• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.3
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• pp.164-178
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• 2022

Uncertainties in weather forecasts would affect the reliability of yield prediction using crop models. The objective of this study was to compare uncertainty in crop yield prediction caused by the use of the weather forecast data. Daily weather data were produced at 10 km spatial resolution using W eather Research and Forecasting (W RF) model. The nearest neighbor method was used to downscale these data at the resolution of 5 km (W RF5K). Parameter-elevation Regressions on Independent Slopes Model (PRISM) was also applied to the WRF data to produce the weather data at the same resolution. W RF5K and PRISM data were used as inputs to the CROPGRO-SOYBEAN model to predict crop yield. The uncertainties of the gridded data were analyzed using cumulative growing degree days (CGDD) and cumulative solar radiation (CSRAD) during the soybean growing seasons for the crop of interest. The degree of agreement (DOA) statistics including structural similarity index were determined for the crop model outputs. Our results indicated that the DOA statistics for CGDD were correlated with that for the maturity dates predicted using WRF5K and PRISM data. Yield forecasts had small values of the DOA statistics when large spatial disagreement occured between maturity dates predicted using WRF5K and PRISM. These results suggest that the spatial uncertainties in temperature data would affect the reliability of the phenology and, as a result, yield predictions at a greater degree than those in solar radiation data. This merits further studies to assess the uncertainties of crop yield forecasts using a wide range of crop calendars.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.50
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• pp.105-125
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• 1999

The results of analysis on foreign exchange market, stock and financial market after January of 1997 are that foreign exchange market will be affected by stock and financial market volatility about 1999. This means that stock and financial market are more stable than foreign exchange market. This also is supported by ‘financial market forecast of 1999 in Daewoo Economic Research Institute’. After won/dollar (end of period) will be increasing in 1,430 at second quarter of 1999, this is to downward 1,200 fourth quarter of 1999. This is somewhat based on government's higher exchange rate policy. But, after yield of corporate bond is to 11.0% at first quarter of 1999, this will be stable to 10.2% at fourth quarter. During the first quarter of 1999, yield of corporate bond is to somewhat increasing through sovereign debt and public bonds, technical adjustment of interest rate. After this, yield of corporate bond will be stable according to stability of price, magnification of money supply, restucturing of firms. So, stock market is favorably affected by stability of financial market. But, the pension and fund of USA, i.e., long-term portfolio investment fund, are injected through international firm's management. It is included by openness of audit, fair market about foreign investors. Finally, Moody's strong rating on the won-denominated bonds suggest that Korea's sovereign debt ratings could be restored to an investment grade in the near future. It sequentially includes inflow of foreign portfolio investment fund, fall of won/dollar foreign exchange rate (appreciation of won) and stability of yield of corporate bond.

• Korean Journal of Plant Resources
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• v.14 no.3
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• pp.229-234
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• 2001

In order to investigate the possibility of utilizing small cermet as a seed corm in taro, the small cermets classified by the weight were planted on April 30,2000. The effect of weight of small cermets(5,10, If,20,25, and 30g) and corms on the growth, yield, and quality of taro was compared to those raised from cermets. The larger the size of cormel was, the more number of leaves developed, and the higher the yield was. Also the growth of small cormel was normal, so we forecast that it is possible to use small cermet as seed corm in mass production of taro.

• Korean Journal of Agricultural and Forest Meteorology
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• v.1 no.1
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• pp.12-19
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• 1999

CERES-rice, a rice growth simulation model, was used in conjunction with daily weather data to figure out the spatial variation of the phenology and yields of paddy rice at 168 rice cultivation zone units(CZU) of Kyunggi Province in 1997. Two sets of cultivar specific coefficients, which represent early and mid-season maturing varieties, were derived from field experiments conducted at two crop experiment stations. The minimum data set to run the model for each CZU (daily maximum and minimum temperature, solar irradiance, and rainfall) was obtained by spatial averaging of existing 'Digital Map of Korean Climate'(Shin et al., 1999). Soil characteristics and management information at each CZU were available from the Rural Development Administration. According to a preliminary test using 5 to 9 years field data, trends of the phasic development(heading and physiological maturity), which were obtained from the model adjusted for these coefficients, were in good agreement with the observed data. However, the simulated inter-annual variation was somewhat greater than the reported variation. Rough rice yields of the early maturing cultivar calculated by the model were comparable with the reported data in terms of both absolute value and inter -annual variation. But those of the mid season cultivar showed overestimation. After running the simulation model runs with 1997 weather data for 168 CZU's, rough rice yields of the 168 CZU's calculated by the model were aggregated into corresponding 33 counties by acreage-weighting to facilitate direct comparison with the reported statistics from the Ministry of Agriculture and Forestry. The simulation results were good at 22 out of the 26 counties with reportedly increasing yield trend with respect to the past 9 years average.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.4
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• pp.462-470
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• 2012

The availability and efficient use of the feed resources in India are the primary drivers to maximize productivity of Indian livestock. Feed security is vital to the livestock management, extent of use, conservation and productivity enhancement. Assessment and forecasting of livestock feed resources are most important for effective planning and policy making. In the present study, 40 years of data on crop production, land use pattern, rainfall, its deviation from normal, area under crop and yield of crop were collected and modeled to forecast the likely production of feed resources for the next 20 years. The higher order auto-regressive (AR) models were used to develop efficient forecasting models. Use of climatic variables (actual rainfall and its deviation from normal) in combination with non-climatic factors like area under each crop, yield of crop, lag period etc., increased the efficiency of forecasting models. From the best fitting models, the current total dry matter (DM) availability in India was estimated to be 510.6 million tonnes (mt) comprising of 47.2 mt from concentrates, 319.6 mt from crop residues and 143.8 mt from greens. The availability of DM from dry fodder, green fodder and concentrates is forecasted at 409.4, 135.6 and 61.2 mt, respectively, for 2030.

• Korean Journal of Remote Sensing
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• v.29 no.5
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• pp.461-476
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• 2013

Carnegie-Ames-Stanford Approach (CASA) model is one of the most quick, convenient and accurate models to estimate the NPP (Net Primary Productivity) of vegetation. The purposes of this study are (1) to examine the spatial and temporal patterns of vegetation NPP of the paddy field area in Korea from 2002 to 2012, and (2) to investigate how the rice productivity responded to inter-annual NPP variability, and (3) to estimate rice yield in Korea using CASA model applied to MOderate Resolution Imaging Spectroradiometer (MODIS) products and solar radiation. MODIS products; MYD09 for NIR and SWIR bands, MYD11 for LST, MYD15 for FPAR, respectively from a NASA web site were used. Finally, (4) its applicability is to be reviewed. For those purposes, correlation coefficients (linear regression for monthly NPP and accumulated NPP with rice yield) were examined to evaluate the spatial and temporal patterns of the relations. As a result, the total accumulated NPP and Sep. NPP tend to have high correlation with rice yield. The rice yield in 2012 was estimated to be 526.93kg/10a by accumulated NPP and 520.32 kg/10a by Sep. NPP. RMSE were 9.46kg/10a and 12.93kg/10a, respectively, compared with the yield forecast of the National Statistical Office. This leads to the conclusion that NPP changes in the paddy field were well reflected rice yield in this study.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.5 no.1
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• pp.51-63
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• 1997

Generally, air freight forecasting model used to major factor GNP(GDP), Yield, Exchange rate, as its independent variables. We studied about the factors that affect to Air Freight in Korea, and we found six affective variables. Those are GNP, Exchange rate, Flight routes, Flight numbers, Sum of dollars Export and import. To find the relationship between the Air Freight and GNP, Exchange rate, Flight routes, Flight numbers, Sum of dollars Export and import we used regression analysis. Through the regression analysis, we found some problems in the model. There are collieneraities between the variables, so we took the variables selection model to choose the best affective variables of air cargo. We have defined the the Korean air freight forecasting model with two variables and forecast far the $1996{\sim}2010$ period were made by using this model.

• Proceedings of the Safety Management and Science Conference
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• 2006.04a
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• pp.471-484
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• 2006

The focus of analysis is effect on Non-electrical Machinery and Equipment of Macroeconomic variables through long-term and short-term periods. Also, this paper is related with implication on steady growth possibility of Non-electrical Machinery and Equipment. The period of variables is from 1985 to April in 2005. In case of not-available data is treated as missing figures. As spatial scope, these data are Non-electrical Machinery and Equipment on the basis of KSIC. In case of items, it composes MTI 1&3 digit of Korea International Trade Association (KITA), on the basis of HSK & classification of Korea Machinery industries. According to Granger causality test, yield of Cooperate Bond and export amount of Machinery have a meaning at statistical Confidence level of 10%. In case of index of the unit cost of export and export amount of Machinery, they have an interactive Granger cause. In yen dollar exchange rate and export amount of Machinery, former variable gives an unilateral Granger cause to latter that.

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.2
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• pp.107-113
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• 2003

Analysis of combining ability is a widely used biometrical tool to select promising parents and hybrids, to determine the kinds and relative magnitudes of genetic variability among hybrids as well as to forecast yield attributes in early breeding generations both in plants and animals. Various statistical approaches like Jinks and Hayman (1953), Griffing (1956), Kempthorne (1957) etc. have been extensively applied in plants. These approaches have also been tried in the mulberry silkworm, Bombyx mori L. In the present review, an attempt has been made to collect most of the studies carried out on combining ability in silkworm at one place and make it available to the scientists engaged in sericultural research.

• Wind and Structures
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• v.6 no.3
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• pp.221-248
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• 2003

The design of high-rise building is often influenced by wind-induced motions such as accelerations and lateral deflections. Consequently, the building's structural stiffness and dynamic (vibration periods and damping) properties become important parameters in the determination of such motions. The approximate methods and empirical expressions used to quantify these parameters at the design phase tend to yield values significantly different from each other. In view of this, there is a need to examine how actual buildings in the field respond to dynamic wind loading in order to ascertain a more realistic model for the dynamic behavior of buildings. This paper describes the findings from full-scale measurements of the wind-induced response of typical high-rise buildings in Singapore, and recommends an empirical forecast model for periods of vibration of typical buildings in Singapore, an appropriate computer model for determining the periods of vibration, and appropriate expressions which relate the wind speed to accelerations in buildings based on wind tunnel force balance model test and field results.