Software project planning in software engineering by ram k paliwal unit 2
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The document outlines the principles of software project planning and estimation, emphasizing the need for frameworks to provide reasonable resource, cost, and schedule estimates. It discusses the inherent uncertainties in software estimation due to various influencing factors and presents systematic approaches to improve estimation accuracy. Several sizing methods for software projects, including fuzzy logic sizing and function point sizing, are detailed, highlighting the importance of accurate size estimation for project planning.
Software project planning in software engineering by ram k paliwal unit 2
- 1. Software Engineering- Unit 2 SOFTWARE PROJECT PLANNING IN SOFTWARE ENGINEERING BY RAM K PALIWAL – PART 1 8/31/2019 RAM K PALIWAL - SOFTWARE PROJECT ESTIMATION IN SOFTWARE ENGINEERING - UNIT 1 1
- 2. Software Project Planning Software project planning is to provide a framework that enables the manager to make reasonable estimates of ◦ Resources ◦ Cost ◦ Schedule. In addition, estimates should attempt to define best-case and worst-case scenarios so that project outcomes can be bounded. Although there is an inherent degree of uncertainty, the software team embarks on a plan that has been established as a consequence of these tasks. Therefore, the plan must be adapted and updated as the project proceeds. 8/31/2019 RAM K PALIWAL - SOFTWARE PROJECT ESTIMATION IN SOFTWARE ENGINEERING - UNIT 1 2
- 3. Software Project Estimation Software cost and effort estimation will never be an exact science. Too many variables — ◦Human ◦Technical ◦Environmental ◦Political Above variable affect the ultimate cost of software and effort applied to develop it. However, software project estimation can be transformed from a black art to a series of systematic steps that provide estimates with acceptable risk. 8/31/2019 RAM K PALIWAL - SOFTWARE PROJECT ESTIMATION IN SOFTWARE ENGINEERING - UNIT 1 3
- 4. Software Project Estimation To achieve reliable cost and effort estimates, a number of options arise: ◦ Delay estimation until late in the project (obviously, we can achieve 100 percent accurate estimates after the project is complete!). ◦ Base estimates on similar projects that have already been completed. ◦ Use relatively simple decomposition techniques to generate project cost and effort estimates. ◦ Use one or more empirical models for software cost and effort estimation. 8/31/2019 RAM K PALIWAL - SOFTWARE PROJECT ESTIMATION IN SOFTWARE ENGINEERING - UNIT 1 4
- 5. Software Project Estimation Automated estimation tools implement one or more decomposition techniques or empirical models and provide an attractive option for estimating. In such systems, the characteristics of the development organization (e.g., experience, environment) and the software to be developed are described. Cost and effort estimates are derived from these data. Each of the viable software cost estimation options is only as good as the historical data used to seed the estimate. If no historical data exist, costing rests on a very shaky foundation. 8/31/2019 RAM K PALIWAL - SOFTWARE PROJECT ESTIMATION IN SOFTWARE ENGINEERING - UNIT 1 5
- 6. Software Project Estimation Size Estimation: The accuracy of a software project estimate is predicated on a number of things: (1) the degree to which you have properly estimated the size of the product to be built; (2) the ability to translate the size estimate into human effort, calendar time, and dollars (a function of the availability of reliable software metrics from past projects); (3) the degree to which the project plan reflects the abilities of the software team; and (4) the stability of product requirements and the environment that supports the software engineering effort. 8/31/2019 RAM K PALIWAL - SOFTWARE PROJECT ESTIMATION IN SOFTWARE ENGINEERING - UNIT 1 6
- 7. Software Project Estimation In this section, I consider the software sizing problem. Because a project estimate is only as good as the estimate of the size of the work to be accomplished, sizing represents your first major challenge as a planner. In the context of project planning, size refers to a quantifiable outcome of the software project. ◦ If a direct approach is taken, size can be measured in lines of code (LOC). ◦ If an indirect approach is chosen, size is represented as function points (FP). 8/31/2019 RAM K PALIWAL - SOFTWARE PROJECT ESTIMATION IN SOFTWARE ENGINEERING - UNIT 1 7
- 8. Software Project Estimation Size Estimation: Putnam and Myers suggest four different approaches to the sizing problem: 1. Fuzzy Logic Sizing 2. Function Point Sizing 3. Standard Component Sizing 4. Change Sizing 8/31/2019 RAM K PALIWAL - SOFTWARE PROJECT ESTIMATION IN SOFTWARE ENGINEERING - UNIT 1 8
- 9. Software Project Estimation 1. Fuzzy logic sizing This approach uses the approximate reasoning techniques that are the cornerstone of fuzzy logic. To apply this approach, the planner must identify the type of application, establish its magnitude on a qualitative scale, and then refine the magnitude within the original range. 2. Function point sizing The planner develops estimates of the information domain characteristics. 8/31/2019 RAM K PALIWAL - SOFTWARE PROJECT ESTIMATION IN SOFTWARE ENGINEERING - UNIT 1 9
- 10. Software Project Estimation 3. Standard component sizing Software is composed of a number of different “standard components” that are generic to a particular application area. For example, the standard components for an information system are subsystems, modules, screens, reports, interactive programs, batch programs, files, LOC, and object-level instructions. The project planner estimates the number of occurrences of each standard component and then uses historical project data to estimate the delivered size per standard component. 8/31/2019 RAM K PALIWAL - SOFTWARE PROJECT ESTIMATION IN SOFTWARE ENGINEERING - UNIT 1 10
- 11. Software Project Estimation 4. Change sizing This approach is used when a project encompasses the use of existing software that must be modified in some way as part of a project. The planner estimates the number and type (e.g., reuse, adding code, changing code, deleting code) of modifications that must be accomplished. Putnam and Myers suggest that the results of each of these sizing approaches be combined statistically to create a three-point or expected-value estimate. 8/31/2019 RAM K PALIWAL - SOFTWARE PROJECT ESTIMATION IN SOFTWARE ENGINEERING - UNIT 1 11
- 12. References: https://www.geeksforgeeks.org/software-engineering-software-crisis/ 7th edition Software Engineering A Practitioners Approach by Roger S. Pressman 8/31/2019 RAM K PALIWAL - SOFTWARE PROJECT ESTIMATION IN SOFTWARE ENGINEERING - UNIT 1 12
Editor's Notes
- #5: 1. Unfortunately, the first option, however attractive, is not practical. Cost estimates must be provided up-front. However, you should recognize that the longer you wait, the more you know, and the more you know, the less likely you are to make serious errors in your estimates. 2. The second option can work reasonably well, if the current project is quite similar to past efforts and other project influences (e.g., the customer, business conditions, the software engineering environment, deadlines) are roughly equivalent. Unfortunately, past experience has not always been a good indicator of future results. 3. The remaining options are viable approaches to software project estimation. Ideally, the techniques noted for each option should be applied in tandem; each used as a cross-check for the other. Decomposition techniques take a divide-and-conquer approach to software project estimation. By decomposing a project into major functions and related software engineering activities, cost and effort estimation can be performed in a stepwise fashion. 4. Empirical estimation models can be used to complement decomposition techniques and offer a potentially valuable estimation approach in their own right. A model is based on experience (historical data) and takes the form
- #7: A model is based on experience (historical data) and takes the form D = f(Vi) where D is one of a number of estimated values (e.g., effort, cost, project duration) and Vi are selected independent parameters (e.g., estimated LOC or FP).