A Great Place for Free Online Learning - Coursera

Coursera is a great place for online learning. This has subjects varying from Computer Science to History , Sociology, Medicine and Music. All the subjects are offered from the top ranked Universities in the world. Currently there are 16 Universities affiliated with Coursera and this includes MIT, CIT , Stanford University and Princeton University.

Some available courses 

The courses offered are well organized. Around 5-12 hours per week are required to complete a course and the duration of the course will be 6-16 weeks. Almost all the courses includes weekly lectures which have a duration of around 10-20 minutes. There will be several lectures per week adding up to 2 hours per week. Also there may be weekly quizzes, assignments or programming assignment depending on the course. Quizzes will either MCQ or short answers which will be evaluated automatically. Assignments are normally peer reviewed. Also most of the courses have an end exam and mid exams.After the completion of the course participants will receive a certificate if they have performed well in exams and assignments. But this certificate will not be considered as an official certificate offered by the relevant University.

Coursera is started by Andrew Ng, an Associate Professor in the Department of Computer Science at Stanford University, and Director of the Stanford Artificial Intelligence Lab and Daphne Koller a Professor in the Department of Computer Science at Stanford University . Although this was started in this year it has many partners. Currently all the courses are free and the business model is not finalized. It is expected that it will be something about selling the information about participants to potential employees and offering of certificates.

Currently Coursera offers more than 100 different subjects. The number of enrollments per subject some times exceeds 100k. These courses will give a very good chance to learn some thing new in a very organized manner. The quality of the courses are very high and it is very good chance to experience the future of e-learning. This will be a very good opportunity to gather international quality knowledge freely.Visit the Coursera web site from the following link.


https://www.coursera.org/

Hotspot Technology

One of the main technology used in Umpire Decision Review System (UDRS) in cricket is the Hawk-Eye technology which tracks and predicts the path of the ball. Other main technology which is not mandatory under current cricketing laws is the Hot Spot technology. Hot Spot is the best available technology to establish the contact between the ball and the bat or pad.

History

Australia's Nine Networks owns this technology

Interestingly hot-spot technology was not intended to be used in cricket initially. It was expected to be used in military applications. These includes tracking jet-fighters,warships, tanks and satellites.This technology was founded by french scientist Nicholas Bion and later developed by other companies in paris. The Australian Nine Networks bought and adopted this technology. This technology is now offered by BBG Sports,an Australian company responsible for Snickometer in conjunction with Sky Sports.This technology was first used in the first ashes test match at the Gabba on 23 November 2006. The first usage of Hot Spot in the decision making process in cricket was in 2009 in South Africa.

Technology

Hot Spot uses infra-red cameras to capture images. There will be either two or four cameras at each ends of the ground. These cameras sense and measure the heat.When a collision happens either between bat and ball,bat and pad,pad and ball or ground and ball the temperature of those areas will be increased.Thus collided areas will be shown with a different color.

Advantages

Hot Spot has considerable advantages than other technologies used in Decision Review System.Hawk Eye is only used to predict the path of the ball.The only other technology available to detect collisions with the bat or pad is Snickometer or a very slow motion camera replay. But it only gives an idea about the time the collision happened and its amplitude. Thus no information about the point of contact can be obtained from Snickometer. But Hot Spot cameras gives the exact point of contact of the ball with the bat or pad. Thus Hot Spot is the best available technology to detect whether the ball hit the bat or the pad.

Disadvantages

The main disadvantage of this technology is its high cost. The cost of two camera set up is around 5000$ per day for two cameras. So if four cameras are used for a test match total price add up to 50000$. This is a huge amount of money and if we consider the limitation of number of reviews per innings for a team (which is currently two incorrect reviews) this cost can not be justified. Even when hawk-eye and other technologies were available at a much lower price some cricket boards still can not afford them due to financial reasons.

Also the number of Hot Spot cameras available are limited. These cameras are classified as a military device and needs a temporary export license from Australian Defense Department when used in another country. Also there are other government regulations that need to be satisfied.
Due to above reasons the usage of Hot Spot in Umpire Decision Review System is not mandatory.This technology was not used even in the ICC Cricket World Cup 2011.

Controversies

Although the inventors of Hot Spot claims very high accuracy, some of the decisions involving this technology have been controversial. There have been instances where Snickometer and other technologies confirms that there is a nick but ultimately Hot Spot did not show any evidence. Also during a test match between India and England there was a confident appeal for a caught behind. Although replays suggests that there may be some bat involved Hot Spot technology failed show any edges. Later Michael Vaughan tweeted that Laxman may have used Vaseline in his bat thus making it impossible to detect edges using Hot Spot technology.

Due to this criticism the inventors of hot spot technology carried out more tests on the reliability of the technology and now they have improved there technology and thus the accuracy of the system. Also they have proved that applying Vaseline or any other substance on the bat can not manipulate this technology. 

With new improvements this technology will be very useful for a fair game of cricket.But the problems with the cost and the unavailability of the devices have limited the usage of this in most cricket matches. Unless the price of this technology is reduced and the number of cameras available are increased this will not be part of the mandatory technologies needed in Umpire Decision Review System (UDRS).

VJD System - Alternative to the Duckworth-Lewis Method

Although the Duckworth-Lewis method is widely used in international and first class level there are many criticisms about this method.One of the main criticism about the DL method is that it gives a higher weight to number of wickets remaining rather than number of overs left. As an example DL par score jumped from 117 to 140 at the end of 20 overs when West Indies lose there 4th wicket in the 20th over at the recently concluded first ODI match between England and West Indies.WI were 1 run ahead before the wicket and suddenly 23 runs behind the target after the wicket.Thus it is very important to a chasing side, not to lose wickets rather than maintaining the required run rate.


Another problem with the DL method is it's inability to handle the power play overs.There is no way to account for the number of power play overs left and number of power play overs played. Also since it uses a G50 score concept where the average score was considered as 250 for an ODI match ,the target scores obtained by DL method was not very justifiable for very low scores and and for very high scores. Thus the effectiveness of the Duckworth-Lewis method is limited to a range of scores distributed around 250. Although this error was corrected for a certain extent in the professional edition still the Duckworth-Lewis method is not that accurate in lower scores and higher scores.

Duckworth-Lewis Curves

Also when multiple interruptions happens the targets given by the Duckworth-Lewis have many anomalies.  The target given by the Duckworth-Lewis method when the interruption happens during an innings break clearly favors the chasing side if the first innings score is high.This is because they have all the ten wickets in hand at the start and the number of overs are reduced. Due to this fact these days captains choose to field when they win the toss if rain is expected during the match.


Also Duckworth-Lewis method was originally designed for ODI matches. Thus when this was used in T20 matches it gives inefficient and unfair results. This may be because the lack of data to construct the resource curves for T20matches. In-fact the unsuitability of the Duckworth-Lewis method in T20 is the main criticism against it.

V. Jayadevan

Thus the need of a new system to be used in rain affected matches have been raised. The main competitor that has challenged the Duckworth-Lewis method is V. Jayadevan method which is used in Indian domestic matches. This is widely known as VJD method.


The designer of this method V. Jayadevan is currently working as an Engineer, Irrigation Department, Kerala. He has spent fifteen years to develop VJD system which is used for calculating revised target due to interruptions in ODI & T20 cricket matches, as an alternative to the existing D/L system.




Previous posts on Duckworth-Lewis method.

1. Duckworth-Lewis Method (part 1)
2. Duckworth-Lewis Method (part 2)
3. Duckworth-Lewis Method (part 3)

Transit of Venus

The last Venus transit for this century will be visible to Sri Lanka Tomorrow (June 6th). This will be a great opportunity to us.Following details may help to observe the transit safely and correctly.

Viewing Safely

It is very important to use the safety procedures while observing the transit.Inappropriate viewing methods may result in blindness and other eye problems. Following link contains some safe viewing methods.

http://sunearthday.nasa.gov/2012/transit/viewing.php

http://www.transitofvenus.org/june2012/eye-safety

 

Useful Links

• NASA - http://sunearthday.nasa.gov/2012/transit/index.php

• Transit of Venus - http://www.transitofvenus.org/

• Wikipeadia -  http://en.wikipedia.org/wiki/Transit_of_Venus,_2012

• Webcasts -  http://www.livescience.com/20747-venus-transit-webcasts-watch-live.html

The Hawk Eye Technology

Technology has become an integral part of our lives. The use of technology in sports have also been increased. At first it was about broadcasting events worlwide.  But in the modern times technology is used to increase the fare-play in sports. Cricket has been one of the sports that uses technology extensively.  The first instance of using technology in cricket may be the third umpire concept which was first used in a test match in 1992. Although it was just a simple TV replay it helps a lot to take correct decisions on run outs and stumping and sometimes the legality of catches and to decide about boundaries.

But within the last few years more sophisticated technologies have been emerged and they are now been used in the game of cricket. One such technology is the hawk eye technology which is used in UDRS (Umpire Decision Review System).

History

Dr.Paul Hawkins

Hawk-Eye is a ball tracking system which is also used in other sports such as tennis. This technology is controlled by the Hawk-Eye Innovations Ltd which is a part of Sony Europe. Initially this was used as a broadcasting tool in cricket LBW decisions and now has become an important part in the decision making process in cricket matches.

The initial research for the Hawk-Eye technology began in 1999 by Dr.Paul Hawkins at Roke Manor Research Ltd. In the year 2001 channel 4 used this technology in broadcasting the Ashes series. In February 2002 this technology was first used in tennis broadcasting. In 2005 Hawk-Eye was permitted to be used as an officiating aid in tennis. This is mainly used to detect the line-calling decisions. In 2007 MCC world cricket committee announces that the Hawk-Eye will be used in the Decision Review System used in cricket.   In 2011 Hawk-Eye was used in a Cricket World Cup for the first time in history. Also there are plans to use Hawk-Eye in Soccer. This is still at the testing stages of FIFA and if the results are successful, this will be used in 2014 world cup.

Technology

Camera Placement in Tennis

The Hawk-Eye uses six high speed vision processing cameras positioned at different places in the ground along with two broadcast cameras to calculate the trajectory of the ball. Although there are 8 cameras available only 5 cameras are used depending on the side of the wicket that’s been used. In tennis there are around 10 cameras to track the ball. These cameras obtain a 3D visualization of the path of the ball after it’s been bowled. There will be two trajectories for each ball one for releasing the ball by the bowler up to pitching and another one for pitching the ball up to hitting the batsmen. Using this technology the speed of the ball, the swing of the ball from the bowler’s hand to the pitching point, the pitching point, the bounce of the ball, the spin or deviation of the ball can be obtained. Based on the second trajectory the expected path of the ball will be calculated and used to determine whether it will hit the stumps. This is widely used to decide LBW decisions.

Controversies

Camera Placement in Cricket

When technology is used in a sport there will be three very important things to consider. First it should be accurate. Then it should be fast enough so that the momentum of the game is not lost due to technology and finally it should be economically and technically affordable to use in normal games.

Hawk-eye is financially feasible. It is a low cost solution which only needs several cameras and some computers to do the calculation. Since cameras will be always available in an international sporting event the installing cost is very low. Also the time taken to calculate the path of the ball is short but sometimes this may damage the momentum of the game. This is one reason that the number of challenges by the players against the normal decisions taken by umpires or referees is limited. In cricket this is two reviews per team in each inning. Also in tennis the player will get two incorrect challenges per and three challenges in a tie break.

But the problem with the Hawk-eye is its accuracy. Although in tennis they have proved that it has an accuracy of 3.6mm in line calling decisions Hawk-Eye has failed to obtain the trust among players, referees and the general public. Also there are few instances in cricket that the decision given by the hawk-eye system is different than what most of the people expected.

Words are all I have, to take your heart away - Bee Gees

Bee Gee legend Robin dies

Robin Hugh Gibb (22 December 1949 – 20 May 2012) was a British singer and songwriter. He is best known as a member of the Bee Gees, co-founded with his twin brother Maurice and older brother Barry. He had another younger brother, Andy Gibb, who was also a very popular solo singer.

Below is one of my favorite songs.This is a song by the Bee Gees, written by Barry, Robin and Maurice Gibb. Barry said in 1996 on the VH1 Storytellers television show that it was written for their manager Robert Stigwood.

Smile an everlasting smile, 

a smile can bring you near to me. 

Don't ever let me find you down, 

cause that would bring a tear to me. 

This world has lost its glory, 

let's start a brand new story now, my love. 

Right now, there'll be no other time 

and I can show you how, my love. 

Talk in everlasting words, 

and dedicate them all to me. 

And I will give you all my life, 

I'm here if you should call to me. 

You think that I don't even mean 

a single word I say. 

It's only words, 

and words are all I have, to take your heart away. 

Some Chuck Norris Facts- Explains Many Things

• Chuck Norris' tears cure cancer. Too bad he has never cried. 
• Chuck Norris has already been to Mars; that's why there are no signs of life there. 
• The Great Wall of China was originally created to keep Chuck Norris out. It failed miserably. 
• When Alexander Bell invented the telephone he had 3 missed calls from Chuck Norris 
• Chuck Norris counted to infinity - twice. 
• Chuck Norris wakes up his alarm clock 
• Chuck Norris doesn't call the wrong number. You answer the wrong phone. 
• There used to be a street named after Chuck Norris, but it was changed because nobody crosses Chuck Norris and lives. 
• Some magicians can walk on water, Chuck Norris can swim through land. 
• Chuck Norris remembers the future. 
• Chuck Norris and Superman once fought each other on a bet. The loser had to start wearing his underwear on the outside of his pants. 
• Chuck Norris will never have a heart attack. His heart isn't nearly foolish enough to attack him. 
• Chuck Norris received his pilots license by just looking at an airplane. 
• Chuck Norris does not hunt because the word hunting infers the probability of failure. Chuck Norris goes killing. 
• Chuck Norris called 911 to order Chinese food and got it. 
• Only Chuck Norris can dislike on Facebook 
• Chuck Norris uses a sundial at night. 
• When Chuck Norris looks at himself at a mirror, there is no reflection. There can only be one Chuck Norris. 
• Contrary to popular belief, Chuck Norris cannot fly. He just jumps and chooses when to come down.