• Journal of the Institute of Convergence Signal Processing
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• v.19 no.4
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• pp.167-173
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• 2018

We propose an air purification system that utilizes aerial plant parts and root zone of indoor plants where light is insufficient and air circulation is bad. In order to maximize the air purification effect of the plant, the aerial plant parts illuminates mixed light combining blue and green LED and CRI(Color Rendering Index) LEDs close to natural light, respectively. And the root zone was forcibly circulated by the fan to use the soil as a filter. The indoor air purification system combined with the light source and the fan removed most polluted air in the shortest. In the case of mixed light and CRI LEDs of indoor air purification system, fine dust decreased by 14%, 14.2%, and TVOC(Total volatile organic compounds) decreased by 7.5% and 9.4%, respectively. In the experiment in which the fan was operated for 15 minutes, the TVOC decreased to 97.8%. The photosynthesis of the plant and the use of soil as a filter were able to purify polluted air in a short time. And the fan's temporary operation gave the similar effect of continuous operation.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.453-455
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• 1995

In electrostatic airclean filter, the collection efficiency defends on particle charge in the ionizer section. The effect of electrostatic airclean filter condition (deposition of dust, variation of corona discharge current) on corona discharge characteristics was well studied. However, it seems not to be studied on corona discharge characteristics of electrostatic airclean filter respect to contaminated electrode which is caused by practical use. In this paper, Long-term(60days) effects are studied experimentally by two methods. The one is ozone concentration, the other is collection efficiency. Generation of ozone level was increased but collection efficiency was slightly reduced in long-term used electrostatic airclean filter.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.386-388
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• 2007

In many applications of UAVs flying in low altitude, the steady supply of accurate height measurements is very important for the UAVs to complete their mission successfully. In order to do this, a barometer or GPS height measurements are widely used. However, because these two sensors have their limitations in the application environment, a method for fusing these two measurements to produce reference heights are required. In this paper, a reference height generation filter is designed for UAV(Unmanned Air Vehicle) applications. The barometer errors originated by the change of the atmospheric environment are modeled using random walk models, and then the errors are identified and compensated through the ZSB(zero-scan-back) filter algorithm using the GPS height measurements. The performance of the proposed filter is demonstrated by realistic simulations.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.4 no.2
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• pp.172-175
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• 2004

Generally, the yield rate of semiconductors is the major factor that affects directly the price of semiconductors. For a high yield rate of semiconductors, the air inside clean room is needed to be purified and high efficient filters are used for this. The filter are made of super-fine fiber and certain pinholes can be easily produced on the filter's surface by inadvertent manufacturing. As these pinholes are not easily detected with the bare sight, these pinholes exert a negative impact to filtration performance of the filter. In this research, not only the automatic test equipment for detecting pinholes is proposed, but also inverse modeling scheme based on artificial neural network is applied for tuning of its important parameters.

• Membrane Journal
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• v.33 no.6
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• pp.398-408
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• 2023

This work developed a hood and filter for antibacterial protective clothing for medical powered air purifying respirators (PAPR) that can be used in medical settings and quarantine against infectious diseases such as Zika virus, Middle East respiratory syndrome (MERS), and coronavirus disease-19 (COVID-19). The hood material of the protective clothing was made of polypropylene spunlace nonwoven fabric (SFS) was used for withstand wind pressure and external physcial pressure. Forthermore, in order to reduce the user's risk of infection, phytoncide-based materials were used on the outer-surface of the hood to achieve a 99.9% antibacterial effect, and the inner-surface were treated with hydro-philic materials to improve absorbency by 25%. In addition to evaluating the artificial blood penetration resistance, dry mi-croorganism penetration resistance, wet bacteria penetration resistance, and bacteriophage penetration resistance required for medical protective clothing hoods, it received a passing evaluation of levels 2-6. Meanwhile, as a result of evaluating the performance of the antibacterial treated spunlace high efficiency particulate air (HEPA) filter, excellent antibacterial properties, dust removal rate, and differential pressure effect were confirmed. All performance evaluations were conducted by an accredited certification body in accordance with the medical PAPR certification standards.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.95-98
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• 2006

Filtration by fibrous filter is one of the Principle methods used for removing pollutant particles in the liquid. Because of the increasing need to protect both human health and valuable devices from exposure to fine particles, filtration has become more important. Filters have been developed with modified surface charge characteristics to capture and adsorb particles by electrokinetic interaction between the filter surface and particles contained in water. The main purposes of this study are to develop and evaluate the performance evaluation of the apparatus for making a positively charged porous filter media and to analyze the surface characteristics of the filter media for capturing negavitely charged contaminants mainly bacteria and virus from water. The experimental apparatus consists of a mixing tank, a vacuum pumping system, a injection nozzle, a roller press and a controller. The filter media is composed of glass fiber(50-750 nm), cellulose($10-20{\mu}m$) and colloidal charge modifier. The characteristics of filter media is analyzed by SEM(Scanning Electron Microscopy), AFM(Atomic Force Microscopy) and quantified by measuring the zeta potential values.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1830-1837
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• 2023

The thermal cutting of contaminated or activated metals during decommissioning nuclear power plants inevitably results in the release of radioactive aerosol. Since radioactive aerosols are pernicious particles that contribute to the internal dose of workers, air conditioning units with a HEPA filter are used to remove radioactive aerosols. However, a HEPA filter cannot be used permanently. This study evaluates the efficiency and lifetime of filters in actual metal cutting condition using a plasma arc cutter and a high-resolution aerosol detector. The number concentration and size distribution of aerosols from 6 nm to 10 ㎛ were measured on both the upstream and downstream sides of the filter. The total aerosol removal efficiency of HEPA filter satisfies the standard of removing at least 99.97% of 0.3 ㎛ airborne particles, even if the pressure drop increases due to dust feeding load. The pressure drop and particle size removal efficiency at 0.3 ㎛ of the HEPA filter were found to increase with repeated cutting experiments. By contrast, the efficiency of used HEPA filter reduced in removing nano-sized aerosols by up to 79.26%. Altogether, these results can be used to determine the performance guidance and replacement frequency of HEPA filters used in nuclear power plants.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.11a
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• pp.112-113
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• 2004

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2009.10a
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• pp.133-134
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• 2009

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.04a
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• pp.327-328
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• 1999