• Transactions of the Korean Society of Automotive Engineers
• /
• v.18 no.2
• /
• pp.56-60
• /
• 2010

Since the forming process involves the strain rate effect, a yield function considering the strain rate is indispensible to predict the accurate final blank shape in the forming simulation. One of the most widely used in the forming analysis is the Hill48 quadratic yield function due to its simplicity and low computing cost. In this paper, static and dynamic uni-axial tensile tests according to the loading direction have been carried out in order to measure the yield stress and the r-value. Based on the measured results, the Hill48 yield loci have been constructed, and their performance to describe the plastic anisotropy has been quantitatively evaluated. The Hill48 quadratic yield function has been modified using convex combination in order to achieve accurate approximation of anisotropy at the rolling and transverse direction.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.51 no.6
• /
• pp.519-522
• /
• 2006

Randomized field experiments were conducted to study the interactive effect of sulphur (S) and nitrogen (N) on seed, oil and protein yield of two cultivars of groundnut {Arachis hypogea: cv Amber $(V_{1})$: cv Kaushal, $(V_{2})$.} Two dosage levels of sulphur ($0\;and\;20kg\;ha^{-1}$) and two dosage levels of N ($23.5\;and\;43.5kg\;ha^{-1}$) in various combinations were tested as micronutrient treatments, $T_{1},\;T_{2},\;and\;T_{3}$. Results indicated significant enhancement of the yield components namely seed and oil yield as well as seed protein. Maximum response was observed with treatment $T_{3}$(having 20kg S and 43.5kg N $ha^{-1})$. Increase in seed and oil yields of 90% and 103% in $V_{1}$, and 79 and 90% in $V_{2}$, respectively were recorded as compared to the control treatment $T_{1}$(having 0kg S and 23.5kg N $ha^{-1}$). Effect of S and N interaction was observed on protein, N and S content in seeds. The results obtained by these experiments clearly suggest that judicious balanced application of N and S could improve the yield.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.51 no.4
• /
• pp.269-273
• /
• 2006

Multiple linear regression analysis was conducted to interpretate the relationship between sesame grain yield and its components under early sowing cropping condition. The t test showed that stem length, number of capsules per plant, 1000 seeds weight and seed weight per plant gave significant contribution to sesame grain yield, therefore those variables were assumed to mostly influenced components to grain yield of sesame. In the stepwise regression analysis, the predicted equation for sesame grain yield per square meter (Y) was Y = -7.900 + 0.150X1 + 0.461X5 + 15.553X6 + 8.543X7. Meanwhile, F value showed that stem length, number of capsules per plant and seed weight per plant gave significant contribution to sesame grain yield, while 1000 seeds weight did not significantly show. Based on the results, it is reasonable to assume that high yield. potential of sesame under early sowing cropping condition would be obtained by selecting breeding lines with long stem length, number of capsules per plant, and seed weight per plant, which was different result at the late sowing cropping condition in which days to flowering and maturity were assumed to be more affected factors to the sesame grain yield.

• Journal of Fisheries and Marine Sciences Education
• /
• v.16 no.1
• /
• pp.84-98
• /
• 2004

Due to a publicly owned resources, the overexploitation of the fisheries resources can result in externalities in the form of reduced future levels of yield. These problems can be theoretically improved through effective management of the fishery. The paper illustrates maximum sustainable yield(MSY), maximum economic yield(MEY) and F0.1 level of fishing mortality as the concept of optimal yield, and it theoretically shows that MSY is more appropriate for the optimal yield than MEY where prices increase even though MEY achieves the maximization of economic rent in a fishery assuming constant prices. And the paper presents several fisheries management tools and policies such as input controls, output controls and taxes. As the traditional approach to fishery management, input controls involve restrictions on the physical inputs into the production process(e.g. capital, time or technology) and output controls involve limits on the quantity of fish that can be landed. To introduce user cost into the harvest decisions of rent-seeking fishers, taxation, as a bioeconomic management policy of the fisheries, directly addresses the problems associated with the resource being unpriced. As most fisheries management plans, however, have increasing fisher income as an objective, taxes have not been introduced into any fisheries management policies despite their theoretical attraction.

• Journal of Environmental Science International
• /
• v.25 no.10
• /
• pp.1433-1444
• /
• 2016

South Korea is a maritime nation, surrounded by water on three sides; hence, it is important to preserve in a sustainable manner. Most areas, especially those bordering the East Sea, have been suffering from severe coastal erosion. Information on the sediment yield of a river basin is an important requirement for water resources development and management. In Korea, data on suspended sediment yield are limited owing to a lack of logistic support for systematic sediment sampling activities. This paper presents an integrated approach to estimate the sediment yield for ungauged coastal basins by using a soil erosion model and a sediment delivery rate model in a geographic information system (GIS)-based platform. For applying the sediment yield model, a basin specific parameter was validated on the basis of field data, that, ranging from 0.6 to 1.2 for the 19 gauging stations. The calculated specific sediment yield ranged from 17 to $181t/km^2.yr$ in the various basin sizes of Korea. We obtained reasonable sediment yield values when comparing the measured data trends around the world with those in Korean basins.

• Computers and Concrete
• /
• v.6 no.4
• /
• pp.343-356
• /
• 2009

Experiments were designed to investigate the flow behavior of portland cement paste and concrete incorporating superplasticizers. The paste and concrete mixtures were subjected to prolonged mixing for up to 110 min at high temperature. The yield stress values of concrete and that of the corresponding cement paste were measured using a rotating rheometer and viscometer, respectively. The results reveal a weak linear correlation between the yield stress of concrete mixtures and that of the corresponding cement pastes. Results also indicate that the yield stress of concrete varies in a linear fashion with the elapsed time, while its variations with the temperature and superplasticizer dosage follow power and inverse power functions, respectively. In this study, the genetic algorithms (GA) technique was used to predict the yield stress of concrete considering various parameters, such as the mixing time, ambient temperature, and superplasticizer dosage. A sensitivity study was conducted to evaluate the ability of the GA equations thus developed to capture the effects of test parameters on the yield stress of concrete. It was found that the GA equations were sensitive to the effects of test parameters and provided yield stress predictions that compared well with corresponding experimental data.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.54 no.3
• /
• pp.141-148
• /
• 2012

Food policy is considered as the most basic and central issue for all countries, while making efforts to keep each country's food sovereignty and enhance food self-sufficiency. In the case of Korea where the staple food is rice, the rice yield prediction is regarded as a very important task to cope with unstable food supply at a national level. In this study, Korean paddy Rice yield Prediction Model (KRPM) developed to predict the paddy rice yield using meteorological element and MODIS NDVI. A multiple linear regression analysis was carried out by using the NDVI extracted from satellite image. Six meteorological elements include average temperature; maximum temperature; minimum temperature; rainfall; accumulated rainfall and duration of sunshine. Concerning the evaluation for the applicability of the KRPM, the accuracy assessment was carried out through correlation analysis between predicted and provided data by the National Statistical Office of paddy rice yield in 2011. The 2011 predicted yield of paddy rice by KRPM was 505 kg/10a at whole country level and 487 kg/10a by agroclimatic zones using stepwise regression while the predicted value by KOrea Statistical Information Service was 532 kg/10a. The characteristics of changes in paddy rice yield according to NDVI and other meteorological elements were well reflected by the KRPM.

• Journal of the Semiconductor & Display Technology
• /
• v.21 no.4
• /
• pp.168-173
• /
• 2022

As the function of a product is advanced and the process is refined, the yield in the fine manufacturing process becomes an important variable that determines the cost and quality of the product. Since a fine manufacturing process generally produces a product through many steps, it is difficult to find which process or equipment has a defect, and thus it is practically difficult to ensure a high yield. This paper presents the system architecture of how to build a smart manufacturing system to analyze the big data of the manufacturing plant, and the equipment factor analysis methodology to increase the yield of products in the smart manufacturing system. In order to improve the yield of the product, it is necessary to analyze the defect factor that causes the low yield among the numerous factors of the equipment, and find and manage the equipment factor that affects the defect factor. This study analyzed the key factors of abnormal equipment that affect the yield of products in the manufacturing process using the data mining technique. Eventually, a methodology for finding key factors of abnormal equipment that directly affect the yield of products in smart manufacturing systems is presented. The methodology presented in this study was applied to the actual manufacturing plant to confirm the effect of key factors of important facilities on yield.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.16 no.5
• /
• pp.1414-1430
• /
• 2022

Due to the Internet of Things popularity, many agricultural data are collected by sensors automatically. The abundance of agricultural data makes precise prediction of rice yield possible. Because the climate factors have an essential effect on the rice yield, we considered the climate factors in the prediction model. Accordingly, this paper proposes a machine learning model for rice yield prediction in Taiwan, including the genetic algorithm and support vector regression model. The dataset of this study includes the meteorological data from the Central Weather Bureau and rice yield of Taiwan from 2003 to 2019. The experimental results show the performance of the proposed model is nearly 30% better than MARS, RF, ANN, and SVR models. The most important climate factors affecting the rice yield are the total sunshine hours, the number of rainfall days, and the temperature.The proposed model also offers three advantages: (a) the proposed model can be used in different geographical regions with high prediction accuracies; (b) the proposed model has a high explanatory ability because it could select the important climate factors which affect rice yield; (c) the proposed model is more suitable for predicting rice yield because it provides higher reliability and stability for predicting. The proposed model can assist the government in making sustainable agricultural policies.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.7 no.1
• /
• pp.1-29
• /
• 1969

Experiments on rice concerning it s varieties, fertilization, seedling dates and herbicides have been conducted to determine the most desirable method of direct sowing cultivation on dry paddy field land in the middle part of Korea. The results obtained at the Office of Rural Development of Choongnam Province are as follows:. 1. Sixteen different derivatives from the main varieties of low land rice were cultivated on a dry paddy field by the direct sowing method; at the same time, a few varieties were tried adopting the common transplanting cultivation method. The yield and yield factors from these two groups were examined to give the following results: a) Compared to the common transplanting cultivation, the direct sowing method showed remarkably increased number of panicles while the number of flowers per panicle was shown to be significantly decreased. The maturing ratio was detected to be lowered. The yield horn them differed according to the different varieties : good yield was obtained from Hokwang while Norin ＃25 proved poor when compared with the common transplanting cultivation method. b) Among sixteen varieties tested, Sunsou, Norin ＃25, Jaigou, Hokwang, Palkueng and Gosi showed comparatively high yields, their yield being more than 325 kilograms per 10 Are, but Nampoong, Paldal, Nongkwang, Norin ＃29, Eunbangju ＃101 and Shiro gane showed less yield, their yield being less than 271 kilograms per 10 Are, the relations between the yield and the yield factors can be summarized as follows; Number of varieties and their rice yield. 1) The varieties which were great in the, number of panicles and high in yield=Jaigoun, Hokwang Palkueng and Gosi. 2) The varieties which were low in the number of panicles and high in yield=Sounsou and Norin ＃25. 3) The varieties which were great in the number of panicles and poor in yield=Eunbangju ＃101 and Sirogane. 4) The varieties which were poor in the number of panicles and poor in yield: Nampung, Paldal and Norin ＃29. Number of flowers per panicle and yield. 1) The varieties which were great in the number of flowers per panicle and high in yield: Sounsou, Norin ＃25 and Gosi. 2) The varieties which were poor in the number of flowers per panicle and high in yield ; Jaigoun, Hokwang and Palkueng. 3) The varieties which were great in the number of flowers per panicle and poor in yield: Paldal and Nampung. 4) The varieties which were poor in the number of flowers per panicle and poor in yield: Norin ＃29. Eunbangju ＃101 and Sirogane. Maturing ratio and yield. 1) The varieties which were high in the maturing ratio and high in yield: Jaigoun, Sounsou, Norin ＃25 and Palkueng. 2) The varieties which were low in the maturing ratio and high in yield: Hokwang and Gosi. 3) The varieties which were early maturing rat io and low in yield: Hokwang and Gosi. 4) The varieties which were late maturing ratio and poor in yield: Eunbangju ＃101, Nampungand Sirogane 1, 000 grain weight and yield. 1) The varieties which were heavy in 1, 000 grains weight and high in yield=Norin ＃25 and Hokwang. 2) The varieties which were light in 1, 000 grains weight and high in yield=Sounsou and Jaigoun. 3) The varieties which were heavy in 1, 000 grains weight and poor in yield=Nongkwang and Eunbanju. 4) The varieties which were light in 1, 000 grains weight and poor in yield=Norin ＃29 and Sirogane. 2. The experiment on fertilization showed that the most desirable amount to be given per 10 Are was 10 kilograms of Nitrogen, 5 kilograms of phosphate and 6 kilograms of potassium; and when the Nitrogen given exceeded 8 kilograms, its effect was better when given in amsll consecutive (split) amounts, while the maturing ratio and the number of the flowers per panicle increased when Nitrogen was given in large amount during the later stage of growth of rice. 3. The experiment on the date and amount of seedling showed that the tested variety, Sunsou gave the best results when planted on the days between 25 April and 10 May. Eight liters per 10 Are were preferable if planted early and 12 liters per 10 Are if planted late. The reason why the later planting gave a lower yield was that the number of flowers per panicle was fewer. 4. The experiment on the irrigation for rice with direct sowing cultivation immersed in water showed that it was the most satisfactory when irrigated on 25th June, 55 days after its seedling, its plot giving the best yield. The plots 10th June and 15th July showed just as good results. However, irrigated later, than 15th July it showed lower yields. 5. Compared to the yield of the plot controlled by the common method, the yield from the plots treated with chemical herbicide such as LOROX, TOK, PCP, SWEP, Mo-338 on dry condition soil seemed poorer, but significant difference was not found statistically. On the other hand in the case where chemical herbicides such as TOK, Mo-338, Stam F-34 or ORDRAM were used after irrigation, the yield from the ORDRAM and TOK treated plots did not show significant differences compared to the common hand weed controling method, but those treated with chemicals other than the above showed a lower yield.