• The Korean Journal of Applied Statistics
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• v.10 no.2
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• pp.309-323
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• 1997

Although there are many photochemical images of which are censored while they are recorded, normal approaches are often applied to the restorations for them. In this case, it yields a restored image which might have serious bias. However, solutions for this problem are hardly found in the research of image restorations. This article provides a method of image restoration via EM algorithm for the censored images of which are contaminated with Gaussian noise and blur, also presents some results of simulation for artificial images censorized.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.5
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• pp.104-111
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• 2002

This paper presents a fuzzy rule extraction method using EM(Expectation-Maximization) algorithm and a design method of adaptive neuro-fuzzy control. EM algorithm is used to estimate a maximum likelihood of a GMM(Gaussian Mixture Model) and cluster centers. The estimated clusters is used to automatically construct the fuzzy rules and membership functions for ANFIS(Adaptive Neuro-Fuzzy Inference System). Finally, we applied the proposed method to the water temperature control system and obtained better results with respect to the number of rules and SAE(Sum of Absolute Error) than previous techniques such as conventional fuzzy controller.

• The Korean Journal of Applied Statistics
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• v.29 no.3
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• pp.513-523
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• 2016

Fitting a mixture of multivariate skew normal distribution (MSNMix) with multiple skewness parameter vectors via EM algorithm often requires a highly expensive computational cost to calculate the moments and probabilities of multivariate truncated normal distribution in E-step. Subsequently, it is common to fit an asymmetric data set with MSNMix with a simple skewness parameter vector since it allows us to compute them in E-step in an univariate manner that guarantees a cheap computational cost. However, the adaptation of a simple skewness parameter is unrealistic in many situations. This paper proposes an approximate estimation for the MSNMix with multiple skewness parameter vectors that also allows us to treat them in an univariate manner. We additionally provide some experiments to show its effectiveness.

• The Korean Journal of Applied Statistics
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• v.23 no.2
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• pp.305-315
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• 2010

In this paper, a frequentistic approach to impute the values of R, G, B-components in random missing pixels of color image is provided. Under assumption that the given image is a realization of Gaussian Markov random field, its model is designed such that each neighbor pixel values for a given pixel follows (independently) the normal distribution with covariance matrix scaled by an evaluates of the similarity between two pixel values, so that the imputation is not to be affected by the neighbors with different color. An approximate EM-based algorithm maximizing the underlying likelihood is implemented to estimate the parameters and to impute the missing pixel values. Some experiments are presented to show its effectiveness through performance comparison with a popular interpolation method.

• Journal of the Korean Society for information Management
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• v.22 no.2 s.56
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• pp.125-145
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• 2005

This paper presents a semantic vector space retrieval model incorporating a word sense disambiguation algorithm in an attempt to improve retrieval effectiveness. Nine Korean homonyms are selected for the sense disambiguation and retrieval experiments. The total of approximately 120,000 news articles comprise the raw test collection and 18 queries including homonyms as query words are used for the retrieval experiments. A Naive Bayes classifier and EM algorithm representing supervised and unsupervised learning algorithms respectively are used for the disambiguation process. The Naive Bayes classifier achieved $92\%$ disambiguation accuracy. while the clustering performance of the EM algorithm is $67\%$ on the average. The retrieval effectiveness of the semantic vector space model incorporating the Naive Bayes classifier showed $39.6\%$ precision achieving about $7.4\%$ improvement. However, the retrieval effectiveness of the EM algorithm-based semantic retrieval is $3\%$ lower than the baseline retrieval without disambiguation. It is worth noting that the performances of disambiguation and retrieval depend on the distribution patterns of homonyms to be disambiguated as well as the characteristics of queries.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.1315-1317
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• 2017

다양한 IoT(사물인터넷) 서비스가 등장하고 수요가 많아짐에 따라 이를 통합적으로 관리하고 제어하는 통합 서비스 플랫폼에 관한 여구가 활발하게 진행되고 있다. 하지만 서비스의 표준 부재로 인하여 IoT 서비스 모듈의 재활용 및 이식은 불가능한 상황이다. 이러한 문제를 해결하기 위하여 본 연구에서는 IoT 서비스의 각 동작 단계에 EM 알고리즘을 적용하여 [1]의 동작기반 분류 기법을 확장한다. 제안한 EM 기반 IoT 서비스 분류 알고리즘은 서비스 유사도를 기반하여 분류 함으로 모듈의 재활용성을 높이고 서비스 간의 협업에 있어서 효율성 증대를 기대할 수 있다. 성능 평가를 통하여 평균에 대한 표준편차로 클러스터링되는 것을 확인 할 수 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.790-792
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• 2004

문서 범주화에서 이진분류를 다중 분류에 적용할 때, 일반적으로 One-Against-All 방법을 사용한다. 하지만, 이 One-Against-All 방법은 한가지 문제점을 가진다. 즉, positive 집합의 문서들은 사람이 직접 범주를 할당한 것이지만, negative 집합의 문서들은 사람이 직접 범주를 할당한 것이 아니기 때문에 오류 문서들이 포함될 수 있다는 것이다. 본 논문에서는 이러한 문제점을 해결하기 위해 Sliding Window기법과 EM 알고리즘을 이진 분류 기반의 문서 범주화에 적용할 것을 제안한다. 먼저 Sliding Window 기법을 이용하여 학습 데이터로부터 오류 문서들을 추출하고 이 문서들을 EM 알고리즘을 사용해서 다시 범주를 할당함으로써 이진 분류 기반의 문서 범주화 기법의 성능을 향상시킨다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.1307-1310
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• 2008

EM(Expectation Maximization)은 불확실한 데이터들을 가지고 분포를 모델링하는, 널리 알려진 군집화 알고리즘이다. EM 알고리즘에서, 정규 분포는 기대(Expectation)-최대화(Maximization)과정을 반복하는 과정에서 그 윤곽을 다져간다. 이 때 이 과정은 EM 알고리즘의 다양한 확률 초기화에 따라 다른 결과를 내게 된다, 본 논문에서는 이 확률 초기화 값의 조정을 통하여 HAPS(High Altitude Platform Station) 기반 네트워크에서 이동 기지국의 위치를 실시간으로 결정하고자 하는 문제를 풀기 위한 조건을 몇 가지 반영시켜 확률 초기 값을 결정해 보고, 그 결과를 제시한다. 이에 더불어, ITU에서 제한하고 있는 이동 기지국의 서비스 반경을 고려하는 방법을 제시한다.

• Journal of Service Research and Studies
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• v.5 no.2
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• pp.25-33
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• 2015

As Data mining is a method of extracting the information based on the large data, the technique has been used in many application areas to deal with data in particular. However, the status of the algorithm that can deal with the healthcare data are not fully developed. In this paper, One of clustering algorithm, the EM and DBSCAN are used for performance comparison. It could be analyzed using by the same data. To do this, EM and DBSACN algorithm are changing performance according to the variables in Health expenditure database. Based on the results of the experimental data, We analyze more precise and accurate results using by Kernel Filtering. In this study, we tried comparison of the performance for the algorithm as well as attempt to improve the performance. Through this work, we were analyzed the comparison result of the application of the experimental data and of performance change according to expansion algorithm. Especially, Collects data from the various cluster using the medical record, it could be recommended the effective spending on medical services.

• Journal of the Korean Data and Information Science Society
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• v.7 no.2
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• pp.247-256
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• 1996

In this paper, we applied bayesian hierarchical model to analyze the field mice example introduced by Demster et al.(1981). For this example, we use Gibbs sampler method to provide the posterior mean and compared it with LSE(Least Square Estimator) and MLR(Maximum Likelihood estimator with Random effect) via the EM algorithm.