Six Degrees Of Separation

Six Degrees of Separation

Six degrees of separation is the theory that anyone on the planet can be connected to any other person on the planet through a chain of acquaintances that has no more than five intermediaries. The theory was first proposed in 1929 by the Hungarian writer Frigyes Karinthy in a short story called "Chains." Most people have heard of the "six degrees of separation" theory -- the idea that everyone in the world is separated from everyone else by six links. Is it a myth or a fact of life?

A 'degree of separation' is a measure of social distance between people. You are one degree away from everyone you know, two degrees away from everyone they know, and so on. The concept was popularised by John Guare's 1990 play, Six Degrees of Separation, which was turned into a film starring Will Smith, Stockard Channing, Donald Sutherland and Ian McKellen.

Starting from Stanley Millgram in 1967, many people have experimented on the topic and the fight still continues. that involved sending folders or letters from a group of people in one part of the country to a specific person they didn't know in another part of the country. The people were told to get the material to someone who might know someone that would know the individual.  In fact, he found that the letters or folders took, on average, between five and six connections to reach the intended recipient. Though the average number of links was five or six, the majority of the connections ranged from two to 10 links. In spite of being challenged by Judith S.Kleinfeld, Milgram's work was revolutionary as it paved way to more discussion and understanding.

Six degrees of separation

In 2003, Duncan Watts and colleagues at Columbia University, asked emailers to try and forward a message to one of 18 target people in 13 different countries, going via their friends and acquaintances. All together more than 60,000 people took part. They found that successful chains were completed in between 5 and 7 steps, similar to Milgram’s results. Leskovec and Horvitz for Mcrosoft in 2006, analysed data from 30 billion instant messages sent around the world and found average number between senders is a slightly bigger 6.6.  In august 15, 2015, Derek Muller of Veritasium has come up with a  a scientific explanation which makes it  easier to maintain connections with distant acquaintances than ever before. For example, Muller explained that in 2011 Facebook analysed their data and found that 92 percent of all their users were connected through just five steps. Moreover Facebook, the online social network, has a 'six degrees' application to test the theory through the connections of Facebook users. That may reduce a degree or two: Barack Obama already has well over a million Facebook friends.

A site called Six Degrees, launched in 1997, is considered  to be the first social networking site and the precursor of sites like facebook which have effectively lowered the number of intermediaries in the chain, arguably to almost zero.  Remember that we are not talking about the chances of connection between two people taken at random. We are talking about the chances of meeting a person who knows someone from our past. Over a lifetime, these chances are high, especially for educated people who travel in similar networks. In the digital age, the world has shrunk more, turning us into a "global village."  So lets test this to know a fact or myth!!!!!

You can definitely test theory yourself; initially I also had some doubt about the credibility of this theory as everyone else. Then I did a experiment by sending E-mail to some of my school friends,  reality is I even did not know the E-mail address of my school friends, I just know their name and place where they use to live around 20 years back. In my mail, I explained their physical appearance based on my assumption.  And I requested one of my nephews to pass this mail to my school friend whom I explained in the mail or someone who might know my school friend. I’m really surprised and happy that I can able to contact 7 school friends out of 10. Any way 3 of my school friends did not reply or they did not get my message.  And some of my friends got my message from multiple sources. In my experiment lowest chain in 4 and highest is 11.

Any way I am happy with my experiment because it helped me to understand how close we are even when we did not know. It really helped me to establish connection with my old friends, whom I thought I lost connection.  After that I tried to contact individuals in the chain unfortunately most of them did not reply, thinking it’s a Spam message.....

I request you to please try from your side and please share your experience....  Please note that it will take some time so be patient, as still I am waiting for my unconnected 3 friends.... 

The Li-Fi: Internet Revolutioner

Due to the increasing demand for wireless data communication, the available radio spectrum below 10 GHz (cm-wave communication) has become insufficient. The wireless communication industry has responded to this challenge by considering the radio spectrum above 10 GHz (mm-wave communication). The answer to increasing frequency congestion as Internet usage continues to rise across the world is provided by Light-Fidelity (Li-Fi). It’s a very exciting technology that has been on our radar since Professor Harald Hass gave a TED talk on the topic back in 2011.

Light-Fidelity (Li-Fi) is a continuation of the trend to move to higher frequencies in the electromagnetic spectrum. Data is transmitted by modulating the intensity of LED light at nanosecond intervals, too quick to be detected by the human eye. It uses visible light between 400 and 800 THz (780–375 nm) to transmit binary data in the form of light pulses. Actually how it works- Li-Fi uses common household LED (light emitting diodes) lightbulbs to enable data transfer, boasting speeds of up to 224 gigabits per second. Standard LED lightbulbs use a constant current, which emits a constant stream of photons perceived by us as visible light. LEDs are semiconductors so the current and output can be modulated at high speeds, which is picked up via a photodetector device. The optical output is then converted back into an electrical current, which is processed and sent to your device as data. Li-Fi depends on your device being within range of the light being transmitted by your Li-Fi bulb. 

Li-FI Block Diagram

Why we use LEDs specifically? Its because LED bulbs use 85% less energy than incandescent bulbs and last up to 20 times longer. LED lights are natural beam-formers, which makes it easier to create separate uplink and downlink channels, which essentially means more secure internet browsing. Using LEDs as it has both reduced the light consumption as well as heat dissemination. Besides energy-efficiency of LEDs, there is an added benefit for LiFi cellular deployment in that it can build on existing lighting infrastructures.

Due to its shorter range, Li-Fi is more secure than Wi-Fi. Light's inability to penetrate walls makes it potentially secured. Li-Fi lowers the possibility of external sniff and hacking attempts. The visible light spectrum has 10,000 times more bandwidth than radio waves spectrum. Plus, it’s unlicensed and free to use.

Data can be transmitted over the light spectrum, this makes Li-Fi a form of optical wireless communication. Li-Fi uses infra-red and ultra-violet (visible light) waves to communicate data. Infra-red and ultra-violet spectrums can carry more information than radio frequency waves. This is why Li-Fi can achieve greater speeds than Wi-Fi. Li-fi can deliver internet access 100 times faster than traditional wi-fi, offering speeds of up to 1Gbps (gigabit per second). I also believe that the high speed and the large data density could totally change the way we watch television and also will have great impact on satellite communications.

Benefit of using Li-Fi technology in hospitals, nuclear power plants and aircraft cabins is that it does not cause electromagnetic interference.  Li-Fi technology will allow high data connectivity for each air craft passenger at all times. The reduction in cabling requirement also means a lighter aircraft. It is also used in cellular and underwater communications as light can penetrate for large distances unlike radio waves which get absorbed in water, preventing  underwater radio communications.

Since new generation vehicles are coming with LED headlights and taillights and street lights, signage and traffic lights are switching  to energy-efficient LEDs. So, Li-Fi technology can be easily used for vehicle-to-vehicle and vehicle-to-roadside sensor communications for road safety and traffic management system.

On a larger scale, lasers can be used to transmit high rates of data between satellites in space or to dishes on the ground. Such systems can allow military or telecoms information to pass between two towers or from space to the earth.

Limitations

• A major hurdle is that the connection will be lost if a user leaves the room. To have a continuous Li-Fi network inside our house, we will need  lightbulbs in every room to have seamless connectivity. 
• Another major issue is that Li-Fi does not work outdoors, meaning that public Li-Fi will not be able to replace public Wi-Fi networks any time soon. When it comes to outdoor use-cases, interference from sunlight prevents one from employing Li-Fi solutions.
• Though Li-Fi is not unidirectional, i.e. it can both transmit and receive data, LEDs can currently only be used to transmit data due to feasibility and cost issues involved, as specially designed ASIC receiver or SoC receivers are required for uplink transmission.
• Opaque obstacles on pathways can affect data transmission
• One of the biggest drawbacks of Li-Fi is that it requires light to be switched on all the time to deliver connectivity. 

           Li-Fi technology made its way out of laboratories to live trials in 2015. LiFi is a 5G technology which will unlock the Internet-of-Things and in the future, using light bulb as your wireless hotspot. With faster connectivity and data transmission, Li-Fi  promises to be cheaper and more power efficient than existing wireless technologies. It should be remembered that Li-Fi probably won’t replace Wi-Fi altogether, rather, both the technologies will be used simultaneously for a cleaner, greener, brighter tomorrow.