16 resultados para roadside hawk

em QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast


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This paper uses Ridley Scott’s 2001 film blockbuster Black Hawk Down to examine the claim that popular film is the ‘newest component of sovereignty’. While the topic of the film – the 1993 UN/US intervention in Somalia – lends itself to straightforward politicisation, this paper is equally interested in the film’s production history and its reception by global audiences. While initial reactions to the film focused on its ideological commitments (e.g. racism, collusion between Hollywood and the Pentagon, post-11 September patriotism), these readings continually posed an imagined ‘America’ against ‘the world’. This paper argues that Black Hawk Down is not about sovereignty as traditionally conceived, that is, about national interest shaping global affairs. Rather, Black Hawk Down articulates, and is articulated by, a new and emerging global order that operates through inclusion, management and flexibility. Drawing on recent theoretical debates over this new logic of rule, this paper illustrates how Black Hawk Down invoked much more diffuse, complex and deterritorialized categories than national sovereignty. In effect, Scott’s film goes beyond traditional notions of sovereignty altogether: its production, signification and reception deconstruct simple notions of ‘America’ and ‘the world’ in favour of what Hardt and Negri call ‘Empire’, what Zizek calls ‘post-politics’, and what we refer to as ‘meta-sovereignty’.

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In this paper, a novel method for modelling a scaled vehicle–barrier crash test similar to the 20◦ angled barrier test specified in EN 1317 is reported. The intended application is for proof-of-concept evaluation of novel roadside barrier designs, and as a cost-effective precursor to full-scale testing or detailed computational modelling. The method is based on the combination of the conservation of energy law and the equation of motion of a spring mass system representing the impact, and shows, for the first time, the feasibility of applying classical scaling theories to evaluation of roadside barrier design. The scaling method is used to set the initial velocity of the vehicle in the scaled test and to provide scaling factors to convert the measured vehicle accelerations in the scaled test to predicted full-scale accelerations. These values can then be used to calculate the Acceleration Severity Index score of the barrier for a full-scale test. The theoretical validity of the method is demonstrated by comparison to numerical simulations of scaled and full-scale angled barrier impacts using multibody analysis implemented in the crash simulation software MADYMO. Results show a maximum error of 0.3% ascribable to the scaling method.

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This paper evaluates the potential of gabions as roadside safety barriers. Gabions have the capacity to blend into natural landscape, suggesting that they could be used as a safety barrier for low-volume road in scenic environments. In fact, gabions have already been used for this purpose in Nepal, but the impact response was not evaluated. This paper reports on numerical and experimental investigations performed on a new gabion barrier prototype. To assess the potential use as a roadside barrier, the optimal gabion unit size and mass were investigated using multibody analysis and four sets of 1:4 scaled crash tests were carried out to study the local vehicle-barrier interaction. The barrier prototype was then finalised and subjected to a TB31 crash test according to the European EN1317 standard for N1 safety barriers. The test resulted in a failure due to the rollover of the vehicle and tearing of the gabion mesh yielding a large working width. It was found that although the system potentially has the necessary mass to contain a vehicle, the barrier front face does not have the necessary stiffness and strength to contain the gabion stone filling and hence redirect the vehicle. In the EN1317 test, the gabion barrier acted as a ramp for the impacting vehicle, causing rollover. 

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In this paper the tracking system used to perform a scaled vehicle-barrier crash test is reported. The scaled crash test was performed as part of a wider project aimed at designing a new safety barrier making use of natural building materials. The scaled crash test was designed and performed as a proof of concept of the new mass-based safety barriers and the study was composed of two parts: the scaling technique and of a series of performed scaled crash tests. The scaling method was used for 1) setting the scaled test impact velocity so that energy dissipation and momentum transferring, from the car to the barrier, can be reproduced and 2) predicting the acceleration, velocity and displacement values occurring in the full-scale impact from the results obtained in a scaled test. To achieve this goal the vehicle and barrier displacements were to be recorded together with the vehicle accelerations and angular velocities. These quantities were measured during the tests using acceleration sensors and a tracking system. The tracking system was composed of a high speed camera and a set of targets to measure the vehicle linear and angular velocities. A code was developed to extract the target velocities from the videos and the velocities obtained were then compared with those obtained integrating the accelerations provided by the sensors to check the reliability of the method.

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Run Off Road (ROR) crashes are road accidents that often result in severe injuries or fatalities. To reduce the severity of ROR crashes, “forgiving roadsides” need to be designed and this includes identifying situations where there is a need for a Vehicle Restraint System (VRS) and what appropriate VRS should be selected for a specific location and traffic condition. Whilst there are standards covering testing, evaluation and classification of VRS within Europe (EN1317 parts 1 to 8), their selection, location and installation requirements are typically based upon national guidelines and standards, often produced by National Road Authorities (NRA) and/or overseeing organisations. Due to local conditions, these national guidelines vary across Europe.
The European SAVeRS project funded by CEDR has developed a practical and readily understandable VRS guidance document and a user-friendly software tool which allow designers and road administrations to select the most appropriate solution in different road and traffic conditions.
This paper describes the main outcomes of the project, the process to select the most appropriate roadside barrier, and the user friendly SAVeRS tool.

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Various game theory models have been used to explain animal contests. Here we attend to the presumed cognitive abilities required by these models with respect to information gathering and consequent decision making. Some, such as the hawk/dove game and self-assessment models require very limited cognitive ability. By contrast, the broadly accepted sequential assessment model requires that contestants know their own abilities and compare them with information gathered about their opponent to determine which has the greater resource-holding power. However, evidence for assessment of relative abilities is sparse and we suggest that this complex ability is probably beyond most animals. Indeed, perceptual limitations may restrict information about an individual's own displays and thus preclude comparison. We take a parsimonious view and conclude that simple summation of causal factors accounts for changes in fight motivation without requiring mutual evaluation of relative abilities. © 2012 The Association for the Study of Animal Behaviour.

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Gabions are stone-filled wire containers which are frequently used as retaining walls. However, due to their high mass, relatively low cost and visual appeal, a row of single gabion blocks, joined at the ends, has the potential to be used as a roadside impact absorption device where traditional steel or concrete devices may not be suitable. To evaluate such application, the shear and bending deformation of gabions under vehicle impact need to be investigated. In this paper, the shear response of a single gabion block is analytically modelled and a gabion beam multibody model is developed using a discretisation method to capture the deformability of the gabion structure. The material properties of the gabion beam are adopted from experimental values available in the literature and the modelling is statically validated over a three-point bending test and a distributed loading test. The results show that the discretised multibody modelling can be effectively used to describe the static deformation behaviour of gabion blocks.

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In this paper we investigate the first order characteristics of the radio channel between a moving vehicle and a stationary person positioned by the side of a road at 5.8 GHz. The experiments considered a transmitter positioned at different locations on both the body and receivers positioned on the vehicle. The transmitter was alternated between positions on the central chest region, back and the wrist (facing the roadside) of the body, with the receivers placed on the outside roof, the outside rear window and the inside dashboard of the vehicle. The Rice fading model was applied to the measurement data to assess its suitability for characterizing this emerging type of wireless channel. The Ricean K factors calculated from the data suggest that a significant dominant component existed in the majority of the channels considered in this study.

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In recent years, the embracement of smart devices carried or worn by people have transformed how society interact with one another. This trend has also been observed in the advancement of vehicular networks. Here, developments in wireless technologies for vehicle-to-vehicle (V2V) and vehicle-to-roadside (V2R) communications are leading to a new generation of vehicular networks. A natural extension of both types of networks will be their eventual wireless integration. Both people and vehicles will undoubtedly form integral parts of future mobile networks of people and things. Central to this will be the person-to-vehicle (P2V) communications channel. As the P2V channel will be subject to different signal propagation characteristics than either type of communication system considered in isolation, it is imperative the characteristics of the wireless channel must first be fully understood. To the best of the author's knowledge, this is a topic which has not yet been addressed in the open literature. In this paper we will present our most recent research on the statistical characterization of the 5.8 GHz person-to-vehicle channel in an urban environment.