10 research outputs found

    Improving Detection of Dim Targets: Optimization of a Moment-based Detection Algorithm

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    Wide area motion imagery (WAMI) sensor technology is advancing rapidly. Increases in frame rates and detector array sizes have led to a dramatic increase in the volume of data that can be acquired. Without a corresponding increase in analytical manpower, much of these data remain underutilized. This creates a need for fast, automated, and robust methods for detecting dim, moving signals of interest. Current approaches fall into two categories: detect-before-track (DBT) and track-before-detect (TBD) methods. The DBT methods use thresholding to reduce the quantity of data to be processed, making real time implementation practical but at the cost of the ability to detect low signal to noise ratio (SNR) targets without acceptance of a high false alarm rate. TBD methods exploit both the temporal and spatial information simultaneously to make detection of low SNR targets possible, but at the cost of computation time. This research seeks to contribute to the near real time detection of low SNR, unresolved moving targets through an extension of earlier work on higher order moments anomaly detection, a method that exploits both spatial and temporal information but is still computationally efficient and massively parallellizable. The MBD algorithm was found to detect targets comparably with leading TBD methods in 1000th the time

    Early age delamination in concrete pavements made with gravel aggregates

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    Gravel aggregates had been used extensively in the Houston District of Texas Department of Transportation (TxDOT) for continuously reinforced concrete pavements construction for many years. However, some of these pavements have been subject to early age delamination and eventual spalling damage. Therefore, a series of studies funded by TxDOT since the early 1990's has been conducted to gain a better understanding of mechanisms, material properties, and construction practices, and to provide guidelines and recommendations for minimizing early-age delamination in concrete pavements made with gravel aggregates. In this study, a test protocol to measure the bond strength between aggregates and cement mortar was established, and the effects of different material and construction parameters on the bond strength of concrete at early ages using a fractional factorial design were investigated. The significances of each factor to achieve better bonding performance were determined, and the optimum design combination was subsequently chosen and validated. Geometric parameters were proposed to characterize aggregate shape properties relative to bonding performance with the facilitation of the Aggregate Imaging System. A rating system based on utility theory was developed to evaluate the overall contribution of aggregate properties (i.e. physical, geometric, and chemical) to the concrete bonding capability and the feasibility of certain mixture design combinations. As for theoretical representation of the bond strength across the interfacial transition zone, a model of interfacial fracture energy between aggregate and mortar that represents the energy necessary to create a crack along the interface was formulated. This model built the connection between concrete properties at the meso-level (represented by the interfacial fracture energy between aggregate and mortar) and the macro-level (represented by fracture toughness of concrete and significant influencing materials and construction factors). In addition, the moisture effects on stress development of concrete pavements at early ages using field data as inputs were numerically simulated, and a fracture mechanics-based approach was used to predict the occurrence of delamination. A delamination detection protocol for the field was developed to explore the feasibility and potential of utilizing Ground Penetration Radar technology in delamination detection. Research findings from laboratory investigation, field testing, theoretical modeling, and numerical analysis were further validated through field test sections, and the associated framework for delamination guidelines was established

    Shortest Route at Dynamic Location with Node Combination-Dijkstra Algorithm

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    Abstract— Online transportation has become a basic requirement of the general public in support of all activities to go to work, school or vacation to the sights. Public transportation services compete to provide the best service so that consumers feel comfortable using the services offered, so that all activities are noticed, one of them is the search for the shortest route in picking the buyer or delivering to the destination. Node Combination method can minimize memory usage and this methode is more optimal when compared to A* and Ant Colony in the shortest route search like Dijkstra algorithm, but can’t store the history node that has been passed. Therefore, using node combination algorithm is very good in searching the shortest distance is not the shortest route. This paper is structured to modify the node combination algorithm to solve the problem of finding the shortest route at the dynamic location obtained from the transport fleet by displaying the nodes that have the shortest distance and will be implemented in the geographic information system in the form of map to facilitate the use of the system. Keywords— Shortest Path, Algorithm Dijkstra, Node Combination, Dynamic Location (key words

    A Systematic Review and Meta-Analysis of the Incidence of Injury in Professional Female Soccer

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    The epidemiology of injury in male professional football is well documented and has been used as a basis to monitor injury trends and implement injury prevention strategies. There are no systematic reviews that have investigated injury incidence in women’s professional football. Therefore, the extent of injury burden in women’s professional football remains unknown. PURPOSE: The primary aim of this study was to calculate an overall incidence rate of injury in senior female professional soccer. The secondary aims were to provide an incidence rate for training and match play. METHODS: PubMed, Discover, EBSCO, Embase and ScienceDirect electronic databases were searched from inception to September 2018. Two reviewers independently assessed study quality using the Strengthening the Reporting of Observational Studies in Epidemiology statement using a 22-item STROBE checklist. Seven prospective studies (n=1137 professional players) were combined in a pooled analysis of injury incidence using a mixed effects model. Heterogeneity was evaluated using the Cochrane Q statistic and I2. RESULTS: The epidemiological incidence proportion over one season was 0.62 (95% CI 0.59 - 0.64). Mean total incidence of injury was 3.15 (95% CI 1.54 - 4.75) injuries per 1000 hours. The mean incidence of injury during match play was 10.72 (95% CI 9.11 - 12.33) and during training was 2.21 (95% CI 0.96 - 3.45). Data analysis found a significant level of heterogeneity (total Incidence, X2 = 16.57 P < 0.05; I2 = 63.8%) and during subsequent sub group analyses in those studies reviewed (match incidence, X2 = 76.4 (d.f. = 7), P <0.05; I2 = 90.8%, training incidence, X2 = 16.97 (d.f. = 7), P < 0.05; I2 = 58.8%). Appraisal of the study methodologies revealed inconsistency in the use of injury terminology, data collection procedures and calculation of exposure by researchers. Such inconsistencies likely contribute to the large variance in the incidence and prevalence of injury reported. CONCLUSIONS: The estimated risk of sustaining at least one injury over one football season is 62%. Continued reporting of heterogeneous results in population samples limits meaningful comparison of studies. Standardising the criteria used to attribute injury and activity coupled with more accurate methods of calculating exposure will overcome such limitations
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