• 대한방사선기술학회지:방사선기술과학
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• 제15권2호
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• pp.49-66
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• 1992

• 대한방사선과학회:학술대회논문집
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• 대한방사선과학회 1992년도 학술대회
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• pp.17-19
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• 1992

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.70-72
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• 2007

In this study, electromagnetic fields emitted from the various environment in the hospital were measured. Measurement spot was patients' head. To monitor how much magnetic fields are emitting from operation room, monitoring device was attached to 19 anesthesiologist and monitoring lasted 8 hours. We also took a measurement from various medical devices. Devices include ESWL, PET, MRI, CT, Gamma knife, X-ray, Angiogram, Echocardiogram, Upper GI and Linear Accelerator. Electromagnetic fields were measured from 10 spots from each of 5 patient waiting room. As a results, there were no places showing risk of high exposure. All the measurement values were below the reference levels for general public exposure to time varying electric and magnetic fields which is issued by ICNIRP.

• 대한의용생체공학회:의공학회지
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• 제26권4호
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• pp.251-255
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• 2005

When the extracorporeal shock wave lithotriptor is operated, sounds can be heard. Then that might be a question about the location where the sounds come from. For the purpose of investigating the fact, we identify the location of the sounds radiated using one hydrophone. In order to carry out the experiment, it is needed to obtain direct waves from objects. Therefore, we present an experimental method to reduce reflected waves for obtaining direct waves only. The experimental results show the amplitude of waves can be attenuated about 28dB due to a silicon rubber plate of 8.5mm attached at the bottom. This is a quantified result that can expect to obtain the direct waves using the proposed method. Then, we carried out the experiment for the sound source location. From the experimental results, we can undoubtedly present a fact that the sounds are radiated from the objects to be shot due to shock waves.

• 대한방사선기술학회지:방사선기술과학
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• 제28권4호
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• pp.287-291
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• 2005

완전 폐색을 동반한 상부 요관 결석의 크기에 따른 치료 방법의 적절한 시기를 결정하기 위해 2002년 1월부터 2004년 8월까지 Dornier사의 MPL 9000 체외충격파쇄석기에 의해 치료 받은 201명을 대상으로 하였다. 전체 대상 201명 중, 완전 폐색을 동반하지 않은 경우는 142명이었으며, 완전 폐색을 동반한 경우는 59명이었다. 완전 폐색을 동반하지 않은 경우의 체외충격파쇄석술의 1회, 2회, 3회 누적 성공률은 각각 68.3%, 86.6%, 94.4%이었으며, 결석 크기 10 mm 미만, 10 mm에서 20 mm 미만, 20 mm 이상의 3회 누적 성공률은 각각 100%, 90.5%, 00.0%이었다. 완전 폐색을 동반한 경우의 체외충격파쇄석술의 1회, 2회, 3회 누적 성공률은 각각 44.1%, 66.1%, 76.3%이었으며, 결석 크기 10 mm 미만, 10 mm에서 20 mm 미만, 20 mm 이상의 3회 누적 성공률은 각각 완전 폐색을 동반한 경우는 각각 100%, 65.5%, 33.3%이었다. 완전 폐색을 동반한 상부 요관 결석의 크기는 체외충격파쇄석술에 의미 있는 영향을 주었다. 저자 등은 상부 요관 결석의 치료 방법 선택에 있어서, 완전 폐색을 동반하면서 그 크기가 10 mm 이상인 결석에 대해서는 체외충격파쇄석술 보다는 요관경하배석술 등 다른 방법을 일차적으로 선택할 것을 제안한다.

• 대한방사선기술학회지:방사선기술과학
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• 제22권1호
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• pp.87-90
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• 1999

Treatment of human calculi by extracorporeal shock-wave lithotripsy(ESWL) was introduced for kidney stones in 1980. This technology was then applied to the treatment of bile duct stones and pancreatic stones. Some reports have also shown that disintegration of pancreatic stones by extracorporeal shock-wave lithotripsy is possible with successful subsequent endoscopic extraction of the fragments at home ana abroad. We tried removal of pancreatic calcification stones by endoscopic procedures, but could't be removed because the basket got entagled in the endoscopy. We report one case of this pancreatic calcification stones ; the stones were successfully fragmented and completely removal by extracorporeal shock-wave lithotripsy.

• 한국음향학회지
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• 제19권5호
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• pp.35-40
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• 2000

본 연구에서는 먼저 압전형 쇄석기에 의한 충격파 조사시에 발생하는 파쇄대상물의 진동과 그 때 들려오는 방사음과의 관계에 대하여 검토한다. 다음에 대상물에 있어서의 초점위치와 고유진동과의 관계에 대해서도 조사한 결과를 제시한다. 아울러 동일한 실험을 파쇄가능한 대상물에 시행하여 대상물의 진동과 그 파쇄효율과의 관계에 대해서도 실험적으로 검토한다. 그 결과, 초점위치에 따른 대상물 고유진동의 피크 주파수 파워와 파쇄효율과의 상관성을 명확히 확인할 수 있었다.

• 한국음향학회지
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• 제25권1호
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• pp.43-48
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• 2006

압전식 충격파 쇄석기를 사용하여 대상물을 파쇄하는 과정에서 발생하는 음의 특성을 조사한 결과, 대상물이 파쇄됨에 따라 방사음이 더욱 저주파대로 이동한다는 실험적인 결과가 발표되었고(2), 이 결과를 입증하기 위하여 실제의 대상물이 파쇄되어가는 과정을 모델링하여 제작한 대상물을 사용한 실험에서도 동일한 결과가 관측되었다. 본 논문에서는 이와 같이 실험적으로 밝혀진 연구결과를 이론적으로 확인하고자 한다. 따라서, 유한요소법을 이용한 수치 시뮬레이션을 실험과 유사하게 모델링한 대상물에 실행하였고, 시뮬레이션에서 관측된 결과를 제시하여 실험적으로 관측된 결과가 이론적으로도 유효하다는 것을 입증하였다.

• Steel and Composite Structures
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• 제24권2호
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• pp.227-237
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• 2017

This paper presents optimization of a long-span portal steel frame under dynamic wind loads using a surrogate-assisted evolutionary algorithm. Long-span portal steel frames are often used in low-rise industrial and commercial buildings. The structure needs be able to resist the wind loads, and at the same time it should be as light as possible in order to be cost-effective. In this work, numerical model of a portal steel frame is constructed using structural analysis program (SAP2000), with the web-heights at five locations of I-sections of the columns and rafters as the decision variables. In order to evaluate the performance of a given design under dynamic wind loading, the equivalent static wind load (ESWL) is obtained from a database of wind pressures measured in wind tunnel tests. A modified formulation of the problem compared to the one available in the literature is also presented, considering additional design constraints for practicality. Evolutionary algorithms (EA) are often used to solve such non-linear, black-box problems, but when each design evaluation is computationally expensive (e.g., in this case a SAP2000 simulation), the time taken for optimization using EAs becomes untenable. To overcome this challenge, we employ a surrogate-assisted evolutionary algorithm (SAEA) to expedite the convergence towards the optimum design. The presented SAEA uses multiple spatially distributed surrogate models to approximate the simulations more accurately in lieu of commonly used single global surrogate models. Through rigorous numerical experiments, improvements in results and time savings obtained using SAEA over EA are demonstrated.

• 대한방사선기술학회지:방사선기술과학
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• 제16권1호
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• pp.89-94
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• 1993

However, technical advances in ultrasono imaging have had a remarkable impact on the study of biliary system oral cholecystography is a contrast of the gallbladder which is very frequently performed even with the application of Extra Shock Wave Lithotripsy(ESWL) in clinical use. Oral GB requires a stringent preparation if it is to be fully successful and a considerable amount of time to complete all its procedures and its objects of the radiographs. 1) to obtain a firm diagnosis of the presence of gallstones. 2) to essess function of the gallbladder that is, its ability to concentrate and store bile. After a times sequence of X-ray exposures taken in various positions to show the gallbladder to be satisfactorily filled, the patient is given a fatty meal, for instances two eggs or a cup of milk. The gallbladder which is drained by the cystic duct stores and concentrates the bile and is stimulated to contrast and excrete the bile by hormone "cholecystokinin" secreted in the intestinal mucosa. To evaluate the effect of the fatty meal which caused the gallbladder to constrict and empty, and by so doing the contrast medium passes through the cystic and bile ducts which are shown in radiographs exposed from 15-30 minutes after the variety practice of fattymeal, such as soft-boiled 2 eggs, raw 2 eggs, 100g of peanuts, and 200ml of milk. If the concentration of the opaque medium in the gallbladder is adequate, then not only the size, shape and position of the gallbladder will be shown from firms taken at intervals, the rate of concentration of the opaque medium and of the emptying of gallbladder has been measured and analyzed.