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SOFTWARE ENGINNERING

SOFTWARE ENGINNERING. THE CONSTRUCTIVE COST MODEL ( COCOMO MODEL ). OUTLINE OF PRESENTATION. OVERVIEW ARCHITECTURE OF COCOMO MODEL BASIC CONCEPT OF COCOMO MODEL? TYPES OF COCOMO MODEL INTERMEDIATE COCOMO ADVANTAGE OF COCOMO DISADVANTAGE OF COCOMO MULTIPLERS COST DRIVERS LIMITATIONS

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SOFTWARE ENGINNERING

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  1. SOFTWARE ENGINNERING

  2. THE CONSTRUCTIVE COST MODEL (COCOMO MODEL)

  3. OUTLINE OF PRESENTATION • OVERVIEW • ARCHITECTURE OF COCOMO MODEL • BASIC CONCEPT OF COCOMO MODEL? • TYPES OF COCOMO MODEL • INTERMEDIATE COCOMO • ADVANTAGE OF COCOMO • DISADVANTAGE OF COCOMO • MULTIPLERS • COST DRIVERS • LIMITATIONS • CHARACTERISTICS OF COCOMO • CONCULSION

  4. OVERVIEW • The Constructive Cost Model (COCOMO) is an algorithmic software cost estimation model developed by Barry W. Boehm • COCOMO was first published in Boehm's 1981 book Software Engineering Economics[1] as a model for estimating effort, cost, and schedule for software projects

  5. ARCHITECTURE OF COCOMO MODEL

  6. BASIC CONCEPT OF COCOMO MODEL • computes software development effort (and cost) as a function of program size. Program size is expressed in estimated thousands of source lines of code (SLOC) • COCOMO applies to three classes of software projects:

  7. BASIC COCOMO EQUATION TAKE FORM • Effort Applied (E) = ab(KLOC)bb[ man-months ] • Development Time (D) = cb(Effort Applied)db[months] • People required (P) = Effort Applied / Development Time [count]

  8. TYPES OF COCOMO MODEL • Organic projects - "small" teams with "good" experience working with "less than rigid" requirements • Semi-detached projects - "medium" teams with mixed experience working with a mix of rigid and less than rigid requirements • Embedded projects - developed within a set of "tight" constraints. It is also combination of organic and semi-detached projects.(hardware, software, operational, ...)

  9. ITERATIONS COCOMO MODEL

  10. INTERMEDIATE COCOMO • PRODUCT ATRIBUTES • HARDWARE ATRIBUTES • PERSONAL ATRIBUTES • PROJECT ATRIBUTES

  11. PRODUCT ATRIBUTES • Required software reliability • Size of application database • Complexity of the product

  12. HARDWARE ATRIBUTES • Run-time performance constraints • Memory constraints • Volatility of the virtual machine environment • Required turnabout time

  13. PERSONAL ATRIBUTES • Analyst capability • Software engineering capability • Applications experience • Virtual machine experience • Programming language experience

  14. PROJECT ATRIBUTES • Use of software tools • Application of software engineering methods • Required development schedule

  15. GRAPH

  16. COCOMO is transparent, one can see how it works unlike other models such as SLIM Drivers are particularly helpful to the estimator to understand the impact of different factors that affect project costs ADVANTAGES

  17. It is hard to accurately estimate KDSI early on in the project, when most effort estimates are required KDSI, actually, is not a size measure it is a length measure Extremely vulnerable to mis-classification of the development mode Success depends largely on tuning the model to the needs of the organization, using historical data which is not always available DISADVANTAGES

  18. Exponent scale factors

  19. MULTIPLIERS • A total of 17 attributes are multiplied to compute M. • These attributes fall in the following categories • Product attributes • Concerned with required characteristics of the software product being developed. • Computer attributes • Constraints imposed on the software by the hardware platform. • Personnel attributes • Multipliers that take the experience and capabilities of the people working on the project into account. • Project attributes • Concerned with the particular characteristics of the software development project.

  20. Effects of cost drivers

  21. CONCLUSION Software cost estimation is an important part of the software development process. The COCOMO suite(COCOMO II model and its extensions) offers a powerful instrument to predict software costs. Unfortunately not all of the extensions are already calibrated and therefore still experimental. Only the Post-Architecture model is implemented in a calibrated software tool. Despite this disadvantage the COCOMO II suite helps managing software projects. It supports process improvement analyses, tool purchases, architecture changes, component make/buy tradeoffs and decision making process with credible results. Many endeavors were done to measure up to the changes in software life cycles, technologies, components, tools, notations and organizational cultures since the first version of COCOMO Model.

  22. THANK YOU

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