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Measuring the Similarity of Labeled Graphs
 In Proceedings of the Fifth International Conference on CaseBased Reasoning
, 2003
"... This paper proposes a similarity measure to compare cases represented by labeled graphs. We first define an expressive model of directed labeled graph, allowing multiple labels on vertices and edges. ..."
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Cited by 23 (5 self)
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This paper proposes a similarity measure to compare cases represented by labeled graphs. We first define an expressive model of directed labeled graph, allowing multiple labels on vertices and edges.
Hybrid variable neighbourhood approaches to university exam timetabling
, 2006
"... Abstract. In this paper, we investigate variable neighbourhood search (VNS) approaches for the university examination timetabling problem. In addition to a basic VNS method, we introduce variants of the technique with different initialisation methods including a biased VNS and its hybridisation with ..."
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Cited by 14 (9 self)
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Abstract. In this paper, we investigate variable neighbourhood search (VNS) approaches for the university examination timetabling problem. In addition to a basic VNS method, we introduce variants of the technique with different initialisation methods including a biased VNS and its hybridisation with a Genetic Algorithm. A number of different neighbourhood structures are analysed. It is demonstrated that the proposed technique is able to produce high quality solutions across a wide range of benchmark problem instances. In particular, we demonstrate that the Genetic Algorithm, which intelligently selects approporiate neighbourhoods to use within the biased VNS produces the best known results in the literature, in terms of solution quality, on some of the the benchmark instances, although it requires relatively large amount of computational time. Possible extensions to this overall approach are also discussed. 1
Reactive Tabu Search for Measuring Graph Similarity
 In the 5th IAPR Workshop on Graphbased Representations in Pattern Recognition (GbR 2005), LNCS 3434
, 2005
"... Abstract. Graph matching is often used for image recognition. Different kinds of graph matchings have been proposed such as (sub)graph isomorphism or errortolerant graph matching, giving rise to different graph similarity measures. A first goal of this paper is to show that these different measures ..."
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Cited by 12 (4 self)
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Abstract. Graph matching is often used for image recognition. Different kinds of graph matchings have been proposed such as (sub)graph isomorphism or errortolerant graph matching, giving rise to different graph similarity measures. A first goal of this paper is to show that these different measures can be viewed as special cases of a generic similarity measure introduced in [8]. This generic similarity measure is based on a nonbijective graph matching (like [4] and [2]) so that it is well suited to image recognition. In particular, over/undersegmentation problems can be handled by linking one vertex to a set of vertices. In a second part, we address the problem of computing this measure and we describe two algorithms: a greedy algorithm, that quickly computes suboptimal solutions, and a reactive Tabu search algorithm, that may improve these solutions. Some experimental results are given. 1
A Novel Similarity Measure for Heuristic Selection in Examination Timetabling
 In Burke and Trick [13
, 2005
"... Abstract. Metaheuristic approaches to examination timetabling problems are usually split up into two phases: initialisation phase in which a heuristic is employed to construct an initial solution and improvement phase which employs a metaheuristic. Different hybridisations of metaheuristics with seq ..."
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Cited by 12 (1 self)
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Abstract. Metaheuristic approaches to examination timetabling problems are usually split up into two phases: initialisation phase in which a heuristic is employed to construct an initial solution and improvement phase which employs a metaheuristic. Different hybridisations of metaheuristics with sequential heuristics are known to lead to solutions of different quality. A Case Based Reasoning CBR methodology has been developed for selecting an appropriate hybridsation of Great Deluge metaheuristic with a sequential construction heuristic. In this paper we propose a new similarity measure between two timetabling problems that is based on fuzzy sets. The experiments were performed on a number of realworld problems and the results were also compared with other stateoftheart methods. The results obtained show the effectiveness of the developed CBR system. 1
CaseBased Initialisation of Metaheuristics for Examination Timetabling
 Proc. of 1st Multidisciplinary International Conference on Scheduling: Theory and Applications (MISTA 2003
, 2003
"... Examination timetabling problems are traditionally solved by choosing a solution scheme from a plethora of heuristic algorithms based either on direct construction principle or direct construction followed by some incremental improvement procedure. A number of hybrid approaches have also been examin ..."
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Cited by 7 (3 self)
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Examination timetabling problems are traditionally solved by choosing a solution scheme from a plethora of heuristic algorithms based either on direct construction principle or direct construction followed by some incremental improvement procedure. A number of hybrid approaches have also been examined in which a sequential heuristic and a metaheuristic are employed successively. As a rule, best results for a problem instance are obtained by implementing heuristics with domain specific knowledge. However, solutions of this kind are not easily adoptable across different problem classes. To mitigate the need for a problemspecificknowledgebased approach we developed a solution scheme by incorporating case based reasoning methodology. This scheme constructs a solution to a given problem by implementing case based reasoning to select a sequential heuristic, which produces a good initial solution for Great Deluge metaheuristic. By generating a series of computational experiments on benchmark problems we demonstrate that this solution approach gives comparable or better results than solutions generated by stateoftheart approaches based on single Great Deluge Algorithm.
Casebased Selection of Initialisation Heuristics for Metaheuristic Examination Timetabling
"... Examination timetabling problems are often solved by a twophase procedure combining a sequential construction heuristic with a metaheuristic improvement search. There can be many combinations of pairing candidate construction heuristics with a metaheuristic. Different pairings are known to produce ..."
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Cited by 5 (0 self)
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Examination timetabling problems are often solved by a twophase procedure combining a sequential construction heuristic with a metaheuristic improvement search. There can be many combinations of pairing candidate construction heuristics with a metaheuristic. Different pairings are known to produce solutions of varying quality. In this paper we propose a Case Based Reasoning methodology for selecting the pairing of an appropriate sequential construction heuristic with the Great Deluge metaheuristic. We have thoroughly tested our solution approach by using extensive computational experiments in the domain of examination timetabling, and obtained the best results on a number of benchmark problems. In this research we have addressed the research issues of the representation of timetabling problems, similarity measures for timetabling problems, and the retrieval process.
A comparative study of ant colony optimization and reactive search for graph matching problems
 In 6th European Conference on Evolutionary Computation in Combinatorial Optimization (EvoCOP
, 2006
"... Abstract. Many applications involve matching two graphs in order to identify their common features and compute their similarity. In this paper, we address the problem of computing a graph similarity measure based on a multivalent graph matching and which is generic in the sense that other well known ..."
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Cited by 3 (1 self)
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Abstract. Many applications involve matching two graphs in order to identify their common features and compute their similarity. In this paper, we address the problem of computing a graph similarity measure based on a multivalent graph matching and which is generic in the sense that other well known graph similarity measures can be viewed as special cases of it. We propose and compare two different kinds of algorithms: an Ant Colony Optimization based algorithm and a Reactive Search. We compare the efficiency of these two algorithms on two different kinds of difficult graph matching problems and we show that they obtain complementary results. 1
An Investigation Of Casebased Heuristic Selection For University Timetabling
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A Generic Graph Distance Measure Based on Multivalent Matchings
"... Summary. Many applications such as information retrieval and classification, involve measuring graph distance or similarity, i.e., matching graphs to identify and quantify their common features. Different kinds of graph matchings have been proposed, giving rise to different graph similarity or dista ..."
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Summary. Many applications such as information retrieval and classification, involve measuring graph distance or similarity, i.e., matching graphs to identify and quantify their common features. Different kinds of graph matchings have been proposed, giving rise to different graph similarity or distance measures. Graph matchings may be univalent – when each vertex is associated with at most one vertex of the other graph – or multivalent – when each vertex is associated with a set of vertices of the other graph. Also, graph matchings may be exact – when all vertex and edge features must be preserved by the matching – or errortolerant – when some vertex and edge features may not be preserved by the matching. The first goal of this chapter is to propose a new graph distance measure based on the search of a best matching between the vertices of two graphs, i.e., a matching minimizing vertex and edge distance functions. This distance measure is generic in the sense that it allows both univalent and multivalent matchings and it is parameterized by vertex and edge distance functions defined by the user depending on the considered application. The second goal of this chapter is to show how to use this generic measure to model and to solve classical graph matching problems such as (sub)graph isomorphism problem, errortolerant graph matching, and nonbijective graph matching. 1
Use of Case Based Reasoning In Solving Examination Timetabling Problems
"... In an attempt to ensure goodquality printouts of our technical reports, from the supplied PDF files, we process to PDF using Acrobat Distiller. We encourage our authors to use outline fonts coupled with embedding of the used subset of all fonts (in either Truetype or Type 1 formats) except for the ..."
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In an attempt to ensure goodquality printouts of our technical reports, from the supplied PDF files, we process to PDF using Acrobat Distiller. We encourage our authors to use outline fonts coupled with embedding of the used subset of all fonts (in either Truetype or Type 1 formats) except for the standard Acrobat typeface families of Times, Helvetica (Arial), Courier and Symbol. In the case of papers prepared using TEX or LATEX we endeavour to use subsetted Type 1 fonts, supplied by Y&Y Inc., for the Computer Modern, Lucida Bright and Mathtime families, rather than the publicdomain Computer Modern bitmapped fonts. Note that the Y&Y font subsets are embedded under a site license issued by Y&Y Inc. For further details of site licensing and purchase of these fonts visit