1,900 research outputs found

    Optimal dynamic operations scheduling for small-scale satellites

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    A satellite's operations schedule is crafted based on each subsystem/payload operational needs, while taking into account the available resources on-board. A number of operating modes are carefully designed, each one with a different operations plan that can serve emergency cases, reduced functionality cases, the nominal case, the end of mission case and so on. During the mission span, should any operations planning amendments arise, a new schedule needs to be manually developed and uplinked to the satellite during a communications' window. The current operations planning techniques over a reduced number of solutions while approaching operations scheduling in a rigid manner. Given the complexity of a satellite as a system as well as the numerous restrictions and uncertainties imposed by both environmental and technical parameters, optimising the operations scheduling in an automated fashion can over a flexible approach while enhancing the mission robustness. In this paper we present Opt-OS (Optimised Operations Scheduler), a tool loosely based on the Ant Colony System algorithm, which can solve the Dynamic Operations Scheduling Problem (DOSP). The DOSP is treated as a single-objective multiple constraint discrete optimisation problem, where the objective is to maximise the useful operation time per subsystem on-board while respecting a set of constraints such as the feasible operation timeslot per payload or maintaining the power consumption below a specific threshold. Given basic mission inputs such as the Keplerian elements of the satellite's orbit, its launch date as well as the individual subsystems' power consumption and useful operation periods, Opt-OS outputs the optimal ON/OFF state per subsystem per orbital time step, keeping each subsystem's useful operation time to a maximum while ensuring that constraints such as the power availability threshold are never violated. Opt-OS can provide the flexibility needed for designing an optimal operations schedule on the spot throughout any mission phase as well as the ability to automatically schedule operations in case of emergency. Furthermore, Opt-OS can be used in conjunction with multi-objective optimisation tools for performing full system optimisation. Based on the optimal operations schedule, subsystem design parameters are being optimised in order to achieve the maximal usage of the satellite while keeping its mass minimal

    European retrievable carrier (Eureca) and evolutionary space carrier for microgravity, Earth observation and technology demonstration

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    The Spacelab relatively short stay-time in orbit has led to consideration of the European Retrievable Carrier (EURECA) concept as a reusable carrier. The EURECA concept is a free-flying carrier of experiments which is launched and recovered by the space shuttle. It is commensurate with the size of payloads that can be economically developed in Europe and combines the advantages of Spacelab (high mass and power capability, recovery) with those of a free flyer (extended operating time in a non-polluted environment). The launch of the first EURECA mission is scheduled for October 1987. The Eureca spacecraft will be deployed from the Shuttle cargo bay in orbit, will operate in a free-flying mode for about six months, and will then be retrieved, together with its payloads, returned to Earth by the Space Shuttle and prepared for the next mission. The first mission of EURECA is dedicated to research in the fields of life sciences and material sciences. The experimental hardware of the first mission consist of a variety of processin chambers for crystal growth and equipment for biological investigations viz plant growth and protein crystallization, and there is the possibility to perform experiments in the field of exobiology

    HILT IV : subject interoperability through building and embedding pilot terminology web services

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    A report of work carried out within the JISC-funded HILT Phase IV project, the paper looks at the project's context against the background of other recent and ongoing terminologies work, describes its outcome and conclusions, including technical outcomes and terminological characteristics, and considers possible future research and development directions. The Phase IV project has taken HILT to the point where the launch of an operational support service in the area of subject interoperability is a feasible option and where both investigation of specific needs in this area and practical collaborative work are sensible and feasible next steps. Moving forward requires detailed work, not only on terminology interoperability and associated service delivery issues, but also on service and end user needs and engagement, service sustainability issues, and the practicalities of interworking with other terminology services and projects in UK, Europe, and global contexts

    Libraries in transition: evolving the information ecology of the Learning Commons: a sabbatical report

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    This sabbatical report studied various models in order to determine best practices for design, implementation and service of Leaning Commons, a library service model which functionally and spatially integrates library services, information technology services, and media services to provide a continuum of services to the user

    Evaluating application prototypes in the automobile

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    Implementation and evaluation of the sensornet protocol for Contiki

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    Sensornet Protocol (SP) is a link abstraction layer between the network layer and the link layer for sensor networks. SP was proposed as the core of a future-oriented sensor node architecture that allows flexible and optimized combination between multiple coexisting protocols. This thesis implements the SP sensornet protocol on the Contiki operating system in order to: evaluate the effectiveness of the original SP services; explore further requirements and implementation trade-offs uncovered by the original proposal. We analyze the original SP design and the TinyOS implementation of SP to design the Contiki port. We implement the data sending and receiving part of SP using Contiki processes, and the neighbor management part as a group of global routines. The evaluation consists of a single-hop traffic throughput test and a multihop convergecast test. Both tests are conducted using both simulation and experimentation. We conclude from the evaluation results that SP's link-level abstraction effectively improves modularity in protocol construction without sacrificing performance, and our SP implementation on Contiki lays a good foundation for future protocol innovations in wireless sensor networks

    Computing in ST: evaluation of the present situation and plans for the future

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    A general overview of the current situation will help to define plans for the future in order to obtain maximum profit of the resources we have and to better plan future investments. The main computing issues for 1998 are presented and their effects evaluated: Migration of QuickMail towards the CERN central mail server, in parallel with a migration of MAC to PC when needed; -rationalization of the ST desktop inventory and analysis of needs for the near future; migration from RAPIER (the Computerized Maintenance system) to its latest version R5, and re-organization of the different databases concerned; extensive use of the WWW as common communication system. Also, a divisional strategy for computing is presented: standardization, choice of solutions considering that the convenient solution is not always the best technical one, importance of training in general organization and in specific domains in order to increase efficiency in daily work

    Review of Fault Mitigation Approaches for Deep Neural Networks for Computer Vision in Autonomous Driving

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    The aim of this work is to identify and present challenges and risks related to the employment of DNNs in Computer Vision for Autonomous Driving. Nowadays one of the major technological challenges is to choose the right technology among the abundance that is available on the market. Specifically, in this thesis it is collected a synopsis of the state-of-the-art architectures, techniques and methodologies adopted for building fault-tolerant hardware and ensuring robustness in DNNs-based Computer Vision applications for Autonomous Driving

    European Commission Initiative on Breast Cancer (ECIBC): Plenary 2016

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    The European Commission Initiative on Breast Cancer (ECIBC) Plenaries are an opportunity to inform representatives from the 28 EU Member States and 7 other countries participating in the ECIBC, as well as patients and other stakeholders, policymakers, and the scientific and health policy communities, about the aims, activities and achievements of the ECIBC. They also provide a platform for the exchange of ideas, feedback and input into the ECIBC. The 2016 ECIBC Plenary, entitled β€œWhen science and policy collaborate for health”, took place on 24-25 November in Varese, Italy. Its main focus was the implementation of both the voluntary European Quality Assurance scheme for Breast Cancer Services (European QA scheme) and the European guidelines for breast cancer screening and diagnosis (European Breast Guidelines). In this context, the first concrete results were presented, with the launch of the first four European Breast Guidelines recommendations on screening. The first day of the Plenary was dedicated to the JRC informing the audience about the various tools that ECIBC is developing. The second day instead, gave the floor to the audience, who informed the JRC of their views in terms of the challenges and opportunities related to implementing the ECIBC in the respective European countries. The event opened with welcome speeches from the European Commission’s Joint Research Centre (JRC), a moving presentation from a breast cancer survivor and reflections on how to ensure science makes its way into policy. The JRC and ECIBC working group members then brought the audience up to date with progress on the European QA scheme, the European Breast Guidelines, as well as the Guidelines Platform, the template for training on digital mammography, as well as about how ECIBC plans to monitor its impact. Participants also received in-depth explanations of the accreditation framework selected for the European QA scheme, as well as two countries’ experiences of using the ISO 15189 standard for accreditation, which is foreseen for the European QA scheme. The second day saw a focus on the individual countries represented at the Plenary. Presentations assessed how the European QA scheme could potentially fit into three different health systems (Scotland, the Netherlands, Romania), while a special breakout session gave national representatives from the 27 countries present (out of the 35 countries participating in the ECIBC) the chance to discuss implementation of the European Breast Guidelines and the European QA scheme themselves. The results, collected through questionnaires, fed into a roundtable debate on what needs to be done at European and national level to ensure ECIBC implementation. The meeting was closed by Member of the European Parliament and President of MEPs Against Cancer (MACs), Alojz Peterle. An evaluation of the event revealed that the third ECIBC Plenary met its aims to inform stakeholders: all responding participants felt that the event succeeded in providing a comprehensive overview of how the ECIBC is progressing, and what the challenges are. Discussions also provided the JRC with valuable information and feedback. The fourth ECIBC Plenary will take place once the results from piloting the European QA scheme are available.JRC.F.1-Health in Societ
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