Bipartite graph partitioning and data clustering

Many data types arising from data mining applications can be modeled as bipartite graphs, examples include terms and documents in a text corpus, customers and purchasing items in market basket analysis and reviewers and movies in a movie recommender system. In this paper, we propose a new data clustering method based on partitioning the underlying bipartite graph. The partition is constructed by minimizing a normalized sum of edge weights between unmatched pairs of vertices of the bipartite graph. We show that an approximate solution to the minimization problem can be obtained by computing a partial singular value decomposition (SVD) of the associated edge weight matrix of the bipartite graph. We point out the connection of our clustering algorithm to correspondence analysis used in multivariate analysis. We also briefly discuss the issue of assigning data objects to multiple clusters. In the experimental results, we apply our clustering algorithm to the problem of document clustering to illustrate its effectiveness and efficiency.Comment: Proceedings of ACM CIKM 2001, the Tenth International Conference on Information and Knowledge Management, 200

Pengkategorian Otomatis Artikel Ilmiah dalam Pangkalan Data Perpustakaan Digital Menggunakan Metode Kernel Graph

Artikel ilmiah dalam pangkalan data perpustakaan digital dikelompokkan dalam kategori-kategori tertentu. Pengelompokan artikel ilmiah dalam jumlah besar yang dilakukan secara manual membutuhkan sumber daya manusia yang banyak dan waktu yang tidak singkat. Penelitian ini bertujuan untuk membantu tim pengolah bahan pustaka dalam mengelompokkan artikel ilmiah sesuai dengan kategorinya masing-masing secara otomatis. Dalam penelitian ini, pengkategorian otomatis artikel ilmiah dilakukan dengan menggunakan kernel graph yang diterapkan pada graph bipartite antara dokumen artikel ilmiah dengan kata kuncinya. Lima fungsi kernel digunakan untuk menghitung nilai matriks kernel, yaitu KEGauss, KELinear, KVGauss, KVLinear dan KRW. Matriks kernel dihitung dari proyeksi satu-moda graph bipartit, lalu digunakan sebagai masukan pengklasifikasi SVM (support vector machine) dalam menentukan kategori yang tepat. Kinerja pengkategorian otomatis dihitung dari ketepatan yang merupakan perbandingan antara jumlah artikel yang dikategorikan secara tepat dengan jumlah keseluruhan artikel dalam dataset. Penerapan metode ini dalam pangkalan data ISJD (Indonesian Scientific Journal Database) menghasilkan rata-rata ketepatan yang signifikan yaitu 87,43% untuk fungsi kernel KVGauss. Sedangkan kernel lainnya memberikan hasil berturut-turut 86,14% (KELinear), 85,86% (KEGauss), 42,23% (KVLinear dan 25,15% (KRW). Hasil ini menunjukkan bahwa penggunaan metode kernel graf efektif untuk mengelompokkan artikel ilmiah ke dalam kategori yang ditentukan dalam pangkalan data perpustakaan digital

K–partitioning of Signed or Weighted Bipartite Graphs

Abstract — In this work, K-partitioning of signed or weighted bipartite graph problem has been introduced, which appears as a real life problem where the partitions of bipartite graph represent two different entities and the edges between the nodes of the partitions represent the relationships among them. A typical example is the set of people and their opinions, whose strength is represented as signed numerical values. Using the weights on the edges, these bipartite graphs can be partitioned into two or more clusters. In political domain, a cluster represents strong relationship among a group of people and a group of issues. In the paper, we formally define the problem and compare different heuristics, and show through both real and simulated data the effectiveness of our approaches

Measuring vertex centrality in co-occurrence graphs for online social tag recommendation

Also published online by CEUR Workshop Proceedings (CEUR-WS.org, ISSN 1613-0073) Proceedings of ECML PKDD (The European Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Databases) Discovery Challenge 2009, Bled, Slovenia, September 7, 2009.We present a social tag recommendation model for collaborative bookmarking systems. This model receives as input a bookmark of a web page or scientific publication, and automatically suggests a set of social tags useful for annotating the bookmarked document. Analysing and processing the bookmark textual contents - document title, URL, abstract and descriptions - we extract a set of keywords, forming a query that is launched against an index, and retrieves a number of similar tagged bookmarks. Afterwards, we take the social tags of these bookmarks, and build their global co-occurrence sub-graph. The tags (vertices) of this reduced graph that have the highest vertex centrality constitute our recommendations, whThis research was supported by the European Commission under contracts FP6-027122-SALERO, FP6-033715-MIAUCE and FP6-045032 SEMEDIA. The expressed content is the view of the authors but not necessarily the view of SALERO, MIAUCE and SEMEDIA projects as a whol

Efficient Mining of Heterogeneous Star-Structured Data

Many of the real world clustering problems arising in data mining applications are heterogeneous in nature. Heterogeneous co-clustering involves simultaneous clustering of objects of two or more data types. While pairwise co-clustering of two data types has been well studied in the literature, research on high-order heterogeneous co-clustering is still limited. In this paper, we propose a graph theoretical framework for addressing star- structured co-clustering problems in which a central data type is connected to all the other data types. Partitioning this graph leads to co-clustering of all the data types under the constraints of the star-structure. Although, graph partitioning approach has been adopted before to address star-structured heterogeneous complex problems, the main contribution of this work lies in an e cient algorithm that we propose for partitioning the star-structured graph. Computationally, our algorithm is very quick as it requires a simple solution to a sparse system of overdetermined linear equations. Theoretical analysis and extensive exper- iments performed on toy and real datasets demonstrate the quality, e ciency and stability of the proposed algorithm