• Broadcasting and Media Magazine
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• v.19 no.1
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• pp.48-55
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• 2014

One of the recent noticeable evolutions in mobile communication systems is that wideband-codec is deployed rapidly in VoLTE (Voice over Long Term Evolution) service or HD voice. This paper is concerned with next generation HD voice or VoLTE service that is coined to describe high quality communication with super-wideband voice codec. 3GPP EVS (Enhanced Voice Service) Codec is being standardized to develop the super-wideband voice codec. This paper deals with the codec design constraints, performance requirements, the status of standardization, and finally perspective on VoLTE service in future.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.208-211
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• 2002

At present there is no hardware design system by using the voice. We try to use the voice communication to the hardware design and to communication with the computer. This time, we make au application that introduces voice communication and we execute small-scale circuit description.

• Journal of information and communication convergence engineering
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• v.1 no.4
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• pp.205-208
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• 2003

Voice activity detection is a important problem in the speech recognition and speech communication. This paper introduces new feature parameter which are reconstructed by spectral entropy of information theory for robust voice activity detection in the noise environment, then analyzes and compares it with energy method of voice activity detection and performance. In experiments, we confirmed that spectral entropy and its reconstructed parameter are superior than the energy method for robust voice activity detection in the various noise environment.

• International Journal of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.59-63
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• 2019

VoIP technology is a technology for exchanging voice or video data through IP network. Various protocols are used for this technique, in particular, RTP(Real-time Transport Protocol) protocol is used to exchange voice data. In recent years, with the development of communication technology, there has been an increasing tendency of services such as "Kakao Voice Talk" to exchange voice and video data through IP network. Most of these services provide a service with security guarantee by a user authentication process and an encryption process. However, RTP protocol does not require encryption when transmitting data. Therefore, there is an exposition risk in the voice data using RTP protocol. We will present the risk of the situation where packets are sniffed in VoIP(Voice over IP) communication using RTP protocol. To this end, we configured a VoIP telephone network, applied our own sniffing tool, and analyzed the sniffed packets to show the risk that users' data could be exposed unprotected.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.6
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• pp.29-35
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• 2013

The heterogeneous emergency communication radios is used at disaster management agencies of Korea to response activity in the event of disaster. The compensation method by communication connection time difference is necessary to seamless voice communication because radios have different communication method and delay. In this paper, we suggested solution for voice transmission chance and data loss problem.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.229-232
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• 2000

AAL2 has been adopted for bandwidth-efficient trans-mission of low bit tate traffic over ATM networks in ITUT and ATM Forum. Since ATM/AAL2 is expected to be used as a switching technology in third-generation mobile access networks and mobile data traffic is expected to increase rapidly in near future, there must be a need for efficient scheduling scheme satisfying the QoS requirement of ow bit rate voice as well as the one of high bit rate data. In this paper, we propose a new class-scheduling scheme to improve data packet loss probability, while Qos of voice traffic is guaranteed, when data traffic is multiplexed together with mobile voice traffic into a single ATM VCC. The proposed scheme can efficiently support data traffic by assigning a time threshold value to voice traffic. Through simulation study, we show that the proposed scheme does not only achieve better efficiency for providing both mobile voice and data services than HOL class-scheduling scheme and normal FIFO scheme, but also guarantees mean voice packet delay under a certain criteria.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.471-475
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• 2000

Voice and data are transmitted over a single packetized data communications network which is designed for data communications. The public switched telephone network for voice and the packet data network for data are merging into a single data network to get efficiency and to reduce operational cost. However, integrating voice and data transmission over a single data network is not easy because voice should be transmitted without delay but data should be transmitted without error. Advances in technology begin to overcome basic differences. Several integration methods in voice and data will be examined and reviewed here. Moreover, trends and problems on integration will be also discussed.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1962-1967
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• 2008

A event recorder system stores a train speed and the related information for train operation in real time. Using those information, we can analysis the train operation and the reason of train accident. Currently the event recorder only manipulate the data related the train operation mechanically and electrically. In this paper we propose the event recorder to record the voice communication between the manager in the control center and train operator. By recording the voice communication in the high speed train, the correctness of analysis of train accident can be increased. The system architecture of the event recorder with voice recording is studied and interface between other equipment is proposed. And the software architecture of new event recorder is developed. We study the method of converting analog voice signal into digital data and compressing method. Also the architecture of memory to store the compressed voice data and regeneration of original analog voice are studied.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.3
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• pp.319-325
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• 2015

Remarkable advances in wireless communication technology have enabled communications among people who are far away from each other. In recent, the needs of local area voice communication using a wireless system based on low-cost and simple hardware are rapidly rising. However, since these applications require that the multi-users communicate on the same wireless channel in a small area, the existing voice technologies are not suitable for directly applying to these applications. Therefore, in this paper I propose a novel idea enabling multi-user voice communication. In particular, as a short range wireless solution, I employ the IEEE 802.15.4 based on low power and low cost. However, since originally the standard is not developed for voice communication, we extend the original scheme to be suitable for the voice communication by utilizing the extended concept of GTS. The capacity and validity of the proposed scheme are evaluated through quantitative analysis in various voice compression rates.

• Proceedings of the IEEK Conference
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• summer
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• pp.387-390
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• 2004

In this paper, we design and implement practical application service using VoiceXML. And we suggest new solutions of problems can be occurred when implementing a new systems using VoiceXML, based on the fact. Up to now, speech related services were developed using API (Application Program Interface) and programming languages, which methods depend on system architectures. It thus appears that reuse of contents and resource was very difficult. To solve these problems, nowadays, companies develop their applications using VoiceXML. Advantages of using VoiceXML when developing services are as follows. First, we can use web developing technologies and technologies for transmitting web contents. And, we can save labors for low level programming like C language or Assembler language. And we can save labors for managing resources, too. As the result of these advantages, we can reduce developing hours of applications services and we can solve problem of compatibility between systems. But, there's poor grip of actual problems can be occurred when implementing their own services using VoiceXML. To overcome these problems, we implemented interactive stock trading system using VoiceXML and concentrated our effort to find out problems when using VoiceXML. And then, we proposed solutions to these problems and analyzed strong points and weak points of suggested system.