• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.697-700
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• 2005

An adaptive fuzzy sliding-mode controller (SMC) for uncertain or ill-defined single-input single-output (SISO) nonaffine nonlinear systems is proposed. By using the universal approximation property of the fuzzy logic system (FLS), it is tuned on-line to cancel the unknown system nonlinearity. We adopt a self-structuring FLS to guarantee global stability of the closed-loop system rather than semi=global boundedness. The control and adaptive laws are derived so that the estimated fuzzy parameters are bounded and the sliding condition is satisfied.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권5호
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• pp.315-322
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• 2004

A direct adaptive state-feedback controller for highly nonlinear systems is proposed. This paper considers uncertain or ill-defined nonaffine nonlinear systems and employs a static fuzzy logic system (FLS). The employed FLS estimates. and adaptively cancels an unknown plant nonlinearity using its proved universal approximation property. A control law and adaptive laws for unknown fuzzy parameters and bounding constant are established so that the whole closed-loop system is stable in the sense of Lyapunov. The tracking error is guaranteed to be uniformly asymptotically stable rather than uniformly ultimately bounded with the aid of an additional robustifying control term. No a priori knowledge of an upper bound on an lumped uncertainty is required.

• Steel and Composite Structures
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• 제43권3호
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• pp.363-373
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• 2022

As a key reinforcement connection between a tower and a substructure in offshore wind turbine system, the transition piece is inevitably subjected to cyclic dynamic environmental loads such as wind, current and wave. Therefore, well designed transition piece with high strength and good fatigue resistance is of great significance to the structural safety and reliability of offshore wind power systems. In this study, the structural behavior of the transition piece was studied by an extensive sets of finite element analyses. Three widely used types of transition piece were considered. The characteristics of stress development, fatigue life and weight depending on the type of the transition piece were investigated in the ultimate limit state (ULS) and the fatigue limit state (FLS) of a 5-MW offshore wind turbine to be placed in Korea. An optimal form of the transition piece was proposed based on this parametric study.

• Advances in Computational Design
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• 제8권3호
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• pp.191-217
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• 2023

The objective of this study was to evaluate the foundation structure of a 3.6-MW wind turbine generator (WTG) installed offshore in Western Korea. The ultimate limit state (ULS) and fatigue limit state (FLS) of the multi-pile steel foundation (MSF) installed at the Saemangeum offshore wind farm were structurally investigated using the finite element (FE) software, ANSYS Workbench 19.0. According to the ULS analysis, no plastic deformation was found in any of the components constituting the substructure. At the same time, the maximal stress value reached the calculation limit of 335 MPa. According to the FLS results, the stress concentration factor (SCF) ranged from 1.00 to 1.88 in all components. The results of this study can be applied to determine the optimal design for MSFs.

• 센서학회지
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• 제32권5호
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• pp.313-319
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• 2023

In this study, we propose a method to improve the accuracy of acoustic odometry using optimal frame interval selection for Fourier-based image registration. The accuracy of acoustic odometry is related to the phase correlation result of image pairs obtained from the forward-looking sonar (FLS). Phase correlation failure is caused by spurious peaks and high-similarity image pairs that can be prevented by optimal frame interval selection. We proposed a method of selecting the optimal frame interval by analyzing the factors affecting phase correlation. Acoustic odometry error was reduced by selecting the optimal frame interval. The proposed method was verified using field data.

• 시멘트 심포지엄
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• 19호
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• pp.14-17
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• 1991

The electrostatic precipitator is known to the cement industry as the preferred dedusting equipment for the main dust emission sources. To understand the function better, a short description of the theory of precipitation is presented, with the factors in

• IMMUNE NETWORK
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• 제2권4호
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• pp.208-216
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• 2002

Background: Reactive oxygen and nitrogen are produced by rheumatoid arthritis (RA) synovial tissue and can induce mutations in key genes. Normally, this process is prevented by a DNA mismatch repair (MMR) system that maintains sequence fidelity. Key members of the MMR system include MutS${\alpha}$ (comprised of hMSH2 and hMSH6), which can sense and repair single base mismatches and 8-oxoguanine, and MutS${\beta}$ (comprised of hMSH2 and hMSH3), which repairs longer insertion/deletion loops. Methods: To provide further evidence of DNA damage, we analyzed synovial tissues for microsatellite instability (MSI). MSI was examined by PCR on genomic DNA of paired synovial tissue and peripheral blood cells (PBC) of RA patients using specific primer sequences for 5 key microsatellites. Results: Surprisingly, abundant MSI was observed in RA synovium compared with osteoarthritis (OA) tissue. Western blot analysis of the same tissues for the expression of MMR proteins demonstrated decreased hMSH6 and increased hMSH3 in RA synovium. To evaluate potential mechanisms of MMR regulation in arthritis, fibroblast-like synoviocytes (FLS) were isolated from synovial tissues and incubated with the nitric oxide donor S-nitroso-N-acetylpenicillamine (SNAP). Western blot analysis demonstrated constitutive expression of hMSH2, 3 and 6 in RA and OA FLS. When FLS were cultured with SNAP, the RA synovial pattern of MMR expression was reproduced (high hMSH3, low hMSH6). Conclusion: Therefore, oxidative stress can relax the DNA MMR system in RA by suppressing hMSH6. Decreased hMSH6 can subsequently interfere with repair of single base mutations, which is the type observed in RA. We propose that oxidative stress not only creates DNA adducts that are potentially mutagenic, but also suppresses the mechanisms that limit the DNA damage.

• 한국인터넷방송통신학회논문지
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• 제11권1호
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• pp.23-28
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• 2011

본 논문은 무선 인지 센서 네트워크에서 2차 사용자를 위한 효율적 채널 선택 알고리즘을 제안한다. 제안된 알고리즘은 러닝 오토메타와 퍼지 로직을 기반하고 있으며, 러닝 오토메타는 무선 전송 채널을 2차 사용자가 학습하여 그 결과를 채널 선택 확률값로 나타내며, 퍼지 로직은 최종 채널 선택을 위하여 다양한 입력 변수를 고려할 수 있도록 한다. 즉, 퍼지 로직은 러닝 오토메타의 결과인 채널 선택 학률값, 기사용자와 2차사용자 사이의 채널 SNR, 송수신 2차 사용자들 사이의 SNR값을 고려하여 다중의 가용 채널로부터 최적으로 전송 채널을 선택할 수 있도록 한다. 시뮬레이션 결과를 통해, 제안된 알고리즘이 기존 알고리즘들 보다 높은 처리율(throughput)을 제공할 수 있음을 보였다.

• Journal of Ginseng Research
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• 제45권5호
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• pp.575-582
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• 2021

Background: In ginseng, there exists a glycolipoprotein complex with a special form of lipid LPAs called Gintonin. The purpose of this study is to show that Gintonin has a therapeutic effect on rheumatoid arthritis through LPA2 receptors. Methods: Fibroblast-like synoviocytes (FLS) were treated with Gintonin and stimulated with interleukin (IL)-1β. The antioxidant effect of Gintonin was measured using MitoSOX and H₂DCFDA experiments. The anti-arthritic efficacy of Gintonin was examined by analyzing the expression levels of inflammatory mediators, phosphorylation of mitogen-activated protein kinase (MAPK) pathways, and translocation of nuclear factor kappa B (NF-κB)/p65 into the nucleus through western blot. Next, after treatment with LPAR2 antagonist, western blot analysis was performed to measure inflammatory mediator expression levels, and NF-κB signaling pathway. Carrageenan/kaolin-induced arthritis rat model was used. Rats were orally administered with Gintonin (25, 50, and 100 mg/kg) every day for 6 days. The knee joint thickness, squeaking score, and weight distribution ratio (WDR) were measured as the behavioral parameters. After sacrifice, H&E staining was performed for histological analysis. Results: Gintonin significantly inhibited the expression of iNOS, TNF-α, IL-6 and COX-2. Gintonin prevented NF-κB/p65 from moving into the nucleus through the JNK and ERK MAPK phosphorylation in FLS cells. However, pretreatment with an LPA2 antagonist significantly reversed these effects of Gintonin. In the arthritis rat model, Gintonin suppressed all parameters that were measured. Conclusion: This study suggests that LPA2 receptor plays a key role in mediating the anti-arthritic effects of Gintonin by modulating inflammatory mediators, the MAPK and NF-κB signaling pathways.

• 문화기술의 융합
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• 제7권2호
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• pp.339-343
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• 2021

본 연구는 복숭아 '천홍'의 착과 수준(fruiting level, FLs)을 3수준(FL-Low, Middle, High)으로 하여 결과지의 신초 발달과 성숙 과실의 무게 및 당도를 비교하였다. 결과지당 신초수 분포 비율에서는 FL-Low의 1-2개(42%), FL-Middle의 1개(47%), FL-High의 1개(42%)에서 가장 높았다. 과실 무게 및 당도 분포 비율에서는 FL-Low의 210-270g (50%) 및 10-12Brix (44%), FL-Middle의 180-240g (60%) 및 10-12Brix (59%), FL-High의 180-240g(60%) 및 11-13Brix (48%)에서 가장 높았다. 그리고 FL-High에서만 과중과 결과지 신초수 간 상관성을 나타내었다. 그리고 당도(y)에 대하여 과실 무게(x)는 FL-L에서 y=0.0126x+8.1857, 그리고 결정계수((R²)가 0.1964으로 P≤0.01 유의수준에서 매우 높은 관계성이 인정되었다.