Software Engineering: A Practitioner’s Approach, 6/e Chapter 3 Prescriptive Process Models

SW Process Models It is a set of activities required to: Prescriptive process models advocate an orderly approach to software engineering. It is a set of activities required to: Define, design, implement, test and maintain a software product. A SW process model is chosen based on the nature of the project.

SW Process Model Phases All models have phases and each phase has 3 components: Set of activities, this is what you do. Set of deliverables, this is what you produce. Quality control measures, this is what you use to evaluate the deliverables. The activities defines the process Framework, the generic set encompasses: Communication, planning, modeling, construction, and deployment

The Waterfall Model This Model suggests a systematic, sequential approach to SW development that begins at the system level and progresses through analysis, design, code and testing.

Waterfall Model Advantages Disadvantages Easy Structured Provide a template into which methods for analysis, design, code, testing and maintenance can be placed. Disadvantages Sequential, does not reflect reality Does not allow for feedback Does not produce a prototype User must wait until the end to see the final program.

When to use the Waterfall Model Simple Projects Limited amount of time Requirements are well understood We can use it for our Class Project.

Incremental Models Goal to provide quick basic functionality to the users Process is not linear Requirements are well defined Software is completed in an increments fashion Will Study 2 models: Incremental Model RAD

Incremental Model It combines characteristics of the waterfall model and the iterative nature of the prototyping model. 1st build is usually the CORE product Each increment “deliverable” may add a new functionality. This is repeated until the product is complete

The Incremental Model Communication Planning Modeling Construction Deployment

When to Use the Incremental Model When staffing is not available by deadline. When the software can be broken into increments and each increment represent a solution

The Rapid Application Development RAD Model Builds on the Incremental model with emphases on short development cycle. In other words high speed waterfall model Components are build using this model as a fully functional units in a relatively short time It assumes that the system can be modularized RAD will fail if you don’t have strong and skillful teams High performance might be an issue

The RAD Model

Evolutionary Process Models Core requirements are well understood but additional requirements are evolving and changing fast Time-to-Market Iterative – software gets more complex with each iteration Prototype Spiral Concurrent

Evolutionary SW Process Models Advantages Do not require full knowledge of the requirements Iterative Divide project into builds Allows feedback, show user something sooner Develop more complex systems

Prototyping Model Start with what is known about requirements. Do a quick design. Build the prototype by focusing on what will be seen by the user. Use the prototype to show the user and help refining requirements.

Evolutionary Models: Prototyping Quick plan communication Modeling Quick design Deployment delivery & feedback Construction of prototype

When to Use Prototype Model When the customer define general objectives for the SW but does NOT identify details about INPUT, OUTPUT, or processing requirements. The developer is unsure of the efficiency of an algorithm, human machine interaction, etc.

Prototype Model Advantages Prototype is served as the machinery for identifying requirements. Is developed very quick. Disadvantages Customer might think that the prototype is the final product and forget lack of quality i.e PERFORMANCE, RELIABILITY.

Spiral Model Iterative (like Prototype) and controlled (like waterfall) model. Software is developed using evolutionary releases Software complexity increase with each release

Spiral Model Consist of 6 task regions. Customer communication - the goal is to establish good communication between customer and developer. Planning - produce/adjust project plan. Risk analysis - assess management and technical risks. Engineering - build one or more representations of the application. Construction and release - - to construct, test, install and support the application. Customer evaluation – get customer feedback.

Evolutionary Models: The Spiral

When to Use the Spiral Model Very large projects. When technical skills must be evaluated at each step.

Component based development The process to apply when reuse is a development objective Evolutionary COTS are used to build software Steps: Identify candidate components Design each using and model or OO classes Component integration Architecture Testing

CBD component-based development (CBD) model incorporates many of the iterative characteristics of the spiral model. The main difference is that in CBD the emphasis is on composing solutions from prepackaged software components or classes

Process Models AOSD—provides a process and methodological approach for defining, specifying, designing, and constructing aspects

Unified Process a “use-case driven, architecture-centric, iterative and incremental” software process closely aligned with the Unified Modeling Language (UML) Tools are used to describe customer views (use cases) Used mainly for OO based methodologies Runs in phases

The Unified Process (UP) inception Phase 1 Communication + Planning Phase 2 Planning + Modeling elaboration inception Phase 3 Coding, unit test & integrate Components result Phase 4 Deployment

UP Phases

UP Work Products

BackUp

Project Day Care Center

Child Care Center for NCC Your company has been awarded a contract to develop Child Care Software for Neñios Care Center (NCC).  The software should maintain a database of Family, Child, and Payroll information.  Users of the software shall have the ability to add/update/delete all information based on their access levels.  All employees (teachers, admin staff, etc.) will be identified by a unique login ID and given a default password. The employee first and last name should be stored

Child Care Center for NCC The general requirements for the software are as follows: Any change in the database (add or update) the user ID and time of change should be stored on the record. The system must respond to all requests within 20 seconds. A web-based solution is optional. The ability for an employee to update the password is optional. The software shall support the ability to store, update, maintain, and delete of Family & Child Information, Family and Child Billing, and Payroll information as specified in Amendment A.

Family and Child Information Store and track child, parent and family information Data including but not limited to: Parent names, addresses, phone numbers, email addresses, emergency contacts, authorized pick ups, etc. Child Name, Birth Date, Class, Special Needs, Photo, etc. Immunization tracking information: recording immunization types, physicals and dates Classroom Tracking & Scheduling Classrooms, programs, activities, schedules, etc Immunization Software, Alerts you when an immunization is needed and prints reports showing immunization dates and immunization due notices for parents. Waiting List & Potential Customer Tracking

Family and Child Information cont Daily Reminders, upcoming appointments, contract renewals, etc. Customer Log Notes, Maintain records of correspondence with parents, child's special needs, incident reports, and more. Reports: Call Sheets, Sign In & Out Sheets Customer Directories Daily Classroom & Center Enrollment Reports Birthday Lists & Child Age Reports Parent/Child Cross Reference Reports Family Registration Information Immunization Due & History Reports Child Enrollment/Withdrawal Reporting Child Notes & Comments Reports

Family and Child Billing track each family’s balance including their child care billing history of registration fees, tuition charges, family discounts and payments received Billing History, history of registration fees, tuition charges, family discounts and payments. Late Fees & Balance Due Notices, late payment fees and print balance due notices to all families who are past due. Receipt Printing Reports: Customer Account Balance (Notice) Account Activity Report Billing of tuition based on actual attendance (Attendance Tracking). Overtime and hourly billing for late pick ups and extra hours

Payroll Pay check, Overtime Withholds and tax information Reports Calculates pay period hours, determines gross pay, applies all withholdings, and prints checks Overtime Withholds and tax information such as state, federal,FICA Reports Employee Earnings Withholdings Summary (W2) Total Revenue Reports

Security Login is required for all users Users can be divided into groups and access is granted on a per group basis for example you may want to allow only the managers group to view, update, or delete payroll information)

Backup Sliddes

Evolutionary Models: Concurrent State tracking for each framework activity Defines a network of concurrent activities Actions cause state changes in one or more activities action