The focus of this article is to develop a map display for to stack in the dark, without knowing what stacks that information retrieval. Through an examination of relationships among visual displays, information retrieval, and browsing, advantages of visual displays for informa-tion retrieval are characterized as (1) the ability to con-we have walked through. We can get a few books each time and walk out of the library to see if the book we are searching for is among them. If not, we have to walk vey a large amount of information in a limited space, (2) in again, based on our knowledge and our previous experi-the potential to reveal semantic relationships of terms ence, to a location where we hope the book would be. In and documents, and (3) the facilitation of browsing and perceptual inferences on retrieval interfaces. These ad-vantages are further demonstrated through a map dis-play generated by a neural network’s self-organizing al-this situation, success in finding a book greatly depends on whether we can walk to the right place in the dark (to generate a good query), and whether we know how to gorithm. The map display detects complex relationships adjust our locations until we get to the right place (to among given documents, and reveals the relationships modify queries interactively). through a spatial arrangement of terms abstracted from Can we turn on the light for such a library? Can we the documents. The map display also provides inter-active tools to allow the user to interact with the underlydevelop some visible cues in our retrieval systems so that ing information. Examples of the map displays show that we can use our perception for information seeking in such map displays can be used both as an overview tool the digital environment? Answers to these questions may and an access or exploration tool, and the map displays will likely increase the amount of information that the user is willing to browse. reside in the recent advance of information technology. ‘‘Information processing has been evolving from numeri-cal computation to character handling, and now to visual information processing’ ’ (Kunii, 1989). As a result, visu-

Wide area networks offer access to an increasing number and variety of resources, such as documents, software, and network services. Yet, it is difficult to locate resources of interest, because of the scale and decentralized nature of the environment. We are interested in supporting a global confederation of loosely cooperating systems and users that share far more resources than can be completely organized. Therefore, mechanisms are needed to support incremental organization of the resources, based on the efforts of many geographically decentralized individuals, and a range of different information sources of varying degrees of quality. In this paper we describe a prototype implementation of a set of mechanisms intended to explore this problem in the specific domain of public Internet archives, accessible via the "anonymous" File Transfer Protocol. This is an interesting test case, because it encompasses a very large scale, administratively decentralized collection of resources, with considerable practical value.

Machine (HAM) and show how several well known systems can be implemented on the standardized hypertext subsystem. The example implements a subset of the HAM using the object-oriented database model presented in this chapter. The class lattice for the hypertext database is given in Figure 8. The classes Boolean, String, Set, and Number should be considered as being predefined by the database management system while all other classes are defined by the hypertext database implementor. The signatures of methods defined by each class are given in Table 1. The classes Node, Link, and Document closely reflect the logical hypertext structure described earlier. However, some implementation details are significant. Since a node may belong to several documents concurrently, the links emanating from it belong to several documents as well. The method links : Node \Theta Doc ! Set returns the set of Table 1: Method signatures for classes of the hypertext database. Name Method Signatures Root Boole...