3 research outputs found

    Wireless communication, identification and sensing technologies enabling integrated logistics: a study in the harbor environment

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    In the last decade, integrated logistics has become an important challenge in the development of wireless communication, identification and sensing technology, due to the growing complexity of logistics processes and the increasing demand for adapting systems to new requirements. The advancement of wireless technology provides a wide range of options for the maritime container terminals. Electronic devices employed in container terminals reduce the manual effort, facilitating timely information flow and enhancing control and quality of service and decision made. In this paper, we examine the technology that can be used to support integration in harbor's logistics. In the literature, most systems have been developed to address specific needs of particular harbors, but a systematic study is missing. The purpose is to provide an overview to the reader about which technology of integrated logistics can be implemented and what remains to be addressed in the future

    Multi-Services MAC Protocol for Wireless Networks

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    Multi-services MAC protocol for wireless Networks

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    Summary form only given. Due to random access in wireless networks using CSMA/CA like in Wifi networks, the integration of services with a lot of quality of service needs is impossible. In this paper, we propose to study and to evaluate a new MAC protocol that takes into account different types of traffic (e.g.. voice and data) and for each traffic, different priority levels are considered. To improve the QoS of WIFI MAC protocols, we add a selective reject and push-out mechanisms. To model our protocol, using Markov chain is impossible because it provides Markov chain with a large state-space. This is due to the resource management and user mobility. Thus, we propose to build an aggregated Markov chain with a less state-space that allows to compute easily performance measures. We have used stochastic comparisons of Markov chains to prove that the considered access protocol (with selective reject and push-out mechanisms) gives less loss rates of high priority connections (data and voices) than the traditional one (without selective reject and push-out mechanisms). We give numerical results to confirm mathematical proofs.ou
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