AbstractÐThis paper examines and proposes an approach to writing software specifications, based on research in systems theory, cognitive psychology, and human-machine interaction. The goal is to provide specifications that support human problem solving and the tasks that humans must perform in software development and evolution. A type of specification, called intent specifications, is constructed upon this underlying foundation. Index TermsÐRequirements, requirements specification, safety-critical software, software evolution, human-centered specifications, means-ends hierarchy, cognitive engineering.

This article shows how the concept of affordance in the user interface fits into a wellunderstood artificial intelligence (AI) model of acting in an environment. In this model AI planning research is used to interpret affordances in terms of the costs associated with the generation and execution of operators in a plan. We motivate our approach with a brief survey of the affordance literature and its connections to the planning literature, and then explore its implications through examples of common user interface mechanisms described in affordance terms. Despite its simplicity, our modeling approach ties together several different threads of practical and theoretical work on affordance into a single conceptual framework. Affordances in a planning representation 3 Contents 1 INTRODUCTION 4 2 PERSPECTIVES ON THE NATURE OF AFFORDANCES 5 3 AFFORDANCES IN PLANNING TERMS 8 4 GENERIC USER INTERFACE AFFORDANCES 13 4.1 Programmable User Models for Affordance Evaluation . . . . . . . . . . ....

This study lies in the context of virtual engineering and human information systems. We propose to model and implement the behaviour of believable virtual agents, using ideas from psychology (cognitive maps, a#ordances) and neurophysiology (active perception, movement prediction) . Virtual worlds are peopled with autonomous entities improvising in free interaction. Autonomization of a model consists in giving to it a sensorimotor interface and also a decision module so that it could adapt its reactions to inner and extern stimuli. We propose in this article the basis for a behavioral model imitating human beings' perceptive operation. The psychological notion of "a#ordance " will help us in the construction of fuzzy cognitive maps for believable virtual human behaviour specification. Sensus Alain Berthoz, neurophysiologist, perception is not only an interpretation of sensorial messages: it is also an internal simulation of the action and an anticipation of the consequences of this simulated action. Following neurophysiological experiments on hippocampus in which were observed oscillations permitting prediction of trajectories, our virtual actor uses fuzzy cognitive maps in an imaginary space and simulate a behaviour. This simulation in the simulation allows him to predict the consequences of actions. The expected benefit from our a#ordance-based and proactive model consists in elaborating a believable virtual helmsman within the framework of a virtual sailing ship. We have implemented such a virtual actor in the multi-agent environment oRis.

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Most requirements engineering (RE) research and practice embodies a philosophy that we will call abstractionism, which involves the building of simplified models of domains of discourse and proposed systems. Abstractionists make much use of formal models, such as goal dependency networks. An alternative design philosophy is contextualism, according to which the peculiarities of the context of use of a system must be understood in detail before the requirements can be derived. Contextualists use qualitative methods to uncover and help interpret these particularities. In this paper, we analyze what it would mean to combine the best features of abstractionism and contextualism, and we ground our discussion in an illustration of abstractionist and contextualist thinking about RE through goal refinement (GR). In the context of the domain of meeting scheduling, we contrast a wholly abstractionist approach to GR with one that incorporates data gathered using two ethnographic methods. In doing so, we consider each step of the abstractionist approach, illustrating where ethnographic data obtained in our work environment affects the model produced. As we proceed, we summarize the general lessons learned. We then discuss how other abstractionist and contextualist methods could be integrated.

In this article, we introduce some basic concepts from an emerging field called cognitive engineering that is designed to address these types of questions.

This paper discusses the possible adverse effects predictive aid usage may have on a controller’s mental model in a Free Flight environment. Free Flight is a concept that is aimed at increasing throughput in the National Airspace System. However, various studies have suggested that implementing free flight could result in a controller’s situation model being adversely affected given the lack of predictability in this environment. Consequently, the usage of predictive aids has been suggested as a possible solution to this problem. However, there is a possibility that the usage of such aids may negatively affect a controller’s underlying mental model and thus, reduce his/her the ability to predict system behavior through mental simulations. Drawing on the results from two studies, we argue that caution must be exercised when introducing predictive aids under Free Flight conditions, given the possibility that such usage may adversely affect the controller’s underlying mental model, which can ultimately result in performance being compromised.

AVIATION (RBN) 32 p

to provide computer functionality to everyday objects. This idea is exemplified by Ubiquitous Computing (UbiComp) [10] and Augmented Reality [1]. Proponents argue that systems should be embedded in the environment. The technology should be distributed (ubiquitous), yet invisible, or transparent, since the full potential of the computer can only be realized when the machine itself is hidden from the user. This concept marks a dramatic shift from the status quo in which interaction with the computer interferes with our activities rather than enhancing them. While the promise of technology based on UbiComp is truly exciting, we believe that this approach will succeed only if the design of these systems takes into account the human factors governing their use. The factors that we consider necessary for usable technology include invisibility as described above, the affordance of a seamless manual override, and provision of feedback to the user. (See the accompanying side panel for an illu

People deal with places in their everyday lives. Interactions with places are based on the meaning people assign to them. In order to integrate the concept of place into geographic information systems (GIS), places have to be modeled. This paper presents a methodology to model places with affordances. Affordances are what objects or things offer people to do with them. Our methodology of modeling places with affordances integrates cognitive and engineering aspects, therefore leading to a knowledge-representation that comes closer to the user. An example is used to show the applicability of the model. Our conclusion is that the integration of affordance-based models of places into future GIS will lead to a better communication between users and systems.