• Communications of the Korean Mathematical Society
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• v.31 no.2
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• pp.415-422
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• 2016

We derive a closed-form expression for the price of a European quanto call option when both foreign and domestic interest rates follow the Vasicek's short rate model.

• Quality Improvement in Health Care
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• v.20 no.1
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• pp.60-73
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• 2014

Objectives: This study aims at decreasing spatial dose rate through work improvement whilst spatial dose rate is the cause of increasing personal exposure dose which occurs in the process of handling radioisotope. Methods: From February 2013 until July 2013, divided into "before" and "after" the improvement, spatial dose rate in laboratory of nuclear medicine was measured in gamma image room, PET/CT-1 image room, and PET/CT-2 image room as its locations. The measurement time was 08:00, 12:00 and 17:00, and SPSS 21.0 USA was opted for its statistical analysis. Result: The spatial dose rate at distribution worktable, injection table, the entrance to the distribution room, and radioisotope storage box, which had showed high spatial dose rate, decreased by more than 43.7% a monthly average. The distribution worktable, that had showed the highest spatial dose rate in PET/CT-1 image room, dropped the rate to 42.3% as of July. The injection table and distribution worktable in the PET/CT-2 image room also showed the decline of spatial dose rate to 89% and 64.4%, respectively. Conclusion: By improving distribution process and introducing proper radiation shielding material, we were able to drop the spatial dose rate substantially at distribution worktable, injection table, and nuclide storage box. However, taking into account of steadily increasing amount of radioisotope used, strengthening radiation related regulations, and safe utilization of radioisotope, the process of system improvement needs to be maintained through continuous monitoring.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.3
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• pp.26-36
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• 2012

Minimizing the cylinder wear and the consumption rate of cylinder oil in a large two-stroke diesel engine is of great economic importance. A motor-driven cylinder lubricator for Sulzer RT-flex large two-stroke diesel engines developed by authors is in need of mounting a quill system to lubricate cylinder parts for a smooth operation. In order to apply the common-rail lubricating system to the developed cylinder lubricator as the second research stage, the mechanical quill system with a progressively quantitative distributor (M.D.S.) is improved in the electronically controlled quill system with an accumulating distributor (E.D.S.). In this study, the effects of lubricator motor speed, plunger stroke and cylinder back pressure on oil feed rate and inequality rate are experimentally investigated by applying E.D.S. to the developed cylinder lubricator. It is found that the oil feed rate of E.D.S. is higher than that of M.D.S. because of the increase of delivery speed and volume by changing the role of accumulator in the same experimental condition. It can be also shown that, in E.D.S., the inequality rate is decreased a little or hardly unchanged as the cylinder back pressure and plunger stroke is elevated, while the inequality rate increased in M.D.S.. The inequality rates of E.D.S. and M.D.S. are lowered as the lubricator motor speed is increased.

• Journal of Biosystems Engineering
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• v.39 no.4
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• pp.290-298
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• 2014

Purpose: To ascertain the increase of the farm income that predominantly relies on human resources by mechanizing Welsh onion harvesting, a tractor-mounted Welsh onion harvester was developed in this study. Method: An experiment for evaluating harvesting performance was performed for the developed Welsh onion harvester in an actual Welsh onion farm. The harvest performance was evaluated at the tractor running speeds of 5.0 cm/s, 11.4 cm/s and 15.8 cm/s, by comparing the operating efficiency, harvest rate, and damage rate of the Welsh onion harvester. Results: The performance of the harvester was rated as very good, with a 100% harvest rate, regardless of tractor running speed. Furthermore, it is shown that work efficiency of the harvester is expected to increase as the running speed increases. Nonetheless, the damage rate of the harvested Welsh onions at running speeds 5.0 cm/s, 11.4 cm/s, and 15.8 cm/s, increased correspondingly and proportionally to speeds from 4.55% to 6.53% and to 11.29%. The residual amount of soil on the harvested Welsh onions was about 0.24% of their weight showing excellent soil-removal performance of the harvester. Conclusion: The developed Welsh onion harvester is believed to improve the labor productivity and cultivation environment of Welsh onion farmhouses by the mechanization of the harvesting process that is currently associated with the largest amount of labor hours.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.04a
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• pp.559-562
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• 2004

In this paper, a new dual-rate digital control technique for the Takagi-Sugeno (T-S) fuzzy system is suggested. The proposed method takes account of the stabilizablity of the discrete-time T-S fuzzy system at the fast-rate sampling points. Our main idea is to utilize the lifted control input. The proposed approach is to obtain the dual-rate discrete-time T-S fuzzy system by discretizing the overall dynamics of the T-S fuzzy system with the lifted control, and then to derive the sufficient conditions for the stabilization in the sense of the Lyapunov asymptotic stability for this system.

• Journal of Oriental Neuropsychiatry
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• v.19 no.2
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• pp.133-139
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• 2008

Objective : The purpose of this research was to investigate the prevalence rate of Hwa-Byung for the whole population in a local community. Method : Hwa-Byung Diagnostic Interview Schedule(HBDIS) was carried out for 671 participants in Wonju Cohort study. HBDIS is objective questionnaire for diagnose Hwa-Byung. Collected data was analyzed by the chi-square test. Result: Prevalence rate of Hwa-Byung was 5.4% in the whole population. Prevalence rate of Hwa-Byung in male participants was 2.5%, 1.5% in 40s, 3.2% in 50s, 2.5% in 60s. Prevalence rate of Hwa-Byung in female participants was 7.4%, 7.6% in 40s, 5.5% in 50s, 8.7% in 60s. Conclusion : There was significant difference on the prevalence rate of Hwa-Byung according to sex.

• Journal of Genetic Medicine
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• v.9 no.1
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• pp.22-24
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• 2012

Purpose: The aim of this study was to asses the fetal loss rate after mid-trimester amniocentesis. Materials and Methods: This was a retrospective cohort study including singleton pregnant women who underwent mid-trimester amniocentesis at Cheil General Hospital from January 2008 through December 2010. The procedure-related fetal loss was defined as miscarriage within 2 weeks after amniocentesis. We evaluated the fetal loss rate within 2 weeks after amniocentesis and fetal loss rate before 24 gestational weeks. Results: During the study period, a total of 4,356 singleton pregnant women underwent mid-trimester amniocentesis. A total of Five hundred ninety six women were excluded owing to follow up loss and termination of pregnancy due to abnormal karyotype or major anomaly. At our institute, the fetal loss rate within 2 weeks was 0.1% and before 24 gestational weeks was 0.3% after amniocentesis. Conclusion: The fetal loss rate after mid-trimester amniocentesis in our study is lower than previously reported rate. We suggest that amniocentesis is a safe procedure.

• Korean Journal of Human Ecology
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• v.13 no.1
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• pp.29-40
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• 2004

The fertility rate of Korea has rapidly decreased to the lowest in the World. The fertility rate below replacement fertility level might result in many social problems. First, this study investigated the cause of low fertility rate. Second, the theories of the relationship between fertility rate and women's employment were reviewed. The previous studies suggested that the fertility rate was not always related to women's employment negatively and there was mediating factors between them. Third, the various factors that mediated the negative relationship between fertility rate and women's employment were described in personal, family and social levels. Finally, this study suggested the policies and strategies to solve the low fertility rate problem in Korea.

• Clinical and Experimental Reproductive Medicine
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• v.19 no.2
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• pp.163-168
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• 1992

This study was carried out to set up the ovum bank for ovum donation and to determine the best freezing method for human immature oocytes. Human immature follicular oocytes were cryopreserved by slow freezing and rapid thawing method. Immature follicular oocytes were treated by propanediol(PROH) solution by 2 and 4 step method in protocols A & B, respectively. In protocol C, immature oocytes were exposed to sucrose prior to treatment of PROH by 4 step method. We compared survival rate, maturation rate, and fertilization rate of immature oocytes among three protocols. Results were as follows. 1. Oocytes treated by the protocol C showed the highest survival rate( 70.3 %) and maturation rate(34.6%) after thawing. 2. Survival rate of oocytes treated by the protocol C was significantly higher than that of the protocol B after thawing(p<0.05). In conclusion, treatment of oocytes with sucrose prior to expose PROH was the best freezing method. Sucrose may have reduced the toxic effect of cryoprotectant to oocytes. We failed to induce fertilization of oocytes, which were treated by any protocols, by conventional insemination method, but obtained 28.8% fertilization rate by using partial zona dissection(PZD) method. This result suggests that micromanipulation(PZD) of the thawed oocytes before insemination will improve the fertilization rate.

• Asia-Pacific Journal of Business
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• v.5 no.1
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• pp.33-41
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• 2014

Since depositors are motivated by returns, it is important for Islamic banks management to understand the extent that rates of return on deposits influence their customers' decision to deposit. The main objective of the study is to explore the degree of influence of conventional bank's interest rate on Islamic bank's profitability and vice-versa. It has been seen from 2005 to 2011 that the rate of interest declared on deposit by conventional banks has a negative impact on profitability of both types of banks in Bangladesh. Rate of profit declared on deposit by Islamic banks is positively related with their profit earned but negatively related with profit earned by conventional banks. We see that rate of interest declared on deposit by Conventional Banks is positively related with their deposit volume but negatively related with Islamic Bank's deposit. On the other hand, rate of profit declared on deposit by Islamic Banks is negatively related with deposit levels of both types of banks. The survey result shows that almost 85% of the respondents are choosing Islamic banks only from their religious point of view and more than 60% of the sampled Islamic bank customers are reluctant to leave the bank even if conventional banks offer better interest rates.