12,164 research outputs found

    A multi-agent platform for auction-based allocation of loads in transportation logistics

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    This paper describes an agent-based platform for the allocation of loads in distributed transportation logistics, developed as a collaboration between CWI, Dutch National Center for Mathematics and Computer Science, Amsterdam and Vos Logistics Organizing, Nijmegen, The Netherlands. The platform follows a real business scenario proposed by Vos, and it involves a set of agents bidding for transportation loads to be distributed from a central depot in the Netherlands to different locations across Germany. The platform supports both human agents (i.e. transportation planners), who can bid through specialized planning and bidding interfaces, as well as automated, software agents. We exemplify how the proposed platform can be used to test both the bidding behaviour of human logistics planners, as well as the performance of automated auction bidding strategies, developed for such settings. The paper first introduces the business problem setting and then describes the architecture and main characteristics of our auction platform. We conclude with a preliminary discussion of our experience from a human bidding experiment, involving Vos planners competing for orders both against each other and against some (simple) automated strategies

    Problems and prospects of non-motorized public transport integration in developing cities

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    The benefits and costs of the paid category of non-motorized public transport (NMPT) –especially three wheeler cycle rickshaws – have long been a major transport planning problem in many developing cities. Policy measures to restrict or eliminate non-motorized vehicles, especially NMPTs, from urban arterials and other feeder networks have already been implemented in developing cities as diverse as Delhi, Bangkok, Jakarta, Manila, Surabaya, Beijing and Bogotá. Over the last few years, the government of Bangladesh has implemented policies to phase out non-motorized transport, particularly rickshaws, from the major traffic spines of Dhaka City. The acceptability, rationality and implication of such ‘solutions’ are widely argued in Bangladesh, as well as internationally. The argument is severe in Dhaka, the case study of this research, considering social acceptability, economic response, fuel free eco-friendly characteristics and magnitude of role of rickshaw in sustaining the traffic and mobility needs of citizens. Therefore, rather than simply pursuing policies to eliminate NMPT, a better approach may be to integrate motorized and non-motorized vehicles as complementary rather than competitive forces in meeting the comprehensive demand of Dhaka’s transport. With the backdrop and given the international significance of the problem, this paper will delineate a preliminary framework for the future place of the NMPT-rickshaw and explore the problems as well as opportunities for its sustainable co-existence in a mixed mode transport stream that best meets the network performance needs of Dhaka

    Robust Structured Low-Rank Approximation on the Grassmannian

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    Over the past years Robust PCA has been established as a standard tool for reliable low-rank approximation of matrices in the presence of outliers. Recently, the Robust PCA approach via nuclear norm minimization has been extended to matrices with linear structures which appear in applications such as system identification and data series analysis. At the same time it has been shown how to control the rank of a structured approximation via matrix factorization approaches. The drawbacks of these methods either lie in the lack of robustness against outliers or in their static nature of repeated batch-processing. We present a Robust Structured Low-Rank Approximation method on the Grassmannian that on the one hand allows for fast re-initialization in an online setting due to subspace identification with manifolds, and that is robust against outliers due to a smooth approximation of the ℓp\ell_p-norm cost function on the other hand. The method is evaluated in online time series forecasting tasks on simulated and real-world data

    Enablers and Impediments for Collaborative Research in Software Testing: An Empirical Exploration

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    When it comes to industrial organizations, current collaboration efforts in software engineering research are very often kept in-house, depriving these organizations off the skills necessary to build independent collaborative research. The current trend, towards empirical software engineering research, requires certain standards to be established which would guide these collaborative efforts in creating a strong partnership that promotes independent, evidence-based, software engineering research. This paper examines key enabling factors for an efficient and effective industry-academia collaboration in the software testing domain. A major finding of the research was that while technology is a strong enabler to better collaboration, it must be complemented with industrial openness to disclose research results and the use of a dedicated tooling platform. We use as an example an automated test generation approach that has been developed in the last two years collaboratively with Bombardier Transportation AB in Sweden

    Thirty Years of Machine Learning: The Road to Pareto-Optimal Wireless Networks

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    Future wireless networks have a substantial potential in terms of supporting a broad range of complex compelling applications both in military and civilian fields, where the users are able to enjoy high-rate, low-latency, low-cost and reliable information services. Achieving this ambitious goal requires new radio techniques for adaptive learning and intelligent decision making because of the complex heterogeneous nature of the network structures and wireless services. Machine learning (ML) algorithms have great success in supporting big data analytics, efficient parameter estimation and interactive decision making. Hence, in this article, we review the thirty-year history of ML by elaborating on supervised learning, unsupervised learning, reinforcement learning and deep learning. Furthermore, we investigate their employment in the compelling applications of wireless networks, including heterogeneous networks (HetNets), cognitive radios (CR), Internet of things (IoT), machine to machine networks (M2M), and so on. This article aims for assisting the readers in clarifying the motivation and methodology of the various ML algorithms, so as to invoke them for hitherto unexplored services as well as scenarios of future wireless networks.Comment: 46 pages, 22 fig

    Electricity powering combustion: hydrogen engines

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    Hydrogen is ameans to chemically store energy. It can be used to buffer energy in a society increasingly relying on renewable but intermittent energy or as an energy vector for sustainable transportation. It is also attractive for its potential to power vehicles with (near-) zero tailpipe emissions. The use of hydrogen as an energy carrier for transport applications is mostly associated with fuel cells. However, hydrogen can also be used in an internal combustion engine (ICE). When converted to or designed for hydrogen operation, an ICE can attain high power output, high efficiency and ultra low emissions. Also, because of the possibility of bi-fuel operation, the hydrogen engine can act as an accelerator for building up a hydrogen infrastructure. The properties of hydrogen are quite different from the presently used hydrocarbon fuels, which is reflected in the design and operation of a hydrogen fueled ICE (H2ICE). These characteristics also result in more flexibility in engine control strategies and thus more routes for engine optimization. This article describes the most characteristic features of H2ICEs, the current state of H2ICE research and demonstration, and the future prospects

    Mass-Market Receiver for Static Positioning: Tests and Statistical Analyses

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    Nowadays, there are several low cost GPS receivers able to provide both pseudorange and carrier phase measurements in the L1band, that allow to have good realtime performances in outdoor condition. The present paper describes a set of dedicated tests in order to evaluate the positioning accuracy in static conditions. The quality of the pseudorange and the carrier phase measurements let hope for interesting results. The use of such kind of receiver could be extended to a large number of professional applications, like engineering fields: survey, georeferencing, monitoring, cadastral mapping and cadastral road. In this work, the receivers performance is verified considering a single frequency solution trying to fix the phase ambiguity, when possible. Different solutions are defined: code, float and fix solutions. In order to solve the phase ambiguities different methods are considered. Each test performed is statistically analyzed, highlighting the effects of different factors on precision and accurac

    Efficiency optimization of the transportation supply chain activity: the maritime option for Volkswagen Autoeuropa

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    Field Lab of Entrepreneurial Innovative VenturesWith the current pressures for companies to reduce their CO2 emissions levels and the worldwide competition more fierce than ever it becomes critical for companies to optimize their processes and improve supply chain efficiency. Develop solutions that could satisfy both these requirements is mandatory to improve and sustain today’s businesses. For Portuguese industries with high transportation costs the maritime option has become increasingly reliable, experiencing a huge structural and technological improvement in the past decades. This work project aims the study of maritime transportation feasibility for Volkswagen Autoeuropa company; it combines the strong theoretical background with a data analysis and multi-scenario assessment. The methodologies used were the billing analysis, at the beginning, then followed by a thorough analysis of transportation and inventory costs and volumes which led to a range of potential supplies to be transported by maritime. At the end the result was 3 possible routes which demonstrate after the analysis only one be a viable option. It was performed also a CO2 analysis, a risk analysis and consequent contingency plan in order to finalize a complete approach to this maritime projectNSBE - UN
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