Process Modeling

CS 4320

Fall 2003

Process Difficulties

SW not a production line Each project is different—even within the

same company No universally accepted processes for SE Shelfware No Training Resistance (is not always futile)

Levels of Process (Humphrey)

U – Universe (Life Cycles) W – Worldly (sequence of tasks and prereq) A – Atomic (enormously detailed) Can also be viewed as:

– Policies– Procedures– Standards

Example Levels (Humphrey)

U – Waterfall Model W – Critical Design Review held before entry

into implementation, Issues are submitted to…

A – Actual checklist for critical design review

Levels of Process (Text)

Meta-Object Facility – Model of Model Notation

Process Metamodel – Model Notation (UML) Process Model – Model itself (RUP) Performing Process – What we actually do

Process Decomposition (ISO 12207)

Process (High Level Category) Activity (Major Common Categories) Task (Actual Work Tasks)

Examples

Process: Software Requirements Analysis Activity: Complete Requirements Spec Task: Conduct Requirements Review

Primary– Acquisition (Let the contract)– Supply (Fulfill the contract)– Development (Make the product)– Operation (Operate the product in a system) – Maintenance (Correct/Modify the product)

ISO Std 12207

ISO Std 12207

Organizational Processes– Management– Infrastructure– Improvement– Human Resource– Asset Management– Reuse Program Management– Domain Engineering

Supporting– Documentation– Configuration Management– Quality Assurance– Verification– Validation– Joint Review– Audit– Problem Resolution– Usability– Product Evaluation

ISO Std 12207

Development Activities– Process Implementation– System Requirements Analysis– System Architectural Design– Software Requirements Analysis– Software Architectural Design– Software Detailed Design– Software Coding and Testing– Software Integration– Software Qualification Testing– System Integration– System Qualification Testing– Software Installation– Software Acceptance Support

ISO Std 12207

U Level Software Life Cycle Models

Examples of Models:– Code-and-Fix – Waterfall– Incremental, Design to Sched– Spiral– Evolutionary Proto, Delivery

Life-cycle: A project-specific, sequenced mapping of activities. May be a “standard” model adapted for your specific project.

Choose Right One for project and Tailor it Table 7-1 (Rapid Development) Choosing a life cycle model

Issues in Selecting Life Cycle

How well are requirements understood? How “firm” are requirements? How long can you go without “something”? How much risk is there? How hard is it to use the model? How much overhead is required? Do I have an artificial schedule?

Process Architecture (ETVX)

Entry Process Name ExitInput Output

Feedback OutFeedback In

Measures

Resources Needed

Activity List

N

Interfaces Interfaces

Filled out cell

MarketingInputs Project Planning

Concept Approval

1. Approved SDP2. Approved WBS3. Project Init in

MS

Requests forClarification

ScopeChanges

ResourceSchedule Info

1. Estimate Effort2. Prepare WBS3. Prepare Schedule

001

MS Project

Interface: email phone formal memo

Interface: Approved ECP

Measurement:Person-MonthsKLOC

Class Exercise, Process Models

Pick a Life Cycle Model……. And let’s model it…

The Infosys Process Description

1. Overview2. Participants3. Entry Criteria4. Exit Criteria5. Inputs6. Activities7. Exit Criteria8. Outputs9. Measurements10. Special Considerations11. References