• Economic and Environmental Geology
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• v.45 no.3
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• pp.277-294
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• 2012

The characteristics of temporal spacial radon variation in soil according to parent rock type and affecting factors were studied in Busan, Korea. The concentration of $^{222}Rn$ in soils and their parent elements ($^{226}Ra$,$^{228}Ra$, U and Th) in rocks and soils were measured at 24 sites in Busan area. The distribution and transportation behavior of these parent elements were analyzed and their correlations to radon concentration in soil were determined. Topographic effects were also evaluated. Two in-situ radon measurement (soil probe and buried tube) methods were applied to measure radon concentration in soil and their accuracies were evaluated. The spatial variation of radon in soil generally reflected U concentration in the parent rock. Average radon concentrations were higher in plutonic rocks than in volcanic rocks and were decreased in the order of felsic>intermediate>mafic rock. However, the radon concentrations were significantly varied in soils developed from same parent rocks due to the disequilibrium of U and $^{226}Ra$ between rock and soil. As results, the correlation of these element concentrations between rocks and soils was very low and radon concentrations in soils had highly co-related to the concentrations of these elements in soils. Th and $^{228}Ra$ show complex enrichment characteristics, differing significantly with U, in soils developed from same parent rock because the geochemical behavior of these elements during weathering and soil developing process was different with U. The radon concentrations in the same depth of soil in slope area were also different according to positions. The radon concentrations in soils developed from same parent rocks (19 sites at Pusan National University) varied 6.8~29.8Bq/L range because of small scale topographic variation. The opposite seasonal variation pattern of radon were observed according to soil properties. It was determined that buried tube method is more accurate method than soil probe method and was very advantageous application for the analysis for the characteristics of temporal spacial radon variation in soil.

• Clinical and Experimental Pediatrics
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• v.45 no.9
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• pp.1114-1119
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• 2002

Purpose : The purposes of this study were to determine short- and long-term fractal correlation behavior of heart rates during daily activity in patients with neurocardiogenic syncope. Methods : Twenty five patients with histories of neurocardiogenic syncope episodes were included. Their analogue 24h ambulatory Holter electrocardiograms were analyzed. The tape was digitized and the digitized electrocardiograms were partioned into sections of one hour. Then their RR intervals were measured and 20,000 points of RRI were used. To quantify the fractal correlation behavior, we employed the detrended fluctuation analysis, and short-term($n{\leq}16$, ${\alpha}_1$) and long-term(n>16, ${\alpha}_2$) fractal scaling exponents were calculated. Results : When compared to control, 24-hour average values of ${\alpha}_1$ and all ${\alpha}_1$ values at quarters of each day were significantly higher in patients with syncope. On the contrary, their 24-hour average value of ${\alpha}_2$ and all ${\alpha}_2$ values at quarters of each day were lower in patients with syncope. However, statistical significances were found in 24-hour average value of ${\alpha}_2$ and in ${\alpha}_2$ value at MN-6AM. Conclusion : In the syncope patients with neurocardiogenic syncope, short-term fractal scaling exponents of RR interval was significantly high throughout the day. Therefore, their RR intervals were smoother in the short term scale and had a tendency to continue in the same direction of increase or decrease, which may contribute to persistent decrease in heart rate during a syncopal attack.

• Journal of Korean Academy of Nursing
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• v.3 no.3
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• pp.1-14
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• 1973

This study is designed to meet the following objectives: (1) To study attitude and behavior regarding marriage and age at marriage, (2) To learn correlates of age at marriage and to examine their relations, (3) To measure relative importance of the correlates of age at marriage, and (4) To study relations of age at marriage and family planning practice to fertility and their relative importance as correlates of fertility. The data are obtained by an independent cross-sectional survey in three study areas purposively selected to represent metropolitan. semihuman. rural population. The study population is confined to women age 17-50 as of survey. The overall response rate is 90%. Reliability of data is measured by . individual and aggregate inconsistency based upon a 15% subsample of the original interviews. The individual inconsistency (31%) is found to be high compared to the aggregate inconsistency (6%) for all 85 variables. However, the magnitude of differences between means is small, and the mean absolute shifts and proportional shifts are also small on the whole. In a word respondents did not change their answers too extremely or radically. The study populations of each study area are compared on some basic characteristics. It is found that the three study populations have more dissimilarities than similarities. The findings on seven different attitudinal positions of women toward marriage indicate that there have been tremendous changes in all study areas Iron "traditional" attitudes which have been prevalent for a long time in Korean society to "liberalized" or "modernized" attitudes. An apparent tendency is that women generally take a position of a "golden mean" attitude by not preferring either extreme of marriage attitudes. Nevertheless, the young, single, educated, and urbanite appears more "liberalized. " There has been some increase in ideal age at marriage from 1958 to 1970 for both sexes. No age group, marital status, or study area differentials in ideal age at marriage are found, the average ideal age at marriage in every sub-group being 24-25. Awareness of existing legal marriageable ages is low; only 4.4% are aware that "with parental permission: minimum age for males is 18 years and for females 16 years,"and only 3.7% are aware that "without parental permission: 27 years for males and 23 years for females." People in Korra tend to marry spouses who are in various social ways like themselves: the similarities include (a) education, occupational status of father, (c) economic status, (d) usual residence before marriage, and (e) religion. Both singulars and actual mean ages at marriage in this study confirm the trend of rising age at marriage previously established by other independent studies. The urban-rural differential in age at marriage is observed, but the differential narrows down gradually from 1935 to 1970. All socio-economic, demographic, and other variables pertaining to wife before and at first marriage, excluding (a) religion, (b) father′s of occupation, and (c) as: of menarche, are correlated with respondent's age at first marriage, whereas only three variables out of all socio-economic variables relating to husband before and at wife′s first marriage, viz., (a) education, (b) usual residence, and (c) economic level of his old home, are correlated with respondent′s age at marriage. Among socio-economic and modernity variables related to either husband or wife at the time of survey, only education and duration of residence are correlated with wife′s age at first marriage. Among the correlates of respondent′age at first marriage, education is in general the most important variable. However, it is found that wife′s education is more important than husband′s. The combined effects or the correlates studied explain no more than about 40% of variance for any of the selected groups of variables. Points which might counteract the effects of late marriage on fertility are not serious in Korea. For each of the correlates of the three fertility indices chosen for this study. namely, (a) number of living children, (b) number of live births, and (c) number of pregnancies, age at marriage is the major contributor to the variance in all age groups except the age group of 20-29 in which the index of family planning practice is the major contributor. The proportion of variability in fertility indices accounted for by the correlates is never more than 40% of the total variance in any age group. Based upon the findings from this study, it could be concluded that in the foreseeable future (a) celibate group will no! be increased to a point that would slow down population growth rate in Korea, (b) age at marriage will not increase continually, (c) although education stands out as the major contributing variable which independently explains the variation in age at marriage, it seems probable that education may not be the major variable in the near future, and (d) despite the fact found by this study that age at marriages has been the major contributor to the variance of each of the fertility indices used, family planning practice will play a more important role in the reduction of fertility in the Korean society. Therefore, factors interrupting practice of family planning must be eliminated and family planning program should be strengthened if further fertility reduction is needed.

• Korean Business Review
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• v.13
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• pp.133-157
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• 2000

This paper investigate to construct a new strategic trading model which contains the broker and overconfident informed trader. Assuming more favorable situation for the broker, this paper construct a two period model. At period I overconfident informed trader and liquidity traders participate to trade. At this time the broker does not execute transaction of his own account. he only transfer customer's order by commission. At period 2, the broker identifies informed trade of previous period and he execute the trade of his own account with liquidity traders. The effects of overconfidence to the expected transaction volume and expected transaction profit, and price variability are summarized as follows: (i) As the degree of overconfidence increases, the expected transaction volume of informed trader increases. Under the restriction of moderate degree of overconfidence, it also increases the expected transaction volume of broker. In sum, overconfidence behavior of informed trader increases the expected transaction volume. (ii) As the degree of overconfidence increases, the both expected profit of informed trader and broker decrease. (iii) As the degree of overconfidence increases, unconditional variances of price for each periods increase. And as the degree of overconfidence increases, the informativeness of prices for each period increase. Finally, some limitations of this paper and direction for further research were suggested.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.3
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• pp.47-56
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• 2020

In this study, three levels of W/B(Water to Binder) ratio (0.37, 0.42, 0.47) and substitution ratio of GGBFS (Ground Granulated Blast Furnace Slag) rate (0 %, 30 %, 50 %) were considered to perform RCPT (Rapid Chloride Diffusion Test) at the 1,095 aged day. Accelerated chloride diffusion coefficient and passed charge of each concrete mixture were assessed according to Tang's method and ASTM C 1202, and improving behaviors of durability performance with increasing aged days are analyzed based on the test results of previous aged days from the preceding study. As the age of concrete increases, the passed charge and diffusion coefficient have been significantly reduced, and especially the concrete specimens containing GGBFS showed a significantly more reduction than OPC(Ordinary Portland Cement) concrete specimen by latent hydraulic activity. In the case of OPC concrete's results of passed charge, at the 1,095 days, two of them were still in the "Moderate" class. So, if only OPC is used as the binder of concrete, the resistance performance for chloride attack is weak. In this study, the time-parameters (m) were derived based on the results of the accelerated chloride diffusion coefficient, and the deterministic and probabilistic analysis for service life were performed by assuming the design variable as a probability function. For probabilistic service life analysis, durability failure probabilities were calculated using Monte Carlo Simulation (MCS) to evaluate service life. The service life of probabilistic method were lower than that of deterministic method, since the target value of PDF (Probability of Durability Failure) was set very low at 10 %. If the target value of PDF suitable for the purpose of using structure can be set and proper variability can be considered for each design variable, it is believed that more economical durability design can be made.