• The Journal of the Convergence on Culture Technology
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• v.4 no.3
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• pp.287-291
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• 2018

The CNTFET, which is attracting attention as a next-generation semiconductor device, can obtain ballistic or near-ballistic transport at a lower voltage than that of conventional MOSFETs by depositing CNTs between the source and drain of the device. In order to increase the performance of the CNTFET, a large number of CNTs must be deposited at a high density in the CNTFET. Thus, various manufacturing processes to increase the density of the CNTs have been developed. Recently, the Directional Shrinking Transfer Method was developed and showed that the current density of the CNTFET device could be increased up to 150 uA/um. So, this method enhances the possibility of implementing a CNTFET-based integrated circuit. In this paper, we will discuss how to evaluate the performance of the CNTFET device compared to a MOSFET at the circuit level when the CNTFET is fabricated by the Directional Shrinkage Transfer Method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.2
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• pp.147-152
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• 2015

We designed, fabricated, and tested the capacitive microsensors for skin piloerection monitoring. The performance of the skin piloerection monitoring sensor was characterized using the artificial bump, representing human skin goosebump; thus, resulting in the sensitivity of $-0.00252%/{\mu}m$ and the nonlinearity of 25.9 % for the artificial goosebump deformation in the range of $0{\sim}326{\mu}m$. We also verified two successive human skin piloerection having 3.5 s duration on the subject's dorsal forearms, thus resulting in the capacitance change of -6.2 fF and -9.2 fF compared to the initial condition, corresponding to the piloerection intensity of $145{\mu}m$ and $194{\mu}m$, respectively. It was demonstrated experimentally that the proposed sensor is capable to measure the human skin piloerection objectively and quantitatively, thereby suggesting the quantitative evaluation method of the qualitative human emotional state for cognitive human-machine interfaces applications.

• 전기의세계
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• v.13 no.4
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• pp.1-9
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• 1964

수차발전기에서 이상진동이 발생하였을 경우 일반적인 진동판별법을 서술하기로 한다. 실제로 부디치는 진동문제를 취급하여 보면 단순한 원인에 의한 것 뿐만아니라 여러가지 원인이 중첩되어 복잡한 비선형적인 현상이 나타날 경우가 많다. 원동기측 및 피동기측의 회전자급 고정자의 각각에 진동을 발생하는 다수의 요인이 있고 또 각각의 진동원인들의 상호간의 영향력이 작용하여 복잡한 진동현상을 가지고 있어서 그 원인을 판별하기가 용이한 일이 아니다. 이러한 진동원인중 주 되는 몇가지 원인을 찾아내기 위하여는 진동특성에 관한 충분한 이해와 적절한 측정장치를 선택할 필요가 있다.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.1
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• pp.45-52
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• 2020

Hypertension often leads to cardiovascular disease and kidney disease, and hypertention is an important worldwide problem. Body mass index (BMI) has an important role for raising blood pressure. Further, hypertension can be affected by both environmental factors and genetic factors. Many single nucleotide polymorphisms have been associated with hypertension. Genome wide association study (GWAS) is a method of confirming a new locus of increasing the risk of disease, and GWAS has confirmed several single nucleotide polymorphisms (SNPs) that are associated with high blood pressure. This study analyzed the relationship between systolic blood pressure, diastolic blood pressure and SNP of the ATP2B1 gene in 994 Koreans. SNPs that showed the highest statistical significance with systolic and diastolic blood pressures were selected on the multiple linear regression analysis. One-way analysis of variance for systolic and diastolic blood pressures was performed, and multiple logistic regression analysis was performed on the risk of hypertension. The P values were two-tailed, and P<0.05 was considered significant. Four SNPs were associated with systolic blood pressure and six SNPs were associated with diastolic blood pressure. In addition, a genotype-based analysis showed significant odds ratios for the risk of hypertension in older men (adjusted OR, 5.743; 95% CI, 1.173~28.121; P=0.031). This study suggests that the ATP2B1 variants affect both the systolic and diastolic blood pressure.

• Journal of the Korean Society for Railway
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• v.17 no.4
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• pp.270-280
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• 2014

In this study, to examine the causes of cracks in continuously reinforced concrete tracks (CRCTs) and the main factors affecting cracking, a field survey on the status of cracks and crack patterns in the Gyeong-bu high speed line was conducted, and the crack patterns of CRCT due to the temperature difference between the top of the slab (TCL) and the bottom of the subbase (HSB) and the drying shrinkage of concrete were predicted by a nonlinear finite element model considering the structure of CRCT. The results of the numerical analysis show that cracks will be developed at the interface between the sleeper and the TCL, and under the sleeper due to the temperature difference and concrete shrinkage. This corresponds well to the crack locations found in the field. Also, it is found that the most significant factors are the coefficient of thermal expansion with respect to the temperature difference, and the drying shrinkage strain with respect to shrinkage. According to the results, the reinforcement ratio should be carefully determined considering the structures of CRCT because the crack spacing is not always proportional to the reinforcement ratio due to the sleepers embedded in the TCL.

• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.605-609
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• 2004

Blood pressure (BP) is one of the important physiological parameters for diagnosing cardiovascula diseases by means of noninvasive method. Existing noninvasive methods for measuring arterial BP have to use cuff and difficult in measuring arterial BP continuously. Systolic blood pressure (SBP) and pulse transit time (PTT) have a kind of inverse relationship. We acquired PTT data when subjects were in relaxation and also after exercise. We performed the linear regression analysis for making the regression equations for each subject and the regression equation for all subjects. We compared the estimated SBP with the measured SBP to check the accuracy of our regression equations. From the result, the regression equations for each subject was appropriate according to the American National Standards Institute of the Association of the Advancement of Medical Instrument (ANSI/AAMI) which says that BP devices should have ±5mmHg mean of error and 8mmHg standard deviation of error. However, the regression equation for all subjects was not proper to ANSI/AAMI recommendation. The result means that, without cuff, we can continuously estimate each subject's SBP through PTT and indivisual calibration.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.2
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• pp.227-235
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• 2010

This paper introduces the design of a bridge transport system with a telescopic tube for positioning equipment to perform remote handling tasks in a radioactive facility. It consists of an extensible and retractable telescopic tube assembly for z-direction motion, a cabling system for management of power and signal cables, and a trolley system for transverse motion and accommodating servo drives. The working environment for the bridge transport system with the telescopic tube requires strict geometrical constraints, including a short height, short telescopic tube length when retracted, and a long stroke. These constraints were met by solving a nonlinear programming problem involving the optimal dimensions. This paper introduces a cabling system for effective management of cables with changeable lengths to accommodate telescopic motions and a selection guide for servo drives that are sufficient to drive the system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.1
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• pp.83-95
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• 1999

Wavelet transform has localization for time or frequency. It is useful to analyze a nonstationary signal. Basic function on wavelet transform is generated dilating and translating the original wavelet(mother wavelet). In this paper, time-frequency analysis method using linear combination wavelet transform is proposed. And it is applied to diagnostic monitoring system using the proposed linear combination wavelet transform. The stationary and nonstationary signal is used linear chirp signal, fan noise signal, a sinusoid signal from revolution body, electronic signal. Transform applied to signal analysis use fast Fourier transform (FFT), Daubechies, Haar and proposed linear combination method. The result of time-frequency analysis using linear combination wavelet transform is suited for portraying nonstationary time signal as well as stationary signal. Also the diagnostic monitoring system carry out the effective the signal analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.1
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• pp.49-62
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• 1994

An analysis method for the time-dependent nonlinear analysis of segmentally erected planar prestressed concrete cable-stayed bridges was described. To account for the time-dependent effects, load history, creep, shrinkage. aging of concrete and relaxation of prestress were considered. Changes in boundary conditions and loads, installing and removing frame elements, stressing, restressing and removing cables and prestressing tendons were incorporated for modeling segmental erection operations. One typical example on segmentally erected prestressed concrete cable-stayed bridge was presented to illustrate the analysis method. Results of this example show that it is important to follow the development of stresses and deformations at all stages of construction to predict the true response of the bridge through its various load history.

• Korean Journal of Optics and Photonics
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• v.15 no.2
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• pp.100-103
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• 2004

A systematic method for tunable dispersion compensation based on chirped fiber Bragg gratings without a center wavelength shift is proposed. The specially designed mechanical rotator can flexibly control the chirping ratio along the fiber grating and the corresponding dispersion value. The group delay can be linearly controllable since the proposed method can induce a linear strain gradient with the rotation angle change. The dispersion value could be controlled from 228.04 ㎰/nm to 1430.7 ㎰/nm with small center wavelength shift, which was less than 0.03 nm.