• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.279-281
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• 1998

기존 이동통신 시스템은 단말 및 개인 이동성의 결여, 저조한 데이터 전송율, 그리고 서비스 도입 및 호환성의 어려움이 존재한다. 이를 해소하기 위해 국제적으로 차세대 이동통신 시스템으로 IMT-2000에 대한 연구와 개발이 이루어지고 있다. 또한 IMT-2000은 기본적으로 지능망에 근간한 구조를 지향하며, 다양한 서비스들의 실현 및 신속한 도입을 위하여 지능망이 IMT-2000의 기능 모델 표준으로 채택되고 있으며. 이를 기반으로 다양한 서비스가 개발되고 있다. 한편 IN CS-2의 목표서비스(target service) 의 하나로서 가상 사설망 서비스는 기존 사설망의 독립적인 망 운영을 유지하면서, 공중망의 자원을 이용하여 기존 사설망의 과다한 초기 투자 비용을 해소시키는 장점을 제공한다. 본 논문은 IMT-2000의 서비스 제어를 위해 IMT-2000의 망 구종에 도입된 지능망 모델을 분석하고 IMT-2000상에서 특히 기존 고정/이동 통신망과 달리 기본적으로 제공되는 개인 이동성을 고려하여 지능망의 서비스 제어 모델에 따라 가상 사설망 서비스를 설계한다.

• Journal of the Korea Society of Computer and Information
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• v.15 no.8
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• pp.67-78
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• 2010

Various services such as IPTV, VoIP, multimedia over IP, on-line payment, on-line game, etc. were made possible due to the rapid advance of the network. In order to provide secure and seamless services over the network, the Internet service providers are performing continuous network monitoring using NMS. The main function of NMS is to perform a diagnosis to identify the potential causes of failure from event messages. In this paper, a simulation tool, named as NetDoctor, is presented which is capable of identifying and diagnosing the potential problems in the virtual network, before the network model is constructed. In NetDoctor, a series of various and artificial failure is imposed on the virtual network, and it was analyzed if NetDoctor could identify the problems. The experimental results on virtual network show that the developed tool is very effective in identifying and diagnosing the problems. The presented simulation tool can be used in the design of robust network.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.10
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• pp.1101-1108
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• 2015

In this paper, to provide a method and system for providing a network separation virtual machine environment. How to provide this virtual machine environment include phase generating necessary virtual resource requirement for the perform of virtual function and transfer to network changing protocol about request of registration virtual resource. For this reason, Registration procedure is to use a virtual machine for a virtual computing resource allocation and separation combined network any time, it became possible between servers and clients, or mobile phone. At any time, it is possible to process the work in the same environment as in a computer to access the Internet.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.10a
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• pp.328-328
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• 1994

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10b
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• pp.1481-1484
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• 2000

기존의 사설망에서 쉽게 제공될 수 있었던 QoS가 가상 사설망에서는 새로운 패러다임을 요구하게 되었다. 가상 사설망이 고려되고 구현되는 형태가 다양한 만큼 보안이 아닌 QoS도 여러 가지 형태의 VPN에서 고려되고 있다. 본 논문에서는 보안성과 QoS보장 모두를 제공할 수 있는 방법들에 대해서 살펴보고 요즘에 크게 대두되고 있는 MPLS VPN 기법에 대해서 기술하고 개선되어야 할 점들에 대해서 논의한다.

• Journal of Korean Society for Geospatial Information Science
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• v.12 no.1 s.28
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• pp.55-62
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• 2004

More recently, multiple reference based RTK GPS techniques(VRS ; Virtual Reference System) are becoming increasingly important for many precise GPS applications in many countries to overcome the constrained distance limitations of standard RTK systems. The precision of the position solutions of the rover receiver is closely connected with that of the corresponding virtual reference points(VRPs). The objective of this paper is to investigate the accuracy and performance of the VRPs on the test network have been made in post mode, and the overall analysis results were presented by comparing the solutions for the VRPs from the existing GPS reference station with the true values of the coordinates used to produce the observation data. The results show the reasonable accuracies of VRPs in the network area by using the VRS concept in post mode.

• Journal of Korea Multimedia Society
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• v.7 no.11
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• pp.1580-1587
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• 2004

Nowadays, VPN(Virtual Private Network) devices supporting multi-link connections only utilize the second link to backup the fail-off primary link. In practice, however, the occurrence of the link fail-off is so rare that the capacity available on the second link is wasted. In this paper, a scheme of establishing a VPN with multi-links, and load balancing between the links under normal circumstances is proposed in order to take advantage of multi-links, and to eventually increase the effective bandwidth of the VPN. Additionally, the transition functionality is also applied for the link fail-off case like existing VPN devices. Consequently, the proposed scheme enables VPNs with multi-links not only to maintain the higher availability but also to highly increase the effective bandwidth.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5C
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• pp.519-533
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• 2006

The number of channels specified in IEEE 802.15.4 Low-Rate Wireless Personal Area Networks(LRWPANs) is too few to operate many applications of WPANs in the same area. To overcome this limit, we introduce Virtual Channel, a novel concept to increase the number of available channels when various WPAN applications coexist. Basically, a virtual channel is a newly-created channel via superframe scheduling within the inactive period of a logical channel preoccupied by other WPANs. To maximize the coexistence capability of WPANs using virtual channels, we propose Least Collision superframe scheduler(LC-scheduler), its less complex heuristics both for a given single channel, and Virtual Channel Selector(VCS) to efficiently manage multiple available logical channels. In addition, a simple but practical synchronization method is developed to compensate different time drifts among coexisting WPANs. The simulation results demonstrate that a remarkable improvement on the coexistence capability of the 802.15.4 can be achieved through the proposed schemes.

• Journal of Digital Convergence
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• v.13 no.5
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• pp.169-176
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• 2015

Virtual Private Network is a method which can use as a private network using private line. The quality of security of virtual private network is influenced by security auditability, cryptographic support, user data protection, access control, etc., and efficiency is influenced by throughput, latency, the number of cession, etc. In this paper, we constructed a evaluation model based on CC(ISO/IEC 15408) and the quality evaluation standard ISO/IEC 25000 series to evaluate the quality level about efficiency with security performance of virtual private network. We think that this study will contribute to construct the system which can evaluate the quality of virtual private network based on CC and ISO quality evaluation standard.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.8
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• pp.1071-1076
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• 2020

The importance of network separation is due to the use of the Internet with existing business PCs, resulting in an internal information leakage event, and an environment configured to allow servers to access the Internet, which causes service failures with malicious code. In order to overcome this problem, it is necessary to use network virtualization to separate networks and network interconnection systems. Therefore, in this study, the construction area was constructed into the network area for the Internet and the server farm area for the virtualization system, and then classified and constructed into the security system area and the data link system area between networks. In order to prove the excellence of the proposed method, a network separation construction study using network virtualization was conducted based on the basis of VM Density's conservative estimates of program loads and LOBs.