• 한국의학물리학회지:의학물리
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• 제8권1호
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• pp.37-45
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• 1997

차폐된 질 원주기구를 이용한 강내치료시 Co-60 선원에 대한 정확한 흡수선량을 결정 하고자 선원을 교정하고, 질 원주기구에 의한 선량분포변화를 조사하였다. 선량분포의 변화량은 직경 2.5 cm 차폐된 질 원주기구를 폴리스틸렌 팬톰에 설치하여 전리함으로 측정하였으며, 부채꼴 모양인 0.55cm 두께의 9$0^{\circ}C$ 연으로 차폐된 면과 차폐되지 않은 면의 선량분포에 대한 영향을 상대선량 감소율로 측정하였다. 측정된 선량분포의 변화량을 제작사의 선량분포도 및 다점 분할방식으로 구한 선량율표와 비교하였다. 질 원주기구를 이용한 선량 감소율은 차폐되지 않은 변의 경우 원주기구 표면 1cm 거리에서 4.4%를 보였고, 차폐된 면에서는 원주기구 표면에서 20.4% 를 나타냈다. 9$0^{\circ}C$연 차폐된 질 원주기구의 선량감쇄효율은 Co-60 선원에서 평균 0.2가 되었다. Co-60 이동형 선원의 선량분포는 다 점분할방식의 선량율표와 4.1% 이내로 일치하였다.

• The Journal of Korean Physical Therapy
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• 제14권1호
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• pp.75-88
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• 2002

The purpose of this study was to investigate the influence of anterior, posterior, and lateral pelvic tilt exercise upon the gait characteristics of patients with hemiplegia including their gait velocity, cadence, stride length, step length of the non affected side, step length of the affected side, foot angle of the non affected side, foot angle of the affected side, base of support, and so on. The subject of this study was 24 men and women patients with hemiplegia. The patients, the subject of this study, were classified into 12 patients of treatment group applying pelvic tilt exercise using visual feedback and 12 patients of control group applying general pelvic tilt exercise, and then analyzed their gait before and after exercise. Temporal distance gait analysis (Boening, 1977) was used to analyze their gait, and ink foot-print was applied as on of measurement methods. To find out meaningful difference between control group and treatment group, this study carried out independent sample t-test for each item by utilizing SPSS/Win 10.0, compared changes in control group's and treatment group's gait characteristics before and after exercise as percentage, and applied paired t-test to conduct before-after test in same group. Statistical significance level was ${\alpha}$ < 0.05. The results of this study were as follows. As a result of independent sample t-test for control group's and treatment group's gait characteristics after exercise, it was not statistically significant so there was no meaningful difference between two groups. However, it was statistically significant in the change rate(%) of gait characteristics, and treatment group's patients with hemiplegia had been highly changed in gait characteristics in comparison with control group. From the above-mentioned results, could find that pelvic tilt exercise using visual feedback for patients with hemiplegia was effective to improve their gait ability and it could increase the ability in comparison with general pelvic tilt exercise. In the future, studies on the effect of pelvic tilt exercise using visual feedback shall be continued based on more quantitative methods.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.515-518
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• 2007

SAFRS(Spontaneous Acoustic Field Reproduction System) is a system to sense changes of surroundings and produce sounds which can go well with environment elements sensed by the system in to the space. The sounds were judged by individual evaluation and, the classification of the preferred sounds according to the mood of the space was suggested in the former study. Effectiveness of SAFRS with field application was validated by prior studies which dealt with researching acoustic environment, evaluating images of sounds, and rating environment with existence and nonexistence of sound resources such as fountains and the system after applied in D university. In this study, for more effective field application of SAFRS, research for the acoustic environment around sound resources and subjective evaluation of the preference of the sounds from the resources were made and it was considered that the results of the experiments should be primary information to propose proper sound level to be offered by the system. The results of the study are as follows; 1) It was considered that the ambience of the center road was dependent upon produced sounds by the system and water sounds of the fountain and that of walk way was mostly dependent upon produced sounds. 2) The results of the subjective evaluation showed that the distance from sound resources was suggestive; the more distant from produced sounds the less full and clear the sounds, the less distant from the sounds of water the more delight and idyllic ambience, and the less distant from the forest the more idyllic ambient and diversity. 3) The results upwards were telling that an average value of six elements for the evaluation was even at the place set back 10.2m from center road and walk way. And harmony of all sounds of the place should be considered to propose suitable sound level of SAFRS.

• 암석학회지
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• 제23권2호
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• pp.119-138
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• 2014

활화산을 감시하는 방법은 육안으로 직접 관찰하는 방법, 과거의 분화 기록 문건을 참조하는 방법, 직접적으로 관측 장비를 동원하여 화산체를 감시하는 방법 등이 있다. 이 중 관측 장비를 이용하여 화산체를 감시하는 방법 중 가장 기본적인 것은 지진활동도의 감시이며, 이외에도 지진계에 기록된 지진활동 중 인위적인 노이즈를 걸러내는 데 효과적인 공진 관측, 그리고 정밀수준기, 전자거리측정기, 경사계, GPS, InSAR 관측법을 통한 지표변형의 감시, 화산가스 감시, 수문학적/기상학적 감시, 기타 지구물리학적 감시 등의 방법이 있다. 이러한 감시 기법을 통해 화산의 활동을 효과적으로 감시하고 이를 통해 지하 마그마방에서의 마그마 거동을 파악함으로써 미래의 화산 분화를 보다 정확하게 예측하고 조기 경보하여 그에 따른 재해의 피해를 경감하고 최소화 할 수 있다.

• 대한전자공학회논문지
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• 제26권7호
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• pp.166-175
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• 1989

본 논문은 rotation of subspaces 개념을 이용한 도래각 추정 방법을 제시한다. 이 방법은 여러 응용분야에서 대두되는 부공간들(subspaces)의 각도 및 거리와 밀접한 관련이 있다. 먼저 최소 자승을 이용하여 한 부공간을 다른 부공간으로 변환 시켜주는 최적 변환 행렬을 구하기 위한 효율적인 방법을 유도하고 이를 이용하여 다중 광대역 신호들 (인코히어런트, 부분적인 코히어런트와 완전한 코히어런트의 혼합신호들)의 도래각을 추정한다. 대표적인 응용으로, 잡음의 배열 스펙트럼 밀도 행렬이 변하지 않는 액티브 시스템(e. g. sonar system) 경우에 성능을 높이기 위하여 효율적인 ROSS (rotation of signal subspaces) 알고리듬을 제안한다. ROSS 알고리듬은 Wang-Kaveh's CSS-focusing 방법에서 사용하는 예비처리와 공간 필터링을 필요로 하지 않는 장점이 있으며 일반적인 모든 배열 안테나에도 적용될 수 있다. 시뮬레이션 결과, 제안된 새로운 알고리듬이 CSS-focusing 방법 및 Forward-Backward Spatial Smoothed MUSIC 보다 높은 성능을 가짐을 알 수 있었다.

• 정보교육학회논문지
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• 제17권1호
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• pp.23-31
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• 2013

초등학생들이 쉽게 스마트폰을 접근할 수 있고 또한 흥미를 가질 수 있다. 스마트폰을 초등학교 학습 도구로 이용하여 학습 효과를 볼 수 있을 것이다. 따라서 스마트폰을 과학 실험의 학습 도구에 이용하면 학습 효과가 좋을 것이다. 속력 학습 분야가 초등학생들이 학습하기 어려운 개념이기 때문에 스마트폰 용 속력 학습 어플리케이션으로 많은 실험을 해 보는 것이 필요하다. 본 연구에서 속력 학습을 위한 모듈을 개발한다. 이 모듈은 스마트폰의 가속도 센서에서 데이터를 추출하고, 주어진 시간에 적분하여 속력을 계산한다. 또한 거리도 계산한다. 본 연구에서 제안한 어플리케이션은 학생들이 실험 시 속력 변화를 즉시 확인할 수 있도록 하는 장점이 있다. 본 연구의 장점은 기존의 속력 측정 도구는 실험과 측정 데이터 값이 분리되어 있어 학생들이 재차 속력을 계산해야 하는 번거로움을 극복한 것이다.

• Journal of Biosystems Engineering
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• 제40권1호
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• pp.19-27
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• 2015

Purpose: A system to measure the visibility of agricultural tractor operators was designed and evaluated according to ISO standards, and a blind area diagram around the tested tractor was created based on the manual method recommended by the National Institute for Occupational Safety and Health (NIOSH). Methods: A visibility measurement system was designed and evaluated based on the ISO 5006 and ISO 5721-1 standards. Two bulbs used to simulate the operator's eyes were mounted on a bar with a supporting frame. A wooden frame was used to determine the seat index point position. The 12-m visibility test circle was divided into six sectors of vision, and the test tractor was placed at the center of the circle. Artificial light was supplied in the darkened environment, and shadow or masking effects were measured manually around the 12-m circle. Results: When the bulbs were placed at the operator's eye level, front visibility was good; no masking was found in the "A" vision sector, but larger masking widths were found in the "B" and "C" vision sectors. Since the masking width exceeded 700 mm, additional tests, such as movement of the light sources to both sides of the operator's eye level, were performed. Less than six masking effects were found in the semi-circle of vision to the front, and more than one masking was found in the "B" and "C" visual fields. The minimum distance between the centers of two masking effects exceeded 2500 mm when measured as a chord on the semi-circle of vision. A blind area diagram was created to define the exact nature of the blind spots and mirror visibility. Conclusions: Visibility evaluation is an effective way to enable proper and safe operation for agricultural tractor operators. Inclusion of this visibility evaluation test in the general testing process might aid tractor manufacturers.

• 한국소음진동공학회논문집
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• 제24권12호
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• pp.969-976
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• 2014

Nowadays, it is required for naval ships to estimate 3D underwater radiated noise pattern in all direction at peak frequencies of hull vibration for the reduction of being detected and doing the effective operation. For this purpose, the numerical method has to be developed to calculate 3D underwater radiated noise pattern with experimental data. It is very difficult to obtain the experimental data for the real ship. Alternative to get the experimental results is to use NAH(near-field acoustic holography) in acoustic tank with experimental model. Application of NAH in acoustic tank for the experimental model needs some investigation of reflection wave from the wall of the acoustic tank and unmeasured zone of the experimental model due to the supporting structure for it. In this study, the effect of reflection wave in the acoustic tank and unmeasured area of the experimental model when using the NAH was investigated with experiment and numerical model. From these, it is known for the error due to reflection wave can be reduced when the distance between the measurement plane and source is being shorten. Also, unmeasured area of the experimental model gives rise to some error in the estimation of the far-field acoustic pressure.

• 대한물리치료과학회지
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• 제10권1호
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• pp.7-17
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• 2003

The purpose of this study was to investigate the effect of the involved lower limb weight bearing training on symmetrical weight supporting rate improvement and gait characteristics of patients with hemiplegia including their gait velocity, cadence, stride length, step length of the non affected side, step length of the affected side, foot angle of the non affected side, foot angle of the affected side, base of support, and so on. The subject of the study was 28 men and women patients with hemiplegia from 22 to 77 age, among patients who doctor diagnosed as hemiplegia due to stroke or traumatic brain injury, were possible to do independent gait more than 45m without others assistance, the flexion contracture of hip pint was less than $15^{\circ}$, did not have contracture for knee pint and one more than $5^{\circ}$ for ankle joint, did not have contraindication for exercise or gait did not show visual defect due to brain injury. The patients, the subject of the study, were classified into 14 patients of treatment. group applying continuous involved weight bearing with general therapeutic exercise and 14 patients of control group applying general therapeutic exercise, and then analyzed their gait before and after exercise. Temporal distance gait analysis(Boening, 1977) was used to analyze their gait, and ink foot-print was applied as one of measurement methods. However, it was statistically signifiant in the change rate(%) of gait characteristics, and treatment group's patients with hemiplegia had been highly changed in gait characteristics in comparison with control group. From the above-mentioned results, could find that continuous involved weight bearing training for patients with hemiplegia was effective to improve their gait ability and it could increase the ability in comparison with general exercise.

• 한국측량학회지
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• 제20권2호
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• pp.111-118
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• 2002

오늘날 측량장비 개발의 급속한 발전과 더불어 정밀도가 많이 향상되고 있고 컴퓨터를 이용한 지형공간정보체계기술의 발달로 더욱 정밀한 3차원 지형의 재현이 가능하게 되었다. 그런데 실제 현장에서 이루어지고 있는 면적 및 체적산출방법에 있어서는 재래적인 측량방법인 평판측량으로 지형을 만들어낸 후 구적기나 기타 다른 방법을 통해서 2차원 면적을 산출한다. 여기에 일정량의 경사보정계수를 곱하여 3차원 면적을 산출하는 방법을 사용하고 있다. 본 연구에서는 재래적인 측량방법 및 면적산출방법에 대한 비효율성 및 비정밀성을 제시하고 광파거리측량기와 GPS를 이용하여 불규칙삼각형방식과 격자형방식으로 측량을 실시하였다. 두 가지 측량데이터를 가지고 각각의 방법에 따라 3차원 지형모델을 구축한 후 2차원 및 3차원 면적을 산출하였으며 재래적인 측량방법을 이용한 면적산출량을 기준으로 불규칙삼각형방식과 격자형방식으로 산출한 면적산출량을 비교 분석함으로써 정밀하고 효율성이 높은 3차원 면적산출기법을 제시하였다.