• Title/Summary/Keyword: importance sampling (IS)

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구조신뢰성 해석방법의 고찰

  • 양영순;서용석
    • 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.

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Effects of Input Variables in Radiological Accident Consequence Assessment

  • Han, Moon-Hee;Hwang, Won-Tae;Kim, Eun-Han;Suh, Kyung-Suk;Park, Young-Gil
    • Proceedings of the Korean Nuclear Society Conference
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    • 1998.05b
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    • pp.659-664
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    • 1998
  • The importance of input wariables of real-time accident consequence assessment model has been analyzed. Partial correlation coefficients of input variables related to the plume and the ingestion exposure have been estimated using latino hypercube sampling technique. It is known that wind speed and growth dilution rate are the most important variable in plume and ingestion exposure, respectively.

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Marginal Likelihoods for Bayesian Poisson Regression Models

  • Kim, Hyun-Joong;Balgobin Nandram;Kim, Seong-Jun;Choi, Il-Su;Ahn, Yun-Kee;Kim, Chul-Eung
    • Communications for Statistical Applications and Methods
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    • v.11 no.2
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    • pp.381-397
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    • 2004
  • The marginal likelihood has become an important tool for model selection in Bayesian analysis because it can be used to rank the models. We discuss the marginal likelihood for Poisson regression models that are potentially useful in small area estimation. Computation in these models is intensive and it requires an implementation of Markov chain Monte Carlo (MCMC) methods. Using importance sampling and multivariate density estimation, we demonstrate a computation of the marginal likelihood through an output analysis from an MCMC sampler.

A Study on Clothing Shopping Motivations and store - Preferred Stores and Store Atmosphere - (소비자의 의류쇼핑동기유형과 점포에 관한 연구 -선호점포와 점포분위기-)

  • 박수경;임숙자
    • Journal of the Korean Society of Clothing and Textiles
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    • v.20 no.3
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    • pp.414-428
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    • 1996
  • This study intends to ascertain the importance of store atmosphere when construcing store marketing strategies for store differentiation. And it is studied by classifying consumer groups according to clothing shopping motivations, comparing store atmosphere assessment and emotion response of preferred stores, and analyzing the influence store atmosphere has on store preference or impulsive purchase. The subject of this study are women in their twenties living in Seoul, 255 career women and 233 college students totaling 458, and model sampling is done by convenient sampling taking into account the type of their occupation and major. Modified survey based on references and former studies is used, and using SAS packages, methods. The results of data analysis are as follows. 1. Consumer groups are classified into the following four subdivisions: shopping involvement, leisure pursuit, financial, and shopping unconcern group. The stores women in twenties use most frequently for shopping are department stores, speciality stores, common market, discount stores, and wholesale markets, and significant difference are shown between consumer groups. 2. Consumer responses for store atmosphere preferences are shown significantly among groups when concerned with store preferences. 3. Images of store atmosphere as factor analyzed into environment factor, kindness factor, and decoration factor, Environment factor is most highly estimated in speciality stores, kindness factor in department stores, and decoration factor in common markets. 4. Leisure pursuit group is assessed to be most influenced by store atmosphere in store seleciton, impulsive purchase, and after-purchase shopping behavior, and impulsive purchase is shown highly in department stores and speciality stores.

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An Evaluation of Planning Factors for Theme Park by means of Importance-Performance Analysis -Focused on the Case of Everland- (중요도-성취도 분석에 의한 주제공원 계획요소 평가 -에버랜드를 사례로-)

  • 오정학;김유일
    • Journal of the Korean Institute of Landscape Architecture
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    • v.29 no.4
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    • pp.34-43
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    • 2001
  • Unlike ordinary recreational facilities, an amusement park consists of various entertainment facilities, attractions, food services, souvenir shops and other attribute. The purpose of this study is to survey users´ responses to such attributes and analyze the importance and performance of each attribute, and thereby, ultimately help improve the efficiency of management and operation of the amusement parks. For this purpose, a survey was conducted of Everland users in August, 1999. 420 users were chosen by means of he systematic sampling. All the suers were asked to rate the importance of 14 attributes of Everland at the entrance and all of them were asked to do the same at the exit. As a result, it was found that the attribute rated highest by the users was ´attraction´, followed by ´service´, ´accessibility´ and ´cost´ in that order. On the other hand, it was found that the total average of importance rated for 14 attributes was 3.31, while that of performance was 3.10. As a consequence of analyzing the action grids, it was found that ´appropriateness of the circulation system´ should be improved most urgently. 7 attributes were categorized as ´keeping up good work´, and 6 ones were rated ´low priority´ in terms of improvement. There was no attribute considered to be ´possible overkill´. Meanwhile, as a result of analyzing the difference among groups in order to determine users´ response depending on their demographic and socio-economic variables, it was found that only the ´age´ variable was significant. It is expected that the results that the results of this study would be useful in determining priorities when improving amusement park facilities or their programs.

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The Antecedent of Employee Engagement and Its Effect on Innovative Behavior: A Religiosity-Based Social Exchange Theory (SET) Perspective

  • ARIFIN, Noor;TJAHJONO, Heru Kurnianto;HARTONO, Arif;MUAFI, Muafi
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.7
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    • pp.313-322
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    • 2021
  • This study aims to analyze the influence of religiosity, spiritual leadership, and work-life balance and its impact on innovative behavior through the mediating effect of employee engagement on the state-owned sharia bank of Central Java Province. The total sample of this study is 226 respondents taken from state-owned sharia bank in 6 Regencies/Cities in the former Karisedenan of Central Java. Samples are taken using a cross-sectional approach. The sampling technique is using the division of regions based on clusters (cities) and is carried out using a purposive sampling method. The results indicate that the indirect influence of all independent variables on innovative behavior through the mediating effect of employee engagement is found to be significant. This study views employee engagement from the perspective of religiosity-based social exchange theory so that religious values in the interaction relationship can be fairly applied and respected by the employees of the state-owned sharia bank. Managers can socialize the importance of spirit behavior to employees so that it can be their everyday attitude and becomes their guide for work. Leaders can become role models in straightening intentions while working as well as conditioning the conscience to always think positively at work by strengthening work engagement in sharia banking institutions.

Perception of Education Community about Teacher's Competency (교사의 핵심역량에 대한 교육공동체의 인식 조사)

  • SUNG, Bung-Chang;BOO, Jae-Yool;HAN, Kyung-Im;LEE, Kyeong-Hwa
    • Journal of Fisheries and Marine Sciences Education
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    • v.21 no.1
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    • pp.78-95
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    • 2009
  • The purpose of this study is to define areas and standards of kindergarten teacher's competency through survey research and interview with early childhood education community - kindergarten teachers, vice principals, principals, administrators, parents, and professors in early childhood education. Raw data from 62 interviewees were grouped into 25 codes including 'professional knowledge about young children's developmental characteristics, and labeled for representative themes. Based on the result of interview analysis, two areas of 'knowledge and skill' area (15 standards) and 'attitude and grounding' area (20 standards) were classified, survey researched for appropriateness and relative importance of each standard. 704 members of early childhood education community were collected through stratified sampling. The research findings indicate that 'observation and evaluation ability for young children' and 'affection for young children' showed high appropriateness in 'knowledge and skill area' and 'attitude and grounding area', respectively. In the relative importance analysis, 'understanding of young children's development', 'understanding of curriculum for young children', and 'understanding of young children's behavioral problem and counseling' for knowledge and skill area, and 'respect for young children', 'affection for young children', responsibility', 'positive attitude' for attitude and grounding area showed high relative importance in order.

Revisiting Deep Learning Model for Image Quality Assessment: Is Strided Convolution Better than Pooling? (영상 화질 평가 딥러닝 모델 재검토: 스트라이드 컨볼루션이 풀링보다 좋은가?)

  • Uddin, AFM Shahab;Chung, TaeChoong;Bae, Sung-Ho
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2020.11a
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    • pp.29-32
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    • 2020
  • Due to the lack of improper image acquisition process, noise induction is an inevitable step. As a result, objective image quality assessment (IQA) plays an important role in estimating the visual quality of noisy image. Plenty of IQA methods have been proposed including traditional signal processing based methods as well as current deep learning based methods where the later one shows promising performance due to their complex representation ability. The deep learning based methods consists of several convolution layers and down sampling layers for feature extraction and fully connected layers for regression. Usually, the down sampling is performed by using max-pooling layer after each convolutional block. We reveal that this max-pooling causes information loss despite of knowing their importance. Consequently, we propose a better IQA method that replaces the max-pooling layers with strided convolutions to down sample the feature space and since the strided convolution layers have learnable parameters, they preserve optimal features and discard redundant information, thereby improve the prediction accuracy. The experimental results verify the effectiveness of the proposed method.

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A Study on Progressive Sampling Method Using Contour Lines (등고선(等高線)을 이용(利用)한 표본추출법(標本抽出法)에 관한 연구(硏究))

  • Lee, Suk Chan;Shin, Bong Ho;Jung, Sung Ho;Cho, Young Ho
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.5 no.2
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    • pp.67-73
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    • 1985
  • In Digital Terrain Model(DTM), more accurate data acquisition method is of importance. This paper has the purpose of accuracy analysis of progressive sampling method, one of data acquisition method. Especially, The following in accuracy analysis are compared and analyzed. -Comparison and analysis for position error between the digital contour lines using digital terrain model and the conventional contour lines using A-10 Plotter. -Analysis for height error of interpolation points according to application of progressive sampling method. For above numerical tests, Computer Program related to auto-carto of contour lines was made up. As a result of tests, threshold and sampling criterion have close of mutual relation to accuracy. Particularly, it was found that auto-carto of contour lines-threshold of 1.0 m and standard criterion-almost concurred in conventional contour lines.

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Social Work Students and Their Attitude toward Research (사회복지전공학생들의 조사연구에 관한 태도 연구)

  • Chung, Soon-Dool
    • Korean Journal of Social Welfare
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    • v.58 no.4
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    • pp.219-236
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    • 2006
  • The purposes of this study are to investigate the research attitude of social work students and to examine the factors associated with research attitude. The subjects of this study are social work students around capital city in Korea. The sampling methods used in this study is a purposive sampling strategy. Data were collected by answering the questionnaire in class. Data from 321 of social work students were finally analyzed by regression analysis. The results show that the level of research attitude by social work students in Korea is relatively lower than previous study. The variables affecting importance and usefulness of research are related to the attitude of research class and the attitude of nature for social work practice. The implications of social work research education are discussed.

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