The Experts below are selected from a list of 100692 Experts worldwide ranked by ideXlab platform
Herbert Kopfer - One of the best experts on this subject based on the ideXlab platform.
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request allocation in dynamic collaborative Transportation Planning problems
A Quarterly Journal of Operations Research, 2018Co-Authors: Kristian Schopka, Herbert KopferAbstract:Several publications on collaborative Transportation Planning problems (CTPPs) focus on schemes that ensure a fair assignment of collaborative profits. However, it is seldom taken into account that an even allocation of Transportation resources (e.g. Transportation requests) is also responsible for the viability and stability of horizontal carrier coalitions; particularly if dynamic CTPPs are considered. In this paper, the winner determination problem (WDP) of an auction-based request exchange is restricted by lower and upper bounds that respect an equality between transferred and received requests for carriers. In a computational study, the restricted WDP is applied to the dynamic collaborative traveling salesman problem.
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solving an integrated operational Transportation Planning problem with forwarding limitations
Transportation Research Part E-logistics and Transportation Review, 2016Co-Authors: Mario Ziebuhr, Herbert KopferAbstract:In integrated operational Transportation Planning (IOTP) problems, the traditional vehicle routing problem is extended by using external resources for the fulfillment of Transportation requests. IOTP is getting more complex when the choice of the fulfillment mode is limited for some requests. In this paper, an existing column generation-based heuristic for IOTP is extended by two strategies for handling forwarding limitations. The computational experiments indicate that one of the extended versions of the heuristic outperforms all previous approaches in literature. Further on, the impact of forwarding limitations on different location structures and on the size of the private fleet is analyzed.
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the integrated operational Transportation Planning problem with compulsory requests
International Conference on Computational Logistics, 2014Co-Authors: Mario Ziebuhr, Herbert KopferAbstract:Demand fluctuations and high fixed costs force freight forwarders to consider the integrated operational Transportation Planning problem, which consists in the combined usage of own Transportation resources (self-fulfillment) and external carriers (subcontracting) for the fulfillment of requests. For high quality goods or because of reliability and trustiness, customers prohibit subcontracting for some of their requests (compulsory requests). In this paper we present an approach for solving the integrated problem in case of the existence of compulsory requests. The presented approach is based on an adaptive large neighborhood search and on a column generation procedure. By means of this approach we quantify the increase of fulfillment costs which is caused by different kinds of compulsiveness of Transportation requests. A first benchmark study shows that our heuristic approach for the integrated problem with compulsion outperforms the only approach found in literature for that problem, and therefore justifies the investigation of our main study with 6960 test instances. In our main study more realistic and extended instances are used, which gives us the possibility to consider the impact of different kinds of compulsory requests.
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operational Transportation Planning of freight forwarding companies in horizontal coalitions
European Journal of Operational Research, 2014Co-Authors: Xin Wang, Herbert Kopfer, Michel GendreauAbstract:Abstract In order to improve profitability, freight forwarding companies try to organize their operational Transportation Planning systematically, considering not only their own fleet but also external resources. Such external resources include vehicles from closely related subcontractors in vertical cooperations, autonomous common carriers on the Transportation market, and cooperating partners in horizontal coalitions. In this paper, the Transportation Planning process of forwarders is studied and the benefit of including external resources is analyzed. By introducing subcontracting, the conventional routing of own vehicles is extended to an integrated operational Transportation Planning, which simultaneously constructs fulfillment plans with overall lowest costs using the own fleet and subcontractors’ vehicles. This is then combined with Planning strategies, which intend to increase the profitability by exchanging requests among members in horizontal coalitions. Computational results show considerable cost reductions using the proposed Planning approach.
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Collaborative Transportation Planning of less-than-truckload freight
OR Spectrum, 2014Co-Authors: Xin Wang, Herbert KopferAbstract:Collaborative Transportation Planning (CTP) within a coalition of small and medium-sized freight carriers can be used as a powerful instrument to improve the operational efficiency of the coalition members. In such coalitions, Transportation requests from different carriers are exchanged in order to reduce the total fulfillment costs. In this paper, the CTP for a set of independent carriers exchanging less-than-truckload Transportation requests is considered. The realistic restriction that all collaborating partners have only limited capacities in their fleets is included in the consideration. To keep their autonomy, coalition members keep their sensitive information including customer payments and cost structures unexposed during CTP. A new decentralized request exchange mechanism for CTP is proposed while only vehicle routes are considered for exchange. It is tested on some newly generated instances and the CTP solutions are compared with those obtained by isolated Planning without collaboration and those obtained by a heuristic approach for the centralized Planning problem. The results indicate that our mechanism is very efficient and effective in terms of realizing potential cost-savings by CTP, even when capacity limitations and restrictions on the exposure of information are explicitly considered.
Jarrod Goentzel - One of the best experts on this subject based on the ideXlab platform.
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humanitarian Transportation Planning evaluation of practice based heuristics and recommendations for improvement
European Journal of Operational Research, 2018Co-Authors: Erica Gralla, Jarrod GoentzelAbstract:Abstract Transportation bottlenecks are a common and critical problem in humanitarian response. There is a need for better Planning and prioritization of vehicles to transport humanitarian aid to affected communities. Optimization approaches have been developed for Transportation Planning, but adoption has been limited, due in part to the difficulty of implementation. This paper develops the basis for an easily implementable decision support tool by building on current Planning practices in the humanitarian sector. We draw on an observational study to describe current Planning practices, then develop heuristic algorithms that represent the observed Planning processes, and compare their solutions to each other and to those of a mixed-integer linear program. We identify key weaknesses to guide the development of more sophisticated heuristics or optimization models that fit with current Planning practices. We also find that a simple practice-driven heuristic performs well when it prioritizes deliveries based on destination priority or distance, and we argue that automating such a heuristic in a decision support tool would maintain the simplicity and transparency to enable implementation in practice, and improve Planning by saving time and increasing accuracy and consistency.
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humanitarian Transportation Planning evaluation of practice based heuristics and recommendations for improvement
Social Science Research Network, 2016Co-Authors: Erica Gralla, Jarrod GoentzelAbstract:Transportation bottlenecks are a common and critical problem in humanitarian response. There is a need for better Planning and prioritization of vehicles to transport humanitarian aid to affected communities. Optimization approaches have been developed for Transportation Planning, but adoption has been limited due in part to the difficulty of implementation. This paper develops the basis for an easily implementable decision support tool by identifying the best variations of Planning practices currently in use by the humanitarian sector. We draw on an observational study to describe current Planning practices, then develop heuristic algorithms that represent the observed Planning processes, and compare their solutions to each other and to those of a mixed-integer linear program. We identify key weaknesses that could motivate the adoption of sophisticated Planning tools, but we also find that a simple greedy heuristic performs nearly as well as the mixed-integer program when its prioritization policy allocates vehicles based on the priority of destinations (rather than commodity priorities or distance). Based on these findings, we recommend decision support tools that would maintain the simplicity and transparency to enable implementation in practice, yet improve Planning by saving time and increasing accuracy and consistency.
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problem formulation and solution mechanisms a behavioral study of humanitarian Transportation Planning
Production and Operations Management, 2016Co-Authors: Erica Gralla, Jarrod Goentzel, Charles H FineAbstract:When dealing with urgent, ill-defined problems, such as rapidly evolving emergency situations, operations managers have little time for problem formulation or solution. While the mechanisms by which humans formulate and solve problems have been described, mechanisms for rapid, concurrent formulating and solving are not well understood. This study investigates these mechanisms through a field study of Transportation Planning in a humanitarian response setting. The findings show that the problem is solved through greedy search and formulated through sensemaking, in which search enables updates to an evolving problem formulation, and the formulation directs and limits the search process. This study explores the implications of these findings for the development of better problem formulation processes and problem-solving strategies for urgent and ill-defined operations management problems.
Erica Gralla - One of the best experts on this subject based on the ideXlab platform.
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humanitarian Transportation Planning evaluation of practice based heuristics and recommendations for improvement
European Journal of Operational Research, 2018Co-Authors: Erica Gralla, Jarrod GoentzelAbstract:Abstract Transportation bottlenecks are a common and critical problem in humanitarian response. There is a need for better Planning and prioritization of vehicles to transport humanitarian aid to affected communities. Optimization approaches have been developed for Transportation Planning, but adoption has been limited, due in part to the difficulty of implementation. This paper develops the basis for an easily implementable decision support tool by building on current Planning practices in the humanitarian sector. We draw on an observational study to describe current Planning practices, then develop heuristic algorithms that represent the observed Planning processes, and compare their solutions to each other and to those of a mixed-integer linear program. We identify key weaknesses to guide the development of more sophisticated heuristics or optimization models that fit with current Planning practices. We also find that a simple practice-driven heuristic performs well when it prioritizes deliveries based on destination priority or distance, and we argue that automating such a heuristic in a decision support tool would maintain the simplicity and transparency to enable implementation in practice, and improve Planning by saving time and increasing accuracy and consistency.
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humanitarian Transportation Planning evaluation of practice based heuristics and recommendations for improvement
Social Science Research Network, 2016Co-Authors: Erica Gralla, Jarrod GoentzelAbstract:Transportation bottlenecks are a common and critical problem in humanitarian response. There is a need for better Planning and prioritization of vehicles to transport humanitarian aid to affected communities. Optimization approaches have been developed for Transportation Planning, but adoption has been limited due in part to the difficulty of implementation. This paper develops the basis for an easily implementable decision support tool by identifying the best variations of Planning practices currently in use by the humanitarian sector. We draw on an observational study to describe current Planning practices, then develop heuristic algorithms that represent the observed Planning processes, and compare their solutions to each other and to those of a mixed-integer linear program. We identify key weaknesses that could motivate the adoption of sophisticated Planning tools, but we also find that a simple greedy heuristic performs nearly as well as the mixed-integer program when its prioritization policy allocates vehicles based on the priority of destinations (rather than commodity priorities or distance). Based on these findings, we recommend decision support tools that would maintain the simplicity and transparency to enable implementation in practice, yet improve Planning by saving time and increasing accuracy and consistency.
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problem formulation and solution mechanisms a behavioral study of humanitarian Transportation Planning
Production and Operations Management, 2016Co-Authors: Erica Gralla, Jarrod Goentzel, Charles H FineAbstract:When dealing with urgent, ill-defined problems, such as rapidly evolving emergency situations, operations managers have little time for problem formulation or solution. While the mechanisms by which humans formulate and solve problems have been described, mechanisms for rapid, concurrent formulating and solving are not well understood. This study investigates these mechanisms through a field study of Transportation Planning in a humanitarian response setting. The findings show that the problem is solved through greedy search and formulated through sensemaking, in which search enables updates to an evolving problem formulation, and the formulation directs and limits the search process. This study explores the implications of these findings for the development of better problem formulation processes and problem-solving strategies for urgent and ill-defined operations management problems.
Frank Schultmann - One of the best experts on this subject based on the ideXlab platform.
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decision support system for intermodal freight Transportation Planning an integrated view on transport emissions cost and time sensitivity
A Quarterly Journal of Operations Research, 2017Co-Authors: Andreas Rudi, Konrad Zimmer, Magnus Froehling, Frank SchultmannAbstract:The evaluation and selection of intermodal routes with regard to the key objectives, i.e., transit time, transport emissions and cost, is the main challenge in the design of intermodal networks. The aim of this paper is to present a decision support system for intermodal freight Transportation Planning, which offers methodological contributions to the research on transport mode, route and carrier selection as well as results for industrial practitioners for the assessment of emission abatement potentials. Core of this approach is a capacitated multi-commodity network flow model considering three minimization objectives, i.e. costs, time and CO\(_2\)-equivalents. In this contribution a tri-objective mixed-integer linear model formulation minimizes the number of transported and transshipped full truck loads taking into account tied in-transit capital and the distance travelled. The decision support system is validated in an exemplary case study application analyzing the sensitivity of objectives on optimal route and carrier choice. By applying the augmented \(\varepsilon \)-constraint method, a Pareto-efficient frontier is determined to investigate the tradeoff between economic and ecological objectives in intermodal freight Transportation Planning.
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Freight Transportation Planning considering carbon emissions and in-transit holding costs: a capacitated multi-commodity network flow model
EURO Journal on Transportation and Logistics, 2016Co-Authors: Andreas Rudi, Konrad Zimmer, Magnus Fröhling, Frank SchultmannAbstract:To mitigate climate relevant air emissions from freight Transportation, policy makers stimulate the application of intermodal freight transport chains. The evaluation and selection of intermodal routes based on the key objectives, i.e., greenhouse gas emission, Transportation cost and transit time improvements, are the main challenges in the design of intermodal networks. It is the aim of this paper to provide decision support in intermodal freight Transportation Planning concerning route and carrier choice in transport service design and the assessment of emission abatement potentials. Core of this approach is a capacitated multi-commodity network flow model considering multiple criteria and in-transit inventory. Thereby two processes are modeled, i.e., the transport and transshipment of full truckloads (FTL), to define the material flow of goods through the network. The objective function of the developed network flow model minimizes the number of transported and transshipped FTL assessed by the weighted and normalized criteria (i.e., CO_2-equivalents, cost, time) taking into account tied in-transit capital and the distance traveled. Thereby, the model regards carrier and terminal capacities, the option to transfer or either shift the mode and/or change the carrier at predefined terminal transshipment points. The model is incorporated in a decision support system and applied in an example application with industry data from an automotive supplier to demonstrate its application potentials. Within the application among others the potential benefits of the developed optimization model in comparison to a status quo are analyzed. Different criteria weightings and the influence of various levels of in-transit holding costs are investigated. In addition, the introduction of new Transportation means such as the Eurocombi is assessed.
Andreas Rudi - One of the best experts on this subject based on the ideXlab platform.
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decision support system for intermodal freight Transportation Planning an integrated view on transport emissions cost and time sensitivity
A Quarterly Journal of Operations Research, 2017Co-Authors: Andreas Rudi, Konrad Zimmer, Magnus Froehling, Frank SchultmannAbstract:The evaluation and selection of intermodal routes with regard to the key objectives, i.e., transit time, transport emissions and cost, is the main challenge in the design of intermodal networks. The aim of this paper is to present a decision support system for intermodal freight Transportation Planning, which offers methodological contributions to the research on transport mode, route and carrier selection as well as results for industrial practitioners for the assessment of emission abatement potentials. Core of this approach is a capacitated multi-commodity network flow model considering three minimization objectives, i.e. costs, time and CO\(_2\)-equivalents. In this contribution a tri-objective mixed-integer linear model formulation minimizes the number of transported and transshipped full truck loads taking into account tied in-transit capital and the distance travelled. The decision support system is validated in an exemplary case study application analyzing the sensitivity of objectives on optimal route and carrier choice. By applying the augmented \(\varepsilon \)-constraint method, a Pareto-efficient frontier is determined to investigate the tradeoff between economic and ecological objectives in intermodal freight Transportation Planning.
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Freight Transportation Planning considering carbon emissions and in-transit holding costs: a capacitated multi-commodity network flow model
EURO Journal on Transportation and Logistics, 2016Co-Authors: Andreas Rudi, Konrad Zimmer, Magnus Fröhling, Frank SchultmannAbstract:To mitigate climate relevant air emissions from freight Transportation, policy makers stimulate the application of intermodal freight transport chains. The evaluation and selection of intermodal routes based on the key objectives, i.e., greenhouse gas emission, Transportation cost and transit time improvements, are the main challenges in the design of intermodal networks. It is the aim of this paper to provide decision support in intermodal freight Transportation Planning concerning route and carrier choice in transport service design and the assessment of emission abatement potentials. Core of this approach is a capacitated multi-commodity network flow model considering multiple criteria and in-transit inventory. Thereby two processes are modeled, i.e., the transport and transshipment of full truckloads (FTL), to define the material flow of goods through the network. The objective function of the developed network flow model minimizes the number of transported and transshipped FTL assessed by the weighted and normalized criteria (i.e., CO_2-equivalents, cost, time) taking into account tied in-transit capital and the distance traveled. Thereby, the model regards carrier and terminal capacities, the option to transfer or either shift the mode and/or change the carrier at predefined terminal transshipment points. The model is incorporated in a decision support system and applied in an example application with industry data from an automotive supplier to demonstrate its application potentials. Within the application among others the potential benefits of the developed optimization model in comparison to a status quo are analyzed. Different criteria weightings and the influence of various levels of in-transit holding costs are investigated. In addition, the introduction of new Transportation means such as the Eurocombi is assessed.
