• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.2
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• pp.99-104
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• 2013

Assessment of noise exposed population is to check the environmental noise level and social influence in order to reduce the risks such as annoyance and disturbance that are generated by environmental noise. Also, this method suggests the preferential noise abatement policy and action plan by accurately finding the area that the noise causes harmful effect to human health. Recently, a noise map, which can predict noise in comprehensive areas, is used for the assessment of noise exposed population, breaking from the methods using existing measures. In particular, countermeasure for the noise can be considered more effectively by using assessment methods of noise exposed population for specific noise levels, areas, and building types which are the main input factors in noise maps. In this study, assessment methods of noise exposed population by using 2 dimensional noise map are compared with those by 3 dimensional noise map.

• Journal of the Institute of Convergence Signal Processing
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• v.20 no.3
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• pp.165-170
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• 2019

Recently, modern society has come up with the importance of video processing as various imaging systems have developed. However, deterioration occurs in the process of transmitting, processing, and storing video data for various reasons. Deterioration will damage the original image, and the typical noise is Salt and Pepper noise. There are A-TMF, CWMF, and linear interpolation as the means to eliminate Salt and Pepper noise. However, these methods show somewhat poor noise abatement performance in high-density noise areas. Therefore, this paper proposes an algorithm to eliminate noise using modified linear interpolation. To prove the validity of the proposed algorithm, PSNR, Profile was used to compare it with existing methods.

• Safety and Health at Work
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• v.15 no.3
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• pp.327-337
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• 2024

Background: As the tremendous impact of extreme workloads, arduous working conditions, and disorganization disrupt humane job definitions in some industries, the need for workplace re-articulation was interfered to ameliorate psycho-social factors and suggest organizational intervention strategies. Especially for colossally wounded health-care (HC) systems, today it is now even more unrealizable to retain workforce resilience considering the immense impact of overwhelming working conditions. Methods: This study introduces employment of concurrent engineering tools to re-design humane workplaces annihilating abatement over devoured resources. The study handles HC-workforce resilience in a pioneering motive to introduce transformation of well-known motivators and proposes solutions for retention and resilience issues grounding on HC workers' own voice. Results: The proposed adjustable approach introduces integral use of focus group studies, SWARA, and QFD methods, and was practiced on a real-world case regarding Turkish HC workforce. The paper also presents widespread effects of findings by tendering generalized psycho-social rehabilitation strategies. Results confirmed the modifications of the most potent incessant motivators. Conclusion: "Burn out issues" and "Challenging work" were found as the most important motivator and satisfier, respectively, to be exigently fulfilled. Corrective interventions, required resolutions, and workplace articulation connotations were arbitrated in terms of entire outcomes on four dimensions in three different planning periods considering the current status, repercussions of pandemic, and contingency of similar catastrophes. Descriptive illustrations were additionally presented to support deducted interpretations.

• KIEAE Journal
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• v.1 no.2
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• pp.21-28
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• 2001

Naturally-ocurring short-lived decay products of radon gas in indoor air are the dominant source of ionizing radiation exposure to the general public. It is written in BEIR VI Report(l999l the radon progeny were identified as the second cause of lung cancer next to cigarette or 10 % to 14 %(15,400 to 21,800 persons p.a.) of all lung cancer deaths in USA. Indoor radon concentrations in houses typically result from radon gaining access to houses mainly from the underlying soil. In the States, they have "Indoor Radon Abatement Act" which was converted from "Toxic Substance Control Act" in 1988 to establish the national long-term goal that indoor air should be as free of radon as the ambient air outside of buildings. To review and study techniques for controlling radon, two test cells were constructed for a series of tests and are under measuring indoor and soil gas (underneath of floor slab)radon concentrations according to EPA's measurement protocol. In this paper, important theoretical studies are previewed and the following paper will explain the test results and confirm the theories reviewed to find out suitable coefficients. On the basis of test analysis, it will be described and evaluated various techniques that can be used to mitigate elevated indoor concentration of radon including the control of radon and its decay products.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.1
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• pp.1-7
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• 2004

This study has been numerically conducted to investigate the removal efficiency of Volatile Organic Compound (VOC) for different photocatalytic honeycomb filters. Recently, the photocatalysis is being applied to air-cleaner, air-conditioner and vacuum-cleaner with the capability of air-purification, sterilization and antibiosis. However, photocatalysis is less efficient than other methods for removing VOC except in the case of low concentration. So far most of studies have focused on an improvement of the photocatalytic materials, but this study have placed emphasis on the improvements of shape of photocatalytic honeycomb filter. UV irradiation, concentration profile and pressure drop have been investigated for different cross sections of filters and for different filter lengths. Light intensity is dropped sharply with increasing distance from the UV-lamp, and becomes very low in the middle of the filters. Since photocatalytic reaction rate is a function of light intensity, VOC concentration gradient might be small in the middle of long filters. Thus, most of reaction have risen within only three times of dimensionless axial distance. These results can be used effectively for the design of advanced photocatalytic honeycomb filters.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.4
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• pp.525-529
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• 2016

Biomass co-firing to existing thermal power plants is one of the most economical and efficient way to reduce $CO_2$ emission from the plant. There are several methods of co-firing and it can be categorized into (1) Parallel co-firing, (2) Indirect co-firing, and (3) Direct co-firing. Parallel co-firing is the most expensive way to high-ratio co-firing because it requires biomass dedicated boiler. Direct co-firing is widely used because it does not need high capital cost compared with the other two methods. Regarding the direct co-firing, it can be classified into three methods- Method 1 does not need retrofit of the facilities because it uses existing coal mills for pulverizing biomass fuels. In this case high-ratio co-firing cannot be achieved because of poor grindability of biomass fuels. Method 2 needs biomass-dedicated mills and revision of fuel streams for the combustion system, and Method 3 needs additional retrofit of the boiler as well as biomass mills. It can achieve highest share of the biomass co-firing compared with other two methods. In Korea, many coal power plants have been adopting Method 1 for coping with RPS(Renewable portfolio standards). Higher co-firing ratio (> 5% thermal share) has not been considered in Korean power plants due to policy of limitation in biomass co-firing for securing REC(Renewable Energy Certificate). On the other hand, higher-share co-firing of biomass is widely used in Europe and US using biomass dedicated mills, following their policy to enhance utilization of renewable energy in those countries. Technical problems which can be caused by increasing share of the biomass in coal power plants are summarized and discussed in this report. $CO_2$ abatement will become more and more critical issues for coal power plants since Paris agreement(2015) and demand of higher share of biomass in the coal power plants will be rapidly increased in Korea as well. Torrefaction of the biomass can be one of the best options because torrefied biomass has higher heating value and grindability than other biomass fuels. Perspective of the biomass torrefaction for co-firing is discussed, and economic feasibility of biomass torrefaction will be crucial for implementation of this technology.

• International Journal of Highway Engineering
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• v.18 no.5
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• pp.31-37
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• 2016

PURPOSES : The purpose of this study is to evaluate the effect of the quiet pavement on reducing a barrier height by using a prediction tool called SoundPLAN. METHODS : Firstly, the prediction was carried out to evaluate the difference in the maximum noise level at a building facade between the normal and the quiet pavements without a barrier. After calculating the noise reduction effect by the quiet pavement, a comparable barrier height to obtain the same noise reduction effect with it was predicted according to designable factors including road-building distance(10 m, 20 m, 40 m) and road-barrier distance(5 m, 10 m, 20 m, 30 m). RESULTS : The result showed that within the considered designable factors, the maximum barrier height was 37 m, 52 m, and 55 m to have the same noise reduction effect by the quiet pavement reducing 1 dBA, 3 dBA, and 5 dBA, respectively. It was evaluated that the barrier height increased with the increase of the road-building and road-barrier distances. To simulate the real situation in urban areas and to evaluate the combined effect of the normal/quiet pavement and barrier, the barrier height was fixed as 6 m. It was predicted that the noise level would reduce to as low as 0.2 dBA by the combination of normal pavement and barrier. On the other hand, the combination of the quiet pavement and barrier reduced 1.2 dBA, 3.2 dBA, and 5.2 dBA, respectively, for quiet pavement reducing 1 dBA, 3 dBA, and 5 dBA. CONCLUSIONS : A guideline needs to be suggested to select appropriate noise abatement schemes by considering factors such as the roadbuilding and road-barrier distances.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.7
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• pp.1209-1216
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• 2020

Objective: The present study aimed to evaluate the performance of odor abatement by using two different ventilation-biofilter systems with recycled stablized swine wastewater. Methods: The performance of odor removal efficiency was evaluated using two different ventilation-biofilter-recycled wastewater arrangements. A recirculating air-flow ventilation system connected to a vertical biofilter (M1) and a plug-flow ventilation system connected to a horizontal biofilter (M2) were installed. Water dripping over the surface of the biofilter was recycled at a flow rate of 0.83 L/h in summer and 0.58 L/h in winter to reduce odorous compounds and particulate matter (PM). The experiments were performed for 64 days with M1 and M2 to investigate how these two ventilation-biofilter systems influenced the reduction of odor compounds in the model houses. Odorous compounds, NH₃ and volatile organic compounds (VOCs) were analyzed, and microclimatic variables such as temperature, humidity, and PM were monitored. Results: Ammonia concentration inside M1 was about 41% higher on average than that in M2. PM and total suspended particles (TSPs) inside M1 were about 62.2% and 69.9%, respectively, higher than those in M2. TSPs in the model house were positively correlated with the concentration of NH₃ and VOCs. Conclusion: M2 emitted lower concentration of odorous compounds than M1. Moreover, M2 could maintain the optimum temperature condition for a swine house during the cooler season. The plug-flow ventilation-horizontal biofilter system could be used for pig houses to minimize air pollution produced by swine farming activities and maintain optimum microclimate conditions for pigs.

• Journal of Environmental Health Sciences
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• v.39 no.6
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• pp.541-549
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• 2013

Objectives: We analyzed the characteristics of hazardous air pollutants (HAPs) in road tunnels in Seoul. Methods: Particle matter ($PM_{10}$), elemental carbon (EC), organic carbon (OC), and 16 species of polycyclic aromatic hydrocarbons (PAHs) in two road tunnels (NS tunnel and HJ tunnel) were sampled and analyzed from 2007 to 2011. Results: Levels of $PM_{10}$ and carbon ingredients which were mainly emitted from diesel-fueled vehicles showed a declining tendency in both road tunnels. PAHs levels in HJ were declining slightly while PAHs levels in the NS tunnel fluctuated considerably and showed an increasing tendency. Conclusions: These results suggested that the abatement project of diesel vehicle emissions by the Seoul metropolitan government from 2007 has had an impact on the reduction of DVE into the air, though there exist many things to consider for analyses.

• Journal of Environmental Health Sciences
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• v.43 no.6
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• pp.457-466
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• 2017

Objectives: This study was carried out to investigate the characteristics of volatile organic compounds (VOCs) emitted from sewerage facilities such as a sanitary sewers, outlets, and catch basins. In addition, the dominant malodorous VOCs among the compounds in this study were studied. Methods: Waste gas samples were collected at 27 points in a sanitary sewer in commercial and residental areas. The concentrations of seven volatile organic compounds, including benzene and toluene, in the samples were analyzed by gas chromatograph mass spectrophotometer (GC/MS). Odor concentrations were estimated using the concentration data of the VOCs and each compound's threshold limit value. Results: As a result, it appeared that the average concentration of total observed data for acetaldehyde was 15.98 ppb and benzene 1.87 ppb, toluene 82.31 ppb, ethyl benzene 63.12 ppb, m+p-xylene 15.66 ppb, oxylene 18.73 ppb, and styrene 4.39 ppb. VOC concentrations in the commercial area were higher than those in the residential area. VOC concentrations of waste gas emitted from sewer lines was also higher than those at the outlet and in the catch basins. It was estimated that the main malodorous VOC among the seven VOCs was acetaldehyde. Conclusions: As there is little data on VOC concentrations inside sewer facilities in Korea, these data will be helpful for estimating impact assessment of VOCs and establishing a counter-plan for the abatement of VOCs from sewer facilities in the future.