40 research outputs found

    Parietal lobe contribution to spatial processing: evidence from brain tumour patients

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    The main aim of this research project was to compare the effects of a parietal lesion in brain tumour patients with effects of prefrontal and premotor lesions on a number of processes related to the ability to operate in near space. More specifically, we studied the effects of a brain tumour lesion on two basic processes such as the ability to (i) reach an object in space and (ii) to integrate spatiotemporal information in a prediction task. Then, two more cognitive processes were investigated, namely (iii) the ability to perform visuospatial transformations and (iv) to encode and retrieve the spatial relation between letters in a string. To that purpose, an anatomical group study approach was used. The method allowed us to better localize the relevant systems involved on the processes investigated..

    Timing Predictability in Future Multi-Core Avionics Systems

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    A knowledge based structure for implementing Value Management in the design of office buildings

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    Value Management (VM) is an organised effort directed at analyzing the functionsof systems, supplies, equipments and facilities, for the purpose of achieving therequired functions at lowest overall cost, consistent with requirements for performance,including reliability, delivery, maintainability and human factors. Thisstructured method can also be successfully used to define the scope of a project. Inthe UK, the awareness of the tremendous potential and benefits of applying VM toconstruction projects has made some clients eager to apply this technique to theirprojects. There are, however, a number of problems which inhibit the use of thisadvanced technique in the construction industry. Qualified VM specialists, forinstance, are very scarce within the industry, it is often difficult to find them toundertake proper VM studies. This research therefore aimed at exploring thefeasibility of building a Knowledge-Based System (KBS) to facilitate VM implementationsin the design stages of a construction project. A demonstration system has beensuccessfully developed to illustrate the facilities which would be available to potentialusers in a fully developed system. A method of allocating project cost againstfunctions of the project specified by the clients has been developed, which couldexpedite the processes of clarifying clients' brief and ensuring good value for moneyby cutting unnecessary costs and enhancing required functions. The research has alsoexplored how KBSs can be effectively applied to "open-ended" decision-makingproblems in which new options may be generated during each session with thesystem, i.e. the study considered the possibility of letting users extend and customisethe knowledge base. The system has been described as a "satisfactory and verypromising system" by the UK industrial specialists

    Third International Symposium on Space Mission Operations and Ground Data Systems, part 2

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    Under the theme of 'Opportunities in Ground Data Systems for High Efficiency Operations of Space Missions,' the SpaceOps '94 symposium included presentations of more than 150 technical papers spanning five topic areas: Mission Management, Operations, Data Management, System Development, and Systems Engineering. The symposium papers focus on improvements in the efficiency, effectiveness, and quality of data acquisition, ground systems, and mission operations. New technology, methods, and human systems are discussed. Accomplishments are also reported in the application of information systems to improve data retrieval, reporting, and archiving; the management of human factors; the use of telescience and teleoperations; and the design and implementation of logistics support for mission operations. This volume covers expert systems, systems development tools and approaches, and systems engineering issues

    A systems architecture-based approach to assess candidate upgrades to complex systems

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Engineering Systems Division, 2012."September 2012." Cataloged from PDF version of thesis.Includes bibliographical references (p. 163-167).The Compatibility Assessment Method (CAM), a new structured process for assessing compatibility between parent systems and child subsystems is proposed and applied to several cases where subsystems are being replaced in legacy systems. CAM is a screening process intended to be used by project managers who need to replace components of complex systems. The functional model-based process uses an extension of the Integrated Definition Modeling Language of IDEFO. The IDEFO method is used for defining compatibility measures based on each of the four constituent arrows that show inputs, controls, outputs, and mechanisms (ICOM). In this extension, the control constituents are replaced with constraints. Each of the ICOM constituents is expanded with parameters which include metrics and values. The ICOMs with their parameters and metrics are then used to characterize two or more subsystems in a matrix format. The differences between these matrices are entered into the sparse "Delta Matrix" which shows analysts the differences between the systems. These differences can be assigned to the appropriate levels of technical expertise to be analyzed and to determine feasibility of the child subsystem in the parent system. The process is compared to current practices in government unmanned aircraft system program offices to determine the usefulness of adopting this compatibility assessment process. This dissertation outlines the need for and development of the method for application by practitioners responsible for replacing subsystems on legacy systems. The development includes evaluations of the method and an experiment with cohorts of student system engineers to compare the output of the Compatibility Assessment Method to less-structured methods. This research contributes additional insight into system architecting theory and proposes a structured method for practitioners to use to improve the processes to perform part replacement in legacy systems. While others have offered methods to measure aspects of system architecture, this proposed method moves beyond the extant literature with tools for practitioners.by David Scott Andrew Long.Ph.D

    Software Productivity

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    A software maintenance method based on the software configuration management discipline

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    Software maintenance has until recently been the neglected phase in the software engineering process, despite the fact that maintenance of existing software systems may account for over half of all efforts expended by a software organization. Research into software maintenance, compared to other phases of the software engineering process is rare. Moreover, it is widely accepted that current software maintenance methods and techniques are unable to cope with the complexity inherent in maintaining software systems. This thesis is concerned with the development of a method, named Configuration Management Formalization for Maintenance (COMFORM), designed for the maintenance of existing software systems. COMFORM provides guidelines and procedures for carrying out a variety of activities performed during software maintenance. It accommodates a change control framework, around which the Software Configuration Management discipline is applied. Redocumentation is another problem tackled by COMFORM, which gathers together the documentation necessary to improve the maintainability and quality of existing software systems. This is achieved by the use of forms representing the output of each phase of a proposed software maintenance model. The information obtained by filling in forms is formalized according to a data model, which provides a common basis for the representation of the method's functionality. Finally, a prototype of COMFORM has been implemented, so that the procedures and guidelines set up by the method can be enforced and followed by its users

    Third International Symposium on Space Mission Operations and Ground Data Systems, part 1

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    Under the theme of 'Opportunities in Ground Data Systems for High Efficiency Operations of Space Missions,' the SpaceOps '94 symposium included presentations of more than 150 technical papers spanning five topic areas: Mission Management, Operations, Data Management, System Development, and Systems Engineering. The papers focus on improvements in the efficiency, effectiveness, productivity, and quality of data acquisition, ground systems, and mission operations. New technology, techniques, methods, and human systems are discussed. Accomplishments are also reported in the application of information systems to improve data retrieval, reporting, and archiving; the management of human factors; the use of telescience and teleoperations; and the design and implementation of logistics support for mission operations

    Space Station Systems: a Bibliography with Indexes (Supplement 8)

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    This bibliography lists 950 reports, articles, and other documents introduced into the NASA scientific and technical information system between July 1, 1989 and December 31, 1989. Its purpose is to provide helpful information to researchers, designers and managers engaged in Space Station technology development and mission design. Coverage includes documents that define major systems and subsystems related to structures and dynamic control, electronics and power supplies, propulsion, and payload integration. In addition, orbital construction methods, servicing and support requirements, procedures and operations, and missions for the current and future Space Station are included
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