W Stephen

MONSTR: A Complete Thermal Simulator of Electronic Systems

This paper presents a new approach to 3-dimensional thermal simulation of arbitrary electronic systems. This approach is based on the combination of numerical (finite elements and finite differences) and analytical (Fourier series) techniques which are very general and extremely efficient. Complex electronic systems (monolithic ICs, multichip modules, including their packaging) can be analyzed in minutes on PCs to produce a detailed temperature distributions within the system structure. The software system, MONSTR, has been developed and applied to several industrial examples. The results of this analysis are directly entered to the circuit simulator, HSPICE, as the actual temperature for each circuit element and thus an integrated electro-thermal simulation is performed.

A formal basis for design process planning and management

In this paper we present a design formalism that allows for a complete and general characterization of design disciplines and for a unified representation of arbitrarily complex design processes. This formalism has been used as the basis for the development of several prototype CAD meta-tools that offer effective design process planning and management services.

Design assistance for CAD frameworks

Decision-making support based on prediction and advice is a fundamental resource that can be used to reduce search in the design space. The authors discuss the advantages of providing CAD frameworks with a general design assistance facility and the basic methodology that should underlay the implementation of such a facility. A general purpose design assistance metal-tool that successfully realizes the proposed methodology is described. This tool has been integrated into the Odyssey CAD Framework.<<ETX>>

Framework encapsulations: a new approach to CAD tool interoperability

Todays complex leading-edge design processes require the use of multiple CAD tools that operate in multiple frameworks making management of the complete design process difficult. This paper introduces the concept of framework encapsulations: software wrappers around complete CAD frameworks that allow the design data and flow management services of a framework to be utilized by a common design process management tool. This concept has been applied to the Minerva II Design Process Manager, enabling Minerva II to manage the design process across multiple CAD frameworks, and potentially multiple design disciplines.

A modified least squares algorithm for solving sparse n × n sets of nonlinear equations

Abstract In this paper we describe an algorithm for solving sparse n × n sets of nonlinear algebraic equations. This algorithm is like the Levenberg-Marquardt algorithm in that at each iteration the step size taken affects the direction selected to search; this direction lies between the Newton and gradient directions. Unlike the Levenberg-Marquardt schemes the sparsity of the original equations is preserved and thus spare matrix methods can be employed for solving the linearized system of equations.

Towards a Natural Language Interface for CAD

We propose a natural language interface as part of the solution to the problems posed by the continuing increase in the number and sophistication of CAD tools. The advantages of a natural language interface for CAD are numerous, but the complexity of the CAD domain renders most previous work in natural language interfaces of limited utility. We describe a new approach to natural language understanding which we are implementing in an interface currently under development. This approach is based on flexibility, parallelism, and redundancy. The present status of the interface (named Cleopatra) is described, and some imperative improvements are discussed.

A description language for design process management

A language for defining design discipline characteristics is proposed. Design discipline characteristics such as abstraction levels, design object classifications and decompositions, design objectives, and design methodologies can be defined in a simple machine and human readable form. The language, DDDL, has led to the development of a user interface for Minerva II, a design process management tool, which, when configured with a design discipline description, can be used to aid teams of designers in the solution of complex multi-disciplinary design problems. DDDL and user interface examples are presented.

Improved tool and data selection in task management

Task management involves task creation and execution. These are facilitated using a task schema as exemplified in the Hercules Task Manager. Experience with Hercules has shown the task schema to be very useful for task creation, but less than ideal for task resolution, i.e., the selection of tool and data resources to be used in execution. Tool/data interactions often lead to resource selection constraints that cannot be captured using dependency relationships in the schema. We have addressed this by adding conditions to the task schema which use task-level meta-data to constrain resource selection. With examples we show that conditions are useful for handling a wide variety of real constraints.

Natural-Language Interface for CAD: A First Step

Though the ubiquity of CAD tools in state-of-the-art VLSI design has forced the issue of user interfaces for CAD to prominence, one type of user interface that has not been investigated hitherto is the naturallanquage interface. The CAD domain is substantially more complex than the domains for which previous natural-language interfaces have been built. This implies that a natural-language interface for CAD cannot be based on previous approaches to language understanding; a new approach is required. Our approach emphasizes flexibility, parallelism, and redundancy, and is embodied in an interface called Cleopatra. Ultimately, Cleopatra will be an interface for an ¿integrated design environment.¿ As a first step towards that goal, but also as a useful tool in its own right, Cleopatra currently deals with circuit-simulation post-processing.

Planning and Managing Multi-disciplinary and Concurrent Design Processes

It is time to move beyond the development of CAD tools that only aid designers in solving specific synthesis, analysis, and/or optimization design problems, but to develop tools that aid designers in planning and managing the increasingly complex design process itself. Specifically, we need to develop meta-tools capable of capturing design methodologies, and of intelligently making use of such methodologies while planning and managing the design process.