502 research outputs found

    Automated Surface Defect Detection using Area Scan Camera

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    This research comprises the design and fabrication of an automated surface defect detection system in which the defected part is automatically rejected. A special purpose rejection mechanism is designed in a manner to whether accept the defect free parts or reject the defected parts. The inspection vision system adopted in the design is an area scan camera, which works in conjunction with the MATLAB image acquisition tool. The control process is achieved via a PIC16F84A microcontroller, where it controls the image capturing and the defected part rejection mechanism. To validate the performance of this designed system, three types of plates were used, namely, defect free, punch defected and crack defected. Results showed that all the defected plates were rejected thus insuring the high efficiency of the system. Keywords: area scan camera, inspection vision system, surface detectio

    Utilising journey crime mapping and scripting to combat cyber ​​crime

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    Modern societies are now reliant on digital communication and networks for conducting a wide array of tasks, ranging from simple acts such as browsing the web through to mission critical tasks such as the management of critical infrastructure and industrial controls. This reliance shows a growing emphasis on strategic importance of cyberspace (Sharma, 2010). While organisations and individuals are keenly exploiting the benefits of cyberspace, these same platforms have also opened new avenues for nefarious actors in the pursuit of their criminal activities to attack, disrupt, or steal from organisations and individuals. Criminal organisations and lone criminals worldwide have access to powerful, evolving capabilities which they use to identify and target their victims allowing for the perpetration of a wide variety of cyber crimes. This paper discusses ways in which utilising methods from typically non-cyber disciplines – business and criminology – can successfully be applied to the cyber domain in order to help in the fight against and prevention of cyber crime. Through the provision of a visual representation, this paper clarifies how journey mapping and crime scripting can help in building an understanding of the steps criminals undertake during execution of a cyber crime. In essence, within our work we have deconstructed the lifecycle of a crime events and translated these into a visualisation map to show the full event process, highlighting key steps as well as positive and negative events. Such work is useful to several roles and organisation types as it can aid in their decision processes when undertaking steps in pursuit, prevention, preparation and protection

    Motion Control of an Underactuated 2-DOF Robotic Manipulator

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    This paper deals with the motion control of the end effector of a 2-DOF linkage type underactuated robotic manipulator. A simulation procedure is implemented for the motion control in which actuation and braking actions were applied on the two joints of the manipulator subsequently,  hence moving the end effector in a point to point manner through the desired path. From the results obtained, it was found that the percentage error in trajectory mainly does not exceed (1%). In some specific points on the trajectory, error reached its maximum value which was found to be (3.64%). In general, these error values are almost acceptable, although an effort will be achieved in future work to reduce this error and improve the design. Keywords: Underactuated Manipulators, Motion Control, Simulation

    Defect-unbinding transitions and inherent structures in two dimensions

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    We present a large-scale (36000-particle) computational study of the "inherent structures" (IS) associated with equilibrium, two-dimensional, one-component Lennard-Jones systems. Our results provide strong support both for the inherent-structures theory of classical fluids, and for the KTHNY theory of two-stage melting in two dimensions. This support comes from the observation of three qualitatively distinct "phases" of inherent structures: a crystal, a "hexatic glass", and a "liquid glass". We also directly observe, in the IS, analogs of the two defect-unbinding transitions (respectively, of dislocations, and disclinations) believed to mediate the two equilibrium phase transitions. Each transition shows up in the inherent structures---although the free disclinations in the "liquid glass" are embedded in a percolating network of grain boundaries. The bond-orientational correlation functions of the inherent structures show the same progressive loss of order as do the three equilibrium phases: long-range to quasi-long-range to short-range.Comment: RevTeX, 8 pages, 15 figure

    Theta Phase-dependent Modulation of Perception by Concurrent Transcranial Alternating Current Stimulation and Periodic Visual Stimulation

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    Background: Sensory perception can be modulated by the phase of neural oscillations, especially in the theta and alpha ranges. Oscillatory activity in the visual cortex can be entrained by transcranial alternating current stimulation (tACS) as well as periodic visual stimulation (i.e., flicker). Combined tACS and visual flicker stimulation modulates blood- oxygen-level-dependent (BOLD) responses and concurrent 4 Hz auditory click-trains and tACS modulates auditory perception in a phase-dependent way. Objective: In the present study, we investigated if phase synchrony between concurrent tACS and periodic visual stimulation (i.e., flicker) can modulate performance on a visual matching task. Methods: Participants completed a visual matching task on a flickering visual stimulus while receiving either in-phase (0°) or asynchronous (180°, 90°, or 270°) tACS at alpha or theta frequency. Stimulation was applied over either occipital cortex or dorsolateral prefrontal cortex (DLPFC). Results: Visual performance was significantly better during theta frequency tACS over the visual cortex when it was in-phase (0°) with visual stimulus flicker, compared to anti-phase (180°). This effect did not appear with alpha frequency flicker or with DLPFC stimulation. Furthermore, a control sham group showed no effect. There were no significant performance differences amongst the asynchronous (180°, 90°, and 270°) phase conditions. Conclusion: Extending previous studies on visual and auditory perception, our results support a crucial role of oscillatory phase in sensory perception and demonstrate a behaviourally relevant combination of visual flicker and tACS. The spatial and frequency specificity of our results have implications for research on the functional organisation of perception

    The qualification of an enrichment biomarker for clinical trials targeting early stages of Parkinson’s disease

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    As therapeutic trials target early stages of Parkinson’s disease (PD), appropriate patient selection based purely on clinical criteria poses significant challenges. Members of the Critical Path for Parkinson’s Consortium formally submitted documentation to the European Medicines Agency (EMA) supporting the use of Dopamine Transporter (DAT) neuroimaging in early PD. Regulatory documents included a comprehensive literature review, a proposed analysis plan of both observational and clinical trial data, and an assessment of biomarker reproducibility and reliability. The research plan included longitudinal analysis of the Parkinson Research Examination of CEP-1347 Trial (PRECEPT) and the Parkinson’s Progression Markers Initiative (PPMI) study to estimate the degree of enrichment achieved and impact on future trials in subjects with early motor PD. The presence of reduced striatal DAT binding based on visual reads of single photon emission tomography (SPECT) scans in early motor PD subjects was an independent predictor of faster decline in UPDRS Parts II and III as compared to subjects with scans without evidence of dopaminergic deficit (SWEDD) over 24 months. The EMA issued in 2018 a full Qualification Opinion for the use of DAT as an enrichment biomarker in PD trials targeting subjects with early motor symptoms. Exclusion of SWEDD subjects in future clinical trials targeting early motor PD subjects aims to enrich clinical trial populations with idiopathic PD patients, improve statistical power, and exclude subjects who are unlikely to progress clinically from being exposed to novel test therapeutics

    Respiratory-gated (4D) contrast-enhanced FDG PET-CT for radiotherapy planning of lower oesophageal carcinoma: Feasibility and impact on planning target volume

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    Background: To assess the feasibility and potential impact on target delineation of respiratory-gated (4D) contrast-enhanced 18 Fluorine fluorodeoxyglucose (FDG) positron emission tomography - computed tomography (PET-CT), in the treatment planning position, for a prospective cohort of patients with lower third oesophageal cancer. Methods: Fifteen patients were recruited into the study. Imaging included 4D PET-CT, 3D PET-CT, endoscopic ultrasound and planning 4D CT. Target volume delineation was performed on 4D CT, 4D CT with co-registered 3D PET and 4D PET-CT. Planning target volumes (PTV) generated with 4D CT (PTV 4DCT), 4D CT co-registered with 3D PET-CT (PTV 3DPET4DCT) and 4D PET-CT (PTV 4DPETCT ) were compared with multiple positional metrics. Results: Mean PTV 4DCT , PTV 3DPET4DCT and PTV 4DPETCT were 582.4 ± 275.1 cm 3 , 472.5 ± 193.1 cm 3 and 480.6 ± 236.9 cm 3 respectively (no significant difference). Median DICE similarity coefficients comparing PTV 4DCT with PTV 3DPET4DCT, PTV 4DCT with PTV 4DPETCT and PTV 3DPET4DCT with PTV 4DPETCT were 0.85 (range 0.65-0.9), 0.85 (range 0.69-0.9) and 0.88 (range 0.79-0.9) respectively. The median sensitivity index for overlap comparing PTV 4DCT with PTV 3DPET4DCT, PTV 4DCT with PTV 4DPETCT and PTV 3DPET4DCT with PTV 4DPETCT were 0.78 (range 0.65-0.9), 0.79 (range 0.65-0.9) and 0.89 (range 0.68-0.94) respectively. Conclusions: Planning 4D PET-CT is feasible with careful patient selection. PTV generated using 4D CT, 3D PET-CT and 4D PET-CT were of similar volume, however, overlap analysis demonstrated that approximately 20% of PTV 3DPETCT and PTV 4DPETCT are not included in PTV 4DCT , leading to under-coverage of target volume and a potential geometric miss. Additionally, differences between PTV 3DPET4DCT and PTV 4DPETCT suggest a potential benefit for 4D PET-CT. Trial registration: ClinicalTrials.gov Identifier - NCT02285660(Registered 21/10/2014)

    Measurement Bias in Caregiver-Report of Early Childhood Behavior Problems across Demographic Factors in an Echo-Wide Diverse Sample

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    BACKGROUND: Research and clinical practice rely heavily on caregiver-report measures, such as the Child Behavior Checklist 1.5-5 (CBCL/1.5-5), to gather information about early childhood behavior problems and to screen for child psychopathology. While studies have shown that demographic variables influence caregiver ratings of behavior problems, the extent to which the CBCL/1.5-5 functions equivalently at the item level across diverse samples is unknown. METHODS: Item-level data of CBCL/1.5-5 from a large sample of young children ( RESULTS: Items with the most impactful DIF across child and caregiver groupings were identified for Internalizing, Externalizing, and total Problems. The robust item sets, excluding the high DIF items, showed good reliability and high correlation with the original Internalizing and total Problems scales, with lower reliability for Externalizing. Language version of CBCL administration, education level and sex of the caregiver respondent showed the most significant impact on MI, followed by child age. Sensitivity analyses revealed that child race has a unique impact on DIF over and above socioeconomic status. CONCLUSIONS: The CBCL/1.5-5, a caregiver-report measure of early childhood behavior problems, showed bias across demographic groups. Robust item sets with less DIF can measure Internalizing and total Problems equally as well as the full item sets, with slightly lower reliability for Externalizing, and can be crosswalked to the metric of the full item set, enabling calculation of normed T scores based on more robust item sets

    Association of Atopobium vaginae, a recently described metronidazole resistant anaerobe, with bacterial vaginosis

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    BACKGROUND: Bacterial vaginosis (BV) is a polymicrobial syndrome characterized by a change in vaginal flora away from predominantly Lactobacillus species. The cause of BV is unknown, but the condition has been implicated in diverse medical outcomes. The bacterium Atopobium vaginae has been recognized only recently. It is not readily identified by commercial diagnostic kits. Its clinical significance is unknown but it has recently been isolated from a tuboovarian abcess. METHODS: Nucleotide sequencing of PCR amplified 16S rRNA gene segments, that were separated into bands within lanes on polyacrylamide gels by denaturing gradient gel electrophoresis (DGGE), was used to examine bacterial vaginal flora in 46 patients clinically described as having normal (Lactobacillus spp. predominant; Nugent score ≤ 3) and abnormal flora (Nugent score ≥ 4). These women ranged in age from 14 to 48 and 82% were African American. RESULTS: The DGGE banding patterns of normal and BV-positive patients were recognizably distinct. Those of normal patients contained 1 to 4 bands that were focused in the centre region of the gel lane, while those of BV positive patients contained bands that were not all focused in the center region of the gel lane. More detailed analysis of patterns revealed that bands identified as Atopobium vaginae were present in a majority (12/22) of BV positive patients, while corresponding bands were rare (2/24) in normal patients. (P < 0.001) Two A. vaginae isolates were cultivated from two patients whose DGGE analyses indicated the presence of this organism. Two A. vaginae 16S rRNA gene sequences were identified among the clinical isolates. The same two sequences were obtained from DGGE bands of the corresponding vaginal flora. The sequences differed by one nucleotide over the short (~300 bp) segment used for DGGE analysis and migrated to slightly different points in denaturing gradient gels. Both isolates were strict anaerobes and highly metronidazole resistant. CONCLUSION: The results suggest that A. vaginae may be an important component of the complex bacterial ecology that constitutes abnormal vaginal flora. This organism could play a role in treatment failure if further studies confirm it is consistently metronidozole resistant
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