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  • 1.
    Bakhtyar, Shoaib
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Holmgren, Johan
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    A Data Mining Based Method for Route and Freight Estimation2015In: Procedia Computer Science, Elsevier, 2015, Vol. 52, p. 396-403Conference paper (Refereed)
    Abstract [en]

    We present a method, which makes use of historical vehicle data and current vehicle observations in order to estimate 1) the route a vehicle has used and 2) the freight the vehicle carried along the estimated route. The method includes a learning phase and an estimation phase. In the learning phase, historical data about the movement of a vehicle and of the consignments allocated to the vehicle are used in order to build estimation models: one for route choice and one for freight allocation. In the estimation phase, the generated estimation models are used together with a sequence of observed positions for the vehicle as input in order to generate route and freight estimates. We have partly evaluated our method in an experimental study involving a medium-size Swedish transport operator. The results of the study indicate that supervised learning, in particular the algorithm Naive Bayes Multinomial Updatable, shows good route estimation performance even when significant amount of information about where the vehicle has traveled is missing. For the freight estimation, we used a method based on averaging the consignments on the historical known trips for the estimated route. We argue that the proposed method might contribute to building improved knowledge, e.g., in national road administrations, on the movement of trucks and freight.

  • 2.
    Bakhtyar, Shoaib
    et al.
    Blekinge Institute of Technology, School of Computing.
    Holmgren, Johan
    Blekinge Institute of Technology, School of Computing.
    Persson, Jan
    Blekinge Institute of Technology, School of Computing.
    A synergy based method for designing ITS services2013In: international Journal of Advanced Logistics, ISSN 2287-7592, Vol. 2, no 2, p. 45-54Article in journal (Refereed)
    Abstract [en]

    In this paper, we propose a method for supporting the process of designing Intelligent Transportation System (ITS) services, which utilizes on primarily functional synergies with already existing services. Using synergies between services will enable sharing of resources, such as, information entities, functions and technical resources, which in turn may lead to reduced costs for implementing services. The method is built around an existing service description framework, which is used to describe both existing services and the service to be designed. In order to illustrate the usage of the suggested method, we have applied it for designing a new ITS service, i.e., the Liability Intelligent Transport System (LITS) service. The purpose of the LITS service is to support the process of identifying when, where and why freight has been damaged, and which actor was responsible when the freight was damaged. The LITS service may lead to better quality control of consignments and may also facilitate the identification of which actor was responsible for the freight damage, which is of particular interest in multi-modal transport. By applying our service design method we were able to identify that three out of four functions of the LITS service already exist in other existing ITS services. Therefore, the LITS service can be designed based on synergies with these services.

  • 3.
    Bakhtyar, Shoaib
    et al.
    Blekinge Institute of Technology, School of Computing.
    Holmgren, Johan
    Blekinge Institute of Technology, School of Computing.
    Persson, Jan
    Analysis of information synergy between e-Waybill solutions and intelligent transport system services2013In: World Review of Intermodal Transportation Research (WRITR), ISSN 1749-4729, E-ISSN 1749-4737, Vol. 4, no 2-3, p. 123-139Article in journal (Refereed)
    Abstract [en]

    We present a study on information synergy between an electronic waybill (e-Waybill) and intelligent transportation system (ITS) services. A waybill is an important transport document, and it contains essential information about a consignment. We consider five e-Waybill solutions, which differ in where the e-Waybill information is stored, read, and written. We analyse 20 ITS services, and for each of them, the required input entities that can be provided by an e-Waybill are identified, and the synergy with each of the e-Waybill solutions is determined based on the location of the e-Waybill information. The analysis shows that e-Waybill solutions with storage at the freight-level enable the highest information synergy with ITS services. Our result may support the implementation of practical e-Waybill systems that provide high synergy with ITS services, which may lead to higher utilisation of ITS services and more sustainable transport, e.g., in terms of reduced congestion and emissions

  • 4.
    Bakhtyar, Shoaib
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Holmgren, Johan
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Persson, Jan A.
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Technical Requirements of the e-Waybill Service2016In: International Journal of Computer and Communication Engineering, ISSN 2010-3743, ISSN 2010-3743, Vol. 5, no 2, p. 130-140Article in journal (Refereed)
    Abstract [en]

    An electronic waybill (e-Waybill) is a service whose purpose is to replace the paper waybill, which is a paper documents that traditionally follows a consignment during transport. An important purpose of the e-Waybill is to achieve a paperless flow of information during freight transport. In this paper, we investigate five e-Waybill solutions, that is, system design specifications for the e-Waybill, regarding their non-functional (technical) requirements. In addition, we discuss how well existing technologies are able to fulfil the identified requirements. We have identified that information storage, synchronization and conflict management, access control, and communication are important categories of technical requirements of the e-Waybill service. We argue that the identified technical requirements can be used to support the process of designing and implementing the e-Waybill service.

  • 5. Bakhtyar, Shoaib
    et al.
    Persson, Jan A.
    Holmgren, Johan
    Achieving services when turning a waybill into an e-waybill2011Conference paper (Refereed)
    Abstract [en]

    The focus of this paper is to present potential electronic waybill (e-waybill) solutions for a traditional waybill with the potential for supporting different Intelligent Transport System (ITS) services, such as, identification of freight, automating the exchange of content-related data for regulatory or commercial purposes, etc. At present there are some initiatives, for instance, by the International Air Transport Association (IATA) and the e-Freight framework, for achieving solutions that can handle e-waybills. Both these solutions focus on actor-to-actor communication, however we hypothesize that the storage of a waybill’s data both locally and centrally (i.e. actor-to-actor as well as goods-to-actor communication) can support more services than only central storage of the waybill’s data. Further we look at the information required and possible communication links between different actors in order to identify different ITS services that can be achieved through an e-waybill solution. We then map this information on to the e-waybill solutions that we have proposed, which will allow us to identify which services are supported by the different e-waybill solutions.

  • 6.
    Davidsson, Paul
    et al.
    Blekinge Institute of Technology, School of Computing.
    Gustafsson Friberger, Marie
    Holmgren, Johan
    Blekinge Institute of Technology, School of Computing.
    Jacobsson, Andreas
    Persson, Jan A.
    Agreement Technologies for Supporting the Planning and Execution of Transports2013In: Agreement Technologies, Law, Governance and Technology Series / [ed] Ossowski, Sascha, Dordrecht: Springer Netherlands , 2013, p. 533-547Chapter in book (Refereed)
    Abstract [en]

    The use of agreement technologies in the planning and execution of goods transports is analyzed. We have previously suggested an approach called Plug and Play Transport Chain Management (PnP TCM) that provides agent-based support for key tasks, such as, finding the best sequence of transport services for a particular goods transport, monitoring the execution of the transport, and managing the interaction between the involved actors. In this paper we analyze five agreement technologies in the context of PnP TCM, i.e., semantics, norms, organizations, argumentation and negotiation, and trust. We conclude that all five technologies play a critical role in the realization of PnP TCM.

  • 7. Davidsson, Paul
    et al.
    Holmgren, Johan
    Kyhlbäck, Hans
    Mengistu, Dawit
    Persson, Marie
    Applications of Agent Based Simulation2007Conference paper (Refereed)
    Abstract [en]

    This paper provides a survey and analysis of applications of Agent Based Simulation (ABS). A framework for describing and assessing the applications is presented and systematically applied. A general conclusion from the study is that even if ABS seems a promising approach to many problems involving simulation of complex systems of interacting entities, it seems as the full potential of the agent concept and previous research and development within ABS often is not utilized. We illustrate this by providing some concrete examples. Another conclusion is that important information of the applications, in particular concerning the implementation of the simulator, was missing in many papers. As an attempt to encourage improvements we provide some guidelines for writing ABS application papers.

  • 8. Davidsson, Paul
    et al.
    Holmgren, Johan
    Persson, Jan A.
    Jacobsson, Andreas
    Plug and Play Transport Chain Management: Agent-Based Support to the Planning and Execution of Transports2011In: e-Business and Telecommunications, Communications in Computer and Information Science / [ed] Obaidat, Mohammad S.; Filipe, Joaquim, Berlin Heidelberg: Springer , 2011, p. 139-155Chapter in book (Refereed)
    Abstract [en]

    A novel approach to efficiently plan and execute effective transport solutions is presented. It provides agent-based support for key tasks, such as, finding the best sequence of transport services for a particular goods transport, monitoring the execution of the transport, as well as the interaction between the involved actors. The approach is based on the FREIGHTWISE framework in which a minimal set of information packages is defined. The purpose is to capture all the information that needs to be communicated between the actors involved in a transport, such as, transport users, transport providers, and infrastructure managers, during the complete process from planning to termination. The approach is inspired by the concepts of virtual enterprises and breeding environments. We analyse the requirements of such an approach and describe a multi-agent system architecture meeting these requirements.

  • 9.
    Davidsson, Paul
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Holmgren, Johan
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Persson, Jan A.
    Ramstedt, Linda
    Multi Agent Based Simulation of Transport Chains2008Conference paper (Refereed)
    Abstract [en]

    An agent-based tool for micro-level simulation of transport chains (TAPAS) is described. It is more powerful than traditional approaches as it is able to capture the interactions between individual actors of a transport chain, as well as their heterogeneity and decision making processes. Whereas traditional approaches rely on assumed statistical correlation between different parameters, TAPAS relies on causality, i.e., the decisions and negotiations that lead to the transports being performed. An additional advantage is that TAPAS is able to capture time aspects, such as, the influence of timetables, arrival times, and time-differentiated taxes and fees. TAPAS is composed of two layers, one layer simulating the physical activities taking place in the transport chain, e.g., production, storage, and transports of goods, and another layer simulating the different actors’ decision making processes and interaction. The decision layer is implemented as a multi-agent system using the JADE platform, where each agent corresponds to a particular actor. We demonstrate the use of TAPAS by investigating how the actors in a transport chain are expected to act when different types of governmental control policies are applied, such as, fuel taxes, road tolls, and vehicle taxes. By analyzing the costs and environmental effects, TAPAS provides guidance in decision making regarding such control policies. We argue that TAPAS may also complement existing approaches in different ways, for instance by generating input data such as transport demand. Since TAPAS models a larger part of the supply chain, the transport demand is a natural part of the output. Studies may concern operational decisions like choice of consignment size and frequency of deliveries, as well as strategic decisions like where to locate storages, terminals, etc., choice of producer, and adaptation of vehicle fleets.

  • 10. Davidsson, Paul
    et al.
    Persson, Jan A.
    Holmgren, Johan
    On the Integration of Agent-Based and Mathematical Optimization Techniques2007In: 1st KES International Symposium on Agent and Multi-Agent Systems: Technologies, SPRINGER-VERLAG BERLIN , 2007, p. 1-10Chapter in book (Refereed)
    Abstract [en]

    The strengths and weaknesses of agent-based approaches and classical optimization techniques are compared. Their appropriateness for resource allocation problems were resources are distributed and demand is changing is evaluated. We conclude that their properties are complementary and that it seems beneficial to combine the approaches. Some suggestions of such hybrid systems are sketched and two of these are implemented and evaluated in a case study and compared to pure agent and optimization-based solutions. The case study concerns allocation of production and transportation resources in a supply chain. In one of the hybrid systems, optimization techniques were embedded in the agents to improve their decision making capability. In the other system, optimization was used for creating a long-term coarse plan which served as input the agents that adapted it dynamically. The results from the case study indicate that it is possible to capitalize both on the ability of agents to dynamically adapt to changes and on the ability of optimization techniques for finding high quality solutions.

  • 11. Holmgren, Johan
    Multi-Agent-Based Simulation and Optimization of Production and Transportation2008Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis addresses the integration of software agent technology, simulation and mathematical optimization within the domain of production and transportation. It has been argued that agentbased approaches and mathematical optimization can complement each other in the studied domain. These technologies have often been used separately, but the existing amount of literature concerning how to combine them is rather limited, especially in the domain of production and transportation. This domain is considered complex since; for instance, the decision making is characterized by many decision makers that are influencing each other. Also, problems in the domain are typically large and combinatorial. The transportation of goods has both positive and negative effects on society. A positive effect is the possibility for people to consume products that have been produced at distant locations. Examples of negative effects are: emissions, congestion, accidents, and large costs for infrastructure investments. Increasing competition, experienced by manufacturers and haulers, acts as a motivation for improving the utilization of often limited and expensive production and transportation resources. It is important to maximize the positive effects of transportation while the negative effects are minimized. We present a rather general agent-based simulator (TAPAS) for simulation of production and transportation. By using agent technology, we have been able to simulate the decision making and interaction between decision makers, which is difficult using traditional simulation techniques. We provide a technical description of how TAPAS was modeled, and examples of how it can be used. An optimization model for a real world ``Integrated Production, Inventory, and Distribution Routing Problem’’ (IPIDRP) has been developed. The identified IPIDRP is in the domain of production and transportation problems. For solving and analyzing the problem, we developed a solution method based on the principles of Dantzig- Wolfe decomposition, which was implemented as a multi-agent system inside TAPAS. The purpose is to improve resource utilization and to analyze the potential effects of introducing VMI (Vendor Managed Inventory). Experiments are performed for quantifying the benefits of VMI and for estimating the effects of an agentification of the decomposition approach. Some advantages and disadvantages of an agentification are discussed in this thesis. The work indicates high potentials for integrating agent technology and mathematical optimization. One direction for future work is to use TAPAS as a tool for evaluating the results that are produced by the optimization algorithm. For real world systems, evaluation of optimization results can be expensive and difficult to carry out, and we believe that simulation can be useful for evaluation purposes.

  • 12. Holmgren, Johan
    On the integration of optimization and agent technology for transportation and production planning2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis concerns the integration of agent technology and mathematical optimization for improved decision support within the domain of analysis and planning of production and transportation. These two approaches have often been used separately in this domain but the research concerning how to combine them is very limited. The studied domain is considered to be complex due to the fact that many decision makers, which influence each other, often are involved in the decision making process. Moreover, problems in the domain are typically large and combinatorial, which makes them more difficult to solve. We argue that the integration of agent-based approaches and mathematical optimization has a high potential to improve analysis and planning of production and transportation. In order to support this hypothesis, we have developed and analyzed three different approaches to the integration of agent technology and mathematical optimization. First, we present a Multi-Agent-Based Simulation (MABS) model called TAPAS for simulation of decision-making and physical activities in supply chains. By using agent technology and optimization, we were able to simulate the decision-making of the involved actors as well as the interaction between them, which is difficult using traditional simulation techniques. In simulation experiments, TAPAS has been used to study the effects of different types of governmental taxes, and synchronization of timetables. Moreover, we provide an analysis of existing MABS applications with respect to a number of criteria. Also, we present a framework containing a number of abstract roles, responsibilities, and interactions, which can be used to simplify the process of developing MABS models. Second, we present an approach for efficient planning and execution of intermodal transports. The approach provides agent-based support for key tasks, such as, finding the optimal sequence of transport services (potentially provided by different transport operators) for a particular goods transport, and monitoring the execution of transports. We analyzed the requirements of such an approach and described a multi-agent system architecture meeting these requirements. Finally, an optimization model for a real world integrated production, inventory, and routing problem was developed. For solving and analyzing the problem, we developed an agent-based solution method based on the principles of Dantzig-Wolfe decomposition. The purpose was to improve resource utilization and to analyze the potential effects of introducing VMI (Vendor Managed Inventory). In a case study, we conducted simulation experiments, which indicated that an increased number of VMI customers may give a significant reduction of the total cost in the system.

  • 13. Holmgren, Johan
    et al.
    A.Persson, Jan
    Davidsson, Paul
    Agent-Based Dantzig-Wolfe Decomposition2009Conference paper (Refereed)
    Abstract [en]

    We present an agent-based approach to Dantzig-Wolfe column generation (a decomposition approach), which is applied to an integrated production, inventory, and distribution routing optimization problem. The decomposition model has been implemented in the Java programming language, using the Java Agent DEvelopment Framework (JADE) and the ILOG CPLEX mixed integer linear optimization problem solver. The model has been validated oil a set of realistic scenarios and based on the results, we estimate the potential performance improvement which can be obtained by using a completely distributed implementation. We analyze the overhead, in terms of communication costs, that is imposed by an agent-based approach.

  • 14.
    Holmgren, Johan
    et al.
    Blekinge Institute of Technology, School of Computing.
    Dahl, Mattias
    Blekinge Institute of Technology, School of Engineering, Department of Mathematics and Natural Sciences.
    Davidsson, Paul
    Person, Jan A.
    Agent-based simulation of freight transport between geographical zones2013Conference paper (Refereed)
    Abstract [en]

    We present TAPAS-Z, which is an agent-based freight transport analysis model for simulation of decision-making and transport activities. TAPAS-Z is a further development of a simulation model called TAPAS, and it has improved support for simulation of transport in large geographical regions. It is based on the principles that shipments are simulated for chosen supplier-consumer relations in a geographic region, and that the geographic locations of suppliers and consumers are randomly varied for each shipment. In TAPAS-Z, one supplier represents all real-world suppliers in a geographic zone, and one consumer represents all real-world consumers in a zone. In that way, TAPAS-Z is able to capture some of the diversity in freight transport that is caused by the varying geographic locations of senders and receivers, and which is important when assessing the impact of transport policy and infrastructural measures.

  • 15. Holmgren, Johan
    et al.
    Davidsson, Paul
    Persson, Jan A.
    Ramstedt, Linda
    An Agent Based Simulator for Production and Transportation of Products2007Conference paper (Refereed)
  • 16.
    Holmgren, Johan
    et al.
    Blekinge Institute of Technology, School of Computing.
    Davidsson, Paul
    Persson, Jan A.
    Ramstedt, Linda
    TAPAS: A multi-agent-based model for simulation of transport chains2012In: Simulation (San Diego, Calif.), ISSN 1569-190X, E-ISSN 1878-1462, Vol. 23, p. 1-18Article in journal (Refereed)
    Abstract [en]

    We present the Transportation And Production Agent-based Simulator (TAPAS), which is an agent-based model for simulation of transport chains that can be used, e.g., for analysis of transport-related policy and infrastructure measures. TAPAS is more powerful than traditional approaches to freight transport analysis, as it explicitly models production and customer demand, and it captures the interaction between individual transport chain actors, their heterogeneity and decision making processes, as well as time aspects. Whereas traditional approaches rely on assumed statistical correlation, TAPAS relies on causality, i.e., the focus is on the decisions and negotiations that lead to activities. TAPAS is composed of two connected layers, one that simulates the physical activities, e.g., production and transportation, and one that simulates the decision making and interaction between actors. We illustrate TAPAS with a scenario in which the consequences of three transport policy and infrastructure measures are studied.

  • 17.
    Holmgren, Johan
    et al.
    Blekinge Institute of Technology, School of Computing.
    Lindberg, Per Olov
    Upright Stiff: subproblem updating in the FW method for traffic assignment2014In: EURO Journal on Transportation and Logistics, ISSN 2192-4384 , Vol. 3, no 3, p. 205-225Article in journal (Refereed)
    Abstract [en]

    We present improvements of the Frank–Wolfe (FW) method for static vehicular traffic and telecom routing. The FW method has been the dominating method for these problem types, but due to its slow asymptotic convergence it has been considered dead by methods oriented researchers. However, the recent introduction of conjugate FW methods has shown that it is still viable, and in fact the winner on multi-core computers. In this paper, we show how to speed up the FW iterations, by updating the subproblems in the FW method, instead of solving them from scratch. The subproblem updating is achieved by viewing the subproblems as network flow problems with a threaded representation of the shortest path trees. In addition, we introduce a new technique, thread following, implying that a single traversal of the thread is enough to find a new shortest path tree. Our computational tests show that very few nodes in practice are visited more than once when searching for improving arcs. Moreover, we update also the all-or-nothing solutions of the subproblems, resulting in significantly reduced loading times. For a set of standard test problems, we observe speedups in the region of 25–50% for the subproblem updating FW method, compared to the traditional non-updating version. We typically achieve higher speedups for more difficult problems and converged solutions.

  • 18.
    Holmgren, Johan
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Nikopoulou, Zoi
    Ramstedt, Linda
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Woxenius, Johan
    Modelling modal choice effects of regulation on low-sulphur marine fuels in Northern Europe2014In: Transportation Research Part D: Transport and Environment, ISSN 1361-9209, E-ISSN 1879-2340, Vol. 28, no S1, p. 62-73Article in journal (Refereed)
    Abstract [en]

    The implementation of MARPOL Annex VI in the North and Baltic Sea Sulphur Emission Control Area (SECA) has raised economic concerns among shippers and shipowners, as well as spurred policymakers to appeal to various interests, such as citizen health, export industry competitiveness, and consumer prices. To justify their cases, policymakers and stakeholders have commissioned various agencies to monitor the implementation’s effects upon sustainability, especially regarding a potential modal shift from sea to road transport. This article thus reviews some of these commissioned studies in order to analyse the effects of the implementation and the possibility of modal shift. It also provides an agent-based simulation study of route choice for comparatively high-value cargo from Lithuania in the east to the United Kingdom in the west. Ultimately, the results of our TAPAS study do not provide concrete evidence supporting a modal shift from sea to road transport and indeed, they indicate that a shift is unlikely to occur.

  • 19.
    Holmgren, Johan
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Systems and Software Engineering.
    Persson, Jan A.
    Blekinge Institute of Technology, School of Engineering, Department of Systems and Software Engineering.
    Davidsson, Paul
    Blekinge Institute of Technology, School of Engineering, Department of Systems and Software Engineering.
    Agent Based Decomposition of Optimization Problems2008Conference paper (Refereed)
    Abstract [en]

    In this paper, we present an agent-based approach for solving an optimization problem using a Dantzig-Wolfe column generation scheme, i.e., a decomposition approach. It has been implemented and tested on an integrated production, inventory, and distribution routing problem. We developed a decomposition model for this optimization problem, which was implemented in the Java programming language, using the Java Agent DEvelopment Framework (JADE) and the ILOG CPLEX mixed integer linear problem solver. The model was validated on a realistic scenario and based on the results, we present estimates of the potential performance gain by using a completely distributed implementation. We also analyze the overhead, in terms of communication costs, imposed by an agent based approach. Further we discuss the advantages and the disadvantages that comes with an agent-based decomposition approach.

  • 20. Holmgren, Johan
    et al.
    Persson, Jan A.
    Davidsson, Paul
    Agent-Based Dantzig-Wolfe Decomposition2009In: Agent and Multi-Agent Systems: Technologies and Applications Third KES International Symposium, KES-AMSTA 2009, Uppsala, Sweden, June 3-5, 2009, Proceedings / [ed] al., A. Håkansson et, Berlin Heidelberg: Springer-Verlag , 2009, p. 754-763Chapter in book (Refereed)
    Abstract [en]

    We present an agent-based approach to Dantzig-Wolfe column generation (a decomposition approach), which is applied to an integrated production, inventory, and distribution routing optimization problem. The decomposition model has been implemented in the Java programming language, using the Java Agent DEvelopment Framework (JADE) and the ILOG CPLEX mixed integer linear optimization problem solver. The model has been validated on a set of realistic scenarios and based on the results, we estimate the potential performance improvement which can be obtained by using a completely distributed implementation. We analyze the overhead, in terms of communication costs, that is imposed by an agent-based approach.

  • 21.
    Holmgren, Johan
    et al.
    Blekinge Institute of Technology, School of Computing.
    Persson, Jan A.
    Blekinge Institute of Technology, School of Computing.
    Davidsson, Paul
    Blekinge Institute of Technology, School of Computing.
    Improving Multi-actor Production, Inventory and Transportation Planning through Agent-Based Optimization2013In: Agent and Multi-Agent Systems in Distributed Systems: Digital Economy and E-Commerce, Studies in Computational Intelligence / [ed] Hakansson, Anne; Hartung, Ronald, Berlin Heidelberg: Springer-Verlag , 2013, p. 1-31Chapter in book (Refereed)
    Abstract [en]

    We present an agent-based optimization approach that is built upon the principles of Dantzig-Wolfe column generation, which is a classic reformulation technique. We show how the approach can be used to optimize production, inventory, and transportation, which may result in improved planning for the involved supply chain actors. An important advantage is the possibility to keep information locally when possible, while still enabling global optimization of supply chain activities. In particular, the approach can be used as strategic decision support to show how the involved actors may benefit from applying Vendor Managed Inventory (VMI). In a case study, the approach has been applied to a real-world integrated production, inventory and routing problem, and the results from our experiments indicate that an increased number of VMI customers may give a significant reduction of the total cost in the system. Moreover, we analyze the communication overhead that is caused by using an agent-based, rather than a traditional (non agent-based) approach to decomposition, and some advantages and disadvantages are discussed.

  • 22.
    Holmgren, Johan
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Ramstedt, Linda
    Davidsson, Paul
    A study on quantitative freight transport analysis models in Denmark and Sweden2014Conference paper (Refereed)
    Abstract [en]

    Purpose The aim of this paper is to present a study on freight transport analysis models. The purpose is to identify different stakeholders’ perceptions of existing models, e.g., strengths and weaknesses, and of their requirements and views on future models. Design/methodology/approach The study is based on a questionnaire and interviews with representatives of public authorities, consultancy companies, and universities in Sweden and Denmark. Findings The study shows that there is a need for freight analysis models for supporting the transport planning in public authorities, including impact assessment of actions and estimation of freight flows. The respondents work mainly with macro-level models, whose main strength is their large geographic scopes, which allow comparative studies on, e.g., the national level using one model. Weaknesses include poor quality, missing functionality, and inadequate user-friendliness. In order to achieve improved freight transport analysis, the respondents wish to include more detailed logistics aspects in their analyses, which could possibly be achieved by combining macro-level and agent-based models. Research limitations/implications The limitation of this study is that we only included Danish and Swedish respondents, who mainly work with macro-level models. Moreover, only one Danish person answered the questionnaire. However, the respondent group represent a wide knowledge on freight and passenger transport models, and the study concerns to a large extent model types, not only particular models. Therefore, we argue that our findings have a wider geographic applicability. Practical implications The outcome of our study might be used by researchers and public authorities in order to, e.g., guide the decision-making on future model development: the views of the model users and clients are important to consider in order to assure that the development and research efforts lead to fulfilling their needs. Original/value The presented work provides insight into the needs and attitudes of model users and clients involved in freight transport analysis. This knowledge is important, e.g., for researchers involved in model development. According to the best of our knowledge, there is no previous study like the one presented.

  • 23. Holmgren, Johan
    et al.
    Ramstedt, Linda
    Davidsson, Paul
    Roles and responsibilities in supply chains An agent simulation modeling framework2010Conference paper (Refereed)
    Abstract [en]

    To predict which supply chain effects will appear when applying governmental control policies, infrastructure investments, and business strategies, multi-agent-based simulation (MABS) can be used. In this paper, we identify abstract supply chain responsibilities, roles and interactions that are argued to be sufficient for representing all types of organizations involved in the processes of buying and selling products and transport services. The identified responsibilities, roles and interactions are organized into a framework together with a set of modeling guidelines, which we relate to the GAIA methodology to simplify the process of developing multi-agent-based supply chain simulation models. To illustrate the usage of the framework, we provide two case studies where we apply it to two different MABS models.

  • 24. Holmgren, Johan
    et al.
    Ramstedt, Linda
    Davidsson, Paul
    Roles and responsibilities in transport chains: Agent simulation modeling challenges2009Conference paper (Refereed)
    Abstract [en]

    When applying transport policies or business strategies to a trans- portation system, different effects, such as environmental and economic effects, typically appear. Simulation can be used to predict such effects for a given pol- icy or strategy, and we argue that to fully capture such effects there is a need to model the underlying decisions and actions in the transport chain. The aim of this paper is to identify and discuss some important transport chain responsibilities and roles that need to be captured in a simulation model in order to study these types of effects. The roles concern basic functionality related to using and providing services, and the responsibilities include decisions and actions that concern ordering of products and transports, and planning of how to use resources and infrastructure. We contribute with a framework, which on an abstract level describes responsibilities, roles and interactions that are important to consider in an agent-based transport chain simulation model. We argue that our framework can be used as assistance when developing an agent-based transport simulation model. To illustrate how the framework can be realized, we briefly describe an agent-based simulation tool called TAPAS.

  • 25.
    Holmgren, Johan
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Ramstedt, Linda
    Davidsson, Paul
    Edwards, Henrik
    Persson, Jan A.
    Combining macro-level and agent-based modeling for improved freight transport analysis2014In: Procedia Computer Science, Elsevier , 2014, Vol. 32, p. 380-387Conference paper (Refereed)
    Abstract [en]

    Macro-level models is the dominating type of freight transport analysis models for supporting the decision-making in public authorities. Recently, also agent-based models have been used for this purpose. These two model types have complementing characteristics: macro-level models enable to study large geographic regions in low level of detail, whereas agent-based models enable to study entities in high level of detail, but typically in smaller regions. In this paper, we suggest and discuss three approaches for combining macro-level and agent-based modeling: exchanging data between models, conducting supplementary sub-studies, and integrating macro-level and agent-based modeling. We partly evaluate these approaches using two case studies and by elaborating on existing freight transport analysis approaches based on executing models in sequence.

  • 26.
    Holmgren, Johan
    et al.
    Blekinge Institute of Technology, School of Computing.
    Ramstedt, Linda
    Davidsson, Paul
    Persson, Jan A.
    Multi-Agent-Based Simulation for Analysis of Transport Policy and Infrastructure Measures2012Conference paper (Refereed)
    Abstract [en]

    In this paper we elaborate on the usage of multi-agent-based simulation (MABS) for quantitative impact assessment of transport policy and infrastructure measures. We provide a general discussion on how to use MABS for freight transport analysis, focusing on issues related to input data management, validation and verification, calibration, output data analysis, and generalization of results. The discussion is built around an agent-based transport chain simulation tool called TAPAS (Transportation And Production Agent-based Simulator) and a simulation study concerning a transport chain around the Southern Baltic Sea.

  • 27.
    Mbiydzenyuy, Gideon
    et al.
    Blekinge Institute of Technology, School of Computing.
    Dahl, Mattias
    Blekinge Institute of Technology, School of Engineering, Department of Mathematics and Natural Sciences.
    Holmgren, Johan
    Blekinge Institute of Technology, School of Computing.
    Road travel time prediction: A micro-level sampling approach2013Conference paper (Refereed)
    Abstract [en]

    The ability to generate accurate travel time predictions for road freight transport is important when, for example, estimating the arrival times for heavy goods vehicles (HGVs) in order to plan terminal activities. We present a micro-level sampling method for road travel time prediction. The method makes use of historical GPS-data in order to determine the movement of a vehicle from an origin to a destination along a specific route. The method generates a travel time distribution, which can be used to obtain the expected travel time and probabilities for deviations. The method has been illustrated and evaluated in an experiment where the effective travel time was predicted for transport between two terminals. The experiment made use of GPS data that was recorded for two HGVs during a period of two months. An important feature of the method is that it does not need road network information, such as speed limits and number of lanes.

  • 28. Ramstedt, Linda
    et al.
    Davidsson, Paul
    Holmgren, Johan
    Persson, Jan A.
    On the Use of Micro-level Simulation for Estimation of the Effects of Governmental Control Policies2007Conference paper (Refereed)
  • 29.
    Sigakova, Ksenia
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Mbiydzenyuy, Gideon
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Holmgren, Johan
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Impacts of traffic conditions on the performance of road freight transport2015In: 2015 IEEE 18TH INTERNATIONAL CONFERENCE ON INTELLIGENT TRANSPORTATION SYSTEMS, 2015, p. 2947-2952Conference paper (Refereed)
    Abstract [en]

    The efficiency of road transport is typically influenced by factors such as, weather, choice of road, and time of day, and day of the week. Knowledge about interactions between different traffic-and transport related factors and their influence on the execution of transport is important in transport planning. The purpose of this paper is to study the impact of different factors on the performance of road transport. We aim to contribute to improved transport planning by analysing traffic and transport data obtained from different sources in order to support data driven decision making. Through a review of existing literature and discussions with a Swedish road transport operator, we identified factors that could be relevant to consider when planning a transport, e.g., related to weather, location of roads where the transport will take place, and planned time of the transport. As a result of variation in size, type and volume of the data representing these factors, suitable machine learning algorithms were selected, such as Decision Stump, M5 model tree, M5 regression tree, RepTree, M5 rules, and linear regression in order to study the data. Our experimental results illustrate the complexity associated to the performance of road transport systems mainly because of the dependency between the choices of influencing factors and geographic location of the road segment.

1 - 29 of 29
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