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IEEE International Conference on Acoustics, Speech, and Signal Processing

作者： Stephen D. Voran Institute for Telecommunication Sciences

ISBN: (纸本)9781479903573

The lossless compression algorithm specified in ITU-T Recommen-dation G.711.0 provides bit-exact G.711 speech coding at reduced bit-rates. We introduce two Look-Up coders (LUCs) that also offer bit-exact G.711 speech coding at reduced rates but the LUCs do not use arithmetic operations and hence eliminate the need for a processor. Instead they read in eight G.711 symbols, reinterpret those 64 bits to form eight new symbols that carry temporal information, then look up Huffman codes for those new symbols. When compared to G.711.0, LUC rates are 9% to 40% higher and they require 2 to 8 kB additional ROM, but LUCs eliminate about one million weighted arithmetic operations per second. LUCs reduce the 8 b/smpl G.711 rate to 3.8 to 6.7 b/smpl, depending on speech and noise levels.

关键词： G.711 G.711.0 Lossless compression PCM Speech coding speech coding lossless compression pulse code modulation Speech Huffman codes Signs and symbols arithmetic operation time information

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State Estimation for PEM Fuel Cell Systems with Time Delay by an Unscented Kalman Filter and Predictor Strategy

State Estimation for PEM Fuel Cell Systems with Time Delay b...

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Mediterranean Conference on Control & Automation

作者： Martin Schultzc Joachim Horn Institute of Control Engineering Helmut-Schmidt-University Hamburg

ISBN: (纸本)9781479909964

Polymer electrolyte membrane (PEM) fuel cell systems are investigated as replacement for auxiliary power units (APU) that are currently used for electrical power generation on aircraft. PEM fuel cells are highly efficient energy converters and provide electrical energy, cathode exhaust gas with low oxygen concentration and water. The system investigated is intended for generation of oxygen depleted cathode exhaust air (ODA) on aircraft with ODA-gas having a low oxygen concentration. Measurement of ODA-gas mass flow and oxygen content introduces a significant time delay. For state estimation a reduced order nonlinear model comprising the fuel cell stack, cooling system and cathode exhaust gas dehumidifying system has been derived. In a three steps state estimation strategy involving Unscented Kalman filtering combined with a prediction compensating for the significant time delay the actual system state is estimated. The strategy is implemented in Matlab/Simulink and has been applied successfully. Experimental results are shown.

关键词： State estimation time delay oxygen concentration Power production fuel cell power systems Energy converters mucin 1 pulse code modulation Aircraft MASS FLOW fuel cell stack Polymer electrolyte membrane fuel cells Cathodes oxygen content

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Failure localization methods for System-on-Chip (SoC) using Photon Emission Microscopy

Failure localization methods for System-on-Chip (SoC) using ...

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IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits

作者： Y. Chen H. Chen X. W. Zhang P. Lai Science and Technology on Reliability Physics and Application of Electronic Component Laboratory The Fifth Electronics Research Institute of Ministry of Industry and Information Technology

ISBN: (纸本)9781479904792

System-on-Chip (SoC) is a major revolution in IC design where the whole functionality of a system is placed on a single chip. Its advantages include high performance, shorter design cycle time and space efficiency. But due to the circuit complexity, the high pin counts and ever increasing operating frequencies, System-on-Chip (SoC) devices drive the most challenging requirements for failure localization and mechanism analysis. PEM (Photon Emission Microscopy) analysis is important for failure analysis as they can help to locate the failed device directly or point out the analysis direction. This paper presents the failure localization method for System-on-Chip (SoC) using Photon Emission Microscope (PEM) and gives several successful failure analysis cases using PEM locating the failure site and FIB (Focused Ion Beam) and SEM (Scanning electronic Microscope) analyzing the failure mechanism.

关键词： system-on-chip Photon emission mucin 1 pulse code modulation integrated circuit design FAILURE ANALYSIS circuit complexity Failure mechanisms fibrillarin Microscopy

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Properties of nanoporous carbon material with one-dimensional conductivity

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SOLID FUEL CHEMISTRY 2012年第5期46卷 297-304页

作者： Samarov, A. V. Barnakov, Ch. N. Kozlov, A. P. Ismagilov, Z. R. Russian Acad Sci Inst Coal Chem & Mat Sci Siberian Branch Kemerovo 650099 Russia

The nanoporous carbon material (PCM) prepared from petroleum coke or organic compounds that simulate the structure of coke can possess both one-dimensional and three-dimensional conductivity, which is described by the Mott law. It is proposed to consider these materials as two different PCMs with different conductivity, which has an effect on the properties of catalysts, for example, in the cathodes of solid polymer fuel cells and in the production of an anode material and the nanoparticles of 3d metals (iron, cobalt, and nickel), when PCMs are used as the supports of catalysts (or substrates).

关键词： one-dimensional conductivity carbonaceous materials Catalysts Coke negative electrode material Petroleum coke pulse code modulation Cathodes conductivity organic compounds Nickel fuel batteries

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Uncertainty and sensitivity analysis of properties of phase change micro/nanoparticles for thermal protection during cryosurgery

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FORSCHUNG IM INGENIEURWESEN-ENGINEERING RESEARCH 2012年第1-2期76卷 41-50页

作者： Lv, Yonggang Zou, Yang Yang, Li Chongqing Univ Project Lab Biomech & Tissue Repair 111 Bioengn Coll Chongqing 400044 Peoples R China Chongqing Univ Minist Educ Bioengn Coll Key Lab Biorheol Sci & Technol Chongqing 400044 Peoples R China

Based on our previous study which tested the feasibility of protecting the healthy tissue around the cancerous tissue during cryosurgery by microencapsulated phase change materials (PCMs) with large latent heat and low thermal conductivity, uncertainties and sensitivities for thermal protection efficiency caused by the deviations of the PCM properties' values, the PCMs concentration and the distance between the PCMs domain and the tumor domain were further investigated in this study. The preliminary results showed that the radius of the micro/nano PCM particle, the upper and lower phase transition temperatures of the PCM and the distance between the PCMs domain and the tumor domain should be accurately measured before performing thermal protection by PCMs during cryosurgery. Less than 20 % deviations of the heat capacities of solid and liquid PCM almost had no obvious influence on the thermal protection efficiency. The results obtained in this study will further help us to optimize the protection protocol by PCMs before performing cryosurgery.

关键词： Phase transition temperature microencapsulated phase change materials Phase transtormations thermal protection Sensitivity analysis Cryosurgery Heat capacity pulse code modulation

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A Recurrent Neural Approach for Modeling Non-Reproducible Behavior of PEM Fuel Cell Stacks

A Recurrent Neural Approach for Modeling Non-Reproducible Be...

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IEEE International Conference on Industrial Technology

作者： Francisco da Costa Lopes Edson H. Watanabe Luis Guilherme B. Rolim Department of Special Technologies CEPEL - Electric Energy Research Center Rio de Janeiro Brazil Department of Electrical Engineering - COPPE Universidade Federal do Rio de Janeiro Rio de Janeiro Brazil

ISBN: (纸本)9781467345675

This work presents a recurrent neural model for PEM fuel cell stacks based on NARX and NOE neural structures. The practical difficulties to employ electrochemical models and the causes of the odd behavior observed in some PEM stacks are discussed. The model developed predicts the terminal voltage of a stack even in the situation where it presents a non-reproducible behavior, such as unexpected voltage fluctuations. The predictive capacity of the model is evaluated in two different scenarios, showing good agreement with the measured data.

关键词： fuel cell stack mucin 1 pulse code modulation chimneys Inappropriate behavior fuel batteries Voltage fluctuations terminal voltage

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Multi-physics Model for Regenerative PEM Fuel Cell Energy Storage

Multi-physics Model for Regenerative PEM Fuel Cell Energy St...

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IEEE International Conference on Industrial Technology

作者： Piergiorgio Alotto Massimo Guarnieri Dipartimento di Ingegneria Industriale Università di Padova Padua Italy

ISBN: (纸本)9781467345675

Electrochemical storage (ECES) systems are expected to become increasingly important and widespread in the coming years, with the expansion of renewable energy sources, smart grids and electrical vehicles. Special advantages can be provided by those ECESs which can be independently sized in power and stored energy. Some of the most promising technologies of this type are redox flow batteries and fuel cells combined to electrolyzers. Both these technologies are under extensive R&D programs, aimed at improving their performance. As regards the latter, regenerative fuel cells (R-FCs) provide both charge and discharge functions in the same device. This paper presents a unified model able to describe both these operation modes of R-FCs of the PEM (polymer electrolyte membrane) type (R-PEMFC). The model takes into account the dependence of the electrical quantities and parameters on the major physical-chemical variables and can be used to address structural and operational optimizations.

关键词： Regenerative fuel cell electrolyzer PEMFC model PEMEL model hydrogen energy storage electrolyzer energy storage Regenerative fuel cells fuel batteries mucin 1 pulse code modulation electrical quantities REDOX FLOW BATTERIES operation mode Renewable energy renewable energy sources Energy sources

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A Scalable Volume-Confined Phase Change Memory Using Physical Vapor Deposition

A Scalable Volume-Confined Phase Change Memory Using Physica...

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Symposium on VLSI Technology

作者： S. C. Lai S. Kim M. BrightSky Y. Zhu E. Joseph R. Bruce H. Y. Cheng A. Ray S. Raoux J. Y. Wu T. Y. Wang Macronix International Co. Ltd. IBM T. J. Watson Research Center

ISBN: (纸本)9781479916238

To improve writing bandwidth for phase change memory (PCM) volume-confined cells are proposed to reduce the reset current [1,2]. So far, CVD or ALD GST must be used to fill the small hole, with several negative issues. This work proposes and demonstrates a PVD GST volume-confined structure by using an isolation-last process. In our structure, a low aspect ratio (< 1) trench is created and PVD GST is deposited in the bottom and the sidewalls of the trench uniformly, and then covered by SiN. This protects the GST from etching damage and small VC phase change elements can be fabricated. The electrical characteristics show much reduced reset current and good endurance behavior because of the improved heating efficiency and the congruent melting [3] in VC PCM. PVD GST is much more flexible in materials selection and doping, thus has better scalability because of the ideal PC element size match with the selecting device.

关键词： Physical vapor deposition Phase change memory reset current etching damage Materials selection Scalability vapour deposition ELECTRICAL CHARACTERISTICS sin SIDEWALL e-bank vital capacity measurement pulse code modulation TRENCHES

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Control Algorithm Based on an Experimental Approach for PEM Fuel Cell Systems Efficiency Optimization

Control Algorithm Based on an Experimental Approach for PEM ...

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IEEE International Conference on Industrial Technology

作者： K. M. Adegnon K. Agbossou Y. Dube M. Doumbia S. Kelouwani Hydrogen Research Institute and the Department of Electrical and Computer Engineering of Universite du Quebec a Trois-Rivieres Trois-Rivieres Quebec G9A 5H7 Canada Hydrogen Research Institute and the Department of Mechanical Engineering of Universite du Quebec a Trois-Rivieres Trois-Rivieres Quebec G9A 5H7 Canada

ISBN: (纸本)9781467345675

Nowadays, PEM fuel cells are considered as one of the most promising electric energy production technology using hydrogen. For this reason, tracking the efficiency of the PEM fuel cell system is an important research topic. Most of the control algorithms developed to aim this goal are based on models of the PEMFC although to date there is no complete model which takes into account all the phenomenon related to the PEMFC. In this paper, we propose a control algorithm based on an experimental approach which searches for operation parameters (stack temperature, air relative humidity and air stoichiometric ratio) to optimize the efficiency of the PEMFC system. Indeed, an experimental study done beforehand showed that by acting on these parameters, the efficiency of the system which depends highly on the electric power generated by the stack, on the power lost in the auxiliaries and on the hydrogen flow rate, can be optimized. The developed algorithm is based on a local optimization method derived from the line search method. The validity of this method has been proven with different classic functions and the control algorithm has been implemented experimentally in the control interface of our PEMFC system. The experiments analysis showed promising results.

关键词： Efficiency experimental approach global optimization fuel cell line search method Computer algorithms fuel cell power systems Proton exchange membrane fuel cells Global optimization fuel batteries Search methods Control Interface mucin 1 pulse code modulation Flow rates Furnace conveyors OPERATING PARAMETER

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Improving Write Operations in MLC Phase Change Memory

Improving Write Operations in MLC Phase Change Memory

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18th IEEE International Symposium on High-Performance Computer Architecture (HPCA)

作者： Jiang, Lei Zhao, Bo Zhang, Youtao Yang, Jun Childers, Bruce R. Univ Pittsburgh Dept Elect & Comp Engn Pittsburgh PA 15260 USA Univ Pittsburgh Dept Comp Sci Pittsburgh PA USA

ISBN: (纸本)9781467308243;9781467308267

Phase change memory (PCM) recently has emerged as a promising technology to meet the fast growing demand for large capacity memory in modern computer systems. In particular, multi-level cell (MLC) PCM that stores multiple bits in a single cell, offers high density with low per-byte fabrication cost. However, despite many advantages, such as good scalability and low leakage, PCM suffers from exceptionally slow write operations, which makes it challenging to be integrated in the memory hiearchy. In this paper, we propose architectural innovations to improve the access time of MLC PCM. Due to cell process variation, composition fluctuation and the relatively small differences among resistance levels, MLC PCM typically employs an iterative write scheme to achieve precise control, which suffers from large write access latency. To address this issue, we propose write truncation (WT) to reduce the number of write iterations with the assistance of an extra error correction code (ECC). We also propose form switch (FS) to reduce the storage overhead of the ECC. By storing highly compressible lines in SLC form, FS improves read latency as well. Our experimental results show that WT and FS improve the effective write/read latency by 57%/28% respectively, and achieve 26%performance improvement over the state of the art.

关键词： write operation microprocessor logic circuit MLC1 gene Error correction codes pulse code modulation Storage access times Computer systems Phase change memory Elliptic curve cryptography EMERGENCY CONTROL CENTERS accuracy control performance boost Latency capacitor storage

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