• Management & Information Systems Review
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• v.30 no.2
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• pp.257-275
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• 2011

The price relationship between the futures market and the underlying spot market has attracted the attention of academics, practitioners, and regulators due to their roles during periods of turbulence in financial markets. The purpose of this paper is to investigate the dynamic of price relationship(or lead-lag relationship) between Korean Treasury Bond futures market and spot market. To examine the nature of the price relationship, descriptive statistics, serial correlation, and cross-correlation are used as a preliminary statistics in the Korean Treasury Bond spot and futures market. Next, following Stoll-Whaley(1990) and Chan(1992), the multiple regression method is used to examine the lead-lag patterns between the two markets. The empirical results are summarized as follows. The mean returns of spot markets and future markets are positive(+) and negative(-) respectively and the standard deviation of both stock and futures returns increase through the sub-periods. For the most periods, there is negative skewness in the both markets. The zero excess kurtosis due to the heavy tails of the distribution are relatively large. The autocorrelations in the spot returns for the sample periods are positive in time lag 1, but the autocorrelations in the future returns shows no significant evidence. The results of the daily cross-correlations between the KTB spot and futures returns indicate that a lead-lag relationship don't exist for price changes of futures and spot markets as a preliminary analysis. Finally, empirical results of regression analysis for both market indicate that there is no evidence that the KTB futures lead the KTB spot market, or the KTB spot market lead the KTB futures market. These results are robust for all sub-periods.

• The Korean Journal of Ecology
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• v.23 no.3
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• pp.281-291
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• 2000

The objectives of this study were to classify quantitatively vegetational types of P. densiflora for. erecta forest. The results were summarized as follows. 1) According to the canonical correspondence analysis(CCA), variables such as topography, altitude, available P/sub 2/O/sub 5/, and Mg/sup 2＋/were highly correlated on three axes. Based on the correlations between vegetation units and environmental factors, Rhododendron micranthum community tended to be more distributed in the such situations of high altitude, upper topography, high C/N ratio, low level of Mg/sup 2＋/and Ca/sup 2＋/. Vaccinium koreanum community tended to be more distributed in the such conditions of high altitude, upper topography, high level of Ca/sup 2＋/and Ma/sup 2＋/. 2) According to the results of importance value analysis, Tree layer and Subtree layer in study areas showed high Ⅳ along with P. densiflora for. erecta, Quercus mongonlica, Q. variabilis, Q. serrata, Fraxinus rhychophylla and shrub layer indicated that Ⅳ of P. densiflora for, erecta in Sokwang-ri area was higher than those of the other areas. Therefore, it was considered that P. densiflora for. erecta forest of Sokwang-ri area could be naturally regenerated. 3) According to results of species diversity, the species diversity of Uljin region showed the least low value as 0.6622, other regions appeared about 0.7. In the diversity by vegetation types, Acer pseudosieboldianum community showed high value. 4) According to the analysis of community similarity, Sokwang-Ri region was lowly correlated with Uljin region, while the index among the other areas appeared above 0.6. 5) According to the analysis of interspecific association, it was divided into 2 groups. The species of first group were mainly involved in character species, and the species of second group were involved in differential species groups.

• Journal of Energy Engineering
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• v.8 no.2
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• pp.298-308
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• 1999

Experimental study on characteristics of direct contact condensation of steam discharged into a sub-cooled water pool has been performed using five different sizes of horizontal nozzle over a wide range of steam mass fluxes and pool temperatures. Steam condensation phenomena have been observed visually and by taking pictures of steam jets using a high speed video camera. Two different steam jet shapes such as ellipsoidal shape and conical shape were typically observed for a stable steam jet, depending on the steam mass flux and pool temperature. The steam jet expansion ratio and the steam jet length as well as the condensation heat transfer coefficients were determined. The effect of steam mass flux, pool temperature, and nozzle diameter on these parameters were also discussed. Empirical correlations for the steam jet lengths and the condensation heat transfer coefficients as a function of steam mass flux and condensation driving potential were established. The axial and radial temperature distributions in steam jet and in surrounding water were measured. The effect of steam mass flux, pool temperature, and nozzle diameter were also discussed. The condensation regime map, which consists of six regimes such as chugging, transient chugging, condensation oscillation, stable condensation, bubble condensation oscillation, and intermittent oscillation condensation, were established. In addition, the dynamic pressures at the pool wall were measured. The close relation of dynamic pressure and steam condensation mode, which is also dependent on steam mass flux and pool temperature, was found.

• Toxicological Research
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• v.25 no.2
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• pp.71-78
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• 2009

We investigated the pathogenesis of liver tissue damage during the lipid peroxidation and fibrogenesis with the observation of correlations between the parameters of collagen synthesis (and deposition) and lipid peroxidation in liver fibrosis (cirrhosis) rats. Rats were randomly divided into two groups, normal and $CCl_4$-thiopental sod. intoxicated group. And the one group was treated intragastrically with the mixture of $CCl_4$-thiopental sod. 3 times per week for 3 weeks. The liver tissue and sera were used for the measurement of hydroxyproline (HYP), malonedialdehyde (MDA) and superoxide dismutase (SOD). Biochemical parameters such as aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), total-bilirubin and blood urea nitrogen (BUN) were measured. Additionally, the expression of collagen ${\alpha}1$(III) and $\beta$-actin mRNA was observed by RTPCR. The histological change in liver tissue was also observed by Masson's trichrome and H&E staining. Correlation analysis was carried by Spearman's rho method. All biochemical parameters except total-bilirubin were significantly higher in the $CCl_4$-thiopental sod. treated group than that of the normal group (p < 0.01). In the $CCl_4$-thiopental sod. treated group, Hyp as a parameter of collagen synthesis (deposition) and MDA as a metabolite of lipid peroxidation, were significantly elevated by 1.98 and 2.11 times higher than that of the normal group (p < 0.001) respectively. The activity of SOD in the $CCl_4$-thiopental sod. treated group is decreased significantly by 44.8% (p < 0.001). And collagen ${\alpha}1$(III) mRNA was more expressed in the $CCl_4$-thiopental sod. treated group than that of the normal group. However, the expression of $\beta$-actin mRNA is showed similar in both of groups. A good correlation was observed between the content of hyp and MDA concentration (r = 0.70, n = 40) in the two groups. And the correlation between the levels of hyp and SOD (r = -0.71, n = 25) is also reliable. However, no correlation were observed between MDA concentration and SOD (r = -0.40, n = 25) in the two groups. Elevated levels of MDA in $CCl_4$-thiopental sod. treated rats indicated enhancement of lipid peroxidation, which is accompanied by a decrease in SOD activity. Moreover, we could confirm that the parameters of collagen synthesis (and deposition) is in good correlation with the metabolite of lipid peroxidation (MDA) and the lipid peroxidation antagonizing enzyme (SOD). Hence, we propose that (1) lipid peroxidation and collagen synthesis (and deposition) could be enhanced by intragastrically application of $CCl_4$-thiopental sod. during a short terms. And (2) the intoxication of $CCl_4$-thiopental sod. could be used for monitoring of lipid peroxidation and collagen synthesis (and deposition) for test of antioxidant and antifibrotic agent.

• Journal of Korean Society on Water Environment
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• v.32 no.3
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• pp.271-280
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• 2016

The aim of this study was to analyze spatial and temporal patterns of bacterial pollution levels and the relationship between bacterial pollutants and environmental parameters at the main stream and tributaries of Nakdong River. Water quality data including total coliform and fecal coliform were compiled from a total of 50 monitoring sites (30 at the main stream and 20 at the tributaries) along with rainfall and discharge data for three consecutive years from 2012 to 2014. During the study periods, the geometric mean values of total coliforms and fecal coliforms in the main stream were 74 (22~465) CFU/100 mL and 8 (3~42) CFU/100 mL, respectively. The geometric mean values of total coliforms and fecal coliforms in the tributaries were 275 (36~5,145) CFU/100 mL and 6 (1~1,352) CFU/100 mL, respectively. High concentrations of fecal coliforms were observed at Gumi (M 10), Hyeonpung (M 19), Hapcheon (M 23), and Namji (M 25) in the main stream, whereas Gamcheon (T 6), Bakcheon (T 7), Geumho-gang (T 8), and Gyeseongcheon (T 16) were identified as pollution hot spots in the tributaries. Although bacterial pollution levels showed complex behavior across monitoring sites and time, the highest coliform concentrations were routinely observed in the monsoon season between July and September of each year, indicating that the pollution levels were strongly dependent on precipitation in addition to other physiochemical parameters. Statistically significant correlations were found between fecal coliform concentrations and precipitation (r=0.403, p<0.01), followed by SS (r=0.425, p<0.01), nutrient TP (r=0.388, p<0.01), organic matter COD (r=0.322, p<0.01), and PO₄-P (r=0.317, p<0.01) in the main stream in the order of correlation coefficient from high to low.

• Korean Journal of Childcare and Education
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• v.10 no.5
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• pp.175-190
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• 2014

The purpose of this study was to examine the relationship among child care teachers' role performance and burnout, and supervisors' support. The subjects in this study were 171 child care teachers working in Gyeonggi province. Role performance questionnaire, the perceived supervisor's support scale, and the perceived burnout scale were used for this study. For the research analysis, frequency, Cronbach's ${\alpha}$ coefficient, and Pearson's correlation were calculated and regression analysis were conducted. The results are as follows. Firstly, it was revealed that both child care teachers' role performance and the perceived supervisors' support had statistically negative significant correlations with child care teachers' burnout. Secondly, role performance had statistically meaningful negative influences on child care teachers' overall burnout. Training and teaching activities as a sub-variable of child care teachers' role performance had statistically meaningful negative influences on emotional exhaustion, a lack of feeling of personal accomplishment, and overall job burnout. Thirdly, supervisors' support also had statistically meaningful negative influences on burnout. Material support as the sub-variable had statistically meaningful negative influences on emotional exhaustion, dehumanization, a lack of feeling of personal accomplishment, and overall job burnout. Evaluative support had statistically meaningful and negative influences on dehumanization and a lack of feeling of personal accomplishment. Through the results of this study, it must be indicated that it needs to promote the support of the supervisor in the various aspects and to provide a way which child care teachers efficiently perform the role in order to reduce their burnout.

• Journal of Korean Academy of Nursing
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• v.22 no.4
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• pp.620-635
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• 1992

This study identified correlations between perceived family support and hopelessness in patients admitted to Neuro - surgical Intensive Care Units. The purpose was to enhance theoretical understanding of the relationships of these two variables. The subjects of this study were 51 patients admitted to N-lCU, at three general hospitals in Seoul. Data were collected by researcher in structured interviews from Aug. 12 to Oct. 13, 1992. The research tools were parts of the Moos Family Environment Scale and the Beck Hopelessness Scale. The general characteristic data were analyzed for frequency and percentage ; the hypothesis was tested by the pearson product Moment Correlation Coefficient. After normality tests by using Kolmogorov - Sminorvtest, and T- test, ANOVA and Mann-Whitney U test, Kruskal -Wallis test were used on the Family Support and the Hopelessness about general charcteristics. The results of the above analysis were as follows 1) The average family support score for the group was 63.61 (tool average 51) and item average was 3.74 (tool item average 3) : the family support score of this sample was higher than average. The average family cohesion score of family support was 35.25 (tool average 27) and item average was 3.91 (tool item average 3). The average family expression score of family support was 28.35 (tool average 24) and item average was 3.57 (tool average 3). In this sample, perceived family expression was lower than family cohesion. 2) The average hopelessness score was 45.88 (tool average 60) and item average was 2.29 (tool item average 3) : the hopelessness score of this sample was low in comparison to the average. 3) The hypothesis in this study was supported. The main hypothesis that the higher the perceived family support level, the lower the level Of the hopelessness, was Supported (r＝-.3869 p＝.003). The sub-hypothesis that the higher the perceived family cohesion level, the lower the level of hopelessness, was supported(r＝-.3688 p＝.004). The sub-hypothesis that the higher the perceived family expression level, the lower the level of hopelessness, was supported (r＝-.3068 p＝.014). 4) General characteristics of the objects related to family support were ‘economic status’(p＝.025) and ‘helping person’(P＝.044) : the higher the economic status, the greater the family support. When the patient identified the helping person as a spouse, family support was rated more highly. The only general characteristic related to family cohesion was ‘helping person’(p＝.041). No general characteristics were related to family expression. 5) The one general characteristic related to hopelessness was ‘education’(p＝.002) : the higher their education, the lower their hopelessness. For these ICU patients, were related perceived family support and hopelessness, and family expression level was low in comparison to family cohesion level. The perceived family support of these seriously ill patients in situational crisis may have influenced the patient's emotional reaction of hopelessness. This study concluded that nurses in the ICU confirm the family support of the patient, and involve the family as the most intimate support systems in the care of the patient to help reduce the patient's hopelessness.

• Journal of the Korea Convergence Society
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• v.9 no.6
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• pp.77-88
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• 2018

"Standard Precautions" (SP) is important for nursing students as it will lead to the protection of health professionals from infectious diseases and prevention of the wide spread of epidemic illnesses. Therefore, this study investigated factors influencing nursing students' attitudes toward SP. Data were collected from 291 nursing students from May to June, in 2016. According to the results, perceived benefit (4.26) was the highest among sub factors of the health belief model, test score of SP was 78.8%, and attitude score (4 point scale) was 3.63. Perceived sensitivity, perceived benefits, perceived barriers, self-efficacy, knowledge about SP showed significant correlations with the attitudes towards SP. Among sub-factors of the health beliefs, perceived sensitivity (${\beta}=.152$, p<.05) and perceived barrier (${\beta}=-.125$, p<.05) were found to influence nursing students' attitudes toward SP (F= 5.680, p<.001). Hence, it can be concluded that a convergence education program promoting health belief is needed for improving attitudes toward SP among nursing students.

• Culinary science and hospitality research
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• v.19 no.4
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• pp.176-192
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• 2013

This study examined how empowerment of restaurant cooks influences job satisfaction, organizational commitment, and customer orientation, targeting 260 restaurant cooks in the Busan area. SPSS 18.0 was employed to perform frequency, factor, reliability, and multiple (simple) regression analyses. Empowerment was analyzed using 3 factors (self-authority, meaning and competence) while job satisfaction, organizational commitment, and customer orientation were analyzed using 1 factor each. Results of a correlation analysis of the hypothesized model revealed positive correlations among the variables. Multiple (simple) regression analyses of the hypothesized model found that the sub empowerment factors will have a positive influence on job satisfaction with self-authority (${\beta}$=.372, p<.001), meaning (${\beta}$=.451, p<.001), competence (${\beta}$=.240, p<.001). It was also found that the sub empowerment factors will have a positive influence on organizational commitment with self-authority (${\beta}$=.433, p<.001), meaning (${\beta}$=.473, p<.001), competence (${\beta}$=.302, p<.001). Lastly, the hypotheses that job satisfaction will have a positive influence on organizational commitment (${\beta}$=.775, p<.001), that job satisfaction will have a positive influence on customer orientation (${\beta}$=.467, p<.001), and that organizational commitment will have a positive influence on customer orientation (${\beta}$=.567, p<.001) were adopted.

• The Journal of Advanced Prosthodontics
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• v.10 no.2
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• pp.113-121
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• 2018

PURPOSE. The aim of this preliminary study was to investigate, for the first time, the effects of addition of titania nanotubes ($n-TiO_2$) to poly methyl methacrylate (PMMA) on mechanical properties of PMMA denture base. MATERIALS AND METHODS. $TiO_2$ nanotubes were prepared using alkaline hydrothermal process. Obtained nanotubes were assessed using FESEM-EDX, XRD, and FT-IR. For 3 experiments of this study (fracture toughness, three-point bending flexural strength, and Vickers microhardness), 135 specimens were prepared according to ISO 20795-1:2013 (n of each experiment=45). For each experiment, PMMA was mixed with 0% (control), 2.5 wt%, and 5 wt% nanotubes. From each $TiO_2$:PMMA ratio, 15 specimens were fabricated for each experiment. Effects of $n-TiO_2$ addition on 3 mechanical properties were assessed using Pearson, ANOVA, and Tukey tests. RESULTS. SEM images of $n-TiO_2$ exhibited the presence of elongated tubular structures. The XRD pattern of synthesized $n-TiO_2$ represented the anatase crystal phase of $TiO_2$. Moderate to very strong significant positive correlations were observed between the concentration of $n-TiO_2$ and each of the 3 physicomechanical properties of PMMA (Pearson's P value ${\leq}.001$, correlation coefficient ranging between 0.5 and 0.9). Flexural strength and hardness values of specimens modified with both 2.5 and 5 wt% $n-TiO_2$ were significantly higher than those of control ($P{\leq}.001$). Fracture toughness of samples reinforced with 5 wt% $n-TiO_2$ (but not those of 2.5% $n-TiO_2$) was higher than control (P=.002). CONCLUSION. Titania nanotubes were successfully introduced for the first time as a means of enhancing the hardness, flexural strength, and fracture toughness of denture base PMMA.