• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.5
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• pp.951-959
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• 2001

Video database has the function that stores videos and retrieves the video informations for the service request of users. Therefore, the purpose of the video database is to provide not only an environment both convenient and efficient for retrieving and storing video, but also to serve the requested video informations with rapid startup latency for more users. But, some users of video database as VOD application might tolerate slow startup latency because they would watch video during one hour or two hours. In this paper, we propose the novel policy of the storage system of video database, which serves efficiently the users by considering the classes of the users in video database. The policy admits the random movements of disk heads for urgent user classes but maintains the sequential or restricted movements of disk heads for less-urgent user classes like VOD application in storage system of video database. So, it can not provide only rapid startup latencies for urgent requests but also it can process more service requests in all.

• Journal of the Korea Society of Computer and Information
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• v.17 no.4
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• pp.51-58
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• 2012

Recently, 3D technology based on depth image is widely used in various fields including 3D space recognition, image acquisition, interaction, and games. Depth camera is used in order to produce depth image, various types of effort are made to improve quality of the depth image. In this paper, we suggests using area-based Canny edge detector to improve depth image in applying 3D technology based on depth camera. The suggested method provides improved depth image with pre-processing and post-processing by fixing image quality deterioration, which may take place in acquiring depth image in a limited environment. For objective image quality evaluation, we have confirmed that the image is improved by 0.42dB at maximum, by applying and comparing improved depth image to virtual view reference software. In addition, with DSCQS(Double Stimulus Continuous Quality Scale) evaluation method, we are reassured of the effectiveness of improved depth image through objective evaluation of subjective quality.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.157-163
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• 2013

The development of the latest media technology has changed the traditional broadcasting system. The traditional broadcasting system, which was operated by the mass media and the terrestrial broadcasters, is now transformed to the viewer-centered and bidirectional media through the convergence of internet and mobile. In terms of broadcasting environment, the function of the traditional TVs has been changed to the Smart TVs combined with an open platform which not only deliver visual contents, but also supply various applications and additional information linking the content providers and viewers. This ongoing broadcasting environmental change has made it possible for viewers to participate in the programs such as reality shows or sports events through SNS, texting or phone calls. Therefore, the purpose of this experiment is to present the ways to promote easier and more convenient viewer-participation in the programs by applying mobile messenger to existing broadcasting system in order to enhance the involvement of broadcasters and viewers of the programs and to diversify the roles of content providers and viewers in broadcasting.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.74-82
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• 2008

In this paper, we propose a P2P based IPTV system using a multiple chain architecture. Proposed system is robust to the peer churn. As opposed to the internet the IPTV network managed by a single ISP has fewer bandwidth constraints and end-to-end connectivity. So, we emphasize preferentially robustness of a P2P network in IPTV environment. A single chain structure which was proposed previously emphasizes simplicity, however there exists considerable delay time at the end part of peers as the number of peers increasing. As a solution to the problem, we propose the scheme which seperates the chain into several levels and again divides each level into spans to diminish a delay time. Though the chain is separated into level and span, basic structure of proposed scheme is still a chain structure. So the scheme simplifies the recovery procedure caused by join or departure of peers. We will show the improved performance of proposed scheme rather than single chain structure with respect to the delay time and reliability.

• The KIPS Transactions:PartD
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• v.16D no.3
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• pp.441-450
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• 2009

This paper describes the design and implementation of Personal Mobile Broadcasting Service which bases on embedded Linux and it supports personal broadcasting in wireless network environments. Recently, with the advent of various wireless networks and the increased use of high performance mobile devices, the demand for personal mobile broadcasting is being increased. The personal mobile broadcasting service makes it possible that mobile users create contents using their own mobile devices while they are moving or they are in any place. And then, it sends the created contents to server in real-time where their blogs are. Users connected to the content creator's blog can play the contents in real-time. With the implemented personal mobile broadcasting service, mobile users can share multimedia contents in real-time through wireless networks. And, it also helps users to construct their own broadcasting stations where they can broadcast the scene of the accident or public performance in real-time.

• Journal of Digital Convergence
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• v.17 no.9
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• pp.13-22
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• 2019

In the midst of the rapid changes in the digital media environment, this study try to examine the challenges of the public service broadcasting(PSB) news as a representative public sphere in a democratic society, and sought realistic alternatives through a case study of the BBC, one of the most successful digital policies of PSB in the world. The study found that the BBC's 'Digital First' strategy pursued a fundamental change in news formats, thereby simultaneously innovating on content. It was also interesting to see that the news consumers' needs for social media and video content were selectively analyzed and approached with a strategy of choice and focus. Finally, the production of customized digital content by analyzing news viewing behavior by each age group also suggests a lot to Korean PSB. I hope that the cases of this study will be reflected in the digital policies of Korean PSB.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.3
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• pp.67-78
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• 2010

CAS(Conditional Access System) is used in Pay-TV System to prohibit unauthorized user(s) accessing the contents in IPTV broadcasting environment. In the CAS, Smartcard transfers CW which is necessary in the process of descrambling the scrambled program to STB. CW hacking problem is one of the most serious problems in pay-TV system. There have been many researches on generating secure communication channel between smartcard and STB for secure transmitting, But they had problems in efficiency and security. In this paper, we propose a lightweight key agreement protocol based on a symmetric key algorithm. We show that our proposed protocol is more efficient than existing protocols by comparing the amount of computations, and analyzing the security requirement of the proposed protocol.

• Journal of Practical Engineering Education
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• v.14 no.2
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• pp.295-303
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• 2022

This study compares two cases in which flipped learning is applied in the active learning classroom (ALC) and fixed classroom of advanced engineering education. To this end, the difference in pre-learning, academic achievement, and class satisfaction between ALC and fixed classroom flipped learning were compared. The results revealed that students in ALC flipped learning watched more video lectures for pre-learning than those in the fixed classroom flipped learning and achieved higher scores on final tests, though they obtained lower points on midterm exam. In addition, examination of class satisfaction with questions about class factors, instructor factors, and overall satisfaction revealed that ALC flipped learning showed higher satisfaction in all factors than the fixed classroom flipped learning. This case study suggests that the ALC environment, a learning space built to facilitate learner-centered activities, is more effective for flipped learning that requires active interaction in the classroom.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.735-745
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• 2023

The purpose of this study is to examine how the control of an agent according to a driver's social status affects user experience factors in a multi-user environment of self-driving vehicles. We conducted a user study where participants viewed four scenarios (route changing/parking x accepting/declining a fellow passenger's command) and answered a survey, followed by a post-hoc interview. Results showed that either the routing scenario or accepting a passenger's command scenario had higher usefulness (convenience, effectiveness, efficiency) than their counterparts. Regardless of the car owner's social status, participants rated AI agents more positively when they met their goals effectively. They also stressed that vehicle owners should always be in control of their agents. This study can provide guidelines for designing future autonomous driving scenarios where an agent interacts with a driver, and passengers.

• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.113-128
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• 2022

The objective of this study is to pay attention to the personal media environment that is in the center of rapid changes in the media industry, to especially explore the activity area of one-person or minority media creators who lead the mobile media environment that could be connected, watched, and produced anywhere, and to closely examine the mutual ecosystem between creators and viewers. Especially, paying attention to the recommendation service YouTube provides, for example, based on the big data algorithm related to users' habitual use, when users' data used are provided more, the users face the advanced service, this study aimed to examine the effects of recommendation service on the formation of trust between user and producer, user flow, and subscription intention, and also to demonstrate the process of forming this mutual relation through concrete data. In the conclusion, implications that can be inferred based on the research results and suggestions for further research in the future were presented.