• The Korean Journal of Applied Statistics
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• v.6 no.2
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• pp.409-419
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• 1993

This paper concerns graphical methods for discriminant analysis. We discuss Sammon's graph, MV graph and possibility of an alternative. The properties of the three graphs are investigated using real data and simulation studies. Dimensionality reduction for an alternative and robust procedure are discussed.

• The Korean Journal of Applied Statistics
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• v.27 no.3
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• pp.487-500
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• 2014

The elementary school curriculum includes some statistical concepts and many graphical methods. However, statistical concepts are difficult to understand; consequently, many of those graphs and numerical summaries are obtained by hand. We develop an intuitive statistics education package called Tong-Gramy focused on 5-8 graders to help students and teachers study statistics. This software covers numerical and graphical statistics that appear in 5-8 graders' textbooks. The graphs provided are dynamically linked to data and every graph is linked to every datum. The graphs of Tong-Gramy are dynamic graphs and morphing technology is used where applicable.

• Journal of the Korean Data and Information Science Society
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• v.22 no.1
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• pp.99-105
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• 2011

We propose a semi-supervised learning algorithm based on a form of regularization that incorporates similarity and dissimilarity penalty terms. Our approach uses a graph-based encoding of similarity and dissimilarity. We also present a model-selection method which employs cross-validation techniques to choose hyperparameters which affect the performance of the proposed method. Simulations using two types of dat sets demonstrate that the proposed method is promising.

• Journal of Biomedical Engineering Research
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• v.10 no.3
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• pp.317-322
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• 1989

In this paper, brain CT images are automatically segmented to reconstruct the 3-D scene from consecutive CT sections. Contextual segmentation technique was applied to overcome the partial volume artifact and statistical fluctuation phenomenon of soft tissue images. Images are hierarchically analyzed by region growing and graph editing techniques. Segmented regions are discriptively decided to the final organs by using the semantic informations.

• The Journal of the Korea Contents Association
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• v.19 no.1
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• pp.141-151
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• 2019

A network of graph data structure is used in many applications to represent interactions between entities. Recently, as the size of the network to be processed due to the development of the big data technology is getting larger, it becomes more difficult to handle it in one server, and thus the necessity of distributed processing is also increasing. In this paper, we propose a distributed processing system for efficiently performing subgraph and stores. To reduce unnecessary searches, we use statistical information of the data to determine the search order through probabilistic scoring. Since the relationship between the vertex and the degree of the graph network may show different characteristics depending on the type of data, the search order is determined by calculating a score to reduce unnecessary search through a different scoring method for a graph having various distribution characteristics. The graph is sequentially searched in the distributed servers according to the determined order. In order to demonstrate the superiority of the proposed method, performance comparison with the existing method was performed. As a result, the search time is improved by about 3 ~ 10% compared with the existing method.

• Education of Primary School Mathematics
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• v.21 no.4
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• pp.397-413
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• 2018

The purpose of this study is to analyze the level of statistical literacy among fifth and sixth graders in the data presentation task based on the speculative data generation process. For the research, the data presentation tasks based on the speculative data generation process was designed and statistical literacy standards for evaluating the student's level was presented based on prior studies. It is meaningful that the stepwise presentation of the students' statistical literacy and analysis of their developmental patterns can help them to find their current position and reach a higher level of performance. In this study, the standard of statistical literacy level was clarified based on the previous research, and a new perspective was presented about the data presentation instruction in the statistical education by analyzing the students' responses by each level.

• Proceedings of the Korean Statistical Society Conference
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• 2003.05a
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• pp.157-162
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• 2003

Estimates from an EM algorithm are somewhat sensitive to the initial values for the estimates, and it is more likely when the model becomes larger and more complicated. In this article, we examined how the estimates fluctuate during an EM procedure for a recursive model of categorical variables. It is found that the fluctuation takes place mostly during the first half of the procedure and that it can be subdued by applying the Bayesian method of estimation. Both simulation data and real data are used for illustration.

• Communications for Statistical Applications and Methods
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• v.7 no.3
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• pp.741-757
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• 2000

In may experimental situations, whenever a block design is used, the block effect is usually considered to be fixed. There are, however, experimental situations in which it should be treated as random. The choice of a blocking arrangement for a response surface design can have a considerable effect on estimating the mean response and on the size of he prediction variance even if the experimental runs re the same. Therefore, care should be exercised in the selection of blocks. In this paper, in the presence of a random block effect, we propose a graphical method or evaluating the effect of blocking in response surface designs using cuboidal regions. This graphical method can be used to investigate how the blocking has influence on the prediction variance throughout all experimental regions of interest when this region is cuboidal, and compare the block effects in the cases of the orthogonal and non-orthogonal block designs, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.923-931
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• 2017

A power grid is one of the most complex networks and is critical infrastructure for society. To understand the characteristics of a power grid, complex network analysis has been used from the early 2000s mainly for US and European power grids. However, since the power grids of different countries might have different structures, the Korean power grid needs to be examined through complex network analysis. This paper performs the analysis for the Korean power grid, especially for high-voltage transmission networks. In addition, statistical and small-world characteristics for the Korean power grid are analyzed. Generally, the Korean power grid has similar characteristics to other power grids, but some characteristics differ because the Korean power grid is concentrated in the capital area.

• Proceedings of the Korean Reliability Society Conference
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• 2000.04a
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• pp.123-129
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• 2000

SPC is the quality improvement technique of gathering since Motorola of U.S.A. have used SPC technique as a statistical process control method for promoting 6-sigma quality improvement strategy in 1988. In Korea, small and medium-sized enterprises are needed building of a system for statistical production control . In the present study, the methods of building SPC system with a moderate cost using a graphic programs of easy-to-use and high flexibility for small and medium-sized enterprises were inquired. The SPC system which enables statistic marking (maximum, minimum, mean, standard deviation, process capability index) and graph marking (X-Y coordinates and histogram) using LabVIEW 5.0, the graphic program by National Instrument Co., Ltd. was implemented in this study.