13,101,950 research outputs found

    Impact of speed cameras on safety

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    Some reasons for lowering the legal drink-drive limit in Britain

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    The current legal limit on drivers? blood alcohol content was set at 80mg/100ml nearly 40years ago and there are now only two other Member States of the European Union, both ofthem small countries, with limits higher than 50mg/100ml. Deaths from drink driving inGreat Britain stopped falling 10 years ago, and show signs of rising. The reasons for thesetting of the current limit in 1967 and changes since then are discussed, and a fresh look istaken at the likely annual reduction in deaths on the road in Great Britain if the limit herewere lowered to 50mg/100ml. Lowering the limit is seen not as a measure to be taken inisolation, but as part of a substantial initiative to resume and sustain a clear downwardtrend in death and injury resulting from the avoidable excess risk of driving after drinking

    Travel survey data required to inform transport safety policy and practice

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    The risk of accidental death per hour spent using the roads in Hong Kong is about I I times the average risk per hour in the rest of everyday life. Other kinds of travel also have risks. Changes in travel patterns affect the numbers of people killed and injured in transport accidents. This means that all policies that affect travel patterns also affect the numbers killed and injured in transport accidents, and conversely, changing travel patterns may itself be a way of reducing these numbers. Investigation of these interactions between travel patterns and amount of death and injury in transport accidents can benefit greatly from various kinds of data that are already commonly collected in travel surveys. But the range of such investigations could be extended in useful ways if some additional items of data could be collected in travel surveys. There is also scope for the methods used in travel surveys to be extended in new ways to improve understanding of the occurrence of transport accidents and people's involvement in them by supplementing with surveys akin to travel surveys the data that are recorded when accidents occur

    Fuzzy Chance-constrained Programming Based Security Information Optimization for Low Probability of Identification Enhancement in Radar Network Systems

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    In this paper, the problem of low probability of identification (LPID) improvement for radar network systems is investigated. Firstly, the security information is derived to evaluate the LPID performance for radar network. Then, without any prior knowledge of hostile intercept receiver, a novel fuzzy chance-constrained programming (FCCP) based security information optimization scheme is presented to achieve enhanced LPID performance in radar network systems, which focuses on minimizing the achievable mutual information (MI) at interceptor, while the attainable MI outage probability at radar network is enforced to be greater than a specified confidence level. Regarding to the complexity and uncertainty of electromagnetic environment in the modern battlefield, the trapezoidal fuzzy number is used to describe the threshold of achievable MI at radar network based on the credibility theory. Finally, the FCCP model is transformed to a crisp equivalent form with the property of trapezoidal fuzzy number. Numerical simulation results demonstrating the performance of the proposed strategy are provided

    Quadrature Phase Shift Keying (QPSK) Modulator Design using Multi-Port Network in Multilayer Microstrip-Slot Technology for Wireless Communication Applications

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    The design of the quadrature phase shift keying (QPSK) modulator by using a multi-port network is proposed in this article for the use in wireless communication applications. The multi-port network is in the form of multilayer microstrip-slot technology. This multi-port network is composed of three 3-dB rectangular-shaped directional couplers with virtual stubs and an equal power division divider with in-phase characteristic. The design is performed by applying a full-wave electromagnetic simulation software, CST Microwave Studio (CST MWS). Keysight’s Advanced Design System (ADS) is applied in analyzing and evaluating the QPSK constellation of the proposed modulator. This comparatively small size of proposed design has been fabricated, and its wideband performance of 2 to 6 GHz is verified

    Uplink Multiuser MIMO Detection Scheme with Reduced Computational Complexity

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    The wireless communication systems with multiple antennas have recently received significant attention due to their higher capacity and better immunity to fading channels as compared to single antenna systems. A fast antenna selection scheme has been introduced for the uplink multiuser multiple-input multiple-output (MIMO) detection to achieve diversity gains, but the computational complexity of the fast antenna selection scheme in multiuser systems is very high due to repetitive pseudo-inversion computations. In this paper, a new uplink multiuser detection scheme is proposed adopting a switch-and-examine combining (SEC) scheme and the Cholesky decomposition to solve the computational complexity problem. K users are considered that each users is equipped with two transmit antennas for Alamouti space-time block code (STBC) over wireless Rayleigh fading channels. Simulation results show that the computational complexity of the proposed scheme is much lower than the systems with exhaustive and fast antenna selection, while the proposed scheme does not experience the degradations of bit error rate (BER) performances

    A Memristor as Multi-Bit Memory: Feasibility Analysis

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    The use of emerging memristor materials for advanced electrical devices such as multi-valued logic is expected to outperform today's binary logic digital technologies. We show here an example for such non-binary device with the design of a multi-bit memory. While conventional memory cells can store only 1 bit, memristors-based multi-bit cells can store more information within single device thus increasing the information storage density. Such devices can potentially utilize the non-linear resistance of memristor materials for efficient information storage. We analyze the performance of such memory devices based on their expected variations in order to determine the viability of memristor-based multi-bit memory. A design of read/write scheme and a simple model for this cell, lay grounds for full integration of memristor multi-bit memory cell

    Split Distributed Computing in Wireless Sensor Networks

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    We designed a novel method intended to improve the performance of distributed computing in wireless sensor networks. Our proposed method is designed to rapidly increase the speed of distributed computing and decrease the number of the messages required for a network to achieve the desired result. In our analysis, we chose Average consensus algorithm. In this case, the desired result is that every node achieves the average value calculated from all the initial values in the reduced number of iterations. Our method is based on the idea that a fragmentation of a network into small geographical structures which execute distributed calculations in parallel significantly affects the performance

    Understanding business strategies of networked value constellations using goal- and value modeling

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    In goal-oriented requirements engineering (GORE), one usually proceeds from a goal analysis to a requirements specification, usually of IT systems. In contrast, we consider the use of GORE for the design of IT-enabled value constellations, which are collections of enterprises that jointly satisfy a consumer need using information technology. The requirements analysis needed to do such a crossorganizational design not only consists of a goal analysis, in which the relevant strategic goals of the participating companies are aligned, but also of a value analysis, in which the commercial sustainability of the constellation is explored. In this paper we investigate the relation between strategic goal- and value modeling. We use theories about business strategy such as those by Porter to identify strategic goals of a value constellation, and operationalize these goals using value models. We show how value modeling allows us to find more detailed goals, and to analyze conflicts among goals
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