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2nd International Asia Conference on Informatics in Control, Automation and Robotics (CAR)

作者： Wang, Hongmei Hu, Ming Xiao, Wei Wang, Hongmei Changchun Univ Technol Sch Comp Sci & Engn Changchun Jilin Peoples R China Jilin Univ Sch Comp Sci & Technol Changchun Jilin Peoples R China

ISBN: (纸本)9781424451944

By studying the best-path problem for public transportation systems, we found that the nature of transfer is that it requires extra costs from an edge to its adjacent edge. Therefore, we propose the notion of direct/indirect adjacent edges in weighted directed multigraphs and extend the notion of path to the line. We use the direct/indirect adjacent edges weighted directed multigraph as a public transportation data model and improve the storage of an adjacency matrix. We introduce the space storage structure, the matrix VL, in order to store the scattered information of transfer in indirect adjacent edges lists. Thus, we solve the problem of complex network graphs' storage and design a new shortest path algorithm to solve transit problem based on the data model we propose in this paper. Algorithm analysis exhibits that the data model and the algorithm we propose are prior to a simple graph based on the Dijkstra's algorithm in terms of time and space.

关键词： direct adjacent edges indirect adjacent edges the vertex-line matrix shortest-path algorithms performance analysis

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Graph-Based Generation and Validation of Use Case Diagrams

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Procedia Computer Science 2025年 259卷 1356-1365页

作者： Reshma P Nair M G Thushara K Somasundaram Department of Computer Science and Engineering Amrita Vishwa Vidyapeetham Amrita School of Computing Amritapuri Kerala India Department of Computer Science and Applications Amrita Vishwa Vidyapeetham Amrita School of Computing Amritapuri Kerala India Department of Mathematics Amrita School of Physical Sciences Amrita Vishwa Vidyapeetham Coimbatore India

As we know in today’s modern software engineering, use case diagrams for representing the functionalities of the system act significantly in mediating the gap between the stakeholder and the developer. Some of the earlier techniques used in constructing such diagrams can be problematic when these diagrams are to be employed in large systems where there are many actors and activities. That is why every limitation outlined above might be resolved further with the help of NLP and developments in graphs theory. The proposed method makes improvements by reducing the human interference; it can handle increase in system size and the number of actors and their interactions; it also provides highly accurate shortest-path identification through use of validation methods. In addition, shortest-path algorithms are incorporated to improve the validation exercise, thereby minimizing errors common in presenting the system functionalities. Hence, the results indicate that the proposed method is more effective not only for generating use case diagrams with increased precision and scalability but also for constructing the necessary framework for checking system interactions’ correctness. This work provides a foundation for future studies aimed at enhancing the automation of the use case diagram especially for complex systems.

关键词： NLP Graph Theory Use case Diagrams Automatic Generation shortest-path algorithms

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Distributed computing approaches for large-scale probit-based stochastic user equilibrium problems

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JOURNAL OF ADVANCED TRANSPORTATION 2013年第6期47卷 553-571页

作者： Liu, Zhiyuan Meng, Qiang Natl Univ Singapore Dept Civil & Environm Engn Singapore 117576 Singapore

Applications of probit-based stochastic user equilibrium (SUE) principle on large-scale networks have been largely limited because of the overwhelming computational burden in solving its stochastic network loading problem. A two-stage Monte Carlo simulation method is recognized to have satisfactory accuracy level when solving this stochastic network loading. This paper thus works on the acceleration of the Monte Carlo simulation method via using distributed computing system. Three distributed computing approaches are then adopted on the workload partition of the Monte Carlo simulation method. Wherein, the first approach allocates each processor in the distributed computing system to solve each trial of the simulation in parallel and in turns, and the second approach assigns all the processors to solve the shortest-path problems in one trial of the Monte Carlo simulation concurrently. The third approach is a combination of the first two, wherein both different trials of the Monte Carlo simulation as well as the shortest path problems in one trial are solved simultaneously. Performances of the three approaches are comprehensively tested by the Sioux-Falls network and then a randomly generated network example. It shows that computational time for the probit-based SUE problem can be largely reduced by any of these three approaches, and the first approach is found out to be superior to the other two. The first approach is then selected to calculate the probit-based SUE problem on a large-scale network example. Copyright (c) 2011 John Wiley & Sons, Ltd.

关键词： probit-based stochastic user equilibrium stochastic network loading Monte Carlo simulation shortest-path algorithms distributed computing

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Detection of core-periphery structure in networks using spectral methods and geodesic paths

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EUROPEAN JOURNAL OF APPLIED MATHEMATICS 2016年第6期27卷 846-887页

作者： Cucuringu, Mihai Rombach, Puck Lee, Sang Hoon Porter, Mason A. Univ Calif Los Angeles Dept Math Los Angeles CA 90024 USA Univ Oxford Math Inst Oxford Ctr Ind & Appl Math Oxford England Korea Inst Adv Study Sch Phys Seoul South Korea Univ Oxford CABDyN Complex Ctr Oxford England

We introduce several novel and computationally efficient methods for detecting "core-periphery structure" in networks. Core-periphery structure is a type of mesoscale structure that consists of densely connected core vertices and sparsely connected peripheral vertices. Core vertices tend to be well-connected both among themselves and to peripheral vertices, which tend not to be well-connected to other vertices. Our first method, which is based on transportation in networks, aggregates information from many geodesic paths in a network and yields a score for each vertex that reflects the likelihood that that vertex is a core vertex. Our second method is based on a low-rank approximation of a network's adjacency matrix, which we express as a perturbation of a tensor-product matrix. Our third approach uses the bottom eigenvector of the random-walk Laplacian to infer a coreness score and a classification into core and peripheral vertices. We also design an objective function to (1) help classify vertices into core or peripheral vertices and (2) provide a goodness-of-fit criterion for classifications into core versus peripheral vertices. To examine the performance of our methods, we apply our algorithms to both synthetically generated networks and a variety of networks constructed from real-world data sets.

关键词： Networks core-periphery structure shortest-path algorithms low-rank matrix approximations graph Laplacians

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Using software complexity measures to analyze algorithms - an experiment with the shortest-paths algorithms

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COMPUTERS & OPERATIONS RESEARCH 2003年第8期30卷 1121-1134页

作者： Nurminen, JK Nokia Res Ctr FIN-00045 Helsinki Finland

In this paper, we apply different software complexity measures to a set of shortest-path algorithms. Our intention is to study what kind of new information about the algorithms the complexity measures (lines-of-code, Halstead's volume, and cyclomatic number) are able to give, to study which software complexity measures are the most useful ones in algorithm comparison, and to analyze when the software complexity comparisons are appropriate. The experiment indicates that the software complexity measures give a new dimension to empirical algorithm comparison. The results explicitly show the trade-off between speed and implementation complexity: a faster algorithm typically requires a more complex implementation. Different complexity measures correlate strongly. Therefore, even the simple lines-of-code measure gives useful results. As the software complexity measures are easy to calculate and since they give useful information, the study suggests that such measures should be included in empirical algorithm comparisons. Unfortunately, for meaningful results, all the algorithms have to be developed in the same fashion which makes the comparison of independent implementations difficult.

关键词： algorithm implementation software complexity measures shortest-path algorithms

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Partial precedence constrained scheduling

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IEEE TRANSACTIONS ON COMPUTERS 1999年第10期48卷 1127-1130页

作者： Chakrabarti, PP Indian Inst Technol Dept Comp Sci & Engn Kharagpur 721302 W Bengal India

This paper presents a generalized formulation of precedence constrained scheduling where the number of dependent tasks which are to be scheduled before the task itself can be scheduled is a variable. This formulation is capable of modeling a number of scheduling and path-finding problems. An algorithm is presented to solve the problem of finding the minimum time schedule. Variants are discussed. One simple variant is shown to be NP-Complete.

关键词： scheduling precedence constraints shortest-path algorithms NP-completeness

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DroplIT, an improved image analysis method for droplet identification in high-throughput crystallization trials

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JOURNAL OF APPLIED CRYSTALLOGRAPHY 2010年第6期43卷 1548-1552页

作者： Vallotton, Pascal Sun, Changming Lovell, David Fazio, Vincent J. Newman, Janet CSIRO CMIS N Ryde NSW 1670 Australia

The application of robotics to protein crystallization trials has resulted in the production of millions of images. Manual inspection of these images to find crystals and other interesting outcomes is a major rate-limiting step. As a result there has been intense activity in developing automated algorithms to analyse these images. The very first step for most systems that have been described in the literature is to delineate each droplet. Here, a novel approach that reaches over 97% success rate and subsecond processing times is presented. This will form the seed of a new high-throughput system to scrutinize massive crystallization campaigns automatically.

关键词： protein crystallization protein crystallography image analysis shortest-path algorithms mathematical morphology automation

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A 3D generalization of user-steered live-wire segmentation

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MEDICAL IMAGE ANALYSIS 2000年第4期4卷 389-402页

作者： Falcao, AX Udupa, JK Univ Penn Dept Radiol Med Image Proc Grp Philadelphia PA 19104 USA Univ Estadual Campinas Inst Comp BR-13083970 Campinas SP Brazil

We have been developing user-steered image segmentation methods for situations which require considerable human assistance in object definition. In the past, we have presented two paradigms, referred to as live-wire and live-lane, for segmenting 2D/3D/4D object boundaries in a slice-by-slice fashion, and demonstrated that live-wire and live-lane are more repeatable, with a statistical significance level of P < 0.03, and are 1.5-2.5 times faster, with a statistical significance level of P < 0.02, than manual tracing. In this paper, we introduce a 3D generalization of the live-wire approach for segmenting 3D/4D object boundaries which further reduces the time spent by the user in segmentation. In a 2D live-wire, given a slice, for two specified points (pixel vertices) on the boundary of the object, the best boundary segment is the minimum-cost path between the two points, described as a set of oriented pixel edges. This segment is found via Dijkstra's algorithm as the user anchors the first point and moves the cursor to indicate the second point. A complete 2D boundary is identified as a set of consecutive boundary segments forming a "closed", "connected", "oriented" contour. The strategy of the 3D extension is that, first, users specify contours via live-wiring on a few slices that are orthogonal to the natural slices of the original scene. If these slices are selected strategically, then we have a sufficient number of points on the 3D boundary of the object to subsequently trace optimum boundary segments automatically in all natural slices of the 3D scene. A 3D object boundary may define multiple 2D boundaries per slice. The points on each 2D boundary form an ordered set such that when the best boundary segment is computed between each pair of consecutive points, a closed, connected, oriented boundary results. The ordered set of points on each 2D boundary is found from the way the users select the orthogonal slices. Based on several validation studies involving segm

关键词： image segmentation boundary detection shortest-path algorithms optimal graph searching active boundaries 3D imaging

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On-line information services in urban integrated transportation networks

On-line information services in urban integrated transportat...

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1997 IEEE Conference on Intelligent Transportation Systems (ITSC 997)

作者： Di Febbraro, A Sacone, S Univ Genoa Dept Commun Comp & Syst Sci I-16145 Genoa Italy

ISBN: (纸本)0780342690

An urban transportation network in which public and private modes-of transport coexist is considered in this paper. The dynamic behaviour of such a network is modelled by means of discrete-event techniques and is reproduced via an ad-hoc realized simulation tool. A major module of the overall simulator consists in an on-line information service able to provide the best intermodal paths between any pair of stations in the network. Such paths vary according to the system dynamics, depending essentially on the traffic conditions. The attention of this work is focused on the heuristic algorithm defined and adopted to search for the required optimal paths.

关键词： discrete-event simulation information systems shortest-path algorithms

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Segmentation of 3D objects using live wire

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Medical Imaging 1997 Symposium - Image Processing

作者： Falcao, AX Udupa, JK Univ. of Pennsylvania Medical Ctr. (United States)

ISBN: (纸本)0819424455

We have been developing user-steered image segmentation methods for situations which require considerable user assistance in object definition. In such situations, our segmentation methods aim (i) to provide effective control to the user on the segmentation process while it is being executed and (ii) to minimize the total user's time required in the process. In the past, we have presented two paradigms, referred to as live wire and live lane, for segmenting 3D/4D object boundaries in a slice-by-slice fashion. In this paper, we introduce a 3D extension of the live wire approach which can further reduce the time spent by the user in the segmentation process. In 2D live wire, given a slice, for two specified points (pixel vertices) on the boundary of the object, the best boundary segment (as a set of oriented pixel edges) is the minimum-cost path between the two points. This segment is found via dynamic programming in real time as the user anchors the first point and moves the cursor to indicate the second point. A complete 2D boundary in this slice is identified as a set of consecutive boundary segments forming a ''closed'', ''connected'', ''oriented'' contour. The strategy of the 3D extension is that, first, users specify contours via live-wiring on a few orthogonal slices. If these slices are selected strategically, then we have a sufficient number of points on the 3D boundary of the object to do live-wiring automatically on all axial slices of the 3D scene. Based on several validation studies involving segmentation of the bones of the foot in MR images, we found that the 3D extension of live wire is statistically significantly (p < 0.0001) more repeatable and 2-6 times faster (p < 0.01) than the 2D live wire method and 3-15 times faster than manual tracing.

关键词： image segmentation boundary detection dynamic programming shortest-path algorithms optimal graph searching active boundaries 3D imaging

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