• ETRI Journal
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• v.40 no.5
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• pp.664-676
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• 2018

Given the rapidly increasing market penetration of photovoltaic (PV) systems in many fields, including construction and housing, the effective maintenance of PV systems through remote monitoring at the panel level has attracted attention to quickly detect faults that cause reductions in yearly PV energy production, and which can reduce the whole-life cost. A key point of PV monitoring at the panel level is cost-effectiveness, as the installation of the massive PV panels that comprise PV systems is showing rapid growth in the market. This paper proposes an implementation method that involves the use of a panel-level wireless PV monitoring module (WPMM), and which assesses the cost-effectiveness of this approach. To maximize the cost-effectiveness, the designed WPMM uses a voltage-divider scheme for voltage metering and a shunt-resistor scheme for current metering. In addition, the proposed method offsets the effect of element errors by extracting calibration parameters. Furthermore, a design method is presented for portable and user-friendly PV monitoring, and demonstration results using a commercial 30-kW PV system are described.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.331-342
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• 2020

Purpose: This study concerns the cost of safety management in order to prevent accidents and disabilities in the construction industry. The purpose of the Chapter is to draw up problems and improvement measures for these safety management costs. Method: A detailed questionnaire was developed for 20 construction safety managers for the research. This questionnaire was analyzed and implemented by the Expert Group Interview (FGI) analysis method. Results: In order to understand the safety management cost system, alternatives such as preparing a standard manual, implementing regular on-site training, and establishing a monitoring system for the safety management cost were derived. In addition, there is a need to ensure autonomy in the execution of flexible costs so that they can be deployed immediately in case of emergency to improve the 'efficiency and necessity of the safety negligence system'. And it was analyzed as items that should be improved due to excessive demand for documentation. Conclusion: Through this study, problems should be recognized for the improvement of the construction safety management cost system. And it will have to come up with policy-based and institutional-improvement measures for experts.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.662-663
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• 2015

Despite the improvement of productivity and cost, the operating of such equipments yet has been recognized as a 3D business which is a low wage and poor working environment business field. Accordingly, the number of such operators has been decreasing by time. Especially, construction equipment demands higher controlling skills and occasionally involved in critical accidents. Therefore, this study aims to suggest a conceptual design for an construction equipment Around View Monitoring system that visually assists the operator for more efficient operating. It is expected that the application of such technology for a construction equipment highly improves the productivity and work quality, moreover, prevents disastrous accidents that occur to labors.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.319-327
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• 2022

Robots for construction sites, although not deeply widespread, are finding applications in the duties of project monitoring, material movement, documentation, security, and simple repetitive construction-related tasks. A significant shortcoming in the use of robots is the complexity involved in programming and re-programming an automation routine. Robotic programming is not an expected skill set of the traditional construction industry professional. Therefore, this research seeks to deliver a low-cost approach toward re-programming that does not involve a programmer's skill set. The researchers in this study examined an approach toward programming a terrestrial-based drone so that it follows a taped path. By doing so, if an alternative path is required, programmers would not be needed to re-program any part of the automated routine. Changing the path of the drone simply requires removing the tape and placing a different path - ideally simplifying the process and quickly allowing practitioners to implement a new automated routine. Python programming scripts were used with a DJI Robomaster EP Core drone, and a terrain navigation assessment was conducted. The study examined the pass/fail rates for a series of trial run over different terrains. The analysis of this data along with video recording for each trial run allowed the researchers to conclude that the accuracy of the tape follow technique was predictable on each of the terrain surfaces. The accuracy and predictability inform a non-coding construction practitioner of the optimal placement of the taped path. This paper further presents limitations and suggestions for some possible extended research options for this study.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.920-927
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• 2009

Many schedule delays and cost overruns in interior construction are caused by a lack of understanding in detailed and complicated interior works. To minimize these potential impacts in interior construction, a systematic approach for project managers to detect discrepancies at early stages and take corrective action through use of visualized data is required. This systematic implementation is still challenging: monitoring is time-consuming due to the significant amount of as-built data that needs to be collected and evaluated; and current interior construction progress reports have visual limitations in providing spatial context and in representing the complexities of interior components. To overcome these issues, this research focuses on visualization and computer vision techniques representing interior construction progress with photographs. The as-planned 3D models and as-built photographs are visualized in a 3D walk-through model. Within such an environment, the as-built interior construction elements are detected through computer vision techniques to automatically extract the progress data linked with Building Information Modeling (BIM). This allows a comparison between the as-planned model and as-built elements to be used for the representation of interior construction progress by superimposing over a 3D environment. This paper presents the process of representing and detecting interior construction components and the results for an ongoing construction project. This paper discusses implementation and future potential enhancement of these techniques in construction.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.324-327
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• 2015

Scaffold is the most commonly used equipment in various types of construction works. Since various types of construction works use the same scaffold equipment, it becomes more difficult to be controlled and managed, thus resulting hazard frequently. According to the information announced in July 2012 by Council of Labor Affairs Executive Yan, the site collapse or incomplete anti-falling protection has led the site to accident frequently, and this is the main reason that causes construction industry occupational disasters. The labor death occupational hazard ratio rises up to 13% in scaffold activity, and the Council of Labor Affairs Executive Yan has showed that the death ratio is higher when using the scaffold in construction site, the total number of death has reached to 139 from 2005 to 2010. In order to ensure the safety of scaffold user, this study tends to build a wireless sensor monitoring system to detect the reliability and safety of the scaffold. The wireless sensor technique applies in this study is different with the traditional monitoring technique which is limited with wired monitoring. Wireless sensor technique does not need wire, it just needs to consider the power supply for establishing the network and receiving stable information, and it can become a monitoring system. In addition, this study also integrates strain gauge technique in this scaffold monitoring system, to develop a real-time monitoring data transfer mechanism and replace the traditional wired single project monitoring equipment. This study hopes to build a scaffold collapse monitoring system to effectively monitor the safety of the scaffold as well as provide the timesaving installation, low-cost and portable features.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.202-203
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• 2020

Unlike price calculation by cost accounting, which categorizes costs into material costs, labor costs, and miscellaneous expenses to determine the construction budget price, construction cost calculation based on Construction Standard Unit Prices utilizes unit prices extracted from market prices of items from projects already completed to estimate costs of similar construction projects. Although unit price information is collected through construction site surveys to revise these construction standard unit prices every year, but due to the limitations of the site survey method, it is difficult to quickly implement the rapid changes in the construction methods and market prices. As such, an important issue that arose was the identification of work items whose prices need urgent revision. This study conducted research on factors that need to be considered when developing online survey system for monitoring construction site market prices. This study is expected to enhance convenience for users, and provide an efficient data collection and management system for administrators.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.50-51
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• 2014

Although price of construction equipment affects overall cost of a construction projects, the cycle of updating them presented in the Poom-Saem in Korea is more than six years. Recently there is a demand of using the 'Standard Market Price of Construction Equipment', published by the ministry of Security and Public Administration, for estimating equipment operating and ownership cost. It is urgent to introduce an advanced system for updating the prices which can timely reflect market changes.

• Korean Journal of Construction Engineering and Management
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• v.8 no.5
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• pp.191-200
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• 2007

This paper introduces a tool for predicting potential cost overrun during project execution and for quantifying the uncertainty on the expected project cost, which is occasionally changed by the unknown effects resulted from project's complications and unforeseen environments. The model proposed in this stuff is useful in diagnosing cost performance as a project progresses and in monitoring the changes of the uncertainty as indicators for a warning signal. This model is intended for the use by project managers who forecast the change of the uncertainty and its magnitude. The paper presents a mathematical approach for modifying the costs of incomplete work packages and project cost, and quantifying reduced uncertainties at a consistent confidence level as actual cost information of an ongoing project is obtained. Furthermore, this approach addresses the effects of actual informed data of completed work packages on the re-estimates of incomplete work packages and describes the impacts on the variation of the uncertainty for the expected project cost incorporating Multivariate Probabilistic Analysis (MPA) and Bayes' Theorem. For the illustration purpose, the Introduced model has employed an example construction project. The results are analyzed to demonstrate the use of the model and illustrate its capabilities.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1196-1202
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• 2007

In construction of high speed railway, the fan shape is limited to achieve reduction of required travel time and concrete railway which has structural stability and induces small maintenance cost with allowable ground settlement is recently applied. So construction of concrete railway on soft ground in which considerable ground settlement occurs increases and settlement management in soft ground section is required. Field monitoring on ground movement and integrated geotechnical information system which manages construction, design, and field monitoring data are essential for settlement management of concrete railway subgrade. Site investigation data are also required due to future repair work. Therefore in this study, integrated geotechnical information system for construction and maintenance of concrete railway is developed. The developed system consists of a database and an application program. The database contains site investigation, construction, design, and field monitoring data throughout a railway. Application program performs various functions on managing and utilizing information in the database with graphic visualization of output. And by providing integrating information with comprehensible visual displays, the applicability and effectiveness of the developed system for construction and maintenance management were confirmed.