• Journal of Korean Society of Environmental Engineers
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• v.30 no.2
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• pp.199-206
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• 2008

Simultaneous nitrification and denitrification means that nitrification and denitrification occur concurrently in the same reaction vessel under low DO concentration. Some mathematical models developed to simulate simultaneous nitrification and denitrification reaction, but they have the complex model structures or have limitations of model application. To solve these problems, if possible that predict the behavior of simultaneous nitrification and denitrification reaction by activated sludge model, structures of the model is less complex than previous models and applies the various operation conditions. But original activated sludge models have difficulties in representing the denitrification reaction under aerobic condition. So the aim of this study is to interpret simultaneous nitrification and denitrification reaction by modifying activated sludge model. Original activated sludge model No.1(ASM1) was selected and modified. The simulation result in modified ASM1 predicted appropriately for the measured data. This indicates the structures of ASM1 are properly improved for interpretation of simultaneous nitrification and denitrification reaction.

• The Journal of the Korea Contents Association
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• v.17 no.7
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• pp.113-123
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• 2017

This research is designed to review the systems thinking and STEAM theory while ascertaining the effects of the classroom application of the STEAM programs based on systems thinking appropriate for studying climate change. The systems thinking based STEAM program has been developed by researchers and experts, who had participated in expert meetings in a continued manner. The program was applied to science classes over the course of eight weeks. Therefore, the application effects of the systems thinking based STEAM program were analyzed in students' systems thinking, STEAM semantics survey, and students' academic achievement. The findings are as follows. First, the test group has shown a statistically meaningful difference in the systems thinking analysis compared to the control group in the four subcategories of 'Systems Analysis', 'Personal Mastery', 'Shared Vision' and 'Team Learning' except for 'Mental Model'. Second, in the pre- and post-knowledge tests, the independent sample t-test results in the areas of science, technology, engineering, art and mathematics show statistically meaningful differences compared to the control group. Third, in the academic performance test regarding climate change, the test group displayed higher achievement than the control group. In conclusion, the system-based STEAM program is considered appropriate to enhance amalgamative thinking skills based on systems thinking. In addition, the program is expected to improve creative thinking and problem-solving abilities by offering new ideas based on climate change science.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.3
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• pp.57-67
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• 2007

Researchers in mobile AR systems have so far put the value on the technical challenges involved in the limitations imposed from mobility. Beyond such immediate technical questions, however, are questions regarding the possible contents that are to be used for the user’s interaction in ubiquitous computing environment. Various aspects of context of user and environment can be utilized easily as well as effectively. Moreover, the environment will be equipped with lots of pervasive but invisible computing resources. However, it is difficult for users to have access to those computing resources. At the same time, as the smart appliances get to have more features, their user interfaces tend to become harder to use. Thus, in this paper, we propose Context-Aware Mobile Augmented Reality (CAMAR) system. In our system, users only need to take a picture of smart appliances with a built-in camera in a mobile device when they intend to control the appliances. It lets users interact with the smart appliances through personalized control interfaces on their mobile devices. Also, it supports enabling contents to be not only personalized but also shared selectively and interactively among user communities.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.164-173
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• 2014

In underwater robotics, vision would be a key element for recognition in underwater environments. However, due to turbidity an underwater optical camera is rarely available. An underwater imaging sonar, as an alternative, delivers low quality sonar images which are not stable and accurate enough to find out natural objects by image processing. For this, artificial landmarks based on the characteristics of ultrasonic waves and their recognition method by a shape matrix transformation were proposed and were proven in Part 1. But, this is not working properly in undulating and dynamically noisy sea-bottom. To solve this, we propose a framework providing a selection phase of likelihood candidates, a selection phase for final candidates, recognition phase and tracking phase in sequence images, where a particle filter based selection mechanism to eliminate fake candidates and a mean shift based tracking algorithm are also proposed. All 4 steps are running in parallel and real-time processing. The proposed framework is flexible to add and to modify internal algorithms. A pool test and sea trial are carried out to prove the performance, and detail analysis of experimental results are done. Information is obtained from tracking phase such as relative distance, bearing will be expected to be used for control and navigation of underwater robots.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.2
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• pp.65-73
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• 2008

The characterization process for the accurate color reproduction in mobile phone with camera and LCD is popular. The camera and LCD characterization, gamut mapping process is necessary to map the camera's input color stimulus, CIEXYZ value, into the LCD's output color stimulus. Each characterization is the process estimating the relation between input and output signals. In case of LCD, because of output device, the output color stimulus for the arbitrary input signal can be measured by spectro-radiometer However, in the camera, as the input device, the characterization is an inaccurate and needs the manual works in the process obtaining the output signal because the input signal can not be generated. Moreover, after gamut mapping process, the noise is increased because the optimized gamma tone curve of camera for the noise is distorted by the characterization. Thus, this paper proposed the system of obtaining the output signal of camera and the method of gamma correction for the noise. The camera's output signal is obtained by RGB values of patches from captured the color chart image. However, besides the illumination, the error for the location of the chart in the viewfinder is generated when many camera modules are captured the chart. The method of correcting the position to correct the error from manual works. The position of camera is estimated by captured image. This process and moving of camera is accomplished repeatedly, and the optimized position can be obtained. Moreover, the lightness curve of camera output is corrected partly to reduce the noise from the characterization process.

• Journal of Broadcast Engineering
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• v.16 no.3
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• pp.510-519
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• 2011

Intra mode decision is a useful coding tool in Distributed Video Coding (DVC) for improving DVC coding efficiency for video sequences having fast motion. A major limitation associated with the existing intra mode decision methods, however, is that its efficiency highly depends on user-specified thresholds or modeling parameters. This paper proposes an entropy-based method to address this problem. The probabilities of intra and Wyner?Ziv (WZ) modes are determined firstly by examining correlation of pixels in spatial and temporal directions. Based on these probabilities, entropy of the intra and the WZ modes are computed. A comparison based on the entropy values decides a coding mode between intra coding and WZ coding without relying on any user-specified thresholds or modeling parameters. Experimental results show its superior rate-distortion performance of improvements of PSNR up to 2 dB against a conventional Wyner?Ziv coding without intra mode decision. Furthermore, since the proposed method does not require any thresholds or modeling parameters from users, it is very attractive for real life applications.

• Journal of Broadcast Engineering
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• v.18 no.2
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• pp.178-184
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• 2013

In this paper, we propose an efficient parallelization technique of PU-level motion estimation (ME) in the next generation video coding standard, high efficiency video coding (HEVC) to reduce the time complexity of video encoding. It is difficult to encode video in real-time because ME has significant complexity (i.e., 80 percent at the encoder). In order to solve this problem, various techniques have been studied, and among them is the parallelization, which is carefully concerned in algorithm-level ME design. In this regard, merge estimation method using merge estimation region (MER) that enables ME to be designed in parallel has been proposed; but, parallel ME based on MER has still unconsidered problems to be implemented ideally in HEVC test model (HM). Therefore, we propose two strategies to implement stable parallel ME using MER in HM. Through experimental results, the excellence of our proposed methods is shown; the encoding time using the proposed method is reduced by 25.64 percent on average of that of HM which uses sequential ME.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.4
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• pp.42-50
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• 2008

The real-time bio-signal monitoring system based on the ZigBee and SIP/RTP has proposed and implemented for telemedicine but that has some problems at the stabilities to transmit bio-signal from the sensors to the other sides. In this paper, we designed and implemented a real-time bio-signal monitoring system that is focused on the reliability and efficiency for transmitting bio-signal at real-time. We designed the system to have enhanced architecture and performance in the ubiquitous sensor network, SIP/RTP real-time transmission and management of the database. The Bluetooth network is combined with ZigBee network to distribute traffic of the ECG and the other bio-signal. The modified and multiplied RTP session is used to ensure real-time transmission of ECG, other bio-signals and speech information on the internet. The modified ECG compression method based on DWLT and MSVQ is used to reduce data rate for storing ECG to the database. Finally we implemented a system that has improved performance for transmitting bio-signal from the sensors to the monitoring console and database. This implemented system makes possible to make various applications to serve U-health care services.

• Journal of Broadcast Engineering
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• v.24 no.6
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• pp.948-955
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• 2019

As interests in 360-degree VR (Virtual Reality) video services enormously grow, compression and streaming technologies for VR video data have been rapidly developed. Quality Emphasized Region (QER) based streaming scheme has been developed as a kind of viewport-adaptive 360-degree video streaming technology for maintaining immersive experience and reducing bandwidth waste. For selecting a QER corresponding to the user's gaze coordinate, QER-based streaming scheme requires the calculation of Quality Emphasis Center (QEC) distance and signaling message delivery for requesting QER switching. QEC distance calculations require high computational complexity because of repeated calculations as many times as the number of QERs. Furthermore, the signaling message interval results in a trade-off relationship between efficient bandwidth usage and flexible QER switching. In this paper, we propose an improved QER selection algorithm based on MMT protocol to solve this problem. The proposed algorithm could achieve computational complexity reduction by using preprocessed QER_ID_MAP. Also, flexible QER switching could be achieved, as well as efficient bandwidth utilization by an adaptive adjustment of the signaling interval.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.3
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• pp.161-172
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• 2013

Metadata registry (MDR) is the international standard, developed by ISO/IEC for exchange and sharing data between databases. Many MDR systems are used in diverse domains such as medical service, bibliography, environment for sharing and integrating data. However, those systems have different physical structures individually because the MDR standard defines only the metamodel for registering and storing metadata. It causes heterogeneity between the system structures and requires additional cost to maintain interoperability. ISO/IEC 13249-8 Metadata Registry Access (MRA) is developing as an international standard to provide a consistent access facility to data stored in different metadata registries. However, MRA does not consider the relationships between the concepts (classes) defined in the MDR specification. It causes that incorrect query results returned from MDR systems. It also requires additional cost of modeling and rewriting queries to reflect each physical model. Therefore, this paper suggests eMRA which considers the relationships between the concepts in MDR. The comparative evaluations are described to show the advantages of eMRA. eMRA has superior performance in query modeling and referential integrity than MRA defined by the relationship between the concept of MDR.