• Journal of Korea Multimedia Society
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• v.19 no.7
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• pp.1107-1115
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• 2016

Efficient Market Hypothesis (EMH), states that at any point in time in a liquid market security prices fully reflect all available information. This paper presents a study of proving the hypothesis through daily Twitter sentiments using the hybrid approach of the lexicon-based approach and the naïve Bayes classifier. In this research we analyze the currency exchange rate movement of Indonesia Rupiah vs US dollar as a way of testing the Efficient Market Hypothesis. In order to find a correlation between the prediction sentiments from Twitter data and the actual currency exchange rate trends we collect Twitter data every day and compute the overall sentiment to label them as positive or negative. Experimental results have shown 69% correct prediction of sentiment analysis and 65.7% correlation with positive sentiments. This implies that EMH is semi-strong Efficient Market Hypothesis, and that public information provide by Twitter sentiment correlate with changes in the exchange market trends.

• Journal of Korea Multimedia Society
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• v.23 no.2
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• pp.368-375
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• 2020

In this study, the area of interest(AOI) of Soju ad poster was tracked for analysis the time to frist fixation, the average of fixation duration and count by the study indexes. As a result of the analysis, Visual attention was higher the face than the body shape of the ad model. This means "when we look at printed ads, we see picture elements first, not language one" but language elements can't be overlooked either. Also, the importance of the model role could be verified by measuring the visual attention on the Soju ad poster. Based on the results of this study, if further research on ad posters is carried out and scientific and quantitative interpretation methods are presented, it can be used as product marketing data that can be reflected in ad model selection and poster design.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.10
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• pp.2429-2440
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• 2015

This paper introduces an online collaboration infrastructure in order to build a nationwide collaboration ecosystem in research and education areas. The proposed infrastructure involves domestic research institutes, education institutions and related commercial service vendors. It also includes various systems and services which can promote their online collaboration. Especially it provides the user authentication framework based on identity federation which facilitates the share of various ICT resources across different organizations, thereby enabling the efficient R&D collaboration. We deploy and validate the user authentication framework of the infrastructure on KREONET.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.487-490
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• 2012

Under the situation of the world becoming a unified global economy, our country should make efforts to get standard patents as well as to take out essential patents in order to maintain the competitiveness against advanced country. In recent years, R&D related standardization is very important. Besides, R&D planning considering standardization becomes more important than ever before. Therefore, this treatise is designed to lay infrastructure on promoting international standardization through suggesting a effective standardization planning framework based on R&D planning and analyzing cases regarding R&D planning and standardization planning.

• Annual Conference of KIPS
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• 2016.10a
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• pp.651-652
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• 2016

최근 스포츠 과학과 ICT 기술을 접목하여 스포츠 활동올 분석하고자 하는 시도가 증가하고 있다. 이런 양상은 축구 경기에 대한 분석에서도 나타나고 있으며, 그 목적에 따라 다양한 방법으로 분석을 시도한 사례를 쉽게 발견 할 수 있다. 하지만, 현재까지 제시된 시스템들은 높은 수준의 경기 내용 분석올 제공하려는 시도를 보이지 않고 있다. 본 논문은 통계 분석 위주의 현재 축구 분석 시스템의 한계에 대해 논한 후 이를 내용 이해 기반으로 끌어올리기 위한 시스템의 구성 방법에 대한 구체적인 안을 제시하였다. 제안하는 시스템의 개발을 통하여 새로운 양상의 서비스와 산업 생태계 측면의 긍정적 변화를 기대할 수 있다.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.4
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• pp.336-344
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• 2017

This paper presents the three-port DC-DC converter modeling and controller design procedure, which is part of the solid-state transformer (SST) to interface medium voltage AC grid to bipolar DC distribution network. Due to the high primary side DC link voltage, the proposed converter employs the three-level neutral point clamped (NPC) topology at the primary side and 2-two level half bridge circuits for each DC distribution network. For the proposed converter particular structure, this paper conducts modeling the three winding transformer and the power transfer between each port. A decoupling method is adopted to simplify the power transfer model. The voltage controller design procedure is presented. In addition, the output current sharing controller is employed for current balancing between the parallel-connected secondary output ports. The proposed circuit and controller performance are verified by experimental results using a 30 kW prototype SST system.

• Journal of Information Processing Systems
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• v.10 no.3
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• pp.355-364
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• 2014

Internet accessibility has been growing due to the diffusion of smartphones in today's society. Therefore, people can generate data anywhere and are confronted with the challenge that they should process a large amount of data. Since the appearance of relational database management system (RDBMS), most of the recent information systems are built by utilizing it. RDBMS uses foreign-keys to avoid data duplication. The transactions in the database use attributes, such as atomicity, consistency, isolation, durability (ACID), which ensures that data integrity and processing results are stably managed. The characteristic of RDBMS is that there is high data reliability. However, this results in performance degradation. Meanwhile, from among these information systems, some systems only require high-performance rather than high reliability. In this case, if we only consider performance, the use of NoSQL provides many advantages. It is possible to reduce the maintenance cost of the information system that continues to increase in the use of open source software based NoSQL. And has a huge advantage that is easy to use NoSQL. Therefore, in this study, we prove that the leverage of NoSQL will ensure high performance than RDBMS by applying NoSQL to database systems that implement RDBMS.

• Communications for Statistical Applications and Methods
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• v.21 no.6
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• pp.487-500
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• 2014

A new method to calculate the transmittable prevalence of an epidemic disease is proposed based on a back-calculation formula. We calculated the probabilities of reactivation and of parasitemia as well as transmittable prevalence (the number of persons with parasitemia in the incubation period) of malaria in South Korea using incidence of 12 years(2001-2012). For this computation, a new probability function of transmittable condition is obtained. The probability of reactivation is estimated by the least squares method for the back-calculated longterm incubation period. The probability of parasitemia is calculated by a convolution of the survival function of the short-term incubation function and the probability of reactivation. Transmittable prevalence is computed by a convolution of the infected numbers and the probabilities of transmission. Confidence intervals are calculated using the parametric bootstrap method. The method proposed is applicable to other epidemic diseases in other countries where incidence and a long incubation period are available. We found the estimated transmittable prevalence in South Korea was concentrated in the summer with 276 cases on a peak at the $31^{st}$ week and with about a 60% reduction in the peak from the naive prevalence. The statistics of transmittable prevalence can be used for malaria prevention programs and to select blood transfusion donors.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.6
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• pp.591-597
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• 2014

A wide variety of image application methods, such as aerial image, terrestrial image, terrestrial laser, and stereo image point are currently under investigation to develop three-dimensional 3D geospatial information. In this study, matching points, which are needed to build a 3D model, were examined under diverse weather conditions by analyzing the stereo images recorded by closed circuit television (CCTV) cameras installed in the U-City. The tests on illuminance and precipitation conditions showed that the changes in the number of matching points were very sensitively correlated with the changes in the illuminance levels. Based on the performances of the CCTV cameras used in the test, this study was able to identify the optimal values of the shutter speed and iris. As a result, compared to an automatic control mode, improved matching points may be obtained for images filmed using the data obtained through this test in relation to different weather and illuminance conditions.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.668-676
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• 2016

The accelerated convergence of automobiles and ICT has led to an increase in in-vehicle electronic devices designed to enhance the safety and convenience of drivers. Consequently, the information presentation on in-vehicle display systems for drivers and passengers need to be taken into account in order to guarantee driving stability while satisfying the needs of UX-based design users. This study compared and evaluated requirements for information items shown on in-vehicle displays regarding driving safety and convenience by groups according to driving career. A total of 38 information items related to safety and convenience that can be displayed while driving and pulling over were collected. Their level of necessity was tested and evaluated by 234 drivers. Using the results, we conducted a comparative analysis on the requirements for information presentation on in-vehicle display systems by groups according to driving career.