Showing papers on "Design tool published in 1984"

A High Level Synthesis Tool for MOS Chip Design

Abstract: This paper describes a design tool called Functional Design System (FDS) that supports high level MOS LSI design. Designers can build circuits at the register transfer level by using a set of high level FDS primitives. FDS then automatically produces in seconds an accurate and efficient polycell implementation for these primitives. Therefore, the design cycle time can be reduced significantly. FDS is an integral part of a larger CAD system [1] which supports other aspects of the design cycle, namely, graphical design capture, simulation, test generation, and layout. The system has proved to be highly successful in helping designers to develop extremely reliable chips in a short time frame.

A one-dimensional disk model simulation for klystron design

Abstract: In 1982, one of the authors (Okazaki), of Toshiba Corporation, wrote a one-dimensional, rigid-disk model computer program to serve as a reliable design tool for the 150 MW klystron development project. This is an introductory note for the users of this program. While reviewing the so-called disk programs presently available, hypotheses such as gridded interaction gaps, a linear relation between phase and position, and so on, were found. These hypotheses bring serious limitations and uncertainties into the computational results. JPNDISK was developed to eliminate these defects, to follow the equations of motion as rigorously as possible, and to obtain self-consistent solutions for the gap voltages and the electron motion. Although some inaccuracy may be present in the relativistic region, JPNDISK, in its present form, seems a most suitable tool for klystron design; it is both easy and inexpensive to use.

Application of computational aerodynamics to airplane design

Abstract: OMPUTATIONAL aerodynamics has been defined as the engineering discipline which deals with the simulation of flowfields about aircraft through the numerical solution of the equations of fluid motion using digital computers This simulation process is referred to as numerical flow simulation; another way of simulating flow about airplanes is the wind tunnel Wind tunnel technology is almost as old as aeronautics; wind tunnel testing became the principal tool of aerodynamic design and development very early in the history of airplane engineering Of course in addition to the ex perimental approach analytical methods based on aerodynamic theory always have been used to obtain valuable design information; but in order to reduce the computational effort to a humanly tolerable level, many simplifying assumptions had to be introduced These simplifications not only had to do with the mathematical modeling of the physical problem e g inviscid incompressible flow but they also involved the geometry of the configuration and flow condition e g the lifting line concept to represent a wing These simplications did not make possible the calculation of many aerodynamic characteristics and posed a high degree of uncertainty about the accuracy and validity of the numerical results Therefore these results could be used only as design guidelines and large emphasis had to be placed on wind tunnel testing The advent of the digital computer and the impressive growth of its capabilities and cost effectiveness—as illustrated in Fig 1—now have made it possible to eliminate many of the simplifications that had been introduced in analytical methods This has increased the amount of in formation that can be extracted from a calculation and at the same time provides more accuracy and a greater range of validity for the results of numerical flow simulation This has turned computational aerodynamics into a major tool for airplane design This paper surveys the use of computational aerodynamics as a design tool Much development work in computational aerodynamics is of a fundamentally scientific nature con cerned with what type of numerical flow simulation is feasible within the boundaries of our knowledge of flow physics and numerical algorithms This paper deals with the engineering aspects of numerical flow simulation i e. what elements are practical in an environment where schedule and budget constraints predominate and where multidisciplinary in teraction is the way of life and particularly with the factors that affect its effectiveness in such an environment Even though computer system characteristics do fundamentally affect the effectiveness of computational aerodynamics they are not the subject of this paper The survey presented here is of necessity, selective and consequently incomplete The main intent of this paper is to highlight those elements of computational aerodynamics that are important for airplane application what form they have taken and to indicate what future developments are considered necessary to increase the general utility of computational aerodynamics Three dimensionality geometrical complexity and computational efficiency are stressed as overdriving considerations for design application First some general characteristics and needs of airplane design projects are discussed; within this context particular attention is given to the meaning of effectiveness and the identification of the computer code characteristics that affect it Next the code elements that are part of a typical numerical flow simulation are identified; the nature of these elements how they impact code effectiveness and how they are affected by considerations of effectiveness are addressed subsequently The author has drawn freely from developments at the Lockheed California Company to illustrate some points; for this he is indebted to many of his colleagues at Lockheed

A finite element computer program for the analysis of masonry arches

Abstract: The report describes the first stage in the development of a non-linear finite element program for the analysis of masonry (and other) arch bridges. The main elements of this first stage involve the finite element theory and the structure of the computer program in addition to the data input requirements. A brief review of other related work is also included as are some provisional computer applications. For the present, the computer program must be considered as a research rather than a design tool but it is intended that a second stage of development and testing will lead to a more user-orientated computer program. (Author/TRRL)

Systematic Design of Automation, Protection, and Control in Substations

Abstract: A design tool is proposed for the subsequent development steps of a substation control system, viz. task specification, system design, software production, and hardware implementation. Process control is characterized by properties like causality, determinism, asynchronity, stochastic events, and real-time control. All control tasks can directly be expressed in terms of a subclass of Petri nets with the above mentioned properties. The formal Petri net properties guarantee well defined interfaces (supporting task sharing), limit consequences of changes (in technology or by extension) to local alterations (i.e. reusability of the unaffected parts), permit concurrent task formulation (supporting availability and response time respectively) and facilitate formal error elimination. Moreover, the system design can be mapped via software to hardware by formal procedures.

Emulation as a design tool in the development of real-time control systems

Abstract: A major facility for manufacturing research is being established at the National Bureau of Standards. The Automated Manufacturing Research Facility (AMRF) will provide testbed where measurement research of computer integrated manufacturing systems can be performed. The control architecture of the facility is based on a sensory-interactive, modular, hierarchical, feedback system. Each module is represented as a finite state machine that interacts through a shared time-sliced common-memory where command, feedback and database information is stored.A hierarchical control system emulator (HCSE) has been developed that allows the system to be designed and tested before implementation on the actual hardware. The HCSE has been successfully used in the AMRF project as a design management tool, providing a complete specification of the control software. It is also used as a testing aid that allows a given module (i.e., a robot control system) to interact with emulated control modules substituting for unavailable AMRF hardware.

Icon: A Tool for Design at Schematic, Virtual Grid, and Layout Levels

Abstract: The design of a custom VLSI chip requires work at several levels of abstraction. For example, random logic is naturally described as schematics, hand-entered layouts are naturally entered on a virtual grid, and machine-generated or compacted layouts are edited on an accurate, geometrically fixed grid. Icon is a new computer-aided design tool that allows these aspects of design to be handled simultaneously. It provides a schematics entry and simulation system, a virtual-grid compacter, and a layout editor. The user interface is consistent across these functions, and it is possible to mix them on the screen. In particular, Icon allows the user to insert pieces of layout, such as PLAs, directly into a schematic. This eliminates the effort of developing a logic diagram for them and provides accurate simulation with both interactive graphics and program level capabilities. Several dozen full-custom NMOS and CMOS chips have been designed with Icon, including a number of local area network support chips, a high-speed RAM, and high bandwidth data switches.

Component based performance simulation of HVAC systems

Abstract: The design process of HVAC (Heating, Ventilation and Air Conditioning) systems is based upon selecting suitable components and matching their performance at an arbitrary design point, usually determined by an analysis of the peak environmental loads on a building. The part load operation of systems and plant is rarely investigated due to the complexity of the analysis and the pressure of limited design time. System simulation techniques have been developed to analyse the performance of specific commonly used systems: however these 'fixed menu, simulations do not permit appraisal of hybrid and innovative design proposals. The thesis describes research into the development of a component based simulation technique in which any system may be represented by a network of components and their interconnecting variables. The generalised network formulation described is based upon the engineer's schematic diagram and gives the designer the same flexibility in simulation as is available in design. The formulation of suitable component algorithms using readily available performance data is discussed, the models developed being of a 'lumped parameter' steady state form. The system component equations are solved simultaneously for a particular operating point using a gradient based non-linear optimisation algorithm. The application of several optimisation algorithms to the solution of RVAC systems is described and the limitations of these methods are discussed. Conclusions are drawn and recommendations are made for the required attributes of an optimisation algorithm to suit the particular characteristics of HVAC systems. The structure of the simulation program developed is given and the application of the component based simulation procedure to several systems is described. The potential for the use of the simulation technique as a design tool is discussed and recommendations for further work are made.

Hybrid computer simulation and validation of a closed cycle diesel engine

Abstract: The paper describes, in outline, the development and execution of a hybrid computer simulation of a closed cycle diesel engine power system. The simulation was developed interactively with an experimental test rig, and a comparison of results is discussed arising from the validation exercise. The ultimate application of the technology is directed towards the offshore industries, where availability of a more power intensive alternative to the lead and battery is sought, as the requirement for autonomous deep water power sources becomes more pressing. Due to the highly interactive nature of the various sub systems identified in such a closed cycle concept, it was decided to implement simulation techniques to provide an intuitive insight into physical phenomena, whilst simultaneously providing an analytical tool for objective assessment of various proposed control strategies. Starting from an essentially elementary model, the simulation was developed to a stage where excellent correlation with observed test rig behaviour was observed. The model thereby constitutes a validated design tool, capable of performing extrapolative studies of high reliability, for application with future proposed full scale developments.

Microcomputer-aided microprogrammed control unit design

Abstract: A CAD technique for microprogrammed controllers with multiway branching, based on read-only memories, registers and multiplexers, has been worked out that is suitable for microcomputers and yields nearly optimum solution in reasonable time. A design strategy, that can be expressed as a number of selection rules of different priority, has been implemented simly by allocating a certain number of points to each element under selection with respect to each design criterion. This makes possible fast comparison of different alternatives. Controllers with up to 50 states and 16 input variables can be designed on microcomputers with the extended BASIC and only 16 kB of RAM in 10° - 101 minutes. The size of solvable problems increases with the available RAM, though. The technique is a useful design tool for medium speed controllers.

Top-down design within a functional environment†

Abstract: This paper describes a design tool for use within the INTERLISP1 environment. The design tool, DT, is based upon the design methodology described by the general term, top-down design and is novel in that it attempts to apply this design method to a functional programming environment. Also novel is the method whereby the generation of the design can occur in parallel with the implementation of the design. This allows a design process more in accord with the needs of functional programmers.

A Micro-Computer Aided Design Tool: Casamo

Abstract: CASAMO is a micro-computer aided design tool, specific for architects and designers which allows easy optimization of solar energy use in housing: energy saving and comfort.

Towards a design tool for ship manoeuvrability

Abstract: This paper briefly reviews the existing maneuvering theories and the methods employed to obtain the hydrodynamic coefficients used in these theories. A simplified model developed and used at Lloyd's Register illustrates simulations of deep water maneuvers of the tanker Esso Osaka.

ACOSS SEVENTEEN (Active Control of Space Structures)

Abstract: : This is the Control Dynamics Company final technical report on extended analysis and evaluation of the Control Techniques of Large Space Structures. The research effort was primarily aimed at mathematical model development and control systems analysis and design tool development. Additional keywords; Spacecraft, Structural mechanics, Experimental design, Control theory, Stability, Damping, Cost analysis, Line of sight, Computations, Flow charting, Computer aided design.

A database approach to computer-aided design of integrated circuits using structured tiling

Abstract: The use of database systems for engineering design has been the subject of a considerable amount of research in the past. However, much of this work has been concerned with the efficient description of integrated circuit layout details. This dissertation describes a database approach to the development of a system for the hierarchical design of integrated circuits in a cell-based environment. Because the system is specifically tailored for a cell-based design methodology, the emphasis has been shifted from the representation of circuit layout details to the maintenance of the cell library. A number of factors indicate the need of a database system approach. The explosion in computer-aided design tool development brought about by the introduction of VLSI design to the Computer Science community has created a situation where a multitude of programs exist without a uniform way of representing all of the required design characteristics. As a result, large amounts of effort are required to create interfaces between tools. If integrated circuit complexities continue to increase at an exponential rate, data storage requirements will increase markedly. In addition, the common practice of representing a circuit at multiple levels of abstraction (system, block, gate, schematic, and layout level) further complicates the problem. The use of large VLSI design groups where the work is partitioned among a number of designers introduces data management problems not present when a small group is responsible for the design. This is due to the many semiprivate databases created when individuals check portions of a design out of a public database for modification. Another reason for using a database system approach in this work is to support Structured Tiling. This methodology uses primitive tiles (cells) placed on regular grids to implement integrated circuits. Multiple sets of tiles, each specially tailored to the implementation of a particular type of module are contained in the system. In contrast to more conventional design systems, the emphasis here is on the maintenance of the library of tile sets and support for design through the placement of tiles. The design system developed in this work treats the complete integrated circuit design process. This entails tile definition, layout, and simulation as well as the creation of circuit blocks from collections of the tiles. Finally, hierarchical placement, interconnection, and simulation of the resulting circuit blocks is supported.

Automated synthesis of control systems: a design approach

Abstract: A new, interactive, computer-aided design tool has been developed for the synthesis of flight control systems and is discussed in this paper. Open and closed-loop frequency response requirements are imposed, simultaneously, for linear multivariable systems with varying plant dynamics for a user-defined control system configuration. The user-defined control parameters (compensation variables) consist of gains, filter coefficients and time constants. An objective function is developed, which is a function of violations in system stability and performance requirements, and is based upon the same classical objectives and constraints that the control system analyst considers when developing control laws. Optimum nonlinear programming algorithms are employed in the search for local constrained solutions in which violations either vanish or are minimized for a proper selection of control variables. System stability is not a precondition nor are minimum phase systems. A longitudinal flight control system for a typical high performance tactical fighter aircraft is synthesized, and it is shown that vastly increased productivity results by using this design tool when compared with more conventional design methods. The use of this automated approach is clearly established as superior and cost effective, and is offered as a significant improvement in feedback control system synthesis.

The design of optimal relational data model

Abstract: A method for generating an optimal relational data model is presented in this paper. This method is semi-automatic, and it is an improvement over previous methods suggested by Codd, Bernstein, Fagin and others. It removes some of the problems found in the previous techniques. It increases the amount of automation, and it relaxes some of the input requirements. Thus, it provides a design tool which is easier to use then previous tools, and which results in an optimal set of normalized relations.

A Computer-Based System for Workstation Design and Analysis

Abstract: The Crew Systems Development Branch of the US Air Force Wright Aeronautical Laboratories is pursuing a system of computer-aided design and evaluation techniques (CADETs) for aircraft crew station development. Composed of individual computer-based human factors design tools and analysis methods, the system's key element is a user-interface module (UIM). The UIM serves as the single user-computer interface, through which all CADETs are accessed, eliminating many of the potential disadvantages normally associated with such an approach (e.g. diverse user backgrounds and varying user familiarity with computers). The CADETs are being implemented in a modular architecture to permit easy upgrade, replacement, or addition of any design tool or analysis technique. These features, and others discussed herein, are being combined to produce a system with numerous desirable attributes including user friendliness and software portability. A powerful, effective CADET system will result, employing computer graphic, analyt...

A simulation of diesel injection system using a hybrid computer

Abstract: The importance of diesel injection system simulation as a design tool is widely recognized and various models have been developed. But most of the simulations are implemented with digital computers. A new simulation model using digital-analog hybrid computer has been developed. The objective of this simulation is to optimize the injection system design with minimum time by interactive method. The hybrid computer meets this requirement. One of the main features of this model is the introduction of a simple equation about the bulk modulus of elasticity of fuel oil. It is expressed as a function of the oil pressure and the volume ratio of bubble to fluid. This paper describes the detail of the modeling and the programming of this simulation for hybrid computer, comparison between calculation and experiments and some examples of application to the actual diesel injection system.