Recently available low-cost personal computers and mechanisms to produce digital data have caused a staggering increase in the amount of multimedia data acquired by the user. Hence, the user's personal information space that consists of a large collection of files, may distribute over a number of computers. Situation-dependent metaphor methodology, described in this paper, provides a novel approach to managing such a collection with respect to the context of user's interactions with data. By considering the mobile computing environment, the physical location, time periods and activities are primarily used in modeling the situation metaphor. Sensors and software agents are used in capturing contextual factors automatically. Situation Space describes the theoretical foundation for the situation metaphor based information organization. We also presents our prototype engineered model, Situated Information Filing and Filtering (SIFF), to demonstrate the situation-dependent data management. The SIFF provides the framework for organizing the personal information and developing applications that require contextual information.

Conventional database systems are designed for managing textual and numerical data, and retrieving such data is often based on simple comparisons of text/numerical values. However, this simple method of retrieval is no longer adequate for multimedia data, since the digitized representation of images, video, or data itself does not convey the reality of these media items. In addition, composite data consisting of heterogeneous types of data also associates with the semantic content acquired by a user's recognition. Therefore, content-based retrieval for multimedia data is realized taking such intrinsic features of multimedia data into account. Implementation of the content-based retrieval facility is not based on a single fundamental, but is closely related to an underlying data model, a priori knowledge of the area of interest, and the scheme for representing queries. This paper surveys recent studies on content-based retrieval for multimedia databases from the point of view of three fundamental issues. Throughout the discussion, we assume databases that manage only nontextual/numerical data, such as image or video, are also in the category of multimedia databases.

The acceptance of virtual environment (VE) technology requires scrupulous optimization of the most basic interactions in order to maximize user performance and provide efficient and enjoyable virtual interfaces. Motivated by insufficient understanding of the human factors design implications of interaction techniques and tools for virtual interfaces, this paper presents results of a formal study that compared two basic interaction metaphors for egocentric direct manipulation in VEs, virtual hand and virtual pointer, in object selection and positioning experiments. The goals of the study were to explore immersive direct manipulation interfaces, compare performance characteristics of interaction techniques based on the metaphors of interest, understand their relative strengths and weaknesses, and derive design guidelines for practical development of VE applications.

Developing virtual reality (VR) applications which enable actual work over a period of time requires optimization of the most basic interactions, such as object manipulation, so that the immersed participant can concentrate on higher-level tasks rather than on lowlevel motor activities. This paper presents a framework and experimental testbed for studies of VR object manipulation techniques. The framework provides a systematic task analysis of immersive manipulation and suggests a user-specific non-Euclidean system for the measurement of VR spatial relationships. The Virtual Reality Manipulation Assessment Testbed (VRMAT) is a practical implementation of the framework and is a flexible tool allowing in-depth experimental studies of immersive manipulation. Pilot studies have been conducted to evaluate this framework and testbed and to establish a baseline for further development. Keywords: immersive virtual reality, VR user interfaces, VR manipulation techniques, user studies, experimen...

Retrieval is one of the challenging issues in multimedia database studies. Components of multimedia data such as image, video, and audio convey various meaning depending on the standpoint in viewing the data. Deriving the meaning of data, therefore, is not an easy task. At the same time, components of multimedia data inherently possess spatial and/or temporal relationships among them. These two aspects of multimedia data make data retrieval difficult without the support of specific knowledge for the proper interpretation of data and queries. In this paper, we provide an overview of existing approaches related to the issue of implementing content-based retrieval of multimedia databases and then describe a framework for enabling knowledge-assisted retrieval of audio visual content and their spatio-temporal relationship based on user cognition.

The Go-Go immersive interaction technique uses the metaphor of interactively growing the user’s arm and non-linear mapping for reaching and manipulating distant objects. Unlike others, our technique allows for seamless direct manipulation of both nearby objects and those at a distance.

A Cooperative Response system, which can detect and correct users’ misconceptions exhibited in database retrieval, is one of the most promising ways for applying the knowledge engineering approach to traditional database query systems. Misconceptions are generally regarded as users’ false beliefs about a database and are considered as a main source of failures in the database retrieval. How to handle users’ false beliefs has recently become an important point to overcome in advanced database front-end development. While many efforts have been made to develop cooperative response systems, most of the work has placed emphasis on the detection of a user’s false beliefs revealed in a single query. No attention has been paid to handle users’ inconsistent beliefs which would be revealed in a sequence of contextual queries. In this paper, we propose a user-beliefs-modeling approach for detecting the inconsistent beliefs exhibited in two contextual queries. As an extension of the existing cooperative response systems, the system proposed in this paper can generate informative responses to correct users’ inconsistent beliefs.

This paper introduces a generic object which behaves flexibly according to its related objects and conditions for execution in an object-oriented programming system, called ISL-xscheme. A generic object is an instance of 'Generic' class and created by providing abstract classes as a domain. It behaves adequately in the domain depending on its constraints and the messages sent to it. Generic objects are useful for various purposes and applications because they are flexibly transformed via executions depending on what they are used for and how they are used. They are especially effective for program refinement.>

A knowledge-based database assistant (KDA) which integrates a natural language query system with a skeleton-based query guiding facility is provided. When a user works with the KDA natural language query system, the query guiding facility can supply several kinds of skeletons to guide users in performing database retrieval tasks. A semantic network model, S-Net, is introduced to represent the knowledge for natural language query processing and skeleton generation. Methods for implementing the system are discussed.>

An object-oriented data model, MORE, in which the database specification facilities have been extended so that users can specify an object with various structures is presented. The structure of an object is changed by passing messages. MORE also provides a classtype, a user-defined type for classes with similar structures, in order to simplify the specification of class descriptions. The system generates operations useful for the classes by referring to a corresponding classtype. A prototype system and an example application are described.>

A framework for icon management which is quite object-oriented is proposed, and an iconic programming system named HI-VISUAL is presented on the basis of the framework. In the framework, icons represent real objects or concepts already established in a target application environment, whereas icons representing functions are not provided. A function is represented by a combination of two different icons. Each icon can take an active or a passive role against the other. The role sharing is determined dynamically, depending on the environment in which the icons are activated. Programming in HI-VISUAL and implementation issues of the system prototype, now in operation in a laboratory environment, are extensively discussed.>

A knowledge-based database assistant, KDA, is described that has a query-guide function, an SQL-like database query generator, and an interface for subset-English. KDA can be used to design the front end of an SQL database system or a computer-based SQL tutorial system. A method is discussed for transforming a semantic network representing a user's conceptual query into one providing the information required by the system to respond to a query. The query pattern is an expression in natural language representing the semantic structure of concepts. The user expresses queries by filling parentheses in the query patterns with appropriate words. The query-pattern instances thus obtained are then translated into SQL-like relational database queries. The translation is carried out by evaluating operations defined on a semantic network named G-Net which conveys knowledge about application fields, the database schema, and the syntax of SQL.>

User-interface facilities of a map information system HI-MAP that provide visual feedback to the user are presented. The facilities include semantic panning and zooming, overlaying of thematic maps, etc., and are available through an interactive menu system. HI-MAP retrieves map elements in a specified region on the basis of their relevance and their categorical classification. It has a data structure that includes logical and physical hierarchies for the management of semantic relationships and graphic map elements. The software for implementing these facilities is well modularized, and a variety of interfacing modes can be realized by simple communication between modules. The system contributes toward a reduction of the difficulties in obtaining what is really required from databases.>

The authors seek to establish a simple and flexible framework for internal representation of language-dependent information, and the behavior of language-oriented tools for user's operations. They present a system for generating language-oriented editors based on object-oriented concepts. Features of the target language are represented as classes and their relations. A program is represented as an abstract syntax tree. Each node in the tree belongs to a node class. For generating more advanced editors, probes, internal-classes, and gates are incorporated into the system. The system generates a flexible and easily extendable language-oriented editor from a target language description in a highly modularized fashion by using the description language which the system provides.>

The purpose of this study is to construct a system (an Extended Production System, for short, EPS) which selects a desirable strategy dynamically depending on its current state in the process of problem solving. In EPS, a special purpose production interpreter, which directs the system to change its strategies in cooperation with strategic rules, is provided on top of a Conventional Production System (for short, CPS). Furthermore, a set of tactic rules which is appropriate for the strategy is selected from a rulebase and used in order that CPS can restrict search space under the current strategy. This has made EPS capable of following up various problem solving requirements flexibly. A reduction of the number of comparisons between the tactic rules and Short Term Memory (STM) has been attained by declaration of a rule subset appropriate for the strategy in each strategic rule. These advantages have been examined through experiments in image data retrieval by examples.

In ARES, relational operations have been functionally augmented with an additional comparison operator. This operator implies `approximately equal to' or `similar to' for cases in which the user expects the system to perform a flexible interpretation of the query conditions. The functional augmentation is simply achieved by a combination of conventional relational operations. ARES is now in actual operation in a research environment, and will contribute to the next step of research toward implementation of highly intelligent data processing facilities beyond the present scope of database technology.

The authors present an environment which involves a debugging tool to aid in the detection and removal at logic errors. The debugging tool is supported by a special architecture, named SPRING, which was originally developed for reliable execution of Ada or Pascal programs. Following an overview of the system backed up by SPRING, the details of SPRING architecture are described, and the implementation of high level debugging on the SPRING architecture is discussed. In conclusion, the trial could be seen as a step toward providing an advanced programming environment for the development of reliable software.

This paper describes a generic image processing language IPL, and a programming environment supporting the language primitives for an image information system. The central notion of IPL is that it allows the user to navigate through the image database and manipulate images using generalized icons. The image processing language IPL consists of three subsets: the logical image processing language LIPL, the interactive image processing language IIPL, and the physical image processing language PIPL. This paper presents the main concepts of this generic language, some examples, and a scenario.

The relational database system ARES which authors have developed can manage semantic aspects of data to be retrieved, and has two types of relations, namely, conventional and semantic relations. The semantic relation is attached to a conventional relation in terms of a join operation every time a flexible interpretation of queries, accepting a certain amount of ambiguity in query conditions, is required. In order to overcome performance degradation caused by the additional join operation, the authors present an algorithm for parallel execution of a join operation assuming an architecture composed of one master unit and n slave units which are linked to each other. Here, relations are distributed to n slave units by means of hash. According to the static analysis of performances, it is expected that the execution efficiency of a join operation is improved by the extent of o(n) and o(n2) compared with the cases of a single processor using hash for restricting source-target pairs of the subrelations, and that not using hash, respectively. Further investigation, however, is needed in a dynamic environment.

This paper concerns a pyramidal representation of images. The objective of this study is to represent an image with as small a number of data words as possible in a memory without distorting the feature extraction facility inherent in pyramidal representations. First, a novel scheme for simplifying pyramidal representations is presented. Simplification is essentially based on the reduction of the number of informative elements observed in a window space during the hierarchical process of image representation. Following a brief explanation of the window pattern simplification process is a description of an overall procedure for simplifying complex binary images. Finally, for images which are not necessarily binary, procedure for rapid access to and selective use of particular areas and local control of detailed fineness are discussed in conjunction with the architectural considerations for implementing the system.