88,886 research outputs found

    A Cultural-Historical Activity Theory Approach to Users, Usability and Usefulness

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    This paper takes an historical overview of the field of Human-Computer Interaction. It describes how the cognitive psychology emphasis on user involvement in systems development of the 1980s reached its limit by the early 1990s. At this point the focus shifted onto support for the tasks of users using computer-based systems in real contexts, a focus that ideally suits the mobile, ubiquitous and social technologies of the new millennium. The Cultural-Historical Activity Theory provides an appropriate framework for understanding this phenomenon and is adopted in this paper to present the work, over a seven year period, of a usability laboratory grounded in Activity Theory principles

    The evolution of anti-circumvention law

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    Countries around the world have since 1996 updated copyright laws to prohibit the circumvention of "Technological Protection Measures", technologies that restrict the use of copyright works with the aim of reducing infringement and enforcing contractual restrictions. This article traces the legislative and treaty history that lies behind these new legal provisions, and examines their interaction with a wide range of other areas of law: from international exhaustion of rights, through competition law, anti-discrimination measures, regulation of computer security research, constitutional rights to freedom of expression and privacy, and consumer protection measures. The article finds that anti-circumvention law as promoted by US trade policy has interfered with public policy objectives in all of these areas. It picks out key themes from the free trade agreements, legislation and jurisprudence of the World Trade Organization, World Intellectual Property Organization, USA, EU member states, and South American, Asian and Australasian nations. There is now a significant movement in treaty negotiations and in legislatures to reduce the scope of anti-circumvention provisions to ensure their compatibility with other important policy objectives

    Pervasive Technologies and Support for Independent Living

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    A broad range of pervasive technologies are used in many domains, including healthcare: however, there appears to be little work examining the role of such technologies in the home, or the different wants and needs of elderly users. Additionally, there exist ethical issues surrounding the use of highly personal healthcare-related data, and interface issues centred on the novelty of the technologies and the disabilities experienced by the users. This report examines these areas, before considering the ways in which they might come together to help support independent-living users with disabilities which may be age-related

    Vibration serviceability of footbridges under human-induced excitation : a literature review

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    Increasing strength of new structural materials and longer spans of new footbridges, accompanied with aesthetic requirements for greater slenderness, are resulting in more lively footbridge structures. In the past few years this issue attracted great public attention. The excessive lateral sway motion caused by crowd walking across the infamous Millennium Bridge in London is the prime example of the vibration serviceability problem of footbridges. In principle, consideration of footbridge vibration serviceability requires a characterisation of the vibration source, path and receiver. This paper is the most comprehensive review published to date of about 200 references which deal with these three key issues. The literature survey identified humans as the most important source of vibration for footbridges. However, modelling of the crowd-induced dynamic force is not clearly defined yet, despite some serious attempts to tackle this issue in the last few years. The vibration path is the mass, damping and stiffness of the footbridge. Of these, damping is the most uncertain but extremely important parameter as the resonant behaviour tends to govern vibration serviceability of footbridges. A typical receiver of footbridge vibrations is a pedestrian who is quite often the source of vibrations as well. Many scales for rating the human perception of vibrations have been found in the published literature. However, few are applicable to footbridges because a receiver is not stationary but is actually moving across the vibrating structure. During footbridge vibration, especially under crowd load, it seems that some form of human–structure interaction occurs. The problem of influence of walking people on footbridge vibration properties, such as the natural frequency and damping is not well understood, let alone quantified. Finally, there is not a single national or international design guidance which covers all aspects of the problem comprehensively and some form of their combination with other published information is prudent when designing major footbridge structures. The overdue update of the current codes to reflect the recent research achievements is a great challenge for the next 5–10 years

    From the invalidity of a General Classification Theory to a new organization of knowledge for the millennium to come

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    Proceedings der 10. Tagung der Deutschen Sektion der Internationalen Gesellschaft für Wissensorganisation. Wien, 3-5 Juli 2006The idea of organizing knowledge and the determinism in classifícation structures implicitly involve certain limits which are translated into a General Theory on the Classifícation of Knowledge, given that classifícation responds to specific parameters and structures more than to a theoretical concept. The classifícation of things is a refiection of their classifícation by man, and this is what determines classifícation structures. The classifícation and organization of knowledge are presented to us as an artificial construct or as a useful fiction elaborated by man. Positivist knowledge reached its peak in the 20* century when science classifications and implemented classifícation systems based on the latter were to be gestated and Consolidated. Pragmatism was to serve as the epistemological and theoretical basis for science and its classifícation. If the classifícation of the sciences has given rise to clastification systems, the organisation and representation of knowledge has to currendy give rise to the context of the globalisation of electronic information in the hypertextual organisational form of electronic information where, if in information the médium ivas the message, in organisation the médium is the structure. The virtual reality of electronic information delves even deeper into it; the process is completed as the subject attempts to look for information. This information market needs standards of an international nature for documents and data. This body of information organization will be characterized by its dynamic nature. If formal and material structures change our concept of knowledge and the way it is structured, then this organization will undergo dynamic change along with the material and formal structures of the real world. The semantic web is a qualitative leap which can be glimpsed on tiie new knowledge horizon; the latter would be shaped with the full integration of contents and data, the language itself would include data and its rules of reason or representation system. The new organisation of knowledge points to a totally nCw conception; post-modern epistemology has yet to be articulated. In the 21 st century, the organization of electronic information is presenting a novel hypertextual, non-linear architecture that will lead to a new change in the paradigm for organization of knowledge for the mülennium to come.Publicad

    Experimental evidence for mixed reality states

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    Recently researchers at the University of Illinois coupled a real pendulum to its virtual counterpart. They observed that the two pendulums suddenly start to move in synchrony if their lengths are sufficiently close. In this synchronized state, the boundary between the real system and the virtual system is blurred, that is, the pendulums are in a mixed reality state. An instantaneous, bidirectional coupling is a prerequisite for mixed reality states. In this article we explore the implications of mixed reality states in the context of controlling real-world systems.Comment: 2 pages, 2 figure
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