• Proceedings of the Korea Information Processing Society Conference
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• 2000.10a
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• pp.191-194
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• 2000

본 논문에서는 기존의 정렬 알고리즘의 성능을 향상시키기 위하여 정보블록 전처리 알고리즘(IBPA)이라는 전처리알고리즘을 제안한다. IBPA는 정렬될 리스트(list)에 있는 데이터에 관한 정보를 생성하고, 생성된 정보를 이용하여 각 데이터를 재배치하며, 실제적인 정렬은 기존의 정렬 알고리즘을 그대로 이용하여 이루어진다. IBPA의 성능을 측정해본 결과, 2백만개의 랜덤데이터를 정렬한 경우, O($N^2$)의 평균시간복잡도를 갖는 정렬알고리즘의 0.003%, O(NlogN) 의 평균시간복잡도를 갖는 정렬알고리즘의 52%, 그리고 O(N)의 평균시간복잡도를 갖는 정렬알고리즘의 89%정도의 비교회수만으로도 정렬할 수 있음을 보여주었다.

• Proceedings of the Korean Statistical Society Conference
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• 2001.11a
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• pp.175-178
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• 2001

다원분할표에서 범주들의 대응관계를 그래프적으로 보여주는 다중대응분석(multiple correspondence analysis)은 주결여성(principal inertia)이 총결여성(total inertia)에서 차지하는 비율이 전반적으로 낮아 설명력(goodness-of-fit)이 낮은 2차원의 대응분석그림을 얻게 된다. 이를 극복하기 위해 Benzecri의 공식을 사용하면 낮은 주결여성을 높이고 새로운 2차원 대응분석그림을 얻을 수 있다. 그러나 이 새로운 대응분석그림도 범주들의 대응관계를 명확히 보여주지는 못한다(Greenacre and Blasius, 1994, chapter 10). 앤드류 플롯(Andrews plot)을 이용하여 범주들의 군집화(clustering)로 다중대응분석을 재해석 하고자 하나 범주의 수가 많은 경우 해석상 어려움이 따른다. 본 소고에서 이와 같은 경우 K-평균 군집분석을 활용하여 다중대응분석의 해석을 용이하게 하고자 한다.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.254-255
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• 2013

본 논문에서는 저항센서와 바이패스 스위치를 이용한 평균 전류 모드 제어의 부스트 컨버터 저손실을 측정하는 방법을 제안한다. 일반적으로 저항을 이용한 전류센싱 방법은 손실을 가지며 이는 전체 시스템의 효율을 감소시키게 된다. 제안된 전류 측정 기법은 저항센서에 병렬로 바이패스 스위치를 적용하여 전류센서에서 발생되는 손실을 바이패스 스위치를 통해 손실을 최소화 할 수 있다. 본 논문에서는 50W급 평균 전류 모드 부스트 컨버터를 제작하여 바이패스 스위치를 통한 효율 개선을 아날로그 회로로 구현하여 검증하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.01a
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• pp.181-182
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• 2016

본 연구에서는 초등 교사가 교수-학습 활동에 있어 테크놀로지를 활용하는 정도와 TPACK 사이의 관계를 살펴보기 위하여 2015년 6월 10일부터 7월 10일까지 웹 기반 설문을 통하여 수집된 140명의 응답 자료를 분석하였다. 조사 결과 수업에 활용하는 테크놀로지의 수는 평균 1.39개였으며, 테크놀로지를 활용한 수업을 하는 과목의 수는 평균 3.09 과목이었다. 수업에 활용하는 테크놀로지의 수와 테크놀로지를 활용한 수업의 수를 환산하여 활용 정도로 나타낸 결과의 평균은 1.72였으며, 이는 초등교사의 TPACK과 유의확률 0.01 수준에서 .227의 양의 상관을 보였다.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06c
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• pp.458-462
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• 2010

본 논문은 X-선 혈관조영영상에서 기울기 정보 및 최대 빈도수를 이용한 카테터 자동 분할 방법을 제안한다. 제안방법은 세 단계로 이루어진다. 첫째, 분할하고자 하는 카테터 관심영역을 설정하고, 영상의 대조대비를 높이기 위한 밝기값 스트레칭을 수행한다. 둘째, 카테터 후보 경계점을 추출하기 위하여 카테터 방향을 고려한 경계 강조 마스크를 영상에 적용한다. 셋째, 카테터 후보 경계점에서 기울기가 크고 최대 빈도수 직경을 갖는 카테터 경계점을 추출하고 이들을 선형 보간하여 최종 카테터 경계를 분할한다. 제안 방법의 평가를 위하여 육안 평가 및 전문가가 수동 분할한 결과와 본 제안방법을 적용하여 얻은 중복 영역 비율과 평균 거리 차이를 측정한 정확성 평가를 수행하였고, 수행시간을 측정하였다. 실험결과 중복 영역 비율은 93.9%${\pm}$2.7%, 평균 거리 차이는 0.116-픽셀, 수행시간은 평균 0.011초로 측정되었다.

• Journal of Chest Surgery
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• v.29 no.7
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• pp.769-776
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• 1996

The application of video-assisted thoracic surgery (VATS) in the examination of the thoracic cavity can be a new option in patients with mediastinal tumor because it provides outstanding visibility of the structures of the mediastinum. By clear viewing through the thoracoscope, a mediastinal tumor can be biopsied or resected, depending on the findings during an operation. We reviewed all patients who underwent curative or diagnostic operations from March 1990 to August 1995 under the impression of a mediastinal mass. The total number of patients were 113 with 59 males and 54 females. Group A underwent resection of tu or by thoracotomy(38 patients: 18 males, 20 females), and group B underwent resection of tumor by VATS (36 patients : 20 males and 16 females). Seven patients in group B were excluded because they underwent thoracotomy due to pleural adhesion or intra-operative bleeding ; therefore, the true VATS group numbered 29 cases. Group C underwent Iymph node biopsy by VATS(33 patients'16 males, 17 females), and group D(6 patients: 5 males, 1 female) underwent Iymph node biopsy through anterior mediastinotomy. The mean age in group A was 36.2 years compared to 41.3 years In group B. We compared operation time, frequency of injection for pain control, duration of chest tube insertion, postoperative hospital stay, and diagnostic yield. In group A, they were 164 minutes, 3.4 times, 5.2 days, and 11.3 days, respectively, in comparison to 152 minutes, 2 times, 4.7 days, and 8.3 days, respectively, in group B. These data revealed that the day of discharge was significantly shorter in group B (p valu : 0.03). In group C, the mean age was 45.8 years (range 1 ∼70). The operation time was from 30 to 335 minutes (mean 105), pain control was required from 0 to 15 times(mean 3.2), and a chest tube was needed for 1 to 36 days (mean 6.1). In group D, mean age was 53.3 years, operation time 121 minutes, pall control injec- tion frequency 2.6 times, and mean chest tube duration 10.5 days. The diagnostic yield in group C was 8 oyo compared to 100 oyo in group D although the number of patients in group D is small.

• The Journal of Engineering Geology
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• v.26 no.3
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• pp.383-392
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• 2016

This study is to evaluate the physical and mechanical properties on the Ipseok-dae columnar joints of Mt. Mudeung National Park. For these purposes, physical and mechanical properties as well as discontinuity property on the Mudeungsan tuff, measurement of vibration and local meteorology around columnar joints, and ground deformation by self-weight of columnar joints were examined. For the physical and mechanical properties, average values were respectively 0.65% for porosity, 2.69 for specific gravity, 2.68 g/cm³ for density, and 2411 m/s for primary velocity, 323 MPa for uniaxial compressive strength, 81 GPa Young's modulus, and 0.25 for Poisson's ratio. For the joint shear test, average values were respectively 3.15 GPa/m for normal stiffness, 0.38 GPa/m for shear stiffness, 0.50 MPa for cohesion, and 35° for internal friction angle. The JRC standard and JRC chart was in the range of 4~6, and 1~1.5, respectively. The rebound value Q of silver schmidt hammer was 57 (≒ 90 MPa). It corresponds 20% of the uniaxial compressive strength of intact rock. The maximum vibration value around the Ipseok=dae columnar joints was in the range of 0.57 PPV (mm/s)~2.35 PPV (mm/s). The local meteorology of surface temperature, air temperature, humidity, and wind on and around columnar joints appeared to have been greatly influenced the weather on the day of measurement. For the numerical analysis of ground deformation due to its self-weight of the Ipseok-dae columnar joints, the maximum displacement of the right ground shows when the ground distance is approximately 2 m, while drastically decreased by 2~4 m, thereafter was insignificant. The maximum displacement of the middle ground shows when the ground distance is approximately 0~2 m, while drastically decreased by 3~10 m, thereafter was insignificant. The maximum displacement of the left ground shows when the ground distance is approximately 5~6 m, while drastically decreased by 6~10 m, thereafter was insignificant.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.4
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• pp.672-679
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• 1996

In order to examine the quality attributes of native-bee honey, proximate composition and mineral components were analysed by atomic absorption spectrometry, ion chromatography and high performance liquid chromatography. The analytical results showed that native-bee honey is higher in the contents of crude ash, crude protein and diastase activity than those of foreign-bee honey. The principal mineral components of honey were Ca, Mg, Na, K and Cl, which showed that almost all the mineral components were contained higher in the native-bee honey than the foreign-bee honey samples. When we calculated K/Na ratio, we could make a clear distinction between native-bee honey and foreign-bee honey. The K/Na ratio turned out to be more than 10 in 6 samples of native-bee honey, whereas the ratio of foreign-bee honey showed up less than 1.5 in all 3 samples.

• Development and Reproduction
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• v.10 no.2
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• pp.141-146
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• 2006

Genotype data from seven microsatellites typed in 231 animals were used to estimate the genetic structures of eight cow population distributed by regional area in Hanwoo (Korean cattle). In total, 53 alleles were detected from the genotyping of seven microsatellite markers. The average of expected heterozygosities ranged from 0.682 to 0.734 in 8 population of Hanwoo. Even though there were also some of alleles that were found in only specific regional population, similar frequency pattern for the most of alleles appeared in various 8 population. Genetic distances between populations were obtained using STDUPGMA method to construct a phylogenetic tree. The tree illustrated that most individuals were grouped on the basis of populations, distributed by the regional area. Some of genetic parameter on the basis of microsatellite gonotyping appears to provide a useful tool for examining the regional area kindship and genetic variation in Hanwoo.

• Korean Journal of Plant Resources
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• v.22 no.1
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• pp.1-4
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• 2009

This study was carried out to evaluate ecological growth characteristics of forty castor bean collections for biodiesel utilization. The emergence date and it's rate of collections was 15-16 days and 82.5%, respectively. It took 63-68 days from emergence to flowering. Stem length was ranged from 173 to 251 cm with an average 211.8 cm. The average stem diameter was 24.2 cm, and showed the high occurrence as 52.5% at the 20.4-24.9 cm. The node number was widely distributed as 13-22 and the average node number was 18.9. The seed numbers were widely distributed as 7-33ea, and the average liter weight of seed was 502.9 g of which minimum weight was 432.3 g and maximum weight was 572.5 g, and the gap between maximum and minimum was 140.2 g. It showed high difference. The 100 grain weight was distributed as 20.3 g-38.3 g which showed high differences between small grain and large grain collections. The seed numbers per plant were varied as 72 at the minimum and 1,011 at the maximum number, and average seed number was 465.2. The total yields of seed per plant were varied as 20 g-266.2 g, and the average yields were 128.1 g.