• 월간 기계설비
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• s.17
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• pp.96-99
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• 1991

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.1
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• pp.9-20
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• 2023

For highway concrete structures, the deterioration of the structure is accelerated due to the increase in the use of deicing materials, and sectional repair work is being frequently carried out to restore performance. However, after the repair work, re-damage such as cracks, delamination, and poor bond performance is exhibited in the repaired sectional area. In this study, overseas repair material requirements were first analyzed, and present domestic requirements were improved repair material performance through field surveys of common concrete structures, laboratory experiments, and test construction on a disused concrete bridge. In addition, performancebased quality requirements were presented so that all materials that meet the required performance can be applied, and different test methods for each material were unified into concrete test methods for consistent test results analysis. The considered performance requirements were compression strength, bending strength, and bond strength for structural properties, and length change rate, crack resistance, thermal expansion coefficient, and elasticity coefficient were for dimensional behavior. For resistance to chloride penetration resistance and freeze-thaw resistance were presented as durability. The proposed requirements for concrete repair materials are expected to contribute to the improvement of the quality of concrete sectional repair work in Korea.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.2
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• pp.177-188
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• 2021

On December 2015, Financial Supervisory Service(FSS) announced the four key thematic audit review areas, one of them is an appropriation of unbilled revenue. Accounting of unbilled revenue is intertwined with a percentage of completion, that is concerned about discretionary decision by manager. Therefore, if manager motivated by income-increasing manipulation is exaggerating percentage of completion, unbilled revenue is excessively recognized. This problem is caused the serious accounting issues(e.g., shock at a loss for 2013 fiscal year by some construction firms, malpractice of accounting in order-made production industry). Distrust of accounting was grown because the shipbuilding and construction industries successively went poor management and bad accounting of them is revealed. Those accounting issues were the trigger for problem recognition of unbilled revenue, they were background for the designation of appropriation unbilled revenue as thematic audit review areas by FSS. Therefore, this study verified effectiveness of thematic audit review by empirically analyzing whether designation of thematic audit review makes the firm increases conservative behavior. Conservative accounting is estimated by using Basu(1997) model. We analyzed the effect of the thematic audit review on conservative accounting of unbilled revenue by comparing with reflecting unbilled revenue or not. The sample for test consists of firm-years the manufacturing and construction industries from 2012 to 2017. The test results of this study suggested that the conservative accounting of unbilled revenue after designation of the thematic audit review was significantly increased. We also tested again by classifying whether or not it is construction industry. We found that construction industry is more conservative than the other industry only for the designated year of the thematic audit review, otherwise there was not any evidence for significantly increasing conservatism. This study contributes to the literature by empirically analysing relationship of the unbilled revenue to the thematic audit review from the perspective of the conservatism and verifying effectiveness of the thematic audit review.

• Korean Journal of Construction Engineering and Management
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• v.21 no.6
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• pp.16-26
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• 2020

Road Pavement Maintenance Work is generated in a variety of different field conditions, and it is difficult to calculate the construction cost because there are no detailed criteria when preparing the estimated construction cost. Unlike new pavements, Road Pavement Maintenance has to be constructed with operating vehicles, and there are many differences in productivity depending on urban areas, limited work hours, night-time, construction area, etc. To compensate for this, the standard for calculation of construction cost provides additional charges for the number of lanes, residential areas, working hours, and night work, but it applied differently depending on construction officials. In this study, construction cost estimation standards that can properly reflect the conditions of the site was investigated for major types of Road Pavement Maintenance work. The site was investigated and analyzed mainly for many construction sites with 'overlay of asphalt after cutting', 'restore surface', 'repair of pavement', and 'recovery of roadway'. The criteria for the application of construction volume separately according to working hours, public places, and land area including extra charges for basic downtown and residential area. The hours of operation were divided into three types(7 hours, 5 hours, 3 hours) excluding movement and preparation time, and each type provided a coefficient for dividing the area of the construction site into five types. The construction cost calculation method based on the construction purpose is site conditions is proposed accordingly, and it is deemed that a plan for the designer to calculate the construction cost has been prepared in consideration of the site conditions.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.9
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• pp.359-366
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• 2021

A number of construction companies in Korea invest considerable human and financial resources to construct a system for managing apartment defect data and for categorizing repair tasks. Thus, this study proposes machine learning models to automatically classify defect complaint text-data into one of the sub categories of 'finishing work' (i.e., one of the defect repair tasks). In the proposed models, we employed two word representation methods (Bag-of-words, Term Frequency-Inverse Document Frequency (TF-IDF)) and two machine learning classifiers (Support Vector Machine, Random Forest). In particular, we conducted both binary- and multi- classification tasks to classify 9 sub categories of finishing work: home appliance installation work, paperwork, painting work, plastering work, interior masonry work, plaster finishing work, indoor furniture installation work, kitchen facility installation work, and tiling work. The machine learning classifiers using the TF-IDF representation method and Random Forest classification achieved more than 90% accuracy, precision, recall, and F1 score. We shed light on the possibility of constructing automated defect classification systems based on the proposed machine learning models.

• 한국도로학회지:도로
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• v.2 no.1
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• pp.79-84
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• 2000

• Journal of Korean Association for Spatial Structures
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• v.3 no.4 s.10
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• pp.23-35
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• 2003

• Environmental engineer
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• v.19 s.203
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• pp.70-71
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• 2003

• 어항어장
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• s.99_100
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• pp.76-79
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• 2012

• Korean Architects
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• v.1 no.1
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• pp.17-20
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• 1966