| Summary: | 碩士 === 國立雲林科技大學 === 營建工程系碩士班 === 94 === In recent years, construction engineering has become larger and more complicated. Because of limited budget and time limitation, owners or stakeholders usually face risks in such complicated situations. For manage staffs in construction engineering, the knowledge and methods of risk management is very important. From the viewpoint of risk management, management staffs usually lower risks through contracts or other strategies, such as project delivery system which can transfer or redistribute risks to other principal parts of projects, because of the high degree of risks in construction cases and the complicated structure of risks. Therefore, for owners, it is essential to choose a suitable way to purchase to transfer or disperse risks.
In past, many researches which assist owners and mangement staffs to choose project delivery system has been developed. However, all of the former evaluation modes did not quantify the degree of risk transfer and dispersion. Some scholars suggest that it would save time and cost and improve quality to take risk transfer or dispersion into consideration before deciding the projects. Other scholars point out that the mode of procurement can transfer and disperse risks effectively with the figure of risk dispersion. It indicates that it becomes an important issue to see the way to procure as one of choices of strategies.
In practice, it is often disregarded that risks change with different strategies when choosing the mode of procurement. In other words, risks will change with the time and the space. The strategies to deal with risks affect risks most. Sometimes they even change risks from intrinsic quality of risks or causal relationship. Therefore, the beneficial result of the procurement manner relates to the success or failure of entire risk management, even relates to the success or failure of the project management.
Actually, in the past, construction industry lacked historical data of the occurrences of risk factors, i.e. risk project, probability and impact etc., in different procurement ways. This phenomenon caused that risks could not been evaluated effectively. Therefore, in most cases, it is hard for experts to offer the clear and definite probability directly. Most of them show the possibility of occurrence of risks in words. This causes the deficiency of many analysis methods. So, with the use of fuzzy theory, we can solve the fuzziness and vagueness of risks by utilizing linguistic variables fitting human thinking mode more and get the probability of occurrences of events objectively from the probability which experts can not describe precisely and represent with linguistic variables in authentic situations. In this way, we can get the solution for those unclear and indefinite problems and can make up the deficiency in the traditional decision-making theories.
At owner’s position and viewpoint of risk dispersion, it is crucial to choose a suitable procurement mode. In order to do this kind of decision, it needs to consider risk factors in different dimensions and need to define and identify risks. This study tried to identify the risk factors which affect the quality of projects through literature review and classified the risk factors into 11 main groups, 64 subgroups, and 106 items to be the basis of evaluation analysis in different modes of procurement in later part. Besides, in order to get the occurrence probability and impact of each risk factor, the researcher invited experts to fill the questionnaire to get the relatively important risk factors in each mode of procurement. The analysis of questionnaires was done by using the fuzzy theory. The researcher calculated the probability and impact of each factor and other relative information and analyzed the sensitive degree with α-cut and the fuzzy ordering. The researcher selected α= 0∼1 and β=0∼1 to do simulations in 121 different situations. The simulations were to observe the changes of orders of influence degree in projects which were caused by risk factors under different decision-making environments and different pessimistic degrees (different α value and different β value). By utilizing analysis of fuzzy statistics, the most appropriate order of risk factors could be got. Through the methods mentioned above to analyzing different modes of procurement, the order of risk factors affecting projects more at different stages in different modes of procurement can be obtained.
The result can offer owners the basis for identifying risks and be the base of risk evaluation and risk analysis in the future. It can also help management staffs to frame better management strategies in advance, lower the impact to projects cause by risks, improve the uncertainty of projects, raise the authenticity of cases, and provide owners or management staff suitable strategies. In other words, it is to choose appropriate strategies to achieve the goal of risk management and to put the benefit of risk management into effect.
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