• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.430-433
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• 2001

The $0.96MgTiO_{3}-0.04SrTiO_{3}+xCe(x=0{\sim}1.6wt%)$ ceramics were fabricated by the conventional mixed oxide method. The sintering temperature and time were $1300^{\circ}C$, 2hr., respectively. From the X-ray diffraction patterns, it was found that the perovskite $SrTiO_{3}$ and ilmenite $MgTiO_{3}$ structures were coexisted in the $0.96MgTiO_{3}-0.04SrTiO_{3}+xCe(x=0{\sim}1.6wt%)$ ceramics. The dielectric constant$(\varepsilon_{r})$ was increased with addition of Ce. The temperature coefficient of resonant frequency$(\Gamma_{f})$ was gradually varied from positive value to the negative value with increasing the Ce. The temperature coefficient of resonant frequency of the $0.96MgTiO_{3}-0.04SrTiO_{3}+0.2Ce$ ceramics was near zero, where the dielectric constant, quality factor, and $\Gamma_{f}$ were 20.68, 50,272 and ${-0.5ppm/^{\circ}C}$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.430-433
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• 2001

The 0.96MgTiO$_3$-0.04SrTiO$_3$+xCe(x=0∼1.6 wt%) ceramics were fabricated by the conventional mixed oxide method. The sintering temperature and time were 1300$^{\circ}C$, 2hr., respectively. From the X-ray diffraction patterns, it was found that the perovskite SrTiO$_3$ and ilmenite MgTiO$_3$ structures were coexisted in the 0.96MgTiO$_3$-0.04SrTiO$_3$+xCe(x=0∼1.6 wt%) ceramics. The dielectric constant($\varepsilon$$\sub$r/) was increased with addition of Ce. The temperature coefficient of resonant frequency($\tau$$\sub$f/) was gradually varied from positive value to the negative value with increasing the Ce. The temperature coefficient of resonant frequency of the 0.96MgTiO$_3$-0.04SrTiO$_3$+0.2Ce ceramics was near zero, where the dielectric constant, quality factor, and $\tau$$\sub$f/ were 20.68, 50, 272 and -0.5pm/$^{\circ}C$, respectively.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.8 no.1
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• pp.44-48
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• 1997

Anatomic and physiological changes of the larynx with advancing age result in morphologic changes of the vocal fold and reduced control of the phonatory mechanism in elderly individuals and are reflected in increased unstability of fundamental frequency (Fo). The purpose of this study is to increase current understanding of acoustic and stroboscopic characteristics of normal elderly persons voices. First, phonated /a/ vowel productions by 40 normal adults (20 to 40 years, 20 men and 20 women) and 40 normal elderly persons (60 to 80 years,20 men and 20 women) were analyzed, using CSL (model 4300B) acoustic analysis software, to obtain acoustic measures related to fundamental frequency stability nd vocal resonance characteristics. Second, stroboscopic images of the vocal fold behavior in all subjects were analyzed by experienced specialists. In the men, fundamental frequency variation (vFe) (p＜0.01), jitter. (p＜0.05), and shimmer (p＜0.05) for the older group were significantly higher than the value for the adult group. In the stroboscopic findings, edema of vocal fold had a significant finding in aged men (15%). In the women, vFo (p＜0.05), jitter (p＜0.05), and noise to harmonic ratio (NHR) (p＜0.05) for the older group were significantly higher than the value for e adult group and first formant frequency (F1) (p＜0.01) and second formant frequency (F2) (p＜0.01) for. the older group were significantly lower than the value for the adult group. In the stroboscopic findings, vocal fold atrophy had a significant finding in aged women (25%). Frequency stability, as reflected by vFo, jitter, shimmer, and NHR, decreases with advancing age in men and women and spectral analysis of phonated /a/ vowel productions reveals the lowering of the frequency of F1 and second F2 with advancing age, especially in aged women. Change in the mass of vocal folds, due to atrophy or edema, is considered to be the greatest factor in these acoustic changes.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.1
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• pp.154-161
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• 2001

We have treated polyester fabric with $CF_4,\;C_2F_6,\;SF_6\;and\;C_3F_6$ glow discharge plasmas to develop functional fabrics which preserve moisture transportation and water proofing nature. Modified properties were evaluated by water vapor permeation rate and breakthrough water pressure. The change of surface morphology was observed by SEM. Fiber interstice of the plasma treated fabric was calculated as $0.32{\mu}{\textrm}{m}$, and this value was sufficiently ideal as water repellent material. The moisture transportation of ${CF_4}-treated$ fabric was good as much as untreated fabric, and those of $C_2$F(sub)6-treated, SF(sub)6-treated fabrics were reduced by 1~3%, and that of ${C_3F_6}-treated$ fabric was reduced by 15%. The best treatment condition were 0.06 torr 120 seconds in $CF_4$, 0.05 torr 30 seconds in $SF_6$, 0.08~0.15 torr 90 seconds in $SF_6$ and 0.1 torr 45 seconds in $C_3F_6$ respectively. The grade of moisture transportation effect was $CF_4>C_2F_6>SF_6>>C_3F_6$, and water proofing effect was $C_2F_6{\approx}CF_4>C_3F_6>SF_6$. It was observed by SEM that the thin film was formed on the surface of the treated substrate by the fluorocarbon plasma treatment.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.8
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• pp.9-16
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• 2000

MOS transistors are fabricated and evaluated for RF IC applications such as mobile communication systems using 0.35m CMOS process. Characteristics of MOSFETs are analyzed at various channel length, width and bias conditions. From the analysis, cut-off frequency ($f_T$) is independent on channel width but maximum oscillation frequency ($f_{max}$) tends to derease as the channel width increases. As channel length increases, $f_T$ and fmax decrease. $f_T$ is 22GHz and fmax is 28GHz at its maximum value. High frequency noise performance is improved with larger channel width and smaller channel length at same bias conditions. NFmin at 2GHz is 0.45dB as a minimum value. From the evaluation, MOSFETs designed using 0.35m CMOS process demonstrated a full potential for the commercial RF ICs for mobile communication systems near 2GHz. And optimization methods of the CMOS transistors for RF applications are presented in this paper.

• Journal of applied mathematics & informatics
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• v.27 no.5_6
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• pp.1211-1220
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• 2009

In this paper, we consider the multipoint boundary value problem for the one-dimensional p-Laplacian $({\phi}_p(u'))'$(t)+q(t)f(t,u(t),u'(t))=0, t $\in$ (0, 1), subject to the boundary conditions: $u(0)=\sum\limits_{i=1}^{n-2}{\alpha}_iu({\xi}_i),\;u(1)=\sum\limits_{i=1}^{n-2}{\beta}_iu({\xi}_i)$ where $\phi_p$(s) = $|s|^{n-2}s$, p > 1, $\xi_i$ $\in$ (0, 1) with 0 < $\xi_1$ < $\xi_2$ < $\cdots$ < $\xi{n-2}$ < 1 and ${\alpha}_i,\beta_i{\in}[0,1)$, 0< $\sum{\array}{{n=2}\\{i=1}}{\alpha}_i,\sum{\array}{{n=2}\\{i=1}}{\beta}_i$<1. Using a fixed point theorem due to Bai and Ge, we study the existence of at least three positive solutions to the above boundary value problem. The important point is that the nonlinear term f explicitly involves a first-order derivative.

• The KIPS Transactions:PartA
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• v.12A no.2 s.92
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• pp.95-102
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• 2005

The Newton-Raphson iterative algorithm for finding a floating point reciprocal which is widely used for a floating point division, calculates the reciprocal by performing a fixed number of multiplications. In this paper, a variable latency Newton-Raphson's reciprocal algorithm is proposed that performs multiplications a variable number of times until the error becomes smaller than a given value. To find the reciprocal of a floating point number F, the algorithm repeats the following operations: '$'X_{i+1}=X=X_i*(2-e_r-F*X_i),\;i\in\{0,\;1,\;2,...n-1\}'$ with the initial value $'X_0=\frac{1}{F}{\pm}e_0'$. The bits to the right of p fractional bits in intermediate multiplication results are truncated, and this truncation error is less than $'e_r=2^{-p}'$. The value of p is 27 for the single precision floating point, and 57 for the double precision floating point. Let $'X_i=\frac{1}{F}+e_i{'}$, these is $'X_{i+1}=\frac{1}{F}-e_{i+1},\;where\;{'}e_{i+1}, is less than the smallest number which is representable by floating point number. So, $X_{i+1}$ is approximate to $'\frac{1}{F}{'}$. Since the number of multiplications performed by the proposed algorithm is dependent on the input values, the average number of multiplications per an operation is derived from many reciprocal tables $(X_0=\frac{1}{F}{\pm}e_0)$ with varying sizes. The superiority of this algorithm is proved by comparing this average number with the fixed number of multiplications of the conventional algorithm. Since the proposed algorithm only performs the multiplications until the error gets smaller than a given value, it can be used to improve the performance of a reciprocal unit. Also, it can be used to construct optimized approximate reciprocal tables. The results of this paper can be applied to many areas that utilize floating point numbers, such as digital signal processing, computer graphics, multimedia scientific computing, etc.

• Journal of applied mathematics & informatics
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• v.27 no.1_2
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• pp.205-215
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• 2009

Sufficient conditions for the existence of at least one solution of the boundary value problems for higher order nonlinear difference equations $\{{{{{\Delta^n}x(i-1)=f(i,x(i),{\Delta}x(i),{\cdots},\Delta^{n-2}x(i)),i{\in}[1,T+1],\atop%20{\Delta^m}x(0)=0,m{\in}[0,n-3],}\atop%20\Delta^{n-2}x(0)=\phi(\Delta^{n-1}(0)),}\atop%20\Delta^{n-1}x(T+1)=-\psi(\Delta^{n-2}x(T+1))}\$. are established.

• Speech Sciences
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• v.15 no.1
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• pp.87-98
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• 2008

This study compares the pitch production of children using cochlear implants (CI) with that of children with normal hearing. Twenty subjects from six to eight years old participated in the study. Three kinds of sentences were read and analyzed using Visi-Pitch $\blacktriangleright$(KAY Elemetrics, Model 3300). There were no considerable differences between the two groups regarding pitch, mean fundamental frequency (F0) and pitch range. In the cases of the slope value of F0 and duration, however, there were significant differences. Thus, it is concluded that duration and pitch control can be crucial factors in determining the intonation treatment of the children with cochlear implants.

• Korean journal of food and cookery science
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• v.31 no.1
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• pp.62-71
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• 2015

The purpose of this study was to evaluate the changes on the characteristics of the oxidative stability of Tenebrio molitor larvae during cold storage at $4^{\circ}C$. Pretreatment for T. molitor larvae was designed into three methods: raw (R), freeze-dried (F.D.), and pan-fried (P.F.). The water content of the raw sample (61.46%) was higher than those of other samples (F.D.: 5.02%, P.F.: 3.67%) and its high water content was expected to facilitate the oxidation of the raw sample. In our results, the peroxide value and the carbonyl value of all of the samples increased and the raw sample, after storage for 18 day, showed the highest value. The pan-fried sample had no significant increase in its lactic acid content, acid value, and thiobarbituric acid value; whereas those values were increased in the raw sample and the freeze-dried sample (p<0.05). The browning reaction was more progressed in the pan-fried sample than other samples at 0 day, but there was no significant change during the storage. The raw sample and the freeze-dried sample had their browning indexes increase with the increasing storage period (p<0.05). The pan-fried sample produced less oxidation products than the freeze-dried sample, indicating that the unheated sample was more susceptible to oxidation than the heated samples. In conclusion, heating treatment and low water content would be effective for improving the safety and stability of T. molitor larvae during cold storage.