• Journal of the Korean Operations Research and Management Science Society
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• v.24 no.2
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• pp.41-51
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• 1999

In sole-source procurement contraction for government goods and services, the buyer (government) needs to derive the optimal actions from the contractor so the buyer can obtain the maximum utility and the contractor, or single-source supplier, is guaranteed the equivalent of a minimum level of profit. Under the assumption of risk-neutrality for both the buyer and the contractor and the buyer's unobservability of the contractor's action, it is necessary for the buyer to design a (mathematical) model to achieve the above objective. This paper considers the mathematical formulation in which two problems - moral hazard and adverse selection - are present simultaneously; furthermore, from the formulation, a GAMS (General Algebraic Modeling System) program is used for a possible buyer to obtain the optimal actions.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.758-763
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• 2009

In Japan, it has been argued between architects and contractors that which process is desirable, the traditional process or the design-build process. It is called the contractor-designer issue. In 1968, Kajima Corporation chairman Morinosuke Kajima and the Japan Architects Association had a public controversy over it. On the other hand, in practice, architects and contractors have secured quality of buildings thorough a close communication in the design and construction process of building. What are the relationships between architects and contractors? What roles do architects and contractors have in practice? This study has two aims. First one is to analyze the contractor-designer issue based on roles and relationships between architects and contractors, and then to show conflicts between them. Second one is to consider issues which architects face in the relationships with contractors.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1474-1478
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• 2009

The cooperation and trust among the project participants play a critical role in the success or failure of any delivery system in construction industry. But it is very difficult to establish trust between an owner and a contractor when rational people only pursue only their own material self-interest. Based on the principal-agent theory, this paper will introduce the altruistic behavior into the traditional principal-agent model, and model the reciprocal behavior between the owner and contractor. We will show that both the owner and the contractor benefit from their reciprocal behavior, and hence trust establishing between them is possible. More importantly, we will proof that the higher the project uncertainty is, the more important trust establishing is.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.155-156
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• 2021

Most of the construction works in domestic are not direct undertaking work, but by a contract method including subcontracting. Therefore, a general contractor for each project jointly carry out construction work with a specialty contractor for each engineering type. However, in terms of contract, this method is not a joint venture contract, but a subcontract. Accordingly, this system can cause various problems between the prime contractor and the subcontractor. Therefore, this study aims to extract and present the actual obstacle factors in terms of specialty contract company performing specialty construction work for construction project. The presented contents are expected to present the standard for the cooperation system that the prime contractor and the subcontractor can win-win.

• Journal of Construction Engineering and Project Management
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• v.6 no.3
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• pp.1-7
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• 2016

The purpose of this paper is to develop a model for selecting the best contractor in the Gaza Strip using the Artificial Neural Network (ANN). The contractor's selection methods and criteria were identified using a field survey. Fifty four engineers were asked to fill a questionnaire that covers factors related to the selection criteria of contractors practiced in Gaza Strip. The results shows that the dominant part of respondents (91%) confirmed that the current awarding method "the lowest bid price" is considered one of the major problems of the construction sector, "award the bid to the highest weight after combination of the technical and financial scores" represented 50% of the respondents. The criteria weights were determined based on Relative Importance Index (RII. Ninety-one tenders(13 projects) were used to train and test the ANN model after re-evaluating the contractors depend on the weights of factors to select the best contractor who achieves the highest score. Neurosolution software was used to train the models. The results of the trained models indicated that neural network reasonably succeeded in selection the best contractor with 95.96% accuracy. The performed sensitivity analysis showed that the profitability and capital of company are the most influential parameters in selection contractors. This model gives chance to the owner to be more accurate in selecting the most appropriate contractor.

• Journal of KIBIM
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• v.8 no.1
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• pp.43-55
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• 2018

Recently, there have been increasing studies on the application of digital technology, which has its focus of the irregular building. However, most of these studies have not clarified the objective of the technology and the effectiveness of professional manpower on its performance. This study analyzes actual used technology and the role of specialty contractor. It presents a framework to quantify the performance of the specialty contractor. For these purposes, this paper presents a proposed method to evaluate the activities of specialty contractors using a queueing model. As an attempt to verify the model, an actual irregular building project, in which digital fabrication is applied, is investigated during the construction phase. In order to collect the digital fabrication data, digital fabrication reports and specialty contractor's work log of project are reviewed. In addition, Digital Fabrication input personnel, productivity data are collected through interviews with experts involving in the case project. Analysis of specialty contractor's performance in digital fabrication reveals that the wait status of project participants varies probabilistically depending on the digital technology application level. The results of this study are expected to contribute toward the improvement of the production level in the construction industry.

• Journal of the Korean Institute of Gas
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• v.18 no.2
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• pp.21-27
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• 2014

A MILD(Moderate and Intense Low oxygen Dilution) combustion, which is effective in the reduction of NOx, is considerably affected by the recirculation flow rate of hot exhaust gas to the combustion furnace. The present study used a coanda nozzle for the exhaust gas recirculation in a MILD combustor. A numerical analysis was accomplished to elucidate the effect of exhaust gas entrainment toward the furnace with or without a coaxial contractor. The result of the present CFD analysis showed that the entrainment mass flow rate without a coaxial contractor had 18% larger than that with a coaxial contractor when the mixed gas outlet pressure was ambient pressure. On the other hand, if the outlet pressure increased, the mass flow rate with a contractor was larger than that without a contractor. It could be analysed by the entrainment driving force composed with the nozzle throat pressure, inlet and outlet pressures and flow cross sectional area.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.6
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• pp.850-861
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• 2013

This study aimed at investigating any differences perceived between the contractor and the contractee based on an importance-performance analysis (IPA) of foodservice quality attributes. Questionnaires were distributed to 200 personnel concerned in the Busan, Ulsan and Kyungnam areas and a total of 134 valid responses were used for analysis. Of the 23 foodservice quality attributes, the factors of 'food quality', 'employee service', 'hygiene and safety', 'customer orientation' and 'operation quality' were induced from a scale purification process through the exploratory factor analysis. The level of importance (p<0.01) of the 'hygiene and safety' factor and 'employee service' factor was not found to be significantly different between the groups. In the level of performance, the factors of 'food service', 'employee service', 'customer orientation' and 'operation quality' were found to be perceived significantly lower than expected by the contractor group. In the importance level, 'food quality', 'employee service', 'hygiene and safety', 'customer orientation' and 'operation quality' were rated by the contractor as 4.03, 4.30, 4.27, 4.01 and 4.12 points, respectively. In contrast, in the performance level, perceived 'food quality', 'employee service', 'hygiene and safety', 'customer orientation' and 'operation quality' were evaluated as 3.57, 3.94, 4.06, 3.83 and 3.95 points, respectively.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.05a
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• pp.119-124
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• 2006

Design-Build, one contractor is responsible for both the design and construction, has become more popular since the government framed the policy on how to activate the design-build projects in 1996. The reality is, however, there are many problems encounted on Contractor Selection Method for Public Design-Build Projects. The purpose of this paper is to improve the problems, no way to meet the goal(value) the owners expect from the design-build projects, for instance, not fully reflecting the characteristics of projects and owners intention, not systematical enough to judge if bidders could carry out the contract. This study will insist we introduce Best Value Procurement, which is being commonly used in some advanced countries recently, so that we would properly select the contractor suitable for Best Value concept which totally depends on the owners, types of work and specified conditions. Furthermore, by passing through the Two-Step Procedures following Pre-qualification in Best Value Procurement, we expect it lighten the bidders' burden for proposal and the owners' complicate bid administration.

• Journal of Construction Engineering and Project Management
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• v.10 no.1
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• pp.1-15
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• 2020

With the increased dependence on subcontracting in the construction industry, the operational relationship between main contractors and subcontractor plays an imperative role in successful project delivery. Consequently, improving this relationship increases the probability of project success and enhancing project performance. A wide range of research has confirmed that partnering improves the main contractor-subcontractor relationship. Though the positive impact of partnering on project performance is supported by a plethora of evidence, the guiding theory on practical partnering process steps is limited. The study aimed at improving subcontracting in the construction industry through a partnering process relevant to Zambia guided by factors obtained from industry expects. Questionnaire surveys and Semi-structured interview were adopted to investigate the perception of construction industry professionals and academics towards the main contractor-subcontractor relationship along with improvement factors. The findings showed that the relationship between main contractors and subcontractors on most projects in Zambia is unsatisfactory therefore justifying attention. Top factors that can enhance the main contractor-subcontractor relationship were identified. From the factors deduced and guidelines on partnering best practices, a project partnering model was developed.