We have presented an approach to automatic document summarization. In the proposed approach, text summarization is modeled as a quadraticinteger-programming problem. This model generally attempts to optimize three pr...
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We have presented an approach to automatic document summarization. In the proposed approach, text summarization is modeled as a quadraticinteger-programming problem. This model generally attempts to optimize three properties, namely, (1) relevance: summary should contain informative textual units that are relevant to the user;(2) redundancy: summaries should not contain multiple textual units that convey the same information;and (3) length: summary is bounded in length. To solve the optimization problem we have created a novel differential evolution algorithm. Experimental results on DUC2005 and DUC2007 data sets showed that the proposed approach outperforms the other methods. Doubt in Title
One approach for analyzing large networks is to partition its nodes into classes where the nodes in a class have similar characteristics with respect to their connections in the network. A class is represented as a bl...
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One approach for analyzing large networks is to partition its nodes into classes where the nodes in a class have similar characteristics with respect to their connections in the network. A class is represented as a blockmodel (or image matrix). In this context, a specific question is to test whether a presumed blockmodel is well reflected in the network or to select from a choice of possible blockmodels the one fitting best. In this paper, we formulate these problems as combinatorial optimization problems. We show that the evaluation of a blockmodel's quality is a generalization of well- known optimization problems such as quadratic assignment, minimum kcut, traveling salesman, and minimum edge cover. A quadratic integer programming formulation is derived and linearized by making use of properties of these special cases. With a branch- and- cut approach, the resulting formulation is solved up to 10,000 times faster than a comparable formulation from the literature.
This paper reports a new formulation of a general hub location model as a quadraticinteger program. Non-convexity of the objective function makes the problem difficult. A variety of alternative solution strategies ar...
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This paper reports a new formulation of a general hub location model as a quadraticinteger program. Non-convexity of the objective function makes the problem difficult. A variety of alternative solution strategies are discussed. Computational results from two simple heuristics are presented for the task of siting 2, 3 or 4 hubs to serve interactions between sets of 10, 15, 20 and 25 U.S. cities. The effects of different computational shortcuts are examined. [ABSTRACT FROM AUTHOR]
A new heuristic method based on tabu search is developed for the problem of locating p interacting hub facilities among n interacting nodes in a network. The method treats equally the problem of locating hub facilitie...
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A new heuristic method based on tabu search is developed for the problem of locating p interacting hub facilities among n interacting nodes in a network. The method treats equally the problem of locating hub facilities, as well as the problem of allocating the nodes to one and only one hub. The algorithm obtained improved solutions to problems from the standard test set from literature which has been used in this study.
This paper develops a decision making tool to support the public decision maker in selecting the optimal energy retrofit interventions on an existing street lighting system. The problem statement is based on a quadrat...
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The traditional assignment problem assumes that the number of persons is equal to that of the tasks, beyond that, one person is allowed to undertake only one task and one task must be accomplished by one person. Howev...
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ISBN:
(纸本)9781467389792
The traditional assignment problem assumes that the number of persons is equal to that of the tasks, beyond that, one person is allowed to undertake only one task and one task must be accomplished by one person. However, in practical situation, a real task usually calls for more than one person, in some cases, those persons are required to work at the same time. If so, the classical assignment model will not be able to describe the problem accurately. In view of this situation, a new generalized assignment model based on nonlinear integerprogramming is presented in this paper. The new model gives a unified description of the generalized assignment problems in which one or more persons are required to work at the same time to complete a single task. As a result, it makes up for the deficiency of the existing generalized assignment model. Moreover, for the case of binary quadraticprogramming, a new branch and bound method is also proposed. The numerical results indicate that the generalized assignment model and method proposed are valid.
The article discusses a quadraticinteger program for the location of interacting hub facilities and the node assignments that minimize the total transportation cost. M.E. O'Kelly has proposed two heuristics, call...
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The article discusses a quadraticinteger program for the location of interacting hub facilities and the node assignments that minimize the total transportation cost. M.E. O'Kelly has proposed two heuristics, called HEUR 1 and HEUR 2, involving a complete enumeration of the locational configurations, and proximity based assumptions about allocation. HEUR 1 involves a complete enumeration of the locational configurations and allocation of every non-hub node to its nearest hub. The objective function of the model developed by O'Kelly involves transportation costs rather than distances. Thus, an explicit assumption in O'Kelly's analysis is that the transportation cost is directly proportional to the distance. The nearest hub assignment is then the same with the least unit transportation cost assignment. Note that this allocation rule may assign a node to different hub facilities if the transportation cost is not directly proportional to the distance. In this case, the nearest hub rule may be totally inappropriate.
Multi-resolution metrology devices co-exist in today's manufacturing environment, producing coordinate measurements complementing each other. Typically, the high-resolution device produces a scarce but accurate da...
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Multi-resolution metrology devices co-exist in today's manufacturing environment, producing coordinate measurements complementing each other. Typically, the high-resolution device produces a scarce but accurate dataset, whereas the low-resolution one produces a dense but less accurate dataset. Research has shown that combining the two datasets of different resolutions makes better predictions of the geometric features of a manufactured part. A challenge, however, is how to effectively match each high-resolution data point to a low-resolution point that measures approximately the same physical location. A solution to this matching problem appears a prerequisite to a good final prediction. This dissertation solves this metrology matching problem by formulating it as a quadratic integer programming, aiming at minimizing the maximum inter-point-distance difference (maxIPDdiff) among all potential correspondences. Due to the combinatorial nature of the optimization model, solving it to optimality is computationally prohibitive even for a small problem size. In order to solve real-life sized problems within a reasonable amount of time, a two-stage matching framework (TSMF) is proposed. The TSMF approach follows a coarse-to-fine search strategy and consists of down-sampling the full size problem, solving the down-sampled problem to optimality, extending the solution of the down-sampled problem to the full size problem, and refining the solution using iterative local search. Many manufactured parts are designed with symmetric features; that is, many part surfaces are invariant (are mapped to themselves) to certain intrinsic reflections and/or rotations. Dealing with parts surfaces with symmetric features makes the metrology matching problem even more challenging. The new challenge is that, due to this symmetry, alignment performance metrics such as maxIPDdiff and root mean square error are not able to differentiate between (a) correct solutions/correspondences that are orie
In this master’s thesis it is discussed the portfolio optimization problem using the passive investment strategy of Index Tracking. The main goals are (i) to present an optimization model for the Index Tracking probl...
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In this master’s thesis it is discussed the portfolio optimization problem using the passive investment strategy of Index Tracking. The main goals are (i) to present an optimization model for the Index Tracking problem and (ii) to solve this model using the heuristic approach of Genetic Algorithms (GA) to create portfolios with reduced amount of stocks. The benchmark used is the Ibovespa Index (main reference for the Brazilian Stock Market), during the period from January/2009 to July/2012 (using a total of 890 daily stock prices). The sample contains 67 assets, and the model is used to build portfolios without limit in the amount of assets and portfolios limited to 40, 30, 20, 10 and 05 assets; the ranges of time to rebalance the portfolios are 20, 40, and 60 trading days, which means to rebalance monthly, bimonthly and quarterly. The results show that, considering this sample, it is not possible to build portfolios with 20 stocks (or less than 20) through direct optimization using the solver Cplex with computational processing time less than 1 hour and results with gap below 5%. On the other hand, using the Genetic Algorithms heuristic approach, portfolios limited to 10 and 05 stocks are built with computational time close to 5 minutes; for both types of portfolio, the solutions provided by the GA have average gap below 10%. Also, with a computational time slightly bigger, close to 8 minutes, the algorithm provides solutions with average gap below 5% for portfolios limited to 10 and 05 stocks. ...
The Slope Conjecture and the Strong Slope Conjecture predict that the degree of the colored Jones polynomial of a knot is matched by the boundary slope and the Euler characteristic of some essential surfaces in the kn...
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The Slope Conjecture and the Strong Slope Conjecture predict that the degree of the colored Jones polynomial of a knot is matched by the boundary slope and the Euler characteristic of some essential surfaces in the knot complement. By solving a problem of quadratic integer programming to find the maximal degree and using the Hatcher-Oertel edgepath system to find the corresponding essential surface, we verify the Slope Conjectures for a family of 3-string Montesinos knots satisfying certain conditions.
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