• Korean Journal of Construction Engineering and Management
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• v.17 no.1
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• pp.110-118
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• 2016

Construction projects are getting more complex and larger-sized with a high economic growth rate and development of new construction technologies. In addition, interests and demands on standards of construction quality are further increasing. This trend requires more systematic and a higher level of construction quality management. While the government has strengthened the regulations for quality assurance, many quality problems have repeatedly occurred mainly due to lack of recognition for quality management and quality control systems. To address this issue, this paper aims to suggest quality management improvement scheme through analyzing 3,443 nonconforming items identified during inspection of 393 construction sites from March 2012 to October 2014. The quality management improvement scheme suggested in this research is expected to prevent quality problems and defects and thus improve construction performances.

• Korean Journal of Construction Engineering and Management
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• v.15 no.2
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• pp.12-22
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• 2014

Recently, many people have been damaged seriously by construction noise. Accordingly, there have been increased the complaints and disputes. These complaints should be controlled strictly. Otherwise there could be delays or stops of project and losses of time and money. For this reasons, the Korean government is trying to convert from depending on the soundproof wall to noise control system focusing on noise sources. However, it is difficult to control the noise which is generated from construction site because construction equipment has very high noise level and construction noise generates temporarily and irregularly. Also, people do not know how much low frequency affect human body adversely because they cannot perceive low frequency noise easily. Hence, recently developed countries have conducted the research on the low frequency noise which damages on human physically and mentally. However, passive noise control is insufficient to reduce the low frequency noise, but only efficient to lower the high frequency noise. Thus, an approach which can complement limitations of passive noise control is needed. Therefore, the purpose of this research is to suggest the noise management model using active noise control on construction site. Also, ANC simulation has been conducted to examine its applicability on construction equipment. As a result, it is expected that there will be a reduction of construction noise and demages, as well as both mental and physical damages.

• Korean Journal of Construction Engineering and Management
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• v.9 no.4
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• pp.140-153
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• 2008

The recent stagnation of construction market draw more attention to construction technology development which is believed to be playing a important role in increasing the competitiveness of the construction industry. Thus, increasing pressures has been on the government playing a catalytic role of strengthen technology competitiveness. Hereupon, this study analyzed technology skill evaluation items of the Pre-Qualification system to facilitate construction technology development at the national level and tried to show the correlation between the PQ system and patent application through multilateral analysis of patent applications. Analysis results are intended to provide basic reference in decision-making process related to governmental regulation improvement especially on the PQ system. This research also attempted to draw implications to increase the use of technology related regulations such as patent & utility model based on PQ system analysis results. To do so, a comprehensive trend Analysis on the PQ system has been conducted from the view points of construction technology. Similar analysis has been done with the patent system & Utility model system. Based on Analysis result, implications of regulation improvements was outlined to promote construction technology development, due to eventually increase the competitiveness of Korean construction industry.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.789-796
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• 2003

A reliability analysis is performed to investigate the influence of the uncertainty from the limited in-situ samples and the inherent heterogeneity of the ground on the probability of piping for the marine embankment near shore. The result are compared with those of the deterministic piping stability analysis performed using the fininte element flow analysis. The random variables used are hydraulic conductivity of the ground subsurface and embankment, and the water level of both internal and external side of the embankment. The probability of piping is most sensitive to the mean and standard deviation of internal water level of the embankment among the random variables included in the reliability analysis. It is found that the lower limits of internal water level which satisfies the allowable proability of piping failure for the embankment studied were E.L(-) 1.83m and E.L(-) 1.48m during and after the construction of the embankment, respectively.

• Explosives and Blasting
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• v.17 no.2
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• pp.19-35
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• 1999

Rock fragmentation with plasma blasting technique has advantageous properties in contrast to the conventional blasting method controlling of flying rocks and ground vibrations, when residents are complaining or surrounding structures stay in protection from blasting operations. The experiences show in urban construction works that the plasma blasting is the most possible method to prevent damages and minimize adverse environmental impacts. The fragmentation energy level is evaluated by numerical simulation using PFC for various drill hole patterns and tested accordingly to get the feasibility. The energy output of plasma blasting system has been improved to a level of 1 MJ, which can break a 2-3 ㎥ granite boulder or 1.5m height bench face. Measurements are carried out to get the ground vibration level and propagation equation, so that control of the blasting operations can be performed more precisely and safely.

• Tunnel and Underground Space
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• v.7 no.4
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• pp.267-273
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• 1997

Rock fragmentation with plasma blasting technique has advantageous properties in contrast to the conventional blasting method in controlling of flying rocks and ground vibrations, when residents are complaining or surrounding structures stay in protection from blasting operations. The experiences show in urban construction works that the plasma blasting is the most possible method to prevent damages and minimize adverse environmnetal impacts. The fragmentation energy level is evaluated by numerical simulation using PFC-2D for various drill hole pattern and tested accordingly to get the feasibility. The energy output of plasma blasting system has been improved to a level of 1 MJ, which can break a 2~3 ㎥ granite boulder or 1.5 m height bench face. Measurements are carried out to get the ground vibration level and propagation equation, so that the control of the blasting operations can be performed more precisely and safely.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.13 no.4
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• pp.267-280
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• 2009

In this paper we investigate a simple two-level additive Schwarz preconditioner for the P1 symmetric interior penalty Galerkin method of the Poisson equation on rectangular meshes. The construction is based on the decomposition of the global space of piecewise linear polynomials into the sum of local subspaces, each of which corresponds to an element of the underlying mesh, and the global coarse subspace consisting of piecewise constants. This preconditioner is a direct combination of the block Jacobi iteration and the cell-centered finite difference method, and thus very easy to implement. Explicit upper and lower bounds for the maximum and minimum eigenvalues of the preconditioned matrix system are derived and confirmed by some numerical experiments.

• Journal of the Korea Computer Industry Society
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• v.4 no.10
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• pp.587-598
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• 2003

This paper construct two-level word similarity relation matrices about title and to scientific treatise. As guide keyword similarity relation matrices which is constructed to co-occurrence frequency base same time keeps recall rater by query expansion by tolerance relation, it is index structure to improve the precision rate by two-level contents base retrieval. Therefore, draw area knowledge through subject analysis and reasoned user's information request and area knowledge to fuzzy logic base. This research is research to improve vocabulary mismatch problem and information expression having essentially on query.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.969-973
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• 2007

The heavy-weight floor impact sound field of the receiving room in a testing building with bearing wall structure was investigated using bang machine and impact ball. The sound field was investigated through the impact sound pressure level distribution by the field measurement and computational analysis. Predicted sound field using the computational analysis agree with measurement result in the low frequency band. Result shows that standard deviations of the single number rating value are about 2dB in each impact source. Particularly, impact sound pressure level at 120cm height in 63Hz octave band was 5dB lower than spatial averaging value. It was found that receiving positions in the ministry of construction and transportation notice should be reconsidered.

• Journal of the Korean Society of Safety
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• v.25 no.3
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• pp.112-117
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• 2010

This study presents a methodology to evaluate the driving safety of vehicles against localized high wind on the roads over the valleys or along the coasts. Risk level for vehicle accident is derived from the side slip caused by cross wind, and then safety criteria based on reliability for driving stability are defined. The level of safety is classified according to probability of exceeding against wind speed using the concept of extreme value statistics. To attain the safety level of vehicle on bridges, numerical simulations using Computational Fluid Dynamics(CFD) are performed. Based on this result, risk reduction and quality improvement is expected through analysis for each alternative in bridges design, construction and operation & maintenance stage with proposed process