49,620 research outputs found

    Ethernet - a survey on its fields of application

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    During the last decades, Ethernet progressively became the most widely used local area networking (LAN) technology. Apart from LAN installations, Ethernet became also attractive for many other fields of application, ranging from industry to avionics, telecommunication, and multimedia. The expanded application of this technology is mainly due to its significant assets like reduced cost, backward-compatibility, flexibility, and expandability. However, this new trend raises some problems concerning the services of the protocol and the requirements for each application. Therefore, specific adaptations prove essential to integrate this communication technology in each field of application. Our primary objective is to show how Ethernet has been enhanced to comply with the specific requirements of several application fields, particularly in transport, embedded and multimedia contexts. The paper first describes the common Ethernet LAN technology and highlights its main features. It reviews the most important specific Ethernet versions with respect to each application field’s requirements. Finally, we compare these different fields of application and we particularly focus on the fundamental concepts and the quality of service capabilities of each proposal

    Software-Defined Networks Supporting Time-Sensitive In-Vehicular Communication

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    Future in-vehicular networks will be based on Ethernet. The IEEE Time-Sensitive Networking (TSN) is a promising candidate to satisfy real-time requirements in future car communication. Software-Defined Networking (SDN) extends the Ethernet control plane with a programming option that can add much value to the resilience, security, and adaptivity of the automotive environment. In this work, we derive a first concept for combining Software-Defined Networking with Time-Sensitive Networking along with an initial evaluation. Our measurements are performed via a simulation that investigates whether an SDN architecture is suitable for time-critical applications in the car. Our findings indicate that the control overhead of SDN can be added without a delay penalty for the TSN traffic when protocols are mapped properly.Comment: To be published at IEEE VTC2019-Sprin

    Hedging the exchange rate risk in international portfolio diversification : currency forwards versus currency options

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    As past research suggest, currency exposure risk is a main source of overall risk of international diversified portfolios. Thus, controlling the currency risk is an important instrument for controlling and improving investment performance of international investments. This study examines the effectiveness of controlling the currency risk for international diversified mixed asset portfolios via different hedge tools. Several hedging strategies, using currency forwards and currency options, were evaluated and compared with each other. Therefore, the stock and bond markets of the, United Kingdom, Germany, Japan, Switzerland, and the U.S, in the time period of January 1985 till December 2002, are considered. This is done form the point of view of a German investor. Due to highly skewed return distributions of options, the application of the traditional mean-variance framework for portfolio optimization is doubtful when options are considered. To account for this problem, a mean-LPM model is employed. Currency trends are also taken into account to check for the general dependence of time trends of currency movements and the relative potential gains of risk controlling strategies

    Cathodoluminescence and electron microscopy of red quantum dots used for display applications

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    Cathodoluminescent imaging of the visible light emitted from quantum dots is reported. The shape and uniformity of individual particles is observed in the STEM electron image and the image of the particles created from their visible light collected simultaneously is shown. Visible light images of the 13nm sized particles are reported for clusters of particles. Emission spectra collected from a small clusters of QDs are also reported

    Source control SUDS strategic directions

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    Background to researchThe uptake or transition from traditional drainage to sustainable drainage (SUDS) in Scotland has happened in a relatively short timescale (less than fifteen years) with site and regional control drainage structures such as ponds and basins now considered ‘business as usual’. This rapid transition to SUDS has been facilitated by a stakeholder platform called the Sustainable Urban Drainage Scottish Working Party (SUDSWP) which has promoted their use since 1997. This has subsequently led to Scotland being regarded as a frontrunner in SUDS implementation in the UK. However the uptake of source control as part of a stormwater treatment train is less routine than expected. With the aforementioned in mind, this Phase Three Report seeks to answer the question ‘How can the national uptake of source control be encouraged and influenced by the SUDS Working Party and whether they should recast their remit’? Objectives of research Phase One of this research looked at the background to the evolution of source control in Scotland providing preliminary insight into the enabling factors and obstacles for uptake of the systems since inception in the mid 1990’s. Phase Two appraised source control delivery on a global scale providing insight to enabling factors out with Scotland and appraising current delivery in Scotland by responsible organisations. The transition pathway from traditional drainage to source control SUDS was mapped out to highlight what the key enabling (and disabling) factors were to realise the transition to date. This phase of the research, Phase Three defines the next steps including comment on optimal source control and further considerations and recommendations. This involved analysis and consolidation of the findings from Phases one and two, a workshop delivered to SUDSWP and two surveys delivered online and via telephone interviews with professionals involved in source control SUDS. These findings are used to define barriers and opportunities to inform the development of a strategy to support and encourage implementation of source control within SUDSWP remit.Key findings and recommendationsKey findings and recommendations for the SUDS Working Party are grouped according to transition management cluster activities:* Transition Arena: Strengthen links with internal members and external stakeholders who have a stake in source control SUDS and develop an integrated long-term vision.* Transition Agenda: Develop a shared strategic plan which considers aligning agendas with other infrastructure initiatives and enforcement / inspection policies to ensure cost effective, fit for purpose measures particularly in the areas of unit plot, local streets and regeneration areas.* Transition Experiments / case studies: Encourage research partnerships to validate techniques in the source control toolkit not yet applied in Scotland and showcase case studies.* Transition Monitoring / evaluation: undertake a baseline assessment to gauge source control uptake and performance, revise existing guidance and encourage capacity building programmes.<br/

    Match injuries in professional soccer: inter-seasonal variation and effects of competition type, match congestion and positional role

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    In this prospective observational study, injuries sustained in official match-play in players belonging to a professional soccer club were investigated. Incidence and patterns of injury were compared across four-seasons (2005-2006: S1, 2006-2007: S2, 2007-2008: S3 and 2008-2009: S4) and 3 match formats (domestic League/Cup games and European club competition). In addition, the effects of both fixture congestion and the positional role of players were investigated. Injury incidence (per 1 000 match-hours) did not vary between seasons (range 31.2-59.2 observed in S2 and S4, respectively, p=0.12) or fixture formats (range 32.6-40.8 observed in European and League matches, respectively, p=0.49). In contrast, rates varied in players (n=7) who participated in all four seasons as more injuries were sustained in S1 compared to S2 and S3, respectively (88.4 vs. 49.0 vs. 49.2, both p or = 4 days). Finally, the incidence of injury and muscle strains (both p<0.001) varied across positional roles with the highest rates observed in centre-forwards. These findings provide further knowledge on the risk of injury in contemporary professional soccer match-play and may aid in the care and management of playing resources

    An analysis of the requirements traceability problem

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    In this paper1, we investigate and discuss the underlying nature of the requirements traceability problem. Our work is based on empirical studies, involving over 100 practitioners, and an evaluation of current support. We introduce the distinction between pre-requirements specification (pre-RS) traceability and post-requirements specification (post-RS) traceability, to demonstrate why an all-encompassing solution to the problem is unlikely, and to provide a framework through which to understand its multifaceted nature. We report how the majority of the problems attributed to poor requirements traceability are due to inadequate pre-RS traceability and show the fundamental need for improvements here. In the remainder of the paper, we present an analysis of the main barriers confronting such improvements in practice, identify relevant areas in which advances have been (or can be) made, and make recommendations for research

    Identifying Critical Components During information Security Evaluations

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    Electronic communications devices intended for government or military applications must be rigorously evaluated to ensure that they maintain data confidentiality. High-grade information security evaluations require a detailed analysis of the device’s design, to determine how it achieves necessary security functions. In practice, such evaluations are labour-intensive and costly, so there is a strong incentive to find ways to make the process more efficient. In this paper we show how well-known concepts from graph theory can be applied to a device’s design to optimise information security evaluations. In particular, we use end-to-end graph traversals to eliminate components that do not need to be evaluated at all, and minimal cutsets to identify the smallest group of components that needs to be evaluated in depth
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