This paper is intended as an investigation of scientific discoveries from a philosophical point of view. In the first half of this century, most of philosophers rather concentrated on the logical analysis of science and set the problem of discovery aside. Logical positivists distinguished a context of discovery from a context of justification and excluded the former from their analysis of scientific theories. Although Popper criticized their inductivism and suggested methodological falsificationism, he also left the elucidation of discovery to psychological inquiries. The problem of scientific discovery was proprely treated for the first time by the "New Philosophy of Science" school in the 1960's. Hanson reevaluated the method of "retroduction" on the basis of Peirce's logical theory and analysed Kepler's astronomical discovery in detail as a typical application of it. Kuhn's theory of paradigm located discoveries in the context of scientific revolutions. Moreover, he paid attention to the function of metaphor in scientific discoveries. Metaphorical use of existing terms and concepts to overcome theoretical difficulties often plays a decisive role in developping new ideas. In the period of scientific revolution, theoretical metaphors can open up new horizons of scientific research by way of juxtapositions of heterogeneous concepts. To explicate such a complicated situation we need the "rhetoric" of science rather than the "logic" of science.

We proposed a graphical user interface (GUI) that provides users with multimedia information, including dynamic images. On the Internet, there are many WWW browsers that read the Hypertext Markup Language (HTML). As various browsers extend the HTML tags and attributes independently to expand and/or improve layout, the HTML compatibility between browsers is lost. We have developed a WWW browser to solve this problem. Our browser presents all multimedia information, including text, images, and dynamic images as a block and renders them without the need to extend the HTML specifications. It independently interprets and draws HTML objects using a layout manager. It has a layout rule, and manages the hierarchical data structure and the block data of HTML documents. This browser also allows layout-rule changes. The layout manager efficiently displays information while checking the available display area size. The structure of this browser is such that the portion that manages the formatting of the document is separated from the portion that displays the individual parts. In this browser, the layout rule allows text to be placed around an image without the need to modify the existing HTML contents. It is also relatively easy to change the presentation of multiple screens, such as a two-page book-like layout or the conventional single-page scroll-bar format by changing the layout rule. The incorporation of media decoders into the browser enables the displaying of various multimedia information, such as sounds, pictures, and moving images.

Portable terminals have the potential of providing information and communication services not only to computer experts at their offices but also to many users being in a variety of daily life situations. The current user interfaces (UIs) of portable terminals are not suitable for a novice user of computers; they require some knowledge on computers from a user. To overcome this problem, the authors tried to implement their knowledge on the daily life in the design of a UI for novice users. As a result, two UI mechanisms, called Novice Interface and Graphical Metaphor Interface, which provide operations, expressions, and data structures in a way similar to those usually used in daily life are proposed. Novice Interface is to provide easy to use environment. It adopts a direct manipulation device with three buttons and a model of data structures, called Small World Model, that limits the number of functions and the depth of hierarchical menu. Graphical Metaphor Interface, being an extension of Novice Interface, is to provide services with a display screen that makes them well-understandable for any user. The proposed UI mechanisms were implemented in a prototype terminal and its software platform. The former offers several applications of the information services (like teleshopping, home banking, or database retrieval) and the communication services (like pen-based image mail, software fax, or telewriting); the latter enables those application programs to provide a consistent UI.

Broadband multimedia information environments are part of the next big advance in communications and computer technology. The use of multimedia infrastructures in offices is becoming very important. This paper deals with a service concept and human interfaces based on a paper metaphor. The proposed service offers the advantages of paper and eliminates the disadvantages. The power of multimedia's expressiveness, user interaction, and hypermedia technology are key points of our solution. We propose a system configuration for implementing the service/human interface.

In the coming information society, people will have to be engaged in the information environment for their everyday activities. We propose a new design concept of Contextual Metaphors for constructing a human interface. It introduces multiple metaphors and makes it easy for people to directly participate into the environment. The major part of the concept is to provide good contextual support for their everyday activities with a layered design of three cognitively distinct concepts. They are the use of everyday based object metaphors, the task oriented assignment of each of metaphors to system functions and the scenario based sequencings of scenes of those metaphors. A prototyping of the concept showed effectiveness of the concept together with some remarks on the actual design.