• Journal of the Korean Ceramic Society
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• v.47 no.3
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• pp.216-222
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• 2010

Portland cement has been restricted in applications to ecological area because of its environmental harmfulness and the $CO_2$ emission during a production process. Geopolymer materials attract some attention as an inorganic binder due to their superior mechanical and eco-friendly properties. In this study, geopolymer-based cement was prepared by using aluminosilicate minerals (flyash, meta-kaolin) with alkaline-activators and its compressive strength with concentration of alkaline-activators was investigated. Aluminosilicate-based geopolymers were obtained by mixing aluminosilicate minerals, alkaline solution (NaOH or KOH with different concentration) and water-glass under the vigorous stirring for 20 min. Compressive strength after curing at $30^{\circ}C$ for 3 days increased with the concentration of alkaline-activator due to the enhanced polymerization of the aluminosilicate materials and dense microstructure. Aluminosilicate-based geopolymer cement using KOH as an alkaline-activator showed high compressive strength compared with NaOH activator. In addition, geopolymer cement using fly-ash as a raw material showed higher compressive strength than that of meta-kaolin.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.387-392
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• 2005

Double-deck train have studied in the next generation train in KRRI. Double-deck train have more seat capacities compared with single deck vehicles and is a efficient, reliable and comfortable alternative train. Because of heavy weight, weight minimization of double-deck train carbody is imperative to reduce cost and extend life-time of train. Weight minimization problem of the double-deck train car-body is required to decide 66 design variables of thicknesses for large aluminum extruded panel while satisfying stress constraints. Design variables are too many and one execution of structural analysis of double-deck train carbody is time-consuming. Therefore, we adopt approximation technique to save computational cost of optimization process. Metamodels such as response surface model (RSM) and kriging model are used to approximate model-based optimization is described. RSM is easy to obtain and expressed explicit function, but this is not suitable for highly nonlinear and large scaled problems. Kriging model employs an interpolation scheme and is developed in the fields of spatial statistics and geostatistics. Target of this design is to find optimum thickness of AEP to minimize weight of doulbe-deck train carbody. In this study, meta model techniques are introduced to carry out weight minimization of a double-deck train car-body.

• Journal of the Korean Society for information Management
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• v.16 no.1
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• pp.157-174
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• 1999

This investigation used meta-analysis to examine the quality of data of domestic ST(Science & Technical) databases. Analyses measured the quality of data itself, determined whether these databases have any critical errors in terms of accuracy, completeness, and consistency by conducting the data retrieval experiments. The purpose of this study was to diagnose the science & technical databases and to find out the problems of them and also to provide possible suggestions for their improvements. The researcher concluded the results by mentioning the three research questions.

• Journal of Korean Institute of Industrial Engineers
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• v.43 no.3
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• pp.192-202
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• 2017

This study develops a text spam filtering system for Facebook based on two variable categories: keywords learned from Instagram and meta-information of Facebook posts. Since there is no explicit labels for spam/ham posts, we utilize hash tags in Instagram to train classification models. In addition, the filtering accuracy is enhanced by considering meta-information of Facebook posts. To verify the proposed filtering system, we conduct an empirical experiment based on a total of 1,795,067 and 761,861 Facebook and Instagram documents, respectively. Employing random forest as a base classification algorithm, experimental result shows that the proposed filtering system yield 99% and 98% in terms of filtering accuracy and F1-measure, respectively. We expect that the proposed filtering scheme can be applied other web services suffering from massive spam posts but no explicit spam labels are available.

• The Journal of the Korea Contents Association
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• v.20 no.10
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• pp.247-258
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• 2020

The purpose of this study is to synthesize and specifically analyze the effects of elementary SW-STEAM Education on learning outcomes by using meta-analysis. 29 papers are selected and total of 60 effect sizes are deduced. Total effect size is a medium effect of .35, which reveals significant effect on the cognitive and affective domains, and 8 moderator variables explain the difference in total effect sizes as well. The results show that SW-STEAM education is effective for elementary students' learning outcomes. Practical implication for design and implementation are addressed.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.3
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• pp.1141-1144
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• 2014

Background: Even though many studies have examined the possible effect of low-fat diet on breast cancer survival, the relationship remains unclear. Objectives: To summarize the current evidence about the effect of post-diagnostic low-fat diet on recurrence and all-cause mortality of breast cancer. Methods: We conducted a search of Pubmed, Embase, Web of Science, and Cochrane Library and as a result two randomized controlled trials (RCT) and one large multi-center prospective cohort study with 9,966 breast cancer patients were included in this report. Results: Post-diagnostic low-fat diet reduced risk of recurrence of breast cancer by 23% (HR=0.77, 95%CI 0.63 to 0.94, P=0.009) and all cause mortality of breast cancer by 17% (HR=0.83, 95%CI 0.69 to 1.00, P=0.05). Conclusions: This meta-analysis suggested the post-diagnostic low-fat diet can improve breast cancer survival by reducing risk of recurrence. However, more trials of the relationship between low-fat diet and allcause mortality of breast cancer are still needed.

• Journal of the Korean Society of Systems Engineering
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• v.11 no.1
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• pp.25-31
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• 2015

Under the relevant regulations, it is required to develop a system architecture for the research and development of the information and communication infra system ; however, the national defense architecture development guides and MND-AF, which provide the instructions on the development and utilization of a system architecture, are still limited to the ITA level and merely providing the guidelines for developing the information system centric architecture. Thus, it is evident that we need a suitable architecture development methodology that corresponds to the growing needs for the communication infra system architecture, as well as the general weapon system architecture. Improving a meta-model is the core of improving a architecture framework. It determines a contents of a architecture and it influences a efficiency and a effectiveness of a architecture. The meta-model of the architecture framework must reflect concerns of various stakeholders and provide a traceability among them. Also, it should be easy to develop and use the architecture by securing the feasibility of the logical relationships and eliminating the duplication of the data inside the architecture. It is implemented through the development of the data-centric architecture and achieved through the "Fit-for-purpose" concept.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.11
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• pp.4665-4669
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• 2015

The aim of this study was to assess the diagnostic value of RASSF1A methylation in renal cell carcinoma. Systematically search were performed using the Pubmed, ProQest and Web of Science for all articles on the association between RASSF1A methylation and renal cell carcinoma before 15 April 2015. After the filtration, 13 studies involving 677 cases and 497 controls met our criteria. Our meta-analysis suggested that hypermethylation of RASSF1A gene was associated with the increased risk of RCC(OR:4.14, 95%CI:1.06-16.1). Stratified analyses showed a similar risk in qualitative detection method(OR:28.4, 95%CI:10.2-79.6), body fluid sample(OR:12.8, 95%CI:5.35-30.8), and American(OR:10.5, 95%CI:1.97-55.9). Our result identified that RASSF1A methylation had a strong potential in prediction the risk of Renal cell carcinoma.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.24 no.2
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• pp.95-105
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• 2017

Purpose: A systematic literature review and meta-analysis were conducted to synthesis research findings on relationships of quality of life with multi-dimensional correlates in Korean breast cancer patients. Methods: For the study purpose, 18 studies were selected through a systematic process of searching the literature. Results: Among the general characteristics, variables having a significant relationship with quality of life were age (ES=.19), marital status (ES=.15), education (ES=.19), economic status (ES=.16), job status (ES=.10), and religion (ES=.13). Among the disease characteristics, type of treatment (ES=.12), length of time since diagnosis (ES=.13), stage of disease (ES=.14), length of time since operation (ES=.10), frequency of treatment (ES=.19), wound site and pain (ES=.16) were shown to have a significant relationship with quality of life. Depression (ES=-.60), one of the psychological factor, was the variable most significantly related to quality of life. Conclusion: The findings indicate that the variables which strongly impact quality of life in breast cancer patients are depression and pain.

• International Commerce and Information Review
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• v.11 no.1
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• pp.485-515
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• 2009

In this study aims to research and analyze what are decision factors between a wholly-owned subsidiary and a international company cooperation in the internationalization process. From 57 primary studies found 26 observed variables for aggregation of effect size in the using "Fixed Effect Model" on this mata-analysis. The article also links the theories that are used in the literature, not considered in the most of primary studies, to the empirical results and recommends global management strategy which is needed for business practical affairs. According to the result, the meta-analysis suggests that the number of employees of a MNC, the geological and cultural differneces between the host country and home country, the country-specific international experience of the MNC and export intensity, the international product diversification, the market growth and the market size of the foreign operations, and resource intensity of the foreign operations, the legal restrictions in the host country and the country risk of the home country do exert a significant effect on the decision between cooperative arrangement and a wholly-owned subsidiary. Conversely, for a large number of variables, no significant relationship seems to exist based on the combined results. This is the case, for example, for factor specificity, the r&d-intensity, the subsidiary size, the assets of the MNC and the sales volume of the MNC.