• Journal of Korea Water Resources Association
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• v.49 no.4
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• pp.275-282
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• 2016

The objective of this study is to propose a new method to determine the drought event and the design drought severity. In order to define a drought event from precipitation data, theory of run was applied with the cumulative rainfall deficit. When we have a large amount of rainfall over the threshold level, in this study, we compare with the previous cumulative rainfall deficit to determine whether the drought is relieved or not. The recurrence characteristics of the drought severity on the specific duration was analyzed by the conditional bivariate copula function and confidence intervals were estimated to quantify uncertainties. The methodology was applied to Seoul station with the historical dataset (1909~2015). It was observed that the past droughts considered as extreme hydrological events had from 10 to 50 years of return period. On the other hand, the current on-going drought event started from 2013 showed the significantly higher return period. It is expected that the result of this study may be utilized as the reliable criteria based on the concept of return period for the drought contingency plan.

• Journal of Labour Economics
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• v.30 no.1
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• pp.1-30
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• 2007

Using the Korean Labor and Income Panel Study 2001 (KLIPS 2001), this paper examines gender differences in the return to education in Korea. On average, there is little difference in return to education between male and female workers. However, this paper provides evidence that the impact of education on wages is greater for female workers compared to that for male workers using three different estimation strategies. First, a simple cohort analysis shows that the estimated returns to education for male and female workers have different patterns by age cohort and this is the main reason we observe little gap in average returns to education between men and women. Second, we find that college degree has a significant impact on women's labor market outcomes, while there is little gain for men in terms of wage levels by having college degree. Finally, when controlling unobservable individual ability level with test scores, education has no significant impact on male workers' wage levels, while the impact of education on wages is considerably large for female workers. All three findings support that the impact of education on labor market outcomes is greater for female workers compared to that for male workers as many researchers have found in other OECD countries.

• Journal of Korea Water Resources Association
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• v.33 no.3
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• pp.307-314
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• 2000

This study is to investigate the recurrence characteristics of wet and dry years using over 200 year records of annual rainfall depth including Chosun Age in Korea. As well as analyzing the correlation structure of the raw data, recurrence trends of wet and dry year has been investigated based on several truncation levels (mean, $mean{\pm}0.25stdv.,\;mean{\pm}O.5stdv.,\;mean{\pm}O.75stdv.,\;mean{\pm}stdv.$). Also the transition probability among wet, dry and normal years has been derived for the same truncation levels. and finally the average return periods based on the steady-state probabilities were obtained. This analysis has been applied to not only the entire data but also partial data set of before- and after-the long dry period around 1900 in order to compare and detect the possible difference between the Chukwooki (an old raingauge invented in Chosun age) and the modem flip-bucket style. As a result, Similar pattern of dry and wet year recurrence has been found, but the return period of extremely dry years after the dry period shown longer than that before the dry period. Assuming that the dry and wet years can be defined as $mean{\pm}$ standard deviations, respectively, the return period of the wet years is shown to be about 5~6 years and that of the dry years about 6~7 years.

• Journal of Embryo Transfer
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• v.18 no.3
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• pp.257-262
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• 2003

These studies were performed to improve the reproductive efficiency of gilts and we investigated the effects of nursing periods after parturition and backfat thickness will adapt to these results for early selection of excellent gilts. The main results were as follows; 1. The backfat thickness in sows nursing for 17∼21 days was 19.19 mm, and 16.52 mm in 22∼26 days and longer nursing period affected significantly the backfat thinner (p<0.01). 2. The recurrence of estrus in sows nursing for 17∼21 days was 5.76 day and 5.62 day in 22∼26 days and there was no difference between nursing periods. 3. The recurrence of estrus in sows had 13∼16 mm backfat thickness was 5.69 day, 5.67 day in 17∼20 mm and 5.75 day in 21∼23 mm and there was no difference among backfat thickness. 4. The concentration of plasma estradiol were 28.49 pg/$m\ell$ in parturition, 12.39 pg/$m\ell$ in weaning and 16.52 pg/$m\ell$ in return of estrous. The concentration ot plasma progesterone were 1.50 ng/$m\ell$ in parturition, 0.69 ng/$m\ell$ in weaning and 0.94 ng/$m\ell$ in return of estrous. The concentration of plasma cortisol were 57.74 ng/$m\ell$ in parturition, 43.01 ng/$m\ell$ in weaning and 47.89 ng/$m\ell$ in return of estrous. There showed the highest level of estradiol, progesterone and cortisol in parturition.

• International journal of advanced smart convergence
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• v.11 no.1
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• pp.19-27
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• 2022

Across the world, 'housing' comprises a significant portion of wealth and assets. For this reason, fluctuations in real estate prices are highly sensitive issues to individual households. In Korea, housing prices have steadily increased over the years, and thus many Koreans view the real estate market as an effective channel for their investments. However, if one purchases a real estate property for the purpose of investing, then there are several risks involved when prices begin to fluctuate. The purpose of this study is to design a real estate price 'return rate' prediction model to help mitigate the risks involved with real estate investments and promote reasonable real estate purchases. Various approaches are explored to develop a model capable of predicting real estate prices based on an understanding of the immovability of the real estate market. This study employs the LSTM method, which is based on artificial intelligence and deep learning, to predict real estate prices and validate the model. LSTM networks are based on recurrent neural networks (RNN) but add cell states (which act as a type of conveyer belt) to the hidden states. LSTM networks are able to obtain cell states and hidden states in a recursive manner. Data on the actual trading prices of apartments in autonomous districts between January 2006 and December 2019 are collected from the Actual Trading Price Disclosure System of the Ministry of Land, Infrastructure and Transport (MOLIT). Additionally, basic data on apartments and commercial buildings are collected from the Public Data Portal and Seoul Metropolitan Government's data portal. The collected actual trading price data are scaled to monthly average trading amounts, and each data entry is pre-processed according to address to produce 168 data entries. An LSTM model for return rate prediction is prepared based on a time series dataset where the training period is set as April 2015~August 2017 (29 months), the validation period is set as September 2017~September 2018 (13 months), and the test period is set as December 2018~December 2019 (13 months). The results of the return rate prediction study are as follows. First, the model achieved a prediction similarity level of almost 76%. After collecting time series data and preparing the final prediction model, it was confirmed that 76% of models could be achieved. All in all, the results demonstrate the reliability of the LSTM-based model for return rate prediction.

• Fisheries and Aquatic Sciences
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• v.1 no.2
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• pp.255-259
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• 1998

This study was designed to evaluate the economic analysis of channel catfish production in 1998 based on fish value and total feed cost. Catfish received higher protein feeds with lesser amount based on the dietary protein levels, but received the constant total protein input for all treatments. Weight gain per pond for treatment 1 $(28\%\;protein,\;100\%\;of\;satiation)$ was higher (P<0.10) than for treatment 3 $(36\%\;protein,\;77.8\%\;of\;satiation)$, but not significantly higher than for treatment 2 $(32\%\;protein,\;87.5\%\;of\;satiation)$ at constant DE. At constant DE/P (treatments 4, 2 and 5), weight gain per pond for treatment 5 $(36\%\;protein,\;77.8\%\;of\;satiation)$ was lower (P<0.10) than for treatment 2, but not significantly lower than for treatment 4 $(28\%\;protein,\;100\%\;of\;satiation)$. At constant DE, feed conversion slightly improved as dietary protein level increased from $28\%\;to\;32\%$ and feed allowance decreased by $12.5\%$, but did not improve further as dietary protein level increased from $28\%\;to\;36\%$ and feed allowance decreased by $22.2\%$. At constant DE/P, feed conversion improved as dietary protein level increased from $28\%\;to\;32\%$ increased and feed allowance decreased by $12.5\%$, but did not improve as dietary protein level increased from $28\%\;to\;36\%$ and feed allowance decreased by $22.2\%$ Total feed cost for treatment 1 was slightly, but not significantly higher than for treatments 2 and 3 at constant DE. At constant DE/P, total feed cost for treatment 5 was higher (P<0.05) than for treatment 2, but not significantly higher than for treatment 4. Total value of fish ($ /ha) produced for treatment 1 was highest and lowest was for treatment 5. Return above feed cost was highest for treatment 1 and nearly the same as treatment 2. Return over feed cost for treatments 3 and 4 were slightly lower than for treatments 1 and 2. Economic analysis showed that feeding fish the diet containing $28\%$ protein and 3.08 kcal/g DE to satiation and the diet containing $32\%$ protein and 3.08 kcal/g DE to $87.5\%$ of satiation produced the highest profit to farmer.

• The Korean Journal of Financial Management
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• v.22 no.1
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• pp.119-146
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• 2005

This study applies extreme value theory to get extreme value-VAR for Korean Stock market and showed the usefulness of the approach. Block maxima model and POT model were used as extreme value models and tested which model was more appropriate through back testing. It was shown that the block maxima model was unstable as the variation of the estimate was very large depending on the confidence level and the magnitude of the estimates depended largely on the block size. This shows that block maxima model was not appropriate for Korean Stock market. On the other hand POT model was relatively stable even though extreme value VAR depended on the selection of the critical value. Back test also showed VAR showed a better result than delta VAR above 97.5% confidence level. POT model performs better the higher the confidence level, which suggests that POT model is useful as a risk management tool especially for VAR estimates with a confidence level higher than 99%. This study picks up the right tail and left tail of the return distribution and estimates the EVT-VAR for each, which reflects the asymmetry of the return distribution of the Korean Stock market.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.12
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• pp.863-867
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• 2020

This study was conducted on financial data of 38 economic groups listed on Vietnam's stock market for the period 2009 - 2019 and it aims to provide an empirical evidence on the impact of working capital management policy on performance in all phases of the economic cycle of Vietnamese economic groups. The study uses FGLS estimation method with 2 dependent variables ROA, GOP, independent variables including INV, AR, AP, CCC, dummy variable representing different phases of the economic cycle, variables Control includes CAT, CR, LEV, SZ, GR. Research shows that the greater the level of investment by companies in liquid assets corresponding to a certain level of activity (shown by average days of inventory (INV), average days of collection. (AR), cash flow cycle (CCC)) the lower the rate of return on assets. The study also provides additional evidence of the negative effects of economic crisis on the performance of economic groups. The study also shows that the number of short-term asset cycles has a positive impact on operational efficiency, and the level of debt use has a negative impact on operational efficiency. This result implies that the managers of economic groups can increase the efficiency of businesses through a reasonable working capital policy.

• Korean Journal of Organic Agriculture
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• v.26 no.3
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• pp.327-349
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• 2018

The purpose of the study focuses on the agriculture education services in the changing rural areas conditions such as population decline, aging society, and returning farmers. The study reviews the effects of agricultural education services on returning farmers and local residents for satisfaction, intention for recommendation, and intention to continue participation. Further, the study aims to investigate any difference in the level of satisfaction for two groups. The results suggested that there is a meaningful difference between return-farmers and local residents. Among the demographic variables, age and income showed a notable difference. However, sex, level of education and type of household did not suggest noticeable differences. In addition, the study accessed agricultural education from a service perspective and analyzed its service quality and customer satisfaction, loyalty and relationship using a service profit chain model. Like the result of most other studies, the analysis showed that these had positive relationships. While the study focused on the efficiency of agriculture education training program in agriculture technology centers, the study carries a meaningful value in that it discovered a meaningful difference in the satisfaction level between returning farmers and locals despite the fact that agriculture education was applied as a part of service. In practical terms, the study pointed out the need for consumer-centered education that reflects the characteristics of the groups rather than standardized education.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.4
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• pp.27-35
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• 2019

The paper examines the level of disclosure on Islamic banks' performance in the United Arab Emirates (UAE). The data was collected through content analysis of annual reports and financial statements of all fully-fledged Islamic banks working in the UAE over the period 2009 to 2013. Return on Assets is used as a proxy for the performance of Islamic banks while disclosure index is used as a proxy for Islamic banks' disclosure. Also, predetermined variables are used in the study like Size, Deposits, Non-Performing Investments and Capital to Risk Weighted Assets Ratio. Two-Stage Least-Square regression method is used to check the interdependence relationships between disclosure and performance of Islamic banks in the UAE. The results show a significant relationship between performance and disclosure in the UAE Islamic banks. Our regression results show that Islamic banks with higher levels of disclosure lead to higher operating performance. Furthermore, the performance has a great impact on the level of disclosure which means Islamic banks with high performance measures will disclose more information for investors and other institutions in order to reduce the cost of equity and increase their values in the market. This study is considered as a battery for further studies in the relationship between disclosure and financial performance of Islamic banks at a global level.