• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.842-846
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• 2005

A brake disk and a pad are important parts that affect the braking stability of a railway vehicle. Especially, because a brake disk stops the vehicle using conversion of the kinetic energy to frictional energy, thermal fatigue cracks are generated by the cyclic thermal load, as frictional heat, on a frictional surface and these cracks cause the fracture of a brake disk. Therefore, many researches for the thermal stress must be performed to improve the efficiency of brake disk and ensure the braking stability. In this study, we performed the thermal stress analysis for a ventilated brake disk with 3-D analysis model. For that, we simplified the shape of a ventilated hole to minimize problems that could be occurred in analysis process. Thermal stress analysis was performed in case that pressure distributions on a frictional surface is constant and is not. To determine pressure distributions of irregular case, pressure distribution analysis for a frictional surface was carried out. Finally using the results that were obtained through pressure distribution analysis, we carried out thermal stress analysis of each case and investigated the results of thermal stress analysis.

• The Journal of Information Systems
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• v.31 no.4
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• pp.25-45
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• 2022

Purpose In this paper, we propose the method to extend topic modeling techniques in order to derive data-based research hypotheses when establishing research hypotheses for social sciences, As a concept in contrast to the existing deductive hypothesis establishment methodology for the social science research, the topic modeling technique was expanded to enable the so-called inductive hypothesis establishment methodology, and an analysis case of the Seongsan Ilchulbong online review based on the proposed methodology was presented. Design/methodology/approach In this paper, an extension architecture and extension algorithm in the form of extending the existing topic modeling were proposed. The extended architecture and algorithm include data processing method based on topic ratio in document, correlation analysis and regression analysis of processed data for topics derived by existing topic modeling. In addition, in this paper, an analysis case of the online review of Seongsan Ilchulbong Peak was presented by applying the extended topic modeling algorithm. An exploratory analysis was performed on the Seongsan Ilchulbong online reviews through the basic text analysis. The data was transformed into 5-point scale to enable correlation and regression analysis based on the topic ratio in each online review. A regression analysis was performed using the derived topics as the independent variable and the review rating as the dependent variable, and hypotheses could be derived based on this, which enable the so-called inductive hypothesis establishment. Findings This paper is meaningful in that it confirmed the possibility of deriving a causal model and setting an inductive hypothesis through an extended analysis of topic modeling.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.5
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• pp.515-521
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• 2015

The SymMerge algorithm is an efficient merging algorithm for input sequences u and v of sizes $\left|u \right|=m$ and $\left|v \right|=n$, $m{\leq}n$. We consider complexity analysis for SymMerge algorithm regarding to the required number of comparisons. The focus of the previous complexity analysis was on finding the values of upper bounds, i.e. showing the asymptotical optimality. In this paper, in a different way from the previous complexity analysis, we show that the overall required number of comparisons for two representative special cases "symmetric case" and "maximum spanning case" can be calculated exactly i.e. the least upper bounds regarding to the required number of comparisons are calculated. Symmerge requires exactly $m\;log\frac{n}{m}+4m-logm-3$ comparisons for symmetric case of sizes $m=2^k,\;n=2^l,l{\geq}k$ of input sequences and exactly $\frac{1}{2}m^2+(m+1)logm-\frac{3}{2}m+2$ comparisons for maximum spanning case of sizes $m=2^k,n=2^m-m$ of input sequences. Additionally we show that the complexity of the Symmerge algorithm regarding to the overall required number of comparisons for these special cases can be defined by recurrence relations.

• Korean Journal of Social Welfare Studies
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• v.41 no.2
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• pp.5-33
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• 2010

The purpose of this study is to understand the open adoption experience of adoptive families. For this purpose, the data were collected through diverse data collection methods including in-depth interviews with adoptive families who had experiences of open adoption and analyzed using a qualitative case study approach. Data collected from six adoptive families were employed for within-case analysis and cross-case analysis. Each case was carefully examined and summarized using story-telling style in the within-case analysis and major issues for open adoption appeared in each case were described and compared one by one. In the cross-case analysis, all the cases were re-examined keeping the issues appeared in the within-case analysis in mind and eight integrated themes were emerged from it. The eight integrated themes are 'the crucial meeting', 'a clear arrangement', 'an uneasy parallel', 'the other mom', 'who are the real parents?', 'the words never to say', 'the hidden characters', and 'the center of relations or the outsider'. Based on the results of the study, the policies and practical guidelines related to open adoption were suggested. Also, the suggestions for the further studies were made to obtain more abundant information beyond the limitations of the study.

• The Journal of Information Technology and Database
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• v.8 no.2
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• pp.137-159
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• 2001

This study provides a thorough methodology for IT Investment evaluation. A software tool to support the evaluation process was introduced along with a case study. The software supports the methodology that consists of 7 phases : Target analysis, ldentifying IT measures, Measuring IT impact, Assessing business value, Analyzing the decree of realization, Cost-benefit analysis, and Reporting. The case study showed that the software (CAFA) was a very useful tool supporting both decision-making and post-implementation reviews of IT investment.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.743-746
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• 1999

In this paper, Flyback type DC/DC Switching Converter was designed, analyzed and fabricated. Worst Case Analysis(WCA) was peformed with Mathcad program and presents circuit simulation results for the in-rush current limit circuit. The value of the maximum OFF voltage stress is 131.84V, it is less than device specification(200V). The switching frequency(nominal case) and duty cycle at the wont case analysis are 75KHz and 34.62%, respectively. The maximum in-rush current presents 0.5A Those results show a possibility for use in space

• Proceedings of the Korean Society for Language and Information Conference
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• 2007.11a
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• pp.365-374
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• 2007

This paper investigates the nature of Japanese argument cluster (Steedman 2000b). Based on Combinatory Categorial Grammar, a type-raising analysis of case particles which captures some aspects of the information structure in Japanese is discussed, including contrastive interpretation of coordination, wh-constructions, and some theme and rheme-related grammatical phenomena. These observations offer further support for the study of syntax, semantics, and phonology interface and the earlier analysis of English information structure.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.1
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• pp.9-16
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• 2013

Although it is widely accepted that a fire can occur due to electrical causes even when an engine stops, there is little introduction of detailed case analysis. This study analyzed a fire case caused by an electrical cause during engine stopping at parking lot in detail. Moreover, it was revealed that the fire was mainly caused by design defect.

• 한국디지털정책학회:학술대회논문집
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• 2007.06a
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• pp.377-384
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• 2007

This paper is about how to establish the strategic teaming organization in digital age. Through the case study of action teaming, this research can give some implications to small-sized organizations who want to establish teaming culture and positive activities in their own companies. The case site was S-steel, which belongs to the steel industry. To improve and drive teaming activities, I made use of skills: action learning, fishbone analysis, creative thinking, brainstorming, creative discussion skill, and organization diagnostic method.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.193-196
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• 2003

This study aims at analyzing a power system, in case of installing HTS cable in the system First of all, we determine the case that HTS cable can be applied to KEPCO systems and analyze the static state of power system. Then we propose a solution of the problem resulting from the analysis.