Industrial and Management Systems Engineering Faculty Publications

A Simplified Method for the Bilinear s-z Transformation

Dan M. Scott — Mon, 14 Mar 2011 14:03:25 PDT

A new technique for performing the bilinear transformation of polynomials is presented. The technique is both simple to understand as well as efficient in its computer implementation. The key to the method is the way in which the successive derivatives of a particular polynomial are computed. A simple recursion formula is used which can be done either by hand, if desired, or by computer. The order of complexity of the algorithm is found to be O(n²), while storage requirements are O(n), where n is the degree of the polynomial. The new method will handle completely general bilinear transformations. A computer implementation is presented which was found to be satisfactory for both precision and speed.

Design and Implementation of a Non-Proprietary Campus Energy Management and Control System (EMCS)

Stefan Newbold et al. — Mon, 14 Mar 2011 14:00:03 PDT

The Energy Management and Control System (EMCS) used at the University of Nebraska - Lincoln (UNL) is unique in that system hardware and software has been developed primarily in-house. UNL has a successful track record with this approach stretching back more than twenty years.

This paper presents an industry experience report describing the high-level design and development of the latest version of this EMCS. This system is now being deployed on campus.

We discuss aspects of our EMCS that enhance usability, fault tolerance, and security. Our system is unique in that it was primarily developed using non-proprietary, opensource software building blocks and software construction tools. This approach provides a framework for potential collaboration with others who are interested in expanding this system beyond UNL.

LPSOLVER: A Linear Program Solving Package for Educational and Instructional Modeling Applications

Paul Savory et al. — Thu, 25 Feb 2010 11:08:52 PST

LPSOLVER is a computer program developed to be a learning tool for students studying linear programming. This technical paper contains and overview of what LPSOLVER is and how to use it. The program allows one to enter linear programs in three different formats which are discussed in Section IV. Described in Section VI are the two methods available for solving linear programs. Other features of LPSOLVER are discussed in Section VII. Appendix A describes all the various files that LPSOLVER uses/creates. A listing of error messages is given in Appendix B. Information about how the program was implement is contained in Appendix C.

Introduction to IntelliSIM 1.0

Paul Savory — Wed, 24 Feb 2010 08:30:42 PST

IntelliSIM is a prototype for a new generation of knowledge-based simulation tool that has been developed by the Systems Simulation Laboratory at Arizona State University. This tool is a computer environment that allows non-simulation trained modelers to predict the performance of a manufacturing system for which the necessary data is available. The system provides predictive data on such items as throughput time, queue levels, equipment utilization, reactions to machine failures, etc. With IntelliSIM, the benefits of discrete-event simulation can be exploited without requiring the high level of expertise necessary to successfully conduct a sound simulation study. The approach offered with IntelliSIM is one which will offer substantial savings over currently available simulation tools. This document is Version 1 (1992) of the user manual for the IntelliSIM software.

Introduction to IntelliSIM 2.0

Paul Savory — Wed, 24 Feb 2010 08:30:40 PST

IntelliSIM is a prototype for a new generation of knowledge-based simulation tool that has been developed by the Systems Simulation Laboratory at Arizona State University. This tool is a computer environment that allows non-simulation trained modelers to predict the performance of a manufacturing system for which the necessary data is available. The system provides predictive data on such items as throughput time, queue levels, equipment utilization, reactions to machine failures, etc. With IntelliSIM, the benefits of discrete-event simulation can be exploited without requiring the high level of expertise necessary to successfully conduct a sound simulation study. The approach offered with IntelliSIM is one which will offer substantial savings over currently available simulation tools. This document is Version 2 (1993) of the user manual for the IntelliSIM software.

A Robust Aggregation Approach To Simplification Of Manufacturing Flow Line Models

Paul Savory — Fri, 19 Feb 2010 12:03:50 PST

One of the more difficult tasks facing a modeler in developing a simulation model of a discrete part manufacturing system is deciding at what level of abstraction to represent the resources of the system. For example, questions about plant capacity can be modeled with a simple model, whereas questions regarding the efficiency of different part scheduling rules can only be answered with a more detailed model. In developing a simulation model, most of the actual features of the system under study must be ignored and an abstraction must be developed. If done correctly, this idealization provides a useful approximation of the real system. Unfortunately, many individuals claim that the process of building a simulation model is an “intuitive art.” The objective of this research is to introduce aspects of “science” to model development by defining quantitative techniques for developing an aggregate simulation model for estimating part cycle time of a manufacturing flow line. The methodology integrates aspects of queueing theory, a recursive algorithm, and simulation to develop the specifications necessary for combining resources of a flow line into a reduced set of aggregation resources. Experimentation shows that developing a simulation model with the aggregation resources results in accurate interval estimates of the average part cycle time.

Expected Time in System for M/G/1 Queue

Paul Savory — Sat, 13 Feb 2010 11:20:47 PST

Queueing theory focuses on study waiting lines though the use of mathematical or queueing models. Queueing models provide numerous estimates of the steady-state performance measures of a queue for systems which meet the required assumptions. This demonstration, written in Mathematica, allows one to calculate the steady-state expected waiting time in an M/G/1 queue for a range of arrival rates. The M/G/1 queue models the situation with exponential (random arrivals), a general service time distribution, and one server.

Probability of Zero in a System for an M/M/S Queue

Paul Savory — Fri, 12 Feb 2010 13:51:06 PST

Queueing theory focuses on study waiting lines though the use of mathematical or queueing models. Queueing models provide numerous estimates of the steady-state performance measures of a queue for systems which meet the required assumptions. This demonstration, written in Mathematica, allows one to view the probability of zero people in an M/M/S queueing system for a varying number of servers and a range of utilization values.

Inquiry into the College Classroom: A Journey Toward Scholarly Teaching

Paul Savory et al. — Fri, 12 Feb 2010 13:51:05 PST

An essential companion for university faculty interested in conducting scholarly inquiry into their classroom teaching, this practical guide presents a formal model for making visible the careful, difficult, and intentional scholarly work entailed in exploring a teaching question. As a how-to guide, this is an invaluable resource for planning and conducting classroom research—formulating questions and hypotheses, defining a data collection methodology, collecting data, measuring the impact, and documenting the results. Inquiry Into the College Classroom is filled with richly illustrative examples that highlight how university faculty from a range of academic disciplines have performed scholarly inquiries into their teaching and leads faculty on a journey that includes:

- Developing a formal model for structuring the exploration of a classroom inquiry question - Providing a practical and useful guide for faculty interested in exploring teaching and learning challenges - Detailing faculty experiences in measuring specific changes in student learning or perspectives - Demonstrating how to document classroom inquiry in a form to be shared, used, and reviewed by other faculty - Sharing useful and practical suggestions for getting started with a classroom inquiry - Highlighting different models for disseminating classroom inquiry work - Linking classroom inquiry to larger conversations about the scholarship of teaching and learning

Making Teaching and Learning Visible: Course Portfolios and the Peer Review of Teaching

Daniel Bernstein et al. — Fri, 12 Feb 2010 13:51:04 PST

With higher education’s refocus over the last three decades on bringing greater recognition and reward to good teaching, the idea of peer review has gained popularity. One tool for documenting and reflecting on the quality of teaching and student learning is a course portfolio. A course portfolio captures and makes visible the careful, difficult, and intentional scholarly work of planning and teaching a course.

Illustrated through examples of course portfolios created during a four-year project on peer review of teaching, this book demonstrates how faculty can integrate well-designed peer review into their daily professional lives, thus improving their teaching by incorporating a means for assessment and collaboration and revealing the student learning that happens with effective teaching within an institutional reward systems.

This book offers a model of peer review intended to help faculty document, assess, reflect on, and improve teaching and student learning through the use of a course portfolio. It features a rich collection of materials—including four dozen exhibits to help assemble a portfolio, reviewers’ comments, and reflections drawn from more than 200 professors and portfolio authors in various disciplines and institutions—that faculty can use to develop their course portfolios to be used in their peer review of teaching.

Inquiry into the College Classroom

Paul Savory et al. — Mon, 08 Feb 2010 20:29:39 PST

Are our students learning? Are they developing? Are we having an impact? These questions are only a small sample of those that faculty ask before, during, and after each course that they teach. Faculty often attempt to answer such questions using the evidence they have—student remarks during class and office hours, student performance on examinations or homework assignments, student comments solicited via teaching evaluations, and their own classroom observations. While these forms of evidence can be useful, such informal assessments also can be misleading, particularly because they are generally not systematic or fully representative.

Combining Activity-Based Costing with the Simulation of a Cellular Manufacturing System

Paul Savory et al. — Mon, 08 Feb 2010 20:29:38 PST

Discrete-event simulation is one of the most effective techniques for analyzing a manufacturing system. Unfortunately, little attention is given to using simulation models to estimate the economic impact of a proposed system configuration. This paper defines how activity-based costing (ABC) concepts can be incorporated into a discrete-event simulation model. Special emphasis is on demonstrating how decision making can be aided by having the simulation create a detailed “Bill of Activity” describing costs associated with manufacturing a part. The integration of ABC and simulation is illustrated by evaluating the impact of a proposed manufacturing cell configuration. The additional costing information aids in cell design, determining part sequencing and scheduling, and provides a quick evaluation of product mix changes for a part family.

An Aggregation Procedure for Simulating Manufacturing Flow Line Models

Paul Savory et al. — Mon, 08 Feb 2010 20:29:38 PST

We develop a formal method for specifying an aggregate discrete-event simulation model of a production flow line manufacturing system. The methodology operates by aggregating production stations or resources of a flow line. Determining the specifications for representing the aggregated resources in a simulation model is the focus of our presentation. We test the methodology for a set of flow lines with exponentially distributed arrival and service times. Comparisons between analytical and simulation results indicate the aggregation approach is quite accurate for estimating average part cycle time.

A Multithreaded Scheduler for a High-Speed Simulator

Gene Saghi et al. — Mon, 08 Feb 2010 20:29:37 PST

The Cassini spacecraft is on its journey to Saturn to perform a close-up study of the Saturnian system; its rings, moons, magneto-sphere, and the planet itself. Sequences of commands will be sent to the spacecraft by ground personnel to control every aspect of the mission. To validate and verify these command sequences, a bit-level, high-speed simulator (HSS) has been developed. To maximize performance, the HSS is implemented with multiple threads and runs on a multiprocessor system. A key component of the HSS is the scheduler, which controls the execution of the simulator. The general framework of the scheduler can be adapted to solve a wide variety of scheduling problems. The architecture of the scheduler is presented first, followed by a discussion of issues related to performance and multiple threads. Second, the avoidance of deadlocks and race conditions is discussed and an informal proof for the absence of both in the scheduler is described. Finally, a study of various scheduling policies is provided

Combining Activity-Based Costing with the Simulation of a Cellular Manufacturing System

Paul Savory et al. — Mon, 08 Feb 2010 20:29:36 PST

This paper presents an integrated simulation and activity-based management approach for determining the best sequencing scheme for processing a part family through a manufacturing cell. The integration is illustrated on a loop or U-shaped manufacturing cell and a part family consisting of four part types (A, B, C, and D). Production requirements for the cell demand that part batches be processed one type at a time. For example, all part A’s are processed until weekly demand is met, then part B’s, etc. The objective of this example is to determine the best part sequence (e.g., ABCD, DCBA or CABD). In addition to traditional measures, the simulation model produces detailed activity-based costing estimates. Analysis of cost and performance parameters indicates part sequence CDBA provides the best overall choice. This sequence achieves a low per unit manufacturing cost, minimizes average time in the system and in-cell inventory cost, and maximizes unused production capacity. Although the scope of this effort was restricted to a small scale manufacturing cell, the costing concepts have general applicability to manufacturing operations at all levels.

Guidelines for Using Process Mapping to Aid Improvement Efforts

Paul Savory et al. — Mon, 08 Feb 2010 20:29:35 PST

Process mapping is an easy-to-visualize method for people to analyze and agree on the most efficient routes for reengineering or improving a process. It aids in determining redundant tasks, uncovering hidden interactions between processes and people, and focusing on the processes that serve customers, improve quality, and generate income. This paper presents guidelines for using process mapping as an improvement tool. It is based on the authors’ experiences in aiding a variety of healthcare, service, and manufacturing companies.

A Simulation Based Experiment For Comparing AMHS Performance In A Semiconductor Fabrication Facility

Gerald Mackulak et al. — Mon, 08 Feb 2010 20:29:34 PST

As the cost and complexity of constructing a semiconductor fabrication facility increases, responsive tools are needed for designing and planning its operations. Discrete-event simulation paired with design of experiments is an effective combination. This article demonstrates how simulation in combination with design of experiments is used to compare the intrabay layout of two automated material handling systems. The difference in stocker robot utilization, number of vehicle moves per hour, and average delivery time for the two intrabay layouts will be compared using a fractional factorial experimental design. The study demonstrates that the distributed storage option is preferable for maximizing manufacturing performance. Although the scope of this effort was restricted to a single situation, the solution procedure has general applicability as a tutorial for practitioners.

A Template-Based Data Specification Framework For Modeling Physical Security Systems

Ashu Guru et al. — Mon, 08 Feb 2010 20:29:33 PST

Simulation studies often fail to provide any useful results due to its success being highly dependent on the skills of the analyst to understand a system and then correctly identify all the required data parameters and dependent variables. This paper describes a template-based framework to help identify and specify the components and data parameters for developing models of physical security systems. The layered framework consists of fifteen templates built on top of fourteen data primitives representing 119 data parameters. The modeling framework has been programmed as an internet-based web application and is simulation language independent. The usefulness of the framework was tested and shown to have a significant impact on improving the identification of system components and their associated data parameters

Road Rescue Implements a Continuous Process Improvement Framework

John Olson et al. — Mon, 08 Feb 2010 20:29:32 PST

Continuous improvement programs traditionally focus on making small incremental improvements to a system. Unfortunately, their success can be limited due to the rapid changing environment within which most small companies operate. Improvement efforts should be flexible enough to capitalize on incremental and radical changes to a system. This paper presents a case analysis of how Road Rescue, an ambulance manufacturer, uses a continuous improvement framework to capitalize on both radical and incremental improvement opportunities. Results include a 10% increase in throughput, reduced cycle time of 44%, increased customer satisfaction, and higher quality.

Cycle Time Estimation for Simulating a Tandem Queueing Systems Using Aggregation Techniques

Paul Savory et al. — Mon, 08 Feb 2010 20:29:31 PST

One approach to simulating a single-server tandem queuing system is to explicitly model each of the production stages. In this paper, we apply queueing theory, a recursive algorithm, and composite random number sampling to develop an equivalent aggregate representation consisting of only a single production stage. Preliminary test results indicate that the aggregation works well for estimating the mean and variability of the total cycle time.