• Journal of KIISE:Computer Systems and Theory
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• v.31 no.7
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• pp.397-401
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• 2004

In an edge-weighted(positive, negative, or zero weights are possible) tree, we want to solve the problem of finding a longest path such that the sum of the weights of the edges in the path is non-negative. We present an algorithm to find a longest non-negative path of a degree 3 tree in Ο(n log n) time, where n is the number of nodes in the tree.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.13-15
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• 2001

최근에 이르러 프로세서의 병렬성을 분석적 기법으로 예측하기 위한 연구가 활발해지면서 프로세서의 성능 예측 모델에 대한중요성이 대두되고 있다. 그러나 기존의 연구는 현재 광범위하게 사용되고 있는 다중 분기 예측법을 이용하는 프로세서에 대하여 분기 차수와 관계없는 재귀적 성능 모델을 제공해주지 않는다. 본 논문에서는 이것을 해결하기 위하여, 매 싸이클마다 명령어 종속 트리를 구성하고 종속인 명령어 간에 상대적인 병렬도 갓을 부여하여 성능 예측 모델 입력 데이타를 측정하였다. 그 곁과, 다중 분기 예측법을 사용하는 프로세서에서 정수형 프로그램에 대한 성능을 기존의 성능모델보다 작은 상대 오차로 예측할 수 있다.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10c
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• pp.479-481
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• 1998

Noise가 있는 data에서 shape나 parameter를 찾았을 때 일반적으로 Hough transform이나 regression을 적용한다. Hough transform은 parameter space의 차수가 커지면 memory 문제가 존재하며, regression 모델은 한 개의 변수를 다른 변수의 함수로 가정하여 error를 최소화하여 데이터중 1 set의 parameter만 존재한다는 가정을 하여야 하는 문제점이 있다. 본 논문에서는 이러한 두 방법의 단점들을 보완하며, Fuzzy개념을 도입한 data fitting 방법을 제안하였다. 이 문제는 genetic algorithm을 도입하여 data를 Fuzzy membership을 갖는 것으로 가정한 최적화 문제로 해결하였다. 직선과 평면에 대한 실험 결과를 보인다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2004.11a
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• pp.50-53
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• 2004

하천 분기특성을 이용한 유출해석모형에서 최소하천의 크기는 매우 민감한 영향을 미치게 되므로 본 연구에서는 금호강 중류의 금호수위표지점 상류 유역을 대상으로 하여 DEM 격자크기와 최소차 하천의 임계면적에 따른 지형매개변수의 변화특성을 검토하였다. 분석에서는 유역내의 1:25,000 수치지형도를 $10\times10,\;30\times30,\;50\times50m$ 격자망으로 구성하여 하천차수별 개수, 유로연장, 면적, 만곡도, 배수밀도 및 유로연장 등을 대상으로 하였다.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.109-114
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• 2011

The objective of this study was to investigate the effects of environments (farms born, testing groups, age at the tests, date at slaughter, ages at slaughter) on body weights at 6, 12, 18 and 24 months of ages, body type measurements at 18 months of age and carcass characteristics in Hanwoo steer populations that were collected from commercial farms and reared in a progeny testing station. Performances of a total of 1,838 steer calves set for tests from 2004 to 2008 were recorded. Carcass characteristics were the carcass grading results evaluated and data collected slaughter scores at 24 months of age. For growth traits of all age classes and body type traits measured at 18 months of age, farms born, test group and linear covariate of age at test were fit in the models. For carcass traits, date at slaughter and linear covariate of ages at slaughter were fit in the models. Effect of farm at birth was not significant for body weight at 24 months of age. Carcass weight, eye muscle area, yield score and back fat thickness were affected by dates at slaughter but not by the ages at slaughter. Marbling score, however, was affected by these two effects. Farms at birth did not seem to affect body type measures greatly. This study will be utilized for Hanwoo Steers genetic evaluation.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.69-81
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• 2010

This study was conducted at 25 sites of 6 mainstreams and 19 tributaries sites within Heuck Stream watershed during May~October 2003 for the survey of fish distributions, compositions, and community characteristics. The survey showed that total fish was identified as 9 family and 26 species in all sites, and Cyprinidae dominated the community as 15 species. The dominant species of >20% of the total were Zacco temminckii (29%), Zacco platypus (22%), and Rhynchocypris oxycephalus (21%) in the watershed. Community analysis, based on the stream spatial gradients, indicated composition differences along the main axis of the stream from the headwater to the downstream; R. oxycephalus predominated in the most headwater zone and Z. temminckii dominated in the lower headwater zone, whereas Z. temminckii -Z. platypus dominated in the mid-to-downstream, and Z. platypus dominated the community in the most downstream zone. Total endemic species was 7 family and 15 species, which is made of 50% in the fish community, so that the high proportion of endemic species indicated a healthy region in terms of fish community, compared to average 23% in Korean peninsula in general. The total number and species of fish increased as the stream order (stream size) increased, indicating that impacts on chemical pollution or habitat disturbance were not so large to the fish community in this watershed. Trophic and tolerance guilds analysis showed that relative proportions of sensitive and insectivore species were >50% in the watershed and decreased as the stream order increased, whereas relative proportions of tolerant and omnivore species showed an opposite results. These outcomes suggest that the natural condition of watershed is preserved relatively and the region should be protected from the chemical and habitat disturbace by agricultural activity and urban developments.

• Journal of Korean Society of Forest Science
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• v.110 no.2
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• pp.233-243
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• 2021

Considering worldwide efforts to mitigate repercussions of climate change, the South Korean government has declared to reach net zero by 2050 to achieve a carbon-neutral sustainable society. For full implementation of NDCs, the government has actively reflected its forestry sector into these strategies. Since coarse woody debris (CWD) in forests represents an enduring carbon storage, it is of particular significance to determine characteristics of changes in carbon stocks of CWD by utilizing data on dead trees monitored in permanent sample plots within national forest inventories (NFIs). In this study, therefore, both occurrence and carbon stocks of CWD were estimated in such plots using data on CWD from the 5^th, 6^th, and 7^th NFIs. Subsequently, characteristics of changes in carbon stocks over time were analyzed. Based on the analysis of 2,021 plots available for monitoring in each NFI of Gangwon Province, the volume of CWD (m³ ha^-1) was found to be 4.71 in the 5^th NFI and 4.09 in the 6^th NFI. However, the volume of CWD declined to 3.09 in the 7^th NFI. Moreover, the annual carbon stocks of CWD (ton C ha^-1) were estimated to be 0.67 in 2009, 0.64 in 2014, and 0.41 in 2019, showing a downward trend over time. This study provides a basis for future research to investigate long-term changes and estimate carbon stocks of CWD in South Korea forests.

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.2
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• pp.78-83
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• 1986

This experiment was carried out in order to study the effect of cutting time on the regrowth and the feed composition in native reed. The first growth crops cut in June, July and October and the ratoon crops after cutting cut in October. The samples measured the plant height, leaf blade & sheath-stem ratio, grass yield, feed composition and invitro dry matter digestibility. The results are summarized as follow: 1. As the result of the grass productivity and nutrient yield, it was indicated that suitable cutting time of the native reed was from middle of June to middle of July. The yield of dry matter and in vitro digestible dry matter were much more in the first crops than in the ratoon crops in both of non-fertilizer and fertilizer(P < 0.01), and more in the fertilizer than in non-fertilizer in both of the first and ratoon crops(P < 0.01). 2. The contents of feed composition in native reed of non-fertilizer and fertilizer showed different trends between the first and ratoon crops. In case of the first crops, the contents of C. protein and C.fat were higher in fertilizer than in non-fertilizer and the contents of C. fiber, NDF and ADF were lower in fertilizer than in non-fertilizer, but these contents were not significantly different between non-fertilizer and fertilizer. In the ratoon crops, these contents between non-fertilizer and fertilizer were shown in a opposite manner to those in the first crops.

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.2
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• pp.84-90
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• 1986

This experiment was carried out to evaluate the effect of cutting frequency and the last cutting date on the dry matter yield, the initial characteristics of spring growth, the yield of the first crops after winter, crude protein and crude fiber yield and the correlation efficients among the above items in timothy-dominated award. Cutting frequency was scheduled by 2, 3 and 4 times a year as main plot and the last cutting date in autumm were sept. 30, Oct. 10 and Oct. 20 as subplot. Experiment was arranged as a split-plot design with three replications and was performed for 4 years from 1980 to 1983 at the alpine area. The results obtained are summarized as follows: 1. The start of spring growth was somehow early as cutting frequency increased but not significant, and was not influenced by the last cutting data. 2. The dry matter yield was decreased by cutting frequency, but was not affected by the last cutting data. 3. The dry matter yield of the first crops after winter significantly decreased by cutting frequency, but failed to show and significant differences by the last cutting date. 4. Crude protein yield was increased by cutting frequency, while dry matter percentage was decreased. Crude fiber yield did not show the same trends. 5. There was a significant positive correlation between DM yield and DM percentage and yield of the first crops after winter, and between DM percentage and yield of the first crops after winter. However, there was a significant negative correlation between crude protein yield and DM percentage and yield of the first crops after winter. 6. It may be concluded from the above results that three times as cutting frequency and Sept. 30 as the last cutting data were desirable for the DM yield, but four times as cutting frequency and Sept. 30 as the last cutting data for the crude protein yield.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.1
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• pp.13-20
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• 2012

In this study, the change pattern of hydrological response function as development has been observed. The target watershed was selected Tanbu sub-Basin in the Bocheong Basin. The applied channel networks are composed of 10 cases that are channel networks by strahler's ordering scheme and cases of all grids channel or the hillslope in basin. To each case of grid in basin, channel and hillslope drainage path lengths to outlet of basin are calculated, and hydrological response function was calculated by Nash Model. As results of this analysis, the peak discharge of hydrological response function is increased and peak time is shortened as development of channel networks. And based on statistical characteristics of hydrological response function, mean (lag time) and variance of travel time are reduced exponentially.