Using LP/IP Hybrid method for time-cost tradeoff
a. Suggested method
Obtaining a good and nearly optimal solution with a reasonable amount of computational effort is the major motivating factor for this method. Integer programming can find the exact optimal solution, but it is computationally intensive.
The LP/IP hybrid method is a hybrid approach uses:
(1) Linear programming to create a lower bound of the lowest direct cost curve efficiently; and (2) Integer programming to find the exact solutions.
Following describe the formulation of linear and integer programming models. Examples are given to demonstrate how to formulate the mathematical models. Linear programming algorithms, such as simplex method, can then be used to find the optimal solutions. Much commercially available linear programming software, such as Lindo, can perform the task very efficiently. The formulation of the objective function and constraints for linear programming, however, is time-consuming and prone to error. From the writers ' experience, formulating the objective function and constraints rarely succeeds without several revisions. For large CPM networks, the effort to check and verify the formulation could be phenomenal. The convex hull method in conjunction with linear programming establishes the lower bounds for time-cost relationships of a project. These lower bounds give construction planners a general idea of the project time-cost relationship. From these lower bounds, construction
Cost management planning happens early on in the project planning phase and should be refined throughout the project’s life cycle as additional details become available. The project’s cost management plan sets the framework for all of the project’s cost management processes. The accuracy of estimating a project’s cost is essential to the successful or failure of the project. This makes choosing the right estimating techniques crucial for a project.
Along with the Benefit Measurement Method, Constrained optimization method can also be used which involves mathematical approach. Since this method involves the mathematical approach, several calculations are performed in order to take a decision to accept or reject the project. “Mathematical models, also known as Constrained Optimization Methods, are a category of project selection methods, which is a tool and technique of the Develop Project Charter process” (PMP, 2008). Cost-benefit analysis is one of the methods which fall into this category. All the positives and negatives of the project are taken into consideration and then the negatives are carefully excluded from the benefits. Different results are produced for the different projects. The most worthy and financially rewarding option are selected from these results. When employing this method, there are many things that are to be considered such as the impact of the decision on the development of the organization in the future, the length of time the equipment lasts and whether it is possible to do the cost control during the project.
The cost, team size and LOC are measured on the bases of COCOMO model. It is a constructive cost mode. Effort of the project is calculated by the help of algorithm models. One of these models which are widely used is COCOMO model. For the cost estimation of any project, COCOMO (constructive cost model) is used. This model was developed by Boehm in 1981. There are three versions of the COCOMO which are listed below:
As discussed in chapters one and chapter two of this paper, the cost involved for implementing a
The cost planning is one of important phases for project management. It will goes through whole project’s life cycle. It is foundation of project and it will tell the project are measured, reported and controlled in every process. Estimating is the process of forecasting or approximating the time and cost of completing project deliverables.
The paper discuss the need and justification of the PMP for this construction project, areas that are
The paper discuss the need and justification of the PMP for this construction project, areas that
The mathematical model created to schedule all the projects is based upon a number of
all of the cases the algorithms were able to find the cheapest path between the
Optimization Once the decision problem is fully described in a model, criteria for decision making stipulated and constraints identified, the decision-maker can select the best possible solution.
Planning an Incremental-build project involves planning for analysis and design plus planning the number of and frequency of
Develop the project plan in line with the project parameters by identify and access appropriate project-management tools like critical path method, gantt and bar chart, life cycle cost analysis and so on.
Exact optimisation method is the optimisation method that can guarantee to find all optimal solutions. In principle, the optimality of generated solution can be proofed mathematically. Therefore, exact optimisation is also termed as mathematical optimisation. However, exact optimisation approach is impractical usually. The effort of solving an optimisation problem by exact optimisation grows polynomially with the problem size. For example, to solve a problem by brute force approach, the execution time increases exponentially respect to the dimensions of the problem.
Complex building projects require the use of a more sophisticated type of schedule called the critical path method or CPM shown in Figure 13. This type of schedule indicates the dependencies and interrelationships between different activities. Those activities are shown as a network. A CPM schedule shows the sequence of each activity, the start of each activity, the dependence of that activity on the completion of a preceding activity, and how the completion of that activity will restrict the commencement of subsequent activities.
The construction industry is one of the most unstable platforms. The main factor which gives this instability is the cost and time planning. By seeing the examples of real life cost and the time are the main factors that lead to delaying or incompletion of the project. This causes lots of problem to the client and also degrades the value of the company.