• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.3
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• pp.317-324
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• 2016

WiMedia provides the data rate of up to 1Gbps, but the transmission range is restricted to approximately 10 meters. When constructing a multi-hop WiMedia network to extend its coverage, conventional hop-based routing may not guarantee satisfactorily the required QoS. We propose two QoS routing techniques for the WiMedia-based wireless mesh network. The proopsed QoS routing reflects the characteristics of TDMA-based WiMedia MAC and develops QoS extensions separately for on-demand routing and table-driven routing. Through simulations, we identify that the QoS routing shows better performance than the hop-based routing. It also turns out that the QoS on-demand routing and the QoS table-driven routing show conflicting performance results depending on the transmission power.

• Journal of Broadcast Engineering
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• v.18 no.2
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• pp.215-224
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• 2013

With the rising popularity of smart-phones, the supply of Internet protocol television is largely increased and it causes the wireless communication network load to be increased. To overcome such an overloading problem, 3GPP is now working on the standardization of MBMS since LTE Release 6 specification. MBMS has good performance in bandwidth efficiency by sharing the same bandwidth with the mulitple MBMS users having the same content. According to the proposed algorithm, in heterogeneous networks having a dispersed Single-cell MBMS where 3GPP network and Wi-Fi network are mixed, if the number of MBMS users, who are belonging to cells supporting a dispersed Single-cell MBMS, is more than a specified threshold, the MBMS priority policy is operated. Otherwise, the Wi-Fi priority policy is executed. As the simulation results show both the increase of total available bandwidth ratio and the decrease of network usage cost, it is confirmed that the proposed scheme allows the network efficiency to be maximized.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.124-137
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• 2018

The OTT service in Korea is not as popular as that in the U. S. This study argues that one of the major reasons of poor performance of OTT in Korea is that the OTT service providers did not acquire attracting contents, thus failing to appeal to Korean users. The other reason is Korean users are not willing to use OTT services because of high telecommunications fees to use OTT services. That is why most OTT users are using OTT services in WiFi zones, such as house, workplace, or school. This study investigated the popular OTT contents in recent three years, and how these popular OTT contents are provided in OTT service platforms, and how these contents are used in different places. The results of this study may provide several implications for OTT service providers' strategies in the future, and propose policy implications for the development of OTT services in Korea.

• Smart Media Journal
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• v.12 no.6
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• pp.15-26
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• 2023

As face-to-face communication has become difficult due to the COVID-19 pandemic, studies have been conducted to understand the impact of non-face-to-face communication, but there is a lack of research that examines this through messenger application reviews. This study aims to identify the impact of the pandemic through Latent Dirichlet Allocation (LDA) topic modeling by collecting review data of 메신저 applications in the Google Play Store and suggest service strategies accordingly. The study categorized the data based on when the pandemic started and the ratings given by users. The analysis showed that messenger is mainly used by middle-aged and older people, and that family communication increased after the pandemic. Users expressed frustration with the application's updates and found it difficult to adapt to the changes. This calls for a development approach that adjusts the frequency of updates and actively listens to user feedback. Also, providing an intuitive and simple user interface (UI) is expected to improve user satisfaction.

• Smart Media Journal
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• v.12 no.6
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• pp.27-34
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• 2023

As Netflix usage has increased due to the COVID-19 pandemic, users' experiences with the service have also increased. Therefore, this study aims to conduct topic modeling analysis based on Netflix review data to explore the changes in Netflix user experience and service before and after the COVID-19 pandemic. We collected Netflix app review data from the Google Play Store using the Google Play Scraper library, and used topic modeling to examine keyword differences between app reviews before and after the pandemic. The analysis revealed four main topics: Netflix app features, Netflix content, Netflix service usage, and Netflix overall reviews. After the pandemic, when user experience increased, users tended to use more diverse and detailed keywords in their reviews. By using Netflix review data to analyze users' opinions, this study shows the changes in user experience of Netflix services before and after the pandemic, which can be used as a guide to strengthen competitiveness in the competitive OTT market.

• Journal of Broadcast Engineering
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• v.5 no.2
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• pp.159-166
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• 2000

This paper analyzed the transmission performance when we transmited digital TV signal through analog CATV network. We considered random noise, microreflection, and composite tripple beats as channel impairment factors, and random noise and CTB( Composite Tripple Beat) are modelled as Gaussian distribution and Weibull distribution respectively. Channel modellings for microreflections are classified as three cases, and we exploited carrier recovery and blind equalizer to minimize their effects. We developed a computer simulator for the digital transmission system using DVB-C specification to analyze digital transmission performance, and found BER values according to $E_{b}$/$N_{o}$ for each configuration.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.07a
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• pp.479-480
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• 2023

현대 사회는 출생아가 줄어들고 고령화 현상이 빠르게 진행 중이다. 20~30대의 사회 복지 종사자가 줄어들고 노인 인구는 늘어나는 반비례 현상이 나타나고 있다. 보호자가 없는 노인에게 낙상 사고와 같은 위급상황이 발생한다면 골든타임을 놓칠 수도 있을 것이다. 따라서, 본 논문에서는 낙상 사고 발생 시, 빠른 시간 내에 실시간 모니터링을 통해 노인 복지사가 상황을 인지할 수 있게 하는 시스템을 개발하였다. 미디어파이프 포즈 모델을 이용하여 관찰 대상의 움직임을 포착하도록 하였고 PTZ 카메라의 서보 모터 제어를 통해 포착한 관찰 대상을 추적하도록 하였다. 주요 장면은 사진으로 저장해 웹 서버로 전송하고, 심박수 측정 센서와 와이파이 통신 모듈이 장착된 아두이노 보드가 실시간으로 웹 서버로 전송하여, 전담 관리자는 사진을 통해 상황을 인식하고 심박수를 보고 얼마나 위급한지 알 수 있도록 하였다.

• Korean journal of communication and information
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• v.44
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• pp.44-75
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• 2008

The candle rally against the import of American beef which lasted for a long time was full of various types of social movement. That is, new media including mobile phone, Internet, Internet cafes played an important role in mobilizing people around the rally. Thus, this research focuses on the meaning and effect of these kinds of movement. In particular, it analyzed the possibility of real time broadcasting through the Internet as civic journalism, which received much attention in the rally. For this, this research used case study and interview as main research method. Case study focused on Internet cafes based on the media coverage of the rally. Interviews were conducted with workers at OhmyTV, Color TV, and 615TV. These workers at progressive media emphasized on the scene coverage as the advantage of real time delivery. Transmitting many citizens' voices was another advantage. It is expected that personal media and progressive media which try to show the scent as it is will play an important role in the future journalism with the expansion of Wibro.

• Journal of Digital Convergence
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• v.17 no.1
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• pp.337-345
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• 2019

In this study, it focused on observational documentary based on observation. This study comparatively analyzed how differently the narrative style is implemented depending on the social and cultural background of East and West by analyzing the narrative style of Frederick Wiseman, a representative director of observational documentary who has been active in foreign countries for a long time, and Lee Seung-jun, recently become active in Korea. As a result of the analysis, It might be too early to judge by simple comparison of two directors, but it became an opportunity to see the difference between the long-standing observer style and the observer style documentary which actively accepts the new form. While it cannot be simply judged which style is better between the traditional observer style which shapes the simple contents into conflicts in the sequence structure and the recent style which sublimates the human inner conflict into the drama, a side could have been seen that the diversity is attained. It can be judged that the traditional documentary film can be gradually changed later. It was found that the documentary can emerge from the logic that it is difficult and boring, and that the same theme can be various and creative depending on what style is chosen.

• The KIPS Transactions:PartA
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• v.17A no.3
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• pp.137-144
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• 2010

Recently, as the consumer market of the mobile device is explosively getting bigger and bigger, both of the usability and applicability of the mobile device are also growing rapidly. The customers prefer to transfer data between the different mobile devices and download multimedia data via the wireless connection even wherever they are. The trend of mobile devices also shows the tendency of employing the various connectivity technologies such as Bluetooth, Wi-Fi, W-USB, NFC, and so on in a single mobile device. With this market trend, the importance of the technology associating different devices is getting increased gradually. In this paper, we present how to support the NFC association of the W-USB technology by extending the existing NFC's handover protocol. We also explain the differences between the NFC association and the handover protocol, and propose the method to resolve the differences by extending the handover protocol of the NFC technology. Finally, we describe how to implement the NFC system supporting the W-USB handover protocol.