• 자원환경지질
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• 제54권2호
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• pp.213-232
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• 2021

Ore criteria at the Sheba Deposit indicate orogenic mineralization type. Rocks and mineral assemblages suggest low formation-temperature of green-schist facies. Pyrite found in two generations; Type1 is irregular grains, contains higher arsenic and gold contents, compared to the relatively younger phase Type2 pyrite, which is composed of euhedral grains, found adjacent to late quartz-carbonate veins or at rims of type1 pyrite. Two gold generations were identified; type1 found included in sulphides (mainly pyrite). The second gold type was remobilized (secondary) into free-lodes within silicates (mainly quartz). Gold fineness is high, as gold contains up to 95 wt. % Au, Ag up to 3.5 wt. %, and traces of Cu, Ni, and Fe. Pyrite type2 contains tiny mineral domains (rich in Al, Mn, Hg, Se, Ti, V, and Cr). Zoning, and replacement textures are common, suggesting multiple mineralization stages. The distribution and relationships of trace elements in pyrite type2 indicate three formation patterns: (1) Al, Mn, Hg, Se, Ti, V, Cr, and Sn are homogeneously distributed in pyrite, reflecting a synchronous formation. (2) As, Ni, Co, Zn, and Sb display heterogeneous distribution pattern in pyrite, which may indicate post-formation existence due to other activities. (3) Au and Ag show both distribution patterns within pyrite, suggesting that gold is found both in microscopic phases and as chemically bounded phase.

• Current Research on Agriculture and Life Sciences
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• 제18권
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• pp.9-17
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• 2000

풋마름병과 역병에 복합저항성인 계통을 육성하기 위한 노력으로서 앞서 역병 저항성으로 육성한 계통(16-2-3-2 = 역병 저항성 '칼미초', 19-1-3-7-1-1, 19-2-4-5-3-2 = 역병 저항성 '수비초', 김 등, 1996)과 풋마름병 저항성 계통(KC350 = MC 4, KC353 = PBC631)을 교배하여 육성한 $F_5$와 $BC_1F_4$, $F_6$와 $BC_1F_5$ 세대에 대해 1999년과 2000년에 각각 풋마름병과 역병에 대한 복합저항성을 검정하였다. 풋마름병과 역병에 복합 저항성을 보인 개체를 선발하여 다음 세대의 종자를 채종하였다.

• 전기학회논문지
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• 제66권9호
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• pp.1309-1316
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• 2017

As penetration level of Distributed Generations (DGs) on weak distribution networks gets higher, voltage rise problem can often occur due to reverse power which is not expected in conventional distribution networks. It, however, cannot be effectively solved by using conventional voltage regulating devices such as On-Load Tap Changers (OLTCs), Step Voltage Regulators (SVRs) because those do not consider the presence of DGs when determining relevant setting parameter for voltage regulation. This paper presents a scheme for voltage regulation using coordinated control between OLTC and DGs which can actively participate in the regulation. The scheme decides which device should be operated first based on the characteristics of regulating devices, in order to prevent unnecessary operation of output changes of DG and excessive tap changing operation of OLTC. Computer simulations considering daily irradiation of PV and load curve are performed by using MATLAB Simulink and performance comparison between the presented scheme and conventional ones is also made. It can be concluded from simulation results that the scheme presented is very effective to regulate voltages in distribution networks with multiple DGs.

• Asian-Australasian Journal of Animal Sciences
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• 제24권2호
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• pp.162-172
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• 2011

In this paper, simulation was used to determine accuracies of genomic breeding values for polygenic traits associated with many thousands of markers obtained from high density genome scans. The statistical approach was based upon stochastically simulating a pedigree with a specified base population and a specified set of population parameters including the effective and noneffective marker distances and generation time. For this population, marker and quantitative trait locus (QTL) genotypes were generated using either a single linkage group or multiple linkage group model. Single nucleotide polymorphism (SNP) was simulated for an entire bovine genome (except for the sex chromosome, n = 29) including linkage and recombination. Individuals drawn from the simulated population with specified marker and QTL genotypes were randomly mated to establish appropriate levels of linkage disequilibrium for ten generations. Phenotype and genomic SNP data sets were obtained from individuals starting after two generations. Genetic prediction was accomplished by statistically modeling the genomic relationship matrix and standard BLUP methods. The effect of the number of linkage groups was also investigated to determine its influence on the accuracy of breeding values for genomic selection. When using high density scan data (0.08 cM marker distance), accuracies of breeding values on juveniles were obtained of 0.60 and 0.82, for a low heritable trait (0.10) and high heritable trait (0.50), respectively, in the single linkage group model. Estimates of 0.38 and 0.60 were obtained for the same cases in the multiple linkage group models. Unexpectedly, use of BLUP regression methods across many chromosomes was found to give rise to reduced accuracy in breeding value determination. The reasons for this remain a target for further research, but the role of Mendelian sampling may play a fundamental role in producing this effect.

• Journal of Communications and Networks
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• 제6권1호
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• pp.78-87
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• 2004

This paper presents deterministic, worst-case analysis of a queueing system whose multiple homogeneous input streams are regulated by the associated leaky buckets and the queueing system that has a single stream regulated by the jumping-window. Queueing delay averaged over all items is used for performance measure, and the worst-case input traffic and the worst-case performance are identified for both queueing systems. For the former queueing system, the analysis explores different phase relations among leaky-bucket token generations. This paper observes how the phase differences among the leaky buckets affect the worst-case queueing performance. Then, this paper relates the worst-case performance of the former queueing system with that of the latter (the single stream case, as in the aggregate streams from many users, whose item arrivals are regulated by one jumping-window). It is shown that the worst-case performance of the latter is identical to that of the former in which all leaky buckets have the same phase and have particular leaky bucket parameters.

• 한국산학기술학회논문지
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• 제21권9호
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• pp.210-217
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• 2020

여러 세대가 공존하는 다세대 기술 시장의 경우 성능, 가격 및 진입시점 등의 조정을 통해 다양한 진입모드가 가능하므로, 다세대 기술의 시장진입모드에 대한 이해가 중요하다. 본 연구에서는 다세대 기술의 시장진입모드에 대해 기술, 시간, 성능(또는 가격)의 다차원 관점에서 개념에 대해 정의하고, 다양한 진입모드의 종류에 대해 모형을 제시하고자 하였다. 문헌리뷰를 통해 다세대 기술의 시장진입모드의 정의 및 종류에 대한 모형을 제시하였고, 도출한 모형의 정합성을 반도체 및 스마트폰 시장 사례를 바탕으로 검증하였다. 다세대 기술의 시장진입모드는 6가지 종류(중간 성능 및 일찍 진입 모드, 높은 성능 및 일찍 진입 모드, 낮은 성능 및 일찍 진입 모드, 중간 성능 및 늦게 진입 모드, 높은 성능 및 늦게 진입 모드, 낮은 성능 및 늦게 진입 모드)로 모형화가 가능하였다. 본 연구를 토해 도출한 시장진입모드의 정의 및 종류에 대한 모형은 다세대 기술의 시장진입모드를 이해하는데 유용할 것이고, 다세대 기술 외에도 다른 특성의 시장에서도 적용 가능할 것이다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권10호
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• pp.2395-2410
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• 2013

Many telecommunication operators around the world have multiple networks. The networks run by each operator are always of different generations, such as 2G and 3G or even 4G systems. Each system has unique characters and specified requirements for optimal operation. It brings about resource allocation problem among these networks for the operator, because the budget of each operator is limited. However, the evaluation of resource allocation among various networks under each operator is missing for long, not to mention resource allocation optimization. The operators are dying for an algorithm to end their blind resource allocation, and the Resource Allocation Optimization Algorithm for Multi-network Operator (RAOAMO) proposed in this paper is what the operators want. RAOAMO evaluates and optimizes resource allocation in the view of overall cost for each operator. It outputs a resource distribution target and corresponding optimization suggestion. Evaluation results show that RAOAMO helps operator save overall cost in various cases.

• 천문학회보
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• 제43권1호
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• pp.46.1-46.1
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• 2018

In order to investigate the origin of multiple stellar populations in the halo and bulge of the Milky Way, we have constructed chemical evolution models for the low-mass proto-Galactic subsystems such as globular clusters. Unlike previous studies, we assume that supernova blast waves undergo blowout without expelling the pre-enriched gas, while relatively slow winds of massive stars, together with the winds and ejecta from low and intermediate mass asymptotic-giant-branch stars, are all locally retained in these less massive systems. We find that the observed Na-O anti-correlations in metal-poor GCs can be reproduced when multiple episodes of starbursts are allowed to continue in these subsystems. A specific form of star formation history with decreasing time intervals between the stellar generations, however, is required to obtain this result, which is in good agreement with the parameters obtained from our stellar evolution models for the horizontal-branch. The "mass budget problem" is also much alleviated by our models without ad-hoc assumptions on star formation efficiency and initial mass function. We also applied these models to investigate the origin of super helium-rich red clump stars in the metal-rich bulge as recently suggested by Lee et al. (2015). We find that chemical enrichments by the winds of massive stars can naturally reproduce the required helium enhancement (dY/dZ = 6) for the second-generation stars. Disruption of proto-globular clusters in a hierarchical merging paradigm would have provided helium enhanced stars to the bulge field.

• 한국가금학회지
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• 제17권4호
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• pp.255-268
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• 1990

본 연구는 상업용 난용종계에서 선발에 의한 유전력과 유전상관계수등의 유전모수가 어떤 양상으로 변화하는지를 알아보기 위하여 수행되었다. 분석에 이용된 자료는 백색레그혼종 1계통(Line-W)과 갈색난용종 1계통(Line-B)에 대한 1980년부터 1985년까지의 6년간 5세대 동안의 선발결과에 대한 것으로 표현형 능력 변화와 근친교배의 영향력 분석 및 유전력과 유전상관계수의 추정에 의해 얻어진 결과를 요약하면 다음과 같다. 1. 두 계통의 표현형 능력 변화는 주 선발형질인 300일령 산란수와 400일령 산란수에서, Line-W의 경우는 4세대와 5세대에서 감소한 것으로 나타난 반면, Line-B에서는 희귀분석에 의해 각각 2.87개와 4.25개씩 증가한 것으로 나타났다. 초산일령은 두 계통에서 각각 세대당 1.61일과 4.44일씩 단축된 것으로 분석되었는데, Line-B에서 얻어진 수치는 고도의 유의성을 보였다. Line-W에서 나타난 산란수의 감소추세가 유전적개량의 한계에 의한 것인지의 여부는 대조구 집단에 의한 자료가 없는 한 확인하기가 어려웠다. 2. 폐쇄집단에서 이루어진 선발과정에서 필연적으로 나타날 근친교배의 영향력에 대해 알아보기 위하여 매세대 유효양친수에 의한 근교계수 상승도를 추정한 결과 각각 0.2％와 0.3％로 나타났고, 가계형성원을 조사하여 계산된 세대별 근교계수는 각각 0.8％이하로 나타나서 근친교배로 인한 능력의 저하현상이나 유전모수 추정의 오차는 무시해도 좋을 것으로 판단되었다. 3. 두 계통의 주요 형질에 대한 유전력은 대부분의 형질에서 모 분산에 의한 추정치가 부 분산이나 희귀분석에 의한 추정치에 비해서 높게 나타나, 이들 형질에 미치는 모체효과를 포함한 비상가적 유전변이의 존재를 암시해 주었다. 300일령 산란수와 산란율 등의 형질에 대한 유전력은 두 계통에서 세대 경과에 따라 감소되는 추세를 보였으나, 30주령 및 40주령시에 난중에 대한 유전력 추정치는 세대 경과에 따라 뚜렷한 감소 추세를 보이지 못했다. 또한, 주요 형질 사이의 유전상관계수도 세대 경과에 따라 일정한 방향으로 변화되지 않는 것으로 나타났는데, 이는 여러 형질이 동시에 선발되었고 또 각 형질에 대한 선발비중이 세대별로 일정하지 못했던데서 오는 형질간 유전자 작용의 복합성에 기인되는 것으로 생각되었다.

• 한국환경교육학회지:환경교육
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• 제22권2호
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• pp.1-22
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• 2009

Even though climate change is visibly proceeding and public concern about climate change is increasing both nationally and internationally, teenagers' and students' perception of climate change is relatively low in Korea. Since climate change is a problem with long-term effects, it is young people including children and juveniles of the current generation and future generations who are more affected by climate change. They are the most interested party who should know why climate change happens, what kind of impacts will be given, and how to respond to the problem. Based on the aforementioned concern, this study aims to explore the extent and contents of school education with regard to climate change in Korea as well as in other advanced countries and to provide policy suggestions. This study finds that school climate change education requires consideration of multiple aspects including reorganization of school curriculum, revitalization of related programs by school, expansion of teachers' training chances, in which multiple institutions such as the Ministry of Environment, the Ministry of Education, Science and Technology, Offices of Education are related and, consequently, the activation of climate change education program is by no means simple. Therefore, for effective climate change education in schools, cooperation and coordination of related institutions are essential, along with development of diverse school education curriculums and programs and training programs for teachers.