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.

Object-oriented programming is becoming a popular approach to the construction of complex software systems. Benefits of object orientation include support for modular design, code sharing, and extensibility. In order to make the most of these advantages, a type theory for objects and their interactions should be developed to aid checking and

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This paper presents a taxonomy for open hypermedia systems. The purpose of the Flag 1 taxonomy is manifold: #1# to provide a framework to classify and concisely describe individual systems, #2# to characterize what an open hypermedia system is, #3# to provide a framework for comparing di#erent systems in a system independent way, and #4# to provide an overview of the design space of open hypermedia systems.

Frameworks are an object-oriented reuse technique that are widely used in industry but not discussed much by the software engineering research community. They are a way of reusing design that is part of the reason that some object-oriented developers are so productive. This paper compares and contrasts frameworks with other reuse techniques, and describes how to use them, how to evaluate them, and how to develop them. It describe the tradeoffs involved in using frameworks, including the costs and pitfalls, and when frameworks are appropriate.

This paper compares two approaches to meeting the data handling requirements of Intermedia, a hypermedia sysfem developed at fhe institute for Research in information and Scholarship at Brown Universify. Intermedia, though wriffen using an object-oriented programming language, relies on a traditional relafional database management system for data storage and retrieval. We examine the ramifications of replacing the relational database with an object-oriented database. We begin by describing the important characteristics each database system. We then describe Intermedia and give an overview of its architecture and its dafa handling requirements. We explain why and how we used a relational database management system and the problems that we encountered with this system. We then present the design of art objectodenfed database schema for Intermedia and compare the relational and object-oriented dafabase management system approaches. 1. lNTRODUCTlON The Institute for Research in Information and

Database indexing is a well studied problem. However, the advent of Hypertext databases opens new questions in indexing. Searches are often demarcated by pointers between text items. Thus the scope of the search may change dynamically, whereas traditional indexes cover a statically defined region such as a relation. We present techniques for indexing in hypertext databases and com-pare their performance. 1.

ion At present, most distributed object-oriented systems hide communications behind the notion of invocation, i.e. objects invoke other objects with the underlying passing of messages being hidden. However, with the introduction of multimedia objects, it is not possible to hide communications completely. Invocation alone is not sufficient to express the full generalities of a multimedia system. Invocation is sufficient to express the calling of operations on objects. However, invocation cannot naturally describe operations which result in a continuous flow of information, e.g. a play operation on a camera. In general, this situation occurs with all the continuous media types (video, animation, audio, etc). It was therefore necessary to add extra features to the testbench implementation to handle continuous media types. Further details of the extensions can be found in section 4.2.2 below andin# [Coulson,90]. Our implementation of ANSA also includes facilities to create objects in the d...

The World Wide Web has since its beginning provided linking to and from text documents encoded in HTML. The Web has evolved and most Web browsers now support a rich set of media types either by default or by the use of specialised content handlers, known as plug-ins. The limitations of the Web linking model are well known and they also extend into the realm of the other media types currently supported by Web browsers. This paper introduces the Mimicry system that allows authors and readers to link to and from temporal media (video and audio) on the Web. The system is integrated with the Arakne Environment, an open hypermedia integration aimed at Web augmentation.

s are available from the same host in the directory /pub/TR/UBLCS/ABSTRACTS in plain text format. All local authors can be reached via e-mail at the address last-name@cs.unibo.it. UBLCS Technical Report Series 92-1 Mapping Parallel Computations onto Distributed Systems in Paralex, by Ö. Babaoglu, L. Alvisi, A. Amoroso and R. Davoli, January 1992. 92-2 Parallel Scientific Computing in Distributed Systems: The Paralex Approach, by L. Alvisi, A. Amoroso, Ö. Babaoglu, A. Baronio, R. Davoli and L. A. Giachini, February 1992. 92-3 Run-time Support for Dynamic Load Balancing and Debugging in Paralex, by Ö. Babaoglu, L. Alvisi, S. Amoroso, R. Davoli, L. A. Giachini, September 1992. 92-4 Paralex: An Environment for Parallel Programming in Distributed Systems, by Ö. Babaoglu, L. Alvisi, S. Amoroso, R. Davoli, L. A. Giachini, October 1992. 93-1 Consistent Global States of Distributed Systems: Fundamental Concepts and Mechanism, by Ö. Babaoglu and K. Marzullo, January 1993. 93-2 Understanding Non-...