Invented by Page Larry, founder of Google in ranking web pages, " PageRank works by counting the number and quality of links to a page to determine a rough estimate of how important the website is. The underlying assumption is that more important websites are likely to receive more links from other websites". A page … Continue reading PageRank Factor in Analyzing Company Relationships

From Einstein's time-space equation, people commonly asked if time is reversible. So if that is true, the following equation needs to be true too. Because light of speed is the fastest in the universe, so the right side c*delta t is what light travels, over delta x, must be greater than 1, that infers u/c … Continue reading Fundamental Physics by Ramamurti Shankar at Yale_6_Four Vector

Einstein's famous relativity theory contains two parts - special relativity and general relativity. Let's start from special relativity. Physicists always like to study from simplifying the complex. So here is the coordinate transformation with "me" x and "you" s. However this classical Newtonian transformation is defied by physicists' attempt to measure the speed of light … Continue reading Fundamental Physics by Ramamurti Shankar at Yale_5_Relativity

This chapter is about rotations. Omega - angular velocity is introduced to study this topic. Based on angular velocity, radian is also used to get a quick measurement of the constant value or unit to calculate the circular distance. Professor Shankar list linear and circular motion side by side to help understand the concepts. What's … Continue reading Fundamental Physics by Ramamurti Shankar at Yale_4_Rotations

It's an interesting story about Newton that Professor Shankar mentioned. He published his law of motion and the calculation of Kepler's observation many years later. The reason is that he went on to invent entire integral math to solve the problem pf treating earth as an abstract point or not. This is related to the … Continue reading Fundamental Physics by Ramamurti Shankar at Yale_3_Multi Body System

Wisdom is usually anti-intuitive, that's why we need to study, practice and logically think to attain it. If you refuse to study, and always follow "what your heart tells", you will wander to no where and develop superstition and religion. For example, it's anti-intuition for me to fully understand in circular motion with constant area/angle, … Continue reading Recording Anti-Intuition Wisdom

The second part of his lecture talks about Energy starting with kinetic energy. There are two concepts to understand - power and energy. Energy is deduced from the motion equation in last topic to be K2-K1=F*d, here, F*d is the work that is done, giving energy. it can be measured up by F/Newton and d/Meter, … Continue reading Fundamental Physics by Ramamurti Shankar at Yale_2_Energy Conservation

Learning Newtonian mechanics certainly ordains the math of differentiation and integration, which belongs to the course of calculus. While the concept of differentiation/derivation is relatively easy - we can make sense of it by thinking of the tangent line on a curve point or velocity of a moving object - the mathematical deduction is interesting … Continue reading Fundamental Physics by Ramamurti Shankar at Yale_1_Newtonian Mechanics

What I learn more and more in my life is that most of the time I had been so confused. I am sure there are a lot of confusion at present still, but the good and happy thing I can claim is that I am less confused at this age than before. The reason I … Continue reading Compass in Life

It's not so commonly used in data science, but as an OOP language, Python can make good use of class, object. Unique to Python, there are staticmethod, classmethod, property written by professional programmers. In short, a staticmethod is a method that knows nothing about the class or instance it was called on, while a classmethod … Continue reading Staticmethod, Classmethod and Property