Requirements traceability is intended to ensure continued alignment between stakeholder requirements and system evolution. To be useful, traces must be organized according to some modeling framework. Indeed, several such frameworks have been proposed, mostly based on theoretical considerations or analysis of other literature. This paper, in contrast, follows an empirical approach. Focus groups and interviews conducted in 26 major software development organizations demonstrate a wide range of traceability practices with distinct low-end and high-end users of traceability. From these observations, reference models comprising the most important kinds of traceability links for various development tasks have been synthesized. The resulting models have been validated in case studies and are incorporated in a number of commercial traceability tools. The discussion of the link types and their usage in practice has implications for the design of next-generation traceability methods and tools.

Complex design problems require more knowledge than any single person possesses because the knowledge relevant to a problem is usually distributed among stakeholders. Bringing different and often controversial points of view together to create a shared understanding among these stakeholders can lead to new insights, new ideas, and new artifacts. New media that allow owners of problems to contribute to framing and resolving complex design problems can extend the power of the individual human mind. Based on our past work and study of other approaches, systems, and collaborative and participatory processes, this article identifies challenges we see as the limiting factors for future collaborative human-computer systems. The Envisionment and Discovery Collaboratory (EDC) is introduced as an integrated physical and computational environment addressing some of these challenges. The vision behind the EDC shifts future development away from the computer as the focal point, toward an emphasis that tries to improve our understanding of the human, social, and cultural system that creates the context for use. This work is based on new conceptual principles that include creating shared understanding among various stakeholders, contextualizing information to the task at hand, and creating objects to think with in collaborative design activities.

Human understanding in design evolves through a process of critiquing existing knowledge and consequently expanding the store of design knowledge. Critiquing is a dialog in which the interjection of a reasoned opinion about a product or action triggers further reflection on or changes to the artifact being designed. Our work has focused on applying this successful human critiquing paradigm to humancomputer interaction. We argue that computer-based critiquing systems are most effective when they are embedded in domain-oriented design environments, which are knowledge-based computer systems that support designers in specifying a problem and constructing a solution. Embedded critics play a number of important roles in such design environments: (1) they increase the designer's understanding of design situations by pointing out problematic situations early in the design process, (2) they support the integration of problem framing and problem solving by providing a linkage between the design...

We live in a world characterized by evolution -- that is, by ongoing processes of development, formation, and growth in both natural and human-created systems. Biology tells us that complex, natural systems are not created all at once but must instead evolve over time. We are becoming increasingly aware that evolutionary processes are ubiquitous and critical for technological innovations as well. This is particularly true for complex software systems because these systems do not necessarily exist in a technological context alone but instead are embedded within dynamic human organizations. The Center for LifeLong Learning and Design (L 3 D) at the University of Colorado has been involved in research on software design and other design domains for more than a decade. We understand software design as an evolutionary process in which system requirements and functionality are determined through an iterative process of collaboration among multiple stakeholders, rather than being completel...

This work analyzes the central role of interpretation in non-routine design. Based on this analysis, a theory of computer support for interpretation in cooperative design is constructed. The theory is grounded in studies of design and interpretation. It is illustrated by mechanisms provided by a software substrate for computer-based design environments, applied to a sample task of lunar habitat design. Computer support of

Self-directed learning is a continuous engagement in acquiring, applying and creating knowledge and skills in the context of an individual learner’s unique problems. Effectively supporting self-directed learning is one of the critical challenges in supporting lifelong learning. Self-directed learning creates new challenging requirements for learning technologies. Domainoriented design environments address these challenges by allowing learners to engage in their own problems, by providing contextualized support, and by exploiting breakdowns as opportunities for learning. Economies of educational knowledge constitute an emerging concept in which communities contribute toward the creation of information repositories, which can be reused and evolved by all members of the community for the creation of new environments. We argue and demonstrate that domain-oriented design environments can serve as models for these economies, that a software reuse perspective provides us with insights into the challenges these developments face, and that the creation and evolution of these economies are best understood as problems in self-directed learning. Keywords: Self-directed learning; lifelong learning; domain-oriented design environments; economy of educational knowledge; reuse; seeding, evolutionary growth, reseeding Demonstrations: A demonstration of the WebNet system described in this article can be found at

The power of the unaided, individual mind is highly overrated: The Renaissance scholar no longer exists. Although creative individuals are often thought of as working in isolation, the role of interaction and collaboration with other individuals is critical to creativity. Creative activity grows out of the relationship between individuals and their work, and from the interactions between an individual and other human beings. Because complex problems require more knowledge than any single person possesses, it is necessary that all involved stakeholders participate, communicate, collaborate, and learn from each other. Distances (across spatial, temporal, and technological dimensions) and diversity (bringing stakeholders together from different cultures) are important sources for social creativity. This paper describes conceptual frameworks and sociotechnical environments (derived from the systems that we have developed over the last decade) in which social creativity can come alive. Keywords design, social creativity, spatial distance, temporal distance, technological distance, diversity, communities of practice, communities of interest, division of labor

Design is a ubiquitous activity. The complexity of design problems requires communities rather than individuals to address, frame, and solve them. These design communities have to cope with the following barriers: (1) spatial (across distance), (2) temporal (across time), (3) conceptual (across different communities of practice, and (4) technological (between persons and artifacts). Over the last decade, we have addressed these barriers and have tried to create sociotechnical environments to turn them into opportunities for enhancing the social creativity of design communities. Categories and Subject Descriptors H.5.3 [Information Interfaces and Presentation]: Group and Organization Interfaces – computer supported cooperative

Design critiquing systems are a type of intelligent user interface used to support human designers in decision making. This paper places design critics in the larger context of intelligent user interface approaches and surveys several critiquing systems. Each approach and system is evaluated with respect to a five-phase design improvement process. This paper concludes with a summary of the state of the art in critiquing systems and recommendations for future research directions. 1.

Explanation is an important issue in building computer-based interactive design environments in which a human designer and a knowledge system may cooperatively solve a design problem. We consider the two related problems of explaining the system's reasoning and the design generated by the system. In particular, we analyze the content of explanations of design reasoning and design solutions in the domain of physical devices. We describe two complementary languages: task-method-knowledge models for explaining design reasoning, and structure-behavior-function models for explaining device designs. INTERACTIVE KRITIK is a computer program that uses these representations to visually illustrate the system's reasoning and the result of a design episode. The explanation of design reasoning in INTERACTIVE KRITIK is in the context of the evolving design solution, and, similarly, the explanation of the design solution is in the context of the design reasoning.