• Transactions of the Korean hydrogen and new energy society
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• v.27 no.5
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• pp.571-580
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• 2016

In this paper, performance of the gas turbine combined cycle(GTCC) using pre-combustion carbon capture technology was comparatively analysed. Steam reforming and autothermal reforming were used. In the latter, two different methods were adopted to supply oxygen for the reforming process. One is to extract air form gas turbine compressor (air blowing) and the other is to supply oxygen directly from air separation unit ($O_2$ blowing). To separate $CO_2$ from the reformed gas, the chemical absorption system using MEA solution was used. The net cycle efficiency of the system adopting $O_2$ blown autothermal reforming was higher than the other two systems. The system using air blown autothermal reforming exhibited the largest net cycle power output. In addition to the performance analysis, the influence of fuel reforming and carbon capture on the operating condition of the gas turbine and the necessity of turbine re-design were investigated.

• Clinical and Experimental Reproductive Medicine
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• v.46 no.1
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• pp.8-13
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• 2019

Objective: Density gradient centrifugation (DGC) is frequently used to isolate high-motility fractions of spermatozoa. We compared the efficacy of four DGC media in terms of the percentage of morphologically normal spermatozoa, DNA fragmentation level, and hyaluronic acid (HA) binding ability. Methods: Thirty men with a total motile spermatozoa count > 80 million participated. Semen samples were divided into four aliquots, which were processed using PureSperm, PureCeption, Sidney, and SpermGrad media, respectively. The DNA fragmentation level was measured using the Halosperm assay kit and HA binding ability was measured using the HBA assay kit. Results: The mean percentage of morphologically normal spermatozoa was significantly enhanced after DGC using all four media (10.3%, 9.9%, 9.8%, and 10.7%, respectively; p< 0.05 for each when compared with 6.9% in raw semen). The DNA fragmentation level was significantly reduced after DGC using PureSperm, PureCeption, and SpermGrad media (6.0%, 6.5%, and 4.9%, respectively; p< 0.05 for each when compared with 11.2% in raw semen), but not after DGC using Sidney media (8.5%, p> 0.05). HA binding ability did not change after DGC using any of the four media. Conclusion: The four media were equally effective for obtaining a sperm fraction with highly motile, morphologically normal sperm. PureSperm, PureCeption, and SpermGrad media were equally effective for acquiring a sperm fraction with less DNA fragmentation.

• Membrane Journal
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• v.31 no.4
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• pp.275-281
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• 2021

To evaluate the possibility as a separator in alkaline water electrolysis, the thermal stability, ion conductivity and durability of 5 commercially available anion exchange membranes were tested. The thermal stability of FAAM-PK-75 and FAAM-40 membrane analyzed by thermo-gravimetric analysis (TGA) showed good performance compared to the other three types of AEM, AHO, and AHA membrane. The ion conductivity of AEM membrane measured in 7 M KOH solution at 25℃ and 80℃ had a higher value of about 4~17 times compared to the other membranes. The durability of FAAM-PK-75 tested in 7 M KOH solution at 25℃ was high compared to the other membranes.

• IEMEK Journal of Embedded Systems and Applications
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• v.16 no.4
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• pp.145-151
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• 2021

In this paper, we propose a novel visualization technique to explain the predictions of deep neural networks. We use knowledge distillation (KD) to identify the interior of a black-box model for which we know only inputs and outputs. The information of the black box model will be transferred to a white box model that we aim to create through the KD. The white box model will learn the representation of the black-box model. Second, the white-box model generates attention maps for each of its layers using Grad-CAM. Then we combine the attention maps of different layers using the pixel-wise summation to generate a final saliency map that contains information from all layers of the model. The experiments show that the proposed technique found important layers and explained which part of the input is important. Saliency maps generated by the proposed technique performed better than those of Grad-CAM in deletion game.

• Wind and Structures
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• v.34 no.6
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• pp.511-523
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• 2022

Detecting the icing on wind turbine blades built-in cold regions with conventional methods is always a very laborious, expensive and very difficult task. Regarding this issue, the use of smart systems has recently come to the agenda. It is quite possible to eliminate this issue by using the deep learning method, which is one of these methods. In this study, an application has been implemented that can detect icing on wind turbine blades images with visualization techniques based on deep learning using images. Pre-trained models of Resnet-50, VGG-16, VGG-19 and Inception-V3, which are well-known deep learning approaches, are used to classify objects automatically. Grad-CAM, Grad-CAM++, and Score-CAM visualization techniques were considered depending on the deep learning methods used to predict the location of icing regions on the wind turbine blades accurately. It was clearly shown that the best visualization technique for localization is Score-CAM. Finally, visualization performance analyses in various cases which are close-up and remote photos of a wind turbine, density of icing and light were carried out using Score-CAM for Resnet-50. As a result, it is understood that these methods can detect icing occurring on the wind turbine with acceptable high accuracy.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.510-512
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• 2023

In order to enhance a model's capability for detecting facial expressions, this research suggests a pipeline that makes use of the GradCAM component. The patching module and the pseudo-labeling module make up the pipeline. The patching component takes the original face image and divides it into four equal parts. These parts are then each input into a 2Dconvolutional layer to produce a feature vector. Each picture segment is assigned a weight token using GradCAM in the pseudo-labeling module, and this token is then merged with the feature vector using principal component analysis. A convolutional neural network based on transfer learning technique is then utilized to extract the deep features. This technique applied on a public dataset MMI and achieved a validation accuracy of 96.06% which is showing the effectiveness of our method.

• The Journal of Korean Medicine
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• v.30 no.4
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• pp.13-27
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• 2009

Objectives: Trans-cinnamaldehyde (TCA) is the main component of Cinnamomi Ramulus and it has been reported that TCA inhibits inflammatory responses in various cell types. Inflammation-mediated neurological disorders induce the activation of macrophages such as microglia in brain, and these activated macrophages release various inflammation-related molecules, which can be neurotoxic if overproduced. In this study, we evaluated gene expression profiles using gene chip microarrays in lipopolysaccharide (LPS)-stimulated BV-2 cells to investigate the antiinflammatory effect of TCA on inflammatory responses in brain microglia. Methods: A negative control group was cultured in normal medium and a positive control group was stimulated with $1{\mu}g/ml$ in the absence of TCA. TCA group was pretreated with $10{\mu}g/ml$ before $1{\mu}g/ml$ LPS stimulation. The oligonucleotide microarray analysis was performed to obtain the expression profiles of 28,853 genes using gene chip mouse gene 1.0 ST array in this study. Results: In positive control group, 1522 probe sets were up-regulated in the condition of the cutoff value of 1.5-fold change and 341 genes with Unigene ID were retrieved. In TCA group, 590 probe sets were down-regulated from among 1522 probe sets and 33 genes with Unigene ID were retrieved, which included 6 inflammation-related genes. We found out that Id3 gene is associated with transforming growth factor-${\beta}$ (TGF-${\beta}$) signaling pathway and Klra8 gene is related to natural killer cell-mediated cytotoxicity pathway. Conclusions: The results mean that TCA inhibits inflammatory responses through down-regulating the expressions of inflammation-related genes in LPS-stimulated BV-2 cells.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.2
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• pp.139-144
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• 2008

The focus of this research is that the scavenging aspect of in-cylinder is visualized by the PIV method and its characteristic is analyzed so that the scavenging performance of the free piston hydrogen fueled engine can improve with loop scavenging. As the results, the piston of convex type shows the best scavenging performance among the presented pistons. In case of the abnormal expansion, the scavenging of area between cylinder head and cylinder wall doesn't operate well.

• Proceedings of the KIEE Conference
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• 2001.11a
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• pp.87-89
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• 2001

The structure of manufactured device is Cr-Au/Arachidic acid/Al, the number of accumulated layers are 13, 17 and 19. The I-V characteristic of the device is measured from -2[V] to +2[V] and the characteristic of current-time of the devices. We have investigated the capacitance because this fatty acid system have a accumulated layers. The maximum value of measured current is increased as the number of accumulated layers are decreased. The capacitor properties of a thin film is better as the distance between electrodes is smaller. The results have shown the insulating materials and could control the conductivity by accumulated layers.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.3
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• pp.240-246
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• 2014

In order to develop a universal cryogenic piston pump of small size for increasing utilization of liquid hydrogen, dynamic compression performance of piston pump were evaluated and improvements were also discussed for piston rod and piston tip. The cryogenic piston pump has crosshead structure and inclined cup shape piston tip. As the results, it was found that i) insulation of heat flow from piston-rod part is required for stable operation ii) improving the self-clearance adjustment effect of piston tip and reducing piston eccentricity were desirable to promote pumping pressure and operating range.