Weigang Wang

Structured hypertext with domain semantics

One important facet of current hypertext research involves using knowledge-based techniques to develop and maintain document structures. A semantic net is one such technique. However, most semantic-net-based hypertext systems leave the linking consistency of the net to individual users. Users without guidance may accidentally introduce structural and relational inconsistencies in the semantic nets. The relational inconsistency hinders the creation of domain information models. The structural inconsistency leads to unstable documents, especially when a document is composed by computation with traversal algorithms. This work tackles to above problems by integrating logical structure and domain semantics into a semantic net. A semantic-net-based structured-hypertext model has been formalized. The model preserves structural and relational consistency after changes to the semantic net. The hypertext system (RICH) based on this model has been implemented and tested. The RICH system can define and enforce a set of rules to maintain to integrity of the semantic net and provide particular support for creating multihierarchies with the reuse of existing contents and structures. Users have found such flexible but enforceable semantics to be helpful.

Experiences with semantic net based hypermedia

Abstract The Many Using and Creating Hypermedia (MUCH) systems is based on the Dexter model and treats the storage layer as a semantic net. The MUCH system provides a number of recommended link types for representing application domain concepts, such as thesauri, documents, and annotations. Users of the system are expected to use those link types in the course of authoring meaningful hypermedia. This paper is based on the logs of usage of the MUCH system over 2 years by over 200 people. Contrary to the expectations of the builders of the MUCH system, the users did not exploit the ability to type semantic links. Typically authors used the default link type regardless of their semantic intentions. When a link type other than the default type was chosen, that choice was often inconsistent with the way another user would label a similar link. The system has proven to be useful for authoring conventional documents. Authors, however, were not practically able to produce hypertext documents. Based on these experiences a new system, RICH (Reusable Intelligent Collaborative Hypermedia), has been designed and built which emphasizes rules for typing links and maintaining the integrity of the semantic net.

Practitioner and SoftClass: a comparative study of two software reuse research projects

Abstract Software reuse is regarded by many researchers as a key factor to improving software productivity and quality. Software reuse challenges are numerous and require us to rethink the entire spectrum of activities involved in the engineering of software. In this article, we focus on the technical aspects of software reuse, namely, building reusable software, repackaging existing software to make it more readily reusable, and providing computer support for software development with reusable components. We describe two research projects, Practitioner, an ESPRIT-funded collaboration, and SoftClass, a project funded mainly by TANDEM Computers. Both projects attempt to address the above issues, with an emphasis on developing computer tools that support the various reuse activities. The representation of software components is central to both projects. The Practitioner project, which focuses on the early stages of the software life-cycle, has developed tools and representations that support domain analysis activities. SoftClass focuses on the development of representations that lend themselves to computer inferencing for the purposes of supporting design with reusable components. We conclude by summarizing the major technical differences between the projects and discussing other factors that are, in our opinion, equally important to the success of such projects.

Computer-Supported Collaborative Writing Phases

A collaborative hypermedia system was used in a five-week course for computer science students. Authoring tasks were assigned to individuals, groups, and organizations. Students took roles and used the system to perform the tasks. The aim of this research was to see whether collaborative hypermedia systems could improve upon results achieved in traditional collaborative and individual learning environments without a computer. Though technology can support collaboration, the students themselves did not feel positively disposed to sharing their ideas and work with their peers. The group experience did not improve the quality of individual writing. To facilitate group writing, we may want to ensure that the group is coordinated throughout the authoring process and not just at some phase of it.

Retrieval hierarchies in hypertext

Abstract We have developed a collaborative, reuse hypertext system that has novel browsing and retrieval characteristics. The system, called Many Using and Creating Hypertext (MUCH), has been implemented on a network of UNIX workstations and used extensively in our group. This paper presents the model underlying the use of the MUCH system with respect to organizing, retrieving, and reorganizing information. In order to reuse information successfully, one must first organize it, then retrieve it, and finally reorganize it. The storage layer of hypermedia is logically based on nodes and links, and the MUCH system assumes that the names for these nodes and links represent a kind of semantic net. Documents, thesauri, and discussions may all be connected in this semantic net. The various functionalities of the system then exploit the knowledge in this semantic net. Traversals of the net with various filters are the basis for the views that users get of the semantic net. The standard perspective is of a fold-unfold outline that represents a fisheye view of the semantic net. The reorganization of information also depends on a selection of nodes and their presentation within a connected subnet.

An expertext system for collaborative authoring

Abstract This paper describes the principles behind and the design and implementation of a collaborative expertext authoring tool. The system presented aims to act as an intelligent assistant. It is based on a model of writing as a problem-solving activity, constrained by goal and audience, in which success depends on allowing the user to witch at will between the different phases of the task. Key to achieving this role is its ability to make explicit the implicit semantics of associative links in the hypertext. In order to guide the user, a knowledge base is provided by the system which an author can edit and which determines how the hypertext network is edited and traversed in the course of generating linear documents. In this way, minor modifications of the knowledge base can readily lead to significant reorganization of a document.

Software reuse: from text to hypertext

For software reuse, a wide range of software descriptions are exploited in the ESPRIT Practitioner Project. Word patterns and outlines constitute the conventional document-oriented descriptions, whereas thesauri and questionnaires form the hypertext-oriented descriptions. The Practitioner consortium has developed and tested a set of tools to support this wide range of approaches to software reuse. Furthermore, all the phases of reuse, i.e. organising, retrieving and reorganising, have been applied to documents from throughout the software life-cycle.

Domain Model Based Hypertext for Collaborative Authoring

Domain information models reflect the common structural and semantic characteristics of information organization in particular domains. This chapter describes the creation of a domain model based hypertext and the experiences gained in using such semantic net based systems. Experiences indicate that the use of semantic nets for representing domain model based hypertext can enhance hypertext organization and can maintain the structural and semantic consistency of the documents created in a collaborative environment. An active management document defined with such a model can facilitate the coordination of an authoring team. The structured hypertext feature of such a system can facilitate the automatic construction of HTML; hence the methods advocated in this paper for structuring and managing collaborative hypertext are directly applicable to the World Wide Web.

Collaborative Software Reuse Integrated into the Work Flow

Abstract Existing work patterns must be closely observed in developing a software reuse tool that is accepted. The results of the PRACTITIONER Project confirmed the significance of the understanding of an application domain and the human factors in the work flow. In this paper we present a model for collaborative software development in general and for software reuse in particular. This model takes an object-oriented approach and puts stress on the management side of the collaboration, such as the coordination embedded in the role allocation and automatic message passing. Experiments to validate the model are undergoing along with the redesigning of our hypermedia collaborative and reuse support system. Several examples are given to show how this model fits into the work flow.