• Journal of Preventive Medicine and Public Health
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• v.52 no.6
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• pp.355-365
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• 2019

Objectives: In rural areas of Korea, where public transportation infrastructure is lacking and alternative systems are poor, the elderly experience inconveniences in using healthcare, although their need is high. This study aimed to analyze the association between the convenience of transportation and unmet healthcare needs among the rural elderly. Methods: The data used were collected in the 2016 Community Health Survey among rural elderly individuals aged 65 or older. Dependent variable was the unmet healthcare needs, explanatory variable was the convenience of transportation. The elderly were divided into 3 groups: with no driver in the household, with a driver, and the elderly individual was the driver (the self-driving group). Covariates were classified into predisposing, enabling, and need factors. They included gender, age, education, income, economic activity, household type, motor ability, subjective health level, number of chronic diseases, anxiety/depression, and pain/discomfort. The data were analyzed using logistic regression and stratification. Results: A significant association was found between the convenience of transportation and unmet healthcare needs. When examined unadjusted odds ratio of the group with a driver in the household, using the group with no driver as a reference, was 0.61 (95% confidence interval [CI], 0.54 to 0.68), while that of the self-driving group was 0.34 (95% CI, 0.30 to 0.38). The odds ratios adjusted for all factors were 0.69 (95% CI, 0.59 to 0.80) and 0.79 (95% CI, 0.67 to 0.91). Conclusions: We confirmed a significant association between inconvenient transportation and unmet healthcare needs among the rural elderly even after adjustment for existing known factors. This implies that policies aimed at improving healthcare accessibility must consider the means of transportation available.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.9
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• pp.361-366
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• 2016

As an alternative of well-mixed storage tank with lower coil only, we have proposed a tank with lower and upper coils and verified a superior thermal stratification in a tank, which results in increased collector efficiency and solar fraction. But the phenomenon of temperature reversal was often experimentally observed in the tank, so a revised control was successfully applied which is to heat only lower coil using three way valve if temperature reversal occurs and to operate the collector with low flow rate when the condition of solar radiation is not good. In the present study, using TRNSYS we compared the existing lower heating and the proposed lower and upper heating with a control preventing temperature reversal. The results showed that the proposed method has an increase of collector efficiency by 5.1% and solar fraction by 3.2%.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.5
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• pp.507-518
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• 2022

This study aimed to measure the monetary and non-monetary effects on brand awareness at hypermarkets in Riyadh. The independent variable consists of three sub-variables: price reductions, free samples, and purchasing vouchers. The research population has all Saudi and non-Saudi buyers in Riyadh. The figures show that the population size reached 3.87 million in 2019. The proportional stratification sampling technique and the recommended sample size were 387 buyers. The five-point Likert scale with the fully structured questionnaire was used. The study concldes the effect of free samples on brand awareness while there was no effect of monetary instruments. The results show that the three sales promotion incentives (price reduction, free samples, and purchasing vouchers) moderately affected brand awareness and a key role in explaining consumer behavior, so the significant impact was proved. In summary, this study showed that price reductions have the power of creating the perception of buyers at hypermarkets in Riyadh. Non-cash instruments were more effective than cash instruments in enhancing brand awareness at the hypermarkets in the Saudi market. So, the price reductions and purchasing vouchers have less power in conducting communication-based awareness. Building awareness and improving brand image through free samples were most visible in communication strategy.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.1
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• pp.65-74
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• 2020

The purpose of this study was to investigate the physical characteristics of marine environment, and to predict the probability of the occurrence of hypoxia in the Dangdong bay. We predicted hypoxia using the logistic regression model analysis by observing the water temperature, salinity, and dissolved oxygen concentration. The analysis showed that the Brunt-Väisälä frequency which was shallow than the deep bay entrance, was higher inside the bay due to a lesser amount of fresh water inflow from the inner side of the bay, and density stratification was formed. The Richardson number, and Brunt-Väisälä frequency were very high occasionally from June to September; however, after September 2, the stratification had a tendency to decrease. Analysis of dissolved oxygen, water temperature, and salinity data observed in Dangdong bay showed that the dissolved oxygen concentration in the bottom layer was mostly affected by the temperature difference (dt) between the surface layer and bottom layer. Meanwhile, when the depth difference (dz) was set as a fixed variable, the probability of the occurrence of hypoxia varied with respect to the difference in water temperature. The depth difference (dz) was calculated to be 5 m, 10 m, 15 m, 20 m, and the difference in water temperature (dt) was found to be greater than 70 % at 8℃, 7℃, 5℃, and 3℃. This indicated that the larger the difference in depth in the bay, the smaller is the temperature difference required for the generation of hypoxia. In particular, the place in the bay, where the water depth dif erence was approximately 20 m, was found to generate hypoxia.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.19
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• pp.8351-8359
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• 2014

Background: Recent epidemiological data have implicated human papilloma virus (HPV) infection in the pathogenesis of head and neck cancers, especially oropharyngeal cancers. Although, HPV has been detected in varied amounts in persons with oral dysplasia, leukoplakias and malignancies, its involvement in oral tongue carcinogenesis remains ambiguous. Materials and Methods: HPV DNA prevalence was assessed by PCR with formalin fixed paraffin embedded sections (n=167) of oral tongue squamous cell carcinoma patients and the physical status of the HPV16 DNA was assessed by qPCR. Immunohistochemistry was conducted for p16 evaluation. Results: We found the HPV prevalence in tongue cancers to be 51.2%, HPV 16 being present in 85.2% of the positive cases. A notable finding was a very poor concordance between HPV 16 DNA and p16 IHC findings (kappa<0.2). Further molecular classification of patients based on HPV16 DNA prevalence and p16 overexpression showed that patients with tumours showing p16 overexpression had increased hazard of death (HR=2.395; p=0.005) and disease recurrence (HR=2.581; p=0.002) irrespective of their HPV 16 DNA status. Conclusions: Our study has brought out several key facets which can potentially redefine our understanding of tongue cancer tumorigenesis. It has emphatically shown p16 overexpression to be a single important prognostic variable in defining a high risk group and depicting a poorer prognosis, thus highlighting the need for its routine assessment in tongue cancers. Another significant finding was a very poor concordance between p16 expression and HPV infection suggesting that p16 expression should possibly not be used as a surrogate marker for HPV infection in tongue cancers. Interestingly, the prognostic significance of p16 overexpression is different from that reported in oropharyngeal cancers. The mechanism of HPV independent p16 over expression in oral tongue cancers is possibly a distinct entity and needs to be further studied.

• Survey Research
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• v.10 no.1
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• pp.155-168
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• 2009

As an efficient sampling design, stratified random sampling is often used when auxiliary information is available at the designing stage. Although one - per - stratum design is an efficient design that can be used when many auxiliary variables are available, it does not provide any unbiased variance estimator. With a two - per - stratum sample in which two elements are selected from each stratum, it is possible to obtain an unbiased variance estimator. However the loss of efficiency could be significant if any important stratification variable is missed. In this study, we investigated a sampling design that uses the all given auxiliary information and also permits an unbiased variance estimator suggested by Park and Fuller(2008). Through a simulation study, we compared several stratified random sampling and systematic sampling design. We also applied the proposed stratified sampling designs to 2007 youth panel data.

• Journal of the Korean Home Economics Association
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• v.40 no.9
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• pp.127-141
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• 2002

This research aims to examine the influence of facilitative communication between mother and high school daughter on daughter's perceived family cohesion, family adaptability, and satisfaction of mother's working or non-working status. In order to verify statistically the research questions above, experimental tools were made for each variable, and Cluster Sampling with Stratification was conducted among high school girls in Seoul. A total of 670 questionnaire sheets were administered to 13 high schools for girls in December 2001, and only 501 sheets were used for data analysis. The SPSS 10.0 package was used for factor analysis, reliability analysis, multiple regression analysis. The following results were obtained: 1) Mother-high school daughter's facilitative communication significantly influences daughter's perceived family cohesion. In general, mother-high school daughter's facilitative communication had R square of 27.6% with regards to daughter's perceived family cohesion. 2) Mother-high school daughter's facilitative communication significantly influences daughter's perceived family adaptability. In general, mother-high school daughter's facilitative communication had R square of 25.3% with regards to daughter's perceived family adaptability. 3) Mother-high school daughter's facilitative communication significantly influences daughter's perceived satisfaction of mother's working of non-working status. In general, mother-high school daughter's facilitative communication had R square of 24.0% with regards to daughter's perceived satisfaction of mother's working status, and 7.4% with regards to non-working status.

• Korean Journal of Radiology
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• v.22 no.9
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• pp.1481-1489
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• 2021

Objective: To construct a CT-based Fagotti scoring system by analyzing the correlations between laparoscopic findings and CT features in patients with advanced ovarian cancer. Materials and Methods: This retrospective cohort study included patients diagnosed with stage III/IV ovarian cancer who underwent diagnostic laparoscopy and debulking surgery between January 2010 and June 2018. Two radiologists independently reviewed preoperative CT scans and assessed ten CT features known as predictors of suboptimal cytoreduction. Correlation analysis between ten CT features and seven laparoscopic parameters based on the Fagotti scoring system was performed using Spearman's correlation. Variable selection and model construction were performed by logistic regression with the least absolute shrinkage and selection operator method using a predictive index value (PIV) ≥ 8 as an indicator of suboptimal cytoreduction. The final CT-based scoring system was internally validated using 5-fold cross-validation. Results: A total of 157 patients (median age, 56 years; range, 27-79 years) were evaluated. Among 120 (76.4%) patients with a PIV ≥ 8, 105 patients received neoadjuvant chemotherapy followed by interval debulking surgery, and the optimal cytoreduction rate was 90.5% (95 of 105). Among 37 (23.6%) patients with PIV < 8, 29 patients underwent primary debulking surgery, and the optimal cytoreduction rate was 93.1% (27 of 29). CT features showing significant correlations with PIV ≥ 8 were mesenteric involvement, gastro-transverse mesocolon-splenic space involvement, diaphragmatic involvement, and para-aortic lymphadenopathy. The area under the receiver operating curve of the final model for prediction of PIV ≥ 8 was 0.72 (95% confidence interval: 0.62-0.82). Conclusion: Central tumor burden and upper abdominal spread features on preoperative CT were identified as distinct predictive factors for high PIV on diagnostic laparoscopy. The CT-based PIV prediction model might be useful for patient stratification before cytoreduction surgery for advanced ovarian cancer.

• Korean Journal of Ecology and Environment
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• v.35 no.2 s.98
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• pp.79-91
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• 2002

A time variable modeling study was performed for seasonal variations of vertical temperature profiles in the Okjung Lake located in upstream of the Sumjin River. Based on the model structure of the US Army Corps of Engineer's CE-QUAL-W2, the lake was divided into 3 branches, 50 longitudinal segments and 49 vertical layers and vertical profiles of water temperature and current velocity were simulated over one year. The model results were calibrated and verified against vertical profiles of water temperature measured every month from March 1998 to February 1999 at 5 different locations. The model results showed a good agreement with the field measurements. The hydrologic balance during this period was validated by comparing the simulated values of surface elevation level with the measured data. There was some discrepancy in July data between the model results and the fleld measurements. This could be attributed partially to the inadequacy of the model to the highly hydrodynamic nature of water body and partially to the lack of accuracy in local atmospheric temperature data during summer monsoon period. The model results have shown that there was no seasonal over-turn in most part of the Okjung Lake, where water temperature maintained above $4^{\circ}C$ over one year. In the upstream shal-low area (depth<20 meter), however, temperature at surface layer fell below $4^{\circ}C$ and water was frozen such that slight over-turn would occur during winter period. From this study, we concluded that the Okjung Lake is oligomictic. This conclusionis significantly different from the general pattern that the lakes located from $20^{\circ}C$ to $40^{\circ}C$ latitude would be warm monomictic. From the examination of simulated current velocity distribution, it was found that the upstream inflows would infiltrate into mesolimnion of the lake during hydrodynamic summer monsoon periods due to the thermal density of water.

• Korean Journal of Soil Science and Fertilizer
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• v.1 no.1
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• pp.129-136
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• 1968

Low-Humic Gley Soils occur very commonly in Korea and constitute important paddy soils of the country. These soils are developed either on alluvial or fluvio-marine materials. The soils in the present invest igation are derived from the latter. The interesting morphological features of these two soils are the presence of $FeCO_3$ concretions in the subsoil and the occurrence of a buried black organic horizon of variable thickness(25-100 cm). The organic horizon overlies the greenish marine material and underlies the continental material. These soils have poor drainage and are wet most of the year. The presence of $FeCO_3$ concretions in poorly drained paddy soils has previously been reported in North America(8), Japan(9) and West Europe(7). The purpose of this investigation is to study the chemical and mineralogical characteristics of these soils; and the genesis of $FeCO_3$ concretions. Profile samples of both these soils were collected from Gimjae area, in co-operation with the Soil Survey Party. These profiles were described as follows: