• The Journal of the Korea Contents Association
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• v.10 no.1
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• pp.160-169
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• 2010

The mobile internet service market is growing very rapidly in Korea. This study outlines the current state of mobile internet services and analyzes the mobile contents types of media companies, especially newspapers, broadcasters and internet portal firms. As a result of this study, media companies provide generally different types of news and information for free and they are eager to develop the new mobile business models to maintain their power in new media. But mobile content distribution is still in the early stages due to the lack of clear business models. To satisfy the consumer's needs and to maintain the competitive advantages, the media companies should develop new business models and cooperate with other market participants to reduce the barriers in the mobile internet service market.

• Transactions of the Society of Information Storage Systems
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• v.11 no.2
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• pp.31-35
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• 2015

The Blu-ray Disc Recordable-Triple Layer (BD-R TL) media is considered as one of strong candidates for archival application among optical media formats, due to its large capacity. However, the long-term stability and degradation aspect have not been fully understood yet for BD-R TL media. Thus, the BD-R TL media were recorded at full tracks and analyzed by the random-symbol error rate (R-SER) measurement at different recording layers and recording positions after the accelerated aging test to understand its long-term stability. Finally, the general degradation aspect of BD-R TL media was discussed to improve the long-term stability.

• ETRI Journal
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• v.43 no.3
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• pp.400-413
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• 2021

This paper theoretically and empirically explores the reliability gain that can be obtained by installing multiple antennas in on-vehicle broadcasting receivers. Analytical derivations reveal that maximal-ratio-combining-based diversity allows a multi-antenna receiver (MR) to achieve significantly better coverage probability than a single-antenna receiver (SR). In particular, the notable MR gains for low-power reception and high-throughput services are highlighted. We also discuss various aspects of mobile MRs, including geometric coverage, volume of the users served, and impact of receiver velocity. To examine the feasibility of MRs in the real world, extensive field experiments were conducted, particularly with on-air ATSC 3.0 broadcast transmissions. Relying on the celebrated erroneous second ratio criterion, MRs with two and four antennas were verified to achieve notable reliability gains over SRs in practice. Furthermore, our results also prove that layered-division multiplexing can cope better with receiver mobility than traditional time-division multiplexing when multiple services are intended in the same radio frequency channel.

• ETRI Journal
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• v.42 no.6
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• pp.827-836
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• 2020

Measuring the diffraction loss for high frequencies, long distances, and large diffraction angles is difficult because of the high path loss. Securing a well-controlled environment to avoid reflected waves also makes long-range diffraction measurements challenging. Thus, the prediction of diffraction loss at millimeter-wave frequency bands relies on theoretical models, such as the knife-edge diffraction (KED) and geometrical theory of diffraction (GTD) models; however, these models produce different diffraction losses even under the same environment. Our observations revealed that the KED model underestimated the diffraction loss in a large Fresnel-Kirchhoff diffraction parameter environment. We collected power-delay profiles when millimeter waves propagated over a building rooftop at millimeter-wave frequency bands and calculated the diffraction losses from the measurements while eliminating the multipath effects. Comparisons between the measurements and the KED and GTD diffraction-loss models are shown. Based on the measurements, an approximation model is also proposed that provides a simple method for calculating the diffraction loss using geometrical parameters.

• The Journal of Korean Academic Society of Nursing Education
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• v.27 no.4
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• pp.359-368
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• 2021

Purpose: The purpose of this study was to investigate the mediating effect of self-leadership on the relationship between media literacy and learning agility in nursing students based on their experiences in online classes during the Coronavirus Disease-19 pandemic. Methods: A descriptive survey was conducted among 165 nursing students from four universities in Busan. Data were collected from June 2 to 13, 2021, and was analyzed using a t-test, one-way ANOVA, Pearson's correlation coefficients, and stepwise multiple regression with SPSS/WIN 26.0. Results: Significant relationships were found between learning agility and media literacy (r=.62, p<.001), between learning agility and self-leadership (r=.58, p<.001), and between media literacy and self-leadership (r=.53, p<.001). Additionally, self-leadership had a partial mediating effect on the relationship between media literacy and learning agility (Z=4.30, p<.001); its explanatory power was 46.0%. Conclusion: These results indicate that interventions to increase the level of media literacy, along with self-leadership, are necessary to improve the level of learning agility of nursing students who will be essential human resources in a rapidly changing healthcare field.

• Journal of Sensor Science and Technology
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• v.24 no.5
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• pp.342-347
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• 2015

We introduce an indoor broadcasting system using light-emitting diode (LED) lamps coupled with a 220 V power line. Two couplers connected to the power line constitute a power line communication (PLC) link. The transmission path from an LED lamp to a photodetector forms a visible light communication (VLC) link in free space. When the LED lamp is coupled to the power line, a composite PLC-VLC link is formed, making it possible to transmit a VLC signal beyond line-of-sight. In experiments, a 4 kHz analog signal modulated with a 100 kHz carrier was sent to the power line by a PLC coupler, and LED lamps coupled to the power line detected the signal and radiated it to multiple VLC receivers in the room. This configuration is useful in expanding an indoor VLC sensor network to adjacent rooms or constructing a voice broadcasting system in a building or apartments with existing power lines.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.181-185
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• 2008

Recently, the Virtual Reality(VR) became one of the most powerful tools in making media files. In the field of engineering, while it is increasing to use 3D CAD model in the process of design to manufacturing, the VR is not popular in comparison with media business. XVL(eXtensible Virtual Reality Markup Language) is one of XML(eXtensible Markup Language) which is a standard web media language. XVL provides the connection between 3D CAD data and virtual reality, and it can be easily published through internet for the engineering purpose. In this study, a web based VR model for major components in a nuclear power plant has been developed by using XVL and corresponding 3D CAD data. The proposed model is expected to be used in the engineering field to cooperate among experts, and also, it will provide more plausible explanation to ordinary people.

• Journal of Korea Multimedia Society
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• v.19 no.4
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• pp.756-764
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• 2016

In this paper, we present electroencephalography (EEG)-based power spectra analysis and auditory stimuli methods as coping mechanisms for disgust affection and phobia. Disgust affection is a negative emotion generated from trying to eliminate something harmful to one. It is usually related to mental illnesses such as obsessive-compulsive disorder, specifically phobia and depression. In our experiments, participants watched videos on horrible body mutilation and disgusting creatures, with either the original sound track or relaxing and exciting music as auditory stimulation. After watching the videos with original sound track, the participants watched the same video with a different audio background, such as soothing or cheerful music. We analyzed the EEG data utilizing relative power spectra and examined survey results of the participants. The results demonstrated that disgust affection is decreased when participants watched the video with relaxing or exciting music instead of the original soundtracks. Moreover, we confirmed that human's brainwave reacts according to types of audio and sources of disgust affection.

• Nuclear Engineering and Technology
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• v.49 no.1
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• pp.92-102
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• 2017

The analysis of steam generators as an interface between primary and secondary circuits in light water nuclear power plants is crucial in terms of safety and design issues. VVER-1000 nuclear power plants use horizontal steam generators which demand a detailed thermal hydraulics investigation in order to predict their behavior during normal and transient operational conditions. Two phase flow field simulation on adjacent tube bundles is important in obtaining logical numerical results. However, the complexity of the tube bundles, due to geometry and arrangement, makes it complicated. Employment of porous media is suggested to simplify numerical modeling. This study presents the use of porous media to simulate the tube bundles within a general-purpose computational fluid dynamics code. Solved governing equations are generalized phase continuity, momentum, and energy equations. Boundary conditions, as one of the main challenges in this numerical analysis, are optimized. The model has been verified and tuned by simple two-dimensional geometry. It is shown that the obtained vapor volume fraction near the cold and hot collectors predict the experimental results more accurately than in previous studies.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.85-88
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• 2000

Distributed Control System(DCS) is one of the best solutions to implement control systems because it provides continuous observation of control process and execution of commands to induce proper operations. In this paper, a design of control network for DCS in nuclear power plant is proposed. The proposed control network on DCS has a simple architecture and deterministic property. Thus, the proposed control network offers hard real-time periodic service. It also has redundant media for the fault-tolerance. As a result, high safety and reliability required in nuclear power plant are guaranteed.