• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2007.02a
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• pp.108-111
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• 2007

무선 센서 네트워크 환경에서 센서 필드에 배치된 센서 노드들 사이에 안전한 통신 인프라를 구성하기 위해 보안 키 설립이 필요하다. 현재까지 센서 노드들 사이의 보안 키 설립에 대한 여러 가지 기법들이 제안되어 왔으며 최근에는 배치 전 센서 노드들의 예측위치를 이용한 개선된 기법들이 제안되고있다. 현재까지 제안된 위치기반 기법들은 선택적인 노드포획에 안전하게 설계하기 위해 상대적으로 높은 키 저장량과 키 생성을 위한 많은 연산량을 요구한다. 우리는 위치 기반 기법에서는 단순히 piar-wise키를 저장하는 것이 저장량이나 연산량 면에서 효율적이라는 분석을 제시하고 pair-wise키를 이용하여 공격자의 선택적인 노드 포획에도 강한 효율적인 위치 기반 기법을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10a
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• pp.285-288
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• 2000

본 논문에서는 다중 에이전트(multi-agent) 환경에서 에이전트들의 행동을 효율적으로 조정 (coordination)하기 위해 강화 학습(reinforcement learning)을 이용하였다. 제안된 방법은 각 에이전트가 목표(goal)와의 거리 관계(distance relationship)와 인접 에이전트들과의 공간 관계(spatial relationship)를 이용하였다. 그러므로 각 에이전트는 다른 에이전트와 충돌(collision) 현상이 발생하지 않으면서, 최적의 다음 상태를 선택할 수 있다. 또한, 상태 공간으로부터 입력되는 강화 값이 0과 1 사이의 값을 갖기 때문에 각 에이전트가 선택한 (상태, 행동) 쌍이 얼마나 좋은가를 나타낼 수 있다. 제안된 방법을 먹이 포획 문제(prey pursuit problem)에 적용한 결과 지역 제어(local control)나. 분산 제어(distributed control) 전략을 이용한 방법보다 여러 에이전트들의 행동을 효율적으로 조정할 수 있었으며, 매우 빠르게 먹이를 포획할 수 있음을 알 수 있었다.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.693-694
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• 2004

• Korean Journal of Ecology and Environment
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• v.42 no.3
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• pp.290-294
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• 2009

Larval development of Nannopaya pygmaea Rambur (Libellulidae), an endangered dragonfly in Korea, was studied using an introduced lariat population in an artificial wetland habitat. Artificial habitat was created in a green house which imitated a small wetland in Boryeong-si, Chungcheongnam-do, Korea, where N. pygmaea inhabited. A total of 300 N. pygmaea larvae were introduced to the artificial habitat in June 2007. Larvae were recaptured five times between June 2007 and November 2008 for measurement of body length. As a result, the initial and recaptured populations (Recaptured I, II, III, IV, and V populations, respectively) contained two body size groups [initial 6.20$\pm$0.34 mm and 7.94$\pm$0.46 mm (mean$\pm$SD); Recaptured I 2.84$\pm$0.43 mm and 5.16$\pm$0.83 mm; Recaptured II 5.96$\pm$0.66 mm and 8.02$\pm$0.35 mm; Recaptured III 5.97$\pm$0.73 mm and 7.82$\pm$0.37 mm; Recaptured IV 7.04$\pm$0.93 mm and 8.52$\pm$0.39 mm; Recaptured V 5.72$\pm$0.60 mm and 7.71$\pm$0.30 mm]. Our rearing experiment evidenced that the recaptured I-V populations are the offspring of the initial population and the offspring grew approximately 3 mm at 470 degree days. It was also estimated that N. pygmaea larvae need approximately 100 degree days to grow 0.7 mm in body length.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1984-1988
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• 2009

본 연구에서는 하천 식생 및 어류 모니터링 결과를 바탕으로 청미천 유역의 본류에 대한 하천 수변환경을 평가하였다. 하천 식생은 홍수 전과 후로 구분하여 2회 조사하였다. 식생 조사는 Braun-Blanque의 조사 방법에 따라 표본구 내의 출현식물에 대해 조사하였고 표본구 면적은 자생지 주변의 특징과 형성된 군락의 최소면적에 근거하여 $2{\ast}2m^2$ 결정하였다. 1, 2차 조사 결과 공히 국화과 식물이 많이 출현하였고 다음으로 벼과 식물이 많이 출현하였다. 청미천 조사구간에서 볼 수 있는 식물은 21개과 38종이 출현하고 있는 것으로 조사되었다. 이중 국화과 7종과 벼과 5종, 콩과 4종으로 출현종이 많이 조사되었다. 화봉천 합류점에서는 총 123마리를 포획하여 동종 분류한 결과 1개과 3개아과 7개종이 출현하였다. 1지점의 경우 출현어종은 모두 잉어과로 피라미가 48%로 우점종을 차지하고 있었다. 죽산천 합류지점에서는 총 83마리를 포획하였으며, 출현어종은 1개과 2개아과 7개종의 어류이며 그중 붕어와 피라미가 각각 31%와 23%로 우점하고 있었다. 청미천 조사구간의 출현어종의 개체수를 보면 피라미 68.5%, 붕어 44.3%, 떡붕어 18.1%, 모래무지 14.3%, 왜매치 14.1% 순으로 나타나고 있으며 기타 출현어종은 대부분 4% 내외로 피라미가 우점종으로 조사되었다.

• Journal of Astronomy and Space Sciences
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• v.18 no.2
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• pp.153-162
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• 2001

In this paper, space radiation environment and total ionizing dose(TID) effect have been analyzed for the KOMPSAT-2 operational orbit. It has been revealed that the trapped protons are concentrated in the SAA(South Atlantic Anomaly) area and that the trapped protons and electrons, and solar protons are main factors affecting TID. It turned out that low energy Particles can be effectively blocked by aluminum shielding thickness, but high energy Particles can not be effectively blocked by increasing aluminum shielding thickness. KOMPSAT-2 total radiation dose which is accumulated continuously to spacecraft electronics has been expressed as the function of aluminum thickness. These values ran be used as the criteria for the selection of electronic parts and shielding thinkness of the KOMPSAT-2 structure or electronic box.

• The Journal of the Petrological Society of Korea
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• v.5 no.1
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• pp.1-9
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• 1996

Eonyang amethyst deposits are thought to be spatially and temporally associated with the biotite granite of the Kyeongsang Basin. The examined euhedral quartz crystals in cavities in the aplite intruded biotite granite are colored-zoned from white at the base to amethystine at the tops. Three types of primary Inclusions were observed and three is representing each types are constructed to constrain the trapping conditions and fluid evolution involved during the formation of the amethyst. The intersection of the isochore representing the early fluid inclusions with solidus temperature of the host granite indicates initial quartz formation at about $600^{\circ}C$ and 1.0-1.5 kbars . Intermediate quartz formation, associated with the high-salinity inclusions, occurred at somewhat lower temperatures ($400^{circ}c$) and pressures of about 1 kbar. The amethystine quartz formed from $H_2O$-$CO_2$-NaCl fluids at temperatures between 280-$400^{circ}c$ and pressures of about 1 kbar. Early quartz is interpreted to have formed from fluids that either exsolved from or were in equilibrium with the granite at near solidus conditions, whereas the amethystine quartz apparently grew from fluids of at least partial sedimentary origin.

• Journal of Environmental Impact Assessment
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• v.25 no.6
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• pp.477-486
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• 2016

We investigated the growth pattern of Red-tongued viper snakes (Gloydius ussuriensis), which were captured from the islet of the Jeju Island, Gapado between April, 2006 and November, 2009. The results indicated that there were some snakes that grew relatively fast, but most snakes either almost did not grow or grew around 10mm in snout-vent length during one year period. High growth rates was April and June. Since the growth rate of snakes is highly correlated with their foods, these results implied that the feeding activity of Red-tongued viper snakes is high during this period compared to other months. In female, difference in body condition between good-conditioned and bad-conditioned snakes became large as time elapsed from April to June. The body condition of the male Red-tongued viper snakes improved with the progression of time from April till June. Many of the Red-tongued viper snakes were captured between April and June, while they were rarely captured between July and September. Some of the Red-tongued viper snakes were captured during the autumn season. This tendency was because snakes were rarely active during hibernation and peak summer seasons. Thus, Red-tongued viper snakes are active between April and June and between September and November. They then go into hibernation as the temperature dropped in November. Furthermore, the limitation of the movement period of the Red-tongued viper snakes restricted their feeding activities while foods became scarce, which ultimately restricted their overall growth rate. The growth rate of the snakes decreased with age. The snout-vent length of the Red-tongued viper snakes and growth rate showed a negative correlation (r = -0.591), however, it was not statistically significant due to small sample size. The findings from this study could provide meaningful information in the further study of the life cycle of Red-tongued viper snakes.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2006.10a
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• pp.82-85
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• 2006

• Journal of Korean Society of Forest Science
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• v.108 no.1
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• pp.127-132
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• 2019

This study aimed to investigate the differences in habitat environment and characteristics of small rodent populations with time elapse after thinning in Japanese larch (Larix kaempferi) plantations, Mt. Janggun, Gyeongbuk Province, South Korea. We found that there were significant differences in habitat environment, number of tree, shrub stems, coverage of overstory, midstory, rock and number of coarse woody debris (CWD) between thinned and unthinned forest stands. We captured four small rodent species. Total number of captured small rodent were higher in thinned stands. Male-to-female ratio of Apodemus agrarius, and A. peninsulae were both the highest in forest stand 3 year after thinning. The differences in number of captured and sex ratio of small rodents might be related to habitat environment between thinned and unthinned stands. Thus, thinning can provide good habitat for small rodents by developing understory vegetation and increasing CWD in Japanese larch plantations. These results suggest that forest management through maintenance of CWD and induction of midstory and understory vegetation after thinning is necessary to maintain small rodents diversity.