Graph Mining, Graph Patterns, Social Network, Set & List Valued Attribute, Spatial Data
- 1. Why and What is Graph Mining? • Graphs allows us to model complicated structures • Chemical compounds ( Cheminformatics ) • Protein structures, biological pathways/networks ( Bioinformatics ) • Program control flow, traffic flow and social network analysis • XML documents, the Web and social network analysis • Graph search algorithms have been developed in chemical informatics, computer vision, video indexing and text retrieval. • Graph Mining has become an active and important theme in data mining.
- 2. Graph Patterns • Frequent subgraphs • A subgraph is frequent if its support ( occurrence frequency ) in a given dataset is no less than a minimum support threshold • What is support? • Intuitively the number of transactions containing a single occurrence • Useful for • Characterizing graph sets • Discriminating different groups of graphs • Similarity search in graph databases.
- 3. Methods for Mining Frequent Subgraphs • An Apriori based approach and a pattern-growth approach • Apriori-based algorithms for frequent substructure mining include AGM, FSG, and a path-join method • AGM shares similar characteristics with Apriori-based itemset mining. • FSG and the path-join method explore edges and connections • Pattern Growth Graph Approach is simplistic pattern growth-based frequent substructure mining.
- 4. Social Network • A social network is a heterogeneous and multirelational data set represented by a graph. • Nodes corresponding to objects and edges corresponding to links representing relationships or interactions between objects. • Both nodes and links have attributes. • Social networks need not be social in context. • There are many real-world instances of technological, business, economic, and biologic social networks. • Examples: • Electrical power grids • Telephone call graphs • the spread of computer viruses • the World Wide Web
- 5. Set Valued Attribute • A set-valued attribute may be of homogeneous or heterogeneous type. • A set-valued data can be generalized by: 1. Generalization of each value in the set to its corresponding higher- level concept. 2. Derivation of the general behavior of the set. • Generalization can be performed by applying different generalization operators to explore alternative generalization paths. • The result of generalization is a heterogeneous set.
- 6. Set and Listed Valued Attribute Example • that the hobby of a person is a set-valued attribute containing the set of values Tennis, Hockey, Soccer, Violin. • This set can be generalized to a set of high-level concepts, such as {sports, music, computer games} or into the number 5. • a count can be associated with a generalized value to indicate how many elements are generalized to that value, as in {sports(3),music(1), computer games(1)}, where sports(3) indicates three kinds of sports. and so on.
- 7. Listed Valued Attribute • List-valued attributes can be generalized in a manner similar to that for set-valued attributes except that the order of the elements in the list should be preserved in the generalization. • A list can be generalized according to its general behavior, such as the length of the list, the type of list elements, the value range, the weighted average value for numerical data, or by dropping unimportant elements in the list.
- 8. Listed Valued Attribute Example • List of data for a person’s education record: • “((B.Sc. in Electrical Engineering, U.B.C., Dec., 1998), • (M.Sc. in Computer Engineering, U. Maryland, May, 2001), • (Ph.D. in Computer Science, UCLA, Aug., 2005))”. • We can generalize by dropping less important descriptions (attributes) of each tuple in the list, such as by dropping the month attribute to obtain “((B.Sc., U.B.C., 1998), : : :)”, and/or by retaining only the most important tuple(s) in the list, • Example: “(Ph.D. in Computer Science, UCLA, 2005)”.
- 9. Dimensions in Spatial Data Cube • Three types of dimensions in a spatial data cube: • A nonspatial dimension • A spatial-to-nonspatial dimension • A spatial-to-spatial dimension • A nonspatial dimension contains only nonspatial data. Nonspatial dimensions temperature and precipitation can be constructed for the warehouse. • Example: Contains nonspatial data whose generalizations are nonspatial (such as “hot” for temperature and “wet” for precipitation). • A spatial-to-nonspatial dimension is a dimension whose primitive-level data are spatial but whose generalization, starting at a certain high level, becomes nonspatial.
- 10. Dimensions in Spatial Data Cube • Example: Suppose that the dimension’s spatial representation of Mumbai is generalized to the string “south mumbai.” Although “south mumbai” is a spatial concept, its representation is not spatial. • A spatial-to-spatial dimension is a dimension whose primitive level and all of its high level generalized data are spatial. • Example: the dimension equi temperature region contains spatial data, as do all of its generalizations, such as with regions covering 0-5 degrees (Celsius), 5-10 degree.
- 11. Plan, Plan Database and Plan Mining • A plan consists of a variable sequence of actions. • A plan database or planbase, is a large collection of plans. • Plan mining is the task of mining significant patterns or knowledge from a planbase. • Plan mining can be used to discover travel patterns of business passengers in an air flight database or to find significant patterns from the sequences of actions in the repair of automobiles. • Plan mining is the extraction of important or significant generalized (sequential) patterns from a planbase.
- 12. Spatial Aggregation and Approximation • Aggregation and approximation are especially useful for generalizing attributes with large sets of values, complex structures, and spatial or multimedia data. • We would like to generalize detailed geographic points into clustered regions, such as business, residential, industrial, or agricultural areas, according to land usage. • A multimedia database may contain complex texts, graphics, images, video fragments, maps, voice, music, and other forms of audio/video information. • Generalization on multimedia data can be performed by recognition and extraction of the essential features and/or general patterns of such data. • For an image, the size, color, shape, texture, orientation, and relative positions and structures of the contained objects or regions in the image can be extracted by aggregation and/or approximation. • For a segment of music, its melody can be summarized based on the approximate patterns that repeatedly occur in the segment, while its style can be summarized based on its tone, tempo, or the major musical instruments played.
- 13. • Technologies developed in spatial databases and multimedia databases such as • spatial data accessing and analysis techniques • pattern recognition • image analysis • text analysis • content-based image/text retrieval • multidimensional indexing methods • Example: • Suppose that we have different pieces of land for various purposes of agricultural usage, such as the planting of vegetables, grains, and fruits. These pieces can be merged or aggregated into one large piece of agricultural land by a spatial merge. • However, such a piece of agricultural land may contain highways, houses, and small stores. • If the majority of the land is used for agriculture, the scattered regions for other purposes can be ignored, and the whole region can be claimed as an agricultural area by approximation.