America's Space Exploration program is characterized by cutting edge technology in support of NASA's goals and research objectives. One principal component of the Space Shuttle System is the Orbiter Vehicle wh...
America's Space Exploration program is characterized by cutting edge technology in support of NASA's goals and research objectives. One principal component of the Space Shuttle System is the Orbiter Vehicle which undergoes necessary repairs and refurbishment at the Kennedy Space Center following each mission. The Orbiter's Thermal Protection System (TPS) is a mission critical component which protects the orbiter from the heat of re-entry from space. The University of Central Florida (UCF) research team was tasked with evaluating TPS processing requirements to reduce overall cycle times between operational missions. A job/task performance analysis was conducted to identify candidate TPS processes for evaluation and possible improvements. The research team developed a computer generated Improvement Potential Index (IPI) following a systematic data collection process. The IPI was then used to identify the top twenty processes which TPS engineers, quality assurance personnel and technicians identified as tasks which would most likely benefit from process improvement. The specified tasks were then analyzed for methods optimization. This paper documents the results of this effort to date, with emphasis on the Improvement Potential Index.
Presents a massively parallel machine for image processing and computer vision, designed to improve the AMP (Autonomous Multiprocessor), a previously designed pure-dataflow-based multiprocessor system for image proces...
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For the past 25 years of defense system acquisitions, the business side of government programs has controlled the underlying structure of the product-oriented work breakdown structure (WBS). As such, little interest h...
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Although technical reviews are an important part of the systemsengineering process, they have not received a great deal of attention in systemsengineering literature. In this paper, technical reviews are discussed f...
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Presents a massively parallel machine for image processing and computer vision, designed to improve the AMP (Autonomous Multiprocessor), a previously designed pure-dataflow-based multiprocessor system for image proces...
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Presents a massively parallel machine for image processing and computer vision, designed to improve the AMP (Autonomous Multiprocessor), a previously designed pure-dataflow-based multiprocessor system for image processing, and to make it faster and more efficient for image processing and computer vision tasks. In the basic design of the AMP there was room for improvement, and, therefore, the authors have recently begun to redesign an improved version of the AMP. The key point of the improvement is to increase the efficiency of execution, especially by optimizing its token matching mechanism, which is indispensable for dataflow-based processors, and the flexibility in its resource management mechanism. The authors first discuss the defects of the previous image processors, then give an overview of the original AMP design. The methodology of its optimization, and the improved system design are presented.< >
作者：
OSTENDORF, DWMOYER, EEXIE, YFRAJAN, RVDavid W. Ostendorf (Civil Engineering Department
University of Massachusetts Amherst MA 01003) is an associate professor in the Environmental Engineering Program of the Civil Engineering Department of the University of Massachusetts at Amherst. His research interests include unconfined aquifer contamination hazardous waste site remediation and analytical modeling of problems in environmental fluid mechanics. Ostendorf is a Registered Professional Engineer in Massachusetts and a member of the American Geophysical Union American Society of Civil Engineers Soil Science Society of America Water Pollution Control Federation and Association of Environmental Engineering Professors as well as the National Ground Water Association. Ellen E. Moyer (Civil Engineering Department
University of Massachusetts Amherst MA 01003) is a doctoral candidate in the Environmental Engineering Program of the Civil Engineering Department of the University of Massachusetts at Amherst with an M.S. degree in environmental engineering from that institution. Her research interests include subsurface investigation soil venting bioremediation and analytical modeling of subsurface contamination. She has six years of professional experience managing hazardous waste site investigation and cleanup projects and is a member of the National Ground Water Association and the American Society of Civil Engineers. Yuefeng Xie (Civil Engineering Department
University of Massachusetts Amherst MA 01003) is a postdoctoral research associate in the Environmental Engineering Program of the Civil Engineering Department of the University of Massachusetts at Amherst. His research interests include environmental analyses drinking water treatment and the chemical characterization and removal of disinfection by-products. A graduate with a Ph.D. and an M.S. in environmental engineering and a B.S. in chemistry and chemical engineeering from Tsinghua University Beijing China Xie is a member of the American Water Works Association and the Water Poll
The diffusion of 2,2,4-trimethylpentane (TMP) and 2,2,5-trimethylhexane (TMH) vapors out of residually contaminated sandy soil from the U.S. Environmental Protection Agency (EPA) field research site at Traverse City, ...
The diffusion of 2,2,4-trimethylpentane (TMP) and 2,2,5-trimethylhexane (TMH) vapors out of residually contaminated sandy soil from the U.S. Environmental Protection Agency (EPA) field research site at Traverse City, Michigan, was measured and modeled. The headspace of an intact core sleeve sample was swept with nitrogen gas to simulate the diffusive release of hydrocarbon vapors from residual aviation gasoline in and immediately above the capillary fringe to a soil-venting air flow in the unsaturated zone. The resulting steady-state profile was modeled using existing diffusivity and air porosity estimates in a balance of diffusive flux and a first order source term. The source strength, which was calibrated with the observed flux of 2,2,4-TMP leaving the sleeve, varied with the residual gasoline remaining in the core, but was independent of the headspace sweep flow rate. This finding suggested that lower soil-venting air flow rates were in principle as effective as higher air flow rates in venting LNAPL vapors from contaminated soils. The saturated vapor concentration ratio of 2,2,4-TMP to 2,2,5-TMH decreased from 6.6 to 3.5 over the duration of the experiments in an expression of distillation effects. The vertical profile model was tested against sample port data in four separate experiments for both species, yielding mean errors ranging from 0 to -24 percent in magnitude.
The University of Stellenbosch is currently developing a Low Earth Orbit (LEO) micro satellite for communication and mapping purposes. Since this will be the first South African developed experimental satellite, the p...
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The University of Stellenbosch is currently developing a Low Earth Orbit (LEO) micro satellite for communication and mapping purposes. Since this will be the first South African developed experimental satellite, the project will also be used to gain new technology for future aerospace and satellite applications. This project is financially supported by a number of South African companies. This paper discusses the power system requirements and proposes solutions for the power system design on board the satellite. The paper includes the simulation and analysis of the power system requirements of the orbiting satellite. Power electronic converters to be used will include maximum power point tracking, battery regulation, bus regulation and distributed power conversion. The specification and designs of key components, i.e. the solar panels, battery and regulators are evaluated against the system requirements during a typical flight path. These simulations include all the different modes of operation of the power system in an orbit cycle.
In situ air sparging (IAS) is becoming a widely used technology for remediating sites contaminated by volatile organic materials such as petroleum hydrocarbons. Published data indicate that the injection of air into s...
In situ air sparging (IAS) is becoming a widely used technology for remediating sites contaminated by volatile organic materials such as petroleum hydrocarbons. Published data indicate that the injection of air into subsurface water saturated areas coupled with soil vapor extraction (SVE) can increase removal rates in comparison to SVE alone for cases where hydrocarbons are distributed within the water saturated zone. However, the technology is still in its infancy and has not been subject to adequate research, nor have adequate monitoring methods been employed or even developed. Consequently, most IAS applications are, designed, operated, and monitored based upon the experience of the individual practitioner. The use of in situ air sparging poses risks not generally associated with most practiced remedial technologies: air injection can enhance the undesirable off-site migration of vapors and ground water contamination plumes. Migration of previously immobile liquid hydrocarbons con also be induced. Thus, them is an added incentive to fully understand this technology prior to application. This overview of the current state of the practice of air sparging is a review of available published literature, consultation with practitioners, a range of unpublished data reports, as well as theoretical considerations. Potential strengths and weaknesses of the technology are discussed and recommendations for future investigations given.
New models of conventional and single-wafer, cluster-based fabs running 0.35 micron logic flows have been developed based almost entirely on existing equipment technology. The cluster-based fabs are an embodiment of a...
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New models of conventional and single-wafer, cluster-based fabs running 0.35 micron logic flows have been developed based almost entirely on existing equipment technology. The cluster-based fabs are an embodiment of an alternative approach to semiconductor manufacturing, which is referred to as adaptable manufacturing systems (ASMs). Relative to conventional fabs, AMSs seek to balance throughput time and cost requirements, rather than only focusing on cost reduction as the dominant objective. The models are used to contrast the major components of throughput time and cost in the different types of fabs. Next, the models are used to show that that the optimal fab configurations and management strategies of the AMSs change over the life cycle of the fab. Making these changes at key points in the fab's life cycle allow the AMS to be more responsive to changing market demands, compared to conventional fabs.< >
Accidents in complex systems seldom arise from a single source, and are most often the result of multiple factors occurring at different levels of the system. Understanding the “systems” aspects of human performance...
Accidents in complex systems seldom arise from a single source, and are most often the result of multiple factors occurring at different levels of the system. Understanding the “systems” aspects of human performance (and performance error) in complex systems is a necessary part of any effort to avoid serious mishaps due to human error. This panel is intended to coincide with the development of a major research effort at the University of Wisconsin to address these issues. The Center for Human Performance in Complex systems will apply the disciplines of systemsengineering and ergonomics design to improve complex systems processes from the perspective of human performance. The purpose of this panel is to foster and demonstrate the Center's interest in bringing together a variety of perspectives and expertise bases to improve the overall quality and breadth of its activities. Each of the participants has a longstanding interest in improving the quality of human performance in complex and critical systems environments. Although they cannot represent the entire spectrum of relevant disciplines and perspectives of ergonomics and systems analysis, they provide a balance of insights, experience, and enthusiasm. This balance is essential to improving our understanding of factors affecting complex socio-technical systems, and implementing strategies to prevent and ameliorate the effects of system degradation and breakdown.
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