• 한국산림과학회지
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• 제97권2호
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• pp.135-139
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• 2008

Seed production and germination could be influenced by some factors. The picking time and climate factors are regarded as the elements to obtain sound seeds. We have observed the seed productivity and germination of seeds from trees of Chamaecyparis obtusa selected in a clonal seed orchard. Depending on picking time, various shapes from liquid material, something jellied to the fully matured one were observed. Germination aspects varied throughout the test days. After 20days of seeding in a glass petri-dish, germinal apparatuses appeared from the all seeds which had been picked from after at the end of August. The highest germination rate of about 30% was observed from the seeds picked from $20^{th}$ of September and $10^{th}$ of October. Seed production was about two times higher in 2005 than in 2006 and the average germination rate was also higher in 2005. We have also analyzed the effects of climatic factors about two consecutive years on seed productivity. Among the climatic factors, monthly sum of temperature and of precipitation were the main factors for maturation of Chamaecyparis obtusa seeds.

• Journal of Positioning, Navigation, and Timing
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• 제3권3호
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• pp.107-116
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• 2014

When an incoming Global Positioning System (GPS) signal is acquired, pull-in search performs a finer search of the Doppler frequency of the incoming signal so that phase lock loop can be quickly stabilized and the receiver can produce an accurate pseudo-range measurement. However, increasing the accuracy of the Doppler frequency estimation often involves a higher computational cost for weaker GPS signals, which delays the position fix. In this paper, we show that the Doppler frequency detectable by a long coherent auto-correlation can be accurately estimated using a complex-weighted sum of consecutive short coherent auto-correlation outputs with a different Doppler frequency hypothesis, and by exploiting this we propose a noise resistant, low-cost and highly accurate Doppler frequency and phase estimation technique based on a reverse directional application of the finite rate of innovation (FRI) technique. We provide a performance and computational complexity analysis to show the feasibility of the proposed technique and compare the performance to conventional techniques using numerous Monte Carlo simulations.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제26권4호
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• pp.257-275
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• 2023

본 연구는 초등학교 5학년 학생들을 대상으로 수학적 논증을 강조한 수업을 설계 및 구현하여 수업의 실제를 분석하였다. 문헌 연구를 통해 수학적 논증을 강조한 수업을 1) 패턴 주목하기, 2) 추측 분명히 나타내기, 3) 시각적 모델로 표현하기, 4) 표현에 근거한 논증하기, 5) 비교 및 대조하기 5단계로 구성한 다음, 연속된 홀수의 합은 제곱수임을 주제로 수업을 설계하였다. 그리고 실제 수업 과정에서 수학적 논증을 강조한 수업이 어떻게 구현되는지 수업의 흐름을 단계별로 분석하였다. 본 연구의 결과를 바탕으로 초등학교에서 수학적 논증을 강조한 수업의 시사점을 논의하였다.

• 한국해양학회지:바다
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• 제16권4호
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• pp.223-237
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• 2011

하구둑으로 인해 담수의 공급이 간헐적으로 발생하는 영산강 하구에서는 담수의 방류가 하구의 유동패턴, 염분농도의 변이, 영양염 공급 등 하구환경과 생태계 반응을 주도하는 요인이다. 담수의 방류는 유역의 강우조건에 영향을 받으므로 담수의 방류시기 및 규모를 파악하기 위해서는 담수방류를 유발하는 강우조건과 강우-방류간 상관관계에 대한 이해가 필요하다. 또한 담수방류가 하구에 미치는 영향을 평가하기 위해서는 방류의 규모와 더불어 빈도에 대한 고려가 필수적이다. 이 연구는 영산강 하구역의 담수방류를 예측하고 평가하는 도구로서 영산강 하구둑의 담수 방류자료를 대상으로 강우에 보다 직접적으로 반응하는 극치방류의 확률분포함수를 파악하고 극치방류를 유발하는 강우조건을 판별하여 극치방류를 유발하는 강우와 극치방류 간의 빈도-규모 관계식을 도출하는 데 목적을 두었다. 13.7년(1997.1.1-2010.8.31)간의 일방류량 자료에 대하여 일연속방류를 분석의 기본단위인 방류이벤트로 정의하되 4일 이상의 일연속방류의 경우는 방류패턴에 토대를 둔 이벤트 분리 알고리듬을 적용하여 개별 이벤트를 식별하였다. 총 529건의 방류 이벤트에 대하여 14년간의 연 최고치 중 최솟값에 해당하는 133,656,000 $m^3$을 기준으로 극치방류이벤트를 선별하고 부분시계열 빈도분석법을 적용하여 극치방류의 확률분포함수가 Weibull(k=1.4)함수를 따름을 확인하였다. 극치방류를 기준으로 대비되는 강우 l일전 3일합 강우량이며 최솟값은 50.98 mm인 것으로 나타났다. 이 기준에 따라 추출된 방류유발기능 강우군은 총 102건으로 극치방류이벤트의 수보다 많았다. 정준판별분석을 통해 3일합 강우량 이외에 관리수위대비(-1.35 m EL.) 하구호 수위가 방류유발 강우를 규정하는 중요한 요소라는 점과 방류유발가능 강우군을 선별하는 임계값을 104mm로 재조정할 경우 3일합 강우량만으로 방류유발 강우를 규정할 수 있음을 확인하였다. 극치방류 유발 강우만을 대상으로 강우-방류 관계식을 수립한 결과 3일합-강우량($\overline{r_{3day}}$), 3일합-강우량 재현주기($T_{r3}$), 방류량(Discharge, D), 방류량 재현주기($T_d$)의 관계는 $D=1.111{\times}10^8+1.677{\times}10^6{\overline{r_{3day}}$, (${\overline{r_{3day}}{\geqq}104$), $T_d=1.326T^{0.683}_{r3}$, $T_d=0.117{\exp}[0.0155{\overline{r_{3day}}]$로 나타났다. 100년 주기 3일합 강우(357mm)에 의해 유발되는 방류량은 영산강 하구둑 방류량의 재현주기는 30.8년 정도이며 그 양은 $7.0979{\times}10^8m^3$이다. 담수방류의 재현주기 및 재현주기에 기초한 강우-방류 관계식은 영산강 하구역을 비롯하여 인위적으로 담수의 방류가 조절되는 하구역에서 담수의 영향을 평가하고 예측하는 데 기여할 수 있을 것이다.

• 대한핵의학회지
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• 제31권3호
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• pp.330-338
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• 1997

기저와 부하 뇌관류 SPECT를 순차적으로 촬영하여 2차영상에서 1차영상을 감산하여 부하 영상을 얻으면 신호가 줄어들고 잡음은 더해지므로 영상의 질이 나빠졌다. 촬영시간과 주사량에 대해 비례적인 계수와 촬영행위와 상관있는 배후방사능을 고려하여 기저영상과 감산영상의 신호 잡음 비가 최대가 되도록 하는 주사량과 촬영시간의 짝을 찾았다. 순차 촬영 시간을 30분으로 하고 주사총량이 1850MBq(50mCi)이며 아세타졸아미드의 부하에 의해 뇌의 주사량대비 섭취가 1.2배일 때 기저영상과 감산영상의 신호 잡음 비가 최대인 조건은 1차 주사량/촬영시간이 15mCi/17분, 2차 주사량/촬영시간이 35mCi/13분이었다.

• 한국정보통신학회논문지
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• 제12권10호
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• pp.1845-1852
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• 2008

인터 예측의 핵심 요소는 ME와 MC이다. ME는 SAD(Sum of Absolute Difference)와 같은 정합기준을 사용하는 것뿐만 아니라 비트스트림의 최종 비트수에 따라서 최적의 움직임 벡터를 찾는다. 인터 예측부호화는 고화질의 실시간 비디오 응용에 있어서 언제나 주된 병목을 초래한다. 따라서 실시간 비디오 응용에서는 인터 예측을 수행하는 고속의 전용 하드웨어를 필요로 한다. 본 논문에서는 H.264/AVC의 움직임 추정기를 연구하였다. 설계된 움직임 추정기는 2-D 시스토릭 배열 기반으로 기본 처리기 요소를 병렬로 연결하여 SAD 값을 빠르게 계산한다. 참조데이터를 상위영역과 하위영역으로 나누어 각각의 연결선을 두고 입력 시퀀스를 조절하여 파이프라인 중지 없이 연속적인 연산을 수행한다. 데이터 재사용 기법을 통하여 메모리 엑세스를 줄였고 특별한 지연 없이 최소의 SAD를 갖는 파티션을 찾아내어 움직임 벡터를 생성하게 하였다. 설계된 움직임 추정기는 가변 블록 크기를 지원하며 하나의 매크로블록의 연산을 하는데 328 사이클이 소요된다. 논문 [6]이 로컬메모리를 사용하는 것과 달리, 본 논문은 로컬메모리를 사용하지 않는다.

• Journal of Chest Surgery
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• 제27권12호
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• pp.1008-1014
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• 1994

Increased interest in alternative approach to thoractomy has developed because of the considerable morbidity associated with the standard posterolateral thoracotomy[ST]. Muscle sparing thoracotomy is appeared as excellent alternative because of less postoperative pain and morbidity than standard posterolateral one. Vertical axillary muscle sparing thoracotomy[VM] is the newly revised modified muscle sparing thoracotomy that overcomes the disadvantages of previous lateral muscle sparing thoracotomy such as seroma, cosmetic problems, and need of subcutaneous drains. We conducted a prospective study of 45 consecutive patients to compare postoperative pain, muscle strength of serratus anterior and latissimus dorsi, and range of motion of the shoulder girdle between ST and VM group. There were no difference in preoperative status, surgical procedure, morbidity, mortality and hospital stay between two groups. But there were significant less postoperative narcotics requirements, more preserved latissimus dorsi and serratus anterior muscle strength, nd larger range of motion of shoulder girdle [ especially flexion and internal rotation in VM group. The opening time was prolonged[p<0.01] but closing time was less in VM group [p<0.01]. The sum of opening and closing time was not different in two group. The length of incision line was shorter in VM group. The vertical skin incision was concealed by the upper arm.In conclusion vertical axillary muscle sparing thoracotomy is good alternative for various intrathoracic procedures with less postoperative pain, well preserved muscle strength,increased range of motion of the shoulder girdle and impressive cosmetic outcome.

• 대한두개안면성형외과학회지
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• 제23권3호
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• pp.103-110
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• 2022

Background: The primary objectives of mandibular surgery are to achieve optimal occlusion, low sensory disturbance, and adequate fixation with early movement. In-depth knowledge of the mandibular structure is required to achieve these goals. This study used computed tomography (CT) to evaluate the mandibular cortical thickness and cancellous space according to age and sex. Methods: We enrolled 230 consecutive patients, aged 20 to 50 years, who underwent CT scanning. The cortex and cancellous space centered around the inferior alveolar nerve (IAN) canal were measured at two specific locations: the lingula and second molar region. Statistical analysis of differences according to increasing age and sex was performed. Results: The t-test revealed that the cancellous space and cortical thickness differed significantly with respect to the threshold of 35 years of age. Both cortical thickness and cancellous space in the molar region were negatively correlated with age. Meanwhile, both cortical thickness and cancellous space in the lingula region showed a positive correlation with age. With respect to sex, significant differences in the cancellous space at the molar region and the cortical thickness at the lingula were observed. However, no further statistically significant differences were observed in other variables with respect to sex. The sum of each measurement on the mandibular body reflected the safe distance from the surface of the outer cortex to the IAN canal. The safe distances also showed statistically significant differences between those above and below 35 years of age. Conclusion: Knowledge of the anatomical structure of the mandible and of changes in bone structure is crucial to ensure optimal surgical outcomes and avoid damage to the IAN. CT examination is useful to identify changes in the bone structure, and these should be taken into account in the planning of surgery for older patients.

• 대한건축학회논문집:계획계
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• 제34권3호
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• pp.61-72
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• 2018

This study pursued to obtain 3 consecutive purposes. First, a conceptual model for comparing 3 constructivist teaching and learning strategies( problem-based learning[$P_bBL$], case-based learning[CBL] and project-based learning[$P_jBL$]) was developed. Relationships of these constructivist strategies with the development of expertise for learners were discussed. Second, specific differences between $P_bBL$, CBL and $P_jBL$ as applied in architectural design courses were analyzed under each of the teaching and learning category. Some analytical indexes were developed by content analysis, which are applicable effectively to reveal the differences. Based on the previous findings, third, a set of strategic guidelines for use in class were made and suggested in order to develop and improve expertise in architectural design. These guidelines were largely targeted for university design courses as well as education or reeducation of practicing architects. Expecially, combined application of $P_bBL$, CBL and $P_jBL$ was hypothesized and suggested as class management guidelines. In sum, a variety of $P_bBL$ problems, CBL cases and $P_jBL$ projects should be developed for expecting audience based on design subjects and tasks. As working domains of practicing architects, exploring/analyzing, understanding/making applications, and criticizing/self-reflecting should be considered in the development process.

• 한국식생활문화학회지
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• 제29권2호
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• pp.212-221
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• 2014

Korean style DASH (Dietary Approaches to Stop Hypertension) and a dietary education program for sodium reduction were developed. Reduced sodium diets (15 and 30% reductions) were developed from general diets for 3 consecutive weeks from Monday through Saturday. Subjects (19 total) were classified into two groups according to dietary education. Experimental period was from June 24 to July 23, 2012. Total sum of adaptation scores for low sodium diets significantly increased in the group that underwent dietary education compared to that without (p<0.05). After the experiment, both groups showed significantly increased values in terms of food group balance, sodium-related nutrition knowledge, attitude, and practice by paired t-test. Especially, group that underwent dietary education showed significantly higher values for attitudes by ANCOVA pre-test as a variation (p<0.01). For the results of the nutrient intake survey, group that underwent dietary education showed significantly increased values for dietary fiber (p<0.01), vitamin A (p<0.001), vitamin K (p<0.001), vitamin C (p<0.01), Folic acid (p<0.001), vitamin B12 (p<0.01), calcium (p<0.01), iron (p<0.05), and zinc (p<0.05) and significantly decreased values for sodium (p<0.05) and chloride (p<0.005). Subjects adapted to reduced sodium diets showed apparent improvements in sodium-related knowledge, attitude, practice and intake of nutrient, and these improvements were even higher in the group that underwent dietary education compared to that without. Thus, adaptation to low sodium diet combined with dietary education can improve dietary habits.