• Journal of Sensor Science and Technology
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• v.5 no.5
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• pp.11-20
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• 1996

In this paper, the characteristics of therapy radiation diode sensors have been studied by using therapy radiation from the MM22 microtron accelerator. The linearity, reproducibility and error ratio were measured for feasibility as a radiation detector. Energy dependence, sensitivity change after a amount of irradiation and output value according to a number of diodes were also measured for same purpose. We have formed pulse shaping of diode signal with nuclear instruments for portal image reconstruction. The percent depth dose ratio according to field size and depth was compared with that of the detector of a ion chamber. Using thirteen silicon diodes, we can directly read diode outputs on a computer monitor after A/D conversion with 16 channels analog to digital conversion board with 12 bit resolution. The possibility for portal image with diodes has been suggested from output comparison between output value with a human phantom and that without a human phantom.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.431-438
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• 2017

In this paper, the abdomen ECG(AECG) is employed to measure the mother's ECG instead of the conventioanl thoracic ECG measurement. The fetus ECG signal can be extracted from the AECG using an algorithm that utilizes the mobile fetal ECG measurement platform, which is based on the BLE (Bluetooth Low Energy). The algorithm has been implemented by using a replacement processor processed directly from the platform BLE instead of the large statistical data processing required in the ICA(Independent component analysis). The proposed algorithm can be implemented on a mobile BLE wireless ECG system hardware platform to process the maternal ECG. Wireless technology can realize a compact, low-power radio system for short distance communication and the IOT(Intenet of Things) enables the transmission of real-time ECG data. It was also implemented in the form of a compact module in order for mothers to be able to download and store the collected ECG data without having to interrupt or move the logger, and later link the module to a computer for downloading and analyzing the data. A mobile ECG measurement prototype is manufactured and tested to measure the FECG for pregnant women. The experimental results verify a real-time FECG extraction capability for the proposed system. In this paper, we propose an ECG measurement system that shows approximately 91.65% similarity to the MIT database and the conventional algorithm and SNR performance about 10% better.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.226-229
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• 2010

LED(Light Emitting Diode) is an emitting device which energy is same to the bandgap of p-type and n-type semiconductor junction. Recently high brightness LED is used in fish-luring light and traffic signal light alternative of normal light bulb, and widely used in the area of display pannel. Moreover nowadays LED has been used as a back light of LCD display. Recently, visible light communication(VLC) using LED, that allow two-way serial data communication between LEDs over a distance of sveral centimeters or meters, has been widely studied in the area of digital information transmission along with illumination and display. In this paper, we present LED communication system and their applications.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.4
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• pp.315-322
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• 2008

Valves in power plants are leaking internally by various damages including insertion of foreign objects on seat, seat crack, defects and fatigue crack of stem packing or welds etc. due to severe operating conditions such as high temperature and high pressure for extended period time. Acoustic emission(AE) technology should be applied in order to diagnose precisely and evaluate these valve internal leak. In this paper, results of studies which have accomplished in actual power plant are presented. We have analyzed background noise, AE signal level and frequency spectrum through laboratory tests on the basis of various actual conditions in power plant, and also have considered evaluation methods on the background noise, AE properties and the detectable minimum leak rate according to valve leak conditions through comparing with results of field tests in power plant. As a result of these studies, we conformed that evaluation of internal leak conditions including discrimination of leak or not, and the detectable minimum leak rate is possible, and also it is expected to contribute to safe operation and prevention of energy loss in power plants.

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.935-940
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• 2005

Fluorescence change of coumarin labeled phosphate binding protein (PBP-MDCC) was monitored to measure the amount of released inorganic phosphate ($P_{i}$) during nucleoside triphosphate (NTP) hydrolysis reaction. After purification of PBP-MDCC, fluorescence emission spectra showed that fluorescence responded linearly to $P_{i}$ up to about 0.7 molar ratio of $P_{i}$ to protein. The correlation of fluorescence signal and $P_{i}$ standard was measured to obtain [$P_{i}$] - fluorescence intensity standard curve on the stopped-flow instrument. When T7 bacteriophage helicase, double-stranded DNA unwinding enzyme using dTTP hydrolysis as an energy source, reacted with dTTP, the change of fluorescence was able to be converted to the amount of released $P_{i}$ by the $P_{i}$ standard curve. $P_{i}$ release results showed that single-stranded Ml3 DNA stimulated dTTP hydrolysis reaction several folds by T7 helicase. Instead of end point assay in NTP hydrolysis reaction, real time $P_{i}$-release assay by PBP-MDCC was proven to be very easy and convenient to measure released $P_{i}$.

• Journal of Korea Multimedia Society
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• v.5 no.4
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• pp.426-433
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• 2002

In this paper, we have studied the images which have been reconstructed by using combination of images acquired by the variation of operating frequency. When inner images have been reconstructed, they have been superposed by the surface state effect. In this case, the images of the phase object can be enhanced by the contrast of inner images. In this experiment, there are two kinds of specimens, one is a reference block haying 1/4T, 1/2T, 3/4T side drilled holes as main run piping material 111 the steam generator in NPP(Neuclear Power Plant)s and the another is a part of a hemisphere type specimen having about 1-2㎜ distance gap. It has been shown that the two results of defect shapes have better than before in this processing and phase contrast grow about twice. And we have constructed the acoustic microscope by using a quadrature detector that enables to acquire the amplitude and phase of the reflected signal simultaneously Further more ore have studied the reconstruction method of the amplitude and phase images and the enhancement method of the defect images contrast.

• Journal of Radiation Industry
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• v.4 no.3
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• pp.209-213
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• 2010

Bacterial blight is one of the most serious diseases of rice (Oryza sativa L.), and it has been known that Xanthomonas oryzae pv. oryzae (Xoo) causes this disease symptom. To develop resistance rice cultivars against Xoo, 3,000 lines of $M_3$ mutants, which were irradiated with gamma ray, were tested by 'scissor-dip method' primarily, and 191 putative resistant lines were selected. In $M_4$ generation, these lines were screened again with various ways such as measuring of symptom of bacterial blight in leaf, number of tiller, fresh weight, and phenotypic segregation ratio in next generation. Finally, six resistance lines were selected. RT-PCR analysis revealed that these lines displayed high level of R-genes such as Xa21, Pi36, and Pi-ta. These results indicate that mutations by gamma ray cause disruptions of regulatory signal transduction systems of these R-genes. Furthermore, these selected mutants could be useful for the development of rice cultivar resistant to Xoo.

• Steel and Composite Structures
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• v.21 no.6
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• pp.1183-1210
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• 2016

Viscoelastic sandwich structures (VSSs) are widely used in mechanical equipment, but in the service process, they always suffer from aging which affect the whole performance of equipment. Therefore, aging state recognition of VSSs is significant to monitor structural state and ensure the reliability of equipment. However, non-stationary vibration response signals and weak state change characteristics make this task challenging. This paper proposes a novel method for this task based on adaptive second generation wavelet packet transform (ASGWPT) and multiwavelet support vector machine (MWSVM). For obtaining sensitive feature parameters to different structural aging states, the ASGWPT, its wavelet function can adaptively match the frequency spectrum characteristics of inspected vibration response signal, is developed to process the vibration response signals for energy feature extraction. With the aim to improve the classification performance of SVM, based on the kernel method of SVM and multiwavelet theory, multiwavelet kernel functions are constructed, and then MWSVM is developed to classify the different aging states. In order to demonstrate the effectiveness of the proposed method, different aging states of a VSS are created through the hot oxygen accelerated aging of viscoelastic material. The application results show that the proposed method can accurately and automatically recognize the different structural aging states and act as a promising approach to aging state recognition of VSSs. Furthermore, the capability of ASGWPT in processing the vibration response signals for feature extraction is validated by the comparisons with conventional second generation wavelet packet transform, and the performance of MWSVM in classifying the structural aging states is validated by the comparisons with traditional wavelet support vector machine.

• Journal of electromagnetic engineering and science
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• v.19 no.1
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• pp.64-70
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• 2019

In this study, a compact series-fed center-fed open-stub (SFCFOS) linear array antenna for K-band applications is presented. The antenna is composed of a single-line 10-element linear array. A symmetrical Chebyshev amplitude distribution (CAD) is used to obtain a low sidelobe characteristic against a uniform amplitude distribution (UAD). The amplitude is controlled by varying the width of the microstrip patch elements, and open-ended stubs are arranged next to the last antenna element to use the energy of the radiating signal more effectively. We insert a series-fed stub between two patches and obtain a low mutual coupling for a 4.28-mm center-to-center spacing ($0.7{\lambda}$ at 21 GHz). A prototype of the antenna is fabricated and tested. The overall size of the uniform linear array is $7.04{\times}1.05{\times}0.0563{\lambda}_g^3$ and that of the Chebyshev linear array is $9.92{\times}1.48{\times}0.0793{\lambda}_g^3$. The UAD array yields a ${\mid}S_{11}{\mid}$ < -10 dB bandwidth of 1.33% (20.912-21.192 GHz) and 1.45% (20.89-21.196 GHz) for the CAD. The uniform array design gives a -23 dB return loss, and the Chebyshev array achieves a -30.68 dB return loss at the center frequency with gains of 15.3 dBi and 17 dBi, respectively. The simulated and measured results are in good agreement.

• Integrative Medicine Research
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• v.3 no.4
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• pp.204-210
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• 2014

The aim of this review was to understand the effects of ${\beta}$-adrenergic stimulation on oxidative stress, structural remodeling, and functional alterations in the heart and cerebral artery. Diverse stimuli activate the sympathetic nervous system, leading to increased levels of catecholamines. Long-term overstimulation of the ${\beta}$-adrenergic receptor (${\beta}AR$) in response to catecholamines causes cardiovascular diseases, including cardiac hypertrophy, stroke, coronary artery disease, and heartfailure. Although catecholamines have identical sites of action in the heart and cerebral artery, the structural and functional modifications differentially activate intracellular signaling cascades. ${\beta}AR$-stimulation can increase oxidative stress in the heart and cerebral artery, but has also been shown to induce different cytoskeletal and functional modifications by modulating various components of the ${\beta}AR$ signal transduction pathways. Stimulation of ${\beta}AR$ leads to cardiac dysfunction due to an overload of intracellular $Ca^{2+}$ in cardiomyocytes. However, this stimulation induces vascular dysfunction through disruption of actin cytoskeleton in vascular smooth muscle cells. Many studies have shown that excessive concentrations of catecholamines during stressful conditions can produce coronary spasms or arrhythmias by inducing $Ca^{2+}$-handling abnormalities and impairing energy production in mitochondria, In this article, we highlight the different fates caused by excessive oxidative stress and disruptions in the cytoskeletal proteome network in the heart and the cerebral artery in responsed to prolonged ${\beta}AR$-stimulation.