• Journal of Veterinary Clinics
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• v.30 no.6
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• pp.435-441
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• 2013

This retrospective study evaluated the effects of the interval from calving to first insemination (ICFI) and days open (DO) on the reproductive performance in dairy cows. In the first analysis, data from 705 cows were grouped based on the ICFI: short (30-60 days, n=217), medium (61-90 days, n=309), and long (91-150 days, n=179). The occurrence of endometritis was greater in the long group than in short and medium groups (p<0.05). The occurrence of ovarian cysts increased with increasing ICFI (p<0.05), while body condition score (BCS) during the 5 month postpartum period was lower with increasing ICFI (p<0.01). The hazard of pregnancy by 365 days in milk (DIM) was lower (hazard ratio [HR]=0.70, p<0.0001) in the long group, but higher (HR=1.41, p<0.0001) in the short group compared with the medium group. In the second analysis, data from 436 cows were grouped based on the DO: short (30-90 days, n=154), medium (91-180 days, n=183), and long (181-360 days, n=99). The occurrence of a retained placenta was greater in the long group than in the medium group (p < 0.05). Ovarian cysts occurred more frequently in medium and long groups than in the short group (p=0.08). BCS was lower in the short group compared with medium and long groups at month 1 postpartum (p<0.05). Milk yield (kg/day) was greater in the medium group compared with the short group at months 2 to 5 postpartum (p<0.05). The hazard of first insemination by 150 DIM was lower in the long group than in the short group (HR=0.73; p<0.02). The hazard of pregnancy by 365 DIM was lower (HR=0.64, p<0.0001) in the long group than in the medium group, while the hazard did not differ between short and medium groups (p>0.05). Moreover, the culling rate was greater in the long group than in the short group (p<0.05). In conclusion, a longer ICFI and DO resulted in reduced reproductive performance in dairy cows, which was attributable to an increase in postpartum diseases, a lower BCS and a greater milk yield.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6A
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• pp.449-456
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• 2011

Spacing factor proposed by Power is a concept of averaging air void spacing composed of geometric models. Thus, there's a limitation on simulating actual air void characteristics in concrete. This study presents SDI(spacing distribution index) to overcome the limitation of spacing factor. SDI is also evaluated through comparing SDI with SF(spacing factor). In this study, it was confirmed that SF decreased due to increasing air-entrainer content but SDI increased. This occurs because SDI is the area of spacing distribution curve and SDI increases with increasing the frequency of spacing. SDI is evaluated to have better coverage below $300{\mu}m$ of SF so that determination of critical point of SDI above 80% of durability index can be easily obtained with more reliability. SDI is the area of spacing distribution curve and reflects actual air void characteristics in concrete. A comparative study of SDI and results of freeze-thaw test will be performed later.

• Journal of Broadcast Engineering
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• v.3 no.2
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• pp.146-154
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• 1998

시간적 표본화를 채택한 다중경로방법에 의한 장면전환 검출방법은 전 동영상에 대해 매 프레임마다 순차적으로 검색하는 방법에 비해서 빠르며, 동일한 정확성을 갖고 있다. 그러나, 검출 시간을 최소화하기 위한 적절한 검출 간격을 선택하는 어떠한 기준이나 방법도 제시되지 않았으며 검출 간격을 경험에 의해 선택할 수밖에 없다. 이 논문에서는 장면 전환 검출 시간, 검출 간격과 실제 장면 전환 간격으로부터 검출 시간을 최소화하는 최적 검출 간격을 얻을 수 있음을 보였다. 평균 장면 전환 간격이 알려져 있지 않은 동영상에 대해서 최적 검출 간격을 추정할 수 있는 알고리듬을 제안하였다.

• Journal of Korean Society of Transportation
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• v.30 no.2
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• pp.93-100
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• 2012

This study dealt with the critical gap of roundabouts in Korea. The objective was to develop a model to derive critical gaps by analyzing gap acceptance patterns. In this context, the present study had a particular emphasis on collecting the data for accepted or rejected gaps. The main contributions of the study were as follows. First, accepted or rejected gaps were counted and measured through video frame analysis on the traffic patterns of 20 roundabouts in Korea. Based on the data, a gap acceptance model, guaranteeing the statistical significant in their parameters, was developed in the framework of the Logit model. Second, the critical gap calculated from the developed model was evaluated to be 2.584 seconds as a whole. Also, the critical gap in urban areas was estimated to be 2.744 seconds, whilst the critical gap in rural areas was estimated to be 2.416 seconds. Finally, critical gaps of roundabout in Korea were found to be smaller than those in foreign countries by about 1.5~2.5 seconds.

• Proceedings of the KIEE Conference
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• 2004.05b
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• pp.140-147
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• 2004

등간격 접지Grid의 설계에서는 대부분의 전류가 외곽접지도체로 누설되어 Grid 구석 접촉전압이 중심 접촉전압 보다 높아지는 문제점이 있다. 비등간격 접지Grid의 설계는 이러한 문제점을 극복할 수 있으나 적절한 비등간격 접지Grid의 설계방법이나 간격결정 방법은 논의되고 있지 않다. 따라서, 본 논문에서는 비등간격 접지Grid의 장점, 수식, 최적의 간격비율을 제시한다.

• Korean Journal of Cognitive Science
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• v.16 no.4
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• pp.255-270
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• 2005

Memory for repeated items is better if they are repeated in a spaced than in a massed fashion (Sparing effect). To investigate the neural mechanisms of sparing effect and successful encoding, lags of repetition were manipulated at encoding stage in an event-related MU study. The behavioral data showed typical spacing effect on recognition judgment, and greater activity for items that were repeated in a spaced fashion than for items that were repeated in a massed fashion has been observed in dorsolateral frontal cortex(DLFC) and ventrolateral frontal cortex(VLFC) of left hemisphere. These conical regions also showed greater activity for novel items than for items that were repeated in a massed fashion. These findings suggest that sparing effect and its relevant successful encoding are attributed to higher level of attentional control and semantic processing.

• Journal of Korean Society of Transportation
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• v.18 no.6
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• pp.19-32
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• 2000

우리나라 비신호 교차로의 운영방법은 미국과는 다르게 대부분 완전 비제어식 운영(Totally Uncontrol)방법으로 되어있다. 본 연구에서는 우리나라 비신호 교차로들 중 미국 HCM의 TWSC 교차로에 관한 분석방법이 적용 가능하다고 판단되는 비신호 교차로들을 대상으로 임계간격과 추종시간의 기준을 분석하였다. 본 연구에서는 수도권을 중심으로 총 11개의 4-지 비신호 교차로들을 대상으로 이동류별, 차량의 종류별에 따른 차량들의 임계간격과 추종시간을 조사 및 분석하였다. 그 결과 임계간격은 3.8초 - 5.4 초로 나타났으며, 추종시간은 2.4초- 2.7초 범위를 나타내었다. 또한, 임계간격의 경우 차량의 종류별에 따른 차이는 나타나지 않았으나, 이동류별로는 차이를 나타내었다. 이에 반하여, 추종시간은 이동류별에 따른 차이가 없으며, 차량의 종류별에 따라 차이가 존재하는 것으로 분석되었다. 본 연구의 분석 결과인 임계간격과 추종시간의 기준치를 국외 나라들의 연구결과와 비교 분석한 결과는 국외보다 낮게 분석되었으며, 이는 우리나라와 국외의 운전자 운전특성과 비신호 교차로의 운영방식의 차이에서 나타난 결과로 판단된다. 본 연구에서 제안한 임계간격과 추종시간의 기준은 수도권 지역의 4-지 비신호 교차로들 중 주도로와 부도로의 교통량과 속도 등의 현저한 차이가 있는 교차로 분석시 이 기준으로 적용할 수 있고, 우리 나라의 TWSC 방법을 갖는 비신호 교차로에 관한 용량과 지체시간의 이론적 모형 개발과 용량 및 지체시간의 분석을 위한 기초 자료로 활용할 수 있을 것으로 판단된다.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06c
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• pp.483-486
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• 1998

한국해양연구소 온누리호에 장착된 에어건 배열에서 건 간격에 따른 빔 패턴 변화를 확인하였으며 남극해역에서 획득된 탐사자료와 비교하였다. 컴퓨터 모의과정과 배열 이론을 이용하여 신호진폭 및 빔 폭 변화 등을 시간 및 주파수 영역에서 분석하였다. 154 Hz에서 송이배열 (cluster array) 및 폭 배열 (wide array)의 빔 폭 변화는 배열 형태보다는 건 간격에 큰 영향을 받고 있어 배열 형태가 달라도 빔 폭은 서로 유사하게 변한다. 건 간격이 클수록 송이배열이 90$^{\circ}$의 빔 패턴에서 주엽 (mainlobe)이 최대치가 되는 것과는 달리 폭배열은 0$^{\circ}$에서 최대치를 나타내며 부엽 (sidelobe)은 건 간격과 무관하게 나타난다. 두 배열의 선형간섭이 점차 줄어드는 건 간격은 2.43 m이다. 남극해 탐사자료는 건 간격이 증가함에 따라 주신호 진폭은 약하게 기포는 강하게 증가한다. 이러한 결과는 빔 패턴 변화에서도 마찬가지로 나타나는데 건 간격이 클수록 주엽의 빔 폭이 점차 좁아져 강한 빔 패턴을 나타냄으로서 남극 탐사자료와 서로 잘 일치한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.5
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• pp.116-124
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• 2006

No matter how the equally spaced grounding grid is designed there are many problem. The best-fitted design for unequally spaced grounding grid is a part that must be considered. This paper Suggest a new way of calculation for grounding grid space of ground conductor by an algebraic function control(The first-order function, Root function, Polynomial function etc.) and on the optimal spaced grounding conductor that make the under 2[%] between maximum potential and minimum potential.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.8 no.1
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• pp.69-81
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• 1970

1. Four soybean varieties in pure stand and mixtures were grown in 20 competition treatments of genotypes at within-row spacings of 5, 10, 20, 40, and 80 cm and were investigated in 10 characters for different genotypes. 2. Yield, weight of 100 seeds, height, number of branches, pods per plant, and seeds per pod were highly significant for within-row spacing treatment. 3. There was no spacing treatment effect for number of nodes and days to flower. Maturity did not respond equally in four varieties for spacing effect. 4. Fruiting period was influenced by spacing treatment. Height and number of branches were increased as within-row spacings were increased. Seed yield per area was increased oppositely. 5. Difference between fertilizing and non-fertilizing treatment was not significant in this experiment. At 80 cm spacing no competition effect occurred for yield. 6. In the competition effect, Kumkang Daerip was strong competitor ani Chungbuck Back and Shelby were weak competitors. 7. The within-row spacing of uniformity in roder to increase yield per area was proved as 20 cm in this study. 8. Oil percent was increased as spacings were increased and protein percent was as spacings were decreased.