• Journal of information and communication convergence engineering
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• v.6 no.1
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• pp.64-67
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• 2008

VoIP is vulnerable to attack since it uses the Internet to which many people connect simultaneously. In this paper, we designed and implemented a Wireless VoIP + VPN system with which secure telephone calls are possible using the open project SIP VoIP Gateway, 'Asterisk' and 'OpenVPN'.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.58-62
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• 2001

본 논문에서는 IMT-2000 통신방식 중 cdma-2000 방식의 시스템을 이용하여 이동통신 단말기 RF System에 미치는 위상 잡음의 영향성을 분석하였다. cdma-2000의 표준안인 TIA/EIA에서 권고한 IS-98-C 를 기초로 하여 위상 잡음 특성의 요구 조건을 유도하였다. 현재 상용화 된 부품을 이용하여 RF 시스템을 설계하여 위상 잡음 특성을 분석하였고 시스템에 가장 큰 영향을 미치는 oscillator의 위상 잡음의 양을 변화시켜 시스템에 미치는 영향을 Constellation Diagram과 Eye Diagram으로 제시 하였다.

• 한국IT서비스학회:학술대회논문집
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• 2009.05a
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• pp.380-383
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• 2009

QOOK 인터넷전화는 BcN(Broadband Convergence Network) IMS(IP Multimedia Subsystem)기반으로 음성/영상 전화를 제공한다. 본 논문에서 소개하는 QOOK 부가서비스인 한글로서비스는 인터넷 전화기를 이용하여 착신자 전화번호를 눌러 발,착신자간에 통화가 이루어지는 것이 아니라 전화번호를 모르더라도 한글이름을 입력하여 발,착신자간에 통화가 이루어지는 서비스이다. 본 논문은 일반 전화번호기반의 통화서비스에서 진화되어 전화번호가 아닌 한글이름을 이용하여 발신, 착신을 위한 BcN_소프트스위치, 응용서버 등에서 입력된 이름을 처리하는 기능을 소개한다.

• Journal of Distribution Science
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• v.17 no.6
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• pp.15-23
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• 2019

Purpose - This study evaluates the effects of e-marketing communication on brand loyalty in the mobile communication market in Kosovo. given that no prior studies of this nature are found. It explores the relationships, between e-marketing communication, brand image and customer satisfaction, and their impact on the brand loyalty. Research design, data, and methodology - The research model of four constructs was developed. The data was collected via online surveys, 423 completed surveys from mobile subscribers were received. To test the relationship between the individual variables and multiple variables with the dependent variable several test were performed including data validity and reliability, bivariate correlation, simple linear and multiple regression analysis using stepwise method. Results - Positive significant effect of e-Marketing communication on brand loyalty, as well its significant effect on both brand image and customer satisfaction, which subsequently have significant impact on brand loyalty as it was confirmed by previous studies. Conclusions - The findings confirm that e-Marketing communication is key factor in building well perceived brand image, fostering customer satisfaction, and leading to customer commitment and loyalty towards brands of mobile operators in Kosovo.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.3
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• pp.399-403
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• 2001

The existent number system, which is divided into two, will give much obstacle to achieve Information and Communication exchange between south and north korea. Therefore as a long point of view, As the number system between two koreas have to meet the communication demand and the service development. It is very important to set up the most effective and suitable structure and system in given communication environment. To prepare the future its growth as the advent of new network and communication service, This paper presents the scheme of a number system unification which is essential in the unification of Information and communication between two countries after Korea-unification.

• Journal of Digital Convergence
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• v.10 no.6
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• pp.259-267
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• 2012

Internet telephony is an Internet service which supports voice telephone using VoIP technology on the IP-based Internet. It has some advantages in that voice telephone services can be accompanied with multimedia services such as video communication and messaging services. Recently, the introduction of smart phones has led to a growth in social networking services and thus, the research and development of Internet telephony has been actively progressed and has the potential to become a replacement for the telephone service that is currently being used. In this paper we designed and implemented an Internet telephony network system which is developed by using Asterisk and open source softwares. It is developed on the linux system and has some features such as VoIP telephony service between SIP phones, voice mail, and call recording. It also supports web-based functions such as SIP users and server system management that is implemented by Apache web server and PHP programs. Afterwards, this system will be applied as VoIP network base technology for small sized companies and organizations. It will paly a role for encouraging companies to use open source softwares.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.127-133
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• 2009

It has been 10 years long since the emergence of Dialpad, the first commercial VoIP service from Saerome Technology launched on 1999. In spite of so many research papers and implementations of the VoIP and commercial services with hundreds of VoIP-related products vendors and tens of VoIP service providers during the last decade, the resulting market share of the VoIP callings at the year 2007 in Korea is just about 0.3%, which is extraordinary lower one than expected. There have been proposed several facts for the reason including the QoS issue and the incomplete governing system. In this paper we suggest that the reason is based on the sociocultural issue and further we assert and verify that it can never replace the existing legacy telephone system for the current VoIP service model, as long as the telecommunication companies continue the legacy telephone service. We also suggest the another choice, to upgrade the concept of the current VoIP service to a new paradigm based on SIP and presence service, while letting the legacy telephone system be as it is.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.197-200
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• 2013

Internet phone, communication cost and easy-to-use low-cost compared to the PSTN is a mobile phone of a conventional, and use of the Internet phone is spreading. Construction as part of the broadband convergence network(BCN), Internet service provider(KT, SKT, LG) has converted to Internet phone telephone network to all government agencies. In addition, members of the public also have an Internet phone service that you are using. In this paper, we analyze the hacking attack on IP-PBX in the IETF SIP-based that are used in Internet telephony, to the study. The test bed is constructed in the same way as the Internet telephone system to perform studies carried hacking attacks on IP-PBX, analyze the results and to extract evidence forensics. When used in crime by hacking the Internet telephone, we propose a method which can be used as evidence in forensic having legal effect.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.12 no.1
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• pp.60-70
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• 1987

Recently the tendency of the network system development rapidly progresses toward ISDN that intergrates all presetn-day communication networks and services into a single, universal network set up on the basis of the exisiting telephone network. For this reason many countries pay worldwide attention to the researches about ISDN, especially to the researches about the exchange and the ISDN user-network interface which is one of the most important parts of network system. This paper is the first part of the two-par papers describing the ISDN user-network interface. in this paper, after surveying the architecture of ISDN exchange recommended by CCITT, the general architecture of the ISDN exchage is proposed, Based on this architecture, the switching emulator is implemented, and the necessary conditions of the ISDN exchage(LAPO, CCP etc) are also studied.

• Journal of Digital Convergence
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• v.12 no.8
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• pp.235-242
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• 2014

Internet telephony is an Internet service which supports voice telephone using VoIP technology on the IP-based Internet. It has some advantages in that voice telephone services can be accompanied with multimedia services such as video communication and messaging services. In this paper we suggested an Asterisk-based Internet telephony system which can be easily scalable. Most current systems use text files to manage their configuration: SIP users, dialplans, IVR service and etc. But we designed the management system which introduces database tables for efficiency and scalability. It also supports web-based functions developed by using Asterisk, Apache, MySQL, jQuery, PHP and open source softwares.