LESSON-4 SOFTWARE CONSTRUCTION BY PARTS (Cont’d; Ashraf, Khan, and Mir)
LESSON-4 SOFTWARE CONSTRUCTION BY PARTS (Cont’d; Ashraf, Khan, and Mir)
4. Application Systems Engineering Methodologies
4.1 Need
Acceptance in the MIS environment; for ensuring the end product complies with the standards (quality control).
Automation through the use of CASE tools provides links from requirement definition through to system delivery. It enhances productivity by means of reusability and standards.
Large problem domains and large-scale designs: to ensure consistency and comprehensiveness in the analysis and design phase.
Documentation Requirements: for example, classes, message flow diagram showing how classes collaborate to achieve particular application requirements.
Application Development Methodologies follow a life cycle to manage the development process.
These differ in emphasis placed in each phases and in their discipline and control.
Three of the most common are;
The Waterfall Approach
The Spiral Approach
Incremental Approach
4.2 The Waterfall Approach;
It is characterized by requiring a formal sign off for each phase before work commences on the next phase.
The phases are;
Requirements definition
Analysis
Design
Solution Production
Building and Testing
Production and maintenance
It is adequate when there is a complete understanding of user requirements.
Highly skilled people perform the analysis and design.
In this approach, the user sees the system is in the last stages of development.
If there are changes in the requirements, a major revision would be required in order to accommodate any modifications.
4.3 The Spiral Approach
This based on building several levels of prototypes and performing a risk analysis at each level
The above noted five phases are still followed, but the emphasis placed on each phase differs. The steps are;
a. Planning for the initial or next iteration of the problem solution
b. Determining the objectives, alternatives, and constraints
c. Performing a risk analysis
d. Producing a prototype solution
e. Validating the prototype against the current objectives
f. Performing the whole process again until a product, capable of being
implemented, has been produced.
In contrast with The Waterfall Approach;
Step 1 is analogous to the Requirement phase.
Steps 2 & 3 represent Analysis and Design Phase.
Steps 4 & 5 correspond to Implement/ Produce and Building/ Testing phases.
This approach is dynamic and is good for medium to large projects of application development. It allows;
The problem to be solved is not fully understood in the first go
Changes can be accommodated during the period of development
Solution itself might have an unknown effect on the real-world
Management focus is on quality and function than financial control.
All the versions will go through the phases, such as;
Planning (requirements validation, plan next iteration)
Analysis & Design (Determine Objectives, Evaluate Alternatives, Modify and Resolve Risk)
Produce Prototypes (Develop and Verify, Next-level Product
4.4 The Incremental Approach
It has some similarities with the Waterfall approach, both have the phasing, but in the incremental approach the development phase delivers first a reduced set of functions, which are in turn enhanced in iteration.
In addition there can be iterations between the phases.
This approach delivers limited functions earlier with a corresponding faster return on investment. It does require careful planning and tight management control.
4.5 Summary
The development of an application goes through five process phases; requirements, analysis, design, implementation, testing, and production.
Several process models methodologies that can be used in the application development that include the waterfall, spiral, incremental models.
All the three methodologies support object technology as to rapidly build a model and perform early prototyping allowing the feedback.
Amongst the three, the incremental development, are better for object-oriented application development than the basic waterfall approach.
Click To MAIN PAGE: OBJECT- ORIENTED RELATIONAL MODELLING E-MONOGRAPH, By J. Ashraf, M. Khan, and H. Mir
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- MESSAGE: DEDICATED TO ANONYMOUS COMBATANTS OF KNOWLEDGEمکتب علم الل مہد منل لحد Learning continues from birth to deathFOR PROMOTION OF LEARNEDNESS SHARE WITH FRIENDS ABOUT;
- CAUSE AND EVENTS – SPATIAL And TEMPORAL RESPECTIVELY: https://be4gen.wordpress.com/2012/11/16/cause-and-events-spatial-temporal-respectively/
- WHETHER ‘BRAIN-POWER’ OR ‘HEART-IMPULSE’ PLINTHS ‘HUMAN GEN’? http://sunedu.wordpress.com/2012/09/17/whether-brain-power-or-heart-impulse-plinths-human-gen/
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