Optimal Scheduling in Construction Projects under Uncertainty using Universal Generating Functions

نوع: Type: thesis

مقطع: Segment: masters

عنوان: Title: Optimal Scheduling in Construction Projects under Uncertainty using Universal Generating Functions

ارائه دهنده: Provider: Mohammad Hosien Roshani Neshat

اساتید راهنما: Supervisors: Mohsen Babaei

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: Jalal Akbari-Seyed Mahdi Hosiennian

زمان و تاریخ ارائه: Time and date of presentation: 2023/3/7

مکان ارائه: Place of presentation: class 5a

چکیده: Abstract: In construction projects, many factors can cause uncertainty, among these factors are: special weather conditions or seasonal changes, unexpected natural events, shortcomings in the design, lack of timely delivery of materials, management interference in project sub-sectors , new complexities of the project, incomplete information and unforeseen conditions for the site. Therefore, a construction project is a set of activities that have uncertainties in their time or cost. These uncertainties can cause large variations in the completion time or total cost of the project. One of the important goals in real projects is to minimize the project completion time. Of course, it should be noted that in order to fulfill this goal, the limitation of resources (both materials and manpower) should be considered in the form of project costs. On the other hand, the resource limitation can be considered as a budget limitation and the scheduling problem can be modeled with the aim of reducing the cost with a time limit to complete the project. Accordingly, the interaction of time and cost has been considered by many researchers. In the conditions of uncertainty, time and cost indicators are replaced by reliability indicators of project completion time and project completion cost risk, and therefore, decisions should be made based on these two indicators.This research is looking for a method to determine the activities that affect the project completion time and prioritize them, so as to increase the reliability of the project completion time to the maximum possible amount, taking into account the limited resources. For this purpose, compromise functions between time and cost are used in each activity and thus the optimal cost in each activity is also determined. In addition, in this research, the method of general probability generating functions is used to determine the reliability of the project completion time. This method is a faster method compared to the simulation methods, while it is possible to apply it to all kinds of probabilistic functions. The proposed method has the ability to simultaneously optimize the cost and time of the project under uncertainty. Also, the proposed method is highly accurate in performing calculations and can be used for any type of distribution because it uses the developed NRB method to determine the fitting function, whose accuracy and speed have been proven in solving networks with uncertainty and limited Not to any distribution. By increasing the number of repetitions and also increasing the number of activities of the project scheduling network, the calculation time increases and the solution is reached later

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