Upload
teresa-carter
View
226
Download
0
Embed Size (px)
DESCRIPTION
System analysis approaches There are 4 system analysis approaches; Model driven analysis approach Accelerated analysis approach Requirements discovery methods Business process redesign methods
Citation preview
ANALYSIS PHASE OF BUSINESS SYSTEM DEVELOPMENT METHODOLOGY
INTRODUCTIONSystem Analysis – is a term that describes
the early phases of systems development.problem solving technique that decomposes a
system into its component pieces for the purpose of studying how well those component parts work & interact to accomplish their purposes.
System analysis approachesThere are 4 system analysis approaches;
Model driven analysis approachAccelerated analysis approachRequirements discovery methodsBusiness process redesign methods
Model Driven Analysis ApproachesEmphasizes the drawing of pictorial system models
to document & validate both existing & proposed system.
The system model becomes the blueprint for designing & constructing an improved system.
Example of software : VISIO
Structures AnalysisWas one of the first formal approach for system
analysis of business information system.Used to either analyze an existing system, define
business requirements for new system or both.
Model Driven Analysis ApproachesInformation EngineeringModel driven & data centered approach to plan,
analyze & design information systems.Consists of pictures that illustrate &
synchronize the system’s data & processes.Said to be data-centered paradigm because it
emphasizes the study & requirement analysis of data requirements before those of the process & interface requirements.This is based on the belief that data is a corporate
resources that should be planned & managed.
Model Driven Analysis ApproachesObject Oriented AnalysisIs a technique that integrates data & process
concerns into constructs called objects.Consists of pictures that illustrates the
system’s objects from various perspectives such as structure & behaviour.
Unified Modeling Language (UML) provides a graphical syntax for an entire series of object models.
Accelerated Analysis ApproachesEmphasize the construction of prototypes by
rapidly identifying business & user requirements for a new system.
Emphasizes the interface building blocks in the information system framework by constructing sample forms & reports.
Prototype – a small scale, incomplete but working sample of desired system.
Accelerated Analysis ApproachesDiscovery PrototypingUses rapid development technology to help users
discover their business requirements by having them reach to quick-and- dirty implementation of those requirements.
Rapid Architecture AnalysisAn accelerated analysis approach that also builds
a system models.Attempts to derive system models from existing
systems or discovery prototype.It is made possible by reverse engineering
technology that is included in many tools such as CASE & programming languages.
Accelerated Analysis ApproachesReverse engineering technology reads the
program code for an existing database, application program, user interface & automatically generates the equivalent system model.
The resulting system model can be further edited by system analyst & users to provide a blueprint for a new & improved system.
Requirement Discovery MethodsIncludes those techniques to be used by system
analyst to identify or extract system problems & solution requirements from the user community.
Fact-finding TechniquesAn essential skill for all system analysts.Classical set of techniques used to collect
information about system problems, opportunities, solution requirements & priorities.
Accelerated Analysis Approaches
Fact finding techniques;Sampling of existing documentation, reports,
forms, memosResearch of relevant literature, site visitsObservation on the current system & work
environmentQuestionnaires & surveys of the management &
usersInterviews of the appropriate managers, users &
technical staffs.
Business Process Redesign Methods
Business process redesign – the application of system analysis methods to the goal of dramatically changing & improving the fundamental business processes of an organization, independent of information technology.
Suitable for a study of existing business processes to identify problems & inefficiencies that is addressed in requirements for new / improved system.
The Preliminary Investigation PhaseInvestigation is done by system analyst to
study the systems request & recommend specific action.
The analyst gathers fact about the problem / opportunity, project scope & constraints, project benefits & estimated development time & cost.
The end product of the investigation is a report to the management.
Steps in the Preliminary Investigation
Step 1:Understand the problem /
opportunityStep 2:
Define project scope & constraints
Step 3:Performs fact-finding
Step 4:Determine feasibility
Step 5:Estimate development time & cost
Step 6:Present result/recommendation to
management
Steps in the Preliminary Investigation
Step 1: Understand the problem / opportunitySystem analyst might need to develop a business
profile.Analyst will need to understand & know how the
modifications will affect the business operation or system even when it’s a small alteration.
Step 2: Define the project scope & constraintsMeans to define boundaries/extent of the project
being as specific as possible.Projects that expands gradually without specific
authorization is called = project creep
Steps in the Preliminary Investigation
Types of constraints ; present, future, internal, external, mandatory & desirable.
Step3: Perform fact-findingAnalyst will perform this step using various techniques
such as; Analyze organization charts – to understand how departments
functions & identify the individual involved Conduct interview – interviewing the identified individual. Review current documentation – analyst should check whether
the documentation received is accurate & complete Observe operation – use statistic technique to check the
frequency Carry out a user survey – especially when it involves larger
group.
Steps in the Preliminary Investigation
Step4 : Determine feasibilityTo determine economic feasibility.
Step5 : Estimate time & costTo determine cost & time the following need to
be addressed: What information needed & how to gather & analyze? Source of information to use & the constraints to use it? How many will be interviewed & how much time & cost
for it. How much cost to alayze the information gathered &
prepare final report.
Steps in the Preliminary InvestigationStep6 : present results &
recommendations to managementIf minor problem then recommendation is
given without further analysis, but if the problem is big then further analysis is needed (development phase)
Problem Analysis PhaseProvides the analyst a better understanding
of the problems, opportunities & directives that triggered the project.
The goal of this phase is to study & understand the problem domain well enough to analyze its problems, opportunities & constraints.
Steps in Problem Analysis PhaseAnalyst must follow a series of steps:
Step 1 – study the problem domainStep2 – analyze problems & opportunitiesStep3 – analyze business processStep4 – establish system improvement
objectivesStep 5- update the project planStep 6 – present findings & recommendations
to management
Steps in Problem Analysis PhaseStep 1 – study the problem domain
Attempts to learn about the current system
Step2 – analyze problems & opportunitiesTo perform this step, project team must work
with system owners & system usersCause & effect analysis is a technique in which
problems are studied to determine their causes & effects.
Steps in Problem Analysis Phase
Step3 – analyze business processAnalyze business needs – to clearly define the
business & system requirements.Define business solution – IT experts define in the
form of programs 7 databases, business people define in procedures to fulfill business mission.
Test business solution – evaluating whether the solution fulfills the business need.
Step4 – establish system improvement objectivesAny improvement to the system will be measured
& constraints identified. Criteria for success measured in term of objectives
Steps in Problem Analysis Phase
Step 5 – update the project planThis task is triggered by completion of the system
improvement objectives.Initial project plan = input, updated project plan
= output
Step 6 – present findings / recommendationsThis task is triggered by the completion of the
updated project plan.
Requirements Analysis PhaseDefines the business requirements for a new
system.Final deliverables & milestones is to produce
a business requirements statement that will fulfill the system improvement objectives.
Steps in Requirements Analysis PhaseSteps are as follows:
Step 1 – define requirementsStep2 – analyze functional requirementsStep3 – trace & complete requirementsStep4 – prioritize requirementsStep5 – update the project planStep6 – outgoing requirement management
Steps in Requirements Analysis Phase
Step1 : define requirementsA functional requirement – a description of activities &
services a system must provide (input, output, stored data & processes)
Non functional requirement – description of other features, characteristics & constraints that define a satisfactory system (performance, budgets, cost)
Step2 : Analyze functional requirementsSystem modeling – graphical representation of
concept or process that system developers can analyze, test & modify
Prototyping – creation of early working version of the information system or its components.
Steps in Requirements Analysis PhaseStep3 – Trace & complete requirements
Tracing each system model / prototype back to the functional requirement to ensure all functional requirements are fulfilled.
Step4 – prioritize requirementsTimeboxing – technique that delivers
information system’s functionality & requirements through versioning.
Steps in Requirements Analysis PhaseStep5 : update the project plan
The completed business requirements statement completes the task, as well as the requirement analysis phase.
Step6 : ongoing requirement managementRequirement management defines a process
for everyone involved in the system development that specifies how changes are to be requested & documented, how to be logged & tracked, etc
Decision Analysis PhaseIdentifies candidate solutions, analyses those
candidate solutions & recommends a target system that will be designed, constructed & implemented.
Steps in Decision Analysis PhaseSteps are as follows ;
Step1 – identify candidate solutionsStep2 – analyze candidate solutionsStep3 – compare candidate solutionsStep4 – update the project planStep5 – recommend a system solution
Steps in Decision Analysis Phase
Step 1: identify candidate solutionSystem owners & users may not be directly involved in
the task, but they may contribute ideas & opinions that start the task.
Step2: analyze candidate solutionEach candidate solution must be analyzed for
feasibility.4 criteria:
Technical feasibility Operational feasibility Economic feasibility Schedule feasibility
Steps in Decision Analysis PhaseStep3 : Compare candidate solution
The deliverables of this task is the solutions to be recommended. If more than one solution is recommended, priorities should be established.
Step4 : update the project planSystem analyst are adjusting scope
accordingly, so based on the solution recommended, analyst should re-evaluate project scope & update project plan accordingly
Steps in Decision Analysis PhaseStep6 : Recommend a solution
This task is triggered by the completion of the updated project plan.