• 한국해양학회지:바다
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• 제13권4호
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• pp.342-347
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• 2008

큰수지맨드라미의 사망률과 성장률에 관한 연구를 제주도 문섬에서 2003년 2월부터 2004년 10월까지 진행하였다. 수심 15 m에 서식하는 큰수지맨드라미 48개체를 형광 플래깅 테이프로 표시했으며, 이들을 1년 6개월 동안 약2개월 간격으로 모니터링 하였다. 연구기간동안 2개월 단위의 평균 사망률은 50.4%로 나타났으며, 여름 태풍 발생시점인 2003년 8-10월에는 84.6%로 최대치를 나타내었다. 개체크기에 따른 사망률 양상에서는 등급 I(${\leq}$10 cm) 개체들의 사망률이 등급 II(10 cm-20 cm)와 등급 III(>20 cm)보다 높게 나타났다. 각 계절에 따른 성장률의 차이가 뚜렷하게 나타나지는 않았으나 가을-겨울시기의 길이 성장률이 다른 시기보다 상대적으로 높게 나타났다. 전체 조사기간 동안의 평균 길이성장률은 2개월 동안 3 cm씩 성장하는 것으로 확인 되었으며, 2003년 8-10월에는 6.4 cm로 최대치를 보였다. 한편 직경의 성장은 2개월 동안 평균 0.3 cm가 증가하였으며, 2004년 4-6월에 1.4 cm로 최대치를 나타내었다. 제주도의 큰수지맨드라미 개체군은 매년 여름 태풍에 큰 영향을 받아 높은 사망률을 보이지만, 이후 어린개체들의 높은 가입률과 빠른 성장을 통하여 개체군을 유지하는 것으로 연구되었다.

• Fisheries and Aquatic Sciences
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• 제21권11호
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• pp.34.1-34.13
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• 2018

Sexual maturity ($L_{50}$), the length at which 50% of fish in a size class are mature, is a key aspect of domestication of new fish species because it guides the procedure for identification of appropriate broodstock size for artificial spawning. In this study, the $L_{50}$ was determined for 1083 Barbus altianalis samples obtained from Lake Edward and the Upper Victoria Nile. Gonads of freshly killed samples were examined macroscopically and verified with standard histological procedures for the maturation stages that were used to determine $L_{50}$. Oocytes and spermatogenic cell sizes were compared for fish obtained from both water bodies. Results indicated that there were no variations in macro gonad features observed for fish from Lake Edward and Upper Victoria Nile. Similarly, there were no significant differences in oocyte sizes (P > 0.05) between the two populations but significant differences in spermatogenic cell sizes were noted (P < 0.05) except for spermatozoa (P > 0.05). This however did not suggest peculiar differences between the two populations for staging the gonads. Consequently, no staging variations were suggested for both populations in determination of $L_{50}$. Sexual maturity was found in the same class size of fork length (FL) 20-24.9 cm and 35-39.9 cm for males and females from both water bodies, respectively. At this FL, however, males were too small, and for good selection of vigor broodstocks for spawning and conservation purposes, they are better picked from class size of 30-34.9 cm FL and above. These findings were crucial for integration of appropriate breeding size in spawning protocol by farmers and fisheries scientists conserving wild B. altianalis populations.

• JSTS:Journal of Semiconductor Technology and Science
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• 제7권4호
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• pp.274-280
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• 2007

This paper demonstrates an efficiency improvement of the class E power amplifier (PA) by tuning-out the input capacitance ($C_{IN}$) of the power HBT with a shunt inductance. In order to obtain high output power, the PA needs the large emitter size of a transistor. The larger the emitter size, the higher the parasitic capacitance. The parasitic $C_{IN}$ affects the distortion of the voltage signal at the base node and changes the duty cycle to decrease the PA's efficiency. Adopting the L-C resonance, we obtain a remarkable efficiency improvement of as much as 7%. This PA exhibits output power of 29 dBm and collector efficiency of 71% at 1.9 GHz.

• 헤리티지:역사와 과학
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• 제47권3호
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• pp.60-85
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• 2014

본 연구의 목적은 경주지역 목곽묘 축조집단의 위계분석을 통한 사회적 신분구조를 파악하는데 있다. 경주지역 목곽묘의 위계는 목곽묘 면적과 부장된 유물의 구성에 따라 다음과 같이 분류된다. 상형토기, 갑주 등이 매납되고 목곽의 면적이 $15.0m^2$ 이상인 '가'등급에서 토기류만 매납되고 목곽의 면적이 $4.9m^2$ 이하인 '차' 등급까지 총 10등급의 구조로 구성된다. 이러한 위계구조는 각 등급이 축조할 수 있는 목곽의 규모나 매납품의 종류와 재질, 수량에 있어서 일정한 제한이 있었음을 알 수 있다. 다시 말해 고분의 내 외적 규모나 구조 그리고 매납품의 수량 종류 재질 등의 내용은 피장자의 출생 신분과 생시의 사회적 신분(지위) 등에 따라 차등을 주는 엄격한 사회적 규제가 적용되었다는 것을 뜻한다. 이러한 위계등급을 신라(사로) 신분 사회에 실질적으로 적용해 보면 '가'등급은 목곽의 규모나 매납 유물의 종류와 재질 등으로 볼 때 신라(사로)를 대표하는 최상위 지배층으로 추정된다. 그리고 '나', '다'등급은 상위 지배층, '라', '마'등급은 중위 지배층, '바', '사'등급은 하위 지배층으로 추정된다. 또한 '아', '자'등급은 상위 일반민, '차'등급은 하위 일반민의 신분(평민)으로 상정해 볼 수 있다. 이와 같이 본다면 '가'~'사'등급이 신라(사로)사회를 이끌어가는 실질적인 지배계층이라고 할 수 있다.

• 패션비즈니스
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• 제8권1호
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• pp.133-140
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• 2004

In order to compare the pattern sizes of toddlers' brands, the apparel size #95 and #100, #110 were surveyed, while upper body lengths, bust circumferences and waists, hip circumferences, shoulder length, sleeve length, neck circumferences of toddlers' underwears were examined. As a result, it was found that upper body lengths, chest circumferences and lower body lengths of toddlers' underwears differed more or by $2.0cm{\sim}3.0cm$ among brands than other sizes. In case of underwear size #95, the average upper body length was 32.8cm; the upper body size of "c" brand was longest or 33.5cm, while that of "e" brand was shortest or 32.0cm. In case of size #80, the average upper body length was 36.0cm; the upper body size of "a" brand was longest or 37.0cm, while that of "e" brand was shortest of 35.0cm. Such findings may be attributable to the fact that the main customers of "a" and "b" brands whose pattern sizes are larger are middle or lower class people who tend to buy larger toddlers' apparels than their children's actual body sizes. In contrast, "e" brand seems to target the upper class who prefers the apparels almost fitting their children's actual body sizes.

• 패션비즈니스
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• 제7권5호
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• pp.101-107
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• 2003

In order to compare the sizes of infants;brands, the apparel size #70 and #80, #90 were surveyed, while upper body lengths, bust circumferences and waists, hip circumferences, shoulder length, sleeve length, neck circumferences of infants' underwears were examined. As a result, it was found that upper body lengths, chest circumferences and lower body lengths of infants' underwears differed more or by $2.0{\sim}3.0cm$ among brands than other sizes. In case of underwear size #70, the average upper body length was 32.8cm; the upper body size of "c" brand was longest or 33.5cm, while that of "e" brand was shortest or 32.0cm. In case of size #80, the average upper body length was 36.0cm; the upper body size of "a" brand was longest or 37.0cm, while that of "e" brand was shortest of 35.0cm. Such findings may be attributable to the fact that the main customers of "a" and "b" brands whose pattern sizes are larger are middle or lower class people who tend to buy larger infants' apparels than their children's actual body sizes. In contrast, "e" brand seems to target the upper class who prefers the apparels almost fitting their children's actual body sizes.

• 한국산림과학회지
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• 제99권5호
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• pp.720-725
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• 2010

On the basis of vegetation data in the 9.12 ha (380 m ${\times}$ 240 m) permanent sample plot of the spruce-fir valley forest in Liangshui National Reserve of Xiaoxing'an Mountains, the study was conducted to evaluate spatial distribution pattern and spatial association by using point pattern analysis for living and dead trees of Larix gmelini by DBH size class. The number of L. gmelini were counted as 59 living stems/ha (6.42 $m^2$/ha of basal area) and 34 dead stems/ha (2.86 $m^2$/ha of basal area). The distributional curve of diameter class exhibited bimodal shape. The analysis of spatial distribution patterns of all living larch stems noted the clumped distribution on the whole. The size of larch aggregates of dead stems was decreased as diameter class was increased. The distribution of dead stems became gradually randomized with decreased clumped size as the scale increased. Living stems and dead stems of the larch had positive spatial association at most of scales, illustrating that the occurrence of mortality of the larch tree was closely related to the distribution pattern of living larch trees.

• 한국정보통신학회논문지
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• 제13권12호
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• pp.2541-2546
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• 2009

EPCglobal Class-1 Gen-2 충돌방지 기법에서는 Q-알고리즘을 통하여 질의 라운드의 프레임 크기를 결정한다. Q-알고리즘은 리더의 식별영역 내에 있는 태그의 수를 추정하지 않고 슬롯의 상태만을 이용하여 질의 라운드의 프레임 크기를 계산하므로 다른 DFSA 알고리즘에 비하여 리더의 알고리즘이 단순한 장점이 있다. 반면, Q-알고리즘에서는 프레임 크기를 조절하기 위한 매개변수의 최적화 된 값은 정의하지 않고 있다. 따라서 본 논문에서는 시뮬레이션을 통하여 최소의 식별시간을 얻을 수 있는 최적의 매개변수 값을 제안하였다.

• Computers and Concrete
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• 제28권5호
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• pp.521-532
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• 2021

Present paper focuses on the modeling of size effect on the compressive strength of normal concrete with the application of Discrete Element Method (DEM). Test specimens with different size and shape were cast and uniaxial compressive strength test was performed on each sample. Five different concrete mixes were used, all belonging to a different normal strength concrete class (C20/25, C30/37, C35/45, C45/55, and C50/60). The numerical simulations were carried out by using the PFC 5 software, which applies rigid spheres and contacts between them to model the material. DEM modeling of size effect could be advantageous because the development of micro-cracks in the material can be observed and the failure mode can be visualized. The series of experiments were repeated with the model after calibration. The relationship of the parallel bond strength of the contacts and the laboratory compressive strength test was analyzed by aiming to determine a relation between the compressive strength and the bond strength of different sized models. An equation was derived based on Bazant's size effect law to estimate the parallel bond strength of differently sized specimens. The parameters of the equation were optimized based on measurement data using nonlinear least-squares method with SSE (sum of squared errors) objective function. The laboratory test results showed a good agreement with the literature data (compressive strength is decreasing with the increase of the size of the specimen regardless of the shape). The derived estimation models showed strong correlation with the measurement data. The results indicated that the size effect is stronger on concretes with lower strength class due to the higher level of inhomogeneity of the material. It was observed that size effect is more significant on cube specimens than on cylinder samples, which can be caused by the side ratios of the specimens and the size of the purely compressed zone. A limit value for the minimum size of DE model for cubes and cylinder was determined, above which the size effect on compressive strength can be neglected within the investigated size range. The relationship of model size (particle number) and computational time was analyzed and a method to decrease the computational time (number of iterations) of material genesis is proposed.

• 한국지열·수열에너지학회논문집
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• 제14권2호
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• pp.1-7
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• 2018

The purpose of this study was to analyze the energy consumption of Elementary, Middle and High Schools in Daejeon Metropolitan City. The main results are as follow: 1) Annual energy consumption per class was 12,825 (kWh/class) at elementary schools, 15,780 (kWh/class) at middle schools, and 29,447 (kWh/class) at high schools, 2) Generally the smaller the size of the school, the higher the energy consumption per class. However according to the HVAC system there was no consistent pattern of energy consumption per class. 3) According to Box and Whisker's Chart, distribution of energy consumption of elementary and middle schools' had small range. However, the range of high schools increased. 4) Energy consumption in winter season was larger than that of summer season in schools.