• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2203-2208
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• 2011

This study was to examine the change of vowel acoustic characteristics of the temporomandibular joint disorder patients by maintaining normal vocalization pattern of the temporomandibular joint through increasing the range of motion, that was, the oral cavity sonorant cavity of the temporomandibular joint, related to vowel articulation through temporomandibular training using the physical therapy. The subjects of this study were 3 male adults in 20-30s that were diagnosed with temporomandibular joint disorder. As a result of conducting temporomandibular training program using the physical therapy, the $1^{st}$ Formant Frequency(F1), $2^{nd}$ Formant Frequency(F2), and Fundamental Frequency(F0) of the temporomandibular joint disorder patients were increased compared to before and this showed the change of the $1^{st}$ Formant Frequency(F1) related to the open mouth grade of a vowel, as well as the $2^{nd}$ Formant Frequency(F2), and Fundamental Frequency(F0) related to the front-back of a vowel which shows the relationship between the temporomandibular joint, vowels and voice calculation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.8 s.111
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• pp.725-731
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• 2006

A novel design of frequency multiplier using a feedforward technique and a defected ground structure(DGS) is proposed. The feedforward loop in the proposed frequency multiplier suppresses the fundamental component $(f_0)$, the dumb-bell or spiral shaped DGS diminish unwanted harmonics such as second, third and fourth. Due to the combination of the feedforward structure and the DGS, only the multiplied frequency component$(2f_0,\;3f_0,\;4f_0)$ appears at the output port and the other unwanted components are suppressed excellently. The frequency multiplier is designed at 1 GHz $(f_0)$, by the proposed technique and measured. The measured output power of $2f_0,\;3f_0$ and $4f_0$ is -2.59 dBm, -5.36dBm and -4.57dBm, respectively, when the input power is 0dBm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.11
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• pp.1271-1278
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• 2007

A novel frequency multiplier using composite right/left-handed transmission line is proposed. The left-handed transmission line in the proposed frequency multiplier suppresses the fundamental component($f_0$), while the composite right/left-handed ${\lambda}/4$ open stub diminishes unwanted harmonics. Due to the combination of the left-handed transmission line and composite right/left-handed ${\lambda}/4$ open stub, the only desirable multiplied frequency component such as 3 $f_0$ and 4 $f_0$ are obtained at the output port excellently. For the example of the proposed design, frequency multipliers are designed at 1 GHz of $f_0$ and measured. The measured output power of 3 $f_0$ and 4 $f_0$ is -5.67 dBm and -6.43 dBm, respectively, when the fundamental input power was 0 dBm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.7
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• pp.771-777
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• 2008

In this paper, a frequency doubler using modified time-delay technique is proposed. A voltage controlled delay line (VCDL) in the proposed frequency doubler compensates the group delay time mismatching between input and delayed signal. With the group delay time matching and waveform shaping using the adjustable Schmitt triggers, the unwanted fundamental component($f_0$) and the higher order harmonics such as third and fourth are diminished excellently. In result, only the doubled frequency component($2f_0$) appears dominantly at the output port. The frequency doubler is designed at 1.15 GHz of $f_0$ and fabricated with TSMC $0.18\;{\mu}m$ CMOS process. The measured output power at $2f_0$ is 2.67 dBm when the input power is 0 dBm. The obtained suppression ratio of $f_0,\;3f_0$, and $4f_0$ to $2f_0$ are 43.65, 38.65 and 35.59 dB, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.5
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• pp.513-520
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• 2003

In this paper, a novel design concept of frequency doubler using feedforward technique and DGS microstrip line is proposed. The feedforward loop plays a role of fundamental frequency suppression and DGS microstrip line suppresses over the 3rd order harmonic components. By using this new concept, the high suppression for the undesired signals could be achieved easily. The proposed technique is experimentally demonstrated in 1.87 GHz-to-3.74 GHz frequency doubler. The output power of -3 dBm at the frequency of 3.74 GHz(2f$\_$0/) is measured with 42.9 dB suppression of the fundamental frequency signal(f$\_$0/), 20.2 dB suppression of the 3rd harmonic signal(3f$\_$0/) and B9.7 dB suppression of the 4th harmonic signal(4f$\_$0/). The conversion loss of -2.34 dB ∼ -5.8 dB at the bandwidth of 100 MHz, the phase noise of -97.51 dB/Hz(＠10 kHz) were measured.

• Journal of Biomedical Engineering Research
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• v.23 no.1
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• pp.61-72
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• 2002

In this parer, a new harmonic imaging technique is Proposed and evaluated experimentally. In the Proposed method. a weighted chirp signal with a hanning window is transmitted. The RF samples obtained on each array element are individually compressed by correlating with the reference signal defined as the 2nd harmonic component($2f_0$) of a transmitted chirp signal generated in a square-law system. The correlator output will then consist of the compressed version of the $2f_0$ component generated in tissue and the crosscorrelation sequence of the fundamental($f_0$) and 2f$_{0}$components. The Proposed method uses the compressed $2f_0$ component to form an image. for which the crosscorrelation term should be suppressed below at least -50dB. The Proposed method has two process, 2f$_{0}$-correlation and $2f_0$-correlation(PI) . $2f_0$-correlation can successfully eliminate the $f_0$ component with a single transmit-receive events and therefore is more efficient than the conventional Pulse inversion method in terms of the frame rate. 2i)-correlation(Pl) Performs pulse compression after applying pulse inversion method for the 2nd harmonic image with high resolution and SNR. Another advantage of the proposed method is that the SNR of 2nd harmonic imaging can be improved without limitation by increasing the duration of the chirp signal. The proposed method was verified through both the computer simulations and actual experiments .ts .

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.611-614
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• 1998

윈도우즈 95와 같은 멀티미디어 환경 하에서 개인 신분 확인을 위한 방법은 비밀번호를 키보드로 입력받는 것이었으나, 본 논문에서는 음성을 이용하는 방법으로 기존의 방법이 기준패턴의 시간에 따라 변하는 특성을 보상하지 못한다는 단점을 보완하는 방법이다. 즉, 이를 위해 음성신호의 특징인 기본주파수와 제1포만트의 비율을 이용하여 기준패턴을 형성화하는 방법에 관한 것이다. 제안한 방법으로 실험한 결과, 98%의 전체 인식율을 얻게 되었고, 윈도우즈 환경에서 비밀번호 사용 대신 음성 사용에 대한 가능성을 보여 주었다.

• Speech Sciences
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• v.14 no.4
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• pp.251-260
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• 2007

The structure changes of the vocal folds are related to the fundamental frequencies (F0). In other words, the increasing in vocal fold length and thickness makes the result of dropping in the F0 during the mutational period. The purpose of this study was to investigate F0 of normal children's voice in mutational period. 360 children (180 boys and 180 girls) were participated in this experiment. The age was ranged from 11 to 16 years. The subjects were asked to produce sustained comer vowels (/a/ /i/ /u/) five times each and the data were analyzed using the MDVP of CSL. The result shows that the F0 are considerably decreased with age and reach to adults' F0 by 16 years in most cases. In particular, the F0 of male subjects were rapidly decreased between the ages from 12 ($226.98\;{\pm}\;19\;Hz$) to 13 years ($169.3\;{\pm}\;25\;Hz$), while the F0 of female subjects were slowly changed from the later period of 12 to 16 years old. This result may be used by the meaning of guideline and lead the basic data to differentiate between normal voice and voice disorder.

• The Journal of the Acoustical Society of Korea
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• v.30 no.4
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• pp.231-237
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• 2011

The purpose of this study is to examine the correlation between the preferred sensation type and speech sounds, especially on $F_0$ and the speech rates. Data for the sensation types and speech sounds were collected from 36 undergraduate and graduate students (17 male, 19 female). Subjects were asked to read a given text (400 syllables), describe a drawing, and give answers to some questions. We measured speakers' $F_0$ and speech rates. The results show that type V (Visual) has the correlation with the speech rates when type D (Digital) was ruled out, and type A (Auditory) has the correlation with the speech rates when type D was included. Furthermore, the analysis of the mean values of V, A, K (Visual, Auditory, Kinethetic) indicates that type V is characterized with faster speech rates and higher $F_0$ in all parts except for interview and the same is true for that of V, A, K, D (Visual, Auditory, Kinethetic, Digital) in all parts. In conclusion, this study proved that the preferred sensation type has the correlation with $F_0$ and speech rates. Based on the results of this study, $F_0$ and speech rates can be used to analyze the sensation types for individualized education as well as consultation. In addition, this study has great significance in that it lays a foundation for the study on the correlation between a preferred sensation type and speech sounds.

• Phonetics and Speech Sciences
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• v.11 no.3
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• pp.77-87
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• 2019

The study aimed to develop Speech Range Profile (SRP) and to examine and validate its clinical application. Forty-five participants without voice disorders aged 18-29 years were compared using SRP and Voice Range Profile (VRP). The authors developed the "Fire!" paragraph as a SRP task compromising 14 sentences including all Korean spoken phonemes and sentence types. To compare SRP and VRP results, the participants read the paragraph (reading) and counted from 21 to 30 (counting) as a part of SRP tasks, and produced a vowel /a/ from low to high frequencies (gliding) and a shortened form of the VRP as a part of VRP tasks. $F0_{max}$, $F0_{min}$, $F0_{range}$, $I_{max}$, $I_{min}$, and $I_{range}$ for each task were measured and compared, showing that $F0_{max}$, $F0_{min}$, $F0_{range}$, $I_{max}$, and $I_{range}$ were not different between reading and gliding. $I_{min}$, had the lowest value in counting. It is concluded that the newly developed SRP task, reading the "Fire" paragraph, can yield a maximum phonation range similar to that found by VRP. Therefore, it is expected that voice evaluation can be effectively performed in a relatively short time by applying SRP with the "Fire" paragraph, a functional utterance task, in place of VRP, which may be difficult to measure long term or in cases of severe voice disorders.