• Title/Summary/Keyword: coefficients of determination

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Estimation of forest Site Productivity by Regional Environment and Forest Soil Factors (권역별 입지$\cdot$토양 환경 요인에 의한 임지생산력 추정)

  • Won Hyong-kyu;Jeong Jin-Hyun;Koo Kyo-Sang;Song Myung Hee;Shin Man Yong
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.7 no.2
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    • pp.132-140
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    • 2005
  • This study was conducted to develop regional site index equations for main tree species in Gangwon, Gyunggi-Chungcheong, Gyungsang, and Jeolla area of Korea, using environmental and soil factors obtained from a digital forest site map. Using the large data set obtained from the digital forest map, a total of 28 environmental and soil factors were regressed on site index by tree species for developing the best site index equations for each of the regions. The selected main tree species were Larix 1eptolepis, Pinus koraiensis, Pinus densiflora, Pinus thunbergii, and Quercus acutissima. Finally, four to five environmental and soil factors by species were chosen as independent variables in defining the best regional site index equations with the highest coefficients of determination $(R^2)$. For those site index equations, three evaluation statistics such as mean difference, standard deviation of difference and standard error of difference were applied to the data sets independently collected from fields within the region. According to the evaluation statistics, it was found that the regional site index equations by species developed in this study conformed well to the independent data set, having relatively low bias and variation. It was concluded that the regional site index equations by species had sufficient capability for the estimation of site productivity.

The Effect of Resilience in Career Decision-Making among Specialized Technical High School Students (특성화고등학교 학생의 회복탄력성이 진로결정 자기효능감에 미치는 영향)

  • Park, Najeong;Lim, Nhayoung;Lee, Chang-Hoon
    • 대한공업교육학회지
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    • v.43 no.1
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    • pp.20-40
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    • 2018
  • This study examined resilience and career decision-making among specialized technical high school students with the aim of proposing preliminary data to suggest ways to improve self-efficacy in career decision-making through establishing proper resilience. The specific research questions were set as; first, to define the resilience status in relation to the students' personal characteristics among students; second, to describe the status of self-efficacy in career decision-making related to the students' personal characteristics among students; and last, to examine the influence of resilience on self-efficacy in career decision-making among specialized technical high school students. To accomplish such research objectives, the assessment survey was developed after reviewing the theoretical literature on specialized technical high school students' background, ego identity, and self-efficacy in career decision-making. The survey was comprised of 54 items including personal characteristics (3 items), resilience (27 items), and self-efficacy in career decision-making (24 items). A total of 990 students from industrial specialized high schools across the country completed the survey, and the responses from 775 students were used for the final analyses after excluding the surveys with unanswered items or untrustworthy responses. Results were as follows: The group with higher levels of school adaptation and satisfaction showed higher resilience and career decision-making than those with lower levels of school adaptation and satisfaction. Furthermore, for the influence of resilience on self-efficacy in career decision-making, the results showed that resilience had positive associations with self-efficacy in career decision-making, and all correlations and coefficients of determination showed a robust statistical significance. Therefore, to enhance self-efficacy in career decision-making, education that could help students better adapt to school, increase satisfaction with the school, and create positive resilience must precede.

Optimization of Extraction Conditions for Ethanol Extracts from Chrysanthemum morifolium by Response Surface Methodology (반응표면분석에 의한 소국(小菊) 에탄올 추출물의 추출조건 최적화)

  • Park, Nan-Young;Kwon, Joong-Ho;Kim, Hyun-Ku
    • Korean Journal of Food Science and Technology
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    • v.30 no.5
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    • pp.1189-1196
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    • 1998
  • Extraction conditions were optimized using response surface methodology for preparing high-quality ethanol extracts from cultivated Chrysanthemum petals. A fractional factorial design was applied to investigate effects of solvent ratio to sample $(X_1)$, ethanol concentration $(X_2)$ and extraction time $(X_3)$ at $60^{\circ}C$ on dependent variables of the extract properties, such as yellow color $(Y_1)$, carotenoids $(Y_2)$, soluble solids $(Y_3)$, phenolic compounds $(Y_4)$, electron donating ability $(Y_5)$, sensory color $(Y_6)$ and sensory aroma $(Y_7)$. Second-order models were employed to generate 3-dimensional response surfaces for dependent variables and their coefficients of determination $(R^2)$ were ranged from 0.8063 to 0.9963. Optimum extraction conditions for each variable were 115 mL/g, 97%, 18 hr in yellow color, 145 mL/g, 50%, 12 hr in carotenoids, 147 mL/g, 48%, 17 hr in soluble solids, 116 mL/g, 68%, 17 hr in phenolic compounds, 110 mL/g, 98%, 14 hr in electron donating ability, 101 mL/g, 48%, 54 hr in organoleptic color and 109 mL/g, 54%, 4 hr in organoleptic aroma, respectively. The range of optimum conditions at 16hr extraction for maximized characteristics of ethanol extracts was $103{\sim}122\;mL/g$ and $64{\sim}78%$. Predicted values at the optimum condition agreed with experimental values.

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Evaluation of near-realtime weekly root-zone Soil Moisture Index (SMI) for the extreme climate monitoring web-service across East Asia (동아시아 이상기후 감시 서비스를 위한 지면모형 기반 준실시간 토양수분지수평가)

  • Chun, Jong Ahn;Lee, Eunjeong;Kim, Daeha;Kim, Seon Tae;Lee, Woo-Seop
    • Journal of Korea Water Resources Association
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    • v.53 no.6
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    • pp.409-416
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    • 2020
  • An extreme climate monitoring is essential to the reduction of socioeconomic damages from extreme events. The objective of this study was to produce the near-realtime weekly root-zone Soil Moisture Index (SMI) on the basis of soil moisture using the Noah 3.3 Land Surface Model (LSM) for potentially monitoring extreme drought events. The Yangtze basin was selected to evaluate the Noah LSM performance for the East Asia region (15-60°N, 70-150°E) and the evapotranspiration (ET) and sensible heat flux (SH) were compared with ET and SH from FluxNet and with ET from FluxCom, Global Land Evaporation Amsterdam Model (GLEAM), ERA-5, and Generalized Complementary Relationship (GCR). For the ET, the coefficients of determination (R2) were higher than 0.96, while the R2 value for the SH was 0.71 with slightly lower than those. A time series of the weekly root-zone SMI revealed that the regions with Extreme drought had been expanded from the northern part of East China to the entire East China between July to October 2019. The trend analysis of the number of extreme drought events showed that extreme drought events in spring had reduced in South Korea over the past 20 years, while those in fall had a tendency to increase. It is concluded that this study can be useful to reduce the socioeconomic damages resulted from climate extremes by comprehensively characterizing extreme drought events.

Studies on Measuring Volatile Terpenoids in Carrots Using the Direct Headspace Sampling Method (Direct Headspace Sampling 방법을 이용한 당근의 휘발성 Terpenoids 분석에 관한 연구)

  • Park, Yong;Ryu, Jang-Bal;Park, Sang-Gyu;Park, Shin
    • Applied Biological Chemistry
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    • v.40 no.6
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    • pp.536-540
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    • 1997
  • Volatile terpenoids of carrots were measured by the direct headspace sampling method(DHS) with gas chromatography as a study for the breeding of high quality carrots. Using this method, 7 terpenoids such as ${\alpha}-pinene$, ${\beta}-pinene$, ${\beta}-myrcene$, ${\alpha}-terpinene$, limonene, ${\gamma}-terpinene$, and terpinolene were clearly separated. However ${\alpha}-phellandrene$ was not clearly separated from ${\beta}-myrcene$. In addition to this, higher boiling point compounds such as terpinen-4-ol, bornyl acetate, and ${\alpha}-bisbolol$ were not found. The coefficients of $determination(r^2)$ for the 7 terpenoids were higher than 0.99 and the standard curves were highly significant. Four replicated samples using this method demonstrated great reproducibility; the coefficidnt of variation (C.V.) for ${\alpha}-pinene$, ${\beta}-pinene$, ${\beta}-myrcene$, limonene, ${\gamma}-terpinene$, terpinolene, and total terpenoids were 6.8, 6.8, 8.4, 7.1, 3.8, 10.1, 7.1%. Sixty five carrot cultivars breeded worldwide were evaluated for the 7 terpenoids and total terpenoids; the range for ${\alpha}-pinene$, ${\beta}-pinene$, ${\beta}-myrcene$, ${\alpha}-terpinene$, limonene, ${\gamma}-terpinene$, terpinolene, and total terpenoids were $0.28{\sim}2.48\;ppm$, $0.35{\sim}1.87\;ppm$, $0.56{\sim}1.51\;ppm$, 0 ppm, $0.59{\sim}1.84\;ppm$, $0.87{\sim}3.33\;ppm$, $5.15{\sim}35.81\;ppm$, and $9.07{\sim}42.30\;ppm$, respectively. Big differences in each terpenoid and total terpenoids were found among cultivars. On the total terpenoids of the 65 cultivars, 5 cultivars(7.7%) contained less than 10 ppm, 15 cultivars (23.1%) $10{\sim}11.99\;ppm$, 14 cultivars(21.5%) $12{\sim}13.99\;ppm$, 9 cultivars(13.8%) $14{\sim}15.99\;ppm$, 10 cultivars(15.4%) $16{\sim}17.99\;ppm$, 4 cultivars(6.2%) $18{\sim}19.99\;ppm$, 5 cultivars(7.7%) $20{\sim}29.99\;ppm$, and 3 cultivars(4.6%) were higher than 30 ppm. Generally, cultivars developed in Japan contained less total terpenoids than cultivars developed in Europe and America.

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