Hypertext engineering environments can be modeled to a certain degree on software engineering development environments. For example, designing the conceptual hypertext data model and abstract navigational model [22] can benefit directly from software engineering approaches. Fundamental differences, however, make a pure transposition of techniques both difficult and inadequate. An important part of hypertext design concerns aesthetic and cognitive aspects that software engineering environments do not support.This article focuses on the hypertext 1 design task itself as a computer-supported activity. In it we provide guidelines for developers of hypermedia design environments to facilitate the user's design process. A hypertext design environment can support both formal hypermedia design techniques and the actual design process successfully. While we take advantage of object-oriented terminology to describe certain concepts, the lessons of this article apply to all formal design techniques. Thus we neither proscribe nor detail a formal design model. Instead we examine the general human-factor aspects of the design process to determine which features help designers most. We also enumerate the requirements hypermedia design environments have that other types of computer applications do not. This analysis arises from observing users and students during design tasks, and is grounded in sound and well-known results in cognitive science. It builds upon our experience in developing LIRMM's MacWeb 2 hypermedia development environment [14][15][16]. Dimensions of the Hypertext Design ActivityOne may consider hypermedia design, as with any other COMMUNICATIONS OF THE ACM August 1995/Vol. 38, No. 8 49J o c e l y n e N a n a r d a n d M a r c N a n a r d Hypertext DesignEnvironments and the Hypertext Design Process mproving the quality of hypermedia design and reducing its cost is an important challenge for the information industry. One way to tackle the problem is to provide hypertext designers with appropriate development environments. Hypertext engineering environments that provide sets of integrated tools boost designers' efficiency and effectiveness. 1 Hypertext and hypermedia are handled similarly in design. Both refer to organized sets of information linked by semantic relationships, and therefore are indistinguishable in this article.2 MacWeb [14,15] is a knowledge-based hypertext system developed at LIRMM since 1989. To avoid any confusion, note that it is unrelated to the World-Wide Web client developed later with the same name. We used the name MacWeb first (and have published articles referring to it that predate the WWW client). design activity, from two points of view or dimensions:• prescribed formal design techniques to produce the design • observations on how people actually conduct the design processMost material concerning hypermedia design focuses mainly on the first dimension, proposing a formal technique for a certain class of application domains (for example, see [8] Designers, on the other hand, as huma...

It has been shown that the famous problem of user disorientation in hypertext is not due to the concept of hypertext itself but rather generally results from the lack of a conceptual model for hypertext application. Unfortunately, in most hypertext systems, the weakness of structure specification mechanisms discourages the development and use of such a model since it is difficult to reinforce hypertext structure and to really incorporate knowledge. A lot of works provide intelligent mechanisms to help navigation but either they use external knowledge or automatically synthesize links from information included in nodes which thereby have no sufficient conceptual value.The present paper focuses on an object-oriented hypertext model (implemented in the MacWeb system) using structured types to incorporate knowledge in hypertext.Concepts and their relationships as well as their instances and their own relationships may be represented. Such a model makes the capture of knowledge at source easier thus allowing a more conceptual navigation, Furthermore, active behaviors may be associated, as methods, to types. This provides a powerful mechanism to help develop structured hypertext as well as task centered applications, by taking advantage of knowledge representation.

Abstract. Traditionally, the use of good techniques to improve software modularity, such as advanced separation of concerns, has no impact in the user experience, for example while navigating Web software. While the intent of these techniques is to simplify evolution and maintenance, navigation design quality is often seen as an unrelated concern. In this paper we present a novel approach for improving navigation in Web applications by using some of the core application's concerns (called navigational concerns) to derive their navigational structure. Using some realistic examples we show that, by carefully using these concerns, we can improve the user experience. Some implementation issues are discussed and a thorough comparison with related ideas in the Web Engineering field is presented.

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