Institute for Systems Research Technical Reports

Permanent URI for this collectionhttp://hdl.handle.net/1903/4376

This archive contains a collection of reports generated by the faculty and students of the Institute for Systems Research (ISR), a permanent, interdisciplinary research unit in the A. James Clark School of Engineering at the University of Maryland. ISR-based projects are conducted through partnerships with industry and government, bringing together faculty and students from multiple academic departments and colleges across the university.

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Author: search.filters.author.Herrmann, Jeffrey W.Subject: search.filters.subject.Next-Generation Product Realization Systems

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    Designing a Decision-Making System for Exceptional Events: the Case of Medical Disaster Mutual Aid
    (2007) Herrmann, Jeffrey W.; Kothari, Alpa; Shaikh, Sana; Herrmann, Jeffrey W.; ISR
    Service enterprise engineering often involves designing systems that perform routine decision-making, as in business processes. However, exceptional events, which require effective decision-making to coordinate the response, are not routine. This paper presents a systematic, scenario-based methodology for designing such a decision-making system. The approach is based on the operational procedure methodology that has been used for developing avionics systems. The paper discusses an application to the case of medical disaster mutual aid, in which multiple hospitals must coordinate activities to respond to a mass casualty incident.
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    Constructing Queueing Network Approximations for Mass Dispensing and Vaccination Clinics
    (2006) Pilehvar, Ali; Herrmann, Jeffrey W.; Herrmann, Jeffrey W.; ISR
    This paper presents approximations for open queueing network models used to estimate the performance of mass dispensing and vaccination clinics. The approximations include the wait-in-batch-time, the departure variability at self-service stations, and the arrival variability for process batches.
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    Selecting an Optimization Model for Product Development
    (2006) Brochtrup, Brad M.; Herrmann, Jeffrey W.; Herrmann, Jeffrey W.; ISR
    Design optimization is an important engineering design activity. When used during the development of a new product, the overall profitability of that product depends upon the quality of the solution that the optimization model returns as well as the time and cost of using optimization. There exist many different ways to use optimization. The design engineer wants to select the most appropriate optimization model to create a profitable design. This paper discusses this meta-design (or meta-reasoning) problem and presents a method for selecting the best (most profitable) optimization model from a set of candidate optimization models. The approach allows multiple ways to handle uncertainty about the optimization models. We demonstrate the approach by considering the optimization of a universal electric motor.
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    Comparing Queueing Software for Mass Dispensing and Vaccination Clinics
    (2005) Treadwell, Mark; Herrmann, Jeffrey W.; Herrmann, Jeffrey W.; ISR
    Simulation models have been developed for use in evaluating the performance of mass vaccination clinics; spreadsheet forms of these models have also been produced for the benefit of end-users without access to simulation software. The same clinics are modeled in several queueing software packages, and the performance of the models is compared.
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    Controlling Iteration in Product Development Processes
    (2005) Herrmann, Jeffrey W.; Herrmann, Jeffrey W.; ISR
    Iteration is a dominant though unwelcome feature of product development. Controlling this iteration can reduce the time needed to complete product development projects. Management must decide how long each project should spend in a design stage before it undergoes a design review (or test). This paper presents a model of iteration that can be used to make this decision. The paper considers the single-project case and two scenarios in which multiple projects require a common reviewer. These results give some insight into how managers should control iteration to improve their product development processes.
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    Decomposition in Product Development
    (2004) Herrmann, Jeffrey W.; ISR
    Product development organizations seek to create profitable product designs. This paper discusses how the decomposition of the profit maximization problem leads to traditional product development processes. Decomposition provides a framework that integrates the conceptual models of decision-based design and the traditional description of product development processes. This paper identifies the key reasons for decomposition and discusses why the decomposition varies among product development organizations.
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    Selecting Equipment for Flexible Flow Shops
    (2003) Kumar, Rohit; Herrmann, Jeffrey W.; ISR
    Equipment selection is one of the challenges faced during manufacturing system design. Selecting the proper equipment is important to satisfying budget constraints, achieving required throughput, and reducing manufacturing cycle time and inventory. This paper formulates an equipment selection problem and presents two search algorithms used to find high-quality solutions. Queueing system models are used to calculate the manufacturing cycle time. The paper discusses the results of experiments conducted to evaluate the performance of the algorithms across a range of problem characteristics.
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    Rescheduling Frequency and Supply Chain Performance
    (2002) Herrmann, Jeffrey W.; Pundoor, Guruprasad; ISR
    Scheduling decisions control the flow of material and information in a supply chain. In many cases, scheduling decisions are made periodically. This paper studies how changes to the rescheduling frequency affect the performance of the participants of the supply chain. In the supply chains studied, the scheduling decisions and order release activities occur together. Three types of decisions are considered: ordering raw materials, scheduling production orders, and scheduling deliveries. Experimental results from two supply chains show that order release frequency affects the system performance more significantly than do the details of inventory and production control policies. Coordinating scheduling decisions between participants affects the performance of not only the individual participants but also the entire supply chain.
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    Viewing Product Development as a Decision Production System
    (2002) Herrmann, Jeffrey W.; Schmidt, Linda C.; ISR
    Product development includes many different types of decision-making by engineers and managers. Design decisions determine the product form and specify the manufacturing processes to be used. Development decisions, however, control the progress of the development process by defining which activities should happen, their sequence, and who should perform them.

    This paper introduces the concept of a decision production system to describe a product development organization as a system of decision-makers who use and create information to develop a product. This perspective does not advocate any particular type of product development process. Instead, it looks at the organization in which the product development process exists and considers the decision-makers as a manufacturing system that can be viewed separately from the organization structure.A new perspective is needed to reconcile product development practice and design theory.

    This paper argues that viewing product development as a decision production system provides a perspective to understand the costs and benefits associated with different forms of product development processes. The paper describes some of the benefits that this perspective and decision production system models would bring to product development organizations and to the design research community. Comprehensive models are needed to improve communication about the nature of product development and to understand the impact that changing product development processes will have on the organization's overall performance and profitability.

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    Sequencing Wafer Handler Moves to Improve the Performance of Sequential Cluster Tools
    (2000) Herrmann, Jeffrey W.; Nguyen, Manh-Quan T.; ISR
    Cluster tools are highly integrated machines that can perform a sequence of semiconductor manufacturing processes. The sequence of wafer handler moves affects the total time needed to process a set of wafers. Reducing this time can reduce cycle time, reduce tool utilization, and increase tool capacity. This paper introduces the cluster tool scheduling problem for sequential cluster tools and describes a branch-and-bound algorithm that can find an optimal sequence of wafer handler moves. In addition, we enumerate the set of 1-unit cyclic sequences for two- and three-stage sequential cluster tools. Experimental results show that the tool performance can be improved significantly if the wafer handler follows a cyclic sequence instead of using a dispatching rule.