• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3D
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• pp.457-468
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• 2011

Recently, the non-vibration mass excavation method is used on sewage pipes and road construction sites in Jeju. However, a construction cost estimation based on the unit quantity does not provide a proper unit price. In this study, a comparison of the productivity of the standard quantity-per-unit costing method and the one of the work crew combination method was made based on the site monitoring of the non-vibration mass excavation method that is used in construction sites near Jeju. For this, data of 35 sites were collected: a regression equation was derived from the 30 data, and verification was carried out through the remaining 5 data. The analysis concluded that a day's workload is $16.43m^3$. In addition, a combination of the equipment considering the site conditions and the amount of labor, which varies with the number of work crew was obtained in order to estimate the construction cost of the work crew combination method. The construction cost was calculated based on the one-day workload ($16.43m^3$) derived from the regression analysis. The cost then was analyzed and compared with the standard quantity-per-unit costing method.

• Korean Journal of Construction Engineering and Management
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• v.21 no.3
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• pp.39-47
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• 2020

There are two kinds of cost estimate system in construction in china. Quota valuation model is a traditional cost estimate system under the unity of quantity and price, which is easier and has been used for decades. But the Quota valuation model becomes increasingly unsuited to the needs of society with the development of market economy. To meet the needs of China's market economy development and construction works in the field of international cooperation, the Bill of Quantities valuation model was introduced in 2003. However, there are still many shortcomings and deficiencies in the course of implementation of Bill of Quantities valuation model. In addition, interest in the Chinese construction market continues to increase in Korea due to the recent new North Korean policy and China's the Belt and Road policy. This paper aims to examine the cost estimate system of public construction works in China, and to provide basic data for deriving future improvement plans by comparing and analyzing it with standard cost estimate system in Korea.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.7
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• pp.49-57
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• 2019

Recently, the use of deep deck plate has been increased in various structures, such as underground parking lots, logistics warehouses, because it can reduce construction periods and labor costs. In this study, a newly developed Double Deck (D-deck) plate which can leads to save story heights has been introduced, and experimental tests on a total of five D-deck plates under construction loads have been carried out to investigate their structural performance at construction stage. The loads were applied by sands and concrete to simulate the actual distributed loading conditions, and the vertical deflection of D-Deck and the horizontal deformation of web were measured and analyzed in detail. As a result, it was confirmed that all the D-decks showed very small vertical deflection of less than 5.34 mm under construction loads, which satisfies the maximum deflection limit of L / 180. In addition, the D-Deck plate was found to have a sufficient rigidity to resist construction loads in a stable manner.

• Journal of the Korean Geographical Society
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• v.51 no.4
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• pp.525-539
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• 2016

This study attempts to predict the changes in the spatial distribution of occupational employment in Korea by applying Markov Chain Model. For the purpose we analyze the job-related migration pattern and estimate the transition probability with the last six years job-related migration data. By applying the Chapman-Kolmogorov equation based on the transition probability, we predict the changes in the spatial distribution of occupational employment for the next ten years. The result reveals that the employment of professional jobs is predicted to increase at every city and region except Seoul, while the employment of elementary labor jobs is predicted to increase slightly in Seoul. In particular, Gangwon-do and Chuncheongdo are predicted to increase in the employment of all occupational jobs.

• Korean Journal of Construction Engineering and Management
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• v.12 no.5
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• pp.103-116
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• 2011

Crack sealing is a maintenance technique commonly used to prevent water and debris penetration and reduce future degradation in pavement. In recent years, several systems for automatically routing and sealing pavement cracks have been developed in the highway construction and maintenance area. Automating pavement crack sealing can improve safety, productivity and quality, and reduce road user cost as well. The reduction in crew size and the increase in productivity of the automated sealing process will be translated directly into significant potential cost savings. The main objective of this study is to illustrate conceptual models for the development of the automated pavement crack sealer which meets domestic road condition and regulation, and to discuss its technical feasibilities. Conclusions are made concerning the applicability and the value of cantilever-typed pavement crack which is selected as the most feasible alternative in both economical and technical aspects.

• Journal of Korean Society of Forest Science
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• v.101 no.4
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• pp.729-736
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• 2012

Korea Forest Service is recently focused on forest tending works for promoting in green jobs. The purpose of forest tending work is not only maintaining ecologically stable forest stand structure but also developing commercial forest. These trends are also emphasized by creation of various benefits and expanding carbon absorption in forest management. For achieving these purposes, Management efficiency of output was analized by the inputs such as labor cost, material cost and expense cost using DEA technique. The results show that, 19 sub-compartments are appeared to be the optimal in the efficiency of the forest tending works among total 52 sub-compartments. Among those there were 5 sub-compartment 8-0-3, 9-3-3, 6-0-3, 7-0-6, 1-0-5 and 3-0-3 to be considered in the high reference. The high reference areas mean those areas which is well accomplished in forest tending works as the desirable model.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.2
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• pp.267-275
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• 2023

As aged infrastructures have been increased, the importance of accurate maintenance costs and proper budget allocation for infrastructure become prominent under limited resources. This study proposed a mapping algorithm between representative defects, repair methods, and the estimated maintenance costs for concrete bridges. In this regard, using BMS (Bridge Management System) data analysis, bridge repair methods were classified and matched with defects according to their locations, types, and sizes. In addition, the maintenance costs were estimated based on the amount of work-load and quantity per unit using CSPR (Cost Standard Production Rate). As a result, the level of accuracy was an average of 85.1 % compared with the actual bill of quantity for Seoul bridge maintenance. The accuracy of maintenance costs is expected to be enhanced by considering the various site conditions such as pier height, extra charge conditions, additional equipment, etc.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.2
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• pp.205-213
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• 2010

This study was to analyze the past regime's real estate policy and the time-series data on real estate price index from 1986 to 2009 in 24 years. Also, the real estate index and macroeconomic variables, the impact on house price index variable conducted to regression analysis and to analyze whether and how much is affected. Analyzed as follows: First, Korea's real estate policy was the post-policy and the past regime's real estate policy was inconsistent with each other. Second, in the normal phase whenever real estate issues, the measures of the strengthening regulation and of the economic recovery were only to repeat periodically. Third, the timing and means of policy enforcement was an inappropriate and Real estate market was getting worse at the time whenever a real estate policies performed. Fourth, The apartments prices index of the housing types rose the highest and were the most popular for 24 years. Increase or decrease the amount of the price index for apartments, Roh Tae-woo(65.0%) - Kim Dae-jung (42.5%) - Roh Moo-hyun (32.8%) were in order. Fifth, the results of the regression analysis carried out: The impact on housing prices among independent variables were followed by Cap Construction- one per capita income - Housing consumer price index - Accompanying Composite Index - Trailing Composite Index - Home subscription Subscriber account - Leading Composite Index.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.4073-4081
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• 2012

This study was designed to estimate the prevalence of arthritis and to identify subgroups with high prevalence rates of arthritis. Study subjects were 18,406 Korean adults aged 19 and more from the 4th (2007-2009) Korea National Health and Nutrition Examination Surveys data. Annual self-reported prevalence and its rate ratios by demographic and behavioral factors were calculated using SAS 9.2 with survey procedure. The result was as follows. The crude prevalence of arthritis was 11.7% (osteoarthritis 10.2% and rheumatoid arthritis 1.7%). The prevalence was increased by age strata (2.4% in 19-44 aged, 16.4% in 45-64, 38.3% in 65 and more). After adjusting for age, we found the subgroups with high prevalence: older people, women, residents in non-apartment area, separated and divorced people, people with low education, people with several occupations (agricultural and fishery workers, elementary occupations, and unemployed), people with low household incomes, people with medical aid, and people with higher BMI. Those subgroups may be target populations in community health programs to control the disability from arthritis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.4
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• pp.1289-1298
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• 2014

Pavement crack sealing method, which is one of the methods to maintain and repair the road, prevents the extending of cracks by repairing cracks in its early occurrence and has already been applied to many roadworks in advanced foreign country for a long time. But in the conventional crack sealing method, traffic accidents occur frequently during the repair because it's commonly performed on the heavy traffic road or highway. It also has some difficulties in securing the safety of workers from the risk of burns caused by heated sealant. In an effort to solve these problems, automated pavement crack sealing machines such as ARMM, OCCSM, TTLS have been developed in advanced foreign country since early 1990s. Also APCS in 2004 and ACSTM in 2013 were already developed domestically. However, since these automated crack sealers developed from a number of research institutions have different test-bed conditions and productivity measurement models, it's difficult to compare and evaluate them objectively. In this study, the image processing time of the respective machines and the movement time of each motion on the work process were estimated by using fully autonomous mapping and semi-automatic mapping in order to measure the productivity in the same environmental conditions. In addition, the productivity measurement test-bed reflected domestic road characteristics was designed to estimate and compare the productivity of the automated crack sealing machines.