• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.127-132
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• 2014

In this paper, we propose a digital signage method that can control the contents of the screen and download the desired files to individual smart terminal with no touch of digital signage screen by using Kinect. The main features and contributions of the proposed method are as follows. First, can solve the problems such as the risk of bacterial infection, not cleanliness on the screen as well as maximize advertising effectiveness. Second, can support bi-directional communications with computer while we touch only wanted advertisements. The performance evaluation shows the effectiveness of the proposed method. Especially, we can see that the proposed system operates through the recognition of user's actions when the cursor is within the scope of a certain coordinate and the file transfer time to download information is different depending on the PC performance and the version of personal smart device.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.787-790
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• 2003

A 4-wavelength optical transceiver system is designed and implemented by using 4 OADMs (optical add-drop multiplexers), WDMs, and optical transceivers. In this new system, the wavelengths of 1510 nm and 1530 nm are used for upload and download signals, respectively, as well as the wavelengths of 1550 nm and 1310 nm which have been utilized in a 2-wavelength optical transceiver systems. The 4-wavelength optical module shows very encouraging pass characteristics of about - 5 dB and isolation characteristics of less than -40 dB, which is configured with two OADMs, 4 couplers, and WDM couplers by fusion splicing. Noise figure (NF) of the one-stage balanced amplifier designed and fabricated for receiver module is 0.38 dB and the amplifying gain is 14.2 dB. S$_{11}$, S$_{22}$ and input, output VSWR are -28.81 dB, -32.08 dB, 1.05 : 1, 1.08 : 1, respectively.y.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.800-806
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• 2015

WAVE(Wireless Access in Vehicular Environments) system is wireless communication technology that vehicle sends and receives packets between vehicles or between vehicles and infrastructure in a high-speed mobile environment. In this study, we have designed and implemented a CRL(Certificate Revocation List) download protocol that is used to verify certificate revocation status of the other party when the vehicles communicate with WAVE system. This protocol operates over UDP. And to support security features, also, ECDSA(Elliptic Curve Digital Signature Algorithm) is used for mutual authentication and ECIES(Elliptic Curve Integrated Encryption Scheme) is used to ensure the confidentiality. Moreover, this protocol ensures the integrity of data by adding MAC(Message Authentication Code) to the end of packet and support the error and flow control mechanisms.

• The Journal of the Korea Contents Association
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• v.14 no.12
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• pp.924-934
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• 2014

In the last 10 years the digital music contents market has grown rapidly. However digital music contents product and services are not managed with product planning and price policy considered customer attitude and digital music contents values. This study is to define the value properties of digital music contents services based on streaming and download as genre, price, sound quality, and usage appliance, and suggest the strategic market price and service composition of digital music contents service by customer attitudes about the value properties. The research used the conjoint analysis methodology based on the hedonic price model and collected 405 questionaries by users of Korean digital music contents services to the analysis. Hence 'sound quality' in download platform, and 'appliance' in streaming platform were the elements to evaluate the customer attitude. The results present the music contents productions and companies have to provide the differentiated services and price by the value properties of user preference in the market.

• The Journal of the Korea Contents Association
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• v.9 no.11
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• pp.212-224
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• 2009

Proliferation of high performance internet infrastructures finally allows their users download a single copy of regular movie just within in a couple of seconds. Ease of accesses to the software for downloading consequently leads them insensitive to the ethics or legitimacy of their conduct. Thus, strong legal action is enforced for piracy over nationally through strengthen the copyright law. We in this paper conducted a survey to see whether netizens prefer to download just for the matter of their convenience. Whilst the level of awareness is addressed even in a far-fetched manner in the area of music piracy and computer software piracy, the case of movie is much different in that we even fail to find any survey that has been made for movie piracy. The survey has been made by devising questionnaires for netizens and it was posted web WorldSurvey, which is the most prominent online survey site in Korea. To our surprise, 9 out of 10 respondents expressed they actually resort to illegal downloading for the reason of convenience. We realized one more surprise. More than 95% of netizens conspicuously aware of their downloading behaviors are mischievous and illegal without reservation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.5
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• pp.83-90
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• 2012

This paper is a research on the design and implementation of a small real-time radio broadcasting system by using smart phone based on Android. It was designed as the server-client structure, and used the progressive download of HTTP as methods of transferring data to further simplify the system. In order to realize the real-time broadcasting, the original audio source was divided with a short interval and captured to be compressed and stored into files. Then the client receives and plays the compressed files sequentially as it is downloaded. However, this method occurs two problems each of which is the loss of capturing the original source in the server and the discontinuity of playing the files in the client. We solved the problem in the server by separating the thread into two parallel threads of which is each captured and compressed/stored, also by using the double buffering method. The problem in the client was solved using MediaPlayer in Android and the file queue to store the multiple files.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.1
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• pp.108-115
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• 2011

Virtual Robot Education System (VRES), which is for programming education with a Lego Mindstorm NXT robot, is designed and implemented. Through this system, program learners can edit source code, compile, download it into the robot, and run their executive program. In order to observe it, the system includes web cameras and provide monitoring services. Thus, students are able to verify the operation of robot into which they download their program in detail and to debug if necessary. In addition, we design a new simple user-friendly programming language and a corresponding compiler for it. With those tools, learner can more easily create programs for NXT robot and test them than Java language. A educator can control and manage the robot for the subject of a class with direct control mode of our system. Therefore, the proposed system is able to support students to learn robot programming during or after regular classes with web browsers through Internet.

• Convergence Security Journal
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• v.14 no.4
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• pp.61-71
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• 2014

In recent years, malwares in Android smartphones are becoming increased explosively. Since a great deal of appsare deployed day after day, detecting the malwares requires commercial anti-virus companies to spend much time and resources. Such a situation causes malwares to be detected after they have become already spread. We propose a scheme called TAU that dynamically tracks application behaviors to specify apps with potential security risks. TAU keeps track of how a user's interactions to smartphones incurs the app installation, the route of app spread, and the behavior of app execution. This tracking specifies apps that have the possibility of attacking the smartphones using the drive-by download and update attack schemes. Moreover, the tracked behaviors are used to decide whether apps are repackaged or not. Therefore, TAU allows anti-virus companies to detect malwares efficiently and rapidly by guiding to preferentially analyze apps with potential security risks.

• Journal of Communications and Networks
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• v.14 no.3
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• pp.286-295
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• 2012

To meet the increased demand of video-on-demand (VoD) services, peer-to-peer (P2P) mesh-based multiple video approaches have been recently proposed, where each peer is able to find a video segment interested without resort to the video server. However, they have not considered the constraint of the server's upload bandwidth and the fairness between upload and download amounts at each peer. In this paper, we propose a novel P2P VoD streaming system, named peer cache adaptation (PECAN) where each peer adjusts its cache capacity adaptively to meet the server's upload bandwidth constraint and achieve the fairness. For doing so, we first propose a new cache replacement algorithm that designs the number of caches for a segment to be proportional to its popularity. Second, we mathematically prove that if the cache capacity of a peer is proportional to its segment request rate, the fairness between upload and download amounts at each peer can be achieved. Third, we propose a method that determines each peer's cache capacity adaptively according to the constraint of the server's upload bandwidth. Against the proposed design objective, some selfish peers may not follow our protocol to increase their payoff. To detect such peers, we design a simple distributed reputation and monitoring system. Through simulations, we show that PECAN meets the server upload bandwidth constraint, and achieves the fairness well at each peer. We finally verify that the control overhead in PECAN caused by the search, reputation, and monitoring systems is very small, which is an important factor for real deployment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.12
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• pp.1184-1191
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• 2009

In order to reduce the download around the Smart UAV(SUAV) at Transition mode, flow control using synthetic jet has been performed. Many of the complex tilt rotor flow features are captured including the leading and trailing edge separation, and the large region of separated flow beneath the wing. Based on the results of part 1 of the present work, synthetic jet is located at 0.01c, $0.95c_{flap}$ and it is operated with the non-dimensional frequency of 0.5, 5 to control the leading edge and trailing edge separation. Consequently, download is substantially reduced compared to with no control case at transition mode using leading edge jet only. The present results show that the overall flight performance and stability of the SUAV can be remarkably improved by applying the active flow control strategy based on synthetic jet.