• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.464-469
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• 1998

A coincidence gamma-ray spectroscopy method was applied to reduce the background radioactivity for measuring the activity of radioisotopes in a sample in the presence of environmental natural radioactivity. A HPGe detector was used for the coincident spectrum as a main detector and a NaI(Tl) scintillation detector for gating purposes as an associated detector. For coincidence spectroscopy the whole energy spectrum of associated detector was used instead of gate signals. The coincident events obtained from the gating spectrum was evaluated by a coincidence computer program in this study instead of timing circuit. In this work, the background of detection environment was reduced to factor 100 and peaks to be determined was reduced to factor 30 using the coincidence gamma-ray spectroscopy.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.322-326
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• 2010

This study shows that atmospheric TPM concentrations and THg concentrations in precipitation measured in China were higher that those measured in Korea. TPM concentrations and THg concentrations in precipitation during the cold periods were generally higher than those during the warm periods in both China and korea. In China, variations of THg concentration in precipitation during the cold and warm periods were influenced by scavenging of both TPM and RGM. Different from China, in Korea, variations of THg concentration in precipitation during the cold period were also influenced by scavenging of both TPM and RGM; however, those during the warm periods were dominantly governed by scavenging of RGM.

• Korean Journal of Computational Design and Engineering
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• v.9 no.4
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• pp.406-415
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• 2004

The industrial environment for shipbuilding in 21st century requires increase in few type of ships and marine structures, international cooperation and globalization, while virtual enterprise environment is rapidly establishing. On the other hand, more and more efforts will be spent on internet based distributed and collaborative environment rather than being spent on unit level automations such as CAD, CAM and CAE, and the link between them. Recent internet technology and information technology in heterogeneous environment are being applied in shipbuilding industry as well as in other industries. While these technology are rapidly adopted in major shipyards, many small and medium-sized shipyards does not have enough resources to introduce system designed for large enterprise. In this paper, a prototype of Internet technology based basic planning system is implemented for the small and medium sized shipyards based on the internet technology and concurrent engineering concept. First, the system is designed from the user requirements. Then standardized development environment and tools are selected. These tools are used for defining and evaluating core application technologies for the system development. This can guarantee the survival of small and medium-sized shipyards in 21st century industrial environment.

• Advances in environmental research
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• v.6 no.2
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• pp.139-146
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• 2017

The purpose of this study was to determine the present air pollutant concentrations and predicted levels for next 30 years in urban environment of Karachi city. For that, a total of fifty measurements were made for each twenty selected locations of the city. The locations were selected on the basis of land use pattern such as residential, commercial, industrial settlements, open areas, congested traffic and low traffic areas for investigation of air pollutants variability and intensity. The measurements were taken continuously for six months period using PM Meter, Model AEROCET 531 and Ambient Air Quality Meter, Model AAQ 7545. The concentration of air pollutants were found higher at Al Asif Square and Maripur Road due to higher intensity of traffic and at Korangi Crossing because of industrial areas. The level of pollutants was lower at Sea View owing to lower traffic congestion and transportation of pollutants by sea breezes.

• Nuclear Engineering and Technology
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• v.52 no.5
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• pp.956-963
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• 2020

Dose optimization for Radioactive Occupational Personal (ROP) is an important subject in nuclear and radiation safety field. The geometric environment of a nuclear facility is complex and the work area is radioactive, so traditional navigation model and radioactive data field cannot form an effective environment model for dose assessment and dose optimization. The environment model directly affects dose assessment and indirectly affects dose optimization, this is an urgent problem needed to be solved. Therefore, this paper focuses on an environment model used for Dose Assessment and Dose Optimization (DA&DO). We designed a multi-layer radiation field coupling modeling method, and then explored the influence of the environment model to DA&DO by virtual simulation. Then, a simulation test is done, the multi-layer radiation field coupling model for nuclear facilities is demonstrated to be effective for dose assessment and dose optimization through the experiments and analysis.

• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.654-663
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• 2010

Attention has increasingly focused on the pollutant load discharged from rural area since the enforcement of total maximum daily loads (TMDLs) in korea. As one of the methods to control the inflow of pollutant load during wet weather events, local governments are attempting to apply non-point source control facility. To design those facilities appropriately, it is essential to understand the runoff characteristics of pollutants such as TSS, $BOD_5$, $COD_{Cr}$, TP and TN. In the paper, the quantitative analyses for pollutant runoff characteristics were examined in a small rural watershed with the area of about 53 hectares. For a dry weather day and wet weather events, variation patterns of dry weather flow and runoff characteristics of wet weather flows were monitored and investigated. The runoff model using XP-SWMM reflecting the landuse types of the watershed in detail was simulated to perform the sensitivity analyses for several factors influencing on their hydrograph and pollutographs. As a result, for the case of medium and small rainfall events (i. e. total rainfall of 35.8 and 17.5 mm), the impervious area including green house, roof and road which covers relatively low portion of total area (i. e. 16%) caused substantial first flush and the majority of total runoff load. Therefore, it has been concluded that the runoff characteristics of each pollutant and distribution of impervious area should be considered for the establishment of the control strategy of non-point pollutant runoff at a rural area.

• Journal of Korean Society on Water Environment
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• v.29 no.4
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• pp.551-558
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• 2013

The feasibility of water supply as in-stream flow for Mangwall stream was analyzed in terms of water quality and cultivation periphyton using two different types of water resources (e.g., surface water and bank filtration from Han River basin) and three different types of media (e.g., tile, concrete and pebble). The concentrations of organic and inorganic contaminants from the bank filtration were lower than those from surface water by 17.5 - 55.0%. Using water samples collected from Mangwall stream, surface water, and bank filtration, chlorophyll-a, phaeopigment, and growth rate of periphyton were investigated. During 30 day incubation for each water sample, it was observed that filamentous cyanobacteria, Oscillatoriaceae, accounted for 98%, and water velocity of 5 cm/s was optimum for the in situ filamentous cyanobacteria growth. Also, it was deducted for water velocity and chl-a to have an inverse correlation. Meanwhile, the greater the specific surface area of media, the higher the concentration of chl-a. From these results, both water velocity and specific surface area of media should be considered as an combined parameter to deter the growth of filamentous cyanobacteria.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.766-775
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• 2007

The use of toxic chemicals was extended as the industry in Korea has grown dramatically during the last three decades. However, list of toxic substances and limit concentrations in the water environment are not consistent within management of ambient water, drinking water and industrial effluent. This article suggests the systematic framework to classify toxic substances in the water environment and deriving their effluent limits. The most important factor for decision-making to classify toxic substances is whether their concentrations in the water environment are higher than the reference concentrations, estimated by considering human health risk and ecological risk. Using a risk-based reference concentration, the ambient water quality criterion, it is possible to derive the regulatory limit concentrations of toxic substances in drinking water and in industrial effluent. The goal concentrations in the effluent, which guarantee the human and ecological safety, should be determined with scientific investigation, balancing environmental benefit and economical effect, considering availability of treatment technology and identifying characteristics of wastewater from different industries.

• Journal of The Korean Association For Science Education
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• v.17 no.4
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• pp.395-403
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• 1997

In order to study the effect of the 'General Science' course implemented under the 6th science curriculum, high school students' views about the relationship between science/technology and society and their perceptions of science classroom environment were investigated. Four classes (n = 211) were selected from those completed the 'Science I' course under the 5th science curriculum, and 4 another classes (n = 216) which took the 'General Science' course under the 6th science curriculum were selected. In order to compare students' views about the relationship between science /technology and society. 10 items were selected from the VOSTS (Views On Science-Technology-Society) while considering the 6th science curriculum and the 'General Science' textbooks, and administered at the end of the 'Science I' course and at the beginning and end of the 'General Science' course. In order to compare the perceptions of science classroom environment, the Perceptions of Science Classroom Environment Questionnaire, which was prepared from the Individualized Classroom Environment Questionnaire. the Science Laboratory Environment Inventory, and the Classroom Environment Scale. was also administered at the end of the 'Science I' course and the 'General Science' course. The results indicated that the mean VOSTS score of the 6th-curriculum group was lower than that of the 5th-curriculum group, although the difference was not statistically significant. The decrease in the VOSTS score of the 6th-curriculum group during the 'General Science' course was statistically significant. It was also found that unrealistic views such as 'technology is the application of science', and 'corporations should control science/technology' had been formed during the course. However, the 6th-curriculum group had more positive perceptions of science classroom environment. Educational implications are discussed.

• Journal of Information Processing Systems
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• v.14 no.6
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• pp.1445-1456
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• 2018

Environment perception and three-dimensional (3D) reconstruction tasks are used to provide unmanned ground vehicle (UGV) with driving awareness interfaces. The speed of obstacle segmentation and surrounding terrain reconstruction crucially influences decision making in UGVs. To increase the processing speed of environment information analysis, we develop a CPU-GPU hybrid system of automatic environment perception and 3D terrain reconstruction based on the integration of multiple sensors. The system consists of three functional modules, namely, multi-sensor data collection and pre-processing, environment perception, and 3D reconstruction. To integrate individual datasets collected from different sensors, the pre-processing function registers the sensed LiDAR (light detection and ranging) point clouds, video sequences, and motion information into a global terrain model after filtering redundant and noise data according to the redundancy removal principle. In the environment perception module, the registered discrete points are clustered into ground surface and individual objects by using a ground segmentation method and a connected component labeling algorithm. The estimated ground surface and non-ground objects indicate the terrain to be traversed and obstacles in the environment, thus creating driving awareness. The 3D reconstruction module calibrates the projection matrix between the mounted LiDAR and cameras to map the local point clouds onto the captured video images. Texture meshes and color particle models are used to reconstruct the ground surface and objects of the 3D terrain model, respectively. To accelerate the proposed system, we apply the GPU parallel computation method to implement the applied computer graphics and image processing algorithms in parallel.