• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.191-192
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• 2003

수산양식에 있어서 초기 치자어의 영양은 치자어의 생존 및 성장에 많은 영향을 미친다. 이와 같은 영양에는 주로 DHA와 EPA 등으로 많은 연구자들은 그 초점을 두고 있다. 그러나, 실제 어류에 있어서 부화 직후의 영양소 섭식 능력은 많은 종에 있어서 미지수로 종묘생산시 초기 감모기를 겪고 있으며 이 시기를 부화 후 first feeding 단계의 5∼10일로 잡고 있다. 그러나 이 초기 감모기를 지난 자치어는 rotifer와 Artemia 같은 살아있는 먹이생물을 이용하기에 충분하기 때문에 생존율에는 큰 영향이 없는 것으로 보고되어지고 있다. (중략)

• 한국벤처창업학회:학술대회논문집
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• 2020.06a
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• pp.113-121
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• 2020

최근 정부가 창업기업에게 3년간 공공금융기관 등을 통해 약 100조원 투입하였으며, 금융위원회가 신용보증기관과 산업은행 등 정책금융 등의 많은 창업지원 자금을 통해 약 35조원을 지원하는 등 최근 3년간(2015년~2018년) 창업기업에 약 100조원 이상을 지원하였다. 실제로 중소기업청의 지원예산 중 스타트업 지원 비중은 85%에 달한 반면 스케일업(성장·성숙기)지원은 15%에 불과하다. 그러나 국내 창업기업의 생존율은 선진국에 비해 턱없이 낮은 것으로 조사되었다. 창업 후 3년간 생존율은 39.1%로 10곳 중 4곳 정도만 살아남는 것으로 조사되었고, 5년간 살아남을 확률은 27.5% 10곳 중 3곳 정도만 살아남는다. 반면 해외 창업기업들은 5년간 창업기업 생존율은 우리나라의 2배에 달한다. 이에 따라 본 연구는 최근 정부의 적극적인 지원이 이루어지고 있는 초기창업자에 대한 연구의 필요성과 함께 창업동기와 창업준비가 사업계속의도에 미치는 영향관계에서 창업만족도의 매개역할에 관한 영향을 실증적으로 분석하고 살펴보고자 한다. 또한, 초기창업자의 창업동기와 창업준비에 기초하여 창업을 한 후에 창업에 대한 만족도를 높일 수 있는 방법보다는 창업 전 부터 사전 준비의 필요성을 고찰하고자 한다. 이러한 관점에서 실무적 시사점을 도출하고, 초기창업자들의 창업만족도를 높이고 계속 가능한 창업수행을 할 수 있도록 유용한 정책적 시사점을 제시하고자 한다.

• Journal of Korean Society of Forest Science
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• v.109 no.4
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• pp.413-420
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• 2020

We analyzed the growth characteristics of each cell line and acclimating substrate of Larix kaempferi plantlets regenerated from somatic embryos, with the goal of increasing the survival rate during the acclimation phase. Somatic embryos from three embryogenic cell lines (L14-66, L16-18, and L17-B4) were used, and the acclimating substrates were commercial soils for Larix species (Larix-Soil) and horticultural corps (Hort-Soil), Elle-pot, and Peat-plug. The average initial shoot and root length was shortest in L14-66 and longest in L17-B4. The average survival rate by cell line was highest (87.0%) in L17-B4 and lowest (64.3%) for L14-66. Survival rates by substrate were highest in Elle-pot (88.5%) and Peat-plug (88.9%). The initial shoot length of the L14-66 plantlets was highly correlated with survival rates in the Larix-Soil (r = 0.852), Hort-Soil (r = 0.692), and Elle-pot (r = 0.867) substrates, but not in Peat-plug with high total nitrogen content. The initial shoot length of the L17-B4 plantlets was not correlated with the survival rate in any of the substrates. The initial root length of the L14-66 plantlets was highly related to survival rates in the Larix-Soil (r = 0.986), Elle-pot (r = 0.846), and Peat-plug (r = 0.802) substrates, and the survival rate of the plantlets was higher as the initial root length was longer. The initial root length of the L17-B4 plantlets was related to survival rate only in the Larix-Soil (r = 0.896) and Elle-pot (r = 0.696) substrates. In conclusion, to increase the survival rate of plantlets, root length should be considered over shoot length, and it is recommended to use substrates with high nitrogen content, such as Peat-plug, or to add fertilizer, during the acclimating process. In addition, in order to increase the survival rate, lines with high initial growth should be developed.

• 한국벤처창업학회:학술대회논문집
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• 2018.11a
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• pp.283-288
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• 2018

스타트업의 자금조달 능력은 초기 스타트업 생존에 가장 직결되는 문제이다. 스타트업은 정부 지원금을 비롯하여 엔젤투자자, 벤처캐피탈 등으로부터 자금을 지원받고 있지만 초기기업 회수시장의 불확실성으로 인해 투자 규모는 작은 편이다. 이에 따라 초기기업에 투자함과 동시에 경영 및 기술 멘토링, 교육, 관리 등을 체계적으로 지원하는 '액셀러레이터'가 최근 창업생태계의 핵심으로 떠오르고 있다. 액셀러레이터는 단순하게 인큐베이팅 시스템을 제공하는 것이 아니다. 초기기업의 팀빌딩부터 성장 과정을 함께하는 '공동 창업자'와 같은 역할을 하면서 이들이 성장해나갈 수 있도록 집중적인 멘토링과 교육 등의 프로그램을 제공한다. 이러한 시스템을 거친 스타트업은 생존 기간이 상대적으로 높고, 벤처캐피탈도 이렇게 성장한 스타트업 투자에 보다 더 적극적으로 참여하는 경향이 있다. 하지만 액셀러레이터 설립의 역사가 오래되지 않아, 관련 연구는 비교적 다양하지 않은 편이다. 이에 본 연구에서는 엔젤투자자, 벤처캐피탈과 다른 액셀러레이터의 특징이 무엇인지 분석하고, 특히 액셀러레이터가 스타트업 투자의사결정시 영향을 미치는 요인에는 어떤 것들이 있는지 렌즈모델을 통해 알아보고자 한다.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.274-279
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• 2011

In order to know the effect of seed size on the early plant life history, we measured the rate of germination, early growth and winter survival of four oak species with different acorn size (large, medium and small). The mean germination rate was higher in the larger seed species ($Q.$ $acutissima$ and ($Q.$ $variabilis$) than those of the smaller seed species ($Q.$ $aliena$ and $Q.$ $serrata$). Within $Q.$ $variabilis$, the germination rate decreased with larger acorn size class but that of rest other species was not significantly affected by the acorn size. The early mean growth rate decreased with acorn size in the order of $Q.$ $acutissima$, $Q.$ $variabilis$, $Q.$ $aliena$ and $Q.$ $serrata$. The early mean growth rate was higher in large or medium size than in small size of $Q.$ $acutissima$ and $Q.$ $variabilis$, but it showed no difference with acorn size in $Q.$ $aliena$ and $Q.$ $serrata$. Survival rate in winter was the highest in the medium acorn size among 4 oak species, the seedling of $Q.$ $serrata$ and $Q.$ $variabilis$ did not survive in both large and small acorn size. These results indicate that seed size influences a different effect on the early plant life history stage.

• Korean Journal of Ichthyology
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• v.22 no.1
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• pp.25-33
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• 2010

Effects of different salinity levels on spawning performance, embryonic development and early viability of a euryhaline medaka species, Oryzias dancena, were examined. O. dancena were able to spawn eggs in a wide range of salinity from 0 to 70$^{\circ}/_{\circ\circ}$, however, the spawning frequency was lowered in complete freshwater (0$^{\circ}/_{\circ\circ}$) and in highly salted water (70$^{\circ}/_{\circ\circ}$). Fertilization success was negatively affected when the environmental salinity was higher than the salt concentration found in normal seawater. Embryonic viability and hatching success were also inversely related with the salinity levels. Typical abnormality was observed in developing embryos incubated at high salinities (30, 45 and 60$^{\circ}/_{\circ\circ}$). In addition, the time to hatch was significantly delayed with increasing salinities: peak hatching occurred at 12~14 days post fertilization (dpf) in freshwater and at least at 17 to 18 dpf in 60$^{\circ}/_{\circ\circ}$. Mean survival rates of the hatched larvae up to 7 days post hatching (dph) were at least 97% in salinity levels ranging from 0 to 30$^{\circ}/_{\circ\circ}$. However, larvae reared in 45 and 60$^{\circ}/_{\circ\circ}$ experienced significant mortality, especially in the early phase, resulting in only 75% and 64% survival rates up to 7 dph, respectively.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.1
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• pp.28-40
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• 2010

Purpose: The aim of this retrospective study was to provide long-term data about the correlation between multifactorial local factors and the survival of implants. Material and methods: During 19 years (1991 to 2009), 2796 implants were placed in 879 patients. From dental charts and radiographs, the following data were collected: patient's age at implant placement, gender, implant system, surface, length, diameter, location of implant placement, bone quality, primary stability, type of prosthesis. The correlations between these data and implant survival were analyzed. Statistical analysis was performed using Kaplan-Meier survival analysis, Chi-square test, odds ratio. Results: 1. Among the 2796 implants, 150 implants failed that resulted in a cumulative survival rate of 94.64%. The cumulative survival rate of smooth surface implants (91.76%) was lower than rough surface implants (96.02%). 2. Anatomic location, implant surface, diameter of smooth surface implant, primary stability, type of prosthesis, patient's age and gender were significantly associated with implant survival (P < .05). 3. No significant difference in implant survival was found in relation to the following factors: implant length, bone quality, diameter of rough surface implants and type of rough surface according to implant manufacturer (P < .05). Conclusions: Local factors such as anatomic location, implant surface, diameter of smooth surface implant, primary stability and type of prosthesis have a significant effect on implant survival.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1999.05a
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• pp.205-209
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• 1999

일반화된 지수생존모형(generalized exponential survival model)을 고려하여 이 모형의 모수를 추정하는 수정된 FS(modified Fisher scoring)방법을 제안한다. 이를 위해 우도방정식(likelihood equation)을 유도하고 초기추정치 (initial estimate)를 포함한 추정알고리즘(estimating algorithm)을 개발한다.

• Development and Reproduction
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• v.5 no.1
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• pp.35-38
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• 2001

This study was peformed to find out the optimum larval stage among trochophore, early Dshaped larva, late D-shaped larva, early umbo and late umbo stages for cryopreservation of surf clam, Spisula sachalinensis larvae. Dimethyl sulfoxide (DMSO)and ethylene glycol were used as cryoprotectant, The larvae were immersed to cryoprotectants for 10 minutes and thereafter, cryopreserved in liquid nitrogen. Survival rates of trochophores frozen-thawed in 2.0 M dimethyl sulfoxide and 2.0 M ethylene glycol were the highest as 97.4% and 85.0%, respectively and post-thaw survival rates were decreased with the larval growth.

• Korean Journal of Ecology and Environment
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• v.46 no.3
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• pp.395-408
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• 2013

Environmental condition can induce changes in early life-history traits in order to maximise the ecological fitness. Here I investigated how temperature change and variation in human aquatic activity/behaviour affect early life-history consequences in fish using a dynamic-state-dependent model. In this study, I developed a general fish's life-history model including three life-history states depend-ing on foraging activity, such as body mass, mass of reproductive tissue (i.e., gonadal development) and accumulated stress (i.e., cellular or physiological damage). I assumed the level of foraging activity maximises reproductive success-ultimately, fitness. The model predicts that growth rate, development of reproductive tissues and damage accumulation are greater in higher temperature whereas higher human aquatic activity rapidly reduced the growth rate and development of reproductive tissue and increased damage accumulation. While higher foraging activity in higher temperature is less affected by human aquatic activity, the foraging activity in lower temperature rapidly declined with human aquatic activity. Moreover, lower survival rate in higher temperature or human aquatic activity was independent on mortality rate due to human aquatic activity or mortality rate when foraging activity, respectively. However, the survival rate in lower temperature or human aquatic activity was dependent on these mortality rates. My findings suggest that including of early life-history traits in relation to climate-change and human aquatic activity on the analysis may improve conservation plan and health assessment in aquatic ecosystem.