How to write Δ and δ easily in word?

Press Alt and  += tab simultaneously.  Then a equation editor will appear like below

In the editor , type for \Delta for Δ and \delta for δ.

visulaization of network

Havel-Hakimi Algorithm: Find the existence of a simple graph from a given degree sequence

We can find out whether a simple graph exist corresponding to a given degree sequence using Havel-Hakimi Algorithm


Step 1: Put degree sequence in non-ascending order.
Step 2:  Remove highest degree (K)   
Step 3: Subtract 1 from next K entries
Step 4: Repeat step 1, 2 and 3 until

(i)                  If we get all zero entries ----> Simple graph exist

(ii)                If we get at least one negative entry --->   Simple graph does not exist

(iii)               Not enough degree or entries ---> Simple graph does not exist.

For example

(     1)    3,2,1,1,0  

       Solution: No graph exist
                     Reason: The sum of degrees of a graph is even

(     2)    3,2,1,0,0

      Solution:
          Step 1: It is already in non-ascending sequence.
          Step 2: We get the value of K=3.  After removal of highest degree, the sequence becomes (2,1,0,0)
          Step 3: We subtract 1 from K=3 entries (2,1,0) from the whole sequence (2,1,0,0). Then the sequence becomes (1,0,-1,0)
          Step 4: We stop here as we get one negative entry in the sequence.
                       Conclusion: no simple graph exists.

3)  8,7,7, 6, 4,2,1,1
       Solution: 
                

          Step 1: It is already in non-ascending sequence.

          Step 2: We get the value of K=8.  After removal of highest degree, the sequence becomes (7,7, 6, 4,2,1,1)

         Step 3: We have to subtract 1 from K=8 entries. But we have only 7 entries.

                        Conclusion: no simple graph exists.

4) 7,6,5,4,4,3,2,1

Solution: Simple graph exists. You will get all 0 entries if you follow the above procedure.

UGC NET: Characteristics of Research

1. Controlled: It means in exploring causality in relation to two variables, you set up your study in a way that minimizes the effect of other variables affecting the relationship.

note: causality means cause + effect

2. Rigorous;

 The procedure followed to find answers to questions are relevant, appropriate and justified.

3. Systematic:

The procedures in an investigation should follow a certain logical sequence. the different steps can not be taken in a haphazard way. Some procedure must follow others.

4. Valid:

Whatever you conclude on the basis of your findings should be correct and can be verified by you and others.

5. Verifiable

6. Reliable:

Whatever you co  Research method should produce stable and consistent results. (RC-Reliable Consistency)

A measure is considered to be reliable if same result comes when a number of times it is processed.

number of times produces the same result.

Validity vs Reliability

valid is always reliable but vice versa is not true.

Valid means accurate. (VA)

Reliable means consistent (RC)

Validity is more important than reliablility.

6. Empirical:--> Experience

Any conclusion drawn are based on hard evidence gathered from information collected from real life experiences or observations.

7. Critical

The process of investigation must be fool proof and free from any drawbacks.

8. Credibility or veracity

 Researchers should tell the truth and pass on information in a comprehensive and objective way.

9. Cyclic process

 Should start with a problem and end with a problem.

Credits: Aditim Ma'am (unacademy)  PS: I am just taking notes after listening her videos. I think it may be helpful to others as well. For better understanding please listen her videos.

UGC NET: Hypothesis

1. What is hypothesis ?
Ans:  A mere assumption or some supposition to be proved or disproved.

*For a reseracher, it is a formal question that he intends to resolve.

* Research hypothesis is  predictive statement, which can be tested by scientific methods, that relates an independent varaible to depdendent variable. (previous year question)

2. Is it possible to conduct research without creating hypothesis?

3. why it is important ?
4. When a hypothesis is called best ?


Credits: Aditim Ma'am (unacademy) 
PS: I am just taking notes after listening her videos. I think it may be helpful to others as well. For better understanding please listen her videos.

Alphabet: A finite set of symbols

Alphabet: A finite set of symbols.
Σ={0,1}

String: A finite sequence of symbols from an alphabet.
S=1010

Language : A set of strings.

B={w|w represents an even number}

Countable Set: A set is countable if it is finite or one to one correspondence with the natural numbers.

What is the best way to learn OSI model layers?

• The best way to learn OSI model layers is to follow a book and visualize the concepts.

 One of my seniors has suggested "Computer Networking A Top-down approach by Kurose and Ross". From my experience, it is an excellent book to understand OSI models better.

• Another point from my experience to read this paper: THE DESIGN PHILOSOPHY OF THE DARPA INTERNET PROTOCOLS David D. Clark 

In most cases we know how a protocol works but we never mind why it is like that. To know the hidden motivation and reasoning why TCP-IP is designed like that, please read the above paper.