• Journal of the Korean Statistical Society
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• v.10
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• pp.140-144
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• 1981

This paper approximates to a kernel density estimate by a truncated series of expansion involving Hermite polynomials, since this could ease the computing burden involved in the kernel-based density estimation. However, this truncated series may give a multimodal estimate when we are estiamting unimodal density. In this paper we will show a way to insure the truncated series to be positive and unimodal so that the approximation to a kernel density estimator would be maeningful.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.8
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• pp.878-882
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• 2010

DaaS model that surrogates their data has a problem of privacy leakage by service provider. In this paper, we analyze inference attack that can occur on encrypted data that consist of multiple column through index, and we suggest b-anonymity to protect data against inference attack. We use R+-tree technique to minimize false-positive that can happen when we use an index for efficiency of data processing.

• Journal of Internet Computing and Services
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• v.19 no.5
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• pp.115-122
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• 2018

This study examined the relationship between SNS use and individual psychological well-being on Instagram. In particular, this study sorted three types of perceived social support-informational, companionship, and self-esteem-to investigate how they influenced individual life satisfaction and loneliness. Results from a survey of 174 college students showed that: (1) frequency of Instagram use was a significant predictor of all three types of perceived social support; (2) status updates had positive effects on perceived self-esteem support, while posting photos was a significant predictor of perceived companionship support; (3) browsing others' profiles was a significant negative predictor of perceived self-esteem support and finally (4) perceived companionship social support had a positive effect on life satisfaction, whereas self-esteem social support had a negative effect on loneliness. These findings imply that Instagram users obtain specific types of social support depending on which activities they engage in and that different types of social support have different effects on well-being.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.25 no.4
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• pp.162-172
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• 2021

This paper proposes stochastic methods to find an approximate solution for the L²-Wasserstein least squares problem of Gaussian measures. The variable for the problem is in a set of positive definite matrices. The first proposed stochastic method is a type of classical stochastic gradient methods combined with projection and the second one is a type of variance reduced methods with projection. Their global convergence are analyzed by using the framework of proximal stochastic gradient methods. The convergence of the classical stochastic gradient method combined with projection is established by using diminishing learning rate rule in which the learning rate decreases as the epoch increases but that of the variance reduced method with projection can be established by using constant learning rate. The numerical results show that the present algorithms with a proper learning rate outperforms a gradient projection method.

• Journal of Internet Computing and Services
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• v.20 no.3
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• pp.93-100
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• 2019

The interest in the Fourth Industrial Revolution along with the development of ICT makes the software get the attention of the world. This phenomenon naturally leads to the concern for software education. Learning software coding is not easy for students whose major is in humanities or social sciences. This paper is a study of how cognition on software education affects to education of computational thinking. For research method, moderator variables were adopted on the proposed research model to prove that positive cognition can derive good influence on improvement of computational thinking. To find out moderator variables of the research model, we have conducted the questionnaire over three years for total of 928 students who took the software coding courses. As the result of the study, we proved that the positive cognition on software education can make the better improvement of computational thinking within proper moderator variables.

• Educational Technology International
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• v.16 no.1
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• pp.31-57
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• 2015

This study aims to understand the overall experiences of students who use notebook computers in class by using a qualitative approach. Interview data were collected from 23 Korean college students at a Korean university, who use notebook computers in their classes; the data were analyzed through the constant comparison method. The results from this study can be categorized into two themes: the positive and negative effects of using a notebook computer in class, and different perspectives on the effects of using a notebook computer in class. The positive effects of notebook computer usage were specified as production of lecture notes, performing searches for information, management of learning materials, and effective time management. However, behaviors such as perusing other works not associated with the class were indicated as negative effects. The participants had different perceptions about the effect of notebook computer usage in increasing academic performance, although they were satisfied in their experience with notebook computers in general. These results imply that appropriate methods of technology usage are needed and that the support of an instructor is essential to achieve fully beneficial use of notebook computers in class.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.3
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• pp.163-168
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• 2015

Many IP address lookup approaches employ Bloom filters to obtain a high-speed search performance. Especially, it has been recently studied that the search performance of trie-based algorithms can be significantly improved by adding Bloom filters. In such algorithms, the number of trie accesses can be greatly reduced because Bloom filters can determine whether a node exists in a trie without actually accessing the trie. Bloom filters do not have false negatives but have false positives. False positives can lead to unnecessary trie accesses. The false positive rate must thus be reduced to enhance the performance of lookup algorithms applying Bloom filters. One important characteristic of trie-based algorithms is that all the ancestors of a node are also stored. The proposed algorithm utilizes this characteristic in reducing the false positive rate of a Bloom filter without increasing the size of the memory for the Bloom filter. When a Bloom filter produces a positive result for a node of a trie, we propose to check whether the ancestors of the node are also positives. Because Bloom filters have no false negatives, the negatives of any of the ancestors mean that the positive of the node is false. In other words, we propose to use more Bloom filter queries to reduce the false positive rate of a Bloom filter in trie-based algorithms. Simulation results show that querying one ancestor of a node can reduce the false positive rate by up to 67% with exactly the same architecture and the same memory requirement. The proposed approach can be applied to other trie-based algorithms employing Bloom filters.

• Journal of Internet Computing and Services
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• v.8 no.2
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• pp.89-94
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• 2007

Even though lots of research have been doing about spam mail blocking technologies and their systems, the emergence of spam mails of new types causes the spam mail filtering rate to decrease and the occurrences of false-positive mails to increase. Therefore, existing spam mail filtering algorithms suffer from increasing load to be processed and decreasing reliability in spam mail blocking systems due to the shortage of newly developed algorithms and their research. This paper presents the Fit-FA Finder which is able to select appropriate algorithms to be applied and their procedures, and the development of the SMBC platform. The Fit-FA Finder is developed and implemented in the SMBC platform in which recovering process based on privacy information is employed for false-positive mails

• Journal of Internet Computing and Services
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• v.20 no.1
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• pp.113-124
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• 2019

Recently, Omni Channel Services has been considered the most innovative business strategy. Omni-Channel sees a variety of channels from all channels viewpoints, organically combining each channel to provide a seamless experience for consumers. In other words, Omni-Channel is not simply a systematic integration of channels, but a means of delivering consistent services to consumers in all processes through a strategy to an organic connection. The aim of this study is to provide a comprehensive insight into the decision factors affecting the adoption of Omni-channel. For this purpose, an empirical analysis is conducted on the course of acceptanceof the Omni-channel service based on the Unified Theory of Acceptance and Use of Technology (UTAUT) and Task-technology fit (TTF), an effective model frequently selected to describe the acceptance of service in the introduction phase of new information technology. As a result of the study, it was confirmed that the task characteristics and the technical characteristics had a positive effect on the task-technology fit, and the task-technology fit had a positive effect on the performance expectancy. In addition, task-technology fit, performance expectancy, and social influence have a positive effect on the intention to use the Omni-Channel. This study is intended to deliver an experimental meaning by proposing a strategical measure to understand the behaviorsand uses of consumers in the Omni-channel service environment and increase the customer satisfaction for the system.

• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.179-192
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• 2018

The purpose of this study is to research the design solutions that should be taken into consideration when developing mobile applications of Mindfulness Training. We aim to provide basic UI / UX design guidances for being effectiveness of mobile application of Mindfulness Training. For this purpose, We research in various aspects. Base on this, We select an approach and apply the application screen prototypes. We suggest some points for to be considered in the development of UI / IX design for mobile applications for Mindfulness Training based on obtained knowledge through this research process.