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Lower and upper bound algorithms for the real-time train scheduling and routing problem in a railway network

IFAC-PapersOnLine 2016年第3期49卷 215-220页

作者： Samà, M. D'Ariano, A. Pacciarelli, D. Corman, F. Roma Tre University Department of Engineering via della Vasca Navale Rome79-00146 Italy Delft University of Technology Department of Maritime and Transport Technology Mekelweg 2 – 2628 CD Delft Netherlands

This paper focuses on the development of new algorithms for the real-time train scheduling and routing problem in a complex and busy railway network. Since this is a strongly NP-hard problem and practical size instances are complex, simple heuristics are typically adopted in practice to compute feasible but low quality schedules in a short computation time. In order to compute good quality solutions, we consider a mixed-integer linear programming formulation of the problem and solve it with a commercial solver. However, the resolution of this formulation by a commercial solver often takes a too long computation time. Therefore, a new methodology based on the relaxation of some train routing constraints in the formulation is proposed for the quick computation of a good quality lower bound. The lower bound solution is then transformed via a constructive metaheuristic into a feasible schedule, representing a good quality upper bound to the problem. Computational experiments are performed on several disturbed traffic situations for two practical case studies from the Dutch and British railways. The results show that the new lower and upper bounds are computed in a few seconds and are often of similar quality to the ones computed by the commercial solver in hours of computation. © 2016

关键词： Problem solving Complex networks Computational complexity Integer programming Railroad transportation Railroads routing algorithms Scheduling Commercial solvers Computational experiment Disjunctive programming Lower and upper bounds Meta heuristics Mixed integer linear programming Railway traffic management Traffic situations

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Multiple Parameters Optimization for Cognitive Radio Environment Employing Cuckoo Search Algorithm

Multiple Parameters Optimization for Cognitive Radio Environ...

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2018 Al Mansour International Conference on New Trends in Computing, Communication, and Information Technology, NTCCIT 2018

作者： Al-Azzawi, May Kamil Hatem, Haider S. Shujaa, Mohammad Ibrahim Al-Mansour University College Baghdad Iraq Madenat Alelem University College Baghdad Iraq Electrical Engineering Technical College Baghdad Iraq

ISBN: (纸本)9781538684528

A spectrum opportunity considers the most significant feature, wherever channel obtain ability has to be exceedingly taking into account in several routing train in cognitive radio network. A choice of a whole path, starting from source to specific destination, is likely to be completed one time if we have stationary topology in case of a primary user is inattentive for the whole message time. To effectively transmit data packets and to develop cognitive routing protocols and to enforce challenges as a result of the changing nature of the obtainable spectrum, this research proposes an optimization path routing algorithm depend on the basis of the one of inspired approaches (Cuckoo Search Algorithm) to speed up the exploration for the optimal routes. This algorithm is a new meta-heuristic algorithm. It is being used for solving optimization problem. This study presents an advanced routing algorithm specified for this networks, this algorithm is based on the cuckoo search algorithm, makes the transmission process effectual, adaptive in addition to scalable with a cumulative number of nodes. The new guideline proposed better satisfies the demands of Quality of Services (QoS) and show that the algorithm is valid and effective in controlling the packet loss ratio, time delay and the residual bandwidth while satisfying service requirements, emphasizing of some important characteristics of cuckoo search algorithm. © 2018 IEEE.

关键词： routing algorithms

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Traffic aware relay based routing and deployment algorithms in wireless sensor networks

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Information Technology Journal 2013年第13期12卷 2512-2518页

作者： Zeng, Bin Yao, Lu Wang, Rui Department of Management Engineering Research Center of Information Managemen Naval University of Engineering No. 717 JieFang Road Wuhan Hubei 430033 China

For energy efficient routing scheme in the wireless sensor networks, it is important to use sub-optimal paths supported by relay nodes to increase the survivability and lifetime of networks. However, through routing algorithms play an important role, they will not be able to make good performance without an appropriate deployment of relays. First, the co-design problem, relay routing problem and relay deployment problem are formulated together with the end to end network energy consumption. Second, an optimal routing Tree algorithm considering network traffic, are proposed in order to significantly reduce the network energy consumption through the efficient utilization of the deployed relay nodes. Third, the relay deployment problem is considered to find the optimal locations for a given number. A traffic-aware relay deployment algorithm is proposed by adopting the network routing and traffic infonnation. Our algorithms has been evaluated through a series of simulations and compared with state-of-the-art approaches. The results show that they lead to significant improvement on the network energy consumption over the existing traffic-unaware strategies. © 2013 Asian Network for Scientific Information.

关键词： routing algorithms

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A new routing algorithm based on opportunistic networks

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International Journal of Information and Communication Technology 2017年第1期11卷 81-93页

作者： Dong, Shi Qi, Yingchun Zhou, Dingding School of Computer Science and Technology Zhoukou Normal University Henan Zhoukou China School of Computer Science and Engineering Huazhong University of Science and Technology Wubei Wuhan China Department of Laboratory and Equipment Management Zhoukou Normal University Henan Zhoukou China

Opportunistic network completes the communication between nodes by 'storage-carry-forward' mode, the traditional routing algorithms can not be applied to the opportunistic network, so this article proposes network routing algorithm MPRA based on an efficient opportunistic network. The algorithm is based on the mobility prediction method to solve routing problems. We use existing mobility prediction method and apply it into the routing algorithm. Compared to existing routing method of opportunity network, MPRA method can handle dynamic route problem, improve the transmission success rate and decrease the transmission delay. Moreover, the algorithm can reduce the routing overhead and short the cache time. © Copyright 2017 Inderscience Enterprises Ltd.

关键词： routing algorithms

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A Message Matching routing Algorithm Based on Node Sociality in Opportunistic Networks

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Procedia Computer Science 2018年 129卷 175-177页

作者： Nan Zhao Feng Zeng Wenjia Li School of Software Central South University Changsha China Department of Computer Science New York Institute of Technology New York USA

Inspired by the importance of grouping in the communication networks such as Facebook, Twitter, Wechat, we choose appropriate forwarding channels for different types of messages in order to improve the rate of message success forwarding, while reducing network overhead and addressing the problem of network congestion. In this paper, we put forward the concept of circle of friends and an effective classification method to assign the circle of friends that the node belongs according to social attributes of node. A message matching routing algorithm (MMAR) is designed to help messages forward, in which nodes select the corresponding circle of friends based on the type of message. The simulation results show that the proposed routing algorithm based on sociality is superior to other classical routing algorithms in forwarding rate, delay and routing overhead.

关键词： social attributes circle of friends routing algorithms

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Fuzzy power-optimised clustering routing algorithm for wireless sensor networks

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IET WIRELESS SENSOR SYSTEMS 2017年第5期7卷 130-137页

作者： Li, Jianpo Hou, Xindi Su, Dan Munyemana, Jean De Dieu Northeast Elect Power Univ Sch Informat Engn Jilin 132012 Jilin Peoples R China

Transmission power control is an effective method to reduce energy consumption for wireless sensor networks. However, the current algorithms of power control have relatively low accuracy. At the same time, the parameters cannot be adjusted dynamically. In order to improve the energy utilisation as well as data transmission efficiency and balance the load, therefore, a fuzzy power-optimised clustering routing algorithm is proposed in this study. The algorithm optimises the iteration radius and classifies the sensor nodes into different categories according to their node degree. Then select the cluster head by multi-parameter iteration adaptively among the same category, and optimise the cluster structure with a comprehensive consideration of parameters such as degree of centralisation, distance between node and base station and so on. Finally, fuzzy control is used to adjust the transmission power of cluster nodes dynamically to minimise the energy consumption. Simulation results show that when the average cluster radius R-L = 60, weight of election parameters alpha = 0.2, adjustment parameter of cluster radius eta = 0.7, compared with other similar algorithms, the proposed algorithm prolongs the lifetime by at least 42.2% and increases the amount of data packets by at least 40.1%.

关键词： Fuzzy algorithms power transmission control power transmission iterative methods cluster head Cluster structure routing algorithms energy utilisation Power control data packets

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A learning-based thermal-sensitive power optimization approach for optical NoCs

A learning-based thermal-sensitive power optimization approa...

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作者： Zhang, Zhe Ye, Yaoyao Department of Micro/Nano Electronics School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University Shanghai200240 China

Optical networks-on-chip (NoCs) based on silicon photonics have been proposed as emerging on-chip communication architectures for chip multiprocessors with large core counts. However, due to the thermal sensitivity of optical devices used in optical NoCs, on-chip temperature variations cause significant thermal induced optical power loss, which would counteract the power advantages of optical NoCs. To tackle this problem, in this work, we propose a learning-based thermal-sensitive power optimization approach for mesh or torus-based optical NoCs in the presence of temperature variations. The key techniques proposed include an initial device-setting and thermal-tuning mechanism that is a device-level optimization technique, and a learning-based thermal-sensitive adaptive routing algorithm that is a network-level optimization technique. Simulation results of an 8x8 mesh-based optical NoC show that the proposed initial device-setting and thermal-tuning mechanism confines the worst-case thermal-induced optical energy consumption to be on the order of tens of pJ/bit, by avoiding significant thermal-induced optical power loss caused by temperature dependent wavelength shifts. Besides, it shows that the learning-based thermal-sensitive adaptive routing algorithm is able to find an optimal path with the minimum estimated thermal-induced optical power consumption for each communication pair. The proposed routing has a greater space for optimization, especially for applications with more long-distance traffic. © 2018 ACM.

关键词： routing algorithms

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A Column Generation Algorithm for Vehicle Scheduling and routing Problems

arXiv

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arXiv 2018年

作者： Faiz, Tasnim Ibn Vogiatzis, Chrysafis Noor-E-Alam, Md. Department of Mechanical and Industrial Engineering Northeastern University 360 Huntington Ave BostonMA02115 United States Department of Industrial and Systems Engineering North Carolina A and T State University 1601 E. Market St GreensboroNC27411 United States

During natural or anthropogenic disasters, humanitarian organizations face a series of time-sensitive tasks. One of the tasks involves picking up critical resources (e.g., first aid kits, blankets, water) from warehouses and delivering them to the affected people. To successfully deliver these items to the people in need, the organization needs to make decisions that range from the quick acquisition of vehicles from the local market, to the preparation of pickup and delivery schedules and vehicle routes. During crises, the supply of vehicles is often limited, their acquisition cost is steep, and special rental periods are imposed. At the same time, the affected area needs the aid materials as fast as possible, and deliveries must be made within due time. Therefore, it is imperative that the decisions of acquiring, scheduling, and routing of vehicles are made optimally and quickly. In this paper, we consider a variant of a truckload open vehicle routing problem with time windows, which is suitable for modeling vehicle routing operations during a humanitarian crisis. We present two integer linear programming models to formulate the problem. The first one is an arc-based mixed integer linear programming model that is solved using a general purpose solver. The second one, on the other hand, is based on a path-based formulation, for which we design a column generation framework so as to solve it. Finally, we perform numerical experiments and compare the performance of the two models. The comparison shows that the latter path-based formulation outperforms the former without sacrificing solution quality when employing our column generation framework. Copyright © 2018, The Authors. All rights reserved.

关键词： routing algorithms

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routing metrics depending on previous edges: The mn taxonomy and its corresponding solutions

arXiv

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arXiv 2018年

作者： Bemten, Amaury Van Guck, Jochen W. MacHuca, Carmen Mas Kellerer, Wolfgang Lehrstuhl für Kommunikationsnetze Technical University of Munich Germany

The routing algorithms used by current operators aim at coping with the demanded QoS requirements while optimizing the use of their network resources. These algorithms rely on the optimal substructure property (OSP), which states that an optimal path contains other optimal paths within it. However, we show that QoS metrics such as queuing delay and buffer consumption do not satisfy this property, which implies that the used algorithms lose their optimality and/or completeness. This negatively impacts the operator economy by causing a waste of network resources and/or violating Service Level Agreements (SLAs). In this paper, we propose a new so-called Mn taxonomy defining new metric classes. An Mn metric corresponds to a metric which requires the knowledge of the n previously traversed edges to compute its value at a given edge. Based on this taxonomy, we present three solutions for solving routing problems with the newly defined classes of metrics. We show that state-ofthe- A rt algorithms based on the OSP indeed lose their original optimality and/or completeness properties while our proposed solutions do not, at the price of an increased computation time. Copyright © 2018, The Authors. All rights reserved.

关键词： routing algorithms

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Research on Efficient routing Algorithm Based on Dynamic Segmentation Network Coding

Research on Efficient Routing Algorithm Based on Dynamic Seg...

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作者： Li Cong Wu Yonghao City College Wuhan University of Science Technology Wuhan University

In order to solve the problem of existing routing algorithms,an efficient routing algorithm based on dynamic segmentation network coding(ERBNC) is *** compressing the header of the encoded packet,deleting the redundant ACK packet and setting the priority of sending the encoded packet,the proposed algorithm reduces the network overhead and packet average end-to-end *** simulation experiments of ERBNC algorithm,dynamic segmented network coding(DSNC) algorithm and segmented network coding(SNC) algorithm were completed by using OPNET simulation *** performance of various algorithms is compared and *** simulation results show that the ERBNC algorithm can effectively reduce the network overhead and reduce the average end-to-end delay of data packets.

关键词： Delay Tolerant Networks routing algorithms Network Coding Decoding Predictions Redundant Control

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