• 대한물리치료과학회지
• /
• 제30권1호
• /
• pp.31-40
• /
• 2023

Hamstring flexibility is an important factor that affects muscle performance of the lower extremities and is closely associated with sports injuries. Therefore, evaluation of flexibility is important in clinical practice. Results of evaluation are determined by types of tests and cut-off values used; therefore, accurate and detailed understanding of these is necessary before examination. Although the straight leg raise and sit and reach tests are used to evaluate hamstring extensibility, structures including the nerves, fascia, and other muscles can significantly confound the results of these tests. The knee extension test is performed at 90° of hip flexion to minimize the posterior pelvic tilt that occurs during the straight leg test. The knee extension test is most recommended for selective evaluation of hamstring flexibility. The knee extension test is classified into active and passive tests. The cut-off value is usually set at 20° for the active and at 10° for the passive knee extension test. Although a strong association is observed between the two tests, the active knee extension test is preferred in clinical practice because it can be performed by a single examiner, which serves as an advantage. Age, sex, and warm-up exercise tend to affect flexibility; therefore, results should be interpreted with caution. Detailed understanding of each flexibility test is important for reliable evaluation.

• 한국산업융합학회 논문집
• /
• 제26권6_2호
• /
• pp.1109-1115
• /
• 2023

The shell and tube-type heat exchanger was the most utilized in industrial field because of its simple structure and wide operation conditions and so on. This study was performed to investigate the characteristics of behavior of thermal flow according to operation condition of small-sized shell and tube-type heat exchanger. The operation conditions, here, were set up to flow rate of hot air with temperature of 100℃, number of baffle and cut rate of baffle(BCR) using numerical analysis. As the results, both mean relative pressure and relative pressure drop was increased with quadratic curve in case of less than BCR 25%, however, decreased linearly in case of more than BCR 25%. The collision with first baffle by flow velocity and temperature, of hot air, respectively, was depended on BCR. Further it showed that the behaviors between flow velocity and temperature were almost similar.

• 한국조경학회지
• /
• 제32권4호
• /
• pp.28-38
• /
• 2004

Korean goral (Nemorhaedus caudatus raddeanus) is one of the endangered species in Korea, and the rugged terrain of the Soraksan National Park (373㎢) is a critical habitat for the species. But the goral population is threatened by habitat fragmentation caused by roads and hiking trails. The objective of this study was to develop a potential habitat suitability model for Korean goral in the park, and the model was based on the concepts of fuzzy set theory and multi-criteria evaluation. The process of the suitability modeling could be divided into three steps. First, data for the modeling was collected by using field work and a literature survey. Collected data included 204 points of GPS data obtained through a goral trace survey and through the number of daily visitors to each hiking trail during the peak season of the park. Second, fuzzy set theory was employed for building a GIS data base related to environmental factors affecting the suitability of the goral habitat. Finally, a multiple-criteria evaluation was performed as the final step towards a goral habitat suitability model. The results of the study were as follows. First, characteristics of suitable habitats were the proximity to rock cliffs, scattered pine (Pinus densiflora) patches, ridges, the elevation of 700∼800m, and the aspect of south and southeast. Second, the habitat suitability model had a high classification accuracy of 93.9％ for the analysis site, and 95.7％ for the validation site at a cut off value of 0.5. Finally, 11.7％ of habitatwith more than 0.5 of habitat suitability index was affected by roads and hiking trails in the park.

• Clinical and Experimental Pediatrics
• /
• 제48권4호
• /
• pp.387-394
• /
• 2005

목 적 : 선천성 갑상선기능저하증에 대한 신생아 선별검사결과의 이상빈도는 실제 임상적으로 진단되는 질환의 발생빈도보다 훨씬 높다. 본원에서 시행되는 선천성 갑상선기능저하증에 대한 신생아 선별검사의 위양성률과 소환율을 알아보고 재태기간과 출생체중에 따른 검사결과치를 비교하여 각각의 결과에 따라 cut-off value를 재평가함으로써 임상에서 신생아 선별검사의 결과를 해석하고 질환을 진단하는데 도움을 주고자 하였다. 방 법 : 2000년 5월부터 2003년 1월까지 단국대학교병원에서 출생한 2,133명의 신생아를 대상으로 정상분만의 경우 생후 3일째, 제왕절개인 경우 생후 5일째, 신생아중환자실에 입원한 미숙아인 경우 생후 $14.3{\pm}12.4$일(5-79일) 이내에 신생아의 발뒤꿈치를 천자하여 모세혈을 검사용 채혈지에 묻혀 갑상선자극호르몬과 유리 $T_4$를 효소면역법으로 분석하였고 각각의 기존참고치인 $20{\mu}IU/mL$ 이상, 1 ng/dL 미만일 경우 소아과 외래로 불러 재검하였으며 이때 이학적 검사 및 주산기적 병력, 약물력, 모체질환 등의 여부를 조사하였고 혈청을 이용해 면역형광법에 의한 갑상선기능검사를 시행하였다. 결 과 : 1) 다른 질병이 없었던 1,749명의 갑상선자극호르몬과 유리 $T_4$의 평균${\pm}$표준편차는 각각 $9.01{\pm}5.82{\mu}IU/mL$, $1.99{\pm}0.90ng/dL$이었고 성별, 분만형태, 아프가 점수에 따른 차이는 없었다. 2) 재태연령과 출생체중에 따라 갑상선자극호르몬의 수치는 의미있는 차이가 없었고 유리 $T_4$의 수치는 의미있는 차이가 있었다(P<0.01). 3) 다른 질병이 있었던 384명의 갑상선자극호르몬과 유리 $T_4$의 평균${\pm}$표준편차는 각각 $9.17{\pm}7.22{\mu}IU/mL$, $1.52{\pm}0.75ng/dL$이었고, 건강한 신생아와 비교시 갑상선자극호르몬의 수치는 의미있는 차이가 없었고 유리 $T_4$의 수치는 의미있는 차이가 있었다(P<0.01). 4) 신생아 선별검사에서 131명이 소환되었고 재소환율은 7.48%이었으며, 이중 추적관찰이 가능했던 87명의 갑상선기능이 정상화된 기간은 출생체중과 의미있는 관계는 없었고, 출생주수와는 음의 상관관계를 보였다(P=0.042, Pearson 상관계수 -0.177). 5) 신생아 선별검사에서 재소환되어 선천성 갑상선기능저하증을 진단받은 환아는 모두 4명으로 2명은 갑상선자극호르몬 수치만 $20{\mu}IU/mL$ 이상이었고 2명은 유리 $T_4$ 수치만 1 ng/dL 미만이었으며, 3명은 건강한 신생아에, 1명은 질병이 있었던 군에 속했다. 6) Cut-off value를 본 연구에서 시행되었던 기준인 갑상선 자극호르몬이 $20{\mu}IU/mL$ 이상이거나 또는 유리 $T_4\;1\;ng/dL$ 미만인 경우 소환율, 양성예측률, 민감도, 특이도는 각각 7.48%, 2.29%, 75%, 92.6%이었다. 갑상선자극호르몬이 $20{\mu}IU/mL$ 이상이거나 유리 $T_4\;0.64\;ng/dL$ 미만인 경우에 소환율, 양성예측률, 민감도, 특이도가 각각 4.8%, 3.57%, 75%, 95.3%이었다. 결 론 : 결론적으로 선천성 갑상선기능저하증에 대한 신생아 선별검사에서 갑상선자극호르몬 및 유리 $T_4$ 모두를 선별검사로 사용하는 것은 타당하고, 현재의 cut-off value가 소환율이 높기는 하나 검사의 민감도를 고려할 때 cut-off를 바꾸기에는 문제가 있을 것으로 생각되며 향후 더 큰 대상군을 바탕으로 한 재평가가 필요하리라 생각된다.

• 터널과지하공간
• /
• 제16권6호
• /
• pp.451-466
• /
• 2006

DOM 시추코어에서 측정된 불연속면의 위치 및 방향성 자료를 이용하여 현장암반의 구조적 특성을 고려한 사면거동 해석이 가능하였다. 3차원 공간에서 설정된 절리들의 위치에 의거하여 붕락 현상이 발생된 개착사면의 추가적인 파괴양상을 예측하였으며, 개별 절리면의 붕락위해 가능성과 개착면 상에서의 trace 위치를 파악하여 세부적인 사면거동 양상을 파악하였다. 개착사면 횡단면에서 개별절리들의 파괴거동 양상과 사면체 블록형성을 대수학적으로 산출하여 사면 붕락심도를 규명하였다. 현장사면에 자동화 계측시스템을 설치하여 사면 거동에 대한 계측자료를 수집하였으며, DOM 시추공 내에 지중경사계를 설치하여 사면거동 양상을 횡단면 해석 결과와 대비시켜 분석하였다. 지중경사계를 이용하여 측정된 개착면의 표면변위 자료에 의거하여 사면 파괴시기를 예측할 수 있는 방법론을 고찰하였으며, 강우가 사면거동에 끼치는 영향성을 분석하였다.

• Geomechanics and Engineering
• /
• 제30권1호
• /
• pp.67-73
• /
• 2022

In this study, the fiber orientation distribution (FOD) is investigated using both micro-CT (computerized tomography) and image analysis of physically cut specimens prepared from Polyvinyl Alcohol (PVA) fiber reinforced cemented Toyoura sand. The micro-CT images of the fiber reinforced cemented sand specimens were visualized in horizontal and vertical sections. Scans were obtained using a frame rate of two frames and an exposure time of 500 milliseconds. The number of images was set to optimize and typically resulted in approximately 3000 images. Then, the angles of the fibers for horizontal sections and in vertical section were calculated using the VGStudio MAX software. The number of fibers intersecting horizontal and vertical sections are counted using these images. A similar approach was used for physically cut specimens. The variation of results of fiber orientation between micro-CT scans and visual count were approximately 4-8%. The micro-CT scans were able to precisely investigate the fiber orientation distribution of fibers in these samples. The results show that 85-90% of the PVA fibers are oriented between ±30° of horizontal, and approximately 95% of fibers have an orientation that lies within ±45° of the horizontal plane. Finally, a comparison of experimental results with the generalized fiber orientation distribution function 𝜌(θ) is presented for isotropic and anisotropic distribution in fiber reinforced cemented Toyoura sand specimens. Experimentally, it can be seen that the average ratio of the number of fibers intersecting the finite area on a vertical plane to number of fibers intersecting the finite area on a horizontal plane (N^V_tot/N^H_tot) cut through a sample varies from 2.08 to 2.12 (an average ratio of 2.10 is obtained in this study). Based up on the analytical predictions, it can be seen that the average N^V_tot/N^H_tot ratio varies from 2.13 to 2.17 for varying n values (an average ratio of 2.15).

• 한국터널지하공간학회 논문집
• /
• 제12권2호
• /
• pp.157-164
• /
• 2010

최근 아치슬래브를 이용한 새로운 반개착식 터널공법이 터널안정성 확보와 건설비용 감소, 환경훼손 최소화를 위해 적용되고 있다. 반개착식 공법은 원지반을 터널 천단아치부 까지만 굴착하고 아치형 구조물을 설치하여 복토한 후에 터널하반을 굴착하는 공법이다. 본 논문에서는 편경사 지역에서 반개착식으로 굴착 할 경우 편경사에 따른 아치슬래브의 거동을 실내모형실험으로 규명하였다. 연구결과, 아치슬래브의 거동은 원지반의 편경사 크기, 굴착심도, 굴착사면의 경사 및 기반암의 위치에 영향을 받는 것으로 나타났다. 아치슬래브의 측력은 전반적으로 압축력이 지배하나 편경사가 커질수록, 저지대에서 부분적으로 인장력이 발생하였다. 아치슬래브의 모멘트는 편경사가 증가할수록 고지대에서는 압축모멘트가 발생하며, 저지대에서는 인장모멘트가 발생하였다. 지점반력은 편경사가 커질수록 고지대에서는 증가하며, 저지대에서는 감소하여 좌우편차가 발생하였다.

• 한국농공학회논문집
• /
• 제48권5호
• /
• pp.51-60
• /
• 2006

In order to examine the heat transfer characteristic of a soil warming system and effects of soil warming on the greenhouse heating load, control experiments were performed in two greenhouses covered with double polyethylene film. One treated the soil warming with an electric heat wire and the other treated a control. Inside and outside air temperature, soil temperature and heat flux, and heating energy consumption were measured under the set point of heating temperature of $5,\;10,\;15,\;and\;20^{\circ}C$, respectively. Soil temperatures in a soil warming treatment were observed $4.1\;to\;4.9^{\circ}C$ higher than a control. Heating energy consumptions decreased by 14.6 to 30.8% in a soil warming treatment. As the set point of heating temperature became lower, the rate of decrease in the heating energy consumptions increased. The percentage of soil heat flux in total heating load was -49.4 to 24.4% and as the set point of heating temperature became higher, the percentage increased. When the set point of heating temperature was low in a soil warming treatment, the soil heat flux load was minus value and it had an effect on reducing the heating load. Soil heat flux loads showed in proportion to the air temperature difference between the inside and outside of greenhouse but they showed big difference according to the soil warming treatment. So new model for estimation of the soil heat flux load should be introduced. Convective heat transfer coefficients were in proportion to the 1/3 power of temperature difference between the soil surface and the inside air. They were $3.41\;to\;12.42\;W/m^{2}^{\circ}C$ in their temperature difference of $0\;to\;10^{\circ}C$. Radiative heat loss from soil surface in greenhouse was about 66 to 130% of total heating load. To cut the radiation loss by the use of thermal curtains must be able to contribute for the energy saving in greenhouse.

• 항공우주기술
• /
• 제10권2호
• /
• pp.56-64
• /
• 2011

최근 위성 시스템의 전력분배는 기존의 퓨즈와 릴레이로 구성된 것과는 달리 LCL(Latching Current Limiter) 회로로 구현되어, 각각의 부하전원을 단속한다. LCL은 부하에서 생기는 과전류를 제한함으로서 고장 의심이 있는 부하를 물리적으로 차단하는 기존 방법에 비하여 고장의 원인을 분석하고, 일시적인 고장인 경우 부하를 재사용할 수 있는 장점이 있다. 그러나 LCL 회로는 전자소자로 구현되는 만큼 주변회로(부하회로)와의 연동성과 회로 자체의 특성을 이해해야 하며, 무엇보다 과전류를 차단하기 위하여 설정하는 LCL 동작 파라미터의 정의를 위한 기술적인 접근이 요구된다. 따라서 본 논문에서는 전력분배 모듈의 LCL 동작 파라미터를 정의하기 위한 분석을 수행했고, 회로구현 및 특성 시험결과를 나타냈다.

• Kyungpook Mathematical Journal
• /
• 제53권3호
• /
• pp.435-457
• /
• 2013

Using the Lukasiewicz 3-valued implication operator, the notion of an (${\alpha},{\beta}$)-intuitionistic fuzzy left (right) $h$-ideal of a hemiring is introduced, where ${\alpha},{\beta}{\in}\{{\in},q,{\in}{\wedge}q,{\in}{\vee}q\}$. We define intuitionistic fuzzy left (right) $h$-ideal with thresholds ($s,t$) of a hemiring R and investigate their various properties. We characterize intuitionistic fuzzy left (right) $h$-ideal with thresholds ($s,t$) and (${\alpha},{\beta}$)-intuitionistic fuzzy left (right) $h$-ideal of a hemiring R by its level sets. We establish that an intuitionistic fuzzy set A of a hemiring R is a (${\in},{\in}$) (or (${\in},{\in}{\vee}q$) or (${\in}{\wedge}q,{\in}$)-intuitionistic fuzzy left (right) $h$-ideal of R if and only if A is an intuitionistic fuzzy left (right) $h$-ideal with thresholds (0, 1) (or (0, 0.5) or (0.5, 1)) of R respectively. It is also shown that A is a (${\in},{\in}$) (or (${\in},{\in}{\vee}q$) or (${\in}{\wedge}q,{\in}$))-intuitionistic fuzzy left (right) $h$-ideal if and only if for any $p{\in}$ (0, 1] (or $p{\in}$ (0, 0.5] or $p{\in}$ (0.5, 1] ), $A_p$ is a fuzzy left (right) $h$-ideal. Finally, we prove that an intuitionistic fuzzy set A of a hemiring R is an intuitionistic fuzzy left (right) $h$-ideal with thresholds ($s,t$) of R if and only if for any $p{\in}(s,t]$, the cut set $A_p$ is a fuzzy left (right) $h$-ideal of R.