• Proceedings of the IEEK Conference
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• 2000.06d
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• pp.98-101
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• 2000

On CELP type Vocoders G.723.1 6.3kbps/5.3kbps Dual Rate Speech Codec, which is developed for Internet Phone and videoconferencing, uses VAD(Voice Activity Detection)/CNG (Comfort Noise Generator) in order to reduce the bit rate in a silence period. In order to reduce the bit rate effectively in this paper, we first set the boundary condition of the energy threshold to prevent the consumption of unnecessary processing time, and use three decision rules to detect an active frame by energy, pitch gain and LSP distance. To evaluate the performance of the proposed algorithm we use silence-inserted speech data with 0, 5, 10, 20dB of SNR. As a result when SNR is over 5dB, the bit rate is reduced up to about 40% without speech degradation and the processing time is additionally decreased.

• Journal of Korea Multimedia Society
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• v.13 no.8
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• pp.1194-1201
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• 2010

Currently embedded system has been widespreadly used in digital Set-top box, mobile phone, USN, etc and the significance of security has been increased due to be necessarily embedded in these all system. In this paper we propose new integrity verification scheme among the main security requirements in target system based on the korea TTA standard, security reference model for embedded operating system, published in december 2006. Moreover the proposed scheme is more effective than the previous scheme, Jung, et al.[2,6].

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1563-1567
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• 2005

The Home network system means that information appliances, Home PCs, etc., using wired or wireless network method enable to control and share with peripheral devices such as internet, shared data, a scanner and a printer, and it is networking solution, which intelligent communication will be possible as the system which can do a remote control such as TV Set, refrigerators, air conditioners, DVD players, digital camcorders based on external network using an internet, a potable information terminal and a mobile phone whenever, wherever and freely. In this study, the home network interface solution is used one of the wired network standards, PLC (Power-Line Communication) technology, so we can construct of intelligent home network's home controller without re-build a network at home. On keeping with current waves of thought, we will focus on a home controller development with great interest which is enabled to do an effective managed control, applying intelligent home network technology which can be new paradigm like a cyber apartment.

• Transactions of Materials Processing
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• v.14 no.3 s.75
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• pp.200-206
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• 2005

In general, a lot of small electrode is needed for making precision injection molds, such as cell phone mold and precision connector mold, because of the limitations of NC milling process. Those small electrodes usually have very simple shapes and the actual cutting time is so short, but many NC programs and set-up process, a very complicated and time consuming Job, are needed for each electrode. This paper deals the method for increasing the productivity of machining electrodes. In this work, the process standardization of machining electrode was done and special jig fer machining small electrodes was developed. Automatic tool path optimization software was also developed to minimize tool changing time. In addition, in-line cutting tool measuring system was adopted. The productivity of machining for small electrode has been increased up to $100\%$.

• STI Policy Review
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• v.7 no.2
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• pp.35-59
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• 2016

The strategic importance of innovation ecosystems has received increased attention from both the academic and policy perspectives. However, there is only limited empirical evidence on the importance of these ecosystems from the perspective of younger firms. This study focuses on the role of ecosystems for young innovative companies (YICs) and is based on a unique set of phone survey data from Finland and South Korea. The results are threefold: (1) Finnish YICs participate more actively in ecosystems than Korean YICs; (2) on average, Korean YICs report to have experienced lower ecosystem impact compared to Finnish YICs; (3) in both countries, key organizations of the ecosystems are represented on the board of directors in about one-third of the sample firms.

• The Journal of Information Systems
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• v.15 no.4
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• pp.189-209
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• 2006

The progress of mobile internet technologies has changed user access to information. The mobile internet allows to obtain contents and services from wireless networks via mobile devices. The purpose of this study is th find out important factors that influence on the customer purchase intention by mobile internet environment. Base on TAM(Technology Acceptance Model) and the latest literature, a comprehensive set of constructs and hypotheses were compiled with a methodology for testing them. We suggested five factors that effect purchase intention in mobile internet environment: Enjoyment Ease of use, Usefulness, Mobility, Trust To validate the research model, we collected data from cellular phone user using an online survey. The results of this study are as follows. First enjoyment ease of un, usefulness, and mobility had positive effects on trust. Second, Usefulness, ease of use, and trust had positive effects on purchase intention to use mobile internet. Third, enjoyment and mobility did not have positive effects on purchase intention to use mobile internet. Based on these results, we suggest marketing strategies.

• The Journal of Information Systems
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• v.15 no.4
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• pp.149-170
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• 2006

This research investigates the determinants of the customer's acceptance intuition for the ads on cellular phone. For this purpose, this research set up a model with such variables as entertainment information irritation, credibility, flow experience, attitudes and acceptance intention based on TAM and Flow theory. For the more reasonable and generalizable results, this study targets two different customer groups in Korea and Japan and compare the responses from these two groups using AMOS, the structural equation modeling and a second-generation multi - variant techniques.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.187-194
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• 2021

This paper presents a margin-based face liveness detection method with behavioral confirmation to prevent spoofing attacks using deep learning techniques. The proposed method provides a possibility to prevent biometric person authentication systems from replay and printed spoofing attacks. For this work, a set of real face images and fake face images was collected and a face liveness detection model is trained on the constructed dataset. Traditional face liveness detection methods exploit the face image covering only the face regions of the human head image. However, outside of this region of interest (ROI) might include useful features such as phone edges and fingers. The proposed face liveness detection method was experimentally tested on the author's own dataset. Collected databases are trained and experimental results show that the trained model distinguishes real face images and fake images correctly.

• Proceedings of the KSPS conference
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• 1996.10a
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• pp.456-463
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• 1996

In this paper, we discussed three cases to see the effects of the characteristics of Hangul writing system. In applications such as computer Hangul shorthands for ordinary people and pushbuttons with Hangul characters engraved, we found that there is much advantage in using Hangul. In case of Hangul Transliteration, we discussed some problems which are related with the characteristics of Hangul writing system. Shorthands use 3-set keyboards in England, America, and Korea. We saw how ordinary people can do computer Hangul shorthands, whereas only experts can do computer shorthands in other countries. Specifically, the facts that 1) Hangul characters are grouped into syllables (syllabic blocks) and that 2) there is already a 3-set Hangul keyboard for ordinary people allow ordinary people to do computer Hangul shorthands without taking special training as with English shorthands. This study was done by the author under the codename of 'Sejong 89'. In contrast like QWERTY or DVORAK, a 2-set Hangul keyboard cannot be used for shorthands. In case of English pushbuttons, one digit is associated with only one character. However, by engraving only syllable-initial characters on the phone pushbuttons, we can associate one Hangul "syllable" with one digit. Therefore, for a given number of digits, we can associate longer words or more meaningful words in Hangul than in English. We discussed the problems of the Hangul Transliteration system proposed by South Korea and suggested their solutions, if available. 1) We are incorrectly using the framework of transcription for transliteration. To solve the problem, the author suggests that a) we include all complex characters in the transliteration table, and that b) we specify syllable-initial and -final characters separately in the table. 2) The proposed system cannot represent independent characters and incomplete syllables. 3) The proposed system cannot distinguish between syllable-initial and -final characters.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.122-135
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• 2011

Mobile spam message is a harmful factor which makes receivers to be annoyed and leads to unnecessary social cost. Unwanted junk messages flowing to a smart phone ruin main purpose of the smart work system to enhance the productivity, so we need to study on this area. In this paper, we proposed a novel spam filter on the smartphone in order to reduce computing process and improve the accuracy rate by feedback of error results to a training sample set. As the spam classifier operates on the smartphone independently with training on only user's received data, it could reflect user preference. The authorized personal computer takes on heavy works, such as preprocessing, feature selecting and training process, and the smartphone takes on light works to block junk messages. Experimental results showed reasonable accuracy rate of over 95%, and we found that the application occupied constant computing resources while running on the phone.