• Steel and Composite Structures
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• v.19 no.4
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• pp.939-952
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• 2015

In this paper, brake pad performance of two organic matrix composites namely, Sample 1 (contains no brass filler) and Sample 2 (contains 1.5% brass filler), is studied based on tribological and squeal noise behavior. In the first stage, a pin-on-disc tribometer is used to evaluate the frictional behavior of the two pads. On the following stage, these pads are tested on squeal noise occurrence using a drag-type brake dynamometer. From the two type of tests, the results show that; (i) brass fillers play a dual role; firstly as reinforcing element of the brake pad providing primary contact sites, and secondly as solid lubricant by contributing to the formation of a layer of granular material providing velocity accommodation between the pad and the disc; (ii) brass fillers contribute to friction force stabilization and smooth sliding behavior; (iii) the presence of small weight quantity of brass filler strongly contributes to squeal occurrences; (iv) there is close correlation between pin-on-disc tribometer and brake dynamometer tests in terms of tribological aspect.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.5
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• pp.106-115
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• 1996

This study was carried out to provide fundamental data for reuse of resources and prevention of environmental pollution Actual states of environmental pollution by biological production facilities were investigated. Various pollution loads and quantity of wastes from greenhouse and animal housings estimated. In greenhouse contents of investigation were wastes of plastic cover, noise of heater and fan, air pollutant of heater, and wastes of soilless culture system, etc. In animal housings, those were actual state of livestock waste treatment and reuse, pollutant mass unit discharge, noise pollution, and malodorant, etc. The main pollutants discharged from greenhouses were wastes of plastic cover, rockwool, and waste fluid of nutrient solution. Developments of waste disposal methods for plastic cover and rockwool are required. And recycle technique of nutrient solution for soilless culture should be developed and propagated. With the buildup of legal control, pollutant mass discharged from livestock wastes are, on the decrease. The other side, reuse of livestock excreta increased. Most animal housings are located near the dwelling house. Malodorant and noise from animal housings have bad effects on the rural living conditions. So developments of integrated complex for small scale livestock farms are required.

• Journal of KSNVE
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• v.8 no.5
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• pp.841-848
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• 1998

In the gear manufacturing, tooth modification is usually applied for the prevention of tooth impact during the loading. In contrary, tooth profile error causes amplifying the whine noise which is cumbersome to reduce in the automobile gear box. So optimum quantity of the modifications must be obtained for the good performance in the vibrational sense. In this paper, a formulation to define the tooth curve by considering the profile manufacturing error and loading deformation of the gear tooth is suggested and the transmission error and loading deformation of the gear tooth is suggested and the transmission error with modified tooth in the gear system is evaluated. A pair of gear set is mathematically modelled. The equivalent excitation in the gear vibratonal model is formulated. For the experimental evaluaton on the derived transmission error function, a simple geared system is set up in which the gears are designed to give pre-designed tooth profile modification and manufactured by CNC Wire Cutting Machine. Under slow speed operaton, the transmission error of the gear pair is measured by using two rotational laser vibrometers, compared with the calculated one of which the result shows good agreement.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.6
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• pp.96-103
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• 2009

Wind power, Solar power and Fuel cell is the representative of new and renewal energy sources. In this paper, the frictional noise made by vehicles tire on roads is considered and researched as alternative electrical generation source. The amplitude and waveform of generated electricity with various types of vehicles according to their velocity, weight and distances between vehicles and sensor are measured and analyzed. As a result, all difference effects mentioned above which make the frictional noise affect quality and quantity of generated electricity. Maximum 0.53[V] and 0.028[W] electricity was generated by truck with 100[km/h] velocity on the express way.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.6
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• pp.1122-1128
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• 2007

The denoising for image restoration based on the Wavelet Packet Transform with AA(Absolute Average) making-threshold is presented. The wavelet packet transform leads to be better in the part of high frequency than wavelet transform to eliminate noise. And the existing threshold determination is used standard deviation estimated results in increasing the noise and threshold, and damaging an image quality. In addition that is decreased image restoration PSNR by using the same threshold in spite of changing image because of installing a threshold in proportion of noise size. In contrast the AA thresholding method with wavelet packet is adapted by changing image to set up threshold by statistic quantity of resolved image and is avoided an extreme impact. The results on the experiment has improved 10% and 5% over than the denoising based on simple wavelet transform and wavelet packet respectively.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.485-490
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• 2004

Recently, distribution transfer velocity was extremely lowered by high supply rate of vehicle and low road rate. Therefore expansions of transfer network these were subway, road and railway to recover competitive power as a reform measure of physical distribution traffic were become preference previous subject. For reason of that, an expansion of transfer network is meeting competitive power as selected an elevated road in the ground road network that condition of location calm and get out of the existing urban than the underground road to connect oversensitive a large city and expanded small and medium satellite town. In the meantime, while elevated structures construct, they go through the civilian residential section, agriculture land, etc. The consequence is that it raises a vibration, noise, dust, an infringement of the right to a view and an infringement of the right to a sunshine. In this study, we analyzed Quantitatively sunshine quantity with building 3D simulation model of civil structure. Therefore, we present as planning data to reduce a civilian appeal for dispute of the right to sunshine and an economic and time loss between the government and construction company In addition to that, for the standard of the standard plan of usable sunshine quantity program in the practical business, the building of convenient user interface will be the project to be done.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.3
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• pp.36-40
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• 2002

In this paper, we proposed a digital watermarking method based on the edge-wavelet transform to protect digital contents copyrights. We find out the optimal watermark insertion region and the proper amount of watermark in order to satisfy robustness and imperceptibility against various attacks such as noise, compression, collusion, clipping, scaling. Especially through this experiment, we could find out the adequate location of watermark insertion and proper amount of watermark and it is also viewed to satisfy robustness and imperceptibility in the lower frequency region with small watermark quantity.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.377-380
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• 2002

When it calculates the optimum price of filter coefficient, the many operation quantity is necessary. Is like that the real-time control is difficult and the hardware embodiment expense is big. The case which does not know advance information of input signal or the case where the statistical nature changes with change of surroundings environment is necessary the adaptive filter. Every hour to change a coefficient automatically and system in order to reach to the condition of optimum oneself, the fact that is the adaptive filter. When it does not the quality of input signal or it does not know the environment of surroundings every hour changing, it does not emit not to be, in order to collect, the fact that is the adaptive filter. The case of the Acoustic Echo Canceler does thousands filter coefficients in necessity. It reduces a many calculation quantity to respect, it uses the IIR filter from hour territory. Also it uses the block adaptive filter which has a block input signal and a block output signal. The former there is a weak point where the stability discrimination is always demanded. Consequently, The block adaptive filter is researched plentifully. This dissertation planned the block MADF adaptive filter used to MADf algorithm.

• KIEAE Journal
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• v.10 no.3
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• pp.51-56
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• 2010

The sound insulation performance is one of the important factor that determined the amenity of housing life in residential building. Especially, Apartment house represents a korea habitation. So the importance of privacy and noise problems between habitable rooms are emphasized in these habitation. This study investigates and find a problem of sound insulation performance of partition wall of the apartment house in current state. The measurements were carried out in apartment house with and without a stair hall. And the measurements also carried out in current state and installing a sound absorbing material in receiving room and changing a front door and installing a inner door. In spite of the same partition wall, difference results were showed according to the stair hall. It is appeared that sound insulation performance without stair hall is 6-7dB(Dw) higher than that with stair hall. In case of without stair hall, sound insulation performance is Dw 49 for single number quantity for airbone sound. And In case of changing a front door and installing a inner door sound insulation performance is Dw 57 for single number quantity for airbone sound. The Results of measuring on the changes a front door and installed a inner door indicated that the flanking sound through front door influenced the sound insulation performance.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.4 s.304
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• pp.127-132
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• 2005

The curve of motion indicated to waveform of the fast movement of human extracted using virtual reality or the quantity of time fluctuation of the electromagnetic signal as the quantity of electric fluctuation of the atmosphere is complex. It is important to decide exactly the signal property as the inflection point for the observation signal. When the signal is mixed by noise signal, the traditional method is difficult to detect the inflection point. In this paper the noisy signal is eliminated by wavelet thresholding method and the filter using natural observation theorem is applied. It shows that the inflection point of the signal waveform can be detected exactly.