BscIT 5th

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Assignments for B.Sc. (IT) 5th Semester

Subject: Graphics & Multimedia

Subject Code: BSIT – 51

Assignment: TA (Compulsory)

1. What is the meaning of interactive computer graphics? List the various applications of the computer graphics.

Ans : The term “interactive graphics” refers to devices and systems that facilitate the man-machine graphic communication, in a way, which is more convenient than the writing convention. For example, to draw a straight line between two points, one has to input the coordinates of the two end points. In interactive graphics with the help of graphical input technique by indicating two end points on the display screen draws the line. Various applications of the computer graphics are listed below :-

I. Building Design and ConstructionII. Electronics Design

III. Mechanical DesignIV. Entertainment and AnimationV. Aerospace Industry

VI. Medical TechnologyVII. Cartography

VIII. Art and Commerce.

2. Explain in detail the Hardware required for effective graphics on the computer system.

Ans : The hardware components required to generate interactive graphics are the input device, the output device (usually display) and the computer system. The human operator is also an integral part of the interactive system. The text and graphics displayed act as an input to the human vision system and, therefore, the reaction of the human being will depend on how quickly one can see and appreciate the graphics present on the display.

3. Compare Raster scan system with random scan system.

Ans : In raster scan display, the electron beam is swept across the screen, one row at a time from top to bottom. The picture definition is stored in a memory area called refresh buffer or frame buffer. In random scan display unit, a CRT has the electron beam directed only to the parts of the screen where a picture is to be drawn. It draws a picture one line at a time and so it is referred to as vector displays.

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Raster Scan

The Most common type of graphics monitor employing a CRT is the raster-scan Display, based on television technology. In a raster- scan system; the electron beam is swept across the screen, one row at a time from top to bottom. The picture definition is stored in a memory area called the refresh buffer or frame buffer.  Each point on the screen is called pixel. On a black and system with one bit per pixel, the frame buffer is called bitmap. For systems with multiple bits per pixel, the frame buffer is referred to as a pix map. 

Refreshing on raster scan display is carried out at the rate of 60 to 80 frames per second. Some displays use interlaced refresh procedure. First, all points on the even numbered scan lines are displayed then all the points along odd numbered lines are displayed. This is an effective technique for avoiding flickering.

Random Scan Display

When operated as a random-scan display unit, a CRT has the electron beam directed only to the parts of the screen where a picture is to be drawn. Random scan monitors draw a picture one line at a time and for this reason they are also referred as vector displays (or stroke-writing or calligraphic displays). The component lines of a picture can be drawn and refreshed by a random-scan system in any specified order. A pen plotter operates in a similar way and is an example of a random-scan, hard-copy device.

Refresh rate on a random-scan system depends on the number of lines to be displayed. Picture definition is now stored as a set of line- drawing commands in an area of memory referred to as the refresh display file. Sometimes the refresh display file is called the display list, display program, or simply the refresh buffer.

4. How many colors are possible if    a. 24 bits / pixel is used    b. 8 bits / pixel is used, justify your answer

Ans : a). 24 bit color provides 16.7 million colors per pixels, That 24 bits are divided into 3 bytes; one each for the red, green, and blue components of a pixel.

    b). 256, 8 bits per pixel = 2^8 colors.

Widely accepted industry standard uses 3 bytes, or 24 bits, per pixel, with one byte for each primary color results in 256 different intensity levels for each primary color. Thus a pixel can take on a color from 256 X 256 X 256 or 16.7 million possible choices. In Bi-level image  representation one bit per pixel is used to represent black-and white images. In gray level image 8 bits per pixel to allow a total of 256 intensity or gray levels. Image representation using lookup table can be viewed as a compromise between our desire to have a lower storage requirement and our need to support a reasonably sufficient number of simultaneous colors. 

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5. List and explain different text mode built-in functions of C Programming language.

Ans : The different text mode built-in functions of C Programming language are listed below :-

i) textmode( int mode);  This function sets the number of rows and columns of the screen, mode variable can take the values 0, 1, 1, or 3. 

0: represents 40 column black and white 1: represents 40 column color 2: represents 80 column black and white 3: represents 80 column color 

Example: textmode(2); // sets the screen to 80 column black and white 

ii) clrscr(); This function clears the entire screen and locates the cursor on the top left corner(1,1)

Example clrscr(); // clears the screen 

iii) gotoxy(int x, int y); This function positions the cursor to the location specified by x and y. x represents the row number and y represents the column number. 

Example: gotoxy(10,20) // cursor is placed in 20th column of 10th row 

iv) textbackground (int color); This function changes the background color of the text mode. Valid colors for the CGA are from 0 to 6 namely BLACK, BLUE, GREEN, CYAN, RED, MAGENTA and BROWN.

Example: textbackground(2); Or //changes background color to blue textbackground(BLUE); 

v) textcolor (int color); This function sets the subsequent text color numbered between 0 to 15 and 128 for blinking.

Example : textcolor(3); // set the next text color to Green 

vi) delline (); It is possible to delete a line of text and after the deletion all the subsequent lines will be pushed up by one line

Example : /*deletes the 5th line*/ gotoxy (5,4); delline ( ); 

vii) insline(); Inserts a blank line at the current cursor position.

Example: /*inserts line at the 3rd row*/ gotoxy (3,5); insline ( ); 

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6. Write a C program to create Indian national flag.

Ans : #include"graphics.h"#include"conio.h"void main(){int gd=DETECT,gm,x,y;initgraph(&gd,&gm,"c:\\tc\\bgi");x=getmaxx();y=getmaxy();clearviewport();setfillstyle(LINE_FILL,BLUE);bar(0,0,639,479);setcolor(6);rectangle(50,50,300,200);setfillstyle(SOLID_FILL,6);bar(50,50,300,100);setfillstyle(SOLID_FILL,WHITE);bar(50,100,300,150);setfillstyle(SOLID_FILL,GREEN);bar(50,150,300,200);setcolor(BLUE);rectangle(45,45,50,300);setfillpattern(0x20,MAGENTA);bar(45,45,50,400);setcolor(BLUE);circle(175,125,25);line(175,125,200,125);line(175,125,175,150);line(175,125,150,125);line(175,125,175,100);line(175,125,159,107);line(175,125,193,143);line(175,125,159,143);line(175,125,193,107);setcolor(YELLOW);rectangle(0,0,640,43);setfillstyle(SOLID_FILL,YELLOW);bar(0,0,640,43);setcolor(BLACK);settextstyle(1,HORIZ_DIR,5);outtextxy(150,0,"INDIAN FLAG");getch();}

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Subject: Web Programming

Subject Code: BSIT – 52

Assignment: TA (Compulsory)

1. What is the meaning of Web? Explain in detail the building elements of web.

Ans : Web is a complex network of international , cross platform, and cross cultural communicating devices, connected to each other without any ordering or pattern.

There are two most important building blocks of web:

HTML and HTTP.

HTML: - HTML stands for Hyper Text Markup Language. HTML is a very simple language used to “describe” the logical structure of a document.  Actually, HTML is often called programming language it is really not.  Programming languages are “Turing-complete”, or “computable”. That is, programming languages can be used to compute something such as the square root of pi or some other such task. Typically programming languages use conditional branches and loops and operate on data contained in abstract data structures. HTML is much easier than all of that. HTML is simply a ‘markup language’ used to define a logical structure rather than compute anything. 

HTTP:  - HTTP is a “request-response” type protocol. It is a language spoken between web browser (client software) and a web server (server software) so that can communicate with each other and exchange files. Now let us understand how client/server system works using HTTP. A client/server system works something like this:  A big piece of computer (called a server) sits in some office somewhere with a bunch of files that people might want access to. This computer runs a software package that listens all day long to requests over the wires.

2. “HTML is the Language of the Web” Justify the statement.

Ans : HTML is often called a programming language it is really not. Programming languagesare ‘Turing-complete’, or ‘computable’. That is, programming languages can be used to compute something such as the square root of pi or some other such task. Typically programming languages use conditional branches and loops and operate on data contained in abstract data structures. HTML is much easier than all of that. HTML is simply a ‘markup language’ used to define a logical structure rather than compute anything.

For Example, it can describe which text the browser should emphasize, which text should be considered body text versus header text, and so forth. The beauty of HTML of course is that it

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is generic enough that it can be read and interpreted by a web browser running on any machine or operating system. This is because it only focuses on describing the logical nature of the document, not on the specific style. The web browser is responsible for adding style. For instance emphasized text might be bolded in one browser and italicized in another. It is up to the browser to decide

3. Give the different classification of HTML tags with examples for each category.

Ans : List of HTML Tags :-

Tags for Document Structure·  HTML·  HEAD·  BODY

Heading Tags·  TITLE·  BASE·  META·  STYLE·  LINK

Block-Level Text Elements·  ADDRESS·  BLOCKQUOTE. DIV·  H1 through H6·  P·  PRE·  XMP

Lists·  DD·  DIR·  DL·  DT·  LI·  MENU·  OL·  UL

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Text Characteristics·  B·  BASEFONT·  BIG·  BLINK·  CITE·  CODE·  EM·  FONT·  I·  KBD·  PLAINTEXT·  S·  SMALL

4. Write CGI application which accepts 3 numbers from the user and displays biggest number using GET and POST methods

Ans : #!/usr/bin/perl

#print "Content-type:text/html\n\n";

#$form = $ENV{'QUERY_STRING'};

use CGI;

$cgi = new CGI;

print $cgi->header;

print $cgi->start_html( "Question Ten" );

my $one = $cgi->param( 'one' );

my $two = $cgi->param( 'two' );

my $three = $cgi->param( 'three' );

if( $one && $two && $three )

{

$lcm = &findLCM( &findLCM( $one, $two ), $three );

print "LCM is $lcm";

}else{print '';print 'Enter First Number ';print 'Enter Second Number 

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';print 'Enter Third Number ';print '';print "";}print $cgi->end_html;

sub findLCM(){

my $x = shift;

my $y = shift;

my $temp, $ans;

if ($x < $y) {

$temp = $y;

$y = $x;

$x = $temp;

}$ans = $y;$temp = 1;while ($ans % $x){$ans = $y * $temp;$temp++ ;}return $ans;}

5. What is JavaScript? Give its importance in web.

Ans : JavaScript is an easy to learn way to “Script“ your web pages that is have them to do actions that cannot be handled with HTML alone. With JavaScript, you can make text scroll across the screen like ticker tape; you can make pictures change when you move over them, or any other number of dynamic enhancement.

JavaScript is generally only used inside of HTML document.

a) JavaScript control document appearance and content.

b) JavaScript control the browser.

c) JavaScript interact with document content.

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e) JavaScript read and write client state with cookies.

f) JavaScript interact with applets.

g) JavaScript manipulate embedded images.

6. Explain briefly Cascading Style Sheets

Ans : Cascading Style Sheet (CSS) is a part of DHTML that controls the look and placement of the element on the page. With CSS you can basically set any style sheet property of any element on a html page. One of the biggest advantages with the CSS instead of the regular way of changing the look of elements is that you split content from design. You can for instance link a CSS file to all the pages in your site that sets the look of the pages, so if you want to change like the font size of your main text you just change it in the CSS file and all pages are updated.

7. What is CGI? List the different CGI environment variables

Ans : CGI or “Common Gateway Interface” is a specification which allows web users to run program from their computer.CGI is a part of the web server that can communicate with other programs running on the server. With CGI, the web server can call up a program, while passing user specific data to a program. The program then processes that data and the server passes the program’s response back to the web browser.        When a CGI program is called, the information that is made available to it can be roughly broken into three groups:-

i) Information about client, server and user.ii) Form data that are user supplied.iii) Additional pathname information.

Most Information about client, server and user is placed in CGI environmental variables. Form data that are user supplied is incorporated in environment variables. Extra pathname information is placed in environment variables.

i). GATEWAY_INTERFACE – The revision of the common Gateway interface that the server uses.

ii). SERVER_NAME – The Server’s hostname or IP address.

iii). SERVER_PORT – The port number of the host on which the server is running.

iv). REQUEST_METHOD – The method with which the information request is issued.

v). PATH_INFO – Extra path information passed to the CGI program

8. What is PERL? Explain PERI control structures with the help of an example

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Ans : Perl control structures include conditional statement, such as if/elseif/else blocks as well as loop like for each, for and while.

i) Conditional statements       

- If condition – The structure is always started by the word if, followed by a condition to be evaluated, then a pair the braces indicating the beginning and end of the code to be executed if the condition is true.                   If(condition)                   {condition to be executed

}- Unless – Unless is similar to if. You wanted to execute code only if a certain condition were false.

                   If($ varname! = 23) {                   #code to execute if $ varname is not 23                   }        - The same test can be done using unless:                        Unless ($ varname== 23) {                   #code to execute if $ varname is not 23                   }ii). Looping – Looping allow you to repeat code for as long as a condition is met. Perl has several loop control structures: foreach, for, while and until.

- While Loop – A while loop executes as long as a particular condition is true:                  While (condition) {                  #code to run as long as condition is true.                   }

- Until Loop – A until loops the reverse of while. It executes as long as a particular condition is not true:

                  While (condition) {                  #code to run as long as condition is not true.                   }

Subject: Data Warehousing & Data Mining

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Subject Code: BSIT – 53

Assignment: TA (Compulsory)

1. With neat diagram explain the main parts of the computer

Ans : A Computer will have 3 basic main parts –

i) A central processing unit (CPU) that does all the arithmetic and logical operations. This can be thought of as the heart of any computer and computers are identified by the type of CPU that they use.

ii) The memory is supposed to hold the programs and data. All the computers that we came across these days are what are known as “stored program computers”. The programs are to be stored before hand in the memory and the CPU accesses these programs line by line and executes them.

iii). The Input/output devices (I/O): These devices facilitate the interaction of the users with the computer.

The input devices are used to send information to the computer, while the output devicesaccept the processed information form the computer and make it available to the user.

Diagram:-

2. Briefly explain the types of memories.

Ans : There are two types of memories – Primary memory, which is embedded in the computer and which is the main source of data to the computer and the secondary memory like floppy disks, CDs etc., which can be carried around and used in different computers. They cost much less than the primary memory, but the CPU can access data only from the primary memory. The main advantage of computer memories, both primary and secondary, is that they can store data indefinitely and accurately

3. Describe the basic concept of databases.

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Ans : The Concept of Database :- We have seen in the previous section how data can be stored in

computer. Such stored data becomes a “database” – a collection of data. For example, if all the marks scored by all the students of a class are stored in the computer memory, it can be called a database. From such a database, we can answer questions like – Who has scored the highest marks? ; In which subject the maximum number of students has failed? ; Which students are weak in more than one subject? etc. Of course, appropriate programs have to be written to do these computations. Also, as the database becomes too large and more and more data keeps getting included at different periods of time, there are several other problems about “maintaining” these data, which will not be dealt with here. Since handling of such databases has become one of the primary jobs of the computer in recent years, it becomes difficult for the average user to keep writing such programs. Hence, special languages – called database query languages- have been devised, which makes such programming easy, there languages help in getting specific “queries” answered easily.

4. With example explain the different views of a data.

Ans : Data is normally stored in tabular form, unless storage in other formats becomes advantageous, we store data in what are technically called “relations” or in simple terms as “tables”.

The views are of mainly 2 types:i) Simple Viewii) Complex View

Simple View:     - It is created by selecting only one table.    - It does not contain functions.    - It can perform DML (SELECT, INSERT, UPDATE, DELETE, MERGE, CALL,

LOCK TABLE) operations through simple view.

Complex View :    - It is created by selecting more than one table.    - It can perform functions.    - You cannot perform always DML operations through

5. Briefly explain the concept of normalization.

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Ans : Normalization is dealt with in several chapters of any books on database management systems. Here, we will take the simplest definition, which suffices our purpose namely any field should not have subfields.

Again consider the following student table. Here under the field marks, we have 3 sub fields: marks for subject1, marks for subject2 and subject3.

However, it is preferable split these subfields to regular fields as shown below Quite often, the original table which comes with subfields will have to be modified suitable, by the process of “normalization”.

6. Explain the concept of data ware house delivery process in detail.

Ans : The concept of data warehouse delivery process :-This section deals with the data warehouse from a different view point - how the different components that go into it enable the building of a data ware house. The study helps us in two ways:   i) To have a clear view of the data ware house building process.    ii) To understand the working of the data ware house in the context of the components.

Now we look at the concepts in details:-i) IT Strategy: The Company must and should have an overall IT strategy and the data ware housing has to be a part of the overall strategy.   ii) Business case analysis: This looks at an obvious thing, but is most often misunderstood. The overall understanding of the business and the importance of various components there in is a must. This will ensure that one can clearly justify the appropriate level of investment that goes into the data ware house design and also the amount of returns accruing.

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iii) Education: This has two roles to play - one to make people, especially top level policy makers, comfortable with the concept. The second role is to aid the prototyping activity.   iv) Business Requirements: As has been discussed earlier, it is essential that the business requirements are fully understood by the data ware house planner. This would ensure that the ware house is incorporated adequately in the overall setup of the organization.

v) Technical blue prints: This is the stage where the overall architecture that satisfies the requirements is delivered.

vi) Building the vision: Here the first physical infrastructure becomes available. The major infrastructure components are set up, first stages of loading and generation of data start up.

vii) History load: Here the system is made fully operational by loading the required history into the ware house - i.e. what ever data is available over the previous years is put into the data warehouse to make is fully operational.

viii) Adhoc Query: Now we configure a query tool to operate against the data ware house.

ix) Automation: This phase automates the various operational processes like - a) Extracting and loading of data from the sources. b) Transforming the data into a suitable form for analysis. c) Backing up, restoration and archiving. d) Generate aggregations. e) Monitoring query profiles.

x) Extending Scope: There is not single mechanism by which this can be achieved. As and when needed, a new set of data may be added, new formats may be included or may be even involve major changes.

xi) Requirement Evolution: Business requirements will constantly change during the life of the ware house. Hence, the process that supports the ware house also needs to be constantly monitored and modified.

7. What are three major activities of data ware house? Explain.

Ans : Three major activities of data ware house are :-  i) Populating the ware house (i.e. inclusion of data)  ii) day-to-day management of the ware house.  iii) Ability to accommodate the changes.

i) The processes to populate the ware house have to be able to extract the data, clean it up, and make it available to the analysis systems. This is done on a daily / weekly basis depending on the quantum of the data population to be incorporated.

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ii) The day to day management of data ware house is not to be confused with maintenance and management of hardware and software. When large amounts of data are stored and new data are being continually added at regular intervals, maintenance of the “quality” of data becomes an important element.   iii) Ability to accommodate changes implies the system is structured in such a way as to be able to cope with future changes without the entire system being remodeled. Based on these, we can view the processes that a typical data ware house scheme should support as follows.

8. Explain the extract and load process of data ware house.

Ans : Extract and Load Process : This forms the first stage of data ware house. External physical systems like the sales counters which give the sales data, the inventory systems that give inventory levels etc. constantly feed data to the warehouse. Needless to say, the format of these external data is to be monitored and modified before loading it into the ware house. The data ware house must extract the data from the source systems, load them into their data bases, remove unwanted fields (either because they are not needed or because they are already there in the data base), adding new fields / reference data and finally reconciling with the other data. We shall see a few more details of theses broad actions in the subsequent paragraphs.    

 i) A mechanism should be evolved to control the extraction of data, check their consistency etc. For example, in some systems, the data is not authenticated until it is audited.

ii) Having a set of consistent data is equally important. This especially happens when we arehaving several online systems feeding the data. 

iii) Once data is extracted from the source systems, it is loaded into a temporary data storage before it is “Cleaned” and loaded into the warehouse.

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9. In what ways data needs to be cleaned up and checked? Explain briefly.

Ans : Data needs to be cleaned up and checked in the following ways :-      i) It should be consistent with itself.     

ii) It should be consistent with other data from the same source.   

iii) It should be consistent with other data from other sources.     

iv) It should be consistent with the information already available in the data ware house.

While it is easy to list act the needs of a “clean” data, it is more difficult to set up systems thatautomatically cleanup the data. The normal course is to suspect the quality of data, if it does not meet the normally standards of commonsense or it contradicts with the data from other sources, data already available in the data ware house etc. Normal intuition doubts the validity of the new data and effective measures like rechecking, retransmission etc., are undertaken. When none of these are possible, one may even resort to ignoring the entire set of data and get on with next set of incoming data.

10. Explain the architecture of data warehouse.

Ans : The architecture for a data ware is indicated below. Before we proceed further, we should be clear about the concept of architecture. It only gives the major items that make up a data ware house. The size and complexity of each of these items depend on the actual size of the ware house itself, the specific requirements of the ware house and the actual details of implementation.

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11. Briefly explain the functions of each manager of data warehouse.

Ans : The Warehouse Manager : The ware house manager is a component that performs all operations necessary to support the ware house management process. Unlike the load manager, the warehouse management process is driven by the extent to which the operational management of the data ware house has been automated.

The ware house manager can be easily termed to be the most complex of the ware house components, and performs a variety of tasks. A few of them can be listed below.

i) Analyze the data to confirm data consistency and data integrity.     

ii) Transform and merge the source data from the temporary data storage into the ware house.     

iii) Create indexes, cross references, partition views etc.      

iv) Check for normalization’s.     

v) Generate new aggregations, if needed.     

vi) Update all existing aggregations     

vii) Create backups of data.     

viii) Archive the data that needs to be archived.

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12. Explain the star schema to represent the sales analysis.

Ans : Star schemes are data base schemas that structure the data to exploit a typical decision support enquiry. When the components of typical enquiry’s are examined, a few similarities stand out.

     i) The queries examine a set of factual transactions - sales for example.     

ii) The queries analyze the facts in different ways - by aggregating them on different bases /graphing them in different ways.

The central concept of most such transactions is a “fact table”. The surrounding references are called dimension tables. The combination can be called a star schema.

13. What do you mean by partition of data? Explain briefly.

Ans : Partitioning of data :- In most ware houses, the size of the fact data tables tends to become very large. This leads to several problems of management, backup, processing etc. These difficulties can be overcome by partitioning each fact table into separate partitions.

Data ware houses tend to exploit these ideas by partitioning the large volume of data into data sets. For example, data can be partitioned on weekly / monthly basis, so as the minimize the amount of data scanned before answering a query. This technique allows data to be scanned to be minimized, without the overhead of using an index. This improves the overall efficiency of the system. However, having too many partitions can be counterproductive and an optimal size of the partitions and the number of such partitions is of vital importance.

Participating generally helps in the following ways.i) Assists in better management of data

    ii) Ease of backup / recovery since the volumes are less.    iii) The star schemes with partitions produce better performance.

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iv) Since several hardware architectures operate better in a partitioned environment, the overall system performance improves.

14. Describe the terms data mart and Meta data.

Ans : Data Mart :- A data mart is a subset of information content of a data ware house, stored in it’s own data base. The data of a data ware house may have been collected through a ware house or in some cases, directly from the source. In a crude sense, if you consider a data ware house as a whole sale shop of data, a data mart can be thought of as a retailer.

Meta Data :- Meta data is simply data about data. Data normally describe the objects, their quantity and size how they are stored etc. Similarly Meta data stores data about how data (of objects) is stored etc.

Meta data is useful in a number of ways. It can map data sources to the common view of information within the warehouse. It is helpful in query management, to direct query to most appropriate source etc., the structure of Meta data is different for each process. It means for each volume of data, there are multiple sets of Meta data describing the same volume. While this is a very convenient way of managing data, managing Meta data itself is not a very easy task.

15. Enlist the differences between fact and dimension.

Ans : This ensures that key dimensions are no fact tables. Consider the following example:-

Let us elaborate a little on the example. Consider a customer A. If there is a situation, where the warehouse is building the profiles of customer, then A becomes a fact - against the name A, we can list his address, purchases, debts etc. One can ask questions like how many purchases has A made in the last 3 months etc. Then A is fact. On the other hand, if it is likely to be used to answer questions like “How many customers have made more than 10 purchases in the last 6 months”, and one uses the data of A, as well as of other customers to give the answer, then it becomes a fact table. The rule is, in such cases; avoid making A as a candidate key.

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16. Explain the designing of star-flake schema in detail.

Ans : A star flake schema, as we have defined previously, is a schema that uses a combination of demoralized star and normalized snow flake schemas. They are most appropriate in decision support data ware houses. Generally, the detailed transactions are stored within a central fact table, which may be partitioned horizontally or vertically. A series of combinatory data base views are created to allow the user to access tools to treat the fact table partitions as a single, large table. The key reference data is structured into a set of dimensions. These can be referenced from the fact table. Each dimension is stored in a series of normalized tables (Snowflake), with an additional demoralized star dimension table.

17. What is query redirection? Explain.

Ans : Query Redirection: - One of the basic requirements for successful operation of star flake schema (or any schema, for that matter) is the ability to direct a query to the most appropriate source. Note that once the available data grows beyond a certain size, partitioning becomes essential. In such a scenario, it is essential that, in order to optimize the time spent on querying, the queries should be directed to the appropriate partitions that store the date required by the query.

The basic method is to design the access tool in such a way that it automatically defines the locality to which the query is to be redirected.

18. In detail, explain the multidimensional schema.

Ans : Multidimensional schemas :- Before we close, we see the interesting concept of multi dimensions. This is a very convenient method of analyzing data, when it goes beyond the normal tabular relations. For example, a store maintains a table of each item it sells over a month as a table, in each of its 10 outlets.

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This is a 2 dimensional table. One the other hand, if the company wants a data of all items sold by its outlets, it can be done by simply by superimposing the 2 dimensional tables for each of these items – one behind the other. Then it becomes a 3 dimensional view. Then the query, instead of looking for a 2 dimensional rectangle of data, will look for a 3 dimensional cuboids of data. There is no reason why the dimensioning should stop at 3 dimensions. In fact almost all queries can be thought of as approaching a multi-dimensioned unit of data from a multidimensional volume of the schema.

19. Why partitioning is needed in large data warehouse?

Ans : Partitioning is needed in any large data ware house to ensure that the performance and manageability is improved. It can help the query redirection to send the queries to the appropriate partition, thereby reducing the overall time taken for query processing.

20. Explain the types of partitioning in detail.

Ans : i). Horizontal Partitioning :- This is essentially means that the table is partitioned after the first few thousand entries, and the next few thousand entries etc. This is because in most cases, not all the information in the fact table needed all the time. Thus horizontal partitioning helps to reduce the query access time, by directly cutting down the amount of data to be scanned by the queries.

ii). Vertical Partitioning :- As the name suggests, a vertical partitioning scheme divides the table vertically – i.e. each row is divided into 2 or more partitions.

iii). Hardware Partitioning:- Needless to say, the data ware design process should try to maximize the performance of the system. One of the ways to ensure this is to try to optimize by designing the data base with respect to specific hardware architecture.

21. Explain the mechanism of row splitting.

Row Splitting: - The method involved identifying the not so frequently used fields and putting them into another table. This would ensure that the frequently used fields can be accessed more often, at much lesser computation time. It can be noted that row splitting may not reduce or increase the overall storage needed, but normalization may involve a change in the overall storage space needed. In row splitting, the mapping is 1 to 1 whereas normalization may produce one to many relationships.

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22. Explain the guidelines used for hardware partitioning.

Ans : Guidelines used for Hardware Partitioning :- Needless to say, the data ware design process should try to maximize the performance of the system. One of the ways to ensure this is to try to optimize by designing the data base with respect to specific hardware architecture. Obviously, the exact details of optimization depend on the hardware platforms. Normally the following guidelines are useful:-

i) Maximize the processing, disk and I/O operations.ii) Reduce bottlenecks at the CPU and I/O

23. What is aggregation? Explain the need of aggregation. Give example.

Ans : Aggregation : Data aggregation is an essential component of any decision support data ware house. It helps us to ensure a cost – effective query performance, which in other words means that costs incurred to get the answers to a query would be more than offset by the benefits of the query answer. The data aggregation attempts to do this by reducing the processing power needed to process the queries. However, too much of aggregations would only lead to unacceptable levels of operational costs. Too little of aggregations may not improve the performance to the required levels. A file balancing of the two is essential to maintain the requirements stated above. One thumb rule that is often suggested is that about three out of every four queries would be optimized by the aggregation process, whereas the fourth will take it’s own time to get processed. The second, though minor, advantage of aggregations is that they allow us to get the overall trends in the data. While looking at individual data such overall trends may not be obvious, whereas aggregated data will help us draw certain conclusions easily.

24. Explain the different aspects for designing the summary table.

Ans : Summary table are designed by following the steps given below :- i) Decide the dimensions along which aggregation is to be done. ii) Determine the aggregation of multiple facts. iii) Aggregate multiple facts into the summary table. iv) Determine the level of aggregation and the extent of embedding. v) Design time into the table. vi) Index the summary table.

25. Give the reasons for creating the data mart.

Ans : The following are the reasons for which data marts are created :-    i) Since the volume of data scanned is small, they speed up the query processing.    ii) Data can be structured in a form suitable for a user access too    iii) Data can be segmented or partitioned so that they can be used on different platforms and also different control strategies become applicable.

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26. Explain the two stages in setting up data marts.

Ans : There are two stages in setting up data marts :-

i) To decide whether data marts are needed at all. The above listed facts may help you todecide whether it is worthwhile to setup data marts or operate from the warehouse itself.The problem is almost similar to that of a merchant deciding whether he wants to set up retailshops or not.

ii) If you decide that setting up data marts is desirable, then the following steps have to be gone through before you can freeze on the actual strategy of data mart.

a) Identify the natural functional splits of the organization.b) Identify the natural splits of data.c) Check whether the proposed access tools have any special data base structures.d) Identify the infrastructure issues, if any that can help in identifying the data marts.e) Look for restrictions on access control. They can serve to demarcate the warehousedetails.

27. What are disadvantages of data mart?

Ans : There disadvantages of data mart are:- i) The cost of setting up and operating data marts is quite high. ii) Once a data strategy is put in place, the data mart formats become fixed. It may be fairly difficult to change the strategy later, because the data marts formats also have

to be changes.

28. What is role of access control issue in data mart design?

Ans : Role of access control issue in data mart design :- This is one of the major constraints in data mart designs. Any data warehouse, with it’s huge volume of data is, more often than not, subject to various access controls as to who could access which part of data. The easiest case is where the data is partitioned so clearly that a user of each partition cannot access any other data. In such cases, each of these can be put in a data mart and the user of each can access only his data. In the data ware house, the data pertaining to all these marts are stored, but the partitioning is retained. If a super user wants to get an overall view of the data, suitable aggregations can be generated.

29. Explain the purpose of using metadata in detail.

Ans : Metadata will be used for the following purposes :- i) Data transformation and loading. ii) Data management. iii)Query generation.

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30. Explain the concept of metadata management.

Ans : Meta data should be able to describe data as it resides in the data warehouse. This will help the warehouse manager to control data movements. The purpose of the metadata is to describe the objects in the database. Some of the descriptions are listed here.

· Tables- Columns

* Names* Type

· Indexes- Columns

* Name* Type

· Views- Columns

* Name* Type

· Constraints- Name- Type- Table

* Columns

31. How the query manager uses the Meta data? Explain in detail.

Ans : Meta data is also required to generate queries. The query manger uses the metadata to build a history of all queries run and generator a query profile for each user, or group of uses.We simply list a few of the commonly used meta data for the query. The names are self explanatory.

o Queryo Table accessed

§ Column accessed· Name· Reference identifier

o Restrictions appliedo Column nameo Table nameo Reference identifiero Restrictions

o Join criteria appliedo Column nameo Table nameo Reference identifiero Column nameo Table name

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o Reference identifier

o Aggregate function usedo Column nameo Reference identifiero Aggregate function

o Group by criteriao Column nameo Reference identifiero Sort direction

o Syntax

o Resources

o Disko Reado Writeo Temporary

32. Why we need different managers to a data ware house? Explain.

Ans : Need for managers to a data ware house :- Data warehouses are not just large databases. They are complex environments that integrate many technologies. They are not static, but will be continuously changing both content wise and structure wise. Thus, there is a constant need for maintenance and management. Since huge amounts of time, money and efforts are involved in the development of data warehouses, sophisticated management tools are always justified in the case of data warehouses. When the computer systems were in their initial stages of development, there used to be an army of human managers, who went around doing all the administration and management. But such a scheme became both unwieldy and prone to errors as the systems grew in size and complexity. Further most of the management principles were adhoc in nature and were subject to human errors and fatigue.

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33. With neat diagram explain the boundaries of process managers.

Ans : A schematic diagram that defines the boundaries of the three types of managers :-

34. Explain the responsibilities of each manager of data ware house.

Ans : Ware house Manager :- The warehouse manager is responsible for maintaining data of the ware house. It should also create and maintain a layer of Meta data. Some of the responsibilities of the ware house manager are :

o Data movemento Meta data managemento Performance monitoringo Archiving.

Data movement includes the transfer of data within the ware house, aggregation, creation andmaintenance of tables, indexes and other objects of importance. It should be able to create new aggregations as well as remove the old ones. Creation of additional rows / columns, keeping track of the aggregation processes and creating Meta data are also it’s functions.

35. What are the different system management tools used for data warehouse?

Ans : The different system management tools used for data warehouse :- i) Configuration Managers ii) Schedule Managers iii) Event Managers iv) Database Mangers v) Back up Recovery Managers vi) Resource and performance a monitors

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Subject: Software Quality & Testing

Subject Code: BSIT – 54

Assignment: TA (Compulsory)

1. What is software testing? Software testing is tougher than hardware testing, justify your answer.

Ans : Software testing means check the correctness and completeness of a product or a project with respect to client requirement is known as software testing. Software testing is a critical element of software quality assurance and represents the ultimate process to ensure the correctness of the product. The quality of product always enhances the customer confidence in using the product thereby increasing the business economics.

Software testing is tougher than hardware testing as because you need to make sure it works with all the hardware, operating systems, system versions, interfaces, and different countries, languages etc.

2. Explain the test information flow in a typical software test life cycle.

Ans : In every organization testing is an important phase in the development of a software product. However, the way it is carried out differs from one organization to another. It is advisable to carry out the testing process from the initial stages, with regard to the Software Development Life Cycle to avoid any complications. Testing is a complex process and requires efforts similar to software development.

Software Configuration includes a Software Requirements Specification, a Design Specification, and source code.

A test configuration includes a Test Plan and Procedures, test cases, and testing tools.

It is difficult to predict the time to debug the code, hence it is difficult to schedule.

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Once the right software is available for testing, proper test plan and test cases are developed. Then the software is subjected to test with simulated test data. After the test execution, the test results are examined. It may have defects or the software is passed without any defect. The software with defect is subjected to debugging and again tested for its correctness. This process will continue till the testing reports zero defects or run out of time for testing.

3. What is risk in software testing? How risk management improves the quality of the software?

Ans : Risk are future uncertain events with a probability of occurrence and a potential for loss” Schedule Risk:

Budget Risk: Operational Risks: Technical risks: Programmatic Risks:

Risk Management Software is used to balance risk with potential reward. It is used by insurance companies to determine insurance rates for clients without posing too much risk to the company.

4. Explain the black and white box testing? Explain with an example. Which method better? List out drawbacks of each one.

Ans : Black-box testing - This testing looks at the available inputs for an application and the expected outputs that should result from each input. It does not have any relation with the inner workings of the application, the process undertaken or any other internal aspect of the application.

White-box testing - This testing looks into the complex inner working of the application; it tests the processes undertaken and other internal aspects of the application. While black box testing is mainly concerned with the inputs and outputs of the application

5. What is cyclomatic complexity? Explain with an illustration. Discuss its role in software testing and generating test cases.

Ans : Cyclomatic complexity (or conditional complexity) is a software metric (measurement). It was developed by Thomas J. McCabe, Sr. in 1976 and is used to indicate the complexity of a program. It directly measures the number of linearly independent paths through a program's source code.

6. What is coupling and cohesion? Mention different types of coupling and cohesion. Explain their role in testing.

Ans : Cohesion and Coupling deal with the quality of an OO design. Generally, good OO design should be loosely coupled and highly cohesive. Lot of the design principles, design patterns which have been created are based on the idea of “Loose coupling and high cohesion”.

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The aim of the design should be to make the application: Easier to develop Easier to maintain Easier to add new features Less Fragile.

Content coupling (high)Common couplingExternal couplingData couplingNo coupling

7. Compare and contrast between Verification and Validation with examples.

Ans : Verification typically involves reviews and meetings to evaluate documents, plans, code, requirements, and specifications. This can be done with checklists, issues lists, walkthroughs, and inspection meetings. Validation typically involves actual testing and takes place after verifications are completed.

8. What is stress testing? Where do you need this testing? Explain.

Ans : Stress testing is a form of testing that is used to determine the stability of a given system or entity. It involves testing beyond normal operational capacity, often to a breaking point, in order to observe the results. Stress testing may have a more specific meaning in certain industries, such as fatigue testing for materials. Stress testing is a form of testing that is used to determine the stability of a given system or entity. It involves testing beyond normal operational capacity, often to a breaking point, in order to observe the results.

9. Software testing is difficult than implementation. Yes or no, justify your answer.

Ans : Yes software testing is difficult than implementation You need to make sure it works with all the hardware, operating systems, system versions, interfaces, and different countries, languages. Testing a specific part of a system or even a program. That would be called a component. So it is component testing.

10. What are test cases? Explain the importance of Domain knowledge in test case generation. Mention the difficulties in preparing test cases

Ans : A test case in software engineering is a set of conditions or variables under which a tester will determine whether an application or software system is working correctly or not. The mechanism for determining whether a software program or system has passed or failed such a test is known as a test oracle. In some settings, an oracle could be a requirement or use case, while in others it could be a heuristic. It may take many test cases to determine that a software program or system is considered sufficiently scrutinized to be released.

Domain knowledge is valid knowledge used to refer to an area of human endeavor, an autonomous computer activity, or other specialized discipline. Specialists and experts use and develop their own domain knowledge. If the concept domain knowledge or domain expert is used, we emphasize a specific domain which is an object of the discourse/interest/problem.

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