• Journal of the Korea Institute of Building Construction
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• v.23 no.2
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• pp.175-185
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• 2023

Upon analyzing labor productivity in the construction industry across OECD countries, it was found that in 2019, labor productivity per employee in the South Korean construction industry was lower than that of major developed countries when adjusted for purchasing power parity(PPP). Specifically, when benchmarked against other countries at a base of 100, South Korea scored 76.9 in the United States, 88.4 in Japan, and 85.1 in the OECD average. Notably, South Korea ranked 25th in labor productivity per employee in the construction industry among 35 OECD countries in 2019, indicating a low standing. A comparative analysis of the construction market size and labor productivity in the construction industry across OECD countries revealed that larger construction markets did not necessarily correlate with higher labor productivity. To enhance labor productivity in the construction industry, this study proposed the active implementation of smart construction technology at construction sites and the promotion of on-site assembly work using off-site construction(OSC) technology, rather than traditional on-site labor. Moreover, it was recommended that the development of modular construction methods and technologies be expanded. In the future, if off-site production methods and modules are further developed through advanced robotics and factory automation, labor productivity is anticipated to increase due to the restructuring of production methods, such as manufacturing.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.965-975
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• 2014

Pretension PSC (Prestressed Concrete) members are subjected to a certain limit of size as they are generally produced in the off-site plant and transferred to the site due to the large scale of the product on system. In this study, a portable pretensioning production system has been developed, which allow us to apply the pretension method on site. Considering that a 50m span PSC girder using the pretension method requires a pressing device to endure a large jacking force, the portable pretension production system has to ensure safety against such a large pretension jacking force. In this study, the portable pretensioning system to produce a 50m span pretension girder was manufactured by using CFT (Concrete Filled steel Tube) members. In order to understand the stability of the system and the behavior of the elements, a static loading test was conducted and the stability of the proposed portable pretensioning production system was confirmed. The developed portable pretension system was applied to several construction sites and was investigated the problems on site. During the pretension girder and slab members that was producted by this pretension system in construction site, it has be found the several advantages such as simple fabrication processes, reduction of prestress-loss, and a decrease of 15% compared with the fabrcation cost of post-tension girder. After due consideration of the problems, this portable pretension system will be improved.

• Journal of the Korean Institute of Gas
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• v.22 no.5
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• pp.31-37
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• 2018

The distrust about chemical plant safety have been increased by occurring the major industrial accidents. Chemical plants have become more and more enlarged and sophisticated to increase production amount and decrease cost. So hazard of industrial accidents also have been increased. In this situation, quantitative risk assessment is activated by introducing OCA(Off-site Consequence Analysis). So it is possible to analyze the objective hazard of chemical plant. Currently OCA focus on the end point of hazardous area by fire/explosion/dispersion. But in this case, it is possible to analyze the industrial accident effect to near the chemical plant but hard to consider the actual hazard by frequency and population density. This study analyzes the validity about application of F-N curve to OCA by compare end point with F-N curve about accident.

• Korean Journal of Construction Engineering and Management
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• v.22 no.1
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• pp.98-105
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• 2021

Recently, there have been many changes in the domestic construction industry. OSC (Off-Site Construction) is expected to solve these problems, and it is emerging as a way to inspire innovation in the domestic construction production system. OSC, which has only recently attracted attention again after previous studies have failed, is lacking in research on preception surveys and customized performance measurements compared to overseas. This study investigated the perceptions of construction industry workers on OSC through a survey, and examined differences in perceptions of each subject and the relative importance of performance indicators. In general, the need for introduction and development of OSC was recognized. Also, drivers and obstacles inhibiting more use of OSC were analyzed. The relative importance for performance indicators and differences in perceptions of each subject were identified. Then, this study suggests plans for diffusion and revitalization of OSC, and key performance indicator for OSC based PC structure apartment housing.

• Korean Journal of Construction Engineering and Management
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• v.24 no.2
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• pp.24-36
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• 2023

OSC is drawing attention to supplement limitations such as productivity problems and on-site safety and quality problems of existing on-site labor-oriented construction production methods. In order to activate the introduction and use of OSC in the domestic construction market, it is important to innovate the technology applied to each stage of OSC process (design and engineering, factory manufacturing, site assembly, and maintenance), but it is also necessary to develop a project management method suitable for OSC method. However, research related to OSC currently being conducted in Korea is mainly in terms of related technology development, and research on deriving project management measures for the success of OSC projects is insufficient. Therefore, it is time for research on deriving a project management plan based on the core success factors of the OSC project. Therefore, by conducting importance-performance analysis on 69 OSC critical success factors derived from the previous study, the study was conducted to derive key improvement factors for OSC introduction and utilization improvement and to provide implications for this. The results of this study are expected to have useful implications for the R&D planning and policy-making process for OSC activation in the future.

• Korean Journal of Construction Engineering and Management
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• v.25 no.4
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• pp.3-14
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• 2024

Unlike conventional construction production methods, OSC (Off-Site Construction) have many restrictions depending on the production environment and technology, so it is important to develop a design plan considering these restrictions and select the optimal design alternative considering the overall efficiency of the building production process. Accordingly, the construction industry is paying attention to DfMA (Design for Manufacturing & Assembly) to derive the optimal design plan for the OSC project. Leading OSC countries such as Singapore and the United Kingdom have recognized the need to apply DfMA and presented DfMA guidelines and application strategies suitable for the characteristics of the OSC industry, and several researchers are conducting research to integrate DfMA into the construction industry. However, in the case of Korea, the need for industrial application and industrial application of DfMA is recognized, but there are no methods and tools necessary to implement the concept of DfMA in the design of actual construction projects. Therefore, this study aims to present the basic direction of strategy for applying DfMA and developing tools for the development of the domestic OSC industry by analyzing the development and application of DfMA in overseas construction. The results of this study can be used as basic data for the development of DfMA tools suitable for the domestic OSC industry and the establishment of policies related to DfMA in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.888-895
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• 2020

In the construction industry, off-site construction (OSC) is drawing attention as a production method due to changes in working hours and the supply and demand of manpower. In 1991, there was a policy of spreading and expanding the use of precast concrete (PC) apartment homes, but they have not been actively used so far since they were discontinued due to quality problems. In this study, policy tasks were analyzed to motivate the application of OSC-based PCs in the apartment housing sector, and policy directions were derived by conducting focus group interviews (FGI). Nine policies are suggested regarding the following topics: PC apartment supply quantity provision, priority application of public housing, priority supply of public housing, preferential floor area ratio, funding, tax support, improvement of business area structure, improvement of delivery method, factory certification system, and training of experts. The results of the FGIs are as follows. First, in order to revitalize PC apartment homes, leading efforts from the public sector are required. Second, rather than reorganizing the business sector or introducing a new delivery method, a policy direction that induces the strengthening of cooperation is desirable. Third, PC activation should be promoted on an institutional basis for securing appropriate construction costs and quality.

• 한국연소학회:학술대회논문집
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• 2000.05a
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• pp.152-161
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• 2000

The catalytically stabilized combustion of $CH_4$-air mixture on platinum catalyst was investigated numerically using a 2-D boundary layer model with detailed heterogeneous and homogeneous chemistries. The actual surface site density of monolith coated with platinum was decided by the comparison with experimental data. The comparisons were made between results for cases where only heterogeneous chemistry was allowed and both heterogeneous and homogeneous chemistries were allowed. It was found that the homogeneous reaction in the monolith had little effect on the change of temperature profile, methane conversion rate and light off location. The contributions of each reactions related with CO formation were discussed on the surface. The effects of operation conditions such as equivalence ratio, temperature, velocity and pressure at the entrance were studied. In thermal combustor, CO and NOx was produced less than 1 ppm at the exit and the production of $N_{2}O$ was more dominant than that of NO.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.5
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• pp.743-748
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• 2017

Objective: Based on rapid advancement of genetic modification techniques, genomic editing is expected to become the most efficient tool for improvement of economic traits in livestock as well as poultry. In this study, we examined and verified the nickase of mutated CRISPR-associated protein 9 (Cas9) to modulate the specific target gene in chicken DF1 cells. Methods: Chicken myostatin which inhibits muscle cell growth and differentiation during myogenesis was targeted to be deleted and mutated by the Cas9-D10A nickase. After co-transfection of the nickase expression vector with green fluorescent gene (GFP) gene and targeted multiplex guide RNAs (gRNAs), the GFP-positive cells were sorted out by fluorescence-activated cell sorting procedure. Results: Through the genotyping analysis of the knockout cells, the mutant induction efficiency was 100% in the targeted site. Number of the deleted nucleotides ranged from 2 to 39 nucleotide deletion. There was no phenotypic difference between regular cells and knockout cells. However, myostatin protein was not apparently detected in the knockout cells by Western blotting. Additionally, six off-target sites were predicted and analyzed but any non-specific mutation in the off-target sites was not observed. Conclusion: The knockout technical platform with the nickase and multiplex gRNAs can be efficiently and stablely applied to functional genomics study in poultry and finally adapted to generate the knockout poultry for agribio industry.

• Journal of the Korean Geographical Society
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• v.46 no.1
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• pp.50-66
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• 2011

Biofuel crops and their economical benefits have been recently researched as one of the alternative energy sources. Very few studies, however, have brought an issue about the impacts of the new cropping on environment, especially water quality. Because biofuel cropping requires more crop production with more fertilizers for cost-effectiveness, water quality near the new crops as well as downstream is expected to be degraded. In this study, the impacts of biofuel crop production on water quality was estimated by scenarios between pre-biofuel cropping and post-biofuel cropping using the previously calibrated SWAT (Soil and Water Assessment Tool) model in a watershed in Texas, USA. Then, 30 meter filter strips were implemented on each biofuel ropland as a mitigation method. The economical and agricultural aspect and requirements of biofuel cropping was also previously investigated. The on-site impacts estimation showed that biofuel cropping increased about 250% to 1,150% of Total Nitrogen and about 100% to 1,100% of Total Phosphorous annually. The off-site estimation at the reservoir (entire watershed outlet) showed the annual increase of 40 to 50% for both Total Nitrogen and Total Phosphorous. The on-site effectiveness of filter strips was from 58.0% to 67.9% reduction for Total Nitrogen and 57.7% to 68.2% reduction for Total Phosphorous. The filter strips reduced 28.5% of Total Nitrogen and 29.4% of Total Phosphorous at the watershed outlet.