• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.306-310
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• 2002

Today, corporations are approach to inside information using public network such as Internet groping economical way to utilize public network to corporation information network without buying equipment. But, special quality of internet, Virtual Private Net (VPN) that it uses net that is observed as technology that can be guaranteed public safety division transmission and data securitybecause of can not secure data transmission. In this paper. add VPN function ONU&OLT of ATM-PON system and propose SCB (Single Copy Broadcasting). When there is VPN function to ATM network, the speed can be fast, and reduce rain track pick quantity during time more. Performance analysis network simulation that use NS-2.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.783-786
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• 2015

Hole attack, which is disturbed transmission function through change of routing information, can cause critical results for MANET as non-infrastructure network. Backhole attack, as a typical hole attack, is one malicious attack which is disabled network transmission function by assumption of transmission data through modification of routing information. It is very important to evaluate transmission performance caused by blackhole attack, because transmission performance of MANET is affective with blackhole attack. In this paper, transmission performance is analyzed with MANET under multiple blackhole attacks caused multiple blackhole nodes. Computer simulation based on NS-2 is used as analysis tool and voice traffic is considered ad application service on MANET.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.637-640
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• 2011

Recently, rapid spreading of smart-phone make an expectation for increase of practical application for MANET(Mobile Ad-Hoc Network) which is not used infrastructure like as base-station. One of important application for MANET will be VoIP(Voice over Internet Protocol) known as Internet telephony. On the other hand, information intrusions causing serious problems is not allowed exception of MANET. Especially, there are some dangerous problems of intrusions to MANET, differently to other networks, because of it's usage of military purpose or emergency application of rescue. In this paper, to analyze this intrusion problem on MANET with blackhohe attacks, effect of intrusion to transmission performance is studied. VoIP traffic is assumed as an application service on MANET, computer simulation with NS-2 is used for this analysis.

• The Journal of Korean Association of Computer Education
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• v.8 no.1
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• pp.65-72
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• 2005

In this study, we suggest a new mechanism on the design and implementation of IP Traceback system against DDos/DRDoS by Zombie and Reflector attack based on spoofed IP packets. After analysis and comparing on the state-of-arts of several IP traceback mechanisms, we can find their own pros and cons primitives. And then we performed simulations on reflector based DRDoS network packets. In first, we suggest a NS-2 based IP traceback module and implement it for finding its real DRDoS attacker. As a results, we can find advanced new IP traceback scheme for providing enhanced proactive functionality against DRDoS attack.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.7
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• pp.773-778
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• 2014

IDS(Intrusion Detection System) can be used as a countermeasure for blackhole attacks which cause degrade of transmission performance by causing of malicious intrusion to routing function of networks. In this paper, effects of IDS for transmission performance based on mobility patterns is analyzed for MANET(Mobile Ad-hoc Networks), a suggestion for effective countermeasure is considered. Computer simulation based on NS-2 is used in performance analysis, VoIP(Voice over Internet Protocol) as an application service is chosen for performance measure. MOS(Mean Opinion Score), call connection ratio and end-to-end delay is used as performance parameter.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.12
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• pp.1187-1192
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• 2016

Performance analysis results are limited to of network level, because network level transmission parameters are used for performance measure and analysis of network design, construction and operation on underwater MANET, With this way of performance analysis based on network level, it is not easy to analyze transmission performance related with user level transmission quality. In this paper, transmission performance focused on application traffic be required by user is investigated to supplement weakness of performance analysis based on network level. Voice traffic, which is expected to be increasingly used on underwater MANET, is considered as application service, Some conditions for underwater MANET will be proposed to support transmission quality, MOS, CCR and EED, etc.. A computer simulation based on NS-2 is used for performance measure, voice traffic is generated as VoIP specification.

• Journal of Korea Multimedia Society
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• v.12 no.11
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• pp.1521-1529
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• 2009

There is a serious unfairness problem between upstream and downstream flows of AP in IEEE 802.11 Wireless LAN. This problem is because Wireless LAN's DCF MAC protocol provides AP with equal channel access priority to mobile noded. Also, it makes this problem worse that the TCP's Data segment loss is more effective on throughput than the TCP's ACK segment. In this paper, we first make several simulations to analysis the unfairness in the various point of view and to find reasons of the unfairness. Also, this paper presents AP's scheduling scheme to alleviate the unfairness problem and evaluate the scheme through ns2 simulator.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.289-293
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• 2011

In our previous research, we proposed a MOST GATEWAY system for organically connected to the network MOST150 and MOST 25 and we proposed a simulation design method for performance analysis of Scheduling Algorithm in MOST GATEWAY system. Therefore in this paper, after comparing the performance among the existing scheduling algorithm methods in MOST25 and MOST150 Networks, we use NS-2 simulator in order to analyze the performance. Finally, we present an improvement scheme of the efficiency and scalability.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.649-652
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• 2015

Previous marking policy for the AF service of TCP traffic in the Diffserv network have no sufficient consideration on the effect of RTT and target rate. In this paper, in order to improve fairness Index by the effect RTT difference of TCP traffic, we propose the modified TSW3CDM(Time Sliding Window Three Color Dynamic Marker) based on average transfer rate estimation and the flow state. The proposed algorithm is dynamic marking policy that do allocate band width in proportion to transmission rate. To evaluate the performance of the proposed algorithm, We accomplished a computer simulation using NS-2. From simulation results, the proposed TSW3CDM algorithm improves fairness index by comparison with TSW3CM.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.11
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• pp.1077-1082
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• 2016

IDS can be used as a countermeasure for malicious attacks which cause degrade of network transmission performance by disturbing of MANET routing function. In this paper, effects of IDS for transmission performance on MANET under grayhole attacks which has intrusion objects for a part of transmissions packets, some suggestion for effective IDS will be considered. Computer simulation based on NS-2 is used for performance analysis, performance is measured with VoIP(: Voice over Internet Protocol) as an application service. MOS(: Mean Opinion Score), CCR(: Call Connection Rate) and end-to-end delay is used for performance parameter as standard transmission quality factor for voice transmission.