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Intersection traffic deadlock formation and its probability: A petri net-based modeling approach

IET INTELLIGENT TRANSPORT SYSTEMS 2022年第10期16卷 1342-1363页

作者： Qi, HongSheng Yu, Yi Tang, Qing Hu, XianBiao Zhejiang Univ Coll Civil Engn & Architecture Hangzhou Peoples R China Penn State Univ Dept Civil & Environm Engn 212 Sackett Bldg University Pk PA 16801 USA

Although traffic deadlock at an intersection is a common phenomenon during rush hours, the deadlock formation metrics such as formation probability and duration have not been derived yet. As Petri Net (PN)-based approach can formulate the deadlock formation in analytical form and has been applied in numerous traffic flow studies, the PN is employed to investigate the deadlock formation probability and duration. First, each of the four main components of an intersection is formulated, namely vehicle trajectory, traffic signal, vehicle arrivals, and conflict behaviour, as a Petri Net (or IntersectionPN), and name them CellularPN, TrafficLightPN, DemandPN, and ConflictPN, respectively. Together, the entire intersection becomes an IntersectionPN, on which the system's three classes of states are defined, namely the deadlock state, the trap state, and the live state. The deadlock occurrence is formulated as an integer programming problem, while the formation probability and duration are studied by constructing a reachability graph that leads to the Markov chain of the system. A case study shows that the developed model is able to reproduce an intersection deadlock, and that the focus is on two priority behaviours: "First Enter First Serve" and "Pure Stochastic". The results show that different behaviours lead to different deadlock formation metrics and that, when the saturation flow rate degrades (due to events such as severe weather conditions), a deadlock will occur more quickly. The research results provide the analysis tool for probabilistic deadlock formation. It can also be applied to the intersection deadlock prevention and control.

关键词： Markov chain IntersectionPN live state conflict behaviour deadlock state vehicle trajectory traffic information systems deadlock formation probability petri net-based approach integer programming pure stochastic CellularPN ConflictPN trap state rush hours reachability graph integer programming problem road traffic DemandPN Petri nets vehicle arrivals traffic signal TrafficLightPN deadlock occurrence intersection deadlock prevention probability Markov processes reachability analysis intersection traffic deadlock formation probabilistic deadlock formation first enter first serve

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A new model for curriculum-based university course timetabling

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OPTIMIZATION LETTERS 2021年第5期15卷 1601-1616页

作者： Colajanni, Gabriella Daniele, Patrizia Univ Catania Dept Math & Comp Sci Viale A Doria 6 I-95125 Catania Italy

The Curriculum Based university Course Timetabling (CCT) problem consists in determining the best scheduling of university course lessons in a given time interval, assigning the lessons of each course to classrooms and time periods, so that a series of constraints is satisfied. These constraints are divided into two categories: hard constraints, necessary so that the programming can actually be implemented, and soft constraints, which involve qualitative measures. This paper deals with the study of the CCT problem. We formulate a new and complete model that satisfies both the planning constraints and those on the compactness of the curricula, the distribution of the lessons (in the examined time frame), the teachers' preferences, the minimum number of working days, maximum capacity and stability of the classrooms (which aims to minimize the daily movements of students among classrooms) so that the resulting timetable is of high quality. The formulated model, with appropriate adaptations, has been applied to the real case study of the first year of the Mathematics Degree Course of the University of Catania, Italy.

关键词： University course timetable Curriculum based Scheduling integer programming problem

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A novel software-defined networking approach for vertical handoff in heterogeneous wireless networks

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WIRELESS COMMUNICATIONS & MOBILE COMPUTING 2016年第15期16卷 2374-2389页

作者： Qiang, Li Li, Jie Ji, Yusheng Huang, Changcheng Univ Tsukuba Grad Sch Syst & Informat Engn Tsukuba Ibaraki Japan Univ Tsukuba Fac Engn Informat & Syst Tsukuba Ibaraki Japan Natl Inst Informat Informat Syst Architecture Res Div Tokyo Japan Carleton Univ Dept Syst & Comp Engn Ottawa ON Canada

We propose a novel vertical handoff scheme with the support of the software-defined networking technique for heterogeneous wireless networks. The proposed scheme solves two important issues in vertical handoff: network selection and handoff timing. In this paper, the network selection is formulated as a 0-1 integer programming problem, which maximizes the sum of channel capacities that handoff users can obtain from their new access points. After the network selection process is finished, a user will wait for a time period. Only if the new access point is consistently more appropriate than the current access point during this time period, will the user transfer its inter-network connection to the new access point. Our proposed scheme ensures that a user will transfer to the most appropriate access point at the most appropriate time. Comprehensive simulation has been conducted. It is shown that the proposed scheme reduces the number of vertical handoffs, maximizes the total throughput, and user served ratio significantly. Copyright (c) 2016 John Wiley & Sons, Ltd.

关键词： vertical handoff software-defined networking integer programming problem total throughput user served ratio

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Discreet Method to Match Safe Site-Pairs in Short Computation Time for Risk-Aware Data Replication

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IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS 2015年第8期E98D卷 1493-1502页

作者： Nakamura, Takaki Matsumoto, Shinya Muraoka, Hiroaki Tohoku Univ Res Inst Elect Commun Sendai Miyagi 9808577 Japan Hitachi Ltd Yokohama Res Lab Yokohama Kanagawa 2440817 Japan

Risk-aware Data Replication (RDR), which replicates data at primary sites to nearby safe backup sites, has been proposed to mitigate service disruption in a disaster area even after a widespread disaster that damages a network and a primary site. RDR assigns a safe backup site to a primary site while considering damage risk for both the primary site and the backup candidate site. To minimize the damage risk of all site-pairs the integer Programing problem (IPP), which is a mathematical optimization problem, is applied. A challenge for RDR is to choose safe backup sites within a short computation time even for a huge number of sites. As described in this paper, we propose a Discreet method for RDR to surmount this hurdle. The Discreet method first judges the backup sites of a potentially unsafe primary site and avoids assigning a very safe primary site with a very safe backup site. We evaluated the computation time for site-paring and the data availability in the cases of Earthquake and Tsunami using basic disaster simulations. We confirmed that the computation rate of the proposed method is more than 1000 times faster than the existing method when the number of sites is greater than 1000. We also confirmed the data availability of the proposed method;it provides almost equal rates to existing methods of strict optimization. These results mean that the proposed method makes RDR more practical for massively multiple sites.

关键词： remote replication disaster recovery distributed storage integer programming problem availability

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Improving path trimming in a network algorithm for Fisher's exact test in two-way contingency tables

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JOURNAL OF STATISTICAL COMPUTATION AND SIMULATION 2002年第3期72卷 205-216页

作者： Aoki, S Univ Tokyo Grad Sch Informat Sci & Technol Dept Math Informat Bunkyo Ku Tokyo 1130033 Japan

This article provides an improvement of the network algorithm for calculating the exact p value of the generalized Fisher's exact test in two-way contingency tables, We give a new exact upper bound and an approximate upper bound for the maximization problems encountered in the network algorithm, The approximate bound has some very desirable computational properties and the meaning is elucidated from a viewpoint of differential geometry. Our proposed procedure performs well regardless of the pattern of marginal totals of data.

关键词： r x c contingency tables Freeman-Halton test conditional reference set integer programming problem relaxation problem Kultback-Leibler divergence

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Methods of Chebyshev Points of Convex Sets and Their Applications

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COMPUTATIONAL MATHEMATICS AND MATHEMATICAL PHYSICS 2008年第1期48卷 16-29页

作者： Belykh, T. I. Bulatov, V. P. Yas'kova, E. N. Baikal State Univ Econ & Law Irkutsk 664003 Russia Russian Acad Sci Siberian Branch Melentiev Energy Syst Inst Irkutsk 664033 Russia

Chebyshev points of bounded convex sets, search algorithms for them, and various applications to convex programming are considered for simple approximations of reachable sets, optimal control, global optimization of additive functions on convex polyhedra, and integer programming. The problem of searching for Chebyshev points in multicriteria models of development and operation of electric power systems is considered.

关键词： convex programming problem convex sets Chebyshev points integer programming problem

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Algorithms for solving the optimization problems using fuzzy and intuitionistic fuzzy set

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INTERNATIONAL JOURNAL OF SYSTEM ASSURANCE ENGINEERING AND MANAGEMENT 2020年第1期11卷 189-222页

作者： Kumar, P. Senthil Navodaya Inst Technol Dept Humanities & Sci Bijanagera Rd PB 26Navodaya Nagar Raichur 584103 Karnataka India

In this article, the crisp, fuzzy and intuitionistic fuzzy optimization problem is formulated. The basic definitions and notations related to optimization problems are given in the preliminaries section. Algorithms for solving the optimization problems using fuzzy and intuitionistic fuzzy set is presented in this article. Then, with the help of the proposed algorithm the optimal solution of the crisp, fuzzy and intuitionistic fuzzy optimization problems are determined. A new theorem related to type-2 fuzzy/type-2 intuitionistic fuzzy optimization problems is proposed and proved. Some new and concrete results related to type-2 fuzzy/type-2 intuitionistic fuzzy optimization problems are presented. To illustrate the proposed method, some real-life numerical examples are presented. The proposed article provides seven fully worked examples with screenshots of output summaries from the software used in the computations for better understanding. The advantages of the proposed approach as compared to other existing work are also specified. Detail analyses of the comparative study as well the discussion are given. To show the advantages of the proposed approach, superiority analysis is discussed. Comparison analysis and the advantages of the proposed operators are also discussed. Some managerial applications and the advantages of the proposed approach are given. Finally, conclusion and future research directions are also given.

关键词： Fuzzy set Fuzzy number TFN TrFN Intuitionistic fuzzy set Intuitionistic fuzzy number TIFN TrIFN Type-2 FTP Type-2 IFTP Type-2 IFSTP FAP IFAP IFSAP Linear programming method integer programming problem Optimal solution Optimal assignment PSK theorem

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Computing minimal hitting set based on immune genetic algorithm

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INTERNATIONAL JOURNAL OF MODELLING IDENTIFICATION AND CONTROL 2014年第1期21卷 93-100页

作者： Zhou, Gan Feng, Wenquan Jiang, Bofeng Li, Chao Beihang Univ Sch Elect & Informat Engn Beijing 100191 Peoples R China Univ Southern Calif Dept Elect Engn Los Angeles CA 90089 USA

The primary bottleneck of many model-based diagnosis approaches is computing minimal hitting sets (MHSs). Most existing algorithms for computing MHSs are deterministic. Such algorithms are sound and complete but with the complexity of exponential, since the problem of computing MHSs is NP-hard. To reduce the complexity, especially for large systems, we present a novel approach for multiple fault diagnosis, based on an immune genetic algorithm (IGA). This approach maps a hitting set problem onto an integer programming problem, followed by obtaining the lower bound on the size of the solution. The use of the bound in the immune operator guides the MHS search. An elite-set strategy and an appropriate termination criterion are proposed to improve the efficiency of the approach. Experimental results show that our approach solves MHSs faster than the traditional deterministic algorithm in large-scale problems. Compared with the incomplete algorithm, the speed and accuracy of our approach are also significantly improved.

关键词： model-based diagnosis minimal hitting set MHS immune operator elite-set strategy integer programming problem genetic algorithm termination criterion

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Identification of petri nets from knowledge of their language

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DISCRETE EVENT DYNAMIC SYSTEMS-THEORY AND APPLICATIONS 2007年第4期17卷 447-474页

作者： Cabasino, Maria Paola Giua, Alessandro Seatzu, Carla Univ Cagliari Dept Elect & Elect Engn I-09123 Cagliari Italy

In this paper we deal with the problem of identifying a Petri net system, given a finite language generated by it. First we consider the problem of identifying a free labeled Petri net system, i.e., all transition labels are distinct. The set of transitions and the number of places is assumed to be known, while the net structure and the initial marking are computed solving an integer programming problem. Then we extend this approach in several ways introducing additional information about the model (structural constraints, conservative components, stationary sequences) or about its initial marking. We also treat the problem of synthesizing a bounded net system starting from an automaton that generates its language. Finally, we show how the approach can also be generalized to the case of labeled Petri nets, where two or more transitions may share the same label. In particular, in this case we impose that the resulting net system is deterministic. In both cases the identification problem can still be solved via an integer programming problem.

关键词： petri nets identification integer programming problem

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Spectrum Access Strategies Based on the Ratio of Throughput to Spectrum Consumption in the Context of Spectrum Fragmentation in Distributed Cognitive Radio Networks

Spectrum Access Strategies Based on the Ratio of Throughput ...

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IEEE International Conference on Communication Systems (IEEE ICCS)

作者： Zhang, Shuai Lu, Yanhui Wang, Fang Mu, Xiaomin Zhengzhou Univ Sch Infolinat Engn Zhengzhou 450001 Peoples R China Univ Wollongong Sch Elect Comp & Telecommun Wollongong NSW 2522 Australia

ISBN: (纸本)9781479958320

Because of the random presence of primary users in cognitive radio networks, the available spectrums are fragmented with the size of each fragment varying from one channel to several channels. Due to the spectrum fragmentation, the cross-band interference between spectrally adjacent users is considered harmful in the distributed cognitive radio networks. To eliminate the interference, frequency guard-bands are inserted between spectrum fragments. The guard-bands not used for transmission are considered as the spectrum consumption. Accordingly, the achieved throughput is at the cost of the guard-bands consumption. Thus, to utilize the spectrum fragments efficiently, the ratio of throughput to spectrum consumption is defined for the dynamic spectrum access problem. Therefore, under the conditions of prescribed user quality-of-service (QoS) requirements and the frequency agility limit, a novel mathematic model in which the ratio of throughput to spectrum consumption is maximized is proposed in this paper, which is an integer programming problem. To this end, three spectrum access strategies with lower complexities than the traditional exhaustive search are proposed. Simulation results show that the ratio can be used as the index whether the spectrum fragments are effectively utilized. Meanwhile, the spectrum consumption is mainly affected by the size of guard-band, number of fragments and available channels, so the ratios are varying with these factors. Moreover, as the different spectrum utilizations of the four strategies, these factors also have significant influences on the performances of the strategies.

关键词： distributed cognitive radio network spectrum fragmentation guard-band integer programming problem spectrum access strategies

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