CAD System For Design Research Articles

A submicrometer CMOS embedded SRAM compiler

A highly flexible memory generation system that produces high-density synchronous single- or dual-port static memories has been developed using a 0.7- mu m L/sub eff/ CMOS technology. The fully diffused memories are embedded into a gate-array environment. Configurations upwards of 1K words*256 b and 16K words*16 b have been obtained. Single-port address access times are, for example, 6.2 ns for 8K and 6.9 ns for 32K SRAMs. The Memorist SRAM Compiler provides for accurate timing characterization and is tightly integrated into an ASIC design CAD system. A gate-array-based test-chip cluster consisting of four 7.3*7.3 mm dies with 16 embedded diffused memories has also been developed. >

Schematic-designer: a knowledge-based CAD system for schematic design in architecture

Considering the nature of design problems and problem-solving behaviour, three major problem areas of computer-aided architectural design are the ill-defined nature of design problems, knowledge representation and manipulation, and knowledge acquisition. This study follows a model-based approach to address and analyse the problems. A conceptual model of schematic design is developed taking into consideration geometry, topology, and orientation of spaces. This model is translated into predicate logic and represented in PROLOG. A knowledge-based system named Schematic-Designer is developed to test the representation scheme. Knowledge acquisition of Schematic-Designer follows a process of architectural programming to acquire the domain knowledge. The system is demonstrated using as an example a single-family house to generate schematic diagrams. The demonstration shows that the system is able to generate designs which satisfy the design goals.

A knowledge-based CAD system for concurrent product design in injection moulding

Abstract The synthesis of supplementary features of injection-moulded parts has been done empirically, since it requires profound knowledge about the features mouldability and causal effects on the properties of the part, which are not available to designers through the current CAD systems. RIBBER is a knowledge module which contains knowledge to permit nonexperts as well as mould design experts to generate acceptable supplementary features of injection-moulded pans. A knowledge-based CAD system is constructed by adding the knowledge module, RIBBER, for mould feature synthesis and appropriate CAE programs for mould design analysis to an existing geometric modeller in order to provide designers, at the initial design stage, with comprehensive process knowledge for feature synthesis, performance analysis and feature-based geometric modelling. A knowledge-based CAD system is a new tool which enables the concurrent design and CIM, with integrated and balanced design decisions, at the initial design stage of i...

Knowledge-based CAD system for protective packaging design

Protective packaging buffer design is a complex process which involves manipulating both analytical and graphical data, and expert knowledge. The design activities of this process can be represented as a series of procedural tasks, and it is therefore suitable for design automation efforts. Currently, the design activities of the protective packaging buffers are predominantly manual and done on a trial and error basis. In this paper, PROPACK, a knowledge-based CAD system which has been developed to automate this design process will be discussed. A description of how the knowledge and information in PROPACK are structured and stored in the database will also be made. Preliminary tests have found that PROPACK is able to generate possible design solutions that either require external or simple internal cushioning features used for protection. These results have found to compare quite favourably with the BASF worked examples.

An integrated CAD system for algorithm-specific IC design

LAGER is an integrated computer-aided design system for algorithm-specific integrated circuit design, targeted at applications such as speech processing, image processing, telecommunications, and robot control. LAGER provides user interfaces at behavioral, structural, and physical levels and allows easy integration of novel CAD tools. LAGER consists of a behavioral mapper and a silicon assembler. The behavioral mapper maps the behavior onto a parameterized structure to produce microcode and parameter values. The silicon assembler then translates the filled-out structural description into a physical layout, and, with the aid of simulation tools, the user can fine tune the data path by iterating this process. The silicon assembler can also be used without the behavioral mapper for high-sample-rate applications. A number of algorithm-specific ICs designed with LAGER have been fabricated and tested, and as examples, a robot arm controller chip and a real-time image segmentation chip are described.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Object programming for CAD

The use of object-oriented programming to simplify the design and implementation of CAD systems is discussed. The three features common to all languages that support object-oriented programming data abstraction, inheritance, and runtime-function determination are examined. Examples are given to illustrate the advantages of object-oriented methods. How to build an embryonic CAD framework and when to use an object-oriented language are addressed. Object-oriented databases are defined. >

Thermal Analysis in CAD of Hybrid Circuits

In this contribution a short review is given on thermal analysis of hybrid circuits using 2‐D, 3‐D and time‐dependent models. It will be shown which models are necessary to be included in a CAD system for hybrid circuit design.

Technology CAD for competitive products

Recent trends in the integration of process-, device-, and circuit-modeling tools and the current rapid emergence of Unix-based computing environments of networked workstations and computer engines makes possible user-friendly, task-based CAD systems for technology optimization, characterization, and cell design. The authors discuss these trends and identify opportunities to use technology CAD tools in the development of competitive technologies and products. It is shown that the ability to provide design centering and extreme-case analysis related to process variables has been a key to aggressive design of robust IC products. This capability results from efforts in the early to mid-1980's to establish integrated modeling systems such as MECCA, the application of general-purpose optimization capabilities such as WATOPT and CENTER, and recent advances in open and powerful computing environments (principally Unix-based distributed resources).< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A Computer Aided Design System for Three-Dimensional Compression Mold Heating

Compression mold processing of composites involves taking the charge through a material dependent temperature and pressure path, inducing thermochemical reactions to cure the charge. While curing, specific uniform temperatures are required for a time, and spatial variation of the cavity surface temperature can lengthen time needed to cure and also cause voids and residual stresses, reducing the quality of the finished part. Towards mold heating design goal of uniform cavity surface temperature, an interactive CAD system for compression mold heating design has been developed. The system accepts a previously defined three dimensional, discretized goemetry and uses a Boundary Element Method (BEM) analysis which includes the effects of long, thin electric resistor heating rods, and is coupled with the CONMIN algorithm for constrained minimization of an objective error function to obtain uniform temperature over the cavity surface. Realistic constraints are featured to insure design feasibility. The problem is organized with design in mind to allow fast, easy redesign and a sensitivity study along with the optimization. The approach used is unique and is the first application of this type of optimization to three dimensional mold heating design. An example of the whole design process including creation, reviewing, optimization, and redesign of curved mold example is presented for results.

Automated mesh division of surfaces of solid objects composed of free-form surfaces.

To establish an integrated CAD system for mechanical design, it is important to connect both geometric modeling technigue and automated numerical simulation technique. This report deals with the technique for the automated mesh division of free-form surfaces, because this technique is indispensable to interface between the above-mentioned techniques. The free-form surfaces are bicubic Bezier surfaces, having 4×4 control points. Each Bezier surface, of which the solid object is composed, is divided into individual triangular meshes. When the mesh division for all surfaces is complete, all triangular meshes are assembled into an appropriate form for numerical simulation. Mesh division is carried out as follows : first the bilinear Bezier surface, having 2×2 control points, is divided into triangular meshes using an automated mesh division program for plane figures ; secondly, the generated mesh points are projected to a u-ν parametric plane. Finally these points are reprojected to a bicubic Bezier surfaces.

Do Design Procedures Fit Designers' Behaviour?

The behaviour of designers of complex industrial production systems is studied. To develop design procedures and CAD systems that are usable to designers, knowledge about design behaviour is necessary. Both literature study and observations from human factors consultancy were used. Systematic consideration of factors that determine the behaviour of designers are illuminated from several points of view. For integration of the different aspects a systems model is considered.It appears that the behaviour of the individual designer, working in a multidisciplinary team is crucial to the design process. Cognitive processes influence the group decision making. It is shown that designers behaviour conflicts with procedures on several points, as a result of which a profound analysis and problem definition may not be performed.

Building an expert CAD system for plant design.

An expert CAD system is developed for supporting the design process of en8ineerin8 pl8nts. The system is built following the general-purpose expert design system which has been developed by the authors. The design of en8ineering plants is characterized by selectin8 candidates for various machinery and equipment which compose the plants based on the experts' knowledge of plant design. In the system, the design knowledge is described in the form of object-oriented knowledge representations which c8n support the design process flexibly, and in a user-friendly way. The system also provides the hybrid functions with numerical computations and graphics, as well as AI techniques, by combining the system programmed with LISP and FORTRAN languages. Through the applications of the developed system to a marine-power design, it is ascertained that the system is effective 8s a design tool assisting designers.

EASE--An Application-Based CAD System for Process Design

A new approach for making process and device simulation tools easier to use is presented. Described is an integrated CAD system for process design in which users select applications rather than tools. CAD simulation methodologies for each application are stored in an applications database and supported by automatic execution modules in the system. A database of "seed files" for initial process parameters are also provided. Both execution automation and the content in user interfaces are tailored to the chosen application to provide for an exceptionally simple and efficient interface, one that minimizes user learning requirements.

ＣＡＤ Ｖ ２ デジタル回路用ＣＡＤシステムの導入と運用

ＣＡＤ Ｖ ２ デジタル回路用ＣＡＤシステムの導入と運用

Plant design on microcomputers

Plant design CAD systems demand sophisticated software because of complex interaction between a database and pictures generated from it. Creation of 3-D images, and the viewing of these shapes is discussed in this paper. A solid modelling approach, combined with a segmented viewfile concept, is described. This solid modelling system is based on a realtime interpreter and the viewing system is an extension of SIGGRAPH CORE and GKS concepts.

金型設計用3次元CADシステムの開発(第2報)

金型設計用3次元CADシステムの開発(第2報)

Design and implementation of a CAD system for cold roll forming

This paper discusses the motivations behind the successful in-house development of a CAD system for toolage design of the cold roll forming process. Emphasis is placed on the need for on-going research efforts in providing information for critical evaluation of design alternatives. The various system development stages are outlined, and results from a recent design exercise are illustrated.

金型設計用3次元CADシステムの開発(第1報)

SMDS which stands for Sony Mold Design Simulator has been developed as a part of an integrated CAD system for injection mold design. This paper describes the prototype system of SMDS, and some examples that are applied to the actual injection mold design are presented. SMDS has been developed to realize the system that can process the geometric data of a mold, based on CSG solid modeler TIPS-1 system. However, there are some future subjects, i.e., physical analysis, simulation of mold flow and so on. These problems should be solved using the model generated in SMDS in the near future. In SMDS, the process of mold design is done by interactive operations and several useful functions for mold design, i.e., shrinkage process, automatic generation of cavity and core, drafting process, and dimensioning and tolerancing, are prepared. Additionally, SMDS has an interface to a 2-D drafting system that can generate complete drafts using interactive operations.

The AT & T technologies unified CAD system for electronic design

We will describe a CAD system used by AT & T Bell Laboratories, AT & T Information Systems, and AT & T Technologies, Inc. for the design, documentation and manufacture of electronic equipment. It is a highly intergrated system designed around a single common data base. Both the system and data base have evolved over a number of years. The goals of the system are to provide CAD tools whose use will yield high quality designs, in short intervals at low cost. The system is made up of two major functional subsystems: EDS—the Engineering Design System, a system for engineers' use in design intent capture, validation and prototype for all packaging levels; IDS—the Interconnection Design System, a physical layout and documentation system for circuit packs and backplanes.

On the solution of inequality systems relevant to IC-layout

Many problems arising in CAD systems for VLSI design, such as layout computation and compaction as well as channel routing, can be reduced to the solution of a certain class of systems of linear inequalities. The complexity of the solution of such systems is studied. The results show that CAD systems manipulating merely the geometry of the layout without changing its topology can be efficiently implemented. However, systems that are also able to change the topology of the layout have to solve hard, i.e., NP-complete, problems.