Most of the brand new items are released on the market with a certain type of warranty. A fixed length warranty period is assumed in this paper. A set of maintenance policies which consist of minimal repair and preven...
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We present a technique for analyzing a simulation metamodel that has been constructed using a variance-stabilizing transformation. To compute a valid confidence interval for the expected value of the original simulati...
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We present a technique for analyzing a simulation metamodel that has been constructed using a variance-stabilizing transformation. To compute a valid confidence interval for the expected value of the original simulation response at a selected factor-level combination (design point), we first compute the corresponding confidence interval for the transformed response at that factor-level combination and then untransform the endpoints of the resulting confidence interval. Taking the midpoint of the untransformed confidence interval as our point estimator of the expected simulation response at the selected factor-level combination and approximating the variance of this point estimator via the delta method, we formulate an approximate two-sample student t-test for validating our metamodel-based estimator versus the results of making independent runs of the simulation at the selected factor-level combination. We illustrate this technique in a case study involving the design of a manufacturing cell, and we compare our results with those of a more conventional approach to analyzing transformed-based simulation metamodels. A Monte Carlo performance evaluation shows that significantly better confidence-interval coverage is maintained with the proposed procedure over a wide range of values for the residual variance of the transformed metamodel.
The U.S. Navy recently conducted an analysis of alternatives (AOA) to set the stage for determining the characteristics and acquisition strategy for its next generation aircraft carrier. The platform design selected i...
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The U.S. Navy recently conducted an analysis of alternatives (AOA) to set the stage for determining the characteristics and acquisition strategy for its next generation aircraft carrier. The platform design selected is expected to be in service throughout the 21st century. The parameters under consideration for change in the new carrier design lie in the areas of propulsion and electric power generation, aviation, survivability, service life, and total ownership cost (TOC) reduction. The issue of affordability is paramount This paper focuses on the need for the program management office and its supporting cost analysis staff to understand the life cycle cost (LCC) of the existing and proposed future aircraft carriers and to then translate these LCC's into meaningful information for cost-conscious decision making. The challenge is to relate the LCC in terms the key decision-makers and the engineering team can use to satisfy their respective roles. Thus, it is necessary to translate the results of the given ship design alternative LCC's into the paradigms of the respective stakeholders: Fleet User (operators of aircraft carriers) Ship Designers (translators of the fleet operator requirements) program Sponsors (providers of the funding resources) program Management Office, Ship builder and Supporting Industry (executors of the acquisition and construction of the ship) Navy and OSD decision-makers (overseers of program execution) The paper describes the aircraft carrier LCC breakdown structure that has resulted, in part, from a recent navy/shipbuilder integrated product team effort to capture total ownership costs. The structure has been used in the AOA as a tool to identify cost drivers and to add the time element to the cast equation in order to perform return on investment and program affordability analysis. The expanded ship work breakdown structure (ESWBS) has emerged as the central backbone of the cost work breakdown for AOA work. The ESWBS structure is a natural
An easily implemented approach to fuzzy system identification is proposed. The proposed approach consists of two phases. The first phase involves a baseline design to effectively identify a prototype fuzzy system for ...
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An easily implemented approach to fuzzy system identification is proposed. The proposed approach consists of two phases. The first phase involves a baseline design to effectively identify a prototype fuzzy system for a target system from a collection of input-output data pairs. This is implemented by incorporating the subtractive clustering method to determine the number of clusters and the fuzzy c-means (FCM) clustering algorithm to build the actual clusters. If the resulting prototype fuzzy system cannot describe the target system appropriately with respect to the input-output data pairs, the second-phase fine-tuning process to adjust the parameters identified in the baseline design is necessary. This process can be realized by using the steepest descent and recursive least-squares estimation methods. The proposed approach is validated by applying it to a function approximation type of problem: the truck backer-upper problem with an obstacle in the center of the field. For further confirmation, the learning behaviour of the proposed approach for this problem is studied.
作者：
Kopack, DSmith, GKim, DErne, DLDavid F. Kopack:is a Program Manager in the Naval Sea Systems Command
Office of Environmenta1 Protection Occupational Safety and Health SEA 00T. Mr. Kopack received his bachelor and master of science degrees in the physical sciences and management from the University of Maryland. Mr. Kopack has 20 years of experience in ship design and engineering industrial facility operations and program management. Gordon D. Smith:is a Chemical Engineer with the Carderock Division Naval Surface Warfare Center in Bethesda
Maryland and is working in the Naval Sea Systems Command Environmental and Auxiliary Systems Group. SEA 03L. Mr. Smith received his bachelor of science degree in chemical engineering from The Ohio State University. He has over 13 years of ronmental issues. In addition to supporting the development of Uniform National Discharge Standards he has been involved in research design testing and development of pollution abatement technologies suitable for use aboard Navy Ships. Don K. Kim:is a Senior Mechanical Engineer with the naval architecture and marine engineering firm of M. Rosenblatt & Son
Inc. in Arlington Virginia. Mr. Kim received his bachelor of science and master of engineering degrees in mechanical engineering from the University of Virginia. He is a registered Professional Engineer in the Commonwealth of Virgina. Mr. Kim has ten years of experience in the design installation maintenance and repair of shipboard mechanical systems equipment and components with specific expertise in compressor pump and fan design and operation. He is a member of the American Society of Naval Engineers and the American Society of Mechanical Engineer. David L. Erne:is an Associate with Booz Allen and Hamilton
Inc. in Arlington Virginia. Mr. Erne received his bachelor of science degree in chemical engineering from the University of Idaho. He has over twelve years of experience in environmental program management and consulting. In addition to his support for the Uniform National Discharge Standards prog
In the Fiscal Year 1996 National Defense Authorization Act, Congress amended the Clean Water Act to provide the Department of Defense and the Environmental Protection Agency authority to jointly establish standards fo...
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In the Fiscal Year 1996 National Defense Authorization Act, Congress amended the Clean Water Act to provide the Department of Defense and the Environmental Protection Agency authority to jointly establish standards for incidental discharges from Armed Forces' vessels. The uniform national standards would apply to discharges from vessels of the Navy, Military Sealift Command, Army, Marine Corps, Air Force, and Coast Guard to the navigable waters and contiguous zone of the U.S. and its territories. Uniform National Discharge Standards (UNDS) will require control of discharges, by either a technology or management practice. UNDS will facilitate the Armed Forces' ability to better design and build future vessels to be environmentally sound and to maintain the operational flexibility of Armed Forces' vessels both domestically and internationally. The development of standards for Armed Forces' vessel discharges may have greater impact on naval engineering requirements for future vessels than any other single environmental issue, These standards are expected to stimulate the development of innovative vessel pollution control technologies, which on be used for both Armed Forces' vessels and commercial shipping vessels. This paper provides an overview of UNDS development, summarizes the results of UNDS Phase I, provides a summary overview of the preliminary approach for accomplishing UNDS Phase Il, and discusses implications for future naval engineering efforts.
作者：
Markle, SPGill, SEMcGraw, PSUdr. Stephen P. Markle
USN is a career Engineering Duty officer assigned to Naval Sea Systems Command Arlington Virginia where he is Deputy Directs Environmental Programs Division (SEA 03L1 B). He is responsible fm program management activities associated with all ahat environmental protection equipment design and selection of environmental protection equipment and systems fm future surface ship designs (DD 21 CVN 7Z CW LPD 17) and serves on several teams designed to promote Nay wide awarmss of environmental protection requirements and Nay programs to meet these challenges. He is a 1993 graduate of the Naval Construction and Engineering Program at the Massachusetts Institute of Technology where he received a naval engineers degree and master of science in mechanical engineering. His interest in environmental issues predates his undergraduate studies at Syracuse Universityl State University of New Ymk College of Environmental Science and Fmestry where he received a bachelm of science degree in fmest engineering from the School of Environmental and Resource Engineering. LCdx Markle has qualified as a Surface Warfare Officer and in submarines through the Engineering Duty Dolphin Program he is a member of the Acquisition Professional Community and a graduate of the Defense Systems Management College Advanced Program Managers Course. He is a professional engineer registered in the State of New York and is a member ofthe American Society of Naval Engineers National Society of Professional Engineers American Society for Testing and Materials Society of Naval Architects and Marine Engineers and Society of Automotive Engineers. Peter 5. McGraw is current the Acting Branch Head ofthe Solid Waste Management Branch (Code 634) of the Environmental Quality Dwrtment of the Naval Surfice Warfare Centel: Carderock Division. As such
he is responsible for among other things: the Shipboard Advanced Incinerator RDT&E Program the Submarine Plastic Waste RDT&E Program Solid Waste Processing Equipment Design Acquisitio
The past twenty-five years has been marked by the introduction ed marine environmental regulations that have had a profound effect on how ships are designed, built and operated. Ships being designed and built today mu...
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The past twenty-five years has been marked by the introduction ed marine environmental regulations that have had a profound effect on how ships are designed, built and operated. Ships being designed and built today must accommodate not only current regulations but anticipate those enacted over their thirty to fifty year life cycles. U.S. Chief of Naval Operations, Office of Environmental, Safety and Health (CNO N45) has articulated a vision for the Environmentally Sound Warship of the Twenty-first Century. This vision incorporates the "Sense of Congress" for a naval ship designed to operate in full compliance with environmental regulations worldwide. The task of the Navy engineering team is to translate this vision into reality;a ship capable of prevailing in time of war and able to conduct operations in all areas of the globe, unencumbered by special procedures for environmental compliance. The keys to this warship design are the early integration of environmentally sound principles, materials, and processes into the ship acquisition process;minimization of both hazardous materials and generation of post shipboard consumer waste during operation;adaptation of integrated systems to reduce the volume of wastes and enhance processing efficiency;reduced manpower requirements;and crew indoctrination in environmental protection.
Impedance control allows the manipulator to change the mechanical impedance such as inertia, damping and stiffness, acting between the end-effector and its environment. However, to achieve stable force control under u...
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Impedance control allows the manipulator to change the mechanical impedance such as inertia, damping and stiffness, acting between the end-effector and its environment. However, to achieve stable force control under unknown stiff environments, complicated tuning of desired impedance parameters is needed. Among the parameters, the desired damping is the most significant to suppress overshoots and oscillations. In the paper generalized fuzzy environment models with anisotropy are proposed to systematically determine the desired damping against unknown environments. The models learned with genetic algorithms, can estimate each directional stiffness of the environment and yield the desired damping, considering the critical damping condition of the control system. Position and force control simulations are shown to demonstrate the effectiveness and promise of the models.
A position based impedance control with a fuzzy compensator is proposed to improve a force control performance, in which the environment has unknown dynamics or curved surface. The main attraction of the fuzzy compens...
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A position based impedance control with a fuzzy compensator is proposed to improve a force control performance, in which the environment has unknown dynamics or curved surface. The main attraction of the fuzzy compensator is that it generates proper position compensation as feedforward command so that overshoots and oscillations in the direction of force control can be suppressed satisfactorily. Profiling control simulations using the dynamics of the PUMA560 manipulator are shown to demonstrate the effectiveness and promise of the fuzzy compensator under the environment having unknown dynamic characteristics.
Bayesian forecasting models provide distributional estimates for random parameters, and relative to classical schemes, have the advantage that they can rapidly capture changes in nonstationary systems using limited hi...
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Bayesian forecasting models provide distributional estimates for random parameters, and relative to classical schemes, have the advantage that they can rapidly capture changes in nonstationary systems using limited historical data. Stochastic programs, unlike deterministic optimization models, explicitly incorporate distributions for random parameters in the model formulation, and thus have the advantage that the resulting solutions more fully hedge against future contingencies. We exploit the strengths of Bayesian prediction and stochastic programming in a rolling-horizon approach that can be applied to solve real-world problems. We illustrate the methodology on an employee scheduling problem with uncertain up-times of manufacturing equipment and uncertain production rates.
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