• Proceedings of the KSPS conference
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• 2003.10a
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• pp.149-152
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• 2003

In this paper, data-driven temporal filter methods[1] are investigated for robust feature extraction. A principal component analysis technique is applied to the time trajectories of feature sequences of training speech data to get appropriate temporal filters. We did recognition experiments on the Korean connected digit telephone speech database released by SITEC, with data-driven temporal filters. Experimental results are discussed with our findings.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.5-8
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• 1999

In this paper, we suggest a way of implementing ISDN S-Interface through two-wire premises telephone networks instead of using four wires as in the existing ISDN systems. This will help many developing or underdeveloped countries in the world to introduce ISDN services, where they have only two or low wires as in-building telephone networks. We suggest new physical-layer specifications for two-wire S-interface similar to that in ITU-T recommendations I.430 for four-wire systems, design a tranceiver according to the suggested specifications, and implement it using an FPGA We build a test board with the chip on it and succeed in connecting to Internet.

• Journal of Korean Society for Quality Management
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• v.22 no.2
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• pp.79-88
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• 1994

Delay has influenced customer satisfaction while using a telephone. It has been ranked second after transmission impairments in annoyance to customers. Therefore, it is important to analyze its behavior not only to increase the quality of service for the customers, but to provide its information to network planners and administrators and to designers of equipment and systems. In this paper, we consider a log-normal model as a candidate for describing the statistical behavior of the post dialling delay, i.e., the time to connect a call to the telephone network after dialling. Based on the real data, the log-normalness of the post dialling delays are convinced for the long distance calls, but not supported for the local calls. Uses of graphical plotting paper and statistical test of fit art discussed.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04b
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• pp.1197-1200
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• 2001

VXML은 사람 목소리나 전화기의 톤과 같은 음향 입력과 컴퓨터에 의해 합성 또는 녹음된 목소리를 들려주는 음성 출력을 가지는 음성 브라우저를 위한 웹 저작 언어이다. 본 논문에서는 VXML을 이용하여 작은 규모의 회사나 SOHO 사업자들에게 최적화된 ARS 기능, 음성 인식 기술을 이용하여 음성 메시지 저장 및 지능적 검색 기능, 사용자 부재 시 착신 전환 또는 SMS 통보를 찰 수 있는 개인용 전화 도우미 (PTA; Personal Telephone Assistant)의 설계 및 구현에 관하여 기술한다. PTA는 VXML 인터프리터를 내장하고 동적으로 VXML 문서를 적재함으로써 고객맞춤형의 ARS 기능을 지원한다는 장점을 갖는다.

• Korean Management Science Review
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• v.26 no.3
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• pp.11-21
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• 2009

In this paper, we proposed some valuable analysis results of cultivation campaign marketing in A mobile telephone company. The cultivation campaign marketing is a new outbound TM campaign strategy composed of 4 steps for new subscribers. During the analyses, attrition rate of A mobile company, outbound TM rejection rate, contact rate/call success rate and additional service attrition rate after subscription are measured as an effect of cultivation campaign. The results showed that there were no statistical significance in improving retention rate between customers experienced 4 step cultivation campaign and control group. However, the cultivation campaign had a better effect on improving response rate and success of selling additional service product of mobile company compared to general selling campaign. This is because cultivation campaign group had been taking care of from subscription time. It is suggested that cultivation campaign had better confined customers more likely to buy additional service to outbound TM for the sake of financial efficiency.

• International Journal of Quality Innovation
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• v.2 no.1
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• pp.117-128
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• 2001

It is widely recognized that ISO 9000 certification bring some profits, such as enhancement of quality system and some concerns. Since one of the major concerns is cost for certification, this paper considers the cost for ISO 9000 certification in Japanese companies through review some winning reports and case studies. Specifically, a model that describes the certification activities and their cost is derived through reviewing some winning reports in order to give a framework of cost estimation. Based on the model, we estimate the certification cost in an electric division of a company through an interview survey. Furthermore, we focused on the cost for promotion and administration as a cost for the sake only certification, because these activities will not be needed if a company does not implement ISO certification. It is concluded that this cost may vary approximately 300,000-700,000 (US$) per certification by the interview and telephone surveys to Japanese steel companies.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.2
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• pp.50-58
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• 1983

In this paper, a field trial of the Korean-made optical fiber communication system is described. This system was installed between Gu-Ro and Ann-Yang telephone offices on November 1981, and carries a 44.7Mb/s NRZ signal(672 voice channel equivalent). For this trial, optical fiber cable, optical terminal equipment, optical repeater, fusion splicer and measurement equipment have been developed. Employing graded index optical fiber at a wave length of $0.85\;\mu\textrm{m}$, average optical attenuation and splicing losses of 3.6 dB/km and 0.4 dB, resectively, were realized. With link margins of 8~20dB and bit error rate of less than $10^{-10}$, this system has been carrying live traffic between Seoul and Ann Yang telephone offices.

• Speech Sciences
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• v.8 no.1
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• pp.159-165
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• 2001

In this paper, we make an experiment on speech recognition systems with barging-in and non-barging-in utterances. Barging-in capability, with which we can say voice commands while voice announcement is coming out, is one of the important elements for practical speech recognition systems. Barging-in capability can be realized by echo cancellation techniques based on the LMS (least-mean-square) algorithm. We use three kinds of telephone interface boards with barging-in capability, which are respectively made by Dialogic Company, Natural MicroSystems Company and Korea Telecom. Speech database was made using these three kinds of boards. We make a comparative recognition experiment with this speech database.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.801-804
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• 2013

Automatic dialing function of the telephone is to support communication such as emergency call, public relations and guidance service by automatic dialling of individual phone number. In this paper, we analyze the relevant provisions of each country and discuss the direction of institutional maintenance related to automatic dialling function.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1819-1822
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• 2002

The authors propose a robust symbol timing recovery (STR) for telephone line modems supporting data rates up to 32 Mbps. The STR is initialized by a start signal from carrier sensor, and the novel method is proposed which resolves the difference between the frequency of the transmitter's clock and the receiver's clock, called baud frequency offset. The proposed method is applied on digital receiver in a 16 frequency diverse quadrature amplitude modulation (FDQAM) system.