• 동력기계공학회지
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• 제11권3호
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• pp.22-28
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• 2007

Liquefied gas vaporizer is a machine to vaporize liquefied gas such as liquid nitrogen($LN_{2}$), liquefied natural gas(LNG), liquid oxygen($LO_{2}$) etc. For the air type vaporizer, the frozen dew is created by temperature drop (below 273 K) on vaporizer surface. The layer of ice make a contractions on vaporizer. The structure analysis on the heat transfer was studied to see the effect of geometric parameters of the vaporizer, which are length 1000 mm of various type vaporizer. Structure analysis result such as temperature variation, thermal stress and thermal strain have high efficiency of heat emission as increase of thermal conductivity. As the result, Frist, With-fin model shows high temperature distribution better than without-fin on the temperature analysis. Second, Without-fin model shows double contractions better then with-fin model under the super low temperature load on the thermal strain analysis. Third, Vaporizer fin can be apply not only heat exchange but also a stiffener of structure. Finally, we confirm that All model vaporizer can be stand for sudden load change because of compressive yield stress shows within 280 MPa on thermal stress analysis.

• 한국산림과학회지
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• 제97권5호
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• pp.501-507
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• 2008

The data of crown width with 4 directions, DBH, tree height, and coordinate for sample trees were collected from 30 permanent sample plots in secondary fore st of the Maoershan Experimental Forestry Farm, Northeast China. In this paper, the competition of individual trees in stand were discussed for secondary forest by using iterative Hegyi competition index and crown overlap index that represented the competitive and cooperative interactions among neighboring trees. Active competitors of subject tree in the competition zone were selected to calculate the iterative competition index. Using the results of crown classification based on the equal crown projection area, a new distance dependent competition index called crown overlap index (COI) was developed for secondary forest. The COI performed well in describing the crown competition rather than crown competition factor (CCF). The individual-based competition index discussed in this paper will provide more precise for developing individual tree growth models for secondary forest and it can also use to adjust the stand structure for spatial optimal management.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.512-514
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• 2005

Accurate DEM surface of forest floor is very important to extract any meaningful information regarding forest stand structure, such as tree heights, stand density, crown morphology, and biomass. In airborne lidar data processing, DEM data of forest floor is mostly generated by interpolating those elevation points obtained from last laser returns. In this study, we try to analyze the property of the last laser return under relatively dense forest canopy. Airborne laser data were obtained over the study area in relatively dense pine plantation forest. Two DEM data were generated by using all the points in the last laser returns and using only those points after removing non-ground points. From the preliminary analysis on these DEM data, we found that more than half of points among the last laser returns are actually hit from canopy, branches, and understory vegetation that should be removed before generating the surface DEM data.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2002년도 가을 학술발표논문집 Vol.29 No.2 (1)
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• pp.268-270
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• 2002

오늘날 급속하게 발전하는 유전자 분석기술은 유전자 서열(sequence), 단백질의 기능(function) 및 구조(structure)정보와 같은 생명현상의 연구에 필수적인 정보들을 제공하게 되었다. 특히, 인간 유전체 프로젝트의 완성 이후 염기 및 단백질의 서열데이터를 이용하여 유사한 서열데이터의 검색 및 관련 단백질의 기능, 구조 정보들과 같은 생물정보의 종합적인 검색이 요구되고 있다. 하지만 기존 대부분의 통합서열분석시스템들은 단지 관련 정보를 포함하는 데이터 베이스들에 접근하며 서열유사성을 분석한 후, 그 결과를 단순히 디스플레이 하는 것이 대부분 이였다. 부연하면, 기존 통합 서열분석시스템들은 각 데이터베이스로부터 검색된 결과들 간의 명확한 관계를 설명하지 못하여 종합적인 생물정보를 제공하지 못하고 있다. 따라서 본 논문에서는 염기 및 단백질의 서열데이터로부터 서열유사성 검색 및 관련 단백질의 기능, 구조정보에 해당하는 종합적 인 생물정보를 효과적으로 검색, 서비스 할 수 있는 통합 서열분석시스템의 설계, 구현에 관해 기술한다.

• Journal of Forest and Environmental Science
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• 제29권3호
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• pp.219-225
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• 2013

The correlation between disturbance intensity and stand development was evaluated on the basis of natural forest community type classification in areas of Baekhaksan (more disturbed area) and Hwangaksan (less disturbed area). The vegetation data were collected by point-centered quarter sampling method, and they were subjected to cluster analysis for classifying community types and to analysis of species composition and species diversity for reviewing ecological characteristics. By the method of cluster analysis, natural forests of Baekhaksan were classified into Quercus forest community, Pinus densiflora community, Q. variabilis community, and Q. mongolica community. Those of Hwangaksan were divided into P. densiflora community, Q. mongolica community, Q. forest community, and Mixed mesophytic community. It is presumed that more developed and less disturbed forest area shows multiple species community pattern and more diversified structure than less developed and more disturbed forest area. In Korean peninsula, the abundance of red pine may play an important indicator to estimate the developmental pattern of the forest after artificial disturbance. The overall evaluation indicated that less disturbed Hwangaksan area had more developed stand pattern with mixed mesophytic community, more complicated species composition, and higher species diversity than Baekhaksan area.

• Journal of Plant Biology
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• 제33권3호
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• pp.173-182
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• 1990

To investigate the structure of the plant community structure of Mt. Yongmun in Kyonggi-do, fifty-four plots were set up by the clumped sampling method. The classification by TWINSPAN and DCA ordination were applied to the study area in order to classify them into several groups based on woody plant and environmental variables. By both techniques, the plant community were divided into two groups by the aspect. the dominant species of south aspect were Pinus densiflora, Quercus aliena, Q. mongolica, Carpinus laxiflora and of north aspect were Q. ongolica, Fraxinus rhynchophylla. The successional trends of tree species in south aspect seem to be from P. densiflora through Q. serrata, Q. aliena, A. mongolica to C. laxiflora. As a result of the analysis for the relationship between the stand scores of DCA and environmental variables, they had a tendency to increase significantly from the P. densiflora and Q. mongolica community to C. laxiflora and F. rhynchophylla community that was the soil moisture, the amount of soil humus and soil pH.

• 한국환경과학회지
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• 제23권3호
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• pp.335-357
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• 2014

This study aims at classifying and interpreting on the vegetation structure and the vegetation transition over 25 years (between 1986 and 2010), and the correlation with the change of some conditions (the vegetation height and coverage on each layer and the climate factors as WI, CI, mean annual temperature, mean annual total precipitation etc.) in the Evergreen Broad-Leaved Forest,, Hong-Do island. The EBLF is classified into five units of vegetation (Hedera rhombea-Machilus thunbergii community (M-M comm.), Castanopsis sieboldii forest (Machilus japonica-Castanopsis sieboldii community; Raphiolepis indica var. umbellata-C. sieboldii community), community (Qa comm.), Carpinus turczaninovii community (Ct comm.), Camellia japonica stand (Cj stand)). The vegetation transition by CCA had high correlation with the height and coverage on each layer and the climate factors, and it did the succession (transition) that the M-M comm. (2010) from Mallotus japonicus community Machilus thunbergii community Carpinus coreana community (Cc comm.) Aucuba japonica community (Aj comm.) Trachelos permum asiaticum var. intermedium-Quercus acuta community (TQ comm.) (1986), the communities of C. sieboldii forest (2010) from Aj comm. TQ comm. Raphiolepis umbellata-Camellia japonica community (RC comm.) (1986), the Qa comm. (2010) from Ardisia japonica-Castanopsis sieboldii community (AC comm.) and TQ comm. (1986), the Ct comm. (2010) from Cc comm. RC comm. Aj comm. Quercus serrata community and the Cj stand (2010) from AC comm. (1986). the height and coverage on each layer are also changed.

• Journal of Forest and Environmental Science
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• 제33권1호
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• pp.66-73
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• 2017

This study was conducted to evaluate the ecological attributes of forest types which were classified by cluster analysis in the natural forest of Mt. Odae on the basis of the vegetation data (232 sampling points) from the point-quarter sampling methods. For the classified types, the species composition was expressed by importance value to describe the stand structure and the species diversity was quantified using the Shannon's diversity index. Recognized forest types were 1) Quercus mongolica-Pinus densiflora-Betula ermanii forest type, 2) Mixed mesophytic forest type, 3) Q. mongolica forest type, 4) B. ermanii forest type. Species diversity indices of total and overstory were highest in the Mixed mesophytic forest type (3.465 and 2.942), and lowest in the B. ermanii forest type (0.118 and 0.832). In addition to that, Q. mongolica-P. densiflora-B. ermanii forest type was calculated as 3.226 and 2.565, and Q. mongolica forest type was calculated as 2.776 and 1.218 in total and overstory, respectively. It was considered that after the P. densiflora and B. ermanii first invaded and site condition became good, Q. mongolica-P. densiflora-B. ermanii forest type was dominated by Q. mongolica. Mixed mesophytic forest type showed the most stable stand structure with various species distributed uniformly. Q. mongolica forest type would preserve the present stand status for a while, and the B. ermanii in B. ermanii forest type would be pressed by other species over time.

• 한국산학기술학회논문지
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• 제14권11호
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• pp.5334-5337
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• 2013

본 논문에서는 도심 미관의 보완을 위해 와이어를 제거한 교통신호등의 구조 해석을 수행한다. 실제 교통신호등의 3차원 CAD 모델로부터 쉘 요소로 이루어진 유한요소 모델을 생성하였고, 특히 교통신호등의 지주 및 가로재는 모양, 두께, 보강재 등을 고려하였다. 풍하중을 적용하여 응력 및 변형 해석을 수행하였으며, 풍하중이 적용될 경우에 교통신호등에 미치는 결과를 분석하여 설계 개선에 대한 기본 작업을 수행하였다.

• 한국농림기상학회지
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• 제17권3호
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• pp.207-216
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• 2015

본 연구는 산불 피해지에서 복원 방법 및 수종의 구성에 따라 미세 기후가 어떻게 변하는지에 관한 연구는 거의 이루어진 바 없어 산불 피해지에서 복원 방법 및 임분의 구성에 따라 임분 내 기상 패턴이 어떻게 변화하는지에 대해 구명하고자 수행되었다. 본 연구에서 사용된 독립 변수로 임분을 구성하는 수종의 종류와 생장, 임분 밀도, 그리고 피복율이며, 이에 따른 종속 변수로는 임분 내 광량, 기온, 습도, 토양 온도, 그리고 토양 수분 함량이었다. 기상 조건은 대부분 광 조건에 영향을 받는 종속 변수이나, 임분을 구성하는 수목의 생장과 피복률에도 변화하는 것으로 나타났다. 임분 내 습도는 임분 밀도와, 임분 내 기온과 수목의 수고와 음(-)의 상관 관계에 있는 것으로 나타나 임분 밀도와 수목의 생장이 증가할수록 임분 내부의 기온과 습도는 상대적으로 감소하는 경향을 보였다. 그러나 임분의 발달은 대부분 미세 기후의 전체 평균보다는 변동계수와 같은 편차를 줄이는 형태로 더 큰 영향을 주었으며, 수관 층의 수고와 임분 내 광량과 직접적인 관계에 있는 것을 감안하면($R^2$=0.87), 임분의 구조는 광량에는 직접적인 영향을, 다른 미세 기후에는 간접적인 영향을 준 것으로 사료된다. 한편 변동계수의 경우 삼척 지역이 고성 지역보다 상대적으로 높은 값을 보였으며, 수목의 생장에 따라 감소하는 경향을 보였다. 따라서 산불 발생 이후 시간 경과에 따라 상대적으로 안정된 상태를 지니는 것으로 해석되었다. 그러나, 현재 단계에서는 산불 피해 이후 숲의 발달에 따른 임분 내부의 기상 조건의 변화상을 뚜렷하게 확인하고 일반화하기에는 많은 어려움이 있어 이를 위해서는 보다 긴 시간에 걸쳐 많은 지점에서의 기상 조건과 임분 현황을 지속적으로 조사되어야 할 것이다. 이후 일반화된 자료를 활용한다면, 임분 구조와의 관계 해석은 물론, 하층 식생 출현 등에 대한 해석에 도움이 될 것으로 기대된다.