• International conference on construction engineering and project management
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• 2015.10a
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• pp.392-395
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• 2015

This study analyzes critical factors that affect issues of resolving time in BIM-based coordination using a case study. According to recent buildings that are meant to be more complex, BIM-based design coordination is regarded as an essential stage of the project delivery process. In the design coordination phase, a relocation of architectural, structural, mechanical, and electrical elements is conducted to avoid interference. In addition, the procedure of the development of each element in detail for the actual construction is carried out. Delays in coordination can affect delays in the entire delivery schedule of the project, and therefore many researches have focused on efficient coordination methods and how to shorten the period. In this study, we conducted a detailed analysis of the issue-resolving process using a case study, and found out that the participation of decision-makers for issue-resolving and the physical combination of trades affect delays in coordination time. In particular, we proposed the concept of organizational relation, indicating the level of decision-makers for issue-resolving, and the concept of physical relation, indicating the physical complexity of the issue, and we analyzed the effects of coordination delays.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.243-251
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• 2013

Cash management is a major concern for all contractors in the construction industry. It is arguable that cash is the most critical resource of all. A contractor needs to secure sufficient funds to navigate the project to the end, while keeping an eye on maximizing profits along the way. Past research attempted to address such topic via developing models to tackle the time-cost tradeoff problem, cash flow forecasting, and cash flow management. Yet, little was done to integrate the three aspects of cash management together. This paper, as such, presents a comprehensive model that integrates the time-cost tradeoff problem, cash flow management, and cash flow forecasting. First, the model determines the project optimal completion time by considering the different alternative construction methods available for executing project activities. Second, it investigates different funding alternatives and proposes a project-level cash management plan. Two funding alternatives are considered; they are borrowing and company own financing. The model was built as a combinatorial optimization model that utilizes ant colony search capabilities. The model also utilizes Microsoft Project software and spreadsheets to maintain an environment that incorporates activities, their durations, and other project data, in order to estimate project completion time and cost. Ant Colony Optimization algorithm was coded as a Macro program using VBA. Finally, an example project was used to test the developed model, where it acted reliably in maximizing the contractor's profit in the test project.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.357-358
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• 2023

Due to recent enhance of safety law and regulations in construction sites, safety inspectors have been more required in construction sites. However, most of them are novice for safety inspection which have not enough experience and skill. Therefore, the novice safety inspector's performance on hazard recognition needs to be improved for effective safety management. The performance of safety inspection is influenced by the inspector's experience and background because the inspection is usually conducted by the inspector's eyes. Therefore, there is a difference in safety inspection performance between novice and experienced safety managers. This study aims to analyze the gap of risk perception between novice and experienced safety managers using quantitative visual data. For this objective, this study conducted eye tracking experiments for novice and experienced group to evaluate cognitive performance of safety risk factors. The results provides the level of safety awareness based on their experience in construction safety. The limitation of this study is a lack of the number of samples used in this study and did not consider the various characteristics of the participants. If these limitations are supplemented in future research, it can be used to develop safety education contents for novice safety managers.

• Journal of Drive and Control
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• v.4 no.3
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• pp.47-55
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• 2007

• 한국IT서비스학회:학술대회논문집
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• 2005.05a
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• pp.418-426
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• 2005

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.104-108
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• 2005

With the improvement of living quality, people's desire for quiet living environment keeps increasing. In particular, complaints about the noise emission by constrcution equipments around residential areas take most part of the noise related complaints. In this study, based on the European Directive/20n/14/EC, noise marking obligation system for the high noise construction equipment of Europe has been reviewed to implement the similar system in Korea.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.625-626
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• 2009

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.135-136
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• 2021

This study investigated the use of different amounts of eggshell powder (ESP), namely 5%, 10%, and 15% by weight, as a substitute for Ordinary Portland Cement. The results show that its flowability and 28-day compressive strength. Meanwhile the carbon dioxide emission was though sustainable assessment analyzed It was concluded that ESP replacement level of around 5% provides the best performance to reduces environmental pollution.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.480-483
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• 2007

Recently, many apartment houses were built in nearby road and railway. Road traffic noise level and railroad traffic noise level are important factors on apartment houses inhabitant's acoustic comforts. The measurement methods which noted by Ministry of Construction & Transportation, Ministry of Environment and Korean Industrial Standard are used for measurement of exterior noise at apartment houses. The purpose of this study compare the noise level characteristic by the measuring methods and evaluating methods. The results show that road traffic noise in the daytime appeared by not greatly noise level difference by the measuring method and evaluating methods. But railroad traffic noise appeared by greatly the noise level difference by the equivalent noise level(1hour) and continuous time.

• Journal of Sensor Science and Technology
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• v.22 no.6
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• pp.421-427
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• 2013

In this paper, we introduce a new synchronous visible light communication system in which the synchronizing pulse and the data bits are simultaneously transmitted using a 3-level light signal. In the transmitter, the synchronizing pulse and the data bits modulate independently two identical visible LEDs, whose output lights add in free space, make 3-level optical signal. In the receiver, a photodiode detects the light and generates a 3-level output voltage, whose positive and negative part correspond to the synchronizing pulse and the data bits, respectively. The two signals are easily separated and recovered by a simple diode circuit. This configuration provides two independent VLC channels without any multiplexing technique, simplifies the circuit design and construction of synchronous VLC systems.