• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.134-144
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• 2009

The Ubiquitous/Unified Communication Platform supports various multimedia communication tools such as VoIP, Email, Unified Messaging, Instant Messaging, Web Conferencing, Audio/Video Communication etc. In this paper we introduced the main functions and architecture of the Unified Communication Platform and we researched on the function analysis and design of the VoIP System that supports PC-to-PBX/PSTN Phone and PBX/PSTN Phone-to-PC communications through the connectivity and interoperation with PSTN.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.67-69
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• 2003

현재 인터넷은 음성을 포함한 실시간 정보의 제공을 기반으로 정보에 대한 욕구를 충족시키고 있으며, 이러한 인터넷의 실시간을 바탕으로 사용자는 새로운 서비스에 대한 요구를 창출하게 되었고, 저렴한 인터넷을 이용하여 Public Switched Telephone Network(PSTN)과 같은 기존 통신망을 대체하는 연구가 활발히 이루어지고 있다. VoIP(Voice over Internet Protocol)는 이러한 요구에 부흥하는 인터넷의 대표적인 서비스로 등장하고 있으며, MGCP, SIP 그리고 H.323 같은 프로토콜을 기반으로 VoIP 서비스를 위한 다각적인 접근과 연구가 진행 중이다. 본 연구는 VoIP 서비스를 위한 여러 프로토콜 중 IETF가 주관하고 있는 MGCP(Media Gateway Control Protocol) 스팩에 따라 MGCP를 구현하였으며, 댁내 서비스를 위한 인터넷에서의 VoIP 신뢰성을 보장하는 방안으로 기존 PSTN망을 백업형태로 지원하는 방안을 연구하여 특정 번호는 Call Agent(CA)와 MGCP 프로토콜로 통신하지 않고 임의 변경 없이 자동으로 기존 망으로의 발신이 가능한 시스템을 설계하고 구현하였다.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.47-47
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• 2000

Most measuring devices are equipped with RS-232 or GPIB interface for communicating data with computers. If the measuring devices can be accessed by a server computer, the valuable information from the devices can be effectively shared with other computers via internet. But, if the measuring devices and the server computer are too far away, it is difficulty to directly connect them by RS232 interface. PSTN(Public Switched Telephone Network) refers to the world's collection of interconnected voice-oriented public telephone networks. Measuring computer system which is equipped with RS232 interface and modem for PSTN can be introduced to overcome the aforementioned distance problem, In this work, an internet based remote monitoring system which utilizes PSTN and VRML for 3-dimensional GUI is proposed.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.157-160
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• 1988

This paper describes the development of the Interfacing unit between PSTN and interphone network. The designed and realised system detects the ring signal from PSTN and makes off-hook condition when it is detected. Then the caller can hear the response tone from the unit and the tones of the interphone network condition. The developed system receives the interphone number to which the caller wants to connect by MFC tones and drives Interphone switch matrix. Thus, a call is connected to the interphone user directly. The caller may press the interphone number up to 10 digits and the last two of which are recognized as valid ones. The caller must press the first digit within 20 seconds after system response.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1988.10a
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• pp.44-47
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• 1988

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2313-2318
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• 2012

With the widely applications of tactical radio networks, end-to-end secure speech communication in the heterogeneous network has become a very significant security issue. High-grade end-to-end speech security can be achieved using encryption algorithms at user ends. However, the use of encryption techniques results in a problem that encrypted speech data cannot be directly transmitted over heterogeneous tactical networks. That is, the decryption and re-encryption process must be fulfilled at the gateway between two different networks. In this paper, in order to solve this problem and to achieve optimal end-to-end speech security for heterogeneous tactical environments, we propose a novel mechanism for end-to-end secure speech transmission over ultra high frequency (UHF) and public switched telephone network (PSTN) and evaluate against the performance of conventional mechanism. Our proposed mechanism has advantages of no decryption and re-encryption at the gateway, no processing delay at the gateway, and good inter-operability over UHF and PSTN.

• Korean Journal of Remote Sensing
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• v.18 no.6
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• pp.345-358
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• 2002

DGPS(Differential Global Positioning System) and RTK(Real time Kinematic) are in one of today's most widely used surveying techniques. However surveying with these techniques is restricted by the distance between reference and rover station, and it is difficult to process data in realtime by their own organizational limitation in precise measurement of positioning. To meet these new demands, in this paper, new DGPS and RTK correction data services through the Internet and PSTN(Public Switched Telephony Network) have been proposed. For this purpose, a DGPS and RTK error correction data transmission system is implemented for long-distance using the Internet and PSTN which allows a mobile user at which the rover receiver is located to receive the correction data from the reference in realtime, and analyzed and compared with DGPS and RTK performances by experiments through the Internet and PSTN for the distance and the time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.293-300
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• 2007

As the development of the various IP-based services, it is expected that Internet telephony service will gradually replace the traditional PSTN-based telephony service. But there are many issues resolved to spread the Internet telephony service. One of them is to support the emergency services in the Internet telephony. In the case of USA, it has been regulated that 911 services should be supported in the Internet telephony services using VoIP on the similar performance level to PSTN 911 service. According to the regulation, basic VoIP 911 calls should be routed to the general access line of LEA without the location information or the callback number, but the enhanced VoIP 911 calls with the location information and callback number should be routed on the dedicated 911 network and destined to the local 911 distribution center such as PSAP. But, in the current VoIP-based Internet telephony network, the emergency call service has not been handled as one of the special services as well at has a worse performance in comparison to it on PSTN. Moreover, the service has a critical problem that it can not be destined to the nearest PSAP because of the insufficient information about the location information and the call back number. In this paper, we suggest the SIP-based emergency call service mechanism in order to resolve the problems above mentioned. This suggested mechanism is implemented to show its effectiveness and efficiency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.529-532
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• 2012

Building the super broadband network is the key competence for fostering the economy. Over the super broadband network voice services have changed rapidly to be served to VoIP rather than PSTN most incumbents have used. This results in reforming the interconnection regulations. From network structures, technologies, and POI to costing methods there are many concerns to discuss between stakeholder. This paper reviewed the IP-LRIC model over NGN designed by national regulatory angencies (Austria, Belgium, Denmark, France, Germany, Netherlands, Norway, Sweden). We draw implications for developing IP-LRIC models from other IP-LRIC model studies.

• The KIPS Transactions:PartA
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• v.11A no.6
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• pp.433-438
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• 2004

In this paper, we describes the development of Bluetooth network Access Point(AP) for the access network connection of Bluetooth devices at home. Unlike headset, mouse, and keyboard, the AP should have capability to support multiple connection and stabilized network throughput. Our AP allows various kinds of Bluetooth terminals to access the access network like xDSL and PSTN(Public Swithced Telephone Network) stably. Especially, users can access the PSTN at home instead of expensive CDMA network through the AP by using the one-phone which is the cellular phone with the Bluetooth module.