检索结果-内蒙古大学图书馆

IEEE International Conference on computer Design: VLSI in computers and Processors, (ICCD)

作者： K. Nabors S. Kim J. White S. Senturia Research Laboratory of Electronics and tlie Microsystems Technology Laboratory Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology USA

Several improvements to the multipole-accelerated 3-D capacitance extraction program previously described are presented. A new adaptive multipole algorithm is given, and a preconditioning strategy for accelerated iterative method convergence is described. Results using these algorithms to compute the capacitance of general three-dimensional structures are presented, and they demonstrate that the modified approach is nearly as accurate as the more standard direct factorization algorithm, and can be as much as two orders of magnitude faster.< >

关键词： Capacitance Conductors Iterative algorithms Contracts laboratories Acceleration Equations Linear systems Circuits Dielectrics

来源：评论

学校读者我要写书评

暂无评论

Comparative simulation of a threshold-based congestion avoidance in broadband isdns

Comparative simulation of a threshold-based congestion avoid...

引用

1991 IEEE Region 10 International Conference on EC3-Energy, computer, Communication and Control Systems, TENCON 1991

作者： Ilyas, Mohammad Rao, Suhas P. Chandra, Vinod Department of Computer Science and Engineering Florida Atlantic University Boca RatonFL33431 United States AT and T Bell Laboratories Crawfords Corner Road HolmdeNJ07733 United States Department of Electrical Engineering Indian Institute of Technology New Delhi 110016 India

ISBN: (纸本)0780305388

We present a comparative simulation of a threshold-based congestion avoidance in Broadband Integrated Services Digital Networks (B-ISDNS). Asynchronous Transfer Mode (ATM) has been recommended by CCITT as one of the most promising means of providing efficient and fast packet switched communication among B-ISDN users. Although B-ISDNS will have an enormous amount of resources offered by fiber optics, congestion may still be experienced due to statistical variations and burstiness in arrival patterns of information traffic. The study presented in this paper deals with congestion avoidance in B-ISDNS and evaluate perfomlance of these techniques by using simulation. Simulation results are presented in the form call blocking probabilities, in comparative terms. © 1991 IEEE.

关键词： Asynchronous transfer mode

来源：评论

学校读者我要写书评

暂无评论

Comparative simulation of high speed unidirectional local area bus networks

Comparative simulation of high speed unidirectional local ar...

引用

1991 IEEE Region 10 International Conference on EC3-Energy, computer, Communication and Control Systems, TENCON 1991

作者： Ilyas, Mohammad Rao, Suhas P. Chandra, Vinod Department of Computer Science and Engineering Florida Atlantic University Boca Raton FL33431 United States AT and T Bell Laboratories Cravvfords Corner Road HolmdelNJ07733 United States Department of Electrical Engineering Indian Institute of Technology New Delhi110016 India

ISBN: (纸本)0780305388

With a rapidly growing trend of using fiber-optics as transmission media, there is an immense interest in high speed local area networks (LAN s). These networks offer an efficient and cost-effective means of communication within a relatively small geographical area. Bus and ring topologies are the two most popular topologies for fiber optics LANs. In this paper, however, we will only consider bus topology. In a typical fiber optics bus network, transmission is unidirectional. In our study the time is slotted and each station attempts to transmit in an empty slot persistently with a preassigned probability. Messages are assumed to be of variable length and are segmented into fixed size packets such that each packet fits in a slot. Fair access to the shared transmission medium can be achieved if access probabilities are assigned propetly to all stations. Three probability assignment schemes are considered: uniform, linearly increasing, exponentially increasing, and optimaI. The average delay per message for this network is studied through a simulation program for various probability assignment techniques. This study shows that there is significant difference in performance of these techniques. © 1991 IEEE.

关键词： Fiber optics

来源：评论

学校读者我要写书评

暂无评论

Improving the performance of CELP-based speech coding at low bit rates

Improving the performance of CELP-based speech coding at low...

引用

IEEE International Symposium on Circuits and Systems (ISCAS)

作者： T. Taniguchi F. Amano M. Johnson Radio Communication Processing Technology Section Fujitsu Laboratories Limited Kawasaki Japan Department of Electrical Engineering and Computer Science MIT Cambridge MA USA

The authors review the CELP (code excited linear prediction) coding algorithm, and the efforts recently made for improving the performance and reducing the complexity. The efforts for improving the coding performance have been aimed not only at making the quality better, but also at further reducing the bit rate without degrading the quality. A sparse-delta codebook is introduced as an example of a codebook with a computationally efficient structure. Multimode coding is then described for improving the perceptual quality of CELP at low bit rates.< >

关键词： Speech coding Bit rate Speech synthesis Speech processing Vector quantization Speech analysis Computational complexity Search methods Degradation Signal synthesis

来源：评论

学校读者我要写书评

暂无评论

Parallel strategies for geometric probing

Parallel strategies for geometric probing

引用

IEEE International Conference on Robotics and Automation (ICRA)

作者： M. Lindenbaum A. Bruckstein NTT Basic Research Laboratories Japan Department of Electrical Engineering Technion-Israel Institute of Technology Haifa Israel Department of Computer Science Technion-Israel Institute of Technology Haifa Israel

The problem of recovering the shape of planar objects from line or finger probings arises in robotics. This problem is addressed under the assumption that composite probings are made. One composite probing comprises several (k) line or finger probings done simultaneously. An investigation is conducted of planar polygon reconstruction from sequences of composite k-probings. For every value of k, a lower bound on the number of k-probings required for reconstruction under any strategy is obtained. Specific strategies which are provably almost optimal are provided.< >

关键词： Probes Fingers Robot sensing systems computer science Shape Ice Solid modeling Position measurement

来源：评论

学校读者我要写书评

暂无评论

Comparative Simulation of a Threshold-Based Congestion Avoidance in Broadband ISDNs

Comparative Simulation of a Threshold-Based Congestion Avoid...

引用

IEEE Region 10 International Conference TENCON

作者： M. Ilyas S.P. Rao V. Chandra Department of Computer Science and Engineering Florida Atlantic University Boca Raton FL USA AT and T Bell Laboratories Inc. Holmdel NJ USA Department of Electrical Engineering Indian Institute of Technology New Delhi India

关键词： B-ISDN ISDN Asynchronous transfer mode Bandwidth Computational modeling Bit rate Resource management Optical fibers computer science computer simulation

来源：评论

学校读者我要写书评

暂无评论

MEMCAD capacitance calculations for mechanically deformed square diaphragm and beam microstructures

MEMCAD capacitance calculations for mechanically deformed sq...

引用

International Conference on Solid State Sensors and Actuators (TRANSDUCERS)

作者： B.P. Johnson S. Kim S.D. Senturia J. White Microsystems Technology Laboratory and the Research Laboratory of Electronics Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA Dept. of Electr. Eng. & Comput. Sci. MIT Cambridge MA USA

A Micro-ElectroMechanical computer-Aided Design (MEMCAD) system is being developed to make it possible for microsensor designers to perform realistic simulations easily and quickly. Carefully selected commercial software packages have been linked with specialized databases and numerical programs to allow a designer to enter a three-dimensional microsensor geometry and quickly perform both mechanical and electrical analysis. The authors briefly describe the system and demonstrate its effectiveness by accurately calculating the capacitance versus pressure (or force) curve for a square diaphragm deformed by a differential pressure and for a rectangular beam deflected by a centrally applied force. The MEMCAD system has successfully implemented the following: querying a material property database for material property insertion, combining a 3-D solid model with displacement information from the finite element method, and interfacing the 3-D solid model format with a capacitance extraction program.< >

关键词： Capacitance Microsensors Material properties Solid modeling Design automation Computational modeling computer simulation Software packages Spatial databases Geometry

来源：评论

学校读者我要写书评

暂无评论

A PROGRAMMABLE DEMODULATOR FOR OVERSAMPLED ANALOG-TO-DIGITAL MODULATORS

引用

IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS 1990年第9期37卷 1092-1103页

作者： SHERSTINSKY, A SODINI, CG Microsystems Technology Laboratory Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA

A programmable DSP (digital signal processor) architecture for use in an oversampled A/D (analog-to-digital) converter system is introduced. Based on this architecture, a set of synchronization equations for configuring the entire oversampled system for arbitrary speed-accuracy specifications is presented. The generality and simplicity of the architecture allow the reduction of this procedure to running high-level, user-friendly software and programming PROMs (programmable read-only memories). The architecture was implemented in a 2.0- mu m N-well CMOS technology. Fabricated samples demonstrated the ability to handle many applications, including 16 b of SNR (signal-to-noise ratio) for the digital audio (20-kHz baseband) and 18 b of SNR for voiceband (4-kHz baseband). It is concluded that this DSP architecture is the most general and efficient computation engine for FIR/IIR (finite impulse response/infinite impulse response) filtering of 1-b signals. It is capable of over 30 MIPs. The architecture\'s simplicity and flexibility facilitate its interfacing with a high-level, user-friendly software package.

关键词： ARCHITECTURE Building construction Software packages Processor Architectures PROGRAMMABLE Baseband

来源：评论

学校读者我要写书评

暂无评论

A STUDY OF 3 MICROFABRICATED VARIABLE-CAPACITANCE MOTORS

引用

SENSORS AND ACTUATORS A-PHYSICAL 1990年第1-3期21卷 173-179页

作者： MEHREGANY, M BART, SF TAVROW, LS LANG, JH SENTURIA, SD SCHLECHT, MF Microsystems Technology Laboratories Laboratory for Eletromagnetic and Electronic Systems Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA 02139 U.S.A.

This paper discusses the design, microfabrication, operating principles and experimental testing of three types of rotary variable-capacitance micromotors. The advantages and disadvantages of these motors are discussed. The three motor types are top-drive, side-drive and harmonic side-drive. In this work, the micromotors are surface micromachined using heavily-phosphorus-doped polysilicon for the structural material, deposited oxide for the sacrificial layers and LPCVD nitride for electrical isolation. Frictional forces associated with electric pull-down forces on the rotor are dominant in the side-drive and harmonic side-drive motors fabricated and tested to date. Air drive and electric excitation have been used in studying these effects. Side-drive micromotors have been successfully operated by a three-phase electrical signal with the rotors air-levitated. With air levitation, successful operation is achieved at bipolar excitations greater than 80 V across 4 μm air-gap motors having eight rotor and twelve stator poles, with only half of the stator poles excited. Motor operation is sustained indefinitely.

关键词： Electric Motors

来源：评论

学校读者我要写书评

暂无评论

A LOCOS PROCESS FOR AN ELECTROSTATIC MICROFABRICATED MOTOR

引用

SENSORS AND ACTUATORS A-PHYSICAL 1990年第1-3期23卷 893-898页

作者： TAVROW, LS BART, SF LANG, JH SCHLECHT, MF Microsystems Technology Laboratories Laboratory for Electromagnetic and Electronic Systems Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA 02139 U.S.A.

A novel process based on local oxidation of silicon (LOCOS) for fabricating planar electric micron-scale radial-gap motors is described. Issues relating to the design, fabrication and performance of these micromotors are discussed, with particular emphasis given to the LOCOS process. Functioning variable-capacitance motors with rotors of 50 μm radii are described in detail and qualitative results of their operation with air levitation are presented. Finally, the integration of electronics with the micromotors on the same substrate is discussed. We have discussed the main issues involved in designing and fabricating electric variable-capacitance motors. Radial-gap motors have been selected for controllable instability and ease of fabrication. Furthermore, by examining the fabrication requirements of high-precision thick structures, we conclude that planarization is required unless greatly increased process complexity can be tolerated. The LOCOS-based process has thus been developed because it is inherently planar, unlike standard surface micromachining processes. Micron-scale motors and other structures have been successfully fabricated using the new LOCOS-based process. These motors were spun electrostatically up to speeds over 10 00O rpm, without visible signs of wear, when levitated by an externally generated air bearing. We are investigating the use of reduced-friction coatings such as Si 3 N 4 [2] or Teflon [19] in the bearing structure to eliminate the need for external air levitation. The inherent planarization of the motor not only facilitates the fabrication but may also facilitate the development of certain applications that require some form of direct cover or package. Starting and load transients must be sensed and controlled for stable VC motor performance. Closed-loop control, however, is virtually impossible witho

关键词： Electric Motors

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：