Saturday, March 28, 2015

edX: - HarvardX: CS50x3 Introduction to Computer Science - week 0



  • Computers only understand zeroes and ones, an alphabet called binary. While humans use decimal, which has 10 digits 0-9, computers only understand binary, which has two digits, 0 and 1.
  • Now we can do more, by using ASCII, a standard that maps numbers to letters. For example, A is mapped to 65B is 66, etc. Though bits can only store numbers, programs can translate those bits to letters for humans to easily read.

Algorithms


  • Algorithms are sets of instructions to solve particular problems, taking inputs and producing outputs that are hopefully correct, but also efficient.
The famous phone book example:
  • We can open to the first page, and look for someone, say, Mike Smith. Then we continue to the second, third, and so on until we find Mike Smith. That algorithm is correct because we will find him eventually, but isn’t very fast.
  • Humans reasonably open to the middle, and since the phone book is alphabetical and the middle is the M section, we can literally tear this problem in half by ripping the phone book in half and keeping only the half that we think Mike Smith is in. 
efficiency

  • The green line will have a logarithmic slope that doesn’t increase in height as much as the other lines. With the phone book, even if the size of the phone book doubled, it would only take one more step to solve the problem.

Pseudocode is describing code for a problem in English:


1pick up phone book 2open to middle of phone book 3look at names 4if "Smith" is among names 5 call Mike 6else if "Smith" is earlier in book 7 open to middle of left half of book 8 go to line 3 9else if "Smith" is later in book 10 open to middle of right half of book 11 go to line 3 12else 13 give up


Saturday, March 21, 2015

Roberta Flack- "One Thing Leads to Another"

This is one of the most underrated songs of the eighties. It was featured  in the movie "Body Rock" which I did not think was that bad either.

Saturday, March 14, 2015

Coursera:- Learning How to Learn: Powerful mental tools to help you master tough subjects

This is a more self paced course at Coursera. I have only watched the first video  and it seems ok so far. I don't really know what the rest is like  but I presume it will give more ideas on how to be a better learner.

https://www.coursera.org/learn/learning-how-to-learn

Thursday, March 12, 2015

Finally managed to access Cousera

I finally managed to access into Cousera website after trying for some time.  I have enrolled for an electronics course (actually the course has not started yet)- https://www.coursera.org/course/introtoelectronics -  from Georgia Institute of Technology   Before that it was hard to get into the website and if it did, courses were slow to search.

It has almost the same system as edX in terms of awarding the certs but it does not have the Xseries kind of certs.

Wednesday, March 11, 2015

How to Calculate Hamming Distance

I couldn't quite understand what was from edX  on Computation Structures about this topic  so I google searched a bit and came out with this

http://classroom.synonym.com/calculate-hamming-distance-2656.html

Still I have learnt quite a bit so far from the courses at edX.  I am also trying out the Discrete Time Signals course from Rice University   which seems to be a bit more comprehensible so far. Update: apart from the Hamming distance, the MIT course has been quite comprehensive so far.

Monday, March 9, 2015

"Alone Yet Not Alone"- Joni Eareckson Tada

This song is featured in the movie Alone Yet Not Alone (2013) which created some controversy over its nomination in the Oscars. It was eventually removed from the nominations  but really the song itself is worth listening.

How to remove / repair broken RCA male pin from female socket when snapped off inside

It seemed like an impossible task at first but I managed to do it after watching this  video.




I used a safety pin and and kitchen lighter -  it worked too.