82 research outputs found

    Finite Element Analysis and Ambient Vibration Test of the Arch Type Steel Highway Bridges

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    In this paper, it is aimed to determine the dynamic characteristics of highway bridges using finite element analyses and ambient vibration tests. A modern steel highway bridge which has arch type structural system with 216 m total length and located in the Ayvacik county of Samsun, Turkey is selected as an application. Because of the fact that the bridge connects the villages which are separated with Suat Ugurlu Dam Lake, it has a major logistical importance for this region. The construction of the bridge is completed in 2009 and opened the traffic. An analytical modal analysis is performed on the developed 3D finite element model of the highway bridge to provide the analytical frequencies and mode shapes. The experimental measurements are carried out by ambient vibration tests under traffic loads. Vibration data are gathered from bridge deck. Measurement time, frequency span and effective mode number are determined by consider similar studies and literature. Enhanced Frequency Domain Decomposition method in the frequency domain and Stochastic Subspace Identification method in the time domain are used for the output only modal identification and dynamic characteristics such as natural frequencies, mode shapes and damping ratios are determined, experimentally. At the end of the study, analytically and experimentally identified dynamic characteristics are compared with each other. A good agreement is found between mode shapes, but some difference in natural frequencies

    An Anti-Cheating System for Online Interviews and Exams

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    Remote examination and job interviews have gained popularity and become indispensable because of both pandemics and the advantage of remote working circumstances. Most businesses and educational organizations use these platforms for recruitment as well as online exams. However, one of the critical problems of the remote examination systems is conducting the exams in a reliable environment. In this work, we present a cheating analysis pipeline for online interviews and exams. The system only requires a video of the candidate, which is recorded during the exam by using a webcam without a need for any extra tool. Then cheating detection pipeline is employed to detect the presence of another person, electronic device usage, and candidate absence status. The pipeline consists of face detection, face recognition, object detection, and face tracking algorithms. To evaluate the performance of the pipeline we collected a private video dataset. The video dataset includes both cheating activities and clean videos. Ultimately, our pipeline presents an efficient and fast guideline for detecting and analyzing cheating actions in an online interview and exam video

    Evaluation of epicardial adipose tissue and carotid intima-media thickness as a marker of atherosclerosis in patients with inflammatory bowel disease

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    Background and aim: this study aimed to compare carotid intima media (CIMT) and epicardial adipose tissue (EAT) measurements, which are considered as markers for the detection of early atherosclerosis in healthy controls and inflammatory bowel disease (IBD) cases. Methods: a total of 60 IBD patients (25 Crohn’s disease and 35 ulcerative colitis) and 60 healthy patients (as a control group) were included in the study. The measurements of CIMT and EAT were performed using echocardiography and ultrasonography, respectively. Statistical analysis was used to determine the relationship between the parameters. Results: the thickness of bilateral (right and left) CIMT and EAT were significantly higher in IBD than in the control group (p < 0.05). There was a positive correlation between EAT and bilateral (right and left) CIMT in IBD patients (p < 0.05)

    Subclinical atherosclerosis in Behcet's disease: A systematic review and meta-analysis.

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    OBJECTIVE: To evaluate subclinical atherosclerosis in Behcet disease (BD), we performed a systematic review and meta-analysis of studies where atherosclerosis was determined by flow-mediated dilatation (FMD) and endothelial-mediated dilatation (EMD) and by measurement of intima media thickness (IMT) of carotid arteries. METHODS: Systematic search of EMBASE and PubMed databases from January 2000 to January 2014 according to PRISMA guidelines. RESULTS: Nine studies met the inclusion criteria on FMD/EMD, 11 on IMT and 4 on both. BD had lower FMD than controls (SMD = -0.89, 95% CI: -0.660 to -1.11, p < 0.001), which was confirmed by subgroup analyses on active and inactive patients (SMD = -1.17, 95% CI: -1.45 to -0.89 and SMD = -0.72, 95% CI: -0.97 to -0.46, p = 0.0001 for both). EMD was lower in BD but with a large estimate (SMD = 0.38, 95% CI: -0.79 to -0.03, p = 0.06, I(2) = 82.2%). IMT was greater in BD and the large estimate (SMD = 0.95, 95% CI: 0.63-1.28, p < 0.0001, I(2) = 87.6%) persisted after subgroup analysis on active and inactive patients (I(2) = 88.4% and 86.7%, respectively). Pooling IMT studies by a Newcastle Ottawa Scale of 5 and 6/7 yielded lower estimates (SMD = 0.54, 95% CI: 0.32-0.75, p < 0.0001, I(2) = 58.7% and SMD = 1.72, 95% CI: 1.35-2.09 p < 0.05, I(2) = 48.6%). CONCLUSIONS: FMD is impaired in BD even in inactive state and IMT is greater despite a degree of statistical heterogeneity that reflects the clinical heterogeneity of BD. Future prospective studies should account for risk stratification of atherosclerosis in BD
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