• 전력전자학회논문지
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• 제6권3호
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• pp.273-281
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• 2001

본 논문에서는 비선형 시스템을 제어하기 위한 CMAC 신경망을 제안한다. CMAC 신경망은 사람의 소뇌를 모방한 신경망으로서 복잡한 비선형 함수의 해를 수치적인 연산에 의해 구하지 않고 table look-up방식을 이용하기 때문에 학습이 타 신경망에 비해 월등히 빠르고 용이하며 제어신호를 출력하기 위한 계산시간이 거의 필요치가 않다. 본 논문에서는 제안한 제어기 구조의 타당성을 증명하기 위해 간단한 비선형 함수와 직류전동기 속도제어에 대한 CMAC 제어기를 시뮬레이션을 통하여 학습 제어기의 안정성 및 추적에러의 감소를 확인하였다. 또한 제안 CMAC 제어기를 실시간 장력제어에 적용하여 직류전동기의 속도를 제어하므로 시뮬레이션 값과 비슷한 장력제어를 보인으로서 유용성을 입증하였다.

• The Korean Journal of Physiology and Pharmacology
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• 제8권4호
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• pp.187-194
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• 2004

Middle cerebral artery occlusion (MCAO) results in cell death by activation of complex signal pathways for cell death and survival. Hypothermia is a robust neuroprotectant, and its effect has often been attributed to various mechanisms, but it is not yet clear. Upstream from the cell death promoters and executioners are several enzymes that may activate several transcription factors involved in cell death and survival. In this study, we immunohistochemically examined the phosphorylation of mitogen-activated protein kinase, extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 kinase during early period of the ischemic injury, following 2 hours (h) of transient MCAO. Increased phosphorylation of ERK and p38 was observed in the vessels at 3 h, neuron-like cells at 6 and 12 h and glia-like cells at 12 h. Activation of JNK was not remarkable, and a few cells showed active JNK following ischemia. Phosphorylation of Elk-1, a transcription factor, was reduced by ischemic insult. Hypothermia attenuated the activation of ERK, p38 and JNK, and inhibited reduction of Elk-1. These data suggest that signals via different MAPK family members converge on the cell damage process and hypothermia protects the brain by interfering with these pathways.

• KIEE International Transactions on Power Engineering
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• 제4A권1호
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• pp.33-41
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• 2004

Knowledge of partial discharge (PD) is important to accurately diagnose and predict the condition of insulation. The PD phenomenon is highly complex and seems to be random in its occurrence. This paper indicates the possible use of chaos theory for the recognition and distinction concerning PD signals. Chaos refers to a state where the predictive abilities of a systems future are lost and the system is rendered aperiodic. The analysis of PD using deterministic chaos comprises of the study of the basic system dynamics of the PD phenomenon. This involves the construction of the PD attractor in state space. The simulation results show that the variance of an orthogonal axis in an attractor of chaos theory increases according to the magnitude and the number of PDs. However, it is difficult to clearly identify the characteristics of the PDs. Thus, we calculated the magnitude on an orthogonal axis in an attractor using singular value decomposition (SVD) and principal component analysis (PCA) to extract the numerical characteristics. In this paper, we proposed the condition monitoring method for gas insulated switchgear (GIS) using SVD for efficient calculation of the variance. Thousands of simulations have proven the accuracy and effectiveness of the proposed algorithm.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 반도체재료
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• pp.75-78
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• 2001

Recently, the HFPD measurement testing is widely used in partial discharge measurement of HV machines because HFPD measurement testing receives less influence of external noise and has a merit of good sensitivity. Also HFPD testing is able to offer the judgement standard of degradation level of HV machine and can detect discharge signals in live-line. Therefore it is very useful method compare to previous conventional PD testing method and effective diagnosis method in power transformer that requires live-line diagnosis. But partial discharges have very complex characteristics of discharge pattern so it is required continuous research to development of precise analysis method. In recent, the study of partial discharge is carrying out discover of initial defect of power equipment through condition diagnosis and system development of degradation diagnosis using HFPD(High Frequency Partial Discharge) detection. In this study, simulated transformer is manufactured and HFPD occurred from transformer is measured with broad band antenna in real time, the degradation grade of transformer is analyzed through produced patterns in simulated transformer according to applied voltages.

• 약학회지
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• 제50권2호
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• pp.93-98
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• 2006

Human foamy virus (HFV) integrase mediates integration of viral c-DNA into cellular DNA. In this process, HFV prointegration complex (PIC) in which integrase is a key component moves to nuclei of the infected cells and leads to integration of viral DNA to the cellular genome, which is essential in viral life cycle. In general nuclear localization signals (NLS) have been suggested to be involved in localizing retroviral PIC to nuclei, but the mechanisms for nuclear localization of the HFV PIC remains unclear. To functionally identify the NLS of HFV integrase, various subdomains of the protein were expressed as GFP fusions and their subcellular locations were analyzed with confocal laser scanning microscopy. Wild type HFV integrase was karyophilic by targeting the fusion protein to nuclei of the COS-1 and 293T cells. Our results showed that strong NLS of HFV integrase was mapped to the C-terminal regions. In addition the karyophilic properties of N-terminal and central regions are not individually strong enough to direct localization of the fusion proteins to nuclei, but their cooperative activity for nuclear import was confirmed.

• 제어로봇시스템학회논문지
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• 제18권4호
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• pp.375-383
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• 2012

Together with the GPS-based approach, geolocation through mobile communication networks is a key technology for location-based service. Since the Mobile WiMAX system is considered as a candidate for fourth-generation mobile systems, it is important to investigate its location capability. The geolocation of Mobile WiMAX can be realized when the preamble symbols in the down-link channel are appropriately used for a TDOA (Time-Difference-of-Arrival) approach. However, the cellular structure of Mobile WiMAX inevitably generates co-channel interference, and it is difficult for the mobile terminal to acquire distance measurements from multiple base stations. Therefore, for geolocation via multilateration using the Mobile WiMAX network, it is very important to increase hearability. This paper proposes a geolocation method for Mobile WiMAX which employs interference cancellation and preamble signal overlapping for the enhancement of hearability. A novel interference cancellation strategy for complex-valued Mobile WiMAX signals is presented which has an iterative structure. Simulation results show that the proposed geolocation method provides the user's position with an accuracy of less than 20 m through the Mobile WiMAX cellular network if there is no multi-path or NLOS (None-Line-of-Sight).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 전기설비전문위원
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• pp.10-12
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• 2009

Electromagnetic Interference(EMI) in electric railway operation has become increasingly important. The components within very high power electronic, and the circuits for treating low-level signals, comprise complex system that must coexist and be highly reliable. To study it, It were included how much the HEMU-400X generates EMI and it has an effect on the power conversion units which resulted from Power Line Disturbance (PLD) phenomenon by contact loss during its running. In this study, the dynamic characteristic of a contact wire and pantograph suppling electrical power to high-speed trains are investigated. The analysis of the loss of contact based on Power Simulator program software is performed to develop power line disturbance model suitable for high speed operation. It is confirmed that a contact wire and pantograph model are necessary for studying the dynamic behavior of the pantograph system.

• 한국생산제조학회지
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• 제24권4호
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• pp.414-420
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• 2015

In this study, the linear quadratic Guassian loop transfer recovery (LQG/LTR) control technique was combined with an integrator and applied to an inchworm having piezoelectric actuators for precise motion tracking. The piezoelectric actuator showed nonlinear response characteristics, including hysteresis, due to its ferroelectric characteristics and the residual displacement phenomenon. This paper proposes a feedback control scheme using the LQG/LTR controller with an integrator to improve the ability to track the response to complex input signals and to suppress the phenomenon of hysteresis and residual vibration. Experimental results show that the developed feedback control system for an inchworm can track the various motion contours quickly without residual vibration or overshoot.

• 한국수산과학회지
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• 제48권2호
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• pp.207-220
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• 2015

This study identified the species-specific, frequency-dependent characteristics of broadband acoustic scattering that facilitate classifying fish species using the pulse compression (PC) technique. Controlled acoustic scattering laboratory experiments were conducted with nine commercially important fish species using linear chirp signals (95-220 kHz) over an orientation angle range of ${\pm}45^{\circ}$ in the dorsal plane at approximately $1^{\circ}$ increments. The results suggest that the angular-dependent characteristics of the broadband echoes and the frequency-dependent variability in target strength (TS) were useful for inferring the fish species of interest. The scattering patterns in the compressed pulse output were extremely complex due to morphological differences among fish species, but the x-ray images strongly suggested that spatial separation correlated well with scattering for the head, skeleton, bone, otoliths, and swim bladder within each specimen.

• Asian Pacific Journal of Cancer Prevention
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• 제17권3호
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• pp.1003-1008
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• 2016

Breast cancer is now the leading cause of cancer death in women worldwide. Cancer progression is driven not only by cancer cell intrinsic alterations and interactions with tumor microenvironment, but also by systemic effects. Integration of multiple profiling data may provide insights into the underlying molecular mechanisms of complex systemic processes. We performed a bioinformatic analysis of two public available microarray datasets for breast tumor stroma and peripheral blood mononuclear cells, featuring integrated transcriptomics data, protein-protein interactions (PPIs) and protein subcellular localization, to identify genes and biological pathways that contribute to dialogue between tumor stroma and the peripheral circulation. Genes of the integrin family as well as CXCR4 proved to be hub nodes of the crosstalk network and may play an important role in response to stroma-derived chemoattractants. This study pointed to potential for development of therapeutic strategies that target systemic signals travelling through the circulation and interdict tumor cell recruitment.