Teruhisa Hochin

Graph-based data model for the content representation of multimedia data

The contents of multimedia data has complex relationships including deeply nested whole-part and the many-to-many relationships. This paper proposes a data model incorporating the concepts of directed graphs, recursive graphs, and hypergraphs in order to represent the contents of multimedia data. In the proposed data model, an instance is represented with a directed recursive hypergraph called an instance graph. The logic-based operation called rewrite is introduced. It gives us powerful querying capability because regular expressions on paths can be specified in retrieving instance graphs from collection graphs.

Introducing specialization and generalization to a graph-based data model

This paper proposes the schema graph for introducing specialization and generalization to a graph-based data model in order to systematize and reuse knowledge effectively. Systematizing and reusing knowledge are important functions of the knowledge-based human activity. The schema graph enables specialization and generalization relationships to be dynamically added, and removed. The methods of modifying these relationships are precisely presented. The schema graph enables us to systematize and reuse knowledge with keeping the structure flexible.

Impression Evaluation Method Considering the Vagueness of Kansei

This paper proposes a method for evaluating impressions using a space containing impression words. The impression of an object is specified by circling impression words that match the impression. The degree of matching of the impression is expressed by the darkness of the color used to paint the circled area. This proposed method poses few restrictions to users evaluating an impression. Conversely, the semantic differential (SD) method evaluates an impression in a predefined range to enable statistical processing. A prototype system is implemented to evaluate the proposed method, and experimentally compare it with conventional methods, such as the SD method. Finally, it is demonstrated that the proposed method can evaluate aspects that other methods cannot.

Obtaining Factors Describing Impression of Questions and Answers and Estimation of Their Scores from Feature Values of Statements

First, this paper evaluates the impression of questions and answers at Questions and Answers (Q & A) sites in order to avoid the problem of mismatch between the questioner and the respondent. Fifty impression words effective in evaluating impressive expression of statements are selected from a dictionary. An impressive evaluation experiment is then conducted for sixty questions and answers posted at Yahoo! Chiebukuro by using those impression words. Nine factors are obtained by applying factor analysis to the scores obtained through the experiment. Then factor scores of any other statements are tried to be estimated by using multiple regression analysis. This result, however, shows that the estimation accuracy is insufficient. To improve the estimation accuracy, the multiple regression analysis considering quadratic terms is applied. The result of the analysis shows that the estimation accuracy can be improved.

Multimedia data access based on the sensitivity factors

The paper clarifies that the main factors of sensitivity work well for accessing multimedia data. The main factors of sensitivity are the fundamental factors of human sensitivity. These are obtained by applying the factor analysis of the scores put to multimedia data for impression words. Five main factors are obtained for pictures, and four for sounds. Three main factors of sensitivity are in common for pictures and sounds. Substituting the feature values of multimedia data, which are called sensitivity measures, for the factor scores enables a lot of multimedia data to be retrieved through the impression words such as beautiful and fresh. Moreover, the sounds corresponding to a picture can be obtained by evaluating whether the sensitivity measures of sounds are similar to those of the picture. This function is called mixed-media navigation. A prototype system is constructed and evaluated. The evaluation results show that the prototype system can retrieve suitable multimedia data.

Bottom-up scientific databases based on sets and their top-down usage

The paper proposes a data model for a scientific database. Scientific applications require the DBMS support of the discovery process. Unstructured or semi-structured scientific data is required for storage in databases, and manipulation as structured data. To meet these requirements, the proposed data model has the following features. It is based on the concept of sets in order that a database has flexible structure, a perspective of an object is represented with the subset of the object, and a collection of objects are naturally represented. A data value is the principal element for expressing polymorphism and sharing data flexibly. A preliminary database is adopted in order to store unstructured or semi-structured data without any definition. The attribute of data called shape, which varies according to the creation or updating of data, is introduced to query a database. The authors present the application of the model to the archeological data in order to demonstrate its advantages.

Effectiveness of the Analysis Method for the Impression Evaluation Method Considering the Vagueness of Kansei

In recent years, Kansei becomes important. However, the conventional methods are difficult to evaluate Kansei because Kansei is vague. An impression evaluation method considering the vagueness of Kansei has been proposed. This evaluation method makes a subject evaluate impression spatially. A method for analyzing the evaluation results has been proposed and the results of analysis have been shown. This analysis method shows average values and coefficients of variation of scores of the evaluation results spatially. However, only a few subjects joined the evaluation experiment. In this paper, an evaluation experiment is newly conducted, and more evaluation results are obtained. These results are analyzed, and characteristics of the impression of objects and the dispersion among subjects could easily be obtained. It is shown that this analysis method is useful for examining characteristics of impression of objects.

Generation Method of Concurrency Control Program by Using Genetic Programming

This paper proposes a generation system of concurrency control program by using genetic programming (GP). This system generates concurrency control program according to the features of transactions, which are collections of database operations. Functions and terminals of trees representing program in GP, and the fitness measure function used in GP are proposed. The functions and the terminals include those changing and testing variables attached to data items and transactions as well as those checking the kind of operation etc. These will bring us general concurrency control program, which is beyond the combination of the parts of traditional concurrency control program. As the granularity of the functions and the terminals is small, the sub-trees, which are used for the popular concurrency control protocol, and are prepared in advance, are used. The fitness measure function considers the goodness of concurrency control program. The experiments show that a concurrency control program using locks could be generated under the concurrent environment, while a concurrency control program better than the two-phase locking protocol could be generated under the not-so-concurrent environment.

Fast Subsequence Matching in Plasma Waveform Databases

This paper proposes a method of subsequence matching of plasma waveforms. The proposed method divides a waveform into fine-grained segments. The similar segments are grouped into a segment group. A multi-dimensional index is used for quick retrieval. Grouping segments could save the amount of the index. In the retrieval, a sequence of segments, which is called a section, is used as a unit in matching subsequences. Overlapping sections could overcome the shift errors of subsequences, and results in good retrieval correctness.

Extension for Explicit Specification of Semantic Generalization

The semantic generalization and the semantic specialization have been proposed. The semantic generalization makes it possible for a shape graph, which corresponds to a relation schema in the relational data model, to have elements by considering the semantics of the elements of the original shape graphs even if there is no common element in the original ones. The element is the lowest common ancestor of the elements of original shape graphs in a hierarchy of concepts rather than their common element. The semantic specialization enables a shape graph to have elements which are different from those of the original shape graphs, but are semantically related to them. This paper extends the semantic generalization in order that the generalized shape graph can be created according to the users specification. This enables users to create the generalized shape graphs that users want as in the sematic specialization. This extension also brings us unification of the definitions of the semantic generalization and the semantic specialization.