Good day steemians,Good day professor @yousafharoonkhan, below is my assignment on centralised and decentralised system.

Centralisation to a layman is when power,authority, and decision making is vested at the top of higher management,centralisation in blockchain system has to do with when all the blocks in a blockchain are connected to a main server or one server which serves as the center or main source and storage of data for the blocks.

This main server controls every transaction or activities that happens on the blockchain whether be it rejection or validation of blocks, data storage and distribution and among others.
Social media platforms like Twitter Facebook and among others are all centralised systems because all transactions or activities that takes place on these platforms from any device or nodes the management have access to all these datas,the bank industry is another typical example of centralised system because users data or personal information all are available in the bank central server and can bring any policy which the user has to follow at anytime the user has no choice or preference here.

Second example the owner of Facebook can make a decision that no posting of images again and it will be dispersed around and users will follow with no choice.

On these centralised system users or nodes of the system receives instructions from the central servers thereby depending on the main server.ln the centralised system if the main server breaks down it affects all the nodes using the network.
Every node on the centralised blockchain has to be identified by the central server looking like (KYC) know your customer.

Decentralisation general definition means a system where power,decision making or control is not in the hands of any individual or group but in the hands of all members, that is evenly distributed power.

Decentralisation in blockchain system is when all the blocks that are connected to each other in the blockchain system are not controlled by any server or central server.Here the blocks have their own data stored in them and every node must come to a consensus before a transaction is termed valid or a new block is added to the blockchain.

Comparison between Centralisation and Decentralisation.

Control
Decentralisation:users have full access to their accounts such as having all the keys private, posting
and public keys,users control their own funds whether to convert funds to cryptocurrencies that is buy any crypto currency or later sell them to make more profit.data can only be altered by the user such as changing of keys,editing transactions.

Centralisation : users have no access to their keys,funds are being controlled by the main server coupled with data storage.

Fees :
Centralisation: fees charged here are high.
Decentralisation: no fees charged here.

Anonymity
Centralisation: users must be identified by the central authority or main server.

Decentralisation : users here are unknown.

Fraudulence
Centralisation : here fraudulent activities are easily tracked and brought to a halt, because all users are well identified so if any unidentified user connects any transaction it is easily identified.

Decentralisation : ln decentralisation fraudulent activities are not easily tracked because the nodes in the network are unknown so any unidentified nodes cannot be tracked.

Security :
Centralisation : it's easy to hack because all data are stored on one central server.

Decentralisation :Over here it is not easy to hack because the data are stored in several nodes connected worldwide which will be difficult to hack at the same time.

Advantages of centralisation.

1.Hastening of decision : over here change in decision are quickly taken since it only involves one server and does not involve waiting for many nodes as in decentralized system before validation can be done.

2.Fraudaulent activities are less in centralized system based on all users are well identified by the central authority.

3.Centralised system is simple and easy to use you don't need many keys to confuse you just your pin or password and you are good to go.

4.Users in centralized system ensures they follow the guidelines and protocol of the central authority.

5.Centralised system is less expensive to establish such system compared to decentralized system.

Disadvantages of centralisation.

1.Centralisation system is easily hacked since all the data are stored on one server,so hackers have to focus on targeting that particular server.

2.Centralisation system power, decision making and instruction are centered in one server based on this improved decisions cannot come from any server or node, no contribution from users.

3.Fees are highly charged by central authority to users when users perform any transaction.

4.Third party such as central authority can have access to users data without their information.

5.Users have no access to their keys.

Advantages of decentralisation.
1.Users have access to their keys and can alterate and edit data anytime and they have access to their full account.

2.Decentralised system is not easily hacked because data is connected to several nodes.

3.There is no third party here, which serves as advantage to both the sender and receiver.receiver here receives full profit and the sender does not pay any charges.

4.Everything on decentralized system is base on merit, because all the users are unknown,example on steemit,quality content creators are awarded for their content without them being known by the professors or curators.

5.No fees charge.

Disadvantages of decentralisation
1.slow decision making

2.it is expensive.

3.decentralisation is complex

4.There is misunderstanding sometimes

5.There is sometimes act of fraudulence by parties

4which one is better for business or trading.

Actually for me or in my own perspective I have controlled (smes) small and medium enterprises and with experience i think
Centralised is better for (sme) business trading because when the business is a decentralized one and all members take equal decision there will be power dragging here and misunderstanding which will not enhance the growth of the business and even some members may pull out because of these reason, but if it is a centralised one all authorities and decision comes from one source with these everyone will be adhering to that particular source and as a centralised business it will surely source for external information.

5How do you know if a blockchain is decentralized or not.

Over here I am going to use Ripple
Step1

Firstly u search for etherscan on Google and open it on the ist screen shot.
Step2
The next thing you copy the token address of Ripple and paste it on the etherscan search engine on the 3rd screenshot.

Step 3
Then click search and scroll down you will see contract on the fourth screenshot then click it it will show solidity,then carefully observe the codes.

Observation
I found out Ripple is decentralized because after observing the contract code there was no track of self destruct or functional destruct.

Conclusion.
Firstly I want to thank professor @yousafharoonkhan for such a great lectures
Overall with larger firms spread across the world I think decentralised will be better because
of division of labour, ideas or skills coming from different personnel, and may be diversifying.

Thank you

Cc:
@steemcurator01
@steemcurator02
@yousafharoonkhan