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Using Mathematica To Aid Simulation Analysis, Paul Savory

Department of Industrial and Management Systems Engineering: Faculty Publications

As computer power has increased, so has the capability of software developers to write programs that assist people with time-consuming tasks. Mathematica is such a program. The objective of this paper is to demonstrate how Mathematica, a symbolic programming environment, can be used to aid simulation analysis. In addition to a general discussion of Mathematica’s uses, advantages, and disadvantages, several examples will be presented. The examples include using Mathematica for distribution fitting, queueing analysis, random number generation, and creating a surface plot for optimization.

Acuta Enews December 1995, Vol. 24, No. 12

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A Psychological Perspective On Service Segmentation Models: The Significance Of Accounting For Consumers' Perceptions Of Waiting And Service, Ziv Carmon, J. George Shanthikumar, Tali F. Carmon

Industrial and Manufacturing Engineering

We examine how service should be divided and scheduled when it can be provided in multiple separate segments. We analyze variants of this problem using a model with a conventional function describing the waiting cost, that is modified to account for some aspects of the psychological cost of waiting in line. We show that consideration of the psychological cost can result in prescriptions that are inconsistent with the common wisdom of queuing theorists derived according to the conventional approach (e.g., equal load assignments). More generally, our intention in this paper is to illustrate that aspects of the psychological cost of …

Acuta Enews November 1995, Vol. 24, No. 11

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Voice Cellular Services at CMU

CTI for Universities Network 2000 at UTMB

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Acuta Enews October 1995, Vol. 24, No. 10

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Disaster Recovery: Part ll

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A Simulation Study Of Quality Index In Machine-Component Grouping, Hamid Seifoddini, Manocher Djassemi

Industrial Technology and Packaging

Simulation modeling is employed to determine the effectiveness of quality index in screening machine-part matrices for the development of cellular manufacturing systems.

Acuta Enews September 1995, Vol. 24, No. 9

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Awards presented at 24th Annual Conference

New Board of Directors looks forward to 1996

Board Report

Welcome New Members

Host needed for Winter Seminar

President's Message

Driving smart on the Info Highway

Traffic Control For Automated Highway Systems: A Conceptual Framework, H.-S. Jacob Tsao

Faculty Publications

This paper proposes a conceptual framework for designing a traffic control scheme. It adopts a top-down approach to defining major design steps starting with high-level feature definition. With the desired features defined, the top-down approach then identifies and defines moves and related planning and movement functions that are required for supporting the desired features. The paper takes a systems view and identifies the safety issues regarding the movement coordination of the large number of vehicles on an Automated Highway System (AHS).

Acuta Enews August 1995, Vol. 24, No. 8

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ISDN at MSU

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Acuta Enews July 1995, Vol. 24, No. 7

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Board report

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Wiring today for tomorrow

Card technology

DC at a glance

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Acuta Enews July 1995, Vol. 24, No. 7

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Board report

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Wiring today for tomorrow

Card technology

DC at a glance

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Acuta Enews June 1995, Vol. 24, No. 6

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Board report

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Charles Co. Community College's telecommuting project

Brock's campus ID card

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Acuta Enews May 1995, Vol. 24, No. 5

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Board report

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Benchmarks for your telecom operation

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Acuta Enews April 1995, Vol. 24, No. 4

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Directory updates

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Acuta Enews March 1995, Vol. 24, No. 3

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Info Superhighway grant

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A Discrete Single Server Queue With Markovian Arrivals And Phase Type Group Services, Attahiru Sule Alfa, K. Laurie Dolhun, Srinivas R. Chakravarthy

Industrial & Manufacturing Engineering Publications

We consider a single-server discrete queueing system in which arrivals occur according to a Markovian arrival process. Service is provided in groups of size no more than M customers. The service times are assumed to follow a discrete phase type distribution, whose representation may depend on the group size. Under a probabilistic service rule, which depends on the number of customers waiting in the queue, this system is studied as a Markov process. This type of queueing system is encountered in the operations of an automatic storage retrieval system. The steady-state probability vector is shown to be of (modified) matrix-geometric …

Acuta Enews February 1995, Vol. 24, No. 2

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Merits Of The Production Volume Based Similarity Coefficient In Machine Cell Formation, Hamid Seifoddini, Manocher Djassemi

Industrial Technology and Packaging

In this paper, two types of similarity coefficients are compared: (1) the Jaccard's coefficient and (2) the production volume based coefficient. Each is used to form a cellular manufacturing system whose performance will be used as a measure of effectiveness of the similarity coefficient. The sum of intercellular and intracellular material handling costs is used as a criterion for performance evaluation.

Creep Fatigue, Part Iii: Diercks Equation: Modification And Applicability, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

Creep-fatigue data of low allow steels were compiled from international sources, and trends in creep-fatigue behavior were identified in Paper I. Methods of life prediction and their trends were examined in Paper II with respect to compiled data. Diercks equation, a multivariate creep-fatigue life extrapolation equation, for SS, 304, in terms of strain range, temperature, hold time and strain rate parameters is modified and extended to the life prediction of low alloy steels in this paper.

Applicability Of Modified Diercks Equation With Nrim Data, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

The applicability of the modified Diercks equation (MDE) was assessed with elevated temperature low cycle fatigue (ETLCF) data generated by the National Research Institute for Metals (NRIM) for lCr-Mo-V, 1.25Cr-Mo, 2.25Cr-Mo and 9Cr-lMo steels respectively. The modified Diercks equation was assessed with data generated with symmetrical, slow-fast and hold-time waveforms for low alloy steels. The following characteristics were observed: Symmetrical waveforms: Five strain rates were used with these waveforms where predicted life was by a factor of ± x2 for 77%, 87%, 82% and 92% of data points for lCr-Mo-V, 1.25Cr-Mo, 2.25Cr-Mo and 9CrlMo steels respectively. Slow-fast waveforms: Diercks equation …

Issues In Developing An Undergraduate Simulation Course, Paul Savory

Department of Industrial and Management Systems Engineering: Faculty Publications

Experience in developing an undergraduate simulation course is described. The course introduces the philosophies, principles, and methodologies for discrete-event simulation modeling. Strategy in choosing the course simulation software is discussed, plus important areas of teaching emphasis are highlighted.

Simulation Project Characteristics In Industrial Settings, Paul Savory

Department of Industrial and Management Systems Engineering: Faculty Publications

In a survey of practitioners of discrete-event simulation from industry and research institutes who "build models for money," we asked about project goals, user backgrounds and training, organizational types and activities, software and hardware choices, modeling team composition, and effort allocation within a modeling project. We found that (1) only about half of the practitioners have three or more years experience, (2) many academics feel strongly affiliated with their industry clients rather than with their university employers, (3) shop-floor supervisors rarely lead simulation projects, even though their knowledge of the system may be unparalleled, (4)simulation models are generally described as …

Acuta Enews January 1995, Vol. 24, No. 1

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Telecom Resources Library Update

Developing a campus telecom plan

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Using Matlab To Illustrate The 'Phenomenon Of Aliasing', Sol Neeman, Ph.D.

Engineering Studies Faculty Publications and Creative Works

The phenomenon of aliasing is important when sampling analog signals. In cases where the signal is bandlimited, one can avoid aliasing by ensuring that the sampling rate is higher than the Nyquist rate . But in cases where the signal is not bandlimited , aliasing is unavoidable if the signal is not filtered before it is sampled. It is then crucial to understand the phenomenon in order to estimate the distortion generated when the signal is reconstructed from its samples. Using the software package MATLAB by MathWorks, Inc ., two examples are presented. The first is a pure sinusoid which …

A Staggered-Diamond Design For Automated/Manual-Hov Highway-To-Highway Interchanges And Constraints On Ahs Design For Accommodating Automated Highway Change, Jacob Tsao

Faculty Publications

This paper consists of two components. The First component addresses a key AHS infrastructure support issue—providing eight extra connector ramps, in addition to the eight existing highway-to-highway connector ramps for the conventional manual traffic, at a highway-to-highway interchange for accommodating continuous automated driving from one highway to the crossing highway. The proposed staggered-diamond design requires only four, instead of eight, separate structures and hence greatly increases the feasibility of AHS infrastructure support. However, the reduced infrastructure complexity at such interchanges could still constrain considerably the design, operation and evolution of AHS. This is the focus of the second component. The …

Stage Definition For Ahs Deployment And An Ahs Evolutionary Scenario, Jacob Tsao

Faculty Publications

Pros and cons of various mature Automated Highway Systems (AHS) have been a subject of intense study. However, such discussions are nothing but intellectual exercises unless the issue of how to evolve, in a planned and managed fashion, the current highway systems towards these mature AHS is also addressed. Since full functionality of a mature AHS cannot be realized suddenly, discrete functional steps must be identified and optimized. This paper defines an evolutionary stage towards a mature AHS as any discernible functional increment whose realization may encounter considerable difficulties requiring a significant amount of conscious effort to overcome. A good …

Creep Fatigue, Part I: Compilation Of Data And Trends In The Creep-Fatigue Behavior Of Low Alloy Steels, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

This paper describes an attempt to compile the creep-fatigue data of low alloy steels. In part I, international data have been collected to compare the variability that exists in a particular low alloy steel when characterized in different laboratories. From this work of compilation, trends in the creep-fatigue behavior of low alloy steels have been identified in Part II of this paper and a review of life prediction methods and assessments will be discussed in subsequent papers. The creep-fatigue behavior, in general, improved with the increase in chromium content; however, when additional alloying elements were added to a standard alloy …

Creep Fatigue, Part Ii: Creep Fatigue Life Prediction: Methods And Trends, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

Creep-fatigue data of low allow steels were compiled from international sources, and trends in creep-fatigue behavior were identified in Paper I. This paper reviews the methods of creep-fatigue life prediction that were assessed from the compiled data. The methods reviewed in this paper are phenomenological in nature. However, an empirical method has also been discussed which offers very high reliability of the prediction capability. Various test requirements, from which material parameters are determined for each method, have been tabulated. No single method has been generalized as a best method of life prediction for all types of creep-fatigue test conditions.

Creep-Fatigue Life Prediction - A Ductility Model, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

Creep-fatigue life prediction methods are briefly reviewed. Phenomenological methods of life prediction are very popular, since they use several test and metallographic parameters in model formulation. They also require numerous test parameters determined from specialized tests. Requirements of phenomenological methods have been summarized. Ductility measurement and modeling aspects have been reviewed. A new model has been developed with the assumption that with increasing fatigue cycles the ductility gradually decreases and the specimen fails as a result of exhaustion of ductility. This has been achieved in terms of dynamic viscosity (product of stress and cycle time), equated with material toughness, which …

Linearly-Constrained Entropy Maximization Problem With Quadratic Costs And Its Applications To Transportation Planning Problems, Shu-Cherng Fang, Jacob Tsao

Faculty Publications

Many transportation problems can be formulated as a linearly-constrained convex programming problem whose objective function consists of entropy functions and other cost-related terms. In this paper, we propose an unconstrained convex programming dual approach to solving these problems. In particular, we focus on a class of linearly-constrained entropy maximization problem with quadratic cost, study its Lagrangian dual, and provide a globally convergent algorithm with a quadratic rate of convergence. The theory and algorithm can be readily applied to the trip distribution problem with quadratic cost and many other entropy-based formulations, including the conventional trip distribution problem with linear cost, the …