85 research outputs found

    Production and inventory control in complex production systems using approximate dynamic programming.

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    Production systems focus not only on providing enough product to supply the market, but also on delivering the right product at the right price, while lowering the cost during the production process. The dynamics and uncertainties of modern production systems and the requirements of fast response often make its design and operation very complex. Thus, analytical models, such as those involving the use of dynamic programming, may fail to generate an optimal control policy for modern production systems. Modern production systems are often in possession of the features that allow them to produce various types of product through multiple working stations interacting with each other. The production process is usually divided into several stages, thus a number of intermediate components (WIP) are made to stock and wait to be handled by the next production stage. In particular, development of an efficient production and inventory control policy for such production systems is difficult, since the uncertain demand, system dynamics and large changeover times at the work stations cause significant problems. Also, due to the large state and action space, the controlling problems of modern production systems often suffer from the curse of dimensionality

    Space station System Engineering and Integration (SE and I). Volume 2: Study results

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    A summary of significant study results that are products of the Phase B conceptual design task are contained. Major elements are addressed. Study results applicable to each major element or area of design are summarized and included where appropriate. Areas addressed include: system engineering and integration; customer accommodations; test and program verification; product assurance; conceptual design; operations and planning; technical and management information system (TMIS); and advanced development

    Targeting Net Zero Energy at Marine Corps Air Station Miramar: Assessment and Recommendations

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    In 2008, the Department of Defense (DoD) and Department of Energy (DOE) defined a joint initiative to address military energy use by identifying specific actions to reduce energy demand and increase use of renewable energy on DoD installations. A Task Force comprised of representatives from the Office of the Secretary of Defense (OSD), the four military Services, DOE’s Federal Energy Management Program (FEMP), and the National Renewable Energy Laboratory (NREL) was established. In light of DoD priorities, early attention was given to the possibility of net zero energy military installations (NZEI), that is, installations that would meet their energy needs with local renewable resources. Marine Corps Air Station (MCAS) The Task Force selected Miramar to be the prototype installation for net zero energy assessment and planning. This selection was based on Miramar’s strong history of energy advocacy and extensive track record of successful energy projects

    The Evaluation of the Sustainability of a Modern Residential Dwelling in a Humid Subtropical Environment

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    The objective of this research is the life cycle analysis of a high-performance, above-code home as compared to a more traditionally built home in a humid, subtropical environment. Building energy estimations and environmental impacts analyses were performed, and model development and results were presented. Renewable energy and rainwater collection systems impacts were also investigated. Annual operational energy was reduced 30% due to decreases in the HVAC energy associated with infiltration and building envelope differences between the ‘Reference’ and ‘As-Built’ models. Gas-based heating models embodied energies were 6% and 12% of the total energy and the use phase energy was 93% and 87% for the ‘Reference’ and ‘As-Built’ models, respectively. The embodied energy in the ‘Reference’ model was almost half of the embodied energy in the ‘As-Built’, but the ‘As-Built’ model achieved a reduction of life cycle primary energy of 23% compared to the ‘Reference’ model. A reduction of 6,314 GJ and 402 metric tons of primary energy and GWP was achieved for the ‘Reference’ compared to the ‘As-Built’ model. Total primary energy over the life cycle was 26,216 and 19,983 GJ, with energy intensities of 44.4 and 33.8 GJ/m^2 for the ‘Reference’ and ‘As-Built’ models, respectively. The electrical-based heating models followed similar trends as the gas-based model but with a small increase in operational energy. Global warming potential had similar distribution patterns as that of the primary energy and total life cycle global warming potential intensities were estimated for the ‘Reference’ and ‘As-Built’ models, respectively as 2,835 and 2,166 kg CO2-eq/m^2. Solar electric and hot water renewable energy systems decreased the annual operating energy by 12.5% and 15.5% and the total life cycle primary energy by 9.4% and 13.4% for the ‘Reference’ and ‘As-Built’ models, respectively. Finally, with no rainwater harvesting, total water consumption was 29.68 and 31.78 mega-liters for the ‘Reference’ and ‘As-Built’. The use phase dominates both models with 85% and 80% of the use phase for the ‘Reference’ and ‘As-Built’ model, respectively. Rainwater harvesting systems may offset the life cycle use phase and with a Monte-Carlo simulation yielded a 73% demand reduction with a 48% probability

    Targeting Net Zero Energy at Marine Corps Air Station Miramar: Assessment and Recommendations

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    Proceedings of the 6th International Conference EEDAL'11 Energy Efficiency in Domestic Appliances and Lighting

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    This book contains the papers presented at the sixth international conference on Energy Efficiency in Domestic Appliances and Lighting. EEDAL'11 was organised in Copenhagen, Denmark in May 2011. This major international conference, which was previously been staged in Florence 1997, Naples 2000, Turin 2003, London 2006, Berlin 200h9a s been very successful in attracting an international community of stakeholders dealing with residential appliances, equipment, metering liagnhdti ng (including manufacturers, retailers, consumers, governments, international organisations aangde ncies, academia and experts) to discuss the progress achieved in technologies, behavioural aspects and poliacineds , the strategies that need to be implemented to further progress this important work. Potential readers who may benefit from this book include researchers, engineers, policymakers, and all those who can influence the design, selection, application, and operation of electrical appliances and lighting.JRC.F.7-Renewable Energ

    Trends in Wind Energy Technology Development

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    The role of biomass and CCS in China in a climate mitigation perspective

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    Long-term modelling of Carbon Capture and Storage, Nuclear Fusion, and large-scale District Heating

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