• International Journal of Computer Science & Network Security
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• v.21 no.4
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• pp.52-58
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• 2021

Questionnaires and surveys are increasingly being used to collect information from participants of empirical software engineering studies. Usually, such data is analyzed using statistical methods to show an overall picture of participants' agreement or disagreement. In general, the whole survey population is considered as one group with some methods to extract varieties. Sometimes, there are different opinions in the same group, but they are not well discovered. In some cases of the analysis, the population may be divided into subgroups according to some data. The opinions of different segments of the population may be the same. Even though the existing approach can capture the general trends, there is a risk that the opinions of different sub-groups are lost. The problem becomes more complex in longitudinal studies where minority opinions might fade over time. Longitudinal survey data may include several interesting patterns that can be extracted using a clustering process. It can discover new information and give attention to different opinions. We suggest using a data mining approach to finding the diversity among the different groups in longitudinal studies. Our study shows that diversity can be revealed and tracked over time using the clustering approach, and the minorities have an opportunity to be heard.

• Journal of Preventive Medicine and Public Health
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• v.43 no.2
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• pp.174-184
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• 2010

Objectives: This study shows the issues that should be considered when applying standardized rates using Community Health Survey(CHS) data. Methods: We analyzed 2008 CHS data. In order to obtain the reliability of standardized rates, we calculated z-score and rank correlation coefficients between direct standardized rate and indirect standardized rate for 31 major indices. Especially, we assessed the change of correlations according to population composition (age and sex), and characteristics of the index. We used Mantel-Haenszel chi-square to quantify the difference of population composition. Results: Among 31 major indices, 29 indices' z-score and rank correlation coefficients were over 0.9. However, regions with larger differences in population composition showed lower reliability. Low reliability was also observed for the indices specific to subgroups with small denominator such as 'permanent lesion from stroke', and the index with large regional variations in age-related differences such as 'obtaining health examinations'. Conclusions: Standardized rates may have low reliability, if comparison is made between areas with extremely large differences in population composition, or for indicies with large regional variations in age-related differences. Therefore, the special features of standardized rates should be considered when health state are compared among areas.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.1
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• pp.1-7
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• 2018

Information on the patterns of genetic diversity and population structure is essential for the rational use and efficient management of germplasms; accurate information aids in monitoring germplasms, and can also be used to predict potential genetic gains. In this study, we assessed genetic diversity, focusing on Korean rice accessions for theand their sustainable conserved diversity. Using DNA profiling with 12 simple sequence repeat (SSR) markers, we detected a total of 333 alleles among 2,016 accessions. The number of alleles ranged from 21 to 53, with an average of 27.8. Average polymorphism information content was 0.797, with the lowest being 0.667 and the highest 0.940. CA cluster analysis and the model-based population structure revealed two main groups that could be subdivided into five subgroups. Analysis of the molecular variance study based on the SSR profile data showed 5% variance among the profiles, whereas we recorded 93% variance among individuals and 2% variance within individuals. Specifically, the utilized diversity for of the breeding program is restricted in that cultivars were located in limited clades. These results revealed that preserving the diversity of Korean landraces could be useful sources for breeding new rice cultivars, and cwould be the basis for the sustainable conservation and utilization of a Korean rice germplasm.

• Journal of Korean Neurosurgical Society
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• v.66 no.1
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• pp.95-104
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• 2023

Objective : Hypernatremia is a common complication encountered during the treatment of neurocritically ill patients. However, it is unclear whether clinical outcomes correlate with the severity of hypernatremia in such patients. Therefore, we investigated the impact of hypernatremia on mortality of these patients, depending on the degree of hypernatremia. Methods : Among neurosurgical patients admitted to the intensive care unit (ICU) in a tertiary hospital from January 2013 to December 2019, patients who were hospitalized in the ICU for more than 5 days and whose serum sodium levels were obtained during ICU admission were included. Hypernatremia was defined as the highest serum sodium level exceeding 150 mEq/L observed. We classified the patients into four subgroups according to the severity of hypernatremia and performed propensity score matching analysis. Results : Among 1146 patients, 353 patients (30.8%) showed hypernatremia. Based on propensity score matching, 290 pairs were included in the analysis. The hypernatremia group had higher rates of in-hospital mortality and 28-day mortality in both overall and matched population (both p<0.001 and p=0.001, respectively). In multivariable analysis of propensity score-matched population, moderate and severe hypernatremia were significantly associated with in-hospital mortality (adjusted odds ratio [OR], 4.58; 95% confidence interval [CI], 2.15-9.75 and adjusted OR, 6.93; 95% CI, 3.46-13.90, respectively) and 28-day mortality (adjusted OR, 3.51; 95% CI, 1.54-7.98 and adjusted OR, 10.60; 95% CI, 5.10-21.90, respectively) compared with the absence of hypernatremia. However, clinical outcomes, including in-hospital mortality and 28-day mortality, were not significantly different between the group without hypernatremia and the group with mild hypernatremia (p=0.720 and p=0.690, respectively). The mortality rates of patients with moderate and severe hypernatremia were significantly higher in both overall and matched population. Interestingly, the mild hypernatremia group of matched population showed the best survival rate. Conclusion : Moderate and severe hypernatremia were associated with poor clinical outcomes in neurocritically ill patients. However, the prognosis of patients with mild hypernatremia was similar with that of patients without hypernatremia. Therefore, mild hypernatremia may be allowed during treatment of intracranial hypertension using hyperosmolar therapy.

• Journal of Preventive Medicine and Public Health
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• v.53 no.5
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• pp.332-341
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• 2020

Objectives: The purpose of this study was to investigate the association between the Basic Old-Age Pension (BOP), which is a non-contributory pension, and depression in BOP beneficiaries in Korea. Methods: We used the second and third waves (2007-2008) of the Korea Welfare Panel Study to identify the effect of the BOP on mental health in the year of its introduction. The Center for Epidemiological Studies-Depression Scale, applied in a Korean context, was used to evaluate mental health. To analyze the effect of the BOP, a difference-in-difference approach was used in analyses of all subjects and subgroups. Results: For this study population of 760 adults, the BOP did not have a statistically significant relationship with depression in its beneficiaries. After controlling for type of household, the BOP was still not associated with lower reporting of depression, either in single-beneficiary or double-beneficiary households, in the year of the benefit. Conclusions: The BOP policy had no significant relationship with the level of depression among recipients. However, this should not be interpreted as implying that income subsidy programs for older adults, such as the BOP, do not affect mental health, considering the importance of economic hardship in this population and the program's socioeconomic effects.

• Journal of the Korean Society of Food Culture
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• v.35 no.6
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• pp.553-568
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• 2020

This systematic review and meta-analysis aimed to determine whether food intake is effective in preventing diseases related to cognitive impairment. We searched English databases namely MEDLINE, PubMed and ScienceDirect from 2000 to May 2020, and Korean databases namely RISS, KISS, and DBPIA from 1990 to May 2020. We divided the data into 15 groups using the food group classification of the Korean Nutrition Society (KNS). The effect size (Cohen's d) was estimated using a random-effect model, and a 95% confidence interval was calculated for each study. We included 17 cross-sectional studies and 7 cohort studies which involved 45,115 participants. As a result of analyzing the subgroups in the Asian population of both sexes, it was observed that grain intake has a protective effect against cognitive impairment. For females, pulses and fish also have a protective role against cognitive impairment. In the case of seaweed, a negative relationship was found with a moderate protective effect against cognitive impairment (Cohen's d:-0.533, 95% CI: -0.939, -0.126; p=0.010) in Korean studies. Dairy products are associated with an increased risk of cognitive impairment in the American and European population but drinking alcohol is associated with a lower impairment risk. These results provide a basis for formulating the dietary guidelines for preventing dementia for each country.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.7
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• pp.225-234
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• 2021

This research aimed to investigate the key factors affecting student satisfaction and loyalty in selected private universities in Cambodia. The study implemented a quantitative survey designed and guided by seven hypotheses to test the causal relationships among variables, such as academic experience, faculty services, campus life, social integration, student support facilities, student satisfaction, university image, and student loyalty. The research applied a multi-stage sampling technique of probability procedures to guarantee the presence of the research population. Confirmatory Factor Analysis (CFA) and Structural Equation Modeling (SEM) were applied for data analysis to test the hypotheses model. The collected survey totaled 543 from three universities. The purposive sampling methods were used to select the three target universities, based on their reputation, the number of students, year of establishment, and the recognition from the Ministry of Education, Youth, and Sport. The stratified random sampling method was employed to select target respondents for data collection by dividing the population into subgroups to ensure a random sample. The results showed that student support facilities, campus life, and social integration, faculty services, and university image play very important roles in the satisfaction and loyalty of the students in three universities.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.220-220
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• 2022

Disproportionating Enzyme 1 (DPE1) is an a-1,4-D-glucanotransferase that cleavages the a-1,4-glucosidic bonds and transfers glucosyl groups. In rice endosperm, it participates in starch synthesis by transferring maltooligosyl groups from amylose and amylopectin to amylopectin. Here, we investigated the haplotype variations and evolutionary indices (e.g., genetic diversity and population structure) for the DPE1 gene in 374 rice accessions representing seven subgroups (wild, indica, temperate japonica, tropical japonica, aus, aromatic, and admixture). Variant calling analysis of DPE1 coding regions leads to the identification of six functional haplotypes representing/occupying 8 nonsynonymous SNPs. Nucleotide diversity analysis revealed the highest pi-value in wild group (0.0556) compared to other cultivated groups, of which temperate japonica showed the most reduction of genetic diversity value (0.003). A significant positive Tajima's D value (1.6330) of admixture highlights sudden population contraction under balancing selection, while temperate japonica with the lowest Tajima's D value (-1.3523) showed a selection signature of DPE1 domestication which might be the cause of excess of rare alleles. Moreover, these two subpopulations exhibits a greater differentiation (F_ST=0.0148), indicating a higher genetic diversity. Our findings on functional DPE1 haplotypes will be useful in future breeding programs, and the evolutionary indices can also be applicable in functional studies of the DPE1 gene.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.215-215
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• 2022

Starch synthase proteins (SSI, SSII and SSIII) in rice are mainly involved in amylopectin synthesis mediating its chain elongation, and the functional loss of SSII can increase amylose accumulation through decreasing of amylopectin chain proportions. For purposes of identifying functional haplotypes and evolutionary analyses of this gene, SSII-1, we investigated 374 rice accessions belonging to different subgroups of origins. We subsequently performed bioinformatic analyses on their variations through haplotyping, resequencing and structuring based on different classified populations. Haplotyping of cultivated rice accessions using genetic variations within SSII-1 genomic region of chromosome 10 revealed a total of 8 haplotypes, representing 6 functional haplotypes by 4 non-synonymous SNPs of three different exons (1, 4 and 10), which effect on protein structure. Higher nucleotide diversity value was found in wild group (0.0055) compared to any of cultivated subpopulations, of which aus showed the most reduction of diversity value (0.0003). Tajima's D analysis exhibits the most Tajima's D value only in admixture group (0.3600) which appears to be the cause of a sudden population contraction by rare alleles scarcity. A clear separation of some wild accessions from the admixed cultivated subpopulations was observed in PCA and phylogenetic analysis. Similar admixed pattern of population structure was estimated with an increased K values of 2 to 8 where genetic components of almost all cultivated subpopulations were shared with the wild which can also be subsequently estimated by very low F_ST-values by -0.011 (wild-aromatic) and -0.003 (wild-admixture).

• Journal of the Korean Society of Food Culture
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• v.31 no.2
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• pp.121-130
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• 2016

This study attempted to understand the fast food brand personality in the domestic dining market to present the repositioning strategies within the competitive market. Positive analysis results were as follows. First, the five brand individualities of 'familiarity', 'passion', 'professionalism', 'reliability', and 'refinement' were derived. Second, the deductions made on perceptions of the population using a Biplot based on the brand personality showed that there were significant differences among the brand personality images of the brands, which were the targets of comparison. Third, there were significant between-group differences in the comparisons of perception among the subgroups according to gender, brand reliability, and brand satisfaction. Fourth, there were significant between-group differences in the consumer fast food brand preferences and ideal point. Such studies can provide information useful for establishing marketing differentiating strategies by grasping the brand personality of competing brands in the market.