• Journal of the Institute of Convergence Signal Processing
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• v.13 no.2
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• pp.63-69
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• 2012

Noise is regarded as an unwanted component of the image because it significantly reduces image quality. And image is often corrupted by mixed noise. In this paper an efficient modified weighted filter algorithm which combines spatial weight and intensity weight is proposed for removing mixed noise. In the proposed method, the filtering mask is separated into the four sub-windows and the parameters of the weights are confirmed by calculating local standard deviation and the mean of four sub-windows' standard deviations. Considering the spatial information and intensity information, the proposed method has good performance on not only noise elimination but also preservation of details. Simulation results demonstrate that the proposed method performs better than conventional algorithms.

• Journal of the Korean Society of Tobacco Science
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• v.27 no.2
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• pp.163-170
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• 2005

A theoretical model for predicting the capability curve of cellulose acetate filter is derived. The pressure drop is expressed as a function of the filter dimensions, the tow fiber characteristics, the filter weight, the fluid flow rate, and a filter fiber factor. Where, the filter fiber factor is affected by the distribution of the tow fibers within the filter, the relative orientations of the tow fibers, and their cross-sectional shapes. The minimum and maximum fraction of solids in capability curves determined from experimental data. Also, the filter fiber factor is expressed as a function of the filter length, tow fiber length, and tow fiber diameter. Capability curves predicted by the suggested model in this work correspond well with capability curves by experimental data.

• Journal of Sensor Science and Technology
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• v.25 no.1
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• pp.8-12
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• 2016

A planar, light-weight, and low-cost notch filter structure is required for the KSTAR ECEI (Electron Cyclotron Emission Imaging) system to protect the mixer arrays from spurious plasma heating power. Without protection, this heating power can significantly degrade or damage the performance of the mixer array. To protect mixer arrays, a frequency selective surface (FSS) structure is the suitable choice as a notch filter to reject the spurious heating power. The FSS notch filter should be located between the lenses of the ECEI system. This paper presents a 170 GHz FSS notch filter for the KSTAR ECEI sensor application. The design of such an FSS notch filter is based on the single-sided square loop geometry, because that makes it relatively insensitive to the incident angle of incoming wave. The FSS notch filter exhibits high notch rejection with low pass-band insertion loss over a wide range of incident angles. This paper also reviews the simulated and measured results. The proposed FSS notch filter might be implemented in other millimeter-wave plasma devices.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.3
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• pp.238-243
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• 2010

A new implementation method for MPDSAP(Maximally Polyphase Decomposed Subband Affine Projection) adaptive filter is proposed. The affine projection(AP) adaptive filter achieves fast convergence speed, however, its implementation is so expensive because of the matrix inversion for a weight-updating of adaptive filter. The maximally polyphase decomposed subband filtering allows the AP adaptive filter to avoid the matrix inversion, moreover, by using a pipelining technique, the simple subband structured AP is suitable for VLSI implementations concerning throughput, power dissipation and area. Computer simulations are presented to verify the performance of the proposed algorithm.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.4
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• pp.84-91
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• 1996

Input filter for satellite communication transponder is the interface between the antenna and the receiver. It is used to provide the selection of the uplink signals with minimum insertion loss and to prevent downlink signals form reaching the LNA. This paper is intended to provide a description of the input filter for KOREASAT communication transponder. Included are description for the electrical and mechanical design and the requirments of environmental test. In expecting the electrical performine the optimum electrical configuration ot meet all requirements are performed. Mechanical requirements are charactersed by several constraints for weight, size of the filter and its type of input output interface. The standardized environmental tests are performed to confirm satisfactory performance of the filter with respect to the requirements of vibration and thermal vacuum shocks.

• Journal of the Korean Society of Tobacco Science
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• v.23 no.1
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• pp.77-81
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• 2001

This study was conducted to determine menthol migration from the tobacco to the filter and the change in percentage of menthol in pack for different mentholated cigarettes. Methanol was used to extract menthol from tobacco, filter and foil. A known weight of internal standard was added to each extract and then the extracts were analyzed by gas chromatography. After 4 days, 95% of the menthol applied to the foil was delivered into the tobacco and filter, but in case of menthol applied to the tobacco, the percentage of menthol that migrated from the tobacco to the filter was below 10%. After 100 days, 30-45% of the menthol in the tobacco had migrated into the filter. The amount of menthol in the pack decreased after 20 days of storage, however, the remaining menthol in cigarette treated with 0.30% propylene glycol was higher in amount than that with 0.12% propylene glycol In analysis on menthol transfer to mainstream smoke, the most efficient sample was the cigarette with menthol applied to the foil rather than to the tobacco.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.164-167
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• 2003

In this study, we developed the mold for the plastic cavity filter which is a kind of a wireless communication device. Since the cavity filter is made of aluminium, the cost of fabrication is high and the production rate is low. But we can produce plastic cavity filter part by injection molding process with the mold which was designed by our team. The dimension and surface quality of plastic cavity filter was investigated by varying the molding method (conventional and MmSH process) and two different types of resin(PC/ABS and ABS). In case of ABS part, the shrinkage of the inner partition walls was decreased when we adopted MmSH method. The weight of both ABS and PC/ABS parts increased and the surface roughness decreased with MmSH process.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.1
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• pp.121-128
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• 2009

Objectives of this study were to investigate influencing factors of detention time, particle size distribution, and filter medium characteristics for waterworks sludge dewatering. The stepped pressure filtration was carried out with lab scale apparatus and the filter press pilot test for dewatering was conducted at the water treatment plant. Effects of filter medium and polymer dose were examined through observing water content and dewatering velocity and cyclic dewatering rate with filter press pilot test. Relationships among detention time, particle size distribution and filtration resistance were analyzed. Prolongation of sludge detention time was found to cause blinding phenomenon in cake and filter medium and to decrease dewatering process efficiency. The average specific resistance increased according to detention time. In pilot test of dewatering for thickened sludge with Nylon Multi-NY840D and Nylon Mono-100% filter media, dewatering velocities were 0.92 and $0.93kg\;DS/m^2{\cdot}hr$ according to 0.1% polymer dose of dried solids weight base. And cyclic dewatering rates were 2.45 and $2.50kg\;DS/m^2{\cdot}cycle$ cycle for the Nylon Multi-NY840D and Nylon Mono-100% media. Dewatering velocity of polymer dosed sludge was observed to be higher than that of non-polymer sludge.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.118-120
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• 2021

In modern society, with the development of IoT technology, various digital equipment is being distributed in a wide range of fields such as CCTV and exploration robots. Accordingly, the importance of data processing is increasing, and various studies are being conducted to remove noise generated in the process of receiving data in the imaging field. Representative noise includes additive white Gaussian noise (AWGN), and existing filters for removing noise include an average filter (AF), an alpha trimmed average filter (A-TAF), and a median filter (MF). However, existing filters have a disadvantage in that they show somewhat insufficient performance in noise removal characteristics in high frequency areas. Therefore, in this paper, in order to effectively remove AWGN existing in the high frequency region, a weight filter according to a distance based on the standard deviation is proposed.

• Korean Journal of Plant Resources
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• v.33 no.1
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• pp.33-39
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• 2020

This study was carried out to provide basic information for mass breeding and cultivating the saplings of Camellia japonica. The germination rates did not show definite tendency according to the changes of seed weight at room temperature and 4℃ dry storage conditions. The germination rate of 4℃ wet sand storage was increased with seed weight, but showed very low germination rate for 120 days of storage. The germination rate was above 80% in 60 days, 90 days and 120 days, respectively, at 4℃ wet filter paper storage conditions. The average days taken for those germinations were about 30 days at room temperature and 4℃ dry storage conditions, but wet storage (sand, filter paper) condition took the shortly nearly 13 days for those germinations. Leaf number, leaf dry weight, stem diameter and root dry weight were higher than total average by more than 1.21 g for seed weight. Stem length was higher than the average by more than 1.01 g, plant dry weight was higher than the average by more than 0.81 g, and stem dry weight was higher than the average by more than 0.61 g. In the case of seed weight becoming heavier, seedling growth was good but T/R ratio tended to decrease. In order to increase the mass production of seedlings using Camellia japonica seeds, we need to specify the weight and size of those seeds. The 4℃ wet filter paper storage condition was evaluated as the most efficient method for the seed storage used for seeding.