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作者： CANSU ALTINTAS MIDDLE EAST TECHNICAL UNIVERSITY

学位级别：硕士

In this thesis, we consider a multi-mode project scheduling problem with a single nonrenewable resource. We assume that the resource is released in pre-specified times at pre-specified quantities and the resource is consumed at activity completions. The activities can be processed at different modes where a mode is defined by a processing time and a resource requirement amount. Our problem is to select the modes and timings of the activities so as to minimize the project completion time. We develop a mixed integer linear model and present a branch and bound algorithm. The results of our experiments have revealed that the mathematical model can handle only small-sized problem instances with up to 20 tasks and branch and bound algorithm can solve problem instances with up to 100 tasks for some resource release profiles.

关键词： Project scheduling Multiple modes Nonrenewable Resource branch and bound algorithm

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The 0-1 Multiple Knapsack Problem

The 0-1 Multiple Knapsack Problem

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作者： Hayat Abdullah Shamakhai Laurentian University

学位级别：硕士

In operation research, the Multiple Knapsack Problem (MKP) is classified as a combinatorial optimization problem. It is a particular case of the Generalized Assignment Problem. The MKP has been applied to many applications in naval as well as financial management. There are several methods to solve the Knapsack Problem (KP) and Multiple Knapsack Problem (MKP); in particular the bound and bound algorithm (B&B). The bound and bound method is a modification of the branch and bound algorithm which is defined as a particular tree-search technique for the integer linear programming. It has been used to obtain an optimal solution. In this research, we provide a new approach called the Adapted Transportation algorithm (ATA) to solve the KP and MKP. The solution results of these methods are presented in this thesis. The Adapted Transportation algorithm is applied to solve the Multiple Knapsack Problem where the unit profit of the items is dependent on the knapsack. In addition, we will show the link between the Multiple Knapsack Problem (MKP) and the multiple Assignment Problem (MAP). These results open a new field of research in order to solve KP and MKP by using the algorithms developed in transportation.

关键词： Generalized Assignment Problem Assignment Problem Knapsack problem Multiple Knapsack Problem branch and bound algorithm bound and bound algorithm Transportation Problem Multiple Assignment Problem Adapted Transportation Problem Vogel Approximation Method Group Role Assignment problem

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Joint Planning of Production and Inspection of Parallel Machines with Two-phase of Failure

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RELIABILITY ENGINEERING & SYSTEM SAFETY 2022年第0期217卷 108097-108097页

作者： Azimpoor, Samareh Taghipour, Sharareh Farmanesh, Babak Sharifi, Mani Ryerson Univ Dept Mech & Ind Engn Reliabil Risk & Maintenance Res Lab RRMR Lab Toronto ON Canada Oklahoma State Univ Dept Ind Engn & Management Stillwater OK USA

Utilizing available information on random machine breakdowns is highly effective in making joint production and inspection decisions. The current paper studies the joint planning of production schedule and inspection of identical parallel machines to process n jobs with different processing times. Each machine's failure is modeled using the two-stage delay time concept. The first stage is a defect arrival which does not cause a machine stoppage, but if it is not removed, may cause the machine failure. A machine's lifetime is divided into two stages in such a failure process: defect arrival and failure arrival stages. The defects and failures of the identical parallel machines follow non-linear and time-dependent distributions. Inspection activities are intended to identify potential defects in the machines and subsequently removing them prior to eventual failures. The objective is to establish the best jobs' schedule of the machines and the best sequence of inspection decisions that minimize the expected makespan. For this problem, unequal defect and failure arrival rates for the machines impose some complications to the expected makespan calculation. Therefore, obtaining an integrated scheduling and inspection plan requires considering all possible combinations of the jobs order and inspections on the machines that further increase the complexity of the algorithm implementation. We propose a branch and bound (B&B) algorithm that restricts the search time and space and demonstrates the effectiveness of integrating inspection and maintenance operations with the jobs sequence to minimize the expected makespan. We propose an upper bound and develop a lower bound to assign the maximum number of jobs on the empty capacity of the machines. We analyze the impact of the model's parameters on the results of the B&B algorithm and validate the algorithm's performance by comparing the results with the analytical solutions for small-sized problems for which analytical solution e

关键词： parallel machines scheduling delay time modelling inspection maintenance branch and bound algorithm

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Řešení lineárních úloh s celočíselnými omezeními v GAMSu

Řešení lineárních úloh s celočíselnými omezeními v...

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作者： Škoda, Štěpán Charles University of Prague

In the present work we study the problems of integer linear optimi- zation, at first from the theoretical point of view (Part I) and subsequently on the basis of empirical data (Part II). First section explains with what this field deals with and where is applied. Other sections contain annotated mathematical formulation of problems, definitions and theorems needed to understand the general methods for solving integer linear programs. In the last section of Part I, we introduce the two best known groups of algorithms that are used by commercial software. The second part provides more details on an Internet library that contains some practical problems, that has been needed to be solved in the past. Furthermore, there are sections dealing with solvers and the advanced options of GAMS. The last section presents data obtained in the course of solving problems using several codes (solvers) of software. 1

关键词： Mixed integer linear problems branch and bound algorithm GAMS solver

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Optimal subcarrier allocation for cognitive radio with multi-user OFDM and distributed antenna

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Journal of Southeast University(English Edition) 2010年第4期26卷 513-517页

作者：葛文栋纪红司鹏搏李曦北京邮电大学泛网无线通信教育部重点实验室北京100876 北京工业大学电子信息与控制工程学院北京100022

The subcarrier allocation problem in cognitive radio（CR）networks with multi-user orthogonal frequency-division multiplexing（OFDM）and distributed antenna is analyzed and modeled for the flat fading channel and the frequency selective channel,where the constraint on the secondary user（SU）to protect the primary user（PU）is that the total throughput of each PU must be above the given threshold instead of the ＂interference temperature＂.According to the features of different types of channels,the optimal subcarrier allocation schemes are proposed to pursue efficiency（or maximal throughput）,using the branch and bound algorithm and the 0-1 implicit enumeration ***,considering the tradeoff between efficiency and fairness,the optimal subcarrier allocation schemes with fairness are proposed in different fading channels,using the pegging *** simulation results illustrate the significant performance improvement of the proposed subcarrier allocation schemes compared with the existing ones in different scenarios.

关键词： cognitive radio subcarrier allocation multi-user OFDM distributed antenna branch and bound algorithm implicit enumeration algorithm pegging algorithm

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Semantic Decomposition By Covering

Semantic Decomposition By Covering

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作者： Sripadham, Shankar B. Virginia Tech | University

This thesis describes the implementation of a covering algorithm for semantic decomposition of sentences of technical patents. This research complements the ASPIN project that has a long term goal of providing an automated system for digital system synthesis from patents. In order to develop a prototype of the system explained in a patent, a natural language processor (sentence-interpreter) is required. These systems typically attempt to interpret a sentence by syntactic analysis (parsing) followed by semantic analysis. Quite often, the technical narrative contains grammatical errors, incomplete sentences, anaphoric references and typological errors that can cause the grammatical parse to fail. In such situations, an alternate method that uses a repository of pre-compiled, simple sentences (called frames) to analyze the sentences of the patent can be a useful back up. By semantically decomposing the sentences of patents to a set of frames whose meanings are fully understood, the meaning of the patent sentences can be interpreted. This thesis deals with the semantic decomposition of sentences using a branch and bound covering algorithm. The algorithm is implemented in C++. A number of experiments were conducted to evaluate the performance of this algorithm. The covering algorithm uses a standard branch and bound algorithm to semantically decompose sentences. The algorithm is fast, flexible and can provide good (100 % coverage for some sentences) coverage results. The system covered 67.68 % of the sentence tokens using 3459 frames in the repository. 54.25% of the frames identified by the system in covers for sentences, were found to be semantically correct. The experiments suggest that the performance of the system can be improved by increasing the number of frames in the repository.

关键词： branch and bound algorithm Linguistic interpretation Covering Sentence interpretation Thesis

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Relaxing Time Windows by Partial Orders in Routing Problems With Stacking Constraints

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IEEE ACCESS 2019年 7卷 139131-139139页

作者： Wei, Chen Hu, Zhi-Hua Gao, Wen-Wen Shanghai Maritime Univ Logist Res Ctr Shanghai 201306 Peoples R China

In vehicle routing problems, time windows are often used to formulate partial order relations between tasks in optimization model and related algorithm. However, time-window and partial order constraints are not equivalent. In the context of stacking operations in container terminals, this study proposed a relaxation method to translate the time-window constraints into the partial order constraints and built a routing optimization model with the partial order constraints. Under the framework of branch and bound (BB) algorithm, this paper studied the relationship between time-window constraints and partial order constraints. The features of the two models are analyzed. The Solomon datasets are used to conduct numerical analysis and examine the differences between the two models in terms of optimization ability and optimality. Revealed by experimental results, the partial-order-based model can be solved with better optimality, while the time-window-based mode can be solved within a shorter time. Moreover, inspired by the effects of narrowing the time windows, it will be a new research direction to develop improved algorithms for partial-order-based model based on time-window-based decomposition method.

关键词： Vehicle routing problem partial order branch and bound algorithm container terminal logistics management

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A Hierarchical Vehicular-Based Architecture for Vehicular Networks: A Case Study on Computation Offloading

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IEEE ACCESS 2020年 8卷 184273-184283页

作者： Liu, Tingting Wang, Junhua Kim, Baekgyu Xie, Jiang Han, Zhu Nanjing Inst Technol Nanjing 211167 Peoples R China Nanjing Univ Aeronaut & Astronaut Sch Comp Sci & Technol Nanjing 211106 Peoples R China Toyota Motor North Amer InfoTech Labs Mountain View CA 94043 USA Univ N Carolina Dept Elect & Comp Engn Charlotte NC 28223 USA Univ Houston Dept Elect & Comp Engn Houston TX 77004 USA Kyung Hee Univ Dept Comp Sci & Engn Seoul 446701 South Korea

In order to realize an intelligent transportation system (ITS) which will provide smooth urban traffic, autonomous driving, accurate route navigation, etc., enormous computations need to be migrated from cloud centers to edge nodes, especially for the services requiring stringent latency. In addition to base stations and road side units (RSUs), vehicles can be alteratively considered as a kind of computation resources. In this article, a hierarchical vehicular-based architecture which consists of cloud centers and vehicles is investigated. Computation offloading performance in the hierarchical architecture is also studied. In specific, the main components in vehicular networks and their characteristics on communication and computations are presented firstly. Several communication techniques that are essential in enabling computation offloading among these components are then discussed. Secondly, a hierarchical vehicular-based architecture, which integrates the main components, is constructed. Thirdly, a case study on computation offloading in the proposed architecture is conducted. In the concerned scenario, the computation offloading problem is modelled as a multi-dimensional multiple knapsack problem (MMKP). Two algorithms are investigated, among which, the first algorithm is a greedy heuristic method providing a sub-optimal solution with a low computational complexity. The second algorithm is a modified branch and bound (B&B) method, which can obtain the best solution with a high computational complexity. Numerical results are also presented to verify the performance of the two algorithms. It can be demonstrated that the proposed architecture can migrate more computations from cloud centers to vehicular nodes, when the computations require more communication resources.

关键词： Computer architecture Task analysis Edge computing Cloud computing Servers Electronic mail Computational modeling Hierarchical vehicular architecture intelligent transportation system computation offloading multi-dimensional multiple knapsack problem branch and bound algorithm

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Collaborative caching strategy based on optimization of latency and energy consumption in MEC

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KNOWLEDGE-BASED SYSTEMS 2021年 233卷

作者： Li, Chunlin Zhang, Yong Sun, Qinqin Luo, Youlong Wuhan Univ Technol Dept Comp Sci Wuhan 430063 Peoples R China Fujian Prov Key Lab Coast & Isl Management Techno Xiamen Peoples R China

Mobile edge computing effectively reduces the network delay of requests during data transmission, reduces the transmission burden of data traffic in the network, and improves the quality of mobile services. However, the introduction of mobile edge computing architecture increases the cost of the actual network infrastructure deployment, which increases the complexity of resource management. An edge network architecture based on software-defined network technology is proposed, in which the SDN controller with the entire network state can manage data transmission more intelligently to maximize the utilization of edge servers. In addition, to solve the problems of high request delay and high operating cost in current caching strategies based on video services, a video caching strategy for mobile edge computing is proposed. First, we analyze the user's request data and use the neural network model to predict the content of the user's subsequent time slice request and pre-cache the user's request. Then, improve the quality of user experience and choose the most appropriate edge node cache deployment plan. Finally, a video caching strategy for mobile edge computing with coordinated optimization of delay and energy consumption is proposed. The branch and bound algorithm is used to solve the optimization problem. Finally, we compared our algorithm with the LFU algorithm, PBC algorithm, COC algorithm, and R-LCCA algorithm. Experimental results show that the algorithm has a high cache hit rate, thereby reducing the cost of video providers and improving the quality of user experience. (c) 2021 Elsevier B.V. All rights reserved.

关键词： Mobile Edge Computing Popularity Prediction Cooperative caching strategy branch and bound algorithm

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Service interruption and customer withdrawal in the congested facility location problem

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TRANSPORTATION RESEARCH PART E-LOGISTICS AND TRANSPORTATION REVIEW 2022年第0期165卷

作者： Zamani, Shokufeh Arkat, Jamal Niaki, Seyed Taghi Akhavan Univ Kurdistan Dept Ind Engn Sanandaj Iran Sharif Univ Technol Dept Ind Engn Tehran Iran

This research addresses the location problem of congested facilities, assuming service in-terruptions and customer withdrawals. Service interruptions can occur as a result of events such as machine failures, power outages, and communication system disconnections. As long as no interruption occurs, each facility functions as a M/M/1 queuing system. Upon an interruption, the server stops working, and customers receiving service or waiting in line leave the queue before being served. Moreover, customers who visit the facility during the repair avoid entering the facility. The problem is first formulated as a mixed-integer nonlinear programming (MINLP) model, for which two piecewise mixed-integer linear programming (MILP) relaxations, an exact solution algorithm (the branch and bound algorithm), and a metaheuristic algorithm (the antlion algorithm), are then presented for solution. Numerical experiments indicate the efficiency of the branch and bound algorithm. The antlion algorithm also exhibits the proper convergence speed to obtain near-optimal solutions.

关键词： Queueing Facility Location Service Interruption Customer Withdrawal branch and bound algorithm

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