Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 18 of 18 for “"continuum approximation"”.
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Optimal patrol routing and scheduling for parking enforcement considering drivers' parking behavior
… programming model, and a continuous approximation model based on the method of continuum approximation. Numerical tests are performed in order to examine the performance of these two models using randomly-generated datasets. Sensitivity analyses show that as parking price or demand …
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Community detection on urban street networks : a segmentation model for urban logistics policy and planning
… transportation, especially in contexts where continuum approximation methods might be employed. The ratio of simulated trip distances over the actual road network to the idealized distance between the trip endpoints is used as a metric to quantify some travel properties of these segments.
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Analysis of ultra-narrow ferromagnetic domain walls
… potential stemming from the breakdown of the continuum approximation of matter is calculated and its contribution to the coercive force of hard materials is depicted. The interaction of a very narrow domain wall with a similarly narrow planar defect is analyzed. Time-dependent motion of such …
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Reliable facility location design and traffic sensor deployment under probabilistic disruptions
… large. To improve computational tractability, continuum approximation models (where customers and facilities are approximated by continuous spatial densities) are developed to approximate problems in a continuous metric space and provide good approximate solutions to large-scale instances. We …
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Effects of road-network circuity on strategic decisions in urban logistics
… urban infrastructure data to improve analytical approximation methods used to inform strategic decisions in designing last-mile distribution systems. In particular, this thesis explores the effects of the road-network on the circuity of local trips, and introduces data-driven extensions to …
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Fully-kinetic PIC simulations for Hall-effect thrusters
… operation. Originally, simulations assumed a continuum approximation for electrons and used magnetohydrodynamic fluid equations to model the significant processes. While these codes were computationally efficient, their applicability to non-equilibrated regions of the thruster, such as wall …
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Advances in fully-kinetic PIC simulations of near-vacuum Hall thruster and other plasma systems
… operation. Originally, simulations assumed a continuum approximation for electrons and used magnetohydrodynamic fluid equations to model the significant processes. While these codes were computationally efficient, their applicability to non-equilibrated regions of the thruster, such as wall …
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Data-Driven Bike-Share Ridership Prediction and Network Optimization
… support demand-responsive planning. Second, a continuum approximation model is proposed for station placement optimization, using a force-based algorithm that balances attraction from demand centers with inter-station forces. This ridership-driven approach departs from conventional …
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The phase transition of the rubidium halides
… can be adequately treated using the elastic continuum approximation. This approximation was able to approximately account for the variation in Debye temperature across the transition, the thermal energy and the entropy change at the transition. The procedure is also useful in predicting the …
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Transit network design for areas with low and/or heterogeneous demand
… a methodological framework is developed so that continuum approximation (CA) techniques can be used to design bus networks for cities where travel demand varies gradually over space. The bus-route configurations consist of (i) a main, city-wide grid with relatively large physical spacings between …
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Flexible transit network design with and without branching under spatially heterogeneous demand
… the optimal route layout and service operation, continuum approximation is used to reduce the computation burden and formulate the problem in terms of a few decision variables. Unlike many continuous models, passenger distribution is not assumed to be homogeneous over space. Since travel patterns …
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Thermal Transport Across Nano Engineered Solid-Liquid Interfaces
… transport across the nanoscale interfaces. As continuum approximation is not applicable for the nanoscale phenomena, molecular dynamics (MD) simulation is used to explore the mechanism of thermal transport at the nanometer scale interfaces. With the aid of MD simulation, several interfacial …
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Advancements for the Numerical Simulation of Free Fall Penetrometers and the Analysis of Wind Erosion of Sands
… a novel sand erosion model is derived using a continuum approximation and limit equilibrium analysis. The erosion law considers geotechnical parameters, the effects of slope, and moisture suction, in a combined manner. The proposed model is theoretically consistent with existing expressions in …
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Bus service design and schedule control
… and aims at providing high-level insights using continuum approximation (C.A.) to reduce the number of decision variables. For a hypothetical mono-centric demand distribution, the proposed system is shown to produce lower costs in terms of both agency investments and user costs, as compared to …
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Spatiotemporal random bipartite matching problems and applications in mobility systems
… to accommodate spatial heterogeneity via continuum approximation. The ST-RBMP is then formulated as an optimal control problem to allow dynamic decision making over time. A series of numerical experiments are conducted to demonstrate the effectiveness of the proposed ST-RBMP modeling …
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Last-Mile Logistics - Innovative Approaches to Network Optimization and Customer Service Offerings
… operations. Building on the extant literature on continuum approximation of optimal route distances, we propose closed-form adjustment factors which incorporate these non-trivial route efficiency effects that otherwise could not be captured by analytical considerations. To this end, we conduct …
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Sustainable and reliable design of large-scale complex logistics systems under competition and uncertainties
… We develop game-theoretical models based on Continuum Approximation (CA) to study a reliable competitive location problem where facilities are simultaneously subject to (i) symmetric or leader-follower types of competitions, and (ii) location-dependent probabilistic failures. An optimization …
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Planning service facilities and infrastructures under continuous traffic equilibrium
… computational efficiency, we first propose a continuum approximation (CA) model to find approximated solutions for large-scale instances. In contrast to most CA models which study uncapacitated fixed-charge location problems, we choose to focus on developing a solution approach for median-type …