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COCOMO (Software Engineering)
- 1. COCOMO Presented By - BiswadeepMukhopadhyay biswadeep.mukhopadhyay00@gmail.com B.Sc. Computer Science (Honours) University of Burdwan
- 2. Serial No. ContentSlide No. 1 Overview of COCOMO 3 2 Stages of COCOMO 4 3 Basic COCOMO 5 - 6 4 Person-Month (PMs) 7 5 Types of Software Development Project 8 6 Basic COCOMO – Organic Complexity 9 - 10 7 Basic COCOMO – Semidetached Complexity 11 - 12 8 Basic COCOMO – Embedded Complexity 13 - 14 9 Graphical Representation 15 10 Basic COCOMO - Example 16 11 Intermediate COCOMO 17 – 20 12 Complete COCOMO 21 - 22 13 COCOMO - II 23 – 24 14 Queries 25 INDEX
- 3. A Brief Overviewon COCOMO Constructive Cost estimation Model (COCOMO) Proposed by Boehm in 1981 Heuristic Project Estimation Technique Uses both Single and Multivariable estimation
- 4. Stages of COCOMO Accordingto Boehm, COCOMO prescribes a three stage process estimation:
- 5. Basic COCOMO Usedfor quick and slightly rough calculations of Software Costs. Its accuracy is somewhat restricted due to the absence of sufficient factor considerations. Gives only an approximate estimation: Effort = a1*(KLOC)a2 PM Tdev = b1*(Effort)b2 months
- 6. Basic COCOMO KLOC isthe estimated Kilo Lines of Source Code. a1, a2, b1, b2 are the constants for different categories of software products. Tdev is the estimated time to develop the software products Effort estimation is obtained in terms of person-month (PMs)
- 7. Person- Month (Unitto measure Effort) Considered appropriate as developers are assigned for certain months The effort an individual can put in a month. Productivity losses due to time lost are taken into account.
- 8. Types of Software DevelopmentProject According to Boehm, it is again classified into three categories based on Development complexity- Organic Semidetached Embedded
- 9. Basic COCOMO Organic Complexity: Projectshould be well-defined application program Size of the development team is reasonably small Team was experienced in developing similar type of projects
- 10. Basic COCOMO Organic Complexity: Formulafor effort estimation : Effort = 2.4*(KLOC)1.05 PM Formula for development time estimation : Tdev = 2.5*(Effort)0.38 months
- 11. Basic COCOMO Semidetached Complexity: Developmentteam is comprised of both experienced and in-experienced members Team may have limited experience in developing similar type of project and may be unfamiliar with some aspects of the system.
- 12. Basic COCOMO Semidetached Complexity: Formulafor effort estimation : Effort = 3.0*(KLOC)1.12 PM Formula for development time estimation : Tdev = 2.5*(Effort)0.35 months
- 13. Basic COCOMO Embedded Complexity: Developedsoftware is highly coupled to hardware. Stringent regulations on the operational procedures exist. Team may have limited experience on related systems and may be unfamiliar with some aspects of the system.
- 14. Basic COCOMO Embedded Complexity: Formulafor effort estimation : Effort = 3.6*(KLOC)1.20 PM Formula for development time estimation : Tdev = 2.5*(Effort)0.32 months
- 15. Graphical Representation Development Timevs Size Effort vs Size
- 16. Basic COCOMO Example: Supposea project was estimated to be 400 KLOC. Calculate the effort and development time for each of the three model i.e., organic, semi- detached & embedded. Solution: The basic COCOMO equation takes the form: Estimated Size of project= 400 KLOC (i) Organic Mode E = 2.4 * (400)1.05 = 1295.31 PM T = 2.5 * (1295.31)0.38 = 38.07 months (ii) Semidetached Mode E = 3.0 * (400)1.12 = 2462.79 PM T = 2.5 * (2462.79)0.35 = 38.45 months (iii) Embedded Mode E = 3.6 * (400)1.20 = 4772.81 PM T = 2.5 * (4772.8)0.32 = 38 months
- 17. Intermediate COCOMO Itrefines the initial estimate obtained by using the Basic COCOMO. Uses 15 cost drivers that are multiplied with the initial cost and effort estimated by Basic COCOMO. As per Boehm, the scale of cost drivers is in between 0 and 3.
- 18. Intermediate COCOMO The costdrivers can be classified as being attributes of :- Product Computer Personnel Development Environment
- 19. Intermediate COCOMO Product- Required software reliability extent Size of the application database The complexity of the product Computer- Run-time performance constraints Memory constraints The volatility of the virtual machine environment Required turn-about time
- 20. Intermediate COCOMO Development Environment- Use of software tools Application of software engineering methods Required development schedule Personnel- Analyst capability Software engineering capability Applications experience Virtual machine experience Programming language experience
- 21. Complete COCOMO Incorporatesall qualities of the standard version with an assessment of the cost drivers. Consider software product as a bunch of sub-systems. The development team might have no experience on similar type of projects. Development cost is estimated on the sub-systems.
- 22. Complete COCOMO Sixphases of complete COCOMO are: Planning and requirements System structure Complete structure Module code and test Integration and test Cost Constructive model
- 23. COCOMO II COCOMOII incorporates a range of sub-models that produce detailed software estimate. Provide accurate cost and schedule estimates. Provide careful, easy-to-understand definitions of the Model’s input, output and assumptions. Provides a constructive, normative and evolving model.
- 24. COCOMO II Thereare four sub-models of COCOMO II. o Application Composition Model- When software is composed from existing parts. o Early Design Model- When requirements are available but design has not yet started. o Reuse Model- Used to compute the effort of integrating reusable components. o Post-architecture Model- When system architecture is ready and more information is available.
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