• Biomolecules & Therapeutics
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• v.19 no.4
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• pp.487-492
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• 2011

In our previous study, we investigated Chenopodium album Linne (CAL) ethanol extract and its fractions on anti-gastritic actions using the HCl/ethanol and indomethacin induced gastric lesion model and Helicobacter pylori (H. pylori). Based on the results, butanol fraction was most effective among fractions obtained from CAL. This study aims to elucidate the mechanisms of butanol fraction, and betaine as a constituent of the butanol fraction, on gastritis and anti-gastric cancer cell growth. First, we examined antioxidant properties using hydrogen peroxide and superoxide radical, and we found that butanol fraction and betaine may be good antioxidants. Second, cytotoxicity was assessed by measuring cell viability and 4,6-diamidino-2-phenylinodole dihydrochloride (DAPI) staining of human gastric cancer cells (AGS cells). We also examined the relationship between the cytotoxicity and intracellular $Ca^{2+}$ signaling mechanism. The butanol fraction demonstrated cell viability 71.49% at the concentration of 100 ${\mu}g/ml$ and increased intracellular $Ca^{2+}$ concentration in a dose dependent manner. Finally, we observed the mucus content as a defensive factor and gastric secretion as an aggressive factor, and found that the mucus content noticeably increased when treated with butanol fraction and betaine and gastric secretion decreased when treated with betaine in vivo study. From these results, we suggest that CAL butanol fraction and betaine may have protective effects on gastritis.

• Korean Journal of Pharmacognosy
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• v.29 no.1
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• pp.1-7
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• 1998

Aqueous extract of Morus alba L. blocked the toxic effect of paraquat on E. coli growth. The active components in the extract may be capable of crossing the cell membranes and protect against superoxide toxicity in E. coli, The extract inhibited $FeSO_4/H_2O_2$ induced lipid peroxidation in rat liver homogenate and protected against t-butyl hydroperoxide caused Ac2F cell damage. Moreover, the extract showed inhibitory effect on phospholipase $A_2$ activity in a dose dependent manner. Antiinflammatory effect of the extract was further investigated using the carrageenin-induced oedema model. A single adminstration of the extract (3g/kg body, p.o.) was more effective than indomethacin. These results suggest that the isolation and identification of the active components would have significant therapeutic application to inflammation associated with oxygen radicals.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.3
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• pp.181-193
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• 2010

The paper presents an alternative way to classical stereocorrelation. First, 2D image processing of random patterns is described. Sub-pixel displacements are determined using phase analysis. Then distortion evaluation is presented. The distortion is identified without any assumption on the lens model because of the use of a grid technique approach. Last, shape measurement and shape variation is caught by fringe projection. Analysis is based on two pin-hole assumptions for the video-projector and the camera. Then, fringe projection is coupled to in-plane displacement to give rise to 3D measurement set-up. Metrological characterization shows a resolution comparable to classical (stereo) correlation technique ($1/100^{th}$ pixel). Spatial resolution seems to be an advantage of the method, because of the use of temporal phase stepping (shape measurement, 1 pixel) and windowed Fourier transform (in plane displacements measurement, 9 pixels). Two examples are given. First one is the study of skin properties; second one is a study on leather fabric. In both cases, results are convincing, and have been exploited to give mechanical interpretation.

• Structural Engineering and Mechanics
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• v.76 no.4
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• pp.435-449
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• 2020

This work presents the formulation of the isogeometric collocation method to solve the strong form equation of a unified and integrated approach of Reissner Mindlin plate theory (UI-RM). In this plate theory model, the total displacement is expressed in terms of bending and shear displacements. Rotations, curvatures, and shear strains are represented as the first, the second, and the third derivatives of the bending displacement, respectively. The proposed formulation is free from shear locking in the Kirchhoff limit and is equally applicable to thin and thick plates. The displacement field is approximated using the B-splines functions, and the strong form equation of the fourth-order is solved using the collocation approach. The convergence properties and accuracy are demonstrated with square plate problems of thin and thick plates with different boundary conditions. Two approaches are used for convergence tests, e.g., increasing the polynomial degree (NELT = 1×1 with p = 4, 5, 6, 7) and increasing the number of element (NELT = 1×1, 2×2, 3×3, 4×4 with p = 4) with the number of control variable (NCV) is used as a comparable equivalent variable. Compared with DKMQ element of a 64×64 mesh as the reference for all L/h, the problem analysis with isogeometric collocation on UI-RM plate theory exhibits satisfying results.

• Smart Structures and Systems
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• v.24 no.6
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• pp.733-744
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• 2019

Wind speed forecasting is critical for a variety of engineering tasks, such as wind energy harvesting, scheduling of a wind power system, and dynamic control of structures (e.g., wind turbine, bridge, and building). Wind speed, which has characteristics of random, nonlinear and uncertainty, is difficult to forecast. Nowadays, machine learning approaches (generalized regression neural network (GRNN), back propagation neural network (BPNN), and extreme learning machine (ELM)) are widely used for wind speed forecasting. In this study, two schemes are proposed to improve the forecasting performance of machine learning approaches. One is that optimization algorithms, i.e., cross validation (CV), genetic algorithm (GA), and particle swarm optimization (PSO), are used to automatically find the optimal model parameters. The other is that the combination of different machine learning methods is proposed by finite mixture (FM) method. Specifically, CV-GRNN, GA-BPNN, PSO-ELM belong to optimization algorithm-assisted machine learning approaches, and FM is a hybrid machine learning approach consisting of GRNN, BPNN, and ELM. The effectiveness of these machine learning methods in wind speed forecasting are fully investigated by one-year field monitoring data, and their performance is comprehensively compared.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2016.09a
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• pp.41-43
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• 2016

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.8
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• pp.3821-3841
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• 2019

Cloud radio access networks (C-RANs) have been regarded in recent times as a promising concept in future 5G technologies where all DSP processors are moved into a central base band unit (BBU) pool in the cloud, and distributed remote radio heads (RRHs) compress and forward received radio signals from mobile users to the BBUs through radio links. In such dynamic environment, automatic decision-making approaches, such as artificial intelligence based deep reinforcement learning (DRL), become imperative in designing new solutions. In this paper, we propose a generic framework of autonomous cell activation and customized physical resource allocation schemes for energy consumption and QoS optimization in wireless networks. We formulate the problem as fractional power control with bandwidth adaptation and full power control and bandwidth allocation models and set up a Q-learning model to satisfy the QoS requirements of users and to achieve low energy consumption with the minimum number of active RRHs under varying traffic demand and network densities. Extensive simulations are conducted to show the effectiveness of our proposed solution compared to existing schemes.

• Advances in nano research
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• v.11 no.6
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• pp.667-678
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• 2021

Multiwalled carbon nanotubes (MWCNTs) were first oxidized (O-CNTs) to introduce carboxylic group and then further functionalized (F-CNTs) with m-phenylenediamine, which was confirmed by FTIR and SEM. It was used as an effective adsorbent for the adsorptive removal of diclofenac drug from water. Under optimum conditions of pH 6, stirring speed 600 rpm, the maximum adsorption capacity obtained was 532 mg g^-1 which is superior to the values reported in literature. The adsorption was quite rapid as 25 mg L^-1 drug solution was adsorbed in only 3 minutes of contact time with 10 mg of adsorbent dose. The adsorption kinetics and isotherms were studied using various models to evaluate the adsorption process. The results showed that the data best fit in kinetics pseudo-second order and Langmuir isotherm model. Furthermore, the oxidized and functionalized MWCNTs were applied on gram-negative Escherichia coli and gram-positive Staphylococcus aureus using agar disc diffusion assay to validate their anti-microbial activity. Results were unique as both oxidized and functionalized MWCNTs were equally active against both E. coli and S. aureus. The newly synthesized F-CNTs have great potential in water treatment, with their dual action of removing drug and pathogens from water, makes it potential applicant to save environment.

• Transactions of Materials Processing
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• v.32 no.2
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• pp.92-99
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• 2023

In this study, shear fracture specimens are designed using finite element analyses for the characterization of ductile fracture criteria of metal sheets. Many recently suggested ductile fracture criteria require experimental fracture data at the shear stress states in the model parameter identification. However, it is challenging to maintain shear stress states in tension-based specimens from the initial yield to the final fracture, and the loading path can be different for the different materials even with the same shear specimen geometries. To account for this issue, two different shear fracture specimens for low ductility/high ductility metal sheets are designed using the sensitivity tests conducted by finite element simulations. Priorly mechanical properties including the Hosford-Coulomb fracture criterion of the aluminum alloy 7075-T6 and DP590 steel sheets are used in the simulations. The results show that shear stress states are well-maintained until the fracture at the fracture initiation points by optimizing the notch geometries of the shear fracture specimens.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.637-640
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• 2023

This paper presents multimodal image fusion with human pose for detecting abnormal human behaviors in low illumination conditions. Detecting human behaviors in low illumination conditions is challenging due to its limited visibility of the objects of interest in the scene. Multimodal image fusion simultaneously combines visual information in the visible spectrum and thermal radiation information in the long-wave infrared spectrum. We propose an abnormal event detection scheme based on the multimodal fused image and the human poses using the keypoints to characterize the action of the human body. Our method assumes that human behaviors are well correlated to body keypoints such as shoulders, elbows, wrists, hips. In detail, we extracted the human keypoint coordinates from human targets in multimodal fused videos. The coordinate values are used as inputs to train a multilayer perceptron network to classify human behaviors as normal or abnormal. Our experiment demonstrates a significant result on multimodal imaging dataset. The proposed model can capture the complex distribution pattern for both normal and abnormal behaviors.