Summary of letures-8

Nature of good design
Design is process of describing,organizing and structuring system components at architectural design level and detailed design level
*Focussed on construction
*Simmilar to developping blueprints
Design components of new system are
1.Application architecture
2.user interfaces
3.system interfaces
4.database
5.network diagram
6.system control
The main outcome of design will become as diagrams and charts of proposed system

Summary of lectures 7

Finishing Analysis
This part is mainly done by he project manager with the support of developer team and priotize requirments on scope and level of automation.
1. This means the functions new system will support
2. Level of automation means how automated the selected functions will be.
Application developement enviorment
Computer hardware, systems software and networks.
Determine what alternatives are possible fordeveloping solution• Implementation alternatives include:– Building system in-house– Buying packaged or turnkey solution– Contracting with developer to build it (outsource)• Develop recommendations and present tomanagement to make funding decisions.

Summary of lecture - 6

Use Case modeling
What is use case modeling?
This is a graphical model that represents the users with system involvement
Relationships between usecase
Documents situation where one use case requires the services of a common
subroutine
• Another use case is developed for this common subroutine
• A common use case can be reused by multiple use cases
What is Activity diagram?
Diagram showing business process activities.
Ex - UML Diagram, usecase diagram and sequence diagram
SSD lifelines

Vertical line under object or actor:
– Shows passage of time
• If vertical line dashed:
– Creation and destruction of thing is not important for scenario
• Long narrow rectangles:
– Activation lifelines emphasize that object is active only during part of scenario
Domain model class diagram
This provides definition of system components and contains important class information for implementation as well as conceptual data model.
Object-oriented approach has complete set ofdiagrams that together document the user’sneed and define system requirements• Requirements specified using followingmodels:– Domain model class diagrams– Use case diagrams– Use case detailed model, either descriptive format oractivity diagram– System sequence diagrams (SSDs).

Summary of lectures 5

Week 5 - Tradditional or structured approach to Analysis
DFD and levels of abstraction
*these are the diagrams that provide multiple level of detail
*Higher level diagrams provide general view of system
*Low level diagrams peovide detail level of system
*Different views are known as level of abstraction

Context diagrams
This is a DFD that summarizes all the processing activity and shows system boundaries.
*this used OOA also

INFORMATION ENGINEERING MODELS
This mainly focuses on Enterprise size, data requirments and Strategic planning
This shares features with structured system developement

Mainly DFD's are easy to read and can show all the key features of system
Analyst may define processes as structured English process specification, decision table, decision tree, or process decomposition DFD
Models from IE may supplement DFDs– Process decomposition diagram (how processes onmultiple DFD levels are related)– Process dependency diagram (emphasizesinteraction with stored entities)– Location diagram (geographic where system used)– Activity-location matrix (which processes areimplemented at which locations)– Activity-data (or CRUD) matrix (where data used).
End of lecture

System Analysis lecture 4

This week mainly covers the Analysis part
During the Analysis part there are few steps the Analyst should follow, the main thing is modelling

Reason for modeling
Learning from modeling process
Reducing complexity of abstaction
communicating with other members
documenting for future maintenence

Types of Models
Mathermatical
Descriptive
Graphical
Defining system requirments
Logical model - provide detail without regard to specific technology
Design phase
physical model
extend logical models

Events related to system requirments
Events occures at specific time and place
trigger - this means the system process

Requirment definition
This determines relevant events
common events are external events, temporal events and state events

Identifying events can be difficult to determine but these are very useful for trace a transaction's lifecycle.
Charactoristics of entities
1.Relationship
2.Attribute
Data entities
*Things system needs to store data about in traditional IS approach.
*This used to create the database design model for relational database

Objects

• Objects does the task and stores information within the system
• Objects also have behaviours and attributes

1.Class-type of thing

2.Object-Each specific thing

3.Methods-Behaviours of objects of the class

The class diagram

the main types are generalization- general superclass to specialized subclass

Aggregation-this relates to objects and its parts.

UML and its purposes

this presents object management

1.The purpose is promote theory and practice of object technology for developement of distributed systems

2.Provide common architectural framework.

The requirments of object oriented approach

• system requirments are specified and documented through process of building models
• Events are the new business processes that new system must perform
• Things are problem domain objects.

Object oriented models

• Class diagram
• usecase diagram
• system sequence diagrams
• state chart diagrams
• activity diagrams

System Analysis lecture 3

This lecture covers the requirments gathering for the system developement
In this stage Analyst will study about the organization structure, business process and information flow. this stage called as fact finding also. The Analyst will conduct interviews with each level of people and he will gather information and he will come to know the information flow and communication of Information. This stage conatins 2 defining ways
1.Logical modeling

2.Physical modeling

Primary information gatherring techniques
build prototype working models.

Prototype working models
Conduct JAD sessions
research vendor solutions
observe and document business processes
Once the Analyst models each and every process, he will note down the functions what the new system should according to the procedures and business functions. In this stage Analyst shoud consider about the security measures also. People who are in new system

1.Users

2.Clients

3.Technical staff (Analyst will conduct interview wil each and every group of person) There are some techniques that Analyst follows while gathering requirments

1.Structural Approach - create model of existing system and gathers information of existing system
2.Current Approach - Identifying logical requirements and balancing the new system requirements This stage includes fact finding way also which means reviewing the old system reports, invoices, information flows, and forms etc and then the Analyst will gather how the information flows at current situation and he will know about the current rules and redundancies and understands the process. Another stage of requirment gathering is preparing checklist, this contents the current system functions and the the new system functions. and the additional things that new system should do. In this stage, the Analyst will conductt interviews with each people or group of people. This will bbe an expense for the organization, but the Analyst should get the correct information from the users.

System Analysis lecture 2

This lecture mainly contains about the system development lifecycle and system design

The system developement and designing always should be well planned and have strong end point and these gives the organization to get the desired output.

The good analysing and designing gives reliable, robust and efficient system.

The lifecycle of system developement

*Planning - Understanding the problem and ensuring the feasibility and obtaining approval
*Analysing - Gathering the detail from ongoing process and getting the idea for the new system and knowing "What system should do?"
*Design - After analysing, getting an image of the organization structure and gathering the requirements.
*Implementation - In this stage all the program developement will be done ex - coding, testing, programming. and user training.
*Support/maintenence - After the Implementation of system, this stage will continues forever and this stage includes problem solving, system running and System maintenence.

The main models in system developement are

Flowchart, data flow diagram, Entity relationship diagram, usecase diagram and sequence diagram.

The main tools they used system developement
Project management application
Drawing tools
Computer aided software etc

There are two different approaches in system designing
1.Traditional approach
2.Structured Programming

System Analysis lecture 1

This lecture covers the Introduction of system analysing and designing

Systen analysis is very crucial to succeed in modern business, so the Analyst should have an overall knowledge of the organization structure, functions, functional workflow and their management techniques. The information system is a collection of many interelated components.

The System Analysis helps to

* Make the workflow effiency

*Helps to make business more competitive

System Analyst should consider in two areas

Which are system analysis and system design

System analysis means "What system should do"

System design means "How the system can be implemented physically" and this helps to solve business problems with it.

Analyst is a person who expertizes in more than one area. ex - programming, designing, networking, managerial, and technical areas and they mainly involves in special tasks such as business process reengineering.(These used to do radical improvement to system)