Catálogo de publicaciones - libros

In this article we consider the initial-boundary value problem for linear and nonlinear wave equations in an exterior domain Ω in with the homogeneous Dirichlet boundary condition. Under the effect of localized dissipation like () we derive both of local and total energy decay estimates for the linear wave equation and apply these to the existence problem of global solutions of semilinear and quasilinear wave equations. We make no geometric condition on the shape of the boundary Ω.

The dissipation () is intended to be as weak as possible, and if the obstacle = ∖ Ω is star-shaped our results based on local energy decay hold even if () ≡ 0, while for the results concerning the total energy decay we need () ≥ > 0 near ∞.

In the final section we consider the wave equation with a ‘half-linear’ dissipation () which is like ()|| in a bounded area and which is linear like () near ∞.

If future interaction design is to take designing for experience seriously we must first understand more clearly what we mean by experience. We argue that the science-based disciplines usually associated with human-computer interaction may not be the best place to look for such theoretical foundations and that it may be time for human-computer interaction to look farther afield to the arts and humanities. We have turned towards the pragmatic philosophy of John Dewey and the literary theory and philosophy of Mikhail Bakhtin as our starting point. In this chapter we lean on Bakhtin's analysis of the novel and “felt life” and use this to explore ways in which we can help designers engage with experience. Building on Bakhtin's analysis of creative understanding, we argue for a dialogical analysis of the relationship between designer and user. We conclude with one or two interesting examples of design work that seem to capture the spirit of this approach to design.

This chapter outlines a “human-centred” perspective on the design of novel interactive artefacts and environments. The approach builds on a variety of human and social science traditions that focus on understanding human activity, all of which seek to provide useful and pertinent observations on human action in the world. While technology may play an important role in these human activities, often the use of the technology is as an intrinsic mediating influence, rather than being the goal of the activity. The relevance of this approach to technology development is that it provides a distinct perspective that encompasses many of the key issues being faced by (ubiquitous) technology designers today — issues such as awareness, context, interaction, engagement and emotion. All of these aspects concern the activities of human actors in a (variety of) setting(s). The chapter then outlines a major research programme being conducted within our research unit which provides an exemplar of the human-centred interaction design research programme that we are advocating, which we believe could significantly shift the way in which we design, develop and evaluate novel technological artefacts and environments.

Identity construction in computer-mediated environments as in “real life” environments, is influenced by existent social processes. In these virtual environments the computer screen mediates specific experiences of localised physicality; however these computer mediated experiences do not alter the overall sense of being for the individual. To interact with the Web Information System in virtual space the individuals do not leave the essence of themselves on one side of the screen to acquire a new layer of meanings and self-ascription within the virtual space. Identity construction is similarly a complex process in cyberspace as it is in real life. In this chapter we will present a post-structural discussion arguing that electronic identity enables a deconstruction of the mind/body dichotomy. We argue that when individuals interact with a Web information system, in virtual space, they do not leave the essence of themselves on one side of the screen to acquire a new layer of meaning and self-ascription within the virtual space that the system occupies. Further, issues of design are considered in regard to systems development that aim at supporting computer-mediated identity construction.

Explanatory design means the practice by which design solutions are evidence-based. This practice has been the norm in engineering design, relying as it does on the laws of science, but much less attention has been paid to the necessity of abandoning intuitive practices in designing for the human element within technological systems. One reason for this may have been the variety of explanatory bases within psychology. There is no single psychological framework for explaining human behaviour; instead different types of problems must be solved by using very different types of explanatory frameworks and theory language. Cognitive capacity, emotions and mental contents may serve as examples of very different explanatory frameworks. Developing a theory of explanatory interaction design needs to be based on an improved understanding of the differences between explanatory frameworks.

Traditionally, cognitive analysis of interaction has been done by applying theoretical models of human cognitive processes proposed by cognitive psychologists. However, this approach is now facing an important problem: predictions made from these models developed in laboratory settings with particular materials, tasks and people are not confirmed when we have to predict how a person interacts with a device. This failure could be explained by recognising that these theoretical models incorrectly assume that the human cognitive processes work independently of context. Furthermore, traditional analysis of interaction has also incorrectly assumed that the human being is the only cognitive agent in the interaction. We propose to replace this analysis by another one in which interaction design should be based on the idea that human cognitive processes adapt their operations to contextual changes to interact with other cognitive agents, devices, to perform jointly the task at hand. In this chapter we define some steps towards the development of this new cognitive analysis. In addition, we present the principle of “mutual dependency” that could be of much use in facing the future of interaction design.

Metaphors are a key part of human conceptualisation processes. Conceptualising contemporary information and communication technology is no exception. The way we communicate with and with the help of modern technology can be understood and conceptualised as a matter of metaphor. Within the context of interaction design, however, the term metaphor has been used in a way that is not coherent with its use in metaphor theories, which arise from linguistics. The conceptual vagueness in the context of interaction design has resulted in mistrust toward metaphor as a design principle. In this chapter metaphor is redefined for the needs of design. It is argued that the questioning of the power of metaphor in design is a consequence of using the concept in a loose manner. Contemporary metaphor theories provide an extremely interesting perspective to design. In this chapter, a sample design is analysed in terms of the proposed theoretical framework.

The forecast advent of ubiquitous computing promises to bring about a radical shift in our way of interacting with computing systems. It is expected that people will interact continuously with computation, in an ever-increasing range of forms, situations and locations. Current user-centred design methodology is severely stretched when applied to this new context. This chapter discusses the nature of ubiquitous computer-human interaction and proposes a set of five design principles that can inform some of the choices interaction designers need to make when shaping the human experience of a ubiquitous computing environment. We discuss these principles in the context of designing for the connected family: how to support communication within families and across generations. We describe some lessons from our research in designing for enhanced social communication between family members and some of the research challenges ahead.

The western world is experiencing a rapid increase in the use of computers and other interactive electronic products by people of all ages and all walks of life. Computer interaction is no longer restricted to the workplace and for use by those “at work” and is now found everywhere including over the phone and in many useful electronic products.

The envelope of the user group for computer interaction is stretching to incorporate a wide range of people and abilities. Designers can no longer rely on their target user coping with the intricacies of multitasking, multifunction systems of the workplace machine, and must look to the needs of the wider population.

The focus of this contribution is special design which will enable a particularly large group of new users, older adults, to participate fully in the use of information technology, and which will also help them to stay happy, healthy and independent for longer.

We are facing an inevitable invasion of digital computation in our surroundings and in everyday objects such as toys, teapots and t-shirts. At this point in time we have no way of knowing what this invasion will mean to us and to our daily lives. We know that it will happen, however, and we know that we will have to deal with this exponential growth in computational complexity — both in our daily lives and in all the various disciplines involved in the development of our everyday surroundings. Once imbued with the capacity to communicate and to compute, our teapots may never be the same again. Certainly the task of designing such everyday artefacts will be a very different and much more complex task than design schools ever envisioned.

This chapter provides an overview of some of the design challenges associated with this development. Through the introduction of a simple functional taxonomy it is shown that the ever-increasing complexity of artefacts requires an expansion of the notion of design to cover disciplines ranging from political science to software engineering. Furthermore, only a concerted effort among these disciplines can aspire to create a worthwhile and sound world of communicating computational artefacts.

The chapter claims that the complexity must be dealt with in a controlled bottom-up fashion. The ideals and ideas of self-organising systems built on basic rules and guidelines must be applied to computational artefacts in order for them to be able to cope with their peers and serve their creators. But the choice of rules and regulations is crucial on many levels including the social and political. These choices determine the range of behaviours and the types of social constructs exhibited by communities of people and computational artefacts. The bottom-up development must therefore be strongly coupled with a vision of the kind of society we wish to create and what role computational artefacts will play in that society.

This means that design is both a question of responsible social intervention and of facilitating the unexpected. This chapter thus argues for a very broad concept of interaction design as well as for the creation of structures and environments in which this broad design discussion and practice can take place.