• 한국콘텐츠학회논문지
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• 제15권10호
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• pp.116-126
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• 2015

본 연구는 중국 전역을 대상으로 종합편성 방송을 하는 CCTV1, 후난위성방송, 강소위성방송이 경쟁이 심화됨에 따라 경쟁에서 이기기 위해 어떠한 방식으로 '프로그램'을 활용하는가를 적소이론의 관점에서 분석하였다. 분석결과 시청률 경쟁이 강화되면서 세 방송사들이 추구한 프로그램 자원의존 전략에 차이가 있는 것으로 나타났다. CCTV1의 경우 프로그램 장르, 제작 방식에 있어 적소폭의 변화가 크지 않아 편성전략에 변화를 주지 않은 것으로 나타난 반면, 후난 위성방송과 강소위성 방송은 적소폭에 변화를 보여 편성전략에 변화를 준 것으로 나타났다. 강소위성 채널은 2012년부터 2014년까지 채널 간 경쟁이 강화되자 꾸준히 적소폭을 늘리는 전략을 추구하였으나, 후난 위성방송의 경우 2013년에는 적소폭을 늘렸으나 2014년에는 프로그램 장르, 제작방식에서 모두 적소폭을 좁히는 전략을 취하였다. 세 방송사들의 차별화된 프로그램 자원의존전략을 방송사들의 시청률과 광고판매액의 증가와 연관시켜 평가하면 강소위성채널이 가장 좋은 성과를 보였다고 평가할 수 있다.

• Journal of Ecology and Environment
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• 제44권3호
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• pp.162-177
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• 2020

Background: Ecologists have achieved much progress in the study of mechanisms that maintain species coexistence and diversity. In this paper, we reviewed a wide range of past research related to these topics, focusing on five theoretical bodies: (1) coexistence by niche differentiation, (2) coexistence without niche differentiation, (3) coexistence along environmental stress gradients, (4) coexistence under non-equilibrium versus equilibrium conditions, and (5) modern perspectives. Results: From the review, we identified that there are few models that can be generally and confidently applicable to different ecological systems. This problem arises mainly because most theories have not been substantiated by enough empirical research based on field data to test various coexistence hypotheses at different spatial scales. We also found that little is still known about the mechanisms of species coexistence under harsh environmental conditions. This is because most previous models treat disturbance as a key factor shaping community structure, but they do not explicitly deal with stressful systems with non-lethal conditions. We evaluated the mainstream ideas of niche differentiation and stochasticity for the coexistence of plant species across salt marsh creeks in southwestern Denmark. The results showed that diversity indices, such as Shannon-Wiener diversity, richness, and evenness, decreased with increasing surface elevation and increased with increasing niche overlap and niche breadth. The two niche parameters linearly decreased with increasing elevation. These findings imply a substantial influence of an equalizing mechanism that reduces differences in relative fitness among species in the highly stressful environments of the marsh. We propose that species evenness increases under very harsh conditions if the associated stress is not lethal. Finally, we present a conceptual model of patterns related to the level of environmental stress and niche characteristics along a microhabitat gradient (i.e., surface elevation). Conclusions: The ecology of stressful systems with non-lethal conditions will be increasingly important as ongoing global-scale climate change extends the period of chronic stresses that are not necessarily fatal to inhabiting plants. We recommend that more ecologists continue this line of research.

• Clinical and Experimental Reproductive Medicine
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• 제40권2호
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• pp.47-54
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• 2013

To overcome the difficulty of controlling stem cell fate and function in applications to regenerative medicine, a number of alternative approaches have been made. Recent reports demonstrate that a non-cellular niche modulating the biophysical microenvironment with chemical factors can support stem cell self-renewal. In our previous studies, early establishment was executed to optimize biophysical factors and it was subsequently found that the microgeometry of the extracellular matrix made huge differences in stem cell behavior and phenotype. We review here a three-dimensional, non-cellular niche designed to support stem cell self-renewal. The characteristics of stem cells under the designed system are further discussed.

• 한국언론정보학보
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• 제19권
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• pp.7-36
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• 2002

본 논문의 목적은 인터넷방송 콘텐츠의 산업적 가능성을 모색해 보기 위해서 기존의 텔레비전 프로그램과 비교하여 어떠한 특성이 나타나는지를 살펴보고자 한다. 본 논문에서는 두 매체의 프로그램간 유사성과 차이점을 분명하게 나타내 보기 위하여 층족적소이론(Niche theory)을 적용하여 보고자 한다. 연구결과, 첫째, 대부분의 장르에서 인터넷방송이 텔레비전보다 적소폭이 좁다는 결과가 도출되었다. 둘째, 교육 장르의 중복값 평균이 가장 높았고, 그 다음은 교양, 오락 순이어서 비교적 다른 장르에 비해서 경쟁적인 관계가 아닌 것으로 나타났다. 반면, 이상의 새 장르를 제외한 6개는 비슷한 정도의 경쟁관자로 형성하고 있는 것으로 나타났다. 셋째, 경쟁적 우위성 분석 결과에서는 인터넷방송이 우위성을 확보하고 있는 기능은 유일하게 음악의 개인적 정보습득 기능이었다. 전체적으로 아직까지는 텔레비전이 인터넷방송에 비해서 경쟁적인 매체가 아니라는 것을 알 수 있었다. 그러므로 인터넷방송은 텔레비전과는 다른 새로운 포맷 개발이 필요하다고 할 수 있겠다.

• 한국수산과학회지
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• 제28권6호
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• pp.805-811
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• 1995

Final biomass yields (peak optical density) and growth rates (divisions/day) of seven clones of Skeletonema costatum from Korean coastal waters were measured to understand their intraspecific variations in the light intensity niche component under $25^{\circ}C$ condition. Daily growth rates of 6 of 7 S. costatum, clones were maximum at 6000 lux while that of YS4, a neritic clone, was maximum at 9000 lux. The final biomass yields of 4 of the 7 S. costatum clones were maximum at the lowest light intensity of 2000 lux. Minimum final biomass yields were found at 9000 lux in all the S. costatum clones other than an estuarine clone, HDC9. The intraspecific variations of the mean growth rate and mean final biomass yield under each of the three different light intensity in terms of the coefficient of variation were not greater than 10% in any of the 7 S. costatum clones.

• 한국산학기술학회논문지
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• 제14권5호
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• pp.2121-2130
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• 2013

본 연구는, 팬덤 커뮤니티의 창작과 생산을 통해 부상하는 무수한 UCC 클라우드(cloud)가 리드 유저에 의한 틈새 창출 과정임을 드라마 다모의 커뮤니티를 사례를 통해 실증적으로 분석하였다. 연구 결과, 첫째, 드라마 애호가와 팬픽션 작가들은 드라마 소비자들이자 UCC 창작/생산자로서 팬덤 커뮤니티에서 자신들의 니즈에 맞는 사용자 맞춤형 콘텐츠인 UCC와 팬픽션을 만드는 과정을 통해 원작 드라마와는 전혀 다른 틈새를 창출한다. 둘째, 커뮤니티의 크리에이티브 유저들이 만드는 드라마에 대한 소비/평가, 시청자 요구/적응, 유저의 창작/생산이라는 순차적인 흐름은 드라마 정보를 제공하고 의도적으로 자원을 공급/확산시키며 파생 상품을 생산하는 미디어 기업의 흐름과 상호작용하는 공진화(coevolution) 관계를 보여준다. 셋째, UCC와 팬픽션을 둘러싼 드라마 팬덤 커뮤니티의 활동은 드라마에 대한 재미와 놀이 그리고 공감을 넘어 지식이 투입되는 창작과 생산의 결과물을 통해 비상업적 활동이 시장과 지속적으로 연계되어 선순환되는 새로운 패러다임의 드라마 생태계를 형성하고 있다.

• 한국환경복원기술학회지
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• 제16권1호
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• pp.159-170
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• 2013

The effect of climate change on urban woody plants remains difficult to predict in urban areas. Depending on its tolerances, a plant species may stay and survive or stay with slowly declining remnant populations under a changing climate. To predict those vulnerabilities on urban woody plants, this study suggests a basic bioclimatic envelop model of heat requirements, cold tolerance, chilling requirements and moisture requirements that are well documented as the 'climatic niche'. Each component of the 'climatic niche' is measured by the warmth index, the absolute minimum temperature, the number of chilling weeks and the water balance. Regarding the utility of the developed model, the selected urban plant's present probabilities are suggested in the future climate of Seoul. Both Korea and Japan's thermal thresholds are considered for a plant's optimal climatic niche. By considering the thermal thresholds of these two regions for the same species, the different responses observed will reflect the plant's 'hardening' process in a rising climate. The model illustrated that the subpolar plants Taxus cuspidata and Ulmus davidiana var. japonica are predicted to have low suitability in Seoul. The temperate plants Zelkova serrata and Pinus densiflora, which have a broad climatic niche, exhibited the highest present probability in the future. The subtropical plants Camellia japonica and Castanopsis cuspidata var. sieboldii may exhibit a modest growth pattern in the late 21C's future climatic period when an appropriate frost management scheme is offered. The model can be used to hypothesize how urban ecosystems could change over time. Moreover, the developed model can be used to establish selection guidelines for urban plants with high levels of climatic adaptability.

• 한국수정란이식학회지
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• 제29권3호
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• pp.221-228
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• 2014

Despite that porcine spermatogonial stem cells (pSSCs) have been regarded as a practical tool for preserving eternally genetic backgrounds derived from pigs with high performance in the economic traits or phenotypes of specific human diseases, there were no reports about precise definition of niche conditions promoting proliferation and maintenance of pSSCs. Accordingly, we tried to determine niche conditions supporting proliferation and maintenance of undifferentiated pSSCs for short-term. For these, undifferentiated pSSCs were progressively cultured in different composition of culture medium, seeding density of pSSCs, type of feeder cells and concentration of growth factors, and then total number of and alkaline phosphatase (AP) activity of pSSCs were investigated at post-6 day culture. As the results, the culture of $4{\times}10^5$ pSSCs on mitotically in activated $2{\times}10^5$ STO cells in the mouse embryonic stem cell culture medium (mESCCM) supplemented with 30 ng/ml glial cell line-derived neurotrophic factor (GDNF) was identified as the best niche condition supporting effectively the short-term maintenance of undifferentiated pSSCs. Moreover, the optimized short-term culture system will be a basis for developing long-term culture system of pSSCs in the following researches.

• Journal of Magnetics
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• 제21권4호
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• pp.660-665
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• 2016

The electromagnetic apparatus plays an important role in high power electrical systems. It is of great importance to provide an effective approach for the optimization of the high power electromagnetic apparatus. However, premature convergence and few Pareto solution set of the optimization for electromagnetic apparatus always happen. This paper proposed a modified multi-objective particle swarm optimization algorithm based on the niche sorting strategy. Applying to the modified algorithm, this paper guarantee the better Pareto optimal front with an enhanced distribution. Aiming at shortcomings in the closing bounce and slow breaking velocity of electromagnetic apparatus, the multi-objective optimization model was established on the basis of the traditional optimization. Besides, by means of the improved multi-objective particle swarm optimization algorithm, this paper processed the model and obtained a series of optimized parameters (decision variables). Compared with other different classical algorithms, the modified algorithm has a satisfactory performance in the multi-objective optimization problems in the electromagnetic apparatus.

• The Korean Journal of Ecology
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• 제7권4호
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• pp.208-232
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• 1984

A survey was conducted on the vegetation of Seogmo island, which is small island (ca. 41 okm2) located about 1km west of Kanghwa island in the central Korea, from Aug. 1983 to May 1984. Based on the field data, actual vegetation map and potential natural vegetation map were made. The island is covered with broad-leaved trees dominated with Quercus variabilis. The dominance diversity curves obtaiend in different associations are grouped in two types, lognormal distribution forms at the undisturbed vegetation and geometric series at the disturbed or rocky sites. It seems that the curves show to us the nature of their ecocline by the hypothesis of some investigators, i.e. Random niche boundary hypothesis, niche preemption hypothesis, lognormal distribution and logarithmic series. Total numbers of vascular plant species of the island were recorded 108 families, 348 genera, 475 species, 73 variaties and 7 forma. And Pte.-Q Index, 0.93, and Fisher's Index, 589.8, were higher than those in neighboring islands.