• Journal of KIISE:Information Networking
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• v.32 no.4
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• pp.495-507
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• 2005

Measuring the end-to-end available bandwidth in the Internet is a useful tool for distributedapplication services or QoS (Quality-of-Service) guarantee. To measure the end-to-end available bandwidth, Single-hop Gap model-based packet train measurement techniques are well-known. However, the error of packet train output gap can happen by network topologies. This error of the output gap causes the inaccuracy of the available bandwidth measurement. In this paper, we propose a new end-to-end available bandwidth measurement technique with accurate capacity measurement and fast convergence methods. To solve the erroneous capacity measurement problem of the back-to-back packet train transmission, we propose a new available bandwidth measurement method by decoupling the capacity measurement with the initial gap of the packet train. Also, we propose a new technique to predict the proper initial gap of the packet train for faster convergence. We evaluate our proposed method by the simulation in various topologies comparing with previous methods.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.621-624
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• 2017

In this paper, we propose a protocol synchronizing to packet trains in a underwater acoustic networks with limitations such as long propagation delay, low data rate, high packet loss. The proposed protocol employs an one-way communication scheme to calculate packet arrival time differences of consecutively transferred packets and minimizes uncertain variation effect of long propagation delay. Simulation results shows the superiority of our protocol, compared with a previously proposed one under the given network conditions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.113-115
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• 2017

패킷트레이서는 라우터/스위치 등 네트워크 장비를 가상으로 구성하고 각 장비의 CONFIG를 세팅, 실습 할 수 있는 프로그램이다. 고객의 요구를 받아서 중소규모 네트워크의 보안설정을 추가하여 보다 높은 안정성과 효율성 있는 네트워크를 구성하고 고객의 정보를 DB서버에 저장하여 DB서버에 접근시 데이터를 불러 올수 있도록 한다. 이 논문에서는 중소규모 병원 네트워크 인프라 구축을 위한 방안을 제시한다. 부서별로 스위치를 한대씩 배치하고 외부기관은 멀티포인트 프레임릴레이를 설정하여 전용회선으로 만들어 사용한다. 각종개인정보가 들어있는 DB는 외부에 두고 보안기능을 넣어서 신뢰성을 향상시킨다. 단순히 네트워크 구축뿐만 아니라 DB를 연동하여 정보를 저장하고, 보안 기능을 넣어서 네트워크의 취약점을 보안하고자 한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.68-71
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• 2018

In this paper, we propose a synchronization protocol for underwater acoustic networks which aims to minimize the effects of long propagation delay and uncertain delay variations and employs packet train scheme with considering low data rate. The proposed protocol uses an one-way delay measurement method by transmitting consecutive packets and acquires synchronization only considering propagation delay variations by calculating packet arrival time differences. We perform simulations under various network conditions, such as node mobility, time interval for packet transmission, network range, and elapsed time after synchronizing. The simulation results shows the superiority of our protocol, compared with a previously proposed protocol.

• Proceedings of the Korea Contents Association Conference
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• 2010.05a
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• pp.408-410
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• 2010

인터넷에서 단대단 (end-to-end) 가용대역폭 측정은 분산된 응용서비스, 단대단 QoS 보장, 오버레이 네트워크에서의 경로설정, SLA (Service Level Agreements), 분산 네트워크, 지능적인 라우팅 시스템, 비디오/오디오 스트리밍 시스템에서 다양한 연구가 진행되고 있다. 일반적으로 단대단 가용대역폭 측정기법으로 단일-홉-갭 모델에 기반한 패킷 트레인(packet train) 전송을 통하여 가용대역폭을 측정하는 기법과, 각각의 패킷의 전송률을 높여가며 수신측에서의 지연시간(Queueing Delay)를 분석하여 가용대역폭을 측정하는 자가 혼잡 유발(SLoPS : Self-Loading Periodic Stream) 기법이 있다. 본 논문에서는 자가 혼잡 유발 기법을 이용하여 가용대역폭 측정 방안을 제안한다.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.2
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• pp.295-300
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• 2017

AAA, an information-protective protocol authorizes the degree of service and rights to the user through a safe and reliable authentication. The protocol also systematically manages the accounting functions including billing, monitoring, and reporting using the user information. After a topology was created to design a network based on a router and server using RADIUS and TACACS+, a common virtual network was made using a packet tracker. This paper presents cases showing valid authentication through simulations.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.5
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• pp.491-498
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• 2016

An ACL(: Access List), a list that determines network access, is used for the security of the network. An ACL if applied to a interface of router can filter particular packets. Also it can block or allow the access of certain unauthorized IPs or ports, based on the source address, destination address, and TCP/UDP port. This paper presents a simulation case to verify the effect of a router-based network applying Standard ACL or Extended ACL. The network was created through designing topology and then making a common virtual network using a Packet Tracer.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.10
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• pp.1131-1138
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• 2015

As the size of the internet market grows rapidly, the number of IPv4 addresses available is being exhausted, while transition to IPv6 is being delayed. As the best alternative solution, Network Address Translation(NAT) scheme is being used. It connects the public internet network with the private internet network in order to reduce the waste of IPv4 addresses space. The purpose of this paper is to study the effective example of network based on common virtual network using Packet Tracer with topology designed rather than usual theoretical approach in Dynamic NAT and PAT, which allows more efficient use of address space.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.10
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• pp.1003-1008
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• 2016

Recently hospitals have divided into many divisions, specialized the medical service, and shown organic cooperation, all to provide patients with various and high quality medical service. They have also showed improvement in information protection by introducing an information protection system to regulate the access to patients' medical and personal information. The purpose of this paper is to present a case study to implement of a limited hospital medical information system that can regulate the access to medical information. For this, a router-based virtual network applying an ACL(: Access Control List) to regulate access to information was made using a packet tracer.

• Journal of the Korea Society of Computer and Information
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• v.6 no.1
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• pp.67-73
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• 2001

This paper proposes a new scheduling algorithm for broadband ATM access network. The existed scheduling algorithms (Train, Chao. Dynamic scheduling algorithm) have high cell loss rate and waste channel. These proposed mechanism utilize to control of multimedia services based on the quality of service level of the input traffic This paper suggests a functional architecture of scheduling and the scheduling algorithm to satisfy various QoS requirements. The performance measures of interest, namely steady-state cell loss probability and average delay, average delay, are discussed by simulation results.