• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.500-507
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• 2022

COVID-19 pandemic forces college education to be rapidly switched from face-to-face education into remote education. Two inconsistent findings exist in previous study about remote learning. First, studies before COVID-19 pandemic found remote learning is an effective method, which provided students with higher achievement and improved their work-life balance. However, studies showed remote learning during COVID-19 pandemic is not as effective as expected because of technical issues, lack of motivations and even mental health issues. Second, findings from studies about remote learning impacts on workload and productivity during COVID-19 are also inconsistent. Therefore, this study aims to quantitatively measure college students' workload and productivity during COVID-19 of different types of tasks to provide a comprehensive and latest evaluation on remote learning. The findings of this study show remote learning slightly increases college students' total listening and speaking tasks workload, total reading and writing tasks workload. Furthermore, phone call, in-person meeting, online meeting and email workload increase significantly in remote learning. However, productivity for both listening and speaking, reading and writing tasks decreases after remote learning but no significant changes of productivity are found.

• 한국산업융합학회 논문집
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• 제26권6_3호
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• pp.1325-1332
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• 2023

Recently, much research is being conducted based on point cloud data for the growth of innovations such as construction automation in the transportation field and virtual national space. This data is often measured through remote control in terrain that is difficult for humans to access using devices such as UAVs and UGVs. Drones, one of the UAVs, are mainly used to acquire point cloud data, but photogrammetry using a vision camera, which takes a lot of time to create a point cloud map, is difficult to apply in construction sites where the terrain changes periodically and surveying is difficult. In this paper, we developed a point cloud mapping system by adopting non-repetitive scanning LiDAR and attempted to confirm improvements through field application. For accuracy analysis, a point cloud map was created through a 2 minute 40 second flight and about 30 seconds of software post-processing on a terrain measuring 144.5 × 138.8 m. As a result of comparing the actual measured distance for structures with an average of 4 m, an average error of 4.3 cm was recorded, confirming that the performance was within the error range applicable to the field.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.880-885
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• 2007

최근 건설공사가 대형화 및 복잡화됨에 따라 시공 과정에 사용되는 자원의 종류가 다양해지고 그 수가 증가하였다. 이에 따라 건설 현장에서의 자원관리는 건설 공사의 성공에 영향을 미치는 중요한 요소로 작용하고 있으며 다양한 기술을 통한 자원관리의 효율화가 적극적으로 추진되고 있다. RFID 기술과 센서 네트워크와의 결합을 통한 RFID/USN 연동시스템은 자원관리의 자동화 및 실시간 정보 네트워킹을 가능하게 하여 각종 시설 및 자원들을 효과적으로 관리할 수 있게 한다. 현재까지 건설 산업에서의 대부분의 RFID 기술에 관한 연구는 바코드를 대체할 수 있는 자원인식기술에 한정되어 왔다. 따라서 본 연구는 효과적인 자원관리를 위한 RFID/USN 연동시스템을 건설 현장에 적용하기 위해 RFID/USN의 기술적 특성 및 한계를 파악하여 건설 현장의 적용성을 검증하고자 한다. 이를 위하여 거리 및 각도에 따른 RFID/USN 연동시스템의 인식률과 건설 현장의 주요 자재에 따른 인식률을 실험하고 그에 따른 분석 결과를 제시하였다.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.1242-1242
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• 2022

Annually, several construction workers fall ill, are injured, or die due to heat-related exposure. The prevalence of work-related heat illness may rise and become an issue for workers operating in temperate climates, given the increase in frequency and intensity of heatwaves in the US. An increase in temperature negatively impacts physical exertion levels and mental state, thereby increasing the potential of accidents on the job site. To reduce the impact of heat stress on workers, it is critical to develop and implement measures for monitoring physical exertion levels and mental state in hot conditions. For this, limited studies have evaluated the utility of wearable biosensors in measuring physical exertion and mental workload in hot conditions. In addition, most studies focus solely on male participants, with little to no reference to female workers who may be exposed to greater heat stress risk. Therefore, this study aims to develop a process for objective and continuous assessment of worker physical exertion and mental workload using wearable biosensors. Physiological data were collected from eight (four male and four female) participants performing a simulated drilling task at 92oF and about 50% humidity level. After removing signal artifacts from the data using multiple filtering processes, the data was compared to a perceived muscle exertion scale and mental workload scale. Results indicate that biosensors' features can effectively detect the change in worker physical and mental state in hot conditions. Therefore, wearable biosensors provide a feasible and effective opportunity to continuously assess worker physical exertion and mental workload.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.387-388
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• 2023

PHC pile head cutting is an essential work in pile foundation construction. However, since the work has labor-intensive characteristics, there are problems such as productivity and safety. So in previous study PHC pile one-cutting head cutting automation equipment was developed to solve this problem. However, it has been investigated as a limitation that checking the cutting position of the PHC pile can be challenging in place where a rotary laser leveler cannot irradiate cutting position, as the sensing unit of the developed automated equipment utilizes an optical method. Therefore, the objective of this study is to delvelop a GNSS-based methodology for sensing the cutting position of PHC piles to overcome the limitations of the optical method and to examine its feasibility for field application. If the proposed methodology is applied to the construction site, it is expected that the convenience and productivity of the PHC pile cutting position sensing work will be improved.

• 드라이브 ㆍ 컨트롤
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• 제21권1호
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• pp.53-58
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• 2024

With the recent development of intelligence and automation technologies for construction machinery, the demand for safety and efficiency of road-cutting operations has continued to increase. In response to this, a double-blade road cutter has been developed that can automatically cut roads. However, a double-blade road cutter has a load difference between the two blades due to the ground and wear conditions of the cutting blades. The difference in load between the two blades distorts the direction of travel of the cutter. In this study, a vision sensor-based driving guide technology was developed to correct the driving path of road cutters. In addition, we developed a load-sensing technology that detects blade loads in real-time and controls driving speed in the event of overload.

• 유공압시스템학회:학술대회논문집
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• 유공압시스템학회 2010년도 춘계학술대회
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• pp.62-65
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• 2010

Field robot represented by excavator can be applied for various working in manufacturing, construction, agriculture etc. Because of the flexibility of its multi-joint mechanism and the high power of hydraulic actuators. Since the excavator operates in the hazardous working circumstance, operators exposed in harmful environment. Therefore, automation system has been investigated to protect from the harmful environment. In this paper, the method to construct the remote control system is proposed. The remote control system is consisted of a manual and auto mode. Manual mode controls a hydraulic cylinder as open loop control. and auto mode controls the end effecter of excavator using tracking control system. The efficiency of remote control system was evaluated through the field test.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.418-425
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• 2022

For a commercial building, property managers play an important role in maximizing the benefit by reducing cost and increasing revenue in the operation and maintenance phase of the building. However, most of property managers are spending their time in monitoring facility managers who have little impact on cost reduction and maximization of operating profit. The industry practitioners have difficutlty in increasing the efficiency of thier work due to this work environment. In addition, both property managers(PMr) and facility managers(FMr) are dependent on the paper drawings and manuals, which can worsen the inefficiency and human errors are inevitable. This study aims to contribute to improvement of the current practice by developing a novel algorithm that autmatically links the facility information with 3D model, which can provide an efficient property management for commercial buildings.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.177-178
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• 2022

As part of the study on the development of the setting time estimation system, this study attempted to confirm the change in hardness values for each influencing factor variable and secure its reliability. According to the research results of this paper, the hardness value of the setting time estimation system tended to gradually decrease in the case of the hardness value of the closing time by curing temperature, and the hardness value increased in the concrete state compared to mortar. Therefore, further research on influencing factors will be conducted in consideration of material and statistical factors in the future.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 2부
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• pp.89-90
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• 2011

External wall cleaning is a task that is currently being performed by human workers. The recent surge in the number of high-rise buildings has led to such problems as difficulties in cleaning the wall, high risk to the specialized workers, and increased maintenance expenses. As a fundamental measure to perform external wall cleaning work in a safer manner, automation/mechanization has been on the rise. This research aims to classify façade types and analyze the performance requirements of a wall-cleaning robot, as preliminary research to develop a wall-cleaning robot. The replacement of specialized workers with robots is expected to improve both safety for workers and quality of cleaning.