• ETRI Journal
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• v.36 no.6
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• pp.924-930
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• 2014

This paper presents a $0.13{\mu}m$ CMOS 3-level envelope delta-sigma modulation (EDSM) RF signal generator, which synthesizes a 2.6 GHz-centered fully symmetrical 3-level EDSM signal for high-efficiency power amplifier architectures. It consists of an I-Q phase modulator, a Class B wideband buffer, an up-conversion mixer, a D2S, and a Class AB wideband drive amplifier. To preserve fast phase transition in the 3-state envelope level, the wideband buffer has an RLC load and the driver amplifier uses a second-order BPF as its load to provide enough bandwidth. To achieve an accurate 3-state envelope level in the up-mixer output, the LO bias level is optimized. The I-Q phase modulator adopts a modified quadrature passive mixer topology and mitigates the I-Q crosstalk problem using a 50% duty cycle in LO clocks. The fabricated chip provides an average output power of -1.5 dBm and an error vector magnitude (EVM) of 3.89% for 3GPP LTE 64 QAM input signals with a channel bandwidth of 10/20 MHz, as well as consuming 60 mW for both channels from a 1.2 V/2.5 V supply voltage.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.6
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• pp.265-270
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• 2002

The determination of DNA hybridization reaction can apply the molecular biology research, clinic diagnostics, bioengineering, environment monitoring, food science and application area. So, the improvement of DNA hybridization detection method is very important for the determination of this hybridization reaction. Several molecular biological techniques require accurate predictions of matched versus mismatched hybridization thermodynamics, such as PCR, sequencing by hybridization, gene diagnostics and antisense oligonucleotide probes. In addition, recent developments of oligonucleotide chip arrays as means for biochemical assays and DNA sequencing requires accurate knowledge of hybridization thermodynamics and population ratios at matched and mismatched target sites. In this study, we report the characteristics of the probe and matched, mismatched target oligonucleotide hybridization reaction using thermodynamic method. Thermodynamic of 5 oligonucleotides with central and terminal mismatch sequences were obtained by measured UV-absorbance as a function of temperature. The data show that the nearest-neighbor base-pair model is adequate for predicting thermodynamics of oligonucleotides with average deviations for $\Delta$H$^{0}$ , $\Delta$S$^{0}$ , $\Delta$G$_{37}$ $^{0}$ and T$_{m}$, respectively.>$^{0}$ and T$_{m}$, respectively.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.2
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• pp.209-215
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• 2022

This study aims to analyze the livelihood resources and income diversification of informal recyclers in the Mekong River Delta (MRD). The multiple linear regression model was applied to determine income diversification and total household income with the sustainable livelihood analysis framework developed by the United Kingdom Department for International Development (2000), including human resources, physical resources, natural resources, financial resources, and social resources. The results indicated that up to 25% of itinerant waste buyers worked on average more than 7.3 hours/day, which was higher than the urban near-poor level regulated by the Vietnam government. The results of the regression model revealed that total households' income was affected by the factors of health status, gender, urban location type 1, the amount of potential savings, and informal credit participation, while the factors of health status, urban location, the amount of potential savings, and informal credit participation have the effect of diversifying farm household income. Thus, if the informal waste recycling sector is supported and regulated by proper government management, it will not only help poor households diversify their income, but it will also help poor households diversify their income, particularly women's income, which is vulnerable and lower than male income in the MRD.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.2
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• pp.47-52
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• 2003

117 undergraduate ophthalmic optics students volunteered to participate in this study. They ranged in age from 19 to 26 years. Subject, had best corrected visual acuity of at least 1.0 in both eyes, no strabismus, no amblyopia, and no history of ocular surgery. 37 subjects are esphoria and 25 subjects are $3{\Delta}$ and less, and the rest of 12 subjects show more $4{\Delta}$. Average phoria amount is $2.96{\Delta}$ at far distance and $1.08{\Delta}$ at near distance, respectively. The variation of phoria amount in far and near distance, unchanging subjects are 3, 8 subjects are increase esophoria amount, and 26 subjects are phoria amount decreasing or appear exophoria. The reason of esophoria amount is decreasing in near distance, and the results are convergence burden decreases. At positive relative convergence, the expected value in far distance, blurred point is 7, break point is 16, and recovery point is 12. And negative relative convergence, break point is 7 and recovery point is 13, respectively. Moreover, at positive relative convergence, the expected value in near distance is blurred point is 8, break point is 7 and recovery point is 22. And negative relative convergence, blurred point is 2, break point is 8 and recovery point is 12, respectively.

• Journal of the Korean Chemical Society
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• v.61 no.1
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• pp.29-33
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• 2017

Formation of Au particles in nonstoichiometric $Cu_{2-x}{^I}Cu{_2}^{II}O_{3-{\delta}}$ ($x{\approx}0.20$; ${\delta}{\approx}0.10$) oxide from aniline + hydrochloric acid mixtures and chloroauric acid in the ratios 30 : 1; 60 : 1; 90 : 1 (S1-S3) by volume and 0.01 mol of copper acetate, $Cu(OCOCH_3)_2.H_2O$, in each case is performed by sol-gel growth. Powder x-ray diffraction (XRD) results show Au particles are dispersed in tetragonal nonstoichiometric dicopper (I) dicopper (II) oxides, $Cu_{2-x}{^I}Cu{_2}^{II}O_{3-{\delta}}$ ($x{\approx}0.20$; ${\delta}{\approx}0.10$). Average crystallite sizes of Au particles determined using Scherrer equation are found to be in the approximate ranges ${\sim}85-140{\AA}$, ${\sim}85-150{\AA}$ and ${\sim}80-150{\AA}$ in S1-S3, respectively which indicate the formation of Au nano-micro size particles in $Cu_{2-x}{^I}Cu{_2}^{II}O_{3-{\delta}}$ ($x{\approx}0.20$; ${\delta}{\approx}0.10$) oxides. Hysteresis behaviour at 300 K having low loop areas and magnetic susceptibility values ${\sim}5.835{\times}10^{-6}-9.889{\times}10^{-6}emu/gG$ in S1-S3 show weakly ferromagnetic nature of the samples. Broad and isotropic electron paramagnetic resonance (EPR) lineshapes of S1-S4 at 300, 77 and 8 K having $g_{iso}$-values ${\sim}2.053{\pm}0.008-2.304{\pm}0.008$ show rapid spin-lattice relaxation process in magnetic $Cu^{2+}$ ($3d^9$) sites as well as delocalized electrons in Au ($6s^1$) nano-micro size particles in the $Cu_{2-x}{^I}Cu{_2}^{II}O_{3-{\delta}}$ ($x{\approx}0.20$; ${\delta}{\approx}0.10$) oxides. Broad and weak UV-Vis diffuse reflectance optical absorption band ~725 nm is assigned to $^2B_{1g}{\rightarrow}^2A_{1g}$ transitions, and the weak band ~470 nm is due to $^2B_{1g}{\rightarrow}^2E_g$ transitions from the ground state $^2B_{1g}$(${\mid}d_{x^2-y^2}$>) of $Cu^{2+}$ ($3d^9$) ions in octahedral coordination having tetragonal distortion.

• The Journal of the Acoustical Society of Korea
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• v.26 no.3E
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• pp.87-96
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• 2007

In this paper we propose a new noise reduction algorithm for stationary and nonstationary noisy environments. Our algorithm classifies the speech and noise signal contributions in time-frequency bins, and is not based on a spectral algorithm or a minimum statistics approach. It relies on calculating the ratio of the standard deviation of the noisy power spectrum in time-frequency bins to its normalized time-frequency average. We show that good quality can be achieved for enhancement speech signal by choosing appropriate values for ${\delta}_t\;and\;{\delta}_f$. The proposed method greatly reduces the noise while providing enhanced speech with lower residual noise and somewhat higher mean opinion score (MOS), background intrusiveness (BAK) and signal distortion (SIG) scores than conventional methods.

• Economic and Environmental Geology
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• v.19 no.spc
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• pp.131-138
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• 1986

Hydrogen and oxygen isotope ratios of thirteen of the under 2 micron size fraction of the montmorillonites were measured. The oxygen isotopic compositions of these samples range from + 17.0 to +25.1 permil and the hydrogen isotope compositions range from -47.5 to -65.8 permil with an average standard deviation of 0.7 and 2.7 permil, respectively. The oxygen isotope compositions show a positive relationship with stratigraphy whereas the hydrogen isotope compositions do not. It suggest that the montmorillonite attained isotopic equilibrium at the maximum burial depth and ratained their oxygen isotope composition on subsequent uplift. Possibilities of montmorillonite formation by weathering or hydrothermal alteration of volcanic material are eliminated by the ${\delta}D$ and ${\delta}^{18}O$ values of these samples. Calculated formation temperature lie between 29 to $80^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.697-700
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• 2001

In this paper, the structural and electrical properties of the Sr$_{1-x}$ Ca$_{x}$TiO$_3$ (0$\leq$x$\leq$0.2) (0$\leq$r$\leq$0.2)-based grain boundary layer ceramics were investigated by X-ray, SEM and V-I system. Increasing the Ca content, the average grain size and the lattice constant were decreased. The relative density of all specimens was >96%. The 2nd phase formed by thermal diffusing from the surface lead to a very excellent electrical properties, that is, $\varepsilon$$_{r}$>50000, tan$\delta$<0.05, $\Delta$C< $\pm$ 10%.\pm$ 10%.%.

• Speech Sciences
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• v.15 no.3
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• pp.7-15
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• 2008

This paper proposes the method to extract new feature vectors using the difference between the cepstrum for static characteristics and delta cepstrum for dynamic characteristics in speaker recognition (SR). The difference vector (DV) which it proposes from this paper is containing the static and the dynamic characteristics simultaneously at the intermediate characteristic vector which uses the deference between the static and the dynamic characteristics and as the characteristic vector which is new there is a possibility of doing. Compared to the conventional method, the proposed method can achieve new feature vector without increasing of new parameter, but only need the calculation process for the difference between the cepstrum and delta cepstrum. Experimental results show that the proposed method has a good performance more than 2.03%, on average, compared with conventional method in speaker identification (SI).

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1384-1386
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• 2001

In this paper, the structural and electrical properties of the $Sr_{1-x}Ca_xTiO_3$($0{\leq}x{\leq}0.2$)-based grain boundary layer ceramics were investigated by X-ray, SEM and V-I system. Increasing content of Ca, the average gram size and the lattice constant were decreased. The relative density of all specimens was > 96%. The 2nd phase formed by thermal diffusing from the surface lead to a very excellent electrical properties, that is, ${\varepsilon}_r$ > 50000, tan${\delta}$ < 0.05, $\Delta$C < ${\pm}$ 10%.