IT 2251 SOFTWARE ENGINEERING AND QUALITY ASSURANCE

UNIT –III Analysis, Design Concepts And PrinciplesTwo marks

1. Define software design.Software design is an iterative process through which requirements are translated

into a “blue print” for constructing the software. Design provides software representation that can be assessed for quality.

2. What are the elements of Analysis model?i. Data Dictionaryii. Entity Relationship Diagramiii. Data Flow Diagramiv. State Transition Diagramv. Control Specificationvi. Process specification

3. What are the elements of design model?vii. Data designviii. Architectural designix. Interface designx. Component-level design

4. Define design process.Design process is a sequence of steps carried through which the requirements are translated into a system or software model.

5. List the principles of a software design.a. The design process should not suffer from “tunnel vision”.b. The design should be traceable to the analysis model.c. The design should exhibit uniformity and integration.d. Design is not coding.e. The design should not reinvent the wheel.

6. How do you define architectural design?The initial design process of identifying the sub system and establishing a framework for

sub system control and communication is called architectural design.(or)

What is architectural design?It is way that describes the components, connectors, constraints and semantics models.

7. What is the benefit of modular design?Changes made during testing and maintenance becomes manageable and

they do not affect other modules.

8. What is a cohesive module?A cohesive module performs only “one task” in software procedure with

little interaction with other modules. In other words cohesive module performs only one thing.

9. What are the different types of Cohesion?a. Coincidentally cohesive –The modules in which the set I\of tasks are related

with each other loosely then such modules are called coincidentally cohesive.

b. Logically cohesive – A module that performs the tasks that are logically related with each other is called logically cohesive.

c. Temporal cohesion – The module in which the tasks need to be executed in some specific time span is called temporal cohesive.

d. Procedural cohesion – When processing elements of a module are related with one another and must be executed in some specific order then such module is called procedural cohesive.

e. Communicational cohesion – When the processing elements of a module share the data then such module is called communicational cohesive.

10. What is coupling?Coupling is the measure of interconnection among modules in a program

structure. It depends on the interface complexity between modules. (or)

Define CouplingCoupling is a measure of intermodule connectivity, and is concerned with

identifying the forms of connection that exist between modules and the strength of these connections.

11. Define Cohesion.Cohesion provides a measure of the extent to which the components of a module

can be considered to be functionally related.

12. What are the various types of coupling?a. Data coupling – The data coupling is possible by parameter passing or data

interaction.b. Control coupling – The modules share related control data in control

coupling.c. Common coupling – The common data or a global data is shared among

modules.d. Content coupling – Content coupling occurs when one module makes use of

data or control information maintained in another module.

13. What are the common activities in design process?a. System structuring – The system is subdivided into principle subsystems

components and communications between these subsystems are identified.b. Control modeling – A model of control relationships between different parts

of the system is established.

c. Modular decomposition – The identified subsystems are decomposed into modules.

14. What are the benefits of horizontal partitioning?a. Software that is easy to test.b. Software that is easier to maintain.c. Propagation of fewer side effects.d. Software that is easier to extend.

15. What is vertical partitioning?Vertical partitioning often called factoring suggests that the control and

work should be distributed top-down in program structure.

16. What are the advantages of vertical partitioning?a. These are easy to maintain changes.b. They reduce the change impact and error propagation.

17. What are the various elements of data design?a. Data object – The data objects are identified and relationship among various

data objects can be represented using ERD or data dictionaries.b. Databases – Using software design model, the data models are translated

into data structures and data bases at the application level.c. Data warehouses – At the business level useful information is identified

from various databases and the data warehouses are created.

18. List the guidelines for data design.a. Apply systematic analysis on data.b. Identify data structures and related operations.c. Establish data dictionary.d. Use information hiding in the design of data structure.e. Apply a library of useful data structures and operations.

19. Mention some of the characteristics of good design.Design must accommodate and implement all the requirements as desired by the

customer.Design should provide a complete picture of the software that address all the software

elements.Design should be modular and understandable.It should contain distinct representation of data and appropriate data structure,

architecture, independent functional characteristics and interfaces with reduced complexity.

A design should be derived using a repeatable method during software requirement analysis.

20. Name the commonly used architectural styles.a. Data centered architecture.b. Data flow architecture.

c. Call and return architecture.d. Object-oriented architecture.e. Layered architecture.

21. Name the two types of information flow: Transform flow Transaction flow

22. What is meant by Transaction?In many software applications, a single data item triggers one or a number of

information flows that affect a function implied by the triggering data item. Such data item is called as transaction.

23. 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.

24. Define: user-interface design. (or) what is user interface design?

User-interface design is a design process of identifying users, task, defining a set of interface objects and actions, and forming the screen layout for human interaction with the system.

25. What is the Purpose of user-interface design?User interface design creates an effective communication medium between a

human and a computer.

26. Mention the golden rules for designing user-interface Place the user in control. Reduce the user’s memory load. Make the interface consistent.

27. List out the interface design models. Design model User model User’s model System image

28. Name the activities involved in user-interface design process. User, task, and environment analysis Interface design Interface construction Interface validation

29. Write the interface design steps. Establish the goals and intentions for each task Map goal to actions

Specify the action sequence Indicate the state of the system Define control mechanisms

30. What are the common design issues in designing user-interface? System response time User help facilities Error information handling Command labeling

31. Mention the activities involved in interface validation. The ability of the interface to implement every user task correctly. The degree to which the interface is easy to use and easy to learn. The user’s acceptance of the interface.

32. Mention the three areas that interface design focuses the attention. The design of interface between software components. The design of interfaces between the software and other non

human producers or consumers of information. The design of the interface between a human and a computer.

33. What is a 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.

34. Define: Real time system.System that works according to real world events. Correct functionality

depends on results produced and the time at which the results are produced.

35. What is a Real time software Design?Designing software system embedded in some large hardware system,

whose behavior is subject to timing constraints.

36. Mention the types of Real time system. The two types of Real time system are,

Soft Real-time system Hard Real-time system

37. What is meant by Soft Real-time system? (Or) Define: 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.

38. What is meant by Hard Real-time system? (Or) Define: Hard Real-time system.

A hard real time system is a system whose operation is incorrect if results are not produced according to the timing specification.

39. Differentiate periodic and aperiodic stimuli.

Periodic Aperiodic stimuli.It occur at predictable time interval for example, the system examines the sensor every 20 msec.

Aperiodic stimuli occur irregularly.

Signaled by timer clock. They are usually signaled by computer interrupt mechanism.

Generated by sensors. Generated either by the actuators or by sensors.

40. Mention the classes of Stimuli.

Periodic stimuli – stimuli which occur at predictable time intervals.EX: A temperature sensor may be polled 10 times per second.

Aperiodic stimuli- stimuli which occur at unpredictable time intervals.EX: A system power failure.

41. Mention the steps in designing real time system. The steps in designing real time system:

Identify the stimulus and responses. Identify timing constraints Aggregate the stimulus and response into concurrent processes. Design algorithms Design scheduling system Integrate the system under the control of real time executive.

42 What are the components of a real time executive? A real time clock An interrupt handler A scheduler A resource manager A dispatcher

43. Name the priority levels of real time systems. Interrupt level Clock level

44. Mention the real time system users.Categories of users:

Novice Knowledgeable, intermittent users Knowledgeable, frequent users.

45. What is system response time?System response time is measured from the point at which the user

performs some control action until the software responds with desired output or action.

46. What are the various real time systems classes?There are number of standard systems classes such as

Monitoring system Data acquisition system Command and control system

47. State the golden rules for designing user-interface. Place the user in control. Reduce the user’s memory load. Make the interface consistent.

48. State the set of user-interface design principles?The set of user-interface design principles are:

User familiarity Consistency Minimal surprise Recoverability User guidance User diversity Hide technical internals

49. What is an architectural style?The architectural style describes a system category that encompasses a set

of components, a set of connector’s constraints and semantic models.

50. Mention steps in transaction mapping. Review the fundamental system model Review and refine data flow diagrams for the software. Determine transaction center. Factor and refine the transaction structure Refine the first – iteration architecture using design heuristics.

51. What is Data design?The Data design transform the information domain model created during

analysis into the data structure that will be required to implement the software.

52. What is Architectural design?The Architectural design define the relationship between major structural

elements of the software, the “design patterns” that can be used to achieve the

requirements that have been defined for the system , and the constraints that affect the way in which the architectural design patterns can be applied.

53. What are Monitoring and Control Systems?A burglar alarm system is primarily a monitoring system. It collects data

from sensors but no real time actuator control. Control systems are similar but, in response to sensor values, the system sends control signal to actuators. Example: Monitors temperature and switches heaters ON and OFF.

54. What are data Acquisition Systems?Systems that collect data from sensor for subsequent processing and

analysis are termed as Data acquisition systems. Data collection processes and processing processes may have different periods and deadlines.

PART B1. Explain the design concepts in detail.2. What are the different architectural styles for software design and explain each

design in detail.3. Explain the steps involved in transform mapping.4. Explain the steps involved in transaction mapping.5. i) Write short notes on design heuristics.

ii) Explain data acquisition system in detail.6. Give the general model of real time system and explain how real time system

designed?7. Illustrate the monitoring and control system with an example.8. Discuss in detail about design process in software development.9. i) Draw a diagram for Design model.

ii) Explain the Design Documentation.10. Write short notes on

i) Real Time Systemsii) Real Time Executivesiii) Data Acquisition Systemiv) Monitoring and Control System

11. Write short notes on User Interface Design, activities and its design principles. 12. Describe the fundamental software design concepts and explain the criteria for

modular design method evaluation. 13. i) Describe the concepts of information hiding .

ii) Discuss the modular design concepts with all its criteria.14. Explain the basic design principle in detail.15. Discuss the design procedure for Real Time System.16. What is cohesion? Explain the different types of cohesion and coupling with

examples.17. Explain architectural design process in detail with neat diagram.18. Describe the various system structuring models.19. Discuss the impact of cohesion, coupling, fan-in, fan-out and factoring in design

phase.

20. Give the general model of a Real Time System and explain how does a Real Time System designed?

21. Explain Data Acquisition System in detail.22. Briefly explain the roles performed by Real Time Executives do for the

functioning of Real Time System?23. Explain horizontal partitioning and vertical partitioning.24. Explain the System Engineering in detail.25. i) Write short notes on Analysis concepts.

ii) Summarize the steps involved in data design process.