Open Access. Powered by Scholars. Published by Universities.®

Operations Research, Systems Engineering and Industrial Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Series

Iowa State University

Discipline
Keyword
Publication Year
Publication

Articles 571 - 596 of 596

Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering

Development Programs For One-Shot Systems Using Multiple-State Design Reliability Models, Suntichai Shevasuthisilp, Stephen B. Vardeman Jan 2004

Development Programs For One-Shot Systems Using Multiple-State Design Reliability Models, Suntichai Shevasuthisilp, Stephen B. Vardeman

Industrial and Manufacturing Systems Engineering Publications

Design reliability at the beginning of a product development program is typically low, and development costs can account for a large proportion of total product cost. We consider how to conduct development programs (series of tests and redesigns) for one-shot systems (which are destroyed at first use or during testing). In rough terms, our aim is to both achieve high final design reliability and spend as little of a fixed budget as possible on development. We employ multiple-state reliability models. Dynamic programming is used to identify a best test-and-redesign strategy and is shown to be presently computationally feasible for at ...


Economic Simulation Modeling Of Reprocessing Alternatives For Corn Masa Byproducts, Kurt A. Rosentrater, Thomas L. Richard, Carl J. Bern, Rolando A. Flores Nov 2003

Economic Simulation Modeling Of Reprocessing Alternatives For Corn Masa Byproducts, Kurt A. Rosentrater, Thomas L. Richard, Carl J. Bern, Rolando A. Flores

Agricultural and Biosystems Engineering Publications

Increasing production of corn masa for tortillas, chips, and related snack foods is resulting in large quantities of organic residuals requiring environmentally sound management. These byproduct streams appear suitable for use as livestock feed material, thus eliminating landfilling costs. Possibilities for developing livestock feed include direct shipping to livestock feeding facilities, blending prior to shipping, extrusion processing, pellet mill processing, and dehydration. To assess the viability of these options for reprocessing masa byproducts as livestock feed materials, an economic model was developed and applied to each of these alternatives. Through a series of simulation runs with this model, it was ...


An Active Learning Environment In An Integrated Industrial Engineering Curriculum, Frank Peters, John K. Jackman, Sarah M. Ryan, Sigurdur Olafsson Oct 2003

An Active Learning Environment In An Integrated Industrial Engineering Curriculum, Frank Peters, John K. Jackman, Sarah M. Ryan, Sigurdur Olafsson

Industrial and Manufacturing Systems Engineering Conference Proceedings and Posters

We are developing a new learning environment that supports a suite of interrelated modules based on real-world scenarios. The primary goals of the project are to integrate industrial engineering courses, improve students’ information technology skills, and enhance students’ problem solving skills. In particular, metacognitive abilities will be strengthened as students apply domain knowledge, data, methods and software tools while monitoring their own solution processes. This paper presents the design of two modules that have been developed.


Discrete Event Simulation Implemented In A Virtual Environment, Jason Kelsick, Lori Buhr, Cheryl Moller, Judy M. Vance Sep 2003

Discrete Event Simulation Implemented In A Virtual Environment, Jason Kelsick, Lori Buhr, Cheryl Moller, Judy M. Vance

Mechanical Engineering Publications

Virtual reality (VR) technology provides a human-computer interface that allows participants to interact naturally with digital objects which are represented as three-dimensional images that occupy positions in a three-dimensional world. Related to problems of engineering design and manufacturing, this new technology offers engineers the ability to work with computer models in a three-dimensional, immersive environment. This paper describes a virtual reality application where the results of a discrete event simulation of a manufacturing cell are integrated with a virtual model of the cell to produce a virtual environment. The program described in this paper, the VRFactory, combines results from a ...


Data Mining For Production Scheduling, Sigurdur Olafsson Jan 2003

Data Mining For Production Scheduling, Sigurdur Olafsson

Industrial and Manufacturing Systems Engineering Conference Proceedings and Posters

Data mining is a fast growing field and many industrial engineering applications generate large amounts of data to which data mining techniques can be applied. In this paper we develop a data mining framework for production scheduling. This involves preprocessing of historic schedules into an appropriate data file, discovery of key scheduling concepts, and representation of the data mining results in a way that enables its use for job scheduling.


Analysis Of Delayed Product Differentiation Under A Conwip Policy, Heedong Kim, Sarah M. Ryan Jan 2003

Analysis Of Delayed Product Differentiation Under A Conwip Policy, Heedong Kim, Sarah M. Ryan

Industrial and Manufacturing Systems Engineering Conference Proceedings and Posters

Delayed product differentiation (DPD) increases manufacturers’ competitiveness by enabling faster responses to demand changes and has been shown to require less work in process (WIP) in base-stock systems. We model a system of two products using three CONWIP loops to represent the common processes and the differentiated processes for each product. DPD converts some differentiated processes to common ones. A nonlinear programming (NLP) model can determine kanban counts for each loop to achieve specified throughput bounds. Because these bounds are not tight, a heuristic algorithm starts from the NLP solution and adjusts the kanbans according to simulation. The results indicate ...


The Electronic Learning Portal: An Active Learning Environment For Information Technology Across The Curriculum, John K. Jackman, Sigurdur Olafsson, Frank E. Peters, Sarah M. Ryan Jan 2003

The Electronic Learning Portal: An Active Learning Environment For Information Technology Across The Curriculum, John K. Jackman, Sigurdur Olafsson, Frank E. Peters, Sarah M. Ryan

Industrial and Manufacturing Systems Engineering Conference Proceedings and Posters

We are developing a new system that supports a suite of interrelated computer modules based on real-world scenarios. The primary goals of the project are to integrate industrial engineering courses, improve students’ information technology skills, and enhance students’ problem solving skills. In particular, metacognitive abilities will be strengthened as students apply domain knowledge, data, methods and software tools while monitoring their own solution processes. This paper presents some of our results from a pilot study in a large engineering economic analysis course.


Scalable Optimization-Based Feature Selection Using Random Sampling, Jaekyung Yang, Sigurdur Olafsson Jan 2003

Scalable Optimization-Based Feature Selection Using Random Sampling, Jaekyung Yang, Sigurdur Olafsson

Industrial and Manufacturing Systems Engineering Conference Proceedings and Posters

We analyze an optimization-based approach called the NP-Filter for feature selection and show how the scalability of this method can be improved using random sampling of instances from the training data. The NP-Filter has attractive theoretical properties as the final solution quality can be quantified and it is flexible in terms of incorporating various feature evaluation methods. We show how the NP-Filter can automatically adjust to the randomness that occurs when a sample of training instances is used, and present numerical results that illustrate both this key result and the scalability improvement that are obtained.


Allocation And Inventory Policies For Reels In Printed Circuit Board Assemblies, Abhishek Bandyopadhyay, Sachin Sulakhe, Sasidhar Malladi, Viveck Rao, Krishna Lakshminarasimhan, K. Jo Min Jan 2003

Allocation And Inventory Policies For Reels In Printed Circuit Board Assemblies, Abhishek Bandyopadhyay, Sachin Sulakhe, Sasidhar Malladi, Viveck Rao, Krishna Lakshminarasimhan, K. Jo Min

Industrial and Manufacturing Systems Engineering Conference Proceedings and Posters

In Printed Circuit Board (PCB) assemblies, various types of reels loaded with different components are extensively utilized. We examine the inventory and allocation policies across assembly lines when the number and size of the reels substantially affect the assembly efficiency (e.g., when the number of available slots in a chip shooter is relatively limited). Critical features of the policies are illustrated via numerical examples.


Information Technology Based Active Learning: A Pilot Study For Engineering Economy, Sigurdur Olafsson, Mary Huba, John K. Jackman, Frank E. Peters, Sarah M. Ryan Jan 2003

Information Technology Based Active Learning: A Pilot Study For Engineering Economy, Sigurdur Olafsson, Mary Huba, John K. Jackman, Frank E. Peters, Sarah M. Ryan

Industrial and Manufacturing Systems Engineering Conference Proceedings and Posters

We have recently designed a learning environment to add practical problem solving, increased information technology content, and active learning to industrial engineering courses. In particular, we have successfully implemented and tested a computer-based module for an undergraduate engineering economy course. In this module, students are required to formulate the problem, devise a plan of action, and derive a final solution using the domain knowledge acquired in class. In addition to improving understanding of the course material, the module is also designed to improve more general cognitive skills and specifically to enhance the metacognitive ability of the participating students. A prototype ...


Total Wip And Wip Mix For A Conwip Controlled Job Shop, Sarah M. Ryan, F. Fred Choobineh Jan 2003

Total Wip And Wip Mix For A Conwip Controlled Job Shop, Sarah M. Ryan, F. Fred Choobineh

Industrial and Manufacturing Systems Engineering Publications

A planning procedure to set the constant level of Work-In-Process (WIP) for each product type in a job shop operated under CONWIP control is developed. We model the job shop as a single chain multiple class closed queuing network. Given a specified product mix and a total WIP, a nonlinear program bounds the throughput of the network and optimizes the WIP mix. We identify the minimum total WIP that is guaranteed to yield throughput near the maximum possible for the specified product mix and set individual WIP levels by multiplying the optimal WIP mix proportions by the minimum total WIP ...


Capacity Expansion With Lead Times And Autocorrelated Random Demand, Sarah M. Ryan Jan 2003

Capacity Expansion With Lead Times And Autocorrelated Random Demand, Sarah M. Ryan

Industrial and Manufacturing Systems Engineering Publications

The combination of uncertain demand and lead times for installing capacity creates the risk of shortage during the lead time, which may have serious consequences for a service provider. This paper analyzes a model of capacity expansion with autocorrelated random demand and a fixed lead time for adding capacity. To provide a specified level of service, a discrete time expansion timing policy uses a forecast error-adjusted minimum threshold level of excess capacity position to trigger an expansion. Under this timing policy, the expansion cost can be minimized by solving a deterministic dynamic program. We study the effects of demand characteristics ...


Capacity Expansion For A Loss System With Exponential Demand Growth, Alexander Simampo, Sarah M. Ryan Jan 2003

Capacity Expansion For A Loss System With Exponential Demand Growth, Alexander Simampo, Sarah M. Ryan

Industrial and Manufacturing Systems Engineering Publications

We study a loss system to forecast the demand for capacity based on the forecast demand for service and a specified service level. A little-used property of the Erlang loss formula allows the linear transformation of demand for service into demand for capacity. Next, given the forecast demand for capacity, we approximate a long-run optimal capacity expansion policy by optimizing over successively longer finite time horizons. Analytical formulas together with regression analysis show the significance of the number of potential customers, frequency and duration of their requests for service, and the specified service level on the demand for capacity. Numerical ...


A New Analytical Evaluation Model For Kanban Controlled Systems With Fork/Join Synchronization Stations, Heedong Kim, Sarah M. Ryan Jan 2002

A New Analytical Evaluation Model For Kanban Controlled Systems With Fork/Join Synchronization Stations, Heedong Kim, Sarah M. Ryan

Industrial and Manufacturing Systems Engineering Conference Proceedings and Posters

A nonlinear programming model is developed for analyzing the queuing model of a kanban controlled system with fork/join synchronization stations. The model finds the minimum number of kanbans for a given throughput requirement or the maximum throughput for a given number of kanbans, where servers have different exponential service times. Furthermore, it aids understanding of kanban systems.


Discrete Real Options Models For Inter-Related Generation Projects, K. Jo Min, Chung-Hsiao Wang Jan 2002

Discrete Real Options Models For Inter-Related Generation Projects, K. Jo Min, Chung-Hsiao Wang

Industrial and Manufacturing Systems Engineering Conference Proceedings and Posters

The electric power generation business is facing uncertain and competitive environments with much financial risk. In this paper, we design and analyze a real options model for a utility with multiple inter-related generation planning projects. Also, comparisons relative to other models are made and a numerical example is provided so as to illustrate the optimal sequential decision making.


The Impact Of Surface Errors On The Location And Orientation Of A Cylindrical Workpiece In A Fixture, Supapan Sangnui, Frank E. Peters May 2001

The Impact Of Surface Errors On The Location And Orientation Of A Cylindrical Workpiece In A Fixture, Supapan Sangnui, Frank E. Peters

Industrial and Manufacturing Systems Engineering Publications

Surface error at the contact region is one factor that contributes to the displacement of the workpiece in a fixture. This work employs the Newton-Raphson technique to develop a mathematical model that predicts the impact of surface errors on the location and orientation of a cylindrical workpiece. Model validation and measurement analysis were conducted to verify the proposed mathematical model. An experimental fixture and workpiece were developed to simulate the effect of surface errors on the placement of a workpiece. The study showed that the numerical model is reliable in predicting the behavior of the workpiece.


Option Pricing Methods For Estimating Capacity Shortages, Dohyun Pak, Sarah M. Ryan Jan 2001

Option Pricing Methods For Estimating Capacity Shortages, Dohyun Pak, Sarah M. Ryan

Industrial and Manufacturing Systems Engineering Conference Proceedings and Posters

Uncertain demand combined with a positive lead time for adding capacity creates the risk of capacity shortage during the lead time. Accurate shortage estimation is very important to determine a capacity expansion policy. In this paper, we investigate four kinds of option pricing methods to estimate the shortage during a fixed lead time under the assumption of an exponential trend for demand growth. We compare the effect of the different shortage measures on the optimal parameters for an expansion policy over the long term.


A Simplified Procedure For Estimating Labor-Hour Requirements Of Discrete Assemblies, Deepak Srinivas, Kyung J. Min Jan 2000

A Simplified Procedure For Estimating Labor-Hour Requirements Of Discrete Assemblies, Deepak Srinivas, Kyung J. Min

Industrial and Manufacturing Systems Engineering Publications

Estimating the labor-hour requirements of discrete assemblies is often critical to numerous manufacturers because of its usefulness in determining the production cycle time, the costs of products, the performance of employees, and the price quotes to customers. The traditional method does not necessarily provide a fast and realistic estimation because of the time and complexity necessary to develop and estimate pre-specified times and allowances. In this paper. we propose a new procedure that is simpler and/aster. First, we present the data requirements and the regression-based procedure to estimate the Labor-hour requirements. Next, we show how specific linear and nonlinear ...


Determining Inventory Levels In A Conwip Controlled Job Shop, Sarah M. Ryan, Bruno Baynat, F. Fred Choobineh Jan 2000

Determining Inventory Levels In A Conwip Controlled Job Shop, Sarah M. Ryan, Bruno Baynat, F. Fred Choobineh

Industrial and Manufacturing Systems Engineering Publications

We extend the concept of CONWIP control to a job shop setting, in which multiple products with distinct routings compete for the same set of resources. The problem is to determine the fixed overall WIP level and its allocation to product types (WIP mix) to meet a uniformly high customer service requirement for each product type. We formulate an optimization problem for an open queuing network model in which customer orders pull completed products from the system. Then, assuming heavy demand, we derive a throughput target for each product type in a closed queuing network and provide a simple heuristic ...


Form Error Estimation Using Spatial Statistics, Tai-Hung Yang, John K. Jackman Jan 2000

Form Error Estimation Using Spatial Statistics, Tai-Hung Yang, John K. Jackman

Industrial and Manufacturing Systems Engineering Publications

Form error estimation is an essential step in the assessment of product geometry created through one or more manufacturing processes. We present a new method using spatial statistics to estimate form error. Using large sets of uniform sample points measured from five common machined surfaces, we compare the form error estimates using individual points and fitted surfaces obtained through spatial statistical methods. The results show that spatial statistics can provide more accurate estimates of form error under certain conditions.


Dimensional Variability Of Aluminum Castings, W.C. Faustine, R.C. Voigt, Frank Peters Jan 1999

Dimensional Variability Of Aluminum Castings, W.C. Faustine, R.C. Voigt, Frank Peters

Industrial and Manufacturing Systems Engineering Publications

The dimensional capabilities of production aluminum castings are described. More than 480 production casting features have been evaluated for jobbing shop aluminum castings made in green sand and permanent molds. A comprehensive database of casting, feature and process descriptors has also been developed, so that the influence of these factors on casting dimensional variability can be evaluated.

Measurement system analysis techniques have been used to ensure that the dimensional variability measured was not influenced by excessive measurement system errors. The dimensional variability of both green sand and permanent-mold castings is less than is suggested by International Standards Organization (ISO) casting ...


Effect Of Casting Form Variability On Machining Fixturing Error, Frank Peters, E.J. Salisbury Jan 1998

Effect Of Casting Form Variability On Machining Fixturing Error, Frank Peters, E.J. Salisbury

Industrial and Manufacturing Systems Engineering Publications

Many castings are eventually machined to create additional /ea/I/res or tighter tolerances that are beyond the capabilities of the casting process. To accomplish this machining, the castings must be /neared in a fix/ti re. Surface errors on the casting will cause the position and orientation of the casting to be offset from the nominal. This could result in problems, since the cutting roof is often programmed with respect to the fixture.


Dimensional Variability Of Production Iron Castings, E.S. Nazareth, R.C. Voigt, Frank Peters Jan 1998

Dimensional Variability Of Production Iron Castings, E.S. Nazareth, R.C. Voigt, Frank Peters

Industrial and Manufacturing Systems Engineering Publications

The dimensional variability of casting features from production gray and ductile iron castings has been characterized. Dimensional data from castings and patterns has been collected from castings produced at several jobbing foundries. The variability of over 300 casting features from castings produced in green sand molds using jolt squeeze, high-pressure horizontal parting line and vertical parting line molding processes have been evaluated


A Probabilistic View Of Problems In Form Error Estimation, Tai-Hung Yang, John K. Jackman Jan 1997

A Probabilistic View Of Problems In Form Error Estimation, Tai-Hung Yang, John K. Jackman

Industrial and Manufacturing Systems Engineering Publications

Form error estimation techniques based on discrete point measurements can lead to significant errors in form tolerance evaluation. By modeling surface profiles as random variables, we show how sample size and fitting techniques affect form error estimation. Depending on the surface characteristics, typical sampling techniques can result in estimation errors of as much as 50 percent. Another issue raised in the fitting approach is the metric p selection for the fitting objective. We show that for p = 2 and p = ∞, the selection does not appear to significantly affect the estimation of form errors


Haccp As A Regulatory Innovation To Improve Food Safety In The Meat Industry, Laurian J. Unnevehr, Helen H. Jensen Feb 1996

Haccp As A Regulatory Innovation To Improve Food Safety In The Meat Industry, Laurian J. Unnevehr, Helen H. Jensen

CARD Working Papers

Industrial engineers in the food-processing industry have developed the Halyard Analysis Critical Control Point (HACCP) system as a preventive approach to ensuring the safety of meat and poultry products. This paper discusses both the origins of HACCP as an engineering concept and the economics of HACCP as a regulatory tool. The authors contend that the economics literature has not adequately explored the benefits from prevention, particularly when the costs of hazard detection are high and the exact benefits of a particular standard are uncertain but potentially large.


Ice Skate Blade Alignment Mechanism, Leon E. Girard, Patrick E. Patterson Aug 1992

Ice Skate Blade Alignment Mechanism, Leon E. Girard, Patrick E. Patterson

Iowa State University Patents

A blade alignment mechanism for an ice skate including a clamp for releasably securing the blade assembly to a skating boot in a trial position. The clamp includes a first member secured to the boot at a point remote from the screw apertures in the front or rear flanges, and a second member attached to the first member and disposed to contact one of the flanges to hold it in a trial position. The second member includes an enlarged adjustment opening that allows side-to-side and fore-and-aft adjustment of the second member with respect to the first member. The first and ...