27,641 research outputs found

    Automatic and semi-automatic extraction of curvilinear features from SAR images

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    Extraction of curvilinear features from synthetic aperture radar (SAR) images is important for automatic recognition of various targets, such as fences, surrounding the buildings. The bright pixels which constitute curvilinear features in SAR images are usually disrupted and also degraded by high amount of speckle noise which makes extraction of such curvilinear features very difficult. In this paper an approach for the extraction of curvilinear features from SAR images is presented. The proposed approach is based on searching the curvilinear features as an optimum unidirectional path crossing over the vertices of the features determined after a despeckling operation. The proposed method can be used in a semi-automatic mode if the user supplies the starting vertex or in an automatic mode otherwise. In the semi-automatic mode, the proposed method produces reasonably accurate real-time solutions for SAR images

    ITS implementation plan for the Gold Coast area

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    ITS needs to be used to reinforce the planned major changes to the road functional hierarchy in the District, namely: • the use of Southport-Burleigh Rd. (SBR) as the major regional corridor; • the removal of through traffic from the GCH; • the use of Oxley Dr./Olsen Av./Ross St./NBR as another major north-south by-pass; • the use of Smith St.; NSR/Queen St.; NBR and Reedy Creek Rd. – West Burleigh Road as the major east-west access corridors. There is a need to integrate the proposed ITS measures into the current related plans for the Pacific Motorway and into the overall traffic control strategies for the area as a whole. In addition, the staging of the proposed plan needs to take into account the planned DMR capital Works Program. An index representing the degree of priority to be attached to each network link was developed to assist in the phased implementation of ITS technologies over the next 5 years. 'ITS Index' is made up of five variables, namely: • Accident rate factor • AADT • Volume/Capacity ratio • Delay • % Commercial Vehicles The main components of the ITS plan are shown diagrammatically in Figure 1. The latter assumes that the high level of ITS implementation on the Pacific Motorway will be extended in time to the remainder of that Highway. To assist in the implementation of the road hierarchy system, a new static signage plan should be implemented. This plan needs to reinforce the changes by clearly assigning single road names to corridors and by placing new signs at appropriate locations. Capturing Traffic Data The following corridors should be equipped with automatic traffic monitoring capability in priority order: High Priority ? SBR corridor from Smith St. connection to Reedy Creek Rd. ? Smith St. from Pacific Highway to High St. ? GCH from Pacific Highway to North St. Medium Priority ? Nerang-Broadbeach Rd/Ross St. to Nerang-Southport Rd. ? Nerang-Southport Rd from Pacific Highway to SBR ? Nerang-Broadbeach Rd from Pacific Highway to SBR The Smith St. link from the Pacific Motorway to Olsen Ave. should be considered as a freeway for monitoring purposes. The GCH along the coastal strip needs to be treated as a local distributor rather than as the major corridor. As a result, the future traffic surveillance priority should be low. At least one permanent environmental (vehicle emissions) monitoring station should be set up as part of the ITS plan. The most appropriate site for such a station would seem to be on the SBR corridor at the vicinity of Hooker Blv. intersection. Pacific Highway The Pacific Motorway project will set the benchmark for freeway incident detection and traffic management in the State. The high level of ITS implementation on the Motorway section will create a significant gap in performance and expectation, relative to the remainder of the Highway. It is recommended that the southern sections of the Pacific Highway be equipped to the equivalent level of traffic data collection and surveillance as the newly upgraded Motorway section, under a staged program. Travel Time Savings The travel time benefits of the full implementation of ITS over the network are likely to be of the order of at least 5 percent of vehicle-hours travelled on the affected links. At a discount rate of 6 percent, the total present value of the gross travel time benefit over 10 years is of the order of $200 million

    Assessment of the Effectiveness of the Greek Implementation. VRU-TOO Deliverable 14

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    The work of VRU-TOO is targeted specifically at the application of ATT for reducing risk and improving comfort (e.g. minimisation of delay) for Vulnerable Road Users, namely pedestrians. To achieve this, the project operates at three levels. At the European level practical pilot implementations in three countries (U.K., Portugal and Greece) are linked with behavioural studies of the micro-level interaction of pedestrians and vehicles and the development of computer simulation models. At the National level, the appropriate Highway Authorities are consulted, according to their functions, for the pilot implementations and informed of the results. Finally, at the local level, the pilot project work is fitted into specfic local (municipality) policy contexts in all three pilot project sites. The present report focuses on the Elefsina pilot application in Greece and the relevant National and Local policy contexts are the following. At the National level, the ultimate responsibility for road safety and signal installations rests with the Ministry of Environment and Public Works. The Ministry is responsible for the adoption of standards and solutions for problems and also for a large number of actual installations, since local authorities lack the size and expertise to undertake such work on their own One of the project's aims is to provide information to the Ministry as to the suitability of the methods developed for aiding pedestrian movement, ultimately leading to a specification for its wider use. The Ministry is expecting to use the final results of the present study for possible modifications of its present standards for pedestrian controlled traffic signals. At the local level (Elefsina) the municipality has, in the past, pursued environmental improvements through pedestrianisation schemes in the city centre. At the same time it has developed a special traffic management policy, to solve a particularly serious problem of through traffic. A summary of the policy is contained in Appendix A and more details in a previous deliverable (Tillis, 1992). In the particular case of Elefsina pedestrian induced delay to through vehicular traffic, may form a key element in this policy ensuring at the same time, an incentive to divert to the existing bypass and enhancing pedestrian movement. The effectiveness of pedestrian detection techniques tested in the pilot, will provide valuable information on the future implementation of the policy. Thus, the Elefsina Pilot Project operates at the same time on three levels: It provides a basis, in combination with the other two pilot project sites, for comparing the effects of pedestrian detection on pedestrian safety and comfort at a European level. It provides information to the National authorities (Ministry of Environment and Public Works) for their standards setting, scheme design and implementation tasks. It fits into a comprehensive plan at the local level for effecting environmental improvements and enhancing pedestrian amenity and comfort at the same time. In addition, an investigation into the capabilities of pedestrian detectors to function as data collection devices, was performed. The data 'quality gap' betweenvehicular and pedestrian tr&c may be closed with the utilisation of microwave pedestrian detectors, providing a more solid foundation for the planning for total person movement through networks (vehicle occupants, public transport passengers, pedestrians). This the second deliverable issued for Elefsina and comprises of the main section which contains a description of the work undertaken, the results and a number of appendices serving as background material in support of the statements in the main text

    Difference of Normals as a Multi-Scale Operator in Unorganized Point Clouds

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    A novel multi-scale operator for unorganized 3D point clouds is introduced. The Difference of Normals (DoN) provides a computationally efficient, multi-scale approach to processing large unorganized 3D point clouds. The application of DoN in the multi-scale filtering of two different real-world outdoor urban LIDAR scene datasets is quantitatively and qualitatively demonstrated. In both datasets the DoN operator is shown to segment large 3D point clouds into scale-salient clusters, such as cars, people, and lamp posts towards applications in semi-automatic annotation, and as a pre-processing step in automatic object recognition. The application of the operator to segmentation is evaluated on a large public dataset of outdoor LIDAR scenes with ground truth annotations.Comment: To be published in proceedings of 3DIMPVT 201

    Measuring delays for bicycles at signalized intersections using smartphone GPS tracking data

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    The article describes an application of global positioning system (GPS) tracking data (floating bike data) for measuring delays for cyclists at signalized intersections. For selected intersections, we used trip data collected by smartphone tracking to calculate the average delay for cyclists by interpolation between GPS locations before and after the intersection. The outcomes were proven to be stable for different strategies in selecting the GPS locations used for calculation, although GPS locations too close to the intersection tended to lead to an underestimation of the delay. Therefore, the sample frequency of the GPS tracking data is an important parameter to ensure that suitable GPS locations are available before and after the intersection. The calculated delays are realistic values, compared to the theoretically expected values, which are often applied because of the lack of observed data. For some of the analyzed intersections, however, the calculated delays lay outside of the expected range, possibly because the statistics assumed a random arrival rate of cyclists. This condition may not be met when, for example, bicycles arrive in platoons because of an upstream intersection. This justifies that GPS-based delays can form a valuable addition to the theoretically expected values

    Performance Measures to Assess Resiliency and Efficiency of Transit Systems

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    Transit agencies are interested in assessing the short-, mid-, and long-term performance of infrastructure with the objective of enhancing resiliency and efficiency. This report addresses three distinct aspects of New Jersey’s Transit System: 1) resiliency of bridge infrastructure, 2) resiliency of public transit systems, and 3) efficiency of transit systems with an emphasis on paratransit service. This project proposed a conceptual framework to assess the performance and resiliency for bridge structures in a transit network before and after disasters utilizing structural health monitoring (SHM), finite element (FE) modeling and remote sensing using Interferometric Synthetic Aperture Radar (InSAR). The public transit systems in NY/NJ were analyzed based on their vulnerability, resiliency, and efficiency in recovery following a major natural disaster

    Accident Analysis and Prevention: Course Notes 1987/88

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    This report consists of the notes from a series of lectures given by the authors for a course entitled Accident Analysis and Prevention. The course took place during the second term of a one year Masters degree course in Transport Planning and Engineering run by the Institute for Transport Studies and the Department of Civil Engineering at the University of Leeds. The course consisted of 18 lectures of which 16 are reported on in this document (the remaining two, on Human Factors, are not reported on in this document as no notes were provided). Each lecture represents one chapter of this document, except in two instances where two lectures are covered in one chapter (Chapters 10 and 14). The course first took place in 1988, and at the date of publication has been run for a second time. This report contains the notes for the initial version of the course. A number of changes were made in the content and emphasis of the course during its second run, mainly due to a change of personnel, with different ideas and experiences in the field of accident analysis and prevention. It is likely that each time the course is run, there will be significant changes, but that the notes provided in this document can be considered to contain a number of the core elements of any future version of the course
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