• Journal of Navigation and Port Research
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• v.40 no.6
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• pp.385-390
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• 2016

ELoran Systems can provide Position, Navigation, and Time services with comparable performance to Global Positioning Systems (GPS) as a back up or alternative system. High timing and navigation performance can be achieved by eLoran signals because eLoran receivers use "all-in-view" reception. This incorporates Time of Arrival (TOA) signals from all stations in the service range because each eLoran station is synchronized to Coordinated Universal Time (UTC). Transmission station information and the differential Loran correction data are transmitted via an additional Loran Data Channel (LDC) on the transmitted eLoran signal such that eLoran provides improved Position Navigation and Timing (PNT) over legacy Loran. In this paper, we propose a technique for adapting the delay time compensation values in eLoran timing receivers to provide precise time comparison. For this purpose, we have designed a system that measures time delay from the crossing point of the third cycle extracted from the current transformer at the end point of the transmitter. The receiver delay was measured by connecting an active H-field, an E-field and a passive loop antenna to a commercial eLoran timing receiver. The common-view time transfer technique using the calibrated eLoran timing receiver improved the eLoran transfer time. A eLoran timing receiver calibrated by this method can be utilized in the field for precise time comparison as a GNSS backup.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.4
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• pp.351-359
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• 2011

In a structure, damage can occur at several scales from micro-cracking to corrosion or loose bolts. This makes the identification of damage difficult with one mode of sensing. Hence, a multi-mode actuated sensing system is proposed based on a self-sensing circuit using a piezoelectric sensor. In the self sensing-based multi-mode actuated sensing, one mode provides a wide frequency-band structural response from the self-sensed impedance measurement and the other mode provides a specific frequency-induced structural wavelet response from the self-sensed guided wave measurement. In this study, an experimental study on the pipeline system is carried out to verify the effectiveness and the robustness of the proposed structural health monitoring approach. Different types of structural damage are artificially inflicted on the pipeline system. To classify the multiple types of structural damage, a supervised learning-based statistical pattern recognition is implemented by composing a two-dimensional space using the damage indices extracted from the impedance and guided wave features. For more systematic damage classification, several control parameters to determine an optimal decision boundary for the supervised learning-based pattern recognition are optimized. Finally, further research issues will be discussed for real-world implementation of the proposed approach.

• Science of Emotion and Sensibility
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• v.14 no.4
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• pp.653-662
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• 2011

As technology in 3D industry has rapidly advanced, a lot of studies primarily focusing on visual function and cognition have become vigorous. However, studies on effect of 3D visual fatigue on autonomic nervous system have not less been conducted. Thus, this study was to identify and determine the effect that might have a negative influence on sympathetic nervous system, parasympathetic nervous system, and cardiovascular system. Fifteen undergraduates (female: 9, mean age: $22.53{\pm}2.55$) participated and were sat on a comfortable chair, viewing a 3D content during about 1 hour. Cardiac responses like SDNN(standard deviation of RR intervals), RMS-SD(root mean squared successive difference), and HF/LF ratios extracted from the measured PPG(Photo-PlethysmoGram) before viewing 3D were compared to those after viewing 3D. The results showed that after subjects watched the 3D, responses in sympathetic nervous system and parasympathetic nervous system were activated and deactivated, respectively relative to those before watching the 3D. The results showed that HF/LF ratio, Ln(LF), and Ln(HF) after viewing 3D were significantly reduced relative to those before viewing 3D. No significant effects were observed in SDNN and RMS-SD. Results obtained in this study showed that visual fatigue induced by watching 3D adversely influenced autonomic nervous system, and thereby reduced heart rate variability causing sympathetic nervous acceleration.

• Science of Emotion and Sensibility
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• v.14 no.4
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• pp.627-636
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• 2011

The purpose of this study is to develop the multi-modal interaction system. This system provides realistic and an immersive experience through multi-modal interaction. The system recognizes user behavior, intention, and attention, which overcomes the limitations of uni-modal interaction. The multi-modal interaction system is based upon gesture interaction methods, intuitive gesture interaction and attention evaluation technology. The gesture interaction methods were based on the sensors that were selected to analyze the accuracy of the 3-D gesture recognition technology using meta-analysis. The elements of intuitive gesture interaction were reflected through the results of experiments. The attention evaluation technology was developed by the physiological signal analysis. This system is divided into 3 modules; a motion cognitive system, an eye gaze detecting system, and a bio-reaction sensing system. The first module is the motion cognitive system which uses the accelerator sensor and flexible sensors to recognize hand and finger movements of the user. The second module is an eye gaze detecting system that detects pupil movements and reactions. The final module consists of a bio-reaction sensing system or attention evaluating system which tracks cardiovascular and skin temperature reactions. This study will be used for the development of realistic digital entertainment technology.

• Journal of KIISE
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• v.44 no.6
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• pp.587-594
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• 2017

Recently, motor imagery electroencephalogram(EEG) based Brain-Computer Interface(BCI) systems have received a significant amount of attention in various fields, including medicine and engineering. The Common Spatial Pattern(CSP) algorithm is the most commonly-used method to extract the features from motor imagery EEG. However, the CSP algorithm has limited applicability in Small-Sample Setting(SSS) situations because these situations rely on a covariance matrix. In addition, large differences in performance depend on the frequency bands that are being used. To address these problems, 4-40Hz band EEG signals are divided using nine filter-banks and Regularized CSP(R-CSP) is applied to individual frequency bands. Then, the Mutual Information-Based Individual Feature(MIBIF) algorithm is applied to the features of R-CSP for selecting discriminative features. Thereafter, selected features are used as inputs of the classifier Least Square Support Vector Machine(LS-SVM). The proposed method yielded a classification accuracy of 87.5%, 100%, 63.78%, 82.14%, and 86.11% in five subjects("aa", "al", "av", "aw", and "ay", respectively) for BCI competition III dataset IVa by using 18 channels in the vicinity of the motor area of the cerebral cortex. The proposed method improved the mean classification accuracy by 16.21%, 10.77% and 3.32% compared to the CSP, R-CSP and FBCSP, respectively The proposed method shows a particularly excellent performance in the SSS situation.

• The Journal of Pediatrics of Korean Medicine
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• v.28 no.3
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• pp.31-46
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• 2014

Objectives Forsythiae Fructus treatment has been used for inflammatory and allergic diseases in Korean Medicine. Nevertheless, the mechanism of action and the cellular targets are not understood well. The pathogenesis of allergic diseases are associated with Th2 cytokines such as IL-13, MIP-$1{\alpha}$, IL-13, IL-5, GM-CSF, IL-4, TNF-${\alpha}$ and IL-6, which are secreted by the mast cells. This study was conducted to investigate the effects of Forsythiae Fructus extracts (FF) on Th2 cytokines expression and signal transduction in MC/9 mast cells. Methods In the study, MC/9 mast cells were stimulated with DNP-IgE for 24 hours and then treated separately with CsA $10{\mu}g/m{\ell}$ and varying doses of FF for one hour. MC/9 mast cells stimulated with DNP-IgE was the control group, a treatment with CsA was the positive control group and a treatment with varying doses FF was the experimental groups. The mRNA levels of IL-13, IL-5, GM-CSF, IL-4, TNF-${\alpha}$, IL-6 were analyzed with Real-time PCR. The levels of IL-13, MIP-$1{\alpha}$ were measured using enzyme-linked immunosorbent assays(ELISA). NFAT, AP-1 and NF-${\kappa}B$ p65 were examined by Western blot analysis. Results 1. FF were observed to suppress the mRNA expression of IL-13, IL-5, GM-CSF, IL-4, TNF-${\alpha}$, IL-6 in comparison to DNP-IgE control group. 2. FF also has inhibited the IL-13, MIP-$1{\alpha}$ production significantly in comparison to DNP-IgE control group. 3. Western blot analysis of transduction factors involving Th2 cytokines expression has revealed a prominent decrease of the mast cell specific transduction factors including NFAT-1, NFAT-2, c-Jun, and NF-${\kappa}B$ p65 but c-Fos. Conclusions In conclusion, the anti-allergenic activities of FF may be strongly related to the regulation of transcription factors NFAT-1, NFAT-2, c-Jun, and NF-${\kappa}B$ p65 causing inhibition of Th2 cytokines in mast cells.

• Clinical and Experimental Pediatrics
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• v.48 no.6
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• pp.634-639
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• 2005

Purpose : An understanding of the immunological process is required if primary prevention of atopic diseases is to be developed in early childhood. But, it is too hard to distinguish atopy from nonatopy under the age of two clinically, because the expression of phenotype and cytokines is vague in early childhood. We evaluated DNA methylation changes at Th2 interleukin-4 gene in peripheral blood from atopic children. Methods : We selected 15 allergic children(mild : eight, moderate to severe : seven) and seven normal controls by using family allergy scores and clinical histories. We measured Total IgE and Der f II specific IgE levels and cultured peripheral blood mononuclear cells with Der f II stimulation and extracted DNA from Der f II specific T cells. We examined the change of CpG methylation in DNA from atopic and nonatopic children. Results : In T cells from normal children, IL-4 DNA were predominantly methylated; otherwise, CpG demethylation occurred in Der f II specific T cells from allergic children. Conclusion : IL-4 DNA methylation changes occurred in T genes from allergic children and DNA methylation assay in early childhood.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.595-601
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• 2018

The era of autonomous vehicles, which drive themselves and in whose operation the driver does not intervene, is fast approaching. The safety of autonomous vehicles can be guaranteed only if they recognize the road infrastructure. However, the road infrastructure consists of road safety facilities, traffic operation systems, and cross-sectional concerns, which include a variety of components, such as types, shapes, and sizes. Therefore, it is necessary to prioritize the road information. This study was conducted to select the priority with which the road infrastructure attributes should be acquired using the AHP (Analytical Hierarchy Process) method. The road infrastructure attributes were categorized into 2 levels, levels 1 and 2, which consisted of 3 and 26 types of attributes, respectively. As a result of the AHP analysis, it was found that the highest priorities of the road infrastructure are the road safety facilities, traffic operation systems and cross sectional concerns. Also, in level-2, the priorities of the safety barriers (road safety facilities), traffic signals (traffic operation systems), and the median (cross sectional) are the highest. Also, this study provides application examples of road infrastructure extraction with the Point Cloud. The results are expected to support the recognition of technology for autonomous vehicles.

• Applied Biological Chemistry
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• v.51 no.2
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• pp.129-135
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• 2008

Berberine is an isoquinoline alkaloid used in traditional Chinese medicine and has been isolated from a variety of plants, such as Coptis chinensis and Phellodendron amurense. It has a wide spectrum of clinical applications such as in anti-tumor, anti-microbial, and anti-inflammatory activities. However, it is still unknown that berberine related with reactive oxygen species (ROS)-mediated apoptosis pathway in human hepatoma HepG2 cells. In the present study, we are examined the molecular mechanism of ROS- and p38 MAP kinase-mediated apoptosis by berberine in HepG2 cells. Berberine increased cytotoxicity effects by time- and does-dependent manner. $LD_{50}$ was detected 50 ${\mu}M$ at 48h of exposure to berberine. Nuclei cleavage and apoptotic DNA fragmentation were observed in cells treated with 50 ${\mu}M$ of berberine for 48h. Moreover, berberine induced the activating of caspase-3, p53, p38 and Bax expression, whereas the expression of anti-apoptotic signaling pathways, Bcl-2, was decreased. Additionally, berberine-treated cells had an increased level of generation of ROS and nitric oxide (NO). These results indicated that berberine induces apoptosis of HepG2 cells may be mediated oxidative injury acts as an early and upstream change, triggers mitochondrial dysfunction, Bcl-2 and Bax modulation, p38 and p53 activation, caspase-3 activation, and consequent leading to apoptosis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11A
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• pp.1263-1270
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• 2004

A low-power 64-point FFT/IFFT processor core is designed, which is an essential block in OFDM-based wireless LAM modems. The radix-2/418 DIF (Decimation-ln-Frequency) FFT algorithm is implemented using R2SDF (Radix-2 Single-path Delay Feedback) structure. Some design techniques for low-power implementation are considered from algorithm level to circuit level. Based on the analysis on infernal data flow, some unnecessary switching activities have been eliminated to minimize power dissipation. In circuit level, constant multipliers and complex-number multiplier in data-path are designed using truncation structure to reduce gate counts and power dissipation. The 64-point FFT/IFFT core designed in Verilog-HDL has about 28,100 gates, and timing simulation results using gate-level netlist with extracted SDF data show that it can safely operate up to 50-MHz＠2.5-V, resulting that a 64-point FFT/IFFT can be computed every 1.3-${\mu}\textrm{s}$. The functionality of the core was fully verified by FPGA implementation using various test vectors. The average SQNR of over 50-dB is achieved, and the average power consumption is about 69.3-mW with 50-MHz＠2.5-V.