Software Engineering: Process Models and Flows

Generic Process Model

• Software process refers to a framework encompassing umbrella activities and process framework
• Process framework constitutes framework activities, software engineering actions, and task sets
• Framework activity involves software engineering actions
• Tasks include work tasks, work products, quality assurance points, and project milestones
• Umbrella activities are activities that occur throughout the software process

Process Flow

• Process flow is represented in four methods
• Linear process flow involves sequential steps of communication, planning, modeling, construction, and deployment
• Iterative process flow includes feedback loops to previous stages
• Evolutionary process flow emphasizes incremental releases and feedback
• Parallel process flow executes multiple stages concurrently

Task Set Identification

• Task sets define the specific work required to achieve the objectives of software engineering action
• Task set includes a list of tasks to be accomplished, work products to be produced and the quality assurance filters to be applied

Process Patterns

• Process pattern describes a process-related problem encountered during software engineering work
• It identifies the environment and suggests proven solutions to the problem
• Process pattern provides consistent method for describing problem solutions in the context of the software process

Process Pattern Types

• Stage patterns define a problem associated with a process framework activity
• Task patterns define a problem associated with a software engineering action or work task relevant to successful software engineering practice
• Phase patterns define the sequence of framework activities that occur with the process

Process Assessment and Improvement

• Standard CMMI Assessment Method for Process Improvement (SCAMPI provides a process assessment model with five phases: initiating, diagnosing, establishing, acting, and learning
• CMM-Based Appraisal for Internal Process Improvement (CBA IPI) helps to diagnoses a software organization's maturity using the SEI CMM
• SPICE (ISO/IEC15504) assists organizations in developing objective evaluations of the efficacy of any defined software process
• ISO 9001:2000 improves overall quality regardless of the products, systems, or services

Prescriptive Models

• Prescriptive process models advocate an orderly approach to software engineering
• Questions arise on if prescriptive process models are appropriate for a constantly changing field
• Questions also arise on if rejecting the traditional process models can eliminate coordination and coherence in software work

Waterfall Model

• Waterfall model is the most basic model where the project goes through phases of communication, planning, modeling, construction and deployment in a linear fashion

V-Model

• V-Model is an extension of the waterfall model, where each development stage has a testing stage

Problems with Waterfall Model

• Real projects rarely follow a sequential flow that the model proposes
• It's difficult for the customer to state all requirements explicitly, and accommodate uncertainty
• It is hard to detect errors causing issues until late in the project

Incremental Model

• Incremental model consists of multiple waterfall cycles, where each cycle delivers an increment in capability

Evolutionary Models: Prototyping

• Prototyping involves the stages quick plan, modeling quick design, construction of prototype, deployment delivery & feedback and communication
• In this model each stage of development leads to the next

Evolutionary Models: The Spiral

• The spiral model involves planning (estimation, scheduling, risk analysis), communication, modeling (analysis, design), deployment (delivery, feedback) and construction (code, test)
• In this model risk assessment helps in each stage

Evolutionary Models: Concurrent

• Concurrent model involves stages of none, under development, awaiting changes, under review, under revision, baselined and done
• This model represents the state of a software engineering activity or task

Other Process Models

• Component based development is the application of development when reuse is a development objective
• Formal methods emphasize the mathematical specification of requirements
• AOSD (Aspect-Oriented Software Development) provides a process/methodological approach for aspects
• Unified Process comprises a use-case driven, architecture-centric, iterative and incremental model

Unified Process (UP) Phases

• Inception encompasses customer communication and planning
• Elaboration encompasses communication and modeling
• Construction is identical to the construction activity for generic software processes
• Transition encompasses later stages of construction and the initial part of deployment (delivery, feedback)
• Production coincides with deployment

UP Work Products

• In all the work products are vision document, initial use case model, business model, analytical model, design model, test and design components

Personal Software Process (PSP)

• Planning activity isolates requirements and develops size/resource estimates
• High-level design develops specifications or each component, and prototypes
• High-level design review implements methods to uncover errors with metrics maintained
• Development code is reviewed, compiled, and tested with metrics maintained
• Postmortem will analyze the effectiveness of processes

Team Software Process (TSP)

• TSP builds self-directed teams that plan and track work, establishes goals, and owns plans
• TSP shows managers how to coach and motivate their teams to help sustain performance
• TSP accelerates software process improvement by making CMM Level 5 behavior standard
• CMM (the Capability Maturity Model measures the effectiveness of a software process
• TSP provides guidance to high-maturity organizations and support uni teaching of industrial-grade team skills

TSP Framework Activities

• TSP framework involve these stages project launch, high-level design, implementation, integration and test and postmortem

Explore software process models, including linear, iterative, evolutionary, and parallel flows. Understand the framework activities, actions, and tasks involved in software engineering. Learn about task sets and umbrella activities that support the process.