SEC 308 Yazılım Mühendisliği Software Project Planning

1. SEC 308 Yazılım MühendisliğiSoftware Project Planning

2. The Four P’s • People— the most important element of a successful project • Product— the software to be built • Process — the set of framework activities and software engineering tasks to get the job done • Project— all work required to make the product a reality Project Process Product People

3. The People: The Stakeholders • Five categories of stakeholders • Senior managerswho define the business issues that often have significant influence on the project. • Project (technical) managerswho must plan, motivate, organize, and control the practitioners who do software work. • Practitionerswho deliver the technical skills that are necessary to engineer a product or application. • Customerswho specify the requirements for the software to be engineered and other stakeholders who have a peripheral interest in the outcome. • End-userswho interact with the software once it is released for production use.

4. How to lead? How to organize? How to collaborate? How to motivate? How to create good ideas? Software Teams

5. The People: Team Leaders • Qualities to look for in a team leader • Motivation. The ability to encourage (by “push or pull”) technical people to produce to their best ability. • Organization. The ability to mold existing processes (or invent new ones) that will enable the initial concept to be translated into a final product. • Ideas or innovation. The ability to encourage people to create and feel creative even when they must work within bounds established for a particular software product or application.

6. The People: The Software Team • Seven project factors to consider when structuring a software development team • the difficulty of the problemto be solved • the size of the resultant program(s) in lines of code or function points • the time that the team will stay together(team lifetime) • the degree to which the problem can be modularized • the required quality and reliability of the system to be built • the rigidity of the delivery date • the degree of sociability (communication) required for the project

7. The Product Scope • Scope • Context. How does the software to be built fit into a larger system, product, or business context and what constraints are imposed as a result of the context? • Information objectives. What customer-visible data objectsare produced as output from the software? What data objects are required for input? • Function and performance.What function does the software perform to transform input data into output? Are any special performance characteristics to be addressed? • Software project scope must be unambiguous and understandable at the management and technical levels.

8. Problem Decomposition • Sometimes called partitioning or problem elaboration • Once scope is defined … • It is decomposed into constituent functions • It is decomposed into user-visible data objects or • It is decomposed into a set of problem classes • Decomposition process continues until all functions or problem classes have been defined

9. The Process • Once a process framework has been established • Consider project characteristics • Determine the degree of rigor required • Define a task set for each software engineering activity • Task set = • Software engineering tasks • Work products • Quality assurance points • Milestones

10. The Project • Projects get into trouble when … • Software people don’t understand their customer’s needs. • The product scope is poorly defined. • Changes are managed poorly. • The chosen technology changes. • Business needs change [or are ill-defined]. • Deadlines are unrealistic. • Users are resistant. • Sponsorship is lost [or was never properly obtained]. • The project team lacks people with appropriate skills. • Managers [and practitioners] avoid best practices and lessons learned.

11. To Get to the Essence of a Project • Why is the system being developed? • What will be done? • When will it be accomplished? • Who is responsible? • Where are they organizationally located? • How will the job be done technically and managerially? • How much of each resource (e.g., people, software, tools, database) will be needed?

12. A Good Manager Measures process process metrics project metrics measurement product metrics product What do we use as a basis? • size? • function?

13. Why Do We Measure? • assess the status of an ongoing project • track potential risks • uncover problem areas before they go “critical,” • adjust work flow or tasks, • evaluate the project team’s ability to control quality of software work products.

14. Process Metrics • Quality-related • focus on quality of work products and deliverables • Productivity-related • Production of work-products related to effort expended • Statistical SQA data • error categorization & analysis • Defect removal efficiency • propagation of errors from process activity to activity • Reuse data • The number of components produced and their degree of reusability

15. Typical Project Metrics • Effort/time per software engineering task • Errors uncovered per review hour • Scheduled vs. actual milestone dates • Changes (number) and their characteristics • Distribution of effort on software engineering tasks

16. Typical Size-Oriented Metrics • errors per KLOC (thousand lines of code) • defects per KLOC • $ per LOC • pages of documentation per KLOC • errors per person-month • errors per review hour • LOC per person-month • $ per page of documentation

17. Typical Function-Oriented Metrics • errors per FP (function point) • defects per FP • $ per FP • pages of documentation per FP • FP per person-month

18. Function-Oriented Metrics • FP are computed by FP = count-total * [0.65 + 0.01 * Sum(Fi)] • count-total is the sum of all FP entries • The Fi (i = 1 to 14) are "complexity adjustment values" based on responses to the followingquestions [ART85]: 1. Does the system require reliable backup and recovery? 2. Are data communications required? 3. Are there distributed processing functions? 4. Is performance critical? ... • Each of these questions is answered using a scale that ranges from 0 (not importantor applicable) to 5 (absolutely essential).

19. Comparing LOC and FP Representative values developed by QSM

20. Object-Oriented Metrics • Number ofscenario scripts(use-cases) • Number of support classes (required to implement the system but are not immediately related to the problem domain) • Average number of support classes per key class(analysis class) • Number ofsubsystems (an aggregation of classes that support a function that is visible to the end-user of a system)

21. WebApp Project Metrics • Number of static Web pages (the end-user has no control over the content displayed on the page) • Number of dynamic Web pages(end-user actions result in customized content displayed on the page) • Number of internal page links (internal page links are pointers that provide a hyperlink to some other Web page within the WebApp) • Number ofpersistent data objects • Number ofexternal systems interfaced • Number of static content objects • Number of dynamic content objects • Number ofexecutable functions

22. Measuring Quality • Correctness— the degree to which a program operates according to specification • Maintainability—the degree to which a program is amenable to change • Integrity—the degree to which a program is impervious to outside attack • Usability—the degree to which a program is easy to use

23. Defect Removal Efficiency DRE = E /(E + D) • where: • E is the number of errors found before delivery of the software to the end-user • D is the number of defects found after delivery.

24. Software Project Planning The overall goal of project planning is to establish a pragmatic strategy for controlling, tracking, and monitoring a complex technical project. Why? So the end result gets done on time, with quality!

25. Project Planning Task Set • Establish project scope • Determine feasibility • Analyze risks • Define required resources • Determine requiredhuman resources • Define reusable software resources • Identify environmental resources

26. Project Planning Task Set (cont.) • Estimate cost and effort • Decompose the problem • Develop two or more estimates using size, function points, process tasks or use-cases • Reconcile the estimates • Develop a project schedule • Establish a meaningful task set • Define a task network • Use scheduling tools to develop a timeline chart • Define schedule tracking mechanisms

27. Estimation • Estimation of resources, cost, and schedule for a software engineering effort requires • experience • access to good historical information (metrics) • the courage to commit to quantitative predictions when qualitative information is all that exists • Estimation carries inherent risk and this risk leads to uncertainty

28. Write it Down! Project Scope Estimates Risks Schedule Control strategy Software Project Plan

29. What is Scope? • Software scope describes • the functions and features that are to be delivered to end-users • the data that are input and output • the “content” that is presented to users as a consequence of using the software • the performance, constraints, interfaces, and reliability that bound the system. • Scope is defined using one of two techniques: • A narrative description of software scope is developed after communication with all stakeholders. • A set of use-cases is developed by end-users.

30. Resource Estimation • Three major categories of software engineering resources • People • Development environment • Reusable software components • Often neglected during planning but become a paramount concern during the construction phase of the software process • Each resource is specified with • A description of the resource • A statement of availability • The time when the resource will be required • The duration of time that the resource will be applied Time window

31. Categories of Resources • People • Number required • Skills required • Geographical location • Development Environment • Software tools • Computer hardware • Network resources The Project • Reusable Software Components • Off-the-shelf components • Full-experience components • Partial-experience components • New components

32. Human Resources • Planners need to select the number and the kind of people skills needed to complete the project • They need to specify the organizational position and job specialty for each person • Small projects of a few person-months may only need one individual • Large projects spanning many person-months or years require the location of the person to be specified also • The number of people required can be determined only after an estimate of the development effort

33. Development Environment Resources • A software engineering environment (SEE) incorporates hardware, software, and network resources that provide platforms and tools to develop and test software work products • Most software organizations have many projects that require access to the SEE provided by the organization • Planners must identify the time window required for hardware and software and verify that these resources will be available

34. Reusable Software Resources • Off-the-shelf components • Components are from a third party or were developed for a previous project • Ready to use; fully validated and documented; virtually no risk • Full-experience components • Components are similar to the software that needs to be built • Software team has full experience in the application area of these components • Modification of components will incur relatively low risk

35. Reusable Software Resources • Partial-experience components • Components are related somehow to the software that needs to be built but will require substantial modification • Software team has only limited experience in the application area of these components • Modifications that are required have a fair degree of risk • New components • Components must be built from scratch by the software team specifically for the needs of the current project • Software team has no practical experience in the application area • Software development of components has a high degree of risk

36. Estimation Techniques • Past (similar) project experience • Conventional estimation techniques • task breakdown and effort estimates • size (e.g., FP) estimates • Empirical models • Automated tools

37. Functional Decomposition Statement of Scope functional decomposition Perform a Grammatical “parse”

38. Problem-Based Estimation • Start with a bounded statement of scope • Decompose the software into problem functions that can each be estimated individually • Compute an LOC or FP value for each function • Derive cost or effort estimates by applying the LOC or FP values to your baseline productivity metrics (e.g., LOC/person-month or FP/person-month) • Combine function estimates to produce an overall estimate for the entire project

39. Problem-Based Estimation • In general, the LOC/pm and FP/pm metrics should be computed by project domain • Important factors are team size, application area, and complexity • LOC and FP estimation differ in the level of detail required for decomposition with each value • For LOC, decomposition of functions is essential and should go into considerable detail (the more detail, the more accurate the estimate) • For FP, decomposition occurs for the five information domain characteristics and the 14 adjustment factors • External inputs, external outputs, external inquiries, internal logical files, external interface files

40. Problem-Based Estimation • For both approaches, the planner uses lessons learned to estimate an optimistic, most likely, and pessimistic size value for each function or count (for each information domain value) • Then the expected size value S is computed as follows:S = (Sopt + 4Sm + Spess)/6 • Historical LOC or FP data is then compared to S in order to cross-check it

41. Example: LOC Approach Average productivity for systems of this type = 620 LOC/pm. Burdened labor rate =$8000 per month, the cost per line of code is approximately $13. Based on the LOC estimate and the historical productivity data, the total estimated project cost is $431,000 and the estimated effort is 54 person-months.

42. Example: FP Approach The estimated number of FP is derived: FPestimated = count-total * [0.65 + 0.01 * Sum(Fi)] (see next) FPestimated = 375 organizational average productivity = 6.5 FP/pm. burdened labor rate = $8000 per month, the cost per FP is approximately $1230. Based on the FP estimate and the historical productivity data, the total estimated project cost is $461,000 and the estimated effort is 58 person-months.

43. Complexity Adjustment Factor • Answer the factors using a scale that ranges from 0 (not important or applicable) to 5 (absolutely essential) • Sum(Fi)=52 Factor Value • Backup and recovery 4 • Data communications 2 • Distributed processing 0 • Performance critical 4 • Existing operating environment 3 • On-line data entry 4 • Input transaction over multiple screens 5 • Master files updated on-line 3 • Information domain values complex 5 • Internal processing complex 5 • Code designed for reuse 4 • Conversion/installation in design 3 • Multiple installations 5 • Application designed for change 5

44. Example: FP Approach The estimated number of FP is derived: FPestimated = count-total * [0.65 + 0.01 * Sum(Fi)] FPestimated = 375 organizational average productivity = 6.5 FP/pm. burdened labor rate = $8000 per month, the cost per FP is approximately $1230. Based on the FP estimate and the historical productivity data, the total estimated project cost is $461,000 and the estimated effort is 58 person-months.

45. Process-Based Estimation • Identify the set of functions that the software needs to perform as obtained from the project scope • Identify the series of framework activities that need to be performed for each function • Estimate the effort (in person months) that will be required to accomplish each software process activity for each function

46. Process-Based Estimation • Apply average labor rates (i.e., cost/unit effort) to the effort estimated for each process activity • Compute the total cost and effort for each function and each framework activity (See table in Pressman, p. 655) • Compare the resulting values to those obtained by way of the LOC and FP estimates • If both sets of estimates agree, then your numbers are highly reliable • Otherwise, conduct further investigation and analysis concerning the function and activity breakdown This is the most commonly used of the two estimation techniques (problem and process)

47. Process-Based Estimation Obtained from “process framework” framework activities application functions Effort required to accomplish each framework activity for each application function

48. Process-Based Estimation Example Based on an average burdened labor rate of $8,000 per month, the total estimated project cost is $368,000 and the estimated effort is 46 person-months.

49. Tool-Based Estimation project characteristics calibration factors LOC/FP data

50. Estimation with Use-Cases Using 620 LOC/pm as the average productivity for systems of this type and a burdened labor rate of $8000 per month, the cost per line of code is approximately $13. Based on the use-case estimate and the historical productivity data, the total estimated project cost is $552,000 and the estimated effort is 68 person-months.