SEC 308 Yazlm Mhendislii Software Project Planning 1

SEC 308 Yazılım Mühendisliği Software Project Planning 1

The Four P’s 0 People — the most important element of a successful project 0 Product — the software to be built 0 Process — the set of framework activities and software engineering tasks to get the job done 0 Project — all work required to make the product a reality People Product Process Project 2

The People: The Stakeholders 0 Five categories of stakeholders 0 Senior managers who define the business issues that often have significant influence on the project. 0 Project (technical) managers who must plan, motivate, organize, and control the practitioners who do software work. 0 Practitioners who deliver the technical skills that are necessary to engineer a product or application. 0 Customers who specify the requirements for the software to be engineered and other stakeholders who have a peripheral interest in the outcome. 0 End-users who interact with the software once it is released for production use. 3

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

The People: Team Leaders 0 Qualities to look for in a team leader 0 Motivation. The ability to encourage (by “push or pull”) technical people to produce to their best ability. 0 Organization. The ability to mold existing processes (or invent new ones) that will enable the initial concept to be translated into a final product. 0 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. 5

The People: The Software Team 0 Seven project factors to consider when structuring a software development team 0 the difficulty of the problem to be solved 0 the size of the resultant program(s) in lines of code or function points 0 the time that the team will stay together (team lifetime) 0 the degree to which the problem can be modularized 0 the required quality and reliability of the system to be built 0 the rigidity of the delivery date 0 the degree of sociability (communication) required for the project 6

The Product Scope 0 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? 0 Information objectives. What customer-visible data objects are produced as output from the software? What data objects are required for input? 0 Function and performance. What function does the software perform to transform input data into output? Are any special performance characteristics to be addressed? 0 Software project scope must be unambiguous and understandable at the management and technical levels. 7

Problem Decomposition 0 Sometimes called partitioning or problem elaboration 0 Once scope is defined … 0 It is decomposed into constituent functions 0 It is decomposed into user-visible data objects or 0 It is decomposed into a set of problem classes 0 Decomposition process continues until all functions or problem classes have been defined 8

The Process 0 Once a process framework has been established 0 Consider project characteristics 0 Determine the degree of rigor required 0 Define a task set for each software engineering activity 0 Task set = 0 Software engineering tasks 0 Work products 0 Quality assurance points 0 Milestones 9

The Project 0 Projects get into trouble when … 0 0 0 0 0 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. 10

To Get to the Essence of a Project 0 Why is the system being developed? 0 What will be done? 0 When will it be accomplished? 0 Who is responsible? 0 Where are they organizationally located? 0 How will the job be done technically and managerially? 0 How much of each resource (e. g. , people, software, tools, database) will be needed? 11

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

Why Do We Measure? 0 assess the status of an ongoing project 0 track potential risks 0 uncover problem areas before they go “critical, ” 0 adjust work flow or tasks, 0 evaluate the project team’s ability to control quality of software work products. 13

Process Metrics 0 Quality-related 0 focus on quality of work products and deliverables 0 Productivity-related 0 Production of work-products related to effort expended 0 Statistical SQA data 0 error categorization & analysis 0 Defect removal efficiency 0 propagation of errors from process activity to activity 0 Reuse data 0 The number of components produced and their degree of reusability 14

Typical Project Metrics 0 Effort/time per software engineering task 0 Errors uncovered per review hour 0 Scheduled vs. actual milestone dates 0 Changes (number) and their characteristics 0 Distribution of effort on software engineering tasks 15

Typical Size-Oriented Metrics 0 0 0 0 errors per KLOC (thousand lines of code) defects per KLOC $ per LOC pages of documentation per KLOC errors person-month errors per review hour LOC person-month $ per page of documentation 16

Typical Function-Oriented Metrics 0 errors per FP (function point) 0 defects per FP 0 $ per FP 0 pages of documentation per FP 0 FP person-month 17

Function-Oriented Metrics 0 FP are computed by FP = count-total * [0. 65 + 0. 01 * Sum(Fi)] 0 count-total is the sum of all FP entries 0 The Fi (i = 1 to 14) are "complexity adjustment values" based on responses to the following questions [ART 85]: 1. Does the system require reliable backup and recovery? 2. Are data communications required? 3. Are there distributed processing functions? 4. Is performance critical? . . . 0 Each of these questions is answered using a scale that ranges from 0 (not important or applicable) to 5 (absolutely essential). 18

Comparing LOC and FP Representative values developed by QSM 19

Object-Oriented Metrics 0 Number of scenario scripts (use-cases) 0 Number of support classes (required to implement the system but are not immediately related to the problem domain) 0 Average number of support classes per key class (analysis class) 0 Number of subsystems (an aggregation of classes that support a function that is visible to the enduser of a system) 20

Web. App Project Metrics 0 Number of static Web pages (the end-user has no control over the content displayed on the page) 0 Number of dynamic Web pages (end-user actions result in customized content displayed on the page) 0 Number of internal page links (internal page links are pointers that provide a hyperlink to some other Web page within the Web. App) 0 Number of persistent data objects 0 Number of external systems interfaced 0 Number of static content objects 0 Number of dynamic content objects 0 Number of executable functions 21

Measuring Quality 0 Correctness — the degree to which a program operates according to specification 0 Maintainability—the degree to which a program is amenable to change 0 Integrity—the degree to which a program is impervious to outside attack 0 Usability—the degree to which a program is easy to use 22

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. 23

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! 24

Project Planning Task Set 0 Establish project scope 0 Determine feasibility 0 Analyze risks 0 Define required resources 0 Determine required human resources 0 Define reusable software resources 0 Identify environmental resources 25

Project Planning Task Set (cont. ) 0 Estimate cost and effort 0 Decompose the problem 0 Develop two or more estimates using size, function points, process tasks or use-cases 0 Reconcile the estimates 0 Develop a project schedule 0 Establish a meaningful task set 0 Define a task network 0 Use scheduling tools to develop a timeline chart 0 Define schedule tracking mechanisms 26

Estimation 0 Estimation of resources, cost, and schedule for a software engineering effort requires 0 experience 0 access to good historical information (metrics) 0 the courage to commit to quantitative predictions when qualitative information is all that exists 0 Estimation carries inherent risk and this risk leads to uncertainty 27

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

What is Scope? 0 Software scope describes 0 the functions and features that are to be delivered to end-users 0 the data that are input and output 0 the “content” that is presented to users as a consequence of using the software 0 the performance, constraints, interfaces, and reliability that bound the system. 0 Scope is defined using one of two techniques: 0 A narrative description of software scope is developed after communication with all stakeholders. 0 A set of use-cases is developed by end-users. 29

Resource Estimation 0 Three major categories of software engineering resources 0 People 0 Development environment 0 Reusable software components 0 Often neglected during planning but become a paramount concern during the construction phase of the software process 0 Each resource is specified with 0 0 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 30

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 31

Human Resources 0 Planners need to select the number and the kind of people skills needed to complete the project 0 They need to specify the organizational position and job specialty for each person 0 Small projects of a few person-months may only need one individual 0 Large projects spanning many person-months or years require the location of the person to be specified also 0 The number of people required can be determined only after an estimate of the development effort 32

Development Environment Resources 0 A software engineering environment (SEE) incorporates hardware, software, and network resources that provide platforms and tools to develop and test software work products 0 Most software organizations have many projects that require access to the SEE provided by the organization 0 Planners must identify the time window required for hardware and software and verify that these 33 resources will be available

Reusable Software Resources 0 Off-the-shelf components 0 Components are from a third party or were developed for a previous project 0 Ready to use; fully validated and documented; virtually no risk 0 Full-experience components 0 Components are similar to the software that needs to be built 0 Software team has full experience in the application area of these components 0 Modification of components will incur relatively low risk 34

Reusable Software Resources 0 Partial-experience components 0 Components are related somehow to the software that needs to be built but will require substantial modification 0 Software team has only limited experience in the application area of these components 0 Modifications that are required have a fair degree of risk 0 New components 0 Components must be built from scratch by the software team specifically for the needs of the current project 0 Software team has no practical experience in the application area 0 Software development of components has a high degree 35 of risk

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

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

Problem-Based Estimation 0 Start with a bounded statement of scope 0 Decompose the software into problem functions that can each be estimated individually 0 Compute an LOC or FP value for each function 0 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) 0 Combine function estimates to produce an overall estimate for the entire project 38

Problem-Based Estimation 0 In general, the LOC/pm and FP/pm metrics should be computed by project domain 0 Important factors are team size, application area, and complexity 0 LOC and FP estimation differ in the level of detail required for decomposition with each value 0 For LOC, decomposition of functions is essential and should go into considerable detail (the more detail, the more accurate the estimate) 0 For FP, decomposition occurs for the five information domain characteristics and the 14 adjustment factors 0 External inputs, external outputs, external inquiries, internal logical files, external interface files 39

Problem-Based Estimation 0 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) 0 Then the expected size value S is computed as follows: S = (Sopt + 4 Sm + Spess)/6 0 Historical LOC or FP data is then compared to S in order to cross-check it 40

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. 41

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. 42

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

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- 44 months.

Process-Based Estimation 0 0 0 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 45

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 0 0 0 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) 46

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

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. 48

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

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 usecase estimate and the historical productivity data, the total estimated project cost is $552, 000 and the estimated effort is 68 person-months. 50

Empirical Estimation Models General form: exponent effort = tuning coefficient * size usually derived as person-months of effort required either a constant or a number derived based on complexity of project empirically derived usually LOC but may also be function point 51

COCOMO-II 0 COCOMO II is actually a hierarchy of estimation models that address the following areas: 0 Application composition model. Used during the early stages of software engineering, when prototyping of user interfaces, consideration of software and system interaction, assessment of performance, and evaluation of technology maturity are paramount. 0 Early design stage model. Used once requirements have been stabilized and basic software architecture has been established. 0 Post-architecture-stage model. Used during the construction of the software. 52

The Software Equation A dynamic multivariable model E = [LOC x B 0. 333/P]3 x (1/t 4) where E = effort in person-months or person-years t = project duration in months or years B = “special skills factor” P = “productivity parameter” 53

Estimation for OO Projects-I 0 Develop estimates using effort decomposition, FP analysis, and any other method that is applicable for conventional applications. 0 Using object-oriented analysis modeling (Chapter 8), develop use-cases and determine a count. 0 From the analysis model, determine the number of key classes (called analysis classes in Chapter 8). 0 Categorize the type of interface for the application and develop a multiplier for support classes: 0 0 0 Interface type Multiplier No GUI 2. 0 Text-based user interface 2. 25 GUI 2. 5 Complex GUI 3. 0 54

Estimation for OO Projects-II 0 Multiply the number of key classes (step 3) by the multiplier to obtain an estimate for the number of support classes. 0 Multiply the total number of classes (key + support) by the average number of work-units per class. Lorenz and Kidd suggest 15 to 20 person-days per class. 0 Cross check the class-based estimate by multiplying the average number of work-units per use-case 55

The Make-Buy Decision 56

Computing Expected Cost expected cost = (path probability) x (estimated path cost) i i For example, the expected cost to build is: expected cost = 0. 30 ($380 K) + 0. 70 ($450 K) build = $429 K similarly, expected cost = $382 K reuse expected cost = $267 K buy expected cost = $410 K contr 57

Why Are Projects Late? 0 an unrealistic deadline established by someone outside the software development group 0 changing customer requirements that are not reflected in schedule changes; 0 an honest underestimate of the amount of effort and/or the number of resources that will be required to do the job; 0 predictable and/or unpredictable risks that were not considered when the project commenced; 0 technical difficulties that could not have been foreseen in advance; 0 human difficulties that could not have been foreseen in advance; 0 miscommunication among project staff that results in delays; 0 a failure by project management to recognize that the project is falling behind schedule and a lack of action to correct the problem 58

Effort and Delivery Time 59

Scheduling Principles • “front end” activities 40 -50% 15 -20% – – customer communication analysis design review and modification • construction activities – coding or code generation • testing and installation – unit, integration – white-box, black box – regression 30 -40% 60

40 -20 -40 Distribution of Effort 0 A recommended distribution of effort across the software process is 40% (analysis and design), 20% (coding), and 40% (testing) 0 Work expended on project planning rarely accounts for more than 2 - 3% of the total effort 0 Requirements analysis may comprise 10 - 25% 0 Effort spent on prototyping and project complexity may increase this 0 Software design normally needs 20 – 25% 0 Coding should need only 15 - 20% based on the effort applied to software design 0 Testing and subsequent debugging can account for 30 - 40% 0 Safety or security-related software requires more time for testing 61

Basic Principles for Project Scheduling 0 Compartmentalization 0 The project must be compartmentalized into a number of manageable activities, actions, and tasks; both the product and the process are decomposed 0 Interdependency 0 The interdependency of each compartmentalized activity, action, or task must be determined 0 Some tasks must occur in sequence while others can occur in parallel 0 Some actions or activities cannot commence until the work product produced by another is available 62

Basic Principles for Project Scheduling 0 Time allocation 0 Each task to be scheduled must be allocated some number of work units 0 In addition, each task must be assigned a start date and a completion date that are a function of the interdependencies 0 Start and stop dates are also established based on whether work will be conducted on a full-time or part-time basis 0 Effort validation 0 Every project has a defined number of people on the team 0 As time allocation occurs, the project manager must ensure that no more than the allocated number of people have been scheduled at any given time 63

Basic Principles for Project Scheduling 0 Defined responsibilities 0 Every task that is scheduled should be assigned to a specific team member 0 Defined outcomes 0 Every task that is scheduled should have a defined outcome for software projects such as a work product or part of a work product 0 Work products are often combined in deliverables 0 Defined milestones 0 Every task or group of tasks should be associated with a project milestone 0 A milestone is accomplished when one or more work products has been reviewed for quality and has been approved 64

Relationship Between People and Effort 0 Common management myth: If we fall behind schedule, we can always add more programmers and catch up later in the project 0 This practice actually has a disruptive effect and causes the schedule to slip even further 0 The added people must learn the system 0 The people who teach them are the same people who were earlier doing the work 0 During teaching, no work is being accomplished 0 Lines of communication (and the inherent delays) increase for each new person added 65

Factors that Influence a Project’s Schedule 0 Size of the project 0 Number of potential users 0 Mission criticality 0 Application longevity 0 Stability of requirements 0 Ease of customer/developer communication 0 Maturity of applicable technology 0 Performance constraints 0 Embedded and non-embedded characteristics 0 Project staff 0 Reengineering factors 66

Purpose of a Task Network 0 Also called an activity network 0 It is a graphic representation of the task flow for a project 0 It depicts task length, sequence, concurrency, and dependency 0 Points out inter-task dependencies to help the manager ensure continuous progress toward project completion 0 The critical path 0 A single path leading from start to finish in a task network 0 It contains the sequence of tasks that must be completed on schedule if the project as a whole is to be completed on schedule 0 It also determines the minimum duration of the project 67

Example Task Network Task F 2 Task B 3 Task A 3 Task C 7 Task D 5 Task E 8 Task G 3 Task I 4 Task J 5 Task K 3 Task L 10 Task H 5 Task N 2 Task M 0 Where is the critical path and what tasks are on it? 68

Example Task Network Task F 2 Task B 3 Task A 3 Task C 7 Task D 5 Task E 8 Task G 3 Task I 4 Task J 5 Task K 3 Task L 10 Task H 5 Task N 2 Task M 0 Critical path: A-B-C-E-K-L-M-N 69

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Timeline Charts Tasks Week 1 Week 2 Week 3 Week 4 Week n Task 1 Task 2 Task 3 Task 4 Task 5 Task 6 Task 7 Task 8 Task 9 Task 10 Task 11 Task 12 71

Use Automated Tools to Derive a Timeline Chart 72

Example Timeline Charts 73

Proposed Tasks for a Long-Distance Move of 8, 000 lbs of Household Goods Make decision to move Drive truck from origin to destination Unload truck Arrange for workers to load truck Pack household goods Arrange for workers to unload truck Determine date to move out or move in Decide on type/size of rental truck Return truck and supplies Reserve rental truck and supplies Find lodging with space to park truck Pick up rental truck Determine destination location Make lodging reservations Plan travel route and overnight stops Load truck Get money to pay for the move Lease or buy home at destination Arrange for person to drive truck/car • Where is the critical path and what tasks are on it? • Given a firm start date, on what date will the project be completed? • Given a firm stop date, when is the latest date that the project must start by? 74

2. Get money to pay for the move 3. Determine date to move out or move in Proposed Tasks for a Long-Distance Move of 8, 000 lbs of Household Goods 12. Plan travel 13. Find lodging route and with space overnight stops to park truck 4. Determine destination location 14. Make lodging reservations 5. Lease or buy home at destination 6. Decide on type/size of rental truck 7. Arrange for workers to load truck 8. Arrange for person to drive truck/car 9. Arrange for workers to unload truck 10. Pack household goods 18. Drive truck from origin to destination 11. Milestone 15. Reserve rental truck and supplies 16. Pick up rental truck 17. Load truck 19. Unload truck 20. Return truck and supplies • Where is the critical path and what tasks are on it? • Given a firm start date, on what date will the project be completed? • Given a firm stop date, when is the latest date that the project must 75 start by?

Timeline Chart for Long Distance Move 76