Research On The Determining Of The Provisional Sum Based Upon Case-based Reasoning

Provisional sum is the bidder's reserved fund of risk,which its final goal of setting is letting the final account at completion approaching to the contract sum so as to realize efficient investment control of construction project,not only to deal with the occurrence of unexpected events caused by the capital chain break,but also to achieve the effective use of the bidder's funds.However,owing to lacking of the importance of knowledge of provisional sum,the phenomenon that bidders often set it randomly occur frequently and the regulations of the range of provisional sum are vague so that it is hard to implement.It can be seen that there is no scientific method to determine provisional sum in theory and practice.In view of the limitations of the traditional method,this paper introduces case-based reasoning technology as the method of determining the amount of the provisional sum to determine it scientificly and reasonably.Firstly,for the research about case representation of the determination of the amount of provisional sum,the solution is,through the information precipitation method,to extract the index elements from two levels.First of all,extract the elements from the provisions of the national and regional normative documents.Through the feasibility analysis,use expert interview method to select the feasibility factor set which is time feasible,technically feasible and function feasible as the final influence factor set,and use AHP to determine weight of each factor.Based on the set of influencing factors,which is a case representation in the case representation,combine the case description and case description of the case to form the whole case database.The data base of this research is 67 actual cases of government investment projects,which builds a project case database?Secondly,for the case retrieval and adjustment research of the determine of the amount of provisional sum,the solution path is a hybrid search strategy.First,generalize and retrieve the case database,and screen the cases of professional and structural types,which are the same as the target cases,are as a potential case base.Then,through the quantification of the impact index,estimate the similarity between the target case and the source case of the case database by the nearest neighbor retrieval method,use Euclidean distance for specific calculation.By setting the similarity threshold,obtaine a sufficient similarity case or minimal similarity case of the target case.If there is no similar case,but there is a minimum similar case,need to adjust the case of the smallest similar cases,a single case adjustment in accordance with the weight of the index to adjust,multi-case adjustment in accordance with the similarity of each case weighted average derived adjustment solution.And use the case-based reasoning technique to determine the provisional sum accurately.In this paper,we will match the case-based reasoning technology with the investment control problem in the field of project management,and make the research on the rationality and scientificity of the provisional sum to provide the basis for the risk control of engineering practice personnel.