• 한국정보처리학회논문지
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• 제7권4호
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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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• 제33권3호
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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.

• 전자공학회논문지A
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• 제33A권3호
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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.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1999년도 KOBA 방송기술 워크샵 KOBA Broadcasting Technology Workshop
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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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• 제12권12호
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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.

• 유통과학연구
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• 제18권3호
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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.

• 전자공학회논문지B
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• 제33B권1호
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• pp.133-143
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• 1996

널리 사용되는 blind 등화 알고리듬의 하나인 constant modulus algorithm (CMA)은 등화기 출력신호의 2차 통계 특성을 이용하여 채널을 등화한다. Quadrature amplitude modulation (QAM) 신호와 같은 다중레벨을 갖는 신호에 대한 CMA의 성능은 모든 신호의 전력을 하나의 modulus에 투영시켜 등화함에 따라 성능이 떨어지게 된다. 본 논문에서는 QAM 시스템에 대한 등화성능을 개선시키기 위해 오차크기에 따른 shell 분할방법을 제안하였다. 등화기 출력신호의 분포를 가우시안으로 가정하여, 등화기 출력신호전력의 분포가 noncentral $x^2$ 분포를 이룸으로부터 maximum likelihood 추정에 의한 결정경계를 구했다. 결정경계에 의해 분리되는 각 shell이 하나의 modulus를 가짐에 착안하여 제안한 CMA는 다중 modulus 등화시스템을 구성한다. 32-QAM과 64-QAM 신호에 대한 전산모의실험을 통하여 제안한 알고리듬이 효과적임을 보였다.

• 한국콘텐츠학회논문지
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• 제16권1호
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• pp.241-255
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• 2016

본 연구는 공연예술의 제작 유통 과정을 콘텐츠진흥법상 기술 산업과의 융합형태를 살펴보고자 한다. 2000년대 이후 영역 간 콘텐츠 생산과 공유방식은 공연예술의 제작 유통구조를 전환시키고 있다. 최근 나타나고 있는 공연예술실황영상은 공연예술의 시공간적 경계를 뛰어넘어 예술 창작과 소통의 영역을 확장하여 기존 체계를 변화시키고 있다. 현재성과 공간적 제한성을 전제로 출발되었던 공연예술은 실황영상화를 통하여 시공간의 경계를 뛰어넘는 새로운 플랫폼을 창출하고 있다. 공연예술은 기술 산업 영역과 융합하여 보편적 접근성을 확대하는 계기를 마련하고 있으며, 문화적 형평성이라는 공공 공연장의 공공적 가치를 확장할 수 있는 가능성을 보여주고 있다. 이러한 맥락에서 본 연구는 고급예술로 불리어지는 오페라, 클래식, 발레 등의 공연예술이 영상산업과 어떤 방식으로 결합되고 있는지를 살펴봄으로서 공연예술콘텐츠의 가능성을 모색하고자 한다.

• 유통과학연구
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• 제14권10호
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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.

• 한국콘텐츠학회논문지
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• 제22권6호
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• pp.135-144
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• 2022

본 연구는 디지털 환경이 지역 언론의 기회라 보는 견해에도 불구하고, 기존의 디지털 콘텐츠 유통 구조에서 행사되는 네트워크 권력 논리가 지역 언론에게 어떻게 불리하게 작용하는지 살펴보는 연구이다. 보다 구체적으로, 지역 언론의 콘텐츠를 인용하여 네트워크 트래픽을 가져가서 수익을 올리고 지역 언론의 콘텐츠는 정작 정당한 보상을 받지 못하는 일이 빈번해지고 있는 사례를 분석했다. TV매일 신문의 원희룡 지사 부인 인터뷰에 대한 유튜브 네트워크 분석을 통해 보여줌으로써, 네트워크 미디어 권력이 지역 언론의 콘텐츠를 어떻게 소외시키는지 보여주고자 하였다. 연구 결과에 따르면, 인터뷰 영상을 인용하는 형식을 띄면서도 원본 출처를 언급하지 않거나, 실상 핵심적 내용을 보도하여 원본 영상을 찾아볼 필요가 없게 만들면서 유튜브 시청 수익을 가져가는 형태가 나타남을 알 수 있었다. 본 연구는 지역 언론의 디지털 콘텐츠 유통 전략이 기존의 네트워크 미디어 질서에서 NFT와 같은 새로운 질서를 구축할 필요성이 있음을 제기하고 있다.