• Journal of Welding and Joining
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• 제19권1호
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• pp.40-48
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• 2001

An ultrasonic test method, as a nondestructive test is applied to ensure the clad interface quality assessment. According to the reference codes and standards, not only korea Industrial Standard(KS) but also American Society for Testing and Materials (ASTM) Standard, ultrasonic examination procedures use the pulse-echo, A-scan, back reflection signal drop method and/or side drilled reference hole used to establish the acceptance criteria of clad material test. But the variety of bonding materials and sizes makes it difficult to produce the reference blocks, or thus the criteria. In order to overcome these practical difficulties, new ultrasonic testing criterion is suggested. In this new method, the theoretical interface reflection signal amplitude level is calculated and suggested as an acceptance criteria with the back reflection signal set to 100% FSH(Full Screen Height) which is based on acoustic impedance mismatch at the clad interface for the explosive clad ultrasonic inspection. Applicability of suggested criterion, for the explosive clad Fe-Naval Brass with different bonding quality is confirmed to the pre-existed KS and ASTM specifications and verified by using SEM (Seanning Electron Microscope) micrograph. The results obtained by the suggested method is more conservative than the results according to the KS B 0234 and ASTM A 578 specifications The suggested method could be applicable to any other combination of explosive clad ultrasonic inspection.

• 비파괴검사학회지
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• 제30권4호
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• pp.324-329
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• 2010

원자력발전소에서 사용되고 있는 연료봉은 지르코늄 합금 튜브에 동봉되어 있는 이산화우라늄 펠릿으로 구성되어 있다. 펠릿 표면은 원자로를 가동시키는 동안 국부 핫스팟을 예방하기 위해 튜브로 장전된 후 작은 구멍, 균열, 칩핑 결함이 없어야 한다. 본 논문은 X-선 단층촬영 시뮬레이션을 통하여 핵 연료봉 펠릿의 표면 결함을 검출하기 위한 타당성을 조사하였다. 병렬과 팬빔 여과후 역투영 방법을 이용하여 재구성된 영상은 시뮬레이션 데이터와 MPS(missing pellet surface) 영상데이터의 접근성을 확인하였다.

• 한국생산제조학회지
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• 제19권4호
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• pp.521-528
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• 2010

A product system will be improved continually until requirements are satisfied. It is true that considering alternative designs to improve product system is hard work; it is also true that selecting an adequate design idea that represents the needs of stakeholders concerned and meets effectiveness factors properly is not an easy work, either. In the process of driv-ing an idea and designing, which is called Design Phase, there are lots of existing tools for testing the driven idea in DFSS. But, those kinds of tools do not offer the function that helps to select the technically better design idea among alternative design ideas that have the same evaluation level. Moreover it is inappropriate to select adequate alternative design ideas by just verifying only the evaluation table in pugh matrix, since satisfied deviation val-ues are low when there is a too competitive mass product system in a market. Also, for the IT product with short life cycle, faster and more effective testing tool is needed. Therefore, the 'roduct quality index' is suggested in order to select an appropriate candidate design concept for system development that meets requirements by using 'deality concept' pro-vided by TRIZ. According to the result of this research, it is possible to select technically better idea fast and effectively; it is confirmed by applying the approach to the case of LCD BLU (Back Light Unit).

• 응용통계연구
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• 제29권4호
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• pp.753-771
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• 2016

금융기관의 위험관리를 위한 중요한 도구로서 현재 VaR가 널리 사용되고 있다. 본 논문에서는 코퓰러 함수들을 이용하여 극단치이론과 GARCH 모형을 결합한 일변량분포로부터 구축한 다변량분포들을 바탕으로 코스피, 다우존스, 상하이 그리고 니케이 지수들로 구성된 포트폴리오의 VaR 추정과 그 성과에 관해 논의하였다. 사후검증 결과 전체적으로 볼 때 가우시안, t, 클레이톤, 프랭크 코퓰러를 사용한 t-분포의 오차항을 가진 변동성 모형들이 포트폴리오 VaR의 측정에 적합한 모형들로 나타났으며, 특히 프랭크 코퓰러의 경우에 가장 우수한 성과를 나타내었다.

• 대한통합의학회지
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• 제3권4호
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• pp.53-59
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• 2015

Purpose : To retestify about the changes of the range of motion and pain from kinesiotaping the erector spinae muscle. Method : Targeted the number of 30 people with low back pain and measured lumbar range of motion and pain before kinesiotaping on the erector spinae muscle. After that, the measured value were compared and analyzed. Result : First, before and after kinesiotaping, doing skin distraction test, the changes of the skin distance within each experiment group all statistically showed meaningful differences(p<0.05). Secondly, before and after kinesiotaping and testing pain threshold, it statistically showed meaningful differences(p<0.05). Conclusion : Both two groups showed that the change of the skin distance increased and the pain averagely decreased than before taping. Therefore, kinesiotaping is considered that it affected the low back, the range of motion and pain.

• 동의생리병리학회지
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• 제21권3호
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• pp.789-793
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• 2007

To evaluate the effectiveness of cupping and bloodletting therapy in the treatment of musculoskeletal diseases. Systematic searches were conducted on KSI, KISTI, DB Pia, KIOM Database, and Koreamed until January 2007 Hand-searches included conference proceedings and our own files. There were no restrictions regarding the language of journals published in Korea. Controlled trials of dry cupping, wet cupping, or blood letting for patients with musculoskeletal disease were considered for inclusion. Trials testing other forms of dry cupping therapy were included. Methodological quality was assessed by two doctors. 20 possibly relevant studies were identified and 5 studies were included. One trial tested wet cupping for ankle sprain and reported positive result. Two trials tested blood letting for low back pain, one was positive and the other one was neutral. One trial tested the types of dry cupping for low back pain, and Ki-gong cupping therapy was superior to other two types of cupping. One trial compared wet cupping with dry cupping for low back pain and the result was negative. The effectiveness of bloodletting plus acupuncture for treating patients with low back pain is superior to acupuncture in spite of low quality. One trial of wet cupping for ankle sprain had effects in reducing pain. However, I suggest that the rigorous RCTs of cupping and blood letting therapy will be conducted in well designed features.

• The Journal of Korean Physical Therapy
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• 제31권2호
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• pp.117-121
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• 2019

Purpose: Hip rotation testing is important in the evaluation of chronic back pain. The purpose of this study was to investigate hip and lumbopelvic movement during hip medial rotation (HMR) in individuals with chronic lower back pain (CLBP). Methods: This study targeted 112 subjects in total: 28 healthy males and 28 healthy females, and 27 males with CLBP and 29 females with CLBP. Motion-capture device was used to measure the hip medial rotation angle (HMRA), lumbopelvic rotation angle (LPRA), and the rotation angle of the hip when lumbopelvic rotation starts during hip medial rotation. Results: When evaluating the healthy males and females using the hip medial rotation test (HMRT), healthy males showed a smaller HMRA than did healthy females (p<0.05). When evaluating the healthy males and the males with CLBP using the HMRT, males with CLBP showed a smaller HMRA and more lumbopelvic movements than did healthy males (p<0.05) in addition, their lumbopelvic movements occurred earlier during HMR (p<0.05). Finally, when evaluating the males and the females with CLBP using the HMRT, males with CLBP showed a smaller HMRA and more lumbopelvic movements (p<0.05), and their lumbopelvic movements occurred earlier during HMR (p<0.05). Conclusion: The HMRT is an important test for the evaluation of males, and especially males with CLBP, as they often experience an increased LPRA and decreased HMRA, with lumbopelvic movement occurring earlier during HMR when compared to other groups.

• 한국생산제조학회지
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• 제21권2호
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• pp.349-353
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• 2012

As the world wind energy market grows rapidly, the productions of wind power generation equipment have recently increased, but manufacturers are not able meet this requirement. Particularly offshore wind energy industry is one of the most popular renewable energy sectors. To generalize welding processes, the welding automation is considered for steel structure manufacturing in offshore wind energy to get high quality and productivity. Welding technology in construction of the wind towers is depended on progress productivity. In addition, the life of wind tower structures should be considered by taking account of the natural weathering and the load it endures. The root passes are typically deposited using Gas Tungsten Arc Welding(GTAW) with a specialized backing gas shield. Not only the validation consists of welders experienced in determining the welding productivity of the baseline welding procedure, but also the standard testing required by the ASME section IX and API1104 codes, toughness testing was performed on the completed field welds. This paper presents the welding characteristics of the root-pass welding of high tensile steel in manufacturing of offshore wind tower. Based on the result from welding experiments, optimal welding conditions were selected after analyzing correlation between welding parameters(peak current, background current and wire feed rate) and back-bead geometry such as back-bead width(mm) and back-bead height performing root-pass welding experiment under various conditions. Furthermore, a response surface approach has been applied to provide an algorithm to predict an optimal welding quality.

• 비파괴검사학회지
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• 제18권3호
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• pp.181-190
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• 1998

광원의 직경이 $5{\mu}m$ 수준인 X-선을 이용하여 미세 초점 X-선 단층촬영장치(computerized tomography system)를 제작하고 제어 및 계산 프로그램을 개발하였다. 본 장치는 비파괴검사용으로서 직경 20mm 이내의 시험체를 검사할 수 있다. 단층영상을 얻기 위한 계산 알고리즘으로서는 convolution back projection 알고리즘을 사용하였으며 광원의 형상을 평행 빔과 부채꼴 빔(fan beam) 등 두 종류를 사용하여 결과를 비교하였다. 장치의 제어 및 계산은 개인용 컴퓨터에서 동작하도록 하였다. 제작된 CT 장치와 프로그램을 이용하여 제작된 시편에 대하여 단층 영상을 복원하고 시편의 내부 구조 및 결함을 관찰하였다. 단층영상을 얻은 결과 실제 모습과 일치하는 재료내부의 결함에 대한 정보를 얻을 수 있었으며 해상도는 $20{\sim}30{\mu}m$정도인 것으로 판단되었다.

• 한국운동역학회지
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• 제18권1호
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• pp.117-127
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• 2008

본 연구는 개발된 태권도화에 따른 태권도 돌려차기와 몸돌려 후려차기시 기계적 마찰력과 태권도 수행력에 대하여 연구하는데 목적이 있다. 본 연구를 위하여 A.F.T.S.(Automated Footwear Testing System)과 태권도 수행력 테스트를 실시하였으며 착화감에 대한 설문을 조사하였다. 본 실험의 결과 태권도화 종류에 따라 기계적 마찰력은 유의한 차이를 보였으며, 돌려차기시 최대 자유모멘트의 통계 결과값은 p=.011 이었고, 최대 족저압에 있어서 타입 A 태권도화와 타입 B 태권도화도 사이에 있어 유의한 차이를 보였다. 착화감 설문 결과 5가지 항목에 있어 타입 A와 타입 B 태권도 사이에 있어 유의한 차이를 보였지만 타입 B와 타입 C 태권도화에 있어서는 모든 항목에서 유의한 차이를 보이지 않았다. 태권도화별 기계적 마찰력에서 유의한 차이를 보인 반면 수행력에 있어서는 영향을 미치지 못하는 것으로 판단되며, 설문 결과와 수행력 사이에 있어서도 관계가 없는 것으로 나타났다. 본 연구를 통하여 임상 실험 결과와 기계적 마찰력 정도가 태권도 수행에 영향을 주는지 여부와 훈련 시 부상 방지 및 수행력을 향상시키는 태권도화의 생체역학적 설계 및 현 개발 시제품에 대한 후속제품개발에 도움을 주고자 한다.