• Transactions of Materials Processing
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• v.25 no.1
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• pp.36-42
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• 2016

Fiber metal laminates (FMLs) are well known for improved fatigue strength, better impact resistance, superior damage tolerance and slow crack growth rate compared to traditional metallic materials. However, defects and loss of strength of a composite material can occur due to the vertical load from the punch during the joining with a dissimilar material using a conventional clinching method. In the current study, tapered-hole clinching was an alternative process used to join Al 5052 and FMLs. The tapered hole was formed in the FML before the joining. For the better understanding of static and dynamic characteristics, a clinched joining followed by a tensile-shear test was numerically simulated using the finite element analysis. The design parameters were also evaluated for the geometry of the tapered hole by the Taguchi method in order to improve and compare the lateral joining strength of the clinched joint. The influence of the neck thickness and the undercut were evaluated and the contribution of each design parameter was determined. Then, actual experiments for the joining and tensile-shear test were conducted to verify the results of the numerical simulations. In conclusion, the appropriate combination of the design parameters can improve the joining strength and the cross-sections of the tapered-hole clinched joint formed in the actual experiments were in good agreement with the results of the numerical simulations.

• International Journal of Fluid Machinery and Systems
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• v.5 no.3
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• pp.134-142
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• 2012

The competition to deliver ultra-low emitting vehicles at a reasonable cost is driving the automotive industry to invest significant manpower and test laboratory resources in the design optimization of increasingly complex exhaust after-treatment systems. Optimization can no longer be based on traditional approaches, which are intensive in hardware use and laboratory testing. The CFD is in high demand for the analysis and design in order to reduce developing cost and time consuming in experiments. This paper describes the development of a comprehensive practical model based on experiments for simulating the performance of automotive three-way catalytic converters, which are employed to reduce engine exhaust emissions. An experiment is conducted to measure species concentrations before and after catalytic converter for different loads on engine. The model simulates the emission system behavior by using an exhaust system heat conservation and catalyst chemical kinetic sub-model. CFD simulation is used to study the performance of automotive catalytic converter. The substrate is modeled as a porous media in FLUENT and the standard k-e model is used for turbulence. The flow pattern is changed from axial to radial by changing the substrate model inside the catalytic converter and the flow distribution and the conversion efficiency of CO, HC and NOx are achieved first, and the predictions are in good agreement with the experimental measurements. It is found that the conversion from axial to radial flow makes the catalytic converter more efficient. These studies help to understand better the performance of the catalytic converter in order to optimize the converter design.

• Journal of the Korea Society of Computer and Information
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• v.24 no.12
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• pp.1-7
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• 2019

With the in-depth development of machine learning, the deep learning method has made great progress, especially with the Convolution Neural Network(CNN). Compared with traditional text sentiment classification methods, deep learning based CNNs have made great progress in text classification and processing of complex multi-label and multi-classification experiments. However, there are also problems with the neural network for text sentiment classification. In this paper, we propose a fusion model based on Long-Short Term Memory networks(LSTM) and CNN deep learning methods, and applied to multi-category news datasets, and achieved good results. Experiments show that the fusion model based on deep learning has greatly improved the precision and accuracy of text sentiment classification. This method will become an important way to optimize the model and improve the performance of the model.

• Archives of Pharmacal Research
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• v.26 no.11
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• pp.917-924
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• 2003

This research aims to test a new drug candidate based on a traditional medicinal herb, F1, an herbal extract obtained from Astragalus membranaceus and its main ingredient, 1-monolinolein that may have fewer side effects and less uterine hypertrophy. In vitro experiments, human osteoblast-like cell lines, MG-63 and Saos-2, were analyzed by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) and an alkaline phosphatase (ALP) assays. Mouse osteoclasts were induced through a calcium-deficient diet and inhibition effects were measured. In vivo experiments were done using ovariectomized (OVX) rats for 9 weeks. At necropsy, uterus weights were measured, trabecular bone area (TBA) of tibia and lumbar vertebra were measured bone histomorphology. In results, cell proliferation and ALP activity in Saos-2 by ether F1 or 1-monolinolein did not increased significantly compared to the control. The F1 inhibited osteoclast development ($IC_{25}=3.37{\times}10^{-5}$mg/mL) less than 17$\beta$-estradiol. The OVX rats administered F1 (2 mg/kg/day and 10 mg/kg/day) showed an increase in TBA of the tibia significantly (136.3${\pm}4.2% and 138.5{\pm}$10.3% of control). In conclusions, the herbal extract, F1 inhibited tibia and lumbar bone loss and did not cause uterine hypertrophy. However, 1-monolinolein, the main ingredient of the herbal extract, did not inhibit bone loss.

• BMB Reports
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• v.41 no.5
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• pp.369-375
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• 2008

Polygonatum cyrtonema Lectin (PCL), which is classified as a monocot mannose-binding lectin, has received great regards for its uniquely biological activities and potentially medical applications in cancer cells. This paper was initially aimed to study apoptosis of PCL on Hela cells. Thus, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) method was carried out. Through observation of cell morphologic changes and Lactate dehydrogenase (LDH) activity-based cytotoxicity assays, PCL induced HeLa cell apoptosis in a dose-dependent manner. To further gain structural basis, multiple alignments, homology modeling and docking experiments were performed to analyze the correlation between its biological activities and mannose-binding sites. Eventually, considering docking data, chemical modification properties on the three mannose-binding sites were analyzed by a series of biological experiments (e.g., hemagglutinating and mitogenic activity assays, fluorescence and Circular Dichrosim (CD) spectroscopy) to profoundly identify the role of some key amino acids in the structure-function relationship of PCL.

• Journal of Korea Spatial Information System Society
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• v.11 no.4
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• pp.56-64
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• 2009

As the Internet has been improved to Web 2.0, it introduces new approaches including Rich Internet Application (RIA) technology such as Flash, AJAX, Silverlight, etc. The RIA which is platform independent technology allows applications to provide rich client-side interfaces, and allows the browser to interact with users without communication to server. In this paper, we propose a method of spatial data service based on RIA technology. Internet map service using spatial data generally requires rich client-side interfaces and various interactions. These features can be provided by the RIA. The proposed method uses Flash developed by Macromedia as RIA technology. It can be applicable on any platform including mobile environment. The spatial data server makes Flash file known as SWF (Shock Wave File) with manipulation code for map and spatial data that is requested by user, and send it to the web browser. Once the web browser receives a SWF, client SWF manipulates user interactions, such as zooming and panning, without communication with server. Experiments that execute the application on various web browsers including mobile web browser and measure time of map interaction are carried out to compare with traditional bitmap based WMS (Web Map Service). As a result of experiments, we have confirmed improvement of interactivity and performance with RIA approach.

• Journal of Korean Medicine Rehabilitation
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• v.18 no.2
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• pp.157-167
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• 2008

Objectives : It is sure that standardization of medical instruments is very important and necessary. Cupping therapy is one of the traditional oriental medical method, and it is necessary to set up a standard of cupping therapy and instruments. Methods : We select 3 major cupping instrument makers according to a questionnaire survey of 2001 oriental medical doctors. Dae Gun is A maker, Han Sol is B maker, Dong Bang is C maker. And with these air pumps we make experiments on stability by an inner impact test and a falling test. With these cups we check stability by an inner impact test and a disinfection test. And to know function of these instruments we test a negative pressure and maintain attached cups until 5 to 10minutes. Results : All results of experiments(impacted test, disinfection test, falling test) on stability of cups and air pumps are suitable for medical instrument. And the efficiency of 3 major makers shows various results. Negative pressure of B group is the highest, C group is the second, A group is the lowest. Pressure maintenance test shows A and C group is comparatively up to the experimental standard(<10%), B group is comparatively below the experimental standard(<10%). Conclusions : Results show stability of cups and air pumps is suitable for medical instruments. And negative pressure of cupping and maintenance of pressure show various results. So it is necessary to set up a standard negative pressure of cupping and maintenance of pressure.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.468-475
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• 2018

In medical ultrasound imaging, frequency-dependent attenuation downshifts and reduces a center frequency and a frequency bandwidth of received echo signals, respectively. This causes considerable errors in quadrature demodulation (QDM), result in lowering signal-to-noise ratio (SNR) and contrast resolution (CR). To address this problem, adaptive dynamic QDM (ADQDM) that estimates center frequencies along depth was introduced. However, the ADQDM often fails when imaging regions contain hypoechoic regions. In this paper, we introduce a valid region-based ADQDM (VR-ADQDM) method to reject the misestimated center frequencies to further improve SNR and CR. The valid regions are regions where the center frequency decreases monotonically along depth. In addition, as a low-pass filter of QDM, Gaussian wavelet based dynamic filtering was adopted. From the phantom experiments, average SNR improvements of the ADQDM and the VR-ADQDM over the traditional QDM were 1.22 and 5.27 dB, respectively, and the corresponding maximum SNR improvements were 2.56 and 10.58 dB. The contrast resolution of the VR-ADQDM was also improved by 0.68 compared to that of the ADQDM. Similar results were obtained from in vivo experiments. These results indicate that the proposed method would offer promises for imaging technically-difficult patients due to its capability in improving SNR and CR.

• Korean Journal of Remote Sensing
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• v.26 no.1
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• pp.29-38
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• 2010

It is necessary to develop an integration model which can account for various data acquired at different measurement scales in environmental thematic mapping with high-resolution ground survey data and relatively low-resolution remote sensing data. This paper presents and applies a multi-scale geostatistical methodology for downscaling of thematic maps generated from lowresolution remote sensing data. This methodology extends a traditional ordinary kriging system to a block kriging system which can account for both ground data and remote sensing data which can be regarded as point and block data, respectively. In addition, stochastic simulation based on block kriging is also applied to describe spatial uncertainty attached to the downscaling. Two downscaling experiments including SRTM DEM and MODIS Leaf Area Index (LAI) products were carried out to illustrate the applicability of the geostatistical methodology. Through the experiments, multi-scale geostatistics based on block kriging successfully generated relatively high-resolution thematic maps with reliable accuracy. Especially, it is expected that multiple realizations generated from simulation would be effectively used as input data for investigating the effects of uncertain input data on GIS model outputs.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.1
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• pp.19-28
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• 2021

Recently, in the field of education, various attempts have been made to apply virtual reality technology to an educational field and use it as an educational medium. Accordingly, in the science subject area, it is necessary to simulate science experiments that can make various and active experiments out of various limitations such as space and situation by using virtual reality environment construction technology. In this study, after selecting a physics course from a science subject, an experimental simulation using a parabolic motion formula, one of physical phenomena, is implemented in a virtual space, and then used in actual physics education based on the learning standards of the STEAM theory. Prove this is possible. Through this, it was confirmed that a specific educational model using virtual reality space can be designed, and it shows that education can be conducted with more effective educational methods in various subjects of education through the combination of traditional educational model and modern technology. Regarding the results of the research, it suggests the possibility of future research plans and practical use in the educational field.