• 연구논문집
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• 통권34호
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• pp.59-68
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• 2004

The hot spot stress approach and the notch strain approach are discussed with some results of them. And a stress model that can be applicable to several types of weld joints with single S-N curve of the base material. The stress model uses the geometric characteristics of the stress distribution vicinity of weld joints. The model was applied to five different weld joins(the base material is SM490B). By the representative stress, the experimental fatigue data are plotted very closely to the S-N curve of the base material.

• Communications for Statistical Applications and Methods
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• 제31권1호
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• pp.55-64
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• 2024

In this study, we consider the sample size determination problem for clustered count data with many zeros. In general, zero-inflated Poisson and binomial models are commonly used for zero-inflated data; however, in real data the assumptions that should be satisfied when using each model might be violated. We calculate the required sample size based on a discrete Weibull regression model that can handle both underdispersed and overdispersed data types. We use the Monte Carlo simulation to compute the required sample size. With our proposed method, a unified model with a low failure risk can be used to cope with the dispersed data type and handle data with many zeros, which appear in groups or clusters sharing a common variation source. A simulation study shows that our proposed method provides accurate results, revealing that the sample size is affected by the distribution skewness, covariance structure of covariates, and amount of zeros. We apply our method to the pancreas disorder length of the stay data collected from Western Australia.

• 한국정보시스템학회지:정보시스템연구
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• 제31권2호
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• pp.197-216
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• 2022

Purpose In this study, in order to understand the effects of NTIS users' behavioral scientific behaviors and determinants, an integrated model of the UTAUT(Unified Theory of Acceptance and Use of Technology) model and TTF(Task-Technology Fit) model, which are frequently used MIS field, was presented and empirical analysis was conducted. Design/methodology/approach In this study, an online survey was conducted on researchers from organizations carrying out national R&D projects, institutions, universities, and dedicated management institutions and the collected data verified hypotheses established using the SPSS 25.0 statistical package and structural equation model using AMOS. Findings The results showed that NTIS users' business activities had a positive(+) effect on task-technology fit and task-technology fit had a positive(+) effect on performance expectation, effort expectation, and continuous intention-to-use intention. In addition, the performance expectation, effort expectation, and promotion conditions presented in research model had a positive(+) effect on the continuous intention-to-use. The research results derived through this study are expected to contribute substantially to subsequent research in the field related to information sharing platforms.

• 한국농림기상학회:학술대회논문집
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• 한국농림기상학회 2017년도 추계 학술발표초록집
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• pp.59-60
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• 2017

• Communications for Statistical Applications and Methods
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• 제26권3호
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• pp.325-336
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• 2019

In this article we extend the discrete Weibull regression model in the presence of missing data. Discrete Weibull regression models can be adapted to various type of dispersion data however, it is not widely used. Recently Yoo (Journal of the Korean Data and Information Science Society, 30, 11-22, 2019) adapted the discrete Weibull regression model using single imputation. We extend their studies by using multiple imputation also with several various settings and compare the results. The purpose of this study is to address the merit of using multiple imputation in the presence of missing data in discrete count data. We analyzed the seventh Korean National Health and Nutrition Examination Survey (KNHANES VII), from 2016 to assess the factors influencing the variable, 1 month hospital stay, and we compared the results using discrete Weibull regression model with those of Poisson, negative Binomial and zero-inflated Poisson regression models, which are widely used in count data analyses. The results showed that the discrete Weibull regression model using multiple imputation provided the best fit. We also performed simulation studies to show the accuracy of the discrete Weibull regression using multiple imputation given both under- and over-dispersed distribution, as well as varying missing rates and sample size. Sensitivity analysis showed the influence of mis-specification and the robustness of the discrete Weibull model. Using imputation with discrete Weibull regression to analyze discrete data will increase explanatory power and is widely applicable to various types of dispersion data with a unified model.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.726-729
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• 2004

Spatiotemporal phenomena are ubiquitous aspects of real world. In the spatial and temporal databases, integrity constraints maintain the semantics of specific application domain and relationship between domains when proceed update in the database. Efficient maintenance of data integrity has become a critical problem, since testing the validity of a large number of constraints in a large database and after each transaction is an expensive task. Especially, in spatiotemporal domain, data is more complex than traditional domains and very active. Additionally, it is not considered that unified frameworks deal with both spatial and temporal properties to handle integrity constraints. Therefore, there need a model to maintain integrity constraints in the unified frameworks and enforcement and management techniques in order to preserve consistence.

• Asian Journal for Public Opinion Research
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• 제2권3호
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• pp.196-227
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• 2015

The premise of the intentional model of split-ticket voting is that some voters split their tickets simply because they prefer divided government and believe in constant "checks and balances." This article examines whether this premise stands firm in an emerging democracy like Taiwan. That is, by using survey data in Taiwan, we explore whether one's attitude toward divided or unified government is "real." We hypothesize that a citizen's attitude toward "checks and balances" is subject to change, and conditional on whether her preferred party is in power. Specifically, we speculate that a citizen would tend to hold the balancing perspective or favor divided government, if her preferred party is in opposition. However, if her preferred party becomes the ruling party, she would be more likely to oppose (hold) the balancing (non-balancing) perspective or favor unified government. We then utilize panel survey data embedded in Taiwan's Election and Democratization Studies (TEDS) to verify our hypothesis.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1145-1150
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• 2008

In this paper, We studied efficient design of wireless transmission system for unified data transmission in a subway and railway. It is increased that need of broadband multimedia service to make useful environment for user and to support the operation of railway system. High bandwidth is better if we need more services. But, high bandwidth requires more cost at tunnel of subway. More bandwidth make receive sensitivity to bad. So it need more wireless Station. We deduced best bandwidth of subway wireless transmission system reflecting the cost of installation and efficiency of system. Consequently, we decide efficient service model of broadband wireless system at a subway. Subway broadband wireless transmission system is tested in this year, and it is to be extended to province subway. Cost of subway broadband wireless transmission system is saved, because the system can be efficiently designed. Therefore, the effectiveness is expected to be very big.

• Journal of Multimedia Information System
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• 제1권1호
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• pp.55-67
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• 2014

Image topic and emotion analysis is an important component of online image retrieval, which nowadays has become very popular in the widely growing social media community. However, due to the gaps between images and texts, there is very limited work in literature to detect one image's Topics and Emotions in a unified framework, although topics and emotions are two levels of semantics that often work together to comprehensively describe one image. In this work, a unified model, Joint Topic/Emotion Multi-Modal Hierarchical Latent Dirichlet Allocation (JTE-MMHLDA) model, which extends previous LDA, mmLDA, and JST model to capture topic and emotion information at the same time from heterogeneous data, is proposed. Specifically, a two level graphical structured model is built to realize sharing topics and emotions among the whole document collection. The experimental results on a Flickr dataset indicate that the proposed model efficiently discovers images' topics and emotions, and significantly outperform the text-only system by 4.4%, vision-only system by 18.1% in topic detection, and outperforms the text-only system by 7.1%, vision-only system by 39.7% in emotion detection.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.564-566
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• 2003

There are no immutable phenomena in reality. A lot of applications are dealing with data characterized by spatial and temporal and/or uncertain features. Currently, there has no any data model accommodating enough those three elements of spatial objects to directly use in application systems. For such reasons, we introduce a fuzzy spatio -temporal data model (FSTDM) and a method of integrating temporal and fuzzy spatial operators in a unified manner to create fuzzy spatio -temporal (FST) operators. With these operators, complex query expression will become concise. Our research is feasible to apply to the management systems and query processor of natural resource data, weather information, graphic information, and so on.