• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.729-734
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• 2003

This paper reports the characteristics of the three dimensional turbulent flow in the rectangular-sectioned 180 degree bends by Hot-wire anemometer. Grande and Kool proposed a cooling law for the measurements of the flow through the narrow passage. The authors noticed that the calibration coefficients of original method are not constant and fairly sensitive to the flow approaching angle. Measured voltages are converted to three velocity and six Reynolds stress components using the modified method in which the coefficients are treated as a function of approaching angle.

• ETRI Journal
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• 제43권4호
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• pp.594-602
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• 2021

Recently, quantitative and repetitive inspections of the old urban area were conducted because many structures exceed their designed lifetime. The health of a building can be validated from the condition of the outer wall, while the slant angle of the wall widely serves as an indicator of urban regeneration projects. Mostly, the inspector directly measures the inclination of the wall or partially uses 3D point measurements using a static light detection and ranging (LiDAR). These approaches are costly, time-consuming, and only limited space can be measured. Therefore, we propose a mobile mapping system and automatic slant map generation algorithm, configured to capture urban environments online. Additionally, we use the LiDAR-inertial mapping algorithm to construct raw point clouds with gravity information. The proposed method extracts walls from raw point clouds and measures the slant angle of walls accurately. The generated slant angle map is evaluated in indoor and outdoor environments, and the accuracy is compared with real tiltmeter measurements.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.975-978
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• 2009

Even if auto-stereoscopic and polarization based 3D displays are not working with the same principles, their common aim is to provide two different images in the eyes of the observer. In this paper we show that Fourier optics instrument for viewing angle measurements can be applied to both types of displays. Luminance measurements are made at different locations and what will be seen by an observer in front of the display is predicted. Precise 3D characteristics can be derived and direct comparison becomes possible.

• 대한소아치과학회지
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• 제44권2호
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• pp.129-137
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• 2017

본 연구의 목적은 파노라마 영상과 측모두부 영상에서 유의미한 상관관계를 가지는 계측치를 확인하고, 그 관계를 수식화하는 것이다. 99명의 3급 부정교합 환자의 파노라마 영상과 측모두부 영상에서 gonial angle, 하악지 높이, 하악중절치에서 하악하연까지의 길이를 측정하여 평가하였다. 측정된 수치는 각각 대응 표본 T검증, Pearson's 상관관계 검정, 회귀 분석을 통해 평가하였다. 측모두부 영상에서의 gonial angle 평균값은 $127.50^{\circ}$, 파노라마 영상에서의 값은 $125.49^{\circ}$, 상관계수는 0.945(p < 0.001)로 나타났으며, 상관관계는 '측모두부 영상의 gonial angle = 0.920 ${\times}$ 파노라마 영상의 gonial angle + 12.072'로 나타낼 수 있다. 다른 계측치들 간의 상관관계는 gonial angle에 비해 낮게 나타났다. Gonial angle은 파노라마 영상과 측모두부 영상에서 모두 재현성 있게 측정 가능하며, 강한 양의 상관관계를 나타낸다. 파노라마 영상 또한 측모두부 영상과 같이 환자의 수직성장패턴을 평가하는데 도움을 주는 방법이다.

• 대한소아치과학회지
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• 제29권3호
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• pp.295-303
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• 2002

대부분의 악악면 부조화는 혼합치열기에 시작되는데 혼합치열기는 영구치열에서 이상적인 교합을 형성하는데 매우 중요한 역할을 하며 이 시기에 교합유도를 성공적으로 수행하기 위해서는 두부방사선 계측학적 표준치가 중요하다. 따라서 소아치과영역에서 큰 비중을 차지하는 부정교합치료에 참고자료로 사용하기 위하여 Downs 분석법에 의한 표준치가 과거와 비교해서 변화가 있는지를 알아보고 인종간의 차이를 알아보고자 정상교합에 해당하는 혼합치열기 아동을 대상으로 두부방사선 계측학적 표준치를 조사하여 다음과 같은 결과를 얻었다. 1. Downs 분석법에 의해 한국인 성장기 아동의 연령군별 남녀별 두부방사선 규격사진 계측치의 기준치를 설정하였다. 2. 각 군에서 계측항목별로 남녀간의 유의한 차이는 없었으나 교합평면각, 상하악중절치각, 하악중절치와 교합평면이 이루는 각, 상악 중절치와 A-Pog간의 거리에서는 연령에 따라 유의한 차이가 있었다. 3. 안면각, AB plane angle, Y-axis, 하악중절치와 교합평면이 이루는 각, 하악중절치와 하악평면이 이루는 각, 상악중절치와 A-Pog간의 거리는 연령이 증가함에 따라 커졌으며, angle of convexity, 하악평면각, 교합평면각, 상하악중절치각등은 연령이 증가함에 따라 감소하였다. 4. 인종간 비교시 본 연구 결과가 백인과 그리스인보다 상하악절치각만 작았을 뿐 모든 계측치에서 전반적으로 크게 나타났으며, 일본, 이스라엘 흑인, 중국인과는 모든 항목에서 비슷한 수치를 나타냈다.

• The Journal of Korean Physical Therapy
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• 제22권3호
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• pp.55-59
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• 2010

Purpose: This study was designed to investigate the effect of a water exercise program on the pennation angle of the lower-limb muscle in women in their 20s. Methods: Ten female subjects were randomly divided into two groups, with 5 subjects exercising in water 0.7 m deep and 5 subjects exercising in water 1.4 m deep. They did the water exercising program for 40 minute per day, 3 days per week, for total 6 weeks. We measured the pennation angle of lower-limb muscle using ultrasonography. All measurements for each group were performed at pre-training and after 6 weeks of training. Results: The pennation angle was compared before and after the water exercise period for each group, and statistically significant changes within each group in measurements of the rectus femoris and tibialis anterior (p<0.05). However, there was no significant difference in muscle architecture by water depth (p>0.05) between the two groups. Conclusion: These results show that the pennation angle of the lower-limb muscle of women in their 20s changed after 6 weeks of participating in a water exercise program, but these changes were not dependent on the depth of the water in which the exercises were performed.

• 대한치과교정학회지
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• 제28권6호
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• pp.937-946
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• 1998

전치부 개교를 동반하는 수직적으로 긴 안모는 임상교정에서 치료하기 어려운 증례중 하나이다. 이런 증례의 특징을 찾기 위한 많은 시도가 있었으나 골격 및 치성 요소에 대한 개별 파악이 이루어지지 않음으로써 일관된 설명 없이 혼돈 만 초래하게 되었을 뿐이다. .수직적으로 긴 안모의 두부방사선계측학적 륵징을 확인하기 위하여 Sn-GoGn 각에 따라 구분된 109개의 치료 전 두부방사선사진 (35 수직군, 37 평균군, 37 수평군)을 분석하여 비교한 결과 다음과 같은 결과를 발견하였다. 수직적으로 긴 안모일수록 전안모고경, 특히 하전안모고경이 증가하며 후안모고경은 짧아지고, 모든 치조골, 특히 상악에서 의 두께가 깊어진다. 또한 모든 골격적 각계측항목이 커지는데 특히 lower genial angle의 상관성이 컸다. 한편 상악 전치는 점점 설측경사되었고 하악 전치는 순측경사되는 경향을 보였다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제27권3호
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• pp.231-238
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• 2001

This study was performed to evaluate soft tissue cephalometric norms for Korean adults which can be implemented in surgical orthodontic treatment planning using selected horizontal reference plane especially for Koreans (Male: $SN-7.5^{\circ}$, Female: $SN-9.0^{\circ}$) and a simplified analytical method. 70 males and 70 females consisting of freshmen of Yonsei University from 1996 to 1997 and students from the Dental College of Yonsei University were chosen according to clinical examination and cephalometric analysis. The samples had normal profiles, normal anteroposterior skeletal relationship(ANB angle of $0^{\circ}\;to\;4^{\circ}$ and Wits appraisal of -4.0mm to 0mm), and Class I molar and canine relationship. They had no missing or supernumerary teeth and had no experience of orthodontic or prosthetic treatment. After the selection of 15 soft tissue landmarks and the construction of horizontal and vertical reference lines, 25 measurements were taken. These consisted of vertical and horizontal linear measurements and angular measurements. The results were as follows. 1. Mean and standard deviation of the measurements were calculated in males and females. 2. Vertical measurements were comparably bigger in males than females whereas anterior facial height ratio(sN-Sn/Sn-sMe) and lower anterior facial height ratio(Sn-Stms/Stmi-sMe) showed no significant difference between sexes. 3. Most of the horizontal measurements in relation to the vertical reference line(G-perpendicular) showed no significant difference between sexes. 4. Nasofacial angle, columellar angle, nasolabial angle and facial contour angle showed no significant difference between sexes. 5. The upper and lower lip were positioned about $-1.0{\pm}2.0mm$ and $+1.0{\pm}2.0mm$ in relation to the Ricketts' esthetic line in both sexes. In this study, soft tissue cephalometric norms of Korean adults for orthognathic surgery were obtained.

• 대한족부족관절학회지
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• 제9권2호
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• pp.188-192
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• 2005

Purpose: It is to analyze the clinical utility of radiograhpic measurements for the insertional Achilles tendinitis patients who have Haglund's deformity and to evaluate the radiographic values related to Haglund's deformity in normal Korean population. Materials and Methods: We used the angle of Fowler and Philip, parallel pitch lines (PPL) and Chauveaux-Liet (CL) angle as radiographic measurements. We examined 50 cases of insertional Achilles tendinits patients and another 50 cases of normal foot as a control. Results: In normal feet, the mean value of angle of Fowler and Philip was $53.22^{\circ}$, CL angle was $-33.14^{\circ}$ and the PPL showed positive in 48%. In case of insertional Achilles tendinitis, the mean values were $55.39^{\circ}$, $-33.63^{\circ}$, positive in 56% respectively. There were not statistically significant differences (p>0.05). Conclusion: The radiographic values for Haglund's deformity between insertional Achilles tendinitis feet and the normal feet did not show significant difference. Therefore, it seems that the clinical utility of radiographic measurements for the insertional Achilles tendinitis with Haglund's deformity is not useful and the development of new diagnostic methods as MRI and ultrasonography is required.

• Smart Structures and Systems
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• 제33권2호
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• pp.119-131
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• 2024

Drift angle is a significant index for diagnosing post-event structures. A common way to estimate this drift response is by using modal parameters identified under natural excitations. Although the modal parameters of shear structures cannot be identified accurately in the real environment, the identification error has little impact on the estimation when measurements from several floors are used. However, the estimation accuracy falls dramatically when there is only one accelerometer. This paper describes the susceptibility of single sensor identification to modelling error and simulations that preliminarily verified this characteristic. To make a robust evaluation from measurements of one floor of shear structures based on imprecisely identified parameters, a novel scheme is devised to approximately correct the mode shapes with respect to fictitious frequencies generated with a genetic algorithm; in particular, the scheme uses constrained minimization to take both the mathematical aspect and the realistic aspect of the mode shapes into account. The algorithm was validated by using a full-scale shear building. The differences between single-sensor and multiple-sensor estimations were analyzed. It was found that, as the number of accelerometers decreases, the error rises due to insufficient data and becomes very high when there is only one sensor. Moreover, when measurements for only one floor are available, the proposed method yields more precise and appropriate mode shapes, leading to a better estimation on the drift angle of the lower floors compared with a method designed for multiple sensors. As well, it is shown that the reduction in space complexity is offset by increasing the computation complexity.