17,290 research outputs found

    Optimizing Urban Distribution Routes for Perishable Foods Considering Carbon Emission Reduction

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    The increasing demand for urban distribution increases the number of transportation vehicles which intensifies the congestion of urban traffic and leads to a lot of carbon emissions. This paper focuses on carbon emission reduction in urban distribution, taking perishable foods as the object. It carries out optimization analysis of urban distribution routes to explore the impact of low carbon policy on urban distribution routes planning. On the base of analysis of the cost components and corresponding constraints of urban distribution, two optimization models of urban distribution route with and without carbon emissions cost are constructed, and fuel quantity related to cost and carbon emissions in the model is calculated based on traffic speed, vehicle fuel quantity and passable time period of distribution. Then an improved algorithm which combines genetic algorithm and tabu search algorithm is designed to solve models. Moreover, an analysis of the influence of carbon tax price is also carried out. It is concluded that in the process of urban distribution based on the actual network information, the path optimization considering the low carbon factor can effectively reduce the distribution process of CO2, and reduce the total cost of the enterprise and society, thus achieving greater social benefits at a lower cost. In addition, the government can encourage low-carbon distribution by rationally adjusting the price of carbon tax to achieve a higher social benefit

    The research on optimization of liner route between China to Middle East

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    Train-scheduling optimization model for railway networks with multiplatform stations

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    This paper focuses on optimizing the schedule of trains on railway networks composed of busy complex stations. A mathematical formulation of this problem is provided as a Mixed Integer Linear Program (MILP). However, the creation of an optimal new timetable is an NP-hard problem; therefore, the MILP can be solved for easy cases, computation time being impractical for more complex examples. In these cases, a heuristic approach is provided that makes use of genetic algorithms to find a good solution jointly with heuristic techniques to generate an initial population. The algorithm was applied to a number of problem instances producing feasible, though not optimal, solutions in several seconds on a laptop, and compared to other proposals. Some improvements are suggested to obtain better results and further improve computation time. Rail transport is recognized as a sustainable and energy-efficient means of transport. Moreover, each freight train can take a large number of trucks off the roads, making them safer. Studies in this field can help to make railways more attractive to travelers by reducing operative cost, and increasing the number of services and their punctuality. To improve the transit system and service, it is necessary to build optimal train scheduling. There is an interest from the industry in automating the scheduling process. Fast computerized train scheduling, moreover, can be used to explore the effects of alternative draft timetables, operating policies, station layouts, and random delays or failures.Postprint (published version

    Effects of speed reduction in climb, cruise and descent phases to generate linear holding at no extra fuel cost

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    Best paper Award in Trajectory Optimisation Track - ICRAT 2016Speed reduction strategies have proved to be useful to recover delay if air traffic flow management regulations are cancelled before initially planned. Considering that for short- haul flights the climb and descent phases usually account for a considerable percentage of the total trip distance, this paper extends previous works on speed reduction in cruise to the whole flight. A trajectory optimization software is used to compute the maximum airborne delay (or linear holding) that can be performed without extra fuel consumption if compared with the nominal flight. Three cases are studied: speed reduction only in cruise; speed reduction in the whole flight, but keeping the nominal cruise altitude; and speed reduction for the whole flight while also optimizing the cruise altitude to maximize delay. Three representative flights have been simulated, showing that the airborne delay increases significantly in the two last cases with nearly 3-fold time for short-haul flights and 2-fold for mid- hauls with the first case. Results also show that fuel and time are traded along different phases of flight in such a way the airborne delay is maximized while the total fuel burn is kept constant.Peer ReviewedAward-winningPostprint (published version

    Recent advances in industrial wireless sensor networks towards efficient management in IoT

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    With the accelerated development of Internet-of- Things (IoT), wireless sensor networks (WSN) are gaining importance in the continued advancement of information and communication technologies, and have been connected and integrated with Internet in vast industrial applications. However, given the fact that most wireless sensor devices are resource constrained and operate on batteries, the communication overhead and power consumption are therefore important issues for wireless sensor networks design. In order to efficiently manage these wireless sensor devices in a unified manner, the industrial authorities should be able to provide a network infrastructure supporting various WSN applications and services that facilitate the management of sensor-equipped real-world entities. This paper presents an overview of industrial ecosystem, technical architecture, industrial device management standards and our latest research activity in developing a WSN management system. The key approach to enable efficient and reliable management of WSN within such an infrastructure is a cross layer design of lightweight and cloud-based RESTful web service
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