• 한국소음진동공학회논문집
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• 제21권11호
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• pp.1051-1058
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• 2011

The military communication equipment is required the high reliability for operating adequate functions under severe conditions. This reliability is the essential element for the quality of the product, for the uncontrolled factors, such as the clearance, damage of the material, the reduction of stiffness, which are the designer is unable to handle. In this paper, the uncertainty for the dimension was supposed to the probability model for the military communication equipment, and the average of the objective function was minimized for reducing design uncertainty. The reliability-based design optimization which was implemented the limit state function was formulated into the mathematical model, so the reliable optimized structure was implemented than the base-line design.

• 한국철도학회논문집
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• 제17권4호
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• pp.223-227
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• 2014

제동 패드는 철도차량의 기초제동요소 중 하나이다. 제동 패드는 제동 캘리퍼로부터 압부력을 전달받아 제동디스크와의 마찰력으로 철도차량에 제동작용을 한다. 따라서 제동 패드는 주어진 고압의 압부력을 견뎌야 하므로 제동 패드의 주요 성능평가항목으로 압축강도를 관리한다. 압축강도를 측정하는 규격은 KRS, KRCS, KRT 등이 있다. 이들 규격은 압축강도를 측정하기 위한 시험편의 크기를 $20mm{\times}10mm{\times}15mm$ (가로${\times}$세로${\times}$높이)로 규정하고 있다. 압축강도에 대한 불확도를 줄이기 위하여 불확도 요인을 분석한 결과, 단면의 치수를 변경함으로써 불확도를 줄일 수 있음을 알았다. 새로운 단면치수에 의한 불확도를 평가하여 불확도 감소에 대한 유효성을 입증하였다.

• Structural Engineering and Mechanics
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• 제76권4호
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• pp.529-540
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• 2020

Concurrent topology optimization of macrostructure and microstructure has attracted significant interest due to its high structural performance. However, most of the existing works are carried out under deterministic conditions, the obtained design may be vulnerable or even cause catastrophic failure when the load position exists uncertainty. Therefore, it is necessary to take load position uncertainty into consideration in structural design. This paper presents a computational method for robust concurrent topology optimization with consideration of load position uncertainty. The weighted sum of the mean and standard deviation of the structural compliance is defined as the objective function with constraints are imposed to both macro- and micro-scale structure volume fractions. The Bivariate Dimension Reduction method and Gauss-type quadrature (BDRGQ) are used to quantify and propagate load uncertainty to calculate the objective function. The effective properties of microstructure are evaluated by the numerical homogenization method. To release the computation burden, the decoupled sensitivity analysis method is proposed for microscale design variables. The bi-directional evolutionary structural optimization (BESO) method is used to obtain the black-and-white designs. Several 2D and 3D examples are presented to validate the effectiveness of the proposed robust concurrent topology optimization method.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.602-607
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• 2008

A technique for reliability-based design optimization(RBDO) is developed based on the Bayesian approach, which can deal with the epistemic uncertainty arising due to the limited number of data. Until recently, the conventional RBDO was implemented mostly by assuming the uncertainty as aleatory which means the statistical properties are completely known. In practice, however, this is not the case due to the insufficient data for estimating the statistical information, which makes the existing RBDO methods less useful. In this study, a Bayesian reliability is introduced to take account of the epistemic uncertainty, which is defined as the lower confidence bound of the probability distribution of the original reliability. In this case, the Bayesian reliability requires double loop of the conventional reliability analyses, which can be computationally expensive. Kriging based dimension reduction method(KDRM), which is a new efficient tool for the reliability analysis, is employed to this end. The proposed method is illustrated using a couple of numerical examples.

• 성인간호학회지
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• 제13권2호
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• pp.200-208
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• 2001

The purpose of this study was to understand the nature and structure of "uncertainty of chronically ill patients" by explaining it more scientifically. This study is based on the unique experiences, which individual uncertainty experiences differ from others. In this sense, Q-methodology which includes self-psychology and abductive logics is applied to the study. The results indicate that there are six types of uncertainty of chronically ill patients : my own fault, self-esteem loss, self-care determination, cure-doubt, reality-restructure, and past-tenacity reality-absence. Thus, "uncertainty of chronically ill patients" is defined from the study as the process in which continuous transition and evaluation of possibility cause changes in human recognition, attitude, action, etc.. The significance of the study is threefold : (1) discovery of six types of uncertainty of chronically ill patients in Korean people, (2) the better understanding of "uncertainty of chronically ill patients", (3) possible developments of nursing concept and assessment and intervention technique based on the new dimension of the understanding in uncertainty for nursing of chronically ill patients from this research.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.861-862
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• 2012

• East Asian Economic Review
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• 제28권1호
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• pp.95-140
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• 2024

This study empirically investigates the international transmission of China's uncertainty shocks. It estimates a time-varying parameter Bayesian global structural vector autoregressive model (TVP-BGVAR) using time series data for 33 countries to evaluate heterogeneous international linkage across countries and time. Uncertainty shocks are identified via sign restrictions. The empirical results reveal that an increase in uncertainty in China negatively affects the global economy, but those effects significantly vary over time. The effects of China's uncertainty shocks on the global economy have been significantly altered by China's WTO accession, the global financial crisis, and the recent US-China trade conflict. Furthermore, the effects of China's uncertainty shocks, typically on inflation, differ significantly across countries. Moreover, Trade openness appears crucial in explaining heterogeneous GDP responses across countries, whereas the international dimension of monetary policy appears to be important in explaining heterogeneous inflation responses across countries.

• 유통과학연구
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• 제17권4호
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• pp.59-68
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• 2019

Purpose - The purpose of this study is to examine the differential mediating effects of three dimensions of buyer trust in the influence of supplier characteristics on the relationship performance. In this study, transaction characteristics were classified into competences and assets. The corporate reputation is considered as intangible assets, the customer-linking capability is considered among the competencies and transaction specific asset is selected from tangible assets. This study is also to examine the moderating effect of technical environment uncertainty in the effects of integrity and benevolence on the intention to continue trading. This study aims to provide a guide on which dimension suppliers should manage and how to improve their trust in order to maintain business with companies in technical environment uncertainty. Research design, data, and methodology - The data for the empirical analysis of this study were obtained by interviewing the 274 purchasing managers of Daegu - Gyeongbuk small and medium enterprises. The items used in this survey were partially modified to fit the characteristics of the B2B industry. The reliability and validity of the variables were analyzed using SPSS 18.0 and AMOS 18.0 programs and hypotheses were verified through the structural equation modeling. Results - In this study, reliability was examined by Cronbach 'α test. Composite Reliability and Average Mean Variance extracted value exceeded the baseline values. As a result of hypotheses testing, the hypothesis that the transaction specific asset will improve the benevolence and that benevolence will improve the intention to continue the transaction were rejected and all the other 9 hypotheses were adopted include 2 moderating hypothesis. Conclusions - This study shows which dimension of trust suppliers should appeal to the buyer according to the uncertainty of the technology environment in order to maintain the transaction with the buyer. competence and integrity are important when technology environment uncertainty is low, and competence and benevolence are important when technical environment uncertainty is high. In order to improve competence, corporate reputation and transaction-specific asset are important. To improve integrity, corporate reputation and customer-linking capability are important. In order to improve benevolence, customer-linking capability is important. And various implications were discussed.

• Journal of Information Technology Applications and Management
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• 제21권2호
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• pp.149-165
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• 2014

This paper has studied whether cultural factors have an effect on privacy concern of Internet users in Korea and China. The result has shown that power distance, individualism, uncertainty avoidance, and long-term orientation are positively related to privacy concern, while masculinity is negatively related to privacy concern. This study has also found some similarities and differences between the two countries. First, privacy concern of Korean Internet users is significantly higher than that of Chinese users. Second, individualism and uncertainty avoidance significantly affect privacy concern in both Korea and China, although individualism in Korea has stronger effect than that in China. Third, long term orientation has a significant effect in only Korea while power distance is significant only in China. These results suggest that an online company doing businesses in multiple countries should have country-specific privacy policies to deal with the privacy concern of Internet users in different countries.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.422-427
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• 2008

This study is to illustrate the usefulness of Kriging Dimension Reduction Method(KDRM), which is to construct probability distribution of response function in the presence of the physical uncertainty of input variables. DRM has recently received increased attention due to its sensitivity-free nature and efficiency that considerable accuracy is obtained with only a few number of analyses. However, the DRM has a number of drawbacks such as instability and inaccuracy for functions with increased nonlinearity. As a remedy, Kriging interpolation technique is incorporated which is known as more accurate for nonlinear functions. The KDRM is applied and compared with MCS methods in a compression coil spring design problem. The effectiveness and accuracy of this method is verified.