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1.
In order to meet safety, reliability and availability constraints for passenger transport systems, the manufacturers of railway control-command systems must develop specific computer architectures for signalling, switch control and automatic driving applications. Typically, these systems consist of a core (with one or two central processing units) and peripherals via which the computer communicates with external devices. In the case of some applications, for example signal boxes, the architecture contains a very large number of fail-safe True or False outputs. These functionalities are currently performed by conventional technology that uses discrete components or hybrid circuitry.  相似文献   

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A scenario for a suburban automated highway with the objective of reducing congestion is described. Starting from a reference situation similar to a current traffic lane, the authors consider the influence of a number of parameters on the achievable capacity of an automated section of road. These parameters are used to estimate safe following distances which are computed with the aim of avoiding collisions in the event of sudden braking. They then consider the number of collisions in the presence of a brick wall type obstacle on the carriageway. Ramp metering based on a macroscopic approach leads to a loss of capacity, which we overcome by implementing a management technique that integrates individual vehicles in the stream. Lastly, a general architecture for the scenario with several control and co-ordination layers is proposed.  相似文献   

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This paper presents a socioeconomic examination of the project for a fixed link in the Strait of Gibralter. This project for a major link between Europe and the Maghreb which would take the form of a rail tunnel can be examined at two different spatial scales, that of the major trade networks which link Europe and the Maghreb and that of the areas which are located near the future points of access to the tunnel. If we pass over the problems which may be posed by the financing of this project (which studies have shown to be profitable), the geopolitical context of changing relations within Europe and the Mediterranean should be favourable to its construction. Its strategic (and at the same time symbolic) character is defined by its role as a link between the trans-European networks and the southwestern shore of the Mediterranean basin. This physical connection may nevertheless generate undesired or even counterproductive effects in the directly exposed economies on the southern side. Additional strategies could be considered for which the existence of a tunnel would constitute an opportunity. These are referred to as accompanying measures in French regional planning policy.  相似文献   

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Traffic noise is usually measured at fixed points whereas in reality vehicles move and generate noise throughout their trip. This paper therefore puts forward a new method of identifying noise emissions which takes account of the trip as a whole. We have made use of the concept of standard kinematic sequences (which are the elements which form all car trips) and have introduced a new acoustic index to characterize the noise emissions of a vehicle during a sequence. We have achieved this by adapting conventional highway acoustic indices to the way sequences are defined and used. We have calculated examples of these indices from acoustic recordings of isolated vehicles on a test track and from standard sequences.  相似文献   

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One of the factors which discourages use of public transport is the feeling of insecurity. In order to overcome this, the operators of metro networks are attempting to find techniques to detect more incidents or anomalies rapidly. It is within this framework, as part of the European cromatica project, that research has been undertaken at inrets by the video team in the Traffic Analysis and Control Department (dart). This paper will concentrate on the detection of abnormal stationarities in metro corridors. Operators wish to identify events of this type as a prolonged stationarity may denote the presence of a drug pusher, an illicit vendor, a thief watching a potential victim, a homeless person, a person suffering from illness, a person who has had a fall, or an abandoned object. The paper firstly gives an account of the developed system and its context and then describes the image processing techniques which have been used. The results obtained with real complex situations are then presented.  相似文献   

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Models that link accident frequencies at road sites with traffic volumes and road characteristics provide reference values which are of value when carrying out diagnostic studies and deciding on preventive measures. Such models can be developed using generalized linear modelling techniques, which are able to take account of the Poisson properties of accident frequencies at road sites. The Poisson models obtained for road sites are frequently everdispersed, so extended forms of the Poisson model (quasi-Poisson, negative binomial a high percentage of the studied sites, in which case zero-inflated models also have to be considered. This paper presents an overview of these methods which are illustrated by modelling the relationship between accident frequency site characteristics and traffic volume on a large sample of bends.  相似文献   

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记得2009年10月21-11月4日举行的第41届东京车展吗?展会上,雅马哈引荐了一款围巾缠住车头的大型探险摩托车,犹抱琵琶半遮面的造型让人心痒难搔。现在,雅马哈终于揭去神秘的面纱,这就是震撼出击、剑锋直指杜卡迪Multistrada1200的全新大型探险旅行摩托车XT1200ZTénéré!  相似文献   

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The knowledge about the proportion of household budget which Africans spend on urban transport is still poor. We have carried out an analysis of a household travel survey to provide some insight into this topic. This paper begins with a review of the literature that illustrates how much different estimates vary and goes on to discuss the effects of a number of methodological decisions, with regard to be robust, in particular as far as to expenditure is recorded, the type of data collection and the selection of an equivalence scale. With regard to an application in the city of Niamey, the authors explain the hypotheses they have made and describe sensitivity tests when different equivalence scales are applied. Although it would seem that travel surveys could benefit from methodological improvements, the results appear to be robust, in particular as far as selection of an equivalence scale is concerned. Because of high running costs, motor vehicle ownership is extremely restricted. Public transport use is a substitute for personal modes, but it is also expensive and a considerable burden on the budgets of the poorest households. Its use is therefore constrained, which limits the ability of low income groups for become truly integrated within the economic and social life the city  相似文献   

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方飞云 《摩托车》2010,(4):42-45
记得2009年10月21-11月4日举行的第41届东京车展吗?展会上,雅马哈引荐了一款围巾缠住车头的大型探险摩托车,"犹抱琵琶半遮面"的造型让人心痒难搔。现在,雅马哈终于揭去神秘的面纱,这就是震撼出击、剑锋直指杜卡迪Multistrada1200的全新大型探险旅行摩托车XT1200Z Ténéré!  相似文献   

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This study was carried out on a population of 127 offending drivers of both sexes. A validation study was also performed on a sample of 51 offending drivers of both sexes. On the basis of a questionnaire that dealt with road related parameters (violations accidents, vehicle power) and use of the Guilford Zimmermann Temperament. Survey (with the Parenti driving questionnaire in the validation study), a variety of analyses were conducted which demonstrated essentially that offending drivers do not posses a specific psycholonical profile, (unlike motorcycle and HGV licence holders who do). However, it emerged that men and women have a different relationship with the car which is an object of narcissistic investment for men, contributing to their image and self-esteem and becoming a means or supporting and asserting their masculine identity) and that the intensification of male identity is associated with a variety of behaviours that increase the risk of both violations and accidents. Furthermore, while violations in themselves are not predictive of risk, perhaps revealing more about the nature of surveillance activities, frequent reoffending can lead to the assumption that the individuals are potentially dangerous drivers.  相似文献   

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雷诺Mégane     
《世界汽车》2002,(2):61-64
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Generalized linear models provide a unifying framework which permits application of most of the interential methods that can be used to evaluate the impact of a road safety, measure. When observations are available before and after the introduction of the measure (i.e., when there is an experimental sample and a control sample which covers the same period which indicates what would have hapened if the measure had not been introduced, the difference between the two samples can be characterized d'using the appropriate interaction term. The models used estimate relative risk or incidence rates and are able to take into account a reasonable number of confounding factors. These methods have been applied in order to compace the severity of impacts with metal guardrails or concreté safety barriers on motorway central reservations. Poisson regression modelling has revealed a tendency for the risk of injury to be higher on road sections where concréte devices have a recently been installed. Multivariate analysis using logistic regression with adjustment with reference to certain factor for example a change in the number of lanes or the occurrence of a second impact shows that concrete barrier significantly increase (by a factor or about 1.9) the risk of injury in the case of a first impact on the central reservation. This estimate could be used in a more general cost benefit analysis.  相似文献   

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《摩托车》2020,(8)
正Ténéré是非洲中西部国家尼日尔境内的沙漠,位于撒哈拉沙漠的南部中心,面积约四十万平方千米,环境特别恶劣,气候特别干燥、酷热,每年降雨量仅为25mm,是非洲最危险、最可怕的地方之一,也是达喀尔拉力赛移师南美洲之前最复杂、最困难的路段。雅马哈Ténéré700以这块最恶劣的沙漠来命名,你就会明白,这台全新亮相的中量级探险车,流淌着纯正的拉力赛血统!  相似文献   

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