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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

AN EVENT-BASED APPROACH TO DEMAND-DRIVEN DYNAMIC RECONFIGURABLE COMPUTING

LEE, TAI-CHUN 11 October 2001 (has links)
No description available.
2

A Demand Driven Re-fleeting Approach for Aircraft Assignment Under Uncertainty

Zhu, Xiaomei 29 August 2001 (has links)
The current airline practice is to assign aircraft capacity to scheduled flights well in advance of departure. At such an early stage in this process, the high uncertainty of demand poses a major impediment for airlines to best match the airplane capacities with the final demand. However, the accuracy of the demand forecast improves markedly over time, and revisions to the initial fleet assignment become naturally pertinent when the observed demand considerably differs from the assigned aircraft capacity. The Demand Driven Re-fleeting (DDR) approach proposed in this thesis offers a dynamic re-assignment of aircraft capacity to the flight network, as and when improved demand forecasts become available, so as to maximize the total revenue. Because of the need to preserve the initial crew schedule, this re-assignment approach is limited within a single family of aircraft and to the flights assigned to this particular family. This restriction significantly reduces the problem size. As a result, it becomes computationally tractable to include path level demand information into the DDR model, although the problem size can then get very large because of the numerous combinations of composing paths from legs. As an extension, models considering path-class level differences, day-of-week demand variations, and re-capture effects are also presented. The DDR model for a single family with path level demand considerations is formulated as a mixed-integer programming problem. The model's polyhedral structure is studied to explore ways for tightening its representation and for deriving certain classes of valid inequalities. Various approaches for implementing such reformulation techniques are investigated and tested. The best of these procedures for solving large-scale challenging instances of the problem turns out to be an integrated approach that uses certain selected model augmentations and valid inequalities generated via a suitable separation routine and a partial convex hull construction process. Using this strategy in concert with properly selected CPLEX options reduces the CPU time by an average factor of 7.48 over an initial model for a test-bed of problems each having 200 flights in total. Prompted by this integrated heuristic approach, a procedure for finding solutions within a prescribed limit of optimality is suggested. To demonstrate the effectiveness of these developed methodologies, we also solved two large-scale practical-sized networks that respectively involve 800 and 1060 flights, and 18196 and 33105 paths in total, with 300 and 396 flights belonging to the designated family. These problems were typically solved within 6 hours on a SUN Ultra 1 Workstation having 260 MB RAM and a clock-speed of 167 MHz, with one exception that required 14 hours of CPU time. This level of computational effort is acceptable considering that such models are solved at a planning stage in the decision process. / Master of Science
3

Risk Analysis and Pricing of Retail Energy Contracts / Analýza rizik a oceňování energetických retailových kontraktů

Hron, Jiří January 2007 (has links)
The presented dissertation is focused on the applications of statistical methods and ap-proaches applied in the energy business. The need for the modeling of energy risks arose only recently when the energy business was opened to competition. Therefore, the prima-ry aim of the dissertation is to clarify the main principles of the energy business which are necessary for understanding both risk principles and motivation of the proposed models. I am largely focused on retail risks, i.e., the risks associated with delivery to end-consumers. In particular, I deal with energy contracts providing volume flexibility, recalled as swing options in the literature. Therefore, the second issue on which I am focusing is a group of demand-driven swing options whose more systematic analysis in the portfolio context has not been published so far. Examining the risk, I apply the deductive (probabil-istic) analysis which reveals interesting relations between correlations. The practical ap-plications also require inductive considerations resulting in the construction of statistical estimators relying on historical data. I propose an estimator of the volumetric correlation based on a classical theory whose bias is investigated via MC simulation. To analyze a par-ticular volume-price correlation, I introduced the notion of robust dependency. Applying bootstrap procedures, robust dependency can be used both for testing purposes and for sensitivity analysis of the sample correlation. There are many works available devoted to energy price models which are different from the price models applied on financial markets. Therefore, the third target of the dis-sertation is an empirical statistical analysis of both power and natural gas Czech spot pric-es which can serve as a basis for the development of price models adapted to the Czech market environment. Finally, the fourth aim is the evaluation of power contracts which is very specific. The outputs of the model are both a synthetic market price and a hedging strategy. The model is designed to provide flexibility in practical applications.
4

Optimization of Axial Piston Units Based on Demand-driven Relief of Tribological Contacts

Haug, Stefan, Geimer, Marcus 27 April 2016 (has links) (PDF)
Markets show a clear trend towards an ever more extensive electronic networking in mobile and stationary applications. This requires a certain degree of electronic integration of hydraulic components such as axial piston pumps. Beside some wellknow approaches, the transmission of axial piston units still is relatively unexplored regarding electronification. Nonetheless there is a quite high potential to be optimized by electronic. In view of this fact, the present paper deals with the tribological contacts of pumps based on a demand driven hydrostatic relief. The contact areas at cylinder - distributor plate, cradle bearing and slipper - swash plate will be investigated in detail and it will be shown how the pump behavior can be improved considerably through a higher level of relief and a central remaining force ratio. The potential of optimization is to improve the efficiency, especially in partial loaded operation, power range, also for multi quadrant operation, precision and stability. A stable lubricating film for slow-speed running and for very high speeds at different pressures is ensured as well.
5

Demand-Driven Static Analysis of Heap-Manipulating Programs

Chenguang Sun (5930306) 16 August 2019 (has links)
<div>Modern Java application frameworks present significant challenges for existing static analysis algorithms. Such challenges include large-scale code bases, heap-carried dependency, and asynchronous control flow caused by message passing.</div><div>Existing analysis algorithms are not suitable to deal with these challenges. One reason is that analyses are typically designed to operate homogeneously on the whole program. This leads to scalability problems when the analysis algorithms are used on applications built as plug-ins of large frameworks, since the framework code is analyzed together with the application code. Moreover, the asynchronous message passing of the actor model adopted by most modern frameworks leads to control flows which are not modeled by existing analyses.</div><div>This thesis presents several techniques for more powerful debugging and program understanding tools based on slicing. In general, slicing-based techniques aim to discover interesting properties of a large program by only reasoning about the relevant part of the program (typically a small amount of code) precisely, abstracting away the behavior of the rest of the program.</div><div>The key contribution of this thesis is a demand-driven framework to enable precise and scalable analyses on programs built on large frameworks. A slicing algorithm, which can handle heap-carried dependence, is used to identify the program elements relevant to an analysis query. We instantiated the framework to infer correlations between registration call sites and callback methods, and resolve asynchronous control flows caused by asynchronous message passing.</div>
6

Möjligheter med Supply Chain Management i produktionen av Active Pharmaceutical Ingredient : en utvärdering och empirisk fallstudie av Demand Driven Supply inom AstraZeneca AB

Gustafsson, Anders, Wenngren, Johanna January 2008 (has links)
<p>De stora läkemedelsbolagen har sedan mitten på 1990-talet fått en ökad press på att optimera sina försörjningskedjor på grund av att patent på olika mediciner gått ut. När patentet gått ut kan generiska konkurrenter börja sälja liknande mediciner, de kan sälja dem till lägre pris eftersom de inte har forsknings och utvecklingskostnader att täcka. AstraZeneca tog i slutet av 1990-talet beslutet att implementera en ny strategi för deras försörjningskedja i deras produktion. Detta gjordes för att sänka deras produktionskostnader för att kunna konkurrera mot generiska konkurrenter. En konsultfirma togs in och Demand Driven Supply (DDS) implementerades. Syftet med denna uppsats är att definiera Demand Driven Supply och att utvärdera om denna implementering gett de resultat som eftersträvades. Vi presenterar en teoretisk referensram som behövs för att få en förståelse över de metoder och verktyg som behövs för att optimera varuförsörjningskedjan och därigenom kunna sänka kostnaderna. Dessa teorier står till grund för den implementering som skedde hos AstraZeneca. Den huvudsakliga anledningen till att DDS implementerades var att AstraZeneca ville gå mot sugande produktionsstyrning för att därmed korta ledtiden, sänka kostnader och sänka kapitalbindningen och höja marginalerna på sin försäljning för att få kapital till att återinvestera i företaget.</p>
7

Demand Driven Disassembly Planning

Ertem, 01 January 2007 (has links) (PDF)
In this thesis, we deal with the demand driven disassembly planning. The main aim of the study is to construct heuristic approaches according to the suggested improvements in the literature. These heuristic approaches are further improved by recognizing the key points of the disassembly planning problem. All of the solution approaches aim minimizing total cost related to relevant costs of disassembly operations. Another subject given attention in this thesis is the importance of the setup cost on the disassembly planning, which has not been studied yet in the literature to the best of our knowledge. Computational studies are carried out to assess the performance of the heuristic procedures proposed.
8

Patron-Driven Acquisitions: Bridging the Boundaries of Need and Access to Information Resources

See, Andrew 06 1900 (has links)
Poster presented at ALA Annual Conference 2013, Chicago, IL / As the University of Arizona Libraries employ a 21st century user-centered approach to information resource management, we have adopted a Patron-Driven Acquisitions program. Fundamentally, the program is based on the model of users as the drivers of library acquisitions. By embedding order records in the library catalog and by identifying user needs through interlibrary loan requests, the library is able to acquire targeted information resources that more efficiently meet the research needs of our users. This service significantly enhances the user experience and allows the UA Libraries to see greater use of our resources.
9

Möjligheter med Supply Chain Management i produktionen av Active Pharmaceutical Ingredient : en utvärdering och empirisk fallstudie av Demand Driven Supply inom AstraZeneca AB

Gustafsson, Anders, Wenngren, Johanna January 2008 (has links)
De stora läkemedelsbolagen har sedan mitten på 1990-talet fått en ökad press på att optimera sina försörjningskedjor på grund av att patent på olika mediciner gått ut. När patentet gått ut kan generiska konkurrenter börja sälja liknande mediciner, de kan sälja dem till lägre pris eftersom de inte har forsknings och utvecklingskostnader att täcka. AstraZeneca tog i slutet av 1990-talet beslutet att implementera en ny strategi för deras försörjningskedja i deras produktion. Detta gjordes för att sänka deras produktionskostnader för att kunna konkurrera mot generiska konkurrenter. En konsultfirma togs in och Demand Driven Supply (DDS) implementerades. Syftet med denna uppsats är att definiera Demand Driven Supply och att utvärdera om denna implementering gett de resultat som eftersträvades. Vi presenterar en teoretisk referensram som behövs för att få en förståelse över de metoder och verktyg som behövs för att optimera varuförsörjningskedjan och därigenom kunna sänka kostnaderna. Dessa teorier står till grund för den implementering som skedde hos AstraZeneca. Den huvudsakliga anledningen till att DDS implementerades var att AstraZeneca ville gå mot sugande produktionsstyrning för att därmed korta ledtiden, sänka kostnader och sänka kapitalbindningen och höja marginalerna på sin försäljning för att få kapital till att återinvestera i företaget.
10

Towards a Statistical Physics of Collective Mobility and Demand-Driven Transport

Sorge, Andreas 19 June 2017 (has links)
No description available.

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