• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.4
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• pp.53-58
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• 2008

This paper designs sigma-delta D/A Converter with a high resolution and low power consumption. It reorganizes the input data along LJ, RJ, I2S mode and bit mode to the output data of A/D converter. The D/A converter decodes the original analog signal through HBF, Hold and 5th CIFB(Cascaded Integrators with distributed Feedback as well as distributed input coupling) sigma-delta modulation blocks. It uses repeatedly the addition operation in instead of the multiply operation for the chip area and the performance. Also, the half band filters of similar architecture composed the one block and it used the sample-hold block instead of the sinc filter. We supposed simple D/A Converter decreased in area. The filters of the block analyzed using the matlab tool. The top block designed using the top-down method by verilog language. The designed block is fabricated using Samsung 0.35um CMOS standard cell library. The chip area is 1500*1500um.

• The Journal of Korean Association of Computer Education
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• v.10 no.1
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• pp.77-88
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• 2007

More flexible learning models are needed, and learning environments that operate through mobile technologies such as portable multimedia players(PMP) provide useful tools in implementing these learning models. The main attractant of PMP is often their versatility: being able to load and play different formats of video, audio, digital images, and interactive media. In this paper, we investigate the factors influencing the usage and acceptance of the PMP for study, based on the extended version of the Technology Acceptance Model (TAM). Based on data collected from online survey, we show that perceived usefulness, perceived ease of use, flow and perceived enjoyment are the major determinants for users to play PMP for study purpose. Factors, including ease of use, contents-credibility are shown to determine the level of perceived usefulness; additionally, perceived usefulness, ease of use and perceived enjoyment are shown to directly affect the level of flow. Based upon the statistical results, some useful guidelines for developing learning contents are also provided.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.1
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• pp.197-204
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• 2010

This paper proposes a new body-effect compensated switch configuration for low voltage and low distortion switched-capacitor (SC) applications. The proposed circuit allows rail-to-rail switching operation for low voltage SC circuits and has better total harmonic distortion than the conventional bootstrapped circuit by 19 dB. A 2-1 cascaded sigma-delta modulator is provided for performing the high-resolution analog-to-digital conversion on audio codec in a communication transceiver. An experimental prototype for a single-stage folded-cascode operational amplifier (opamp) and a 2-1 cascaded sigma-delta modulator has been implemented m a 0.25 micron double-poly, triple-metal standard CMOS process with 2.7 V of supply voltage. The 1% settling time of the opamp is measured to be 560 ns with load capacitance of 16 pF. The experimental testing of the sigma-delta modulator with bit-stream inspection and analog spectrum analyzing plot is performed. The die size is $1.9{\times}1.5\;mm$.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.16 no.1
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• pp.10-14
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• 2005

Background and Objectives : Vowels are characterized on the basis of formant patterns. The first formant(F1) is determined by high-low placement of the tongue, and the second formant (F2) by front-back placement of the tongue. The fundamental frequency(F0) of a soprano often exceed the normal frequency of the first formant. And the vocal intensity is boosted when F0 is high and a harmonic coincides with a formant. This is called a formant tuning. Experienced singers thus learned how to tune their formants over a resonable range by lowering the tongue to maximize their vocal intensity. So, the current study aimed to identify the formant tuning in one experienced soprano by comparing the first formants of vowel [i] in three different voice production : speech, ascending scale, and vocalize. Materials and Method : All voices recordings of vowel [i] in speech, ascending scale (from F4 note to A4 note), and vocalize(:Ridente la calam") were made with digital audio tape-corder in a sound treated room. And the captured data were analyzed by the long term average(LTA) power spectrum using the FFT algorithm of the Computerized Speech Lab(CSL, Kay elementrics, Model, 4300B). Results : Although the first formant of vowel [i] in speech was 238Hz, those of ascending scale [i] were 377Hz, 405Hz, 453Hz respectively in F4(349z), G4(392Hz), A4(440Hz) note, and 722Hz, 820Hz, 918Hz respectively in F5 (698Hz), G5(784Hz), A5(880Hz) note. In vocalize, first formants of [i] were 380Hz, 398Hz, 453Hz respectively in F4, G4, A4 note, and 720Hz, 821Hz, 890Hz respectively in F5, G5, A5 note. Conclusion : These results showed that the first formant of ascending scale and vocalize sustained higher frequency than fundamental frequency in high pitch. This finding implicates that the formant tuning of vowel [i] in ascending scale was also noted in vocalize.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.837-840
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• 2003

Recently the multimedia streaming traffic such as digital audio and video in the Internet has increased tremendously. Unlike TCP, the UDP protocol, which has been used to transmit streaming traffic through the Internet, does not apply any congestion control mechanism to regulate the data flow through the shared network. If this trend is let go unchecked, these traffic will effect the performance of TCP, which is used to transport data traffic, and may lead to congestion collapse of the Internet. To avoid any adverse effort on the current Internet functionality, A study on a new protocol of modification or addition of some functionality to existing transport protocol for transmitting streaming traffic in the Internet is needed. TCP-frienly congestion control mechanism is classified with window-based congestion control scheme and rate-based congestion control scheme. In this paper, we propose an algorithm for improving the transmitting rate on a hybrid TCP-friendly congestion control scheme combined with widow-based and rate-based congestion control for multimedia streaming in the internet.

• The Transactions of the Korea Information Processing Society
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• v.6 no.8
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• pp.2171-2178
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• 1999

In these days, as rapid growth of multimedia industries and development of techniques, and effort to develop DAVIC(Digital Audio-Visual Council) systems which support multimedia services such as VOD(Video onn Demand) and teleshopping is being done. Therefore it will be indispendable to establish a new conformance testing method related DAVIC system with respect to their standard specification. DSM-CC is a core part of DAVIC and adopts DSM-CC U-N for S3 information stream which plays a part in connection establishment and release of session and transmission layer, and DSM-CC U-U for S2 which operates user application of the system. In this paper, we propose a new conformance testing architecture and methodology based on scenario in order to test DSM-CC U-U which doesn't have any message sequences.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.437-440
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• 2007

Recently embedded system developed a lot. Physically, embedded systems range from portable devices such as digital watches and MP3 players, to large stationary installations like traffic lights, factory controllers, or the systems controlling nuclear power plants. This paper focuses on implementation of portable device which is applicable to the child-kidnap or missing child prevention system in residential area or public area. To be specific, this device is to transmit video data which comes from the camera in the device into the host PC via WLAN. Embedded hardware platform consists of s3c2440 with ARM9 core, WindowsCE OS and other sensors. OS enables the platform to do multitasking jobs which are handling GPS data, taking video, capturing audio via microphone in the device and transfer all kind of realtime data to the host PC.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.5
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• pp.602-609
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• 2016

In a smart society, politicians analyze the big data of voters to build a favorable political positions. In other words, a variety of digital footprints uploaded in SNS or Internet are used to set the election strategies and political directions. In comparison, it is difficult for voters to extract intention information about how politicians are performing a political acts. Therefore, it is important that voters need to analyze what intention of politicians are like for two way interaction between voters and politicians. For this, in this paper, we want to do the identification by analyzing IT technologies to narrative styles of politicians who pursue relative advantages or gains compared to other competitors. The experiments will be carried out to identify about what relative advantages compared to other competitors by narrative styles of next presidential candidates who are expected to run into the next presidential election by analyzing the usual audio interviews.

• Journal of Broadcast Engineering
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• v.12 no.3
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• pp.203-213
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• 2007

DMB video/audio service was successfully launched. DMB data service is a matter of primary concern now. The TTI(Traffic and Travel Information) service is considered as a killer application of the data service. Tn this paper, we propose a method for design and implementation of the broadcasting system for TTI service. The proposed TTI service system consists of an authoring tool, the DB module, the Transmission module and Monitoring module. This system satisfies the national TTA standards of the Traffic and Travel Information data services for terrestrial DMB; TPEG(Transport Protocol Experts Group) platform. The system was designed to support real-time automatic transmission for CTT and CTT SUM, and non real-time authoring & automatic transmission for POI and SDI, and was focused on the capability to make high-quality contents efficiently and to send them to the data inserter reliably. The performance of the implemented system was proven through the conformance tests with the various commercial receivers. After the continuous upgrade, the system is being used in commercial service.

• Science of Emotion and Sensibility
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• v.8 no.3
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• pp.231-240
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• 2005

The social participation and economic position of the woman come to be high, they are rising to the market as a core consumer and trend inventor leading the fashion. So that, we have to recognize the woman with one axis of product development, it is necessary to the product development and the strategy which it will put woman oriented sensibility in product design. From this research, it reviews the backgrounds from social culture and the economic marketing sides through the digital product recently, it analyzed the features of woman characteristic designs which is embossed the product. Also it connected actual product development, it developed a woman oriented sensibility audio which reflected a woman's consuming trend, life style and the preference product style. It proposed the necessity of woman oriented product development ultimately and researched the product design strategy for the reflection of woman sensibility.