• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.194-202
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• 2009

The paper deals with the countermeasure against structure-borne noise source and noise reduction of drainage pipes. Recently, the problem the problem of the toilet drain noise of an apartment house has been become the center of public interest and a target of public grievance. Generally, the drain noise of a toilet in the apartment house has a pink noise characteristics below 2 kHz level, and therefore, the structure-borne noise has a great effect on the entire drain noise. In order to measure the transmission loss for various kinds of pipes such as PVC pipes, cast-iron pipes and newly developed AS pipes, experimental setup containing speakers as a sound source was designed and manufactured. The second-stories measurement room with a small size anechoic chamber was constructed and the noise level for different kinds of drainage pipes was measured by the sound level meter. Through the experimental research in the study, noise reduction capacity for various kinds of drainage pipes and countermeasures against structure-borne noise source are demonstrated.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06a
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• pp.716-721
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• 1994

The goal of this study is to develop treatment methods for improving the noise quality of Home Appliance Drain Pumps. Developed treatment methods covers the various methods including the control of the water level through the developed electronic circuity and the various modifications over the design of impeller and fan units. In the first part of the studies Dominant noise sources of the pumps are analyzed. Specific noise problems of the pumps are classified on the basis of mechanic and magnetic origins. Factors including the pressure variations at suction head, magnetic interactions with structure, specific fan noises are studied sequentially. The second part of the studies are considered for development and application of treatment methods. Results denoted the basic problems and ways to improve the noise quality by treating the dominant soureces of drain pumps.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.8
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• pp.1263-1268
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• 2008

In this paper, the low noise power amplifier for GaAs FET ATF-10136 is designed and fabricated with active bias circuit and self bias circuit. To supply most suitable voltage and current, active bias circuit is designed. Active biasing offers the advantage that variations in the pinch-off voltage($V_p$) and saturated drain current($I_{DSS}$) will not necessitate a change in either the source or drain resistor value for a given bias condition. The active bias network automatically sets a gate-source voltage($V_{gs}$) for the desired drain voltage and drain current. Using resistive decoupling circuits, a signal at low frequency is dissipated by a resistor. This design method increases the stability of the LNA, suitable for input stage matching and gate source bias. The LNA is fabricated on FR-4 substrate with active and self bias circuit, and integrated in aluminum housing. As a results, the characteristics of the active and self bias circuit LNA implemented more than 13 dB and 14 dB in gain, lower than 1 dB and 1.1 dB in noise figure, 1.7 and 1.8 input VSWR at normalized frequency $1.4{\sim}1.6$, respectively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.923-927
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• 2003

The aim of this study is to investigate the characteristics and quantity of the noise reduction by pipe material, wrapped pipe with glass wool and installed pipe height The characteristics of noise emission from drain-pipes is as follows. The noise reduction pipe in PVC can reduce noise levels in 7-10㏈ and the cast-iron pipe can reduce in 14㏈compared with the normal PVC pipe. In these days, the glass wool was used for preventing the burst and the noise reduction. But the glass wool for wrapping pipe is not effective to the noise reduction. The characteristics of noise emission from various installed pipe height were measured As the ceiling space of the remodeled building was raised, the noise level was troubled by increasing of the vertical pipe length.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10A
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• pp.1579-1587
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• 1999

Bias-dependent noise models of $0.2\mu\textrm{m}$ gate length P-HEMT's which are scalable with gate width are proposed. To predict S-parameters of the P-HEMT's the intrinsic parameters except for $\tau$ subtracted the offsets introduced in this paper are normalized to the gate width and then scaled. The small-signal model parameters are expressed as fitting functions of the drain current to $\textrm{I}_{dss}$ ratio and gate width. In addition, to estimate accurately noise parameters the noise temperature $\textrm{T}_{g}$ of the intrinsic resistance, the equivalent noise conductance $\textrm{G}_{ni}$ of the gate current noise source, and the equivalent noise conductance $\textrm{G}_{no}$ of the drain current noise source are adopted as the noise model parameters. The extracted values of $\textrm{T}_{g}$ are nearly independent of drain current and gate width and their average is around the ambient temperature. The extracted values of $\textrm{G}_{ni}$ are small enough to be neglected to the circuit characteristics. From the comparison of the noise model with only $\textrm{G}_{no}$ and that having $\textrm{T}_{g}$, $\textrm{G}_{ni}$ and $\textrm{G}_{no}$ to the measured data it is fund that even the former model is in good agreement with the measured noise parameters. Thus, from a practical point of view the noise model having only the drain current noise source is confirmed as a scalable bias-dependent model.

• KIEAE Journal
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• v.1 no.2
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• pp.13-19
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• 2001

Recently, With the increase of income level, many people desire to have agreeable and quiet surrounding. However, the extent and time of the exposure to construction noise and vibration is increasing, which is a factor that ruins the quietness of the surrounding and increasingly raises interests in its effects. In this point, this study attempts to survey the characteristics of construction vibration by SD(Sand drain) method in construction field. In addition, the result of study is presumed to be usable as the fundamental materials for an efficient counter-plan in case of the public resentment in relations to the construction vibration occurring henceforth.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1459-1462
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• 2005

The paper deals with the structural vibration and noise characteristics of pipe structures. In general, A structure bone noise has a great effect on the drain noise of toilets, and depends on the natural frequency of the related structures. In order to measure and to find the relationships between structural vibration and noise of the pipe structures, some experiments have been performed. Through the experiments, impact acceleration signal in time domain and magnitude of transfer function in the frequency domain have been investigated for three kinds of pipes. Transmission loss of pipes depending on the frequency ranges was also found by using small speakers as a sound source.

• Journal of the Semiconductor & Display Technology
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• v.19 no.3
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• pp.82-87
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• 2020

The comprehensive and physics-based compact noise models for advanced CMOS devices were presented. The models incorporate important physical effects in nanoscale MOSFETs, such as the low frequency correlation effect between the drain and the gate, the trap-related phenomena, and QM (quantum mechanical) effects in the inversion layer. The drain current noise model was improved by including the tunneling assisted-thermally activated process, the realistic trap distribution, the parasitic resistance, and mobility degradation. The expression of correlation coefficient was analytically described, enabling the overall noise performance to be evaluated. With the consideration of QM effects, the comprehensive low frequency noise performance was simulated over the entire bias range.

• KIEAE Journal
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• v.4 no.3
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• pp.37-44
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• 2004

In this study, foreign and domestic noise criteria on walls, floors, and water supply facilities were reviewed and the results are as follows : regulation can be divided two things, one is on thickness the other is sound insulation performance. Green Building regulation based on the law and this have sound classification systems. Since these regulations are not established in Korea. The noise regulation on water supply-drain facilities and domestic guideline on interior noise level is needed. Foreign regulations are stricter than those of ours. And those has sound classification system for the better acoustic condition of inhabitants'.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.644-645
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• 2014