• Korean Journal of Construction Engineering and Management
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• v.14 no.4
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• pp.24-34
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• 2013

Since 2004, the government decided to gradually introduce Actual Cost Data into cost estimate for improving problems of below-cost tendering and to reflect fair market price through competition and carry contract efficiently. However, there are many concerns that Actual Cost Data has not reflected real market price, even that has contributed to reduce the government's budget. General construction firm's burden for labor cost is imputed to specialty contractors and eventually it becomes construction worker's burden. Therefore, realization of Actual Cost Data is very important factor to settle this system. To understand realization level and make short term forecast, this paper drew construction group of which labor cost constitutes more than 95% of direct cost, and compares their Actual Cost Data with relevant skilled workers's unit wage and predicts using time series analysis. The bid price which is not be reflected market price accelerates work environment changes and leads to directly affect such as late disbursement of wages, bankruptcy to workers. Therefore this paper is expected to be used to the preliminary data for solving the problem and establishing improvement of Actual Cost Data.

• Journal of Convergence for Information Technology
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• v.8 no.2
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• pp.171-181
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• 2018

The purpose of this study is to suggest the implications for maximizing the efficiency of job training conducted by companies through studying the effects of job education and training programs on job efficiency and job satisfaction. This study surveyed 300 employees of medium and large companies in Cheongju. The causality was verified based on the collected questionnaires. The results of the study are as follows. First, companies should understand the educational needs of heir employees and develop and operate employee-centered education programs. Second, companies need to have an autonomous system in order to allow voluntary application of education that can help employees to perform their duties among the external education programs. Third, companies should uncover the needs of their employees in various ways and build up the latest educational materials and educational environment to establish new knowledge and learning conditions. Finally, companies should recognize their employees as a concept of their partners and respect each employee's capabilities so that they can have autonomy and fun in their work activities.

• Korean Journal of Construction Engineering and Management
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• v.5 no.2 s.18
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• pp.162-171
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• 2004

Crack sealing is a maintenance procedure that is commonly used to reduce pavement degradation. If cracks in pavements are not sealed, surface water penetration can reduce the strength of the sub-base layers, which can result in increased deflections of the pavement. Reduced strength of the sub-base also accelerates the deterioration of the surface, due to development of greater cracking and potholes. Crack sealing is performed to reduce water and debris penetration, thereby helping to maintain pavement structural capacity and limiting future degradation. The process of sealing cracks in pavements is however dangerous, costly, and labor-intensive operation. Labor turnover and training are increasing problems related to crack sealing crews, and as traffic volumes increase. Automating crack sealing can reduce labor and road user costs, improve work quality, and decrease worker exposure to roadway hazards. The main objective of this research is to develop an automated system for sealing cracks in pavement. Extension of the algorithms and tools presented in this research is also recommended for future study.

• Journal of Navigation and Port Research
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• v.33 no.3
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• pp.181-191
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• 2009

In general, seafarer's human error is considered to be the preponderant muse for the majority of maritime transportation accidents in a merchant ship. The implementation techniques for Human Error Model (HEM) to assess possible accident risk by deck officers including captain, chief officer, second mate and third mate are described in this study. The scope of this work is focused to 642 deck officers in the ship management company with 130 vessels. At first, HEM can be constructed through the statistical analysis and expert's brainstorming process with human data to 642 deck officers. Then the variables $\upsilon$ for the human factors, the evaluation level EP($\upsilon$) for $\upsilon$, the weight $\alpha$ of $\upsilon$, and the title weight $\beta$ of each deck officers can be decided. In addition, through the analysis of ship's accident history, the accident causation ratios by human error ${\gamma}_H$ and by external error ${\gamma}_B$ can be found as 0.517(51.7%) and 0.483(48.3%), respectively. The correlation coefficients to $\upsilon$ are also shown significant for a 95% confidence interval (p < 0.05) for each coefficient. And the validity of HEM is also surveyed by the analysis of normal probability distribution of risk level RL to each deck officer.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.17-28
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• 2010

A climbing lane is installed to separate low-speed traffic from high-speed traffic if drastic traffic capacity reduction is expected due to a large number of vehicles that slow down in the upward section. Existing studies on climbing lanes have focused on the designation, location of starting and ending points, and installation method of climbing lane with regard to road design standards. However, in terms of traffic operation, it was known that the climbing lanes cause traffic congestion due to the increase of traffic volumes. In this regard, this study aims to establish traffic operational guidance as to how much effects temporary closure of climbing lanes can have on traffic improvement according to the volume-capacity ratio, grade, and composition of trucks. A test section of simulated climbing lane was selected in Nakdong JC bound for Masan(136.9K~133.3K, 3.6km, 3.7%) on Jungbunaeryuk expressway to conduct VISSIM analyses, microscopic traffic simulation based on such control variables as traffic volume(v/c), grade and the trucks ratio. As a result of the analyses, it has been found that v/c and the ratio of trucks are the key variables for efficient traffic management of climbing lanes in order to relieve traffic congestion via climbing lane. If ratio of trucks are more than 50% and when v/c would be 0.8, both climbing lane would be closed and non-operated regardless of grade and ratio of trucks when v/c is 1.0. With the increased traffic due to a five-day work week system, continued peak hours during the weekday, increased and various patterns of congestion on expressway, this study would be expected to contribute to facilitating researches on flexible operational standards for road facilities.

• Korean Journal of Construction Engineering and Management
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• v.21 no.4
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• pp.82-89
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• 2020

Article 64 of the Enforcement Decree of the National Contract Act The requirement of the pre-amendment statute related to the adjustment of the contract price was 5% or more of the price fluctuation rate from the date of the contract. However, the meeting requirement was changed from 5% or more to 3% or more from the date of signing of the Presidential Decree No. 19035 to 2005. 9. 8. The method of adjusting the contract amount was also changed to determine the contractor's desired adjustment method at the time of contract. Alleviating these requirements and revising the empowerment of contract partners is intended to prevent difficulties in achieving smooth objectives by applying to public construction contractors without unfairly benefiting or unfavorable to contract partners. Even if the standards are relaxed and the rights are secured as described above, if the existing provisions for the adjustment of price fluctuation are applied, unlike the original purpose of the government system, the Korea Bank's price economic statistics classification method and the contract construction classification criteria applied in public construction work Due to the inconsistency, it can be seen that the amount of adjustment for price fluctuation by construction type is excessive and underestimated. Therefore, the purpose of this study is to analyze problems through cases and to make appropriate construction cost adjustment through improvement measures.

• Korean Journal of Construction Engineering and Management
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• v.21 no.4
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• pp.21-29
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• 2020

This study analyzed problems of operating performance bond for public works and derived some suggestions for improvement. The Contract Law for Government Owner requires to submit performance bond which guarantees performing the construction contractor pays back compensation money when the obligation is not executed. Currently, first bid eligibility for participation is exactly required for executing company of performance bond obligation, not considering volume, technical level, and special type of remaining works. In collaboration contract, if guarantee accident occurs, it is obliged for remaining collaboration contractors to be qualified to fulfill the whole contract. This study proposes following improvement plan to solve problems of current performance bone in public works. Firstly, qualification criteria must be deregulated exceptionally for selecting proper contractor, which executing performance bond obligation, considering progress and characteristics of remaining works. Secondly, In collaboration contract, the prerequisite of remaining contractors' should be deregulated as 'implementation requirement of the remaining works'from'implementation requirement of the whole work'. Finally, defect responsibility should be included in liabilities of performance bond by specifying that owner or guarantee agency bear them.

• Korean Journal of Remote Sensing
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• v.26 no.5
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• pp.571-580
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• 2010

Coastal shoreline movement due to erosion and deposition is a major concern for coastal zone management. Shoreline is changed by nature factor or development of coastal. Change of shoreline is threatening marine environment and destroying. Therefore, we need monitoring of shoreline change with time series analysis for coastal zone management. In this study, we analyzed the shoreline change using airphotograph, LiDAR and satellite imagery from 1971 to 2009 in Uljin, Gyeongbuk, Korea. As a result, shoreline near of the nuclear power plant show linear pattern in 1971 and 1980, however the pattern of shoreline is changed after 2000. As a result of long-term monitoring, shoreline pattern near of the nuclear power plant is changed by erosion toward sea. The pattern of shoreline near of KORDI until 2003 is changed due to deposition toward sea, but the new pattern toward land is developed by erosion from 2003 to 2009. The shoreline is changed by many factors. However, we will guess that change of shoreline within study area is due to construction of nuclear power plant. In the future work, we need sedimentary and physical studies.

• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.423-431
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• 2017

This study analyzed the educational background, career, and post-retirement activities of notable bureaucrats employed at Chosun Railway Bureau during the Japanese colonial period in Korea. First, significantly, most railway bureaucrats were of Japanese origin, being specialized in railway operations and adjusted to occupation in a reserved organizational environment for a considerable time period. Second, the Japanese showed explicit eagerness to work at the Chosun Railway, which fitted their ideology of railway bureaucrats. In addition, almost 60% of the bureaucrat population had strong educational experience from Tokyo Imperial University, which is equal to the percentage of graduates from other institutions operating during the Japanese colonial period. Moreover, in the very early period of building the railway system, the demand for specialists was higher than for other jobs and divisions because of the railroad's complex infrastructure, which resulted in high job appointment rates. In a similar sense, based on a strong affiliation of bureaucrats with railways, the number of bureaucrats from Japanese Railway Worker's Bureau was higher initially because of bureaucrats from South Manchurian Railway Company. These changes essentially contributed to alteration of bureaucrats' awareness and created a more positive attitude regarding the Chosun Railway. In the meantime, as opposed to the Taiwan and Manchurian Railways, both Chosun Railway and the Taiwan Railway were operated in compliance with strong bureaucratic traditions.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.4
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• pp.413-418
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• 2020

It is necessary to manage the prediction accuracy of the machine learning model to prevent the decrease in the performance of the grid network condition prediction model due to overfitting of the initial training data and to continuously utilize the prediction model in the field by maintaining the prediction accuracy. In this paper, we propose an automation technique for maintaining the performance of the model, which increases the accuracy and reliability of the prediction model by considering the characteristics of the power grid state data that constantly changes due to various factors, and enables quality maintenance at a level applicable to the field. The proposed technique modeled a series of tasks for maintaining the performance of the power grid condition prediction model through the application of the workflow management technology in the form of a workflow, and then automated it to make the work more efficient. In addition, the reliability of the performance result is secured by evaluating the performance of the prediction model taking into account both the degree of change in the statistical characteristics of the data and the level of generalization of the prediction, which has not been attempted in the existing technology. Through this, the accuracy of the prediction model is maintained at a certain level, and further new development of predictive models with excellent performance is possible. As a result, the proposed technique not only solves the problem of performance degradation of the predictive model, but also improves the field utilization of the condition prediction model in a complex power grid system.