I. Introduction
The cost of software projects and the quality of products are affected by the correctness of software effort estimation. Accurate cost estimation of a software development effort is critical for good management decision making. Predicting software development effort with high precision is still a great challenge for project supervisors. On the otherhand, accurate estimation of the effort and cost of a software system is one of the vital and challenging tasks for software project management. It aids in agreement negotiations, project planning and effective distribution of resources. However, estimates at the introductory stages of the project are the most difficult to acquire because the primary source to estimate the cost comes from the requirement specification documents[1]–[3].