• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.202-204
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• 2005

통신 네트워크 발전 추세에 따라 데이터와 음성회선을 통합하고 PSTN을 통한 전화 서비스보다 저렴한 통신비용과 다양한 부가서비스 구현 등의 여러 장점을 가진 VoIP서비스로 전환되고 있다. 하지만 VoIP서비스의 긴급서비스에서 위치식별 대한 문제점이 제기되었다. VoIP는 인터넷망을 이용하으로 부여된 발신전화번호 정보를 송출하지 않아 발신자의 위치 및 해당지역 PSAP의 식별이 불가능하다. 이에 따라 건물 내 LAN 환경에서 VoIP 단말기와 연결하는 실내의 모든 이더넷 포트에 대한 정보를 관리하여 이를 지정된 VoIP 단말기와 연계시킴으로써 위치를 확인하는 방법 등이 제안되었으나 단말기 이동시마다 위치정보를 수정해야 하는 문제가 제기되었다. 따라서 본 논문에서는 VoIP서비스에 서 RFID를 이용하여 발신자 단말기 위치를 식별하는 긴급서비스 지원 모델을 제안하고, 이를 위해 가입자 위치정보 획득 및 관리, 호 라우팅 등에 관한 구체적인 방안을 제시하였다. 그 결과 VoIP 망에서 단말기 이동에 대한 위치 확인 문제도 해결이 가능하다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.12
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• pp.18-26
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• 2003

In this paper, we design and implement a QoS control function in the SIP-based VoIP system. As a network infrastructure for VoIP service, we select the Intserv over Diffserv architecture where the network resources are managed by a call admission control mechanism. The SIP protocol extended to support QoS signaling procedure is modulized to operate independently with the infrastructure. The performance of the QoS-enabled VoIP system is verified by experiments.

• Convergence Security Journal
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• v.10 no.3
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• pp.69-75
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• 2010

At present, deterioration in service quality, which caused by increased network traffic from a lot of users in the same network, makes smooth communication service difficult. In this paper, we present policy-based QoS management system for VoIP service in order to supply smooth VoIP service to users. The presented system can guarantee quality of VoIP service even in huge traffic situation, and makes it possible to operate whole network in an efficient manner.

• Journal of Korea Society of Digital Industry and Information Management
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• v.14 no.4
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• pp.117-125
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• 2018

Recently, VoIP technology is widely used in our daily life. Even VoIP has become a technology that can be easily accessed from services such as home phone as well as KakaoTalk.[1] Most of these Internet telephones use the RTP protocol. However, there is a vulnerability that the audio data of users can be intercepted through packet sniffing in the RTP protocol. So we want to create a tool to check the security level of a VoIP network using the RTP protocol. To do so, we capture data packet from and to these VoIP networks. For this purpose, we first configure a virtual VoIP network using Raspberry Pi and show the security vulnerability by applying our developed sniffing tool to the VoIP network. We will then analyze the captured packets and extract meaningful information from the analyzed data using the Google Speech API. Finally, we will address the causes of these vulnerabilities and possible solutions to address them.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.1
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• pp.49-54
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• 2011

In this paper, End-to-End VoIP(Voice over Internet Protocol) performance over large scale MANET(Mobile Ad-hoc Networks) is evaluated. VoIP implementation model, which can be used for large scale MANET, is suggested through this evaluation. VoIP simulator based on NS-2 network simulator is used for performance measurement. Call connection ratio as a connection performance, MOS and network delay as a transmission performance, packet loss rate as other performance is measured with this simulation. Finally, maximum $10{\sim}15km^2$ as a single MANET, 500 nodes and 100 call connections is suggested for VoIP implementation and operation conditions over large scale MANETs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6A
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• pp.558-564
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• 2007

3G Long Term Evolution, which aims for various mobile multimedia service provision by enhanced wireless interface, proposes VoIP-based voice service through a Packet Switching (PS) domain. As delay and loss-sensitive VoIP traffic flows through the PS domain, more challenging technical difficulties are expected than in Circuit Switching (CS) domain based VoIP services. Moreover, since 3G LTE, which adopts the OFDM as its physical layer, introduces Physical Resource Block (PRB) as a unit for transmission resources, new types of resource management schemes are needed. This paper proposes a PRB scheduling algorithm of MAC layer for VoIP service in 3G LTE and shows the simulation results. The proposed algorithm has two key parts; dynamic activation of VoIP priority mode to satisfy VoIP QoS requirements and adaptive adjustment of the priority mode duration in order to minimize the degradation of resource utilization.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.277-280
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• 2011

VoIP is a technology of voice communication, using the existing internet network which sends and receives voice packets. VoIP has an advantage that VoIP is cheaper than an existing telephony, and the tech is vitalized lately. But recently you can download Volp Application in the Market that have a vulnerability(Anyone Can Upload). This weakness is wrongfully used that People are downloaded by encouraging about malignant code is planted. Signal intercepts indicates from this case. and paralysis by DDoS Attack, bypass are charged for hacking. Judging from, security threat of VolP analysis and take countermeasures. In the thesis we analyze the VoIP security caused on 'Soft Phone' and 'Smart Phone', and figure out security policies and delineate those policies on the paper.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.16-18
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• 2009

VoIP(Voice over IP) is the technology to transport voice and video over IP networks such as Internet. Today, VoIP technology is viewed as the right choice for provide voice, video, and data communication over next generation network. We are sure that the multipoint VoIP will help enhancing the various application services in ubiquitous environment. The paper shows multipoint VoIP system implemented with end-point mixing model and introduces various embedded systems such as UFC(Ubiquitous Fashionable Computer), tourist guide terminal and industrial terminal which use the multipoint VoIP.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.719-721
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• 2010

VoIP over MANET is an important IP phone technique used in mobile ad-hoc networks. VoIP system over wired networks is based on SIP, SIP UA and SIP server which process the users invite, register and so on. Since no base stations in MANETs to perform as SIP servers, VoIP service on MANETs is being done with tiny SIP server which is done on each node. In this paper, VoIP system is implemented with pseudo SIP server which can process 1 call based on modification of standard SIP server which is used on communication environment such as wired networks. The propesed system is performed well and compatible with SIP and SIP UA.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.431-433
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• 2010

VoIP is a communication technique can be used anywhere you can find wifi signal and it costs much lower than conventional mobile service. However, security of VoIP is not as robust as former, the converse could be easily intercepted and attacked especially in MANETs which the attackers access easier than in wired networks. Sercurity of VoIP system in MANETs is an important issue nowadays. In this paper, a typical attack method of VoIP systems in MANETs is described and we implement how to prevent it.