• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.120-129
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• 2023

To evaluate the vertical loads on railway bridges, conventional load tests are typically conducted. However, these tests often entail significant costs and procedural challenges. Railway conditions involve nearly identical load profiles due to standardized rail systems, which may appear straightforward in terms of load conditions. Nevertheless, this study aims to validate load tests conducted under operational train conditions by comparing the results with those obtained from conventional load tests. Additionally, static and dynamic structural behaviors are extracted from the measurement data for evaluation. To ensure the reliability of load testing, this research demonstrates feasibility through comparisons of existing measurement data with sensor attachment locations, train speeds, responses between different rail lines, tendency analysis, selection of impact coefficients, and analysis of natural frequencies. This study applies to the Dongho Railway Bridge and verifies the applicability of the proposed method. Ten operational trains and 44 sensors were deployed on the bridge to measure deformations and deflections during load test intervals, which were then compared with theoretical values. The analysis results indicate good symmetry and overlap of loads, as well as a favorable comparison between static and dynamic load test results. The maximum measured impact coefficient (0.092) was found to be lower than the theoretical impact coefficient (0.327), and the impact influence from live loads was deemed acceptable. The measured natural frequencies approximated the theoretical values, with an average of 2.393Hz compared to the calculated value of 2.415Hz. Based on these results, this paper demonstrates that for evaluating vertical loads, it is possible to measure deformations and deflections of truss railway bridges through load tests under operational train conditions without traffic control, enabling the calculation of response factors for stress adjustments.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.3 no.1
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• pp.32-37
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• 2010

Ultrasonographic diagnosis and treatment in Orthopaedic fields had been widely used. Sonographic diagnosis and treatment of foot and ankle is convenient because of anatomical characteristics. The knowledge of the anatomy and biomechanics in foot and ankle area can help to diagnose and treat the disease around foot and ankle. 28 bone and many tendons, ligaments and muscles are consist of ankle and foot joint and the coordinative relation among these structures can allow the dual function, weight bearing and locomotion of ankle and foot during gait cycle. Foot and ankle have small room for many structures, so systemically physical examination is essential for diagnosis. Accurate understanding of foot and ankle anatomy and biomechanics could be helpful to using ultrasonograph.

• Journal of the Korean Vacuum Society
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• v.15 no.4
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• pp.338-346
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• 2006

In semiconductor process, it is so hard to predict an exact failure point of the vacuum pump due to its harsh operation conditions and nonlinear properties, which may causes many problems, such as production of inferior goods or waste of unnecessary materials. Therefore it is very urgent and serious problem to develop diagnostic models which can monitor the operation conditions appropriately and recognize the failure point exactly, indicating when to replace the vacuum pump. In this study, many influencing factors are totally considered and eventually the monitoring model using multivariate statistical methods is suggested. The pivotal algorithms are Multiway Principal Component Analysis(MPCA), Dynamic Time Warping Algorithm(DTW Algorithm), etc.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.2 s.54
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• pp.115-121
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• 2009

The paper presents a signal-based damage detection algorithm of ARX model using dynamic acceleration data. An ARX model correlates acceleration data measured at two locations in a structure by considering those two sets of data as input and output signals. For detecting damage, the error between the measured data and the predicted response from the defined ARX model is computed in time and used for a statistical evaluation. A normal distribution function from the error in time is constructed and its statistical characteristic values are used for the evaluation of damage. By comparing the normal distribution functions before and after damage, three different types of damage indices are proposed. The efficiency and limitation of the proposed algorithm with the statistical evaluation of damage indices have been examined and discussed through laboratory experiments.

• Journal of the Korean Vacuum Society
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• v.20 no.3
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• pp.165-175
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• 2011

This paper introduces statistical features observed from measured batch data from the multiple operation state variables of dry vacuum pumps running in the semiconductor processes. The amplitude distribution characteristics of such state variables as inlet pressures, supply currents of the booster and dry pumps, and exhaust pressures are shown to be divided into two or three distinctive regions. This observation gives an idea of using an adaptive parametric model (APM) chosen to describe their statistical features. This modelling, in comparison to the traditional dynamic time wrapping algorithm, is shown to provide superior performance in computation time and memory resources required in the preprocessing stage of sampled batch data for the diagnosis of running dry vacuum pumps. APM model-based batch data are demonstrated to be very appropriate for monitoring and diagnosing the running conditions of dry vacuum pumps.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.4
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• pp.779-791
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• 2021

Common web services have been continuously targeted by hackers due to an access control policy that must be allowed to an unspecified number of people. In order to cope with this situation, companies regularly check web vulnerabilities and take measures according to the risk of discovered vulnerabilities. The risk of these web vulnerabilities is calculated through preliminary statistics and self-evaluation of domestic and foreign related organizations. However, unlike static diagnosis such as security setting and source code, web vulnerability check is performed through dynamic diagnosis. Even with the same vulnerability item, various attack results can be derived, and the degree of risk may vary depending on the subject of diagnosis and the environment. In this respect, the predefined risk level may be different from that of the actual vulnerability. In this paper, to improve this point, we present a web vulnerability risk assessment model based on the attack result centering on the cyber kill chain.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.1
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• pp.103-111
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• 2021

Naju Seokdanggan, Treasure No. 49, was dismantled and reconstructed due to poor performance. During construction, the crack area was reinforced and the inclination was improved. It is necessary to analyze the stiffness changes before and after the reconstruction of these cultural properties, and to establish a database of related information. In addition, there is a need for research on a scientific non-destructive testing method capable of predicting or evaluating the reinforcing effect. In this study, a simple equation for estimating the overall stiffness of the structural system was derived from information on the elasticity coefficient and the natural frequency measured by vibration tests before and after reconstruction work, and the applicability of the equation was examined. If the stiffness of important cultural properties is regularly investigated by the suggested method, it is judged that it can be used as data to estimate the time when structural safety diagnosis is necessary or when repair or reinforcement is necessary.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.11 no.1
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• pp.12-20
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• 2008

Purpose: Chronic pulmonary disease may be caused by aspiration of gastric contents secondary to gastroesophageal reflux. At present, there is no gold standard for documenting pulmonary aspiration. The purpose of this study was to investigate the usefulness of radionuclide scintigraphy in the detection of gastroesophageal reflux and pulmonary aspiration. Methods: Thirty-five patients with suspected aspiration pneumonia, and five normal control subjects, were included in the study. All subjects underwent gastroesophageal reflux scintigraphy after the ingestion of a $^{99m}Tc$-tin colloid mixture. Dynamic images to detect gastroesophageal reflux were obtained for 1 hour. Additional static images of the chest, to detect lung aspiration, were obtained at 6 and 24 hours after oral ingestion of the tin colloid. In addition to visual analysis, pulmonary aspiration was quantitated by counting the number of pixels labeled with radioactive isotope in the region of interest (ROI) of both lung fields. Aspiration index (AI) was obtained by subtracting the pixel counts of the background from the pixel counts of the ROI. Results: Among 35 patients with suspected aspiration pneumonia, 23 proved to have gastroesophageal reflux by scintigraphy. One patient showed definite pulmonary accumulation of activity by visual analysis of the 6-hour image. Thirty of 35 (85.7%) patients showed higher AI beyond the upper limit of AI in the healthy controls. When we compared the reflux group with the non-reflux group, there was a significantly higher AI at 6 hours in the reflux group (p<0.05). Conclusion: The results suggest that radionuclide scintigraphy is useful in detecting small pulmonary aspiration in patients with suspected aspiration pneumonia secondary to reflux.

• The Korean Journal of Nuclear Medicine
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• v.25 no.2
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• pp.219-226
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• 1991

골 신티 그라피는 섬유성 골 이형성증의 초기 병소와 다골성 형 섬유성 골 이형성증의 진단에 예민한 검사 방법이나, 양성 또는 악성 골 병변과의 감별진단에 어려움이 있었다. 이에 저자들은 조직학적으로 확진된 섬유성 골 이형성증 환자 17명에서 (단골성 형 12명, 다골성 형 : 5명) $^{99m}Tc-MDP$ (20 mCi 또는 7,400 MBq) 주사후 $2\sim4$시간에 전면, 후면 전신상과 부분상을 얻은 30부위 병소를 X선 사진과 비교분석 하였으며 CT, MRI 영상과 병리조직 소견을 얻었다. 병소 침습 부위별로는 대퇴골-10예, 경골-4, 요골-2, 늑골-2, 척추골-2, 후두골-2, 장골-2, 두정골-1, 하악골-1, 접형골-1, 견갑골-1, 쇄골-1, 척골-1예 였으며 5명의 다골성 형에서는 :우 대퇴골과 우 비골 : 양측 말단 대퇴골 :좌 경골과 좌 대퇴골 :우 요골과 우 장골 양측 대퇴골, 양측 경골, 접형골, 두정골, 척추골, 늑골과 장골이었다. 골 신티 그라피 소견상 30예중 28예에서(28/30, 93.3%) 방사능 섭취 증가를 보였으며 2예에서(2/30, 6.7%)는 정상 방사능 섭취 소견을 보였으나 각각은 X선상 불투명 유리상과 골흡수 병변을 보였다. 하악골의 골 3상 스캔상 병소에 현저한 혈류 증가가 관찰되었다. X선 소견상 30예중 11예에서 (l1/30, 36.7%) 불투명 유리상의 병변을, 골 변형을 동반한 1예를 포함한 18예에서는 (18/30, 60.0%) 골흡수 병변을 보였으며, 1예의 늑골 병변은 정상소견을 보였다(1/30, 3.3%). 이상에서 골 신티 그라피 만으로 섬유성 골 이형성증을 진단하는데는 주의를 요하나 골 대사의 동적 측면인 혈류와 골 재형성 양상 특히, 초기 병변과 단골성 형 침습에서 다골성 형을 진단하는데 필수적이며 결론적으로 골 신티 그라피와 X선 촬영등은 섬유성 골 이형성증 진단에 상호보완적인 검사 방법으로 사료된다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04c
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• pp.238-240
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• 2003

게놈 프로젝트에 의해 인간 유전자 영기서열이 밝혀지면서 개개인의 유전자에 나타나는 SNP(Single Nucleotide Polymorphism)을 분석하여 질병의 진단과 예후, 치료와 예방이 미래에 가능하게 되었다. 본 논문은 그러한 SNP 분석을 위한 자동 분석 시스템의 영상 처리 과정으로서, 기존의 육안을 통해 분석하였던 TDGS 영상을 본 시스템의 자동적인 영상 처리 과정을 통해 SNP 분석을 위한 디지털 패턴을 추출한다. SNP 분석을 위해 사용되는 샘플은 대략 수백개가 되는데, 실험이라는 특성상 영상에 나타나는 불규칙한 요소들이 많고. 영상의 상태가 좋지 않은 경우 명암도가 낮은 반점들의 구분이 힘들게 된다. 본 논문에서는 TDGS 영상의 지역적 특성을 가장 잘 반영하기 위한 동적 이진화의 새로운 척도를 제안하였고, 영상에서 잡영과 배경을 제거한 후 남겨진 관심영역을 반점으로 판별하여 이를 디지털 패턴으로 추출한 결과를 보여 준다.