• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.8 s.227
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• pp.1075-1086
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• 2004

In this paper, Time Delay Control(TDC) for robot manipulators is analyzed and its problems are founded. In order to remedy the problems, the enhanced controller is proposed and analyzed. The effect of friction associated with TDC is reported and its cause is presented. Through the analysis, simulation and experiment, it is shown that the friction effect causes serious degradation in control performance and that it is a result of the error of Time Delay Estimation(TDE) in TDC. In order to remedy the problems, TDC combined with Internal Model Control(IMC) concept is proposed. The proposed compensator is effective enough to handle the bad effect of friction, and is so simple and efficient as to match positive attribute of TDC. The simulation and experimental results show the effectiveness of proposed controller against the friction of the robot manipulators.

• Tuberculosis and Respiratory Diseases
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• v.54 no.5
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• pp.551-562
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• 2003

Background : NF-${\kappa}B$ is a characteristic transcriptional factor which has been shown to regulate production of acute inflammatory mediators and to be involved in the pathogenesis of many inflammatory lung diseases. There has been some evidence that PI3K/Akt pathway could activate NF-${\kappa}B$ in human cell lines. However, the effect of PI3K/Akt pathway on the activation of NF-${\kappa}B$ varied depending on the cell lines used in the experiments. In this study we evaluated the effect of PI3K/Akt pathway on the activation of NF-${\kappa}B$ in human respiratory epithelial cell lines. Methods : BEAS-2B, A549 and NCI-H157 cell lines were used in this experiment. To evaluate the activation of Akt activation and I${\kappa}B$ degradation, cells were analysed by western blot assay using phospho-specific Akt Ab and $I{\kappa}B$ Ab. To block PI3K/Akt pathway, cells were pretreated with wortmannin or LY294002 and transfected with dominant negative Akt (DN-Akt). For IKK activity, immune complex kinase assay was performed. To evaluate the DNA binding affinity and transcriptional activity of NF-${\kappa}B$, electrophoretic mobility shift assay (EMSA) and luciferase assay were performed, respectively. Results : In BEAS-2B, A549 and NCI-H157 cell lines, Akt was activated by TNF-$\alpha$ and insulin. Activation of Akt by insulin did not induce $I{\kappa}B{\alpha}$ degradation. Blocking of PI3K/Akt pathway via wortmannin/LY294002 or DN-Akt did not inhibit TNF-$\alpha$-induced $I{\kappa}B{\alpha}$ degradation or IKK activation. Inhibition of PI3K/Akt did not affect TNF-$\alpha$-induced NF-${\kappa}B$ activation. Overexpression of DN-Akt did not block TNF-$\alpha$-induced transcriptional activation of NF-${\kappa}B$, but wortmannin enhanced TNF-$\alpha$-induced in NF-${\kappa}B$ transcriptional activity. Conclusion : PI3K/Akt was not involved in TNF-$\alpha$-induced $I{\kappa}B{\alpha}$ degradation or transcriptional activity of NF-${\kappa}B$ in human respiratory epithelial cell lines.

• Tuberculosis and Respiratory Diseases
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• v.40 no.4
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• pp.416-423
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• 1993

Pulmonary alveolar proteinosis(PAP) is thought to be a rare disease of unknown etiology characterized by the accumulation of strong PAS-positive lipoproteinaceous material in the pulmonary alveolar spaces. The defect in the clearance and degradation of intra-alveolar phospholipoproteinaceous material in PAP likely represents dysfunction of type II pneumocytes. Although the causative treatment of PAP is not well known, yet whole lung bronchopulmonary lavage is a relatively safe and effective treatment. We experienced three cases of PAP, which were confirmed by light and electron microscopic examinations of lung tissues obtained by open lung biopsy, transbronchial lung biopsy and lung lavage, so we present 3 cases of PAP with a review of the literature.

• The Korea Journal of Herbology
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• v.21 no.3
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• pp.103-109
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• 2006

Objectives : The purpose of this study was to investigate the TLR-4 mediated anti-inflammatory effects of extract from Xanthii Fructus(XF) on the peritoneal macrophage. Methods : To evaluate of TLR-4 mediated inflammatory of XF, we examined NO and cytokine production in TRL-4 ligand(LPS-lipopolysacchride) induced macrophages. Furthermore, we checked molecular mechanism using western blot. Results : l.Extract from XF reduced LPS-induced Nitric oxide (NO), tumor necrosis factor-a (TNF-a), interleukin (IL)-6 and IL-12 production in peritoneal macrophages 2.Extract from XF itself does not have any cytotoxic effect.XS inhibited degradation of IkBa in the TLR-4 mediated peritoneal macrophages Conclusion : XF down-regulated TLR4 ligand(LPS)-induced NO and cytokine productions.

• The Journal of Internal Korean Medicine
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• v.31 no.2
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• pp.224-241
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• 2010

Objectives : The aim of the current study was to investigate the effects of Sargassum (Sargassum pallidum (TURN.) C. AG.; SP) on the experimental colitis induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) in mice. Methods : ICR mice were divided into 7 groups (NOR, CON, $SS50\times5$, $SP20\times3$, $SP50\times3$, $SP20\times5$, $SP50\times5$). TNBS processing was intrarectally applied to all experimental groups on the 3rd experiment day, except the normal group (NOR). For investigating the prophylactic effect, SP at doses of 20 mg/kg ($SP20\times5$) and 50 mg/kg ($SP50\times5$) were orally administered for 5 days. The SP at doses of 20 mg/kg ($SP20\times3$) and 50 mg/kg ($SP50\times3$) were orally administered for 3 days after the colitis induction in order to check the effect of treatment. As a positive control group, sulfasalazine 50 mg/kg ($SS50\times5$) was administrated. Macroscopic findings of epithelial tissue on mice were measured by colon length and macroscopic score. Histologic findings were also checked by crypt cell, epithelial cell, inflammatory cell and edema of submucosa. We measured the ability of SP to inhibit lipid peroxidation and myeloperoxidase activity. We also measured levels of the inflammatory markers, interleukin (IL)-$1\beta$ and cyclooxygenase-2 (COX-2), its transcription factor activation, phospho-NF-${\kappa}B$ (pp65), in the colon by enzyme-linked immunosorbent assay and immunoblot analysis. We measured activation of fecal bacterial enzyme, $\beta$-glucuronidase and degradation activation of fecal glycosaminoglycan (GAG), and hyaluronic acid. Results : Oral administration of SP on mice inhibited TNBS-induced colon shortening and myeloperoxidase activity in the colon of mice as well as IL-$1\beta$ and COX-2 expression. SP also inhibited TNBS-induced lipid peroxidation and pp65 activation in the colon of mice. SP inhibited $\beta$-glucuronidase activation and fecal hyaluronic acid degradation activation as well. Conclusions : SP could be a possible herbal candidate and preventive prebiotic agent for treating inflammatory bowel disease (IBD). Further experiments to differentiate effects of SP on IBD, such as other solutions and extracting times, might be promising.

• Earthquakes and Structures
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• v.22 no.5
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• pp.461-473
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• 2022

Energy-saving block and invisible multiribbed frame composite wall (EBIMFCW) is an important shear wall, which is composed of energy-saving blocks, steel bars and concrete. This paper conducted seismic performance tests on six 1/2-scale EBIMFCW specimens, analyzed their failure process under horizontal reciprocating load, and studied the effect of axial compression ratio on the wall's hysteresis curve and skeleton curve, ductility, energy dissipation capacity, stiffness degradation, bearing capacity degradation. A formula for calculating the peak bearing capacity of such walls was proposed. Results showed that the EBIMFCW had experienced a long time deformation from cracking to failure and exhibited signs of failure. The three seismic fortification lines of the energy-saving block, internal multiribbed frame, and outer multiribbed frame sequentially played important roles. With the increase in axial compression ratio, the peak bearing capacity and ductility of the wall increased, whereas the initial stiffness decreased. The change in axial compression ratio had a small effect on the energy dissipation capacity of the wall. In the early stage of loading, the influence of axial compression ratio on wall stiffness and strength degradation was unremarkable. In the later stage of loading, the stiffness and strength degradation of walls with high axial compression ratio were low. The displacement ductility coefficients of the wall under vertical pressure were more than 3.0 indicating that this wall type has good deformation ability. The limit values of elastic displacement angle under weak earthquake and elastic-plastic displacement angle under strong earthquake of the EBIMFCW were1/800 and 1/80, respectively.

• Journal of IKEEE
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• v.27 no.4
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• pp.477-485
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• 2023

In this paper, the effect of AC ripple on the lifetime of lithium-ion batteries is experimentally analyzed. Bidirectional power conversion system(PCS) is used to increase the efficiency of energy storage systems (ESS). When connected to the grid, a current ripple with a frequency twice the grid frequency is applied to the battery due to its structure. Therefore, to analyze the effect of AC ripple on Li-ion battery aging, cycle life test are performed by applying charge/discharge profiles of DC current and DC+AC current ripple specifications. Based on the experimental results, direct current internal resistance (DCIR), incremental capacitance (IC), and surface temperature were analyzed. As a result, it is confirmed that AC ripple does not directly affect degradation and that battery degradation slows down after a certain cycle. These results can serve as a guideline for optimizing filters to reduce ripple on the battery side in applications where AC ripple occurs.

• Selected Papers of The Society of Naval Architects of Korea
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• v.2 no.1
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• pp.106-128
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• 1994

An elasto-plastic-damage constitutive model for ductile materials is proposed within the framework of a thermodynamic approach of continuum damage mechanics (CDM) in which internal irreversible thermodynamic changes of micro-structure of materials such as plastic deformation and damage evolution are considered as thermodynamic state variables. The new constitutive model can predict not only the elasto-plastic behaviors but also the sequential stiffness degradation process of ductile materials more rationally.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.2
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• pp.180-185
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• 2014

DC motor is a representative electric motor commonly utilized in various motion control fields. However, DC motor-based motion control systems suffer from degradation of position precision due to nonlinear static friction. In order to enhance control precision, friction model-based compensators have been introduced in previous researches, where friction models are identified and counter inputs are added to control inputs for cancelling out the identified friction forces. In this paper, a static friction compensator is proposed without use of a friction model. The proposed compensation algorithm utilizes internal state manipulation to generate compensation pulses, and related parameters are easily tuned experimentally. The proposed friction compensator is applied to a DC motor-based motion control system, and results are presented in comparison with those without a friction compensator.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.228-228
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• 2009

In stator windings of a 6.6kV rotating machine, internal discharge, corona discharge, and surface discharge are mainly caused by internal voids and insulation degradation. In the case of the discharge spark and electromagnetic pulse generated from a discharge source, we can detect it using various RF resonators like an EM sensor. In order to detect these types of electromagnetic sources, we designed and fabricated a planar patch sensor using a CST-MWS simulation, and PD signals from artificial defected stator windings were also measured by the sensor proposed in this study. Furthermore, In the results of the experiment, it showed similar performance to the HFCT sensor.