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Exploratory Blockmodeling
Exploratory blockmodeling is an (inductive) approach (or a group of approaches) in blockmodeling regarding the specification of an ideal blockmodel. This approach, also known as hypotheses-generating, is the simplest approach, as it "merely involves the definition of the block types permitted as well as of the number of cluster may refer to: Science and technology Astronomy * Cluster (spacecraft), constellation of four European Space Agency spacecraft * Asteroid cluster, a small asteroid family * Cluster II (spacecraft), a European Space Agency mission to study th ...s." With this approach, researcher usually defines the best possible blockmodel, which then represent the base for the analysis of the whole network. This approach is usually based on: * previous analyses and theoretical considerations, * using stricker blockmodel and block types, where the structural equivalence is stricker than the regular equivalence and * using smaller number of classes. The opposite ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blockmodeling
Blockmodeling is a set or a coherent framework, that is used for analyzing social structure and also for setting procedure(s) for partitioning (clustering) social network's units ( nodes, vertices, actors), based on specific patterns, which form a distinctive structure through interconnectivity. Patrick Doreian, An Intuitive Introduction to Blockmodeling with Examples, ''BMS: Bulletin of Sociological Methodology'' / ''Bulletin de Méthodologie Sociologique'', January, 1999, No. 61 (January, 1999), pp. 5–34. It is primarily used in statistics, machine learning and network science. As an empirical procedure, blockmodeling assumes that all the units in a specific network can be grouped together to such extent to which they are equivalent. Regarding equivalency, it can be structural, regular or generalized. Anuška Ferligoj: Blockmodeling, http://mrvar.fdv.uni-lj.si/sola/info4/nusa/doc/blockmodeling-2.pdf Using blockmodeling, a network can be analyzed using newly created block ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blockmodel
Blockmodel (sometimes also block model) in blockmodeling (part of network science) is defined as a multitude of structures, which are obtained with: * identification of all vertices (e.g., units, nodes) within a cluster and at the same time representing each cluster as a vertex, from which vertices for another graph can be constructed; * combination of all the links (ties), represented in a block as a single link between positions, while at the same time constructing one tie for each block. In a case, when there are no ties in a block, there will be no ties between the two positions, that define the block. In principle, blockmodeling, as a process, is composed from three steps. In the first step, the number of units is determined. This is followed (in the second step) by selection or determination of permitted blocks, that will occur and perhaps also the locations in the matrix. The last, third step, using computer program, the partitioning of units is done, according to the pre- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cluster Analysis
Cluster analysis or clustering is the task of grouping a set of objects in such a way that objects in the same group (called a cluster) are more similar (in some sense) to each other than to those in other groups (clusters). It is a main task of exploratory data analysis, and a common technique for statistical data analysis, used in many fields, including pattern recognition, image analysis, information retrieval, bioinformatics, data compression, computer graphics and machine learning. Cluster analysis itself is not one specific algorithm, but the general task to be solved. It can be achieved by various algorithms that differ significantly in their understanding of what constitutes a cluster and how to efficiently find them. Popular notions of clusters include groups with small distances between cluster members, dense areas of the data space, intervals or particular statistical distributions. Clustering can therefore be formulated as a multi-objective optimization probl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structural Equivalence
Similarity in network analysis occurs when two nodes (or other more elaborate structures) fall in the same equivalence class. There are three fundamental approaches to constructing measures of network similarity: structural equivalence, automorphic equivalence, and regular equivalence.Newman, M.E.J. 2010. ''Networks: An Introduction.'' Oxford, UK: Oxford University Press. There is a hierarchy of the three equivalence concepts: any set of structural equivalences are also automorphic and regular equivalences. Any set of automorphic equivalences are also regular equivalences. Not all regular equivalences are necessarily automorphic or structural; and not all automorphic equivalences are necessarily structural. Visualizing similarity and distance Clustering tools Agglomerative Hierarchical clustering of nodes on the basis of the similarity of their profiles of ties to other nodes provides a joining tree or Dendrogram that visualizes the degree of similarity among cases - and c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Confirmatory Blockmodeling
Confirmatory blockmodeling is a deductive approach in blockmodeling, where a blockmodel (or part of it) is prespecify before the analysis, and then the analysis is fit to this model. When only a part of analysis is prespecify (like individual cluster(s) or location of the block types), it is called ''partially confirmatory blockmodeling''. This is so-called indirect approach, where the blockmodeling is done on the blockmodel fitting (e.g., ''a priori'' hypothesized blockmodel).Aleš Žiberna, ''Generalized blockmodeling of valued networks (pospološeno bločno modeliranje omrežij z vrednostmi na povezavah: doktorska disertacija''. Ljubljana: Univerza v Ljubljani, Fakulteta za družbene vede, 2007. URL: http://www2.arnes.si/~aziber4/blockmodeling/Dissertation-final-corrected.pdf. Opposite approach to the confirmatory blockmodeling is an inductive exploratory blockmodeling Exploratory blockmodeling is an (inductive) approach (or a group of approaches) in blockmodeling regarding t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
