• 정보과학회 논문지
• /
• 제43권10호
• /
• pp.1131-1143
• /
• 2016

수십억 개 간선들로 구성된 대용량 그래프를 어떻게 효과적으로 압축할 수 있을까? 정점 재배치를 통해 인접 행렬의 0이 아닌 값들을 집중시키면 그래프를 효율적으로 압축할 수 있을 뿐 아니라 페이지랭크 등 여러 그래프 마이닝 알고리즘의 수행 속도를 개선할 수 있다. 최신 정점 재배치 기법인 SlashBurn은 실세계 네트워크의 멱법칙 특성을 활용하는 실세계 그래프에 효과적인 방법이다. 하지만 단일 머신 기반으로 설계되어 대용량 그래프에 대해 처리 속도가 현저히 느려지거나 적용이 불가능한 한계가 있다. 본 논문에서는 이러한 한계를 극복하기 위한 분산 SlashBurn을 제안한다. 분산 SlashBurn은 대규모의 정점 재배치 프로세스를 분산 처리하여 대용량 그래프를 기존 방법보다 훨씬 빠르고 확장성 있게 처리한다. 대용량 실세계 그래프들에 대한 실험 결과, 분산 SlashBurn은 단일 머신 SlashBurn보다 45배 이상 빠르게 동작하였고, 16배 이상 큰 그래프를 처리할 수 있었다.

• 한국방재학회:학술대회논문집
• /
• 한국방재학회 2008년도 정기총회 및 학술발표대회
• /
• pp.719-722
• /
• 2008

Forest management is done to keep ecological health of forest and to enhancement of its function. Nowadays, the abnormal climate and heavy rain happen frequently. Therefore, there are opinions that the thinning slash allowed in the mountain is flowed in rivers, which can influence in flood damage. This study, we grasp moving characteristics of thinning slash through field survey and achieved basic study about the effect of thinning slash on the discharge capacity of rivers and stream structure.

• The Korean Journal of Ecology
• /
• 제27권4호
• /
• pp.225-230
• /
• 2004

The impact of slash and burning on microbial biomass C, N and P in soils of semi-evergreen tropical deciduous forest were studied from February 1999 to January 2000. The experimental sites were located near Moreh town in the Chandel district of Manipur state (India) along the Indo-Myanmar border between 23° 49' N-24°28'N latitude and 93°45'E-94°16'E longitude. Microbial biomass C ranged from 319.50 ㎍ g/sup -1/ 905.50㎍ g/sup -1/ in the slash and burnt site and from 209.50 ㎍ g/sup -1/ to 708.80 ㎍ g/sup -1/ soil in the forest site. Microbial N ranged from 19.30 ㎍ g/sup -1/ to 99.45 ㎍ g/sup -1/ in the slash and burnt site and from 16.08㎍ g/sup -1/ to 88.90 ㎍ g/sup -1/ in the forest site. Microbial P varied from 10.90 ㎍ g/sup -1/ to 32.21 ㎍ g/sup -1/ in the slash and burnt site and from 2.50 ㎍ g/sup -1/ to 17.60 ㎍ g/sup -1/ in the forest site in different months throughout the year. Microbial biomass C, N and P were recorded to be higher in the slash and burnt site compared to the forest site The conversion of forest into slash and burnt site for agriculture - the traditional shilling cultivation practiced by tribal people in the north- eastern India leads to addition of large amount of organic matter in the soil thereby exhibiting higher values of microbial biomass C, N and P in the recent slash and burnt site than that of the forest site. Relationship between the soil moisture, soil organic C and microbial biomass C, N and P were found to be correlated significantly in both the sites.

• 한국산림과학회지
• /
• 제96권3호
• /
• pp.325-337
• /
• 2007

화전과 화전민은 일제의 강한 규제와 정리 계획, 해방 이후 토지개혁에도 불구하고 1970년대까지 지속적으로 증가했다. 본 논문에서는 강고하게 존재했던 화전과 화전민이 1974-1979년의 화전정리사업으로 완전히 사라지게 된 필요 충분조건을 살펴보고자 했으며, 그 결과는 다음과 같다. 첫째, 일제시대 이후 지속적으로 증가하던 농촌 인구와 최하층의 농가수가 1967년경을 정점으로 감소하면서 화전과 화전민 발생의 근본 원인이었던 토지에 대한 인구의 압력이 약화되었다(사회적 필요조건). 둘째, 1960년대 중반부터 본격화된 경제개발계획으로 1974년의 국민총생산과 정부예산이 1960년의 25배 수준이 되어 화전정리사업에 충분한 투자가 가능해졌다(경제적 충분조건). 셋째, 항공사진을 이용한 산림자원조사 기술의 발전과 도로 시설의 확대로 화전민의 은닉성이 제거되어 재모경(再冒耕)을 철저히 감시할 수 있게 되었다(기술적 충분조건).

• Journal of Forest and Environmental Science
• /
• 제35권3호
• /
• pp.150-158
• /
• 2019

Exotic conifer trees have been extensively planted in southern China because of their high apparent growth and yield. These fast-growing plantations are expected to persist as a considerable potential for temporary and long-term carbon sink to offset greenhouse gas emissions. However, information on the carbon storage across different age ranges in exotic pine plantations is often lacking. We first estimated the ecosystem carbon storage across different age ranges of exotic pine plantations in China by quantifying above- and below-ground ecosystem carbon pools. The carbon storage of each tree component of exotic pine (Pinus elliottii) increased significantly with increasing age in Duchang and Yiyang areas. The stem carbon storage except <10 years in Ji'an areas was the largest component among all other components, which accounts for about 50% of the total carbon storage followed by roots (~28%), branches (~18%), and foliage (~9%). The mean total tree carbon storage of slash pine plantations for <10, 10-20 and 20-30 years across three study areas was 3.69, 13.91 and $20.57Mg\;ha^{-1}$, respectively. The carbon stocks in understory and forest floor were age-independent. Total tree and soil were two dominant carbon pools in slash pine plantations at all age sequences. The carbon contribution of aboveground ecosystem increased with increasing age, while that of belowground ecosystem declined. The mean total ecosystem carbon storage of slash pine plantations for <10, 10-20 and 20-30 years across China was 30.26, 98.66 and $98.89Mg\;ha^{-1}$, respectively. Although subtropical climate in China was suitable for slash pine growth, the mean total carbon stocks in slash pine plantations at all age sequences from China were lower than that values reported in American slash pine plantations.

• 한국방재학회:학술대회논문집
• /
• 한국방재학회 2008년도 정기총회 및 학술발표대회
• /
• pp.153-156
• /
• 2008

Comparative analysis of forest fire danger rating on the forest characteristics of thinning area and non-thinning area on forest fire burnt area was studied in this work. To investigate the effect of thinning slash in forest fire, Gangneung-si Wangsan-myeon, Ulgin-gun Wonnam-Myeon, Samchok-si Gagok-Myeon, in which forest fire broke out, were selected. As a result that investigated forest fire danger ratio between thinning slash and non-thinning slash, leeward scorching ratio(36%), crown damage ratio(29%), mortality of branch at the former are higher than those at the latter, leeward scorching ratio of tree, where thinning slash is around, is 10%-20% higher than that of independent tree. So I estimate that thinning slash has a some effect on the intensity of forest fire. And the result to investigate damage of forest fire according to tree species shows that leeward scorching ratio of conifer is 5% higher than that of non-conifer, and mortality of branch of the former is 19% higher than that of the latter. It is considered that forest fire may affect directly to a tree trunk if it diffuse to piled thinning tree because there was no space between thinning trees and trees. Furthermore, it was found that re-ignition had a chance to occur due to lots of piled thinning trees.

• The Korean Journal of Ecology
• /
• 제23권6호
• /
• pp.435-438
• /
• 2000

Diameter distributions describe forest stand structure information. Prediction equations for percentiles of diameter distribution and parameter recovery procedures for the Weibull distribution function based on four percentile equations were applied to develop prediction system of even-aged slash pine stand structure development in terms of the number of stems per diameter class changes. Four percentiles of the cumulative diameter distribution were predicted as a function of stand characteristics. The predicted diameter distributions were tested against the observed diameter distributions using the Kolmogorov-Smirnov two sample test at the ${\alpha}$=0.05 level. Statistically, no significant differences were detected based on the data from 236 evaluation data sets. This stand level diameter distribution prediction system will be useful in slash pine stand structure modeling and in updating forest inventories for the long-term forest management planning.

• 한국산림과학회지
• /
• 제108권1호
• /
• pp.67-76
• /
• 2019

최근 국내 숲가꾸기 산물수집 및 목재수확에 있어 하베스터, 포워더와 같은 중대형 임업기계의 활용이 증대되고 있는 실정이며, 이에 따른 토양환경 피해 및 임지생산력 저하 등 환경적인 문제가 대두되고 있다. 본 연구는 하베스터와 포워더의 임내주행에 있어서 벌채부산물처리(무처리, $7.3kg/m^2$과 $11.5kg/m^2$) 및 주행횟수(하베스터 1회와 포워더 1~10회)에 따른 토양 깊이별(10, 20 및 30 cm) 토양 물리성 변화 및 토양 지표면 교란을 판단하기 위하여 토양밀도, 토양관입저항, 토양패임 등을 측정하였다. 연구결과 임업기계의 임내주행에 따른 토양용적밀도는 벌채부산물 무처리구에서 처리구($11.5kg/m^2$)와 비교하여 약 10~29 % 높게 나타났으며, 토양관입저항은 약 25~139 %까지 높게 나타나 벌채부산물 처리에 따른 토양답압 저감효과를 확인할 수 있었다(p<0.05). 또한 벌채부산물 처리구와 무처리구 모두에서 주행횟수가 증가함에 따라 토양용적밀도와 관입저항은 증가하는 것으로 나타났으며, 벌채부산물 처리구는 하베스터 1회, 포워더 5회까지 전체 토양답압의 92%가 발생되었고 무처리구에서는 하베스터 1회 포워더 1회까지 전체 토양답압의 84 %가 발생되는 것으로 나타났다. 이 연구결과를 바탕으로 향후 하베스터와 포워더를 이용한 단목수확작업을 설계할 시에는 토양환경피해 및 피해면적을 최소화하기 위하여 주행차로에 벌채부산물을 처리하거나, 지정 주행차로를 설계하는 것이 필요하다고 판단된다.

• 한국산학기술학회논문지
• /
• 제2권2호
• /
• pp.19-23
• /
• 2001

본 연구에서는 축산에서 발생하는 분료의 슬러지을 고체와 액체로 분류하는 장치를 개발하기 위한 논문이다. 필터의 재료는 농촌에서 쉽게 구할 수 있는 왕겨를 사용하였으며 제안한 고액 분리기의 성능을 실험적으로 도출하였고, 필터두께와 왕겨 입겨 입자크기 및 주입 압력에 따른 토출량으로 나타냈다. 이 연구에서 고액 분리기의 최적 설계조건을 구한 후 이를 토대로 왕겨를 이용한 고액 분리기의 성능을 평가한 결과 좋은 성능을 얻었다.

• 한국언어정보학회지:언어와정보
• /
• 제8권1호
• /
• pp.117-136
• /
• 2004

In this paper, we have proposed Auto- TSS, an automatic transcription module of three ambiguous symbols-period (．), colon (:) and slash (／)--using their linguistic contexts. Few previous studies have discussed the problems of ambiguities in reading those symbols into Korean alphabetic letters in order to improve the current Korean TTS (Text-To-Speech) systems. We have classified 9 different reading formulae of the three symbols, analyzed their left and right contexts, and investigated selection rules and distributions between the symbols and their contexts. Based on these linguistic features, 30 stereotyped patterns, 53 rules and 5 heuristics determining the types of reading formulae are investigated for Auto-TSS. This module works modularly in 4 steps. The pilot test was conducted with three test suites, which contain respectively 6,979, 3,491 and 2,450 morpheme clusters containing at least one of three ambiguous symbols and Arabic numeral(s). Encouraging results of 94.3%, 93.0%, 94.2% accuracy were obtained for the test suites. Our next phases are to develop a guessing routine for unknown contexts of the union symbols by using statistical information; to refine the proper nouns and terminology detecting module; and to apply Auto-TSS on a larger scale.