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### SOFTWARE ESTIMATION COCOMO AND FP CALCULATION

• 1. U & P U. Patel Department of Computer Engineering SOFTWARE ENGINEERING COCOMO-FP calculation Prepared by: Dr. Sneha Padhiar Assistant Professor, U & P U. Patel Department of Computer Engineering 1 4/10/2024
• 2. 2 Software Cost Estimation • Determine size of the product • From the size estimate, • determine the effort needed. • From the effort estimate, • determine project duration, and cost.
• 4. 4 Software Measurement  Direct Measures (internal attributes) Cost, effort, LOC, speed, memory  Indirect Measures (external attributes) Functionality, quality, complexity, efficiency, reliability, maintainability
• 5. 5 Size Oriented metrics  Size-oriented software metrics are derived by normalizing quality and/or productivity measures by considering the size of the software that has been produced. simple size-oriented metrics for each project:  Errors per KLOC (thousand lines of code)  Defects per KLOC  \$ per KLOC  Pages of documentation per KLOC  Errors per person-month  KLOC per person-month  \$ per page of documentation
• 6. 6 Software Cost Estimation Techniques • Empirical techniques: • an educated guess based on past experience. • Heuristic techniques: • assume that the characteristics to be estimated can be expressed in terms of some mathematical expression. • Analytical techniques: • derive the required results starting from certain simple assumptions.
• 7. 7 Empirical Size Estimation Techniques •Expert Judgement: •An euphemism for guess made by an expert. •Suffers from individual bias. •Delphi Estimation: •overcomes some of the problems of expert judgement.
• 8. 8 Software Size Metrics •LOC (Lines of Code): •Simplest and most widely used metric. •Comments and blank lines should not be counted.
• 9. 9 COCOMO Model •COCOMO (COnstructive COst MOdel) proposed by Boehm. •Divides software product developments into 3 categories: • Organic • Semidetached • Embedded
• 10. 10 Elaboration of Product classes • Organic: • Relatively small groups • working to develop well-understood applications. • Semidetached: • Project team consists of a mixture of experienced and inexperienced staff. • Embedded: • The software is strongly coupled to complex hardware, or real-time systems.
• 11. 11 COCOMO Model(CONT.) • For each of the three product categories: • From size estimation (in KLOC), Boehm provides equations to predict: • project duration in months • effort in programmer-months • Boehm obtained these equations: • examined historical data collected from a large number of actual projects.
• 12. 12 COCOMO Model(CONT.) •Software cost estimation is done through three stages: •Basic COCOMO, •Intermediate COCOMO, •Complete COCOMO.
• 13. 13 Basic COCOMO Model(CONT.) •Gives only an approximate estimation: • Effort = a1 * (KLOC)^a2 • Tdev = b1 * (Effort)^b2 • KLOC is the estimated kilo lines of source code, • a1,a2,b1,b2 are constants for different categories of software products, • Tdev is the estimated time to develop the software in months, • Effort estimation is obtained in terms of person months (PMs).
• 14. 14 Development Effort Estimation •Organic : • Effort = 2.4 (KLOC)^1.05 PM • Semi-detached: •Effort = 3.0(KLOC)^1.12 PM • Embedded: •Effort = 3.6 (KLOC)^1.20PM
• 15. 15 Development Time Estimation •Organic: •Tdev = 2.5 (Effort)^0.38 Months •Semi-detached: •Tdev = 2.5 (Effort)^0.35 Months •Embedded: •Tdev = 2.5 (Effort)^0.32 Months
• 16. 16 Development Effort & Time Estimation • Organic : • Effort = 2.4 (KLOC)^1.05 PM • Tdev = 2.5 (Effort)^0.38 Months • Semi-detached: • Effort = 3.0(KLOC)^1.12 PM • Tdev = 2.5 (Effort)^0.35 Months • Embedded: • Effort = 3.6 (KLOC)^1.20PM • Tdev = 2.5 (Effort)^0.32 Months
• 17. 17 Example • The size of an organic software product has been estimated to be 32,000 lines of source code. • Effort = 2.4*(32)^1.05 = 91 PM • Nominal development time = 2.5*(91)^0.38 = 14 months
• 18. Let’s Try • Assume that the size of an organic s/w product has been estimated to be 32,000 lines of source code. Assume that the average salary of software be Rs. 15,000/- month. Determine the effort required to develop the software product and the nominal development time. • Suppose you are developing a software product in the Embedded mode. You have estimated size of the product to be about 1, 00,000 lines of code. Compute the nominal effort and development time.
• 19. 19 Function Point Metric • Overcomes some of the shortcomings of the LOC metric • Proposed by Albrecht in early 80's: • FP=4 #inputs + 5 #Outputs + 4 #inquiries + 10 #files + 10 #interfaces • Input: • A set of related inputs is counted as one input.
• 20. 20 Function Point Metric • Output: • A set of related outputs is counted as one output. • Inquiries: • Each user query type is counted. • Files: • Files are logically related data and thus can be data structures or physical files. • Interface: • Data transfer to other systems.
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• 29. Practice sum FP: Compute function point value for a project with the following domain characteristics: No. of I/P = 30 No. of O/P = 62 No. of user Inquiries = 24 No. of files = 8 No. of external interfaces = 2 Assume that all the complexity adjustment values are average. Find FP Point and LOC for the same. Using COCOMO model calculate the total effort required to complete above task COCOMO: Suppose you are developing a software product in the organic mode. You have estimated size of the product to be about 1, 00,000 lines of code. Compute the nominal effort and development time.
• 30. Calculator Link • https://w3.cs.jmu.edu/bernstdh/web/common/webapps/oop/fpcalculat or/FunctionPointCalculator.html • http://groups.umd.umich.edu/cis/course.des/cis525/js/f00/harvey/FP _Calc.html • https://www.qsm.com/resources/function-point-languages-table
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