NoteCards is a general hypermedia environment designed to help people work with ideas. Its intended users are authors, designers, and other intellectual laborers engaged in analyzing information, designing artifacts, and generally processing ideas. The system provides these users with a variety of hypermedia-based tools for collecting, representing, managing, interrelating, and communicating ideas. This paper presents the NoteCards system as a foil against which to explore some of the major limitations of the current generation of hypermedia systems. In doing so, this paper highlights seven of the major issues that must be addressed in the next generation of hypermedia systems. These seven issues are: search and query, composite nodes, virtual structures, computational engines, versioning, collaborative work, and tailorability. For each of these issues, the papers describes the limitations inherent in NoteCards and the prospects for doing improving the situation in future systems.

We present a model for data organized as graphs. Regular expressions over the types of the node and edge labels are used to qualify connected subgraphs. An algebraic language based on these regular expressions and supporting a restricted form of recursion is introduced. A natural application of this model and its query language is hypertext querying. 1 Introduction Recent database [13, 5] research work shows a growing interest in the definition of graph models and languages to allow a natural way of handling data appearing in applications such as hypertext or geographic database systems. Standard data models are often inefficient as they do not capture the inherent structure of data representing hypertext documents [4, 7, 18] or networks (highways, rivers, : : : ) [12]. In this paper, we present a graph data model. Its application to hypertext querying is illustrated by an example of a travel agency that organizes journeys. We think of a hypertext as a directed labeled graph where t...

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This paper describes an innovative approach to the construction, application and deployment of software factories. Based on experience in creating and evolving the System Factory project at USC, we present a new experimental project, whose technological and organisational objectives are wide-ranging. This effort is called the Distributed System Factory (DSF) project. The DSF project is intended to provide a software infrastructure suitable for engineering large-scale software systems with dispersed teams working over wide-area networks. This software infrastructure is the central focus of this paper. As such, this paper describes the information structures that can be used to model and create the infrastructure, as well as target software applications. It also describes an electronic market-place of logically centralised software services which populate and execute within this infrastructure

Abstract | In this work we discussanumber of issues for the design of hypertext systems in an agent-based model of computation. We examine how the \traditional " fundamental concepts whichare at the basis of the design of hypertexts can be re-visited under a new perspective of collaborative expert agents. The paper presents how some principles of high-level concurrent programming are applied as new methodologies for the design and development of complex software, such ashypertext systems. By adopting an agent-based framework, we gainpowerful control on version management that presents considerable di culties for the developmentofhypertext systems � a general distributed version control mechanism is applied, without signi cant di erences, both in single-user and in collaborative multiuser mode. In both cases, the underlying hypertext architecture is de ned in terms of computational agents interacting each other in order to accomplish common goals. In this paper we present a rst-level prototype implemented in a concurrent object-oriented language, realized on the top of the Common

Although semantic data models provide expressive conceptual modeling mechanisms, they do not support context, i.e. providing controlled partial information on conceptual entities by viewing them from different viewpoints or in different situations. In this paper, we present a model for representing contexts in information bases along with a set of operations for manipulating contexts. These operations support creating, updating, combining, and comparing contexts. Our model contributes to the efficient handling of information, especially in distributed, cooperative environments, as it enables (i) representing (possibly overlapping) partitions of an information base; (ii) partial representations of objects, (iii) flexible naming (e.g. relative names, synonyms and homonyms), (iv) focusing attention, and (v) combining and comparing different partial representations. This work advances towards the development of a formal framework intended to clarify several theoretical and practical issues related to the notion of context. The use of context in a cooperative environment is illustrated through a detailed example. 1.

Interoperability between existing systems, program packages, tools and applications with various degrees of hypermedia awareness is a complex and important challenge facing the hypermedia community. This paper presents a general framework (called the Flag Interoperability Matrix) to discuss and examine hypermedia system interoperability based on the concepts and principles of the Flag taxonomy of open hypermedia systems. The purposes of the Flag Interoperability Matrix are to provide a framework to classify, describe concisely and compare different approaches to hypermedia system interoperability, and provide an overview of the design space of hypermedia system interoperability. The Flag Interoperability Matrix is used to examine existing interoperability approaches. Based on a systematic analysis of possible approaches to hypermedia system interoperability, the paper explores one solution to hypermedia system interoperability that seems particularly promising with respect to handling the growing number of applications with increasing but incomplete awareness of hypermedia structure concepts.

The use of lexical afftnities to help a human requirements analyst find abstractions in problem descriptions is explored. It is hoped that a lexical athnities tinding tool can be used as part of an environment to help organize the sentences and phrases of a natural language problem description to aid the requirements analyst in the extraction of requirements. An experiment to confirm its effectiveness is described. 1.

The notion of context appears in several disciplines, including computer science, under various forms. In this paper, we are concerned with a notion of context in the area of conceptual modeling. First, we present a simple definition whereby a context is seen as a set of objects, within which each object has a set of names and possibly a reference: the reference of the object is another context which "hides" detailed information about the object. Then, we enhance our simple notion of context by structuring its contents through the traditional abstraction mechanisms, i.e. classification, generalization, and attribution. We show that, depending on the application, our notion of context can be used either as an alternative way of modeling or as a complement of the traditional abstraction mechanisms. Finally, we study the interactions between contextualization and the traditional abstraction mechanisms as well as the constraints that govern such interactions.

In information bases following semantic and object-oriented data models logical names are used for the external identification of objects. Yet the naming schemes employed are not "natural" enough and several problems often arise: logical names can be ambiguous, excessively long, unrelated to or unable to follow the changes of the environment of the named object. In natural language, similar problems are resolved by the context within which words are used. An approach to introducing a notion of context in an information base is to provide structuring mechanisms for decomposing it into possibly overlapping parts. This paper focuses on developing a context mechanism for an information base and, in particular, exploiting this mechanism for naming purposes. Rules are developed for generating meaningful names for objects by taking their context into account. This context-based naming enhances name readability, resolves name ambiguities, saves a lot of redundant name substrings, and it locali...