• Journal of the Korean GEO-environmental Society
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• v.11 no.6
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• pp.69-75
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• 2010

Total suspendid solid (TSS) of non point source pollutants in construction site are in higher concentration than others (BOD, COD etc). Also, the TSS concentration is very sensitive to the rainfall intensity in early stage of construction. There are two methods for treatment of non point source pollutants, which are temporary treatment facility and filtering one. But they have disadvantages. Temporary facility system has very low efficiency and filtering system consumes high energy and takes up large footprint. This study shows how prefabricated flocculation/coagulation system is developped to cover the above weakness and evaluation of the system performance in construction site. The prefabricated flocculation/coagulation system has very high treatment efficiency comparing with temporary and filtering system and takes small footprint. Therefore, it expects that the system leads to prevention of pollution near construction site and reduction of public grievance. Proper coagulant dosage and sludge circulation facility application, controlling the height of sludge interfacial are necessary to maximize the system efficiency.

• Journal of Construction Engineering and Project Management
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• v.6 no.2
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• pp.30-39
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• 2016

This research presents the development of a self-governing mobile robot navigation system for indoor construction applications. This self-governing robot navigation system integrated robot control units, various positioning techniques including a dead-reckoning system, a UWB platform and motion sensors, with a BIM path planner solution. Various algorithms and error correction methods have been tested for all the employed sensors and other components to improve the positioning and navigation capability of the system. The research demonstrated that the path planner utilizing a BIM model as a navigation site map could effectively extract an efficient path for the robot, and could be executed in a real-time application for construction environments. Several navigation strategies with a mobile robot were tested with various combinations of localization sensors including wheel encoders, sonar/infrared/thermal proximity sensors, motion sensors, a digital compass, and UWB. The system successfully demonstrated the ability to plan an efficient path for robot's movement and properly navigate through the planned path to reach the specified destination in a complex indoor construction site. The findings can be adopted to several potential construction or manufacturing applications such as robotic material delivery, inspection, and onsite security.

• Advances in concrete construction
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• v.14 no.1
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• pp.57-70
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• 2022

The spiral case concrete (SCC) used in the underground powerhouse of large hydropower stations is complex, difficult to pour, and has high requirements for temperature control and crack prevention. In this study, based on the closed-loop control theory of "multi-source sensing, real analysis, and intelligent control", a new intelligent cooling control system (ICCS) suitable for the SCC is developed and is further applied to the Wudongde large-scale underground powerhouse. By employing the site monitoring data, numerical simulation, and field investigation, the temperature control quality of the SCC is evaluated. The results show that the target temperature control curve can be accurately tracked, and the temperature control indicators such as the maximum temperature can meet the design requirements by adopting the ICCS. Moreover, the numerical results and site investigation indicate that a safety factor of the spiral case structure was sure, and no cracking was found in the concrete blocks, by which the effectiveness of the system for improving the quality of temperature control of the SCC is verified. Finally, an intelligent cooling control procedure suitable for the SCC is proposed, which can provide a reference for improving the design and construction level for similar projects.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.15-19
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• 2009

As robotic technologies have become more actively utilized to automate many construction tasks, they have been able to improve the construction productivity, quality, and workers safety on site. A new system, of which Robot-based Construction Automation (RCA), is currently being developed, and RCA systems consist of Construction Factory(CF), Automated Bolting Robots, and Climbing Hydraulic Robot. Especially. Climbing Hydraulic robot system is very important to RCA systems because of function as lifting the Construction Factory. In this paper, We validate safety of Climbing Hydraulic Robot system before application for real building construction.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.2
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• pp.493-500
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• 2015

The importance of the air and vessel traffic control center is increasing rapidly after the recent accident of 'Sewol ferry'. Aviation, marine, and the logistics sectors are already using monitoring and control technology widely. However, the monitoring and control system for complex and dangerous construction sites operation has yet to be employed. A monitoring/control system is required for effective communication between the control center and the construction equipment fleet at a construction site, and also the exact role that notifies accurate process and identification of hazards on construction sites as needed. Therefore, this paper presents the study about communication between the construction equipment fleet and the control center through the comparison of air traffic, marine, and logistics control systems for the development of construction equipment fleet management system.

• Journal of the Korean Geosynthetics Society
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• v.19 no.4
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• pp.11-20
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• 2020

This study introduced the compact grouting method that can be used for improving soft ground and restoring buildings with unequal subsidence. The pump used in the traditional compact grouting method is a system that injects one hole each, which reduces the construction efficiency, and the analog injection method manually manages the construction by field workers, making it difficult to manage consistent quality. Pump and quality control system were developed to solve problems in existing construction. Since field supervisor determines amount of injected materials by using analog equipment and controls manually, it is difficult to manage consistent quality of construction. Therefore, the quality control system was developed in order to solve that problem. The quality control system consists of automatic mixing system of injection materials, multiple simultaneous injection pumps, and injection management monitoring system. Performance of the quality control system was verified through on-site testing, and ground improvement performance was verified through quality testing after testing and testing of the compact grouting method. Therefore, it is expected that the integrated quality control system developed will improve the quality assurance and efficiency and stability of construction at sites where construction and quality verification are difficult.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.531-538
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• 2013

The coordination and control of construction projects is vital if a project is to be a success. Almost all analysis has shown that these can only be achieved if good quality communication can be maintained on a construction site. This research focuses on the role that tablet computers could play in enhancing this communication. The following points are investigated in this paper: (a) Whether a tablet computer can enable users to monitor project progress more efficiently than traditional methods, (b) How the tablet computer fits within the project management iron triangle in construction, (c) The two different psychological impacts of information transmission for the end user using a tablet computer (i) The expectancy to transmit information frequently and rapidly from tablet computer users to project members whilst working onsite (ii) The mode of information transmission to the cognition of the transmitted information to the tablet computer. Through the use of structured interviews and questionnaires, the opinions of individuals within various disciplines in construction were canvassed. The approach adopted in this paper deals with understanding both the soft and hard issues for deploying such a system. This research enabled the authors to develop a base framework incorporating the key factors which are relevant for implementing a tablet computer based on information flows primarily.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.11
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• pp.171-180
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• 2019

This research proposed the Direct Construction System for construction corporations as a strategy intended to perform cause analysis of construction technician shortage matter and solve resulting problems, and in view of the outcomes from the application of this system to the projects and workshops, it was verified that unsteady employment, lack of career prospect, and conditions of work environment can be resolved. In addition, from corporations' perspective, it is considered that by clarifying the abovementioned three problems, fundamental complications of construction administration, quality control, safety supervision, and cost management were settled, concluding forthcoming advancement of domestic construction business quality fell far behind developed counties.

• Korean Journal of Construction Engineering and Management
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• v.10 no.5
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• pp.67-75
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• 2009

While the trend of all industries recently lies in combination, construction industry is much interested in enhancing efficiency and competitiveness in the aspect of site control by adopting RFID. Though RFID has been applied to diverse areas thus far, it cannot be easily applied to construction industry due to diverse physical, chemical and use-environmental properties of construction materials. Furthermore, it is rarely applied to the site because of many problems in its application. It is required to prepare RFID code issuance and system that can systematically control the code as well as to research the standardization of frequency, specification, protocol, package method, recognition method, etc in order to apply RFID to construction industry. In this research, RFID code issuance and management program are proposed as a part of program research to apply RFID. Furthermore, the restricted matters of existing RFID tag are drawn to produce pilot product of RFID tag that can solve it so as to perform site application test. According to the experiment, effective recognition distance varies depending on material/environmental property and control efficiency changes depending on attachment method and application method. Thus, preparing diverse restrictive factors and solutions by systematically analyzing control method(medium, process) of current architecture materials and applying it to construction site can be the way to successfully apply RFID.

• Smart Structures and Systems
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• v.30 no.5
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• pp.433-446
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• 2022

Despite efforts to reduce unexpected accidents at confined construction sites, choking accidents continue to occur. Because of the poorly ventilated atmosphere, particularly in long, confined underground spaces, workers are subject to dangerous working conditions despite the use of artificial ventilation. Moreover, the traditional monitoring methods of using portable gas detectors place safety inspectors in direct contact with hazardous conditions. In this study, a long-range (LoRa)-based wireless safety monitoring system that features the network organization, fault-tolerant, power management, and a graphical user interface (GUI) was developed for underground construction sites. The LoRa wireless data communication system was adopted to detect hazardous gases and oxygen deficiency within a confined underground space with adjustable communication range and low power consumption. Fault tolerance based on the mapping information of the entire wireless sensor network was particularly implemented to ensure the reliable operation of the monitoring system. Moreover, a sleep mode was implemented for the efficient power management. The GUI was also developed to control the entire safety-monitoring system and to manage the measured data. The developed safety-monitoring system was validated in an indoor testing and at two full-scale water pipeline construction sites.