• Geomechanics and Engineering
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• v.7 no.5
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• pp.525-537
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• 2014

The typical design of ground improvement with prefabricated vertical drains (PVD) and surcharge preloading involves a series of deterministic analyses using averaged or mean soil properties for the various combination of the PVD spacing and surcharge preloading height that would meet the criteria for minimum consolidation time and required degree of consolidation. The optimum design combination is then selected in which the total cost of ground improvement is a minimum. Considering the variability and uncertainties of the soil consolidation parameters, as well as considering the effects of soil disturbance (smear zone) and drain resistance in the analysis, this study presents a stochastic cost optimization of ground improvement with PVD and surcharge preloading. Direct Monte Carlo (MC) simulation and importance sampling (IS) technique is used in the stochastic analysis by limiting the sampled random soil parameters within the range from a minimum to maximum value while considering their statistical distribution. The method has been verified in a case study of PVD improved ground with preloading, in which average results of the stochastic analysis showed a good agreement with field monitoring data.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.5
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• pp.1043-1053
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• 1994

This study suggests a practical but rational approach for the development of reliability-based LRFD criteria for transmission towers under wind and ice loadings in Korea. Based on available statistical data on wind speed and icing on transmission lines in Korea, the design wind and ice loads are obtained by Monte Carlo Simulations. In the study, the AFOSM reliability method and an Importance Sampling Technique are used for the element and system reliability evaluation of actual transmission towers. Based on the selected target reliabilities, a set of load and resistance factors for the LRFD criteria are calibrated using the AFOSM and the code optimization technique.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.6
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• pp.635-642
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• 2014

In this paper, an efficient technique is developed to predict failure probability of three failure modes(case rupture, fracture and bolt breakage) related to solid rocket motor case due to the inner pressure during the mission flight. The overall procedure consists of the steps: 1) design parameters affecting the case failure are identified and their uncertainties are modelled by probability distribution, 2) combustion analysis in the interior of the case is carried out to obtain maximum expected operating pressure(MEOP), 3) stress and other structural performances are evaluated by finite element analysis(FEA), and 4) failure probabilities are calculated for the above mentioned failure modes. Axi-symmetric assumption for FEA is employed for simplification while contact between bolted joint is accounted for. Efficient procedure is developed to evaluate failure probability which consists of finding first an Most Probable Failure Point(MPP) using First-Order Reliability Method(FORM), next making a response surface model around the MPP using Latin Hypercube Sampling(LHS), and finally calculating failure probability by employing Importance Sampling.

• Journal of the Korean Society of Food Culture
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• v.34 no.4
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• pp.411-423
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• 2019

This study conducted qualitative research through in-depth interviews on the diffusion process of Korean food in accordance with the length of residence of Chinese students in Korea. As the analysis method, the qualitative analysis method such as NVivo12.0 was used, and the analysis was performed through word frequency, word cloud, and coding matrix. The images of taste of Korean food were revealed as 'Spicy', 'Sweet', and 'Light taste' by both short-term Chinese residents and long-term Chinese residents. The long-term Chinese residents showed their dissatisfaction with the institutional food, and they also pointed out the importance of the matter of cooking for quick adaptation to life in Korea. The long-term Chinese residents also thought of Korean food as 'High-fiber food', and this was influenced by the 'Less-oil' cooking method of Korean food, which is different from the cooking method of Chinese food. The length of residence was used as a main variable of this study, and it was one of the factors having positive effects on the diffusion of Korean food and acculturation. It would be difficult to generalize the results because this study used the convenience sampling method and snowball sampling.

• Communications for Statistical Applications and Methods
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• v.20 no.1
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• pp.29-39
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• 2013

This paper derives maximum likelihood estimators (MLEs) and some approximate MLEs (AMLEs) of unknown parameters of the generalized exponential distribution when data are lower record values. We derive approximate Bayes estimators through importance sampling and obtain corresponding Bayes predictive intervals for unknown parameters for lower record values from the generalized exponential distribution. For illustrative purposes, we examine the validity of the proposed estimation method by using real and simulated data.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.04a
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• pp.109-116
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• 1993

구조물의 신뢰도를 평가하는 방법을 살펴보고 각각의 장,단점을 비교한다. 각 방법의 정확성을 평가하는 기준으로 Crude Monte Carlo(CMC)방법을 택하여, Importance Sampling(IS)방법, 그리고 Directional Sampling(DS)방법을 살펴 보고, 1차 근사방법은 현재 많이 사용되고 있는 Rackwitz-Fiessler(RF)방법, Chen과 Lind가 제안한 3-parameter방법(CL), Hohenbichler가 제안한 Rosenblatt 변환방법(RT)을, 그리고 2차 근사방법은 Breitung이 제안한 곡률적합 포물선 (Curvature Fitted Paraboloid,CFP)공식과 Kiureghian이 제안한 점적합 포물선(Point Fitted Paraboloid,PFP)공식, 그리고 Log-Likelihood function을 이용하여 원변수공간에서 파괴확률을 구하는 2차 근사공식(LLF)을 비교한다. 그리고 한계상태식이 불명확할 때 효율적으로 사용할 수 있는 반웅웅답법(Response surface method, RSM)을 살펴본다. 각 방법의 효율성 특히 적용 가능성을 예제를 통해 해석한 결과 추출법의 경우는 DS 방법이, 그리고 근사방법에서는 RSM 방법이 효율적임을 알 수 있었다.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.1
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• pp.141-148
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• 2019

This research proposes a model of SERVQUAL scale calibration and uses the SERVPERF model to study the relationship between quality of ATM service and customer satisfaction. The research uses the combination of qualitative and quantitative methodology with the Cronbach's alpha reliability analysis, Exploratory Factor Analysis (EFA) method; Confirmation Factor Analysis (CFA) and Structural Equation Modeling (SEM) through SPSS and AMOS 20.0 data analysis software. The survey was conducted with 800 questionnaires with the convenient sampling method. The number of remaining sample for analysis was 779 responses of individual customers using ATM card services of Bank for Foreign Trade of Vietnam (Vietcombank) Vinh Long. The results show that the satisfaction of customers using ATM cards of Vietcombank Vinh Long is influenced by 4 factors with the order of importance as follows: (1) Price; (2) Network; (3) Reliability; (4) Empathy. Thereby, the author suggests some managerial implications to Vietcombank Vinh Long management to enhance the ATM service quality, then improve customer satisfaction. This research still has some limitations: (1) The study does not investigate other influencing factors, (2) The convenient sampling method has not been generalized well, (3) The research is only conducted for Vietcombank.

• Journal of Digital Convergence
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• v.14 no.6
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• pp.489-498
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• 2016

The purpose of this study was to evaluate selective attributes importance and satisfaction of University Ski Lecture Environment that students perceive using IPA method. In order to achieve this goal, a questionnaire was used to gather data, and the convenient sampling method was used to select 300 members from three pertinent university in Seoul and Chungcheong-do, Gyeongsang-do Province as participants of this study. Only data from 221 respondents however were used after screening data for reliability, and SPSS for Windows(21.0 version) statistical program was used to conduct descriptive analysis, factor analysis, reliability analysis, paired samples t-test analysis, independent samples t-test analysis and IPA matrix analysis. The following results were obtained. First, significant differences between the level of satisfaction and the level of importance were found for part of the selection attributes for each group. Second, Iquadrant was included with meals and information provided factors. IIquadrant was included with instructors and class program, information provided, accommodation factors. IIIquadrant was included in accommodation and meals, time-distance factors. IVquadrant was included in the information provided factor.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.2
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• pp.589-600
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• 2015

The purpose of this study was to verify the analysis of differences between importance and satisfaction of destination attractiveness for the national marine sports games using IPA method. By doing so, this study aimed to utilize the result of study for a practical marketing strategy in operating and establishing Korean marine sports market circumstances. The participants of this study consisted of 328 who were participated in marine sport event (yacht, fin-swimming, canoe, triathlon and so on) of 9th national marine sports games. Samples were extracted by convenient sampling method. A total 328 questionnaires were collected in this study except data which did not respond or trustless responded. In data processing, Cronbach's ${\alpha}$, frequency analysis, paired t-test and Importance-Performance Analysis were performed through SPSS 20.0. The results were as follows. First, I quadrant included Programs Multiplicity, Pamphlet, Stand preparations, Food Cleanliness, Effective Progress, Guide Know-How, Food taste. Third, II quadrant included Pre-Publicity, Internet Information, Proper Food Price, Shade Facilities, Convenient Parking, Restroom Cleanliness, Number of Restroom, Safety Facilities. Fourth, III quadrant included Entertaining Program, Number of Guide, Local Culture, Game Progress, Directional Sign. Fifth, IV quadrant included Performance Program, Well-Matched Event, View Distance, Various Food.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.2 no.2
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• pp.131-137
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• 1995

Improving validity and reliability is the important components of clinical laboratory tests. And the quality control of the test should be started with the accurate collection of specimen. Urinalysis is one of the useful and common tests in diseases diagnosis and determining the process of medical treatment. Since urinalysis is requested routinely in hospital setting, the importance of the quality control for urine specimen is often ignored. To improve the validity of urinalysis, a clinical trial was done on the method of collecting urine specimen. The result was as follows : 1. The rate of presumtive UTI(urinary tract infection) was decreased in 21.6% with experiment method for collecting urine specimen. 2. The rate of presumtive UTI in female patients was decreased in 43.2% with the experiment method. 3. The rate of negative urine culture was decreased in 6.6% with the experiment method.