• Current Research on Agriculture and Life Sciences
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• 제20권
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• pp.1-8
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• 2002

재배종과 야생종의 인공교잡 분리세대에서 주요형질들의 변이와 유전력을 조사하여 야생종을 이용한 콩 품종육성의 기초자료를 얻고자 수행한 결과를 요약하면 다음과 같다. 두 인공교배의 $F_2$ 집단에서 100립중을 제외한 나머지 조사 형질들은 초월분리를 보였다. $F_1$과 $F_2$의 평균 개화일수는 양친의 중간정도로 정규분포를 보였다. 백립중의 $F_1$ 평균은 은하콩, 소백나물콩 두 조합 각각 6.2, 5.7g으로 소립종 쪽으로 치우쳤으며, 입중의 분포는 소립종 쪽으로 치우친 정규분포를 보였다. $F_2$의 평균수량은 양친의 중간정도이었다. $F_1$의 덩굴성은 두 조합 각각 6.4, 6.6이었으며 $F_2$ 평균은 은하콩 조합이 6.0으로 덩굴성 쪽으로 치우쳐 덩굴성이 부분적인 우성을 보였으나, 소백나물콩 조합에서는 4.6으로 은하콩과는 다른 결과를 보였다. 경장, 개화일수, 개체당 협수, 수량, 도복, 덩굴성 등은 높은 광의의 유전력을 보였으며 100립중은 협의의 유전력이 은하콩 조합에서 52.3%, 소백나물콩 조합에서 65.6%로 평가되어 초기세대에서의 선발이 가능한 것으로 나타났다.

• KEPCO Journal on Electric Power and Energy
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• 제8권2호
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• pp.79-86
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• 2022

Recently, the amount of maintenance is increasing due to the aging of power facilities, but the budget is constrained. Therefore, the importance of asset management that selects replacement priorities based on the failure probability and enhances investment effects is increasing. Because the number of distribution transformers is very large, the proportion of investment cost is very high. Therefore, it is important to select the investment priority by evaluating the reliable remaining life based on the failure probability. This paper evaluates the statistical expected life using the failure data of distribution transformers for the last 11 years and the current operation data. The hazard rate of distribution transformer and MV cable was compared with each other and the adequacy of early failure removal was reviewed and the statistical expected life corresponding to the cumulative failure probability B3% was calculated.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권12호
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• pp.646-652
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• 2006

This study identifies the comparison of Technical specification and Characteristics of DC Protection Relay(ETCPU200) used in DC Distribution System in Korea. ETCPU200 has completed Field Test and approved its capability by finding out causes of recent operations through lately developed digital DC protection relay in parallel operation at Maebong-Substation, Sangbong-Substation, Nakseongdae-Substation, Euljirosaga-Substation, Jegi-Substation and Chongyangri T/P area. It also examines additional features for efficient System Analysis and Operations.

• 한국산학기술학회논문지
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• 제21권7호
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• pp.625-637
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• 2020

함정 무기체계는 작전운용성능(능력)에 따라 국내 기술 수준에 기반하여 설계/건조되며, 일정 기간 운용 후 성능개량 소요 발생에 따른 개조/개장 및 기존함 대비 고도화된 후속함이 요구되는 특성을 가지고 있다. 이러한 특성을 고려하고 고객이 요구하는 함정 무기체계 기술 수준과 무기체계 연구개발을 통한 국내 기술 수준 향상 및 핵심기술 확보하기 위해 기술 분류/특성이 정형화되어있는 특허 자료 분석을 통해 획득 필요 기술에 대한 의사결정 자료로 활용할 수 있다. 이를 위해 방위사업법 제35조(방산업체의 지정 등)에 따라 지정된 10개 함정 분야 방산업체의 특허자료를 특허청 특허정보검색서비스를 통해 특허자료(특허수/국제특허분류 14,964건/352개)를 수집하였으며, 수집된 자료를 기반으로 함정분야 방산업체 간 사회망 분석을 통해 중심성이 높은 58개 국제특허분류를 추출했다. 추출된 국제특허분류를 기반으로 주성분 분석을 통해 함정 분야 방산업체가 집중하는 주요 기술 분야로 국제특허분류 7개(B63B, H01M, F03D, B01D, H02K, B23K, H01H)를 확인했다. 이어서 자기회귀 결합 이동평균 모형 분석결과, 국제특허분류 3개(B63B, B01D, B23K)는 지속적인 기술획득 활동이 예측했으며, 국제특허분류 4개(H01M, F03D, H02K, H01H)는 기술획득 활동이 낮아짐을 예측했다.

• 생명과학회지
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• 제19권6호
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• pp.693-697
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• 2009

본 조사는 능동산의 산림지 2곳에 대한 목본류의 다양성 양상을 조사하기 위해 12 plot $(100{\times}100 m)$를 설정하였다. 흉고직경 10 cm 이상의 목본류 2,157 그루를 동정한 결과 총 35과 135종이었다. 최소 유의성 차이(LSD)에서 지역 A (울주군 석남사 방향)가 지역 B (밀양시 얼음골 방향)보다 높았다. Shannon-Wiener의 다양성 지수에서 지역 A는 1.822, 지역 B는 2.118로 두 지역간 유의한 차이가 있었다(F=4.12, p<0.05). 곰솔-갈참나무군락이 두 지역에서 우점 하였다. 그러나 지역 A의 중간 고도는 소나무가 우점인 반면 지역 B의 중간 고도부위는 참나무속 식물군락과 서어나무군락이 우점 하였다. 공간 분포 분석에서 능동산의 동서지역의 식물상은 서로 이질적이며 미세기후와 패치(patchy)구조를 나타내었다.

• Computers and Concrete
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• 제19권6호
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• pp.711-716
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• 2017

This paper presents a method using artificial neural networks (ANNs) to predict the residual moment capacity of thermally insulated reinforced concrete (RC) beams exposed to fire. The use of heat resistant insulation material protects concrete beams against the harmful effects of fire. If it is desired to calculate the residual moment capacity of the beams in this state, the determination of the moment capacity of thermally insulated beams exposed to fire involves several consecutive calculations, which is significantly easier when ANNs are used. Beam width, beam effective depth, fire duration, concrete compressive and steel tensile strength, steel area, thermal conductivity of insulation material can influence behavior of RC beams exposed to high temperatures. In this study, a finite difference method was used to calculate the temperature distribution in a cross section of the beam, and temperature distribution, reduction mechanical properties of concrete and reinforcing steel and moment capacity were calculated using existing relations in literature. Data was generated for 336 beams with different beam width ($b_w$), beam account height (h), fire duration (t), mechanical properties of concrete ($f_{cd}$) and reinforcing steel ($f_{yd}$), steel area ($A_s$), insulation material thermal conductivity (kinsulation). Five input parameters ($b_w$, h, $f_{cd}$, $f_{yd}$, $A_s$ and $k_{insulation}$) were used in the ANN to estimate the moment capacity ($M_r$). The trained model allowed the investigation of the effects on the moment capacity of the insulation material and the results indicated that the use of insulation materials with the smallest value of the thermal conductivities used in calculations is effective in protecting the RC beam against fire.

• 대한기계학회논문집B
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• 제25권10호
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• pp.1311-1317
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• 2001

To investigate only the effects of the stratified mixture distribution on initial flame propagation and combustion characteristics, the instantaneous equivalence ratio in the spark plug gap and combustion pressure were measured simultaneously In a constant volume chamber, To induce the stratified propane-air mixture distribution near the spark plug, counter-flow typed mixture injection system was used under the constant mean equivalence ratio $\Phi$$\_$mean/= 1.0 The instantaneous equivalence ratio was measured by a single-shot Raman scattering with narrow-band KrF excimer laser. The measuring error was within the limit of $\pm$ 3.5% provided that the proposed method was applied to the measured Raman signals. Judging from mass fraction burned derived from the measured pressure, the optimum combustion characteristics were shown under the condition that the local equivalence ratio in the spark plug was near 1.28$\pm$0.04, and these characteristics were more remarkable at the initial stage of combustion.

• 상하수도학회지
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• 제30권4호
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• pp.369-379
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• 2016

It was confirmed that the extreme value distribution model applies to probability of exceeding more than once a day monthly the facility capacities using data of daily maximum inflow rate for 7 wastewater treatment plant. The result of applying the extreme value model, A, D, E wastewater treatment plant has a problem compared to B, C, F, G wastewater treatment plant. but all the wastewater treatment plant has a problem except C, F wastewater treatment plant based 80% of facility capacity. In conclusion, if you make a standard in statistical aspects probability exceeding more than once a day monthly can be 'exceed day is less than a few times annually' or 'probability of exceeding more than once a day monthly is less than what percent'.

• ETRI Journal
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• 제43권2호
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• pp.184-196
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• 2021

The research domain of underwater communication has garnered much interest among researchers exploring underwater activities. The underwater environment differs from the terrestrial setting. Some of the main challenges in underwater communication are limited bandwidth, low data rate, propagation delay, and high bit error rate (BER). As such, this study assessed the underwater acoustic (UWA) aspect and explored the expression of error performance based on t-distribution noise. Filter orthogonal frequency-division multiplexing refers to a new waveform candidate that has been adopted in UWA, along with turbo and polar codes. The empirical outcomes demonstrated that the noise did not adhere to Gaussian distribution, whereas the simulation results revealed that the filter applied in orthogonal frequency-division multiplexing could significantly suppress out-of-band emission. Additionally, the performance of the turbo code was superior to that of the polar code by 2 dB at BER 10-3.

• Journal of the Korean Statistical Society
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• 제24권1호
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• pp.197-218
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• 1995

We first consider the random censorship model of survival analysis. Efron (1981) introduced two equivalent bootstrap methods for censored data. We propose a new bootstrap scheme, called Method 3, that acts conditionally on the censoring pattern when making inference about aspects of the unknown life-time distribution F. This article contains (a) a motivation for this refined bootstrap scheme ; (b) a proof that the bootstrapped Kaplan-Meier estimatro fo F formed by Method 3 has the same limiting distribution as the one by Efron's approach ; (c) description of and report on simulation studies assessing the small-sample performance of the Method 3 ; (d) an illustration on some Danish data. We also consider the model in which the survival times are censered by death times due to other caused and also by known fixed constants, and propose an appropriate bootstrap method for that model. This bootstrap method is a readily modified version of the Method 3.