142 research outputs found

    A study on RFID adoption for vehicle tracking in container terminal

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    Purpose: Numerous studies discuss that Radio Frequency Identification (RFID) technology can provide better container handling efficiency; however, relative lack of research concerns the tracking and monitoring the movement of vehicle in the container terminal environment. Thus, this study aims at discussing the feasibility of applying RFID for vehicle tracking purpose in a container terminal. Design/methodology/approach: This study makes use of a series of experiments in a container terminal to discuss the factors that affect the use of RFID in the terminal. The possibility and accuracy of using RFID in such challenging environment is also investigated. These propositions are investigated by a case study. Findings: The experimental results indicate that the RFID communication is good at the containers area which occupies nearly all the area in the container terminal. However, in other area such as sea side and free area, the performance is not good and 100% readability only achieved in 5m and 10m in free area and sea side respectively. Originality/value: The container terminal environment, which consists of different transport vehicles for onward transportation, will affect the performance of RFID readability. Poor setup of the RFID reader and tag will lower the feasibility of RFID adoption as well as increase the cost. In order to address the challenges of implementing RFID in the container terminal environment, this paper provides a series of real site testing experiments to study the RFID performance in the container terminal environment. This represents an original contribution of value to future research and practice in the RFID adoptions in container terminal environmentPeer Reviewe

    An efficient ant colony system based on receding horizon control for the aircraft arrival sequencing and scheduling problem

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    The aircraft arrival sequencing and scheduling (ASS) problem is a salient problem in air traffic control (ATC), which proves to be nondeterministic polynomial (NP) hard. This paper formulates the ASS problem in the form of a permutation problem and proposes a new solution framework that makes the first attempt at using an ant colony system (ACS) algorithm based on the receding horizon control (RHC) to solve it. The resultant RHC-improved ACS algorithm for the ASS problem (termed the RHC-ACS-ASS algorithm) is robust, effective, and efficient, not only due to that the ACS algorithm has a strong global search ability and has been proven to be suitable for these kinds of NP-hard problems but also due to that the RHC technique can divide the problem with receding time windows to reduce the computational burden and enhance the solution's quality. The RHC-ACS-ASS algorithm is extensively tested on the cases from the literatures and the cases randomly generated. Comprehensive investigations are also made for the evaluation of the influences of ACS and RHC parameters on the performance of the algorithm. Moreover, the proposed algorithm is further enhanced by using a two-opt exchange heuristic local search. Experimental results verify that the proposed RHC-ACS-ASS algorithm generally outperforms ordinary ACS without using the RHC technique and genetic algorithms (GAs) in solving the ASS problems and offers high robustness, effectiveness, and efficienc

    An ant colony optimization approach for maximizing the lifetime of heterogeneous wireless sensor networks

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    Maximizing the lifetime of wireless sensor networks (WSNs) is a challenging problem. Although some methods exist to address the problem in homogeneous WSNs, research on this problem in heterogeneous WSNs have progressed at a slow pace. Inspired by the promising performance of ant colony optimization (ACO) to solve combinatorial problems, this paper proposes an ACO-based approach that can maximize the lifetime of heterogeneous WSNs. The methodology is based on finding the maximum number of disjoint connected covers that satisfy both sensing coverage and network connectivity. A construction graph is designed with each vertex denoting the assignment of a device in a subset. Based on pheromone and heuristic information, the ants seek an optimal path on the construction graph to maximize the number of connected covers. The pheromone serves as a metaphor for the search experiences in building connected covers. The heuristic information is used to reflect the desirability of device assignments. A local search procedure is designed to further improve the search efficiency. The proposed approach has been applied to a variety of heterogeneous WSNs. The results show that the approach is effective and efficient in finding high-quality solutions for maximizing the lifetime of heterogeneous WSNs

    Risk Sorting for Enterprise under EC Environments

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    With the rapid development of internet and emerging of global economic, risk management for enterprise under EC (Electronic Commerce) environments has drawn attentions of many researchers. In this paper, the characteristics of risk for EC enterprise are analyzed. Further, focused on the project organization mode and the uncertain factor of the enterprise under EC, which are main different characteristics from the conventional enterprise, enterprise risk sorting, which is one of the key problems of risk management under EC environments, is studied by using fuzzy ISODATA cluster method based on fuzzy describing of risks. Case study suggests the effectiveness of the method

    An Aircraft Service Staff Rostering using a Hybrid GRASP Algorithm

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    The aircraft ground service company is responsible for carrying out the regular tasks to aircraft maintenace between their arrival at and departure from the airport. This paper presents the application of a hybrid approach based upon greedy randomized adaptive search procedure (GRASP) for rostering technical staff such that they are assigned predefined shift patterns. The rostering of staff is posed as an optimization problem with an aim of minimizing the violations of hard and soft constraints. The proposed algorithm iteratively constructs a set of solutions by GRASP. Furthermore, with multi-agent techniques, we efficiently identify an optimal roster with minimal constraint violations and fair to employees. Experimental results are included to demonstrate the effectiveness of the proposed algorithm

    CBR Based Risk Management for Virtual Organization

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    After researching various factors that influence the management and decisions on risk management of virtual organization, CBR based risk management for virtual organization is proposed in this paper. Relevant theories of fuzzy mathematics are utilized in the process of modifying the corresponding similar cases. Correct application of the new method is demonstrated substantially through instance simulation

    A memetic particle swarm optimisation algorithm for dynamic multi-modal optimisation problems

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    Copyright @ 2011 Taylor & Francis.Many real-world optimisation problems are both dynamic and multi-modal, which require an optimisation algorithm not only to find as many optima under a specific environment as possible, but also to track their moving trajectory over dynamic environments. To address this requirement, this article investigates a memetic computing approach based on particle swarm optimisation for dynamic multi-modal optimisation problems (DMMOPs). Within the framework of the proposed algorithm, a new speciation method is employed to locate and track multiple peaks and an adaptive local search method is also hybridised to accelerate the exploitation of species generated by the speciation method. In addition, a memory-based re-initialisation scheme is introduced into the proposed algorithm in order to further enhance its performance in dynamic multi-modal environments. Based on the moving peaks benchmark problems, experiments are carried out to investigate the performance of the proposed algorithm in comparison with several state-of-the-art algorithms taken from the literature. The experimental results show the efficiency of the proposed algorithm for DMMOPs.This work was supported by the Key Program of National Natural Science Foundation (NNSF) of China under Grant no. 70931001, the Funds for Creative Research Groups of China under Grant no. 71021061, the National Natural Science Foundation (NNSF) of China under Grant 71001018, Grant no. 61004121 and Grant no. 70801012 and the Fundamental Research Funds for the Central Universities Grant no. N090404020, the Engineering and Physical Sciences Research Council (EPSRC) of UK under Grant no. EP/E060722/01 and Grant EP/E060722/02, and the Hong Kong Polytechnic University under Grant G-YH60

    Virtual Enterprises Risk Management DSS under Electronic Commerce

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    Risk management is important to the development of enterprise as well as social-economic prosperity. Virtual enterprise is the potential mode of future enterprise under electronic commerce environment and the risk management for it is a popular research area recently. Due to the complexity of its risk management a decision support system (DSS) with 3-bases-1-cell structure was designed. By coordinating data base, model base, algorithm base and dialogue cell, the functions of project management, risk identification, risk assessment, risk evaluation and risk programming was supported. The user-friendly system has such main characteristics as generality for verity virtual enterprise as well as different projects and the flexibility of model and algorithm, ensuring a standardized, scientific and informational risk management for virtual enterprises

    Risk Evaluation for Virtual Enterprise

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    Virtual Enterprise is the potential mode of enterprise in the future. The risk management for virtual enterprise is the new research area recently. In virtual enterprise, the enterprise operation is always organized by project mode and there is always less historical data and there are many uncertain factors. Hence, in this paper, the fuzzy synthetic evaluation model for the risk evaluation of virtual enterprise is established focus on the project mode and uncertain characteristics of virtual enterprise. In the 5 levels model, the goal and sub-goal of the enterprise, the process of the project, as well as the risk event and risk factors are considered. The case study suggests that the method is useful

    A Risk Identification Method of Virtual Enterprise

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    Virtual enterprise is the potential mode of future enterprise under global economic environment and the risk management for it is a popular research area recently. Risk identification is the key phrase of risk management. Considering the risk identification problem in the virtual enterprise, a new identification method based on the BP network is provided in this paper. Using this method and the data related to the problem, the possible to take place of the risks could be obtained by training the neural network, so that risks can be investigated in time and managed effectively. The simulation results prove its validit
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