• Journal of the Korean Society for Precision Engineering
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• v.27 no.10
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• pp.61-68
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• 2010

In order to let the humanoid robot walk on the uneven terrains, the robot's foot should have the similar structure and function as human's. The intelligent foot should be made up of toes and heel. When it walks on the uneven terrains, the foot's sole senses the force and adjusts foot's position before robot losing his balance. In this paper, the force sensors of robot's intelligent foot for having the similar structure and function like human are developed. The heel 3-axis force/moment sensor and toe force sensors for humanoid robot's intelligent foot is developed, and the characteristic tests of them are carried out. As a result of characteristic test, the interference error of the heel 3-axis force/moment sensor is less than 2.2%. It is thought that the developed force sensors could be used to measure the reaction forces which is applied the toes and the heel of a humanoid robot.

• The Korean Journal of Ecology
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• v.12 no.4
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• pp.209-218
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• 1989

In order to elucidate the relationship among the several forest types in the green-sbelt nearby Seoul, the vascular plant species data collected preferentially from 52 stands were subjected to DCA (detrended correspondence analysis). Eight types of forests were arranged on the I/II plane fo DCA stand ordination, Quercus mongolica, Alnus hirsuta, Populus alba $\times$ glandulosa, Robinia pseudo-acacia, Pinus densiflora, Pinus koraiensis, Larix leptolepis and pinus rigida forest. Correlation analysis between the stand scores of DCA and environmental factors revealed that the axis I of DCA stand ordination implied the gradient of altitude, organic matter, total nitrogen and depth of A horizon. The axis II implied the gradient of total nitrogen and soluble phosphorus. The results of PCA (principal components analysis) by environmental data were in good agreement with that of DCA by floristic data. The recruitments of Quercus spp. Occurred in all kinds of forest types in the green-belt and their recruitments were closely related with altitutde: Quercus dentata in the foot. Quercus serrata in the midslope and Quercus mongolica in the uperslope of the mountain.

• Korean Journal of Environment and Ecology
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• v.16 no.3
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• pp.249-260
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• 2002

The cultivated lands in metropolitan, such as Seoul, are quasi-natural areas that have been disturbed continuously by human being and is in needs to be preserved and to be managed than to get more crop production in the light of nature experience for civilians through conservation of biodiversity and landscape diversity. However, the cultivated lands in urban areas have decreased rapidly, being changed into developmental areas in its land use. This study is to review change of land use as time change of the cultivated lands in Seoul and to draw the landscape ecological characteristics and structure in the cultivated land after their analysis on the basis of biotope type map in Seoul. The ultimate goal of this study is for development of prototype to enhance biodiversity in urban drypaddy culture area on the results of these analyses.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.288-288
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• 2010

현대사회의 급속한 고령화로 암 환자의 수는 2002년 기준 약 10만 명에서 매년 7~10 %씩 증가되어 2012년에는 20만 명이 될 것으로 추정되어지고 있다. 수술, 방사선 치료, 약물요법 등이 주요 치료방법이며, 암 환자의 30-50 %가 전리 방사선치료를 받고 있다. 방사선치료는 19세기 말에 발견된 미지의 X-선이 희망의 방사선으로 변화하여 암의 진단 및 치료에 활용되고 있으며, 인간 삶의 질 향상에 핵심적인 역할을 담당하고 있다. 기존의 X-선이나 감마선의 단점을 극복 할 수 있는 입자 빔을 1970년대 미국의 캘리포니아 대학 Berkely National Laboratory에서 처음으로 암 치료에 적용하였다. 현재는 일본과 독일에서 활발하게 활용되고 있으며 국내에서도 입자 치료시설을 구축 또는 개발계획 중에 있다. 방사선치료의 완치율을 높이기 위해서는 정확한 선량을 암세포에 전달해야 한다. 환자에 전달되는 입자빔을 실시간으로 측정하는 기술이 연구되어지고 있다. 지금까지는 빔의 특성을 측정하기 위해 간섭적인 방법을 사용하였으나, 투과형 검출기를 개발하여 실시간으로 치료와 빔 특성을 동시에 수행하는 기술개발연구가 보고되고 있다. 본 연구에서는 Multileaf Faraday Cup (MLPC) 검출기 설계구조와 데이터 측정방법에 관한 연구를 수행하고자 한다. 빔의 전송 방향으로 3개층의 $4{\times}4$ 배열의 구조로 48 channel의 전류값을 측정하여 입자빔의 분포를 실시간으로 관측하고, 측정된 전류는 ADC를 거쳐 치료계획에 의해 선택된 영역의 SOBP를 유지하도록 range modulation propeller를 조절하는 feed-back system을 갖춘 방사선치료빔 실시간 측정장치 개발에 관한 결과를 보고하고자 한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.396-396
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• 2019

습지는 가장 생산적인 생태계 중 하나이며, 인류에게 수문학적, 경제적, 문화적 가치로도 매우 귀중한 역할을 하고 있다. 하지만 기후변화와 인간의 영향으로 수위저하와 건조, 수문체계에 변화를 주어 습지의 건조화 현상이 나타나고 이로 인해 생태계에도 영향을 미치고 있다. 특히 산지습지는 인위적 간섭에 매우 취약하고 환경변화에 민감하여 불규칙한 강수패턴 및 무분별한 개발은 습지수문환경에 영향을 미쳐 습지의 건조화를 심화시키는 원인이 되고 있다. 그 결과 자연적으로 습지의 면적이 감소하고 식생의 패턴 변화로 다양한 생물들과 보호가 필요한 종들이 사라질 것이므로 변화에 대응하기 위해서 건조화를 방지할 필요가 있다. 따라서 본 연구에서는 습지 내 지하수위 저하 또는 유입 유출량의 변화로 습지 토양의 수분이 감소하여 말라가는 현상을 습지 가뭄이라 정의하고 가뭄지수를 활용하여 이를 지수화 하였다. 현재 산지습지를 대상으로 가뭄을 지수화 시킨 선행연구가 거의 없기 때문에 향후 산지 습지의 가치를 보존하고 생태계 관리의 목적으로 후속 연구의 방향을 제시하는데 도움을 줄 것으로 예상된다.

• Korean Journal of Plant Resources
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• v.30 no.2
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• pp.176-190
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• 2017

South Korea is the northernmost distributional territory on the Camellietea japonicae (evergreen broad-leaved forests of the warm-temperate zone) in East Asia. A total of 40 stands were collected in terms of an ecologically-naturalized wild tea population (WTP), and their species composition was analyzed by $Z{\ddot{u}}rich$-Montpellier School's method with preliminary regard to forest canopy idendtification. Stand types were characterized by ecological flora's criteria such as Raunkiaer's life-form, neophyte, zonal distribution, and nativeness of species. Expansion of WTP distribution into the interior of the peninsula was recognized, than expected. The highest and northernmost WTPs have been recorded at Mt. Palgong, Daegu (390 m a.s.l.) and Iksan Jeonbuk (latitude $36^{\circ}$ 03' 33''), respectively. Altitudinal and latitudinal WTP distribution of Korea under continental climate shows lower than Japanese situation under oceanic climate. Community structure generally involved a few human interferences. Syngeographically WTP distribution was limited on the warm-temperate zone and the southernmost cool-temperate southern submontane zone. First driving force on distributional expansion of the WTP was anthropogenic, particularly in the northernmost distribution area. We finally confirmed an actual existence of the WTP in South Korea and suggested a long-term monitoring on the WTPs in national view of in-situ genetic resources with higher frost-resistance.

• Korean Journal of Environment and Ecology
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• v.22 no.5
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• pp.505-513
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• 2008

The purpose of this study is to analyze the distribution patterns and characteristics of plant species by human impact in urban areas. In order to achieve a comprehensive data acquisition of all autogenously introduced vascular plant species occurring in the city of Cheon-ju, this study made an analysis of 106 sample plots, each with a size of one hectare, These sample plots were selected to represent the typical land-use patterns within the city of Cheon-ju and to cover the various distances from the city center. Species richness, patterns of life forms, and the percentage of non-native species were analyzed in relation to the degree of hemeroby of the sample plots. It was found that the species number appeared the largest in sites that were moderately influenced. This result corresponds to the intermediate disturbance hypothesis that moderate disturbance leads to an increase in species richness. The flora of sites which were subject to the highest level of human impact, was characterized by a high proportion of annual species and non-native species. In addition, some species were divided into three groups with similar distribution corresponding to land-use type and urban zone: urbanophobic (e.g. Indigofera kirilowii, Prunus sargentii, Rhus trichocarpa), urbanoneutral (e.g. Commelina communis, Erigeron annuus, Metaplexis japonica) and urbanophilus (e.g. Euphorbia supina, Senecio vulgaris, Taraxacum officinale).

• Korean Journal of Environment and Ecology
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• v.1 no.1
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• pp.46-65
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• 1987

This study was excuted to measure the user's impact area of the Bukhan Mountain National Park. Eighteen sites of the campsite and the picnic area were sample to measure the impact rating of soil and vegetation. And three belt transects were sampled to analyze soil properties and vegetational change by the user's impact. Also user's psychology was investigated through questionnaires with the visitor and 726 answers were collected from May to June in 1987. The regression equation was significant between the distance and the soil hardness. individual number per 100$m^2$, herb coverage and similarity index from the center of picnic area to the non-use site. The tolerant tree against user's impact are Lespedza maximowiczii. Stephanandra insica, Actinidia arguta Symplocos chinensis for. pilosa and the sensitive trees were Fraxinus rhy chophylla Sorbus alnifolia. and Rhodadendron mucronulatun. The facilities factor and social factor are the most affecting factors to User's psychology by the varimax rotated factor analysis. The carrying capacity of the picnic area was 25$m^2$ per man by the degree of psychological satisfaction.

• Journal of Environmental Policy
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• v.7 no.3
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• pp.141-160
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• 2008

The effects of disturbance on bird community were studied in Ssanggok Valley and Beopju Temple area, Songni Mt. National Park in $2006{\sim}2008$. We divided three sites by habitat condition such as traffic road(strong disturbance), trail(medium) and control(weak) site. During breeding and non-breeding seasons(n=12), number of species, number of individuals, species diversity and density did not differ among three sites, but in breeding season(n=9), number of species(Kruskal Wallis, $x^2$=10.32, p=0.006), number of individuals(Kruskal Wallis, $x^2$=7.118, p=0.028) and species diversity of birds(Kruskal Wallis, $x^2$=9.847, p=0.007) were significantly higher in trail site with medium disturbance than in other sites. In breeding season, nesting and foraging guild rate were not different among three sites. In guild analysis, hole was the highest nesting guild and canopy was the highest foraging guild in three sites.

• Korean Journal of Environment and Ecology
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• v.35 no.5
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• pp.558-568
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• 2021

Poor supervision and tourism activities have resulted in forest degradation in islands in Korea. Since the southern coastal region of the Korean peninsula was originally dominated by warm-temperate evergreen broad-leaved forests, it is desirable to restore forests in this region to their original vegetation. In this study, we identified suitable areas to be restored as evergreen broad-leaved forests by analyzing the environmental factors of existing evergreen broad-leaved forests in the islands of Jeollanam-do. We classified forest lands in the study area into six vegetation types from Sentinel-2 satellite images using a deep learning algorithm and analyzed the tolerance ranges of existing evergreen broad-leaved forests by measuring the locational, topographic, and climatic attributes of the classified vegetation types. Results showed that evergreen broad-leaved forests were distributed more in areas with a high altitudes and steep slope, where human intervention was relatively low. The human intervention has led to a higher distribution of evergreen broad-leaved forests in areas with lower annual average temperature, which was an unexpected but understandable result because an area with higher altitude has a lower temperature. Of the environmental factors, latitude and average temperature in the coldest month (January) were relatively less contaminated by the effects of human intervention, thus enabling the identification of suitable restoration areas of the evergreen broad-leaved forests. The tolerance range analysis of evergreen broad-leaved forests showed that they mainly grew in areas south of the latitude of 34.7° and a monthly average temperature of 1.7℃ or higher in the coldest month. Therefore, we predicted the areas meeting these criteria to be suitable for restoring evergreen broad-leaved forests. The suitable areas cover 614.5 km², which occupies 59.0% of the total forest lands on the islands of Jeollanamdo, and 73% of actual forests that exclude agricultural and other non-restorable forest lands. The findings of this study can help forest managers prepare a restoration plan and budget for island forests.