• The Korean Journal of Physiology and Pharmacology
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• 제16권3호
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• pp.199-204
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• 2012

We evaluated the role of Tat-mediated p66shc transduction on the activation of endothelial nitric oxide synthase in cultured mouse endothelial cells. To construct the Tat-p66shc fusion protein, human full length p66shc cDNA was fused with the Tat-protein transduction domain. Transduction of TAT-p66shc showed a concentration- and time-dependent manner in endothelial cells. Tat-mediated p66shc transduction showed increased hydrogen peroxide and superoxide production, compared with Tat-p66shc (S/A), serine 36 residue mutant of p66shc. Tat-mediated p66shc transduction decreased endothelial nitric oxide synthase phosphorylation in endothelial cells. Furthermore, Tat-mediated p66shc transduction augmented TNF-${\alpha}$-induced p38 MAPK phosphorylation in endothelial cells. These results suggest that Tat-mediated p66shc transduction efficiently inhibited endothelial nitric oxide synthase phosphorylation in endothelial cells.

• 한국자기공명학회:학술대회논문집
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• 한국자기공명학회 2002년도 제20회 학술발표회
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• pp.26-26
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• 2002

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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• pp.2011-2012
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• 2006

전력선 채널의 특성을 대표하는 배경 잡음과 전기기기에서 발생하는 충격잡음은 실증 시험을 통해 측정되거나 매체 자체의 특징을 수학적 기법을 통해 모델링하는 두 가지의 방법이 있다. 여타의 통신 시스템과 마찬가지로 채널에 대한 정확한 정보제공이 수신기의 성능 분석 및 향상을 가능케 한다. 최근 전력선 채널의 배경잡음이 무선통신 채널의 Nakagami-m 분포를 따른다는 측정결과가 발표되었다. 본 논문에서는 Nakagami-m 분포를 배경잡음으로 전력선 채널 모델링한 경우 평균값 등의 통계적 특성을 제공함으로서 수신기의 성능 분석 및 향상에 기여하고자 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권8호
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• pp.3701-3727
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• 2016

Recently Service Function Chaining (SFC) is promising to innovate the network service mode in modern networks. However, a feasible implementation of SFC is still difficult due to the need to achieve functional equivalence with traditional modes without sacrificing performance or increasing network complexity. In this paper, we present a configurable network service chaining (CNSC) mechanism to provide services for network traffics in a flexible and optimal way. Firstly, we formulate the problem of network service chaining and design an effective service chain construction framework based on integrating software-defined networking (SDN) with network functions virtualization (NFV). Then, we model the service path computation problem as an integer liner optimization problem and propose an algorithm named SPCM to cooperatively combine service function instances with a network utility maximum policy. In the procedure of SPCM, we achieve the service node mapping by defining a service capacity matrix for substrate nodes, and work out the optimal link mapping policies with segment routing. Finally, the simulation results indicate that the average request acceptance ratio and resources utilization ratio can reach above 85% and 75% by our SPCM algorithm, respectively. Upon the prototype system, it is demonstrated that CNSC outperforms other approaches and can provide flexible and scalable network services.

• ETRI Journal
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• 제27권3호
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• pp.334-336
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• 2005

We improved the performance of the spectrum-sliced light source for wavelength-division-multiplexed passive optical networks by employing a Fabry-Perot laser diode(FP-LD). We found that the FP-LDs can suppress the intensity noise as significantly as using a gain-saturated semiconductor optical amplifier. The transmission characteristics were measured and analyzed in both conditions with and without employing an FP-LD.

• ETRI Journal
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• 제35권3호
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• pp.414-424
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• 2013

We consider a new load balancing routing for delay-guaranteed services in the network in which the traffic is dynamic and network topologies frequently change. For such an ever-changing network, we propose a new online load balancing routing called AntLBR, which exploits the ant colony optimization method. Generally, to achieve load balancing, researchers have tried to calculate the traffic split ratio by solving a complicated linear programming (LP) problem under the static network environment. In contrast, the proposed AntLBR does not make any attempt to solve this complicated LP problem. So as to achieve load balancing, AntLBR simply forwards incoming flows by referring to the amount of pheromone trails. Simulation results indicate that the AntLBR algorithm achieves a more load-balanced network under the changing network environment than techniques used in previous research while guaranteeing the requirements of delay-guaranteed services.

• Journal of information and communication convergence engineering
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• 제9권5호
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• pp.523-529
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• 2011

In this paper an inter-layer protocol, referred to as a Multi-Network Selector (MNS) is proposed for multiband maritime networks. A MNS is located between the data-link layer and the network layer and performs vertical handover when a ship moves another radio network. In order to provide seamless data transfer to different radio networks, the MNS uses received signal strength (RSS) and ship's location information as decision parameters for vertical handover, which can avoid ping-pong effect and reduces handover latency. In addition, we present related issues in order to implement the MNS for a multiband maritime network.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.321-322
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• 2008

CSS(Chirp Spread Spectrum) technology adopt SDS-TWR algorithms of TOA(Time of Arrival) using velocity of specific medium and ToF(Time of Flight) to measure a distance, but this method always has a regular error on distance regardless of a real distance, as a result, in far distance, it decrease a error on distance relatively, but in near distance, it increase a error on distance relatively. in this paper, we propose and test new method measuring a distance more precisely in near distance using CSS and RSSI

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2021년도 제64차 하계학술대회논문집 29권2호
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• pp.117-122
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• 2021

In order to reveal the co-research relationship with key research institutes in the computer field in Korea, which have high competitiveness in the ICT field, this paper analyzes the co-author network of research institutes based on the papers of Korean journals. For this study, 15 computer journals published in Korea were selected and collected for the past 5 years. In addition, authors, affiliated institutions, and country information were extracted from the papers, and experimental data were produced using institutional identification data and SNA analysis techniques. Through this, statistical analysis was performed on researchers, research institutes, and countries, and the centrality of research institutes was measured through co-authored network analysis and visualized as a map. The results of the research that analyzed the co-author relationship based on the papers in computer science journals published in Korea are as follows. First, the status of co-author relations among researchers was statistically analyzed in detail. The number of authors, the number of co-authors, and statistics by co-authoring countries, as well as the ratio of co-authored research by institution and the ratio of co-authored by country were revealed. The co-authoring status of papers in English journals was analyzed separately to compare and analyze characteristics. Second, the centrality of each individual was measured through the co-authored network analysis of the identified researchers, institutions and countries affiliated with the institution, and the frequency of connection between data by level was identified. In addition, the co-authorization network between research institutes was visualized and presented as a map so that the overall view of the co-authoring network was presented, and the connection frequency between the institutes was checked. It is possible to recommend a research partner based on the co-authoring behavior of Korean computer researchers and the co-authoring relationship between major research institutes. For this, additional research is needed to analyze the subject areas of each institution.

• 한국멀티미디어학회논문지
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• 제19권8호
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• pp.1487-1497
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• 2016

Explosively growing service of digital multimedia data increases the need for highly scalable low-cost storage. This paper proposes the new storage architecture based on torus network which does not need network switch and erasure coding for efficient storage usage for high scalability and efficient disk utilization. The proposed model has to compensate for the disadvantage of long network latency and network processing overhead of torus network. The proposed storage model was compared to two most popular distributed file system, GlusterFS and Ceph distributed file systems through a prototype implementation. The performance of prototype system shows outstanding results than erasure coding policy of two file systems and mostly even better results than replication policy of them.