铁路客运中转径路计算模型研究

针对目前径路计算中缺乏实时性、径路维护工作量大、径路选择缺乏灵活性等问题,从分析径路计算方式人手,结合车站发售通票业务特点,提出一种改进的统一径路计算模型。该模型充分平衡预先计算与实时计算的优点,在保证径路有效性和合理性的前提下,对径路计算中的车站个性径路信息和全路共性信息进行有效剥离,从根本上解决了径路计算存在的问题。

基于车次径路约束下的客运径路生成算法优化

针对目前客票径路计算中径路信息与实际旅客出行径路之间存在的差异性,从分析径路生成的计算模型出发,结合铁路通票业务背景,提出一种车次约束机制下的径路生成计算方法。算法以选择性集中存储为径路存取方式,实现径路公共信息的全路共享与车站特殊径路的分布式存取,有效压缩径路信息存储空间,提高径路选择效率;以车站-车次邻接表为基本数据结构,将铁路路网图改进为列车约束下的列车可达图,保证车站生成个性化径路的合理性和有效性;算法摒弃原有径路计算只计算本站至全路各个结算站间最短K路径的方法,分车站特殊径路计算和公共径路计算两步实现径路的计算,从根本上保证径路计算的有效性,解决通票径路与列车走行径路不符问题,实现了对现有径路生成算法的优化。

铁路车流经由计算系统分析

车流径路关系到制票、收入检查、精密统计、清算及成本核算等铁路运输生产的诸多方面。本系统提出了计算径路的概念 ,首创了特定经由标记语言 ,用以解决传统车流径路系统的难点问题 ,并提供一套直观易用。

计算机监测统计迂回车流的实现

阐述了迂回车流统计监测采用人工筛选登记不准，影响铁路的收入清算工作，采用计算机径路计算监测统计迂回车流。

Dissociation Pathway Analysis of Thymine under Low Energy VUV Photon Excitation

Photon-induced dissociation pathways of thymine are investigated with vacuum ultraviolet photoionization mass spectrometry and theoretical calculations. The photoionization mass spectra of thymine at different photon energy are measured and presented. By selecting suitable photon energy, exclusively molecular ion m/z=126 is obtained. At photon energy of 12.0 eV, the major ionic fragments at m/z=98, 97, 84, 83, 70, and 55 are obtained, which are assigned to C4H6N2O＋, C4H5N2O＋, C3H4N2O＋ （or C4H6NO＋）, C4H5NO＋, C2NO2＋, and C3H5N＋, respectively. With help of theoretical calculations, the detailed dissociation pathways of thymine at low energy are well established.

HiQoS:An SDN-Based Multipath QoS Solution

Today's Internet architecture provides only "best effort" services,thus it cannot guarantee quality of service(QoS) for applications.Software Defined Network(SDN)is a new approach to computer networking that separates control plane and forwarding planes,and has the advantage of centralized control and programmability.In this paper,we propose HiQoS that provides QoS guarantees using SDN.Moreover,HiQoS makes use of multiple paths between source and destination and queuing mechanisms to guarantee QoS for different types of traffic.Experimental results show that our HiQoS scheme can reduce delay and increase throughput to guarantee QoS.Very importantly,HiQoS recovers from link failure very quickly by rerouting traffic from failed path to other available path.

Horizontal-Based Orchestration for Multi-Domain SFC in SDN/NFV-Enabled Satellite/Terrestrial Networks

It's promising to use Software-Defined Networking(SDN) and Network Functions Virtualization(NFV) to integrate satellite and terrestrial networks. To construct network service function chains in such a multi-domain environment, we propose a horizontal-based Multi-domain Service Function Chaining(Md-SFC) orchestration framework. In this framework, multi-domain orchestrators can coordinate with each other to guarantee the end-to-end service quality. Intra-domain orchestrators also coordinate SDN controllers and NFV management components to implement intra-domain service function chains. Based on this, we further propose a heuristic SFC mapping algorithm with a cooperative inter-domain path calculation method to map service function chains to infrastructures. In this method, master multi-domain orchestrator and intra-domain orchestrators coordinate to select proper inter-domain links. We compare the cooperative method with a naive uncooperative way that domains' topology information is provided to the master multi-domain orchestrator and it calculates the shortest inter-domain path between intra-domain service function chains directly. Simulation results demonstrate that our solution is feasible. It is able to construct end-to-end performance guaranteed service function chain by horizontal-based cooperation. The cooperative inter-domain path calculation method decreasesthe mapping load for the master orchestrator and gets the same end-to-end performance.

Improving Centralized Path Calculation Based on Graph Compression

Shortest-path calculation on weighted graphs are an essential operation in computer networks. The performance of such algorithms has become a critical challenge in emerging software-defined networks(SDN),since SDN controllers need to centralizedly perform a shortest-path query for every flow,usually on large-scale network. Unfortunately,one of the challenges is that current algorithms will become incalculable as the network size increases. Therefore, inspired by the compression graph in the field of compute visualization,we propose an efficient shortest path algorithm by compressing the original big network graph into a small one, but the important graph properties used to calculate path is reserved. We implement a centralized version of our approach in SDN-enabled network,and the evaluations validate the improvement compared with the well-known algorithms.

Practical network coding-aware routing protocol for multi-hop wireless networks

Network coding has been considered as one of the effective strategies that improve the throughput of multi- hop wireless networks. In order to effectively apply network coding techniques to the real multi-hop wireless networks, a practical network coding aware routing protocol is proposed in this paper, for unicast sessions in multi- hop wireless networks. The protocol is based on a novel routing metric design that captures the characteristics of network coding and unicast sessions. To ensure the novel routing mettle can operate with practical and widely available path calculation algorithms, a unique mapping process is used to map a real wireless network to a virtual network. The mapping process ensures that the paths with the biggest coding opportunities will be selected by commonly used path calculation algorithms. Simulation results show that the proposed routing protocol is effective to improve the network throughput.

Link-Vertex Topology Aggregation for Multi-domain Path Computation with Hierarchical PCE Architecture

Inter-domain path computing is one big issue in multi-domain networks. The Hierarchical Path Computing Element (H-PCE) is a semi-central architecture for computing inter-domain path. To facilitate H-PCE in inter-domain path computing, this paper proposed a topology aggregation scheme to abstract the edge nodes and their connected inter-domain link as one vertex to achieve more optimal paths and confidentiality guarantee. The effectiveness of the scheme has been demonstrated on solving wavelength routing in multi-domain Wavelength Division Multiplexing (WDM) network via simulation. Simulation results show that this scheme reduces at least 10% inter-domain blocking probability, compared with the traditional Domain-to-the-Node (DtN) scheme.

Steiner Tree Based Optimal Resource Caching Scheme in Fog Computing

Fog Computing is a new platform that can serve mobile devices in the local area. In Fog Computing, the resources need to be shared or cached in the widely deployed Fog clusters. In this paper, we propose a Steiner tree based caching scheme, in which the Fog servers, when caching resources, first produce a Steiner tree to minimize the total path weight(or cost) such that the cost of resource caching using this tree could be minimized. Then we give a running illustration to show how the Fog Computing works and we compare the traditional shortest path scheme with the proposed one. The outcome shows that the Steiner tree based scheme could work more efficiently.

Method of Dynamic Optimal Rout Calculation in the ＂Smart Clean City＂ Project

A solution of the optimization garbage removal problem in the large cities is suggested. In this paper there is described a system architecture to find time-optimal dynamic route for garbage trucks within ＂Smart Clean City＂ project which unites an approach to put special electronic devices on the garbage containers with the developed software responsible for the detecting the filled up containers and building the optimal way to collect the garbage. There is proposed a formal mathematical model of the task of dynamic optimal route and formal the optimization criterion for time-optimal garbage collection of all waste from landfills. The system includes the knowledge base which contains the rule describing the expert knowledge of the city traffic situation.

Multi-path planning algorithm based on fitness sharing and species evolution

A new algorithm is proposed for underwater vehicles multi-path planning. This algorithm is based on fitness sharing genetic algorithm, clustering and evolution of multiple populations, which can keep the diversity of the solution path, and decrease the operating time because of the independent evolution of each subpopulation. The multi-path planning algorithm is demonstrated by a number of two-dimensional path planning problems. The results show that the multi-path planning algorithm has the following characteristics: high searching capability, rapid convergence and high reliability.

Computing All Pairs Shortest Paths on Sparse Graphs with Articulation Points

In most network analysis tools the computation of the shortest paths between all pairs of nodes is a fundamental step to the discovery of other properties. Among other properties is the computation of closeness centrality, a measure of the nodes that shows how central a vertex is on a given network. In this paper, the authors present a method to compute the All Pairs Shortest Paths on graphs that present two characteristics： abundance of nodes with degree value one, and existence of articulation points along the graph. These characteristics are present in many real life networks especially in networks that show a power law degree distribution as is the case of biological networks. The authors＇ method compacts the single nodes to their source, and then by using the network articulation points it disconnects the network and computes the shortest paths in the biconnected components. At the final step the authors proposed methods merges the results to provide the whole network shortest paths. The authors＇ method achieves remarkable speedup compared to state of the art methods to compute the shortest paths, as much as 7 fold speed up in artificial graphs and 3.25 fold speed up in real application graphs. The authors＇ performance improvement is unlike previous research as it does not involve elaborated setups since the authors algorithm can process significant instances on a popular workstation.

3D structure parameterization design and modeling for irregular structure of stope bottom

Stope mining design is a very important and complicated task in daily production design and technical management of an underground mine.Based on workface technology and human-computer interaction technology,this study introduces a method of 3D parametric design for the irregular structure of stope bottoms,and focuses on solving technical problems in surface modeling of stope bottom structure.Optimization of the minimum span length algorithm(MSLA) and the shortest path search algorithm(SPSA) is conducted to solve the problem of contour-line based instant modeling of stope bottom structures,which makes possible the 3D parametric design for irregular structure of stope bottom.Implementation process and relevant methods of the proposed algorithms are also presented.Feasibility and reliability of the proposed modeling method are testified in a case study.In practice,the proposed 3 D parameterization design method for irregular structure stope bottom proves to be very helpful to precise 3D parametric design.This method is capable of contributing to improved efficiency and precision of stope design,and is worthy of promotion.

Pattern Formation Control Using QR-Code for Mobile Robots

The article presents multi-pattern formation exchange of mobile robots according to the image signals, programs motion paths using A＊ searching algorithm, and avoids the collision points of motion paths. The system contains an image system, a grid based motion platform, some wireless Radio Frequency （RF） modules and five mobile robots. We use image recognition algorithm to classify variety pattern formation according to variety Quick Response （QR） code symbols on the user interface of the supervised computer. The supervised computer controls five mobile robots to execute formation exchange and presents the movement scenario on the grid based motion platform. We have been developed some pattern formations according to game applications, such as long snake pattern formation, phalanx pattern formation, crane wing pattern formation, sword pattern formation, cone pattern formation, sward pattern tbrmation, T pattern formation, rectangle pattern formation and so on. We develop the user interface of the multi-robot system to program motion paths for variety pattern formation exchange according to the minimum displacement. In the experimental results, the supervised computer recognizes the various QR-code symbols using image system and decides which pattern formation to be selected on real-time. Mobile robots can receive the pattern formation command from the supervised computer, present the movement scenario from the original pattern formation to the assigned pattern formation on the motion platform, and avoid other mobile robots on real-time.

Can hip abduction reduce the risk of femoral head necrosis deteriorated into osteoarthritis?A 3D finite element analysis

The purpose of this study was to investigate biomechanical behavior changes of femoral head necrosis(FHN)by increasing lower extremity abduction(LEA)angle,offering scientific basis on choosing the LEA procedure for the exact classifications.Methods:Thirty computational models were constructed and used to simulate six different abducent angles with five different progresses of FHN.The initial model was validated by the bony density distribution in X-rays images and the photograph of the cadaver bone in cross-section.The stress transfer path(STP)of each model was analyzed and the contact stresses were assessed.Results:During the midstance phase,STP of type A showed strong similarities with the healthy level;STP distribution was from the top of the femoral head to the calcar;the damage area of STP of type B was approximately 25%of the healthy.While STPs in both type C1 and C2 were broken off.As the increase of the abduction angle,STP of type B transformed into type A,STP of type C1 transformed into type B.STP of type C2 transformed into type C1.There was no significant difference in contact stress between the four settings of FHN and normal femoral head.Conclusions:We found computational biomechanical technique to be a sensitive and useful method for distinguishing the biomechanical difference of FHN during abduction gait.These results showed that LEA motion could effectively reduce collapse risk and interrupt the disease pathway of FHN deteriorated into osteoarthritis.Furthermore,our findings indicated that the LEA procedure was suitable for type A,B and C1,while type C2 of FHN involved surgical intervention might get a better clinical outcome.

Path Planning of the Multiple Mobile Robot System Applied in Chinese Chess Game

The article presents the path planning algorithm to be applied in the Chinese chess game, and uses multiple mobile robots to present the experimental scenario. Users play the Chinese chess game using the mouse on the supervised computer. The supervised computer programs the motion paths using A＊ searching algorithm, and controls mobile robots moving on the grid based chessboard platform via wireless radio frequency （RF） interface. The A＊ searching algorithm solves shortest path problems of mobile robots from the start point to the target point, and avoids the obstacles on the chessboard platform. The supervised computer calculates the total time to play the game, and computes the residual time to play chess in the step for each player. The simulation results can fired out the shortest motion paths of the mobile robots （chesses） moving to target points from start points in the monitor, and decides the motion path to be existence or not. The eaten chess can moves to the assigned position, and uses the A＊ searching algorithm to program the motion path, too. Finally, the authors implement the simulation results on the chessboard platform using mobile robots. Users can play the Chinese chess game on the supervised computer according to the Chinese chess game rule, and play each step of the game in the assigned time. The supervised computer can suggests which player don＇t obey the rules of the game, and decides which player to be a winner. The scenario of the Chinese chess game feedback to the user interface using the image system.

Design and Implementation of Agricultural Products Logistics Management System based on WebGIS

The system will be to build a complete logistics monitoring system based on WebGIS, using the development technology of the third party map which is popular at present, the client technology Ajax is introduced into the two map development platform based on WebGIS, draw lessons from the mature MapABC map service interface for API programming, establish the optimization model of distribution route with hard time windows, and studies the application of tabu search algorithm to solve the distribution path optimization model. At the same time, t;he system can realize vehicle abnormal alarm, shortest path planning and analysis of statistical query functions, can display the corresponding curves on the map that query be some statistical analysis results or a heat map by the user, get a more intuitive feel and better user experience.

On the complexity of average path length for biological networks and patterns

Path length calculation is a frequent requirement in studies related to graph theoretic problems such as genetics. Standard method to calculate average path length （APL） of a graph requires traversing all nodes in the graph repeatedly, which is computationally expensive for graphs containing large number of nodes. We propose a novel method to calculate APL for graphs commonly required in the studies of genetics. The proposed method is computationally less expensive and less time-consuming compared to standard method.