• Title/Summary/Keyword: 평균 모델

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Harvesting Cost of Tree-length Thinning in a Larix leptolepis Stands (낙엽송 간벌작업에서 전간수확시스템의 작업비용 분석)

  • Cho, Koo-Hyun;Cho, Min-Jae;Han, Han-Sup;Han, Sang-Kyun;Cha, Du-Song
    • Journal of Korean Society of Forest Science
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    • v.104 no.2
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    • pp.221-229
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    • 2015
  • The purpose of study was to broaden our knowledge on the productivity and cost of thinning operations which has become increasingly practiced in Korea. The thinning operations were conducted in a 40-year old larch (Larix leptolepis) stand, including chainsaw felling and processing at the stump, followed by yarding tree-length logs using a Koller K301-4 tower yarder. The logs were further processed and sorted into 1.8 m and 3.6 m log piles at the landing. We used a standard time study method to evaluate key variables that affect the productivity of thinning operations. The total stump-to-pile operational cost was $41,707won/m^3$. The highest cost activity was the yarding phase which cost $20,083won/m^3$ (48.2% of the total cost), followed by the costs of processing treelength materials into marketable log lengths ($12,143won/m^3$; 29.1%), and then by the costs of sorting/piling the processed logs ($5,039won/m^3$; 12.1%). It was interesting to see that felling and processing trees at the stump had low costs at $1,315won/m^3$ (3.2%) and $3,127won/m^3$ (7.5%), respectively. We used the detailed time study data to develop regression equations which were to predict yarding productivity. Our analysis showed that harvesting system cost was highly sensitive to the number of logs, yarding distance and lateral distance per turn, respectively.

Optimal Production Management Strategy for Non-timber Forest Products using Portfolio Approach - A case study on major fruit trees - (포트포트폴리오 기법을 이용한 단기소득임산물의 최적 생산관리 전략 - 주요 유실수를 중심으로 -)

  • Won, Hyun-Kyu;Jeon, Jun-Heon;Lee, Seong-Youn;Joo, Rin-Won
    • Journal of Korean Society of Forest Science
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    • v.104 no.2
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    • pp.248-253
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    • 2015
  • This study applied the portfolio approach as a means to provide decision-making information for the establishment of the optimal production plan for non-timber products. The target items of non-timber forest product were Chestnut, Jujube, Walnut and Astringent Persimmon. The data used in this study were the annual report of forestry production cost survey which contains the annual production, annual gross income, and annual product cost from 2008 to 2013. These data were used to calculate the expected return of non-timber forest product. The objective function in the portfolio models was to minimize the expected return volatility, called risk and the constrain was to achieve the minimum expected return rate. Results indicated that the production ratio of the nuts and fruits in 2013 was 7% for Chestnut, 20% for Jujube, 5% for Walnut and 68% for Astringent Persimmon. Furthermore, portfolio presented that the production ratio was 10% for Chestnut, 9% for Jujube, 3% for Walnut and 78% for Astringent Persimmon in the near future. The cause was analyzed due to maintain stable production and income of Astringent Persimmon and Chestnut. Meanwhile, the revenue of Walnuts and Jujube was in great variation with relatively higher revenues.

Electrical Resistivity of Cylindrical Cement Core with Successive Substitution by Electrolyte of Different Conductivity (전도성이 다른 공극수로 순차 치환한 시멘트 시험편의 전기비저항)

  • Lee, Sang-Kyu;Lee, Tae-Jong
    • Geophysics and Geophysical Exploration
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    • v.12 no.4
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    • pp.328-337
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    • 2009
  • To investigate the relation between pore fluid conductivity and bulk resistivity of a rock sample it is assumed that electrolyte solution perfectly substitute the pore fluid that occupied the pore space within the sample in general. In this study, it is investigated that how much can the electrolyte solution substitute the pore fluid by repeating the same saturation process. Four kinds of NaCl solutions of 8, 160, 3200, 64000 ${\mu}S$/cm are used. The saturation process has repeated four times for each electrolyte in increasing conductivity order first then four times each in decreasing order. The more the saturation process repeated with the same electrolyte, the more electrolyte solution substitute the pore fluid. Geometric mean of bulk resistivity in increasing and decreasing orders with the same electrolyte solution is assumed to be mostly close to the bulk resistivity with perfect substitution. Bulk resistivity measurements for both increasing and decreasing order differs within 10% to the geometric mean when repeating the saturation process 4 times while maximum 40% difference is observed when single saturation process for each electrolyte solution with increasing order. The modified parallel resistant model can generally represent the relations between pore fluid resistivity and bulk resistivity in the experiment, but more experimental data with various rock samples with different porosity is needed to generalize the model.

Predicting Potential Distribution of Monochamus alternatus Hope responding to Climate Change in Korea (기후변화에 따른 솔수염하늘소(Monochamus alternatus) 잠재적 분포 변화 예측)

  • Kim, Jaeuk;Jung, Huicheul;Park, Yong-Ha
    • Korean journal of applied entomology
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    • v.55 no.4
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    • pp.501-511
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    • 2016
  • Predicting potential spatial distribution of Monochamus alternatus, a major insect vector of the pine wilt disease, is essential to the spread of the pine wilt disease. The purpose of this study was to predict future domestic spatial distribution of M. alternatus by using the CLIMEX model considering the temperature condition of the vector's life history. To predict current distribution of M. alternatus, the administrative divisions data where the pine wilt spots caused by M. alternatus were found from 2006 to 2014 and the 10-year mean climate observed data in 68 meteorological stations from 2006 to 2015 were used. Eight parameter sets were chosen based on growth temperature range of M. alternatus reported in preceding researches. Error matrix method was utilized to select and simulate the parameter sets showing the highest correlation with the actual distribution. Regarding the future distribution of M. alternatus, two periods of 2050s(2046-2055) and 2090s(2091-2100) were predicted using the projected climate data of RCP 8.5 Scenario generated from Korea Meteorological Administration. Overall results of M. alternatus distribution simulation were fit in the actual distribution; however, overestimation in Seoul Metropolitan area and Chungnam Region were shown. Gradual expansion of M. alternatus would be expected to nationwide from western and southern coastal areas of Korea peninsula.

Assessment of Wave Power Potential in the Kangwon and Dongnam Regions, Korea (강원권 및 동남권 지역의 파력발전 잠재성 평가)

  • Jang, Mi-Hyang;Choi, Yo-Soon
    • Journal of the Korean Association of Geographic Information Studies
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    • v.16 no.4
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    • pp.91-105
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    • 2013
  • This study performed an assessment of wave power potential in the Kangwon and Dongnam regions encompassing the East Sea and part of South Sea. Annual electricity production and economic effects of 28 wave energy converters with 750kW capacity were analyzed using significant wave height and peak wave period data(created from the NOAA's NWW3 model) and InVEST software(developed by Stanford University and University of Minnesota). Annual electricity production was estimated to be up to 1,207MWh/year and at least 163MWh/year. The spatial pattern of annual electricity production showed that the sea far from land has higher wave power potential than the sea near coast. The net present value(NPV) of 28 wave energy converters was calculated by considering an operation period of 25 years. When assuming that the electricity produced from wave energy converters is transferred to onshore power plants through underwater cables, the NPV was estimated to be up to 5,883USD(6,600,000KRW) and at least -63,494USD(-71,000,000KRW). In contrast, the NPV increased up to 28,095 USD(31,600,000KRW) when assuming that the electricity is utilized in the Ulleungdo and Dokdo. In addition, it was found that the break-even line of NPV in the East Sea becomes closer towards the land according to the increment of electricity price. The NPV of wave energy converters near the Ulleungdo and Dokdo will be 88,158 USD(99,000,000KRW) if the increment of electricity price is 100KRW.

Change Projection of Extreme Indices using RCP Climate Change Scenario (RCP 기후변화시나리오를 이용한 극한지수 변화 전망)

  • Jeung, Se-Jin;Sung, Jang Hyun;Kim, Byung-Sik
    • Journal of Korea Water Resources Association
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    • v.46 no.11
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    • pp.1089-1101
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    • 2013
  • The study uses a regional climate model to check future changes in extreme climate, to calculate extreme indexes presented by STARDEX, and to analyze the trends to predict the continuity and changes in the spatial distribution of extreme climate in the future. An analysis of extreme climate indices showed that they are likely to increase in the Seoul metropolitan area, in Gyeonggi-do, in Yongdong in Gangwon-do, and in the southern shore region of Korea. It is, however, forecasted to diminish in the central inland region. The analysis also showed that the average temperature in Korea will increase because of climate change. On the other hand, an analysis of extreme rainfall indexes showed that the trend of heavy rainfall threshold is 0.229 in Seogwipo, the greatest five-day rainfall is 5.692 in Seogwipo, and the longest dry period is 0.099 in Sokcho. Of extreme temperature indexes, the trend of Hotdays threshold is 0.777 in Incheon and the longest heat wave is 0.162 in Uljin. The Coldnight threshold is 0.075 in Inje and -0.193 in Tongyeong, according to the analysis.

Data processing system and spatial-temporal reproducibility assessment of GloSea5 model (GloSea5 모델의 자료처리 시스템 구축 및 시·공간적 재현성평가)

  • Moon, Soojin;Han, Soohee;Choi, Kwangsoon;Song, Junghyun
    • Journal of Korea Water Resources Association
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    • v.49 no.9
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    • pp.761-771
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    • 2016
  • The GloSea5 (Global Seasonal forecasting system version 5) is provided and operated by the KMA (Korea Meteorological Administration). GloSea5 provides Forecast (FCST) and Hindcast (HCST) data and its horizontal resolution is about 60km ($0.83^{\circ}{\times}0.56^{\circ}$) in the mid-latitudes. In order to use this data in watershed-scale water management, GloSea5 needs spatial-temporal downscaling. As such, statistical downscaling was used to correct for systematic biases of variables and to improve data reliability. HCST data is provided in ensemble format, and the highest statistical correlation ($R^2=0.60$, RMSE = 88.92, NSE = 0.57) of ensemble precipitation was reported for the Yongdam Dam watershed on the #6 grid. Additionally, the original GloSea5 (600.1 mm) showed the greatest difference (-26.5%) compared to observations (816.1 mm) during the summer flood season. However, downscaled GloSea5 was shown to have only a -3.1% error rate. Most of the underestimated results corresponded to precipitation levels during the flood season and the downscaled GloSea5 showed important results of restoration in precipitation levels. Per the analysis results of spatial autocorrelation using seasonal Moran's I, the spatial distribution was shown to be statistically significant. These results can improve the uncertainty of original GloSea5 and substantiate its spatial-temporal accuracy and validity. The spatial-temporal reproducibility assessment will play a very important role as basic data for watershed-scale water management.

Effect of Hydrosalpingeal Fluid on the Implantation in-vitro in a Murine Model (생쥐 배아의 체외배양 시 착상과정에 대한 난관수종액의 영향)

  • Jun, Jin-Hyun;Koong, Mi-Kyoung;Lim, Chun-Kyu;Kim, Soo-Kyung;Kang, Inn-Soo
    • Clinical and Experimental Reproductive Medicine
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    • v.27 no.2
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    • pp.159-164
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    • 2000
  • 연구목적:인간의 체외수정 및 배아이식술에서 난관수종을 갖는 환자에서 임신율과 착상률이 감소된다는 보고들이 있지만 이에 대한 명확한 기작은 밝혀지지 않았다. 본 연구에서는 생쥐 배아를 이용한 체외 착상모델에서 인간의 난관수종액(HSF)이 착상과정에 미치는 영향을 알아보고자 하였다. 연구재료 및 방법 난관수종액은 난관수종으로 수술을 받은 8명의 환자로부터 채취하였으며, 실험에 사용하기 전까지 냉동고에 보관하였다. 생쥐의 포배기 배아는 2-세포기배아를 3일 동안 배양하여 그 중 상태가 양호한 포배기 배아만을 선별하여 투명대를 제거한 후 사용하였다. 기본 배양액으로는 Ham's F-10을 사용하였으며, 배양 시 기본 배양액만을 사용한 경우를 group Ⅰ으로 하였고, 기본 배양액에 0.5% FBS를 첨가한 경우를 group Ⅱ, 0.5% FBS와 50% HSF를 첨가한 경우를 group Ⅲ , 100% HSF에 0.5% FBS를 첨가한 경우를 group Ⅳ,100% HSF만을 사용한 경우를 group Ⅴ로 하였다. 투명대를 제거한 포배기 배아를 각각의 HSF에 대한 5종류의 배양액에서 48시간 동안 배양하였다. 체외 착상 유무는 부착 부위에서 크기가 커진 영양세포들을 관찰하여 판정하였으며, 착상 부위의 표면적은 화상분석기를 이용하여 산출하였다. 결 과: 생쥐 배아의 체외 착상률은 group Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅴ에서 각각 0%, 98.9%, 77.5%, 40.4%, 10.0%로 나타났으며, 착상 부위의 평균 표면적은 group Ⅱ, Ⅲ, Ⅳ, Ⅴ에서 각각 $74,675{\pm}25,201{\mu}m^2$, $59,024{\pm}25,877{\mu}m^2$, $45,156{\pm}22,654{\mu}m^2$, $38,254{\pm}17,115{\mu}m^2$이었다. 체외 착상률과 부위의 표면적은 HSF의 농도가 증가함에 따라 통계적으로 유의하게 감소하였다(p<0.001). 결론:인간의 난관수종액(HSF)은 생쥐 배아의 체외 착상과 영양배엽세포의 증식을 억제하는 것으로 확인되었으며, 이러한 원인이 난관수종을 갖는 환자에서 임신율이 낮은 것과 밀접한 관련이 있을 것으로 생각된다.

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Comparison of Sea Level Data from Topex/Poseidon in-situ Tide-Gauges in the East Sea (한반도 동해상에서의 Topex/Poseidon 고도자료와 현장 조위계 관측 자료의 비교연구)

  • Youn, Yong-Hoon;Kim, Na-Young;Kim, Ki-Hyun;Hwang, Jong-Sun;Kim, Jeong-Woo
    • Journal of the Korean earth science society
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    • v.23 no.4
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    • pp.349-356
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    • 2002
  • In an effort to properly assess the validity of spaceborne radar altimeter measurements, we made a direct comparison of two different sea surface heights (SSH) acquired by both Topex/Poseidon (T/P) satellite and in-situ tide-gauges (T/G). This comparative analysis was conducted using the data sets collected from three locations along the eastern coast of Korea which include: Ulleungdo, Pohang, and Sokcho. In the course of the analysis of satellite altimeter, information of SSH was extracted from the T/P MGDR data sets through the application of both atmospheric and geophysical corrections. To compare the T/P data sets in parallel basis, the T/G data sets were averaged using the measured values within the peripheral radius of 55km. When compared among different locations, the compatibility between the two methods was much more significant in an offshore location (Ulleungdo) than the two onshore locations (Pohang, Sokcho). If the low-pass filtered results were compared among the sites, the offshore site exhibited the best correlations between the two methods (correlation coefficient of 0.91) than those of the onshore sites. These large differences in the strength of correlations among different locations are due to the deformation of M2, S2, and K1 tidal components used in the tidal model. In case of the offshore location, the compatibility of the two different methods were improved systematically by the low-pass filtering with an increase of the filtering duration such as up to 200 days.

Assessment of Canopy Fuel Characteristics for Five Major Coniferous Species in Korea (우리나라 주요 침엽수종의 수관층 연료특성 평가)

  • Kim, Sungyong;Jang, Mina;Lee, Byungdoo;Lee, Youngjin
    • Journal of Korean Society of Forest Science
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    • v.102 no.2
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    • pp.247-254
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    • 2013
  • The objective of this study was to assess the canopy fuel characteristics of five major coniferous species in Korea. This study was also developed allometric equations for the canopy fuel load and canopy base height of the major coniferous species using the allomeric equations of biomass developed by the Korea Forest Research Institute and the data from the $5^{th}$ National Forest Inventory. Among the major coniferous fuel types, Pinus koraiensis stands had the highest mean canopy bulk density, 0.34 kg/$m^3$, followed by Gangwon region Pinus densiflora stands 0.28 kg/$m^3$, Pinus thunbergii stands 0.24 kg/$m^3$, Pinus rigida stands 0.15 kg/$m^3$, Central region Pinus densiflora stands 0.12 kg/$m^3$ and Larix leptolepis stands 0.09 kg/$m^3$. The adjusted multiple coefficient of determination of the developed models ranged from 0.6321 to 0.9950 for canopy fuel load and 0.6390 to 0.8539 for canopy base height.