• Journal of Korea Multimedia Society
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• v.14 no.5
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• pp.658-668
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• 2011

Over the past decade, the improvement of communications technologies and the rapid spread of www (World Wide Web) have brought on the exponential growth of users using Internet and real time multimedia multicast services like video conferencing, tele-immersive virtual reality, and Internet games. The dense-wavelength division multiplexing (DWDM) networks have been widely accepted as a promising approach to meet the ever-increasing bandwidth demands of Internet users, especially in next generation Internet backbone networks for nation-wide or global coverage. A major challenge in the next generation Internet backbone networks based on DWDM technologies is the resolution of the multicasting RWA (Routing and Wavelength Assignment) problem; given a set of wavelengths in the DWDM network, we set up light-paths by routing and assigning a wavelength for each connection so that the multicast connections are set-upped as many as possible. Finding such optimal multicast connections has been proven to be Non-deterministic Polynomial-time-complete. In this paper, we suggest a new heuristic multicast routing and wavelength assignment method for multicast sessions called DVS-PMIPMR (Differentiated Virtual Source-based Priority Minimum Interference Path Multicast Routing algorithm). We measured the performance of the proposed algorithm in terms of number of wavelength and wavelength channel. The simulation results demonstrate that DVS-PMIPMR algorithm is superior to previous multicast routing algorithms.

• Journal of Internet Computing and Services
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• v.22 no.6
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• pp.129-140
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• 2021

The next generation mBcN should be built to cooperate with the wireless network to support hyper-speed and hyper-connectivity. In this paper, we propose a network architecture for the cooperation mBcN and 5G commercial network and architecture of the cooperative security gateway required for the cooperation. The proposed cooperative security gateway is between gNB and UPF to support LBO, SFC, and security. Our analysis shows that the proposed architecture has several advantages. First of all, user equipment connected with the mBcN can be easily connected through the 5G commercial radio network to the mBcN. Second, the military application traffic can be transmitted to mBcN without going through the 5G core network, reducing the end-to-end transmission delay without causing the traffic load on the 5G core network. In addition, the security level of the military application can effectively be maintained because the user equipment can be connected to the cooperative security gateway, and the traffic generated by the user equipment is transmitted to the mBcN without going through the 5G core network. Finally, we demonstrate that LBO, SFC, and security modules are essential functions of the proposed gateway in the 5G test-bed environment.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.36-39
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• 2013

본 논문에서는 차세대 스마트 TV 환경에서의 적응형 멀티스크린 서비스 시스템 구조를 제안하고, 이를 실제 스마트 TV 에 적용 가능하도록 프로토타입 시스템으로 구현한 결과를 보여준다. 제안 시스템은 적응형 콘텐츠 부호화 기술과 하이브리드 네트워크 전송 기술, 멀티스크린 서비스 발견 및 제어 기술을 포함하고 있다. 스마트 TV 를 중심으로 다양한 종류의 멀티스크린 장치가 연결되는 서비스 소비환경에 적응적인 콘텐츠를 제공하기 위해서 H.264/SVC 기반의 다계층 비디오 부호화/복호화 기법을 적용하였다. 또한, 다계층 부호화된 콘텐츠를 방송망과 인터넷 등 이종 멀티네트워크를 이용해 동시에 전송함으로써, 전송 대역의 가용성을 확장하는 하이브리드 네트워크 기반의 미디어 전송 기술과 UPnP 기반의 사용자 중심 멀티스크린 서비스 발견 및 이동기술을 제안한다. 기존의 멀티스크린 서비스가 단말의 소비환경에 비 적응적이고, 홈 네트워크 환경 및 플랫폼 폐쇄적인 환경에서 제공되는 단방향 멀티스크린 서비스인 반면, 본 논문에서 제안하는 적응형 멀티스크린 서비스 시스템은 네트워크 및 단말의 소비환경에 적응적이고 효과적인 웹 기반의 양방향 멀티스크린 서비스를 제공할 수 있다.

• The Journal of Korean Association of Computer Education
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• v.9 no.1
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• pp.97-106
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• 2006

In the next-generation Internet backbone network, DWDM technology was appeared as an alternative to solve circuit shortage of existing TDM-based Internet. In this DWDM Network, it is inevitable to consider wavelength-conversion function as well as RWA in case of setting up connection for the efficient use of resources and customer satisfaction. This study is to describe an efficient strategy for the wavelength-conversion function with a limited range and for the use of a wavelength converter with the selected node, and to verify the optimum use of a wavelength converter through the performance test.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.4
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• pp.639-653
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• 2013

Smart grid is a network of computers and power infrastructure that monitor and manage energy usage efficiently. Recently, the smart grid demonstration projects around the world, including the United States, Europe, Japan, and the technology being developed. The protection of the many components of the grid against cyber-threats has always been critical, but the recent Smart grid has been threatened by a variety of cyber and physical attacks. We model and analyze advanced metering infrastructure(AMI) in smart grid. Using attack countermeasure tree(ACT) we show qualitative and probabilistic security analysis of AMI. We implement using SHARPE(Symbolic Hierarchical Automated Reliability and Performance Evaluator) tool and calculate probability, ROA, ROI, Structure Importance, Birnbaum Importance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.1
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• pp.18-25
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• 2013

In this paper, we propose a self-optimization scheme for indoor femtocell coverage in heterogeneous networks. If the femtocell coverage is larger than indoor area, neighbor cell users passing by the outer area of the femtocell coverage may request an unnecessary handover which incurs wasteful signaling overhead. On the other hand, if the coverage is smaller than the indoor area, some of indoor users might not be connected to the indoor femtocell. Therefore, we propose the method by which the femtocell coverage attains the exact indoor area employing self-organized scheme. Autonomous self TX power adjustment of the femtocell is possible because the proposed method utilizes handover request events and membership information of users that can be obtained by the femtocell itself. We show that the TX power obtained by the proposed algorithm converges to the optimal TX power that can be obtained analytically to attain the indoor coverage area.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6B
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• pp.1165-1173
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• 1999

In order to support various multimedia communication services, a well balanced backbone network should be designed using recently advanced optical communication technologies. In this paper an optimal backbone network configuration design is presented fur Korean traffic environment. A new traffic model, Population-Distance-Gross Group Products(PDG) traffic model, is devised. In Korean network traffic environment, six regional centers are selected, link capacities between the regional centers are estimated from the PDG traffic model, and the overall network configuration is designed for the all-optical backbone network in Korea. A simulation study is carried out to verify the desired performance of the designed backbone network. Simulation results show that performance of the backbone network is well balanced to support various communication services in Korea in the 2000s.

• Journal of Korea Multimedia Society
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• v.14 no.1
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• pp.33-43
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• 2011

Routing technologies considering QoS-based hypermedia services have been seen as a crucial network property in next generation optical Internet (NGOI) networks based on IP/dense-wavelength division multiplexing (DWDM). The huge potential capacity of one single fiber. which is in Tb/s range, can be exploited by applying DWDM technology which transfers multiple data streams (classified and aggregated IP traffics) on multiple wavelengths (classified with QoS-based) simultaneously. So, DWDM-based optical networks have been a favorable approach for the next generation optical backbone networks. Finding a qualified path meeting the multiple constraints is a multi-constraint optimization problem, which has been proven to be NP-complete and cannot be solved by a simple algorithm. The majority of previous works in DWDM networks has viewed heuristic QoS routing algorithms (as an extension of the current Internet routing paradigm) which are very complex and cause the operational and implementation overheads. This aspect will be more pronounced when the network is unstable or when the size of network is large. In this paper, we propose a flooding-based unicast and multicast QoS routing methodologies(YS-QUR and YS-QMR) which incur much lower message overhead yet yields a good connection establishment success rate. The simulation results demonstrate that the YS-QUR and YS-QMR algorithms are superior to the previous routing algorithms.

• Journal of Broadcast Engineering
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• v.26 no.6
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• pp.758-765
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• 2021

Recently, various research on the application of deep learning to video encoding for enhancing coding efficiency are being actively studied. This paper proposes a deep learning based intra prediction which uses multiple models by extending Matrix-based Intra Prediction(MIP) that is a neural network-based technology adopted in VVC. It also presents an efficient learning method for the multi-model intra prediction. To evaluate the performance of the proposed method, we integrated the VVC MIP and the proposed fully connected layer based multi-model intra prediction into HEVC reference software, HM16.19 as an additional intra prediction mode. As a result of the experiments, the proposed method can obtain bit-saving coding gain up to 0.47% and 0.19% BD-rate, respectively, compared to HM16.19 and VVC MIP.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.7
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• pp.1354-1362
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• 2015

Heterogeneous network technology is expected to be a core technology for 5G mobile communications. 5G mobile network would be composed of many base stations even have mobility, then the operator should connect base stations through the wireless backhaul technology. This paper presents Ultra Wide Area Wireless Backhaul Network System with massive array antenna. We conducted link budget analysis for Ultra Wide Area Wireless Backhaul Network and performance analysis of massive array antenna system through the transmission simulator based on beamforming technology. In wide area ($10km^2$) wireless backhaul system composed of massive antenna, we achieved 5 bps/Hz average spectral efficiency with 1 W transmission power per beam.