检索结果-内蒙古大学图书馆

City-level route planning with time-dependent networks

CURRENT SCIENCE 2020年第4期119卷 680-690页

作者： Kumar, B. Anil Gracious, Rony Gangrade, Chitrak Vanajakshi, Lelitha IIT Patna Dept Civil & Environm Engn Bihta 801103 India Indian Inst Technol Madras Dept Civil Engn Chennai 600036 Tamil Nadu India

The computation of point-to-point shortest paths on time-dependent transportation networks has many practical applications. Finding the shortest path on transportation networks, taking into account prevailing dynamic traffic conditions, can help solve the problem of traffic congestion in urban areas. This study presents a framework for implementation of the shortest path algorithm on static as well as time-dependent city networks to identify the correct match between network complexity, computational requirements and scalability. Dijkstra, bidirectional A*, and A* with landmarks and triangle inequality (ALT) algorithms were selected and implemented based on their reported good performance in earlier studies. The algorithm implementation on both static and dynamic networks was tested on selected networks from Chennai city, India. Among the tested algorithms, ALT performed the best in terms of criteria used in this study. This algorithm is shown to be scalable and can be implemented for any other city network with ease, as demonstrated in this study. The study also discusses techniques for data extraction, cleaning and representation in addition to implementation and comparison of algorithms.

关键词： Dynamic networks shortest path algorithms time-dependent city networks transport planning traffic engineering

来源：评论

学校读者我要写书评

暂无评论

Resource-Considerate Data Routing Through Satellite Networks

引用

JOURNAL OF AEROSPACE INFORMATION SYSTEMS 2017年第8期14卷 472-482页

作者： Lowe, Christopher J. Macdonald, Malcolm Univ Strathclyde Adv Space Concepts Lab 75 Montrose St Glasgow G1 1XJ Lanark Scotland

In many envisaged satellite-based networks, such as constellations or federations, there often exists a desire to reduce data latency, increase delivered data volume, or simply exploit unused resources. A strategy is presented that achieves efficient routing of data, in a store-carry-forward fashion, through satellite networks that exhibit delay- and disruption-tolerant network characteristics. This network-layer protocol, termed Spae, exploits information about the schedule of future contacts between network nodes, because satellite motion is deterministic, along with the capacity of these contacts to route data in such a way as to avoid significant overcommitment of data along a resource-limited journey. Results from simulations of a federated satellite system indicate consistent benefit in terms of network performance over other, less-sophisticated, conventional methods, and comparable performance to a packet-optimal, full-knowledge approach.

关键词： Satellite Networks Satellite Constellations Disruption Tolerant Networking Federated Satellite Systems Network Layer Protocols Constellations shortest path algorithms Buffer Storage Automatic Identification System Satellite Ground Station

来源：评论

学校读者我要写书评

暂无评论

Minimizing mission risk in fuel-constrained unmanned aerial vehicle path planning

引用

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2008年第5期31卷 1497-1500页

作者： Oegren, Petter Winstrand, Maja Swedish Def Res Agcy Dept Autonomous Syst S-16490 Stockholm Sweden

A study was conducted to minimize mission risk in fuel-constrained unmanned aerial vehicle (UAV) path planning. The study showed the way to rewrite the accumulated risk estimate into a form that matches the formulation of the weight-constrained shortest-path problem (WCSPP). An effort was also made to solve the problem approximately, using a series of regular shortest-path problems (SPP). The proposed approach enables planning of missions dealing with multiple threats. The proposed risk-versus-fuel path-planning (RFPP), along with two other path-planning problems have also been stated. The three problems, such as the SPP, the WCSPP, and the risk-versus-fuel path-planning problem are defined. a SPP is formed, in which the cost of the each path segment is calculated, as a linear combination of the path length and the risks involved, to illustrate the standard way of UAV path planning.

关键词： UAV path Planning shortest path algorithms RADAR Autonomous Systems Electronic Warfare

来源：评论

学校读者我要写书评

暂无评论

Improved Dynamic Generation of Operationally Acceptable Reroutes Using Network Optimization

引用

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2011年第4期34卷 961-975页

作者： Taylor, Christine Wanke, Craig Mitre Corp Mclean VA 22102 USA

This paper develops a methodology for generating operationally acceptable reroutes in the presence of convective weather. A decision support system that defines flight-specific reroutes would aid traffic managers in efficiently maneuvering flights, but only if the reroutes provided were acceptable alternatives. As such, this research describes a methodology that captures, through the network definition and metric evaluations, properties of reroutes that are both flexible and operationally acceptable. By employing network optimization techniques, reroutes are developed that can estimate and avoid dynamic weather constraints and do so by optimizing a set of operational acceptability metrics. This paper first illustrates how prioritizing weather avoidance as compared with other cost factors in network generation alters the reroutes generated, which can aid in parameter setting for automation. The reroutes generated through network optimization are then compared with traditional reroute alternatives by evaluating each set of reroutes against a set of operationally acceptable metrics. The overall approach of the proposed methodology is reviewed and details are provided on the modeling formulation and solution algorithm employed by the network optimization method. Multiple flights with weather-impacted routes are examined to show the effectiveness of the proposed methodology in producing reroutes with better operational acceptability.

关键词： Decision Support System shortest path algorithms Cleared Altitude Standard Terminal Arrival Route Standard Instrument Departure Airspace Instrument Flight Rules Corridor Integrated Weather System Dulles International Airport Java Programming Language

来源：评论

学校读者我要写书评

暂无评论

Sequential Traffic Flow Optimization with Tactical Flight Control Heuristics

引用

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2009年第3期32卷 810-820页

作者： Grabbe, Shon Sridhar, Banavar Mukherjee, Avijit NASA Ames Res Ctr Automat Concepts Res Branch Moffett Field CA 94035 USA NASA Ames Res Ctr Aviat Syst Div Moffett Field CA 94035 USA Univ Calif Santa Cruz Moffett Field CA 94035 USA

A sequential optimization method is applied to manage air traffic flow under uncertainty in airspace capacity and demand. To support its testing, a decision support system is developed by integrating a deterministic integer programming model for assigning delays to aircraft under en route capacity constraints with a fast-time simulation environment to reactively account for system uncertainties. To reduce computational complexity, the model assigns only departure controls, and a tactical control loop consisting of a shortest-path routing algorithm and an airbornedelay algorithm refines the strategic plan to keep flights from deviating into capacity-constrained airspace. This integrated approach was used to conduct 32 six-hour fast-time simulation experiments to explore variations in the number and severity of departure controls, tactical reroutes, and airborne-delay controls. These experiments highlighted a fundamental difference in the manner in which weather translation is performed at the strategic and tactical levels. Although tactical weather translation explicitly accounts for the direct impact of weather on individual flights, strategic weather translation, which is accomplished by calculating a reduced capacity fora region of airspace such as a sector, typically fails to account for these flow-based impacts. Finally, an initial validation of the rerouting algorithm, which was the dominant control strategy for avoiding en route weather in the experiments, indicates that the algorithm is able to generate reroutes that are, on average, shorter than operationally flown weather-avoidance routes, when regions of airspace that flights are likely to avoid are identified using the convective-weather-avoidance model.

关键词： Flight Control Airspace Decision Support System Enhanced Traffic Management System Strategic Departure Control Model Air Traffic Control System Command Center Dallas/Fort Worth International Airport shortest path algorithms Federal Aviation Administration Fuel Consumption

来源：评论

学校读者我要写书评

暂无评论

A Multimodal Trip Planning System With Real-Time Traffic and Transit Information

引用

JOURNAL OF INTELLIGENT TRANSPORTATION SYSTEMS 2012年第2期16卷 60-69页

作者： Li, Jing-Quan Zhou, Kun Zhang, Liping Zhang, Wei-Bin Univ Calif Berkeley Calif PATH Richmond CA 94804 USA

Most transit trip planning systems are based on static schedules and generate trips that do not dynamically respond to delays in transit operation caused by traffic congestion or accidents. In addition, the driving-parking-then-transit travel mode is common in metropolitan areas. However, very few transit trip planners incorporate real-time transit data into this mode. This article describes a multimodal trip planning system for multiple modes: driving, transit, and driving-parking-then-transit. The system considers the real-time transit arrival time, which is estimated by a prediction model. Both Web-based and mobile phone-based clients are used to access the system. Case studies show that the multimodal trip planning system works well in real-life situations.

关键词： Database Multimodal Trip Planning Prediction Algorithm shortest path algorithms

来源：评论

学校读者我要写书评

暂无评论

Air Traffic Control Area Configuration Advisories from Near-Optimal Distinct paths

引用

JOURNAL OF AEROSPACE INFORMATION SYSTEMS 2014年第11期11卷 764-784页

作者： Bloem, Michael Bambos, Nicholas NASA Ames Res Ctr Syst Modeling & Optimizat Branch Moffett Field CA 94035 USA Stanford Univ Dept Management Sci Stanford CA 94305 USA Stanford Univ Dept Engn & Elect Engn Stanford CA 94305 USA

Area of specialization supervisors dynamically configure available air traffic control resources so that air traffic can operate safely and efficiently. It is proposed to assist supervisors with this process by presenting them with a set of near-optimal and meaningfully different configuration advisories. To find such a set of advisories, a problem is defined that is equivalent to finding optimal and other near-optimal and distinct paths in a time-expanded graph. It is shown that this problem is nondeterministic polynomial-time hard, and then four algorithms are motivated and specified. One is a benchmark that solves the problem to optimality, one is a novel heuristic based on value iteration, and a third is a novel heuristic based on the A* algorithm. The fourth algorithm solves to optimality the lowest-cost paths problem relaxation of the problem. When used to solve realistic problem instances, the lowest-cost paths algorithm rarely returned feasible solutions and the optimal algorithm required excessive computation times, but the two novel heuristics found feasible and often optimal solutions in just a few seconds. The A* -based heuristic achieved lower computation times, whereas the value iteration-based heuristic typically found more advisories and lower-cost advisories.

关键词： Air Route Traffic Control Center Airspace Federal Aviation Administration shortest path algorithms Human In The Loop RADAR Artificial Intelligence Air Traffic Management Search Algorithm SOFAR

来源：评论

学校读者我要写书评

暂无评论

Finding shortest paths on real road networks: the case for A*

引用

INTERNATIONAL JOURNAL OF GEOGRAPHICAL INFORMATION SCIENCE 2009年第4期23卷 531-543页

作者： Zeng, W. Church, R. L. Univ Calif Santa Barbara Dept Geog Santa Barbara CA 93106 USA China Univ Geosci Fac Informat Engn Wuhan 430074 Peoples R China

The problem of identifying the shortest path along a road network is a fundamental problem in network analysis, ranging from route guidance in a navigation system to solving spatial allocation problems. Since this type of problem is solved so frequently, it is important to craft an approach that is as efficient as possible. Based upon past research, it is generally accepted that several efficient implementations of the Dijkstra algorithm are the fastest at optimally solving the 'one-to-one' shortest path problem (Cherkassky et al. 1996). We show that the most efficient state-of-the-art implementations of Dijkstra can be improved by taking advantage of network properties associated with GIS-sourced data. The results of this paper, derived from tests of different algorithmic approaches on real road networks, will be extremely valuable for application developers and researchers in the GIS community.

关键词： shortest path algorithms A* algorithm Transportation networks

来源：评论

学校读者我要写书评

暂无评论

Optimal cooperative reconnaissance using multiple vehicles

引用

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2007年第1期30卷 122-132页

作者： Ousingsawat, Jarurat Campbell, Mark E. Cornell Univ Sibley Sch Mech & Aerosp Engn Ithaca NY 14853 USA

A study on multivehicle trajectory planning for cooperative reconnaissance problems is presented. Specifically, this work develops understanding and insights into how vehicles cooperate in reconnaissance type missions in which target information is maximized. The performance metric used to guide the cooperation study is the amount of information, defined using the Fisher information matrix, that the sensing vehicles gather over their planned trajectory. A receding horizon optimal control formulation is developed and solved for trajectories that yield maximum information. High-risk zones and vehicle/terminal constraints are also are considered. Trends include the following: 1) vehicles with nonsymmetric sensors tend to triangulate as they get close to the target;2) vehicles tend to move toward stationary targets as quickly as possible;3) the addition of a third vehicle exhibits at least 50% less performance improvement than the addition of the second vehicle, and even less for nonsymmetric sensors.;4) optimization for multiple vehicles and targets is a strong function of target to target distances and sensor uncertainty symmetry;and 5) short planning horizons are preferable for moving targets.

关键词： Sensors Trajectory Optimization Vehicle Trajectories Lagrange Multipliers path Planning shortest path algorithms Boundary Value Problems Mixed Integer Linear Programming Control Optimization Kalman Filter

来源：评论

学校读者我要写书评

暂无评论

Changeability analysis for existing systems

引用

Australian Journal of Multi-Disciplinary Engineering 2020年第1期16卷 43-53页

ABSTRACTABSTRACTChangeability analysis is the practice of assessing a system’s ability to cope with future uncertainties in a broad sense. This paper reviews current changeability analysis methods and techniques and notes that they mostly apply to the design of new systems. Given the state of Australia’s Defence as buyers of off-the-shelf defence assets rather than designers, the state of current changeability analysis methods are assessed for their suitability to meet a set of predefined changeability analysis goals unique to existing systems. Novel extensions are proposed for observed shortfalls in current methods complimented by a theorised discussion of their aptness with application to existing systems. These extensions are intended to form part of future work on this topic.

关键词： Changeability existing systems multi-attribute tradespace exploration tradespace networks epoch era analysis shortest path algorithms

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：