To help us identify and focus on pragmatic and concrete issues related to the role of software architecture in the design and development of large systems, we conducted a survey of a variety of software systems used in industrial applications. Our premise, which guided the examination of these systems, was that software architecture is concerned with capturing the structures of a system and the relationships among the elements both within and between structures. The structures we found fell into several broad categories: conceptual structure, module structure, code structure, and execution structure. These categories address different engineering concerns. The separation of such concerns, combined with specialized implementation techniques, decreased the complexity of implementation, and improved reuse and reconfiguration. We observed that in practice, software architecture played an important role throughout the development process: specification, design, functional decompo...

Reflecting the growing consensus that principles and methods for developing effective interfaces are beginning to mature, usability design guidelines have begun to proliferate. But current approaches to guidelines tend to either be technology-centric, focusing on platform-specific interface widgets, or abstract and general-purpose. At best, these general guidelines provide weak support that is insufficient to support developers faced with specific interface design problems targeted for specific user populations. If the potential of usability guidelines as an interface design technique is to be fully realized, they need to be augmented with context-specific guidelines and examples that synthesize isolated guidelines into domain-specific solutions to design problems. In this paper, we present a method in which software development organizations can develop and evolve domain-specific guidelines based on the kinds of applications they develop. The method facilitates the process of determin...

The importance of an early and on-going focus on users in interactive system design is widely accepted. However, in practice, involving users poses many problems and requires designers to balance conflicting demands. Various factors can hinder or ease the involvement of users. This paper reports a case study involving the design of a bespoke application and gives a detailed account of the obstacles and facilitators to user involvement encountered during the design activity. The obstacles and facilitators are presented in terms of issues such as contacting and selecting users, motivating users, facilitating and mediating meetings and offering points of focus for user contributions. We report and contrast the views of various stakeholders in the design process, and supplement these with our own observations as non-participant observers. Finally, we discuss issues raised by the study and draw out a number of lessons for the CHI community.

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.

Software design methods share many characteristics with design methods in other fields. All these methods are the progeny of philosophies of design that are in turn influenced by more general philosophic movements. This essay begins with the influence of philosophies of science on the study of design, highlighting the effects on design discourse of Cartesian rationality, the hypothetico-deductive account of scientific progress, and Kuhnian paradigms. Next, the influence of the constructivist and humanist movements on design thinking are considered, culminating in the introduction of a philosophy of design based on hermeneutics, or interpretation. The influence of design philosophy on software design methods begins a categorization of several software design methods according to the design theory framework, with some emphasis on design methods that support a hermeneutical style of design. Some justification for a pluralistic approach to software design methodology rounds out the essay. ...

The cognitive activities performed by systems designers during systems development include problem understanding, problem decomposition and solution speci"cation. One aspect of object-oriented (OO) approaches to system design that appeals to many adopting organizations is the purported naturalness, i.e. the consistency of OO approaches with these cognitive activities of problem solving. Essentially, OO aims to abstract components of the problem of system development to a high level that parallels problem solving in the world the system represents. In other words, knowing how a problem is solved in the real world informs one about how the OO system solves the problem. Thus, the OO development process and the resulting OO model are believed to be consistent with innate cognitive activities and consistent with the problem/real world, respectively. A cognitive mapping method was used to ask graduate students experienced with OO techniques about their perceptions of what is complex (di$cult to understand) about OO systems. Their responses include a set of concepts, categories of similar concepts and cognitive maps that reveal what they believe is di$cult about using OO techniques. Evaluating these perceptions in terms of the cognitive activities of system design reveals problem decomposition was perceived as the activity that caused the most di$culties related to learning OO techniques. Problem understanding was the goal of the participants, while the solution activity ranked lower in importance but contained many issues essential to systems development and in#uenced problem understanding.

A. PROJECT SUMMARY Interactive computing systems are only as good as the tasks that they support. Designers of interactive systems have recognized this and begun to incorporate use-oriented design representations into their system development activities. One such representation is a task scenario, a narrative describing one or more users interacting with a computer to accomplish some task. But despite the increasing importance of scenarios to design practice—they can be used to express requirements, to envision new designs, to communicate design ideas to users, to evaluate prototype systems, to test theoretical models—there is no systematic, integrative methodology or framework to guide this practice. Scenario generation and application remains an art. This research seeks to develop such a framework. It uses converging methods to systematize the concept of task scenario, to articulate the properties that make a scenario good for one design activity vs. another, and to develop tools and techniques that will guide designers in effective and efficient application of these use-oriented design representations. Studies of scenarios created in representative design projects, combined

Introduction The aim of our research is to provide input for the development of design support (e.g., design methods or tools) for user interface design. Before new methods or tools can be developed, we have to determine what design support is being used presently, and what new or improved design support designers require. Many design methods and tools have already been developed. Some are used for a specific design activity such as task analysis, prototyping or evaluation of the design, whereas others cover the complete design process. Previous research has shown that design support (design methods and tools) is not used as often as expected (Bellotti, 1990;, Gould et al., 1991). It is apparent that the design methods and tools are difficult to apply under constraints of practice, e.g., considerable time is required to get familiar with new methods. We applied the well-known design principle "know thy user" to the development of design methods and tools. Therefore, we decided

This paper concerns the development of complex systems from the point of view of design as a structure of activities, related both to the clients and the users. Several modeling approaches will be adopted for different aspects of design, and several views on design will be integrated. The proposed activity structure is based on teaching design practice, and will be illustrated by examples from design courses for university students and for practitioners in industry.

The Swedish MultiG program addresses research issues in distributed multimedia workstation applications, including CSCW, and high-speed networks. This report treats some basic CSCW issues in a distributed design environment. We review and analyse relevant literature on system design and computer supported cooperation and discusses the basic issues: What is design?What is collaboration in design? What computer support is necessary for collaboration in a distributed design environment? A task analysis is performed of design and collaboration. Computer support for these tasks in a distributed environment is discussed with emphasis on generic tools for informal collaboration.