• Journal of Veterinary Clinics
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• v.28 no.6
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• pp.571-575
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• 2011

Sperm cryopreservation methods have been improved over the last few decades. However, an optimized thawing rate has not yet been established. Therefore, we investigated the effect of thawing rate on sperm function after cryopreservation. The ejaculates collected from beagle dogs were cryopreserved and then thawed at two different thawing rates ($37^{\circ}C$ for 1 min or $70^{\circ}C$ for 15 sec). The thawed sperm were evaluated for motility, viability, morphology, plasma membrane integrity, phosphatidylserine (PS) translocation, and intracellular $H_2O_2$ level. The sperm thawed rapidly at $70^{\circ}C$ showed improved motility, viability, normal morphology, plasma-membrane integrity and non-PS translocation compared to the sperm thawed slowly at $37^{\circ}C$ (P < 0.05). However, the intracellular $H_2O_2$ levels were not significantly different between the rapid- and slow-thawed sperm (P > 0.05). In conclusion, sperm rapid thawing at $70^{\circ}C$ could improve the function of cryopreserved canine sperm, and the appropriate thawing rate would enhance the quality of the cryopreserved sperm.

• Journal of Korean Society of Rural Planning
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• v.22 no.3
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• pp.119-129
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• 2016

The aim of this study is to suggest the quantitative standard of a marginal village. For the purpose, the study selected 43 villages with the population of 50 or less, the classification of a marginal village in accordance with advanced research and 47 villages with the population over 50 in Buyeo-gun region. The common reason of occurrence of a marginal village suggested by advanced research is a characteristic of a village or decline and extinction of a village rather than a simple index of population or aging rate. Therefore, the study assumed that decline of functions of the village would be caused by decline a function of communities consisting of the villagers. The study then assumed that the relatively low or 0 number or rate of participants would result in community functions. The study conducted t-test on basis of population and aging rate and an analysis to find the range with relatively large differences in the number of communities, participants and the rate of the participants, etc. The result showed that the community function began to decline when the population was less than 60~70 and the aging rate over 75%~85%. As the decline of functions of communities began in population of 70, the critical point was met when the population was 40 or less. With population of 40 or less, the young and the old group communities became extinct or showed rapid decrease in the number of participants. The study assumed that decline of functions of a village, a reason of occurrence of a marginal village would be decline of functions of communities, but there was no further analysis on decline or extinction of a village with population of 40 or less. There shall be further studies about whether a village of population of 40 or less is led to decline of a function or extinction of village communities.

• Korean Journal of Psychosomatic Medicine
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• v.21 no.1
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• pp.55-61
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• 2013

Objectives : Alzheimer's disease(AD) and mild cognitive impairment(MCI) affect several nervous structures involved with the autonomic nervous system. Association between neuropsychiatric deficits and heart rate variability has been observed. But cardiac autonomic function in AD has been scarcely studied and the results reported are conflicting. We investigated autonomic function in normal control, MCI, AD using heart rate variability(HRV) technique. Methods : Time and frequency-domain variability of 5-min R-R interval series was comparatively evaluated in 26 normal control subjects, 22 MCI subjects and 34 AD subjects. Analysis of variance(ANOVA) was used to compare the differences across groups. Correlations between MMSE-KC and HRV components were performed using Pearson's correlation coefficient. Results : No significant difference was observed among the groups in time, frequency-domain analysis of HRV(p>0.05). HRV were not found to be significantly correlated with the degree of cognitive impairment. Conclusions : There were no differences in HRV with MCI, AD subjects when compared with normal controls. Further investigation is required to use HRV technique as noninvasive parameters of MCI and AD.

• KDI Journal of Economic Policy
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• v.13 no.4
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• pp.59-90
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• 1991

The purpose of this paper is to determine whether the rate schedule of the Korean income tax system embodies the theoretically desirable distribution of the tax burden by income classes. The paper follows the approach of Young (1990) who has estimated the utility function and calculated the magnitude of sacrifice, i.e., the tax burden. The main point of the study is to estimate the utility function. The estimation results may differ if different data sets are used. Therefore, this paper employs the effective as well as the nominal tax rate schedule. The findings derived in this paper are 1) that the effective rate schedule is more appropriate in estimating the utility function; 2) that the middle class has born the relatively heavier burden over time; 3) that the current income tax credit scheme curtails the tax burden on the middle class while intensifying the tax burden of the lower and upper income classes; 4) that reducing the amount of deduction moves the distribution of tax burdens by income classes closer to the theoretically desirable model; 5) that the rate schedule of the Korean income tax system, particularly in 1991, did not conform to the desired model as did the tax systems of developed countries such as the United States, Italy, Japan, and Germany.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.4
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• pp.191-201
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• 2016

A stochastic process has been used to develop a condition-based model for preventive maintenance of armor units of rubble-mound breakwaters that can make a decision the optimal interval at which some repair actions should be performed under the perfect maintenance. The proposed cost model in this paper based on renewal reward process can take account of the interest rate, also consider the unplanned maintenance cost which has been treated like a constant in the previous studies to be a time-dependent random variable. A function for the unplanned maintenance cost has been mathematically proposed so that the cumulative damage, serviceability limit and importance of structure can be taken into account, by which a age-based maintenance can be extended to a condition-based maintenance straightforwardly. The coefficients involved in the function can also be properly estimated using a method expressed in this paper. Two stochastic processes, Wiener process and gamma process have been applied to armor stones of rubble-mound breakwaters. By evaluating the expected total cost rate as a function of time for various serviceability limits, interest rates and importances of structure, the optimal period of preventive maintenance can easily determined through the minimization of the expected total cost rate. For a fixed serviceability limit, it shows that the optimal period has been delayed while the interest rate increases, so that the expected total cost rate has become lower. In addition, the gamma process tends to estimate the optimal period more conservatively than the Wiener process. Finally, it is found that the more crucial the level of importance of structure becomes, the more often preventive maintenances should be carried out.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.133-138
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• 2018

Safety management has become even more important because of the safety and environmental issues that have arisen since the 2000s. However, the safety study requires many empirical data, so there are many limitations. In the case of pipe safety, simulation programs exist, but it is difficult to get data about the pipe internal erosion of the pipe. In this study, the erosion rate of the pipe elbow was simulated using computational fluid dynamics (CFD). Also, the failure period of the pipe was calculated by the limit state function using erosion rate. In the case of CFD pipe, a sample which is actually operated in Yeosu industrial complex was used, and the geometry and mesh formation were rationalized in terms of typical fluid dynamics simulations. Using the Discrete Phase Model (DPM) and the corrosion model, the erosion rate ($3.09227mm{\cdot}yr^{-1}$) was obtained from CFD simulations. As a result of applying the erosion rate to the limit state function, we obtained the pipe failure period value, 14.2 years to trigger a leak and 28.2 years to trigger a burst. Through these processes, we concluded that pipe erosion is one of the major failure modes. In addition to the results, this study has significance for suggesting the methodology of the pipe safety study.

• The Journal of Korean Medical History
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• v.28 no.2
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• pp.37-45
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• 2015

Objectives : A quantitative analysis on the vocabulary in the English translation version of Donguibogam. Methods : This study quantitatively analyzed the English-translated texts of Donguibogam with the Corpus-based analysis, and compared the quantitative results analyzing the texts of original Donguibogam. Results : As the results from conducting the corpus analysis on the English-translation version of Donguibogam, it was found that the number of total words (Token) was about 1,207,376, and the all types of used words were about 20.495 and the TTR (Type/Token Rate) was 1.69. The accumulation rate reaching to the high-ranking 1000 words was 83.54%, and the accumulation rate reaching to the high-ranking 2000 words was 90.82%. As the words having the high-ranking frequency, the function words like 'the, and of, is' mainly appeared, and for the content words, the words like 'randix, qi, rhizoma and water' were appeared in multi frequencies. As the results from comparing them with the corpus analysis results of original version of Donguibogam, it was found that the TTR was higher in the English translation version than that of original version. The compositions of function words and contents words having high-ranking frequencies were similar between the English translation version and the original version of Donguibogam. The both versions were also similar in that their statements in the parts of 'Remedies' and 'Acupuncture' showed higher composition rate of contents words than the rate of function words. Conclusions : The vocabulary in the English translation version of Donguibogam showed that this book was a book keeping the complete form of sentence and an Korean medical book at the same time. Meanwhile, the English translation version of Donguibogam had some problems like the unification of vocabulary due to several translators, and the incomplete delivery of word's meanings from the Chinese character-culture area to the English-culture area, and these problems are considered as the matters to be considered in a work translating Korean old medical books in English.

• Journal of Navigation and Port Research
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• v.44 no.3
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• pp.145-150
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• 2020

The ship motion of large LNG ships affects ships' safety. The purpose of this study was to estimate the transfer function of roll motion among the hull motion of 153,000 m3 class LNG vessels. The ship motion transfer function was modeled using a Linear Time-Invarient system with single input, single output, and transfer function. The transfer function of the ship motion was estimated by the system identification method using single ocean wave as input of the model, and using the roll motion of the LNG ship obtained through ANSYS as the output of the model. The usefulness of the experimental results was evaluated using the precision and estimation rate of the model for cases wherein the different transfer function dimensions. Results of the experiment showed a precision at 99% and 98%, with estimation rate at 78% and 50%. From these results, we found the proposed method of estimating the transfer function of ship motion in this study reasonable. In the future, data of ship motion in actual sea conditions will be acquired and it will be applied to make the construction of models with multiple inputs and multiple outputs for practical use.

• The Korean Journal of Nuclear Medicine
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• v.8 no.1_2
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• pp.29-37
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• 1974

The $^{99m}Tc$-pertechnetate thyroid uptake rates(20 min) were measured in 24 healthy normal subjects, 140 patients with nontoxic goiter and 98 patients with thyrotoxicosis who were treated at the Thyroid Clinic, Seoul National University Hospital, from August 1972 to August 1973. Diagnostic reliabilities and correlations between $^{99m}TcO_4$-thyroid uptake rate (20 min) and other thyroid function tests were evaluated. The observed results were as follows 1. The $^{99m}TcO_4$-thyroid uptake rates (20 min) in normal subjects, euthyroid group and hyperthyroid group were $4.1{\pm}0.9%,\;5.2{\pm}1.8%\;and\;29.7{\pm}10.6%$. There was a significant difference between the mean of the euthyroid group and the mean of the hyperthyroid group and so differentiation between them can be easy. 2. In the diagnosis of hyperthyroidism, the reliabilities of $^{99m}TcO_4$- thyroid uptake rate(20 min), $^{131}I$ thyroid uptake rate(24hrs), serum $T_3$ resin uptake rate, serum $T_4\;and\;T_7\;were\;87.9{\sim}97.9%,\;81.2{\sim}94.4%,\;87.9{\sim}97.9%,\;90.5{\sim}99.3%\;and\;93.7{\sim}100%$. $^{99m}TcO_4$-thyroid uptake rate(20 min) is more accurate than $^{131}I$ thyroid uptake rate (24 hrs) in the diagnosis of hyperthyroidism. 3. $^{99m}TcO_4$-thyroid uptake rate (20 min) was well correlated with $^{131}I$ thyroid uptake rate (24 hrs), serum $T_3$ resin uptake rate, serum $T_4\;and\;T_7$. Points in favor of $^{99m}Tc$ are that it gives a small radiation dose to the thyroid, that tests can be repeated at the short interval, the study can be completed at a single patient visit and it is particularly well suited for the assessment of thyroid function in patients being treated with an antithyroid drug.

• JSTS:Journal of Semiconductor Technology and Science
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• v.4 no.4
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• pp.286-292
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• 2004

In this paper we present a static performance estimation technique of on-chip bus architectures. The proposed technique requires the static scheduling of function blocks of a task to analyze bus conflicts caused by simultaneous accesses from processing elements to which function blocks are mapped. To apply it to multitask applications, the concurrent execution of the function blocks of different tasks also should be considered. Since tasks are scheduled independently, considering all cases of concurrency in each processing element is impractical. Therefore we make an average estimate on the effects of other tasks with respect to bus request rate and bus access time. The proposed technique was incorporated with our exploration framework for on-chip bus architectures, Its viability and efficiency are validated by a preliminary example.