• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.193-200
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• 2007

The objective of this study was to estimate uncertainty of online TOC analyzer in water quality monitoring system. A procedure for the estimation of measurement uncertainty of total organic compounds (TOC) based on the ISO approach is presented. It is based on a mathematical model that involves 4 input parameters (standardization, sensitivity, solute effect and representativeness). In this study, a major problem in estimating the uncertainty of online TOC analyzer was the solute effect. It was strongly depends on organic materials. So homogeneity of the sample is the most important consideration. Modified concentration and combined standard uncertainty was $4.71{\pm}0.36$ mg $L^{-1}$ by model modified in this study.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.8
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• pp.939-948
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• 1999

주문형 비디오나 원격 회의 그리고 원격 강의와 같은 멀티미디어 애플리케이션들은 비디오나 오디오와 같은 멀티미디어 트래픽을 유발한다. 이러한 멀티미디어 트래픽의 가장 큰 특성은 폭주성이다. 폭주성은 통신망의 효율을 떨어뜨리는 매우 중요한 요인이며, 따라서 폭주성에 대처할 수 있는 효율적인 대역폭 할당 정책이 통신망 관리에서 매우 중요하다. 본 논문에서는 멀티캐스팅 방식의 온라인 비디오 애플리케이션에 대해서 대역폭 완화 작업이라고 불리우는 효율적이고 유용한 대역폭 할당 방안을 설계하였다. 본 논문에서 제시하는 새로운 대역폭 완화 기법은 비디오 서버에서 이미 전송된 데이타의 특성을 이용하여 대역폭 완화창의 크기를 조절하는 동적인 기법이다. 몇 가지 MPEG 트레이스들로 실험했을 때 기존의 온라인 대역폭 완화 기법과 비슷한 성능을 보이고, 특히 멀티캐스팅 방식의 온라인 비디오 서비스에 대해서는 서버의 자원 효율성을 향상시킴을 알 수 있었다. Abstract All of the multimedia applications such as VOD, teleconferencing, and tele-lecturing invoke multimedia traffic like video or audio traffic. The most important characteristic of these multimedia traffic is the burstiness property. So, bandwidth management is becoming the major part of network management. In this paper, we propose a new and efficient bandwidth management technique called bandwidth smoothing for the multicasting on-line video applications. Our bandwidth smoothing technique reduces as much of the network bandwidth required to transmit on-line video traffic as previously proposed methods, and improves the server's resource utilization especially for the multicast on-line video services.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.8
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• pp.39-47
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• 1999

This paper describes on-line retrainable RBF network in order to control the coiling temperature for a hot coil strip at Pohang Iron & Steel Company(POSCO). The proposed neural network can be used for improving conventional rule-based lookup table, which generates a heat transmission coefficient. To cope with time-varying characteristics of hot coil process, additional synaptic weights for on-line retraining purposes are introduced to hidden-to-output weights of conventional RBF network. Those weights are locally adjusted to newly incoming test data while preserving old information trained with off-line past data. Hence the effect of catastrophic interference can be greatly alleviated with the proposed network. In addition, rejection scheme is introduced for reliability concerns. From the experimental results applied to the actual process, it is noticed that overall control performance represents about 2.2% increase compared to the conventional one.

• Journal of the Korean Data and Information Science Society
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• v.28 no.6
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• pp.1245-1255
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• 2017

The online learning is a process of obtaining the solution for a given objective function where the data is accumulated in real time or in batch units. The stochastic gradient descent method is one of the most widely used for the online learning. This method is not only easy to implement, but also has good properties of the solution under the assumption that the generating model of data is homogeneous. However, the stochastic gradient method could severely mislead the online-learning when the homogeneity is actually violated. We assume that there are two heterogeneous generating models in the observation, and propose the a new stochastic gradient method that mitigate the problem of the heterogeneous models. We introduce a robust mini-batch optimization method using statistical tests and investigate the convergence radius of the solution in the proposed method. Moreover, the theoretical results are confirmed by the numerical simulations.

• The Journal of the Korea Contents Association
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• v.19 no.12
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• pp.57-67
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• 2019

The way people read news is changing, from print to screen. In this study, we aimed to understand the impact of the use of infographics in news on readers. According to a study conducted by Reuters Research Institute at the University of Oxford in 2017, the proportion of online consumers of news is steadily increasing, with over 51 per cent of Americans receiving news via social media. Additionally, newspaper subscription rates are rapidly declining. According to previous studies, the understanding of text information is higher in print media than on screen. Therefore, to compensate for the weaknesses in the understanding of online news, online news media are providing infographic news services to deliver good news. Therefore, this study attempted to understand the impact of using infographics in the news. To this end, three experiments were conducted. The findings from the study indicate that the use of infographics in news has a positive effect on users in terms of the variables measured, including cognitive effect and acceptance of news. As compared with print news, on-screen news was not as effective in terms of comprehension. However, we propose interactive infographics to enhance communication effect along with improved design.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.11
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• pp.479-486
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• 2015

Model checking method is able to check all possible cases automatically and is applicable to specifications or design before actual implementation so that some critical systems have adopted this method actively. However, the current practice of software verification is largely dependant on basic methods such as manual testing because of lack of understanding about this rigorous method and high verification cost. In this paper we conducted an experimental research for the automated verification using the SPIN model checker on an online-game server to study the applicability of the technique in this domain. The results show that we could verify major features of the online-game server party system with 5~7 GB memory and within 10 minutes execution time, and also found a hidden system error that passed existing testing process. This result shows the possibility of rigorous and effective verification with reasonable cost in comparison to manual testing.

• Journal of Creative Information Culture
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• v.6 no.3
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• pp.169-177
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• 2020

In this study, the satisfaction level of the class between 'Content utilization and task performance class' and 'real-time interactive class' was compared and analyzed among the types of online classes conducted in elementary schools. The researchers conducted a study to compare and analyze the satisfaction level of classes in 'Content utilization and task performance class' and 'Real-time interactive class', and the research group selected 98 elementary school students in Hwaseong. As a result of the analysis, the satisfaction level of classes for "real-time interactive classes" was high. The satisfaction level of students' characteristics was analyzed, students who were not good at performing their task and those who were not good at concentrating on their classes were more satisfied with 'content utilization and task performance classes.'

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.295-297
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• 2021

In this study, the difference in resilience was analyzed based on the results of the microprocessor class for the group who temporarily conducted online learning due to COVID-19 and made a cross-school course. As a result of the study, the resilience value in online learning was found to be less than 150 in 12, 150 to less than 180 in 33, and 180 or more in 10. On the other hand, the resilience value in offline learning was found to be less than 150, 8 people, 150 or more, 180, 30, 180 or more, 17. Therefore, in subjects that teach hardware and software at the same time, such as a microprocessor, it is necessary to proceed with offline learning that can establish a laboratory learning environment, and when proceeding with online learning unavoidably due to COVID-19, the theory is the same as other theoretical subjects. Content should be focused on.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.508-510
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• 2021

In this study, the difference in resilience was analyzed based on the results of a study of classes that practiced using Raspberry Pi, which had to cross school due to temporarily conducting online classes due to the COVID-19 pandemic. As a result of the study, in online classes, 14 people had resilience less than 150, 32 people who had 150 or more and less than 180, and 9 people who had 180 or more. On the other hand, in the school attendance class, there were 7 people with resilience less than 150, 29 people with resilience less than 150 and less than 180, and 20 people with more than 180. Therefore, in subjects where programming using Raspberry Pi and circuit manufacturing are taught at the same time, the laboratory and practice environment should be able to proceed properly as much as possible. should proceed mainly.

• Journal of Korea Multimedia Society
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• v.8 no.3
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• pp.297-312
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• 2005

Aggregation is an operation that plays a key role in multidimensional OLAP (MOLAP) systems of data warehouse. Existing aggregation operations in MOLAP have been proposed for file structures such as multidimensional arrays. These tile structures do not work well with skewed distributions. This paper presents a physical design methodology for storage structures ni MOLAP that use the multidimensional tile organizations adapting to a skewed distribution. In uniform data distribution, we first show that the performance of multidimensional analytical processing is highly affected by the similarity of the shapes between query regions and page regions in the domain space of the multidimensional file organizations. And than, in skewed distributions, we reflect the effect of data distributions on the design by using the shapes of the normalized query regions that are weighted with data density of those query regions. Finally, we demonstrate that the physical design methodology theoretically derived is indeed correct in real environments. In the two-dimensional file organizations, the results of experiments indicate that the performance of the proposed method is enhanced by more than seven times over the conventional method. We expect that the performance will be more enhanced when the dimensionality is more than two. The result confirms that the proposed physical design methodology is useful in a practical way.