A Festschrift in honor of Professor Marvin L. Cohen This volume is a Festschrift in honor of Professor Marvin L. Cohen. The articles, contributed by leading researchers in condensed matter physics, high-light recent advances in the use of quantum theory to explain and predict properties of real materials. The invention of quantum mechanics in the 1920's provided detailed descriptions of the electronic structure of atoms. However, a similar understanding of solids has been achieved only in the past 30 years, owing to the complex electron-ion and electron- electron interactions in these...

Supercomputers are the largest and fastest computers available at any point in time. The term was used for the first time in the New York World, March 1920, to describe "new statistical machines with the mental power of 100 skilled mathematicians in solving even highly complex algebraic problems. " Invented by Mendenhall and Warren, these machines were used at Columbia University'S Statistical Bureau. Recently, supercomputers have been used primarily to solve large-scale prob lems in science and engineering. Solutions of systems of partial differential equa tions, such as those found in...

Dynamic modelling is the fundamental building block for mechanism analysis, design, control and performance evaluation. One class of mechanism, legged machines, have multiple closed-chains established through intermittent ground contacts. Further, walking on natural terrain introduces nonlinear system compliance in the forms of foot sinkage and slippage. Closed-chains constrain the possible motions of a mechanism while compliances affect the redistrubution of forces throughout the system.

7. 2 Element Stiffness Matrix of a Space Truss Local Coordinates 221 7. 3 Transformation of the Element Stiffness Matrix 223 7. 4 Element Axial Force 224 7. 5 Assemblage ofthe System Stiffness Matrix 225 7. 6 Problems 236 8 STATIC CONDENSATION AND SUBSTRUCTURING 8. 1 Introduction 239 8. 2 Static Condensation 239 8. 3 Substructuring 244 8. 4 Problems 259 9 INTRODUCTION TO FINITE ELEMENT MEmOD 9. 1 Introduction 261 9. 2 Plane Elasticity Problems 262 9. 3 Plate Bending 285 9. 4 Rectangular Finite Element for Plate Bending 285 9. 5 Problems 298 APPENDIX I Equivalent Nodal Forces 301 APPENDIXll...

The physical processes which initiate and maintain motion have been a major concern of serious investigation throughout the evolution of scientific thought. As early as the fifth century B. C. questions regarding motion were presented as touchstones for the most fundamental concepts about existence. Such wide ranging philosophical issues are beyond the scope of this book, however, consider the paradox of the flying arrow attri buted to Zeno of Elea: An arrow is shot from point A to point B requiring a sequence of time instants to traverse the distance. Now, for any time instant, T, of the...

This book introduces a theory, Naive Semantics (NS), a theory of the knowledge underlying natural language understanding. The basic assumption of NS is that knowing what a word means is not very different from knowing anything else, so that there is no difference in form of cognitive representation between lexical semantics and ency clopedic knowledge. NS represents word meanings as commonsense knowledge, and builds no special representation language (other than elements of first-order logic). The idea of teaching computers common sense knowledge originated with McCarthy and Hayes (1969), and...

Log-domain and translinear filters provide a competitive alternative to the challenges of ever increasing low-voltage, low-power and high frequency demands in the area of continuous-time filters. Since translinear filters are fundamentally large-signal linear, they are capable of realizing a large dynamic range in combination with excellent tunability characteristics. Large-signal linearity is achieved by exploiting the accurate exponential behavior of the bipolar transistor or the subthreshold MOS transistor. A generalization of the dynamic translinear principle exploiting the square law...

Arobotmustperceivethethree-dimensionalworldifitistobeeffective there. Yet recovering 3-D information from projected images is difficult, and still remains thesubjectofbasic research. Alternatively, onecan use sensorsthatcanprovidethree-dimensionalrangeinformationdirectly. The technique ofprojecting light-stripesstartedto be used in industrialobject recognition systems asearly asthe 1970s, andtime-of-flight laser-scanning range finders became available for outdoor mobile robotnavigation in the mid-eighties. Once range data are obtained, a vision system must still describe the scene in terms of...

Digital image business applications are expanding rapidly, driven by recent advances in the technology and breakthroughs in the price and performance of hardware and firmware. This ever increasing need for the storage and transmission of images has in turn driven the technology of image compression: image data rate reduction to save storage space and reduce transmission rate requirements. Digital image compression offers a solution to a variety of imaging applications that require a vast amount of data to represent the images, such as document imaging management systems, facsimile...

One of the ultimate goals in Robotics is to create autonomous robots. Such robots will accept high-level descriptions of tasks and will execute them without further human intervention. The input descriptions will specify what the user wants done rather than how to do it. The robots will be any kind of versatile mechanical device equipped with actuators and sensors under the control of a computing system. Making progress toward autonomous robots is of major practical inter est in a wide variety of application domains including manufacturing, construction, waste management, space exploration,...