• Journal of the Korea Society for Simulation
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• v.22 no.3
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• pp.15-23
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• 2013

In general, simulation models are effectively used in the field of engineering design. The experiment with simulation models to obtain optimal design parameters, however, is a time-consuming task and requires a lot of resources. Hence, meta-models representing the relationships between input variables and performance measures are exploited to efficiently determine the value of design parameters. To construct a meta-model, a number of simulation executions with sample scenarios are required. The number and quality of sample scenarios determine not only the level of efficiency in constructing the meta-model but also accuracy of the model. Space-filling condition is regarded to be an important condition for the quality of scenarios. This paper proposes sample scenario generation methods based on space-filling measures such as maxmin, Audze-Eglais, and centered L2-discrepancy. The performance of these scenario generation methods are evaluated through experiments.

• Journal of the Korea Society of Computer and Information
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• v.24 no.1
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• pp.121-128
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• 2019

An Internet of Things(IoT) technology which provides intelligent services by combining context-awareness based intelligences, inter-communication is made of between things and things or between things and person through the network connected with intelligent things is spreading rapidly. Especially as this technology is converged into smart device, mobile, cloud, big data technologies, it is applied into various domains. Therefore, this is different from existing Web or Mobile Application. New types of IoT applications are emerging by adapting IoT into Web or mobile. Because IoT application is not only focused on software but also considering hardware or things aspect, there are limitations existing development process. Existing development processes don't consider analysis and design techniques considering both hardware and things. We propose not only a meta-model for development process which can support IoT application's development but also meta-models for main activities in this paper. Especially we define modeling elements by using UML's extension mechanisms, provide development process, and suggest design techniques how to apply those elements into IoT application's modeling phase. Because there are many types of IoT application's type, we propose an Android and Arduino-based on IoT application as a case study. We expect that proposed technique can be applied into many of various IoT application development and design with a form of flexible and extensible as well as main functionalities or elements are more concretely described. As a result, it brings IoT application's flexibility and the effect of quality improvement.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.6
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• pp.33-43
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• 2021

A60 class bulkhead penetration piece is a fire resistance system installed on a bulkhead compartment to protect lives and to prevent flame diffusion in a fire accident on a ship and offshore plant. This study focuses on the approximate optimization of the fire resistance design of the A60 class bulkhead penetration piece using a multi-island genetic algorithm. Transient heat transfer analysis was performed to evaluate the fire resistance design of the A60 class bulkhead penetration piece. For approximate optimization, the bulkhead penetration piece length, diameter, material type, and insulation density were considered discrete design variables; moreover, temperature, cost, and productivity were considered constraint functions. The approximate optimum design problem based on the meta-model was formulated by determining the discrete design variables by minimizing the weight of the A60 class bulkhead penetration piece subject to the constraint functions. The meta-models used for the approximate optimization were the Kriging model, response surface method, and radial basis function-based neural network. The results from the approximate optimization were compared to the actual results of the analysis to determine approximate accuracy. We conclude that the radial basis function-based neural network among the meta-models used in the approximate optimization generates the most accurate optimum design results for the fire resistance design of the A60 class bulkhead penetration piece.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5621-5626
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• 2014

N-acetyltransferase 2 (NAT2) is a polymorphic enzyme that plays an important role in the metabolism of various potential carcinogens. In recent years, a number of studies have been carried out to investigate the relationship between the rs1799930 and rs1799931 polymorphism in NAT2 and cancer risk in multiple populations for different types of cancer. However, the results were not consistent. Therefore, we performed a meta-analysis to further explore the relationship between NAT2 polymorphism and the risk of cancer. A total of 21 studies involving 15, 450 subjects for rs1799930 and 13, 011 subjects for rs1799931 were included in this meta-analysis. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess strength of associations. We also evaluated the publication bias and performed a sensitivity analysis. Overall, our results showed an apparent significant association between the NAT2 rs1799930 polymorphism and cancer susceptibility in Asians (GA vs. GG: OR=1.22, 95% CI=1.03-1.45; dominant model: OR=1.22, 95% CI=1.03-1.43) and population-based controls (GA vs. GG: OR=1.10, 95% CI=1.01-1.19; dominant model: OR=1.09, 95% CI=1.01-1.18). In contrast, a significant association was observed between the NAT2 rs1799931 G>A polymorphism and decreased cancer susceptibility in overall meta-analysis (AA vs. GG: OR=0.55, 95% CI=0.33-0.93; GA vs. GG: OR=1.00, 95% CI=0.88-1.14; dominant model: OR=0.97, 95% CI=0.86-1.10; recessive model: OR=0.56, 95% CI=0.34-0.94) and the Asian group (AA vs. GG: OR=0.50, 95% CI=0.26-0.94; recessive model, OR=0.50, 95% CI=0.27-0.94). We found that the NAT2 rs1799930 may be a risk factor, while the NAT2 rs1799931 polymorphism is associated with a decreased risk of cancer and is likely a protective factor against cancer development.

• The Korean Journal of Pain
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• v.30 no.4
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• pp.250-257
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• 2017

Vitamin D is a cofactor responsible for autoimmune disorders. There is no agreement in the studies investigating the association between vitamin D and fibromyalgia. This study aims to combine the conflicting results of the primary studies which compared these patients with control groups regarding the serum concentration of vitamin D. This meta-analysis has been designed based on PRISMA guidelines. Relevant keywords were searched in PubMed, Science direct, Scopus, Cochrane, and Google scholar and primary studies were selected. After screening the eligible studies according to inclusion/exclusion criteria, we investigated the risk of bias in the selected studies and also the heterogeneity between the primary results using Cochrane (Q) and I-squared ($I^2$) indices. The primary results were combined using inverse variance method and Cohen statistics as well as a random effects model. Publication bias was assessed using Egger test. Sensitivity analysis was applied to investigate the influence of each primary study on the final result of the meta-analysis. Suspected factors in the heterogeneity were assessed using meta-regression models. We entered 12 eligible studies in the meta-analysis including 851 cases compared with 862 controls. The standardized mean difference of Vitamin D between the two groups was -0.56 (95% confidence interval: -1.05, -0.08). Our meta-analysis showed that vitamin D serum levels of patients with fibromyalgia was significantly lower than that of control group.

• Journal of Nutrition and Health
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• v.36 no.5
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• pp.515-527
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• 2003

Objectives： A meta-analysis of the literatures was conducted to evaluate the cost-effectiveness of medical nutrition therapy by dietitians. Methods : The 30 studies were identified from a computerized search of published research on MEDLINE, Science-Direct and the PQD database until May, 2002 and a review of reference lists. The main search terms were“dietitian”,“dietary intervention”,“nutrition intervention”, “cost”,“cost-effectiveness”and“cost-benefit analysis”. The subgroup analysis was performed by publication year, study design, intervention provider, type of patient (in/out-patient) and type of cost (total cost/direct cost). Two reviewers independently selected trials for inclusion, assessed the quality and extracted the data. Results : The 30 studies were identified using the electric database search and bibliographies. The 17 trials were eligible for inclusion criteria, then the systematic review and a meta-analysis were conducted on effectiveness and cost-effectiveness of medical nutrition therapy. The quality of the studies was evaluated using the quality assessment tool for observational studies. The quality score was 0.515 $\pm$ 0.121 (range : 0.279-0.711, median : 0.466). The meta-analysis of 17 studies based on the random effect model showed that medical nutrition therapy was highly effective in treating the diseases (effect size 0.3092 : 95% confidence interval 0.2282-0.3303). The vote-counting method, one of meta-analysis methods, was applied to evaluate the cost-effectiveness of medical nutrition therapy conducted by dietitians. Two criteria (method 1, method 2) for voting were used. The calculated p-values for method 1 (more conservative method) and method 2 (less conservative method) were 0.1250 and 0.0106, respectively. Medical nutrition therapy by dietitians was significantly cost-effective in the method 2. Conclusion. This meta-analysis showed that the effectiveness of medical nutrition therapy was statistically significant in treating disease (effect size 0.3092), and that the cost-effectiveness of medical nutrition therapy was statistically significant in the method 2 (less conservative method) of vote counting. (Korean J Nutrition 36(5): 515~527, 2003)

• Communications for Statistical Applications and Methods
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• v.18 no.1
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• pp.57-69
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• 2011

Researchers are continuously trying to find innovative diagnostic tests and published articles are accumulating at an enormous rate in many medical fields. Meta-analysis enables previously published study results to be reviewed and summarized; therefore, an objective assessment of diagnostic tests can be done with a meta-analysis of sensitivities and specificities. Data obtained by applying two diagnostic tests to a well-defined group of diseased patients produce a pair of sensitivity and by applying the same medical tests to a group of non-diseased subjects produce a pair of specificity. The statistical tests in the meta-analysis need to consider the correlatedness of the results from two diagnostic tests applied to the same diseased and non-diseased subjects. The associations between two diagnostic test results are often found to be unequal for the diseased and non-diseased subjects. In this paper, multivariate meta-analytic methods are studied by taking into account the different associations between correlated variables. On the basis of Monte Carlo simulations, we evaluate the performance of the multivariate meta-analysis methods proposed in this paper.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.10
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• pp.5075-5079
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• 2012

Purpose: The results of recent published studies focusing on IL-8 polymorphism in colorectal cancer susceptibility have often been inconsistent. We therefore carried out a meta-analysis based on independent studies to assess the association. Methods: Nine case-control studies with 7,003 individuals (3,019 cases and 3,984 controls) were included in this meta-analysis through searching the databases of PubMed, Excerpta Medica Database (EMBASE), and Chinese Biomedical Literature Database (CBM; Chinese) (up to Aug 1st, 2012). The odds ratio (OR) and 95% confidence interval (95%CI) were used to assess the strength of the association. Meta-analysis was conducted in a fixed/random effect model. Results: No obvious associations were found for all genetic models when all studies were pooled into the meta-analysis (for A vs. T: OR = 1.084, 95% CI = 0.971-1.209, P = 0.019; for TA vs. TT: OR = 1.18, 95% CI = 0.943-1.475, P = 0.001; for AA vs. TT: OR = 1.155, 95% CI = 0.916-1.456, P = 0.014; for AA+TA vs. TT: OR = 1.170, 95% CI =0.953-1.437, P = 0.001; for AA vs. TT+TA: OR = 1.044, 95% CI = 0.886-1.230, P = 0.097). In the subgroup analyses by ethnicity (Caucasian) and source of controls (population based), also no significant associations were found for all genetic models. Conclusions: Result suggests that the IL-8-251T>A polymorphism is not associated with colorectal cancer risk. Because of the limitations of this meta-analysis, this finding demands further investigation.

• Nutrition Research and Practice
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• v.17 no.1
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• pp.62-72
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• 2023

BACKGROUND/OBJECTIVES: Many studies have revealed an association between fat mass and the obesity-related gene (FTO) and obesity. On the other hand, no meta-analysis was conducted with data from only Koreans. Therefore, this study performed a meta-analysis using Korean data to provide evidence for the association between FTO single nucleotide polymorphisms (SNPs) and the risk of obesity among Korean adults. SUBJECT/METHODS: Meta-analysis was finally conducted with data extracted from seven datasets of four studies performed on Korean adults after the screening passed. Five kinds of FTO SNPs (rs9939609, rs7193144, rs9940128, rs8050136, and rs9926289) were included, and the relationship between FTO SNPs and body mass index (BMI) was investigated using linear regression with an additive model adjusted for covariants, such as age, sex, and area. RESULTS: The minor alleles of FTO SNPs were associated with increased BMI (odds ratio [OR], 1.31; 95% confidence interval [CI], 1.21-1.42). In sub-group analysis, FTO rs9939609 T>A was significantly associated with BMI (OR, 1.23; 95% CI, 1.06-1.42). The other FTO SNPs together were significantly associated with BMI (OR, 1.37; 95% CI, 1.25-1.49). The publication bias was not observed based on Egger's test. CONCLUSIONS: This meta-analysis showed that minor alleles in the FTO SNPs were significantly associated with an increased BMI among Korean adults. This meta-analysis is the first to demonstrate that minor alleles in the FTO SNPs contribute significantly to the increased risk of obesity among Korean adults using data from a Korean population.

• Journal of Oriental Neuropsychiatry
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• v.33 no.1
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• pp.49-78
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• 2022

Objectives: This study was conducted to evaluate the efficacy of Korean Medicine Therapy (KMT) for the treatment of Chemotherapy-induced Cognitive Impairment (CICI) through systematic review and meta-analysis of randomized controlled trials (RCTs) as proceeding research to further research the efficacy of KMT for CICI patients. Methods: We conducted a systematic review and meta-analysis according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines (PRISMA). The RCTs on the efficacy of KMT for treatment of CICI were searched by structured search strategies in MEDLINE, EMBASE, Cochrane library, CAJD, KISS, NDSL, KoreaMed, and OASIS. The searched RCTs were screened by inclusion and exclusion criteria. We evaluated the quality of the method in the included studies using the Jadad score and Cochran ROB tool. The efficacy outcomes were the Visual Analogue Scale (VAS) and the Clinical total Effective Rate (CER) of CICI. They were analyzed using mean difference for continuous variable or Relative Risk (RR) for Dichotomous variable in the random-effect model. The RevMan 5.3 program was used for meta-analysis. Results: We included 19 RCTs, including 653 participants, in the systematic review and meta-analysis. There were favorable results for the KMT group after the intervention compared with the pharmacotherapy group, physiotherapy group, and combined treatment group. KMT group showed improvement using CER and VAS compared with exercises, but their heterogeneities were slightly significant. KMT was more effective compared to the Rehabilitation program in CER and the subgroup analysis results showed that KMT had a significant difference compared to other therapies in VAS, to Medication therapy in CER. Conclusions: KMT presented reasonable evidence on improving the Clinical total Effective Rate and Visual Analogue Scale in CICI patients. However, further evaluation in future research is required.