• Clean Technology
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• v.25 no.2
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• pp.147-152
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• 2019

Electrostatic precipitator that shows a good performance for the removal of particulate matter is important for controlling emissions from industrial facilities and power plants. The efficiency of the electrostatic precipitator on the removal of particulate matter is highly affected by the flow pattern inside the electrostatic precipitator. A number of studies have been conducted to obtain uniform flow distribution inside electrostatic precipitators. An electrostatic precipitator (ESP) with a length of 3.5 m and a height of 0.875 m was designed and installed in this study. The ESP included an inlet duct, diffuser, body, and contractor. Three perforated plates were installed in the diffuser of the ESP. Five pitot tubes were installed vertically and used to measure flow distribution in the cross section of the ESP body. Root mean square deviation value (RMS%) was used to examine the flow distribution inside the ESP when the perforated plates were installed in the diffuser. Flow distribution was also investigated in relation to the porosity of the perforated plate. The results showed that the perforated plates improved greatly the flow distribution inside the electrostatic precipitator. In addition, the most uniform flow distribution was found with 40%, 50%, and 50% porous perforated plates located from the inlet of the diffuser.

• Journal of Construction Engineering and Project Management
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• v.8 no.4
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• pp.1-24
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• 2018

In the last decade, the use of Building Information Modeling (BIM) as a new technology has been applied with traditional Computer-aided design implementations in an increasing number of architecture, engineering, and construction projects and applications. Its employment alongside construction management, can be a valuable tool in helping move these activities and projects forward in a more efficient and time-effective manner. The traditional stakeholders, i.e., Owner, A/E and the Contractor are involved in this BIM system that is used in almost every activity of construction projects, such as design, cost estimate and scheduling. This article extracts major features of the application of BIM from perspective of participating BIM components, along with the different phrases, and applies to them a logistic analysis using a fuzzy performance tree, quantifying these phrases to judge the effectiveness of the BIM techniques employed. That is to say, these fuzzy performance trees with fuzzy logic concepts can properly translate the linguistic rating into numeric expressions, and are thus employed in evaluating the influence of BIM applications as a mathematical process. The rotational fuzzy models are used to represent the membership functions of the performance values and their corresponding weights. Illustrations of the use of this fuzzy BIM performance tree are presented in the study for the uninitiated users. The results of these processes are an evaluation of BIM project performance as highly positive. The quantification of the performance ratings for the individual factors is a significant contributor to this assessment, capable of parsing vernacular language into numerical data for a more accurate and precise use in performance analysis. It is hoped that fuzzy performance trees and fuzzy set analysis can be used as a tool for the quality and risk analysis for other construction techniques in the future. Baldwin's rotational models are used to represent the membership functions of the fuzzy sets. Three scenarios are presented using fuzzy MEAN, AND and OR gates from the lowest to intermediate levels of the tree, and fuzzy SUM gate to relate the intermediate level to the top component of the tree, i.e., BIM application final performance. The use of fuzzy MEAN for lower levels and fuzzy SUM gates to reach the top level suggests the most realistic and accurate results. The methodology (fuzzy performance tree) described in this paper is appropriate to implement in today's construction industry when limited objective data is presented and it is heavily relied on experts' subjective judgment.

• Journal of the Society of Disaster Information
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• v.15 no.3
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• pp.409-417
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• 2019

Purpose: Since the implementation of the Chemical Substance Management Act, data on the number of occurrences by annual chemical accident in Korea and the contractor's contract data received from the competent authority were used. After the implementation of the contract reporting system, the contribution to the reduction of chemical accidents is summarized by statistical data. The characteristics of each region, month, type and those of similar industries and human life were compared and analyzed. Method: 4 years of chemical accident statistics from 2015 to 2018 and since 2003, we have used data from the Chemical Safety Clearing-House (CSC), which provides safety information on cases of chemical accidents. Results and Conclusion: The risk of accidents increases as a number of unskilled workers are put into the workplace during the period when the hazardous chemical handling process is temporarily suspended. Through the reporting for awarding a contract, the operators are strengthening the safety management of chemical accidents by educating unskilled workers and wearing personal protective equipment.

• Korean Journal of Construction Engineering and Management
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• v.20 no.3
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• pp.22-30
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• 2019

The purpose of this study is to derive basic data of the Guaranteed Maximum Price(GMP) process and to present specimens that can be used at the time of execution of CM at Risk project in South Korea. CM at Risk project is issued in South Korea, but the actual data is lack. On the other hand, CM at Risk project is universalized and the market of the CM at Risk is steadily growing. Because of that, in this study, The United States cases was selected as a sample. GMP consists of CM's fee, CM contingency, project direct cost, project indirect cost, allowance. GMP negotiations are performed before the end of design completion, and after 3 rounds of estimation comparison, preliminary GMP is confirmed. GMP can be multiple contract and it is useful for Procurement of long lead materials and early construction. If the actual cost is lower than expected GMP, sharing of the saving is an option since the conflict of interests between the client and the contractor can occur.

• Korean Journal of Construction Engineering and Management
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• v.22 no.2
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• pp.72-79
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• 2021

This study intends to explore the factors influencing the progress of housing construction projects by regional housing associations. In order to develop the importance weight of factors classified into 11 factors with 4 categories, AHP and Fuzzy methodologies are implemented based on survey analysis by field experts and project participants. Research findings indicate that the four categories of land, business, legal entity, and copartner, and the factors of professionalism, location, transparency, purchasing cost, administrative supervision, landlord participation, liability for damages, etc are in order of importance. It is noteworthy that the contractor, financial institution, developer, legal expert, and association consider professionalism, location, purchasing cost, and transparency as the most important factors respectively. This study aims to help provide the implication for factors Influencing the progress of housing construction project to project participants.

• The Journal of the Korea Contents Association
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• v.21 no.3
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• pp.626-633
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• 2021

In the event of a housing sale guarantee accident, the Housing and Urban Guarantee Corporation shall be responsible for the guarantee by refunding the moving-in money unless there are special circumstances to the contractor. The Housing and Urban Guarantee Corporation may refuse to perform the refund based on the Terms and Conditions Regulations Act, but disputes continue to arise between interested parties in this regard. Therefore, the purpose of this study is to study the problems and improvement measures for legal issues related to the implementation of the refund. First, the issue of guarantee effectiveness and scope of guarantee under the Terms and Conditions Regulation Act. Second, the problem of guarantee contract for conditional third parties of Housing and Urban Guarantee Corporation. Third, the problem of the attitude of the existing precedents of the Supreme Court was examined. As a result of reviewing these legal issues, it was confirmed that the interpretation of terms and conditions according to the implementation of the refund is being interpreted in accordance with the principle of good faith, but according to individual cases, precedents can be divided into positive and negative judgments. In addition, despite the fact that the housing pre-sale guarantee is a guarantee contract for a conditional third party, it was confirmed that the buyer suffered damages in good faith through active disputes with the interested parties. Accordingly, the Housing and Urban Guarantee Corporation proposed an improvement plan for roles and cooperation items to meet the purpose of establishment for the stability of the customer's housing.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.765-778
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• 2021

The purpose of this study is to prevent fire accidents in advance by deriving prior knowledge among groups about temporary fire-fighting facilities of workers at construction sites and devising appropriate improvement measures. The findings are as follows.First, in the case of fire extinguishers, statistical attention was paid to the contractor, supervisor, partner worker and fire extinguisher manager between designations. 87% of fire managers and 70% of facility supervisors said fire extinguisher management managers needed to be designated for each type of construction, which requires designation of fire extinguisher management managers, frequently checking and relocating. Second, in the case of simple fire extinguishing facilities, statistical attention was paid to the application of penalties for unauthorized use of fire extinguishing facilities with construction companies, supervisors, and business partners.Third, in the case of emergency alarm measures, statistical attention was paid to the application of emergency alarm sound to temporary broadcasting facilities with construction works, supervisors, and business partners.Fourth, in the case of induction, statistical attention was paid to the application of connection between construction works, supervisors, and partner workers, such as passage guidance, emergency lighting, etc.It was found that 65% of construction workers and 55% of electrical workers had different applications such as aisle guidance and emergency lighting for each type of business partner. In order to resolve blind spots such as evacuation zone guidance due to the structure of the building, it is necessary to easily distinguish the direction of the entrance door from a long distance by applying it in conjunction with passage guidance lights and emergency lighting.

• Journal of the Society of Disaster Information
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• v.17 no.2
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• pp.306-318
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• 2021

The dispatch law has a negative impact on safety management at construction sites as the command and command relationship to safety assistants of the original contractor are applied to the dispatch law. Purpose: The purpose is to study the importance and impact of safety management according to the dispatch law, and to propose a direction for safety management so that safety assistants can actively and proactively prevent accidents. In this study, we used AHP analysis techniques for experts to achieve the final goal and verified the suitability through logistic regression. Method: AHP analysis technique is used for experts and workers and logistic regression analysis is conducted. Result: The result of analyzing scenario data where the dispatch method can be applied showed the importance in the order of education (SkillUp education), management (work-time management) and direct instructions (feedback instruction). In logistic regression analysis, feedback is the factor that affects direct instruction, and in education management, the ratio of education management is 3.42 times lower than that of other groups when only the team leader of the company gives work instructions. Conclusion: The management of feedback and education is more important than anything else within the range in which the dispatch method is not applied, and the expansion of non-face-to-face online education is judged to avoid the violation of dispatch method because the expansion of non-face-to-face online education due to covid 19 recently has brought more various target for safety education.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.3
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• pp.439-448
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• 2022

Recently, domestic small and medium-sized subcontractors participating in the overseas construction market are suffering from the continuous loss and damage due to the insufficient recognition of the importance of risk Sub-Clauses among conditions of subcontracts. Therefore, the need to derive risk Sub-Clauses for conditions of the subcontract has been raised, but until now, previous studies have been conducted focusing on deriving risk Sub-Clauses for standard conditions of contract for construction between the Employer and the Contractor. In this study, 52 risk Sub-Clauses were derived on the basis of the influence size of the Sub-Clauses through the Delphi technique targeting 94 Sub-Clauses of conditions of standard subcontract for construction edition 2011, issued by the International Federation of Consulting Engineers (FIDIC) and In addition, 33 key risk Sub-Clauses were finally derived through the PI Risk Matrix by Probability and Impact. The results of this study provide will useful information on key risk Sub-Clauses that need to be reviewed in advance to minimize contractual risks at the stage of bidding and signing contracts for overseas subcontract construction projects.

• Journal of the Society of Disaster Information
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• v.19 no.1
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• pp.18-30
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• 2023

Purpose: This study is to contribute to the development of monitoring technology through the increase of confidence in construction monitoring by deriving the analysis of construction monitoring cost and improvement measures of railway tunnel construction in Seoul. Method: It presents the status on design and contract of construction monitoring cost, status on application construction monitoring cost and its analysis, analysis on safety management cost and quality management cost, expansion of application of the price calculation standard for monitoring management services to improve this, and monitoring for direct order of ordering organization. Results: If the monitoring management service that was meanwhile ordered as included in the construction work is performed by the directly selected company of ordering organization through the preliminary screening for bidding qualification, then the improvement of monitoring quality and the accurate monitoring data can be secured. Conclusion: For the price calculation standard for monitoring management service, the application of actual cost addition method under the Engineering Promotion Act and the calculation standard of monitoring management cost for standard estimation for ground survey should be extended through the direct order of ordering organization, not the method to be included in the net construction cost where it is performed by a subcontractor via contractor.