• 한국산림과학회지
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• 제99권6호
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• pp.827-835
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• 2010

기후변화협약 대응을 위한 산림의 임목축적량과 변화량 탐지의 측면에서 국가산림자원조사는 신뢰성있는 산림통계량을 산출하기 위한 기반자료로서의 결정적인 역할을 담당하고 있다. 그러나 많은 정보들이 아직 행정구역단위 통계로만 산출되고 있어 산림 통계량의 공간적 분포와 같은 정보를 제공해주지는 못하고 있다. 따라서 본 연구는 국가산림자원조사 자료를 이용해 임상특성별 임분재적 추정모델을 개발하고, 임상도와 통합하여 임분재적의 공간분포를 추정하는 것을 목표로 하였다. 산림의 임분재적 추정모델 개발을 위해 연구대상지에 포함된 국가산림자원조사 자료를 이용하여 표본점별 임분재적과 흉고단면적합을 산출하고, 표본점의 임황정보(수종, 경급, 영급, 소밀도)를 모델개발에 활용했다. 결과적으로 수종, 영급, 소밀도 기준에 따른 임분재적 모델이 구축되었으며, 본 모델을 임상도에 적용해 임분재적 주제도와 불확실성 주제도를 제작했다. 임분재적 주제도에 의한 연구대상지의 평균 임분재적은 85.7 $m^3$/ha이며, 95% 신뢰구간을 고려했을 때 약 79.7~91.8 $m^3$/ha 구간에 포함되는 것으로 나타났다.

• 한국환경복원기술학회지
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• 제11권3호
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• pp.1-11
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• 2008

Although landslides were frequently occurred under Tripterygium regelii and Rubus sp. vegetations, the damage of landslide was not observed in sasa (Sasa borealis) stands. These phenomena may be affected by forest vegetation types. This result suggested that the landslide occurred in Jirisan (Mt.) National Park may be closely related to water retention capacity at Sasa borealis stands. This study compared and analyzed the water retention capacity of each soil horizon of sasa, larch (Larix leptolepis) and mongolian oak (Quercus mongorica) stands. Soil bulk density in A horizon was lower in sasa (0.776g/$cm^3$) than in mongolian oak (0.828g/$cm^3$) and in larch stands (1.282g/$cm^3$). Water permeability in A horizon was 0.02055cm/sec for sasa, 0.00575cm/sec for mongolian oak, and 0.0007cm/sec for larch stands, respectively. The water permeability of sasa stand was about 3.6 times and about 29 times higher than in mongolian oak and in larch stands, respectively. This result indicates that water infiltration of soil surface during a rain event is more rapid in sasa than in other two stands. Soil organic matter content in B horizon was lower in larch (0.7%) than in mongolian oak (6.5%) and in Sasa (3.3%) stands. The solid ratio in A horizon was highest in larch among three stands, but that of mongolian oak and larch stands showed a similar rate. Pore space rates was 70.7% for A horizon and 70.6% for B horizon of sasa, 68.9% for A horizon and 70.6% for B horizon of sasa, 68.9% for A horizon and 70.6% for B horizon of mongolian oak forests and 51.7% for A horizon and 49.2% for B horizon of larch forests, respectively. According to pore space rates, the water retention capacity may be poor in larch stand compared with other two stands. Soil strength in sasa and mongolian stands was over 25kgf/$cm^2$ from 40cm depth, while the strength was over 25kgf/$cm^2$ from 25cm depth in larch stand. The result indicates that tree growth and water permeability in larch stand could be limited due to high soil strength. Larch stand was poor for soil pore space development to be offered to the water retention capacity, but water retention capacity of A horizon soil in sasa stand was high than that of other two stands. Therefore, establishment of sasa stand under larch stand could help to prevent landslides.

• Journal of Ecology and Environment
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• 제29권6호
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• pp.531-537
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• 2006

본 연구는 월악산 국가장기생태연구지소를 중심으로 이 지역에서 다른 개체군에 비하여 상대적으로 광역 우점하는 소나무림, 굴참나무림, 그리고 신갈나무림 등 3개 주요 임분을 대상으로 그들의 종조성과 구조적 특성을 평가하였다. 종 및 개체수는 분포 경향은 흉고직경급이 증가할수록 감소하는 경향을 나타내었으며, 종 풍부성에 있어서 다양한 입지 적응 폭을 가지고 있는 신갈나무림이 다른 두 임분에 비하여 상대적으로 높게 나타남을 알 수 있었다. 천이 경향은 임분별로 천이 단계상 다소 차이가 있지만 장기적으로 보면 임분 유형에 관계없이 모두 신갈나무림으로 변화될 것으로 판단되었다. 각 임분의 우점종을 기준으로 생목과 사목의 개체 밀도 구성비를 보면 신갈나무림에서 신갈나무 개체 75:25, 굴참나무림에서 굴참나무 개체 94:6, 그리고 소나무림에서 소나무 86:14로 신갈나무림에서 개체 고사율이 가장 높고 굴참나무림이 가장 낮게 나타났다. 이것은 각 임분의 천이 단계의 차이에 따른 종간 및 종내 경쟁의 결과로 판단되었다. 한편, 임분별 구성 개체목의 건강 상태를 보면 임분유형에 관계없이 AS형이 75$\sim$85%로 가장 높게 나타났으며 DF형은 전혀 나타나지 않았다. 끝으로 본 연구를 위해 설치한 영구 방형구는 향후 정기적인 조사를 통하여 이 지역 산림 생태계 보전에 적합한 유용 정보를 제공하여 줄 수 있을 것이다.

• 농업과학연구
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• 제30권2호
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• pp.139-147
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• 2003

The main purpose of this study is to obtain forest scenic beauty management informations toward forest working systems in pinus densiflora forest stands, etc. To get these information, visual preference and spatial image analysis methods are used. 25 different alternatives were simulated to visualize on basis of actual forest working methods with taken photos from May to July, 2003. The options were illustrated as photos produced by computer software. Respondents' ratings for 25 landscape scenes were obtained by interview survey method. Each alternatives were evaluated by forest major student group with total 103 respondents after reliability test. Visual preference evaluation was used 10 point rating scale. Spatial images of 12 alternatives were measured by 12 semantic differential scale. In general, the respondents preferred refreshing and ordering forest stand after forest working to natural forest stand before forest working. High visual preference for forest density produces 400-600 trees/ha in small diameter class forest stands. Regarding visual preference according to pavement type of trail, soil trail is ranked high. Visual preference for cutting area ranks mature forest stand and visual preference for trail slope cover type ranks shrub with grass as relatively high on the preference scale. Through the factor analysis, spatial images of 12 coniferous forest stands are classified as 'ordered opened' and 'beautiful healthy'. Results indicate how to conduct forest working systems for forest scenic beauty management.

• The Korean Journal of Ecology
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• 제16권3호
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• pp.329-339
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• 1993

Effects of relative light intensity and N, P fertilization on the growth and ramet dynamics of the rhizomatous plants, Arundinella hirta, Miscanthus sinensi and Spdiopogon sibiricus were studied in Chuncheon, Kangweon-Do. Ramets emerged in one pulse a year, withered in one pulse at the end of the growing season in M. sinensis and S. sibircus stands, while the birth and death pulse in A. hirta stands were two times. Total births of ramet were 9 times and 3.6 times greater in the unshaded fertilized stands of A. hirta and M. sinensis than in the shaded, However, those of S.sibiricus were 2.1 times greater in the shaded stands. Flowering rates of A. hirta, M.sinensis and S.sibiricus I the unshaded fertilized stands were 1.8, 2.7 and 1.04 times greater than in the shaded unfertilized stands, respectively. Height of ramets of A. hirta and M.sinensis were the hightest in the unshaded fertilized stands. However, that of s.sibiricus was the highest in the shaded fertilized stand. Aboveground production of A.hirta in the fertilized stand was 2.4 times greater in the unshaded stand than in the shaded one. Results of inflorescence frequency, shoot height and the ratio of aboveground to belowground were smiliar to the total births. The added fertilizer markedly increased the ramet density and the shoot productivity of three rhizomatous plants, especially of A. hirta.

• Journal of Forest and Environmental Science
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• 제36권1호
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• pp.7-16
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• 2020

Tree size distribution modelling is an integral part of forest management. Most distribution yield systems rely on some flexible probability models. In this study, a simple finite mixture of two components two-parameter Weibull distribution was compared with complex four-parameter distributions in terms of their fitness to predict tree size distribution of teak (Tectona grandis Linn f) plantations. Also, a system of equation was developed using Seemingly Unrelated Regression wherein the size distributions of the stand were predicted. Generalized beta, Johnson's SB, Logit-Logistic and generalized Weibull distributions were the four-parameter distributions considered. The Kolmogorov-Smirnov test and negative log-likelihood value were used to assess the distributions. The results show that the simple finite mixture outperformed the four-parameter distributions especially in stands that are bimodal and heavily skewed. Twelve models were developed in the system of equation-one for predicting mean diameter, seven for predicting percentiles and four for predicting the parameters of the finite mixture distribution. Predictions from the system of equation are reasonable and compare well with observed distributions of the stand. This simplified mixture would allow for wider application in distribution modelling and can also be integrated as component model in stand density management diagram.

• 전기전자학회논문지
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• 제23권3호
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• pp.826-831
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• 2019

소형 독립형 태양광 전원장치는 조명장치, CCTV 등에 많이 활용되고 있다. 이러한 장치가 경쟁력을 가지기 위해서는 배터리와 같은 전력저장장치 수명이 매우 중요하다. 하이브리드 커패시터는 고밀도와 장수명의 장점을 가지고 있다. 본 논문에서는 하이브리드 커패시터를 이용한 독립형 태양광 전원장치를 제안한다. 전력변환장치의 구성하기 위해 하이브리드 커패시터의 충방전 특성 및 내부저항을 측정하였다. 일사량 변화에도 안정적인 최대 출력점 추종제어 알고리즘을 제시하였다. 제시한 시스템의 타당성을 검증하기 위해 18W의 하이브리드 커패시터와 10W태양광 전지를 이용하여 시제품을 제작하고 실험하였다.

• 한국산림과학회지
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• 제87권2호
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• pp.173-178
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• 1998

야생 차나무집단의 임분구조와 현존량의 관계를 파악하기 위하여 지역, 위도 등을 고려하여 12개 야생 차나무 집단을 선정하여 임분구조와 현존량을 조사하였다. 차나무 집단별 평균 근원직경은 집단별 평균 수령과 유의적인 상관관계가 있었으나 집단별 평균 수고, 밀도, 근원단면적은 집단별 평균수령과 유의적인 상관관계가 없었다. 관목층인 차나무 집단의 밀도와 근원단면적은 교목층의 흉고단면적과 유의적인 상관관계가 없었다. 차나무의 표본목 측정 결과 근원직경이 증가함에 따라 줄기와 가지, 뿌리의 건중량은 지수함수적으로 증가하였으며, 1년생 잎과 소지의 건중량은 직선적으로 증가하였다. 2년생 이상 잎 건중량의 경우 근원직경과 상관관계가 없었다. 근원직경이 증가함에 따라 줄기와 가지, 뿌리의 건중량이 증가하는 것은 근주당 줄기의 수가 증가하기 보다는 좋기의 평균 직경과 수고가 증가하기 때문이었다. 차나무 집단의 임목 전체 현존량은 1,162~11,474kg/ha, 주 이용 대상인 1년생 잎의 현존량은 165~1,341kg/ha로서 집단간 큰 차이가 있었으며, T/R율은 1.5~2.8의 범위를 보였다. 축적기관인 줄기와 가지, 뿌리의 현존량은 평균 수령, 평균 근원직경, 밀도와는 독립적이었으나 근원단면적과 유의적인 상관관계가 있었다. 생산기관인 1년생 잎과 소지의 현존량은 평균수령, 평균 근원직경과는 독립적이었으나, 근원단면적, 밀도와 유의적인 상관관계가 있었다.

• Plant Resources
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• 제8권3호
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• pp.258-262
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• 2005

In autumn, to determine the optimal planting date and plant density of rapeseed in southern areas of Korea, Yudal variety for autumn sowing, the highest yielding variety was grown under three different planting dates and five different plant densities. Yield components such as plant height, ear length, number of seedling stand per $m^2$, number of branches and pod length were highest at the plots with Sep. 30 of planting date and 30/20 cm drilling of plant density. Yield of seed, oil and 1,000 grains weight were highest at the Sep.30 of planting date and 30/20 cm drilling of plant density. Judging from the results reported above, at optimum planting date and plant density of rapeseed seemed to be Sep.30 of planting date and 30/20cm plant density in autumn sowing.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권3호
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• pp.253-257
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• 2005

By using a coupled circuit, time-stepping, two-dimensional finite element method (2-D FEM), the performance of a stand-alone permanent-magnet synchronous generator (PMSG) with inset rotor can be computed without involving the classical two-axis model. The effects of interpolar air gap length and armature resistance on the load characteristics are investigated. It is shown that the interpolar flux density, and hence the amount of voltage compensation, is affected by magnetic saturation. Validity of the coupled circuit and field analysis is confirmed by experiments on a prototype generator. The machine exhibits an approximately level load characteristic when it is supplying an isolated unity-power-factor load.