• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1496-1502
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• 1998

In this paper, a real-time audio broadcasting service system which is robust to loaded traffic on the Internet is developed. For implementing reliable real-time data transfer, the transfer characteristics of TCP/IP and UDP/IP was compared and analyzed. For lost packet recovery, redundant audio data algorithm was used and interleaving technique was applied for scattering consecutive packet loss. Test results showed, when using TCP/IP, pause occurred during playback, and when using UDP/IP, a stable receive rate was noticeable but the quality of the sound was lower than that of uisng TCP/IP. The recovery rate using redundant audio data and interleaving technique is shown in Fig. 9 and the delay is shown in Fig 4.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.8
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• pp.468-476
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• 2000

Nowadays, ozone is mainly utilized for water treatment and home equipments. Although the demand for ozone is increasing, the ozone yield of silent discharge type ozonizer is low. Therefore, it is expected to improve the energy efficiency and ozone yield of an ozonizer. In this paper, a new ozone generation system is proposed. The 60[Hz] three-phase voltage is applied to three-phase superposed discharge type ozonizer(3PSDO) which has three electrodes(central, internal and external electrodes). There is no discharge pause time when three-phase voltage is applied due to 120-degree phase difference of applied voltage. The synergy effect of the three-phase superposed discharge type ozonizer is investigated by comparing with the three sort of single-phase discharge type ozonizer(1PDO). So, three-phase superposed discharge type ozonizer is able to obtain high ozone yield, and optimize discharge space, because this can increase the discharge power at low applied voltage.

• MALSORI
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• no.21_24
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• pp.90-110
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• 1992

The purpose of this thesis is to investigate the intonation features of the last two syllables of rhythmic units, with the exception of the sentence final unit, in the Seoul dialect of Korean. The Model 5500 Sona-graph was used to measure the pitch and duration of the target syllables. There are two classes of materials. One class was designed to determine the intonation of rhythmic units in a natural situation and the other to investigate the intonation of rhythmic units in an artificial situation, in which speakers were asked to read the materials pausing only at the marked boundaries, with a view to identifying the intonation of Seoul dialect more clearly. The findings of this investigation are as follows: (1) Korean averages an 11% rising intonation between the two syllables at the end of a rhythmic unit. (2) The rising rate between the final two syllables' pitch values at the subject rhythmic unit is generally higher than those at other units in a sentence and it seems to be meaningful syntactically. (3) Before a boundary the rhythmic units undergo 'pre-lowering', in which the pitch gradually lowers from the first syllable to the penultimate. (4) Every syllable in each rhythmic unit tends to lengthen when speakers read the materials with a pause between units and the tendency is most salient at the final syllable before a boundary.

• The KIPS Transactions:PartB
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• v.16B no.2
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• pp.141-150
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• 2009

This paper proposes a system that can automatically write singing voices to music notes. First, the system uses Stabilized Diffusion Equation(SIDE) to divide the song to a series of syllabic parts based on pitch detection. By the song segmentation, our method can recognize the sound length of each fragment through clustering based on genetic algorithm. Moreover, this study introduces a concept called 'Relative Interval' so as to recognize interval based on pitch of singer. And it also adopted measure extraction algorithm using pause data to implement the higher precision of song transcription. By the experiments using 16 nursery songs, it is shown that the measure recognition rate is 91.5% and DMOS score reaches 3.82. These findings demonstrate effectiveness of system performance.

• Speech Sciences
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• v.7 no.4
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• pp.235-252
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• 2000

The purpose of this study is to characterize the intonational realizations of vocatives in comparison with those of appositives in English statements and questions, and to compare the realizations produced by English native speakers with those of Korean students. Unlike Pierrehumbert(1980), in which the tag expressions do not have pitch accents, Beckman & Pierrehumbert(1986) proposed that the vocatives have a special status in tonal alignment and duration and that they form an independent phrase with pitch accent. Our results reinforce Beckman & Pierrehumbert(1986): both English native speakers and Korean students realize the vocatives in terms of rising tone, and the appositives in terms of both falling tone in statements and rising tone in questions. Moreover, they pronounced the nouns before vocatives longer than those before appositives. However, native speakers impose the low phrase tone before vocatives in statements and the high tone in questions; whereas, Korean students either put the low phrase tone on pitch contours of both statements and questions, or tend to pause before vocatives, thereby constituting an intonational phrase.

• The Journal of the Acoustical Society of Korea
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• v.34 no.4
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• pp.310-315
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• 2015

A single channel VAD (Voice Activity Detection) algorithm for nonstationary noise environment is proposed in this paper. Threshold values of the feature parameter for VAD decision are updated adaptively based on estimates of means and standard deviations of past non-speech frames. The feature parameter, SPD-TE (Spectral Power Difference-Teager Energy), is obtained by applying the Teager energy to the WPD (Wavelet Packet Decomposition) coefficients. It was reported previously that the SPD-TE is robust to noise as a feature for VAD. Experimental results by using TIMIT speech and NOISEX-92 noise databases show that decision accuracy of the proposed algorithm is comparable to several typical VAD algorithms including standards for SNR values ranging from 10 to -10 dB.

• Journal of Microbiology
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• v.43 no.1
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• pp.11-16
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• 2005

Matrix metalloproteinase (MMP)-9 plays an important role in the pathogenesis of bronchial asthma. Neovastat, having significant antitumor and antimetastatic properties, is classified as a naturally occurring multifunctional antiangiogenic agent. We evaluated the therapeutic effect of Neovastat on airway inflammation in a mouse model of asthma. BALB/c mice were immunized subcutaneously with ovalbumin (OVA) on days 0, 7, 14, and 21 and challenged with inhaled OVA on days 26, 29, and 31. Neovastat was administrated by gavage (5 mg/kg body weight) three times with 12 h intervals, beginning 30 min before OVA inhalation. On day 32, mice were challenged with inhaled methacholine, and enhanced pause (Penh) was measured as an index of airway hyperresponsiveness. The severity of airway inflammation was determined by differential cell count of bronchoalveolar lavage (BAL) fluid. The MMP-9 concentration in BAL fluid samples was measured by ELISA, and MMP-9 activity was measured by zymography. The untreated asthma group showed an increased inflammatory cell count in BAL fluid and Penh value compared with the normal control group. Mice treated with Neovastat had significantly reduced Penh values and inflammatory cell counts in BAL fluid compared with untreated asthmatic mice. Furthermore, mice treated with Neovastat showed significantly reduced MMP-9 concentrations and activity in BAL fluid. These results demonstrate that Neovastat might have new therapeutic potential for airway asthmatic inflammation.

• Korean Journal of Health Education and Promotion
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• v.25 no.4
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• pp.83-92
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• 2008

Objectives: This study was to develop and evaluate a web-based multimedia content for the education of hospice volunteers. Methods: The multimedia content was developed based on Baik's teaching and learning structure plan model. The developed program was evaluated by 24 hospice volunteer university students. Results: On main page, there were 4 menu bars that consisted of a lecture guide, cyber lecture, pause and quiz. In the operation of the web based multimedia content, HTML, Java Script, Photoshop and multimedia technology were utilized. There were significant differences in the test scores, before and after using this web-based learning program. After using a web-based learning program, scores of students were much higher. Conclusion: The developed web based program is based on systematic structure and it can provide hospice volunteers with the educational flexibilities and will be help for them to perform the more efficient hospice care.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.10B
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• pp.876-890
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• 2003

This paper proposes a protocol for the reliableand QoS-aware multicast transport, which is called the Enhanced Communications Transport Protocol (ECTP). The ECTP has so far been developed and standardized in ITU-T SG17 and ISO/IEC JTC 1/SC 6. Differently from the conventional reliable multicast, as shownin the IETF RMT WG, the ECTP additionally provides several distinct features such as tight control of multicast session, tree-based error control, and QoS management. For the tight control of multicast connections, the sender is at the heart of one-to-many group communications, and it is responsible for overall connection management such as connection creation/termination, pause/resumption, and the join and leave operations. for tree-based reliability control, ECTP configures a hierarchical tree during connection creation. Error control is performed within each local group defined by a control tree, which was partly designed like the IETF TRACK approach. Each parent retransmits lost data in response to retransmission requests from its children. For QoS management, ECTP supports QoS negotiation for resource reservation, and it also provides QoS monitoring and maintenance operations. ECTP has been implemented and tested on Linux machine, along with Application Programming Interfaces based on Berkeley sockets. For basic testing of the ECTP functionality, we give some preliminary experimental results for performance comparison of ECTP and TCP unicast transports. In conclusion, we describe the status of ECTP experimentations over APAN/KOREN testbed networks

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2140-2142
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• 2005

This paper presents the experimental results on the preliminary breakdown characteristics under a highly non-uniform electric field in $SF_6/CO_2$ gas mixtures. The impulse preliminary breakdown developments are investigated by the measurements of corona current and light emission images. As a result, the preliminary breakdown development mechanisms for both positive and negative polarities are same. The first streamer corona is initiated at the tip of needle electrode, and the leaders develop with a stepwise propagation and bridge the test gap. The pause time of leader pulses in the positive polarity is significantly shorter than that in the negative polarity. Also, the time interval between the first streamer corona onset and breakdown in the negative polarity was much longer than that in the positive polarity The discharge channel paths in the positive polarity were zigzag. On the other hands, the leader channel in the negative polarity was thicker than that in the positive polarity.