• Journal of Korean Neurosurgical Society
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• 제30권9호
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• pp.1094-1102
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• 2001

Objective : During the trans-condylar or trans-jugular approach for the lesion of cranio-cervical junction(CCJ), its necessary to identify the accurate locations of vertebral artery(VA), internal jugular vein(IJV) and its related lower cranial nerves. These neurovascular structures can also be damaged during the operation for vascular tumor or traumatic aneurysm around extra-jugular foramen, because of their changed locations. To reduce the neurovascular injury at the operation for CCJ, morphometric relationship of its surrounding neurovascular structures based on the tip of the transverse process of atlas(C1 TP), were studied. Materials & Methods : Using 10 adult formalin fixed cadavers, tip of mastoid process(MT) and TPs of atlas and axis were exposed bilaterally after removal of occipital and posterior neck muscles. Using standard caliper, the distances were measured from the C1 TP to the following structures : 1) exit point of VA from C1 transverse foramen, 2) branching point of muscular artery from VA, 3) entry point of VA into posterior atlanto-occipital membrane(AOM), 4) branching point of C-1 nerve. In addition, the distances were measured from the mid-portion of the posterior arch of atlas to the entry point of the VA into AOM and to the exit point of the VA from C1 transverse foramen. After removal of the ventrolateral neck muscles, neurovascular structures were exposed in the extra-jugular foraminal region. Distances were then measured from the C1 TP to the following structures : 1) just extra-jugular foraminal IJV and lower cranial nerves, 2) MT and branching point of facial nerve in parotid gland. In addition, distance between MT and branching point of facial nerve was measured. Results : The VA was located at the mean distance of 12mm(range, 10.5-14mm) from the C1 transverse foramen and entered into the AOM at the mean distance of 24mm(range, 22.8-24.4mm) from the C1 TP. The mean distance from the mid portion of the C1 posterior arch was 20.6mm(range, 19.1-22.3mm) to the entry point of the VA into AOM and 38.4mm(range, 34-42.4mm) to the exit point of the VA from C1 transverse foramen. Muscular artery branched away from the posterior aspect of the transverse portion of VA below the occipital condyle at the mean distance of 22.3mm(range, 15.3-27.5mm) from the C1 TP. The C-1 nerve was identified in all specimens and ran downward through the ventroinferior surface of the transverse segment of VA and branched at the mean distance of 20mm(range, 17.7-20.3mm) from the C1 TP. The IJV was located at the mean distance of 6.7mm(range, 1-13.4mm) ventromedially from the lateral surface of the C1 TP. The XI cranial nerve ran downward on the lateral surface of the IJV at the mean distance of 5mm(range, 3-7.5mm) from the C1 TP. Both IX and X cranial nerves were located in the soft tissue between the medial aspect of the internal carotid artery(ICA) and the medial aspect of the IJV at the mean distance of 15.3mm(range, 13-24mm) and 13.7mm(range, 11-15.4mm) from the C1 TP, respectively. The IX cranial nerve ran downward ventroinferiorly crossing the lateral aspect of the ICA. The X cranial nerve ran downward posteroinferior to the IX cranial nerve and descended posterior to the ICA. The XII cranial nerve was located between the posteroinferior aspect of the IX cranial nerve and the posterior aspect of the ICA at the mean distance of 13.3mm(range, 9-15mm) ventromedially from the C1 TP. The distance between MT and C1 TP was 17.4mm(range, 12.5-23.9mm). The VII cranial nerve branched at the mean distance of 10.2mm(range, 6.8-15.3mm) ventromedially from the MT and at the mean distance of 17.3mm(range, 13-21mm) anterosuperiorly from the C1 TP. Conclusion : This study facilitates an understanding of the microsurgical anatomy of CCJ and may help to reduce the neurovascular injury at the surgery around CCJ.

• 한국자동차공학회논문집
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• 제4권3호
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• pp.83-91
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• 1996

This paper investigates the energy absorption characteristics of thin-walled rectangular tubes. In the compact mode, the crushing process of a thin-walled tube is analyzed into 3 parts by the ratio of outward to inward fold length. The mean crush load and the half-wave folding length are determined by using minimum energy principle. The effective crush distance can be determined when half-wave folding length is known, and the number of folds is derived when crush distance is given. Thus when the crush distance is given, energy absorption capacity can be estimated with mean crush load and number of folds. And the theoretical value is proven experimentally.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2010년 춘계학술발표회 논문집
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• pp.253-255
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• 2010

항공사진측량과 위성영상측량에서 거리측정정확도에 대한 연구의 필요성이 급증하고 있다. 그러나 기존 연구들에서는 표준편차와 제곱평균편차간은 물론이고 측정정확도와 측정정밀도간의 정의에 대한 경향성 있는 혼동된 이해가 들어있다. 따라서 본 연구는 항공사진측량과 위성영상측량에서 거리정확도에 관한 표준편차와 제곱평균편차간은 물론이고 측정 정확도와 측정 정밀도간의 관계에 대한 제한적인 정의를 제안한다. 실험결과는 제안한 정확한 정의가 거리측정 정밀도가 아닌 항공사진측량과 위성영상측량에서 거리정확도에서의 개선을 가져옴을 보여준다.

• 대한기계학회논문집B
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• 제24권10호
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• pp.1300-1308
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• 2000

The objectives of this study was to investigate the spray characteristics of single spray and twin spray in the overlap region such as mean axial velocity, mean radial velocity, mean droplet size and probability density function of droplet size. A phase doppler anemometer was used as the measurement system for droplet size and velocity. In case of single spray, injection pressure was varied from 0.2MPa to 0.7MPa. Mean axial velocity, mean radial velocity and droplet size were decreased as the distance below nozzle tip was increased. In case of twin spray, the spray characteristics were measured by varying the distance between two nozzles from 127mm to 155mm. In the overlap region, the boundary of the overlap region was determined by obtaining the distribution of mean axial and radial velocity. Droplet size was increased as the distance from nozzle tip was increased. It was found that the distribution of droplet size for twin spray in the overlap region was different to single spray.

• 한국정보통신학회논문지
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• 제19권12호
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• pp.3011-3016
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• 2015

단백질의 삼차원 구조를 단백질의 국부적 구조인 단백질 조각의 일차원적 나열로 표현하면, 단백질 구조의 분석, 모델링, 탐색, 예측 등에 효과적으로 응용될 수 있다. 본 논문에서는 자연 상태의 단백질 구조를 정확하게 나타낼 수 있는 단백질 조각 라이브러리를 구성하기 위하여, 대규모 단백질 구조 자료를 이용 할 수 있는 거리 척도들의 효과적인 조합을 조사하였다. 단백질 조각 라이브러리를 구성하기 위해 군집화를 사용하였다. 초기 군집화 단계에서는 가장 계산량이 작은 내부 알파탄소간 거리를 사용하였고, 군집의 확장단계에서는 내부 알파탄소간 거리, 비네-코시거리와 평균 제곱근 오차를 조합하여 사용하였다. 제안한 거리 척도의 조합으로 대규모 자료를 이용하여 단백질 조각 라이브러리를 구성하였다. 구성된 라이브러리를 사용하여 단백질 구조를 나타내는 실험에서 작은 평균 제곱근 오차가 발생함을 확인하였다.

• 한국정보과학회논문지:소프트웨어및응용
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• 제36권6호
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• pp.479-490
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• 2009

여러 가지 실세계 문제들은 마르코프 결정 문제(Markov decision problem) 들로 형식화하여 풀 수 있으나, 풀이 과정의 높은 계산 복잡도 때문에 실세계 문제들을 직접적으로 다루는 데 많은 어려움이 있다. 이를 해결하기 위해 많은 시간적 추상화(Temporal abstraction) 방법들이 제안되어 왔고 이를 자동화하기 위한 여러 방법들 또한 연구되어 왔으나, 이들 방법들은 명시적인 효율성 척도를 갖고 있지 않아 이론적인 성능 보장을 하지 못하는 문제가 있었다. 본 연구에서는 문제의 크기가 커지더라도 좋은 성능이 보장되는 자동적인 시간적 추상화 구현 방법에 대해 제안한다. 이를 위하여 네트워크 척도(Network measurements)를 이용하여 마르코프 결정 문제의 풀이 효율과 상태 궤적 그래프(State trajectory graph)의 위상 특성간의 관계를 분석하고, 네트워크 척도들 중 평균 측지 거리(Mean geodesic distance)가 마르코프 결정 문제의 풀이 성능과 밀접한 관계가 있다는 사실을 알아내었다. 이 사실을 기반으로 하여, 낮은 평균 측지 거리를 보장하는 복잡계망 모델(Complex network model)을 사용하여 시간적 추상화를 만들어 나가는 알고리즘을 제안한다. 제안된 알고리즘은 사실적인 3차원 게임 환경을 비롯한 여러 문제에 대해 테스트되었고, 문제 크기의 증가에도 불구하고 효율적인 풀이 성능을 보여 주었다.

• 한국통신학회논문지
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• 제28권6C호
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• pp.624-633
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• 2003

본 논문에서는 MPEG-4 동영상을 완전히 디코딩하지 않은 상태에서 근사화된 형상 정보를 추출하여 형상의 유사도에 의해 VOP를 클러스터링 하여 VO의 동작을 요약, 검색하는 새로운 방법을 제안한다. 제안하는 형상 추출방법은 Erol의 방법을 단순화한 것으로서, 키 VOP 형상의 정확도는 개선되면서도 실행시간은 감소한다. 제안하는 방법에서는 근사화된 형상 사이의 유사도를 Normalized Mean Hausdorff Distance로 구하며, 이를 2-means 클러스터링하여 VOP를 선정한다. VOP 검색은 질의 형상과 키 VOP의 형상 사이의 Mean Hausdorff Distance를 계산하여 가장 일치하는 키 VOP를 선택하는 방식으로 이루어진다. 제안하는 방법을 표준 MPEG-4 테스트 영상 열에 대해 시험한 결과, 기존의 방법에 비해 근사화된 형상 정보를 더 짧은 시간에 얻을 수 있고, 재귀적 클러스터링 방법을 사용하여 키 VOP들의 정확도도 개선되었다.

• 한국운동역학회지
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• 제24권2호
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• pp.151-160
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• 2014

The purpose of this study was to investigate the GRF(ground reaction force) parameters according to the shoes's heel heights and ground landing distances during downward stairs on bus. Participants selected as subject were consisted of young and healthy women(n=9, mean age: $21.30{\pm}0.48$ yrs, mean height: $164.00{\pm}3.05cm$, mean body mass: $55.04{\pm}4.41kg$, mean BMI: $20.47{\pm}1.76kg/m^2$, mean foot length: $238.00{\pm}5.37mm$). They were divided into 2-types of shoe's heel heights(0 cm/bare foot, 9 cm) and also were divides into downward stairs with 3 types of landing distance(20 cm, 35 cm, 50 cm). A one force-plate was used to collect the GRF(AMTI, USA) data from the sampling rate of 1000 Hz. The GRF parameters analyzed were consisted of the medial-lateral GRF, anterior-posterior GRF, vertical GRF, loading rate, Center of Pressure(${\Delta}COPx$, ${\Delta}COPy$, COP area) and Dynamic Postural Stability Index(MLSI, APSI, VSI, DPSI) during downward stairs on bus. Medial-lateral GRF and vertical GRF didn't show significant differences statistically according to the shoe's heel heights and landing distance, but 9 cm shoes heel showed higher vertical GRF than that of 0 cm bare foot in landing distance of 50 cm. Also anterior-posterior GRF didn't show significant difference statistically according to the shoe's heel heights, but landing distance of 20 cm showed higher than that of landing distances of 35 cm and 50 cm in anterior-posterior GRF. Loading rate didn't show significant difference statistically according to the landing distance, but 9 cm shoe's heel showed higher than that of 0 cm bare foot during downward stairs. The ${\Delta}COPy$ and COP area didn't show significant differences statistically according to the shoe's heel heights and landing distance, but 0 cm bare foot showed higher than that of 9 cm shoe's heel in ${\Delta}COPx$. Dynamic Postural Stability Index(MLSI, APSI, VSI, DPSI) didn't show significant differences statistically according to the landing distance, but 9 cm shoe's heel showed decreased value than that of 0 cm bare foot in dynamics balance. Considering the above, parameters of GRF showed different characteristics according to the shoe's heel heights and ground landing distances during downward stairs on bus.

• 한국조경학회지
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• 제22권1호
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• pp.149-177
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• 1994

This study is practically focussed on the derivation of the formula of the reach of the catchment of urban community parks and the reached distance to the parks. The hypotheses for the formula are as follows. a. The catchment of urban community parks can be dependent on the quantitative characteristics that urban community parks have substanial factors : the potential residential population of the proximate community to a park, park visitor's day and mean usetime per year. b. The distance to the urban park is a decided variable which can be percieved quantitatively by the researchers among the exogenous variables concerned with the mean usetime of the urban community park. The data for the variables were collected from the statistics, and the surveys for 9 parks of 4cities(Seoul, Chong-ju, Su-Won, Chon-an) in Korea, which were divided into on-site samples and off-site ones in 1991. The data were collected by questionaire surveys. A total of 548 questionaires of off-site surveys were completed by the residents in the enticing area of the parks. A total of 1053 questionaires of on-site surveys were completed by the visitors of the parks. The research could attempt to derive a formula, which was concerned with the reach of the catchment of urban community parks and the reached distance to the parks. It is testified(R2>0.8) that the numbers of mean usetime per year should be related with the reached distance from a visitor's house to a proximate park. The formula is analogized with an exponential function: {{{{ Mean Usetime per year=f(x)=Ae-BK+Ce-DK ear, X is reached distance from a visitor's house to a proximate park. A,B,C and D are parameters. And, the differences of the reach of the catchment of the parks are not only testified with resulting from the differences of the exogenous variables of qualitative characteristics differences of the parks, but also divided separately into spatial ranges. This formula will be able to anticipate the visitor's numbers of a planned urban community park.

• Journal of Korean Neurosurgical Society
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• 제43권2호
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• pp.79-84
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• 2008

Objective: The length of anterior-posterior commissure (AC-PC) in racial groups, age, gender of patients with deep brain stimulation (DBS) and pallidotomy were investigated. Methods: From January 1996 to December 2003, 211 patients were treated with DBS and pallidotomy. There were 160 (76%) Caucasians, 35 (17%) Hispanics, 12 (5%) Asians and 4 Blacks (2%). There were 88 males and 52 females in DBS-surgery group and 44 males, 27 females in pallidotomy group. Mean age was 58 year-old. There were 19 males and 19 females and mean age was 54.7 years in the control group. Measurements were made on MRI and @Target software. Results: The average AC-PC distance was 24.89 mm (range 32 to 19), which increased with aging until 75 years old in Caucasian and also increased with aging in Hispanic, but the AC-PC distance peaked at 45 years old in Hispanic. The order of AC-PC distance were $24.6{\pm}2$ mm in Caucasian, $24.6{\pm}2.24$ mm in Asian, 24.53 mm in Black, $23.6{\pm}1.98$ mm in Hispanic. The average AC-PC distance in all groups was 24.22 mm in female who was mean age of 56.35, 25.28 mm in male who was mean age of 60.19 and $24.5{\pm}2$ mm in control group that was excluded because of the difference of thickness of slice. According to multiple regression analysis, the AC-PC distance was significantly correlated with age, race, and gender. Conclusion: The AC-PC distance is significantly correlated with age, gender, and race. The atlas of functional stereotaxis would be depended on the Variation of indivisual brain that can influenced by aging, gender, and race.