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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Item A Comparative Study of Reactor Designs for the Production of Graded Films with Applications to Combinatorial CVD(2007) Sreenivasan, Ramaswamy; Adomaitis, Raymond A.; Rubloff, Gary W.; ISRSegmented CVD reactor designs enabling spatial control of across-wafer gas phase composition were evaluated for depositing graded films suitable for combinatorial studies. Specifically two reactor designs were constructed and evaluated with experiments and response surface model (RSM) based analysis to quantify the reactor performance in terms of film thickness uniformity, sensitivity to adjustable reactor operating conditions, range of thickness over which uniformity could be achieved and each reactor ability to control the thickness gradient across the wafer surface. Design features distinguishing the two reactor systems and their influence on gradient control versus deposition rate performance are summarized. RS models relating wafer state properties to process recipes are shown to be effective tools to quantify, qualify and compare different reactor designs.Item 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.; ISRService 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.Item Applying VR Technology to Training in Manufacturing Processes(2006) Ledoux, Kathryn; Deshpande, Nikita; Gupta, S.K.; ISRThe use of Virtual Reality to enhance existing training methods is growing increasingly popular in fields such as medicine, emergency services, and flight instruction. It offers an effective training solution in terms of cost, time expenditure, quality of training offered. The Virtual Training Studio was created to offer tutorials on industrial and procedural assembly and disassembly operations, serving the manufacturing industry, whose turnover rate demands constant training for new employees. It currently supports a tutorial instructing users how to assemble a naval rocket. Users are placed in a virtual environment and their position is tracked by four cameras, as well as two gyroscopes, mounted on their HMD and wand controller. The parts of the rocket are positioned in the environment, and step-by-step text instructions are displayed on a projector screen in the room. Users can click buttons next to the projector to select different instruction options. Auto allows them to view an animated automatic assembly, Manual allows them to assemble the object independently using the instructions given on the screen, and Video allows them to view step-by-step video instructions.Item Constructing Queueing Network Approximations for Mass Dispensing and Vaccination Clinics(2006) Pilehvar, Ali; Herrmann, Jeffrey W.; Herrmann, Jeffrey W.; ISRThis 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.Item Selecting an Optimization Model for Product Development(2006) Brochtrup, Brad M.; Herrmann, Jeffrey W.; Herrmann, Jeffrey W.; ISRDesign 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.Item Hardware and Design Factors for the Implementation of Virtual Reality as a Training Tool(2006) Miranda, Walter; Gupta, S.K.; ISRThe overall goal of this project is to reduce the occurrences of motion sickness among the participants in virtual reality training systems. To do this, new rooms were designed in order to decrease the head motion of the user. In designing these rooms, two different modeling software packages were used and compared to determine which would be best for future use. Also, the room contains three entities that cause head motion: table, projector screen, and control panel. The goal in the design was to place these entities so that the user would minimize his head motion and as well as not obstruct the parts being assembles. Finally, suggestions were made for the hardware of the virtual environment so that the physical lag time could be decreased as much as possible.Item Virtual Reality Wand Design and Fabrication(2006) Oberc, Timothy J.; Gupta, S.K.; ISRAs virtual reality (VR) is becoming a more viable option for real world skills training, developers are attempting to uncover the methods and technologies that will lead to the most efficient transfer of knowledge and proficiency of the target tasks. Within these optimization issues lies the question that asks what type of VR interaction device will provide users with maximum control within the virtual environment (VE) while being a convenient and comfortable tool to use. An ideal interaction device should balance the factors of functionality, user satisfaction, and cost while yielding a well-designed product in the process. Although the needs for all VR systems are not the same, popular interaction devices in use today include wired gloves as well as VR wands, the current mode of interaction for study during this summer REU ISR project.Item Classifying and Comparing Design Optimization Problems(2006) Brochtrup, Brad M.; Herrmann, Jeffrey W.; ISRResearch in product design optimization has developed and demonstrated a variety of modeling techniques and solution methods, including multidisciplinary design optimization. As new techniques migrate to the industrial world engineers are faced with much more complex problems often extending beyond their realm of knowledge. A novel classification scheme is proposed and demonstrated to offer engineers a method of organizing and searching for relevant example problems to assist in the production of their own optimization problem. To explore the tradeoff between information requirements and solution quality, computational experiments are conducted on two design problems, a bathroom scale and a universal electric motor. In particular, the results of these experiments identify the additional information required to solve a profit maximization problem, demonstrate the role of rules of thumb in formulating design optimization problems, show how decomposition affects solution quality and computational effort, and uncover the impact of using target matching in the objective function instead of as constraints. In addition, the results show how the values of targets and objective function weights impact solution quality. In general, these results show the extent to which correct information is critical to finding a high quality solution, perhaps more critical than the optimization model selected. That is, the quality of the information used is more important than the amount of information used.Item Queueing Models and Assessment Tools for Improving Mass Dispensing and Vaccination Clinic Planning(2006) Treadwell, Mark; Herrmann, Dr. Jeffrey; ISRTo react to an outbreak of a contagious disease that requires medication or vaccination, county health departments must set up and operate mass dispensing and vaccination centers, commonly known as points of dispensing (PODs), to treat residents who may be affected. Carefully planning these PODs before an event occurs is a difficult and important job. Simulation models can provide an accurate representation of resident flow through PODs, but are not convenient for public health professionals to access. Queueing theory provides a multitude of analytical models appropriate for various situations so many models that it is often difficult to discern which model is correct for a particular circumstance. There are also some situations for which no models are available, particularly those involving batching and multiple servers. A complete set has been gathered of those models that are the most generalized, and hence useful for the widest range of applications. Where no appropriate model was available, modifications to the existing equations are proposed and tested. To implement this general queueing framework, software has been developed which can quickly generate planning models using steady-state queueing network approximations; these models use commonly available spreadsheet software to maximize accessibility for public health emergency planners. The planning models are validated against models created in several queueing software packages, along with simulation models automatically generated from the planning models. The number of stations and staff within a POD are not the only concerns that a public health emergency preparedness and response plan must address. A plan assessment tool is proposed, which can help planners ensure that their POD plans include all relevant information. A layout assessment tool is also developed, which endeavors to give planners suggestions on how to design PODs for maximum efficiency.Item Variability Driven Gate Sizing for Binning Yield Optimization(2006) Davoodi, Azadeh; Srivastava, Ankur; ISR