• The Journal of the Korea Contents Association
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• v.22 no.7
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• pp.18-29
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• 2022

The purpose of this exploratory study is to examine the intellectual structure of data science. For this purpose, this research examined a total of 17,997 bibliographies on data science indexed in Web of Science(WoS) of Clarivate Analytics from 2012 to 2021. This research applied methods such as descriptive analysis, citation analysis, co-author network analysis, co-occurrence network analysis, bibliographic coupling analysis, and co-citation analysis. This research contributes to finding the research directions of future data science topics.

• Physical Therapy Rehabilitation Science
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• v.11 no.3
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• pp.285-295
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• 2022

Objective: The purpose of this study is to use logistic regression and decision tree analysis to identify the factors that affect the success or failurein the national physical therapy examination; and to build and compare predictive models. Design: Secondary data analysis study Methods: We analyzed 76,727 subjects from the physical therapy national examination data provided by the Korea Health Personnel Licensing Examination Institute. The target variable was pass or fail, and the input variables were gender, age, graduation status, and examination area. Frequency analysis, chi-square test, binary logistic regression, and decision tree analysis were performed on the data. Results: In the logistic regression analysis, subjects in their 20s (Odds ratio, OR=1, reference), expected to graduate (OR=13.616, p<0.001) and from the examination area of Jeju-do (OR=3.135, p<0.001), had a high probability of passing. In the decision tree, the predictive factors for passing result had the greatest influence in the order of graduation status (x²=12366.843, p<0.001) and examination area (x²=312.446, p<0.001). Logistic regression analysis showed a specificity of 39.6% and sensitivity of 95.5%; while decision tree analysis showed a specificity of 45.8% and sensitivity of 94.7%. In classification accuracy, logistic regression and decision tree analysis showed 87.6% and 88.0% prediction, respectively. Conclusions: Both logistic regression and decision tree analysis were adequate to explain the predictive model. Additionally, whether actual test takers passed the national physical therapy examination could be determined, by applying the constructed prediction model and prediction rate.

• Wind and Structures
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• v.6 no.2
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• pp.141-150
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• 2003

This paper presents galloping analysis of multiple-degree-of-freedom (MDOF) structural roofs with multiple orientations. Instead of using drag and lift coefficients and/or their combined coefficient in traditional galloping analysis for slender structures, this study uses wind pressure coefficients for wind force representation on each and every different orientation roof, facilitating the galloping analysis of multiple-orientation roof structures. In the study, influences of nonlinear aerodynamic forces are considered. An energy-based equivalent technique, together with the modal analysis, is used to solve the nonlinear MDOF vibration equations. The critical wind speed for galloping of roof structures is derived, which is then applied to galloping analysis of roofs of a stadium and a high-rise building in China. With the aid of various experimental results obtained in pertinent research, this study also shows that consideration of nonlinear aerodynamic forces in galloping analysis generally increases the critical wind speed, thus enhancing aerodynamic stability of structures.

• Korean Journal of Computational Design and Engineering
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• v.18 no.2
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• pp.138-147
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• 2013

The liquefaction process system is regarded as primary among all topside systems in LNG FPSO. This liquefaction process system is composed of many types of equipment. LNG equipment on offshore plants has quite different demands on the equipment compared to traditional onshore LNG plants, so the reliability analysis of this process system needs to be performed. This study investigates how DEVS formalism for discrete event simulation can be used to reliability analysis of the liquefaction cycle for LNG FPSO. The reliability analysis method based on DEVS formalism could be better model for reflecting the system configuration than the conventional reliability analysis methods, such as fault tree analysis and event tree analysis.

• Journal of Environmental Science International
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• v.15 no.3
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• pp.261-269
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• 2006

In this study, an optimization technique was developed from the application of allocation rule. The results obtained from the water supply analysis and reliability indices analysis of Andong dam and Imha dam which are consist of parallel reservoir system are summarized as the followings; Allocation rule(C) is effective technique at the parallel reservoir system because results of the water supply analysis, storage analysis and reliability indices analysis is calculated reasonable results. Also, reliability indices analysis results are not sufficient occurrence based reliability or quantity based reliability. Thus reliability indices analysis are need as occurrence based reliability, quantity based reliability vulnerability, resilience, average water supply deficits and average storage. And water supply condition is better varying water supply condition than constant water supply condition.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.8
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• pp.1296-1302
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• 2008

This paper deals with modeling and dynamic characteristic analysis of a large-powered LNG electric ship propulsion system. Basically, we perform to verify the adequacy of system modeling on the sea going mode and LNG unloading mode based on load flow analysis. And then, we observe the dynamic characteristic of system to perform motor starting analysis and transient stability analysis. Particularly, this paper examine analysis results in comparison with the IEEE standard 141 and the class rule. Hence, this paper has evaluated stability of the electric ship propulsion system at static and dynamic conditions.

• International Journal of Contents
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• v.13 no.3
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• pp.43-48
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• 2017

As a computational approach to literary criticism, the method of character network analysis has attracted attention. The character network is composed of nodes as characters and links as relationship between characters, and has been used to analyze literary works systematically. However, there were limitations in that relationships between characters were so superficial that they could not reflect intimate relationships and quantitative data from the network were not interpreted in depth regarding meaning of literary works. In this study, we propose an improved method of character network analysis through a case study on the play . First, we segmented the character network into a dialogue network focused on speaker-to-listener relationship and an opinion network focused on subject-to-object relationship. We analyzed these networks in various ways and discussed how analysis results could reflect structure and meaning of the work. Through these studies, we strived to find a way of organic and meaningful connection between literary criticism in humanities and network analysis in computer science.

• Journal of the Korean Society of Safety
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• v.32 no.3
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• pp.54-59
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• 2017

This paper presents an efficient finite analysis model and a simulation-based reliability analysis method for stowage device system failure of a container crane with respect to lateral load. A quasi-static analysis model is introduced to simulate the nonlinear resistance characteristics and failure of tie-down and stowage pin, which are the main structural stowage devices of a crane. As a reliability analysis method, a subset simulation method is applied considering the uncertainties of later load and mechanical characteristic parameters of stowage devices. An efficient Markov chain Monte Carlo (MCMC) method is applied to sample random variables. Analysis result shows that the proposed model is able to estimate the probability of failure of crane system effectively which cannot be calculated practically by crude Monte Carlo simulation method.

• Proceedings of the Safety Management and Science Conference
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• 2011.11a
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• pp.213-217
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• 2011

The research shows misuse cases of quantitative regression analysis used in QC circle activity and six sigma movement which presents guidelines of correct use for quality practitioners. Additionally, the qualitative regression analysis that responses nonconforming ratio of variable y, is reviewed based on misuse cases for proper use by practitioners in the field. In most cases, there are frequent errors that involve the correlation analysis or ANOVA, regardless of using quantitative regression analysis. In addition, qualitative regression analysis for the nonconforming ratio that has dependent variable of discrete and categorical data, is often applied with quantitative regression and result in ineffective quality improvement.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.487-494
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• 2003

Recently it is used seismic analysis like single mode spectrum analysis, multi mode spectrum analysis and time history analysis in Korea. Because bridges are not special form of them but regular and simple form of them in our country, we must develope seismic analysis program of bridge based on single nude spectrum analysis. The program developed by this study reduces a Quantity and a time of calculation compared to SAP90 and gives accurate answers without errors. In the case of commercial program if we look for seismic load(P/sub e/(x)), we must increase the number of node and the larger the number of node the more a quantity and a time of calculation. But this program is exactly solved with basic node compared to commercial program.