Custom Integrated Circuits

Contains reports on twelve research projects.Analog Devices, Inc.International Business Machines, Inc.Joint Services Electronics Program (Contract DAAL03-86-K-0002)Joint Services Electronics Program (Contract DAAL03-89-C-0001)U.S. Air Force - Office of Scientific Research (Grant AFOSR 86-0164)Rockwell International CorporationOKI Semiconductor, Inc.U.S. Navy - Office of Naval Research (Contract N00014-81-K-0742)Charles Stark Draper LaboratoryNational Science Foundation (Grant MIP 84-07285)National Science Foundation (Grant MIP 87-14969)Battelle LaboratoriesNational Science Foundation (Grant MIP 88-14612)DuPont CorporationDefense Advanced Research Projects Agency/U.S. Navy - Office of Naval Research (Contract N00014-87-K-0825)American Telephone and TelegraphDigital Equipment CorporationNational Science Foundation (Grant MIP-88-58764

On the invertibility of finite state machines

Structural properties of finite state machines invertible with delay

Testing in context: Efficiency and executability

Testing each software component in isolation is not always feasible. We consider testing a deterministic Implementation Under Test (IUT) together with some other correctly implemented components as its context. One of the essential issues of testing in context is test executability problem, i.e., tests generated solely from the specification of the IUT may not be executable due to the uncontrollable interaction between the IUT and its context. On the other hand, generating a test sequence from the abstract specifications of a stateful IUT and its context often suffers from the well-known state explosion problem. In this dissertation, we solve the problem of generating a minimal-length test sequence from a given specification of a stateful IUT and its embedded context. By adopting model checking techniques, we avoid the state explosion problem during test generation and avoid the test executability problem during testing in context

A general purpose State Architecture Simulator for discrete systems with application in data communication protocols

The increasing practical importance of data communications and computer networking has generated a noticeable amount of research on formal methods to support the design, specification, validation, simulation, and implementation of data communication protocol systems;This dissertation presents a language, namely State Architecture Notation (SAN), for specifying models of protocol systems and describes an important companion simulation tool, namely, the State Architecture Simulator (SAS);The syntax and the semantics of SAN are presented. Protocol systems are modelled by specifying an interconnection of the nine basic components defined in SAN: finite-state machine (FSM), pulsed combinational function (CFP), static combinational function (CFS), pulsed delay (DELP), static delay (DELS), queue (QUE), derivative (DER), clock (CLK), and environment (ENV);The design and the implementation of SAS are described. SAS contains two PASCAL programs and a VAX command language procedure that compiles, executes, and reports on simulations of user supplied SAN specifications of protocol systems. SAS is an interactive event driven system allowing users to examine the system status, to assign inputs, and to save system status at a terminal;The operational steps involved in creating and running a SAS executable simulated system from the SAN model are described. Several simulation models, including the start-stop protocol and a sub-system of the ADCCP protocol, were run. The simulation experience demonstrates that the SAN and the SAS are useful tools in protocol design;The evaluation of SAN and SAS is presented along with some suggestions of ways that SAN and SAS can be improved

Knowledge Based Systems: A Critical Survey of Major Concepts, Issues, and Techniques

This Working Paper Series entry presents a detailed survey of knowledge based systems. After being in a relatively dormant state for many years, only recently is Artificial Intelligence (AI) - that branch of computer science that attempts to have machines emulate intelligent behavior - accomplishing practical results. Most of these results can be attributed to the design and use of Knowledge-Based Systems, KBSs (or ecpert systems) - problem solving computer programs that can reach a level of performance comparable to that of a human expert in some specialized problem domain. These systems can act as a consultant for various requirements like medical diagnosis, military threat analysis, project risk assessment, etc. These systems possess knowledge to enable them to make intelligent desisions. They are, however, not meant to replace the human specialists in any particular domain. A critical survey of recent work in interactive KBSs is reported. A case study (MYCIN) of a KBS, a list of existing KBSs, and an introduction to the Japanese Fifth Generation Computer Project are provided as appendices. Finally, an extensive set of KBS-related references is provided at the end of the report