2,431 research outputs found

    Automatic plant pest detection and recognition using k-means clustering algorithm and correspondence filters

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    Plant pest recognition and detection is vital for food security, quality of life and a stable agricultural economy. This research demonstrates the combination of the k-means clustering algorithm and the correspondence filter to achieve pest detection and recognition. The detection of the dataset is achieved by partitioning the data space into Voronoi cells, which tends to find clusters of comparable spatial extents, thereby separating the objects (pests) from the background (pest habitat). The detection is established by extracting the variant distinctive attributes between the pest and its habitat (leaf, stem) and using the correspondence filter to identify the plant pests to obtain correlation peak values for different datasets. This work further establishes that the recognition probability from the pest image is directly proportional to the height of the output signal and inversely proportional to the viewing angles, which further confirmed that the recognition of plant pests is a function of their position and viewing angle. It is encouraging to note that the correspondence filter can achieve rotational invariance of pests up to angles of 360 degrees, which proves the effectiveness of the algorithm for the detection and recognition of plant pests

    What can the SEDs of first hydrostatic core candidates reveal about their nature?

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    The first hydrostatic core (FHSC) is the first stable object to form in simulations of star formation. This stage has yet to be observed definitively, although several candidate FHSCs have been reported. We have produced synthetic spectral energy distributions (SEDs) from 3D hydrodynamical simulations of pre-stellar cores undergoing gravitational collapse for a variety of initial conditions. Variations in the initial rotation rate, radius and mass lead to differences in the location of the SED peak and far-infrared flux. Secondly, we attempt to fit the SEDs of five FHSC candidates from the literature and five newly identified FHSC candidates located in the Serpens South molecular cloud with simulated SEDs. The most promising FHSC candidates are fitted by a limited number of model SEDs with consistent properties, which suggests the SED can be useful for placing constraints on the age and rotation rate of the source. The sources we consider most likely to be in FHSC phase are B1-bN, CB17-MMS, Aqu-MM1 and Serpens South candidate K242. We were unable to fit SerpS-MM22, Per-Bolo 58 and Chamaeleon-MMS1 with reasonable parameters, which indicates that they are likely to be more evolved.Comment: 26 pages, 28 figures. Accepted for publication in MNRA

    Illumination invariant stationary object detection

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    A real-time system for the detection and tracking of moving objects that becomes stationary in a restricted zone. A new pixel classification method based on the segmentation history image is used to identify stationary objects in the scene. These objects are then tracked using a novel adaptive edge orientation-based tracking method. Experimental results have shown that the tracking technique gives more than a 95% detection success rate, even if objects are partially occluded. The tracking results, together with the historic edge maps, are analysed to remove objects that are no longer stationary or are falsely identified as foreground regions because of sudden changes in the illumination conditions. The technique has been tested on over 7 h of video recorded at different locations and time of day, both outdoors and indoors. The results obtained are compared with other available state-of-the-art methods

    Survey of European Green Crabs and Asian Shore Crabs in Salem Sound

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    The European green crab (Carcinus maenas) has been the dominant crab species in New England rocky intertidal zones since the late 1800’s, but since around 2000 they have begun to be outcompeted by a new invasive species, the Asian shore crab (Hemigrapsus sanguineus). Rocky intertidal zones at Chandler Hovey Park in Marblehead, MA and Pavilion Beach in Ipswich, MA were surveyed for both species monthly at low tide from June 2019 through March 2020. Asian shore crabs made up 94% of all crabs surveyed compared to European green crabs (6%). Also, at both sites, the average carapace width of European green crabs was found to be larger than that of the Asian shore crabs collected. From this survey, it appears that Asian shore crabs are outcompeting European green crabs at these locations

    A systematic review evaluating the implementation of technologies to assess, monitor and treat neurodevelopmental disorders: A map of the current evidence

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    Technology-based interventions provide an attractive option for improving service provision for neurodevelopmental disorders (NDD), for example, widening access to interventions, objective assessment, and monitoring; however, it is unclear whether there is sufficient evidence to support their use in clinical settings. This review provides an evidence map describing how technology is implemented in the assessment/diagnosis and monitoring/ treatment of NDD (Prospero CRD42018091156). Using predefined search terms in six databases, 7982 articles were identified, 808 full-texts were screened, resulting in 47 included papers. These studies were appraised and synthesised according to the following outcomes of interest: effectiveness (clinical effectiveness/ service delivery efficiencies), economic impact, and user impact (acceptability/ feasibility). The findings describe how technology is currently being utilised clinically, highlights gaps in knowledge, and discusses future research needs. Technology has been used to facilitate assessment and treatment across multiple NDD, especially Autism Spectrum (ASD) and attention-deficit/hyperactivity (ADHD) disorders. Technologies include mobile apps/tablets, robots, gaming, computerised tests, videos, and virtual reality. The outcomes presented largely focus on the clinical effectiveness of the technology, with approximately half the papers demonstrating some degree of effectiveness, however, the methodological quality of many studies is limited. Further research should focus on randomised controlled trial designs with longer follow-up periods, incorporating an economic evaluation, as well as qualitative studies including process evaluations and user impact
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