• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.65-66
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• 2021

Due to the inexperience of stone work and field workmanship, and the preference of simple construction, various problems such as unauthorized cutting of the touch and epoxy bonding are occurring. Therefore, the existing T-type hole construction method was developed to fundamentally control these attempts. As a result of comparison with the control panel method, vibration and noise were reduced by 2dB and 10dB, indicating an excellent effect. Particularly, dust was about 1/102~1/61 in individual values, and the average value was 1/80 (12.5%). The effect of preventing damage and environmental pollution is expected to be great.

• Educational Technology International
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• v.10 no.2
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• pp.145-166
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• 2009

The purpose of this study was to investigate why advance organizers (AO) are effective in promoting comprehension and mental model formation in terms of cognitive load. Two experimental groups: a concept-map AO group and a key-word AO group and one control group were used. This study considered cognitive load in view of Baddeley's working memory model: central executive (CE), phonological loop (PL), and visuo-spatial sketch pad (VSSP). The present experiment directly examined cognitive load using dual task methodology. The results were as follows: central executive (CE) suppression task achievement for the concept map AO group was higher than the key word AO group and control group. Comprehension and mental model construction for the concept map AO group were higher than the other groups. These results indicated that the superiority of concept map AO owing to CE load decrement occurred with comprehension and mental model construction in learning. Thus, the available resources produced by CE load reduction may have been invested for comprehension and mental model construction of learning contents.

• Korean Journal of Construction Engineering and Management
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• v.1 no.4 s.4
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• pp.82-90
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• 2000

An integrated cost and schedule control is a noteworthy alternative of the separate control method which is commonly used in the domestic construction industry. In Korea, some cost and schedule integration models have been applied partly by construction managers. But, these models have not been customized yet because they did not reflect the characteristics of the domestic construction industry. This study investigates the characteristics of domestic integration models analyzed through interviews with experts who have the experiences in applying cost-schedule integration models. Based on these surveys, this study suggests the strategy for the improvement of work packaging model in the domestic construction industry.

• Korean Journal of Construction Engineering and Management
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• v.9 no.6
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• pp.185-193
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• 2008

As buildings become higher and larger, the possibility of accident also increases, and recurrent accidents and serious accidents are also increasing. However, it is not possible to control all the hazardous activities in construction site. Therefore, hazardous activities with higher possibility should be identified and prioritized in advance so engineers and managers can control the activities in safe manner. For this purpose, this research adopts FMEA technique, which has been widely utilized in manufacturing industry. In order to apply FMEA technique in construction safety management, the process of construction work is divided into sub-processes or activities. Then FMEA technique is applied to quantitatively analyze the importance of each activity from the safety perspective.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.507-510
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• 2006

Recently, the skyscrapers are increasing. There are major cost-increasing factors to management in the skyscraper construction. The more projects are large like the skyscraper construction, the more systematic methods and tools are needed for cost control. This study proposes an assessment model for major cost-increasing factors in skyscraper construction using FMEA.

• International conference on construction engineering and project management
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• 2024.07a
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• pp.1096-1102
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• 2024

Construction hoists are essential equipment for vertical lifting of workers and materials on construction sites, and their efficient operation significantly impacts the success of construction projects. To optimize hoist operation, it is crucial to accurately understand the call situation on each floor (i.e., the external waiting state) and the internal state of the hoist. This study aims to use object detection technology to monitor the status of workers and materials waiting on each floor, as well as the boarding state inside the hoist in real-time. Subsequently, by utilizing the real-time gathered information, a model was developed to reduce the number of stops, thereby demonstrating the potential of object detection technology in reducing the hoist's transportation time. The research results show that it is possible to determine the number of workers, the types of materials, and the quantity of materials to board the hoist using object detection, and to derive an optimized route. Consequently, it demonstrates that the use of object detection can reduce the transportation time of the hoist, thereby improving its operational efficiency.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.3
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• pp.188-195
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• 2009

Generally. mobile sources of air pollution were classified in on-road and non-road. Due to increased registration number of construction equipment in Korea. updated emission factors for non-road mobile sources, such as construction machinery. should be developed. NONROAD model of U.S. EPA already has introduced transient adjustment factors and sulfur adjustment factors for emission factors of diesel powered engine. In addition to this. European Environment Agency (EEA) has proposed emission factors for off-road machinery including several types of construction equipment. In this study. six types of construction equipment, such as excavator. forklift, loader, crane, roller and bulldozer, were studied to estimate emission factors based on total registration status in Korea. Total 445 construction equipments between 2004 and 2007 model year were tested with KC1-8 mode and air pollutants (CO, THC, $NO_x$, and PM) were measured. After statistical estimation and calculation, emission factors for CO, THC, $NO_x$, and PM for excavator, forklift, loader, crane, roller and bulldozer were provided and compared with previous emission factors. Moreover, updated emission factors for six types of construction equipment in this study were verified after comparison with emission factors of U.S. EPA. Finally, estimated emission amounts of four air pollutants were suggested according to six types of construction equipment.

• Journal of the Korea Institute of Building Construction
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• v.17 no.4
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• pp.369-375
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• 2017

This study suggests PSO(Particle Swarm Optimization) algorithm that optimizes the snowplow route allocation and the location of the snow control material storage to improve the efficiency in snow removal works. The modified PSO algorithm for improving the search capacity is proposed, and this study suggests the solution representation, the parameter setting, and the fitness function for the given optimization problems. Computational experiments in real-world case are carried out to justify the proposed method and compared with the traditional PSO algorithms. The results show that the proposed algorithms can find the better solution than the traditional PSO algorithms by searching for the wider solution space without falling into the local optima. The finding of this study is efficiently employed to solve the optimization of the snowplow route allocation by minimizing the workload of each snowplow to search the location of the snow control material storage as well.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.3
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• pp.299-308
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• 2011

In this study, we develop a pressure observer to measure the cylinder length of a harbor-construction robot. For the robot control, sensors are required to measure the length of a hydraulic cylinder. The cylinder-position sensor is relatively expensive when the operating environment prohibits external approaches for the measurement of the cylinder position. LVDT or linear scales are usually mounted on the outside of the cylinder, which causes poor durability on a construction site. We use a pressure sensor to indirectly estimate the length of the cylinder. The pressure sensor is mounted inside a hydraulic valve box so that it is protected by the box and easy to waterproof for an underwater robot. By treating oil as a compressible fluid, we derive the nonlinear pressure dynamics as a function of the cylinder position, velocity, and pressure. The recursive least squares (RLS) algorithm is applied to identify the dynamic parameters, and the pressure observer estimates the cylinder position through the pressure acting on the head and the rod of the hydraulic cylinder. The position accuracy is relatively low, but it is acceptable for a construction robot that handles large armor stones.

• Korean Journal of Construction Engineering and Management
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• v.12 no.4
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• pp.79-87
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• 2011

Cost control is an exceedingly fundamental and important construction business function. Even though enormous research efforts have been exerted in this area, there has been no comprehensive and quantitative study exploring detailed cost control practice of construction companies in terms of practical patterns and trends. This paper identified the variables for practical cost control process first. A survey questionnaire was developed and used in order to collect data from Korean general contractors. Survey results analyzing responses from 45 companies show that engineering aspects of cost management has recently been strongly stressed in the construction industry. Applying various types of progress measurement method are getting popular, and the level of details in collecting job site cost data are prevalent. Cost forecasting are performed more frequently. These trends indicates the recent efforts by Korean general contractors to achieve competitive advantages in the globalized market.