• International conference on construction engineering and project management
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• 2022.06a
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• pp.1255-1255
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• 2022

Recently, research on digital twins to generate digital information and manage construction in real-time using advanced technology is being conducted actively. However, in the construction industry, it is difficult to optimize and apply digital technology in real-time due to the nature of the construction industry in which information is constantly fluctuating. In addition, inaccurate information on the topography of construction projects is a major challenge for earthmoving processes. In order to ultimately improve the cost-effectiveness of construction projects, both construction quality and productivity should be addressed through efficient construction information management in large-scale earthworks projects. Therefore, in this study, a 3D digital map-based AR site management work support system for higher efficiency and accuracy of site management was proposed by using unmanned aerial vehicles (UAV) in wide earthworks construction sites to generate point cloud data, building a 3D digital map through acquisition and analysis of on-site sensor-based information, and performing the visualization with AR at the site By utilizing the 3D digital map-based AR site management work support system proposed in this study, information is able to be provided quickly to field managers to enable an intuitive understanding of field conditions and immediate work processing, thereby reducing field management sluggishness and limitations of traditional information exchange systems. It is expected to contribute to the improvement of productivity by overcoming factors that decrease productivity in the construction industry and the improvement of work efficiency at construction sites.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.1085-1092
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• 2022

Travel distance is a parameter mainly used in the objective function of Construction Site Layout Planning (CSLP) automation models. To obtain travel distance, common approaches, such as linear distance, shortest-distance algorithm, visibility graph, and access road path, concentrate only on identifying the shortest path. However, humans do not necessarily follow one shortest path but can choose a safer and more comfortable path according to their situation within a reasonable range. Thus, paths generated by these approaches may be different from the actual paths of the workers, which may cause a decrease in the reliability of the optimized construction site layout. To solve this problem, this paper adopts reinforcement learning (RL) inspired by various concepts of cognitive science and behavioral psychology to generate a realistic path that mimics the decision-making and behavioral processes of wayfinding of workers on the construction site. To do so, in this paper, the collection of human wayfinding tendencies and the characteristics of the walking environment of construction sites are investigated and the importance of taking these into account in simulating the actual path of workers is emphasized. Furthermore, a simulation developed by mapping the identified tendencies to the reward design shows that the RL agent behaves like a real construction worker. Based on the research findings, some opportunities and challenges were proposed. This study contributes to simulating the potential path of workers based on deep RL, which can be utilized to calculate the travel distance of CSLP automation models, contributing to providing more reliable solutions.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.1209-1216
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• 2022

The majority of construction site incidents occur due to a lack of hazard awareness among workers on job sites. This lack of awareness is despite mandatory construction safety training, typically in the form of written content (safety manuals) or of images depicting hazards. To reduce job-site injuries and fatalities, general contractors have started adopting Virtual Reality (VR) to impart safety training to job site personnel. VR safety training can take the form of an immersive simulation comprising potential safety hazards intentionally embedded into a virtual job site; users are required to identify these hazards within a specified time frame with the expectation that they will be more adept at recognizing hazards on an actual job-site, resulting in fewer accidents. This research study seeks to identify the actual impacts of VR on construction safety awareness among participants. The research addresses the following question: Does VR improve hazard recognition awareness? The primary objective is to evaluate participants' performance of past construction safety awareness against present construction safety awareness after receiving VR training. Participants were asked to complete a multiple-choice Qualtrics™ questionnaire. The results of the study showed a statistically significant knowledge gain advantage with respect to hazard recognition and construction safety awareness with the use of interactive, immersive VR over a more conventional and passive safety training method.

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2452-2457
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• 2024

To obtain site-specific values of the Derived Concentration Guideline Levels (DCGLs) for decommissioning of KRR-1&2, the soil density and distribution coefficient values for Cs-137, a major contaminant radionuclide, were determined. The soil density was evaluated according to the test method established by the Korean Agency for Technology and Standards of the Ministry of Trade, Industry, and Energy (KATS). The distribution coefficient was evaluated using a batch test. The validity of using the evaluated soil density and distribution coefficient as site-specific values was assessed through radiation dose assessment reflecting these values. Average soil density value obtained was 1.738 g/cm³, which was within the typical range of normal soil density, 1.0-1.8 g/cm³. The average distribution coefficient value was 7,754 mL/g. Applying the maximum, average, and minimum values of the evaluated soil density and distribution coefficient showed similar radiation dose results, thus suggesting that it is reasonable to use the average values of each parameter as site-specific values. Findings of this study can help determine DCGLs that reflect the characteristics of the research reactor site.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.3
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• pp.205-215
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• 2008

SITES(Site Information and Total Environmental Data Management System) has been developed for the purpose of systematically managing site characteristics and environmental data produced during the pre-operational, operational, and post-closure phases of a radioactive waste disposal facility. SITES is an integration system, which consists of 4 modules, to be available for maintenance of site characteristics data, for safety assessment, and for site/environment monitoring; site environmental data management module(SECURE), integrated safety assessment module(SAINT), site/environment monitoring module(SUDAL) and geological information module for geological data management(SITES-GIS). Each module has its database with the functions of browsing, storing, and reporting data and information. Data from SECURE and SUDAL are interconnected to be utilized as inputs to SAINT. SAINT has the functions that multi-user can access simultaneously via client-server system, and the safety assessment results can be managed with its embedded Quality Assurance feature. Comparison between assessment results and environmental monitoring data can be made and visualized in SUDAL and SITES-GIS. Also, SUDAL is designed that the periodic monitoring data and information could be opened to the public via internet homepage. SITES has applied to the Wolsong low- and intermediate-level radioactive waste disposal center in Korea, and is expected to enhance the function of site/environment monitoring in other nuclear-related facilities and also in industrial facilities handling hazardous materials.

• Journal of the Korean Applied Science and Technology
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• v.32 no.4
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• pp.649-660
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• 2015

Data obtained from the Calpuff inverse modeling estimate the emission amount of pollutants, and enable to establish the aim for reduction through the comparison of various cases. This study pursued to accumulate the fundamental data by the Calpuff inverse modeling for five areas in the vicinity of Donghae harbor, which focused on reduction of atmospheric fine dust. As a result of evaluation of the allowed emission amount for local sites, site-D required the most reduction, $4.95{\mu}g/m^2{\cdot}S$, based on the atmospheric guideline, $50{\mu}g/m^3$. The theoretical mitigation could decrease the average concentration of PM10 to $42.6{\mu}g/m^3$ for the study field (Donghae waste water treatment plant). Modeling only for site-A emission showed the potential concentration around the residential area of Donghae harbor, $40{\sim}50{\mu}g/m^3$. However, it will rise over $50{\mu}g/m^3$ with the addition of background level. Therefore no more emission would be allowed. Site-B including commercial area and unpaved field required the reduction of $0.11{\mu}g/m^2{\cdot}S$ due to vehicles and fugitive dust. Site-C and E did not emit additional pollutants.

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.119-125
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• 2014

This study evaluated the environmental impacts of a soil washing (SW) process, especially, we compared the on-site and off-site remediation of TPH-contaminated soil using green and sustainable remediation (GSR) tool. To assess relative contribution of each stage on environmental footprints in the entire soil washing process, we classified the process into four major stages: site foundation (stage I), excavation (stage II), separation & washing (stage III), and wastewater treatment (stage IV). In on-site SW process, the relative contribution of $CO_2$ emissions and energy consumption were 87.1% and 80.4%, respectively in stage I, and in off-site SW process, the relative contribution of $CO_2$ emissions and energy consumption were 82.7% and 80.5%, respectively in stage II. In conclusion, the major factor contributing environmental impact in the SW process were consumable materials including steel and stainless steel for washing equipment in on-site treatment and fuel consumption for transportation of soil in off-site treatment.

• Journal of the Korean Professional Engineers Association
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• v.34 no.4
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• pp.17-29
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• 2001

After participating in the 2nd, Asian Civil Engineering Conference which is subjected by Japan, a trip of site during construction recent was done. The country Is being developed to use effectvely by the methods of aqua-line, truss suspersion bridge. double deck bridge, etc. The Japanese engineers have a pride to do their best for the construction In the given environment. 1 want to notify that our civil engineers must have the responsibility to develop the technical engineering, to make the useful country and to resolve the environmental problem via the oversea experience like as.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.04a
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• pp.257-264
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• 1997

Seismic responses of the Hualien large scale seismic test model on a layered soil site are estimated for two recorded earthquakes and the analysis results are then compared and evaluated with the recorded responses. The method adopted for the analysis is based on substructuring method using a lumped parameter model in both the frequency and time domain. the study results indicate that the proposed method can reasonably estimate the earthquake responses of a soil-structure interaction system for engineering purposes.

• Journal of the Earthquake Engineering Society of Korea
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• v.21 no.2
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• pp.95-103
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• 2017

In order to modeling seismic isolation system such as lead-rubber bearing (LRB), bilinear model is widely used by many researchers. In general, an actual force-displacement relationship for LRB has a smooth hysteretic shape. So, Bouc-Wen model with smooth hysteretic shape represents more accurately actual hysteretic shape than bilinear model. In this study, seismic responses for seismically isolated nuclear power plant (NPP) with LRB modelled by Bouc-Wen and bilinear models are compared with those of NPP without seismic isolation system. To evaluate effect of earthquake characteristics for seismic responses of NPP isolated by LRB, 5 different site class earthquakes distinguished by Geomatrix 3rd Letter Site Classification and artificially generated earthquakes corresponding to standard design spectrum by Reg. Guide 1.60 are used as input earthquakes. From the seismic response results of seismically isolated NPP, it can be observed that maximum displacements of seismic isolation modelled by Bouc-Wen model are larger than those by bilinear model. Seismic responses of NPP with LRB is significantly reduced than those without LRB. This reduction effect for seismic responses of NPP subjected to Site A (rock) earthquakes is larger than that to Site E (soft soil) earthquakes.