• Journal of Korean Society of Forest Science
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• v.109 no.4
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• pp.477-483
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• 2020

We constructed a stand yield table for Chamaecyparis obtusa based on data from an actual forest. The previous stand yield table had a number of disadvantages because it was based on actual forest information. In the present study we used data from more than 200 sampling plots in a stand of Chamaecyparis obtusa. The analysis included theestimation, recovery and prediction of the distribution of values for diameter at breast height (DBH), and the result is a valuable process for the preparation ofstand yield tables. The DBH distribution model uses a Weibull function, and the site index (base age: 30 years), the standard for assessing forest productivity, was derived using the Chapman-Richards formula. Several estimation formulas for the preparation of the stand yield table were considered for the fitness index, and the optimal formula was chosen. The analysis shows that the site index is in the range of 10 to 18 in the Chamaecyparis obtusa stand. The estimated stand volume of each sample plot was found to have an accuracy of 62%. According to the residuals analysis, the stands showed even distribution around zero, which indicates that the results are useful in the field. Comparing the table constructed in this study to the existing stand yield table, we found that our table yielded comparatively higher values for growth. This is probably because the existing analysis data used a small amount of research data that did not properly reflect. We hope that the stand yield table of Chamaecyparis obtusa, a representative species of southern regions, will be widely used for forest management. As these forests stabilize and growth progresses, we plan to construct an additional yield table applicable to the production of developed stands.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.578-580
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• 2019

우리 나라의 딸기 수경재배 면적은 2002년 5ha로 시작해서, 2007년에는 84ha, 2012년에는 317ha, 2017년에 1,575ha로 매년 30% 이상 급속하게 성장하고 있다. 이런 경향은 수경재배가 토양재배보다 작업이 용이하여 노동시간이 절약되며, 수량을 더 많이 생산할 수 있기 때문이다. 하지만, 공급양액을 배액으로 흘려버리는 비순환식 수경재배 방식이 증가 하면서 환경오염을 유발시킬 뿐만 아니라 수경재배 운영비용의 증가를 가져오고 있다. 본 논문은 작물 생장에 최적화된 양액공급을 위해 상관관계 분석 및 다중 선형 회귀 모델 기반의 딸기 수경재배 환경에서의 최적 양액 흡수량을 분석하고 추정해 보았다. 분석 결과, 수경재배 환경정보(일사량, 온도, 습도, CO₂ 등)를 대상으로 일사량 및 온도가 습도 및 CO₂에 비해 딸기재배를 위한 양액 흡수량에 더 큰 영향을 주는 것으로 분석되었고, 다중 선형 회귀 모델을 통한 회귀식의 R-Square값은 0.358으로 나타났다.

• The Korean Journal of Pesticide Science
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• v.6 no.4
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• pp.279-286
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• 2002

To improve the growth inhibition activities and selectivities for quinclorac family, novel 3-substituted phenyl-5-(3,7-dichloro-8-quinolinyl)-1,2,4-oxadiazole derivatives as the substrate were synthesized and their the activities ($pI_{50}$) against shoot and root of rice plant (Oryza sativa L.) and barn-yard grass (Echinochloa crus-galli) were measured. And the quantitative structure-activity relationships (QSARs) between physicochemical parameters of the substitutents (R) on phenyl group and the activities ($pI_{50}$) were analyzed quantitatively. According to the SAR analyses, the substrates of planar conformation showed higher herbicidal activities against barnyard grass than rice plant. The activities against rice plant depend on the electronic effect (shoots: ${\sigma}_{opt.}=0.49$ & root: $R_{opt.}=-0.15$) of substituents, whereas the activities against shoots and roots of barnyard grass depend on hydrophobicity (${\pi}_{opt.}=0.37{\sim}2.40$). There were conditions of selective growth inhibition activity against barnyard grass when such a ortho-substituted electron donating substituents showing the hydrophobicity value, ${\pi}=2.40$ were introduced on the phenyl ring. The 2-tolyl substituent predicted from SAR equations was expected to have better growth inhibition activity and selectivity (${\Delta}pI_{50}=1.26$) for barnyard grass.

• Korean Journal of Environmental Biology
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• v.32 no.2
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• pp.118-128
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• 2014

The growth rate of Skeletonema marinoi-dohrnii complex isolated from Gyeonggi Bay was studied in on axenic batch cultures, under non-nutrient limited condition to determine the growth rate over a wide range of light intensities ($5{\sim}500{\mu}mol\;m^{-2}s^{-1}$) and temperature ($2{\sim}35^{\circ}C$). This species exhibited its maximum specific growth rate of $2.48d^{-1}$ at a combination of $26.1^{\circ}C$ and light intensity of $197{\mu}mol\;m^{-2}s^{-1}$ as associated to optimal conditions of light and temperature. The results supported that S. marinoi-dohrnii complex are more likely to occur in late winter-spring blooms in the western and southern Korea as well as Gyeonggi Bay due to relatively high growth rates ($0.79{\sim}1.61d^{-1}$), considering the effect of temperature on nutrient competition among Skeletonema species. This study might be helpful to improve the precision and reality of a coastal ecosystem model.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.2
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• pp.78-82
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• 2022

Phenology determines the timing of crop development, and the timing of phenological events is strongly influenced by the temperature during the growing season. In process-based model, leaf area is simulated dynamically by coupling of morphology and phenology module. Therefore, the prediction of leaf appearance rate and final leaf number affects the performance of whole crop model. The dataset for the model equation was collected from SPA R chambers with five different temperature treatments. Beta distribution function (proposed by Yan and Hunt (1999)) was used for describing the leaf appearance rate as a function of temperature. The optimum temperature and the critical value were estimated to be 26.0℃ and 35.3℃, respectively. For evaluation of the model, the accumulated number of onion leaves observed in a temperature gradient chamber was compared with model estimates. The model estimate is the result of accumulating the daily increase in the number of onion leaves obtained by inputting the daily mean temperature during the growing season into the temperature model. In this study, the coefficient of determination (R²) and RMSE value of the model were 0.95 and 0.89, respectively.

• Journal of Korean Society of Forest Science
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• v.112 no.2
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• pp.195-208
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• 2023

This study aimed to use three-dimensional point cloud data (PCD) obtained from Terrestrial Laser Scanning (TLS) and Mobile Laser Scanning (MLS) to evaluate a deep learning-based species classification model for two tree species: Pinus koraiensis and Larix kaempferi. Sixteen models were constructed based on the three conditions: LiDAR platform (TLS and MLS), down-sampling intensity (1024, 2048, 4096, 8192), and deep learning model (PointNet, PointNet++). According to the classification accuracy evaluation, the highest kappa coefficients were 93.7% for TLS and 96.9% for MLS when applied to PCD data from the PointNet++ model, with down-sampling intensities of 8192 and 2048, respectively. Furthermore, PointNet++ was consistently more accurate than PointNet in all scenarios sharing the same platform and down-sampling intensity. Misclassification occurred among individuals of different species with structurally similar characteristics, among individual trees that exhibited eccentric growth due to their location on slopes or around trails, and among some individual trees in which the crown was vertically divided during tree segmentation.

• Journal of Bio-Environment Control
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• v.31 no.3
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• pp.246-254
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• 2022

Domestic facility agriculture grows rapidly, such as modernization and large-scale. And the production scale increases significantly compared to the area, accounting for about 60% of the total agricultural production. Greenhouses require energy input to create an appropriate environment for stable mass production throughout the year, but the energy load per unit area is large because of low insulation properties. Through the rooftop greenhouse, one of the types of urban agriculture, energy that is not discarded or utilized in the building can be used in the rooftop greenhouse. And the cooling and heating load of the building can be reduced through optimal greenhouse operation. Dynamic energy analysis for various environmental conditions should be preceded for efficient operation of rooftop greenhouses, and about 40% of the solar energy introduced in the greenhouse is energy exchange for crops, so it should be considered essential. A major analysis is needed for each sensible heat and latent heat load by leaf surface temperature and evapotranspiration, dominant in energy flow. Therefore, an experiment was conducted in a rooftop greenhouse located at the Korea Institute of Machinery and Materials to analyze the energy exchange according to the growth stage of crops. A micro-meteorological and nutrient solution environment and growth survey were conducted around the crops. Finally, a regression model of leaf temperature and evapotranspiration according to the growth stage of leafy vegetables was developed, and using this, the dynamic energy model of the rooftop greenhouse considering heat transfer between crops and the surrounding air can be analyzed.

• Journal of Korea Foresty Energy
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• v.24 no.2
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• pp.37-45
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• 2005

This study presents a method how to estimate the change of stand volume, the stand biomass and the carbon removals, using dynamic stand growth model according to whether the practices for forest management are implemented or not. As a result, it shows that the rate of stand change was significantly high if the practices were implemented. Consequently, the change of carbon removals was also high. The carbon removals at the stand where the practices were not implemented, was estimated about 0.27tC/ha. And the carbon removals at the stand where the practices were implemented, was estimated 166.02tC/ha(thinning from above) and 163.75tC/ha(thinning from below). It is confirmed that the thinning activities has a great influence on the change of carbon removals and there was little difference of the carbon removals between thinning types. From this result, it is proved that forest management like thinning activities is prerequisite condition to improve the carbon removals of stand.

• Journal of Climate Change Research
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• v.4 no.2
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• pp.177-188
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• 2013

In this research, forest cover distribution change, forest volume and carbon stock in Yongin-city, Gyeonggi procince were estimated focused on the forest of Yongin-City using forest type map and HyTAG model in relation to climate change. Present forest volume of Yongin-city was estimated using the data from $5^{th}$ Forest Type Map and Korean National Forest Inventory (NFI). And for the future 100 years potential forest distribution by 10-year interval were estimated using HyTAG model. Forest volume was also calculated using algebraic differences form of the growth model. According to the $5^{th}$ Forest Type Map, present needleleaf forest occupied 37.8% and broadleaf forest 62.2% of forest area. And the forest cover distribution after 30 years would be changed to 0.13% of needleleaf forest and 99.97% of broadleaf forest. Finally, 60 years later, whole forest of Yongin-city would be covered by broad-leaf forest. Also the current forest carbon stocks was measured 1,773,862 tC(56.79 tC/ha) and future carbon stocks after 50 years was predicted to 4,432,351 tC(141.90 tC/ha) by HyTAG model. The carbon stocks after 100 years later was 6,884,063 tC (220.40 tC/ha). According to the HyTAG model prediction, Pinus koraiensis, Larix kaempferi, Pinus rigida, and Pinus densiflora are not suitable to the future climate of 10-year, 30-year, 30-year, and 50-year later respectively. All Quercus spp. was predicted to be suitable to the future climate.

• Horticultural Science & Technology
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• v.33 no.6
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• pp.911-922
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• 2015

This study was carried out to evaluate growth characteristics of Kimchi cabbage cultivated in various highland areas, and to create a predicting model for the production of highland Kimchi cabbage based on the growth parameters and climatic elements. Regression model for the estimation of head weight was designed with non-destructive measured growth variables (NDGV) such as leaf length (LL), leaf width (LW), head height (HH), head width (HW), and growing degree days (GDD), which was $y=6897.5-3.57{\times}GDD-136{\times}LW+116{\times}PH+155{\times}HH-423{\times}HW+0.28{\times}HH{\times}HW{\times}HW$, ($r^2=0.989$), and was improved by using compensation terms such as the ratio (LW estimated with GDD/measured LW ), leaf growth rate by soil moisture, and relative growth rate of leaf during drought period. In addition, we proposed Excel spreadsheet model for simulation of yield prediction of highland Kimchi cabbage. This Excel spreadsheet was composed four different sheets; growth data sheet measured at famer's field, daily average temperature data sheet for calculating GDD, soil moisture content data sheet for evaluating the soil water effect on leaf growth, and equation sheet for simulating the estimation of production. This Excel spreadsheet model can be practically used for predicting the production of highland Kimchi cabbage, which was calculated by (acreage of cultivation) ${\times}$ (number of plants) ${\times}$ (head weight estimated with growth variables and GDD) ${\times}$ (compensation terms derived relationship of GDD and growth by soil moisture) ${\times}$ (marketable head rate).