• Journal of Forest and Environmental Science
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• 제33권3호
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• pp.172-186
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• 2017

The effects of application of fuel-reduction treatment in wildfire management has not been tested in dry forests of Ghana. Therefore, the short-term ecological effects of prescribed burning and hand thinning treatments followed by experimental wildfire were investigated in degraded forests and Tectona grandis forest plantations in two forest reserves of different levels of dryness in Ghana. The results showed that more trees were killed in prescribed burning (average of 41% in degraded forest and 18% in plantations) than hand thinning (7.2% in degraded forests and 8% in plantation). More tree seedlings were also killed in prescribed burning (72%) than hand thinning (47%). The mortality of trees and seedlings were greater in Worobong South forest, a less dry forest reserve than the Afram Headwaters forest, a drier forest reserve. Fuel treatment especially prescribed burning compared to the control reduced wildfire effects on forest canopy particularly in the less dry forest and tree mortality especially in the drier forest. Prescribed burning temporarily increased pH, exchangeable potassium (52%) and available phosphorus (82%) in the surface soils of the entire plots. The two fuel treatment methods did not have much influence on basal area, organic matter and total nitrogen. Nevertheless, they were able to reduce the adverse wildfire effects on soil pH, exchangeable potassium, available phosphorus, organic matter and total nitrogen concentrations. Fuel treatments therefore have potential application in dry forest management in Ghana due to their ability to retain important forest ecological traits after a wildfire incidence.

• 한국토양비료학회지
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• 제44권3호
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• pp.502-509
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• 2011

해안매립지에서 식재지반 조성을 위한 복토높이에 따른 토양의 채취, 운반 및 매립에 소요되는 비용이 매우 큰 차이가 있기 때문에 수목의 정상생육이 가능한 적정 복토높이를 구명하는 것은 매우 중요하다. 본 연구는 아산국가산업단지에서 해송, 화백, 느티나무 및 상수리나무에 대하여 복토처리별 (대조구, 0.5 m, 1.0 m, 1.5 m, 2.0 m 복토구) 로 식재 후 2년 6개월 경과한 후 토양화학성, 수목 고사율, 수고 및 근원경 생장의 변화를 조사하였다. 토양화학성은 복토높이가 낮을수록 pH, EC, 염기총량 및 염기포화도가 높아지고 $K^+$, $Na^+$, $Ca^{2+}$, $Mg^{2+}$, $Cl^-$ 등 염류함량이 증가하였다. 특히 1 m 복토구 이하에서 이들 화학성분의 농도가 높아져, 수목의 고사율 및 생장에 직접적인 영향을 준 것으로 나타났다. 수목 고사율은 복토높이가 높을수록 낮아지는 경향이 있었으며, 1.5 m 복토구 미만에서 고사율이 급격히 증가하였다. 수고와 근원경 생장은 복토처리가 높을수록 양호하게 나타나는 경향이 있었다. 수고생장은 해송의 경우 0.5 m 복토구와 나머지 3개 처리 간에 유의적인 생장차이가 있었으며 화백, 느티나무, 상수리나무는 1.5 m 복토구 미만에서 유의적인 생장차가 있었다. 근원경의 경우 식재수종 모두 복토높이가 높을수록 생장이 양호하였으며 1.5 m 복토구와 2.0 m 복토구 간 생장차이가 없었다. 본 연구결과에 따르면 해안매립지의 복토높이에 따른 고사율 및 생육특성은 식재수종에 따라 차이가 있으며 해송의 경우 1 m 이내의 복토도 가능한 반면에 화백, 느티나무 및 상수리나무는 1.5 m 이상 복토가 필요할 것으로 보인다.

• Journal of the Korean Data and Information Science Society
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• 제22권3호
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• pp.389-400
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• 2011

본 연구의 목적은 행정자료를 이용하여 지역사회획득 폐렴 환자의 사망 요인을 분석하기 위해 수행되었다. 2004~2006년 퇴원손상환자 조사자료 중 지역사회획득 폐렴환자 5,353건을 연구대상으로 하였으며, 사망률의 차이분석은 카이제곱 검정을 실시하였고, 사망 요인을 분석하기 위해 데이터마이닝 기법 중 의사결정나무 모형을 이용하였다. 의사결정나무 모형 중 C4.5가 성능이 우수하였는데, 입원경로, 호흡부전, 울혈성심부전을 포함하여 연령, 동반질환, 병상규모 등이 폐렴 사망의 위험 요인으로 나타났다. 본 연구는 행정데이터를 이용하여 지역사회획득 폐렴환자의 사망 위험요인을 밝히고자 하였다. 그러나 향후 병원특성, 지역특성, 의료행태 등에 대한 보다 포괄적인 변수를 포함한 후속 연구가 필요할 것으로 생각된다.

• The Korean Journal of Ecology
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• 제15권1호
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• pp.19-33
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• 1992

The density, litterfall, phytomass, and primary productivity for 7 years in quercus mongolian forest locasted at mt. nambyengsan, pyeongchang-gun, gangwon provance in central part of korean peninsula were estimated quantitatively. at the first year in 1984, a stand had 1, 450 trees/ha in tree density, which was 0.67 of skewness and 0.54 of kurtosis in frequency distribution, however, at the 7th year in 1990, the stand had 1, 133 trees/ha in the density with 22%(or 316 tree/ha)in mortality, which was 1.16 of skewness and 1.89 of kurtosis in the frequency. annual mean litterfall was 5 ton DM/ha, which was composed of 68% of leaves, 17% of branches, 3% of bud scales, 9% of arcons and cups, 0.7% of flowers and others. the phytomass of tree layer for 7 years was gradually increased from 149.7 ton DM/ha at the first year to 188.5 ton DM/ha at the 7th year.annual net productivity for the tree layer studied ranged from 8.76 ton DM/ha.yr-1 to 11.62 ton DM/ha. yr-1 with heavy fluctuation year by year. average annual productivity of the stand of trunk, branches, leaves and roots for 7 years were 4.42, 0.67, 3.85 and 1.29 ton DM/ha.yr-1, respectively. turnover rate of the stand was 6.9% at the first year and 5.6% at the 7th year. such fluctuation of the productivity was caused by the chang of density, mortality, mortality and turnover rate.

• 한국산림과학회지
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• 제100권1호
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• pp.1-7
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• 2011

본 연구는 기존의 잣나무임분 거리독립 개체목 생장모델을 개선하기 위해 수행되었다. 직경생장함수 및 고사율함수의 매개변수들을 고정표본점의 정기평균생장량을 토대로 추정하고, 이 함수들의 특성을 기존의 총평균생장량을 토대로 추정한 모델과 비교하였다. 여기서 생장함수는 수관율함수, 잠재직경생장함수 및 임분을 구성하는 임목간 경쟁효과를 고려하기 위한 수정율함수를 의미한다. 고사율예측함수의 경우에는 고정표본점 자료의 한계로 인해 정기평균생장량 측정값을 구할 수 없어 대신 총평균생장량과의 관계식을 추정하여 대체하여 적용하였다. 연구결과 정기평균생장량을 토대로 하는 직경생장함수가 총평균생장량을 토대로 추정한 함수에 비해 개체목의 생장특성을 보다 현실적으로 반영하는 것을 보여주었다. 고사율함수의 경우, 총평균생장량을 적용하여 개발한 경우 고사율이 과대한 것으로 나타나는 문제가 있었으나 새로운 모델에서는 이 문제가 개선된 것으로 나타났다.

• Journal of Forest and Environmental Science
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• 제30권3호
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• pp.301-306
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• 2014

A study was carried out to identify the life cycle of Adoxophyes orana (Lepidoptera: Tortrididae) that inflicts tea tree leaves in Korea and selected three ecofriendly pesticides (Common name for commercial: Essential oil, Nemacatch, and Wormstop in Korean Farmers' Market) of A. orana for pest control. A. orana appeared to follow four life cycle phases a year; each presenting varying developmental periods dependent on seasonal and environmental factors. The fecundity of A. orana female was $24.6{\pm}4.10$ for $1^{st}$, $36.7{\pm}12.77$ for$ 2^{nd}$, and $27.9{\pm}4.22$ for $3^{rd}$ phase during 2011, while it was $65.0{\pm}32.72$, $49.7{\pm}30.27$, $63.8{\pm}27.22$ for corresponding phases during 2012. The average longevity of adult A. orana was 7.72 days. The average number of eggs deposited by each female in this study group was 44.62 with an average of 2.47. In three selected ecofriendly pesticides, the mortality of A. orana on treating with the Essential oil [The essential oil of Chamaecyparis obtuse (100%)] and Nemacatch [Azadirachtin 800-900 ppm (75%)] were 36.67% and 43.33% after 3 days and were 48.30% and 56.67% after 7days, respectively. Besides, the mortality of A. orana on treating with Wormstop [Azadirachtin 500 ppm (5%) and Salannin+Liminoids (95%)] was 61.67% and 78.33% after 3 and 7 days, respectively. Therefore, the application of Wormstop was the most useful to control the diseases caused by A. orana.

• 디지털융복합연구
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• 제13권12호
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• pp.245-257
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• 2015

본 연구는 복합만성질환 입원환자를 대상으로 중증도 보정 사망 예측모형을 개발하고, 중증도 보정 사망비의 변이 요인을 규명하여 변이를 줄일 수 있는 방안을 제시하고자 하였다. 이를 위해 퇴원손상심층조사 자료 2008년부터 2010년까지 자료를 수집하고 주진단이 만성질환이면서 주진단을 포함하여 2개 이상의 만성질환을 보유한 30세 이상의 복합만성질환 입원환자 110,700건을 최종 연구대상으로 선정하였다. 예측 모형 개발 시 데이터마이닝 기법(로지스틱회귀분석, 의사결정나무, 신경망 기법)을 적용하였다. 본 연구에서는 Elixhauser comorbidity index 동반상병 보정지수를 이용하여 의사결정나무분석으로 복합만성질환 입원환자의 중증도 보정 사망 예측모형을 개발하였다. 복합만성질환 입원환자의 의료기관 중증도 보정 사망비(HSMR)를 산출 한 결과 진료비 지불방법별, 병상규모별, 의료기관소재지별로 통계적으로 유의한 차이가 있는 것으로 나타났다. 상기 분석결과를 바탕으로 국가적 차원에서 복합만성질환 입원환자의 사망비를 효율적으로 관리하여 의료의 질 향상과 증가하는 의료비 부담 감소를 위해 지속적인 관심과 노력을 기울여야 할 것이다.

• Journal of Ecology and Environment
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• 제44권4호
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• pp.241-255
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• 2020

Background: The stem exclusion stage is a stage of forest development that is important for understanding the subsequent understory reinitiation stage and maturation stage during which horizontal heterogeneity is formed. Over the past 11 years (2009-2019), we observed a deciduous broad-leaved forest in the Albongbunji Basin in Ulleungdo, South Korea in its stem exclusion stage, where Fagus engleriana (Engler's beech) is the dominant species, thereby analyzing the changes in the structure (density and size distributions), function (biomass and species richness), and demographics. Results: The mean stem density data presented a bell-shaped curve with initially increasing, peaking, and subsequently decreasing trends in stem density over time, and the mean biomass data showed a sigmoidal pattern indicating that the rate of biomass accumulation slowed over time. Changes in the density and biomass of Fagus engleriana showed a similar trend to the changes in density and biomass at the community level, which is indicative of the strong influence of this species on the changing patterns of forest structure and function. Around 2015, a shift between recruitment and mortality rates was observed. Deterministic processes were the predominant cause of tree mortality in our study; however, soil deposition that began in 2017 in some of the quadrats resulted in an increase in the contribution of stochastic processes (15% in 2019) to tree mortality. The development of horizontal heterogeneity was observed in forest gaps. Conclusions: Our observations showed a dramatic shift between the recruitment and mortality rates in the stem exclusion stage, and that disturbance increases the uncertainty in forest development increases. The minor changes in species composition are likely linked to regional species pool and the limited role of the life-history strategy of species such as shade tolerance and habitat affinity. Our midterm records of ecological succession exhibited detailed demographic dynamics and contributed to the improvement of an ecological perspective in the stem exclusion stage.

• 한국환경복원기술학회지
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• 제14권2호
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• pp.1-10
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• 2011

Six pine trees (Pinus densiflora S. et Z.) at the Euilimji Lake Park in Jecheon were collected to investigate tree ages, growth decline pattern and the years of death. Tree-ring measurement was carried out using the Lintab with a resolution of 0.01mm. Tree age were 80-176 years. Cross-dating between the tree-ring series of each tree and the local chronology from Worak Mountain resulted that four and two trees died in 1998 and 1999, respectively. Three dead trees had only formed earlywood in the outermost tree ring and the others had incomplete latewood. Therefore, it was proven that the former trees died between spring and early summer, whereas the later ones died during late summer and/or autumn. The simultaneous deaths of trees suggest the insect damage and/or drought may be the crucial reason of the death, but frequent reaction woods, which were formed by leaning stem, and scars formed by physical damage may also contribute to the death.

• International Journal of Advanced Culture Technology
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• 제5권3호
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• pp.40-45
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• 2017

This data mining technique was used to extract useful information from percutaneous coronary intervention data obtained from the US public data homepage. The experiment was performed by extracting data on the area, frequency of operation, and the number of deaths. It led us to finding of meaningful correlations, patterns, and trends using various algorithms, pattern techniques, and statistical techniques. In this paper, information is obtained through efficient decision tree and cluster analysis in predicting the incidence of percutaneous coronary intervention and mortality. In the cluster analysis, EM algorithm was used to evaluate the suitability of the algorithm for each situation based on performance tests and verification of results. In the cluster analysis, the experimental data were classified using the EM algorithm, and we evaluated which models are more effective in comparing functions. Using data mining technique, it was identified which areas had effective treatment techniques and which areas were vulnerable, and we can predict the frequency and mortality of percutaneous coronary intervention for heart disease.