• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권4호
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• pp.334-345
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• 2005

The purpose of this study was to compare the postoperative stability and relapse according to 2 different fixation methods after bilateral sagittal split ramus osteotomies in mandibular prognathic patients. Tweenty one patients with Class III dental and skeletal malocclusion who were treated with bilateral sagittal split ramus osteotomy were selected for this retrospective study. We classfied the patients into two groups according to the fixation methods of bony segments after osteotomies. Group W (n = 10) had the bone segments fixed with nonrigid wire and Group S (n = 11) had bicortical screws inserted in the gonial area through a transcutaneous approach. Cephalometric radiographs were taken preoperatively, immediate postoperatively and more than six months postoperatively in each patient. After tracing the cephalometric radiographs, various parameters were measured. Before surgery, both groups were balanced with respect to linear and angular measurements of craniofacial morphology. Mean posterior sagittal setback amounts of the mandibular symphysis was 8.6 mm in the wire group and 6.79 mm in the rigid group, Six months postoperatively, the wire group had 33.1% relapse of the mandibular symphysis and 22.8% in the rigid group relapse. Both groups experienced changes in the orientation and configuration of the mandible. It is thought that Rigid screw fixation is a more stable method than nonrigid wire fixation for maintaining mandibular setback after sagittal split ramus osteotomy.

• Journal of Plant Biology
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• 제19권2호
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• pp.37-40
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• 1976

The experiment designed to obtain information relative to the favourable levels to apply N.P.K fertilizer was conducted at the hop garden of College of Agriculture, S.N.U. in 1975. The varieties used were 1-year-old Cascade, Hallertau and Shinshuwase. The design of the experiment was a split plot design with 3 replications. Yields were recorded as fresh weight of harvested cones in gram per split plot. The results obtained from the experiment were as follows: 1. The results from analysis of the data for 3 varieties indicated that significant increase in yield were found due to the application of 46g N, 20g P2O5 and 60kg K2O per plant, although higher level thn the above caused a remarkable reduction of yield. 2. The individual fresh weight of harvested cones was significantly increased with application of nitrogen, phosphorus and potash, regardless of fertilizer levels. 3. Analysis of variance for yields showed that there were no significant interaction between fertilizer level and variety, i.e., all varieties used might require the same fertilizer level.

• 수산해양기술연구
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• 제52권4호
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• pp.318-324
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• 2016

Commercial split beam echosounder (ES70) installed on a krill fishing vessel was calibrated in order to utilize it in estimating biomass of Antarctic krill (Euphausia superba). The method of calibration was to analyze the difference between the bottom backscattering strength of the commercial split beam echosounder (i.e. ES70) and the scientific echosounder (i.e. EK60) at one of transects near South Shetland Islands designated by CCAMLR. 38 kHz and 120 kHz were used for the calibration, and krill swarm signal levels obtained from multi frequencies, was examined to verify the calibration result. The analysis result indicated possibility of calibration by bottom backscattering strength, since the proportion of krill swarm signals within 2 dB < $S_{V\;120\;kHz-38\;kHz}$ < 12 dB (i.e. a common $S_{V\;120\;kHz-38\;kHz}$ range of 38 kHz and 120 kHz to be an indicator of Antarctic krill) over the total acoustic signals were 26.95% and 92.04%, respectively before and after the calibration.

• 대한기계학회논문집B
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• 제39권10호
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• pp.787-793
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• 2015

초임계 이산화탄소($S-CO_2$) 사이클은 소형화된 터보기계 및 열교환기를 통해서 작은 공간에서도 높은 열효율로 전력을 생산할 수 있는 잠재력을 가진 것으로 평가되고 있으며, 최근 이에 대한 관심이 증가하고 있다. 원자력 및 태양열(CSP) 분야에서 $S-CO_2$ 사이클에 대한 연구 결과가 다수 소개되어 온 반면, 폐열 분야에 대한 연구 결과는 상대적으로 많지 않다. 본 연구에서는 폐열 회수 응용 분야에 있어서, 예열에 의한 $S-CO_2$ 사이클의 성능 향상 가능성을 살피기 위하여, 재생 $S-CO_2$ 브레이튼 사이클과 예열기를 갖는 재생 $S-CO_2$ 브레이튼 사이클을 모델링하고 시뮬레이션 하였다. 시뮬레이션 결과, 순출력을 극대화시키는 최적 $CO_2$ 분기율이 존재함을 확인하였다. 본 연구의 시뮬레이션 조건 하에서, 예열기에 의한 순출력 향상은 약 16-26%로 계산되었다.

• 대한토목학회논문집
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• 제33권2호
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• pp.495-506
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• 2013

본 연구에서는 전단류 분산이 이송과 난류에 의한 확산의 결합에 의해 발생한다는 Taylor (1954)의 가정을 바탕으로 개념적 모형을 구성하고, 이를 3차원 개수로에 적용하여 오염물질의 혼합과정을 재현할 수 있는 시간분리 혼합모형(Time-split Mixing Model; TMM)을 개발하였다. 개발된 모형은 연산자 분리 기법(operator split method)과 유사하게 혼합과정을 종방향 혼합과 횡방향 혼합으로 분리하고, 유속 연직편차에 의한 농도분리과정과 난류확산에 의한 연직방향 혼합과정을 순차적으로 반복 계산함으로써 2차원 이송-분산을 재현한다. 수치모의 결과, 제안된 모형은 수로벽면에 의한 농도중첩 효과를 잘 반영하고 있으며, Taylor 구간 내에서 2차원 이송-분산 모형의 해석해와 거의 일치하고 있음을 확인하였다(Chatwin, 1970). 본 모형은 하상경사, 하폭 대 수심 비, 혼합시간 등의 변화에 따라 분산 정도를 달리 재현하고 있으며, 산정된 종분산계수는 Elder(1959)가 제안한 상수값과는 달리 혼합시간에 따라 변화하는 양상을 나타냈다. 횡분산계수의 경우, Sayre와 Chang(1968), Fischer 등(1979)이 실험을 통해 제시한 값과 유사한 범위를 나타냈다.

• Journal of the Korean Data and Information Science Society
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• 제16권2호
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• pp.195-205
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• 2005

In decision tree analysis, C4.5 and CART algorithm have some problems of computational complexity and bias on variable selection. But QUEST algorithm solves these problems by dividing the step of variable selection and split point selection. When input variables are continuous, QUEST algorithm uses ANOVA F-test under the assumption of normality and homogeneity of variances. In this paper, we investigate the influence of violation of normality assumption and effect of the transformation of variables in the QUEST algorithm. In the simulation study, we obtained the empirical powers of variable selection and the empirical bias of variable selection after transformation of variables having various type of underlying distributions.

• 전기학회논문지
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• 제61권12호
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• pp.1872-1876
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• 2012

A calculation method of the breakdown voltage for the drain region with the cylindrical structure in LDMOS is proposed. The depletion region of the drain is divided into many smaller regions and the doping concentration of each split region is assumed to be uniformly distributed. The field and potential in each split region is calculated by the integration of the Poisson equation and the ionization integral method is used to compute the breakdown voltage. The breakdown voltage resulted from the proposed method shows the maximum relative error of 2.2% compared with the result of the 2-dimensional device simulation using BANDIS.

• 전기학회논문지
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• 제59권2호
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• pp.355-358
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• 2010

As CMOS technology continues to scale down, signal processing is favorably done in the digital domain, which requires Analog-to-Digital (A/D) Converter to be integrated on-chip. This paper presents a design methodology of 12-bit 1-MS/s Rail-to-Rail fully differential SAR ADC using Deep N-well Switch based on binary search algorithm. Proposed A/D Converter has the following architecture and techniques. Firstly, chip size and power consumption is reduced due to split capacitor array architecture and charge recycling method. Secondly, fully differential architecture is used to reduce noise between the digital part and converters. Finally, to reduce the mismatch effect and noise error, the circuit is designed to be available for Rail-to-Rail input range using simple Deep N-well switch. The A/D Converter fabricated in a TSMC 0.18um 1P6M CMOS technology and has a Signal-to-Noise-and-Distortion-Ratio(SNDR) of 69 dB and Free-Dynamic-Range (SFDR) of 73 dB. The occupied active area is $0.6mm^2$.

• 융합보안논문지
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• 제18권1호
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• pp.13-18
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• 2018

암호시스템에서 효율성은 매우 중요한 요소 중의 하나이다. 천정희 외 3인은 이산대수 문제에 기반하는 암호 시스템에서 지수승 연산 속도를 높이기 위해 새로운 지수 형태를 제안하였다. 제안된 변형은 고정된 원소 ${\alpha}$와 작은 해밍 웨이트를 가지는 두 원소 $e_1$, $e_2$에 대해 $e_1+{\alpha}e_2$로 표현되며 스플릿 지수라 불린다. 그들은 $e_1$, $e_2$를 각각 $Z_p$의 부분집합이면서 언밸런스드 부분집합인 $S_1$, $S_2$에서 선택하였다. 본 논문에서는 $S_1$, $S_2$를 $Z_p$의 부분집합이면서 밸런스드 부분집합이 되도록 하여 효율성을 개선한다. 결과적으로, 이진 유한체에서의 지수승 연산 속도는 9.1%, 코블리츠 곡선에서의 스칼라 곱셈 연산 속도는 12.1% 빨라진다.

• 동서간호학연구지
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• 제25권1호
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• pp.26-32
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• 2019

Purpose: The purpose of this methodological study was to examine the validity and reliability of a translated Korean version of Templer's death anxiety scale among older adults. Methods: The translated Korean scale was administered to 203 older people who aged over 65 years. Exploratory factor analysis was utilized to assess the factor structure of the scale. Internal consistency of the scale was determined using Cronbach's ${\alpha}$ and Guttman's split-half coefficient. Results: Factor loadings of the scale ranged from .43 to .86. The scale showed good internal consistencies of both total scale (13 items, ${\alpha}=.83$) and three sub-scales: meaning of death (6 items, ${\alpha}=.77$), death-related event (5 items, ${\alpha}=.72$), and time of death (2 items, ${\alpha}=.80$). The concurrent validity compare with Fear of Death Scale was significant. The Cronbach's alpha and Guttman's split-half coefficient were .83 and .80, respectively. Conclusion: The findings of this study demonstrate that the Korean version of Templer's death anxiety scale had satisfactory validity and reliability to measure death anxiety among Korean older people.