• Computers and Concrete
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• v.32 no.5
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• pp.475-486
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• 2023

Nondestructive evaluation (NDE) is an important task of civil engineering structure monitoring and inspection, but minor damage such as small cracks in local structure is difficult to observe. If cracks continued expansion may cause partial or even overall damage to the structure. Therefore, monitoring and detecting the structure in the early stage of crack propagation is important. The crack detection technology based on machine vision has been widely studied, but there are still some problems such as bad recognition effect for small cracks. In this paper, we proposed a deep learning method based on sweep signals to evaluate concrete surface crack with a width less than 1 mm. Two convolutional neural networks (CNNs) are used to analyze the one-dimensional (1D) frequency sweep signal and the two-dimensional (2D) time-frequency image, respectively, and the probability value of average damage (ADPV) is proposed to evaluate the minor damage of structural. Finally, we use the standard deviation of energy ratio change (ERVSD) and infrared thermography (IRT) to compare with ADPV to verify the effectiveness of the method proposed in this paper. The experiment results show that the method proposed in this paper can effectively predict whether the concrete surface is damaged and the severity of damage.

• Applied Science and Convergence Technology
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• v.24 no.6
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• pp.284-288
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• 2015

Anionic small molecules are hard to penetrate the cell membranes because of their negative charges. Encapsulation of small molecules into liposome particles can provide target specific delivery of them. In our previous study, siRNA could be efficiently encapsulated into liposome particles using an asymmetric preparation method of liposomes. In this study, the same method was applied for encapsulation of small anionic fluorescent chemicals such as calcein and indocyanine green (ICG). More than 90% fluorescent chemicals were encapsulated in the asymmetric liposome particles (ALPs). No intracellular fluorescent signal was observed in the tumor cells treated with the unmodified calcein/ALPs and ICG/ALPs, whereas the surface modification with a cell-penetrating polyarginine peptide (R8 or R12) allows cellular uptake of the ALPs. The results demonstrate that the ALPs encapsulating small anionic drugs will be useful for target-specific delivery after modification of target-specific ligands.

• Transactions on Electrical and Electronic Materials
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• v.9 no.6
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• pp.260-264
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• 2008

The operational characteristics of superconducting amplifier using vortex flux flow were analyzed from an equivalent circuit in which its current-voltage characteristics for the vortex motion in YBCO microbridge were reflected. For the analysis of operation as an amplifier, dc bias operational point for the superconducting amplifier is determined and then ac operational characteristics for the designed superconducting amplifier were investigated. The variation of transresistance, which describes the operational characteristics of superconducting amplifier, was estimated with respect to conditions of dc bias. The current and the voltage gains, which can be derived from the circuit for small signal analysis, were calculated at each operational point and compared with the results obtained from the numerical analysis for the small signal circuit. From our paper, the characteristics of amplification for superconducting flux flow transistor (SFFT) could be confirmed. The development of the superconducting amplifier applicable to various devices is expected.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.7
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• pp.42-48
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• 1994

In this paper, a low power and high speed flash Analog-to-Digital Converter using current-mode concept is proposed. Current-mode approach offers a number of advantages over conventional voltage-mode approach, such as lower power consumption small chip area improved accuracy etc. Rescently this concept was applied to algorithmic A/D Converter. But, its conversion speed is limited to medium speed. Consequently this converter is not applicable to the high speed signal processing system. This ADC is fabricated in 1.2um double metal CMOS standard process. This ADC's conversion time is measured to be 7MHz, and power consumption is 2.0mW, and differential nonlinearity is less than 1.14LSB and total harmonic distortion is -50dB. The active area of analog chip is about 350 x 550u$m^2$. The proposed ADC seems suitable for a single chip design of digital signal processing system required high conversion speed, high resolution small chip area and low power consumption.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.2
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• pp.1-10
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• 1999

Direct extraction of FET's small signal model parameters needs predetermined parasitic elements usually obtained under forward cold FET conditionl This paper derives analytic intrinsic model for cold FET's and shows that normal cold FET condition can replace forward cold FET condition for extracting parasitic elements. Then, we track the error of hot FET's small signal model bounded by the cold FET condition and examine the validness of cold parasitic resistances by checking the existence of the error minimum.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.82-87
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• 1994

Signal transduction through G protein-coupled receptors comprises three functional components, a receptor, a G protcin and a effector protein. Work over the last sevcral ycars has led to the characterization or virtually all of the components or these systems. what has come out or those studies is that these mechanisms of signal transduction are pervasive in nature being found in mammalian and avian species, as well as lower organisms such as yeast and slime mold. It is known that G protein-coupled receptors mediate the action of such diverse molecules such as small hormones and neurotransmitters, small peptide molecules as well as glycoprotein hormones and various sensory perceptions such as light, olfaction and most likely taste.

• Journal of Electrical Engineering and Technology
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• v.2 no.4
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• pp.428-433
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• 2007

This paper describes the new eigenvalue algorithm exploiting the Implicit Restarted Arnoldi Method (IRAM) and its application to power systems. IRAM is a technique for combining the implicitly shifted mechanism with a k-step Arnoldi factorization to obtain a truncated form of the implicitly shifted QR iteration. The numerical difficulties and storage problems normally associated with the Arnoldi process are avoided. Two power systems, one of which has 36 state variables and the other 150 state variables, have been tested using the ARPACK program, which uses IRAM, and the eigenvalue results are compared with the results obtained from the conventional QR method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1703-1707
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• 2008

Low frequency oscillation of inter-area system is important problem in power system areas because the operation conditions of power system depend on it. Generally, the analysis of the problem is used by small signal stability. Especially, the analysis results are affected by decision of load models. In this paper, the effect of the analysis results was studied according to load component characteristics. ZIP model, popular in large-scaled power system analysis, was used as the load model. Many cases were studied according to the combination of ZIP model in inter-area system.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.2
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• pp.137-142
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• 2003

Two existing continuous-time models for the current-mode control have presented noticeable differences in their small-signal predictions. As an attempt to clarify the origin of these disparities, this paper presents an alternative way of deriving a continuous-time model for the current-model control. The results of this paper would provide insights to comprehend the dissimilarity in the modeling method and final results of the earlier models of current-mode control models.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.550-553
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• 2001

In this study, unity current gain frequency f$\_$T/ of GaAs MESFET is predicted with different temperatures up to 400 $^{\circ}C$. Temperature dependence parameters of the device including intrinsic carrier concentration n$\_$i/ effective mass, depletion width are considered to be temperature dependent. Small signal parameters such as gate-source, gate dran capacitances C$\_$gs/ C$\_$gd/ are correlated with transconductance g$\_$m/ to predict the unity current gain frequency. The extrinsic capacitance which plays an important roles in high frequency region has been taken into consideration in evaluating total capacitance by using elliptic integral through the substrate. From the results, f$\_$T/ decreases as the temperature increases due to the increase of small signal capacitances and the mobility degradation. Finally the extrinsic elements of capacitances have been proved to be critical in deciding f$\_$T/ which are originated from the design rule of the device.