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Electrical and Electronics Engineering publications abstract of: 07-2011 sorted by title, page: 0
» "Global Comsoc" embracing the globe [The President's Page]
Abstract:
The ??Golden Triangle?? vision, as introduced in the January 2010 President??s Page, supports transformation of our IEEE Communications Society (ComSoc) into a truly global, vital and high-value professional society. The three vertices of the ??Golden Triangle,?? namely Globalization, Young Leaders, and Industry, are the three fundamental concepts of transformation. Globalization enables utilization of the best talent, education, training and cultural values among our members from around the world. Young Leaders are the future of our Society. Interestingly, the rapidly growing countries, fueling the drive for Globalization, have higher percentages of their work force under- 30 years of age. Industry implements technology in products and services, making these available to user communities around the world, including rurual areas and the expanding consumer base around the world. All three vertices in the ??Golden Triangle,?? therefore, center around Globalization in the development and operations of our Communications Society.
Autors: Lee, B.G.;Goyal, S.;Saracco, R.;Yamanaka, N.;Durrani, T.;Cely, J.D.;Jakobson, G.;
Appeared in: IEEE Communications Magazine
Publication date: Jul 2011, volume: 49, issue:7, pages: 6 - 10
Publisher: IEEE
 
» 100G in the network of Deutsche Telekom
Abstract:
 Highlights: ? DP-QPSK-CD format and DSP enable cost effective next generation Tb/s networks. ? Fiber impairments can be efficiently compensated by DSP in advanced receivers. ? A 100Gb/s DWDM transmission formats fit into existing fiber network infrastructure. ? Silicon photonics is a key technology in next generation higher speed interfaces.

Autors: The increased traffic demand in data centers and optical transport networks requires higher speed interfaces for the intra- and inter- connections between routers and switches. After 3years the 100Gb/s Ethernet (100GE) interface was standardized in t
Appeared in: Optical Fiber Technology
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» 100G optical transport based on polarization and/or subcarrier multiplexed modulation formats
Abstract:
 Highlights: ? A comprehensive paper and helpful guide on 100G modulation format optimizations. ? A presentation of extensive lab transmission and carrier trial results with some of the leading system performances. ? Expert discussion on practical implementation issues and trade-offs of 100G modulation formats.

Autors: Future optical transport systems at 100G and beyond will inevitably make use of advanced modulation formats and digital signal processing techniques. In this contribution, we discuss 100G techniques based on the combination of subcarrier multiplexing
Appeared in: Optical Fiber Technology
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» 100GbE and beyond for warehouse scale computing interconnects
Abstract:
 Highlights: ? As computation moves into the cloud, the computing platforms are no longer stand-alone servers but warehouse-scale computers. ? New internet applications such as cloud computing and CDN are now reshaping the network landscape. ? In warehouse scale computing infrastructure, interconnections are aggregated with hierarchies of switching fabrics. ? Intra-datacenter connections can take advantage of a fiber-rich physical layer. ? Fiber-scarce inter-datacenter connections will drive the adoption of 100GbE and beyond in the massive WSC environments.

Autors: Increasing broadband penetration in the last few years has resulted in a dramatic growth in innovative, bandwidth-intensive applications that have been embraced by the consumers. Coupled with this consumer trend is the migration from local compute/st
Appeared in: Optical Fiber Technology
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» 2011 IAS Annual Meeting [Education Department News]
Abstract:
Autors: Sottile, J.;
Appeared in: IEEE Industry Applications Magazine
Publication date: Jul 2011, volume: 17, issue:4, pages: 75 - 75
Publisher: IEEE
 
» 210-GHz InAlN/GaN HEMTs With Dielectric-Free Passivation
Abstract:
Lattice-matched depletion-mode InAlN/AlN/GaN high-electron mobility transistors (HEMTs) on a SiC substrate were fabricated, for the first time, with a dielectric-free passivation (DFP) process in which the device access region was treated by plasma. Similar to dielectric passivation using SiN and , the plasma treatment can effectively shorten the gate-length extension. As a result, the current gain cutoff frequency of a 60-nm rectangular-gate HEMT increased from 125 to 210 GHz after the plasma DFP; this RF performance is among the highest reported for GaN-based HEMTs. The device showed a dc drain current density of 2.1 A/mm and a peak extrinsic transconductance of 487 mS/mm after DFP. The product of 12.6 is among the highest reported for a gate-physical-length-to-barrier-thickness aspect ratio of 5.6. Small gate lag and drain lag are observed in pulsed measurements with a 300-ns pulsewidth.
Autors: Wang, R.;Li, G.;Laboutin, O.;Cao, Y.;Johnson, W.;Snider, G.;Fay, P.;Jena, D.;Xing, H.;
Appeared in: IEEE Electron Device Letters
Publication date: Jul 2011, volume: 32, issue:7, pages: 892 - 894
Publisher: IEEE
 
» 224-Gb/s POLMUX-RZ-16QAM for next generation high-capacity optical transmission systems
Abstract:
 Highlights: ? POLMUX-RZ-16QAM enables transmitting a data rate of 224Gb/s with a SE of 4.2b/s/Hz. ? The 224Gb/s signal has a penalty of 4.3dB in comparison to theoretical limit. ? Transmission of 11×224Gb/s over 1500km has been successfully demonstrated.

Autors: In this paper, we study the 224-Gb/s polarization multiplexed, return to zero, 16-level quadrature amplitude modulation (POLMUX-RZ-16QAM) as a candidate for next generation high capacity optical transmission systems. We discuss the main challenges as
Appeared in: Optical Fiber Technology
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» 2 25-kV 50 Hz High-Speed Traction Power System: Short-Circuit Modeling
Abstract:
A 2 25-kV 50 Hz traction power system was analyzed and modeled in the time domain in order to simulate short-circuit conditions and to attain a practical method to identify the short circuit behavior of the traction system. In particular, due to the difficulty in assessing the track-line parameters which mainly depend on changing environmental conditions, the possibility of neglecting the capacitive parameters was analyzed. A complete model of the 2 25-kV 50 Hz traction power system was developed and validated through comparison with the results of referenced models and experimental tests performed on real systems. Simulations, addressed to reduce the short-circuit modeling complexity, demonstrate that neglecting the capacitive effects between conductors and to ground does not affect the calculation accuracy for standard analyses. The obtained results show that the proposed model can be remarkably useful for the traction system design as well as for investigating the effects of short-circuit conditions on other circuits, such as telecom circuits, power-supply equipment, and signaling track circuits.
Autors: Battistelli, L.;Pagano, M.;Proto, D.;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Jul 2011, volume: 26, issue:3, pages: 1459 - 1466
Publisher: IEEE
 
» 3-D Active Meshes: Fast Discrete Deformable Models for Cell Tracking in 3-D Time-Lapse Microscopy
Abstract:
Variational deformable models have proven over the past decades a high efficiency for segmentation and tracking in 2-D sequences. Yet, their application to 3-D time-lapse images has been hampered by discretization issues, heavy computational loads and lack of proper user visualization and interaction, limiting their use for routine analysis of large data-sets. We propose here to address these limitations by reformulating the problem entirely in the discrete domain using 3-D active meshes, which express a surface as a discrete triangular mesh, and minimize the energy functional accordingly. By performing computations in the discrete domain, computational costs are drastically reduced, whilst the mesh formalism allows to benefit from real-time 3-D rendering and other GPU-based optimizations. Performance evaluations on both simulated and real biological data sets show that this novel framework outperforms current state-of-the-art methods, constituting a light and fast alternative to traditional variational models for segmentation and tracking applications.
Autors: Dufour, A.;Thibeaux, R.;Labruyere, E.;Guillen, N.;Olivo-Marin, J.-C.;
Appeared in: IEEE Transactions on Image Processing
Publication date: Jul 2011, volume: 20, issue:7, pages: 1925 - 1937
Publisher: IEEE
 
» 3D analytical modelling of subthreshold characteristics in vertical Multiple-gate FinFET transistors
Abstract:
In this work, a model is developed in order to obtain analytical expressions of the subthreshold characteristics of advanced Pi-gate FET transistors. Based on the solution of the 3D Laplace's equation, the interface coupling in the structure is accurately described and the potential calculated. Using the 'most leaky path' approach, the potential is then integrated and expressed as a simplified formula for the subthreshold current of Pi-gate FET transistors. The short-channel characteristics (subthreshold current, subthreshold slope, Roll-off and DIBL) are calculated and compared to experimental data with an excellent agreement, without the need of any fitting parameters. Additionally, it is...
Autors: Romain, Ritzenthaler , François, Lime , Olivier, Faynot , Sorin, Cristoloveanu , Benjamin, Iñiguez
Appeared in: Solid-State Electronics
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» 4G mobile licenses under auction in Spain [Global Communications News Letter]
Abstract:
The Ministry of Industry announced in February 2010 [1] a plan to collect between ϵ1500 and ϵ2000 million with the auction of new frequency bands for mobile telephony. The bid for a total of 310 MHz in different frequency bands will be done by a mixed formula: 90 percent through auctions and 10 percent by competition.
Autors: Lanas, F.F.;G??mez, P.P.;
Appeared in: IEEE Communications Magazine
Publication date: Jul 2011, volume: 49, issue:7, pages: 1 - 4
Publisher: IEEE
 
» 4H-SiC BJTs With Record Current Gains of 257 on (0001) and 335 on ( )
Abstract:
We demonstrate 4H-SiC bipolar junction transistors (BJTs) with record current gains. An improved current gain was achieved by utilizing optimized device geometry and continuous epitaxial growth of the emitter–base junction, combined with an intentional deep-level-reduction process based on thermal oxidation to improve the lifetime in p-SiC base. A current gain ( ) of 257 was achieved for 4H-SiC BJTs fabricated on the (0001) Si face. A gain of 257 is twice as large as the previous record gain. We also demonstrate BJTs on the ( ) C face that showed the highest of 335 among the SiC BJTs ever reported.
Autors: Miyake, H.;Kimoto, T.;Suda, J.;
Appeared in: IEEE Electron Device Letters
Publication date: Jul 2011, volume: 32, issue:7, pages: 841 - 843
Publisher: IEEE
 
» 50-Hz Frequency [History]
Abstract:
The so-called “European” frequency of 50 Hz is one of the two standard frequencies that govern the electric power supply worldwide. As with 60 Hz, the “American” standard frequency, the history of 50 Hz is also specific and characterized by its own course of development from its first use up to final standards, involving various steps in between.
Autors: Neidhöfer, Gerhard;
Appeared in: IEEE Power and Energy Magazine
Publication date: Jul 2011, volume: 9, issue:4, pages: 66 - 81
Publisher: IEEE
 
» 75-km SMF Transmission of Optical 16 QAM Signal Generated by a Monolithic Quad-Parallel Mach–Zehnder Optical Modulator
Abstract:
We demonstrate 75-km single-mode fiber transmission of a 40-Gb/s optical 16-level quadrature amplitude modulation (16QAM) signal generated by a quad-parallel Mach–Zehnder optical modulator (QPMZM), where four Mach–Zehnder structures are embedded in parallel monolithically on a lithium niobate substrate. Owing to the optical 16QAM signal generation method based on the coherent superposition in the QPMZM and improved coherent receiver utilizing digital filters, improvement of receiver sensitivity has been achieved as well. The experimentally obtained receiver sensitivity for near the forward-error correction limit and power penalty due to transmission are experimentally evaluated as 16.3 dB and about 2–3 dB, respectively.Pub _bookmark Command="[Quick Mark]"
Autors: Chiba, A.;Sakamoto, T.;Kawanishi, T.;Higuma, K.;Sudo, M.;Ichikawa, J.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jul 2011, volume: 23, issue:14, pages: 977 - 979
Publisher: IEEE
 
» -Based Ultraviolet Detectors Series
Abstract:
In this letter, -based ultraviolet (UV) detector series with Pt electrodes were fabricated. The thin films were prepared by a sol–gel method and characterized by means of X-ray diffraction and UV–visible absorption spectra. At 5 V bias, the dark currents of the detectors were less than 7 nA; under radiation of UV light, a high responsivity rate of 470 A/W was achieved at 270 nm for the detector. The results showed that, at low Zr doping, the photoresponse was greatly improved, whereas at high Zr doping, the response peaks shift to the short-wavelength direction, which provides a new platform to fabricate solar-blind UV detectors.
Autors: Zhang, H.;Feng, C.;Liu, C.;Xie, T.;Zhou, J.;Ruan, S.;
Appeared in: IEEE Electron Device Letters
Publication date: Jul 2011, volume: 32, issue:7, pages: 934 - 936
Publisher: IEEE
 
» Bridge Based on an Automated Synchronous Sampling System
Abstract:
An RLC bridge based on an automated synchronous sampling system has been developed using commercially available high-resolution analog-to-digital and digital-to-analog converters. This bridge allows the comparison of any kind of impedance standards in the four-terminal-pair configuration at frequencies between 50 Hz and 20 kHz within a range from 1 Ω to 100 kΩ. An automatic balance of the bridge is carried out using a downhill simplex algorithm. Consistency checks have been realized by comparing resistance, inductance, and capacitance standards at different frequencies. The consistency of the measured voltage ratio is better than 20 μV/V over the whole frequency range and even smaller than 5 μV/V around 1 kHz. Finally, the results of the calibration of a 10-nF capacitance standard have been compared to those obtained using a commercial high-accuracy capacitance bridge. The difference is smaller than the commercial bridge specifications over the whole frequency range.
Autors: Overney, F.;Jeanneret, B.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jul 2011, volume: 60, issue:7, pages: 2393 - 2398
Publisher: IEEE
 
» A 0.12 mm 7.4 W Micropower Temperature Sensor With an Inaccuracy of 0.2 C (3 ) From 30 C to 125 C
Abstract:
This paper describes the design of a CMOS smart temperature sensor intended for RFID applications. The PNP-based sensor uses a digitally-assisted readout scheme that reduces the complexity and area of the analog circuitry and simplifies trimming. A key feature of this scheme is an energy-efficient two-step zoom ADC that combines a coarse 5-bit SAR conversion with a fine 10-bit conversion. After a single trim at 30 , the sensor achieves an inaccuracy of from to 125 . It also achieves a resolution of 15 mK at a conversion rate of 10 Hz. The sensor occupies only 0.12 in a 0.16 CMOS process, and draws 4.6 from a 1.6 V to 2 V supply. This corresponds to a minimum power dissipation of 7.4 , the lowest ever reported for a precision temperature sensor.
Autors: Souri, K.;Makinwa, K. A. A.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2011, volume: 46, issue:7, pages: 1693 - 1700
Publisher: IEEE
 
» A 0.18?m CMOS transimpedance amplifier with 26dB dynamic range at 2.5Gb/s
Abstract:
 Research highlights: ? A 1.8-V 0.18-?m CMOS transimpedance amplifier targeting 2.5 Gb/s is presented. ? A good noise performance is achieved, leading to an optical sensitivity of -26 dBm. ? The proposed TIA incorporates a new technique to enhance the input dynamic range. ? It shows an optical power dynamic range above 26 dB without duty cycle distortion. ? Our proposal is also suitable for technologies with an even lower supply voltage.

Autors: A new transimpedance amplifier (TIA) for 2.5Gb/s optical communications fabricated in a standard 0.18?m CMOS process is presented. The proposed TIA is based on a conventional structure with an inverting voltage amplifier and a feedback resistor, but
Appeared in: Microelectronics Journal
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A 1.8 W 60 nV Hz Capacitively-Coupled Chopper Instrumentation Amplifier in 65 nm CMOS for Wireless Sensor Nodes
Abstract:
This paper presents a low-power precision instrumentation amplifier intended for use in wireless sensor nodes. It employs a capacitively-coupled chopper topology to achieve a rail-to-rail input common-mode range as well as high power efficiency. A positive feedback loop is employed to boost its input impedance, while a ripple reduction loop suppresses the chopping ripple. To facilitate bio-potential sensing, an optional DC servo loop may be employed to suppress electrode offset. The IA achieves 1 offset, 0.16% gain inaccuracy, 134 dB CMRR, 120 dB PSRR and a noise efficiency factor of 3.3. The instrumentation amplifier was implemented in a 65 nm CMOS technology. It occupies only 0.1 chip area (0.2 with the DC servo loop) and consumes 1.8 current (2.1 with the DC servo loop) from a 1 V supply.
Autors: Fan, Q.;Sebastiano, F.;Huijsing, J. H.;Makinwa, K. A. A.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2011, volume: 46, issue:7, pages: 1534 - 1543
Publisher: IEEE
 
» A 10 V Josephson Voltage Standard Comparison Between NIST and INMETRO as a Link to BIPM
Abstract:
This paper describes a 10 V Josephson Voltage Standard (JVS) direct comparison between the National Institute of Standards and Technology (NIST) and the Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (INMETRO) using automatic data acquisition. The results were in agreement to within 1.1 nV and the mean difference between the two JVSs at 10 V is 0.54 nV with a pooled combined standard uncertainty of 1.48 nV. Considering a recent JVS comparison between NIST and the Bureau International des Poids et Mesures (BIPM), the difference between INMETRO and the BIPM thus was found to be -0.26 nV with a standard uncertainty of 1.76 nV. INMETRO JVS improvements since the 2006 INMETRO-BIPM comparison are also described.
Autors: Landim, R.P.;Yi-hua Tang;Afonso, E.;Ferreira, V.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jul 2011, volume: 60, issue:7, pages: 2353 - 2358
Publisher: IEEE
 
» A 140 Mb/s to 1.96 Gb/s Referenceless Transceiver With 7.2 s Frequency Acquisition Time
Abstract:
This paper presents a design of a wide-range transceiver without an external reference clock. The self-biased and multi-band PLL with self-initialization technique is used for the wide-operating range of 140 Mb/s to 1.96 Gb/s and fast frequency acquisition time of 7.2 s. A linear phase detector which has no dead-zone problem is proposed for a phase adjustment with a low-jitter performance. The rms jitter of the recovered clock is 11.4 ps at 70 MHz operation. The overall transceiver consumes 388 mW at 2.5 V supply and occupies 3.41 mm in a 0.25- m 1P5M CMOS technology.
Autors: Jung, I.;Shin, D.;Kim, T.;Kim, C.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jul 2011, volume: 19, issue:7, pages: 1310 - 1315
Publisher: IEEE
 
» A 160 120-Pixels Range Camera With In-Pixel Correlated Double Sampling and Fixed-Pattern Noise Correction
Abstract:
This paper presents the design and electro-optical test of a 160 120-pixels CMOS sensor specifically conceived for Time-Of-Flight 3D imaging. The in-pixel processing allows the implementation of Indirect Time-Of-Flight technique for distance measurement with reset noise removal through Correlated Double Sampling and embedded fixed-pattern noise reduction, whereas a fast readout operation allows the pixels values to be streamed out at a maximum rate of 10 MSample/s. The imager can operate as a fast 2D camera up to 458 fps, as a 3D camera up to 80 fps, or even coupling both operation modes. The chip has been fabricated using a standard 0.18 1P4M 1.8 V CMOS technology with MIM capacitors. The resulting pixel has a pitch of 29.1 with a fill-factor of 34% and includes 66 transistors. Distance measurements up to 4.5 m have been performed with pulsed laser light, achieving a best precision of 10 cm at 1 m in real-time at 55 fps and 175 mA current consumption.
Autors: Perenzoni, M.;Massari, N.;Stoppa, D.;Pancheri, L.;Malfatti, M.;Gonzo, L.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2011, volume: 46, issue:7, pages: 1672 - 1681
Publisher: IEEE
 
» A 1V CMOS programmable accurate charge pump with wide output voltage range
Abstract:
 Highlights: ? We propose a 1V, programmable, accurate, high speed, single-ended charge pump. ? It exhibits a maximum DC current mismatch of 1% and charge mismatch of 6%. ? The output voltage range is 0.15-0.85V for the entire range of currents (20-200?A). ? Charge mismatch and current glitches are reduced using additional switches at the output.

Autors: A 1V, programmable, accurate, high speed, single-ended charge pump is proposed, suitable for low voltage PLLs. It is designed in TSMC 90-nm digital CMOS process and it consists of four switches in a current steering configuration, a unity gain rail t
Appeared in: Microelectronics Journal
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A 2-dimensional fully analytical model for design of high voltage junction barrier Schottky (JBS) diodes
Abstract:
 Highlights: ? We derive closed form I-V equations for high voltage JBS diodes. ? 2-dimensional analytical model is fitted with simulation and experimental data. ? We compare honeycomb layout of anode contact with rectangular stripes.

Autors: A physics-based closed form analytical model for the reverse leakage current of a high voltage junction barrier Schottky (JBS) diode is developed and shown to agree with experimental results. Maximum electric field "seen" by the Schottky contact is c
Appeared in: Solid-State Electronics
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A 2.2 mA 4.3 mm ASIC for a 1000 /s 2-Axis Capacitive Micro-Gyroscope
Abstract:
The interface for a capacitive 2-axis micro-gyroscope is implemented in a 0.35- m HVCMOS technology with a total area of 4.3 mm . The ASIC comprises the complete analog interface electronics for the gyroscope, while the focus of the design is in maintaining low supply current and in reducing the chip area. The paper reports the design of reference circuits, high-voltage generation, drive-loop and the capacitive open-loop readout circuits. The prototype sensor that is measured is assembled by directly wire-bonding the stacked dies comprising the interface electronics and the sensor element. The noise floors of the two sensors are 0.028 /s/ for z-axis and 0.032 /s/ for y-axis. The supply current of the chip is 2.2 mA from a 3 V-supply.
Autors: Aaltonen, L.;Kalanti, A.;Pulkkinen, M.;Paavola, M.;Kamarainen, M.;Halonen, K. A. I.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2011, volume: 46, issue:7, pages: 1682 - 1692
Publisher: IEEE
 
» A 2.4 GS/s, Single-Channel, 31.3 dB SNDR at Nyquist, Pipeline ADC in 65 nm CMOS
Abstract:
This paper presents a high-speed single-channel pipeline analog-to-digital converter sampling at 2.4 GS/s. The high sample rate is achieved through the use of fast open-loop current-mode amplifiers and the early comparison scheme. The bounds on the sub-ADC sampling instance are analyzed based on sufficient settling for a decision as well as metastability. Implemented in a 65 nm general purpose CMOS technology the SNDR is above 30.1 dB in the Nyquist band, being 34.1 and 31.3 dB at low frequency and Nyquist, respectively. This shows that multi-GS/s pipeline ADCs are feasible as key building blocks in interleaved structures.
Autors: Sundstrom, T.;Svensson, C.;Alvandpour, A.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2011, volume: 46, issue:7, pages: 1575 - 1584
Publisher: IEEE
 
» A 26 W 8 bit 10 MS/s Asynchronous SAR ADC for Low Energy Radios
Abstract:
This paper presents an asynchronous SAR ADC for flexible, low energy radios. To achieve excellent power efficiency for a relatively moderate resolution, various techniques are introduced to reduce the power consumption: custom-designed 0.5 fF unit capacitors minimize the analog power consumption while asynchronous dynamic logic minimizes the digital power consumption. The variability of the custom-designed capacitors is estimated by a specialized CAD tool and verified by chip measurements. An implemented 8-bit prototype in a 90 nm CMOS technology occupies 228 m 240 m including decoupling capacitors, and achieves an ENOB of 7.77 bit at a sampling frequency of 10.24 MS/s. The power consumption equals 26.3 W from a 1 V supply, thus resulting in an energy efficiency of 12 fJ/conversion-step. Moreover, the fully dynamic design, which is optimized for low-leakage, leads to a standby power consumption of 6 nW. In that way, the energy efficiency of this converter can be maintained down to very low sampling rates.
Autors: Harpe, P. J. A.;Zhou, C.;Bi, Y.;van der Meijs, N. P.;Wang, X.;Philips, K.;Dolmans, G.;de Groot, H.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2011, volume: 46, issue:7, pages: 1585 - 1595
Publisher: IEEE
 
» A 275-W Multitone Driven All-Fiber Amplifier Seeded by a Phase-Modulated Single-Frequency Laser for Coherent Beam Combining
Abstract:
We present what we believe to be a new approach of multitone driven amplifier for power scaling and coherent beam combining. A novel multitone seed is generated by a sine wave phase-modulated single-frequency laser and used for stimulated Brillouin scattering suppression of the amplifier. The theory for coherent beam combining of multitone lasers is presented for the first time. We optimize the all-fiber master-oscillator power-amplifier system with high scalability and flexibility based on compact, high efficiency Yb-doped fiber amplifier chain. With this amplifier system, we demonstrated a 275-W high-power output when driven by the phase-modulated single-frequency laser, while the ultimate output power is only 120 W when driven by the single-frequency laser. Scaling this amplifier to a higher power can be expected by adding pumps as the output power is limited by the pumps.Pub _bookmark Command="[Quick Mark]"
Autors: Wang, X.;Zhou, P.;Leng, J.;Du, W.;Ma, Y.;Xiao, H.;Zhu, J.;Dong, X.;Xu, X.;Liu, Z.;Zhao, Y.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jul 2011, volume: 23, issue:14, pages: 980 - 982
Publisher: IEEE
 
» A 2x2 MIMO Tri-Band Dual-Mode Direct-Conversion CMOS Transceiver for Worldwide WiMAX/WLAN Applications
Abstract:
This paper describes a fully integrated 130 nm CMOS 2x2 MIMO tri-band dual-mode transceiver for fixed and mobile WiMAX and IEEE 802.11a/b/g/n applications. The proposed transceiver features reduced RF interface (only 4 RF pins) with the wideband circuit topology of the LNA and drive amplifier that minimizes the performance degradation. With carefully chosen LO frequency planning, the transceiver is capable of operating at 2.3–2.7 GHz, 3.3–3.9 GHz, and as well as 5.1–5.9 GHz bands covering whole frequency spectrum of fixed and mobile WiMAX and WLAN. The measured noise figure of the receiver is 3.6–4.2, 4.2–4.7, and 5.4–6.2 dB for each 2/3/5 GHz bands respectively. The measured PLL phase noise from 1 kHz to 10 MHz is 0.5/0.8/0.95 rms degree for 2/3/5 GHz bands respectively. The transceiver ensures low EVM over the wide dynamic range due to linear RX and TX signal paths and low integrated PLL phase noise characteristics.
Autors: Lim, K.;Min, S.;Lee, S.;Park, J.;Kang, K.;Shin, H.;Shim, H.;Oh, S.;Kim, S.;Lee, J.;Yoo, C.;Chun, K.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2011, volume: 46, issue:7, pages: 1648 - 1658
Publisher: IEEE
 
» A 40 nm CMOS 0.4–6 GHz Receiver Resilient to Out-of-Band Blockers
Abstract:
A highly-linear software-defined radio operating from 400 MHz to 6 GHz is presented, with the purpose of removing any dedicated filtering at the antenna. Very high resilience to out-of-band interference is achieved thanks to a 2.5 V linear LNA and mixer-based RF blocker filter. The 2 mm , 40 nm digital CMOS receiver achieves 10 dBm out-of-band and 70 dBm calibrated at 3 dB NF. It tolerates 0 dBm blockers at 20 MHz offset with acceptable blocker NF.
Autors: Borremans, J.;Mandal, G.;Giannini, V.;Debaillie, B.;Ingels, M.;Sano, T.;Verbruggen, B.;Craninckx, J.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2011, volume: 46, issue:7, pages: 1659 - 1671
Publisher: IEEE
 
» A 400 W Hz-Range Lock-In A/D Frontend Channel for Infrared Spectroscopic Gas Recognition
Abstract:
This paper presents a low-power and fully integrated frontend channel for long-wave infrared spectroscopic gas recognition. The proposed channel circuitry includes: input sensor biasing, sub-Hz high-pass filtering and preamplification, differential blind cancellation, and lock-in A/D conversion. The proposed CMOS circuits make extensive use of transistor subthreshold operation and digital programmability. Experimental results are presented for a 0.3 mm 400 W channel prototype integrated in 0.35 m CMOS technology.
Autors: Sutula, S.;Ferrer, C.;Serra-Graells, F.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jul 2011, volume: 58, issue:7, pages: 1561 - 1568
Publisher: IEEE
 
» A 45nm CMOS miniature phase shifter with constant amplitude response
Abstract:
 Highlights: ? This work presents a comprehensive study of a RC bridge phase shifter. ? Analog phase shifter works at 24GHz and was fabricated in 45nm RF-CMOS process. ? Phase is controlled by varying DC voltage on a varactor.

Autors: We present analysis, optimization, design and characterization of an integrated passive analog phase shifter at 24GHz in a commercially available 45nm RF-CMOS process. The design is based on a well-known RC bridge topology, which was optimized for ma
Appeared in: Microelectronics Journal
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A 5 Mb/s UWB-IR Transceiver Front-End for Wireless Sensor Networks in 0.13 CMOS
Abstract:
This paper presents a fully integrated UWB-IR transceiver front-end operating in the 7.25–8.5 GHz band designed for high overall transmission and detection energy efficiency and robustness to interferers. The transceiver front-end features a pulsed transmitter that wakes up when triggered by a digital signal, generates a pulse, and automatically switches-off in less than 2 ns. The receiver includes an LNA, a VGA, a squarer, a windowed integrator, and a comparator to perform PPM demodulation of the data. A prototype of the transceiver front-end was integrated in a 0.13 CMOS technology. The transmitter delivers 13 pJ/pulse to the antenna consuming about 190 pJ/b, with an efficiency , well in excess of comparable designs. Using pulse polarity scrambling, it complies with the FCC spectral emission limits up to a pulse repetition frequency (PRF) of 5 MHz. The receiver achieves a sensitivity of 87 dBm at a PRF of 100 kHz, and of 70 dBm at a PRF of 5 MHz, while consuming 4.2 mW. It can tolerate interferers up to 12 dBm at 5.4 GHz.
Autors: Solda, S.;Caruso, M.;Bevilacqua, A.;Gerosa, A.;Vogrig, D.;Neviani, A.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2011, volume: 46, issue:7, pages: 1636 - 1647
Publisher: IEEE
 
» A 60-GHz Millimeter-Wave CMOS Integrated On-Chip Antenna and Bandpass Filter
Abstract:
This paper presents a first reported 60-GHz millimeter-wave integrated on-chip antenna and bandpass filter fabricated with a standard 0.18- complementary metal–oxide–semiconductor (CMOS) process. The on-chip coplanar waveguide (CPW) bandpass filter utilizes a backed-side half-wavelength resonator integrated with a CPW-fed Yagi antenna. A finite-element-method-based 3-D full-wave electromagnetic solver, i.e., the High-Frequency Structure Simulator, is used for design simulation. A detailed on-wafer measurement methodology for the on-chip antenna is presented. The Friis power transmission formula is used to determine the radiation power gain and antenna pattern. The possible effect of the probe radiation, which may affect the accuracy of the antenna measurement, is also investigated. The proposed integrated on-chip antenna–filter can be very useful for the integrated design of the 60-GHz CMOS single-chip radio-frequency transceiver.
Autors: Chuang, H.-R.;Yeh, L.-K.;Kuo, P.-C.;Tsai, K.-H.;Yue, H.-L.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jul 2011, volume: 58, issue:7, pages: 1837 - 1845
Publisher: IEEE
 
» A 65-nm CMOS Temperature-Compensated Mobility-Based Frequency Reference for Wireless Sensor Networks
Abstract:
A temperature-compensated CMOS frequency reference based on the electron mobility in a MOS transistor is presented. Over the temperature range from to 125 , the frequency spread of the complete reference is less than 0.5% after a two-point trim and less than 2.7% after a one-point trim. These results make it suitable for use in Wireless Sensor Network nodes. Fabricated in a baseline 65-nm CMOS process, the 150 kHz frequency reference occupies 0.2 and draws 42.6 from a 1.2-V supply at room temperature.
Autors: Sebastiano, F.;Breems, L. J.;Makinwa, K. A. A.;Drago, S.;Leenaerts, D. M. W.;Nauta, B.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2011, volume: 46, issue:7, pages: 1544 - 1552
Publisher: IEEE
 
» A 7 mW 20 MHz BW Time-Encoding Oversampling Converter Implemented in a 0.08 mm 65 nm CMOS Circuit
Abstract:
This work presents an area- and power-efficient realization of a new time-encoding oversampling converter (TEOC) consisting of a third-order continuous time (CT) loop filter and a self-oscillating pulse-width modulator (PWM). The modulator displays similar performance to that of a standard multibit CT- modulator but has the complexity of a single bit design. The time-encoding quantizer (TEQ) is implemented inside a modulator by replacing a multibit quantizer. An innovative TEQ is used to overcome design issues in a 1.0 V supply-voltage 65 nm digital CMOS technology. The TEQ allows an exchange of amplitude-resolution by time-resolution. The approach of time-resolution alleviates the scaling difficulties of mixed-signal circuits in nano-scale technologies. The TEOC features a 63 dB dynamic-range and a peak-SNDR of 61 dB over a 20 MHz signal bandwidth. Clocked at 2.5 GHz, the complete ADC consumes 7 mW from a single 1.0 V supply, including also the reference buffers. The ADC core results in an attractively small area of 0.08 mm and in a figure-of-merit of 0.17 pJ/conversion-step.
Autors: Prefasi, E.;Paton, S.;Hernandez, L.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2011, volume: 46, issue:7, pages: 1562 - 1574
Publisher: IEEE
 
» A Backscattering Model Incorporating the Effective Carrier Temperature in Nano-MOSFET
Abstract:
In this letter, we propose a channel backscattering model in which increased carrier temperature at the top of the potential energy barrier in the channel is taken into account. This model represents an extension of a previous model by the same authors, which highlighted the importance of considering the partially ballistic transport between the source contact and the top of the potential energy barrier in the channel. The increase in carrier temperature is precisely due to energy dissipation between the source contact and the top of the barrier caused by high saturation current. To support our discussion, accurate 2-D full-band Monte Carlo device simulations with quantum correction have been performed in double-gate n-type metal–oxide–semiconductor field-effect transistors for different geometry (gate length down to 10 nm), biases, and lattice temperatures. Including the effective carrier temperature is particularly important to properly treat the high-inversion regime, where previous backscattering models usually fail.
Autors: Giusi, G.;Iannaccone, G.;Crupi, F.;Ravaioli, U.;
Appeared in: IEEE Electron Device Letters
Publication date: Jul 2011, volume: 32, issue:7, pages: 853 - 855
Publisher: IEEE
 
» A Bayesian Approach to Passive Sonar Detection and Tracking in the Presence of Interferers
Abstract:
In this paper, a Bayesian approach to tracking a single target of interest (TOI) using passive sonar is presented. The TOI is assumed to be in the presence of other loud interfering targets, or interferers. To account for the interferers, a single-signal likelihood function (SSLF) is proposed which uses maximum-likelihood estimates (MLEs) in place of nuisance parameters. Since there is uncertainty in signal origin, we propose a computationally efficient method for computing association probabilities. The final proposed SSLF accounts for sidelobe interference from other signals, reflects the uncertainty caused by the array beampattern, is signal-to-noise ratio (SNR) dependent, and reflects uncertainty caused by unknown signal origin. Various examples are considered, which include moving and stationary targets. For the examples, the sensors are assumed to be uniformly spaced linear arrays. The arrays may be stationary or moving and there may be one or more present.
Autors: Yocom, B. A.;La Cour, B. R.;Yudichak, T. W.;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jul 2011, volume: 36, issue:3, pages: 386 - 405
Publisher: IEEE
 
» A Bayesian Hierarchical Correlation Model for fMRI Cluster Analysis
Abstract:
Data-driven cluster analysis is potentially suitable to search for, and discriminate between, distinct response signals in blood oxygenation level-dependent functional magnetic resonance imaging (BOLD fMRI), which appear during cerebrovascular disease. In contrast to model-driven methods, which test for a particular BOLD signal whose shape must be given beforehand, data-driven methods generate a set of BOLD signals directly from the fMRI data by clustering voxels into groups with correlated time signals. Here, we address the problem of selecting only the clusters that represent genuine responses to the experimental stimulus by modeling the correlation structure of the clustered data using a Bayesian hierarchical model. The model is empirically justified by demonstrating the hierarchical organization of the voxel correlations after cluster analysis. BOLD signal discrimination is demonstrated using: 1) simulations that contain multiple pathological BOLD response signals; and 2) fMRI data acquired during an event-related motor task. These demonstrations are compared with results from a model-driven method based on the general linear model. Our simulations show that the data-driven method can discriminate between the BOLD response signals, while the model-driven method only finds one signal. For fMRI, the data-driven method distinguishes between the BOLD signals appearing in the sensorimotor cortex and those in basal ganglia and putamen, while the model-driven method combines these signals into one activation map. We conclude that the proposed data-driven method provides an objective framework to identify and discriminate between distinct BOLD response signals.
Autors: Gomez-Laberge, C.;Adler, A.;Cameron, I.;Nguyen, T.;Hogan, M. J.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jul 2011, volume: 58, issue:7, pages: 1967 - 1976
Publisher: IEEE
 
» A Bio-Inspired Cochlear Heterodyning Architecture for an RF Fovea
Abstract:
We discuss the use of cochlear models for spectrum analysis at radio frequencies. We describe performance characteristics of such models, including noise, dynamic range, and frequency resolution. We show that the addition of phase information improves frequency estimation as compared to the use of amplitude information alone. In particular, the use of both amplitude and phase information in a novel nonlinear bio-inspired center-surround coincidence-detection stage simultaneously improves frequency estimation and implements a lowpass-to-bandpass transformation on cochlear outputs. In order to further improve frequency estimation we propose a novel wireless receiver architecture that is a broadband generalization of narrowband heterodyning systems commonly used in radio. We term this architecture cochlear heterodyning. It exploits the efficiency of cochlear spectrum analysis to perform parallel, multi-scale analysis of wideband signals and can be constructed with cochlea-like traveling-wave structures. When combined with our prior work on an RF cochlea, such architectures may be useful in cognitive radios for creating RF foveas that select narrowband components present within wideband, but spectrally sparse signals. The operation of RF foveas is analogous to how the eye foveates on narrow but interesting portions of an image. Analogies between spectrum analysis and the process of successive-subranging analog-to-digital conversion illustrate how successively finer frequency resolution is achieved in an RF fovea. Finally, we show that RF foveas can be used in feedback loops to perform interference cancellation.
Autors: Mandal, S.;Sarpeshkar, R.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jul 2011, volume: 58, issue:7, pages: 1647 - 1660
Publisher: IEEE
 
» A Biologically Inspired Measure for Coexpression Analysis
Abstract:
Two genes are said to be coexpressed if their expression levels have a similar spatial or temporal pattern. Ever since the profiling of gene microarrays has been in progress, computational modeling of coexpression has acquired a major focus. As a result, several similarity/distance measures have evolved over time to quantify coexpression similarity/dissimilarity between gene pairs. Of these, correlation coefficient has been established to be a suitable quantifier of pairwise coexpression. In general, correlation coefficient is good for symbolizing linear dependence, but not for nonlinear dependence. In spite of this drawback, it outperforms many other existing measures in modeling the dependency in biological data. In this paper, for the first time, we point out a significant weakness of the existing similarity/distance measures, including the standard correlation coefficient, in modeling pairwise coexpression of genes. A novel measure, called BioSim, which assumes values between -1 and +1 corresponding to negative and positive dependency and 0 for independency, is introduced. The computation of BioSim is based on the aggregation of stepwise relative angular deviation of the expression vectors considered. The proposed measure is analytically suitable for modeling coexpression as it accounts for the features of expression similarity, expression deviation and also the relative dependence. It is demonstrated how the proposed measure is better able to capture the degree of coexpression between a pair of genes as compared to several other existing ones. The efficacy of the measure is statistically analyzed by integrating it with several module-finding algorithms based on coexpression values and then applying it on synthetic and biological data. The annotation results of the coexpressed genes as obtained from gene ontology establish the significance of the introduced measure. By further extending the BioSim measure, it has been shown that one can effectively identify the - - variability in the expression patterns over multiple phenotypes. We have also extended BioSim to figure out pairwise differential expression pattern and coexpression dynamics. The significance of these studies is shown based on the analysis over several real-life data sets. The computation of the measure by focusing on stepwise time points also makes it effective to identify partially coexpressed genes. On the whole, we put forward a complete framework for coexpression analysis based on the BioSim measure.
Autors: Bandyopadhyay, S.;Bhattacharyya, M.;
Appeared in: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Publication date: Jul 2011, volume: 8, issue:4, pages: 929 - 942
Publisher: IEEE
 
» A Biologically Inspired Object Spectral-Texture Descriptor and Its Application to Vegetation Classification in Power-Line Corridors
Abstract:
The use of appropriate features to represent an output class or object is critical for all classification problems. In this letter, we propose a biologically inspired object descriptor to represent the spectral-texture patterns of images or objects. The proposed feature descriptor is generated from the pulse spectral frequencies (PSFs) of a pulse-coupled neural network, which is invariant to rotation, translation, and small scale changes. The proposed method is first evaluated in a rotation- and scale-invariant texture classification using the University of Southern California Signal and Image Processing Institute texture database. It is further evaluated in an application of vegetation species classification in power-line corridor monitoring using airborne multispectral aerial imagery. The results from the two experiments demonstrate that the PSF feature is effective in representing the spectral-texture patterns of objects, and it shows better results than classic color histogram and texture features.
Autors: Li, Z.;Hayward, R.;Walker, R.;Liu, Y.;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jul 2011, volume: 8, issue:4, pages: 631 - 635
Publisher: IEEE
 
» A Burst-Mode APD-ROSA Using Reset Signal With Less Than 100 ns Response for 1G/10G-EPON Dual-Rate Optical Transceivers
Abstract:
A burst-mode APD-ROSA using a reset signal with a very short response time to a burst-mode optical input signal ( nm, modulation formats of on-off-keying) for a 10G-EPON and GE-PON dual-rate system was developed. We analytically investigated the relationship between the response time and the multiplication characteristics of an APD to reduce the response time. From the calculation results, we determined a suitable resistance for a bias circuit that enabled us to obtain three key characteristics of burst-mode receiver performance, namely high sensitivity, wide dynamic range and short response time. We fabricated an APD-ROSA based on the calculation results, and demonstrated burst-mode receiver operation with a fast response of about 80 ns but without degrading the sensitivity or distorting the waveform.
Autors: Ito, T.;Kurosaki, T.;Nakamura, M.;Nishihara, S.;Ohtomo, Y.;Okada, A.;Yoneyama, M.;
Appeared in: Journal of Lightwave Technology
Publication date: Jul 2011, volume: 29, issue:14, pages: 2089 - 2101
Publisher: IEEE
 
» A CANDECOMP/PARAFAC Perspective on Uniqueness of DOA Estimation Using a Vector Sensor Array
Abstract:
We address the uniqueness problem in estimating the directions-of-arrival (DOAs) of multiple narrowband and fully polarized signals impinging on a passive sensor array composed of identical vector sensors. The data recorded on such an array present the so-called “multiple invariances,” which can be linked to the CANDECOMP/PARAFAC (CP) model. CP refers to a family of low-rank decompositions of three-way or higher way (mutidimensional) data arrays, where each dimension is termed as a “mode.” A sufficient condition is derived for uniqueness of the CP decomposition of a three-way (three mode) array in the particular case where one of the three loading matrices, each associated to one mode, involved in the decomposition has full column rank. Based on this, upper bounds on the maximal number of identifiable DOAs are deduced for the two typical cases, i.e., the general case of uncorrelated or partially correlated sources and the case where the sources are coherent.
Autors: Guo, X.;Miron, S.;Brie, D.;Zhu, S.;Liao, X.;
Appeared in: IEEE Transactions on Signal Processing
Publication date: Jul 2011, volume: 59, issue:7, pages: 3475 - 3481
Publisher: IEEE
 
» A Characterization of the Performance of a MEMS Gyroscope in Acoustically Harsh Environments
Abstract:
Microelectromechanical systems (MEMS) gyroscopes are typically smaller and less expensive than their macroscale counterparts. For this reason, they are being used in many new applications, including in harsh environments. It has been well documented that the performance of unprotected MEMS gyroscopes can be deleteriously affected by exposure to mechanical shock or high-frequency vibrations. The results of this investigation experimentally demonstrate that MEMS gyroscopes are also susceptible to high-power high-frequency acoustic noise when acoustic energy frequency components are close to the resonating frequency of the gyroscope's proof mass. Additionally, due to microfabrication tolerances and the resulting differences between otherwise identical devices, there can be significant differences in the acoustically sensitive bandwidth between otherwise identical MEMS gyroscopes. This phenomenon is characterized for the ADXRS300 MEMS gyroscope.
Autors: Dean, R.N.;Castro, S.T.;Flowers, G.T.;Roth, G.;Ahmed, A.;Hodel, A.S.;Grantham, B.E.;Bittle, D.A.;Brunsch, J.P.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jul 2011, volume: 58, issue:7, pages: 2591 - 2596
Publisher: IEEE
 
» A CMOS Single-Chip Gas Recognition Circuit for Metal Oxide Gas Sensor Arrays
Abstract:
This paper presents a CMOS single-chip gas recognition circuit, which encodes sensor array outputs into a unique sequence of spikes with the firing delay mapping the strength of the stimulation across the array. The proposed gas recognition circuit examines the generated spike pattern of relative excitations across the population of sensors and looks for a match within a library of 2-D spatio-temporal spike signatures. Each signature is drift insensitive, concentration invariant and is also a unique characteristic of the target gas. This VLSI friendly approach relies on a simple spatio-temporal code matching instead of existing computationally expensive pattern matching statistical techniques. In addition, it relies on a novel sensor calibration technique that does not require control or prior knowledge of the gas concentration. The proposed gas recognition circuit was implemented in a 0.35 CMOS process and characterized using an in-house fabricated 4 4 tin oxide gas sensor array. Experimental results show a correct detection rate of 94.9% when the gas sensor array is exposed to propane, ethanol and carbon monoxide.
Autors: Ng, K. T.;Boussaid, F.;Bermak, A.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jul 2011, volume: 58, issue:7, pages: 1569 - 1580
Publisher: IEEE
 
» A Compensation Method to Measure the Mutual Inductance at Low Frequency
Abstract:
Traditionally, the most precise way to get the mutual inductance value is by a Campbell calculable mutual inductor. Here, an approach of measuring the mutual inductance at low frequency with compensation method is described. A multi-channel direct digital frequency synthesis source is developed to provide stable and precise phase. The mutual inductance is traced to the value of the frequency and resistance directly. The measurement uncertainty is 0.43 ppm at present and could be improved further.
Autors: Zhengkun Li;Zhonghua Zhang;Qing He;Yaqiong Fu;Jianting Zhao;Bing Han;Shisong Li;Jiang Lan;Chen Li;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jul 2011, volume: 60, issue:7, pages: 2292 - 2297
Publisher: IEEE
 
» A comprehensive study of various etch processes for the removal of silicide-block-film in submicron CMOS technologies
Abstract:
image

Autors: The removal of silicide-block-film is crucial for device stability, reliability and subsequent silicide formation. In this paper, various silicide block etch processes, i.e. dry and wet etch, were studied and compared. Possible plasma charging damage
Appeared in: Microelectronic Engineering
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A confirmation-based geocast routing algorithm for street lighting systems
Abstract:
image

Autors:

Graphical abstract

 Graphical abstract:  Highlights: ? Instable wireless communication nature. ? Appropriated routing protocol for urban networks. ? Acknowledgment mechanism based on selecting other neighbors' nodes. ? Proposed protocol produ
Appeared in: Computers & Electrical Engineering
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A Consensus Tree Approach for Reconstructing Human Evolutionary History and Detecting Population Substructure
Abstract:
The random accumulation of variations in the human genome over time implicitly encodes a history of how human populations have arisen, dispersed, and intermixed since we emerged as a species. Reconstructing that history is a challenging computational and statistical problem but has important applications both to basic research and to the discovery of genotype-phenotype correlations. We present a novel approach to inferring human evolutionary history from genetic variation data. We use the idea of consensus trees, a technique generally used to reconcile species trees from divergent gene trees, adapting it to the problem of finding robust relationships within a set of intraspecies phylogenies derived from local regions of the genome. Validation on both simulated and real data shows the method to be effective in recapitulating known true structure of the data closely matching our best current understanding of human evolutionary history. Additional comparison with results of leading methods for the problem of population substructure assignment verifies that our method provides comparable accuracy in identifying meaningful population subgroups in addition to inferring relationships among them. The consensus tree approach thus provides a promising new model for the robust inference of substructure and ancestry from large-scale genetic variation data.
Autors: Ming-Chi Tsai;Blelloch, G.E.;Ravi, R.;Schwartz, R.;
Appeared in: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Publication date: Jul 2011, volume: 8, issue:4, pages: 918 - 928
Publisher: IEEE
 
» A Correlation-Based Islanding-Detection Method Using Current-Magnitude Disturbance for PV System
Abstract:
Since islanding of photovoltaic (PV) generation can cause safety problems, it should be prevented. This paper proposes a correlation-based islanding-detection method (IDM) using current-magnitude disturbance for a PV system. As an islanding-detection index, this paper uses the correlation factor between current-magnitude disturbance and the corresponding inverter output voltage. The proposed IDM uses the characteristics in which the up/down current disturbance has a strong correlation with the PV output voltage when islanding occurs. The proposed method has fast islanding capability and high power quality. For verification of the proposed method, the simulated and experimental results of a 3-kW PV inverter by IEEE Std. 929-2000 and IEEE Std. 1547.1-2005 are provided. The proposed correlation technique can be used in other active antiislanding methods based on the correlation between the current and voltage after islanding occurs.
Autors: Byung-Gyu Yu;Matsui, M.;Gwon-Jong Yu;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jul 2011, volume: 58, issue:7, pages: 2935 - 2943
Publisher: IEEE
 
» A Current-Comparator-Based System For Calibrating High-Voltage Current Transformers Under Actual Operating Conditions
Abstract:
The development of a computer-controlled current-comparator-based calibration system to determine the current ratio errors of high-voltage conventional and nonconventional current transformers (CTs) under actual operating conditions of high-voltage and distorted current waveforms up to 100 kV and 2000 A is described. The ratio errors of a CT are affected by the applied high voltage due to capacitive currents flowing in its winding. The errors are also affected by the phase angle of the primary currents with respect to the operating high voltage. Therefore, the new calibration system allows the phase angle of the test primary currents to be adjusted at power factors of zero lag through unity to zero lead. The uncertainty k = 2 of the new calibration system is estimated to be not more than 20 × 10-6 for both the in-phase and quadrature components of the measured ratio errors.
Autors: So, E.;Arseneau, R.;Bennett, D.;Frigault, M.E.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jul 2011, volume: 60, issue:7, pages: 2449 - 2454
Publisher: IEEE
 
» A Curved Multimorph Based Electrothermal Micromirror with Large Scan Range and Low Drive Voltage
Abstract:
We report a circular micromirror with a 1mm aperture that has an optical scan range of 60( at 0.68 V applied voltage and 11 mW power input. The mirror is actuated by a semicircular Aluminum (Al) - Tungsten (W) electrothermal multimorph that bends and twists upon controlled Joule heating. W acts as an active layer of the multimorph and a resistive heater. The curved actuator design not only maximizes the efficiency of chip area usage, but also achieves high resonant frequency due to torsional stiffness encountered during beam deformation. The first three resonant modes of the micromirror are at 104Hz,...
Autors: Sagnik, Pal , Huikai, Xie
Appeared in: Sensors and Actuators A: Physical
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A Cyclic Vernier TDC for ADPLLs Synthesized From a Standard Cell Library
Abstract:
This paper presents a cyclic Vernier time-to-digital converter (TDC) with digitally controlled oscillators (DCOs), targeted for a synthesizable all-digital phase locked loop (ADPLL). All functional blocks in the TDC are implemented with digital standard cells and placed-and-routed (P&R) by automatic design tools; thus, the TDC is portable and scalable to other process technologies. The effect of P&R mismatch is characterized in calibration mode, and utilized to achieve a minimum TDC resolution of 5.5 ps. The TDC was fabricated in a 65 nm CMOS process, and occupies 0.006 .
Autors: Park, Y.;Wentzloff, D. D.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jul 2011, volume: 58, issue:7, pages: 1511 - 1517
Publisher: IEEE
 
» A design methodology for fully-integrated MEMS and NEMS Pierce oscillators
Abstract:
This work proposes a generic methodology to evaluate the feasibility of designing a Pierce oscillator based on a micro or nanoresonator fabricated with any given CMOS technology and with the constraint of using only one single active transistor. Both the design and the transimpedance gain of the electronics are analytically determined for resonators with capacitive or resistive detection. This approach is applied and validated in the case of (a) an electrostatically-actuated clamped-clamped beam resonator using a capacitive transduction, and (b) a piezoresistive crossbeam, both based on a standard 0.13?m CMOS technology
Autors: G., Arndt , E., Colinet , J., Arcamone , J., Juillard
Appeared in: Sensors and Actuators A: Physical
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A Detailed Study of the Forming Stage of an Electrochemical Resistive Switching Memory by KMC Simulation
Abstract:
The forming stage characteristics of electrochemical-metallization resistive-switching-random-access-memory cells are studied with an improved kinetic Monte Carlo simulator. The filament topographies obtained at different forming voltage levels and the relationship between forming time and filament topographies are investigated in detail. The so-called “voltage–time dilemma” is simulated and studied. In addition, the various chemical and physical processes that produce these results are discussed. Finally, the simulated pattern is compared with experiments conducted on and systems.
Autors: Pan, F.;Yin, S.;Subramanian, V.;
Appeared in: IEEE Electron Device Letters
Publication date: Jul 2011, volume: 32, issue:7, pages: 949 - 951
Publisher: IEEE
 
» A Digital Standard Time Dissemination Architecture for Trustworthy Time Stamping
Abstract:
In this paper, a reliable and accurate two-layer standard time dissemination architecture is proposed to implement direct digital time traceability. First, the system uses a clock calibration procedure based on two-way time transfer over a general dialup telephone modem and achieves a couple of milliseconds of accuracy. Second, a delegation time stamping mechanism is implemented with a forward-secure proxy signature scheme to provide digital time stamps with enhanced validity assurance and with digital time traceability to the national standard. The Request for Comments 3161 time stamp token is then extended to embed the standard time reading and necessary verification certificates. These features allow users to remove the blind trust on a commercial time stamping authority's clock handling procedure.
Autors: Pei-Yih Ting;Fang-Dar Chu;Chia-Shu Liao;Huang-Tien Lin;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jul 2011, volume: 60, issue:7, pages: 2584 - 2589
Publisher: IEEE
 
» A Double-Heterojunction Bipolar Transistor Having a Degenerately Doped Emitter and Backward-Diode Base Contact
Abstract:
A double-heterojunction bipolar transistor having a degenerately doped emitter layer is investigated. The base–emitter Esaki diode introduces very low input impedance in the off- state but does not degrade the current gain at high forward bias. The heavily doped emitter layer makes it possible to scale the emitter-layer thickness considerably. The heavily doped emitter layer also allows contacting the base via the base–emitter backward diode. The high-frequency performance of the device is presented.
Autors: Cohen-Elias, D.;Kraus, S.;Cohen, S.;Gavrilov, A.;Ritter, D.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jul 2011, volume: 58, issue:7, pages: 1952 - 1956
Publisher: IEEE
 
» A face robot for autonomous simplified musical notation reading and singing
Abstract:
 Highlights: ? A face robot capable of performing unique musical entertainment function. ? A robot can read the simplified musical notation and sing the song in real time. ? Computer vision used to read the notation and voice synthesis to sing the content. ? Most people enjoy the autonomous musical notation reading and singing performance.

Autors: This research is aimed to devise an anthropomorphic robotic head with a human-like face and a sheet of artificial skin that can read a randomly composed simplified musical notation and sing the corresponding content of the song once. The face robot i
Appeared in: Robotics and Autonomous Systems
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A Fast Algorithm for Nonunitary Joint Diagonalization and Its Application to Blind Source Separation
Abstract:
A fast algorithm, named Complex-Valued Fast Frobenius DIAGonalization (CVFFDIAG), is proposed for seeking the nonunitary approximate joint diagonalizer of a given set of complex-valued target matrices. It adopts a multiplicative update to minimize the Frobenius-norm formulation of the approximate joint diagonalization problem. At each of multiplicative iterations, a strictly diagonally dominant updated matrix is obtained. This scheme ensures the invertibility of the diagonalizer. The CVFFDIAG relaxes several constraints on the target matrices and thus has much general applications. Furthermore, the special approximation of the cost function, the ingenious utilization of some structures and the adequate notation of concerned variables lead to the high computational efficiency of the proposed algorithm. Numerical simulations are conducted to illustrate good performances of the CVFFDIAG.
Autors: Xu, X.-F.;Feng, D.-Z.;Zheng, W. X.;
Appeared in: IEEE Transactions on Signal Processing
Publication date: Jul 2011, volume: 59, issue:7, pages: 3457 - 3463
Publisher: IEEE
 
» A Fast Discrete Wavelet Transform Algorithm for Visual Processing Applications
Abstract:
 Highlights: ? This work presents a fast algorithm, SMDWT. ? To solve the high complexity issue of the traditional 2-D DWT. ? he SMDWT itself is independent subband processing, which can significantly reduce complexity.

Autors: -- For visual processing applications, the two-demensional (2-D) Discrete Wavelet Transform (DWT) can be used to decompose an image into four-subband images. However, when a single band is required for a specific application, the four-band decomposit
Appeared in: Signal Processing
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A Fast MPSoC Virtual Prototyping for Intensive Signal Processing Applications
Abstract:
 Highlights: ? We define an appropriate MPSoC execution model for intensive signal processing applications. ? We implement the MPSoC execution model using a new Virtual Processor (VP)-based simulation technique. ? VP-based simulation is implemented in SystemC at a timed transactional level allowing a good trade-off between high simulation speed and performance estimation accuracy. ? Fast MPSoC virtual prototyping, data transfers and timing analysis, and reliable DSE for architectural optimizations are the main results of our approach.

Autors: Due to the growing computation rates of intensive signal processing applications, using Multiprocessor System on Chip (MPSoC) becomes an incontrovertible solution to meet the functional requirements. Today, Electronic System Level (ESL) design is con
Appeared in: Microprocessors and Microsystems
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A fast segmentation method for high-resolution color images of foreign fibers in cotton
Abstract:
 Highlights: ? The morphology's method was improved by defining the edge detection operator. ? The selection of experience value by iterative thresholding method was fit for most color images of cotton foreign fibers. ? A high-resolution color image segmentation of cotton foreign fibers was completed by the proposed method.

Autors: Foreign fibers in cotton seriously affect the quality of cotton products. The identification of foreign fibers in cotton is a critical step in the automated inspection of foreign fibers in cotton; image segmentation is crucial in this identification
Appeared in: Computers and Electronics in Agriculture
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A First-Order Characterization of Errors From Neglecting Stratigraphy in Forward and Inverse Passive Microwave Modeling of Snow
Abstract:
Large-scale snow hydrology has been studied via spaceborne passive microwave (PM) measurements for decades. Forward and inverse radiative transfer (RT) models of snow are utilized in this context but typically neglect snow stratigraphy. Our objective in this paper is to characterize the expected model error in PM brightness temperature predictions due to neglecting stratigraphy over a range of snow cover conditions. For 191 snowpits ranging from prairie to alpine, we performed side-by-side RT model runs including and ignoring stratigraphy via mass-weighted averages across stratigraphic layers; error was estimated by comparing the two RT model runs. Neglecting stratigraphy at 37 GHz led to approximately 10-K root mean square error (RMSE) for moderately deep (alpine) snow cover and to approximately 5-K RMSE for shallower (prairie) snow. RMSE across all types of snow was 1.67 and 26.9 K at 18.7 and 89 GHz, respectively. At 37 GHz, there was a low bias for deep snowpacks and a high bias for moderate-to-shallow snowpacks. Bias magnitude bias was dependent on vertical grain size variability. Based on these results and estimates of sensitivity of to snow depth, we estimated that snow depth RMSE due to neglecting stratigraphy approaches 50%.
Autors: Durand, M.;Kim, E. J.;Margulis, S. A.;Molotch, N. P.;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jul 2011, volume: 8, issue:4, pages: 730 - 734
Publisher: IEEE
 
» A Flexible KFCI Compensation for Head/Media Optimization in Perpendicular Disk Drives
Abstract:
Head/media matching is one of the key procedures used to ensure an acceptable performance, reliability and areal density of the perpendicular drives with multiple head/media pairs. To achieve the optimal bit error rate (BER) performance, head/media optimization is required to handle the BER variation of each pair within a single drive. Due to a large variation of the head/media performance, the mismatched KFCI slopes often lead the under- and over-compensation issues. In this paper, we derive the mathematical conditions of these problems as a function of the step adjustment size, the initial BER, the target BER and the KFCI slopes. The minimum number of adjustments for the weak and the maximum ones for the strong heads are determined. In addition, we perform an experiment on the perpendicular drives to study the BER variation of head/media. A new graphical explanation is proposed to clearly show how the under- and over-compensation issues occur. Finally, we propose a flexible KFCI compensation method based on the actual KFCI slopes. The experimental results on the failed drives from the current fixed-slope method show that the improvement in the BER performances is achieved using the proposed method.
Autors: Supnithi, P.;Bunsri, K.;Novid, M.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2011, volume: 47, issue:7, pages: 1805 - 1808
Publisher: IEEE
 
» A Flight to Quality
Abstract:
Early Airplanes had very few loads that required electrical power. Batteries supplied a few amps for radio communications and a couple of cockpit lights. Later, alternators were employed on piston engine airplanes to generate more electrical power. As aircraft evolved, increasing amounts of electrical power were required, and power quality standards were introduced to govern the distributed airplane voltage and frequency. Those standards specified either a 28-V dc system or a three-phase system with a regulated voltage at a constant frequency.
Autors: Said, W.;
Appeared in: IEEE Power and Energy Magazine
Publication date: Jul 2011, volume: 9, issue:4, pages: 38 - 45
Publisher: IEEE
 
» A Flip-Chip-Packaged 25.3 dBm Class-D Outphasing Power Amplifier in 32 nm CMOS for WLAN Application
Abstract:
A 2.4 GHz outphasing power amplifier (PA) is implemented in a 32 nm CMOS process. An inverter-based class-D PA topology is utilized to obtain low output impedance and good linearity in the outphasing system. MOS switch non-idealities, such as finite on-resistance and finite rise and fall times are analyzed for their impact on outphasing linearity and efficiency. Outphasing combining is performed via a transformer configured to achieve reduced loss at power backoff. The fabricated class-D outphasing PA delivers 25.3 dBm peak CW power with 35% total system Power Added Efficiency (includes all drivers). Average OFDM power is 19.6 dBm with efficiency 21.8% when transmitting WiFi signals with no linearization required. The PA is packaged in a flip-chip BGA package. Good linearity performance (ACPR and EVM) demonstrates the applicability of inverter-based class-D amplifiers for outphasing configurations.
Autors: Xu, H.;Palaskas, Y.;Ravi, A.;Sajadieh, M.;El-Tanani, M. A.;Soumyanath, K.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2011, volume: 46, issue:7, pages: 1596 - 1605
Publisher: IEEE
 
» A Frequency Domain State-Space Approach to LS Estimation and Its Application in Turbo Equalization
Abstract:
A frequency domain state-space approach to the least squares (LS) estimation for finite impulse response (FIR) system identification is proposed by exploiting the Toeplitz structure of the data matrix, leading to two low-complexity FFT (fast Fourier transform)-based unbiased recursive estimators. The proposed recursive estimators are applied to the smoothing estimation of time-varying frequency selective channels in turbo equalization systems, and channel estimation approaches with complexity per symbol are developed, where is the number of channel taps.
Autors: Guo, Q.;Huang, D.;
Appeared in: IEEE Transactions on Signal Processing
Publication date: Jul 2011, volume: 59, issue:7, pages: 3288 - 3300
Publisher: IEEE
 
» A Fully Integrated and Reconfigurable Architecture for Coherent Self-Testing of High Speed Analog-to-Digital Converters
Abstract:
This paper presents a reconfigurable architecture for coherent built-in self-testing (BIST) of high speed analog-to-digital converters (ADCs) with moderate resolutions. The proposed system is suited to be fully integrated with the ADC and, besides a low jitter clock reference, no other external high quality generators are required. The complete system comprises two synchronized phase-locked loops (PLLs), one based on a two-integrator oscillator capable of providing low distortion outputs and another based on a relaxation oscillator providing low jitter squared output, to allow coherent sampling. A detailed description of the building blocks of both PLLs is given as well as the techniques used to minimize area of the loop filters (LFs), to stabilize the output amplitude of the two-integrator oscillator to a known value, and to improve the total harmonic distortion (THD) of this oscillator. Post-layout simulations, in a 0.13 CMOS technology, of the proposed BIST scheme applied to a case-study 6-bit 1 GS/s ADC are shown and validate the proposed test methodology.
Autors: Santin, E.;Oliveira, L. B.;Nowacki, B.;Goes, J.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jul 2011, volume: 58, issue:7, pages: 1531 - 1541
Publisher: IEEE
 
» A fully on-chip ESD protection UWB-band low noise amplifier using GaAs enhancement-mode dual-gate pHEMT technology
Abstract:
 Highlights: ? We present a novel ESD protected wideband LNA using E-mode pHEMT dual-gate clamps. ? This clamp achieved a low on-state resistance anduniform parasitic capacitance. ? This clamp achieved a HBM ESD test more than+2.5kV and -2kV HBM ESDvoltage. ? The incorporated clamps use the fewer diodes than the conventional diode stacks.

Autors: This paper presents the development of a novel ESD protected wideband low noise amplifier (LNA) using enhancement-mode (E-mode) pHEMT dual-gate clamps. The proposed novel clamp possesses a low on-state resistance, uniform parasitic capacitance, and f
Appeared in: Microelectronics Reliability
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A Fully-Integrated, Short-Range, Low Data Rate FM-UWB Transmitter in 90 nm CMOS
Abstract:
This paper presents a fully-integrated 3–5 GHz-band FM-UWB transmitter implemented in 90 nm bulk CMOS. The front-end consists of an RF current-controlled oscillator (RF-ICO) and class-AB power amplifier. Transmit data modulates a sub-carrier oscillator. The 2-FSK modulated output is amplified by a transconductor, and directly modulates the RF-ICO tune input. A successive approximation register (SAR) algorithm and on-chip all-digital frequency-locked loop (FLL) calibrate the carrier and sub-carrier frequencies. All voltage and current references required by the transmitter are included on-chip. The 0.2 0.5 mm active area transmitter consumes 900 W from a 1 V supply. Energy efficiency of the transmitter is 9 nJ/bit running continuously at 100 kbits/s.
Autors: Saputra, N.;Long, J. R.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2011, volume: 46, issue:7, pages: 1627 - 1635
Publisher: IEEE
 
» A General Convergence Result for Particle Filtering
Abstract:
The particle filter has become an important tool in solving nonlinear filtering problems for dynamic systems. This correspondence extends our recent work, where we proved that the particle filter converges for unbounded functions, using -convergence. More specifically, the present contribution is that we prove that the particle filter converge for unbounded functions in the sense of -convergence, for an arbitrary .
Autors: Hu, X.-L.;Schon, T. B.;Ljung, L.;
Appeared in: IEEE Transactions on Signal Processing
Publication date: Jul 2011, volume: 59, issue:7, pages: 3424 - 3429
Publisher: IEEE
 
» A General Framework to Perform the MAX/MIN Operations in Parameterized Statistical Timing Analysis Using Information Theoretic Concepts
Abstract:
As integrated circuit technologies are scaled down to the nanometer regime, process variations have increasing impact on circuit timing. To address this issue, parameterized statistical static timing analysis (SSTA) has been recently developed. In parameterized SSTA, process variations are represented as random variables (RVs) and timing quantities (delays and others) are expressed as functions of these variables. Most of the existing algorithms to compute the MAX/MIN operations in parameterized SSTA model spatial and path-based statistical dependencies of variation sources using the second-order statistical methods. Unfortunately, such methods have limited capabilities to determine statistical relations between RVs. This results in decreasing the accuracy of the MAX/MIN algorithms, especially when process parameters follow non-Gaussian probability density functions (PDFs) and/or affect timing quantities nonlinearly. In contrast, information theory (IT) provides powerful techniques that allow a natural PDF-based analysis of probabilistic relations between RVs. So, in this paper, we propose a new framework to perform the MAX/MIN operations based on IT concepts. The key ideas behind our framework are: 1) exploiting information entropy to measure unconditional equivalence between an actual MAX/MIN output and its approximate parameterized representation, and 2) using mutual information to measure equivalence of actual and parameterized MAX/MIN outputs from the viewpoint of their statistical relations to process variations. We construct a general IT-based MAX/MIN algorithm that allows a number of particular realizations accounting for statistical properties of parameterized RVs. The experimental results validate the correctness and demonstrate a high accuracy of the new IT-based approach to compute the MAX/MIN.
Autors: Rubanov, N.;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jul 2011, volume: 30, issue:7, pages: 1011 - 1019
Publisher: IEEE
 
» A green-switch controller IC for cascade buck-boost converter with seamless transition over entire input and load range?
Abstract:
 Highlights: ? We design a multi-mode controlled 4-switch cascade buck-boost controller IC. ? Mode transition is realized by identifying duty ratio in current control method. ? Three-phase transition strategy increases line regulation and reduces output ripple. ? Burst mode increases the conversion efficiency under light load condition. ? We do an elaborate circuit design and rigorous stability analysis.

Autors: To raise the utilization ratio of lithium-ion battery in portable devices, a novel green-switch controller IC is proposed to constitute a 4-switch cascade buck-boost prototype, which is capable of outputting non-inverting step down and step up voltag
Appeared in: Microelectronics Journal
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A Growing Digital Divide: Internet Freedom and the Negative Impact of Command-and-Control Networking
Abstract:
There is a growing consensus that communications is a fundamental right. However, achieving digital equality in the broadband age has become considerably more complex than just universal access. This article offers a more nuanced perspective on the widening digital divide that's centered on a user's utility of a broadband connection and outlines networking technologies that place control in users' hands.
Autors: Meinrath, Sascha D.;Losey, James;Lennett, Benjamin;
Appeared in: IEEE Internet Computing
Publication date: Jul 2011, volume: 15, issue:4, pages: 75 - 79
Publisher: IEEE
 
» A Hardware Implementation of a Run-Time Scheduler for Reconfigurable Systems
Abstract:
New generation embedded systems demand high performance, efficiency, and flexibility. Reconfigurable hardware can provide all these features. However, the costly reconfiguration process and the lack of management support have prevented a broader use of these resources. To solve these issues we have developed a scheduler that deals with task-graphs at run-time, steering its execution in the reconfigurable resources while carrying out both prefetch and replacement techniques that cooperate to hide most of the reconfiguration delays. In our scheduling environment, task-graphs are analyzed at design-time to extract useful information. This information is used at run-time to obtain near-optimal schedules, escaping from local-optimum decisions, while only carrying out simple computations. Moreover, we have developed a hardware implementation of the scheduler that applies all the optimization techniques while introducing a delay of only a few clock cycles. In the experiments our scheduler clearly outperforms conventional run-time schedulers based on as-soon-as-possible techniques. In addition, our replacement policy, specially designed for reconfigurable systems, achieves almost optimal results both regarding reuse and performance.
Autors: Clemente, J. A.;Resano, J.;Gonzalez, C.;Mozos, D.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jul 2011, volume: 19, issue:7, pages: 1263 - 1276
Publisher: IEEE
 
» A hierarchical Path Computation Element (PCE)-based k-random-paths routing algorithm in multi-domain WDM networks
Abstract:
 Highlights: ? In this study an interdomain routing algorithm is proposed for multidomain WDM mesh networks. ? The proposed algorithm introduces a k random path strategy in the parent PCE to adjust the algorithm optimization level. ? The proposed algorithm outperforms previous schemes in terms of blocking probability and resource utilization while not increasing the PCEP signaling overhead. ? The result of the proposed algorithm approximates the global optimal path when load balance is considered.

Autors: We propose an inter-domain routing algorithm for multi-domain wavelength-division multiplexing (WDM) mesh networks. On the basis of the hierarchical Path Computation Element (PCE) architecture, the proposed algorithm introduces a k random path strate
Appeared in: Optical Switching and Networking
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A High Precision Fast Locking Arbitrary Duty Cycle Clock Synchronization Circuit
Abstract:
This study proposes a high precision fast locking arbitrary duty cycle clock synchronization (HPCS) circuit. This HPCS is capable of synchronizing the external clock and the internal clock in three clock cycles. By using three innovative techniques, the proposed HPCS can also reduce the clock skew between the external clock and the internal clock in a chip. First, by modifying the mirror control circuit, the HPCS operates correctly with an arbitrary duty cycle (25%–75%) clock signal. Second, the HPCS works precisely and ignores the effect of output load changes by moving the measurement delay line beyond the output driver. Finally, the HPCS can enhance the resolution between the external clock and internal clock with a fine tuning structure. After phase locking, the maximum static phase error is less than 20 ps. The proposed chip is fabricated in a TSMC 130-nm CMOS process, and has an operating frequency range from 300 to 600 MHz. At 600 MHz, the power consumption and rms jitter are 2.4 mW and 3.06 ps, respectively. The active area of this chip is 0.3 0.13 mm .
Autors: Cheng, K. -H.;Hong, K. -W.;Chen, C. -H.;Liu, J. -C.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jul 2011, volume: 19, issue:7, pages: 1218 - 1228
Publisher: IEEE
 
» A high speed, fully digital IC random number generator
Abstract:
System-on-a-chip solutions require hardware based integrated circuit random number generators for trustworthy transmission of information. This paper presents, a fully digital, high speed ASIC random number generator based on ring oscillators. Prototypes have been designed and fabricated in HHNEC's 0.25?m eFlash process with a supply voltage of 2.5V. The circuit occupies 0.052mm2 and dissipates 0.095W of power. IC design level experiences, measurements, analysis of measurements and statistical test results are also demonstrated. Instead of resilient function, employed in the previous ring oscillators based design, which decreases the throughput by a factor of 16, we propose to use only a simple...
Autors: Ülkühan, Güler , Salih, Ergün
Appeared in: AEU - International Journal of Electronics and Communications
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A high-speed four-phase clock generator for low-power on-chip SerDes applications
Abstract:
 Highlights: ? Four-phase clock generators are employed for low-noise and low-power applications. ? Four-phased clocks duty cycle has to be 50%. ? The clocks must show a 90° phase shift between them. ? Low-power, low-area, high-speed and full output swing four-phase clock generators can be constructed with differential prescalers and duty cycle adjusters.

Autors: In this work we present a low-power, low-area and high-speed fully CMOS quadrature clock generator for on-chip SerDes applications. The device utilizes a couple of differential prescalers for high speed frequency division and four duty cycle adjuster
Appeared in: Microelectronics Journal
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A High-Voltage Test Bed for the Evaluation of High-Voltage Dividers for Pulsed Applications
Abstract:
The design, evaluation, and commissioning of a high-voltage reference test bed for pulsed applications to be used in the precision testing of high-voltage dividers is described. The test bed is composed of a pulsed power supply, a reference divider based on compressed-gas capacitor technology, and an acquisition system that makes use of the fast measurement capabilities of the HP3458 digital voltmeter. The results of the evaluation of the reference system are presented.
Autors: Bastos, M.C.;Hammarquist, M.;Bergman, A.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jul 2011, volume: 60, issue:7, pages: 2462 - 2468
Publisher: IEEE
 
» A Hybrid Framework for Fault Detection, Classification, and Location—Part I: Concept, Structure, and Methodology
Abstract:
Bridging the gap between the theoretical modeling and the practical implementation is always essential for fault detection, classification, and location methods in a power transmission-line network. In this paper, a novel hybrid framework that is able to rapidly detect and locate a fault on power transmission lines is presented. The proposed algorithm presents a fault discrimination method based on the three-phase current and voltage waveforms measured when fault events occur in the power transmission-line network. Negative-sequence components of the three-phase current and voltage quantities are applied to achieve fast online fault detection. Subsequently, the fault detection method triggers the fault classification and fault-location methods to become active. A variety of methods—including multilevel wavelet transform, principal component analysis, support vector machines, and adaptive structure neural networks—are incorporated into the framework to identify fault type and location at the same time. This paper lays out the fundamental concept of the proposed framework and introduces the methodology of the analytical techniques, a pattern-recognition approach via neural networks and a joint decision-making mechanism. Using a well-trained framework, the tasks of fault detection, classification, and location are accomplished in 1.28 cycles, significantly shorter than the critical fault clearing time.
Autors: Jiang, J.-A.;Chuang, C.-L.;Wang, Y.-C.;Hung, C.-H.;Wang, J.-Y.;Lee, C.-H.;Hsiao, Y.-T.;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Jul 2011, volume: 26, issue:3, pages: 1988 - 1998
Publisher: IEEE
 
» A Kalman-Yakubovich-Popov-type lemma for systems with certain state-dependent constraints?
Abstract:
In this note, a result is presented that may be considered an extension of the classical Kalman-Yakubovich-Popov (KYP) lemma. Motivated by problems in the design of switched systems, we wish to infer the existence of a quadratic Lyapunov function (QLF) for a nonlinear system in the case where a matrix defining one system is a rank-1 perturbation of the other and where switching between the systems is orchestrated according to a conic partitioning of the state space . We show that a necessary and sufficient condition for the existence of a QLF reduces to checking a single constraint on a...
Autors: Christopher K., King , Wynita M., Griggs , Robert N., Shorten
Appeared in: Automatica
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A Kullback–Leibler Divergence Approach to Blind Image Restoration
Abstract:
A new algorithm for maximum-likelihood blind image restoration is presented in this paper. It is obtained by modeling the original image and the additive noise as multivariate Gaussian processes with unknown covariance matrices. The blurring process is specified by its point spread function, which is also unknown. Estimations of the original image and the blur are derived by alternating minimization of the Kullback–Leibler divergence between a model family of probability distributions defined using the linear image degradation model and a desired family of probability distributions constrained to be concentrated on the observed data. The algorithm presents the advantage to provide closed form expressions for the parameters to be updated and to converge only after few iterations. A simulation example that illustrates the effectiveness of the proposed algorithm is presented.
Autors: Seghouane, A.-K.;
Appeared in: IEEE Transactions on Image Processing
Publication date: Jul 2011, volume: 20, issue:7, pages: 2078 - 2083
Publisher: IEEE
 
» A Level Set Method for Image Segmentation in the Presence of Intensity Inhomogeneities With Application to MRI
Abstract:
Intensity inhomogeneity often occurs in real-world images, which presents a considerable challenge in image segmentation. The most widely used image segmentation algorithms are region-based and typically rely on the homogeneity of the image intensities in the regions of interest, which often fail to provide accurate segmentation results due to the intensity inhomogeneity. This paper proposes a novel region-based method for image segmentation, which is able to deal with intensity inhomogeneities in the segmentation. First, based on the model of images with intensity inhomogeneities, we derive a local intensity clustering property of the image intensities, and define a local clustering criterion function for the image intensities in a neighborhood of each point. This local clustering criterion function is then integrated with respect to the neighborhood center to give a global criterion of image segmentation. In a level set formulation, this criterion defines an energy in terms of the level set functions that represent a partition of the image domain and a bias field that accounts for the intensity inhomogeneity of the image. Therefore, by minimizing this energy, our method is able to simultaneously segment the image and estimate the bias field, and the estimated bias field can be used for intensity inhomogeneity correction (or bias correction). Our method has been validated on synthetic images and real images of various modalities, with desirable performance in the presence of intensity inhomogeneities. Experiments show that our method is more robust to initialization, faster and more accurate than the well-known piecewise smooth model. As an application, our method has been used for segmentation and bias correction of magnetic resonance (MR) images with promising results.
Autors: Li, C.;Huang, R.;Ding, Z.;Gatenby, J. C.;Metaxas, D. N.;Gore, J. C.;
Appeared in: IEEE Transactions on Image Processing
Publication date: Jul 2011, volume: 20, issue:7, pages: 2007 - 2016
Publisher: IEEE
 
» A linear-high range output power control technique for cascode power amplifiers
Abstract:
 Highlights: ? In this paper, a linear high-range power control technique is presented. ? The technique is suitable for casecode power amplifiers. ? Linear power control range of the technique is 34.5dBm. ? The input dynamic range is 0.373 and less than the conventional techniques. ? AM-PM distortion of the technique is 43°.

Autors: In this paper a new linear power control technique is presented to control the output power of cascode power amplifiers. Using this technique the output power of power amplifier can be controlled from the maximum output power to -136dBm, continuously
Appeared in: Microelectronics Journal
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A Look at Electrical Hazards [Standards]
Abstract:
Electricity is a valuable asset for society. It can be naturally generated by the differences in temperatures or wind action on clouds, by the movement of air over conductive wires, by sliding a conductive body across an isolated/nonconductive surface, and displays its presence by static or lightning discharges. It can also be generated by man-made electromechanical machinery driven by water or air flow, photosynthesis devices, or fuel cells, and its presence is displayed by providing light for security in the dark, heat for comfort in the cold, or movement for people to work or facilitate production in the workplace.
Autors: Mcclung, B.;
Appeared in: IEEE Industry Applications Magazine
Publication date: Jul 2011, volume: 17, issue:4, pages: 76 - 77
Publisher: IEEE
 
» A Low Phase Noise, Wideband and Compact CMOS PLL for Use in a Heterodyne 802.15.3c Transceiver
Abstract:
A low phase noise, wideband, mm-wave, integer-N PLL that is capable of supporting an 802.15.3c heterodyne transceiver is reported. The PLL can generate 6 equally spaced tones from 43.2 GHz to 51.84 GHz, which is suitable for a heterodyne architecture with . Phase noise is measured directly at the frequency and is better than 97.5 dBc/Hz@1 MHz across the entire band. The reported frequency synthesizer is smaller, exhibits less phase noise, and consumes less power than prior art. In addition, the tone corresponds to the fundamental of the VCO as opposed to a higher harmonic.
Autors: Murphy, D.;Gu, Q. J.;Wu, Y.-C.;Jian, H.-Y.;Xu, Z.;Tang, A.;Wang, F.;Chang, M.-C. F.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2011, volume: 46, issue:7, pages: 1606 - 1617
Publisher: IEEE
 
» A Low Power Impulse Radio Design for Body-Area-Networks
Abstract:
This paper presents a low power radio design tailored to the short distance, low data rate application of body area networks. In our analysis we consider a comparison between traditional continuous wave radios and ultra wide band impulse radios for this application space. We analyze the energy/bit requirement for each of the architectures and discuss how a duty-cycled radio is better suited to low data rate applications due to practical design considerations. As a proof-of-concept we present the design and measured results of a duty-cycled, noncoherent impulse radio transceiver. The designed transceiver was measured to consume only 19 at a data-rate of 100 kbps. The design gives a BER of and works for a range of 2.5 m at an average Rx-sensitivity of . The designed transceiver enables both OOK and BPSK schemes and can be configured to use a pseudocoherent self-correlated signature detection and generation mechanism. This added functionality helps distinguish different types of pulses such as timing and data-pulses in real time. The transceiver was designed in a 90 nm CMOS process and occupies 2.3 area.
Autors: Dokania, R. K.;Wang, X. Y.;Tallur, S. G.;Apsel, A. B.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jul 2011, volume: 58, issue:7, pages: 1458 - 1469
Publisher: IEEE
 
» A Low Repetition Rate All-Active Monolithic Passively Mode-Locked Quantum-Dot Laser
Abstract:
A passively mode-locked laser with a 2.1-GHz fundamental repetition rate is demonstrated using a 20-mm-long monolithic two-section quantum-dot laser. A pulsewidth as short as 15.4 ps was measured using a high-speed sampling scope. The product of the peak power and average power in this laser is treated theoretically and shown experimentally to nearly double by roughly quadrupling the cavity length.Pub _bookmark Command="[Quick Mark]"
Autors: Li, Y.;Breivik, M.;Feng, C.-Y.;Fimland, B.-O.;Lester, L. F.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jul 2011, volume: 23, issue:14, pages: 1019 - 1021
Publisher: IEEE
 
» A Low-Cost Solution for Deploying Processor Cores in Harsh Environments
Abstract:
Nowadays, a number of processor cores are available, either as soft intellectual property (IP) cores or as hard macros that can be employed in developing new systems on a chip. Developers of applications targeting harsh environments like the atmospheric radiation environment or the space radiation environment may benefit from the computing power of processor cores, provided that suitable techniques are available for guaranteeing their correct operations in presence of the ionizing radiation that abounds in such environments. In this paper, we describe a design flow and hardware/software architecture to successfully deploy processor IP cores in harsh environments. Experimental data are provided that confirm the robustness of the presented architecture with respect to transient errors induced by radiation and suggest the possibility of employing such architectures in deep-space exploration missions.
Autors: Violante, M.;Meinhardt, C.;Reis, R.;Reorda, M.S.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jul 2011, volume: 58, issue:7, pages: 2617 - 2626
Publisher: IEEE
 
» A Low-Power and Flexible Energy Detection IR-UWB Receiver for RFID and Wireless Sensor Networks
Abstract:
This paper presents an energy detection Impulse Radio Ultra-Wideband (IR-UWB) receiver for Radio Frequency Identification (RFID) and Wireless Sensor Networks (WSN) applications. An Application-Specific Integrated Circuit (ASIC) consisting of a 3–5 GHz analog front-end, a timing circuit and a high speed baseband controller is implemented in a 90 nm standard CMOS technology. A Field-Programmable Gate Array (FPGA) is employed as a reconfigurable back-end, enabling adaptive baseband algorithms and ranging estimations. The proposed architecture is featured by high flexibility that adopts a wide range of pulse rate (512 kHz–33 MHz), processing gain (0–18 dB), correlation schemes, synchronization algorithms, and modulation schemes (PPM/OOK). The receiver prototype was fabricated and measured. The power consumption of the ASIC is 16.3 mW at 1 V power supply, which promises a minimal energy consumption of 0.5 nJ/bit. The whole link is evaluated together with a UWB RFID tag. Bit error rate (BER) measurement displays a sensitivity of 79 dBm at 10 Mb/s with achieved by the proposed receiver, corresponding to an operation distance over 10 meters under the FCC regulation.
Autors: Zou, Z.;Mendoza, D. S.;Wang, P.;Zhou, Q.;Mao, J.;Jonsson, F.;Tenhunen, H.;Zheng, L.-R.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jul 2011, volume: 58, issue:7, pages: 1470 - 1482
Publisher: IEEE
 
» A Low-Power High-PSRR Clock-Free Current-Controlled Class-D Audio Amplifier
Abstract:
A low power, high PSRR, clock-free, current-controlled class-D audio power amplifier is presented. The proposed audio amplifier utilizes integral sliding mode control (ISMC) to ensure robust operation and to minimize the steady-state error. This architecture has two feedback loops: an outer voltage loop that minimizes the voltage error between the input and output audio signals, and an inner current loop that measures the inductor current to track the input signal accurately. The proposed amplifier achieves up to 82 dB of power supply rejection ratio (PSRR), more than 90 dB of signal-to-noise (SNR) ratio over the entire audio band, and total harmonic distortion plus noise (THD+N) as low as 0.02%. A power-supply-induced intermodulation distortion (PS-IMD) of approximately 90 dBc was measured for an input voltage signal of 2 at 1 kHz and a sinusoidal power-supply ripple of 300 mV at 217 Hz superimposed on the DC level. The IC prototype's controller consumes 30% less power than those of recently published works. The audio amplifier operates with a 2.7-V single voltage supply and delivers a maximum output power of 410 mW with 84% peak efficiency ( ) into an 8 speaker. It was fabricated using 0.5 m CMOS standard technology, and occupies a total active area of 1.65 mm .
Autors: Torres, J.;Colli-Menchi, A.;Rojas-Gonzalez, M. A.;Sanchez-Sinencio, E.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jul 2011, volume: 46, issue:7, pages: 1553 - 1561
Publisher: IEEE
 
» A Magnetic Flower State-Based Memory Cell
Abstract:
In an elliptical magnetic dot two vortices and a flower state configuration can be accommodated at remanence. We show that a two-fold degeneracy in the position of the flower state can be geometrically introduced and exploited for solid state data storage. Switching between two, energetically-equivalent, magnetic configurations is obtained by injecting a perpendicular electric current. Switching currents of the order of and high thermal stability are demonstrated by micromagnetic simulations. This system can be used as a bit-cell for magnetic solid state data storage. The low value of the switching current and the high thermal stability allow direct integration with the current complementary metal oxide semiconductor technology.
Autors: Wang, N.;Wang, X. L.;Ruotolo, A.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2011, volume: 47, issue:7, pages: 1970 - 1973
Publisher: IEEE
 
» A Magnetoelectric Composite Energy Harvester and Power Management Circuit
Abstract:
This paper proposes a ferro-nickel (Fe-Ni)/PZT H-type fork magnetoelectric (ME) composite structure and an energy management circuit for ME energy harvesting. The resonant fork composite structure with a high Q value shows a higher ME voltage coefficient and a stronger power coefficient compared with the conventional rectangular composite structure. The resonant fork composite structure can obtain an output power of 61.64 μW at an ac magnetic field of 0.2 Oe. The ME sensitivity of the fork structure reaches 11 V/Oe. For weak magnetic-field environment, an active magnetic generator and a magnetic coil antenna underground are used for producing an ac magnetic field of 0.2-1 Oe at a distance of 25-50 m. A management circuit of the power supply with matching circuit, energy-storage circuit, and instantaneous-discharge circuit is developed suitable for weak electromagnetic energy harvesting. The management circuit can continuously accumulate weak energy from the fork composite structure for a long period and provide a high-power output in a very short cycle. While the voltage across the storage supercapacitor is over 0.36 V, the instantaneous-discharge circuit can drive a wireless sensor network node with an output power of 75 mW at a distance of over 60 m.
Autors: Ping Li;Yumei Wen;Chaobo Jia;Xinshen Li;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jul 2011, volume: 58, issue:7, pages: 2944 - 2951
Publisher: IEEE
 
» A Maximum NEC Criterion for Compton Collimation to Accurately Identify True Coincidences in PET
Abstract:
In this work, we propose a new method to increase the accuracy of identifying true coincidence events for positron emission tomography (PET). This approach requires 3-D detectors with the ability to position each photon interaction in multi-interaction photon events. When multiple interactions occur in the detector, the incident direction of the photon can be estimated using the Compton scatter kinematics (Compton Collimation). If the difference between the estimated incident direction of the photon relative to a second, coincident photon lies within a certain angular range around colinearity, the line of response between the two photons is identified as a true coincidence and used for image reconstruction. We present an algorithm for choosing the incident photon direction window threshold that maximizes the noise equivalent counts of the PET system. For simulated data, the direction window removed 56%–67% of random coincidences while retaining of true coincidences from image reconstruction as well as accurately extracted 70% of true coincidences from multiple coincidences.
Autors: Chinn, G.;Levin, C. S.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jul 2011, volume: 30, issue:7, pages: 1341 - 1352
Publisher: IEEE
 
» A method to analyze the impact of fast-recovering NBTI degradation on the stability of large-scale SRAM arrays
Abstract:
This paper presents stability analysis of large-scale SRAM arrays directly after terminating NBTI stress. While the impact of static NBTI is well examined, the fast-recovering component was not yet measured on SRAM arrays. The novel method presented here analyzes the flipping of cells directly after the supply voltage was lowered to a specific value where the structure is most sensitive for NBTI induced cell flips. Thus, read margin criterion is used to characterize the decreasing cell stability due to NBTI degradation with a resolution down to 1ms. Applying this method, the impact of static and dynamic NBTI is measured on...
Autors: Stefan, Drapatz , Karl, Hofmann , Georg, Georgakos , Doris, Schmitt-Landsiedel
Appeared in: Solid-State Electronics
Publication date: Jul 2011
Publisher: Elsevier B.V.
 
» A Metric for Performance Evaluation of Multi-Target Tracking Algorithms
Abstract:
Performance evaluation of multi-target tracking algorithms is of great practical importance in the design, parameter optimization and comparison of tracking systems. The goal of performance evaluation is to measure the distance between two sets of tracks: the ground truth tracks and the set of estimated tracks. This paper proposes a mathematically rigorous metric for this purpose. The basis of the proposed distance measure is the recently formulated consistent metric for performance evaluation of multi-target filters, referred to as the OSPA metric. Multi-target filters sequentially estimate the number of targets and their position in the state space. The OSPA metric is therefore defined on the space of finite sets of vectors. The distinction between filtering and tracking is that tracking algorithms output tracks and a track represents a labeled temporal sequence of state estimates, associated with the same target. The metric proposed in this paper is therefore defined on the space of finite sets of tracks and incorporates the labeling error. Numerical examples demonstrate that the proposed metric behaves in a manner consistent with our expectations.
Autors: Ristic, B.;Vo, B.-N.;Clark, D.;Vo, B.-T.;
Appeared in: IEEE Transactions on Signal Processing
Publication date: Jul 2011, volume: 59, issue:7, pages: 3452 - 3457
Publisher: IEEE
 
» A Microionizer for Portable Mass Spectrometers Using Double-Gated Isolated Vertically Aligned Carbon Nanofiber Arrays
Abstract:
We report a gas ionizer based on arrays of microfabricated double-gated isolated vertically aligned carbon nanofibers (VA-CNFs) for application in low-power portable mass spectrometers. Field-emitted electrons from VA-CNFs are accelerated to high energy and subsequently collide with neutral gas molecules, leading to ionization/fragmentation of the molecules. Double-gated field-emitter arrays with isolated VA-CNF tips were fabricated using a photoresist planarization technique. Two types of devices were fabricated and characterized. The first type of device has the emitter tip in the same plane as the extraction gate, and the second type of device has the emitter tip 900 nm below the extraction gate. All devices were made using a process that results in gate and focus diameters of 1.7 and 4.2 , respectively. When operated as a field-emitted electron impact ionizer (EII), for the same ion current, the ionization efficiency (ratio of ions to emitted electrons) increased from 0.005 to 0.05 as the pressure is increased between and torr. In comparison with EIIs based on thermionic electron sources, the power dissipation reduced from 1 W to 100 mW.
Autors: Chen, L.-Y.;Velasquez-Garcia, L. F.;Wang, X.;Teo, K.;Akinwande, A. I.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jul 2011, volume: 58, issue:7, pages: 2149 - 2158
Publisher: IEEE
 
» A Model Selection Method for Nonlinear System Identification Based fMRI Effective Connectivity Analysis
Abstract:
In this paper a model selection algorithm for a nonlinear system identification method is proposed to study functional magnetic resonance imaging (fMRI) effective connectivity. Unlike most other methods, this method does not need a pre-defined structure/model for effective connectivity analysis. Instead, it relies on selecting significant nonlinear or linear covariates for the differential equations to describe the mapping relationship between brain output (fMRI response) and input (experiment design). These covariates, as well as their coefficients, are estimated based on a least angle regression (LARS) method. In the implementation of the LARS method, Akaike's information criterion corrected (AICc) algorithm and the leave-one-out (LOO) cross-validation method were employed and compared for model selection. Simulation comparison between the dynamic causal model (DCM), nonlinear identification method, and model selection method for modelling the single-input-single-output (SISO) and multiple-input multiple-output (MIMO) systems were conducted. Results show that the LARS model selection method is faster than DCM and achieves a compact and economic nonlinear model simultaneously. To verify the efficacy of the proposed approach, an analysis of the dorsal and ventral visual pathway networks was carried out based on three real datasets. The results show that LARS can be used for model selection in an fMRI effective connectivity study with phase-encoded, standard block, and random block designs. It is also shown that the LOO cross-validation method for nonlinear model selection has less residual sum squares than the AICc algorithm for the study.
Autors: Li, X.;Coyle, D.;Maguire, L.;McGinnity, T. M.;Benali, H.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jul 2011, volume: 30, issue:7, pages: 1365 - 1380
Publisher: IEEE
 

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