• Journal of Korea Multimedia Society
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• v.13 no.7
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• pp.973-982
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• 2010

In this paper, we proposed the single-channel adaptive noise canceller for the enhancement of heart sound (HS) in the auscultation signal. In case of either normal or emergency, a HS diagnosis is difficult due to the various signal source in the chest. Therefore, the HS enhancement is necessary. The conventional active noise canceller(ANC) has two channel, main signal and reference signal. For signal channel, the reference signal in ANC was generated by the proposed HS analyser and BS-Gate based on the characteristic of HS. This reference signal is suitable to the ANC condition. Experimental data were acquisited from MP36, SS30L in BIOPAC Inc., By the experiment, we confirmed that the proposed single-channel ANC was efficient for HS enhancement. And by the comparison with active linear enhancement, it was validate that the proposed ANC is not affected by the variation of a heartbeat.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.5
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• pp.694-702
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• 2022

This paper shows a small and low-powered wireless communication system based on the ATSC broadcasting system using the ISM frequency band that can be used as a PBS(Personal Broadcasting System). It is designed to demonstrate a channel-adaptive CR(Cognitive Radio) system to provide a better service quality in the unlicensed band where co-channel interference exists. And it achieved very reliable communications by a closed-loop active phased array antenna. This ATSC-based personal broadcasting platform can be modified easily with given flexibility by using GNU Radio as an open-source signal processing platform based on USRP and implementing additional functions in FPGA. In addition, the chosen communication frequency resource can be managed and controlled by the return channel that transmits the channel status and communication parameters between transmission and reception in real-time.

• Journal of Korea Water Resources Association
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• v.42 no.7
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• pp.579-589
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• 2009

Hwang River in South Korea, has experienced channel adjustments due to dam construction. Hapcheon main dam and re-regulation dam. The reach below the re-regulation dam (45 km long) changed in flow regime, channel width, bed material distribution, vegetation expansion, and island formation after dam construction. The re-regulation dam dramatically reduced annual peak flow from 654.7 $m^3$/s to 126.3 $m^3$/s and trapped the annual 591 thousand $m^3$ of sediment load formerly delivered from the upper watershed since the completion of the dam in 1989. An analysis of a time series of aerial photographs taken in 1982, 1993, and 2004 showed that non-vegetated active channel width narrowed an average of 152 m (47% of 1982) and non-vegetated active channel area decreased an average of 6.6 km2 (44% of 1982) between 1982 and 2004, with most narrowing and decreasing occurring after dam construction. The effects of daily pulses of water from peak hydropower generation and sudden sluice gate operations are investigated downstream of Hapcheon Dam in South Korea. The study reach is 45 km long from the Hapcheon re-regulation Dam to the confluence with the Nakdong River. An analysis of a time series of aerial photographs taken in 1982, 1993, and 2004 showed that the non-vegetated active channel width narrowed an average of 152 m (47% reduction since 1982). The non-vegetated active channel area also decreased an average of 6.6 $km^2$ (44% reduction since 1982) between 1982 and 2004, with most changes occurring after dam construction. The average median bed material size increased from 1.07 mm in 1983 to 5.72 mm in 2003, and the bed slope of the reach decreased from 0.000943 in 1983 to 0.000847 in 2003. The riverbed vertical degradation is approximately 2.6 m for a distance of 20 km below the re-regulation dam. It is expected from the result of the unsteady sediment transport numerical model (GSTAR-1D) steady simulations that the thalweg elevation will reach a stable condition around 2020. The model also confirms the theoretical prediction that sediment transport rates from daily pulses and flood peaks are 21 % and 15 % higher than their respective averages.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.4
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• pp.318-327
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• 2017

It is essential for the near-field receiving measurement to make beam pattern and check the performance of a active phased array antenna system. Also, we could obtain compensation value for mono-pulse function through the near-field receive test, however, if the radar has many frequency channel, the test would take long time and hard effort. So it is needed that frequency channels are selected for measurement and calculates the values for other frequency channels to improve efficiency in development and manufacture. In this case, the phase variations in sum and del channels would be checked. The phase measurement includes un-linear characteristic because of wrapping effect. Generally, radars have similar path length in sum and del channel, but if a radar has a electrical length gap between sum and del channel, errors could occur by phase's wrapping effect. In this paper, the interpolation method's error caused by electrical length gap is checked and the effective method for frequency channel selection to avoid wrapping effect is introduced.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.12 s.117
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• pp.1252-1261
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• 2006

This paper summarizes theoretical work on the multichannel decentralized feedback control of sound radiation from aircraft trim panels using piezoceramic actuators. The aircraft trim panels are generally honeycomb structures designed to meet the design requirement of low weight and high stiffness. They are resiliently-mounted to the fuselage for the passive reduction of noise transmission. It is motivated by the localization of reduction in vibration of single channel active trim panels. 12-channel decentralized feedback control systems are investigated in terms of the reduction of noise and vibration for three configurations of sensor actuator pairs. Local coupling of the closely-spaced sensor and actuator pairs was modeled using single degree of freedom systems. The multichannel control system is characterized using the state-space model. For the stability point of view, the relative stability or robustness is evaluated by comparing the real part of eigenvalues of the system matrix for the three configurations. The control performance is also evaluated and compared for the three configurations. It is found that the multichannel system can lead to the globalization of the reduction in vibration and radiated noise. It does not appear to yield a significant improvement in the vibration because of decreased gain margin. However, the reduction in the radiated noise is remarkably improved due to the variation of the vibration pattern with the actuation configurations.

• Journal of Ginseng Research
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• v.31 no.2
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• pp.69-73
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• 2007

Since chemical structures of ginsenoside as active ingredient of Panax ginseng are known, accumulating evidence have shown that ginsenoside is one of bio-active ligands through the diverse physiological and pharmacological evaluations. Chemical structures of ginsenoside could be divided into three parts depending on diol or triol ginsenoside: Steroid- or cholesterol-like backbone structure, carbohydrate portions, which are attached at the carbon-3, -6 or -20, and aliphatic side chain coupled to the backbone structure at the carbon-20. Ginsenosides also exist as stereoisomer at the carbon-20. Bioactive ligands usually exhibit the their structure-function relationships. In ginsenosides, there is little known about the relationship of chemical structure and biological activity. Recent reports have shown that ginsenoside $Rg_3$, one of active ginsenosides, exhibits its differential physiological or pharmacological actions depending on its chemical structure. This review will show how ginsenoside $Rg_3$, as a model compound, is functionally coupled to voltage-gated ion channel or ligand-gated ion channel regulations in related with its chemical structure.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.6
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• pp.589-600
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• 1999

Audible noise of UPS(uninterruptible power supply) with small rated [Xlwer is usually generattxl by the c cooling fan‘ For active noise control for radiated noise of UPS, it is adequate to apply multiple-channel F FXLMS algorithm based on Filten어 x LM~longrightarrow algorithm. In this paper, to reduce the audible noise of UPS‘ Its m noise characteristics of UPS are an띠yzed and active noise control by using 이ffiMOClVlultiple- Reference/ M Multiple-Output) FXLMS algorithm is perf‘onned. Also, noise reduction characteristics are shown by computer S simulation and experimental results.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.5
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• pp.205-215
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• 2006

In this paper an optical power meter using Hadamard transform, which can be used in multiple channel optical elements alignment system, is proposed. A traditional optical power meter in multiple channel optical elements alignment system is able to judge how well the elements are aligned each other by measuring optical power of the first and the last two channels with at least two detectors. It has critical drawback that the alignment accuracy per channel is dependent on the number of detectors. The proposed optical power meter can get noise reduction by the Hadamard transform based multiplexing technique. The Hadamard transform based multiplexing technique using spatial light modulators is distinguished by the best enhancement of signal-to-noise ratio (SNR) for the reconstructed signals. Moreover, the noise reduction increases with increasing the order of multiplexing, namely the number of optical element channels. The proposed system is implemented by PDLC (Polymer Dispersed Liquid Crystal) mask which is operated by electric filed and generates optimal multiplexing patterns based on the Hadamard transform and single detector. It means that we obtain not only the each channel's optical power of multiple channel elements at once but also the best enhancement of SNR with single detector. Experimental results show that the proposed optical power meter is suitable for an active optical alignment system for multiple channel optical elements.

• Ocean and Polar Research
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• v.24 no.3
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• pp.289-300
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• 2002

The Lago Sofia conglomerates encased in the Cretaceous Cerro Toro Formation, southern Chile, represent a gigantic submarine channel system developed along a foredeep trough. The channel system consists of several tributaries along the trough margin and a trunk channel along the trough axis. Voluminous debris flows were generated ubiquitously along the tract of the submarine channel mainly by the failure of nearby channel banks or slopes. The flows transformed immediately into multiphase flows and resulted in very thick-bedded mass-flow deposits with a peculiar structure sequence. The mass-flow deposits commonly overlie fluted or grooved surfaces and consist of a lower division of clast-supported and imbricated pebble-cobble conglomerate with common basal inverse grading, and an upper division of clast- to matrix-supported and disorganized pebble conglomerate or pebbly mudstone with abundant intraformational clasts. The structure sequence suggests a temporal succession of a turbidity current, a bipartite hyperconcentrapted flow with active clast collisions near the flow base, and a cohesive debris flow probably with a rigid plug. The multiphase flow is interpreted to have resulted from transformation of clast-rich but cohesive debris flows. Cohesive debris flows appear to transform more easily into dilute flow types in subaqueous environments because they are apt to hydroplane. This is in contrast to the flow transitions in subaerial environments where noncohesive debris flows are dominant and difficult to hydroplane.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.4
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• pp.84-90
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• 2011

In active noise control filter, LMS algorithms which used for control filter, assure the convergence property, and computational burden of these algorithms are proportionate to the filter taps. The convergence speed of LMS algorithms is mainly determined by value of the convergence coefficient, so optimal selection of the value of convergence coefficient is very important. In this paper, We proposed novel adaptive fuzzy logic LMS algorithms with FIR filter structure which has better convergence speed and less computational burden than conventional LMS algorithms, for single channel active noise control with ill conditioned signal case. Computer simulations were performed to show the effectiveness of a proposed algorithms.