• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.1091-1104
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• 2018

Wear prediction of TBM disc cutters is a very important issue during design as well as construction stages for hard rock TBMs as the cutter head intervention is directly related to the time and cost of tunneling. For that, some methods such as NTNU, CSM and Gehring models were used to predict disc cutter wear and intervention interval. There are however some problems to be addressed in these models in terms of accuracy and time for testing, so that a NAT (New Abrasion Tester) model has been developed in order to achieve simplicity and reliability together at the same time (Farrokh and Kim, 2018). On the basis, the proposed NAT model has been applied to ${\bigcirc}{\bigcirc}$ project in Korea. A comparative study was performed to compare with the conventional methods and as a result the NAT model showed a very good agreement with actual cutter life. The NAT model will be further applied to other projects to establish credibility.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.423-438
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• 2021

The blade of motor grader is used for scattering and leveling the aggregates on the foundation of road construction site. The paper performed a design improvement research of the blade part to enhance the working efficiency of motor graders. The scattering works of aggregates by blade driving were simulated by DEM (discrete element method) of a dynamic code. The four design parameters were selected and a specific leveling scenario for the simulation was determined. The nine blade models were numerically experimented, and the sensitivity of each factors was analyzed. Next, the design factors that influence a blade performance have been selected by ANOVA, and these key design factors were applied to the progressive quadratic response surface method (PQRSM). The optimum set of design factors of the blade was finally proposed.

• Magazine of RCR
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• v.4 no.4
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• pp.27-33
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• 2009

• Magazine of RCR
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• v.4 no.1
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• pp.17-25
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• 2009

• Magazine of RCR
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• v.7 no.3
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• pp.24-26
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• 2012

• Korean Journal of Construction Engineering and Management
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• v.13 no.5
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• pp.125-134
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• 2012

In the construction industry, "Green" is emerging as a keyword of new growth engine. Since green construction competitiveness is essential for contractors' survival and growth, it is important to understand what constitutes green construction competitiveness. The objective of the study is to identify elements of green construction competitiveness and to discuss relationships between their importance and current level based on the Gap analysis. A better understanding of the elements of green construction competitiveness assists contractors in formulating green strategies. It also provides insight into what motivates contractors in establishing related policies and regulations. The study identifies that in general there exists a gap between the importance and current level of green construction competitiveness. It also demonstrates that CEO' competence shows a less gap between the importance and current level but firms' competence is an area of weakness. Finally a substantial gap is observed in the field of green R&D strategies and sub-contracting partners.

• Korean Journal of Construction Engineering and Management
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• v.15 no.4
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• pp.58-67
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• 2014

The proportion of investment in national R&D projects in construction and transportation has been increasing continuously; in terms of the size of R&D projects, there are many medium- to large-sized projects of over KRW 10 billion. However, in spite of such continuous increase in R&D investments, there are many technologies developed but not commercialized, i.e., the quiescence of technology. Accordingly, it is necessary to link the R&D results to commercialization by expanding the scope of R&D projects. In this context, this study presented objective reference prices to be used in contracting/transacting technology and implementing commercialization strategy by conducting technology valuations against on-going research projects with earnings approach, and by estimating value of patented technology. Sum of free cash flow (business value) that can be generated during the life of the technology was estimated as KRW 512 million by reflecting a discount rate of 16.34% to convert it into the present value. In addition, the technology value was computed as KRW 227million by applying a technology factor of 44.39% to the above value. Based on the technology value estimated in this way, it is necessary to establish industrialization and commercialization strategy of the technology.

• Tunnel and Underground Space
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• v.32 no.5
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• pp.298-311
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• 2022

Some problems, such as aging workers, a decreased population due to a low birth rate, and shortage of skilled workers, are rising in construction sites. Therefore research for smart construction technology that can be improved for productivity, safety, and quality has been recently developed with government support by replacing traditional construction technology with advanced digital technology. In particular, the motor grader that mainly performs road surface flattening is a construction machine that requires the application of automation technology for repetitive construction. It is predicted that the construction period will be shortened if the construction automation technology such as trajectory tracking, automation work, and remote control technology is applied. In this study, we introduce the hardware and software architecture of the smart motor grader to apply unmanned and automation technology and then analyze the traditional earthwork method of the motor grader. We suggested the application plans for the path pattern and blade control method of the smart motor grader based on this. In addition, we verified the performance of waypoint-based path-following depending on scenarios and the blade control's performance through tests.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.462-467
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• 2001

There are growing interests for knowledge-based information to build up competitiveness both in public and in private. Construction industry compared to other industries, shows strong knowledge usages in products and process. R&D investment over the construction industry has been decreased since economic crisis (IMF), so technology status of domestic construction industry has gap of 4.6 years with developed countries. Information infra also lowers in use of information and investment than other industries. In case of knowledge management, usage of information technology and vision establishment show high status but knowledge sharing and evaluation stay in low level. For the administration of knowledge-based information, there are needs of continuous R&D investments, educations for inspiring employees to knowledge share, systems for knowledge estimation and evaluation, and organizational culture.

• Magazine of RCR
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• v.5 no.1
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• pp.33-40
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• 2010