5,480 research outputs found

    Image segmentation evaluation using an integrated framework

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    In this paper we present a general framework we have developed for running and evaluating automatic image and video segmentation algorithms. This framework was designed to allow effortless integration of existing and forthcoming image segmentation algorithms, and allows researchers to focus more on the development and evaluation of segmentation methods, relying on the framework for encoding/decoding and visualization. We then utilize this framework to automatically evaluate four distinct segmentation algorithms, and present and discuss the results and statistical findings of the experiment

    A framework and user interface for automatic region based segmentation algorithms

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    In this paper we describe a framework and tool developed for running and evaluating automatic region based segmentation algorithms. The tool was designed to allow simple integration of existing and future segmentation algorithms, both single image based algorithms and those that operate on video data. Our framework supports plug-in segmenters, media decoders, and region-map codecs. We provide several sophisticated implementations of these plug-ins, including a video decoder capable of frame accurate decoding of a large variety of video formats, an image decoder which also handles a comprehensive collection of formats, and a efficient implementation of a region-map codec. The tool includes both a graphical user interface to allow users to browse, visually inspect, and evaluate the algorithm output, and a batch processing interface for segmentation of large data collections. The application allows researchers to focus more on the development and evaluation of segmentation methods, relying on the framework for encoding/decoding input and output, and the front end for visualization

    Effects of Simulated Grazing on Fire-Treated Mine Tailings for Restoration

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    The alterations caused to the landscape while mining operations extract necessary materials are unavoidable but not completely permanent changes. Through dedication to the communities they border, mining companies have progressed the science of reclamation and are beginning to restore once wild places to more natural looking environments. In the early days of reclamation, aggressive agronomic vegetative species were used to establish vegetation cover to prevent erosion and act as the framework for eventual succession to a more natural pre-disturbed state. In practice on some sites, these agronomic species are becoming monocultures which are utilized by small mammals and ungulates but are not being displaced by planted native grasses to fully reclaim an area to its natural form. The use of prescribed burning to bring disturbance to a landscape and provide space for native grasses has had some positive results but more might be done to help these grasses become established more permanently. Herbicide works to reduce competition for nutrients and water uptake but without removing the dead material the leftover litter layer would still prevent small native grasses from obtaining light. I intend to look at the possibility of using simulated cattle grazing as a means of added disturbance to provide space for seeded native species to grow and eventually lead to early successional change to re-establish a pre-disturbed natural state on a dry tailing storage facility

    Association between body mass index and mental health among Scottish adult population: a cross-sectional study of 37,272 participants

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    <b>Background:</b> The evidence is conflicting as to whether body mass index (BMI) is associated with mental health and, if so, to what extent it varies by sex and age. We studied mental health across the full spectrum of BMI among the general population, and conducted subgroup analyses by sex and age.<p></p> <b>Method:</b> We undertook a cross-sectional study of a representative sample of the Scottish adult population. The Scottish Health Survey provided data on mental health, measured by the General Health Questionnaire-12 (GHQ), BMI, demographic and life-style information. Good mental health was defined as a GHQ score <4, and poor mental health as a GHQ score ā‰„4. Logistic regression models were applied. Results Of the 37 272 participants, 5739 (15.4%) had poor mental health. Overall, overweight participants had better mental health than the normal-weight group [adjusted odds ratio (OR) 0.93, 95% confidence interval (CI) 0.87ā€“0.99, p = 0.049], and individuals who were underweight, class II or class III obese had poorer mental health (class III obese group: adjusted OR 1.26, 95% CI 1.05ā€“1.51, p = 0.013). There were significant interactions of BMI with sex (p = 0.013) and with age (p < 0.001). Being overweight was associated with significantly better mental health in middle-aged men only. In contrast, being underweight at all ages or obese at a young age was associated with significantly poorer mental health in women only.<p></p> <b>Conclusions:</b> The adverse associations between adiposity and mental health are specific to women. Underweight women and young women who are obese have poorer mental health. In contrast, middle-aged overweight men have better mental health.<p></p&gt

    Mapping Lyman Continuum escape in Tololo 1247-232

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    Low redshift, spatially resolved Lyman continuum (LyC) emitters allow us to clarify the processes for LyC escape from these starburst galaxies. We use Hubble Space Telescope (HST) WFC3 and ACS imaging of the confirmed low-redshift LyC emitter Tol 1247-232 to study the ionization structure of the gas and its relation to the ionizing star clusters. We perform ionization parameter mapping (IPM) using [O III]4959, 5007 and [O II]3727 imaging as the high- and low-ionization tracers, revealing broad, large-scale, optically thin regions originating from the center, and reaching the outskirts of the galaxy, consistent with LyC escape. We carry out stellar population synthesis modeling of the 26 brightest clusters using our HST photometry. Combining these data with the nebular photometry, we find a global LyC escape fraction of f_esc = 0.12, with uncertainties also consistent with zero escape and with all measured f_esc values for this galaxy. Our analysis suggests that, similar to other candidate LyC emitters, a two-stage starburst has taken place in this galaxy, with a 12 Myr old, massive, central cluster likely having pre-cleared regions in and around the center, and the second generation of 2 - 4 Myr old clusters dominating the current ionization, including some escape from the galaxy.Comment: Accepted for publication in Ap

    Biomechanical testing of hip protectors following the Canadian Standards Association express document

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    Summary A variety of hip protectors are available, but it is not clear which is the most effective and there is no standard test to evaluate their performance. This is the first study that uses a standard mechanical test on hip protectors. Some protectors perform well but others are almost ineffective, providing little to no protection to the wearer during a fall. Introduction Each year, over 70,000 patients are admitted to hospital in the UK with hip fractures. There are a variety of commercial hip protectors currently available. However, it is not explicitly clear which is the most effective with regard to maximum force attenuation, whilst still being both comfortable for the user and providing reasonable force reduction if misplaced from the intended position. The numerous test methods reported in the literature have given conflicting results, making objective comparison difficult for users, researchers, and manufacturers alike. The Canadian Standards Association (CSA) has therefore published an express document (EXP-08-17) with a draft standard test method. This paper presents initial results for a range of hip protectors. Methods Eighteen commercially available hip protectors were tested according to EXP-08-17. Each hip protector was impacted five times in correct anatomical alignment over the greater trochanter and once at 50 mm displacements in the anterior, posterior, and lateral directions. Results Considerable differences were identified between individual hip protectors in their ability to reduce impact forces on the femur (between 3% and 36% reduction in peak force). The performance was reduced when misplaced in many cases (maximum reduction only 20%). Conclusions This is the first study that uses a standard mechanical test on hip protectors. Previous studies have used a variety of methods, making it difficult to interpret results. We hope that these results using a standard test method will facilitate the effective comparison of results, as well as providing useful data for clinicians, users, and purchasers
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