U.G.C. NET Exam. 24 June, 2019 Paper–II (COMPUTER SCIENCE & APPLICATIONS)

statements P : In software engineering, defects that are discovered, defects that are discovered earlier are more expensive to fix. This statement is not correct. In software engineering, defects which are early detected are easier to fix.

It reduces error fixing cost. It increases the productivity. Early defect detection improves the overall quality of software.
Statement Q : A software design is said to be a good design, if the components are strongly cohesive and weakly coupled.

Coupling : Coupling in software engineering mean interdependence between the modules. Cohesion means how the elements of one module are related with each other. It means intra-dependency between the module. For a good software design, low coupling and high cohesion is desired.

MODEL-VIEW-CONTROLLER (MVC):
*MVC refers to three different realms of responsibility in the design of a graphical user interface.
* when the MVC pattern is applied to a component the model consists of the data that represents the current state of the component.
* The view is simply the visual presentation of the component on the screen.
* The controller is the aspect of the component that carries out actions in response to events generated by the user (or by other source such as timers). The idea is to assign responsibility for the model, the view, and the controller to different objects.

A minimal test set that achieves 100% path coverage will also achieve 100% statement coverage. This statement is correct statement coverage means executing each statement at least once. Where as Path coverage is in which every distinct entry- exit path through the code is executed at least once in some test. It is a white box technique. It tells about how well the source code has been made. A minimal test set that achieves 100% path coverage will also achieve 100% statement coverage.

Statement Q : A minimal test set that achieves 100% path coverage will generally detect more faults than one that achieves 100% statement coverage Sometimes, during minimal test it can be the possibility that test suite produce 100% statement coverage will miss certain defects related to control structure. So this statement is correct.

Statements R : A minimal test set that achieves 100% statement coverage, will generally detect more faults than one that achieves 100% branch coverage.

Branch coverage means, for each branch is chosen at least once in some test. It includes statement coverage. As, in case of statement coverage, test suite sometimes cannot detect all faults. So this statement is not correct that minimal test set that achieves 100% statement coverage will generally detect more faults than one that achieve 100% branch coverage.

"Software reuse is the process of creating new software system from predefined software components."

Git is an open source distributed version control system. Version control is a system that records changes to a file or set of files over time. So that you can recall specific versions later. * Local version control system : In this, files are copied into another directory. This approach is very common. In this it is easy to forget which directory you are in and accidentally write to the wrong file.

* Centralized version control system : The next issue people encounter that they need to collaborate with developers on other systems. These systems have a single server that contains all versioned files and number of clients that check out file from central place. Main disadvantage is that a single point of failure can cause the entire system.

* Distributed version control system : In this, client do not just check out the latest snapshot of the files, they fully mirror the repository. Thus, if any server dies and these systems were collaborating via it, any of the client repositories can be copied back up to the server to restore it. Every clone is fully backup of all the data.

Integrity of web application :
Integrity of web application can be found out using the security and threat in that.
Formula : Integrity = [1 – threat (1 – security)] Calculation -
It is given that, probability or Likelihood of repelling an attack = 30%
i.e probability of security = 0.30
Threat probability is given as 25% or 0.25
So integrity = [1 – 0.25 (1 – 0.30)]
integrity = [1 – 0.25 (0.70)]
Integrity = 1 – 0.175 = 0.825

(A) Waterfall model- (iv) Automate the manual system for student record maintenance in a school
(B) Incremental development - (i) e-business software that starts with only the basic functionalities and then moves to more advanced features
(C) Prototyping - (iii) A virtual reality system for simulating vehicle navigation in a highway (D) RAD - (ii) An inventory control system for a super-market to be developed within three months

Maintenance :- Maintenance can be referred as a process of enhancement in the software product according to the changing requirements of users. Four types of maintenance :
1– Adaptive : Modifying the system to cope with changes in the software environment (DBMS, OS),
2– Perfective : implementing new or changed user requirements which concern functional enhancements to the software.
3– Corrective : diagnosing and fixing errors, possibly ones found by users.
4– Preventive : Increasing software maintainability or reliability to prevent problems in the future.

Risk monitoring and control in software engineering ensures the execution of risk plans and help in reducing the risk in software projects. It keeps track of identifies risks. It monitors the already occurring risks and can identify new risks in project execution. Primary objectives of risk monitoring are :
1) To assess whether predicted risk do occur.
2) To ensure that risk aversion steps defined for the risk are being properly applied.
3) To collect information that can be used for future risk analysis.
4) To verify that risk actions are as effective as expected.
5) Proper procedures are followed or not.
6) To identify the new risk that were not occured previously.
7) To identify whether the risk has changed or declined.
Risk monitoring helps in identifying the events that has a serious effect in controlling the risks It can produce alternate path for execution of events. It provides a good quality software after monitoring and controlling all the risks that can occur during the execution of software project.

Software validation means "are we building the right product".
Validation means that product meets the customers expectations. It goes beyond checking it meats its specification as system specifications don't always accurately reflect the real need of users.

Validation refers to the process of evaluating software at the end of its development to ensure that it is free from failure and implies with its requirement A failure is defined as incorrect product behaviors often the validation occurs through the utilization of various testing approaches.
There are two ways to perform software validation internal and external.
1– Internal validation assumes that goals of stakehoding were correctly understood.
2– External validation is performed by asking the stake holders if the software meets their needs.