2,402 research outputs found

    Secure Vehicular Communication Systems: Implementation, Performance, and Research Challenges

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    Vehicular Communication (VC) systems are on the verge of practical deployment. Nonetheless, their security and privacy protection is one of the problems that have been addressed only recently. In order to show the feasibility of secure VC, certain implementations are required. In [1] we discuss the design of a VC security system that has emerged as a result of the European SeVeCom project. In this second paper, we discuss various issues related to the implementation and deployment aspects of secure VC systems. Moreover, we provide an outlook on open security research issues that will arise as VC systems develop from today's simple prototypes to full-fledged systems

    Electronic and magnetic properties of GaMnAs: Annealing effects

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    The effect of short-time and long-time annealing at 250C on the conductivity, hole density, and Curie temperature of GaMnAs single layers and GaMnAs/InGaMnAs heterostructures is studied by in-situ conductivity measurements as well as Raman and SQUID measurements before and after annealing. Whereas the conductivity monotonously increases with increasing annealing time, the hole density and the Curie temperature show a saturation after annealing for 30 minutes. The incorporation of thin InGaMnAs layers drastically enhances the Curie temperature of the GaMnAs layers.Comment: 4 pages, 6 figures, submitted to Physica

    Investigating well-being, work limitations and preferences for self-management education and peer support among younger people with hip and knee osteoarthritis: protocol for a cross-sectional study

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    Introduction:&nbsp;Osteoarthritis (OA) has traditionally&nbsp;been considered a condition of older age. However,&nbsp;younger people are also affected by hip and knee OA,&nbsp;often as a result of sporting and work-related injuries.&nbsp;As OA studies have generally focused on older&nbsp;individuals, little is known about the experience of&nbsp;younger adults with hip or knee OA who can face a&nbsp;distinct set of pressures including work responsibilities&nbsp;and parenting roles. This study aims to investigate&nbsp;well-being and work participation among younger&nbsp;people with hip or knee OA, as well as preferences for&nbsp;OA education and support.Methods and analysis: 200 people aged 20&ndash;55 years with a diagnosis of hip and/or knee OA will be&nbsp;recruited for this cross-sectional study. Participants will&nbsp;be recruited from three major public hospitals in the&nbsp;state of Victoria, Australia following screening of&nbsp;orthopaedic outpatient clinic lists and referrals, and&nbsp;through community-based advertisements. A study&nbsp;questionnaire will be mailed to all participants and&nbsp;written informed consent obtained. Validated measures&nbsp;of Health-Related Quality of Life (HRQoL), health status,&nbsp;psychological distress and work limitations will be used. Information on health services use will be collected,&nbsp;in addition to information on the perceived utility and&nbsp;accessibility of a range of existing and proposed&nbsp;education and peer support models. HRQoL data will be&nbsp;compared with Australian population norms using&nbsp;independent t tests, and associations between HRQoL,&nbsp;health status, psychological distress, work limitations&nbsp;and demographic factors will be evaluated using&nbsp;univariate and multivariate analyses. Data on the&nbsp;perceived utility and accessibility of education and peer&nbsp;support models will be analysed descriptively.&nbsp;Ethics and dissemination: Ethics approval for the&nbsp;study has been obtained. The study findings will be&nbsp;submitted to peer-reviewed journals and arthritis&nbsp;consumer organisations for broader dissemination, and&nbsp;presented at national and international scientific meetings.</div

    Effect of annealing on the depth profile of hole concentration in (Ga,Mn)As

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    The effect of annealing at 250 C on the carrier depth profile, Mn distribution, electrical conductivity, and Curie temperature of (Ga,Mn)As layers with thicknesses > 200 nm, grown by molecular-beam epitaxy at low temperatures, is studied by a variety of analytical methods. The vertical gradient in hole concentration, revealed by electrochemical capacitance-voltage profiling, is shown to play a key role in the understanding of conductivity and magnetization data. The gradient, basically already present in as-grown samples, is strongly influenced by post-growth annealing. From secondary ion mass spectroscopy it can be concluded that, at least in thick layers, the change in carrier depth profile and thus in conductivity is not primarily due to out-diffusion of Mn interstitials during annealing. Two alternative possible models are discussed.Comment: 8 pages, 8 figures, to appear in Phys. Rev.
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