• Fire Science and Engineering
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• v.18 no.2
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• pp.20-26
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• 2004

The purpose of this study is to investigate the transition mechanism and prevention mechanism of gas explosion to fire. Transition phenomena of explosion to fire of LPG in the explosion vessel of its size of TEX>$100 cm {\times} 60 cm {\times} 45 cm$ was visualized using the high speed video camera and the mechanism was analysed from the videograph. Newspaper size of $30cm {\times} 20cm$ was used for combustible sample in this experiments and LPG-air mixture was ignited by 10 ㎸ electric spark. Experimental parameter was gas concentration, size of vent area and position of combustible solid. Size of vent area were varied as $10cm {\times} 9cm, 13cm {\times} 10cm, 27cm {\times} 20cm, 40cm {\times} 27cm$, and the position of combustible was varied in 4 point. Carbon dioxide was used to study the prevention mechanism of explosion to fire transition of LPG. Based on this experiment we can find that transition possibility of explosion to fire on solid combustible from explosion is depends on concentration of LPG-air mixture and the exposure time of solid combustibles in high temperature atmosphere of flame and burnt gas. And cooling or inerting of the atmosphere after explosion can be prevent the transition of explosion to fire on solid combustibles from gas explosion.

• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1685-1695
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• 2021

To generate a deep learning model with high performance, a large training dataset should be required. However, it requires a lot of time and cost to generate a large training dataset in remote sensing. Therefore, the importance of transfer learning of deep learning model using a small dataset have been increased. In this paper, we performed transfer learning of trained model based on open datasets by using orthoimages and digital maps to detect changes of building objects in multitemporal orthoimages. For this, an initial training was performed on open dataset for change detection through the HRNet-v2 model, and transfer learning was performed on dataset by orthoimages and digital maps. To analyze the effect of transfer learning, change detection results of various deep learning models including deep learning model by transfer learning were evaluated at two test sites. In the experiments, results by transfer learning represented best accuracy, compared to those by other deep learning models. Therefore, it was confirmed that the problem of insufficient training dataset could be solved by using transfer learning, and the change detection algorithm could be effectively applied to various remote sensed imagery.

• Proceedings of the Korean Fiber Society Conference
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• 1998.04a
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• pp.306-309
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• 1998

가잠견피브로인 필름은 메탄올과 같은 간단한 용매를 사용하여 결정구조를 전이시킬 수 있는 것으로 알려져 있으며 이러한 성질을 이용하여 효소고정화소재 등으로서 활용이 검토되고 있다. 그러나 작잠견사로 제조한 자잠피브로인에 대한 연구보고는 많지 않으며 특히 메탄을 처리농도 및 처리시간에 따른 결정구조에 대한 체계적인 연구결과는 보고되어 있지 않다.(중략)

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.3
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• pp.270-280
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• 2016

This paper investigates the evolution of EM admittance of piezoelectric transducers mounted on a notched beam from wave propagation perspective. A finite element analysis is adopted to obtain numerical solutions for Lamb waves reverberating on the notched beam. The mode-converted Lamb wave signals due to a notch are extracted by using the polarization characteristics of piezoelectric transducers collocated on the beam. Then, a series of temporal spectrums are computed to demonstrate the evolution of EM admittance through fast Fourier transform of the mode-converted Lamb wave signals which are consecutively truncated in the time domain. When truncation time is relatively small, the corresponding temporal spectrum is governed by the characteristics of the input driving frequency. As truncation time becomes large, however, the modal characteristics of the notched beam play a crucial role in the temporal spectrum within the input driving frequency band. This implies that mode-converted Lamb waves reverberating on the beam contributes to the resonance of the beam. The root mean square values are computed for the temporal spectrums in the vicinity of each resonance frequency. The root mean square values increase monotonically with respect to truncation time for any resonance frequencies. Finally the implications of the numerical observation are discussed in the context of damage detection of a beam.

• The Journal of the Acoustical Society of Korea
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• v.23 no.5
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• pp.420-427
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• 2004

This paper presents real time implementation of 4kbps EHSX (Enhanced Harmonic Stochastic Excitation) speech coder that combines the harmonic vector excitation coding with time-separated transition coding. The harmonic vector excitation coding uses the harmonic excitation coding for voiced frames and used the vector excitation coding with the structure of analysis-by-synthesis for unvoiced frames, respectively. For transition frames mixed with voiced and unvoiced signal, we use the time-separated transition coding. In this paper. we present the optimization methods of implementation speech coder on the EMS320C6701/sup (R)/ DSP. To reduce the complex for real-time implementation. we perform the optimization method in algorithm by replacing the complex sinusoidal synthesis method with IFFT. and we apply fully pipelines hand assembly coding after converting it from floating source to fixed source. To generate a more efficient code. we also make use or the available EMS320C6701/sup (R)/ resources such as Fastest67x library and memory organization.

• Membrane Journal
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• v.24 no.1
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• pp.50-62
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• 2014

An asymmetric microfiltration membranes were prepared with polysulfone by an immersion precipitation phase inversion method. Microfiltration membranes were prepared by polysulfone/N-methyl-2-pyrrolidone/polyvinylpyrrolidone/phosphoric acid casting solution and water coagulant. The vapor induced phase inversion method was used to prepare the membranes. The pore size and the morphology were changed by the phosphoric acid additive, the temperature of casting plate and the exposure time at the relative humidity of 74%. The morphology of membranes was investigated by scanning electron microscopy and microflow permporometer. By the addition of the phosphoric acid additive in the casting solution, the morphology of the prepared membranes were changed from a dense sponge structure to a loose asymmetric sponge structure. Due to the addition of catalytic amount of phosphoric acid to NMP casting solution, the mean pore size increased almost $0.2{\mu}m$ and the water flux increased about 3,000 LMH. The temperature of casting plate and exposure time had a apparent effect on the skin layer structure and the pore size and the porosity of the membrane.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.2
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• pp.69-76
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• 2020

In this paper, we introduce a method to visualize the contrast diffusion patterns and the dynamic vascular patterns in a contrast-enhanced ultrasound image sequence. We present an imaging technique to visualize parameters such as contrast arrival time, peak intensity time, and contrast decay time in contrast-enhanced ultrasound data. The contrast flow pattern and its velocity are important for characterizing focal liver lesions. We propose a method for representing the contrast diffusion patterns as an image. In the methods, respiratory motion may degrade the accuracy of the parametric images. Therefore, we present a respiratory motion tracking technique that uses dynamic weights and a momentum factor with respect to the respiration cycle. Through the experiment using 72 CEUS data sets, we show that the proposed method makes it possible to overcome the limitation of analysis by the naked eye and improves the reliability of the parametric images by compensating for respiratory motion in contrast-enhanced ultrasonography.

• Journal of the Korean Ceramic Society
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• v.36 no.3
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• pp.231-236
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• 1999

냉각속도가 재열처리가 AFD 방법에 의해 제작된 76SiO2-14B2O3-6Na2O-4Al2O3 유리박막의 광학적 특성에 미치는 영향을 조사하였다. 유리박막의 열팽창계수는 30$0^{\circ}C$부터 전이온도 사이에서 약 5$\times$10-6/$^{\circ}C$이었으며, 전이온도는 62$0^{\circ}C$였다. 유리박막을 전이온도 이하에서 열처리할 경우 열처리 시간이 증가함에 따라 굴절률은 증가하였으며, 열처리 온도가 증가함에 따라 굴절률의 증가속도는 더 컸다. 열처리온도에 따른 유리박막의 복굴절(TE-TM)감소는 굴절률이 가장 크게 증가하는 온도인 $600^{\circ}C$에서 가장 효과적이다. 한편, 냉각속도가 증가함에 따라 유리박막의 두께는 증가하였으며, 굴절류른 감소하였다.

• Radiation Oncology Journal
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• v.29 no.2
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• pp.127-133
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• 2011

Five and half years ago, a 45-year-old female metastatic gastric cancer patient underwent a metastatectomy and chemotherapy. Over the last 4 years and 2 months, she received radiotherapy for every new distant metastasis with intermittent TS-1 oral chemotherapy. She received 8 courses of radiotherapy at 17 metastatic sites for more than 4 years. Metastatic sites which received a curative radiation dose achieved and maintained local control. The patient is now 51 years of age and lives without difficulty in performing her daily activities.

• The Korean Journal of Pesticide Science
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• v.2 no.2
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• pp.68-74
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• 1998

벼멸구의 카보후란에 대한 저항성 기작을 구명하기 위해 실내에서 카보후란으로 30세대 도태하여 얻은 저항성계통($LD_{50};\;20.3{\mu}g/g$)과 약제를 12년 동안 처리하지 않은 벼멸구 감수성 계통($LD_{50};\;0.3{\mu}g/g$)을 완충용액과 마쇄하여, 105,000g에서 2시간 원심분리하여 얻은 상등액(에스테라제층)과 침전물(P450-산화효소층)을 효소액으로 하여 $^{14}C$-카보후란을 반응시켜 계통 간 대사물 량의 차이를 조사한 바 저해제(piperonyl butoxide; 산화효소저해제, diethylmalate; 글루타치온 전이효소 저해제, iprobenfos; 에스테라제 저해제)와 보조인자 (NADPH; P-450 산화효소, 글루타치온; 글루타치온전이효소)에 상관없이 카보후란의 대사물과 그 양이 계통간 차이가 없었다. 이상의 결과로부터 저항성 벼멸구에서 일반적으로 곤충에서 생화학적 저항성 기구로 잘 알려진 가수 분해 효소의 일종인 에스테라제와 p-450 산화효소, 글루타치온 전이효소의 활성 증가가 저항성 발달에 관여하지 않음을 알 수 있었다.