134 research outputs found
Problems for Vulnerable Road Users in Great Britain
INTRODUCTION
In Britain pedal cycle and, in particular, pedestrian travel are important transport modes for the population. However, given the vulnerable nature of these modes of transport, the number of accidents involving pedestrians and cyclists is high, and in particular the number of killed and seriously injured victims is high. Technical measures to improve safety and efficiency focus almost exclusively on motorized traffic, disregarding the needs of non-motorized traffic participants. In order to determine how technical measures, such as Road Traffic Informatics (RTI) applications, can be used to increase the safety and mobility of pedestrians and cyclists, more information is needed about the causes of accidents to these groups.
This report aims to look at a number of the attributes of accidents which involve vulnerable road users and at the characteristics of their travel, in order to identify areas where safety and mobility improvements may be obtained. It is intended to serve as a tool in subsequent stages of this project, and thus is not a general survey of safety and mobility problems for vulnerable road users, but rather a review of those issues that are related to the RTI measures envisaged by the project. The project is aimed at improving VRU safety and mobility both directly, through the enhancement of signalized junctions and pedestrian crossings, and indirectly, through the creation of a model of the traffic system incorporating vulnerable road users. It is intended that this model will permit the routing and guidance of motorized vehicles in such a way as to enhance VRU safety and reduce VRU annoyance and delay from trfic. Both the direct and the indirect measures envisaged will only be relevant to VRU safety and mobility on main roads in urban areas; they are unlikely to be applicable to residential streets or minor roads unless these have substantial VRU flows. The report therefore concentrates (in so far as existing information permits) on VRU safety and mobility on main roads and on VRU use of facilities that are intended to be upgraded through the planned RTI measures.
The report is split into two main sections; the first of which will examine safety and mobility problems for vulnerable road users on a national level, and the second will examine safety and mobility problems for vulnerable road users at a more local level, specifically for Bradford in West Yorkshire. Parallel reports are being produced for Sweden and The Netherlands, which will examine the situations regarding the safety and mobility of vulnerable roads users in those countries as a whole, and in one urban area from each (namely the town of Vaxjo in Sweden and the City of Groningen in The Netherlands)
A radiant heating test facility for space shuttle orbiter thermal protection system certification
A large scale radiant heating test facility was constructed so that thermal certification tests can be performed on the new generation of thermal protection systems developed for the space shuttle orbiter. This facility simulates surface thermal gradients, onorbit cold-soak temperatures down to 200 K, entry heating temperatures to 1710 K in an oxidizing environment, and the dynamic entry pressure environment. The capabilities of the facility and the development of new test equipment are presented
Problems for Vulnerable Road Users in Great Britain, The Netherlands and Sweden
INTRODUCTION
In many countries in Europe pedal cycle and pedestrian travel are important transport modes for the population. However, given the vulnerable nature of these modes of transport, the number of accidents involving pedestrians and cyclists is high, and in particular the number of killed and seriously iDjured victims is high. Technical measures to improve safety and efficiency focus almost exclusively on motorized traf£ic, disregarding the needs of non-motorized traffic participants. In order to determine how technical measures, such as Road Trac Informatics (RTI) applications, can be used to increase the safety and mobility of pedestrians and cyclists, more information is needed about the causes of accidents to these groups.
The aim of this report is to compare the hdings of three previous reports (Tight, Carsten and Sherborne, 1989; Van Schagen and Rothengatter, 1989; and Ekman and Draskhy, 1989), which examined the problems faced by vulnerable road users (VRUs) in Britain, the Netherlands and Sweden, and in one city from each of those countries, namely Bradford, Groningen and VGo. The aim of these reports was to examine a number of the attributes of accidents which involve VRUs and the charaderistics of their travel, in order to identify areas where safety and mobility improvements may be obtained. It is not intended that this report should provide a general comparison of the safety and mobility problems faced by VRUs in the three countries, but rather a review of those issues that are related to the RTI measures envisaged by the present research programme (DRIVE Project V1031). This project is aimed at improving VRU safety and mobility both directly, through the enhancement of signalized junctions and pedestrian crossings, and indirectly, through the creation of a model of the traffic system incorporating vulnerable road users. It is intended that this model will permit the routing and guidance of motorized vehicles in such a way as to enhance VRU safety and reduce VRU annoyance and delay from traffic. Both the direct and the indirect measures envisaged will only be relevant to VRU safety and mobility on main roads in urban areas; they are unlikely to be applicable to residential streets or minor roads unless these have substantial VRU flows. The report therefore concentrates (in so far as existing information permits) on VRU safety and mobility on main roads and on VRU use of facilities that are intended to be upgraded through the planned RTI measures.
This report is split into two main sections, the first of which examines comparisons of safety and mobility at the national level, and the second examines such comparisons at the local (city) level. The analyses undertaken in this report concerning the national level are largely based upon published information, while at the local level, due mainly to the lack of any regularly published information, a number of special tabulations have been made. The information given in the tables is for the most up-to-date year available.
As with most international comparisons, this study encountered a number of compatibility problems when trying to bring together data from the three countries involved. These included problems of definition, problems of interpretation and differences in the levels of inaccuracy and underreporting of accident statistics. It is not intended to expand upon the possible effects of such problems at this point, as these have been adequately covered in other reports (see for example Tight et al, 1986). Where possible comparable data have been used in the analyses which follow, however on occasions it was not possible to produce exactly comparable data, and in such cases mention is made of this in the text
CacheMAsT: Cache Management Analysis and Visualization Tool
Recent approaches have proposed to empower Internet Service Providers (ISPs) with caching capabilities that can allow them to implement their own cache management strategies and as such have better control over the utilization of their resources. In this demo paper, we present CacheMAsT (Cache Management Analysis and Visualization Tool), a decision support tool to visualize the configuration and performance of in-network cache management approaches. CacheMAsT is aimed at assisting researchers and engineers in analyzing and evaluating the different factors that can affect the performance of a cache management strategy and ultimately decide on the optimal approach to apply
Thermal certification tests of Orbiter Thermal Protection System tiles coated with KSC coating slurries
Thermal tests of Orbiter thermal protection system (TPS) tiles, which were coated with borosilicate glass slurries fabricated at Kennedy Space Center (KSC), were performed in the Radiant Heat Test Facility and the Atmospheric Reentry Materials & Structures Evaluation Facility at Johnson Space Center to verify tile coating integrity after exposure to multiple entry simulation cycles in both radiant and convective heating environments. Eight high temperature reusable surface insulation (HRSI) tiles and six low temperature reusable surface insulation (LRSI) tiles were subjected to 25 cycles of radiant heat at peaked surface temperatures of 2300 F and 1200 F, respectively. For the LRSI tiles, an additional cycle at peaked surface temperature of 2100 F was performed. There was no coating crack on any of the HRSI specimens. However, there were eight small coating cracks (less than 2 inches long) on two of the six LRSI tiles on the 26th cycle. There was practically no change on the surface reflectivity, physical dimensions, or weight of any of the test specimens. There was no observable thermal-chemical degradation of the coating either. For the convective heat test, eight HRSI tiles were tested for five cycles at a surface temperature of 2300 F. There was no thermal-induced coating crack on any of the test specimens, almost no change on the surface reflectivity, and no observable thermal-chemical degradation with an exception of minor slumping of the coating under painted TPS identification numbers. The tests demonstrated that KSC's TPS slurries and coating processes meet the Orbiter's thermal specification requirements
Access to a diverse array of bridged benzo[1,5]oxazocine and benzo[1,4]diazepine structures
The preparation of bridged benzo[1,5]oxazocines and benzo[1,4]diazepines is demonstrated from simple aniline and aldehyde starting materials. A one-pot condensation/6Ï€ electrocyclization is followed by an intramolecular trapping of the 2,3-dihydroquinoline intermediate by nitrogen or oxygen nucleophiles to give bridged seven- and eight-membered products. Using 3-hydroxypyridinecarboxaldehydes results in a stable zwitterionic structure that can undergo a diastereoselective reduction under hydrogenative conditions. A similar cyclization/hydrogenation pathway with excellent diastereoselectivity is also demonstrated from 2-pyridyl-substituted 1,2,3,4-tetrahydroquinolines.PostprintPeer reviewe
On the Impact of Fixed Point Hardware for Optical Fiber Nonlinearity Compensation Algorithms
Nonlinearity mitigation using digital signal processing has been shown to increase the achievable data rates of optical fiber transmission links. One especially effective technique is digital back propagation (DBP), an algorithm capable of simultaneously compensating for linear and nonlinear channel distortions. The most significant barrier to implementing this technique, however, is its high computational complexity. In order to fully characterize the performance of DBP, there is a need to model the algorithm under the constraint of a fixed hardware complexity which, crucially, would include the bit-depth of the multiplication operation. In this work, DBP and a single nonlinear step DBP implementation, the Enhanced Split Step Fourier method (ESSFM), are compared with linear equalization using a generic software model of fixed point hardware. The requirements of bit depth and fast Fourier transform (FFT) size are discussed to examine the optimal operating regimes for these two schemes of digital nonlinearity compensation. For a 1000 km transmission system, it was found that (assuming an optimized FFT size), in terms of SNR, the ESSFM algorithm outperformed the conventional DBP for all hardware resolutions up to 13 bits
Undefined familial colorectal cancer and the role of pleiotropism in cancer susceptibility genes.
Although family history is a major risk factor for colorectal cancer (CRC) a genetic diagnosis cannot be obtained in over 50Â % of familial cases when screened for known CRC cancer susceptibility genes. The genetics of undefined-familial CRC is complex and recent studies have implied additional clinically actionable mutations for CRCÂ in susceptibility genes for other cancers. To clarify the contribution of non-CRC susceptibility genes to undefined-familial CRC we conducted a mutational screen of 114 cancer susceptibility genes in 847 patients with early-onset undefined-familial CRC and 1609 controls by analysing high-coverage exome sequencing data. We implemented American College of Medical Genetics and Genomics standards and guidelines for assigning pathogenicity to variants. Globally across all 114 cancer susceptibility genes no statistically significant enrichment of likely pathogenic variants was shown (6.7Â % cases 57/847, 5.3Â % controls 85/1609; PÂ =Â 0.15). Moreover there was no significant enrichment of mutations in genes such as TP53 or BRCA2 which have been proposed for clinical testing in CRC. In conclusion, while we identified genes that may be considered interesting candidates as determinants of CRC risk warranting further research, there is currently scant evidence to support a role for genes other than those responsible for established CRC syndromes in the clinical management of familial CRC
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