72,868 research outputs found

    Reconciling visions and realities of virtual working: findings from the UK chemicals industry

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    The emergence of advanced technologies such as Grid computing will, some suggest, allow the final realisation of visions of virtual organisations. This will, according to its advocates, have entirely positive impacts, creating communities of experts, increasing flexibility, reducing the need for travel and making communications more efficient by crossing boundaries of time and space. Such predictions about future patterns of virtual working are, unfortunately, rarely grounded in real working practices, and often neglect to account for both the rich and varied interpretations that may exist of what constitutes virtual working and the constraints and concerns of those who would do it. This chapter gives attention to the consequences of different views over what virtuality might mean in practice and, in particular, considers virtuality in relation to customer and supplier relationships in a competitive and commercial context. The discussion is based upon a three year study that investigated contrasting visions of what was technically feasible and might be organisationally desirable in the UK Chemicals industry. Through interviews with managers and staff of companies both large and small that research provided insights into the different meanings that organisations attribute to the virtuality of work and to the acceptability of potential implementations of a middleware technology. It was found that interpretations of virtuality amongst the potential users and participants were strongly influenced by established work practices and by previous experiences of relationships-at-a-distance with suppliers and customers. There was a sharp contrast with the enthusiastic visions of virtual working that were already being encapsulated in the middleware by the technical developers; visions of internet-only interaction were perceived as rigid, alienating from well-established ways of working with suppliers and customers and unworkable. In this chapter we shall capture these differences by making a distinction amongst compet

    Channel and active component abstractions for WSN programming - a language model with operating system support

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    To support the programming of Wireless Sensor Networks, a number of unconventional programming models have evolved, in particular the event-based model. These models are non-intuitive to programmers due to the introduction of unnecessary, non-intrinsic complexity. Component-based languages like Insense can eliminate much of this unnecessary complexity via the use of active components and synchronous channels. However, simply layering an Insense implementation over an existing event-based system, like TinyOS, while proving efficacy, is insufficiently space and time efficient for production use. The design and implementation of a new language-specific OS, InceOS, enables both space and time efficient programming of sensor networks using component-based languages like Insense

    A Rule-Based Consultant for Accelerator Beam Scheduling Used in the CERN PS Complex

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    The CERN PS accelerator complex consists of nine interacting accelerators which work together to produce particle beams for different end users, varying in particle type, energy, time structure, and geometry. The beam production schedule is time sliced and depends on the current operational requirements and dynamically on the accelerator status, so that production schedule changes occur in real time. Many potential schedules are not valid due to various system constraints and these constraints vary over time as new operational modes are introduced. In order to ensure that only valid schedules are given to the complex, an automated tool has been developed to indicate whether a potential schedule is valid or not. This presentation describes the method by which the validity of a beam schedule is determined and how this method was implemented using a rule-based approach based on SQL, avoiding the use of an expert system shell. Both the data to instantiate the rules and the rules themselves are kept in an Oracle data base. The SQL interpreter provides the inference engine for this knowledge-based system. A few examples are presented and the running experience with the tool is discussed

    Development and test of video systems for airborne surveillance of oil spills

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    Five video systems - potentially useful for airborne surveillance of oil spills - were developed, flight tested, and evaluated. The systems are: (1) conventional black and white TV, (2) conventional TV with false color, (3) differential TV, (4) prototype Lunar Surface TV, and (5) field sequential TV. Wavelength and polarization filtering were utilized in all systems. Greatly enhanced detection of oil spills, relative to that possible with the unaided eye, was achieved. The most practical video system is a conventional TV camera with silicon-diode-array image tube, filtered with a Corning 7-54 filter and a polarizer oriented with its principal axis in the horizontal direction. Best contrast between oil and water was achieved when winds and sea states were low. The minimum detectable oil film thickness was about 0.1 micrometer

    Towards a generalized theory of low-frequency sound source localization

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    Low-frequency sound source localization generates considerable amount of disagreement between audio/acoustics researchers, with some arguing that below a certain frequency humans cannot localize a source with others insisting that in certain cases localization is possible, even down to the lowest audible of frequencies. Nearly all previous work in this area depends on subjective evaluations to formulate theorems for low-frequency localization. This, of course, opens the argument of data reliability, a critical factor that may go some way to explain the reported ambiguities with regard to low-frequency localization. The resulting proposal stipulates that low-frequency source localization is highly dependent on room dimensions, source/listener location and absorptive properties. In some cases, a source can be accurately localized down to the lowest audible of frequencies, while in other situations it cannot. This is relevant as the standard procedure in live sound reinforcement, cinema sound and home-theater surround sound is to have a single mono channel for the low-frequency content, based on the assumption that human’s cannot determine direction in this band. This work takes the first steps towards showing that this may not be a universally valid simplification and that certain sound reproduction systems may actually benefit from directional low-frequency content
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