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2 MARK QUESTIONS AND ANSWERS

IT 2251- SOFTWARE ENGINEERING AND QUALITY ASSURANCE

ACD YEAR: 2012-2013(EVEN SEM)

UNIT I - SOFTWARE PRODUCT & PROCESS

1. Define software

Software is collection of computer programs and associated documentation that

when executed provide desired features, function, and performance.

2. Define Software Engineering

Software Engineering is the establishment and the use of sound engineering principle

in order to obtain a reliable and efficient software.

OR

Software engineering is a discipline in which theories, methods and tools are applied

to develop professional software product.

OR

Systematic, disciplined, quantifiable approach to the development, operation and

maintenance of software. That is the application of engineering to software.

3. What are the layers present in layered Technology

Tools

Methods

Process

A Quality Focus

4. What are the various categories of software?

System software

Application software

Embedded software

Engineer ing/ Scientific software

Artificial Intelligence software.

5. Define Process framework

It establishes the foundation for a complete s/w process.

It identifies frame work activities.

Process framework encompasses a set of umbrella activities.

Process defines who is doing what, when, and how to reach a certain goals.

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Process: process is defined as a series of activities in which one or more inputs are

used to produce one or more outputs.

12. Define software engineering paradigm.

To solve actual problems in an industry, a software engineer or a team of

engineers must combine a development strategy that includes the process, methods and

tools. This strategy is referred as software engineering paradigm or process model

13. What is the difference between verification and validation?

VerificationValidation

1. Are we building the product right?

2. Verificat ion shows conformance

with specification.

1. Are we building the right product?

2. Validation shows that the program

meets the customers needs.

14. List the common errors in verification process. Incomplete specifications

Misunderstand of customer communication

Deviation from specifications

Violation of programming standards

Errors in data representation

15. Define software life cycle.

Software life cycle is the period of time beginning with a concept for a software

product and ending whenever the software is no longer available for use.

16. Types of lifecycle model.

1. Prescriptive process model2. Water fall model

3. Incremental process Model1. Incremental Model2. RAD Model

4. Evolutionary process Model1. Prototyping model

2. Spiral Model3. The concurrent development Model

5. Specialized Process Model

1. Component based development Model2. Formal Methods Model

3. Aspect oriented S/W development (AOSD)6. Unified process model

17. Define Water fall model. It is an oldest model

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Sometimes called classic lifecycle model

It is a systematic and sequential approach

Start from communication and process through planning, modeling,

construction and deployment.

18. What are the Steps present in Waterfall model?

Communication: Collaboration with customer, gathering information

Planning: establish a work plan, describe technical risks, list resource,

work products etc

Modeling: creation of models, and design

Construction: coed generation and testing

Deployment: delivered to the customer ,evaluate, and provides a feedback

19. Drawbacks of waterfall model

Oldest model. Rarely follows the sequential flow. Difficult to collect requirement explicitly at the beginning.

A working version not available in later releases.

It leads a blocking state.

20. What are the phases encompassed in RAD model?

a. Business modeling

b. Data modeling

c. Process modeling

d. Application generation

e. Testing

21. Write the key challenges facing software engineering.

Heterogenity

Delivery

Trust challenge

22. What is meant by development process?

A software development process is a structure imposed on the development of

software product which include analysis, design, code and Test.

23. Give at least two reasons for why prototyping is problematic.

Prototyping model doesnt consider the overall software quality or long term

maintainability.

Developer uses an inappropriate operating system or programming language in order

to get a prototype working quickly.

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24. What are the advantages of prototyping model?

Prototyping model is used when a customer defines a set of objectives for software

but doesnt identify detailed input, processing and output requirements.

It serves as the mechanism for identifying software requirements.

If the prototype is built the developer attempts to use existing program fragments to

develop a working program.

25. What are the characteristics of software? (Attributes of good software).

Software should deliver the required functionality and should be

Maintainable, dependable, usable, efficient.

26. What is the advantage of incremental model?

Incremental model is useful when staffing is unavailable.

Increments can be planned to manage technical risks.

27. Drawbacks of spiral model

If major risks are not discovered and managed problems will occur.

It demands a direct consideration of technical risks at all stages of project.

28. Identify in which phase of the software life cycle the following documents are

delivered.

a. Architectural design, b. Test plan, c. Cost estimate, d. Source code document.

Architectural design: Design phase

Test plan : Testing phase

Cost estimate: Requirement analysis

Source code: Implementation phase

29. Define system engineering.

Concerned with all aspects of computer based systems development ( Specifying

the system , defining its overall architecture , integrating the different parts to create the

finished system etc. ) . It include hardware, software , process engineering and people.

Software engineering is a part of this process.

30. Various phases of System engg. process

Requirement analysis

System design

Sub_ System development

System Integration

System deployment

System evolution

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System decommissioning.

31. Define System Engg. Hierarchy

System Engg encompasses a collection of top-down and bottom up methods to

navigate the hierarchy.

The levels are

World view

Domain view

Element view

Detailed view

32. Define a system and computer based system.

System is an established way of doing something like method, procedure.

Computer based system is a set of arrangement of elements that are organized to

accomplish some predefined goal by processing information system elements.

33. Define Business Process Engineering (BPE)

The goal of Business Process Engineering (BPE) is to define architectures that

will enable a business to use information effectively. Three different architectures are

Data architecture

Applications architecture

Technology architecture

34. Define Product engg.The goal of product engg is to translate the customers desire for a set of defined

functionalities into a working product. Four components are software , hardware ,data ,

people.

UNIT II SOFTWARE REQUIREMENTS

1. List out the e lements of analysis model.

i. Data Dictionary

ii. Entity Relationship Diagram

iii. Data Flow Diagram

iv. State Transition Diagram

v. Control Specification

vi. Process specification

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2. What are the informations available in the data dictionary?

Precise definition of data elements, User names, roles and privileges, Schema

objects, Integr ity constraints, stored procedure, General data base structure, Space

allocations.

3. What are the various types of traceability in software engineering?

i. Source traceability These are basically the links from requirement to stakeholders

who propose these requirements.

ii. Requirements traceability These are links between dependant requirements.

iii. Design traceability These are links from requirements to design.

4. Why it is difficult to gain a clear understanding of what the customer wants?

Customer requirement is gathered at particular period of time. So the customer is

not able to predict the future which they are going to work. So it is difficult to gain a clearunderstand about what they wants.

5. Create a data dictionary that provides with a precise definition of telephone number

it should indicate where and how this data item is used and any s upplementary

information that is relevant to it.

Data dictionary for telephone number:

Name: Telephone number

Aliases: None

Whos used/How used: assess against setup (output)

Dial phone(input)

Supplementary information

Telephone number:[local no.][long distance number]

Local no: prefix+ access number

Long distance no: 1+area code +local number

Prefix: a 3 digit no. that never starts with 0 or1.

Access no: any 4 no. string

6. What are the various prototyping techniques?

i. Dynamic high level language development.

ii. Database programming.

iii. Component and application assembly.

7. What does DFD level0 represent?

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Level0 DFD is called as fundamental system model or context model. In the

context model the entire software system is represented by a single bubble with input and

output indicated by incoming and outgoing arrows.

8. Write the steps in requirement engineering process .

Feasibility study, Requirement elicitation, Requirement analysis, Requirement

specification, System modeling, Requirement validation and management.

9. Compare evolutionary and throw away prototyping.

10. What is meant by software prototyping?

Software prototyping is defined as a rapid software development for validating the

requirements.

11. What is the advantage of software prototyping?

i. Prototype serves as a basis for deriving system specification.

ii. Design quality can be improved.

iii. System can be maintained easily.

iv. Development efforts may get reduced.

v. System usability can be improved

12. Define requirement engineering process.

Requirement engineering is the process of establishing the services that the customer

requires from the system and the constraints under which it operates and is developed.

13. What are the advantages of evolutionary prototyping?

i. Fast delivery of the working system.

ii. User is involved while developing the system.

ii. More useful system can be delivered.

iv. Specification, design and implementation work in co-ordinate manner

Evolutionary Throw away prototyping

1. The objective of Evolutionary

prototyping is to deliver a working system

to end users.

2. Prototypes usually evolve so quicklythat it is not cost effective to produce a

great deal of system requirements.

The objective Throw away prototyping is

to validate or derive the system

requirement.

It may not be possible to prototype someof the most important parts of the system.

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14. Define cardinality and modality.

Cardinality specifies how the number of occurrences of one object is related to the

number of occurrences of another object.

Modality indicates whether or not a particular data object must participate in the

relationship.

15. What is meant by DFD?

Data Flow Diagram depicts the information flow and the transforms that are applied on

the data as it moves from input to output.

16. What is meant by CFD?

Control Flow Diagram show how events flow among processes. It also shows how

external events activates the processes.

17. What is meant by structural analysis?

The structural analysis is mapping of problem domain to flows and transformations. Thesystem can be modeled using Entity relationship diagram, Data flow diagram and control

flow diagram.

18. What are the non functional requirements for software?

The non functional requirements define system properties and constraints.

Various properties of the system can be Reliability, response time, storage requirements.

Constraints of the system can be Input and output device capability, system

representations.

19. Define Data dictionary.

The data dictionary can be defined as an organized collection of all the data

elements of the system with precise and rigorous definitions so that user and system

analyst will have a common understanding of inputs, outputs, components of stores and

intermediate calculations.

20. What do you mean by rapid prototyping?

Rapid prototyping is a technique in which the initial version of the software

system that demonstrates the concept can be developed rapidly. Dur ing rapid prototyping

the initial prototype is produced and can be refined in later versions.

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UNIT III ANALYSIS, DESIGN CONCEPTS AND PRINCIPLES

1. What is an architectural style?

Architectural style describes system category that encompasses

a set of components that performs a function required by a system.

Set of connectors that enable communication, coordination among components

How components can be integrated to form the system

Semantic models enable a designer to understand the overall properties of a

system.

2. Describe version control in the context of SCM.

Configuration management allows a user to specify alternative configurations of

the software system.

3. What is logarithmic Poisson distribution model?

logarithmic Poisson distribution model is a version of failure model which takes the

form

f(t)=(1/p)ln[I0pt+1]

where f(t)=Number of expected failure at time t.

I0=Initial number of failure intensity.

P=Exponential reduction in failure intensity.

4. What is transform mapping?

The transform mapping is a set of design steps applied on the DFD in order to

map the transformed flow characteristics into specific architectural style.

5. What are the types of coupling?

Data coupling , stamp coupling, control coupling, External coupling, Common

coupling, Content coupling.

6. What are the different types of Cohesion?

*Coincidentally cohes ive * logically cohes ive *Temporal cohesion * Procedural

cohesion * Communicational cohesion

7. Differentiate version control and change control.

Version Control combines procedures and tools to manage different versions of

configuration objects that are created during software process.

Change control is a set of procedures to evaluate the need of change and apply the

changes requested by the user in a controlled manner.

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8. List the principles of a software design.

i. The design process should not suffer from tunnel vision.

ii. The design should be traceable to the analysis model.

iii. The design should exhibit uniformity and integration.

iv. Design is not coding.

v. The design should not reinvent the wheel.

9. What is meant by cohesion? How software should be des igned considering cohesion?

Cohesion is a measure of the relative functional strength of a module. The greater

the cohesion of each module in the system, lower the coupling between the modules. The

internal cohesion of a module is measured in terms of the strength of the hiding of

elements with in the module.

10. What are the various models produced by software design process?

*Data design *Architectural design *Interface design * Component level design.11. What are the quality parameters considered for effective modular design?

Two quality parameters are Coupling and Cohesion.

Coupling is defined as a interdependency between the modules.

Cohesion is defined as a individual strength of a module

12. What are types of architectural styles?

i. Data centered architecture.

ii. Data flow architecture.

iii. Call and return architecture.

iv. Object-oriented architecture.

v. Layered architecture.

13. Define real time system.

Real time system is a software system in which the correct functionalities of the

system are dependent upon results produced by the system and the time at which these

results are produced.

14. Define hard and soft real time system.

A soft real time system is a system whose operation is degraded if results are not

produced according to the specified timing requirements.

A hard real time system is a system whose operation is incorrect if results are not

produced according to the timing specificat ion.

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UNIT IV TESTING

1. Define software Testing.

Testing can be described as a process used for revealing defects in software, and

for establishing that the software has attained a specified degree of quality withrespect

to selected attributes.

2. What are the steps for top down integration?

* Main control module is used as a test driver and stubs are substituted for all

components directly subordinate to the main module.

* Depending on integration approach (Depth or breadth first) subordinate stubs are

replaced one at a time with actual components.

*Tests are conducted as each component is integrated.

*The completion of each set of tests another stub is replaced with real component

*Regression testing may be conducted to ensure that new errors have not been

introduced.

3. What are the steps involved in testing real time system?

*Task testing * Behavioral Testing, *Inter task Testing, *System Testing

4. Assume a program for computing the roots of quadratic equation. List out the test

cases using equivalence partitioning method.

Roots of quadratic equation = -b+ b2-4ac

2a

Roots can be equal, unequal or imaginary. So test cases are selected that all the three

conditions are satisfied.

5. Write short notes on equivalance partitioning.

Equivalance partitioning is a black box testing method that divide the input domain of

a program into classes of data from which test cases can be derived.

6. What is the use of drivers and stubs in testing?

A driver is a main program that accepts test case data, passes such data to the

component and print relevant results.

A stub or dummy subprogram uses the subordinate modules inter face, may do the

minimal data manipulation, prints verification of entry and returns control to the module

undergoing testing.

7. What is the objective of unit testing?

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The objective of unit testing is to test the modules individually in order to detect

defects

8. What is Beta testing?

Alpha testing is a testing in which the version of software is tested by the

customer without the developer being present. This testing is performed at customers site.

9. What is system testing and specify the type.

In system testing, the testing of group of components integrated to create a system or

sub-system is done. These tests are based on system specification.

Types of system testing are Recovery testing, Security testing, Stress testing,

Performance testing

10. What are the objectives of testing?

Testing is a process of executing a program with the intend of finding an error.

A good test case is one that has high probability of finding an undiscovered error. A successful test is one that uncovers as an-yet undiscovered error.

11. What are the principles of testing the software engineer must apply while

performing the software testing?

All tests should be traceable to customer requirements.

Tests should be p lanned long before testing begins.

The Pareto principle can be applied to software testing-80% of all errors

uncovered during testing will likely be traceable to 20% of all program modules.

Testing should begin in the small and progress toward testing in the large.

Exhaustive testing is not possible.

To be most effective, an independent third party should conduct testing.

12. What are the errors uncovered by black box testing?

Incorrect or missing functions

Interface errors

Errors in data structures

Performance errors

Initialization or termination error

13. What are the guidelines for debugging?

a. Debugging occur as a consequence of successful testing

b. Debugging process begins by executing the test cases

c. Test results are assessed and a lack of correspondence between expected and

actual results

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d. The debugging process attempts to match symptom with cause. This enables to

correct the errors.

14. Distinguish black box and white box testing.

15. What is meant by cyclomatic complexity?

Cyclomatic complexity is a software metric that gives the quantitative measure of

logical complexity of the programV(G)=E-N+2

E-Number of flow graph edges

N-Number of flow graph nodes

16. What is stress testing?

Stress testing is a testing for a system which is executed in a manner that demands

resources in abnormal quantity, frequency, volume.

17. Why tests are important with respect to software?

The purpose of software testing is to ensure whether the software functions appear to be

working according to specifications and performance requirements. This helps in

improving the overall quality of the software.

18. What is meant by regression testing?

Regression testing is used to check for defects propagated to other modules by changes

made to existing program. Thus, regression testing is used to reduce the side effects of

the changes.

19. What is alpha testing?

Alpha testing is a testing in which the version of complete software is tested by

the customer under the supervision of developers. This testing is performed at

developer site.

20. What is meant by Boundary value analysis?

Boundary value analysis is a testing techniquein which the elements at the edge of

the domain are selected and tested.

Black box testing white box testing

1. Black box testing is called behavioral

testing

2.It examines a system functionality with

testcase input and output.

1. white box testing is called glass box

testing

2. Here the procedural details, all the

logical paths, all the internal data

structures are closely examined.

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28. Define Test Cases.

A test case in a practica l sense is attest related item which contains the followinginformation.

A set of test inputs. These are data items received from an externalsource by the code under test. The external source can be hardware,

software, or human.

Execution conditions. These are conditions required for running the test,for example, a certain state of a database, or a configuration of ahardware device.

Expected outputs. These are the specified results to be produced by the

code under test.

29. Write short notes on Test,

A Test is a group of related test cases, or a group of related test cases and test

procedure.

UNIT V SOFTWARE QUALITY ASSUSRANCE

1. Define process in the context of software quality. ( U.Q Nov/Dec 2009)

Process, in the software engineering domain, is a set of methods, practices,

Standards, documents, activities, polices, and procedures that software engineers use to

develop and maintain a software system and its associated artifacts, such as project and

test plans, design documents, code, and manuals.

2. Define Software Quality.

Quality relates to the degree to which a system, system component, or process meets

specified requirements.

Quality relates to the degree to which a system, system component, or process

meets Customer or user needs, or expectations.

3. List the Quality Attributes.

Correctness

Reliability

Usability

Integrity

Portability

Maintainability

Interoperability

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4. Define SQA group.

The software quality assurance (SQA) group is a team of people with the

necessary training and skills to ensure that all necessary actions are taken during the

development process so that the resulting software confirms to established technical

requirements.

5. Explain the work of SQA group.

Testers to develop quality related policies and quality assurance plans for each

project.The group is also involved in measurement collection and analysis, record

keeping, and Reporting. The SQA team members participate in reviews and audits,

record and track Problems, and verify that corrections have been made.

6. Define SCM (Software Configuration management).Software Configuration Management is a set of activities carried out for

identifying, organizing and controlling changes throughout the lifecycle of computer

software.

7. What are the SCM activities?

*Object identification

* Change control

* Version control

*Configuration audit

*Status reporting

8. Define basic equation for the effort estimation models

Effort E=V/L

where V=Volume of the program, L=Length of the program

By Halsteads measurement E=1N2log2

22

9. Categorize the project planner estimates in FP based estimation

Inputs, Data files, External interfaces, Critical performance, Code designed for

reuse, Outputs, inquires, back up, recovery, Master files updated on-line, Multiple

installation.

10. What is the purpose of timeline chart?

The purpose of the timeline chart is to emphasize the scope of the individual task.

Hence set of tasks are given as input to the timeline chart

11. How to measure the function point FP?

i. Determine a number of items occurring in the system.

ii.Unadjusted Function count is calculated by UFC=itemi wi

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iii.Function point FP=UFC * TCF where TCF is Technical complexity factor.

TCF=0.65+0.1fi

12. Define information flow metric.

Information flow metric is defined as the product of length, fan-in and fan-out.

Information flow= length *(fan-in * fan-out)2

13. What is EVA?

Earned Value Analysis is a technique of performing quantitative analysis of the

software project. It provides a common value scale for every task of software project. It

acts as a measure for software project progress.

14. Write the advantages of CASE tool.

*Ability of automate manual activities and to improve engineering insight.

*CASE tools help to ensure that quality is designed in before the products are built.

15. What are types of software maintenance? Corrective maintenance: maintenance for correcting the software faults

Adaptive maintenance: maintenance for adapting the change in environment.

Enhancement maintenance: modifying or enhancing the system to meet the new

requirements

Preventive maintenance: changes made to improve future maintainability.

16. List out few product and process metrics.

Process metrics: Lines of code or function points per module and function, defect

reported for major software function, errors found during formal technical review.

Product metrics: Metrics for testing , maintenance ,quality

17. What are the four categories of CASE tool?

*Business process engineering tool,* Project planning tools,*Risk analysis tools

*Requirements tracing tools.

18. What is meant by Scheduling?

Scheduling is an activity that distributes estimated effort across the planned

project duration by allocating effort to specified software engineering tasks.

19. What are the reasons for software change?

*New requirements emerge when the software is used.* Change in business

environment,*Errors needs to be repaired,* New equipment must be

accommodated,* The performance may have to be improved.

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20. What is meant by COCOMO model?

COnstructive COst MOdel is a cost estimation model, which gives the estimate of

number of person per months it will take to develop the software product.

21. What is software cost estimation?

It is the process of predicting the resources required for software development

process.

22. What is meant by direct and indirect metrics?

Direct measures refers to immediately measurable attributes.(eg):lines of code

Indirect measure refers to the aspects that are not immediately measurable. Eg:

Functionality of the program.

23. What are the building blocks of CASE?

CASE has the following components, Environment architecture, Hardware

platform, Operat ing system, Portability services, Integration frame work, and CASE tools24. What is the purpose of Zips law?

The purpose of ZIPS studies was to investigate dependencies between

frequencies of some words in a sample of text.ZIPs law can be used to derive a length of

document(n) for a given number of classes of tokens.

25. What is meant by metrics and measurement?

Metrics is the degree to which a system component or processes possesses a given

attribute. The software metrics relate several measures. Eg: average no. of errors found

per review.

Measurement means deriving a numeric value for an attribute of a software product

or process.

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UNIT I1. Explain the system engineering hierarchy in detail.

System Engineer ing as a consequence of process.

Focus on variety of elements, analyzing, designing & organizing those elements

into a system

System engg Process are:

Requirement gathering &analysis

System design

SubSystem development

System integration

System deployment

System evolution

System decommmisioning

System design:

Organizing requirements

Identification of subsystem

Requirement assignment

Specifying subsystem functionality

Subsystem interfeace defn

System engineering hierarchy diagram

World view WV={D1,D2,,Dn}Domain view Di={E1,E2,,En}Element view Ei={C1,C2,,Ck}Detailed view

System ModelingTo construct a system model the following restraining factors are to be considered:

Assumptions

Simplifications

Limitations

Constraints

Preferences System Simulation

2. Explain software development life cycle models or software process models.

1.Linear Sequential Model or Classic life cycle model or Waterfall modelDiagram for Waterfall model

The model encompasses the following activities:1. System/information engineering and modeling2. Software requirement analysis

3. Design4. Code generation

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5. Testing6. Support

Advantages and disadvantages2. Prototyping Model

The prototype can serve as the first system which is a throw awaysystem.

Diagram for prototyping model

Activities: Listen to customerBuild/Revise Mock-up

Customer test drives Mock-up

3. RAD Model

Rapid Application Development Model is the type of incrementalModel. Diagram

Phases include1. Business modeling2. Data modeling

3. Process modeling

4. Application generation.5. Testing and turnover.4. Incremental Model

It is an evolutionary software process model.

The first increment is a core product.

Combines the elements of the linear sequential model with

iterative nature of prototyping

Diagram for Incremental model

Activities: analysis,design,code,test

Advantages5.Spiral Model

It is an evolutionary software process model. Combines the elements of the linear sequential model with

iterative nature of prototyping

Used for the development of large sca le systems and software.

Spiral model diagram

The task regions are:

Customer communicationPlanningRisk analysis.

Engineering.Construction and release.

Customer evaluation.6.WIN WIN Spiral Model

It is an evolutionary software process model.

Diagram

The model includes 3 process milestones called anchor points:

Life cycle objectives

Life cycle architecture

Initial Operational Capability

7.Object Oriented Model

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Object Oriented Model Process model which define a network of

activities .

Object oriented model diagram.

Phases in object oriented life cycle model.

Requirement phase

Analysis phaseIdentification of classes

Identification of objects Design phase

Designing interfaces between classes

Encapsulation of networkEstablishing inheritance and code reusability

Implementation and component based development

Testing

UNIT II

1. Explain the various prototyping approaches or prototyping models in detail.

i. Evolutionary Prototyping Objective is to deliver a working system to end user

Start with the user requirements which are best understood.

Diagram for Evolutionary prototyping.Advantages

Accelerated de livery of the system

User engagement with the system

Problems

Management problems

Maintenance problems

Contractual problems

ii. Throw-away Prototyping

Objective is to validate or derive the system requirements.

Diagram for Throw away prototyping

Start with those requirements that are not well understood.

Advantages

Problems

It can be undocumented.

Changes made during the software development proceed maydegrade the system structure.

Sometimes organizational quality standard may not be strictlyapplied.2. Explain the various rapid prototyping techniques or methods

Development techniques which emphasize speed of delivery.There are 3 techniques

Dynamic high level language development

Definition : These are programming language which include powerfulruntime management facilities.

Advantage: Increased power, reduced costDisadvantage: needs large run time support

Database Programming

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Definition4GL(Fourth generation language)

Components of 4GL-Diagram

Data base query language

Interface generatorSpreadsheet/Report generator

Component and application assembly

Diagram-Reusable component compositionLevels:

1.application level2.Component level

Application linking

3. Explain functional and non-functional requirements.

Functional requirements

Statements of services the system should provide, how the system should react to

particular inputs and how the system should behave in particular situations.

Non-functional requirements

Constraints on the services or functions offered by the system.Different types of non-functional requirements (Diagram) are

o Product requirements

Usability requirement-Performance, space requirementEfficiency requirement

Reliability requirementPortability requirement

o Organisational requirements

Delivery requirementImplementation requirement

Standars requirement

o External requirementsInteroperability requirement

Ethical requirementLegislative requirement

4. Explain the structure of software requirements document

Requirements document should satisfy six requirements

Specify only external system behavior

Specify constraints on the implementation

Easy to change

Serve as a reference tool for system maintainers

Record forethought about the life cycle of the system.

Characterise acceptable responses to undesired events.Structure of a requirements documents:

Preface

Introduction

Glossary

User requirements definition

System Architecture

System Requirements Specification

System models

System evolution

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Appendices

Index

5. Explain in detail about data modeling

Data modeling makes use of the Entity Relationship Diagram.

Data Objects, Attributes and Relationships

Data object representation of something that has a number of different

properties or attributes,ExampleAttributes - name a data object, describe its characteristics, make reference to

another object.Relationships Indicate the manner in which data objects are connected to

one another. Example diagram

Cardinality and Modality

Cardinality is the specification of the number of occurrences of one objectthat can be related to the number of occurrences of another object.

o One-to-one cardinality.o One-to-many cardinality.o Many-to-Many cardinality.

Modality of a relation is 0 if there is no explicit relationship or relation isoptional.Modality is 1 if an occurrence of relationship is mandatory.

Entity/Relationship DiagramsComponents of ER Diagram

ER diagram for manufacturer and relationship

6. Explain the requirements engineering tasks in detail.

Requirement engineering process diagram

Four Requirement engineering activities

Feasibility studies

Requirements elicitation and analysis

The activities involved in elicitation and analysis process are:1. Domain Understanding

2. Requirements Collection3. Classification4. Conflict resolution

5. Prioritisation6. Requirements checking

1. Viewpoint oriented elicitationA viewpoint is

1. data source or sink

2. A representation frame work

3. A receiver of servicesPrincipal stages of Viewpoint oriented Requirement method are:

1.Viewpoint identification2.Viewpoint structuring

3.Viewpoint documentation4.Viewpoint system mapping

2. Scenar ioso Event scenarioso Use cases

3.Ethnography

Requirements Validation

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Different types of checks carried out on the requirement duringvalidation are:

Validity checks

Consistency

Completeness

Realism checks

Verifiability

Requirement validation techniques are: Requirement review

Reviewers check for :

o Verifiabilityo Comprehensibility

o Traceabilityo Adaptability

Prototyping

Test case generation

Automated consistency analysis

Requirements Management

1. Enduring and Volatile requirements Enduring requirements

Stable requirements related directly to the domain of the

system. Volatile requirements

Changes during system development or after the systemhave been put into operation.

2. Requirements Management Planning During requirement management stage decide on

Requirements identification

A change management process

Traceability policies

CASE tool support

There are three types of traceability information

Source traceability information

Requirements traceability information

Design traceability information

Requirements management tools is required for:

Requirements Storage

Change Management

Traceability Management

3. Requirements Change Management There are 3 principal stages to a change management process:

Problem analysis and change specification

Change analysis and costing

Change implementation

7. Explain in detail about Functional Modeling.

This model describes the computations that take place within a system.

This model is useful when the transformation from the inputs to outputs iscomplex.

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The functional model of a system can be represented by a data Flow

Diagram (DFD).Data Flow Diagrams/Data Flow Graph/Bubble chartA DFD is a graphical representation that depicts the information flow and the

transforms that are applied as the data move from input to output.Level 0 DFD also called as fundamental system model or context model

represents the entire software as a s ingle bubble with input and output indicated by

incoming and outgoing arrows.Level 1 DFD contains 5 or 6 bubbles. Each bubbles can be refined at Layers to

depict more details.Extensions to Real Time Systems

Ward and Meller extensionsData and control flow using ward and mellor extensions-d iagram

Hatley and Pirbhai extension.

Relationship between data and control models

UNIT III

1. Explain the design steps for transform mapping. Review the fundamental system model.

Level0 DFD for safe home-DiagramLevel1 DFD for safe home-Diagram

Review and refine the data flow diagrams for the software.Level2 DFD for safe home-Diagram

Determine whether the DFD has the transform or transaction flowCharacteristics

Level3 DFD for monitor sensors with flow boundaries-diagram

Isolate the transform center by specifying incoming and outgoing flowboundaries.

Perform first- level factoring.first- level factor ing-Diagram

Perform second-level factoring.Second- level factoring-Diagram

First iteration structure for monitor sesors

Refine the first iteration architecture using design heuristics for

improved software quality2. Explain the design steps in transaction mapping.

Review the fundamental model.

Review and refine the data flow diagrams for the software.

Determine whether the DFD has the transform or transaction flowCharacteristics

Level 2 DFD for user interaction subsystem with flow boundaries-Diagram

Identify transaction center and the flow characteristics along each of theaction paths.

Map the DFD in a program structure amenab le to transaction processing.

Factor and refine the transaction structure and the structure of each

action path.Diagram for first level factoring of user interaction system.

Refine the first iteration architecture using design heuristics forimproved software quality.

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Diagram for first iteration structure of user interaction system.

3. Explain in detail the design concepts.

Abstraction

Functional or Procedural abstraction Data abstraction

Control abstraction

Refinement Modularity

5 criteria to define a effective modular system Modular decomposability

Modular composability Modular Understandability

Modular Continuity Modular protection

Software Architecture

Control Hierarchy

Structural Partitioning

Horizontal partitioning Vertical partitioning

Data Structure

Software Procedure

Information Hiding

4. Explain the different architectural styles for software design in detail.

Data-centered architecture

Data-flow architecture

Call and return architectureso Main program/subprogram architectureso Remote procedure call architectures

Object oriented architectures

Layered architectures

5. Explain real time system?

Real time system is a software system where the correct functioning of the

system depends on the results produced by the system and the time at whichthese results are produced.

Types

Hard real time systemSoft real time system

Real time system modeling

Real time programming

6. Explain the design principles.

The design process should not suffer from tunnel vision.

The design should be traceable to the analysis model.

Design should not reinvent the wheel.

The design should minimize the intellectual distance between the software and

problem as it exists in the real world.

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The design should be structured to degrade gently, even when aberrant data,

events or operating conditions are encountered.

Design is not coding, coding is not design.

The design should be assessed for quality as it is being created, not after

the fact.

The design should be reviewed to minimize conceptual (semantic) errors

7. Explain User interface design process Diagram

Framework activities for User interface design process

1.User,task,environment analysis and modeling2.Interface design

3.Interface construction4.Interface validation

UNIT IV

1. Explain Black Box testing and white box-testing.

White box testing also called as Basis path testing Flow Graph Notation

Cyclomatic Complexity

Deriving Test cases

o Using the design or code as a foundation draw a corresponding flowgraph

o Determine the cyclomatic complexity of the resultant flow graph

Determine a basis set of linearly independent paths

Prepare test cases that will force execution of each path in the basis set

Graph Matrices

Black Box testing also called as behavioral testing

Graph-Based Testing Methods

Equivalence partitioning

Boundary Value Analysis

Comparison Testing

Orthogonal Array Testing

2. Explain about the software testing strategies.

Verification and Validation. Verification refers to the set of activities that ensure

that software correctly implements a specific function. Validation refers to adifferent set of activities that ensure that the software that has been built istraceable to the customer requirements.

Organizing for software testing

A software testing strategy.

Criteria for completion of testing.

3. Different types of software testing Unit testing

Unit Test Considerations

Unit Test Procedures

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Integration Testing

Top-down Integration

Bottom-up Integration

Regression testing

Smoke Testing

Integration Test Documentation Validation Testing

Validation Test Criteria Configuration Review

Alpha and Beta Testing System Testing

Recovery Testing

Security Testing

Stress Testing

Performance Testing

UNIT V

1. Describe the activities of SCM in detail.

BaselinesSoftware Configuration Items

SCM Activities

Identification of objects

Version Control

Change control

Configuration audit.

Status reporting

1.Explain the different Software Cost Estimation Models.

Function Point ModelDiagram-function point model-a general scheme

i. Determine a number of items occurring in the system.ii.Unadjusted Function count is calculated by UFC=itemi wiiii.Function point FP=UFC * TCF where TCF is Technical complexity factor.

TCF=0.65+0.1fi COCOMO Model

Constructive Cost Model. Software cost estimation gives the estimation of how much months a man

take to develop a software product. Application Composition Model. Early design stage model

Post-architecture stage model. COCOMO II application composition uses object points.

OP=(object point)X[100-%reuse)/100] NOP-New Object Point. Productivity Rate, PROD=NOP/person-Month.

Delphi Method

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ProcedureThe co-ordinator presents a specification and estimation form to each expert.

Co-ordinator calls a group meeting in which the experts discuss estimationissues with the coordinator and each other.

Experts fill out forms anonymously.Co-ordinator prepares and distributes a summary of the estimates.The Co-ordinator then calls a group meeting.In this meeting theexperts mainly

discuss the points where their estimates vary widely.The experts again fill out forms anonymously.

Again co-ordinator edits and summarizes the forms,repeating steps 5and 6 until the co-ordinator is satisfied with the overall predictionsynthesized from experts.

4. Explain about Architectural Evolution in detail

Reasons to change from centralized to distributed client-server systems are:o Hardware costso User interface expectations

o Distributed access to systems

5 layers of a distributed modelo Presentation layero Data Validation layero Interaction control layer

o Application service layero Database layer

User interface distributionTwo implementation strategies for user interface distribution:

o Use Window management systemo Use WWW browser

5. Discuss about Software maintenance. Software maintenance

Three different types of software maintenance

Maintenance to repair software faults.

Maintenance to adapt the software to a different operating environment.

Maintenance to add to or modify the systems functionality.

Key factors that lead to higher maintenance cost are:

Team stability

Contractual responsibility

Staff skills

Program age and structure

Maintenance Process Maintenance Prediction

Metrics useful for assessing maintainability

Number of requests for corrective maintenance

Average time required for impact analysis

Average time taken to implement a change request

Number of outstanding change requests

6. Explain the scheduling of software projectScheduling is an activity that distributes estimated effort across the planned

project duration by allocating effort to specified software engineering tasks.

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Scheduling methods

* Program evolution and review technique (PERT)*Critical Path Method (CPM)

Timeline chart

Tracking the schedule

Time boxing

7. Explain in detail Earned value analysis(EVA)A Quantitative technique for assessing progress and percent of completion of the project.

Determine BCWS(Budgeted cost of work scheduled)

Calculate Budget at completion BAC=BCWSk Determine Budgeted cost of work performed(BCWP)

Calculate Progress indicatorsSchedule performance index SPI=BCWP

BCWSSchedule variance SV=BCWP-BCWS

Percent scheduled for completion =BCWS/BAC

Percent complete =BCWP/BAC

Determine Actual cost of work performed(ACWP)

Cost performance index CPI=BCWP/ACWP

Cost variance CV=BCWP-ACWP

8. Explain about Halsteads software science measure.

Program length

Estimated Program length N=N1+N2N1-Total number of operandsN2-Total number of operands

Actual program length N=

Program volume measure

Potential volume measure

Program level

Effort and time measure

.