• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권12호
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• pp.4389-4410
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• 2014

Network coding is a promising technology that increases system throughput by reducing the number of packet transmissions from the source node to the destination node in a saturated traffic scenario. Nevertheless, some packets can suffer from end-to-end delay, because of a queuing delay in an intermediate node waiting for other packets to be encoded with exclusive or (XOR). In this paper, we analyze the delay according to packet arrival rate and propose two network coding schemes, iXOR (Intelligent XOR) and oXOR (Optimal XOR) with Markov Decision Process (MDP). They reduce the average delay, even under an unsaturated traffic load, through the Holding-${\chi}$ strategy. In particular, we are interested in the unsaturated network scenario. The unsaturated network is more practical because, in a real wireless network, nodes do not always have packets waiting to be sent. Through analysis and extensive simulations, we show that iXOR and oXOR are better than the Distributed Coordination Function (DCF) without XOR (the general forwarding scheme) and XOR with DCF with respect to average delay as well as delivery ratio.

• 대한전기학회논문지:전력기술부문A
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• 제55권4호
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• pp.156-162
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• 2006

Transmission zones can be defined based on LMPs. Each zone consists of nodes with similar LMPs, and zonal price is determined by average nodal prices in each zone.[1] Network reduction is still important for the analysis of zonal systems under electricity market environments, even though the computing capability of computer system can deal with entire power systems. The Similarity Index is a good performance measure for the network reduction.[2] It can be applied to the network reduction between zones categorized by the nodal prices. This paper deals with a novel network reduction method between zones based on the similarity Index. Line admittances of reduced network were determined by using the least square method. The proposed method was verified by IEEE 39 bus test system.

• International Journal of Computer Science & Network Security
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• 제23권12호
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• pp.194-198
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• 2023

The current electricity networks will undergo profound changes in the years to come to be able to meet the growing demand for electricity, while minimizing the costs of consumers and producers, etc. The electricity network of tomorrow or even the intelligent « Smart Grids » network will be the convergence of two networks: the electricity network and the telecommunications network. In this context falls our work which aims to study the impact of the integration of energy decentralization into the electricity network. In this sense, we have implemented a new smart grid model where several coexisting suppliers can exchange information with consumers in real time. In addition, a new approach to energy distribution optimization has been developed. The simulation results prove the effectiveness of this approach in improving energy exchange and minimizing consumer purchase costs and line losses.

• 한국심리학회지:학교
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• 제18권2호
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• pp.175-195
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• 2021

친밀한 친구 관계를 맺고 소속감을 느끼는 것은 청소년의 심리·사회적 발달 및 적응에 긍정적인 영향을 미친다. 소속감 지향성은 소속감을 추구하는 동기로, 성장 지향성과 결핍감소 지향성으로 구분된다. 성장 지향성과 결핍감소 지향성은 심리적 적응 및 대인관계 특성에 서로 다른 영향을 주는 것으로 알려져 있다. 본 연구의 목적은 청소년의 소속감 지향성이 심리적 적응과 친구 네트워크에 미치는 효과를 알아보는 것이다. 이를 위해 한 중학교의 2학년 전체 학생을 대상으로 학기 초와 학기 말에 검사를 실시했다. 친구 네트워크는 네트워크 수신 중심성 분석을 통해 측정했다. 다층 회귀모형을 사용한 분석 결과는 첫째, 학기 초의 외로움과 스트레스에 대한 성장 지향성의 효과는 학기 초 친구 네트워크 중심성을 분석 모형에 함께 투입해도 유의했으나, 결핍감소 지향성의 효과는 유의하지 않았다. 둘째, 성장 지향성은 학기 말의 친구 네트워크 중심성을 유의하게 예측했다. 이러한 효과는 학기 초 친구 네트워크 중심성과 학기 말 심리적 적응 수준을 분석 모형에 함께 투입해도 유의했다. 셋째, 학기 말의 심리적 적응에 미치는 학기 말의 친구 네트워크 중심성의 효과는 학기 초 및 학기 말의 심리적 적응을 모형에 함께 투입해도 유의했다. 본 연구는 단기-종단적 설계를 통해 소속감 지향성이 청소년의 학기 초와 학기 말의 심리적 적응과 친구 네트워크 수준에 미치는 효과를 경험적으로 밝혔다는 점에서 의의가 있다. 끝으로, 본 연구의 한계점 및 후속 연구를 위한 제언을 논의했다.

• 디지털산업정보학회논문지
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• 제9권3호
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• pp.91-98
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• 2013

Node which plays the role of cache server does not exist in the wireless ad-hoc network consisting of only mobile nodes. Even if it exists, it is difficult to provide cache services due to the movement of nodes. Therefore, the cooperative cache technique is necessary in order to improve the efficiency of information access by reducing data access time and use of bandwidth in the wireless ad-hoc network. In this paper, the whole network is divided into zones which don't overlap and master node of each zone is elected. General node of each zone has ZICT and manages cache data to cooperative cache and gateway node use NZCT to manage cache information of neighbor zone. We proposed security structure which can accomplish send and receive in the only node issued id key in the elected master node in order to prepare for cache consistent attack which is vulnerability of distributed caching techniques. The performance of the proposed method in this paper could confirm the excellent performance through comparative experiments of GCC and GC techniques.

• 한국통신학회논문지
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• 제35권7B호
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• pp.1050-1057
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• 2010

오늘날 네트워크에 대한 침해사고가 급증하고 있으며, 점차 증가하고 있는 인바운드 네트워크에 대한 공격도 함께 증가하고 있다. 이러한 공격에 대응하기 위해서 보안시스템의 개발이 지속적으로 이뤄지고 있지만, 인바운드 네트워크의 성능 감소의 문제가 발생하기 때문에, 성능 향상과 보안성 강화를 위한 모두를 고려한 보안시스템 개발이 시급한 실정이다[1]. 따라서 본 논문에서는 네트워크를 분할하여 보안등급에 따라 관리함으로써 성능을 향상 시키기 위한 보안클러스터링을 제안하고자 한다.

• 한국컴퓨터정보학회논문지
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• 제22권4호
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• pp.75-82
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• 2017

While the internet has evolved in terms of information sharing and efficiency, it is still prone to security attacks and remains vulnerable even when equipped with a security mechanism. Repeated patching against hacks involves excessive wear of system equipment and high costs. Methods of improving network security include the introduction of security equipment and network partitions, but they have not been fully effective. A fundamental solution is the Operation Content Network (OCN), which enables the strengthening of authentication. In this paper, Instead of following the existing TCP/IP system, OCN establishes an immunity-based security system through content-centric communications. Data transmission occurs over a Content Centric Network (CCN), which is provided with a protocol verified by the CCNx group. Areas protected by OCN rely only on CCN for communication without using any IP. As such, it defends the system against unknown attacks, including zero-day attacks.

• 경영과학
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• 제11권3호
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• pp.103-128
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• 1994

Due to the trend of evolution toward a broadband communication network with fiber-optics, the design and operation of fiber-optic network have been received a great deal of research attention recently. Furthermore, even a single fiber link failure in the network may result in severe service loss. Thus, the network survivability becomes an importantissue in planning and designing the network. This survey is on modelling of various fiber-optic subscriber loop network(FSLN) design problems, which are essential ones for providing broadband communication services and B-ISDN services. Models are classified and investigated as either conventional decomposition-iteration approach or integrated design method. To build survivable networks, SHR models are also suggested by ring control schemes. The result of this study will be effectively applied to build a design model for FSLN in the practical applications.

• 산업공학
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• 제20권3호
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• pp.395-406
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• 2007

In the telecommunication industry, estimation of the cost of network facilities is very important since depreciation cost of the facilities accounts for a large portion of the product cost. Moreover, cost estimation in the industry becomes more difficult because of increasing indirect cost upon digital convergence, expanding multi-purpose facilities, complexity of service product, etc. Nevertheless, not much seem to have been done in improving estimation methodology of the cost of network facilities. As a result, the quality of cost information on network facilities has deteriorated, and now even decision-makers in the industry dismiss the information. Recently, two major telecommunication companies adopted a new network cost estimation method to deal with the issue. In this paper, we study the concept of new cost estimation method and the procedure to develop and apply it. We also suggest the method to carry out the cost allocation using Matlab which is more efficient and time-saving than other commercial cost calculation packages.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권11호
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• pp.741-746
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• 2004

When investigating a control problem for network based control systems, the main issue is network-induced delay. This delay can degrade the performance of control systems designed without considering the delay and even destabilize the system. In this paper, we consider the stabilization of network based control systems, where there is bounded time-varying delay. This delay is treated like parameter variation of a discrete time system. The state feedback controller design is formulated as linear matrix inequality. Finally, we show that the stability of control systems designed with considering the delay is superior to that is not so.