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1
Abdelghany, Ahmed F. „Dynamic micro-assignment of travel demand with activity/trip chains“. Full text (PDF) from UMI/Dissertation Abstracts International Access restricted to users with UT Austin EID, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3023538.
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Morales, Juan Carlos. „Planning Robust Freight Transportation Operations“. Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14107.
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This research focuses on fleet management in freight transportation systems. Effective management requires effective planning and control decisions. Plans are often generated using estimates of how the system will evolve in the future; during execution, control decisions need to be made to account for differences between actual realizations and estimates. The benefits of minimum cost plans can be negated by performing costly adjustments during the operational phase. A planning approach that permits effective control during execution is proposed in this dissertation. This approach is inspired by recent work in robust optimization, and is applied to (i) dynamic asset management and (ii) vehicle routing problems.
In practice, the fleet management planning is usually decomposed in two parts; the problem of repositioning empty, and the problem of allocating units to customer demands. An alternative integrated dynamic model for asset management problems is proposed. A computational study provides evidence that operating costs and fleet sizes may be significantly reduced with the integrated approach. However, results also illustrate that not considering inherent demand uncertainty generates fragile plans with potential costly control decisions. A planning approach for the empty repositioning problem is proposed that incorporates demand and supply uncertainty using interval around nominal forecasted parameters. The intervals define the uncertainty space for which buffers need to be built into the plan in order to make it a robust plan. Computational evidence suggests that this approach is tractable.
The traditional approach to address the Vehicle Routing Problem with Stochastic Demands (VRPSD) is through cost expectation minimization. Although this approach is useful for building routes with low expected cost, it does not directly consider the maximum potential cost that a vehicle might incur when traversing the tour. Our approach aims at minimizing the maximum cost. Computational experiments show that our robust optimization approach generates solutions with expected costs that compare favorably to those obtained with the traditional approach, but also that perform better in worst-case scenarios. We also show how the techniques developed for this problem can be used to address the VRPSD with duration constraints.
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Kim, Kihong. „Recent Advances in Activity-Based Travel Demand Models for Greater Flexibility“. PDXScholar, 2018. https://pdxscholar.library.pdx.edu/open_access_etds/4225.
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Most existing activity-based travel demand models are implemented in a tour-based microsimulation framework. Due to the significant computational and data storage benefits, the demand microsimulation allows a greater amount of flexibility in terms of demographic market segmentation, temporal scale, and spatial resolution, and thus the models can represent a wider range of travel behavior aspects associated with various policies and scenarios. This dissertation proposes three innovative methodologies, one for each of the three key dimensions, to fulfill the greater level of details toward a more mature state of activity-based travel demand models.
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Xu, Suxiu, und 徐素秀. „Truthful, efficient auctions for transportation procurement“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/206443.
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Transportation procurement problem (TPP) is the problem of setting transportation service prices, delivery timing and quantity, and controlling costs and capacity to reduce empty movements and improve market efficiency. The purchase of transportation service is traditionally achieved using a request for proposal and long-term contracts. However, as business relationships become ever more flexible and dynamic, there has been an increasing need to hedge the risks of traditional transportation procurement such as entrance of new carriers and sudden drop in fuel price. This thesis proposes a holistic aution-based solution for the TPP.
Four typical scenarios are investigated. The first scenario incorporates bilateral bidding into auction mechanism design for multi-unit TPP. This scenario considers one-sided Vickrey-Clarke-Groves (O-VCG) combinatorial auctions for a complex transportation marketplace with multiple lanes. This scenario then designs three alternative multi-unit trade reduction (MTR) mechanisms for the bilateral exchange transportation marketplace where all the lanes are partitioned into distinct markets. Proposed mechanisms ensure incentive compatibility, individual rationality, budget balance and asymptotical efficiency.
The second scenario presents a double auction model for the TPP in a dynamic single-lane transportation environment. This scenario first addresses the TPP in a transportation spot market with stochastic but balanced or “symmetric” demand and supply. A periodic sealed double auction (PSDA) is proposed. This scenario then devises a modified PSDA (M-PSDA) to address the TPP with “asymmetric” demand and supply. The auctioneer is likely to gain higher profits from setting a relatively short auction length. However, it is optimal to run the auction (either PSDA or MPSDA) with a relatively large auction length, when maximizing either the social welfare or the utility of shippers and carriers (agents). When the degree of supply-demand imbalance is low, the auctioneer’s myopic optimal expected profit under supply-demand imbalance is larger than that under symmetric demand and supply.
This third scenario presents an auction-based model for the TPP in make-toorder systems. The optimality of dynamic base-stock type (S(x)-like policy) is established. The optimal allocation can be achieved by running an O-VCG auction or a first-price auction with closed-form reserve prices. By mild technical modifications, the results derived in the infinite horizon case can all be extended to the finite horizon case.
The fourth scenario proposes allocatively efficient auction mechanisms for the distributed transportation procurement problem (DTPP), which is generally the problem of matching demands and supplies over a transportation network. This scenario constructs an O-VCG combinatorial auction for the DTPP where carriers are allowed to bid on bundles of lanes. To simplify the execution of auction, this scenario next proposes a primal-dual Vickrey (PDV) auction based on insights from the known Ausubel auctions and the primal-dual algorithm. The PDV auction realizes VCG payments and truthful bidding under the condition of seller-submodularity, which implies that the effect of each individual carrier is decreasing when the coalition increases.published_or_final_version
Industrial and Manufacturing Systems Engineering
Doctoral
Doctor of Philosophy
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Fischer, Manfred M. „Computational Neural Networks: An attractive class of mathematical models for transportation research“. WU Vienna University of Economics and Business, 1997. http://epub.wu.ac.at/4158/1/WSG_DP_5797.pdf.
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Zhang, Lu, und 張露. „An integrated approach to empty container repositioning and vessel routing in marine transportation“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/206354.
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Cramer, Jay Alan 1957. „APPLICATION OF POLYHEDRAL DYNAMICS TO PEDESTRIAN ACCIDENTS (TRANSPORTATION)“. Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/277115.
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Qin, Jiefeng. „System dynamics representation of catastrophe and its application to transportation“. Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-05042010-020251/.
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Jiang, Yu, und 姜宇. „Reliability-based transit assignment : formulations, solution methods, and network design applications“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/207991.
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Foucart, Renaud. „Essays in product diversity and urban transportation“. Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209677.
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This dissertation is about games with a continuum of players and horizontal differentiation. The first chapter explains how price dispersion can be a feature of a competitive market with homogenous information and production costs. The second chapter extends the study to group consumption. The third chapter is about multiple equilibria in urban transportation.Doctorat en Sciences économiques et de gestion
info:eu-repo/semantics/nonPublished
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Dillon, Jeffrey Elliot. „The design of fixed routes in local area systems“. Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/25519.
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Uyar, Emrah. „Routing in stochastic environments“. Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26554.
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Thesis (Ph.D)--Industrial and Systems Engineering, Georgia Institute of Technology, 2009.Committee Co-Chair: Erera, Alan L.; Committee Co-Chair: Savelsbergh, Martin W. P.; Committee Member: Ergun, Ozlem; Committee Member: Ferguson, Mark; Committee Member: Kleywegt, Anton J.. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Hole, Arne Risa. „Modelling commuters' mode choice in Scotland“. Thesis, University of St Andrews, 2005. http://hdl.handle.net/10023/14115.
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This thesis contributes to the literature on the choice of transport mode for commuting trips, with special focus on the difference between urban and rural commuting in Scotland. The thesis begins by giving an overview of discrete choice theory and some empirical models consistent with this theory, before reviewing the literature on empirical applications of mode choice models for commuting trips. In the following, multinomial, nested and mixed logit models using data from a survey of commuters in the University of St Andrews are developed. The models are used to estimate aggregate mode-choice elasticities that can assist the development of efficient car reduction policies in St Andrews and other small towns in rural areas. The direct elasticities of the car mode are found to be comparable to estimates reported in studies of urban commuting, while the demand for public transport is found to be considerably more elastic. The value of in-vehicle travel time is found to be lower than in most studies of urban commuting, reflecting that the roads in the St Andrews area are relatively uncongested. Subsequently, current car drivers' willingness to use a Park and Ride service prior to the implementation of such a service are examined. The results show that the modal shift away from parking on-site will be small unless the new service is accompanied by measures aimed at making parking on-site less attractive such as introducing parking charges. Finally, the effect of the 'compact city' on modal split and congestion are examined. As well as making urban transport more sustainable as a result of an increase in the use of public transport, making cities more compact is found to contribute to lower levels of congestion in urban areas through a reduction in complex trip chains.
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Yim, Ka-wing, und 嚴家榮. „A reliability-based land use and transportation optimization model“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B34618879.
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Roberts, Craig Arnold. „Modeling the relationships between microscopic and macroscopic travel activity on freeways : bridging the gap between current travel demand models and emerging mobile emission models“. Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/32873.
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Li, Jiukun. „Impacts of e-shopping on urban transportation : an integrated network equilibrium model of shopping and travel choices“. HKBU Institutional Repository, 2004. http://repository.hkbu.edu.hk/etd_ra/517.
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Bakkalbasi, Omer. „Flow path network design and layout configuration for material delivery systems“. Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/25617.
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Peng, Zhongren. „A Simultaneous Route-level Transit Patronage Model: Demand, Supply, and Inter-route Relationship“. PDXScholar, 1994. https://pdxscholar.library.pdx.edu/open_access_etds/1159.
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It is observed that transit riders are responding to service changes while transit planning is responding to ridership changes, or that transit patronage and service supply are highly interrelated. It is also noticed that transit riders transfer from route to route, the introduction of new service may draw some riders from the existing routes, which implies transit patronage on a route is also affected by other parallel and intersecting routes. An analytic tool is needed to examine these complex relationships in the transit system. This study has developed a quantitative model by incorporating these interactions into a simultaneous system. The simultaneity of transit demand, supply and the interrelationship of inter-route effects are addressed in a three-equation simultaneous model: a demand equation, a supply equation and an equation for competing routes. These equations are estimated simultaneously using the three-stage-least-squares estimation method. The model is estimated at the route-segment level by the time of a day, and by the inbound and outbound directions. Data from Portland, Oregon metropolitan area are used as an extended case study. The socioeconomic and demographic data are allocated to an one-quarter-mile distance service area around a transit route by utilizing the technique of Geographic Information Systems (GIS). The data allocation significantly reduces the measurement error. Inter-route relationships are also identified using GIS. The estimation results show that a service change on a route increases the transit patronage on that route, but it also decreases the ridership on its competing routes, so the net effect of that service improvement is smaller than the ridership increase on the subject route. A conventional single equation model under-estimates the ridership responses on the subject route, and over-estimates the net patronage response. This study is the first research to discuss the net effects of a service change at the route level. The model can be implemented for system-level policy analysis and route-level service and land use planning. It is especially useful for "what-if" scenario analysis at the route level to simulate the ridership impacts of service and land use changes.
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Bevrani, Bayan. „Multi-criteria capacity assessment and planning models for multi-modal transportation systems“. Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/122895/1/Bayan_Bevrani_Thesis.pdf.
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This research provides a comprehensive set of methods for the capacity assessment of multi-modal transportation systems, which are easy to apply and can significantly reduce the time to perform a capacity analysis. This thesis developed multi-objective mathematical models that can evaluate the effect of parametric and structural changes and can assist planners to update and reconfigure multi-modal transportation systems considering the trade-off in different aspects of cost, time and functionality. The methods proposed in this thesis can help planners and decision-makers to identify the performance and capability of multiple modes of an integrated transportation system.
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Carbajal, Orozco Jose Antonio. „Transportation resource management in large-scale freight consolidation networks“. Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42758.
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This dissertation proposes approaches that enable effective planning and control of mobile transportation resources in large-scale consolidation networks. We develop models, algorithms, and methodologies that are applied to fleet sizing and fleet repositioning. Three specific but interrelated problems are studied. The first two relate to the trade-offs between fleet size and repositioning costs in transportation resource management, while the third involves a dynamic empty repositioning problem with explicit consideration of the uncertainty of future requirements that will be revealed over time.
Chapter 1 provides an overview of freight trucking, including the consolidation trucking systems that will be the focus of this research.
Chapter 2 proposes an optimization modeling approach for analyzing the trade-off between the cost of a larger fleet of tractors and the cost of repositioning tractors for a trucking company operating a consolidation network, such as a less-than-truckload (LTL) company. Specifically, we analyze the value of using extra tractor repositioning moves (in addition to the ones required to balance resources throughout the network) to attain savings in the fixed costs of owning or leasing a tractor fleet during a planning horizon. The primary contributions of the research in this chapter are that (1) we develop the first optimization models that explore the impact of fleet size reductions via repositioning strategies that have regularity and repeatability properties, and (2) we demonstrate that substantial savings in operational costs can be achieved by repositioning tractors in anticipation of regional changes in freight demand.
Chapter 3 studies the optimal Pareto frontiers between the fleet size and repositioning costs of resources required to perform a fixed aperiodic or periodic schedule of transportation requests. We model resource schedules in two alternative ways: as flows on event-based, time-expanded networks; and as perfect matchings on bipartite networks. The main contributions from this chapter are that (1) we develop an efficient re-optimization procedure to compute adjacent Pareto points that significantly reduces the time to compute the entire Pareto frontier of fleet size versus repositioning costs in aperiodic networks, (2) we show that the natural extension to compute adjacent Pareto points in periodic networks does not work in general as it may increase the fleet size by more than one unit, and (3) we demonstrate that the perfect matching modeling framework is frequently intractable for large-scale instances.
Chapter 4 considers robust models for dynamic empty-trailer repositioning problems in very large-scale consolidation networks. We investigate approaches that deploy two-stage robust optimization models in a rolling horizon framework to address a multistage dynamic empty repositioning problem in which information is revealed over time. Using real data from a national package/parcel express carrier, we develop and use a simulation to evaluate the performance of repositioning plans in terms of unmet loaded requests and execution costs. The main contributions from this chapter are that (1) we develop approaches for embedding two-stage robust optimization models within a rolling horizon framework for dynamic empty repositioning, (2) we demonstrate that such approaches enable the solution of very large-scale instances, and (3) we show that less conservative implementations of robust optimization models are required within rolling horizon frameworks.
Finally, Chapter 5 summarizes the main conclusions from this dissertation and discusses directions for further research.
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Orrell, James D. „GIS address-matching and transportation analysis“. PDXScholar, 1990. https://pdxscholar.library.pdx.edu/open_access_etds/4133.
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Geographic Information System (GIS) address-matching combined with other GIS processing offers new analytical opportunities in the area of transportation planning and analysis. Address-matching, an automated method for generating geographically-referenced (geocoded) point locations on a map from common tabular databases, can facilitate transportation analysis by providing a planning tool based on individual rather than aggregated spatial distributions more common to transportation issues.
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Fang, Yi. „An urban traffic network model using GIS technology“. Virtual Press, 1992. http://liblink.bsu.edu/uhtbin/catkey/845978.
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This creative project was proposed to develop a GIS model for transportation planning purposes with the ARC/INFO software. The urban street network in the GIS model was based on urban arterial systems in the city of Muncie, Indiana. The model was also expected to demonstrate the applicability of GIS technology in transportation planning. Several transportation planning techniques were tested with the model which included road and traffic data inventory, optimum pathing, road capacity analysis, traffic shift study modeling, and graphic presentation. The case study was targeted on road capacity analysis of urban arterial network as well as study of alternative traffic route for the urban route of State Road 32 in Muncie. The project began with an discussion of GIS technology, GIS application in planning, and ARC/INFO software programs. Then an urban street information model was developed in form of digital network in the computer database which could perform the functions of data inventory, spatial traffic analysis, and mapping manipulation. Finally the case studies were performed to demonstrate the application of this GIS network model. The findings and analysis results generated by GIS operation were used to evaluate the traffic conditions as well as to determine the feasibility of alternative route for State Road tables, ARC/INFO macro programs, traffic maps, and print-out of analysis results.Department of Urban Planning
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Al-Malik, Mohammed Saleh. „An investigation and development of a combined traffic signal control-traffic assignment model“. Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/21425.
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Carter, Andrew 1977. „A geographic and statistical analysis of the relationship between neighborhood and regional urban form and household car-dependency in Montreal /“. Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82693.
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The negative consequences (especially urban smog and global warming) of the heavy dependence on motorized vehicles of residents in urban areas across Canada and the United States have rightly motivated a great deal of research into potential policies aimed at reducing car ownership and use. This research focuses on the potential role of neighborhood and regional urban form and land use pattern in reducing car-dependency in cities. The study relies primarily on an origin-destination travel survey collected by the Agence Metropolitaine de Transport (AMT) in 1998, consisting of a 5% representative sample of residents living in the Montreal CMA. The first statistical model of household car-dependency is a multinomial logit model (MNL) of household automobile ownership levels on the Island of Montreal. The results suggest that neighborhood form has only a modest relationship automobile ownership levels. However, the location of a household's neighborhood relative to Montreal's CBD and whether an adult in it is employed there are both strongly associated with the number of vehicles a household owns, especially of multiple vehicles. The results indicate the importance of the spatial distribution and density of employment opportunities to vehicle ownership The second statistical model, an OLS regression of vehicle kilometers driven (VKD) by households for shopping purposes, found that neighborhood population density and proximity to a large retail cluster are both associated with meaningful reductions in motorized travel. Having said that, the results from both models suggest the most important determinants of household car-dependency are its socioeconomic and demographic composition. These findings suggest new suburban developments based on the principles of New Urbanism are unlikely to have any meaningful effect on car-dependency in urban areas.
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Brown, Rollins Patrick. „Predicting the ultimate axial resistance of single driven piles“. Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3025000.
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Chan, Kwong-yan Ian, und 陳光仁. „Developing a sustainable transport system in Hong Kong“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B29854076.
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Toriello, Alejandro. „Time decomposition of multi-period supply chain models“. Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/42704.
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Many supply chain problems involve discrete decisions in a dynamic environment. The inventory routing problem is an example that combines the dynamic control of inventory at various facilities in a supply chain with the discrete routing decisions of a fleet of vehicles that moves product between the facilities.
We study these problems modeled as mixed-integer programs and propose a time decomposition based on approximate inventory valuation. We generate the approximate value function with an algorithm that combines data fitting, discrete optimization and dynamic programming methodology. Our framework allows the user to specify a class of piecewise linear, concave functions from which the algorithm chooses the value function. The use of piecewise linear concave functions is motivated by intuition, theory and practice. Intuitively, concavity reflects the notion that inventory is marginally more valuable the closer one is to a stock-out. Theoretically, piecewise linear concave functions have certain structural properties that also hold for finite mixed-integer program value functions. (Whether the same properties hold in the infinite case is an open question, to our knowledge.) Practically, piecewise linear concave functions are easily embedded in the objective function of a maximization mixed-integer or linear program, with only a few additional auxiliary continuous variables. We evaluate the solutions generated by our value functions in a case study using maritime inventory routing instances inspired by the petrochemical industry.
The thesis also includes two other contributions. First, we review various data fitting optimization models related to piecewise linear concave functions, and introduce new mixed-integer programming formulations for some cases. The formulations may be of independent interest, with applications in engineering, mixed-integer non-linear programming, and other areas. Second, we study a discounted, infinite-horizon version of the canonical single-item lot-sizing problem and characterize its value function, proving that it inherits all properties of interest from its finite counterpart. We then compare its optimal policies to our algorithm's solutions as a proof of concept.
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Brizendine, Laora Dauberman. „Low probability-high consequence considerations in a multiobjective approach to risk management“. Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-07112009-040353/.
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Nowak, Maciek A. „The Pickup and Delivery Problem with Split Loads“. Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7223.
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This dissertation focuses on improvements in vehicle routing that can be gained by allowing multiple vehicles to service a common load. We explore how costs can be reduced through the elimination of the constraint that a load must be serviced by only one vehicle. Specifically, we look at the problem of routing vehicles to service loads that have distinct origins and destinations, with no constraint on the amount of a load that a vehicle may service. We call this the Pickup and Delivery Problem with Split Loads (PDPSL). We model this problem as a dynamic program and introduce structural results that can help practitioners implement the use of split loads, including the definition of an upper bound on the benefit of split loads. This bound indicates that the routing cost can be reduced by at most one half when split loads are allowed. Furthermore, the most benefit occurs when load sizes are just above one half of vehicle capacity.
We develop a heuristic for the solution of large scale problems, and apply this heuristic to randomly generated data sets. Various load sizes are tested, with the experimental results supporting the finding that most benefit with split loads occurs for load sizes just above one half vehicle capacity. Also, the average benefit of split loads is found to range from 6 to 7% for most data sets. The heuristic was also tested on a real world example from the trucking industry. These tests reveal the benefit of both using split loads and allowing fleet sharing. The benefit for split loads is not as significant as with the random data, and the various business rules added for this case are tested to find those that have the most impact. It is found that an additional cost for every stop the vehicle makes strictly limits the potential for benefit from split loads. Finally, we present a simplified version of the PDPSL in which all origins are visited prior to any destination on a route, generalizing structural results from the Split Delivery Vehicle Routing Problem for this problem.
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Yen, Jeffrey Lee. „A system model for assessing water consumption across transportation modes in urban mobility networks“. Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39527.
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Energy and environmental impacts are two factors that will influence urban region composition in the near future. One emerging issue is the effect on water usage resulting from changes in regional or urban transportation trends. With many regions experiencing stresses on water availability, transportation planners and users need to combine information on transportation-related water consumption for any region and assess potential impacts on local water resources from the expansion of alternative transportation modes. This thesis will focus on use-phase water consumption factors for multiple vehicle modes, energy and fuel pathways, roads, and vehicle infrastructure for a given transportation network.
While there are studies examining life cycle impacts for energy generation and vehicle usage, few repeatable models exist for assessing overall water consumption across several transportation modes within urban regions. As such, the question is: is it possible to develop a traceable decision support model that combines and assesses water consumption from transportation modes and related mobility infrastructure for a given mobility network? Based on this, an object-oriented system model of transportation elements was developed using the Systems Modeling Language (SysML) and Model-Based Systems Engineering principles to compare water consumption across vehicle modes for assessing the resiliency of existing infrastructure and water resources.
To demonstrate the intent of this model, daily network usage water consumption will be analyzed for current and alternative network scenarios projected by policies regarding the expansion of alternative energy. The model is expected to show variations in water consumption due to fluctuations in energy pathways, market shares, and driving conditions, from which the model should help determine the feasibility of expanding alterative vehicles and fuels in these networks. While spatially explicit data is limited compared to the national averages that are used as model inputs, the analytical framework within this model closely follows that of existing assessments and the reusable nature of SysML model elements allows for the future expansion of additional transportation modes and infrastructure as well as other environmental analyses.
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Kerin, Paul D. „A spatial economic analysis of the Eyre Peninsula grain handling and transportation system“. Title page, abstract and contents only, 1985. http://web4.library.adelaide.edu.au/theses/09ECM/09ecmk39.pdf.
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Michaud, Darryl Joseph. „Driver Distraction in Microsimulation of a Mid-Block Pedestrian Crossing“. Thesis, Portland State University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10830985.
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Traffic simulation has become an invaluable part of the traffic engineering toolbox. However, the majority of driver models are designed to recreate traffic performance based on interactions among vehicles. In keeping with this pursuit, most are fundamentally built to avoid collisions. This limits the applicability of using these models for addressing safety concerns, especially those regarding pedestrian safety performance. However, by explicitly including some of the sources of human error, these limitations can, in theory, be overcome. While much work has been done toward including these human factors in simulation platforms, one key aspect of human behavior has been largely ignored: driver distraction.
This work presents a novel approach to inclusion of driver distraction in a microsimulation or agent-based model. Distributions of distraction events and inter-distraction periods are derived from eye-glance data collected during naturalistic driving studies. The developed model of distraction is implemented – along with perception errors, visual obstructions, and driver reaction times – in a simulated mid-block pedestrian crossing.
The results of this simulation demonstrate that excluding any of these human factors from the implemented driver model significantly alters conflict rates observed in the simulation. This finding suggests that inclusion of human factors is important in any microsimulation platforms used to analyze pedestrian safety performance.
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Munyakazi, Justin Bazimaziki. „Transport modelling in the Cape Town Metropolitan Area“. Thesis, University of the Western Cape, 2005. http://etd.uwc.ac.za/index.php?module=etd&.
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The use of MEPLAN by the Metropolitan Transport Planning Branch of the Cape Town City Council since 1984 was not successful due to apartheid anomalies. EMME/2 was then introduced in 1991 in replacement of MEPLAN. The strengths and weaknesses of both MEPLAN and EMME/2 are recorded in this study.
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Bula, Gustavo Alfredo. „Vehicle Routing for Hazardous Material Transportation“. Thesis, Troyes, 2018. http://www.theses.fr/2018TROY0014.
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L'objectif de cette thèse est d'étudier le problème du transport de matières dangereuses (HazMat) vu comme un problème de tournées de véhicules à flotte hétérogène. Les décisions pour ce type de transport comportent des objectifs différents, parfois antagonistes. Deux sont pris en compte dans ce travail, le coût et le risque. La première tâche entreprise a été la formulation d'un modèle mathématique pour la minimisation du risque, qui dépend du type de véhicule, du matériel transporté et du changement de charge lorsque le véhicule passe d'un client à un autre. Une approximation linéaire par morceaux est utilisée pour conserver une formulation de programmation linéaire en nombres entiers mixtes.Des méthodes hybrides basées sur des explorations de voisinages sont proposées pour traiter la minimisation du risque. Cela comprend l'étude des structures de voisinages et le développement d'un algorithme de descente à voisinages variables (VND) pour la recherche locale, ainsi qu'un mécanisme de perturbation des solutions. Une post-optimisation est appliquée pour améliorer la qualité des solutions obtenues.Enfin, deux approches, un algorithme basé sur la dominance multi-objectif et une méta-heuristique de type epsilon- contrainte, sont développées pour traiter la version multi-objectif. Deux mesures de performance sont utilisées : l'hyper volume et la ∆-métrique. Les approximations de fronts montrent qu'une légère augmentation du coût total des tournées peut entraîner une forte réduction en pourcentage des risquesThe main objective of this thesis is to study the hazardous materials (HazMat) transportation problem considered as a heterogeneous fleet vehicle routing problem. HazMat transportation decisions comprise different and sometimes conflicting objectives. Two are considered in this work, the total routing cost and the total routing risk. The first task undertaken was the formulation of a mathematical model for the routing risk minimization, which depends on the type of vehicle, the material being transported, and the load change when the vehicle goes from one customer to another. A piecewise linear approximation is employed to keep a mixed integer linear programing formulation.Hybrid solution methods based on neighborhood search are explored for solving the routing risk minimization. This includes the study of neighborhood structures and the development of a Variable Neighborhood Descent (VND) algorithm for local search, and a perturbation mechanism (shaking neighborhoods). A post-optimization procedure is applied to improve the solution quality.Finally, two different solution approaches, a multi-objective dominance-based algorithm and a meta-heuristic epsilon-constraint method are employed for addressing the multi-objective version of the problem. Two performance metrics are used: the hyper volume and the ∆-metric. The front approximations show that a small increment in the total routing cost can produce a high reduction in percentage of the expected consequences given the probability of a HazMat transportation incident
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Husted, Christopher. „Improving the efficiency of assigning vehicles to auto carrier loads : a decision support system“. Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/18129.
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Thesis (MBA)--Stellenbosch University, 2008.ENGLISH ABSTRACT: Auto Carrier Transport (ACT) is the motor ferrying division of Grindrod South Africa (Pty) Ltd and is contracted to transport the product of 15 different vehicle manufacturers. The division is responsible for ensuring that the combined annual volumes of each contract, totalling over 300 000 vehicles per year, are delivered to the right place, at the right time, and in the right condition. ACT's operating mandate thus focuses on the outbound logistics of new vehicles, which implies moving cars from either the local manufacturing plants, or from the import facilities at the ports, to the respective dealer networks all across Southern Africa. One of the key operational processes regarding the transportation of vehicles is the allocation of cars to carrier loads, also known as load building. Once cars have been allocated to a load, a carrier is then used to transport the load. The existing load building operation is completely manual, with operators simply assigning cars to loads as best they see fit. No support systems exist. Thus, given the complexity of the load building problem, and the manual processes used, existing load building practices result in suboptimal payload performances. A Linear Programming Model was developed to improve the manner in which vehicles are categorised, and then assigned to loads. When compared against the results of load building operators, it was found that the model could potentially improve the company's contribution margin by 5.8 percent.
AFRIKAANSE OPSOMMING: Auto Carrier Transport (ACT) is die motorvoertuig vervoerafdeling van Grindrod Suid Afrika (Edms) Bpk en word gekontrakteer vir die vervoer van die produkte van 15 verskillende motorvervaardigers. Die afdeling is verantwoorde1ik om te verseker dat die jaarlikse volume van elke kontrak (met 'n gekombineerde volume van meer as 300 000 motorvoertuie per jaar) betyds afgelewer word, op die regte plek en in die regte toestand. ACT se operasionele mandaat fokus dus op die uitgaande logistiek van nuwe motorvoertuie met die implikasie dat motorvoertuie vanaf die plaaslike vervaardingsaanleg, of die invoer fasiliteit by die hawens, na die ooreenstemende handelaarsnetwerke in Suider Afrika vervoer word. Een van die kern operasionele prosesse rakende die vervoer van motorvoertuie, wat bekendstaan as vragtoekening, is die toedeling van motorvoertuie tot vragmotor vragte. Sodra 'n motorvoertuig aan 'n vrag toegeken is, word dit deur middel van 'n vragmotor vervoer. Die bestaande vragtoekeningsproses word per hand uitgevoer deur operateurs wat eenvoudig motorvoertuie aan vragte toedeel soos hulle goeddink sonder die gebruik van enige besluitnemingsondersteuningstelsels. Aangesien vragtoekening 'n baie komplekse probleem is wat per hand uitgevoer word, is die resultate suboptimaal. 'n Lineêre programeeringsmodel is ontwikkel om die klassifikasie van motorvoertuie te verbeter waarna die motorvoertuie aan vragte toegeken word. In 'n vergelyking tussen die model se resultate en die van die operateurs is daar bevind dat die model die maatskappy se wins per eenheid met 5.8 persent kan verbeter.
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Broach, Joseph. „Travel Mode Choice Framework Incorporating Realistic Bike and Walk Routes“. PDXScholar, 2016. https://pdxscholar.library.pdx.edu/open_access_etds/2702.
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For a number of reasons--congestion, public health, greenhouse gas emissions, energy use, demographic shifts, and community livability to name a few--the importance of walking and bicycling as transportation options will only continue to increase. Currently, policy interest and infrastructure funding for nonmotorized modes far outstrip our ability to model bike and walk travel. To ensure scarce resources are used most effectively, accurate models sensitive to key policy variables are needed to support long-range planning and project evaluation, and to continue adding to our growing understanding of key factors driving walk and bike behavior. This research attempts to synthesize and advance the state of the art in trip-based, nonmotorized mode choice modeling.
Over the past fifteen years, efforts to model the decision to walk or bike on a given trip have been hampered by the lack of a comprehensive behavioral framework and inconsistency in measurement scales and model specification. This project develops a mode choice behavioral framework that acknowledges the importance of attributes along the specific walk and bike routes that travelers are likely to consider, in addition to more traditional area-based measures of travel environments. The proposed framework is applied to a revealed preference, GPS-based travel dataset collected from 2010-2013 in Portland, Oregon. Measurement of nonmotorized trip distance, built environment, tour-level variables, and attitudinal attributes as well as mode availability are explicitly addressed. Route and mode choice models are specified using discrete choice techniques, and predicted walking and bicycling routes are tested as inputs to various mode choice models.
Results suggest strong potential for predicted route measures to enhance walk and bicycle mode choice modeling. Findings also support the specific notion that bicycle and pedestrian infrastructure contribute not only to route choice but also to the choice of whether to bike or walk. For decisions to bicycle, availability of low-traffic routes may be particularly important to women. Model results further indicate that land use and built environments around trip ends and a person’s home still have important effects on nonmotorized travel when controlling for route quality. Both route and area travel environment impacts are mostly robust to the inclusion of residential self-selection variables, consistent with the idea that built environment differences matter even for households that choose to live in a walkable or bikeable neighborhood. The combination of area and route-based built environment measures alongside trip context, sociodemographic, and attitudinal attributes provides a new perspective on nonmotorized travel behavior relevant to both policy and practice.
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Kressner, Josephine D. „Leveraging targeted marketing data in travel demand modeling: validation and applications“. Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51870.
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To date, the collection of comprehensive household travel data has been a challenge for most metropolitan planning organizations (MPOs) and state departments of transportation (DOTs) due mainly to high costs. Urban population growth, the expansion of metropolitan regions, and the general unwillingness of the public to complete surveys conflict with limited public funds. The purpose of this research is to leverage targeted marketing data, sometimes referred to as consumer data or just simply marketing data, for travel demand modeling applications. This research reveals a first step in exploring the use of targeted marketing data for representing population characteristics of a region.
Four studies were completed: an aggregate validation, a household-level validation for hard-to-reach population groups, an airport passenger model, and a residential location choice model. The two validation studies of this work suggest that targeted marketing data are similar to U.S. Census data at small geographic levels for basic demographic and socioeconomic information. The studies also suggest that the existing coverage errors are at least similar, if not lower than, the levels of those in household travel surveys used today to build travel demand models. The two application studies of this work highlight the benefits of the targeted marketing data over traditional household travel surveys and U.S. Census data particularly well, including the additional behavioral information available at the household-level and the very large sample sizes.
These results suggest that the combination of targeted marketing data with other third-party and non-traditional data could be particularly powerful. It offers tremendous opportunities to enhance, or even transform, existing travel demand modeling systems and data collection practices. Inexpensive, up-to-date, and detailed data would allow researchers and decision-makers alike to better understand travel behavior and to be more equipped to make important transportation-related decisions that affect our lives each day.
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Forooqi, A. Masood. „Ridership studies for the proposed Florida high speed rail system“. FIU Digital Commons, 1990. http://digitalcommons.fiu.edu/etd/3254.
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Florida, the fourth largest and sunshine state, is growing at the rate of 800 new residents daily.!! By the year 2000 the population is estimated to be 16 Million, and the annual tourists at 80 Million, generating 40 Million trips.
The proposed High Speed Rail will connect Miami and West Palm Beach to Orlando and Tampa. This 325-mile corridor represents 70 % of all the "Socio-Economic Resources" of the whole of Florida and the trend will continue well into the next century. The Miami-Orlando ride will reduce to 2 hours speeding at up to 150 mph. It will be operational by 1995 and the system is estimated to cost 4.6 Billion Dollars.
One of the major problems encountered by the new High Speed Rail (HSR) is the "RIDERSHIP FORECASTING," In the United States there is a lack of current information about the Total Volume of Intercity Trips and the Specific Characteristics of the Trips that determines a willingness to use HSR. The Quality, Comprehensiveness, and Acceptability, by the forecasts must be sufficient to generate Public Support, Confidence, and Response for the Implementation of HSR.
The THESIS discusses the various Ridership Forecasting Techniques and chooses the “Most Suitable Model” applicable to conditions in South and Central Florida.
A “Model Choice Based Model” is selected called, “THE LOGIT FUNCTION”, which takes into account, the Floridian Choice of available Travel Modes, and the Factors Affecting the Manner of the “Decision making Process”, in Favour of a Particular Mode. Evaluating Business and Non-Business Travel for the Internal Trips, (including the Induced Demand and the Short Trips) and the External Trips. The External and Short Trips were Not considered by Previous Studies. The standard guidelines for “Revenue and Ridership Forecasting,” by High Speed Rail Association are closely followed in this Study. Due consideration is also given to Socio-Economic data involving population, wealth, average per capita income, number of families, size of labor force, number of hotel / motel rooms and college enrollment. A Survey was carried out, to collect the data and to test the Sensitivity, under given set of conditions and scenarios.
The studies conclude that HSR is a Feasible Project and by the year 2000, the Ridership will be 3.8 Million Annual Trips. The future studies will continue to improve the results, as an individual’s attitude and response towards HSR Travel becomes better known and recorded in Florida
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Hallmark, Shauna L. „Analysis and prediction of individual vehicle activity for microscopic traffic modeling“. Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/20736.
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Johnson, Pamela Christine. „Bicycle Level of Service: Where are the Gaps in Bicycle Flow Measures?“ PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1975.
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Bicycle use is increasing in many parts of the U.S. Local and regional governments have set ambitious bicycle mode share goals as part of their strategy to curb greenhouse gas emissions and relieve traffic congestion. In particular, Portland, Oregon has set a 25% mode share goal for 2030 (PBOT 2010). Currently bicycle mode share in Portland is 6.1% of all trips. Other cities and regional planning organizations are also setting ambitious bicycle mode share goals and increasing bicycle facilities and programs to encourage bicycling. Increases in bicycle mode share are being encouraged to increase. However, cities with higher-than-average bicycle mode share are beginning to experience locations with bicycle traffic congestion, especially during peak commute hours. Today, there are no established methods are used to describe or measure bicycle traffic flows.
In the 1960s, the Highway Capacity Manual (HCM) introduced Level of Service (LOS) measurements to describe traffic flow and capacity of motor vehicles on highways using an A-to-F grading system; "A" describes free flow traffic with no maneuvering constraints for the driver and an "F" grade corresponds to over capacity situations in which traffic flow breaks down or becomes "jammed". LOS metrics were expanded to highway and road facilities, operations and design. In the 1990s, the HCM introduced LOS measurements for transit, pedestrians, and bicycles. Today, there are many well established and emerging bicycle level of service (BLOS) methods that measure the stress, comfort and perception of safety of bicycle facilities. However, it was been assumed that bicycle traffic volumes are low and do not warrant the use of a LOS measure for bicycle capacity and traffic flow. There are few BLOS methods that take bicycle flow into consideration, except for in the case of separated bicycle and bicycle-pedestrian paths.
This thesis investigated the state of BLOS capacity methods that use bicycle volumes as a variable. The existing methods were applied to bicycle facility elements along a corridor that experiences high bicycle volumes in Portland, Oregon. Using data from the study corridor, BLOS was calculated and a sensitivity analysis was applied to each of the methods to determine how sensitive the models are to each of the variables used. An intercept survey was conducted to compare the BLOS capacity scores calculated for the corridor with the users' perception. In addition, 2030 bicycle mode share for the study corridor was estimated and the implications of increased future bicycle congestion were discussed. Gaps in the BLOS methods, limitations of the thesis study and future research were summarized.
In general, the existing methods for BLOS capacity are intended for separated paths; they are not appropriate for existing high traffic flow facilities. Most of the BLOS traffic flow methods that have been developed are most sensitive to bicycle volumes. Some of these models may be a good starting point to improve BLOS capacity and traffic flow measures for high bicycle volume locations. Without the tools to measure and evaluate the patterns of bicycle capacity and traffic flow, it will be difficult to monitor and mitigate bicycle congestion and to plan for efficient bicycle facilities in the future. This report concludes that it is now time to develop new BLOS capacity measures that address bicycle traffic flow.
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Mendes, Wagner Schalch. „Regulação de trens em sistemas metroviarios“. [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259748.
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Orientador: Rafael Santos MendesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: O problema de regulação de trens é particularmente importante entre os problemas de escalonamento encontrados nos sistemas de transporte metroviários, sendo caracterizados por trens percorrendo regiões urbanas levando passageiros de uma localização para outra. Se o intervalo entre trens desejado, tempos de parada em plataformas e os tempos de percurso entre plataformas são determinados e conhecidos a-priori, a solução de estado estável (tabela horária) pode ser calculada. Entretanto, sistemas reais estão sujeitos a perturbações como passageiros impedindo o fechamento de portas, falhas mecânicas ou elétricas, etc., que podem desviar os trens do estado estável. Nesse contexto, esse trabalho está direcionado para a determinação de uma lei de controle, i.e., uma lei para a determinação dos instantes de chegada e partida de cada trem em cada plataforma nos ciclos do sistema para restabelecer e manter a tabela horária (solução de referência). A lei de controle proposta está baseada nos conceitos da álgebra maxplus. Os instantes desejáveis de chegada e partida de cada trem em cada plataforma são calculados a partir dos últimos instantes de ocorrência dos eventos do sistema e de um conjunto de matrizes definido na álgebra max-plus.
Abstract: The train regulation problem is of particular importance among the scheduling problems found in mass transit systems, being characterized by trains running in urban regions taking passengers from one location to another. If the desired headway between trains, dwell-times in platforms and running times between platforms are determined and known a-priori, the steady state solution (timetable) can be calculated. However, real systems are subject to disturbances such as passengers preventing doors from closing, mechanical or electrical failures, etc., that can deviate the trains from the steady state. In this context, this work is concerned with the determination of a control law, i.e., a law for the determination of the arrival and departure times of each train on each platform in the system's cycles in order to reestablish and maintain the timetable (reference solution). The proposed control law is based on max-plus algebra concepts. The desired arrival and departure times of each train on each platform are calculated from the last occurrence instants of the system's events and from a set of matrices defined in max-plus algebra.
Mestrado
Automação
Mestre em Engenharia Elétrica
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Burgain, Pierrick Antoine. „On the control of airport departure operations“. Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37261.
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This thesis is focused on airport departure operations; its objective is to assign a value to surface surveillance information within a collaborative framework.
The research develops a cooperative concept that improves the control of departure operations at busy airports and evaluates its merit using a classical and widely accepted airport departure model. The research then assumes departure operations are collaboratively controlled and develops a stochastic model of taxi operations on the airport surface. Finally, this study investigates the effect of feeding back different levels of surface surveillance information to the departure control process. More specifically, it examines the environmental and operational impact of aircraft surface location information on the taxi clearance process. Benefits are evaluated by measuring and comparing engine emissions for given runway utilization rates.
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Delaneze, Marcelo Elias [UNESP]. „Modelagem dinâmica espacial aplicada na avaliação das mudanças da cobertura da terra no entorno de dutos utilizando autômatos celulares: estudo de caso duto ORBEL“. Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/92738.
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delaneze_me_me_rcla.pdf: 1472015 bytes, checksum: 1596836f4441d15a50d94daf73c5a740 (MD5)Agência Nacional do Petróleo, Gás Natural e Biocombustíveis (ANP)
A obtenção de informação sobre as condições da rede dutoviária representa papel primordial na operação dos dutos, não só com o propósito de manter a eficiência operacional, mas também, para a minimização dos riscos associados a possíveis acidentes, tanto decorrentes dos processos naturais quanto de causas antrópicas relacionadas ao uso e cobertura da terra. Neste sentido, o emprego de modelos matemáticos em estudos ambientais gera importantes contribuições científicas ao planejamento ordenado de uma área, uma vez que ajudam a entender o impacto das mudanças no uso e cobertura da terra e a prever alterações futuras nos ecossistemas. A área de estudo compreende porções dos municípios de Duque de Caxias, Belford Roxo e Nova Iguaçu e tem por objetivo realizar experimentos de mudanças da cobertura da terra em médio prazo (10 anos) para a faixa de dutos ORBEL. A modelagem realizada neste trabalho foi desenvolvida no software Dinamica-EGO, utilizando como entrada mapas classificados de cobertura da terra, obtidos através de imagens do satélite Landsat 5/TM, e variáveis espaciais para explicar as mudanças ocorridas na cobertura da terra. Para a calibração do modelo, utilizou-se o método de pesos de evidência, disponível no Dinamica-EGO, primeiramente categorizando-se os mapas de variáveis contínuas e, posteriormente, calculando-se os pesos de evidência. Valores positivos favorecem determinada transição, enquanto valores negativos indicam baixa probabilidade de transição, e valores próximos a zero não exercem efeito. A validação do modelo se deu pelo método de similaridade fuzzy, com decaimento exponencial. Os resultados mostram que, para os dois períodos analisados (1987-1998 e 1998-2010), a taxa de mudança para a transição “vegetação arbórea para outros” é bem maior do que para...
Reliable information about conditions of pipeline network represents a major role in the operation of pipelines, not only in order to maintain operational efficiency, but also to minimize the risks associated with possible accidents such as rupture of the ducts due to landslides or mudslides mass block, causing damage to humans and the environment. The use of mathematical models in environmental studies allows significant scientific contributions to the physical planning of an area, since they help to understand the impact of changes in land use and land cover and predict future trends of changes in ecosystems. The study area includes portions of the municipalities of Duque de Caxias, Nova Iguaçu, and Belford Roxo and aims to carry out experiments in land-cover changes in the medium-term (10 years) within the catchment area of ORBEL pipelines. The modeling performed in this work was developed using the software Dinamica-EGO, using as input classified land cover maps obtained from Landsat 5/TM satellite images as well as spatial variables to explain the observed changes in land cover. For the model calibration, we used the method of weights of evidence that is available at Dinamica-EGO. Initially, the maps of continuous variables were categorized according to discrete ranges, which were then employed for the calculation of the respective positive weights of evidence. Positive values foster certain transitions, while negative values indicate low probability of transition, and values close to zero have no effect on changes. Model validation was executed by means of the fuzzy similarity method using exponential decay. The results show that for the two study periods (1987-1998 and 1998-2010) the rate of change for the transition 'others to woody vegetation' is much higher than for the other transitions observed in the same... (Complete abstract click electronic access below)
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Vieira, Kely Plucinski. „Estratégias de participação em leilões combinatoriais aplicadas em um problema de transporte de derivados de petróleo“. Universidade Tecnológica Federal do Paraná, 2012. http://repositorio.utfpr.edu.br/jspui/handle/1/560.
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Pesquisas recentes mostram que abordagens baseadas em sistemas multiagentes (SMA) e mecanismos de mercado como leilões são eficazes para encontrar soluções factíveis para problemas de planejamento em cadeias de suprimento. Esta dissertação aborda a utilização do paradigma de SMA baseado em Leilões Combinatoriais e o uso de estratégias de participação em leilões na resolução do problema de transporte de derivados de petróleo em uma rede multimodal da PETROBRAS – Petróleo Brasileiro S/A, denominado Problema de Transporte de Derivados de Petróleo Simplificado (PTDPS), que se caracteriza como um problema de planejamento em cadeias de suprimento. Em leilões combinatoriais, a determinação do vencedor é um problema NP-Completo sem algoritmos de aproximação, cujo custo computacional aumenta com o número de ofertas recebidas pelo leiloeiro. Este trabalho tem por objetivo aumentar o escopo de aplicação de leilões combinatoriais em problemas de planejamento pelo uso de uma estratégia heurística de participação em leilões, além de servir como uma ferramenta de apoio à tomada de decisão por especialistas da indústria petrolífera. Os resultados obtidos a partir da aplicação do SMA desenvolvido em uma série de cenários para a estratégia proposta (avaliação da necessidade global) e outras de referência (geral - todos os leilões possíveis - e gulosa – somente um leilão) foram comparados entre si e demonstram que a utilização da estratégia proposta reduz o tempo de processamento em relação à estratégia geral e sem perda da qualidade da solução em comparação com as estratégias geral e gulosa. Outras contribuições deste trabalho são um SMA para realizar o planejamento do transporte de derivados de petróleo tendo como modelo de negociação o mecanismo de leilões combinatoriais e a proposição de um modelo descentralizado onde diversos leilões combinatoriais podem ser executados simultaneamente.Recent researches have shown that approaches based on multi-agent systems (MAS) and market mechanisms like auctions are efficient on the resolution of planning problems in supply chains. This work uses the combinatorial auction-based MAS paradigm and participation strategies in auctions for solving the problem of transporting oil derivatives of PETROBRAS - Petroleo Brasileiro S/A, called Simplified Problem of Transporting Oil Derivatives (SPTOD), which is characterized as a planning problem in supply chains. In combinatorial auctions, the winner determination is a NP-Complete problem without approximation algorithms, whose computational cost increases with the number of bids received by the auctioneer. In this context, this work aims at enlarging the scope of application of combinatorial-auction mechanisms in planning problems by using a heuristic strategy for participation in auctions, besides serving as a support tool for decision-making process by specialists of industrial oil. The results were drawn from several scenarios where the MAS was used with the proposed strategy (global evaluation of needs) and with other strategies for comparison (general – all possible auctions – and greedy – only one auction). The results show that the use of the proposed strategy reduces the processing time when compared to the general strategy and that the quality of the solution is preserved in comparison with the general and greedy strategies. Other contributions of this work are the development of a MAS to realize the planning of transporting oil derivatives between producing and consuming basis having as negotiation model the combinatorial auction-based mechanism and a proposition of a decentralized model where several combinatorial auctions can be run simultaneously.
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MacFarlane, Gregory Stuart. „Using big data to model travel behavior: applications to vehicle ownership and willingness-to-pay for transit accessibility“. Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51804.
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The transportation community is exploring how new "big'' databases constructed by companies or public administrative agencies can be used to better understand travelers' behaviors and better predict travelers' responses to various transportation policies. This thesis explores how a large targeted marketing database containing information about individuals’ socio-demographic characteristics, current residence attributes, and previous residential locations can be used to investigate research questions related to individuals' transportation preferences and the built environment. The first study examines how household vehicle ownership may be shaped by, or inferred from, previous behavior. Results show that individuals who have previously lived in dense ZIP codes or ZIP codes with more non-automobile commuting options are more likely to own fewer vehicles, all else equal. The second study uses autoregressive models that control for spatial dependence, correlation, and endogeneity to
investigate whether investments in public transit infrastructure are associated
with higher home values. Results show that willingness-to-pay estimates obtained from the general spatial Durbin model are less certain than comparable estimates obtained through ordinary least squares. The final study develops an empirical framework to examine a housing market's resilience to price volatility as a function of transportation accessibility. Two key modeling frameworks are considered. The first uses a spatial autoregressive model to investigate the relationship between a home's value, appreciation, and price stability while controlling for endogenous missing regressors. The second uses a latent class model that considers all these attributes simultaneously, but cannot control for endogeneity.
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Bennett, Ashlea R. „Home health care logistics planning“. Diss., Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/33989.
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This thesis develops quantitative methods which incorporate transportation modeling for tactical and operational home health logistics planning problems. We define home health nurse routing and scheduling (HHNRS) problems, which are dynamic periodic routing and scheduling problems with fixed appointment times, where a set of patients must be visited by a home health nurse according to a prescribed weekly frequency for a prescribed number of consecutive weeks during a planning horizon, and each patient visit must be
assigned an appointment time belonging to an allowable menu of equally-spaced times. Patient requests are revealed incrementally, and appointment time selections must be made without knowledge of future requests. First, a static problem variant is studied to understand the impact of fixed appointment times on routing and
scheduling decisions, independent of other complicating factors in the HHNRS problem. The costs of offering fixed appointment times are
quantified, and purely distance-based heuristics are shown to have potential limitations for appointment time problems unless proposed arc cost transformations are used. Building on this result, a new rolling horizon capacity-based heuristic is developed for HHNRS problems. The heuristic considers interactions between travel times, service times, and the fixed appointment time menu when inserting appointments for currently revealed patient requests into partial
nurse schedules. The heuristic is shown to outperform a distance-based heuristic on metrics which emphasize meeting as much patient demand as possible.
The home health nurse districting (HHND) problem is a tactical planning problem which influences HHNRS problem solution quality. A set of geographic zones must be partitioned into districts to be served by home health nurses, such that workload is balanced across districts and nurse travel is minimized. A set partitioning model for HHND is formulated and a column generation heuristic is developed which integrates ideas from optimization and local search. Methods for estimating district travel and workload are developed and implemented within the heuristic, which outperforms local search
on test instances.
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Dewez, Sophie. „On the toll setting problem“. Doctoral thesis, Universite Libre de Bruxelles, 2004. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211104.
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In this thesis we study the problem of road taxation. This problem consists in finding the toll on the roads belonging to the government or a private company in order to maximize the revenue. An optimal taxation policy consists in determining level of tolls low enough to favor the use of toll arcs, and high enough to get important revenues. Since there are twolevels of decision, the problem is formulated as a bilevel bilinear program.Doctorat en sciences, Orientation recherche opérationnelle
info:eu-repo/semantics/nonPublished
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Elahi, Behin. „Integrated Optimization Models and Strategies for Green Supply Chain Planning“. University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1467266039.
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Polli, Helton Luis. „Otimização do transporte de derivados claros de petróleo em rede de dutos utilizando programação linear inteira mista“. Universidade Tecnológica Federal do Paraná, 2014. http://repositorio.utfpr.edu.br/jspui/handle/1/799.
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Este trabalho utiliza Programação Linear Inteira Mista (PLIM) para propor uma nova abordagem para a atividade de sequenciamento de bateladas em uma rede de dutos real. O modelo proposto está imerso em uma estrutura de otimização que auxilia a tarefa de programação scheduling do transporte de derivados leves, ou derivados claros, de petróleo. A rede de dutos em estudo é composta por 14 nós (ou áreas) sendo 4 refinarias, 2 terminais portuários, 2 clientes finais, 5 terminais de distribuição e um entroncamento de válvulas e bombas, interligados por 30 dutos. Nesta rede trafegam mais de 35 derivados claros de petróleo. O processo de programação das atividades de transferência e estocagem envolve restrições operacionais complexas, sendo um problema combinatorial de otimização de difícil resolução. Devido à complexidade do problema, uma estratégia de decomposição é empregada para a modelagem. Esta estratégia tem por base uma divisão hierárquica nos três elementos chaves do scheduling: Alocação dos Recursos, Sequenciamento das Atividades e Determinação Temporal. No presente trabalho aborda-se o módulo de Sequenciamento das Atividades. Desenvolveu-se um modelo PLIM com abordagem temporal contínua que representa o transporte de derivados claros de petróleo por dutos. Objetiva-se obter a ordem de bombeamento das bateladas nas origens, bem como a sequência de passagem pelos dutos da rede, relevando-se gerenciamentos de inventários. Adicionalmente, no contexto do módulo de Sequenciamento, restrições para evitar a necessidade de reversões de fluxo ou inserção de produtos selo devido às incompatibilidades de produtos são modeladas. Testes são realizados usando cenários reais para um horizonte de tempo de, aproximadamente, 30 dias. São apresentados resultados comparativos com um método heurístico e entre versões derivadas do modelo proposto, a fim de investigar o incremento do custo computacional com a inclusão de novas características de modelagem. Os resultados obtidos sugerem a possibilidade de significativa redução do custo operacional com adequado gerenciamento de inventários.This work applies Mixed Integer Linear Programming for a new approach to batch sequencing in a real-world pipeline network. The proposed model is immersed in an optimization framework to aid the operational scheduling of light oil derivatives. The considered pipeline network consists of 14 nodes (areas), with 4 refineries, 2 harbors, 2 final clients, 5 distribution terminals, and a node that links valves and pumps, interconnected by 30 pipelines. In this network, 35 light oil derivatives can be transported. The scheduling process involves complex operational constraints for determining transfer and storage activities, being a combinatorial optimization problem difficult to solve. Due to the complexity of the problem, a decomposition approach is applied for modeling purposes. This strategy is based on a hierarchical division in the three key elements of scheduling: Assignment, Sequencing, and Timing. The Sequencing Module is addressed within this work. It is developed a continuous time MILP model that represents the transportation of light oil derivatives through pipelines. The aim is to obtain the pumping sequencing of batches in the sources, as well as the transportation sequences in pipelines, considering the management of inventories. Additionally, within the sequencing module, constraints to avoid flow reversions or insertion of plug products are modeled. Tests are performed using real scenarios for a time horizon of, approximately, 30 days. Comparative results with a heuristic approach and derived versions of the proposed model are presented in order to investigate the computational cost increase with the addition of new modeling features. The obtained results suggest the possibility of significant operational cost reductions with an adequate management of inventories.
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Delaneze, Marcelo Elias. „Modelagem dinâmica espacial aplicada na avaliação das mudanças da cobertura da terra no entorno de dutos utilizando autômatos celulares : estudo de caso duto ORBEL /“. Rio Claro : [s.n.], 2011. http://hdl.handle.net/11449/92738.
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Orientador: Paulina Setti RiedelBanca: Cláudia Maria de Almeida
Banca: Maria Lúcia Marques
Resumo: A obtenção de informação sobre as condições da rede dutoviária representa papel primordial na operação dos dutos, não só com o propósito de manter a eficiência operacional, mas também, para a minimização dos riscos associados a possíveis acidentes, tanto decorrentes dos processos naturais quanto de causas antrópicas relacionadas ao uso e cobertura da terra. Neste sentido, o emprego de modelos matemáticos em estudos ambientais gera importantes contribuições científicas ao planejamento ordenado de uma área, uma vez que ajudam a entender o impacto das mudanças no uso e cobertura da terra e a prever alterações futuras nos ecossistemas. A área de estudo compreende porções dos municípios de Duque de Caxias, Belford Roxo e Nova Iguaçu e tem por objetivo realizar experimentos de mudanças da cobertura da terra em médio prazo (10 anos) para a faixa de dutos ORBEL. A modelagem realizada neste trabalho foi desenvolvida no software Dinamica-EGO, utilizando como entrada mapas classificados de cobertura da terra, obtidos através de imagens do satélite Landsat 5/TM, e variáveis espaciais para explicar as mudanças ocorridas na cobertura da terra. Para a calibração do modelo, utilizou-se o método de pesos de evidência, disponível no Dinamica-EGO, primeiramente categorizando-se os mapas de variáveis contínuas e, posteriormente, calculando-se os pesos de evidência. Valores positivos favorecem determinada transição, enquanto valores negativos indicam baixa probabilidade de transição, e valores próximos a zero não exercem efeito. A validação do modelo se deu pelo método de similaridade fuzzy, com decaimento exponencial. Os resultados mostram que, para os dois períodos analisados (1987-1998 e 1998-2010), a taxa de mudança para a transição "vegetação arbórea para outros" é bem maior do que para... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Reliable information about conditions of pipeline network represents a major role in the operation of pipelines, not only in order to maintain operational efficiency, but also to minimize the risks associated with possible accidents such as rupture of the ducts due to landslides or mudslides mass block, causing damage to humans and the environment. The use of mathematical models in environmental studies allows significant scientific contributions to the physical planning of an area, since they help to understand the impact of changes in land use and land cover and predict future trends of changes in ecosystems. The study area includes portions of the municipalities of Duque de Caxias, Nova Iguaçu, and Belford Roxo and aims to carry out experiments in land-cover changes in the medium-term (10 years) within the catchment area of ORBEL pipelines. The modeling performed in this work was developed using the software Dinamica-EGO, using as input classified land cover maps obtained from Landsat 5/TM satellite images as well as spatial variables to explain the observed changes in land cover. For the model calibration, we used the method of weights of evidence that is available at Dinamica-EGO. Initially, the maps of continuous variables were categorized according to discrete ranges, which were then employed for the calculation of the respective positive weights of evidence. Positive values foster certain transitions, while negative values indicate low probability of transition, and values close to zero have no effect on changes. Model validation was executed by means of the fuzzy similarity method using exponential decay. The results show that for the two study periods (1987-1998 and 1998-2010) the rate of change for the transition 'others to woody vegetation' is much higher than for the other transitions observed in the same... (Complete abstract click electronic access below)
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