• Proceedings of the KIEE Conference
• /
• 1994.11a
• /
• pp.322-325
• /
• 1994

Mareel and Bitmead proved the presence of chaotic signal in random noise by applying dead beat control theory to adaptive mechanism. In this paper robust adaptive theory is proposed. With the property of chaotic signal that has order and law, the proposed theory can enhance the control Performance by applying the recursive algorithm that uses dynamic relation which have small correlation. The performance of proposed algorithm is demonstrated with the computer simulation of position control of electric motor. In this simulation, the adaptive low is adopted to control electric motor and the Presence of chaotic signal in feedback signal is proved by using several method such as time series, fourier spectrum phase portrait method.

• Proceedings of the KIEE Conference
• /
• 2003.11c
• /
• pp.445-448
• /
• 2003

This paper presents a novel iris recognition method using wavelet transform and curve simplification. One-dimensional signals, which are calculated over circles on the iris, are decomposed into a multiple frequency bands. Each decomposed signal is approximated by a piecewise linear curve connecting node points. The curve is simplified by progressively removing unimportant node points while keeping the shape of the curve. Finally, a small number of node points represent features of each signal. Experiment results show that the presented method results in good performance in various noise environments.

• Journal of Mechanical Science and Technology
• /
• v.20 no.2
• /
• pp.197-204
• /
• 2006

The purpose of this study is to evaluate the AE characteristics for the basemetal, PWHT (post-weld heat treatment) and weldment specimens of SA-516 steel during fracture testing. Four-point bending and AE tests were conducted simultaneously. AE signals were emitted in the process of plastic deformation. AE signal strength and amplitude of the weldment was the strongest, followed by PWHT specimen and basemetal. More AE signals were emitted from the weldment samples because of the oxides, and discontinuous mechanical properties. AE signal strength and amplitude for the basemetal or PWHT specimen decreased remarkably compared to the weldment because of lower strength. Pre-cracked specimens emitted even lower event counts than the corresponding blunt notched specimens. Dimple fracture from void coalescence mechanism is associated with low-level AE signal strength for the basemetal or PWHT. Tearing mode and dimple formation were shown on the fracture surfaces of the weldment, but only a small fraction produced detectable AE.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.22 no.4
• /
• pp.658-664
• /
• 2013

In this paper, we present a case study of vibration suppression based on the application of active damping to the small boring process of a boring bar with diameter below ${\Phi}12$. The proposed active damping system consists of an acceleration sensor for real-time monitoring of the vibration signal, a driver for phase control in a computer program, and piezoelectric actuators for damping. In this system, the vibration signals are detected by the acceleration sensor and sent to the computer as an input. The phase shift parameter of the natural frequency of the input signal is sent to the data acquisition board in the computer and calculated by the phase control program. This study confirmed the effectiveness of this damping system, and it opens up the possibility of the development of active damping systems for small boring processes.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.11a
• /
• pp.631-633
• /
• 2005

For biohydrogen production, hydrogenase is a key enzyme. In the present work we performed search of [NiFe]-hydrogenases from hydrogen producing microorganisms using degenerate polymerase chain reaction (PCR) strategy. Degenerate primers were designed from the conserved region of [NiFe]-hydrogenase group I especially on structural genes encoding for catalytic subunit of [NiFe]-hydrogenase from bacteria producing hydrogen. Most of [NiFe]-hydrogenase (group I) are expressed via complex mechanism with aid of auxiliary protein and localized through twin-arginine translocation pathway. [NiFe]-hydrogenase is composed of large and small subunits for catalytic activity. It is known that only small subunit has signal peptide for periplasmic localization and large & small subunitscome together before localization. During this process, large subunit is treated by endopeptidase for maturation. Based on these information we used signal peptide sequence and C-terminal of large subunit by recognized by endopeptidase as templates for degenerate primers. About 2,900 bp of PCR products were successfully amplified using the designed degenerate primers from genomic DNAs of several microorganisms. The amplified PCR products were inserted into T-vector and then sequenced to confirm.

• Journal of Power System Engineering
• /
• v.7 no.2
• /
• pp.29-35
• /
• 2003

The monitoring and diagnostics of the rotating machinery have been received considerable attention for many years. The objectives are to classify the machinery condition and to find out the cause of abnormal condition. This paper describes a classification method of diagnosing the small reciprocating compressor for refrigerators using the artificial neural network and the wavelet transform. In order to extract salient features, the wavelet transform are used from primary noise signals. Since the wavelet transform decomposes raw time-waveform signals into two respective parts in the time space and frequency domain, more and better features can be obtained easier than time-waveform analysis. In the training phase for classification, self-organizing feature map(SOFM) and learning vector quantization(LVQ) are applied, and the accuracies of them ate compared with each other. This paper is focused on the development of an advanced signal classifier to automatize the vibration signal pattern recognition. This method is verified by small reciprocating compressors, for refrigerator and normal and abnormal conditions are classified with high flexibility and reliability.

• Publications of The Korean Astronomical Society
• /
• v.20 no.1 s.24
• /
• pp.125-134
• /
• 2005

In this paper, we propose a small-scale Gigabit VLBI observing system for the Korean VLBI Network (KVN) under construction. The system consists of high-speed sampler, IP-VLBI board, PC-VSI board, and software correlator. Radio signal received by receiver is sampled by high-speed sample. at 1 Gsps (Gigabit sample per second) rate with 2 bits quantization. The digitized signal is recorded in PC and the software correlator does the cross correlation. IP-VLBI board will be used for the geodesy VLBI observation, while PC-VSI board is for the astronomical VLBI observation. The PC-VSI board adopts the VSI-H (VLBI Standard Interface Hardware). The proposed system is based on commercial PCs and therefore can be built inexpensively.

• Journal of the Institute of Convergence Signal Processing
• /
• v.14 no.1
• /
• pp.33-38
• /
• 2013

In this paper, we propose an algorithm to track multi-small targets in infrared image sequences in case of dissipation or creation of targets by using the background estimation filter, Kahnan filter and mean shift algorithm. We detect target candidates in a still image by subtracting an original image from an background estimation image, and we track multi-targets by using Kahnan filter and target selection. At last, we adjust specific position of targets by using mean shift algorithm In the experiments, we compare the performance of each background estimation filters, and verified that proposed algorithm exhibits better performance compared to classic methods.

• Nutrition Research and Practice
• /
• v.17 no.5
• /
• pp.844-854
• /
• 2023

BACKGROUND/OBJECTIVES: Fucoidan, a polysaccharide content in brown algae, has been reported to inhibit the growth of cancer cells. The present study aimed to investigate the suppression effects of fucoidan on A549 non-small cell lung cancer cells migration. MATERIALS/METHODS: The anti-migratory activity of fucoidan in A549 cells was examined by wound healing assay and phalloidin-rhodamine staining in response to fucoidan (0-100 ㎍/mL) treatment for 48 h. Western blot analysis was performed to clarify the protein expressions relevant to migratory activity. RESULTS: Fucoidan (25-100 ㎍/mL) significantly suppressed A549 cells migration together with reduced the intensity of phalloidin-rhodamine which detect filopodia and lamellipodia protrusions at 48 h of treatment. The protein expression indicated that fucoidan significantly suppressed the phosphorylation of focal adhesion kinase (FAK), Src, and extracellular signal-related kinase (ERK). In addition, the phosphorylation of p38 in A549 cells was found to be increased. CONCLUSIONS: Our data conclude that fucoidan exhibits anti-migratory activities against lung cancer A549 cells mediated by inhibiting ERK1/2 and FAK-Src pathway.

• Proceedings of the KWS Conference
• /
• 1993.05a
• /
• pp.107-110
• /
• 1993