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6th International Conference on Computer Information Systems and Industrial Management Applications

作者： Chaki, Nabendu Chaki, Rituparna Univ Calcutta Kolkata 700009 W Bengal India West Bengal Univ Technol Kolkata 700064 West Bengal India

ISBN: (纸本)9780769528946

An ad-hoc network is a self-supporting collection of mobile nodes that happen to exist within a close proximity in an interval of time. In this paper, a reactive routing protocol has been proposed that computes the shortest path in between any source-destination pair on demand. The approach, unlike other reactive protocols, finds a loop-free, optimal path between the end nodes. It does not use broadcasting like DSR or some other reactive protocols. In fact ORRP exchanges only (n-1) control packets, in the best case. A comparative performance evaluation establishes the advantages of ORRP. The paper is a substantial extension of our earlier work reported in [14].

关键词： mobile ad hoc network routing protocol reactive routing shortest path algorithms loop-free routing

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Online dispatching and routing model for emergency vehicles with area coverage constraints

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NETWORK MODELING 2005 2005年第1923期 1-8页

作者： Yang, SN Hamedi, M Haghani, A Univ Maryland Dept Civil & Environm Engn College Pk MD 20742 USA

Response time plays a crucial role in reducing the loss of assets and lives caused by emergencies. Good dispatch strategics for emergency response vehicles result in more efficient service, and route guidance can help reduce vehicles' travel times. Because of a limited number and type of emergency response vehicles at each station, service area gaps will be created: they cannot be properly covered by the remaining emergency response vehicles when some vehicles are dispatched. Future emergency calls in these areas may experience longer response times than usual. In this paper, an optimization model is developed that, given real-time traffic information, can assist dispatchers of emergency response vehicle in assigning multiple emergency response vehicles to incidents and in determining the routes that avoid congestion spots in the transportation networks. This model accounts for the service area coverage concerns (when several vehicles are busy) by relocation and redistribution of the remaining vehicles among stations. The results show that coordination of different types of vehicles, relocation of vehicles for better area coverage, and use of a time-dependent shortest path algorithm in this model significantly improve the performance of the emergency response system.

关键词： vehicle Coverage Relocation shortest path algorithms system response Route guidance Dispatchers service areas Reaction Time EMERGENCY RESPONSE Emergency Services Emergency vehicles Transport networks Dispatching

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On Integration of Any Factor with Distance for Navigation : Walk Safely and Fast Enough 23

On Integration of Any Factor with Distance for Navigation : ...

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IEEE 23rd International Enterprise Distributed Object Computing Workshop (EDOCW)

作者： Zhao, Yizhou Xie, Yuetian Ahvar, Shohreh ISEP Paris France

ISBN: (纸本)9781728145983

With the popularization of personal navigation systems and mobile devices, multifarious location-based services and datasets are being advanced. In this paper, we propose a new method for navigating based on combination of any factor (e.g. safety, enjoyment, air quality, etc.) with distance. A data structure based on intensity of the factor is introduced. This data structure can be extended easily to cover different sources of data (e.g. government open data, users' feedback). Any kind of shortest path algorithm can be used in proposed method. We apply this method to a situation where travelers are seeking safer routes. The incoming traffic data of each station from Paris in 2017 is utilized to model a location-based safety status of the city. The shortest route is then modulated to a safer route to help pedestrians bypass unsafe zones in the city, thereby reducing the risk of encountering incidents. As a proof-of-concept, we produce a web application based on Google Maps API, which illustrates the performance of our method and application.

关键词： Location-Based Data Navigation Urban Safety Modeling shortest path algorithms

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Finding routes in a public transport network. A case study 19

Finding routes in a public transport network. A case study

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19th International Conference on Methods and Models in Automation and Robotics (MMAR)

作者： Olczyk, Adrian Galuszka, Adam Silesian Tech Univ Inst Automat Control PL-44100 Gliwice Poland

ISBN: (纸本)9781479950812

There is a need for reliable and trustworthy public transport planner services. Mass transits are trying to solve problems as traffic jams or increasing pollution in densely populated city agglomerations. Passengers are looking for travel information on-line and companies providing public transport solutions often struggle with providing modern trip planner platforms. We address this problem by providing simple and easy to implement solution for shortest paths computation in public transport network of any size. In first part of the paper we present our approach to building time-expanded graph model of public transportation network. We use a structure with multiple vertices within one stop identified by triple (stop, time, line) and edges with constant travel times. Second part introduces k-shortest paths algorithm for created graph. We provide step by step explanation along with code samples. Average algorithm response time is around 1.5s for a public transport network of the size over 2800 stops. This is accepted query time for a web application. None additional speed-up techniques has been used to keep implementation and explanations simple and leaving room for further improvements. Algorithm has been successfully tested in Upper Silesian Industrial District (GOP) in cooperation with main public transport provider in the area (KZK GOP). This real instance is the biggest one in Poland and contains 370 lines and over 2800 stops.

关键词： graph theory public transport Upper Silesian Industrial District k-shortest path algorithm mass transit public transport planner service public transportation network time-expanded graph model travel information trip planner platform Data structures Educational institutions Mobile communication Planning Reliability Routing Transportation Travel information Transport networks Public Transit Mass transit public transport network Educational institutions Data structures mobile communication shortest path algorithms Graph theory Network routing transport FINDINGS

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Fast and Efficient Motion Planning using Directional Sampling-based Generalized Shape Expansion

Fast and Efficient Motion Planning using Directional Samplin...

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AIAA Science and Technology Forum and Exposition (AIAA SciTech Forum)

作者： Zinage, Vrushabh Ghosh, Satadal Indian Inst Technol Dept Aerosp Engn Chennai 600036 Tamil Nadu India

ISBN: (数字)9781624106095

ISBN: (纸本)9781624106095

Motion planning is a fundamental area of research in robotics and aerospace applications. Sampling-based methods provide an efficient solution to an otherwise challenging problem in motion planning. Recently, a sampling-based motion planner was presented based on the notion of novel 3D generalized shape to plan for an optimal collision-free path in 3D workspace and was termed as 3D-Generalized Shape Expansion (3D-GSE) algorithm. This was found to exhibit superior performance in terms of computational time and path costs over other wellestablished seminal algorithms in literature. Considering that a suitable directional sampling feature could potentially lead to a further superior performance of the 3D-GSE algorithm, this paper proposes two sampling schemes, namely basic and augmented directional sampling, and presents the 3D-GSE-D and 3D-GSE-AD algorithms, respectively. These algorithms, by default, have the benefits of the 3D-GSE algorithm. In addition, both the basic and augmented directional schemes sample random points with more preference towards the direction of the Goal point leading to lower path cost on average. While the basic directional scheme suffers from a higher computational time when the obstacle density is high along the direction towards the Goal, the augmented directional scheme is free from this drawback. Probabilistic analysis and extensive numerical simulation studies justify the performance of the 3D-GSE-D and the superiority of the 3D-GSE-AD in performance in terms of computational time efficiency and shortest path cost when compared with the 3D-GSE, existing directional and other seminal algorithms.

关键词： Motion Planning Numerical Simulation Robotics Artificial Potential Fields Unmanned Aerial Vehicle shortest path algorithms Mathematical Optimization Proportional Navigation Pseudospectral Methods Autonomous Systems

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Multiple Aircraft Collision Avoidance Method Based on ADS-B System

Multiple Aircraft Collision Avoidance Method Based on ADS-B ...

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AIAA Aviation Forum and Exposition

作者： Zhaoi, Peng Wang, Weichang Ying, Lei Sridhar, Banavar Liu, Yongming Arizona State Univ Sch Engn Matter Transport & Energy Tempe AZ 85281 USA Arizona State Univ Comp & Energy Engn Tempe AZ 85281 USA NASA Ames Res Ctr Univ Space Res Assoc Moffett Field CA 94035 USA

ISBN: (数字)9781624105890

ISBN: (纸本)9781624105890

A new method for multiple aircraft collision avoidance using cost map construction is proposed. The objective of this work is to find a solution to the problem of conflict resolution for multiple ADS-B equipped aircraft. Development of satellite-based navigation technology enables air traffic controller (ATC) and pilot to monitor multiple aircraft in relative long range to the currently used TCAS II system which resolve in last minute. A new conflict resolution scheme is thus developed to avoid collision longer before it happens. In this scheme, a risk map is defined to describe the risk of collision. Based on this map, a cost-minimized trajectory can be found for a single aircraft, using the Dijkstra's algorithm. For the multiple aircraft trajectory planning, the index method is implemented to reduce the computational complexity. Finally, comparison with existing method and several major conclusions are drawn based on the proposed study.

关键词： Commercial Aircraft Air Traffic Controller shortest path algorithms Pilot Aircraft Trajectory Satellites path Planning Restricted Airspace Mid Air Collision Fuel Consumption

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Agent-Based Modeling of Uncrewed Aircraft System Flight Planning for Airspace Fairness

Agent-Based Modeling of Uncrewed Aircraft System Flight Plan...

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AIAA Aviation Forum

作者： Yang, Rebekah Walker, Simone Prebble, Matthew Lesko, Mark Landry, Glen Hales, Shaelynn CNA Corp Ctr Data Management & Analyt Arlington VA 22201 USA

ISBN: (数字)9781624107047

ISBN: (纸本)9781624107047

The number of uncrewed aircraft systems (UAS) and corresponding UAS operations is expected to increase dramatically soon. Regulatory agencies are currently designing and piloting UAS traffic management concepts that rely on federated protocols and a cooperative, community-based approach. As demand increases, the need to ensure fair usage of airspace among operators will be an important challenge. Currently, there are no widely agreed upon definitions or guidelines for UAS airspace fairness. The objective of this work was to evaluate the fairness implications of using a first-filed-first-served protocol for flight planning. We developed UAS Cooperative Airspace Traffic Simulation (UCATS), an agent-based modeling simulation tool, to evaluate different UAS package delivery scenarios using a first-filed-first-served approach to UAS flight planning. We defined key metrics to measure fairness, including average delay, maximum delay, and percentages of flights as planned, replanned, and canceled. Our results showed that a first-filed-first-served approach may cause flights having a departure time later in the day and flights that are filed with less advanced time have a higher probability of experiencing more negative flight outcomes. We also evaluated the sensitivity of fairness metrics to different traffic levels, different flight densities, and the addition of food delivery operations.

关键词： Aircraft Systems Flight Planning Airspace Federal Aviation Administration Air Taxi Conflict Detection and Resolution Department of Transportation shortest path algorithms Air Traffic Management Flight Trajectory

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Flight Radius algorithms 8th

Flight Radius Algorithms

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8th International Conference on Operations Research and Enterprise Systems (ICORES)

作者： Idrissi, Assia Kamal Malapert, Arnaud Jolin, Remi Milanamos Sophia Antipolis France Univ Cote Azur CNRS I3S Nice France

ISBN: (纸本)9789897583520

In this article, we present the flight radius problem (FRP) on the condensed flight network (CFN). Then, giving a specific flight that is defined by an origin and destination (OD) pair, the problem consists in finding routes that connect the OD pair and satisfy a regret constraint on time, distance or cost. The found routes help airline manager to find business opportunities. This problem arises in the real world, for instance in some air transportation companies. The FRP is formulated as finding a maximal subgraph of nodes belonging to routes satisfying a regret constraint. Such routes can be found using shortest paths algorithms (SPA). The CFN is generated using a time-independent approach and stored in the graph database Neo4 j. Implementing SPA in Neo4 j is challenging since the graph database stores the weights of the graph in a separate data structure. In this paper, we propose four methods to solve the FRP: these methods combine parallel and sequential processing with more optimization to overcome time and memory costs. The experimental evaluation demonstrates that the best algorithm is the extended Dijkstra algorithm which meets the real-time constraints of the targeted industrial application.

关键词： Flight Radius Problem Time-independent Model Graph Database shortest path algorithms

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CUDA Solutions for the SSSP Problem

CUDA Solutions for the SSSP Problem

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9th International Conference on Computational Science

作者： Martin, Pedro J. Torres, Roberto Gavilanes, Antonio Univ Complutense Madrid Dpto Sistemas Informat & Computatc E-28040 Madrid Spain

ISBN: (纸本)9783642019692

We present several algorithms that solve the single-source shortest-path problem using CUDA. We have run them on a database, composed of hundreds of large graphs represented by adjacency lists and adjacency matrices, achieving high speedups regarding a CPU implementation based on Fibonacci heaps. Concerning correctness, we outline why our solutions work, and show that a previous approach [10] is incorrect.

关键词： shortest path algorithms GPU CUDA

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Efficient Distance Sensitivity Oracles for Real-World Graph Data 36

Efficient Distance Sensitivity Oracles for Real-World Graph ...

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IEEE 36th International Conference on Data Engineering (ICDE)

作者： Lee, Jong-Ryul Chung, Chin-Wan Korea Adv Inst Sci & Technol KAIST Sch Comp Daejeon South Korea Chongqing Univ Technol CQUT Chongqing Liangjiang KAIST Int Program Chongqing Peoples R China

ISBN: (数字)9781728129037

ISBN: (纸本)9781728129037

A distance sensitivity oracle is a data structure answering queries that ask the shortest distance from a node to another in a network expecting node/edge failures. It has been mainly studied in theory literature, but all the existing oracles for a directed graph suffer from prohibitive preprocessing time and space. Motivated by this, we develop two practical distance sensitivity oracles for directed graphs as variants of Transit Node Routing, and effective speed-up techniques with a slight loss of accuracy. Extensive experiments demonstrate that our oracles greatly outperform all of competitors in most cases. To the best of our knowledge, our oracles are the first distance sensitivity oracles that handle real-world graph data with million-level nodes.

关键词： Graph algorithms path and circuit problems Graphs and networks Distance sensitivity oracle Distance query shortest distance shortest path algorithms

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