• The Transactions of the Korea Information Processing Society
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• v.7 no.4
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• pp.1184-1192
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• 2000

Multicast has communication mechanism that is able to transfer voice, video for only the specific user group. As compared to unicast, multicast is more susceptive to attack such as masquerading, malicious replay, denial of service, repudiation and traffic observation, because of the multicast has much more communication links than unicast communication. Multicast-specific security threats can affect not only a group's receivers, but a potentially large proportion of the internet. In this paper, we proposed the multicast security model that is able to secure multi-group communication in CBT(Core Based Tree), which is multicast routing. And designed the multicast key distribution protocol that can offer authentication, user privacy using core (be does as Authentication Server) in the proposed model.

• ETRI Journal
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• v.33 no.3
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• pp.355-365
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• 2011

IPTV broadcast channels and video content distribution are increasingly saturating network paths. New solutions based on inter-domain multicast protocols could contribute to the enhancement of multimedia content distribution over the Internet. The aim of this paper is to propose new capabilities for an existing inter-domain multicast protocol, the Protocol Independent Multicast-Sparse Mode. We describe the modified protocol and analyze its behavior using newly developed tools based on an open-source software simulator. The resulting protocol does not require topology information, which is advantageous for easier deployment. In addition, the adopted solution avoids inherent problems with inter-domain multicast routing, such as multiple paths and path asymmetries.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.3
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• pp.18-27
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• 1996

By integrating WDM to OPS unit which plays an improtant role for the reliability of CPN, we made it possible to provide CATV, VOD, and high-speed data services simultaneously and to meet easily the requirements for new services in the future. For the design of optimal system, the link analysis of power budget has been perfomred. Also, the prototyped system has been tested with STM-1 level signals to confirm functions such as transmission, distribution, and protection. The results proved that when occurred out-of-order or recovery of ONU, the system did the pertinent switching with minimum loss for high-speed data services. Also for video distribution services, the system has distributed STM-1 level signals sucessfully.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06a
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• pp.23.1-28
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• 1999

InterSpaceTM is an advanced networked virtual reality system that presents shared three-dimensional computer graphics (CG) worlds via the Internet where multiple users can enjoy synchronous communications with voice, video and text. Users can control their avatars as a surrogate interface. In InterSpace users can walk around and interact with other people and interact with contents. In this paper, we describe the function-distributed architecture used in InterSpace. The architecture enables flexible configuration of server functions and load distribution. It also allows users to select media and client PCs to switch servers dynamically.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5669-5684
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• 2018

The new mobile edge network architecture has been required for an increasing amount of traffic, quality requirements, advanced driver assistance system for autonomous driving and new cloud computing demands on highway. This article proposes a hierarchical cloud computing architecture to enhance performance by using adaptive data load distribution for buses that play the role of edge computing server. A vehicular dynamic cloud is based on wireless architecture including Wireless Local Area Network and Long Term Evolution Advanced communication is used for data transmission between moving buses and cars. The main advantages of the proposed architecture include both a reduction of data loading for top layer cloud server and effective data distribution on traffic jam highway where moving vehicles require video on demand (VOD) services from server. Through the description of real environment based on NS-2 network simulation, we conducted experiments to validate the proposed new architecture. Moreover, we show the feasibility and effectiveness for the connected car media service on highway.

• Journal of Distribution Science
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• v.18 no.3
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• pp.87-97
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• 2020

Purpose: The aim of this study is to understand the internal and external responses that consumers experience when they are exposed to an innovative system in retail stores. This study considered the SST(Self-Service Technology) system in a retail setting as a type of functional environmental stimuli and selected a smart shopping cart as an example of SST system. The influences of functional environmental stimuli on consumers' emotional, cognitive, and behavioral responses were examined by applying S-O-R model. In addition, this study attempted to extend the traditional S-O-R model by (a) incorporating personal characteristics variables such as time pressure and perceived crowding and (b) considering not only emotional but also cognitive aspects of consumers' internal responses. Research Design, Data, and Methodology: This study used a video-scenario technique. Participants watched a video about grocery shopping situations using a smart shopping cart and responded to their emotional, cognitive, and behavioral responses. An online survey was conducted using Amazon's Mechanical Turk (N = 185). All participants were US consumers over 20 years old and had been shopping at the grocery store in the last month. Data were analyzed through structural equations modeling with AMOS 20. Results: Test results showed that consumers who perceived higher levels of time pressure and perceived crowding in usual shopping situations were more likely to evaluate the SST system favorably. The results showed that personal characteristics have a significant impact on consumers' evaluation of functional environmental stimuli in retail setting. As consumers evaluated the SST system favorably, they experienced more positive affect and less negative affect during their shopping behaviors. Positive affect led to good service quality inference, which further increased patronize intention. However, negative affect did not show a significant impact on service quality inference, but only on patronize intention. Conclusions: This study attempted to investigate the influence of SST system by extending the traditional S-O-R model. This study classified the SST system as functional environmental stimulus of retail stores and analyzed the effect of stimulus on consumers' internal and external responses. The results of this study showed that the introduction of innovative SST can serve as an effective store differentiation strategy in an increasingly competitive retail environment.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.1
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• pp.133-143
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• 1996

The constant modulus algorithm (CMA), one of the widely used blind equalization algorithms, equalizes channels using the second-order statistic of equalizer outputs. The performance of the CMA for multi-level signals such as the quadrature amplitude modulation (QAM) signal degrades because the CMA maps all signal power onto a single modulus. in this paper, to improve the equalization performance of a QAM system, we propose a shell partitioning method based on error magnitude. We assume the probability distribution of an equalizer output as Gaussian, and obtain decision boundaries by maximum likelihood estimation based on the fact that the distribution of the equalizer output power is noncentral $x^2$. The proposed CMA constructs a multi-moduli equlization system based on the fact that each shell separated by decision boundaries employs a single modulus. Computer simulation results for 32-QAM and 64-QAM show the effectiveness of the proposed algorithm.

• The Journal of the Korea Contents Association
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• v.16 no.1
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• pp.241-255
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• 2016

This study aims at examining the making and distribution course of performing arts and its converged form with technology and industry in terms of the Contents Promotion Act. Since the 2000s, the inter-area contents making and sharing methods have been changing the making and distribution structure of performing arts. The recent production of performing arts contents live videos extends the areas of arts creation and communication beyond the time and spatial boundaries of performing arts and changes the existing systems. The performing arts which started with nowness and spatio-temporal restriction on the premise is now creating a new platform over the spatio-temporal boundary through the live video. Performing arts, in convergence with the areas of technology and industries, expands universal approaches and shows the public value of cultural fairness at public performing arts centers. In this context, this study aims at seeking the possible extension of performing arts contents by examining how the so-called high-class performing arts such as opera, theatre and classical music combines with the visual industry.

• Journal of Distribution Science
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• v.14 no.10
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• pp.127-136
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• 2016

Purpose - This study investigated the effects of lectures in the English medium (EML) on understanding and learning outcomes. Sixty percent of EML lectures in Korea also use Korean for further support. Thus, this situation needs to clearly distinguish the specific impacts of the EML classes on learning outcomes. Here, we use the same English materials, including PowerPoint slides and video content, given in the Korean and English lectures. The difference between the lectures becomes only whether the lecture is delivered in Korean or English. Thus, we can clearly identify whether the language difference makes any difference in learning outcomes. Research design, data, and methodology - Our sample consisted of 91 students taking an international business course the spring of 2015. All course materials, including textbooks, PowerPoint slides, exams, video, and support content, were presented in English. Survey data and exam results were used. Students filled out their student identification number and name, so we could match the surveys against the exam results. Results - First, results show that whether the lecture was delivered in English or Korean was an important factor when students chose the class. Second, English proficiency related to international business and general English levels were higher in the English class than in the Korean class. However, the understanding of key concepts and reading abilities of international business newspapers were the same for students in both classes. Third, teaching materials and lectures were the most important material for the understanding of key concepts in the business major. Fourth, the exam results showed no difference in performance of the students in the English versus the Korean class. This shows that EML classes were not necessarily detrimental to the understanding of major concepts of the lecture. Thus, it is important that researchers carefully design empirical settings to study the effectiveness of EML. Conclusions - The English lecture can be as helpful for enhancing knowledge in the business major as the Korean lecture. For further research, various English lecture forms can be considered to distinguish the effects of the English lecture.

• The Journal of the Korea Contents Association
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• v.22 no.6
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• pp.135-144
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• 2022

This study explores that how the logic of network power in the existing digital content distribution structure works against local media. The limitless citation of local media content, in particular, is becoming more common in order to profit from network traffic while not giving appropriate remuneration for local media content. This study tried to demonstrate how network media dominance alienates local media material by using YouTube network analysis of TV Maile Shinmun. According to the research result, it was found that major news media tends to take profits from the local media interview by not properly indicating the source video, or reporting the core content of the local media interview, making it unnecessary to look for the original video source. Despite the viewpoint that the digital environment presents opportunities for local media, the current network logic would not benefit local media, which calls for the need that the digital content distribution strategy of local media develops a new order such as NFT, one of blockchain-based monetary system.h the help of information technology.