Tatsuo Tsuji

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.

Virtual multimedia objects as the platform of customizing multimedia data

Customizing multimedia data as well as referring its portion is required in multimedia applications. This paper proposes a virtual multimedia object (VMO). This is the object virtually created based on objects in multimedia data. Users can derive portions of multimedia data, append specific data to them, create a new object based on them, and convert their data formats through VMOs. This paper tries to formally describe VMOs. Moreover, a pointing entry is introduced to implement the system based on the concept of VMOs. A pointing entry represents the mappings between a VMO and its original data. Pointing entries are created through user-defined deriving procedures. VMOs are derived through user-defined mapping functions by using the original data and pointing entries. A prototype system using pointing entries has been constructed. Applying it to a multimedia application clarifies that users can manipulate VMOs by writing only a few lines of code, and the mechanism of VMOs gives us a programming guideline.

A flexible kernel data model for bottom-up databases and management of relationships

This paper proposes the kernel data model called a named set model for bottom-up databases. This model represents an element with a triplet of its identifier, its name, and a set of data values and/or elements. This simple structure leads us to be able to represent both of the elements in the DREAM model, which is a data model for a bottom-up database, and the shape, which is the information on the structure of a database. The operators and operations for a set with a name rather than only a set are introduced. The representation of relationships in a bottom-up database is also proposed. The proposed method is to describe the information of relationships as objects. Users can use them in querying and manipulating relationships.

A method of constructing dynamic schema representing the structure of semistructured data

The structure of semistructured data is needed in order to query a large amount of semistructured data, although structure cannot be defined a priori. DataGuides and shape have been proposed to represent the structure of semistructured data. As these can behave as schema from the point of view of representing the structure of data, and are changed according to the existence of objects, these are called dynamic schema. The paper proposes a semi-dynamic construction method for the dynamic schema. The proposed method uses versions of the dynamic schema. Several versions are kept in the system. Each version of the dynamic schema keeps the objects required to construct the next version of it in a list. The correct dynamic schema can easily be constructed by using the versions of dynamic schema and the lists of objects. The performances in deriving the shape, and inserting and deleting objects are experimentally evaluated. Experimental results show that the proposed method is effective in the case where the retrieval occurs more frequently than the deletion.

A storage structure for graph-oriented databases using an array of element types

This paper proposes a storage structure for graph-oriented databases called the flattened separable directory method. In this method, a data representation graph, which is a unit of the represention graph, is primarily represented with an array of edge or node types. As every node or edge can be accessed without navigation, the values of nodes and/or edges can be quickly evaluated. Experimental evaluations support these characteristics, and clarify that the data insertion performance is high, and that less storage overhead is needed for graphs consisting of many node and edge types.