• KIEAE Journal
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• v.13 no.4
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• pp.33-41
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• 2013

The impervious area on the surface of urban area has been increased as buildings and artificial land cover have continually been increased. Urban development has gradually decreased the green zone in downtown and alienated the city from the natural environment on outskirt area devastating the natural ecosystem. There arise the environmental problems to urban area including urban heat island phenomenon, urban flood, air pollution and urban desertification. As one of urban plans to solve such problems, green roof system is attracting attentions. The purpose of this study was to investigate flood discharge and heat reduction effect according to the green roof system and to quantify effect by analyzing through simulation water and heat cycle before and after green roof system. For the analysis, Distributed hydrologic model, WEP (Water and Energy transfer Processes) and WEP+ model were used. WEP was developed by Dr. Jia, the Public Works Research Institute in Japan (Jia et al., 2005), which can simulate water and heat cycle of an urban area with complex land uses including calculation of spatial and temporal distributions of water and heat cycle components. The WEP+ is a visualization and analysis system for the WEP model developed by Korea Institute of Construction Technology (KICT).

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1248-1253
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• 2009

Although there have been many efforts to reduce accidents on construction sites, such accidents continue to occur. New technologies have recently been developed to improve safety and their performance needs to be evaluated to determine their suitability prior to the application. The assessment for safety performance mainly is conducted depending on qualitative and subjective judgment of supervisors. However, there are rarely proper approaches to assess such qualitative measures. Therefore, we propose a fuzzy-based approach to assessing the performance of a new technology. The assessment of a new technology, called a mobile detector (MD), was carried out as a case study. The output is compared with those by a numerical simulation. As a result, the fuzzy-based performance assessment is shown to be appropriate for this evaluation.

• Journal of the Korea Safety Management & Science
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• v.11 no.2
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• pp.111-115
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• 2009

As shown in the accident analysis from 2007, it has been found that causes of accidents on large-scale projects are different from those found in general construction projects. A 300-question survey regarding systematic and practical aspects of safety problems at construction sites was distributed to ten (10) different companies. Participants were to respond subjectively, so that the results could be used to assemble the first formal questionnaire survey. They were collected and compiled by an advisory committee for this study. The resulting surveys were then sent to the division chiefs of the top 100 construction companies in Korea, in order to improve the response rate. The Department of Safety & Health Direction, and the :Ministry of Labor, ROK sent the same sheets to medium and small construction companies that placed within 101-200th of all Korea construction companies. The above safety engineers were classified into four (4) levels, from 1st to 4th, followed by the project dollar amount and risk level. Formulae were developed to assign safety engineers to construction sites by engineer level, the project dollar amount, and the project risk level. Conclusions are summarized as follows: 1) Reviewing the assignment system of experienced safety engineers to large scaled projects - The more experienced the engineers assigned to a project, the higher the level of accident prevention. 2) Enforcing the assignment of advanced level safety engineers to large-scaled sites - At least one advanced-level safety engineer should be assigned to construction sites with projects valued at $15million USD (15,000,000,000). 3) For assigning safety engineers by risk level - Twenty models have been developed to calculate the number of safety engineers to be assigned by risk level. In the future, risk level for each job should be established by the government (as is now the practice in Germany).

• Nuclear Engineering and Technology
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• v.50 no.5
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• pp.751-757
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• 2018

In this article, a UV sensor that is an appropriate tool for fire detection has been designed and constructed. The structure of this UV sensor is an air-filled single-wire detector that is able to operate under normal air condition. A reflective CsI photocathode is installed at the end of the sensor chamber to generate photoelectrons in the ion chamber. An electric current is produced by accelerating photoelectrons to the anode in the electric field. The detector is able to measure the intensity of the incident UV rays whenever the current is sufficiently high. Therefore, the sensitivity coefficient of this sensor is found to be $7.67{\times}10^{-6}V/photons/sec$.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.70-71
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• 2015

Construction period is longer than the non-disclosure in civil construction of apartment house. And this process is intensive at the beginning and end of construction. Because this project management expertise is required. Nevertheless, subsidiary work(Working avoid a tendency of advanced technician, Frequent turnover and employment contracts, etc.) management attention of construction is at a lower level. Because of, there are the bad factors(trial and error, finish degradation, etc.). Therefore, this study analyzed Hindrance Factor of quality control on apartment complex construction work and presented importance of civil construction engineer's role. Also, forms of civil construction engineer, Performance experience and technical Strength of apartment complex construction was investigated for the construction. To this end, It analyzes the relationship between forms of civil construction engineer, Performance experience and technical Strength of apartment complex construction and Construction of evaluation as required by Construction Technology Management Act.

• Geomechanics and Engineering
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• v.21 no.2
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• pp.207-213
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• 2020

Umbrella Arch Method (UAM) often employed in the tunnel construction under poor rock mass conditions in Korea. Insertion of steel pipes at the periphery of the tunnel and infiltration of grouts along the pipes into the rock masses increases tunnel stability. There are two major effects of grouts expected at the tunnel face: 1) increase of face stability by enhancing the frictional resistance of discontinuities and 2) decrease of permeability along the rock masses. Increase of resistance and decrease of permeability requires a certain curing time for the grout. In Korea, we require 24 hours for curing of grout, which means no progress of excavation for 24 hours after infiltration of grouts. This step delays the tunnel construction sequences. To eliminate such inefficiency, we propose MTG (Method for Tunnel construction using Grouting technology), which uses extended length of steel pipes (14 m) compared to conventional pipe roof method (12 m). The merit of MTG is the reduction of curing time. Because of the approximately 2 m extension of the length of steel pipe, blasting can be done after infiltration of grouting. For this paper, we conducted experiments on the shear strength behaviors of grout infilled rock joint with elapsing of curing time and blasting induced vibration. The results show that blasting induced vibration under MTG does not influence the mechanical features of grout material, which indicates no influence on the mechanical behaviors of grout, contributing to the stability of tunnels during excavation. This result indicates that MTG is a cost effective and fast construction method for tunneling in Korea.

• Advances in environmental research
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• v.1 no.2
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• pp.125-142
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• 2012

Clean development mechanism (CDM) validity study was conducted to suggest better and more adaptable CDM scenario on water treatment plant (WTP). Potential four scenarios for CDM project; improvement of intake pumping efficiency, hydro power plant construction, solar panel construction and system optimization of mechanical mixing process were evaluated on S-WTP in Korea. Net present value (NPV) of each scenario was estimated based on sensitivity analysis with the variable factors to investigate the CDM validity percentile. Hydro power plant construction was the best option for CDM business with 97.76% validity and $1,127,069 mean profit by 9,813 $tonsCO_2e$/yr reduction. CDM validity on improvement of intake pumping efficiency was 90.2% with $124,305 mean profit by huge amount of $CO_2$ mitigation (10,347 $tonsCO_2e$/yr). System optimization of mechanical mixing process reduced 15% of energy consumption (3,184 $tonsCO_2e$/yr) and its CDM validity and mean profit was 77.25% and $23,942, respectively. Solar panel construction could make the effect of 14,094 $tonsCO_2$ mitigation annually and its CDM validity and mean profit was 64.68% and $228,487, respectively.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.120-121
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• 2019

The construction industry is known to be one of the representative industries that generate fine dust. Therefore, reducing the amount of fine dust generated in construction sites is very important for the overall fine dust management. Based on this, this study proposed the concept of fine dust measurement and removal technology combined with advanced technologies such as drones and IoT. The qualitative, quantitative and risk elimination effects that can be expected when applying the proposed technique are analyzed. We will verify the effectiveness of the proposed concept through system development and field application, and evaluate specific economic feasibility through cost analysis. The proposed concept will be validated through system development and field application and evaluated specific economics through cost analysis.

• Advances in environmental research
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• v.3 no.4
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• pp.367-377
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• 2014

In this study, we investigated a life cycle assessment (LCA) of six roof-waterproofing systems [asphalt (C1), synthetic polymer-based sheet (C2), improved asphalt (C3), liquid applied membrane (C4), Metal sheet with asphalt sheet (N1), and liquid applied membrane with asphalt sheet (N2)]for reinforced concrete building using an architectural model. To acquire accurate and realistic LCA results, minimum units of material compositions for life cycle inventory and real data for compositions of waterproofing materials were used. Considering only materials and energy demands for waterproofing systems per square meter, higher greenhouse gas (GHG) emissions could be generated in the order of C1 > N2 > C4 > N1 > C2 > C3 during construction phase. However, the order was changed to C1 > C4 > C3 > N2 > N1 > C2, when the actual architecture model was applied to the roof based on each specifications. When an entire life cycle including construction, maintenance, and deconstruction were considered, the amount of GHG emission was in the order of C4 > C1 > C3 > N2 > C2 > N1. Consequently, N1 was the most environmental-friendly waterproofing system producing the lowest GHG emission. GHG emissions from maintenance phase accounted for 71.4%~78.3% among whole life cycle.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.68-73
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• 2007

Civil engineering construction work has always been accompanied by a high proportion of tasks that are either dangerous or unpleasant or both. Enhancing the general working environment and boosting safety levels are critical issues for the industry. In addition to that, the industry has been slow to utilize automation & robot technology, and there is substantial scope for the use of technology th boost efficiency, cut costs and improve quality levels in construction. In a bid to address this issue, Ministry of Construction & Transportation launched a five-year project in 2003 entitled Development of Intelligent Excavating System. The aim of the project is to use telecommunications and robotics technology to minimize inefficiencies and eliminate the dangerous and unpleasant aspects of tile construction process through the development of specific applications such as IT-equipped construction machinery and advanced construction management systems. In this paper, the project introduces on the research and development content related to multi-disciplinary, a intuitive operator control unit(Robot Technology) included.