• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권9호
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• pp.2351-2369
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• 2012

This paper describes interpolation method of motion field in the Wyner-Ziv video coding (WZVC) based on Expectation-Maximization (EM) algorithm. In the EM algorithm, the estimated motion field distribution is calculated on a block-by-block basis. Each pixel in the block shares similar probability distribution, producing an undesired blocking artefact on the pixel-based motion field. The proposed interpolation techniques are Bicubic and Lanczos which successively use 16 and 32 neighborhood probability distributions of block-based motion field for one pixel in k-by-k block on pixel-based motion field. EM-based WZVC codec updates the estimated probability distribution on block-based motion field, and interpolates it to pixel resolution. This is required to generate higher-quality soft side information (SI) such that the decoding algorithm is able to make syndrome estimation more quickly. Our experiments showed that the proposed interpolation methods have the capability to reduce EM-based WZVC decoding complexity with small increment of bit rate.

• 인터넷정보학회논문지
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• 제19권2호
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• pp.57-67
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• 2018

The $4^{th}$ industrial revolution has brought innovation in the educational environment. The purpose of this study is to verify the educational effectiveness of smart learning environment especially with the computational thinking. A big data analysis was performed to confirm that computational thinking is the one to prepare the 4th industrial revolution. To teach computational thinking at university, educational design should be careful. This study verified the relationship between improvement of computational thinking ability and major of students with coding education. There was difference in effectiveness of the coding education depending on the major of students, it means students must be guaranteed to be educated by the differentiated coding education for different major. This study extracted factors of computational thinking through literature review. Thirteen research hypotheses were applied for the statistical analysis in R language. It was proved that expectation of class and improvement of abstraction ability and algorithmic thinking ability had mediation effect to the relationship between knowledge acquisition and problem-solving abilities. Based on this study, effectiveness of education can be improved, and it will lead to produce a lot of distinguished students who are ready for the 4th industrial revolution.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권5호
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• pp.1976-1997
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• 2016

This paper investigates the problem of co-tier interference mitigation for dynamic small- cell networks, in which the load of each small-cell varies with the number of active associated small-cell users (SUs). Due to the fact that most small-cell base stations (SBSs) are deployed in an ad-hoc manner, the problem of reducing co-tier interference caused by dynamic loads in a distributed fashion is quite challenging. First, we propose a new distributed channel allocation method for small-cells with dynamic loads and define a dynamic interference graph. Based on this approach, we formulate the problem as a dynamic interference graph game and prove that the game is a potential game and has at least one pure strategy Nash equilibrium (NE) point. Moreover, we show that the best pure strategy NE point minimizes the expectation of the aggregate dynamic co-tier interference in the small-cell network. A distributed dynamic learning algorithm is then designed to achieve NE of the game, in which each SBS is unaware of the probability distributions of its own and other SBSs' dynamic loads. Simulation results show that the proposed approach can mitigate dynamic co-tier interference effectively and significantly outperform random channel selection.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권11호
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• pp.5491-5505
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• 2017

Use of the Gaussian inverse Wishart PHD (GIW-PHD) filter has demonstrated promise as an approach to track an unknown number of extended targets. However, the partitioning approaches used in the GIW-PHD filter, such as distance partition with sub-partition (DP-SP), prediction partition (PP) and expectation maximization partition (EMP), fails to provided accurate partition results when targets are spaced closely together and performing maneuvers. In order to improve the performance of a GIW-PHD filter, this paper presents a cooperation partitioning (CP) algorithm to solve the partitioning issue when targets are spaced closely together. In the GIW-PHD filter, the DP-SP is insensitive to target maneuvers but sensitive to the differences in target sizes, while EMP is the opposite. The proposed CP algorithm is a fusion approach of DP-SP and EMP, which employs EMP as a sub-partition approach after DP. Therefore, the CP algorithm will be sensitive to neither target maneuvers nor differences in target sizes. The simulation results show that the use of the proposed CP algorithm will improve the performance of the GIW-PHD filter when targets are spaced closely together.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.637-640
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• 2011

최근 스마트폰의 급속한 보급에 따라 기지국과 같은 기반구조를 사용하지 않은 MANET(Mobile Ad-Hoc Network)의 활용이 늘어날 것으로 예상되며, 인터넷 전화로 알려진 VoIP는 MANET의 주요 응용서비스 가운데 하나가 될 것으로 생각된다. 한편, 최근 문제점이 심각하게 부각되고 있는 정보침해의 경우, MANET에서도 예외일수는 없다. 특히, 군사적 목적이나 구난 구조와 같은 긴급 목적으로 사용이 가능한 MAENT에 대한 정보침해는 다른 네트워크에 비해 매우 치명적인 결과를 초래할 위험성을 내포하고 있다. 본 논문에서는 이런 문제점을 규명해보고자 블랙홀 공격이 있는 MANET에서 정보침해가 전송성능에 미치는 영향을 분석해 본다. 분석대상 서비스로는 VoIP 트래픽을 가정하였으며, 분석방법으로 NS-2를 사용한 컴퓨터 시뮬레이션을 활용한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권8호
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• pp.4133-4145
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• 2017

Advances in science and technology are driving us to the better life but also forcing us to make more investment at the same time. Therefore, the government has provided the investment to carry on the promising futuristic technology successfully. Indeed, a lot of resources from the government have supported into the science and technology R&D projects for several decades. However, the performance of the public investments remains unclear in many ways, so thus it is required that planning and evaluation about the new investment should be on data driven decision with fact based evidence. In this regard, the government wanted to know the trend and issue of the science and technology with evidences, and has accumulated an amount of database about the science and technology such as research papers, patents, project reports, and R&D information. Nowadays, the database is supporting to various activities such as planning policy, budget allocation, and investment evaluation for the science and technology but the information quality is not reached to the expectation because of limitations of text mining to drill out the information from the unstructured data like the reports and papers. To solve the problem, this study proposes a practical text mining methodology for the science and technology trend analysis, in case of aerospace technology, and conduct text mining methods such as ontology development, topic analysis, network analysis and their visualization.

• 한국인터넷방송통신학회논문지
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• 제18권6호
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• pp.277-283
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• 2018

일부의 혁신적인 사람들은 스스로 생각하는 컴퓨터에 대한 환상을 꿈꾸며, 그 능력을 부여하는 방법을 꾸준히 연구하여왔다. 그런데 알파고의 등장 이후 그 환상이 마냥 허황된 생각만은 아님을 간접적으로 느낄 수 있었고, 이제는 컴퓨터를 전공하는 대부분의 학생들은 그 방법을 공부할 만큼 일반화 되어가고 있다. 딥 러닝에 대한 사람들의 관심이 커지면서 그로 인해 머신러닝에 대한 발전 가능성 또한 많은 사람들이 기대하고 있다. 이번 연구에서는 포커게임을 매개로 하여 머신러닝 기술을 적용하여 시스템의 게임능력을 개선해 보려 하였고, 또한 얼굴 표정에 따른 감정의 변화 분석을 활용하여 게임의 완성도 또한 높여 보았다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권2호
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• pp.912-928
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• 2019

Crowd behavior analysis research has revealed a central role in helping people to find safety hazards or crime optimistic forecast. Thus, it is significant in the future video surveillance systems. Recently, the growing demand for safety monitoring has changed the awareness of video surveillance studies from analysis of individuals behavior to group behavior. Group detection is the process before crowd behavior analysis, which separates scene of individuals in a crowd into respective groups by understanding their complex relations. Most existing studies on group detection are scene-specific. Crowds with various densities, structures, and occlusion of each other are the challenges for group detection in diverse crowded scenes. Therefore, we propose a group detection approach called Collective Interaction Filtering to discover people motion interaction from trajectories. This approach is able to deduce people interaction with the Expectation-Maximization algorithm. The Collective Interaction Filtering approach accurately identifies groups by clustering trajectories in crowds with various densities, structures and occlusion of each other. It also tackles grouping consistency between frames. Experiments on the CUHK Crowd Dataset demonstrate that approach used in this study achieves better than previous methods which leads to latest results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권5호
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• pp.1630-1648
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• 2021

Owing to the unprecedented COVID-19 pandemic, the pharmaceutical industry has attracted considerable attention, spurred by the widespread expectation of vaccine development. In this study, we collect relevant topics from news articles related to COVID-19 and explore their links with two South Korean pharmaceutical indices, the Drug and Medicine index of the Korea Composite Stock Price Index (KOSPI) and the Korean Securities Dealers Automated Quotations (KOSDAQ) Pharmaceutical index. We use generalized Dirichlet-multinomial regression (g-DMR) to reveal the dynamic topic distributions over metadata of index values. The results of our analysis, obtained using g-DMR, reveal that a greater focus on specific news topics has a significant relationship with fluctuations in the indices. We also provide practical and theoretical implications based on this analysis.

• 정보기술응용연구
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• 제3권2호
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• pp.103-132
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• 2001

중소기업의 경쟁력 강화의 한 대안으로서 인터넷 쇼핑몰의 중요성이 대두되고 있다. 본 연구는 중소기업의 인터넷 쇼핑몰에 대한 제반 환경을 체계적으로 조사하여, 중소기업 인터넷 쇼핑몰의 효과적인 운영을 위하여 고려하여야 할 요소들을 분석하는 데 그 주요 목적이 있다. 본 연구를 위해 인터넷 쇼핑몰을 실제로 운영하고 있는 6개 중소기업의 인터뷰를 통해 각 기업의 일반현황, 시스템환경, 진입 및 운영전략, 향후 기업 발전방향 등을 조사하고, 각 기업환경에 따라 구현되고 있는 인터넷 쇼핑몰의 성공 및 실패요인을 분석하여 보았다. 또한 본 연구에서는 쇼핑몰 구축의 2가지 차원 즉, 시스템 구축방법(자체개발/아웃소싱에 의한 개발) 및 쇼핑몰 진입유형(온라인 전문기업/오프라인 확장기업)으로 구분하여, 쇼핑몰 구축환경을 분류하는 맵을 도출하여 대상기업에 대한 추가적인 분석을 시도하여 보았다.