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.

This paper focuses on the version models underlying both commercial systems and research prototypes. It provides an overview and classification of different versioning paradigms. Furthermore, it defines and relates fundamental concepts such as revisions, variants, configurations, and changes. In particular, we focus on intensional versioning, i.e., construction of versions based on configuration rules. Finally,we provide an overview of systems whichhave had significant impact on the development of the SCM discipline, and classify them according to a detailed taxonomy

Abstraction is the means by which information can be stored and retrieved from an information structure at different levels of detail and from different perspectives. As such, abstraction mech-anisms in hypertext are interesting to study and, evaluate. In this paper we study the abstraction mechanisms in hypertext born a theoretical perspective. Abstractions then become various first-order logic formulae. Specifically we consider abstractions: sets, sequences, aggregations, generalizations, revisions, and information structures. Interesting results of this work are the definition of level of generality of a hypertext node, the demonstration of revision histories as a partial order, and the notion of compatible-similar nodes. Also defined in this paper is the notion of primitive hypertext3 versus application hypertexts, and the usage of attributes of nodes (illustrated by the use of keywords) across various abskactions. An illustration of the concepts is given using the contexts mechanism suggested by Delisle and Schwartz [DS87]. 1

Most object-oriented languages are objective: an object always responds to the same message in the same way. Subjective objects more closely match naturally occurring systems, and they provide consistent solutions to a wide range of problems, problems that otherwise must be solved by varied and specialized mechanisms. Applying a perspective-receiver symmetry principle in designing the subjectivity semantics of an object-oriented language results in a semantically uncluttered language with a surprisingly wide range of utility. We employ this approach in creating the language Us, a subjective version of Self. 1 Introduction: Subjectivity meets Objects Object-orientation [MMN] wins converts because it can more closely simulate the real world than procedure-oriented programming, yet most object-oriented languages are stuck in a 19-th century, objective stance. A Self or Smalltalk object, for example, always exhibits the same behavior, no matter what the context. But whenever multiple min...

Much of the previous work on version support for hypertext has focused primarily on the development of functionality for specific hypertext systems and/or a specific hypertext ap- plication domain. Although these models address crucial version support problems in specific hypertext application domains, they cannot be easily adapted and then integrated into other hypertext applications. Hypertext version support environments have been introduced to help alleviate these problems. They are designed to meet the version support needs of a wide range of hypertext applications. However, so far few high level versioning facilities have been constructed in these environments, creating a gap between the facilities provided directly within the environment and the versioning needs of some applications. The intent of this research is to bridge this gap. It turned out that task-based versioning styles are easy to use by both hy- pertext application developers and hypertext application users. ...

Object-oriented programming is considered in the context of software communities -- groups of designers and developers sharing knowledge and experience. One way of fostering reuse of this experience is by establishing large collections of reusable object classes. Resulting problems include: ClasspacsOX6/ andcAO7 organization -- how can classes and their methods be represented to simplify reuse. Classselec7X' and exploration -- what query and browsing facilities are needed by developers in order to facilitate software reuse. Class evolution -- how may the class hierarchy be reorganized as a result of changes introduced by developers. These issues are illustrated by examining prototype tools and systems intended to aid object-oriented programming.

The success of large software engineering projects depends critically on the specification, which must represent the requirements of a large number of people with widely differing perspectives. Conventional approaches to software engineering do not address the process of identifying and integrating these perspectives, but instead concentrate on the maintenance of a single consistent description. This results in a specification which represents only one point of view, often the analyst's, excluding suggestions which do not fit with this view. The processes which led to the adoption of this point of view will go unrecorded, making any rationale attached to such a specification incomplete. Other participants will not be able to validate it properly, as it does not relate to their requirements. This thesis integrates ideas drawn from the study of knowledge acquisition, computer-supported co-operative work and negotiation into a model of the specification activity which allows the capture ...

The areas of application of hypermedia technology, combined with the capabilities that hypermedia provides for manipulating structure, create an environment in which version control is very important. A hypermedia version control framework has been designed to specifically address the version control problem in open hypermedia environments. One of the primary distinctions of the framework is the partitioning of hypermedia version control functionality into intrinsic and application-specific categories. The version control framework has been used as a model for the design of version control services for a hyperbase management system that provides complete version support for both data and structural entities. In addition to serving as a version control model for open hypermedia environments, the framework offers a clarifying and unifying context in which to examine the issues of version control in hypermedia.

A rich variety of version models for software configuration management (SCM) has been proposed over the years, and understanding of the basic concepts and their interrelations has been growing accordingly.

Version management is a key function of software configuration management (SCM). A big variety of version models has been realized in both commercial systems and research prototypes. These version models differ with respect to the objects put under version control (files, directories, entitles, objects), the organization of versions (version graphs rs. multi-dimensional version spaces), the granularity of versioning (whole software products rs. individual components), emphasis on states rs. emphasis on changes (staters. change-based versioning), rules for version selection, etc. We present UVM, a Uniform Version Model - and its support architecture - for SCM. Unlike other unification approaches such as e.g. UML for object-oriented modeling, we do not assemble all the concepts having been introduced in previous systems. Instead, we define a base model that is built on a small number of concepts. Specific version models may be expressed in terms of this base model. Our approach