• Advances in environmental research
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• v.6 no.2
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• pp.83-94
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• 2017

Air quality planning and management requires accurate and consistent records of the air quality parameters. Limited number of monitoring stations and inconsistent measurements of the air quality parameters is a very serious problem in many parts of India. It becomes difficult for the authorities to plan proactive measures with such a limited data. Estimation models can be developed using soft computing techniques considering the physics behind pollution dispersion as they can work very well with limited data. They are more realistic and can present the complete picture about the air quality. In the present case study spatio-temporal models using Linear Genetic Programming (LGP) have been developed for estimation of air quality parameters. The air quality data from four monitoring stations of an Indian city has been used and LGP models have been developed to estimate pollutant concentration of the fifth station. Three types of models are developed. In the first type, models are developed considering only the pollutant concentrations at the neighboring stations without considering the effect of distance between the stations as well the significance of the prevailing wind direction. Second type of models are distance based models based on the hypothesis that there will be atmospheric interactions between the two stations under consideration and the effect increases with decrease in the distance between the two. In third type the effect of the prevailing wind direction is also considered in choosing the input stations in wind and distance based models. Models are evaluated using Band Error and it was observed that majority of the errors are in +/-1 band.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.3
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• pp.1-9
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• 1995

In the B-ISDN using satellite between geo-satellites and earth stations, the laser having high security and broad band width has to be used as a carrier for transmitting massive information of visual, vocal, and high rate data. In this paper, by computer simulation we analyzed the number of optical detector array of optical satellite communication downlink in case of using channel coding and no channel coding for BISDN between geo-satelites and earth stations under clear weather condition. It was supposed that 1 watt semiconductor laser was used and as modulation method, the binary FSK was used. The data rate of 10Gbps was used for B-ISDN. Also, hardly affected by atmospheric absorption 1.55$\mu$m wave-length was used to reduce influence of dispersion and chirp generated at a high speed transmission. We analyzed the received power, SNR and BER. The number of optical detector array was determined to satisfy for the BER less than 10$^{-7}$. Also, we ananlyzed the possibility of reducting the number of optical detector array in case of using channel coding. the number of optical detector array is one in the region where the elevation nangle is between 38$^{\circ}$ and 90$^{\circ}$ and two where the elevation angle is between 33$^{\circ}$ and 37$^{\circ}$ and three where the elevation angle is between 30$^{\circ}$ and 32$^{\circ}$ and increases per one as the elevation angle decreases per 1.deg.. So in the region where the elevation angle is 25$^{\circ}$, the number of optical detector arrays is eight. In case of using channel coding, the number of optical detector arrays decreases to five in the region where the elevation angle is 25$^{\circ}$. Therefore, we remaark the advantage of the channelcoding to decrease the size of received antenna and the number ob optical detector arrays.

• Journal of Radiation Protection and Research
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• v.39 no.4
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• pp.176-181
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• 2014

The object of this paper is to evaluate the fission product inventories and radiological doses in a non-LOCA event, based on the U.S. NRC's regulatory methodologies recommended by the TID-14844 and the RG 1.195. For choosing a non-LOCA event, one fuel assembly was assumed to be melted by a channel blockage accident. The Hanul nuclear power reactor unit 6 and the CE $16{\times}16$ fuel assembly were selected as the computational models. The burnup cross section library for depletion calculations was produced using the TRITON module in the SCALE6.1 computer code system. Based on the recently licensed values for fuel enrichment and burnup, the source term calculation was performed using the ORIGEN-ARP module. The fission product inventories released into the environment were obtained with the assumptions of the TID-14844 and the RG 1.195. With two kinds of source terms, the radiological doses of public in normal environment reflecting realistic circumstances were evaluated by applying the average condition of meteorology, inhalation rate, and shielding factor. The statistical analysis was first carried out using consecutive three year-meteorological data measured at the Hanul site. The annual-averaged atmospheric dispersion factors were evaluated at the shortest representative distance of 1,000 m, where the residents are actually able to live from the reactor core, according to the methodology recommended by the RG 1.111. The Korean characteristic-inhalation rate and shielding factor of a building were considered for a series of dose calculations.

• Environmental Analysis Health and Toxicology
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• v.27
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• pp.8.1-8.10
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• 2012

Objectives: The goal was to model and quantify the atmospheric concentrations of volatile organic compounds (VOCs) as the result of the Hebei Spirit oil spill, and to predict whether the exposure levels were abnormally high or not. Methods: We developed a model for calculating the airborne concentration of VOCs that are produced in an oil spill accident. The model was applied to a practical situation, namely the Hebei Spirit oil spill. The accuracy of the model was verified by comparing the results with previous observation data. The concentrations were compared with the currently used air quality standards. Results: Evaporation was found to be 10- to 1,000-fold higher than the emissions produced from a surrounding industrial complex. The modeled concentrations for benzene failed to meet current labor environmental standards, and the concentration of benzene, toluene, orthometa- para-xylene were higher than the values specified by air quality standards and guideline values on the ocean. The concentrations of total VOCs were much higher than indoor environmental criteria for the entire Taean area for a few days. Conclusions: The extent of airborne exposure was clearly not the same as that for normal conditions.

• Smart Media Journal
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• v.8 no.4
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• pp.38-45
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• 2019

When there is a spray flow such as from a pesticide nozzle, winds affect the droplet flow of a rotary-wing drone accompanied by a strong wake, with a severe oscillation. Especially, during forwarding flights or when winds come from the side, compare to a simple hovering flight as the droplet is in the effect of aerodynamic drag force, the effect of spraying region becomes even larger. For this reason, the spraying of pesticides using drones may cause a greater risk of scattering or a difference in droplet dispersion between locations, resulting in a decrease in efficiency. Therefore, through proper numerical modeling and its applied simulation, an indication tool is required applicable for the various flight and atmospheric conditions. In this research, we completed both experiment and numerical analysis for the strong downwash from the rotor and flight velocity of the drone by comparing the probability density function of droplet distribution to build a spraying system that can improve the efficiency when spraying droplets in the pesticide spray drone.

• Journal of Radiation Protection and Research
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• v.13 no.2
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• pp.41-51
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• 1988

In order to develop a food-chain computer code suitable to the environmental conditions of Korea, the FOOD III code was partially modified. The excution results for Korean male-adult were compared to those from the Canadian version of FOOD III to deduce a more realistic approach in dose assessment. The amounts of Mn-54, Co-58, Co-60, I-131 and I-132 released from Kori unit 1 in1984 were used as the source terms for the sample calculation. The maximum atmospheric dispersion factor(X/Q) value on the site boundary was applied. Through the code modification, organ doses decreased by about $20{\sim}70%$ and the effective committed dose equivalent by about 40% to be $7.935{\times}10^{-6}Sv/y$ which is 0.16% of the ICRP limit, $5{\times}10^{-3}Sv/y$.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.148-148
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• 2018

Land subsidence caused by excessive groundwater pumping is a serious hydro-geological hazard. The spatial variability in land use, unbalanced groundwater extraction and aquifer characteristics are the key factors which make the problem more difficult to monitor using conventional methods. This study uses the European Space Agency (ESA) Sentinel satellites to investigate and monitor land subsidence varying with different land covers and groundwater use in the arid Quetta valley, Pakistan. The Persistent Scattering Differential Interferometry of Synthetic Aperture Radar (PS-DInSAR) method was used to develop 28 subsidence interferograms of the study area for the period between 16 Oct 2014 and 06 Oct 2016 using ESA's Sentinel-1 SAR data. The uncertainty of DInSAR result is first minimized by removing the dynamic effect caused by atmospheric factors and then filtered using the radar Amplitude Dispersion Index (ADI) to select only the stable pixels. Finally the subsidence maps were generated by spatially interpolating the land subsidence at the stable pixels, the comparison of DInSAR subsidence with GPS readings showed an R 2 of 0.94 and mean absolute error of $5.7{\pm}4.1mm$. The subsidence maps were also analysed for the effect of aquifer type and 4 land covers which were derived from Sentienl-2 multispectral images. The analysis show that during the two year period, the study area experienced highly non-linear land subsidence ranging from 10 to 280 mm. The subsidence at different land covers was significantly different from each other except between the urban and barren land. The barren land and seasonally cultivated area show minor to moderate subsidence while the orchard and urban area with high groundwater extraction rate showed excessive amount of land subsidence. Moreover, the land subsidence and groundwater drawdown was found to be linearly proportional to each other.

• Journal of Environmental Impact Assessment
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• v.28 no.4
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• pp.413-426
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• 2019

Many factories indiscriminately located in the vicinity of residential areas need to be adjusted to quasi-industrial parks or new planning management area. In the present work, the changes of atmospheric $SO_2$ concentration according to clustering of individual location factories throughout Gimpo city into a new area were evaluated using a commercial dispersion model, AERMOD. As a result of the evaluation, it was suggested the possibility of improving the pollution through the relocation of individual factories. The combination of relocation and discharge regulation on the stack height may reduce the overall pollution from Gimpo approximately up to 70%, and some areas achieve maximum 87% decrease. However, the area selected as a cluster zone may show a relatively large increase compared to the change in the total pollution level of Gimpo.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.3
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• pp.299-311
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• 2019

Decommissioning is a critical issue in Korea. Although compared with the operation of nuclear power plants the release of radioactive materials during decommissioning is not expected to be significant, residents should always be protected from radiation exposure. To manage this effectively, Annual Release Objectives (ARO) and Annual Release Limits (ARL) were derived from dose standards in the NSSC Notice and dose limit for the public. Based on meteorological data for the three years from 2008 to 2010 in the Shin Kori nuclear power plant site, atmospheric dispersion and ground deposition factors of gaseous effluent were evaluated using the XOQDOQ computer code. The exposure dose was evaluated using the ENDOS-G computer code. Because of differences in radiological sensitivity according to age groups, the results of Annual Release Objectives (ARO) and Annual Release Limits (ARL) showed significant differences depending on the radionuclides. The evaluation methodology of this study will provide meaningful information for radioactive effluent management for decommissioning of nuclear power plants.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.696-706
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• 2023

Consequences of an anticipated Beyond Design Basis Accident (BDBA) Long-Term Station Blackout (LTSBO) event with complete loss of grid power in the VVER-1200 reactor of Rooppur Nuclear Power Plant (NPP) of Unit-1 are assessed using the RASCAL 4.3 code. This study estimated the released radionuclides, received public radiological dose, and ground surface concentration considering 3 accident scenarios of International Nuclear and Radiological Event Scale (INES) level 7 and two meteorological conditions. Atmospheric transport, dispersion, and deposition processes of released radionuclides are simulated using a straight-line trajectory Gaussian plume model for short distances and a Gaussian puff model for long distances. Total Effective Dose Equivalent (TEDE) to the public within 40 km and radionuclides contribution for three-dose pathways of inhalation, cloudshine, and groundshine owing to airborne releases are evaluated considering with and without passive safety Emergency Core Cooling System (ECCS) in dry (winter) and wet (monsoon) seasons. Source term and their release rates are varied with the functional duration of passive safety ECCS. In three accident scenarios, the TEDE of 10 mSv and above are confined to 8 km and 2 km for the wet and dry seasons, respectively in the downwind direction. The groundshine dose is the most dominating in the wet season while the inhalation dose is in the dry season. Total received doses and surface concentration in the wet season near the plant are higher than those in the dry season due to the deposition effect of rain on the radioactive substances.