• International conference on construction engineering and project management
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• 2013.01a
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• pp.592-595
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• 2013

Advent of Wireless Sensor Networks (WSN) has provided potentials to a variety of construction applications. It is well appreciated that WSNs have advantages over traditional wired system, such as ease of installation and maintenance with increased cost savings and efficiencies. However, the obstruction of wireless signal from physical objects in the heterogeneous construction environment often brings challenges to WSN measurement system. This paper analyzed the obstruction characteristic of construction environment where construction materials, equipment, and built structures obstruct the wireless signal yielding negative effect of measurement system. By adopting evaluation criteria, such as packet reception rate, field experiments have been implemented to quantitatively identify the interference of wireless signal from penetration, reflection, and network traffic under the construction environment. The results show that reliable performance of wireless sensor in construction environment depends on the optimal separation distance between a receiver and a transmitter, obstruction types, obstruction thickness, and transmission interval. In addition, the methodology and experimental results of this paper could be used in the practical design of network topology when hundreds of sensor nodes form a mesh network in the large scale construction applications.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.379-380
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• 2023

The Post-Construction Evaluation and Management System has been operated over the past 20 years not only to analyze the performance of large-scale construction projects, and but also to provide useful reference data for future similar projects. Although the Post-Construction Evaluation and Management Center has been legally designated and operated since 2020, various problems have been occurring in the operation of the system. Accordingly, this study proposes strategies for facilitating Post-Construction Evaluation and Management System in terms of the following three aspects: (1) improving the implementation rate of post-construction evaluation; (2) improving the information management system related to post-construction evaluation; (3) improving the utilization of post-construction evaluation outcomes. Based on the results of this study, a specific action plan will be prepared, which is expected to contribute to the efficiency of construction project performance management in the future.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.11a
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• pp.117-120
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• 2005

The business market of architecture has got a system that controls a deposit according to the price function. This system is written on a law of contract about countries. So the main body of construction has to make a reasonable contract. This study is written about a rate of numerical index on controling a deposit. We tried to fine problems and solutions of labor expenses, instrument costs and material costs which is so big and changable on the construction market Labor expenses are expressed according to the rate of construction scale between direct and indirect cost that applies ability of works. Instrument costs are expressed according to an output method of a unit price annually and a weight allowance of local instrument conditions and use frequence. The last material costs expressed according to a local weight allowance make a decision of the material cost index. They applies locally relative index more than absolute one on what uses the price rate of producers and importations. This solutions are not enough to apply to the real market, so it needs to exam and to be on the market after a feasibility study.

• Journal of the Korea Institute of Building Construction
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• v.5 no.2 s.16
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• pp.161-166
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• 2005

This study is to evaluate on the increased cost of construction according to the depth change of concrete slabs in apartment building. When we increased the depth of concrete slab from 150mm to 180, 210mm, the qualitative and cost of construction were calculated by the high-rise type, the unit-size type. As a result of this study, in 32 Pyong type, increment of construction cost rate appeared by $5.1\%$ in case of increase from slab 150mm to 180mm, and $10.0\%$ in case of increase from slab 150mm to 210mm. In 45 Pyong type, Increment of construction cost rate appeared by $5.7\%$ in case of increase from slab 150mm to 180mm, and $10.2\%$ in case of increase from slab 150mm to 210mm. In 55 Pyong type, Increment of construction cost rate appeared by $2.4\%$ in case of increase from slab 150mm to 180mm, and $8.9\%$ in case of increase from slab 150mm to 210mm.

• Journal of the Korea Institute of Building Construction
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• v.21 no.2
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• pp.157-163
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• 2021

The accident rate is obtained by dividing the number of accidents by the number of regular workers. In the case off construction work, however, the accident rates are not accurately figured out, because they use the approximate number of regular workers, which is estimated based on the amount of construction work and the labor ratio. In addition, the current accident rate estimation method does not reflect the characteristics of construction types, such as building, civil, plant, etc. This study is conducted with the aim of presenting a supplementary method of accident rate assessment that incorporates the characteristics of type of construction. For the purpose of this, correlation and regression analysis are executed to verify the relationships between number of accidents and the amount of construction contract, and several equations are derived which shows the relationship between the number of accidents by accident types and amount of constract by construction types. The result shows that the non-residential work amount and the number of accidents showed a proportional relationship, while the civil work amount and the number of accidents showed an inversely proportional relationship. The results of this research are expected to calibrate the construction accident rates and to be used as an auxiliary indicator to determine the trend of annual accident rates by comparing the values with usual years.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.1124-1128
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• 2005

The duration of a construction project is not only a key element for taking a new order, but also a strict yardstick to determine certain project successful or not. However, since construction project is basically outdoor job and most of the activities are proceeded out-air, no matter how the schedule plan has been established accurately, actual project proceeds due to the weather condition, beyond anyone's control. In this paper, the functional relationship between work productivity rate and weather elements is suggested by regression analysis. Difference of the relationship and influence of weather due to the seasonal group are also revealed. With these results, by simulating actual weather data and generating weather forecast through historical data, more accurate schedule would be obtained.

• Korean Journal of Construction Engineering and Management
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• v.5 no.6 s.22
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• pp.203-211
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• 2004

This study is the results to survey on the problems and improvable Policies for current escalation system in construction contracts, through a Delphi survey to experts. From the survey results, it is desirable to decide the fluctuation rate of construction cost, which is the requirement of escalation clause, on the basis of inflation rate or construction cost index. The desirable price fluctuation rate is proposed as a $3\%$ level. However, it is difficult for construction companies to cope with the sudden increase of material price in advance, arising from short-term shock factors such as exchange rate and international raw material's price. Accordingly escalation system for specified materials, as an exceptional mode, should be introduced. As a method to calculate the fluctuation rate, ARCA(adjustment rate for the categories of articles) is more desirable than ARI(adjustment rate for an index), because the ARCA can be more reflected the characteristics of each construction work.To rationalize the ARI method, it is needed to announce the wage index, material index and machinery expense index via detailed classification by construction types. Also, it is desirable to prescribe the bidding date as a starting date of the price change, rather than contact signing date. considering the price change can happen since the biddiilg stage.

• Journal of Drive and Control
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• v.20 no.2
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• pp.7-14
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• 2023

Negative perceptions of the construction industry are prevalent due to the high accident rate at construction sites. Recently, with the gradual change of the perception in industrial safety, the demand for improving the safety level of construction sites has increased. Accordingly, the government is preparing various safety-level measures such as the Serious Disaster Punishment Act and support for industrial safety management costs. In addition, private industries are incorporating various safety equipment in the sites. This paper introduced the current status of safety sensors and solutions currently applied to construction equipment and industrial vehicles. The technology development direction suitable for construction equipment was introduced by comparing the operating environment of automobiles and construction equipment. and the need to develop performance standards to protect and revitalize the market for safety devices for construction equipment was suggested.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2022.10a
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• pp.169-170
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• 2022

As the size of construction projects has become larger in recent years, the nature of the disaster safety factors along with the progress of construction is also becoming more complex and diversified. Accordingly, the introduction of computerized construction, new technologies, and new construction methods has resulted in a variety of risk factors in the process and operations, and many new safety construction methods are being tried. Since the construction industry has variable working environments and constantly changes working methods and components depending on the rate of progress, workers at construction sites are always exposed to risk depending on the specific circumstances of the construction industry. This study attempts to collect and analyze major accident cases generated by major accident construction projects as a result of progress in construction work, and to derive the major causes and causes for each safety management activity that affect safety accidents.

• Korean Journal of Construction Engineering and Management
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• v.4 no.1 s.13
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• pp.122-130
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• 2003

Nowadays, as construction projects become bigger, the probability of construction accidents is higher than any other day. When construction accidents break out, we may suffer from the loss of life and property. For preventing these damages, there is lawed that some public constructions have to insure Contractor's all risks insurance policy (CAR), However, CAR is used to preventing the insured from the loss of construction accidents, it is debated that the premium rate of CAR is not fair to the insured (contractors) The objects of this thesis are as follows Firstly, the fairness of the premium rate of CAR is reviewed, and then the amount of risk of the insured evaluates and applies to the premium rate. Secondly, the development direction of components for evaluating the amount of risk of the insured is presented in the research. Lastly, how to use the team which assesses the risk of the insured and construction works is proposed for deciding reasonably the premium rate of CAR