meljun cortes analysis modeling------> tools for thesis writing in bsit/bscs

7/27/2019 MELJUN CORTES Analysis Modeling------> Tools for thesis writing in BSIT/BSCS

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Analysis ModelingChapter 12DFD , ERDTopics

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Who does AnalysisModeling?

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Why Analysis Modeling?

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Analysis ModelAnalysis Modeling

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Analysis Model

Structure of Analysis Model

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Analysis Model

The analysis model must achieve three primaryobjectives

to describe what the customer requires,

to establish a basis for the creation of a softwaredesign, and

to define a set of requirements that can be validatedonce the software is built.

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Data ModelingAnalysis Modeling

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Data Modeling

Data modeling answers a set of specific questionsthat are relevant to any data processingapplication. What are the primary data objects to be processed by

the system? What is the composition of each data object and what

attributes describe the object? Where do the objects currently reside? What are the relationships between each object and

other objects? What are the relationships between the objects and the

processes that transform them?

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Data Objects, Attributes,And RelationshipsData Modeling

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Data Objects, Attributes, AndRelationships Data Objects

A data object is a representation of almost any

composite information that must be understood bysoftware.

A data object can be an external entity, a thing, anoccurrence or event, a role, an organizational unit, aplace, or a structure.

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Data ObjectsData Objects

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Data Objects, Attributes, AndRelationships Attributes

Attributes define the properties of a data object andtake on one of three different characteristics. They canbe used to

name an instance of the data object,

describe the instance, or

make reference to another instance.

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AttributesAttributes

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Data Objects, Attributes, AndRelationships Relationships

Data objects are connected to one another in

different ways.

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RelationshipsRelationships

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Entity Relationship DiagramData Modeling

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Entity Relationship Diagram

Entity Relationship Diagram is therepresentation of data objects between theirrelationships.

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Entity RelationshipDiagram

Expanded ERD

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Functional ModelingAnalysis Modeling

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Functional Modeling

Information is transformed as it flows througha computer-based system. The system acceptsinput in a variety of forms; applies hardware,

software, and human elements to transform it;and produces output in a variety of forms.

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Functional ModelingInformation flow model

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Data Flow DiagramsFunctional Modeling

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Data Flow Diagrams

As information moves through software, it ismodified by a series of transformations.

A data flow diagramisagraphicalrepresentation that depicts information flowand the transforms that are applied as data

move from input to output.

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Data Flow Diagram

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Extensions for Real-TimeSystemsFunctional Modeling

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Extensions for Real-Time Systems

Many software applications are timedependent and process as much or morecontrol-oriented information as data.

A real-time system must interact with the realworld in a time frame dictated by the realworld. Aircraft avionics, manufacturing process

control, consumer products, and industrialinstrumentation are but a few of hundreds ofreal-time software applications.

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Behavioral ModelingAnalysis Modeling

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Behavioral Modeling

Behavioral modeling is an operational principlefor all requirements analysis methods.

It also reproduces the required behavior of theoriginal analyzed system, such as there is aone-to-one correspondence between the

behavior of the original system and thesimulated system

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Behavioral Modeling

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Structured AnalysisMechanicsAnalysis Modeling

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Entity Relationship DiagramStructured Analysis Mechanics

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1. During requirements elicitation, customersare asked to list the things that the

application or business process addresses.

These things evolve into a list of input andoutput data objects as well as external entitiesthat produce or consume information.

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2. Taking the objects one at a time, the analystand customer define whether or not aconnection (unnamed at this stage) exists

between the data object and other objects.

3. Wherever a connection exists, the analyst and

the customer create one or moreobject/relationship pairs.

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4. For each object/relationship pair, cardinalityand modality are explored.

5. Steps 2 through 4 are continued iterativelyuntil all object/relationships have beendefined. It is common to discover omissions

as this process continues. New objects andrelationships will invariably be added as thenumber of iterations grows.

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6. The attributes of each entity are defined.

7. An entity relationship diagram is formalized

and reviewed.

8. Steps 1 through 7 are repeated until data

modeling is complete.

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Entity Relationship Diagram Connections

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Entity Relationship Diagram Developing Relationships

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Data Flow ModelStructured Analysis Mechanics

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Data Flow Model

The level 0 data flow diagram should depictthe software/system as a single bubble;

Primary input and output should be carefullynoted;

Refinement should begin by isolatingcandidate processes, data objects, and stores tobe represented at the next level;

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Data Flow Model

All arrows and bubbles should be labeled withmeaningful names;

Information flow continuity must bemaintained from level to level, and

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Data Flow Model

One bubble at a time should be refined. Thereis a natural tendency to overcomplicate thedata flow diagram. This occurs when the

analyst attempts to show too much detail tooearly or represents procedural aspects of thesoftware in lieu of information flow.

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Data Flow ModelLevel 0

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Grammatical ParseStructured Analysis Mechanics

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Data Flow ModelLevel 2Monitor Sensors

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Control Flow ModelStructured Analysis Mechanics

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Control Flow Model

List all sensors that are "read" by the software.

List all interrupt conditions.

List all "switches" that are actuated by anoperator.

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Control Flow Model

List all data conditions.

Recalling the noun/verb parse that was

applied to the processing narrative, review all"control items" as possible CSPECinputs/outputs.

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Control Flow Model

Describe the behavior of a system byidentifying its states; identify how each state isreached; and define the transitions between

states.

Focus on possible omissions

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Control SpecificationStructured Analysis Mechanics

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Control Specification

The control specification (CSPEC) representsthe behavior of the system in two differentways.

The CSPEC contains a state transitiondiagram that is a sequential specification of

behavior. It can also contain a programactivation tablea combinatorial specificationof behavior.

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Data DictionaryAnalysis Modeling

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Data Dictionary

The data dictionary is an organized listing ofall data elements that are pertinent to thesystem, with precise, rigorous definitions so

that both user and system analyst will have acommon understanding of inputs, outputs,components of stores and [even] intermediatecalculations.

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Data Dictionary

Name

the primary name of the data or control item, the

data store or an external entity.

Alias

other names used for the first entry.

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Data Dictionary

Where-used/how-used

a listing of the processes that use the data or

control item and how it is used.

Content description

a notation for representing content.

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Data Dictionary

Supplementary information

other information about data types, preset values

(if known), restrictions or limitations, and so forth.

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Data Dictionary

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