Showing papers on "Modeling and simulation published in 1983"

Reduced‐order steady‐state and dynamic models for separation processes. Part II. Application to nonlinear multicomponent systems

Abstract: In Part I, a novel method for reducing the order of models for countercurrent staged separation systems was presented. In this paper, the method is applied to the modeling and simulation of nonlinear multicomponent distillation systems. Some additional properties of the model reduction procedure are derived. The accuracy of the approximation is established by comparison of the steady-state profiles and transient responses to that of rigorous dynamic models. The results indicate that the proposed technique is an effective way of reducing the number of equations needed to model stagewise multicomponent separation systems.

Simulation of non-Markovian systems

Abstract: A generalized semi-Markov process provides a stochastic process model for a discrete-event simulation. This representation is particularly useful for non-Markovian systems where it is nontrivial to obtain recurrence properties of the underlying stochastic processes. We develop "geometric trials" arguments which can be used to obtain results on recurrence and regeneration in this setting. Such properties are needed to establish estimation procedures based on regenerative processes. Applications to modeling and simulation of ring and bus networks are discussed.

ROMANS II A two-dimensional process simulator for modeling and simulation in the design of VLSI devices

Abstract: During the past decade considerable effort has been devoted to the development of two-dimensional (2D) device simulators while the development of two-dimensional process simulators, except for the past few years, has been almost nonexistent. To eliminate this lag in the development of 2D process simulators recent research has been directed entirely towards the development of simulators for predicting the thermal redistribution of impurities in bulk device structures; whereas, in the present paper a process simulator, ROMANS II, has been developed which is capable of simulating the redistribution of impurities in both bulk and SOS device structures. All the elements of two-dimensional process modeling which were used to assemble ROMANS II are presented. For example, Runge's approximate procedure for characterizing 2D distributions of ion implants in physical domains of actual device structures is discussed in great detail. Also discussed in great detail are the 2D empirical and phenomenological models used to specify oxide growths on silicon surfaces. A complete formulation of the governing nonlinear boundaryvalue problem for the redistribution of impurities in the physical domain of a device and the corresponding transformation of this problem to a fixed-time invariant rectangular domain by means of a translation-scaling transformation are presented. The numerical algorithm used to solve the nonlinear boundary-value problem in the fixed-time invariant rectangular domain is briefly discussed since a more detailed discussion is given elsewhere. Finally, ROMANS II is utilized to simulate the thermal redistribution of the field, channel, and source/drain implants which were used in fabricating a 1 μmn-channel enhancement mode device. The simulation was carried through the entire device fabrication schedule and the surface topography and corresponding equi-density contours for the net impurity concentration at the end of key process steps are given.

Heat Pump Modeling, Simulation and Design

Abstract: This chapter begins with some introductory comments on the elements of heat pump modeling and simulation. The major portion of the chapter then deals with specific details of steady state modeling and simulation; a brief discussion of transient modeling is also presented. Finally, the chapter concludes with a section on heat pump design.

Chip level modeling and simulation

Abstract: An approach to the modeling of LSI devices at the chip level is described. The complexity of these devices requires that higher level modeling techniques be developed. However, it is impor tant to preserve as much model accuracy as possible when developing high level models. In the approach described here, the chip level models are used to simulate not only device microoperations and internal memory, but also detailed inter face timing requirements. Modeling of such interface timing specifications as set up time, hold time, and minimum pulse width are possible. A modeling example is presented. Opera tion of the complete simulator is described. Two research ap plications of chip level modeling are discussed and an evalua tion of this approach to modeling and simulation is given.

IC process modeling and topography design

Abstract: The device features in the third dimension in VLSI affect packing density and circuit performance. Establishing techniques to characterize and design these nonplanar device features is a major goal of the research on IC process modeling and simulation. Simulation is well accepted as a means of optimizing individual lithography, etching, and deposition processes. It is also well suited for studying the complex tradeoffs between conflicting physical mechanisms in the context of complete multistep process sequences. The success of modeling and simulation has created a demand for more extensive models and new applications. IC process modeling and simulation will not only contribute heavily to technology design but also offers a potential window through the layout role bottleneck for more complete design insight and optimization.

The role of computer modeling and simulation in electric and hybrid vehicle research and development

Abstract: Computer modeling and simulation is widely used in support of electric and hybrid vehicle research and development. Many modeling-assisted studies and assessments, involving candidate technology comparisons, have been performed to provide information for management planning and research decisions. Modeling has also been extensively used in engineering activities including preliminary and final design optimization. A wide range of programs has been developed including small ones for use on hand-held programmable calculators and large programs involving more than 11 000 lines. Many programs exist in the public domain, and two major programs are available on commercial time-sharing systems.

Electric Vehicle Modeling and Simulation.

Abstract: : The forecasting of the performance of electric vehicles has revealed many discrepancies when compared to actual test data. An electric vehicle computer simulation program was developed to ameliorate this deficiency. The approach was to establish a very comprehensive and flexible vehicle model and simulate its operation on a realistic driving cycle. The driving cycle selected was the Federal Urban Driving Sequence. A thorough vehicle model was established that incorporate aerodynamic drag, rolling asistance, both rotational and translational inertial effects, and component by component dynamic power train efficiencies. Battery discharge performance is tracked by a fractional-utilization algorithm with corrections for short-term discharge effects. The simulation compares required power obtained from the driving cycle speed schedule and vehicle model characteristics with the available power at the motor for each time increment of the driving cycle to compute battery fraction used and deviation from the speed schedule when available power is insufficient. These results of the simulation can be used to evaluate an existing vehicle's performance or, if desired, to develop vehicle parameters to obtain a specified performance level. An application of the program to develop a suburban passenger vehicle is included to demonstrate the simulation's utility. A test bed vehicle was constructed and tested to verify the simulation. Additional aspects such as microprocessor based controllers including implementation of an optimal control law were investigated to gain insite into the efficiency and performance trade-offs of such a system.

Wafer Topography Simulation

Abstract: As dimensions of the “classical” planar process are reduced the device features in the third dimension pose major fabrication and performance problems. Establishing techniques to characterize and optimize these non-planar device features is a major goal of research on modeling and simulation. Lithography, etching and deposition models have been established which agree well with experiment. In many cases the dominant physical mechanism is a surface reaction process which can be simulated by a surface advancing algorithm such as the cell, string or ray approach. Prime examples of the usefulness of simulation are in understanding projection printing, step coverage in deposition, wafer planarization and linewidth bias and control for composite process sequences. Simulations for individual IC fabrication processes are being combined in a user oriented program for Simulation And Modeling of Profiles in Lithography and Etching (SAMPLE).

Use Of The SYSCAP 2.5 Computer Analysis Program For Advanced Optical System Design And Analysis

Abstract: The successful development of various electro-optical systems is highly dependent on precise electronic circuit design which must account for possible parameter drift in the various piece parts. The utilization of a comprehensive computer analysis program (SYSCAP) provides the electro-optical system designer and electro-optical management organization with a well-structured tool for a comprehensive system analysis'. As a result, the techniques described in this paper can be readily used by the electro-optical design community. An improved version of the SYSCAP computer program (version 2.5) is presented which inncludes the following new advances: (1) the introduction of a standard macro library that permits call-up of proven mathematical models for system modeling and simulation, (2) the introduction of improved semiconductor models for bipolar junction transistors and p-n junctions, (3) multifunction modeling capability to link signals with very high speed electronic circuit models, (4) high resolution computer graphics (both interactive and batch process) for display and permanent records, and (5) compatibility and interface with ad-vanced engineering work stations. This 2.5* version of the present SYSCAP 2 computer analysis program will be available for use through the Control Data Corporation world-wide Cybernet system in 1983*. This paper provides an overview of SYSCAP modeling and simulation capabilities.

Modeling and simulation in engineering

Abstract: This book presents papers on modeling and simulation in various fields of engineering. Papers are categorized into the following areas: chemical engineering, mechanical engineering, electrical engineering, mechanics and aerospace engineering.