extended maritime scene is presented. An efficient facet scattering model is developed to collect the raw coupling scattering data from a ship located on sea surface. Then, to avoid the inefficiency of time-domain algorithms and the azimuth-invariant limit of conventional frequency-domain (FD) methods in the bistatic case, an extended nonlinear chirp scaling (NLCS) algorithm is proposed to handle the bistatic data collected from this facet scattering model. The perfect Bis-SAR simulation results of the ship located on the sea surface could prove the validity of the proposed algorithms as well as the practicability of the model for the Bis-SAR imagery with large squint angle in the FD approach.
Autors: Zhang, Min;Zhao, Yan-Wei;Zhao, Ye;Chen, Hui;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Jul 2013, volume: 49, issue:3, pages: 2046 - 2054
Publisher: IEEE
 
» A Bounded and Discretized Nelder-Mead Algorithm Suitable for RFIC Calibration
Abstract:
This paper describes a calibration technique for noisy and nonconvex circuit responses based on the Nelder-Mead direct search algorithm. As Nelder-Mead is intended for unconstrained optimization problems, we present an implementation of the algorithm which is suitable for bounded and discretized RFIC calibration problems. We apply the proposed algorithm to the problem of spurious tone reduction via VCO control line ripple minimization for a PLL operating at a frequency of 12 GHz. For this nonconvex calibration test case, we show that a gradient descent-based algorithm has difficulty in reducing the VCO control line ripple, while the proposed algorithm reduces the relative power of the first harmonic reference spurs by at least 10 dBc and effectively enables design complexity reduction in the supporting analog calibration circuitry.
Autors: Wyers, E.J.;Steer, M.B.;Kelley, C.T.;Franzon, P.D.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jul 2013, volume: 60, issue:7, pages: 1787 - 1799
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: Jul 2013, volume: 49, issue:4, pages: 1566 - 1576
Publisher: IEEE
 
» A case study on U.S. government military standard development
Abstract:
Developing standards normally arises out of a perceived need for commonality to obtain interoperability, cost savings, or logistics benefits. The multiplexed data bus concept was a perceived need by the digital engineering community but considered a high risk by management. A lack of understanding for those outside the engineering field induced this risk element. We had to educate and “sell” the concept first to them. We highlighted all the benefits to them, the flexibility, the plug-and-play capability, the reduced logistics, and cost savings. All this did not sway them until they were in a bind, then weight savings was the acceptance criteria. Even though important, weight savings was not the only benefit. Creating new standards requires persistence, compromise, and time to develop. Salesmanship is as important as engineering competence. Demonstrations and proof of concept are critical. And finally, it was found that the best standards are those where the government works hand in hand with the applicable industry to get everyone's buy in.
Autors: Gangl, Erwin C.;
Appeared in: IEEE Aerospace and Electronic Systems Magazine
Publication date: Jul 2013, volume: 28, issue:7, pages: 40 - 45
Publisher: IEEE
 
» A CMOS WCDMA/WLAN Digital Polar Transmitter With AM Replica Feedback Linearization
Abstract:
This paper presents a 65 nm CMOS digital polar transmitter with on-chip power amplifier (PA) for WCDMA and WLAN application. The proposed architecture is composed of a digital interpolation filter for up-sampling of the input amplitude-control word (ACW), a 9-bit switched-capacitor array for the digital polar modulation (DPM), and a 6-bit PA array to achieve the output power range for the target applications. A linearization technique is implemented by adaptively changing the PA bias voltage according to the RF envelope. To generate this bias voltage, the RF envelope of the PA input is extracted by a digital-to-analog converter (DAC) with the ACW signals as its input. A scaled replica of the PA, which only needs to operate at the Amplitude Modulation (AM) frequency, is employed to sense the RF envelope and to regulate the PA bias voltage with an analog feedback loop to minimize the distortion in the AM path. Even without amplitude pre-distortion, the transmitter system measures RMS-EVM of 2.83% and 4.07% for WCDMA and WLAN 54-Mb/s 64-QAM OFDM respectively while providing a peak output power of 20.4 dBm with PAE 32.3%.
Autors: Zheng, S.;Luong, H.C.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2013, volume: 48, issue:7, pages: 1701 - 1709
Publisher: IEEE
 
» A Color Ratio Method for Simultaneous Retrieval of Aerosol and Cloud Optical Thickness of Above-Cloud Absorbing Aerosols From Passive Sensors: Application to MODIS Measurements
Abstract:
The presence of absorbing aerosols above cloud decks reduces the amount of upwelling ultraviolet (UV), visible (VIS), and shortwave infrared radiation reaching the top of atmosphere. This effect is often referred to as “cloud darkening,” which can be seen by eye in images and quantitatively in the spectral reflectance measurements made by passive sensors such as the Moderate Resolution Imaging Spectroradiometer (MODIS) in the regions where light-absorbing carbonaceous and dust aerosols overlay low-level clouds. Radiative transfer simulations support the observational evidence and further reveal that the reduction in the spectral reflectance and color ratio between a pair of wavelengths is a function of both aerosol and cloud optical thickness (AOT and COT). For a prescribed set of aerosol and cloud properties and their vertical profiles, thus, the measured reflectance can be associated with a pair of AOT and COT. Based on these results, a retrieval technique has been developed, which is named as the “color ratio method,” which utilizes the measurements at a shorter (470 nm) and a longer (860 nm) wavelength for the simultaneous derivation of AOT and COT. The retrieval technique has been applied to the MODIS 1-km reflectance measurements for the two distinct above-cloud smoke and dust aerosols events. This study is an extension of the previously developed near-UV method to the VIS spectral region. However, it constitutes the first attempt to use non-UV wavelengths to retrieve above-cloud AOT by a passive nonpolarized sensor. An uncertainty analysis has been presented, which estimates the expected error associated with these retrievals.
Autors: Jethva, H.;Torres, O.;Remer, L.A.;Bhartia, Pawan K.;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Jul 2013, volume: 51, issue:7, pages: 3862 - 3870
Publisher: IEEE
 
» A combined electron-ion spectrometer for studying complete kinematics of molecular dissociation upon shell selective ionization
Abstract:
A combined electron-ion spectrometer has been built to study dissociation kinematics of molecular ions upon various electronic decay processes ensuing from ionization of neutral molecules. The apparatus can be used with various ionization agents. Ion time-of-flight (ToF) spectra arising from various electronic decay processes are acquired by triggering the ToF measurement in coincidence with energy analyzed electrons. The design and the performance of the spectrometer in a photoionization experiment is presented in detail. Electron spectra and ion time of flight spectra resulting from valence and 2p1/2 ionization of Argon and those from valence ionization of CO are presented to demonstrate the capability of the instrument. The fragment ion spectra show remarkable differences (both kinematic and cross sectional) dependent on the energy of the ejected electron, corresponding to various electron loss and decay mechanisms in dissociative photoionization of molecules.
Autors: Saha, K.;Banerjee, S.B.;Bapat, B.;
Appeared in: Review of Scientific Instruments
Publication date: Jul 2013, volume: 84, issue:7, pages: 073101 - 073101-8
Publisher: IEEE
 
» A Compact DBR Filter Using -Network and Dual-Line Equivalent Circuit
Abstract:
This letter presents a new design structure for compact Dual Behavior Resonator (DBR) filter using -Network and dual-line equivalent circuits. The proposed -Network replaces the J-inverter in DBR filter, which consists of a high impedance transmission line and parallel capacitances loaded on both sides, where the parallel capacitances can be integrated into neighboring resonators. The dual-line structure is used to replace open-circuited transmission line segment. The relevant equations of the proposed filter are derived. The whole structures have the advantages of better out-of-band rejection and easy fabrication. A 3-order DBR filter is designed and measured. Its size is only 28% of the classical one, and experiment results are in good agreement with simulation results.
Autors: Su, T.;Wang, S.-J.;Zhang, Y.-L.;Li, Z.-P.;Zhang, L.-J.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jul 2013, volume: 23, issue:7, pages: 350 - 352
Publisher: IEEE
 
» A Computationally Efficient CFAR Algorithm Based on a Goodness-of-Fit Test for Piecewise Homogeneous Environments
Abstract:
A new constant false alarm rate (CFAR) detection algorithm operating in nonhomogeneous clutter is proposed. The proposed CFAR algorithm, cell-under-test (CUT) inclusive (CI) CFAR, utilizes a goodness-of-fit test for determining and combining homogeneous windows, which results in a higher detection performance. The CI-CFAR algorithm layout and analytical properties for the ideal case are investigated. In comparison with the traditional cell-averaging (CA) CFAR and order-statistic (OS) CFAR, it is demonstrated that CI-CFAR outperforms both in most situations.
Autors: Kim, Jeong Hun;Bell, Mark R.;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Jul 2013, volume: 49, issue:3, pages: 1519 - 1535
Publisher: IEEE
 
» A dark-field microscope for background-free detection of resonance fluorescence from single semiconductor quantum dots operating in a set-and-forget mode
Abstract:
Optically active quantum dots, for instance self-assembled InGaAs quantum dots, are potentially excellent single photon sources. The fidelity of the single photons is much improved using resonant rather than non-resonant excitation. With resonant excitation, the challenge is to distinguish between resonance fluorescence and scattered laser light. We have met this challenge by creating a polarization-based dark-field microscope to measure the resonance fluorescence from a single quantum dot at low temperature. We achieve a suppression of the scattered laser exceeding a factor of 107 and background-free detection of resonance fluorescence. The same optical setup operates over the entire quantum dot emission range (920–980 nm) and also in high magnetic fields. The major development is the outstanding long-term stability: once the dark-field point has been established, the microscope operates for days without alignment. The mechanical and optical designs of the microscope are presented, as well as exemplary resonance fluorescence spectroscopy results on individual quantum dots to underline the microscope's excellent performance.
Autors: Kuhlmann, Andreas V.;Houel, Julien;Brunner, Daniel;Ludwig, Arne;Reuter, Dirk;Wieck, Andreas D.;Warburton, Richard J.;
Appeared in: Review of Scientific Instruments
Publication date: Jul 2013, volume: 84, issue:7, pages: 073905 - 073905-7
Publisher: IEEE
 
» A Data-Level Fusion Model for Developing Composite Health Indices for Degradation Modeling and Prognostic Analysis
Abstract:
Prognostics involves the effective utilization of condition or performance-based sensor signals to accurately estimate the remaining lifetime of partially degraded systems and components. The rapid development of sensor technology, has led to the use of multiple sensors to monitor the condition of an engineering system. It is therefore important to develop methodologies capable of integrating data from multiple sensors with the goal of improving the accuracy of predicting remaining lifetime. Although numerous efforts have focused on developing feature-level and decision-level fusion methodologies for prognostics, little research has targeted the development of “data-level” fusion models. In this paper, we present a methodology for constructing a composite health index for characterizing the performance of a system through the fusion of multiple degradation-based sensor data. This methodology includes data selection, data processing, and data fusion steps that lead to an improved degradation-based prognostic model. Our goal is that the composite health index provides a much better characterization of the condition of a system compared to relying solely on data from an individual sensor. Our methodology was evaluated through a case study involving a degradation dataset of an aircraft gas turbine engine that was generated by the Commercial Modular Aero-Propulsion System Simulation (C-MAPSS).
Autors: Liu, K.;Gebraeel, N.Z.;Shi, J.;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Jul 2013, volume: 10, issue:3, pages: 652 - 664
Publisher: IEEE
 
» A Describing Function Study of Saturated Quantization and Its Application to the Stability Analysis of Multi-Bit Sigma Delta Modulators
Abstract:
Just as their single-bit counterparts, multi-bit sigma delta modulators exhibit nonlinear behavior due to the presence of the quantizer in the loop. In the multi-bit case this is caused by the fact that any quantizer has a limited output range and hence gives an implicit saturation effect. Due to this, any multi-bit modulator is prone to modulator overloading. Unfortunately, until now, designers had to rely on extensive time-domain simulations to predict the overloading level, because there is no adequate analytical theory to model this effect.
Autors: Rombouts, P.;De Bock, M.;De Maeyer, J.;Weyten, L.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jul 2013, volume: 60, issue:7, pages: 1740 - 1752
Publisher: IEEE
 
» A Deterministic-Solution Based Fast Eigenvalue Solver With Guaranteed Convergence for Finite-Element Based 3-D Electromagnetic Analysis
Abstract:
A fast solution to both the quadratic eigenvalue problem and the generalized eigenvalue problem is developed for the finite-element based analysis of general 3-D electromagnetic problems. Given an arbitrary frequency band of interest, denoting the number of physically important eigenvalues for this band by , the proposed eigenvalue solution is capable of solving a significantly reduced eigenvalue problem of to find a complete set of eigenvalues and eigenvectors that are physically important for the given frequency band. In addition to bypassing the need of solving a large-scale eigenvalue problem of , with being the system matrix size, the reduced eigenvalue problem is constructed from solutions to a deterministic problem. As a result, the methods that have been developed to solve deterministic problems and their fast solvers can all be readily leveraged to solve eigenvalue problems. Moreover, the proposed fast eigenvalue solution has guaranteed convergence and controlled accuracy, which is theoretically proved in this paper. The solution is applicable to general 3-D problems where the structures are arbitrary, materials are inhomogeneous, and both dielectrics and conductors can be lossy. Applications to microwave devices, package structures, and on-chip integrated circuits have demonstrated the accuracy, efficiency, and convergence of the proposed fast eigenvalue solution.
Autors: Sheng, F.;Jiao, D.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jul 2013, volume: 61, issue:7, pages: 3701 - 3711
Publisher: IEEE
 
» A DFE Receiver With Equalized VREF for Multidrop Single-Ended Signaling
Abstract:
In this brief, decision-feedback equalization (DFE) receiver for multidrop single-ended signaling is described. The proposed DFE receiver adopts a reference voltage having equalization information to remove channel intersymbol interference. It uses a smaller number of DFE tap elements than the conventional DFE receiver for the same level of equalization, resulting in reduced power consumption and silicon area, particularly for multi-input/output interface. The proposed DFE receiver was fabricated in a 0.13- CMOS process, whose evaluation results indicate a reliable operation up to 3.40-Gb/s data rate with reduced power consumption.
Autors: Shin, W.-H.;Jun, Y.-H.;Kong, B.-S.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jul 2013, volume: 60, issue:7, pages: 412 - 416
Publisher: IEEE
 
» A Dictionary Learning Approach for Poisson Image Deblurring
Abstract:
The restoration of images corrupted by blur and Poisson noise is a key issue in medical and biological image processing. While most existing methods are based on variational models, generally derived from a maximum a posteriori (MAP) formulation, recently sparse representations of images have shown to be efficient approaches for image recovery. Following this idea, we propose in this paper a model containing three terms: a patch-based sparse representation prior over a learned dictionary, the pixel-based total variation regularization term and a data-fidelity term capturing the statistics of Poisson noise. The resulting optimization problem can be solved by an alternating minimization technique combined with variable splitting. Extensive experimental results suggest that in terms of visual quality, peak signal-to-noise ratio value and the method noise, the proposed algorithm outperforms state-of-the-art methods.
Autors: Ma, L.;Moisan, L.;Yu, J.;Zeng, T.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jul 2013, volume: 32, issue:7, pages: 1277 - 1289
Publisher: IEEE
 
» A dielectric-barrier discharge enhanced plasma brush array at atmospheric pressure
Abstract:
This study developed a large volume cold atmospheric plasma brush array, which was enhanced by a dielectric barrier discharge by integrating a pair of DC glow discharge in parallel. A platinum sheet electrode was placed in the middle of the discharge chamber, which effectively reduced the breakdown voltage and working voltage. Emission spectroscopy diagnosis indicated that many excited argon atoms were distributed almost symmetrically in the lateral direction of the plasma. The concentration variations of reactive species relative to the gas flow rate and discharge current were also examined.
Autors: Li, Xuemei;Tang, Jie;Zhan, Xuefang;Yuan, Xin;Zhao, Zhongjun;Yan, Yanyue;Duan, Yixiang;
Appeared in: Applied Physics Letters
Publication date: Jul 2013, volume: 103, issue:3, pages: 033519 - 033519-5
Publisher: IEEE
 
» A Digital Fractional-N PLL With a PVT and Mismatch Insensitive TDC Utilizing Equivalent Time Sampling Technique
Abstract:
A 6-bit time-to-digital converter that achieves mismatch free operation by using a single delay cell and sampling flip-flop is presented. The proposed TDC was integrated in a digital fractional-N PLL fabricated in a 32-nm digital SoC CMOS process for WiFi/WiMax radios. The TDC consumes 3 mW from a 1.05-V supply and occupies an area of 0.004 . A digital frequency-locked loop is used to track and correct for PVT variations in the TDC and no additional linearization or mismatch calibrations are required. The DPLL uses a 20-bit high dynamic range DAC to drive a VCO in order to effectively realize a DCO with 100-Hz frequency resolution. The 2.5-GHz WiFi band LO output is generated from a 40-MHz reference with an integrated phase noise of (10 kHz to 10 MHz) while consuming 21 mW . The worst case spur in the LO output is below without requiring TDC mismatch and linearity calibration.
Autors: Kim, H.S.;Ornelas, C.;Chandrashekar, K.;Shi, D.;Su, P.-E.;Madoglio, P.;Li, W.Y.;Ravi;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2013, volume: 48, issue:7, pages: 1721 - 1729
Publisher: IEEE
 
» A Discontinuous Galerkin Surface Integral Equation Method for Electromagnetic Wave Scattering From Nonpenetrable Targets
Abstract:
We present a discontinuous Galerkin surface integral equation method, herein referred to as IEDG, for time harmonic electromagnetic wave scattering from nonpenetrable targets. The proposed IEDG algorithm allows the implementation of the combined field integral equation (CFIE) using square-integrable, , trial and test functions without any considerations of continuity requirements across element boundaries. Due to the local characteristics of basis functions, it is possible to employ nonconformal surface discretizations of the targets. Furthermore, it enables the possibility to mix different types of elements and employ different order of basis functions within the same discretization. Therefore, the proposed IEDG method is highly flexible to apply adaptation techniques. Numerical results are included to validate the accuracy and demonstrate the versatility of the proposed IEDG method. In addition, a complex large-scale simulation is conducted to illustrate the potential benefits offered by the proposed method for modeling multiscale electrically large targets.
Autors: Peng, Z.;Lim, K.-H.;Lee, J.-F.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jul 2013, volume: 61, issue:7, pages: 3617 - 3628
Publisher: IEEE
 
» A Distributed Time Synchronization Solution without Satellite Time Reference for Mobile Communication
Abstract:
Synchronization is one of the most important issues for telecommunication. Some 3G and LTE mobile communication systems require high-accuracy time synchronization between neighboring base stations. Existing synchronization solutions rely heavily on the satellite time service system, such as GPS, as the common time reference. In the event that satellite systems become unavailable, time synchronization in a wide area would be lost. In this paper, a distributed time synchronization solution is proposed without relying on satellite time reference. Simulation and experimental results show that the proposed solution converges fast and can realize high-accuracy time synchronization for large-scale networks.
Autors: Han, Liuyan;Hua, Nan;
Appeared in: IEEE Communications Letters
Publication date: Jul 2013, volume: 17, issue:7, pages: 1447 - 1450
Publisher: IEEE
 
» A Divide-by-3 0.4–1.4 GHz Injection-Locked Frequency Divider Based on Relaxation Oscillator
Abstract:
In this letter, a new topology for divide-by-3 injection-locked frequency divider based on relaxation oscillator is reported. A prototype is designed and implemented in a 90 nm CMOS process technology. The measurement results demonstrate a locking range of 0.4–1.4 GHz with a power consumption of 30 .
Autors: Zhu, K.;Islam, S.K.;Roknsharifi, M.;Hasan, M.S.;Mahbub, I.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jul 2013, volume: 23, issue:7, pages: 368 - 370
Publisher: IEEE
 
» A Dual Band Leaky Wave Antenna on a CRLH Substrate Integrated Waveguide
Abstract:
This communication presents the results of an investigation of a new version of a leaky wave antenna designed on a CRLH substrate integrated waveguide. The antenna operates in two frequency bands and its main beam can be steered from backward to forward direction by changing the frequency. The antenna structure is planar and can be fabricated by a standard PCB technology, so it is suitable for mass production. An efficient method for determining the complex dispersion characteristic of periodic 1D structure is proposed.
Autors: Machac, J.;Polivka, M.;Zemlyakov, K.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jul 2013, volume: 61, issue:7, pages: 3876 - 3879
Publisher: IEEE
 
» A Fast and Accurate Feature-Matching Algorithm for Minimally-Invasive Endoscopic Images
Abstract:
The ability to find image similarities between two distinct endoscopic views is known as feature matching, and is essential in many robotic-assisted minimally-invasive surgery (MIS) applications. Differently from feature-tracking methods, feature matching does not make any restrictive assumption about the chronological order between the two images or about the organ motion, but first obtains a set of appearance-based image matches, and subsequently removes possible outliers based on geometric constraints. As a consequence, feature-matching algorithms can be used to recover the position of any image feature after unexpected camera events, such as complete occlusions, sudden endoscopic-camera retraction, or strong illumination changes. We introduce the hierarchical multi-affine (HMA) algorithm, which improves over existing feature-matching methods because of the larger number of image correspondences, the increased speed, and the higher accuracy and robustness. We tested HMA over a large (and annotated) dataset with more than 100 MIS image pairs obtained from real interventions, and containing many of the aforementioned sudden events. In all of these cases, HMA outperforms the existing state-of-the-art methods in terms of speed, accuracy, and robustness. In addition, HMA and the image database are made freely available on the internet.
Autors: Puerto-Souza, G.A.;Mariottini, G.L.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jul 2013, volume: 32, issue:7, pages: 1201 - 1214
Publisher: IEEE
 
» A Fast and Energy Efficient Single-Chip Touch Controller for Tablet Touch Applications
Abstract:
In tablet touch applications, fast sensing is essential to enhance reporting rate and low power consumption is also essential to prolong battery life. To satisfy both essential demands, a fast and energy efficient single-chip touch controller for medium size (7 to 11.6 inch) of capacitive touch screen panels (TSP) is presented. The presented touch controller is designed with fast sensing methods which are proposed to enhance reporting rate and to reduce power consumption. In this paper, the proposed fast sensing methods are described in detail with their implementation and experimental results. The presented touch controller consumes power of 47.50 mA at 10.1 inch TSP, providing the minimum reporting rate of 129 Hz under 10 simultaneous touches.
Autors: Lim, K.;Jung, K.-S.;Jang, C.-S.;Baek, J.-S.;Kang, I.-B.;
Appeared in: Journal of Display Technology
Publication date: Jul 2013, volume: 9, issue:7, pages: 520 - 526
Publisher: IEEE
 
» A Fast CT and CT-Fluoroscopy Registration Algorithm With Respiratory Motion Compensation for Image-Guided Lung Intervention
Abstract:
CT-fluoroscopy (CTF) is an efficient imaging technique for guiding percutaneous lung intervention such as biopsy and ablation. In CTF-guided procedures, four to ten axial images are captured in a very short time period during breath holding to provide near real-time feedback of patients’ anatomy so that physicians can adjust the needle as it is advanced toward a target lesion. Although popularly used in clinics, this procedure requires frequent scans to guide the needle, which may cause increased procedure time, complication rates, and radiation exposure to both clinicians and patients. In addition, CTF only generates a limited number of 2-D axial images and does not provide sufficient 3-D anatomical information. Therefore, how to provide volumetric anatomical information using CTF while reducing intraoperative scan is an important and challenging problem. In this paper, we propose a fast CT–CTF deformable registration algorithm that warps the inhale preprocedural CT onto the intraprocedural CTF for guidance in 3-D. In the algorithm, the deformation in the transverse plane is modeled using 2-D B-Spline, and the deformation along -direction is regularized by smoothness constraint. A respiratory motion compensation framework is also incorporated for accurate registration. A parallel implementation strategy is adopted to accomplish the registration in several seconds. With electromagnetic tracking, the needle position can be superimposed onto the deformed inhale CT image, thereby providing 3-D image guidance during breath holding. Experiments were conducted using both simulated CTF images with known deformation and real CTF images captured during lung cancer biopsy studies. The experiments demonstrated satisfactory registration results of our proposed fast CT–CTF registration algorithm.
Autors: Su, P.;Yang, J.;Lu, K.;Yu, N.;Wong, S.T.;Xue, Z.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jul 2013, volume: 60, issue:7, pages: 2034 - 2041
Publisher: IEEE
 
» A Fast Evolutionary Algorithm for Real-Time Vehicle Detection
Abstract:
The evolutionary algorithm (EA) is an effective method for solving various problems because it can search through very large search spaces and can quickly come to nearly optimal solutions. However, existing EA-based methods for vehicle detection cannot achieve high performance because their fitness functions depend on sensitive information, such as edge or color information on the preceding vehicle. This paper focuses on improving the performance of existing evolutionary-based methods for vehicle detection by introducing an effective fitness function that can more accurately capture a vehicle's information by combining a disparity map, edge information, and the position and motion of the preceding vehicle. The proposed method can detect multiple vehicles by using a turn-back genetic algorithm (GA) and can prevent false detection by using motion detection. Our fitness function is designed in a typical manner along with the fitness parameters. These parameters are usually selected using heuristic methods, making the choice of optimal parameters difficult. Therefore, this paper proposes a new approach to estimating optimal fitness parameters using EA and the least squares method. Robustness testing showed that the proposed method provides detection rate (DR) results close to those obtained using a state-of-the-art system and outperforms other dominant vehicle-detection-based EAs.
Autors: Nguyen, V.D.;Nguyen, T.T.;Nguyen, D.D.;Lee, S.J.;Jeon, J.W.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2013, volume: 62, issue:6, pages: 2453 - 2468
Publisher: IEEE
 
» A Fast Hybrid ε-Approximation Algorithm for Computing Constrained Shortest Paths
Abstract:
Considerable efforts have been dedicated to develop both heuristic and approximation algorithms for the NP-complete delay-constrained least-cost (DCLC) routing problem, but to the best of our knowledge, no prior work has been done to mingle the two tracks of research. In this letter we introduce a novel idea to show how a heuristic method can be used to boost the average performance of an approximation algorithm. Simulations on networks of up to 8192 nodes demonstrate that our new hybrid ε-approximation algorithm is faster than the best known approximation algorithm by one or two orders of magnitude (depending on the network size and ε).
Autors: Feng, Gang;Korkmaz, Turgay;
Appeared in: IEEE Communications Letters
Publication date: Jul 2013, volume: 17, issue:7, pages: 1471 - 1474
Publisher: IEEE
 
» A Fast Rendezvous Channel-Hopping Algorithm for Cognitive Radio Networks
Abstract:
Cognitive radio networks (CRNs) have emerged as a critical technique to enhance the utilization of licensed channels. In CRNs, each secondary user (SU) should not interfere the co-locate incumbent networks. For this purpose, before data transmission, SUs should rendezvous on an available channel (i.e., idle and licensed channel) for establishing a link or exchanging control information. However, implementation of rendezvous is challenging since SUs are not aware of the presence of each other before rendezvous and available channels sensed by each SU may be different. In this paper, we proposed a fast rendezvous channel hopping algorithm (FRCH), which can guarantee rendezvous within 2N^2+N timeslots under asynchronous environments, where N denotes the number of licensed channels in a CRN.
Autors: Chang, Guey-Yun;Huang, Jen-Feng;
Appeared in: IEEE Communications Letters
Publication date: Jul 2013, volume: 17, issue:7, pages: 1475 - 1478
Publisher: IEEE
 
» A Flexible Concept for Designing Multiaxis Force/Torque Sensors Using Force Closure Theorem
Abstract:
Multiaxis force/torque sensors have many applications in the areas of robotics and automation. A building blocks concept to design multiaxis force/torque sensors is introduced to provide a flexible and low-cost solution to measure multidimensional force/torque signals using a modularized assembly of several off-the-shelf 1-D force sensors. Based on the force closure theorem, we first identify the relationship between the required number of the 1-D force sensors and the dimensions of the measured force/torque signal. Furthermore, we formulate alternatives of the design solution for a multiaxis force/torque sensor, including the location and direction of each 1-D sensor. A virtual prototype of a six-axis force/torque is developed using this concept. Matrix-based force measuring models are derived to compute the six-axis force/torque signals from the output signals of seven 1-D force sensors. The matrix-based force measuring equations are validated using automatic dynamic analysis of mechanical systems. The output signals of the six-axis force/torque signal is consistent with the reference signals measured by an ATI Nano-17 force/torque sensor. One major advantage of this design concept is its flexibility; we can easily adapt the mechanical structure to design multidimensional force/torque sensors ranging from two degrees of freedom (2-DOFs) to 6-DOFs.
Autors: Dangxiao Wang;Jing Guo;Chuangchuang Sun;Mu Xu;Yuru Zhang;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jul 2013, volume: 62, issue:7, pages: 1951 - 1959
Publisher: IEEE
 
» A Flux Focusing Axial Magnetic Gear
Abstract:
This paper investigates a novel axial magnetic gear using ferrite magnets. In order to increase the air-gap flux density the ferrite magnets are arranged in flux focusing configuration. The simulation results presented in this paper indicate that a relatively high torque density can be achieved when using only ferrite magnets.
Autors: Acharya, V.M.;Bird, J.Z.;Calvin, M.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2013, volume: 49, issue:7, pages: 4092 - 4095
Publisher: IEEE
 
» A Framework for Investigating the Performance of Chaotic-Map Truly Random Number Generators
Abstract:
This brief approximates the hidden Markov model of chaotic-map truly random number generators (TRNGs) and describes its fundamental limits based on the approximate entropy rate of the underlying bit-generation process. It is demonstrated that the entropy rate plays a key role in the performance and robustness of chaotic-map TRNGs, which must be taken into account in the circuit design optimization. Finally, the optimality conditions for postprocessing units that extract truly random bits from a raw random number generator are derived.
Autors: Beirami, A.;Nejati, H.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jul 2013, volume: 60, issue:7, pages: 446 - 450
Publisher: IEEE
 
» A Framework for the Integrated Optimization of Charging and Power Management in Plug-in Hybrid Electric Vehicles
Abstract:
This paper develops a dynamic programming (DP)-based framework for simultaneously optimizing the charging and power management of a plug-in hybrid electric vehicle (PHEV). These two optimal control problems relate to activities of the PHEV on the electric grid (i.e., charging) and on the road (i.e., power management). The proposed framework solves these two problems simultaneously to avoid loss of optimality resulting from solving them separately. The framework furnishes optimal trajectories of PHEV states and control inputs over a 24-h period. We demonstrate the framework for 24-h scenarios with two driving trips and different power grid generation mixes. The results show that addressing the aforementioned optimization problems simultaneously can elucidate valuable insights. For example, for the chosen daily driving scenario, grid generation mixes, and optimization objective, it is shown that it is not always optimal to completely charge a battery before each driving trip. In addition, reduction in resulting from the synergistic interaction of PHEVs with an electric grid containing a significant amount of wind power is studied. The main contribution of this paper to the literature is a framework that makes it possible to evaluate tradeoffs between charging and on-road power management decisions.
Autors: Patil, R.M.;Kelly, J.C.;Filipi, Z.;Fathy, H.K.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2013, volume: 62, issue:6, pages: 2402 - 2412
Publisher: IEEE
 
» A Frequency-Domain LOS Angle-of-Arrival Estimation Approach in Multipath Channels
Abstract:
In this paper, we deal with the line-of-sight angle of arrival (AoA) estimation in a multipath channel, assuming that the first arrival path (FAP) contains the AoA information. We consider pulse transmission with a low duty cycle from the source and reception using an antenna array. We propose a simple approach that comprises the following four steps: 1) coarse frame synchronization; 2) frequency-domain channel estimation; 3) frequency-domain identification of the FAP delay with a threshold-based method; and 4) AoA estimation from the FAP coefficient. We compare the method with the joint angle and delay estimation multiple-signal classification (JADE MUSIC) algorithm. Despite the high complexity of the JADE MUSIC, our approach exhibits smaller root-mean-square error (RMSE) in the AoA estimation for various multipath channel scenarios that are characterized by different values of delay spread and angular spread correlation.
Autors: Inserra, D.;Tonello, A.M.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2013, volume: 62, issue:6, pages: 2812 - 2818
Publisher: IEEE
 
» A Fully Integrated Ka-Band VSAT Down-Converter
Abstract:
A fully integrated Ka-band down-converter for VSAT applications will be demonstrated. The high-band (21.4–22.0 GHz) and the low-band (19.2–20.2 GHz) are simultaneously down converted to the L-band (950–2150 MHz) and independently accessible by two users. The SSB-NF is better than 8 dB at a conversion gain of 25 dB (20 dB) for the low-band (high-band). The integrated PLL achieves a state-of-the-art integrated phase noise of 1.2 rms. The total solution consumes 548 mW.
Autors: de Jong, G.W.;Leenaerts, D.M.W.;van der Heijden, E.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2013, volume: 48, issue:7, pages: 1651 - 1658
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: Jul 2013, volume: 49, issue:4, pages: 1711 - 1719
Publisher: IEEE
 
» A Generalized Closed Form Expression of Directivity of Arbitrary Planar Antenna Arrays
Abstract:
A generalized unique expression for directivity of arbitrary planar antenna arrays having , element pattern is derived. Parameters of the new equation, other than the source type, are operating frequency, location, excitation amplitude and excitation phase of each individual element on that structure. Simplicity and compactness of this equation saves the runtime, memory requirement and computer costs. Examples on three array sets have been given to illustrate the effectiveness of this expression. Result of each example is compared with that of referred work, or a standard numerical method to show the computational efficiency.
Autors: Das, S.;Mandal, D.;Kar, R.;Ghoshal, S.P.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jul 2013, volume: 61, issue:7, pages: 3909 - 3911
Publisher: IEEE
 
» A High Efficiency Orthogonally Switching Passive Charge Pump Rectifier for Energy Harvesters
Abstract:
The design and analytical modeling of a high efficiency energy harvester comprising a passive voltage-boosting network (VBN) and a switching charge pump rectifier (CPR) is presented in this paper. To improve the power conversion efficiency (PCE), the VBN increases the voltage at the input of the CPR and provides control signals for switching. Unlike traditional Schottky and diode-connected MOS transistor rectifiers, the proposed orthogonally switching CPR (OS-CPR) comprises MOS transistors as voltage-controlled switches. Analytical models for the OS-CPR are developed and presented. Circuit-level optimization techniques are employed to reduce conduction and switching losses. Simulated in a 90 nm standard CMOS technology (IBM 9RF), a 5-stage 915 MHz OS-CPR achieves a dc voltage of 1.35 V and a PCE of 11.9% with a 1 M load at dBm available input power . To show technology scalability of the design, the OS-CPR is also validated using AMS 0.18 m high-voltage (HV) CMOS technology. When benchmarked with traditional rectifiers, the OS-CPR (under similar conditions) achieves a higher PCE and a higher output dc voltage. The OS-CPR is easily scalable to operate over multiple sub-GHz ISM frequency bands.
Autors: Mansano, A.;Bagga, S.;Serdijn, W.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jul 2013, volume: 60, issue:7, pages: 1959 - 1966
Publisher: IEEE
 
» A High Order Numerical Investigation of Electromagnetic Scattering From a Torus and a Circular Loop
Abstract:
The normally integrated magnetic field integral equation (NIMFIE) formulation is used to generate accurate numerical results for toroidal scatterers. Numerical data for the surface currents and scattering cross section induced by a plane wave on a perfectly conducting torus are presented. The special case of a thin circular loop is also examined. These results are expected to find use in numerical validation.
Autors: Bibby, M.M.;Coldwell, C.M.;Peterson, A.F.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jul 2013, volume: 61, issue:7, pages: 3656 - 3661
Publisher: IEEE
 
» A High Performing Memetic Algorithm for the Flowshop Scheduling Problem With Blocking
Abstract:
This paper considers minimizing makespan for a blocking flowshop scheduling problem, which has important application in a variety of modern industries. A constructive heuristic is first presented to generate a good initial solution by combining the existing profile fitting (PF) approach and Nawaz–Enscore–Ham (NEH) heuristic in an effective way. Then, a memetic algorithm (MA) is proposed including effective techniques like a heuristic-based initialization, a path-relinking-based crossover operator, a referenced local search, and a procedure to control the diversity of the population. Afterwards, the parameters and operators of the proposed MA are calibrated by means of a design of experiments approach. Finally, a comparative evaluation is carried out with the best performing algorithms presented for the blocking flowshop with makespan criterion, and with the adaptations of other state-of-the-art MAs originally designed for the regular flowshop problem. The results show that the proposed MA performs much better than the other algorithms. Ultimately, 75 out of 120 upper bounds provided by Ribas [“An iterated greedy algorithm for the flowshop scheduling with blocking”, OMEGA, vol. 39, pp. 293–301, 2011.] for Taillard flowshop benchmarks that are considered as blocking flowshop instances are further improved by the presented MA.
Autors: Pan, Q.;Wang, L.;Sang, H.;Li, J.;Liu, M.;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Jul 2013, volume: 10, issue:3, pages: 741 - 756
Publisher: IEEE
 
» A High-Efficiency Nonuniform Grating Coupler Realized With 248-nm Optical Lithography
Abstract:
We describe a high-efficiency grating coupler (GC) fabricated on a silicon-on-insulator wafer with 220 nm top silicon layer. One single 60 nm shallow etch is required to define the diffractive gratings with a minimum lithographic feature size of 180 nm, which is within the limitation of 248 nm deep ultraviolet lithography. The measured average insertion loss is with a 1 dB bandwidth of for TE polarization, whereas the best device exhibits 2.7 dB loss. The measured GC backreflection loss is better than 17 dB across the wafer. Cross-wafer data shows good uniformity and tolerance to fabrication variations. This is the best result reported for the commonly used 220 nm thickness Si that uses only a shallow etch step.
Autors: He, L.;Liu, Y.;Galland, C.;Lim, A.E.-J.;Lo, G.-Q.;Baehr-Jones, T.;Hochberg, M.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jul 2013, volume: 25, issue:14, pages: 1358 - 1361
Publisher: IEEE
 
» A high-flux high-order harmonic source
Abstract:
We develop and implement an experimental strategy for the generation of high-energy high-order harmonics (HHG) in gases for studies of nonlinear processes in the soft x-ray region. We generate high-order harmonics by focusing a high energy Ti:Sapphire laser into a gas cell filled with argon or neon. The energy per pulse is optimized by an automated control of the multiple parameters that influence the generation process. This optimization procedure allows us to obtain energies per pulse and harmonic order as high as 200 nJ in argon and 20 nJ in neon, with good spatial properties, using a loose focusing geometry (f#≈400) and a 20 mm long medium. We also theoretically examine the macroscopic conditions for absorption-limited conversion efficiency and optimization of the HHG pulse energy for high-energy laser systems.
Autors: Rudawski, P.;Heyl, C.M.;Brizuela, F.;Schwenke, J.;Persson, A.;Mansten, E.;Rakowski, R.;Rading, L.;Campi, F.;Kim, B.;Johnsson, P.;LHuillier, A.;
Appeared in: Review of Scientific Instruments
Publication date: Jul 2013, volume: 84, issue:7, pages: 073103 - 073103-7
Publisher: IEEE
 
» A high-order harmonic generation apparatus for time- and angle-resolved photoelectron spectroscopy
Abstract:
We present a table top setup for time- and angle-resolved photoelectron spectroscopy to investigate band structure dynamics of correlated materials driven far from equilibrium by femtosecond laser pulse excitation. With the electron-phonon equilibration time being in the order of 1–2 ps it is necessary to achieve sub-picosecond time resolution. Few techniques provide both the necessary time and energy resolution to map non-equilibrium states of the band structure. Laser-driven high-order harmonic generation is such a technique. In our experiment, a grating monochromator delivers tunable photon energies up to 40 eV. A photon energy bandwidth of 150 meV and a pulse duration of 100 fs FWHM allow us to cover the k-space necessary to map valence bands at different kz and detect outer core states.
Autors: Frietsch, B.;Carley, R.;Dobrich, K.;Gahl, C.;Teichmann, M.;Schwarzkopf, O.;Wernet, Ph.;Weinelt, M.;
Appeared in: Review of Scientific Instruments
Publication date: Jul 2013, volume: 84, issue:7, pages: 075106 - 075106-10
Publisher: IEEE
 
» A highly efficient and compact long pulse Nd:YAG rod laser with 540 J of pulse energy for welding application
Abstract:
We have developed an efficient and high average power flash lamp pumped long pulse Nd:YAG laser capable of generating 1 kW of average output power with maximum 540 J of single pulse energy and 20 kW of peak power. The laser pulse duration can be varied from 1 to 40 ms and repetition rate from 1 to 100 Hz. A compact and robust laser pump chamber and resonator was designed to achieve this high average and peak power. It was found that this laser system provides highest single pulse energy as compared to other long pulsed Nd:YAG laser systems of similar rating. A slope efficiency of 5.4% has been achieved, which is on higher side for typical lamp pumped solid-state lasers. This system will be highly useful in laser welding of materials such as aluminium and titanium. We have achieved 4 mm deep penetration welding of these metals under optimized conditions of output power, pulse energy, and pulse duration. The laser resonator was optimized to provide stable operation from single shot to 100 Hz of repetition rate. The beam quality factor was measured to be M2 ∼ 91 and pulse-to-pulse stability of ±3% for the multimode operation. The laser beam was efficiently coupled through an optical fiber of 600 μm core diameter and 0.22 numerical aperture with power transmission of 90%.
Autors: Choubey, Ambar;Vishwakarma, S.C.;Misra, Pushkar;Jain, R.K.;Agrawal, D.K.;Arya, R.;Upadhyaya, B.N.;Oak, S.M.;
Appeared in: Review of Scientific Instruments
Publication date: Jul 2013, volume: 84, issue:7, pages: 073108 - 073108-8
Publisher: IEEE
 
» A Histogram-Based Segmentation Method for Wideband Spectrum Sensing in Cognitive Radios
Abstract:
This paper presents a new method for automatic radio spectrum segmentation. Spectrum segmentation serves as a first step to identify the subbands that are in use at a certain time, when a wide portion of the spectrum is observed. The proposed method, based on the evaluation of the histogram of the power spectral density of the received signal, is designed for obtaining a low processing complexity and to be implemented in a measurement instrument or a cognitive radio receiver. The proposed method is validated on emulated signals, and the results show good accuracy of the subband boundary estimation and a processing complexity much lower than the other segmentation methods.
Autors: Bao, D.;De Vito, L.;Rapuano, S.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jul 2013, volume: 62, issue:7, pages: 1900 - 1908
Publisher: IEEE
 
» A Hybrid Modular Multilevel Voltage Source Converter for HVDC Power Transmission
Abstract:
HVDC transmission systems are becoming increasingly popular when compared to conventional ac transmission. HVDC voltage source converters (VSCs) can offer advantages over traditional HVDC current source converter topologies, and as such, it is expected that HVDC VSCs will be further exploited with the growth of HVDC transmission. This paper presents a novel modular multilevel converter hybrid VSC intended for the HVDC market. The concept of the converter operation is described based on steady-state ac–dc power balance. Techniques for dynamic voltage control, enabling the active and reactive powers exchanged with the grid to be controlled, are introduced. Simulation results further illustrate the theory of operation of the converter and confirm the viability of the proposed control approaches. Detailed predictions of the semiconductor losses confirm the potential to achieve very high efficiencies with this topology. Experimental results are provided to validate the presented converter operation.
Autors: Feldman, R.;Tomasini, M.;Amankwah, E.;Clare, J.C.;Wheeler, P.W.;Trainer, D.R.;Whitehouse, R.S.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jul 2013, volume: 49, issue:4, pages: 1577 - 1588
Publisher: IEEE
 
» A Hybrid System of Li-Ion Capacitors and Flow Battery for Dynamic Wind Energy Support
Abstract:
Wind farm output power fluctuations create adverse effects on the voltage, frequency, and transient stability of the utility grid. Short-term wind farm power variations with high ramp rates can cause voltage instabilities, particularly if the farm is located in weak-grid areas. The integration of wind energy with energy storage devices to support the short-term shortcomings of wind energy is discussed in this paper. A turbine level hybrid configuration of an energy storage system is used to limit the power ramp rates and apply power smoothing. The proposed energy storage devices are the zinc bromide flow battery and lithium-ion capacitors. The actual models for the battery and capacitors used in this study are derived from laboratory tests. The wind farm power is also modeled using measured wind speed data. A new concept has been introduced to evaluate the effectiveness of energy storage system for wind energy support. The analysis shows that significant improvements can be made to shape the output power of the farm using energy storage systems.
Autors: Esmaili, A.;Novakovic, Bora;Nasiri, A.;Abdel-Baqi, O.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jul 2013, volume: 49, issue:4, pages: 1649 - 1657
Publisher: IEEE
 
» A Largely Deformable Surface Type Neural Electrode Array Based on PDMS
Abstract:
This paper describes a largely deformable surface type neural electrode array based on polydimethylsiloxane (PDMS) for cortical use. Noncracked and reliable metal patterns were fabricated successfully on PDMS substrate by employing an intermediate parylene layer. The mechanical and electrical stability of the fabricated electrode arrays was demonstrated by repeatable bending test using a custom-designed bending test module. Also the adhesion of the electrode structure consisting of PDMS, parylene and metal layers was proven by ASTM tape test. The electrode impedance was measured in phosphate buffered saline (PBS) solution at 37 C over three months and analyzed using equivalent circuit models. Based on these results, it is concluded that the suggested electrode array provides a largely deformable structure with mechanical integrity and electrical stability, which can withstand mechanical stresses when inserted through a small trephination hole in the skull and expanded in the small room between the cortex and the skull without damage to the electrode array.
Autors: Chou, N.;Yoo, S.;Kim, S.;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Jul 2013, volume: 21, issue:4, pages: 544 - 553
Publisher: IEEE
 
» A Lifelong Fascination [Memoirs]
Abstract:
Autors: Nailen, R.;
Appeared in: IEEE Industry Applications Magazine
Publication date: Jul 2013, volume: 19, issue:4, pages: 88 - 88
Publisher: IEEE
 
» A Linear Programming Based Tone Injection Algorithm for PAPR Reduction of OFDM and Linearly Precoded Systems
Abstract:
This work investigates the improvement of power amplifier efficiency through the reduction of peak-to-average power ratio (PAPR) of linearly precoded QAM data signals. In particular, we focus on the special cases of linear precoded modulation including the practical OFDM, OFDMA, and SC-FDMA signals that have been widely adopted in W-LAN and W-MAN. We apply the method of tone injection optimization for PAPR reduction. To reduce numerical complexity, we propose a linear programming algorithm which closely approximates the original tone injection optimization problem. Our comprehensive numerical results demonstrate substantial PAPR reduction and superior BER performance using several practical examples.
Autors: Jacklin, N.;Ding, Z.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jul 2013, volume: 60, issue:7, pages: 1937 - 1945
Publisher: IEEE
 
» A Load–Pull Characterization Technique Accounting for Harmonic Tuning
Abstract:
A novel methodology for the characterization of the nonlinear dynamic behavior of electron devices (EDs) is presented. It is based on a complete and accurate ED characterization that is provided by large-signal low-frequency I/V measurements, performed by means of a low-cost setup, in conjunction with any model-based description of the nonlinear reactive effects related to ED capacitances. The unique feature of the proposed technique is that a fully harmonic control of waveforms at the current generator plane is achieved, and as a consequence, high-efficiency operation can be simply investigated. Different experimental data are presented on GaAs and GaN transistors, and to definitely verify the capability of the new approach, the design of a class-F GaN power amplifier is deeply investigated as a case study.
Autors: Vadala, V.;Raffo, A.;Di Falco, S.;Bosi, G.;Nalli, A.;Vannini, G.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jul 2013, volume: 61, issue:7, pages: 2695 - 2704
Publisher: IEEE
 
» A Low-Cost Power-Quality Meter With Series Arc-Fault Detection Capability for Smart Grid
Abstract:
This paper presents a low-cost digital single-phase power-quality measurement device for consumer use with a wide range of features, including series arc-fault detection, load trip on failure, and phase/neutral line wiring mix up indication. A wavelet multiresolution analysis technique was utilized for the voltage transient event detection and the current drop pattern recognition, specifically to arc fault. The last feature also involved the use of adaptive thresholding, peak detection, and repetition frequency calculation. A computationally efficient and accurate Goertzel filter was used for total harmonic distortion calculation. In addition, this meter can measure phase fundamental frequency (using the zero-crossing technique), rms values, and power. MATLAB and MathCAD packages were used to build and simulate arc-fault model and phase voltage distortion, to design and test part of the developed algorithms, which were further implemented in Embedded C and Assembler programming languages. A prototype circuit board with the required sensors and relay, analog isolation, indication, user controls, communication link, and a low-cost microchip microcontroller (MCU) dsPIC33 was designed and built to validate implemented algorithms and conduct experiments.
Autors: Koziy, K.;Gou, B.;Aslakson, J.;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Jul 2013, volume: 28, issue:3, pages: 1584 - 1591
Publisher: IEEE
 
» A low-frequency noise model with carrier generation-recombination process for pentacene organic thin-film transistor
Abstract:
By including the generation-recombination process of charge carriers in conduction channel, a model for low-frequency noise in pentacene organic thin-film transistors (OTFTs) is proposed. In this model, the slope and magnitude of power spectral density for low-frequency noise are related to the traps in the gate dielectric and accumulation layer of the OTFT for the first time. The model can well fit the measured low-frequency noise data of pentacene OTFTs with HfO2 or HfLaO gate dielectric, which validates this model, thus providing an estimate on the densities of traps in the gate dielectric and accumulation layer. It is revealed that the traps in the accumulation layer are much more than those in the gate dielectric, and so dominate the low-frequency noise of pentacene OTFTs.
Autors: Han, C.Y.;Qian, L.X.;Leung, C.H.;Che, C.M.;Lai, P.T.;
Appeared in: Journal of Applied Physics
Publication date: Jul 2013, volume: 114, issue:4, pages: 044503 - 044503-6
Publisher: IEEE
 
» A Low-Power Directional Gamma-Ray Sensor System for Long-Term Radiation Monitoring
Abstract:
A Low-power directional gamma-ray sensor system for long-term radiation monitoring is presented in this paper. The system can determine the direction of gamma-rays emitted from multiple point sources while simultaneously identifying them. The overall system is formed by merging a sensor section with a compact and low-power computational radiation sensor section. The sensor section houses three NaI gamma-ray detectors arranged in a spatial configuration that allows detection on a plane defined by the front faces of the detectors. The computational section is based on a single chip solution developed by the authors that house multiple low-power event-driven sensor front ends, event-driven analog-to-digital converters, and a dedicated microcontroller on the same silicon die. The presented system is capable of collecting individual gamma isotope detection events within the three separate NaI scintillator detectors. Further processing of the data to yield direction finding and multiple isotope identification is possible by executing software algorithms using the computation resources available on chip. To that end, a compact fixed-point program is developed to perform on-chip real-time gamma isotope identification and direction estimation. The single chip solution is fabricated in a 0.18- CMOS technology with field tests demonstrating the validity of the approaches taken. The total computational sensor system power consumption is less than 20 , excluding the detector power consumption. The gamma isotope identification and direction finding program executes in less than 100 ms. The system is validated by multiple 1- gamma-ray calibration button sources set at 25-cm distance from the detector setup. The system starts to provide consistent an- repeatable results with less than 5 errors in accuracy, once more than 2000 total photopeaks are gathered in a detection session. Since the underlying processing paradigm is event-driven and low-power, the possible field applications of the presented system involve long-term monitoring for radiation detection and protection, where low count rates may be present.
Autors: Schrage, C.;Schemm, N.;Balkir, S.;Hoffman, M.W.;Bauer, M.;
Appeared in: IEEE Sensors Journal
Publication date: Jul 2013, volume: 13, issue:7, pages: 2610 - 2618
Publisher: IEEE
 
» A Low-Power Processor With Configurable Embedded Machine-Learning Accelerators for High-Order and Adaptive Analysis of Medical-Sensor Signals
Abstract:
Low-power sensing technologies have emerged for acquiring physiologically indicative patient signals. However, to enable devices with high clinical value, a critical requirement is the ability to analyze the signals to extract specific medical information. Yet given the complexities of the underlying processes, signal analysis poses numerous challenges. Data-driven methods based on machine learning offer distinct solutions, but unfortunately the computations are not well supported by traditional DSP. This paper presents a custom processor that integrates a CPU with configurable accelerators for discriminative machine-learning functions. A support-vector-machine accelerator realizes various classification algorithms as well as various kernel functions and kernel formulations, enabling range of points within an accuracy-versus-energy and -memory trade space. An accelerator for embedded active learning enables prospective adaptation of the signal models by utilizing sensed data for patient-specific customization, while minimizing the effort from human experts. The prototype is implemented in 130-nm CMOS and operates from 1.2 V–0.55 V (0.7 V for SRAMs). Medical applications for EEG-based seizure detection and ECG-based cardiac-arrhythmia detection are demonstrated using clinical data, while consuming 273 J and 124 J per detection, respectively; this represents 62.4 and 144.7 energy reduction compared to an implementation based on the CPU. A patient-adaptive cardiac-arrhythmia detector is also demonstrated, reducing the analysis-effort required for model customization by 20 .
Autors: Lee, K.H.;Verma, N.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2013, volume: 48, issue:7, pages: 1625 - 1637
Publisher: IEEE
 

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