• Korean Journal of Poultry Science
• /
• v.48 no.2
• /
• pp.91-100
• /
• 2021

The study determined the effects of stock density (SD) and energy level (EL) on growth performance, serum biochemistry, and meat quality in Korean native chickens. A total of 240 chickens were randomly assigned to one of the four treatments including two stock density (low, 14, and high, 16 chickens per m²) and two energy level (low, 2,950, 3,000, 3050 ME kcal/kg, and high 3,150, 3,200, 3,250 ME kcal/kg, for starter, grower, and finisher, respectively). During the whole period of the experiment, the chickens were fed ad libitum. The greater final body weight and weight gain were achieved in chickens fed high energy diet, whereas the final body weight and weight gain were significantly reduced in high-density treatment compared with the low density. Chickens in low-density groups had a higher feed intake compared with high-density treatment, however, the energy level did not affect the feed intake. An improved overall feed conversion ratio was detected in the high energy treatment. There was a significant interaction between stock density and energy level on cholesterol concentration. The concentration of aspartate transaminase in serum was increased by higher stock density. There was a significant treatment interaction on IgM levels. Moreover, the carcass rate was significantly increased in the high energy level treatment. Based on the findings, we suggest that rearing chickens in low density with high dietary energy levels could be beneficial by improving the growth performance.

• Communications for Statistical Applications and Methods
• /
• v.25 no.4
• /
• pp.397-409
• /
• 2018

The world financial markets are inter-linked in ways that varies according to market and time. We examine the causality of change focusing on the Korean market as related to the U.S. (S&P 500), Japan (Nikkei 225), Hong-Kong (HSI), and European (DAX) markets. In order to capture time-varying causality running from and to the Korea stock market, we apply the Granger causality test under a VAR model with a wild bootstrap rolling-window approach. We also propose a new concept of a significant causality ratio to measure the intensity of the Granger causality in each time unit. There are many asymmetric strengths in mutual Granger causal relationships. Moreover, there are cases with significant Granger causal relations only in one direction. The period with the most severe Granger causality both running from and to the KOSPI market is the GFC. The market that formed the two-way Granger causal relationship with the KOSPI market for the longest period is the S&P 500. The HSI and DAX markets have the strongest two-way Granger causal relationship with the KOSPI shortly after 2000, and the Nikkei market had the strongest two-way Granger causal relationship with the KOSPI market before the Asian financial crisis.

• Journal of Korean Society of Forest Science
• /
• v.32 no.1
• /
• pp.1-8
• /
• 1976

One of the most common needle leaf species used in planting in Korea is korean pine (Pinus koraiensis S. et Z.), and jack pine (Pinus banksiana Lamb.) is one of the test species for suitability. The relation of nursery bed density of 2-1 korean pine and 1-1 jack pine was studied at the Kwang Nung Nursery, Central Branch Station of Forest Research Institute, and about 40km north of Seoul. Nursery bed density of 2-1 korean pine, which ranged from 36 to 324 trees per square meters and of 1-1 jack pine, which ranged from 25 to 169 trees per square meters, had a marked effect on caliper, height, dry weight and percent and amount of plantable stock. The soil physical and chemical properties is silt plus clay, 50.55 percent; organic matter, 2.09 percent; total nitrogen, 0.13 percent; available phosphorus, 253.25 ppm; exchangeable potash, 0.46 m.e/100g; and pH, 5.58. As the density of the nursery seedling stand of 2-1 korean pine increases, the average tree height increases (Fig. 1A), but in 1-1 jack pine density do not affect to increase or decrease the average tree height. As the density of nursery bed increases, the average stem caliper (at 2cm above ground line) and dry weight decrease (Fig. 1B), but the decreasing rate is more seriously in 1-1 jack pine than 2-1 korean pine (Fig.5). As increasing the density of nursery bed, the T/R ratio of trees of the test species increase. Also the dry weight of leaf, stem and root parts are decreasing in proportion to the increase of stand density, but the drop rate of jack pine is more rapid than korean pine (table. 1) The patent facts of difference of growth characteristics between 2-1 korean pine and 1-1 jack pine were studied. These facts should be used to select the scale of stand density at the nursery bed or the plantable site. Korean pine is demanded high density, on the other hand in jack pine low density are more suitable to manage the stand density. Stands of comparatively low density had the greatest percentage of high-quality stock, and the stands of high density had less than the high quality trees of low density. An important criterion of the best density is percent and number of high-quality trees produced per square meter of bed area. Stem caliper and stem height of seedling is used in most public nurseries to sort seedling into plantable grades. The stock grade standard has set at 4.5mm caliper and 16cm height of 2-1 korean pine as the minimum desired stem caliper and height. By the result studies, the plantable stock grade standards of 2-1 korean pine used at stem height 16cm and stem caliper 4.5mm from public nurseries should be reformed to stem height 18cm and stem caliper 4.0mm by the growth characteristics and the tree distribution of stem height and caliper of relation to density. For the 2-1 korean pine, best density should be about 160 to 200 trees per square meter according to soil fertility. For the 1-1 jack pine, the suitable standard of plantable stock should be at stem height 25cm and caliper 6mm (at 2cm above ground line) and best density was about 100 to 120 trees.

• Plant Disease and Agriculture
• /
• v.1 no.1
• /
• pp.30-36
• /
• 1995

Infection rate of witches'-broom disease (WB) was observed yearly in transplanted jujube seedlings for 7 years. Seedlings of‘Hongan’grafted either on the rootstock from seed (RS) or on the rootstock from rooting (RR) were planted in separate farms. Occurrence of the disease was determined 4 years after transplanting with the witches'-broom symptom. Only 1 seedling of RS was infected with WB, while 56 seedlings of RR showed WB. Yearly infection rates of WB were observed in several varieties of jujube including‘Boeun’,‘Keumsung’,‘Moodeung’,‘Bokjo’,‘Koori’(10 trees for each in Cheongjoo), and‘Hongan’(165 trees in Boeun). In most varieties, WB first appeared in the third year from transplanting, and in the seventh year, more than 80% of the total tree showed WB. The yearly infection rate of newly infected trees was almost. stable during the first years. However, the ratio sharply increased from the sixth year. The accumulated infection rate of WB increased double, year by year from the third to seventh year. Between Cheongjoo and Boeun, no difference in infection rates was found.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.13 no.4
• /
• pp.266-273
• /
• 2003

The purpose of this study is to obtain the effects of the parameters of the suspension system in railway rolling-stock for KT-23 type Passenger vehicle. According to the analysis and the small scale model car test. optimal condition was obtained for the stiffness ratio of secondary spring to primary spring of the suspension system and the mass ratio of the bogie frame to the car body. The analysis of the study shows that if the car body mass is increased or secondary stiffness Is lowered, the vertical vibration level is reduced and the passenger comfort can be improved. Especially, strong peaks are occurred in the frequencies corresponding to the rotational speed of driving axle and vehicle wheel. Hence, in order to obtain the dynamic characteristics through the small scale model car, the driving method of the vehicle on the test bench, rotational characteristics of the wheel and the natural modes of vehicle should be investigated and be modified.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.10
• /
• pp.47-56
• /
• 2021

It is unavoidable for businesses, especially commercial banks, to compete with other firms and financial institutions in a globalized and internationalized world. Basel I, II, and III were developed by the Basel Committee on Banking Supervision with the primary purpose of supporting banks in dealing with potential risks and enhancing their ability to absorb losses. Basel II and III require the minimum capital adequacy ratio (CAR) of 8% and 10.5%, respectively. This paper estimates the optimal CAR of 26 commercial banks in Vietnam from 2016 to 2020 using the two-stage DEA method. According to the empirical findings, banks with ideal CARs exceeding 8% (as defined by Basel II) and 10.5 percent (as defined by Basel III) account for approximately 98 percent and 88 percent of all banks, respectively. Furthermore, 75.83 percent of all banks need to boost their existing CAR to achieve the optimal level of CAR as well as obtain the best performance. On average, the optimal CAR of state-owned banks is higher than other joint-stock banks, respectively 26 percent and 19 percent. Consequently, it is recommended for Vietnam commercial banks to reach optimal CAR and comply with the new policy set by Basel III with the purpose of approaching the efficient frontier.

• Ocean and Polar Research
• /
• v.32 no.4
• /
• pp.483-488
• /
• 2010

Since 2000 fry releasing programs in Korea have significantly expanded in order to support the commercial fishing industry through recruitment enhancement of targeted species. Here we investigate the economic effectiveness of the Olive flounder (Paralichthys olivaceus) fry releasing program in Korean waters. The market survey method was used in our analyses. Results show that the B/C ratio, as an indicator of economic evaluation, is 2.56 in the East Sea region, 9.45 in the South Sea region, and 1.34 in the West Sea region, which indicates that the fry releasing program is economically feasible but the economic effectiveness varies from region to region.

• The Korean Journal of Food And Nutrition
• /
• v.4 no.2
• /
• pp.141-148
• /
• 1991

In order to Investigate the extraction mechanism of barley tea in cylindrical packed column, pilot plant scale packed column was designed and constructed. And extraction conditions for steady flow in the packed column were searched. The main results of this study are as follows ; 1. Circulation of the stock barley tea before the extraction running was indispensable In consideration of inequality, gas, particles existed in packed bed. Solid-liquid equilibrium was initially maintained after the circulation. 2. Flow direction of solvent must be up-flow for maintaining the constant bed height and flow rate during the extraction. Paessure drop in pucked bed was similar to decrease ratio of extract concentration. 3. The porosity of packed bed was in the range of 0.24∼0.36 according to the particle sloe. And it was decreased as the particle size became smaller.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.11 no.1
• /
• pp.57-61
• /
• 1998

In this study, PLZT stock solutions were prepared by Sol-Gel processing after the compositions were selected in the memory region of PLZT bulk phase diagram. PLZT solutions were deposited on the ITO glass substrate by spin-coating method. The thin films were annealed by rapid thermal processing. The electric characteristics, hysteresis loop, C-V characteristics of thin films in the memory region were measured in order to investigate the electrical characteristics of PLZT thin films. In selected compositions the decrease in Zr/Ti ratio led to an increase in dielectric constant and the decrease in remanent polarization and coercieve field which brought about slim hysteresis loop.

• Journal of Korean Society for Quality Management
• /
• v.51 no.2
• /
• pp.171-184
• /
• 2023

Purpose: First, this paper suggests an alternative approach to find optimal portfolio (stocks, bonds and ESG stocks) under the maximizing utility of investors. Second, we include ESG stocks in our optimal portfolio, and compare improvement of welfares in the case with and without ESG stocks in portfolio. Methods: Our main method of analysis follows Brennan et al(2002), designed under the continuous time framework. We assume that the dynamics of stock price follow the Geometric Brownian Motion (GBM) while the short rate have the Vasicek model. For the utility function of investors, we use the Power Utility Function, which commonly used in financial studies. The optimal portfolio and welfares are derived in the partial equilibrium. The parameters are estimated by using Kalman filter and ordinary least square method. Results: During the overall analysis period, the portfolio including ESG, did not show clear welfare improvement. In 2017, it has slightly exceeded this benchmark 1, showing the possibility of improvement, but the ESG stocks we selected have not strongly shown statistically significant welfare improvement results. This paper showed that the factors affecting optimal asset allocation and welfare improvement were different each other. We also found that the proportion of optimal asset allocation was affected by factors such as asset return, volatility, and inverse correlation between stocks and bonds, similar to traditional financial theory. Conclusion: The portfolio with ESG investment did not show significant results in welfare improvement is due to that 1) the KRX ESG Leaders 150 selected in our study is an index based on ESG integrated scores, which are designed to affect stability rather than profitability. And 2) Korea has a short history of ESG investment. During the limited analysis period, the performance of stock-related assets was inferior to bond assets at the time of the interest rate drop.