# How can India be poised to become the world’s fastest growing major economy and yet lack funds for almost every major social utility?

How can India be poised to become the world's fastest growing major economy and yet lack funds f… by @DrAwdheshSingh

Imagine that there are two twin brothers named Ram and Shyam.

• Ram has been a very poor student and he has always failed​ in examination. He scored just 10% marks in IXth class.
• Shyam is a good student and he gets good marks in all examinations. He scored 80% marks in IXth class.

Their parents are not happy with the performances of their children and they hired the best teachers to teach them so that they can score well in the Xth board examination.

When the results were announced Ram got 20% marks while Shyam got 96% marks.

The parents are quite unhappy with Ram who failed in examination while quite happy with Shyam who scored 96% marks and got first rank in his school.

Ram challenges his parents and called them biased. Ram argues that he improved 100% in just one year while his brother improved merely by 20% marks. Hence, he claim that he is a better student than Shyam and hence he must get more credit than Shyam.

What do you say for such a logical analysis of Ram?

We often get absolutely wrong picture with improper analysis of data.

British Prime Minister Benjamin Disraeli famously said once: "There are three kinds of lies: lies, damned lies, and statistics."

While India may be the fastest growing economy of the world but India is still far far behind the developed economies.

Reason : Percentages(%) are calculated on a base(per capita income) and that varies with countries.

For example the per capita income of the top countries of the world like Luxembourg ($103,199), Switzerland ($79,242) or United States ($57,436) is more than 30-60 times that of India who per capita income is merely$ 1,723. [1]

Even if these developed countries grow by just 2%, their actual growth is much more than India with even 6-9% growth.

Are you better than Balaji Viswanathan on Quora?

If you use the logic of fastest growing economy in context of Quora, almost 90% of the Quorans would be performing better than the top Quora writer of the world Balaji Vishwanathan.

I can prove it here and now.

• Mr Balaji is adding around 10K-15K followers every month and getting almost 6 Million answer views every month. At present, he has 317K followers and 205 Million answer views.
• Mr. Balaji is thus growing only at the rate of 3–5% in terms of followers and 3–4% over the answer views.
• So, if you have just 10 followers at present 1000 answer views, you surpass Balaji by 100 times by just adding 30 followers and 3K answer views in a month.

If you think that you have become better than Balaji due to this feat, congratulations to you.

However, if you are sane, you know that it becomes far more tough to improve your relative performance as you grow up in the ladder.

India would need several decades of sustained growth to achieve the goals of getting sufficient funds for the social security at par with the developed nations.

Awdhesh Singh

Footnotes

How can India be poised to become the world's fastest growing major economy and yet lack funds for almost every major social utility?

# How was the radius of earth discovered at early time?

How was the radius of earth discovered at early time? by Unnikrishnan Menon

The seemingly impossible feat of measuring the size of the Earth was first accomplished by a genius greek guy named Eratosthenes.

He was born in about 276 BC in Cyrene, in modern-day Libya. Google his name if you wanna know more about him 😛

He spent many years as the Chief Librarian at Alexandria. While at the library, he learned about a Well with a remarkable property…

At noon on $21^{st}$ June each year (the day of the Summer Solstice), the Sun shone directly into the well and illuminated it all the way down to the bottom! This well was situated in Syene. So Eratosthenes deduced that the Sun must be directly overhead on that particular day in Syene. This was something that never happened in Alexandria which was a few hundred kilometers North of Syene! The distance between these $2$ cities was known at that time.

He was aware that the Earth’s curvature was the reason why the Sun could not be overhead at both places simultaneously. Soon he wondered if he could somehow exploit this fact to measure the Circumference of the Earth!

And to do that, he waited for the perfect day, $21^{st}$ June! And the perfect time, $12$ noon!

Click on this image to zoom in.

At exactly the same moment that Sunlight was falling straight down the well at Syene, Eratosthenes stuck a stick vertically on the ground at Alexandria. Then without wasting any time, he immediately measured the angle between the Sun’s rays and the stick. This angle’s measurement blended with the perfect timing was the main ingredient for his recipe to cook up the circumference of our planet!

That’s because this angle is equivalent to the angle between $2$ radial lines drawn from Alexandria and Syene to the Center of the Earth!

He measured this angle between the Sun’s rays and the stick to be $7.2^{o}$

He argued that if the Earth was a sphere, then if he sent a person to walk straight from Syene until he circumnavigates the Earth and returns back to Syene, this person would have traversed a complete circle by covering $360^{o}$

So, if the angle between Alexandria and Syene is only $7.2^{o}$ then the distance between Alexandria and Syene represents $\dfrac{7.2}{360}$ of the Earth’s circumference!

At that time, the distance between Alexandria and Syene was known to be about $785$ km.

So, that simply means, the Circumference of our planet $=\dfrac{360}{7.2}\times 785=50\times 785=\boxed {39250 km}$

And guess what! This value he found out was accurate to $2$%. The reason for this is the fact that the Earth is not a perfect sphere in the first place! It slightly bulges outward at the Equator. I think that’s because of maximum centrifugal force at the Equator due to Earth’s rotation. This teeny-weeny error could also be attributed to…

• Poor angular Measurement
• Error in timing of noon on the day of Summer Solstice
• An error in the distance between Alexandria and Syene

Now that the Circumference of our Planet is know, we can easily find out the Radius as follows…

To make the math a little good-looking, I’ll round it off to $40000$ km

$$$\begin{split}2 \pi R = 40000\\&\implies R = \dfrac{40000}{2\pi}\\&\implies \boxed {R=6350 \text{ km}}\end{split}$$\tag*{}$

The cool thing is that all we need to Measure the Size of our Planet is just a stick and a man with a brain 🙂

PS: Ignore my drawing skills on MS Paint 😛

How was the radius of earth discovered at early time?

# Have you ever seen a student roast a teacher?

Have you ever seen a student roast a teacher? by Tan Peng An

There was this guy in my school (we were 17 and were in arguably the best school in the country) who used to sleep through every class he took. At first, all the teachers ignored him but one particular math teacher got pissed and decided to make an “example” of him.

She prepared a very difficult math question (dont forget Singapore topped the PISA international math exams so difficult means really difficult and way above our syllabus level) and wrote it on the board, then asked the person next to him to wake him up to answer the question.

*Not the actual guy

The sleepy guy yawned and then took a look at the board. He kept still and quiet for 10 seconds and the teacher started to go into a lecture about paying attention in class blah blah blah….when the guy interrupted and just stated the answer without working out anything on paper. The teacher (who herself was a top scholar and had an advanced math degree from MIT) was FLABBERGASTED as she expected a brillant person to have needed at least 1/2 a page of calculations to arrive at the answer…

She recovered quickly and she then asked the sleepy guy if he had any questions on classwork. BIG MISTAKE….the sleepy guy had a question and walked up to the board, wrote a question down and said he had trouble solving the equation. The whole class was so quiet you could hear a pin drop…Needless to say, 45 minutes later, the teacher had still not managed to solve the equation.

PRICELESS!

After extensive tests covering numerous math topics, the sleepy guy was then given a dispensation by the school for all math classes during his time there – he eventually got a full scholarship to Princeton…

Have you ever seen a student roast a teacher?

# What is your favorite coding project you have done?

What is your favorite coding project you have done? by @Ragav_G

My Favorite is building the Person of Interest machine 😉

In my sophomore, I came across the CBS series “Person Of Interest” that revolves around a computer system dubbed the “Machine” that can analyze data from surveillance cameras, electronic communications, and audio input and predict acts of crime.

I had this spark then in 2013, Why can’t I make one such machine? While most of the things the machine do are fairly impossible at present, I was able to design a working system of the machine that can perform at least half of what the POI Machine does.

The “Machine” as described in Person of Interest has artificial consciousness which is pretty much out of equation at the current moment. I started listing down all the features the machine came packed with, thanks to the episode where Nathan boots the system reveals most of the stuff.

The first step was to decide upon the technologies I need to use, and I ended up with the following,

1. NodeJS for forwarding and handling the videos streamed from the users’ webcam through Websockets
2. Python for most of the NLP tasks, OCR, Information Extraction, Anomaly detection,etc,.
3. C++ for processing the images from videos using OpenCV
4. Databases including MongoDB, Redis, MySQL, Cayley.

Various other frameworks and libraries used includes NuPIC, OpenCog, ConceptNet, Natural, WordNet, Freebase and DBPedia. And of course, Apache Hadoop and Thrift.

Once I had decided on all the technologies to work on, I started building it. The initial phase was to ‘teach’ as in POI terms to recognize faces of people, their speech and analyze their emotions.

I tested it in a closed environment, in my room, myself at different corners checking if it can see me and followed the test with multiple users. Once it was able to do so, the next problem as Harold says would be “to sort them all out”.

The system needs to have knowledge of the world. I made use of ConceptNet and WordNet to serve this purpose. For the sentiment analysis from users’ speech, I used AFINN list and it turned out to be very good one.

The Query processing was a tedious job. I referenced the architecture of IBM’s Watson (It’s one hell of a Q&A System).

Graph Database plays a vital role in mapping the connections between the users in real world. I can recall an episode where the machine points out that “the taxi driver and the passenger were actually fifth cousins”.

I was initially skeptical on opting for the right one, but ended up finally with Cayley and it did the job pretty well.

Handling the data was a very difficult task. Most of the information you receive will be unstructured and thanks to UIMA, I was able to sort out most of them.

The system used a small Memcached instance to cache the primary information of all the people included an uniqueID, names, Aadhar ID (like SSN), their recent location, emotion and seen with, when. The last four tend to change in real-time (or, near maybe).

I didn't want the ‘machine’ to be neither a closed or open system, but a combination of both. The machine works autonomously, and it will send you an email when you are predicted to be a victim.

When I mentioned the system to be a ‘combination of both’, it comes with an UI where you can query a name or Aadhar ID and the machine will say only where the person was, when and with whom. Nothing more than it as it may pose a threat to their privacy.

It cannot actually identify a gun shot, but did a good job on predicting the crime from speech, and their emotions. I did also patched the system to identify the person with a colored box as seen in POI, “Yellow” for who knows about the machine, “White” for common people and “Red” for perpetrator.

The cluster configuration on which it ran is as follows,

1. 5 nodes each with 2.1GHz Intel Quad Core processor and 4GB RAM
2. 2TB of total memory
3. Each equipped with a NVIDIA GeForce GT 610 GPU

The system achieved a maximum speed of 0.29 Tflops, which is really not great, but fair enough initially.

DAY 1

I was pretty excited. It has been technically Day 0 in those earlier days of building. Booted the system and started with small face and speech recognition tests. It did good on tracking a couple of people but failed when scaled up. It was a triumph to me and I was jubilant, I forgot to take images on Day 1.

To put it in action, I connected it to my department’s local network and subscribed to the video stream from the computers (well not legal). I can still recall my friend saying to the other during demonstration “We must kill Raghav before this weekend at the central park”.

I got an email within seconds notifying me that I am predicted to be a victim.

Now I needed to test the system in Real World. Thanks to my College, we have over 13 CCTV equipped round our campus and our lab being the relay to the network, I was able to tap into the network and woila, I had this,

As days progressed, I improved with features like it calling me through Twilio and also revamped the UI to suit Samaritan,

Apparently my friends weren’t aware its running on their system too.

Its been 2 years since I ran it and it is quietly resting inside my backup HDD.

Edit: Digged up some of the old pics,

I needed a medium through which the machine can communicate with me on the go. Facebook didn’t have its Bots API earlier then, so I created a separate account for the machine, and integrated Facebook API that allowed it to chat with me from anywhere,

I also made a Dashboard through which I was able to view the locations of the people the system tracks, their devices connected to network within our campus network,

Finally, When I upgraded the system to the new UI and wiped all memory (Day 0)

Along with my friend, we were able to build a portable version of the system that is solar powered and can be fitted anywhere like lamp posts. The main goal of the portable version was to provide assistance during Disasters where the Government can remotely access affected areas, find casualties, provide charging station for smartphones and also WiFi hotspot for nearby people by connecting to Outernet. We showcased the system at a Nascomm’s event,

Edit #2: While I am overwhelmed by a lot of positive response, I came across a few comments questioning the authenticity of the answer above and I would be very much happy to share some things,

I had posted the above answer in my personal medium blog late Nov 2014 (How I built the Person of Interest Machine – Raghav – Medium) and suprisingly I was curious enough to share the first day I started working on this thing in Twitter in Nov 2013

I made the revamped UI and the dashboard to track the people at Freshdesk’s Save the Hacker hackathon in May 2015,

You can see the video stream along with the data in the Browser client and Yes, it is streamed in real-time through Websockets and the information are drawn over them using HTML Canvas. You can see a similar project opensourced here (drejkim/face-detection-node-opencv) and I didn’t clone this repo as base one (you can see it was done on Dec 2014) whereas I shared my first day tweet on Nov 2013. I would highly suggest the above repo for people who want to know how the server works seamlessly with OpenCV and streams the frames in real-time to the Browser.

I had also received a lot of comments on Open-sourcing the system so that people can look over and collaborate on building. While I would be happy to do so, I believe the system is too early to be open sourced and it is my long term vision to put this project in real-world use. Meanwhile, I will opensource individual components that I had built including the Anamoly detection, Knowledge Graph, etc,. eventually in my GitHub.

What is your favorite coding project you have done?

# What are the basic math skills that everyone should know?

What are the basic math skills that everyone should know? by Nipun Ramakrishnan

In the heat of World War II, a lot of American planes were coming back riddled with bullet holes. One of the interesting things about this situation was that the bullet holes were concentrated in different regions of the plane. Some planes came back with bullet holes in the engine, some in the fuselage, etc.

The military saw an opportunity for efficiency. They realized that if they could focus on fortifying the areas of the plane that were the most prone to being hit and seriously damaged, they could not only save more planes, but also save on the amount of armor they use. The military came to Abraham Wald and a few other leading statistical researchers with the following data on the surviving planes and where the bullet holes were concentrated:

Based on this data, which part of the plane do you think the military should fortify?

Most people would answer that it should be the fuselage, and they would be wrong.

The more accurate answer is the engine. Wald insightfully realized that the data that he had been given was not an appropriate representation of the problem. The reason that there were fewer hits on the engine is that the planes that got hit in the engine were not coming back. And the fact that a majority of the surviving planes had bullet holes in the fuselage is pretty strong evidence that the planes could tolerate damage to the fuselage.

Wald realized that there were only two explanations for the data:

1. Bullets just happened to hit every other part of the plane more often than it hit the engine
2. The engine is a point of vulnerability

And it doesn’t take a genius to see that the second explanation is a lot more reasonable than the first and after the Wald’s recommendations were put into effect, a lot more American planes were saved.

One of the most underrated mathematical skills is the ability to understand the underlying assumptions made by data. Abraham Wald was able to solve this problem because he realized the military made the assumption that the data represented all planes rather than just the surviving planes. A lot of the statistics that are thrown out in the world today tend to fool a lot of people into believing what they want to hear, but how you separate the facts from the bullshit is by understanding the assumptions made by the data.

If you want to see more of these types of examples, I highly recommend Jordan Ellenberg’s How Not to Be Wrong: The Power of Mathematical Thinking which does a great job explaining the Wald example as well as many other examples in which forgetting about the assumptions behind the data can lead to ridiculous conclusions.

What are the basic math skills that everyone should know?

# What are the most productive ways to spend time on the Internet?

What are the most productive ways to spend time on the Internet? by @devpersonality

Most Productive ways to spend time on Internet

Having a Internet connection opens you to large depository of knowledge. You might not completely aware of the power that Internet gives you. Thanks to smartphones, Virtually, we have unlimited source of information at our fingertips.
There are numerous websites on the internet that can make you smarter and more intelligent at no cost. Of Course, there are websites which can distract, you but if you want to utilize your time on the Internet, here is the list of sites that you must consider.

1.Quora.com : You Are Already Here. 1st Level Completed !!

2. Duolingo.com: 2nd Level !! Yet to Complete..

An awesome language teaching site that teaches you some International Languages from scratch. Currently it supports only Spanish, French, Italian, German, Portuguese and Dutch, but more will be added soon. The good thing about the site is it starts at beginner level and it is completely free. If you put little effort and are really interesting in learning a new language, in couple of months you can speak and write a new language. Learning with duolingo is fun and addictive. Duolingo app is available for both iOS and Android so that you can learn anytime.

3. Lumosity.com, Must Have Completed !!

An online application to test your brain and achieve its full potential. It provides free brain testing, memory testing and logical reasoning exercises which refreshes your brain and makes you more smarter and sharper. It’s the web most popular scientifically designed training program.

This site deserves a much higher place in this list because of its mission which aims at providing world class education to those who need it but cannot afford it. It is non-profit organization which provides world class education for everyone everywhere free of cost. It covers a wide variety of subjects like mathematics, science, economics, Arts and humanities and computer science. It also provide lectures for various test preparation like SAT, GMAT,IIT-JEE, MCAT, etc.

All the Khan academy’s educational content and material is available to everyone completely free of charge.

5. Ted.com, Who doesn’t know about it.

Collection of TED (Technology, Education and Design) talks in which experts addresses on wide variety of useful topics through small interval videos. It is like attending a world class seminar from home.

Do you ever dream of studying at world’s top universities? Now you can virtually fulfill this dream. Coursera.com provides online courses in collaboration with world’s best universities like University of California, The Hong Kong University of science and technology, Stanford University, University of Pittsburgh, University of Tokyo, University of Michigan and many more.

The approach used by coursera.com is very much similar to real classes. You learn by watching demonstrating videos, perform activities and assignment and then submit the assignments .On the basis of your assignments you get marks. The quality of content and material at this class matches the education quality at world level universities. Here are the some courses I am currently attending :

All these courses are available free of cost.

An ultimate site that helps stay in shape and provide valuable health tips. It provides very valuable information and case studies on how you can lose your weight. Feel like getting instructions from a professional sitting at home.

As Internet is expanding each day, there is more demand of web developers and programmers. At codecademy you can learn the basics of code. You may not become a professional programmer immediately after following the tutorials but this site teaches you the right way to become an expert. Currently it provides classes and courses on web technologies like HTMLHTML, Javascript , jQuery, PHP, Ruby, WordPress, etc.

This site can be considered the repository of free online educational resources which include videos, tutorials, eBooks and audio books. It does not provide educational content itself but collects all the good learning material from all the sites(including the sites I mentioned above) and collaborate them so that you can access them at single place.

A unique site which provides information about the major facts of all countries. Select a country either alphabetically or from map and access information like Geography, People, Military, Communication, currency, Economy and so on.

A huge community which provide how-to-do step by step guides on almost everything – from some basic household tricks to high end tech tricks.

If your hobby includes reading and you are curious about things, then this is the site for you to visit. How Stuff works – An online source of easy to understand explanations

of how certain things actually works. From car engines to search engines, from cell phones to stem cells, and thousands of subjects in between, HowStuffWorks has it covered.

Thanks to Sambhav Jain for suggesting it.

The list of such kind of websites is very long. I tried to cover only those which I found highly productive and useful. Do I Missed a great online resource? Share it with us by commenting below.

Edit : Thanks To All For 2.5K+ UpVotes!!

Cheers!!

Some of my other famous Answers!!

Ritul Mishra's answer to What is the most clever life hack you've learned?

Ritul Mishra's answer to What are best tricks you know and you want to share?

Ritul Mishra's answer to What should everybody know?

Ritul @ Author of the Post that got 1.7K shares (As On 02/06/2017)!— Thanks to all the Quorans!!—29 Things that can Make you Lead a Successful, Healthy and Happy Life! – PersonalityDev

What are the most productive ways to spend time on the Internet?