Mohamed Mohab Blog

President Obama speek 11-February-2011

2011-02-12T14:18:00.006+02:00

President Obama was just commenting on what happened in Egypt!

For us we see him just repeating what we have been already hearing from our media and actually seeing with our eyes. But we can see him felt the responsibility to show the world that we are a civilized and peaceful nation.

I could say that international media was transferring other pictures from Egypt despite Pyramids, temples, monuments, Camels and Sharm el-sheikh. We are a country that dates back to 6 thousand year but we aren't old.

I invite you to be here in Egypt not right now, but in a couple of months to see Egypt. Not just to see the pyramids, but also to see our civilization and hospitality. You will be safe and even safer, will you come?

bibalex new DAR site

2010-10-29T23:32:00.001+02:00

I have been working for a while in Bibalex digital book new site, here is a sample embedded book from the new site.

The book site provides users with online access to bibalex out of copyright books as well as a limited preview of copyrighted books.

You can sign up and enjoy new features like annotation tools which includes highlighting text, underlining text and adding stick notes in a certain position in a book.

the release version of the site is http://dar.bibalex.org/

Computer aided poetry

2008-09-30T19:12:00.000+02:00

Computer aided poetry

For many years computers have been used to perform complex computations and make visual simulations and even think in an intelligent way. Can computers write text and poetry like humans?

The approach to let software produce text is either by synthesizing text or poetry from pre-existing text. Other approach is by using dictionaries and rules for sentence construction.. Either way, the use of the computer to generate texts challenges the very nature of the text and the role of the author. But the texts in themselves can also be beautiful.

A program called MarkV can produce text from a collection of some poetry fragments, here is some output:

He was a light, slow, and there is a small Saturn -- away from a high flame lying in the life within it, a new dune, we are formations of caterpillars, we are formations of craziness to innocent, and as it moves it is complete different than the rising face, the cold water, even we can't see infinity is an ocean of downy treasure the welldeep pleasure of caterpillars, we are formations of the world, and what it with the ecstasy of the day is an iceberg we find ourselves on a caress mingled with sleep kill me its lights bands of subjective experience, and wonder why I had dirt a star-crystal-flower plants, made the dragon. Its neck was a novel entitled "Kaleidoscope Vision," which is hat crinkle were like fresh glass domain key - you become someone mentioned them and build in. We see the white my own rising and thunder clapping in the singularity of it, evaporating into a tree, like a long before shade. electricity continues all languages are swept in spirals, in the coming moment

jpoetry poetry generator
http://www-cs-students.stanford.edu/~esincoff/poetry/jpoetry.html
Heretical Rhyme Generator
http://www.pangloss.com/seidel/Poem/

Calculating Muslims' Prayers Times

2008-01-23T14:08:00.000+02:00

Calculating Muslims' Prayers Times

I thought how to mathematically compute prayer times? Then I found that calculations of prayers times are more complex than I imagined.

Do you think that Douhr at 1 JAN 2005 is at the same time of 1 JAN 2008 for the same location?
Do you think that prayer times are the same for locations of the same longitude for the same date?
Are there any parameters other than date and location that could be taken into account when calculating prayers times?
What about prayers times for locations near poles where day can be as long as months?

Let's start by Douhr:

Douhr starts after midday. Computation of Douhr time depends on the location and the date:

L is longitude of the location in degrees.
EQT is equation of time.
Z is Douhr time in hours.

Since Time zone and L are constant over time i.e. depends only on location, the only time varying element is EQT equation of time which is defined as the difference between Local Apparent Time and Mean Solar Time in minutes. Time measured from sundial is the Local Apparent time while Mean Solar time is that of a clock. This difference arose from the fact that the earth's orbit around sun isn't a circle, but an ellipse. Other reason is the angle of obliquity which is the angle between that the plane of the Equator and the plane of the Earth's orbit around the sun.

Variation of EQT over the year

You can notice that there are 4 days of zero EQT Apr 15, Jun 14, Sep 2 and Dec 25.

Accurate calculation of EQT depends on the Julian day which a count of days since Jan 1 4713 BC. Some EQT graphs are inverted, simply add EQT to equation of Z instead of subtraction.

A good approximation of Equation of time:

EQT = 229.18*(0.000075+0.001868*cos(rads) - 0.032077*sin(rads) - 0.014615*cos(2*rads) - 0.040849*sin(2*rads))

This computation depends only on the day of year thus it's accurate only near 2005.

Fajr and Isha:

Fajr and Isha depend on Duhr as follows:

Fajr = Duhr – Tw(Ө)
Isha = Duhr + Tw(Ө)
Tw(Ө) is the period from noon till a twilight angle Ө.

Twilight: earth's atmosphere scatters sun light. In the absence of atmosphere on earth there would be no sunlight after sunset and before sunrise. So, Twilight causes gradual decrease of sunlight.
Twilight angle is the angle between line reaching sun's center and the horizon. Sun's center must be below it.

Greater twilight angle leads to earlier Fajr and later Isha.

This table represents conventions used to choose twilight angle

Convention	Fajr Angle	Isha Angle
Leva Research Institute, Qom, Iran	16	14
University of Islamic Sciences, Karachi	18	18
Islamic Society of North America (ISNA), USA	15	15
Muslim World League (MWL)	18	17
Umm al-Qura, Makkah, Saudi Arabia	19	90 mins after Maghrib
Egyptian General Authority of Survey	19.5	17.5

To imagine twilight go to seaside at sunset and observe the sun gradually disappears , when you see the center of the sun at the horizon level , then the twilight angle is just near 0. Now the sun disappears and still sunlight is observable, that's twilight. Twilight ends when no sunlight is seen. The same can be done at sunrise.

Twilight before sunrise

Tw(Ө) is the period from noon till a twilight angle Ө:

Where lat is latitude of the position.
D is declination angle.

Calculation of D depends on location and Julian date.
Other approximation for Declination angle is:

D = 0.006918 - 0.399912*cos(rads) + 0.070257*sin(rads) - 0.006758*cos(2*rads) + 0.000907*sin(2*rads) - 0.002697*cos(3*rads) + 0.00148*sin(3*rads)

Variation of declination angle over the year

Sunrise (Shrook) and Sunset (Maghrib):

Similar to Fajr and Isha but with twilight angle of 0.8333.

Sunrise = Duhr – Tw(0.8333)
Sunset = Duhr + Tw(0.8333)

Sometimes more accurate measures can be obtained by taking into account height above sea level.

Where H is height above sea level in meters.

Asr:

According to Shafii, Hanbaly and Maliky mathab Asr starts when the length of an object's shadow equals the its length plus the length of its shadow at noon. While to Hanafi mathab Asr starts when the length of an object's shadow equals twice its length plus the length of its shadow at noon.
So ,

Asr = Z + offset
Where Mathab = 1 for Shafaii and 2 for Hanafi.

Summary:

To compute prayer times we need:

Know the location (latitude - longitude), time zone and date.
Compute Julian day, equation of time and declination angle.
Start by Douhr.
Then, compute Maghrib and sunrise.
After that, compute Fajr and Isha using appropriate convention.
Finally, compute Asr according to desired mathab.

Try to work out these calculations by hand.

References:

Some astronomical facts:
http://www.astronomicalfacts.com/article.html
The real helpful and correct source about prayer times.
http://www.ummah.net/astronomy/saltime/
Julian day and Equation of time calculator Javascript! Get its source to know method of calculation!
http://www.go.ednet.ns.ca/~larry/orbits/jsjdetst.html
Declination angle, sunrise, sunset PHP calculations step by step!
http://users.electromagnetic.net/bu/astro/iyf-calc.php

100 things we didn't know last year

2008-01-01T14:50:00.000+02:00

100 things we didn't know last year

The bbc has a weekly tradition called "10 things we didn't know last week" to highlight some interesting and unexpected news and posts every week. Also other annually "100 things we didn't know last year" to highlight 100 things from the weekly ones.

The weekly 10 things can be always viewed at:

http://www.bbc.co.uk/blogs/magazinemonitor/10_things/

The 100 things we didn't know last year 2007 at:

http://www.bbc.co.uk/blogs/magazinemonitor/2008/01/100_things_we_didnt_know_last_3.shtml

These are some highlights of the last year:

Saddam Hussein's codename while in US custody in 2004/5 was "Victor".
Only about half of China's population can speak the national language, Mandarin.
Serving anything more than tea and biscuits at a political meeting is an offence called "treating" and punishable by a year in prison or an unlimited fine, under the the Representation of the People Act 1893.
Denmark is the happiest country in Europe; Italy the unhappiest. (The UK was 9th out of 15.)
The secret to happiness is accepting misery.
Nearly seven out of 10 (69%) of adults are still in touch with at least one childhood friend.
CDs were nearly called mini-racks.
The brain can turn down its ability to see in order to listen to complex sounds like music.
Adults use maths skills 14 times daily on average and literacy skills 23 times a day.
In Ethiopia the start of the year 2000 was celebrated in September.

And these are some shots from last years:

The = sign was invented by 16th Century Welsh mathematician Robert Recorde, who was fed up with writing "is equal to" in his equations. He chose the two lines because "noe 2 thynges can be moare equalle".
"Restaurant" is the most mis-spelled word in search engines.
Cyclist Lance Armstrong's heart is almost a third larger than the average man's.
It takes 75kg of raw materials to make a mobile phone.
Bill Gates does not have an iPod.
It takes less energy to import a tomato from Spain than to grow them in this country because of the artificial heat needed, according to Defra.
The day when most suicides occurred in the UK between 1993 and 2002 was 1 January, 2000.
You are 176 times more likely to be murdered than to win the National Lottery.
Bill Clinton sent just two e-mails while he was president.
Bill Clinton revealed in his autobiography that he didn't learn to ride a bike properly until he was 22.
It's 30 years since the world's first barcode was used. It was on a 10-pack of Wrigley's Juicy Fruit at a supermarket in Ohio. The gum is now an exhibit in the Smithsonian Museum in Washington DC.
Hexakosioihexekontahexaphobiacs is the term for people who fear the number 666.
In America it's possible to subpoena a dog.
Poets die young... "On average, poets lived 62 years, playwrights 63 years, novelists 66 years and non-fiction writers lived 68 years," according to California State University's James Kaufman.
The Mona Lisa used to hang on the wall of Napoleon’s bedroom.
The word "time" is the most common noun in the English language, according to the latest Oxford dictionary.
In the 1960s, the CIA used to watch Mission Impossible to get ideas about spying.

And don't forget delay jitter is the variance of delay.

Last years 100 things:

http://www.bbc.co.uk/blogs/magazinemonitor/2006/12/100_things_we_didnt_know_last_2.shtml

http://news.bbc.co.uk/1/hi/magazine/4566526.stm

http://news.bbc.co.uk/1/hi/magazine/4134329.stm

Remember when.......

2007-12-18T16:30:00.000+02:00

كل سنه و إنتم طيبين

Do you remember nice days when there were no computers?

Remember when.......

A computer was something on TV
from a science fiction show of note
a window was something you hated to clean
And ram was the cousin of a goat

Meg was the name of a girl,
And gig was your middle finger upright.
Now they all mean different things,
And that really mega bytes!

An application was for employment
a program was a TV show
a cursor used profanity
a keyboard was a piano

Memory was something that you lost with age
a cd was a bank account
and if you had a 3.5" floppy
you hoped nobody found out

Log on was adding wood to the fire
hard drive was a long trip on the road
a mouse pad was where a mouse lived
and a backup happened to your commode

Cut you did with a pocket knife
paste you did with glue
a web was a spider's home
and a virus was the flu

I guess I'll stick to my pad and paper
and the memory in my head
I hear nobody's been killed in a computer crash
but when it happens, they will wish they were dead.

Reference and after computer invention:
http://hagar.up.ac.za/catts/abc/computersinschools/timeschange.htm

TV typewriter, A TV and a Typewriter

2007-10-12T09:21:00.000+02:00

TV typewriter, A TV and a Typewriter

From the historic stories which shows ingenuity and loyalty of a hacker is this one:

One poor MIT hacker had a motorbike accident and broke his leg. He stayed in hospital for a while. During this period two of his friends brought him a terminal and a modem to use his computer from the hospital.

When they went to the hospital they were stopped by the guard saying that it’s not permitted to bring terminals to the hospital, permitted things are: tape players, TVs, typewriters, radios … while computer terminals are not allowed.

They didn’t give up and came the next day and a guard stopped them again and asked them what are they carrying. They answered a TV typewriter. When the guard investigated the devices, they showed him that each character typed on the typewriter appears on the TV -terminal- instead of paper. Finally the guard said “A TV is all right, a typewriter is all right ... okay, take it on in!"

TV typewriters are real! But not that stated in the story. They are video terminals which display typed characters on a TV and they are connected to a keyboard. Low cost designs were available from 1973, invented by Don Lancaster and published in TV Typewriter Cookbook.

Cutting edge donkey© technology

2007-06-08T18:25:00.000+03:00

It was 04:00 am when IBM requested an application to show capabilities of PC-DOS and BASIC written by Bill Gates and Neil Thompson in 1981. Few hours later a fantastic game was written by these two guys in BASIC named DONKEY. This game was distributed with IBM PC packed with PC-DOC and BASIC.

At that time Microsoft was only six years old.

The success of this game leads to the development of DONKEY 1.10 which was released the next year in 1982.

This is a part of Bill Gates and Ari Bixhorn speech about DONKEY:

“Actually, it was myself and Neil Thompson at four in the morning with this prototype IBM PC sitting in this small room. IBM insisted that we had to have a lock on the door and we only had this closet that had a lock on it, so we had to do all our development in there and it was always over 100 degrees, but we wrote late at night a little application to show what the Basic built into the IBM PC could do. And so that was Donkey.bas. It was at the time very thrilling. So go ahead and show them what that looks like.”

The whole speech can be found at:

http://www.microsoft.com/presspass/exec/billg/speeches/2001/06-19teched.aspx

20 years later Microsoft remembered to support DONKEY development so it release the new version DONKEY.net which is a 3-dimensional game written in VisualBasic.net with the same aim of DONKEY 1.0 i.e. demonstrating the new capabilities of PC-DOS and BASIC sorry I mean Windows XP and VisualBasic.net.

Other part of the speech describing DONKEY.net

“And to help illustrate some of the great new capabilities that are available to VB developers in VisualBasic .NET, we've actually taken Bill's donkey game. We've scrubbed the code a little bit and we've updated it to run in VisualBasic .NET. That's what we see here.”

Donkey.NET game can be found at:

http://www.microsoft.com/downloads/details.aspx?FamilyID=990d0ec1-23ea-4408-898d-1fd5727a8890&displaylang=en

Conclusion:

Microsoft technology evolved during the last 26 years from 2D donkey.bas 132 lines of code to 3D donkey.net about 920 source lines -without generated code-.

As I remember from an article to Donald Knuth that he classified source code according to style to be elegant, sparkling, grand and noble. I couldn’t compare any of these styles on this code.

Neil Thompson:

Senior Regional Director, Northern Europe, Entertainment & Devices Division, Microsoft Corporation and was Microsoft's technical lead on the Mac project.

Ari Bixhorn:

Product manager for Visual Basic.NET.

Bill Gates:

Guess who!

Against DVD Piracy

2007-03-17T09:53:00.000+02:00

Against DVD Piracy

Statistics:

The total loss to the whole audio and visual industry through copyright theft, file sharing, and home burning is more than £818 million.
The criminal gain from DVD piracy is £278 million.

DVD piracy is making, copying, and burning even borrowing an unofficial copies of popular films being sold without the permission of film-makers and with no money going to the official rights owners. The most common way for DVD piracy is recording films with a camcorder from an audience during an early screening. Quality is weak in general. Piracy is an easy way for gangs to raise funds for their other criminal activities. Gangs can earn 10 euros (£6.65) for each euro invested in piracy thus 1000% profit.

Efforts devoted in fighting piracy:

The federation against copyright theft (FACT) an organization based in the United Kingdom that works closely with the UK police and plays a key role in creating awareness of the dangers associated with DVD piracy.

Motion Picture Association of America (MPAA) is a non-profit trade association. Its members are the "big six" major Hollywood studios: The Walt Disney Company, Sony Pictures, Paramount Pictures , 20th Century Fox , Universal Studios (NBC Universal), and Warner Bros. (Time Warner).
As results of MPAA activities in April and May 2005 the home pages of LokiTorrent and EliteTorrents (two large BitTorrent trackers) had been closed down because of encouraging the illegal distribution of copyrighted material defined as the distribution of copyrighted works without permission of the copyright holder.

Malaysia developed a strange scheme for fighting piracy. They trained sniffer dogs mining for illegal music and movies copies at airports or harbors.

The Domestic Trade Minister Shafie Apdal said "It's cost-effective, and in terms of time, it's very effective too, the dogs took only 10 minutes to check boxes that security officials would have needed a day to plow through". And added "The arrival and deployment of Lucky and Flo –the two dogs- will make Malaysia the first country in the world to test the capability of dogs in detecting optical disks in hidden compartments or shipments"

Malaysia was done in conjunction with the MPAA. Just imagine how dogs can be trained to mine for polycarbons.

Microsoft Shares Your Pain

2006-12-26T19:12:00.000+02:00

1% of bugs caused 50% of all incredible system errors.

Microsoft's error reporting system has reduced about 80% of system –as they say- errors which encouraged them to make a new way of error reporting.

Microsoft has evolved a new way of customer feedback system. The idea is that Microsoft knows how pain customers suffer when a failure happens in any of their systems. So, Microsoft's employees must share pain with customers.

Thus, WSYP project or We Share Your Pain. WSYP was developed by Microsoft team in United Kingdom. This project claims that Microsoft can discover which programmer who wrote the piece of code which is responsible for this failure. Then, cause him a physical pain. This is done by a special Aeron chair. So, instead of seeing a message of Send Error Report Don't Send the user will see a message of Share Pain Don't Share. Then the customer will happily choose one of the 3 options for punishing this programmer. And see a live video of the programmer sharing pain with him.

Option 1: Micro-Stun option

Electric shocks are generated through the chair arm sleeves.

Option 2: Micro-Impact option

The back of the chair releases back and thrusts forward into the person sitting, into the chair.

Option 3: Micro-Jab option

Watch it in the video.

There is also an ejection option to eject the programmers who have commutative serious bugs out of Microsoft.

Share and Don't Share message box.

Live video so that customers see the programmer cause their system to fail being punished with the selected option.

Micro stun in action

Ejection mechanism after serious errors

The video and the presentation can be found at:

http://www.microsoft.com/uk/technet/itsshowtime/sessionh.aspx?videoid=9999

A very interesting video

It's interesting to see how Microsoft feels customers' pains.
I have the video it's about 20MB

Microsoft believes that this system will reduce system errors massively.

And I think by know you don't care about being employed at Microsoft.

The first bug

2006-12-08T08:56:00.000+02:00

The first bug

Do you what's the first bug or where did the term "Bug" come from?

In 1945 and during the world war II Grace Murray Hopper and a team at the Harvard University were working on Mark II Aiken Relay Calculator.

This primitive computer was facing problems and matters were getting worth till they discovered the problem. It was a moth! A 2-inch moth was trapped at relay #70. The team used ordinary tweezers to remove that moth.

This photo is the log file left by the team.

Last line in this photo: First actual case of bug being found.

They said that they had “debugged” the machine. Thus they used “bug” to describe their problem.

Grace Murray Hopper (1906-1992) was an admiral at the American navy forces. The term “Bug” cannot be related to Grace Hopper because it was used before she used it. She made it popular. So this case didn’t introduce this term. “Bugs” was used during World War II to describe problems in radars. It was also during Thomas Edison's life to mean an industrial defect.

In days of telegraphy tapers need to send dots and dashes of Morse code. And there were the newer, semi-automatic keyers that would send a string of dots automatically. These semi-automatic keyers were called "bugs". These semi-automatic keyers require skilled operators. Or if you are not experienced you would send garbled Morse code.

Bugs and quotes:

Everyone knows that debugging is twice as hard as writing a program in the first place. So if you're as clever as you can be when you write it, how will you ever debug it? (Brian Kernighan)
When you say: "I wrote a program that crashed Windows", people just stare at you blankly and say: "Hey, I got those with the system -- for free." (Linus Torvalds)
Every program starts off with bugs. Many programs end up with bugs as well. There are two corollaries to this: first, you must test all your programs straight away. And second, there's no point in losing your temper every time they don't work.
There are no significant bugs in our released software that any significant number of users want fixed. (Bill Gates) have you any comment??
The only man who never makes mistakes is the man who never does anything. (Theodore Roosevelt)
Of all my programming bugs, 80% are syntax errors. Of the remaining 20%, 80% are trivial logical errors. Of the remaining 4%, 80% are pointer errors. And the remaining 0.8% are hard. (Marc Donner)
Sometimes it pays to stay in bed in Monday, rather than spending the rest of the week debugging Monday's code. (Dan Salomon)

So do you know where “Bugs” originated from?
I don’t know.

But it seems that Grace Murray Hopper case is the first actual bug found.

Esoteric programming languages

2006-10-23T15:47:00.000+02:00

Esoteric programming languages are not like ordinary languages used for real programming. Instead they have special purpose which can be testing boundaries of a computer or proving an algorithm or not more than a joke. These languages are understood by few people who are interested in them.

The first esoteric language is INTERCAL http://www.catb.org/~esr/intercal/ , was designed in 1972 by James Lyons and Don Woods.

INTERCAL is said by the original authors to stand for "Compiler Language With No Pronounceable Acronym"!!!??

Examples of some esoteric programming languages:

Sorted! Programming language:

Each Sorted! program contains exactly 14 statements, No more, no less.
Error checking in Sorted! is very simple: just verify the number of statements; if it has 14 statements, it will have a very high chance of working (compared to non-14-liners).
Sorted! is bilingual. It can understand both English and German code!
Each Sorted! program is, in fact, sorted, although randomly. Hence the name!
Sorted uses OPP for enhanced programming power.

See hello world example in Sorted! Which –as you know- contains 14 statement.

In English: http://p-nand-q.com/humor/programming_languages/sorted_/hello.txt

In German: http://p-nand-q.com/humor/programming_languages/sorted_/hallo.txt

Home page: http://p-nand-q.com/humor/programming_languages/sorted.html

Taxi Programming Language:

Philosophy of Taxi is that programmers move data from one memory location to anther thus like taxi driver moving people from one place to another. A Taxi needs fuel which is resources consumed by your program. And so on.

See hello world!

"Hello, World!" is waiting at the Writer's Depot.
Go to Writer's Depot: west 1^st left, 2^nd right, 1^st left, 2^nd left.
Pickup a passenger going to the Post Office.
Go to the Post Office: north 1^st right, 2^nd right, 1^st left.
Go to the Taxi Garage: north 1^st right, 1^st left, 1^st right.

Home page: http://www.bigzaphod.org/taxi/

Shakespeare Programming Language:

Shakespeare is designed by Jon Aslund and Karl Hasselstrom. As its name it tries to make programs look like plays wrote by Shakespeare. Code in Shakespeare is arranged as acts and scenes which reflects functions. Variables are characters in a play. To use a variable you must bring it to the stage.

Hello world in Shakespeare consists of 90 lines! And can be found at http://shakespearelang.sourceforge.net/report/shakespeare/#sec:hello

Home page: http://shakespearelang.sourceforge.net/

C-

Unlike well known C++ C- was created by John Unger Zussman, and It was described in the Info World article as follows:

This language was named for the grade received by its creator when he submitted it as a class project in a graduate programming class. C- is best described as a "Low-Level" programming language. In fact, the language generally requires more C- statements than machine-code statements to execute a given task. In this respect, it is very similar to COBOL.

Emoticon:

Emoticon is a programming language based on emoticons which we use in mails. These emoticons represents instructions while nay thing else is data.

hello world :-Q S:-P :-Q

hello	The data item 'hello' is placed on the right of the current list ':'
world	The data item 'world' is placed on the right of the current list ':'
:-Q	The left of the list ':' ('hello') is printed out and then removed
S:-P	The left of the list 'S:' (' ') is printed out
:-Q	The left of the list ':' ('world') is printed out and then removed

Home page: http://www.teuton.org/%7Estranger/code/emoticon/emoticon.html

J programming language:

The simplest language I have ever seen.

Hello world:

'Hello, world!'

Compute average:

avg =. +/ % #

avg 1 2 3 4

Generate random number between 20 and 100:

a =. ?20$100

Home page: http://www.jsoftware.com/

NULL programming language:

Every thing in NULL is numbers there is no characters

153609393637869503971282839335995386248921743204830348570033
550157913898858976126298703504031567456769368158187308369080
75646108694411913908753341542249057283074613678144889367

Find at home pace instruction set to program in NULL

Home page: http://xyzzy.bravehost.com/NULL.html

Now forget about Esoteric programming languages and continue using your native languages.

How to hunt an elephant ?

2006-10-02T22:33:00.000+02:00

I wasn't planning to make a series of how to do things but it was a nice coincidence to get this interesting article from Byte magazine.

How to place the right person in the right place?

This is done by:

Sending him to Africa hunting for an elephant and observing his behavior.

Computer scientists:

Use the following algorithm:

1. Go to Africa.

2. Start at the Cape of Good Hope.
/* A rocky headland on the Atlantic coast of South Africa */

3. Work northward in an orderly manner, traversing the continent alternately east and west until you get to Cairo,

4. During each traverse pass,

Catch each animal seen.
Compare each animal caught to a known elephant.
Stop when a match is detected.

This algorithm is used to describe a test data that is designed to ensure that an algorithm is working properly.

Now I will leave you with other various jobs.

"Taken from Byte magazine September 1989"

Professional programmers: Know that this algorithm may not terminate so; they place an elephant in Cairo first then apply this algorithm.

MS-DOS support people: will not bother to hunt elephants in the first place, because everyone knows that you can’t fit an elephant into 640K -memory barrier-.

Mainframe operating system designers: will all hunt the same elephant, and all claim credit for the kill on the grounds that each was working on a virtual elephant.

Software salespeople: ship the first thing they catch and write up an invoice for an elephant.

Hardware salespeople: catch rabbits, paint them grey, and sell them as desktop “elephants.”

Engineers: hunt elephants by catching grey animals at random and stopping when any one of them weighs within +/- 15 percent of any previously observed elephant.

Economists: don’t hunt elephants, but they believe that if elephants are paid enough then they will hunt themselves.

Statisticians: hunt the first animal they see N times and call it an elephant.

Politicians: don’t hunt elephants; they will share the elephants that you catch with the people who voted for them.

Database administrators do not need to go out and capture elephants when they can retrieve them simply with an ad hoc query: SELECT * FROM AFRICAN_CRITTERS 2 WHERE CRITTER_TYPE = 'TERRESTRIAL' 3 AND SIZE = 'LARGE' 4 AND COLOR = 'GRAY' 5 AND TRUNK = 'YES' 6 AND ODOR IS NOT NULL;

Systems integration engineers are not so concerned with hunting elephants as with creating a seamless interface between the elephants and their environment.

For other jobs:

http://homepage.eircom.net/~nobyrne/elephant.htm

How to ask a question?

2006-09-16T14:25:00.000+03:00

How to ask a question?

This article describes briefly the steps you must follow to ask a question to a mail group or forum. If you are sending a mail to our groups then we are simpler than these steps, you are using step #5 in before you send a question. Use these steps when you send a question to TAs and other mail groups or forums.

Before you send a question,

Do the following in the same order:

Search archives and FAQs
Use search engines.
Read a manual or book or help for your tool.
Find answer by try or experiment.
Ask a friend.

Prepare your question:

Show that you have done last steps and you failed, this proves that you are not lazy.
Show your steps in trying to solve the question.
Try to surround the problem, i.e. try to get the problem in the smallest block.
Describe your environment, e.g. operating system, compiler, others.
Identify yourself.
Compilers and other tools are trusted or to some extend so; don’t assume a bug in them.

When you ask:

Choose the most relevant community to ask.
Use a meaningful, exciting subject that attracts people to read. Don’t simply use “I need help”, “I got error” as subject.
Try to be clear, write a question in a careful way, free of spelling and grammatical mistakes.
Give all information and only information needed. Don’t waste time by describing your design which will not affect the problem.
Don’t let people ask you again about details.
Don’t send you guess instead try your guess yourself if it doesn’t work wait for a reply and send then your guess.
Send questions in easily accessible format. Use standard fonts. You know problems of character encoding.

After getting an answer:

Tell the replier if his answer fixed your problem or not.
Send a small delicate thanks reply for the person wasted his time for you.
You may send a report of the problem and steps in solving it.
Prevent others from following the same steps in solving that problem, I mean reduce their efforts.

Finally smart question attract repliers to answer. Also, new idea sounds well. If you got no reply then, don’t panic may be repliers have no answer. And remember Ask the right question to get the right answer.

Links:

http://support.microsoft.com/kb/q555375

http://www.catb.org/~esr/faqs/smart-questions.html

Common programmers' personality

2006-08-17T10:28:00.000+03:00

Before;

A computer programmer may have a character different from a normal person. Oh! I am sorry, he is a normal person but, I mean a person at other work.
Note: This article doesn't reflect my personal opinion but some statistics collected on software programmers especially engineers.

Common programmers’ character:

The following personality is common among programmers:

Can concentrate 12-16 hours at a time.
When interrupted responds violently.
Use only his head and hands.
Less adaptive and have small social activities. Even concerned with computer. e.g.: chat, mail groups, forums, etc.
Quiet serious and shy.
Practical and logical.
Low motivation towards management responsibilities.
Loyalty to the profession rather than the employer.
Optimism regarding time estimates.

This personality traits was applied to programmers despite their particular work(system analysis, design testers ,etc..).

MBTI Results for Software Developers

A common mean of categorizing personality was developed by Katherine Briggs and Isabel Briggs Meyers and is called the Meyers-Briggs.

Table -1- Personality Type of MBTI test

Extraversion Expressive, Process by talking Speak before they think Need contact	Introversion Can’t process while anyone is talking Think before they speak Need time alone
Sensing Observant Experiment Attention to detail	Intuition Imaginative Theory Bored by detail
Thinking Practical Objective Being right	Feeling Personal Sympathetic Values and feelings
Judging Scheduling Love to make plans and stick to them Hate to change them	Preceving Probing Can’t stand plans More flexible

Two large studies have found that the most common personality type for software developers is ISTJ (introversion, sensing, thinking, and judging)

Introverts are more interested in the inner world of ideas. Not oriented towards people.(54%)
The sensing person focuses on known facts, concrete data, and experience. Not concepts and theories.(57%)
The thinker makes decisions based on objective analysis and logic and never relies on his emotions.(81%)
The judging person prefers order and control, not possibilities and flexibility.(54%)

A try to analyze these results

May be reasons to this character is education. Programmers are highly educated and almost got pressured.

Software programming career

About 60% of software developers have a Bachelor's degree or more.

Programming job is highly rated in terms of salary, working conditions (air conditioned well lighted offices) job security (almost no risk).

A study at IBM found that the average programmer spends only about 30 percent of the time working alone. The rest is spent working with teammates, with customers, and on interactive activities.

Challenging projects extend programmer’s capabilities, test his limits and apply practices. A challenging project may take from 2 weeks to years. Challenging projects generally done lonely.

A programmer can sacrifice his life to programming challenge especially during 20s. This fact bec0mes harder to justify when he marries and gets children move into their 30s, 40s, and 50s.
As he grows older. He relies more on working smart than on working hard. Software developers will become increasingly interested in the practices that allow them to complete their projects as promised and still be home in time for dinner(only dinner). They become interested more in software engineering professionalism.

Table -2- Percent of Software Developers Education in U.S

High school graduate or equivalent or less	10
Some college, no degree	21
Associate's degree	10
Bachelor's degree	45
Graduate degree	14

*Table -3- Worldwide Software developers grow*
1950	100
1960	10,000
1970	100,000
1980	2,000,000
1990	7,000,000
2000	10,000,000
2010	14,000,000
2020	21,000,000

Table -2- shows education of software developers’ ratios in U.S.
While Table -3- shows population of software developers from 1960 to 2020

After;

Do you think this article applies to you??

Links:

http://cs.anu.edu.au/~Ian.Barnes/research/slides.html

A research done by Ian Barnes from The Australian National University on personality type and software development

http://www.eng.monash.edu.au/uicee/worldtransactions/WorldTransAbstractsVo1No2/17_Capretz14.pdf

A comparison between the personalities of software engineers students and engineers in general. Above statistics were done on software engineers not students.

A computer scientist

2006-07-17T09:08:00.000+03:00

An English mathematician ,mechanical engineer and computer scientist who designed the first true digital computer. He spent most of his life building his mechanical computer. He built his computer to overcome the problems of high human calculations and slow rate.

How can a mechanical computer be a digital one? You may think that wheels and gears can represent and manage digits.

This machine -Difference engine- has a fantastic architecture that is similar to modern computers. Data and program memories were separated. And operations were instruction based. It had a control unit and can make conditional jumps. It has time signals and separate I/O unit.

He also designed a printer with variable column and row length and programmable output formatting.

After that he designed a more complex machine -Analytical engine- that can be programed by punched cards. This machine was also intended to have several operations such as branching, and looping.

A young lady Ada Lovelance the daughter of the famed British poet Lord Byron was hired to write software for this computer. She was of few people who knew lot about the Analytical engine. Ada is regarded as the world's first programmer. The programming language Ada® in 1979 is named after her.

This scientist is Charles Babbage 1791 - 1871 who a crater on moon -Babbage crater- and Charles Babbage Institute in United State were named after him. The science fiction novel The Difference Engine refers to him. He was elected as the fellow of royal society at 1816.

References and farther reading:

http://en.wikipedia.org/wiki/Charles_Babbage
http://www-history.mcs.st-andrews.ac.uk/~history/Mathematicians/Babbage.html
http://ei.cs.vt.edu/~history/Babbage.html

Case study 2 : Goodrich case

2006-06-24T15:37:00.000+03:00

Goodrich case

On June 1967, the B.F. Goodrich Wheel and Brake Plant in Troy, Ohio, received a contract to supply wheels and brakes for the new Air Force light attack aircraft. Before Air Force could accept the brake, B.F. Goodrich had to present a report showing that the brake passed specified qualifying tests.

On April 1968, Kermit Vandivier-Goodrich employee- got involved in looking over raw data from the brake tests. He observes that many irregularities in testing methods were noted in the test logs. Thus the tests missed the government specifications.

On may 1698, Vandivier refused to write a falsified qualification report, and is backed up by his immediate supervisor, Ralph Gretzinger.

Following brake failure flight tests at the June, 1968, Vandivier, accused Goodrich of false test qualification report.

On October 1968, Chief Engineer Sunderman calls Vandivier in and dismisses him immediately for disloyalty to Goodrich. Sunderman asks Vandivier if he will take further action. Vandivier says, "Yes." Sunderman responds, "Suit yourself."

In 1972, Vandivier wrote an article entitled "Why Should My Conscience Bother Me,”. His article formed the basis of what is now known in professional business and engineering ethics circles and the literature of whistle blowing as "The Aircraft Brake Scandal."

Vandivier lost his job for doing things right.

Case study 1: Gifts accepting

2006-06-12T17:29:00.000+03:00

Case study 1: Gifts accepting

Imagine you are working at a company and you are given a gift. Now you are to decide whether you accept it or not.

You are given a small gift e.g. a nice pen.
You are given some thing valuable.

Concept of bribery:

Bribe: is the money or any thing else given to somebody such as an officer to encourage him to do something dishonestly.

Bribery: is the action of doing this.

Examples:

A motorist may bribe a police officer not to record a ticket for speeding.
A citizen seeking paperwork may bribe an official for faster service.
A construction company may bribe a civil servant to award a contract.

How to determine bribery:

Method of casuistry:

A judge decides a case by comparing it with previous cases.

Here is an example of this method.

Moral rule: "People should not steal (or commit theft).

Breaking into a store and taking $3000 in merchandise.
"Borrowing" a friend's car and failing to return it.
Developing a computer program on company time for your company, and then patenting a considerably improved version of the program under your own name.
Using some ideas you developed at Company A for a very different chemical process at Company B.
Picking up a quarter that you saw someone drop on the street.
Picking up a quarter that someone (you don't know who) has dropped on the street.

Can you decide whether of the last actions broke the moral rule?

Is not easy to determine which gift is a bribe. Drawing an exact line separates bribe from normal gift is hard. Other idea is why is a customer gives a gift? Will he gain any thing from this?

An electronic company considered the following gifts as bribe:

door prizes at a conference;
raffle prize by a supplier or distributor;
any gift of excessive value (supervisor must be notified);
fare lower than commercially available;
cash rebates;
tickets to sporting events or other entertainment given as an outright gift where the supplier does not intend to accompany the employee;
sports team sponsorship by supplier;
extravagant dinner or entertainment; and
Any gift, favor, hospitality or entertainment that could in any way create a feeling of obligation or could compromise professional judgment.

Engineering ethics

2006-06-09T09:10:00.000+03:00

Engineering ethics

Are we engineers or computer engineers? We are engineers before being computer engineers.

Engineering ethics have taken recently great care in engineering faculties. This was reflected in development of courses to under graduate students. Number of students who wish to study this course is increasing.

Engineering has no definite or known ethics such as medicine judgment law and military. Yet still this ethics must be defined. What moral issues should an engineer acquire?

The National Science Foundation NSF-funded a research project, "Introducing Ethics Case Studies into Required Engineering Undergraduate Courses," completed in August 1992. Professor Michael J. Rabins in the Department of Mechanical Engineering and Professor Ed Harris in the Department of Philosophy at Texas University developed this course and tested it on 11 students and instructors.

The most important result of this work was case studies.

So, we will take a survey of case studies.

http://ethics.tamu.edu/

Making of BMW e46 3 Series

2006-06-03T18:01:00.000+03:00

This video is of my favorite car.

It isn't about exciting features of this car nor racing or driving comfort ability.

It's about manufacturing of this car or simply making of BMW.

So, you can take a tour inside BMW factories starting with metal-sheets cutting and shaping till last performance testing.

My notice is how workers are cheerful doing their work. Will we enjoy our work?

Now I will leave you with the video. Hope you enjoy it.

If you have any difficulties in buffering this video just wait for few minutes.

I may send it to you. It’s about 22 minutes. Or you can have instructions on how to download it.

The Third Culture

2006-05-19T16:06:00.000+03:00

Science and Art and "The Third Culture"

Computers -since invented- have been an interesting tool for all. We mean now artists and scientists. This gave great opportunity for both to interact with each other. Artists are interested in great technologies and discoveries made by their mates (scientists). While Scientists are inspires by humanities and great meaning given by artists. So we have two cultures Science and Art. This will evolve the third culture.

We now will define the word science as the study of physical and experimental issues. So a scientist is a person who studies or teaches science.

While art is defined as beautiful things or a skill acquired to a person. It may also be the meanings of words, colors, pictures, nature, many things.

So the third culture tries to tie both Art and science.

Science fiction is an example of this third culture. Here the writer or the poet knows much abut science and art. But, he can use some words outside their context such as "black hole". This is never wrong. It never bothers scientists.

If Science and Art share the same problem, the main difference between them will disappear and will be only the style or the way of solving the problem.

Links:

http://www.edge.org/3rd_culture/
http://vv.arts.ucla.edu/publications/publications/00-01/ThirdCulture/ThirdCulture.htm

Hackers' folklore ”Story of Mel”

2006-05-10T00:25:00.000+03:00

Hackers' folklore

This piece of folklore ”Story of Mel” was written by Ed Nather in 1980 for his friend Mel Kaye a true programmer credited with doing "the bulk of the programming" for the Royal McBee LGP-30 drum-memory computer in the 1950s.

Real Programmers write in FORTRAN

Maybe they do now,
in this decadent era of
Lite beer, hand calculators, and "user-friendly" software
but back in the Good Old Days,
when the term "software" sounded funny
and Real Computers were made out of drums and vacuum tubes,
Real Programmers wrote in machine code.
Not FORTRAN. Not RATFOR. Not, even, assembly language.
Machine Code.
Raw, unadorned, inscrutable hexadecimal numbers.
Directly.

Lest a whole new generation of programmers
grow up in ignorance of this glorious past,
I feel duty-bound to describe,
as best I can through the generation gap,
how a Real Programmer wrote code.
I'll call him Mel,
because that was his name.

As you see the author was fascinated by the old beautiful difficult days of programming where no compilers even assemblers. All programmers had to write their programs in machine language doing computations manually.

Then he starts to introduce his friend Mel a real programmer who he met in Royal McBee Computer Corp. Well the author Ed Nather was hired to write a FORTRAN compiler and Mel didn’t approve this as he said: "If a program can't rewrite its own code", he asked, "what good is it?"

This story is now regarded as one of the most famous pieces of hacker folklore.

Read the complete story:

http://www.cs.utah.edu/~elb/folklore/mel.html

Find out the Blind Spot

2006-05-01T16:51:00.000+03:00

Find out the Blind Spot

Each of your eyes receives a different picture from the other. And the brain collects each of the pictures received by the 2 eyes and merges them into single 3 dimension picture which you see.

What happens if you receive only one picture?

Try this: I think you are in front of the computer about 50 cm. Close your right eye and concentrate on the cross mark in the picture below you see it and the black ball.
Now move slowly towards the screen and observe.

You will notice that at about 30 cm the black ball disappears.

Now what happens?

Each eye has a blind spot in the retina (The retina is a thin layer of cells at the back of the eyeball). This blind spot contains no photoreceptors (cells which receive the light).Thus, preventing the complete picture from getting to the brain.

So, Why is the Blind spot ?

This design allows a good blood supply close to the retina to both nourish the photoreceptors and help metabolize debris that accumulates there.

The other eye fill this black spot in most cases and even if the other eye doesn’t provide useful information the brain has mechanisms to fill in the hole. This filling in is why you see the white background.

Thanks god for great creation.

Read more:

http://serendip.brynmawr.edu/bb/blindspot1.html

http://serendip.brynmawr.edu/bb/blindspot2.html

http://www.exploratorium.edu/snacks/cheshire_cat.html

http://en.wikipedia.org/wiki/Blind_spot_(vision)

Errors & Bugs

2006-04-24T12:02:00.001+02:00

Errors & Bugs

Absolutely all of us face errors in writing programs (Compilation and runtime and others). Some give up some make massive changes while others try to follow errors and never change code or idea.really I don't know what is the best choice but I think it depends on the project itself and on the programmer.

Well I will tell you about some errors I faced.

First error: When I compiled a project (signal flow graph) a nice error appeared.The error was multiple declaration for class List see earlier declaration actually they were more than one error. I compiled the program more than once but the same error List was a template class so I thought that was because of template errors or due to multiple inclusions from several files. All didn’t work. Finally I decided to trace the earlier declarations. I found that the earlier declaration was in other project (Sorting techniques) although the project file was not included. WOW! Yet I was very pleased that I closed the computer. Never work in 2 projects in the same time simply, delete one of them to be far from errors.
No comment.

Other error was in sorting techniques project the project compiled normally with 0 errors and some warnings but when I removed the checkbox of Build with runtime packages the following error appeared fatal linker error cannot find the file “perfgrap.obj”!! What is that file and who included it I don’t know? When I removed the checkbook the project compiled normally I made a new project added all files to that and compiled it with the same error so, what to do now?? I had a small idea I brought any object file from any project and copied it to the project directory then renamed it to “perfgrap.obj” then compiled the project. It compiled successfully and ran normally!

Past errors were all compilation errors what about run time errors?
One of the strangest errors I saw was privileged instruction error! I think it was the responsibility of the compiler to fix that error. other was Paging file error when I see this types of errors I do nothing more than compiling the project more than once.

What’s an error?

(Compilation) Not following the language rules.
(Runtime) The condition of preventing the program from continuing running normally.

What’s a bug?

A bug is a mistake or failure that prevents it from working normally or produces incorrect or false result.

Linus Travold "Given enough eyeballs, all bugs are shallow".

Advices for programmers:

1-Write smart compressed small code : e.g. to copy a string: while (*s++ = *t++) ;
2-Go back and enhance your old code.
3-Learn from your IDE.( Language features IDE features help…)
4-Development on a fast-super computer.
5-Write lots of comments.
6-Use accessors or properties rather than public data.
7-Be aware with input and organized with output.
8-All special cases must be handled immediately; you'll never go back and fix them.
9-Design first (on paper in mind) then code.

China president at Gates house, not White House

2006-04-17T18:51:00.001+02:00

China president at Gates house, not White House

SEATTLE

Where do you think the first dinner of the historic visit of China’s president Hu Jintao to United States?

The White House? No.

It won't be in Washington D.C., but Seattle,The capital of Microsoft, and the Tuesday dinner will be held at the $100 million lakeside mansion of Microsoft founder and the world's richest man, Bill Gates.

The approximately 100-person guest list is a who's who of the U.S. Pacific Northwest power elite, including Starbucks Chairman Howard Schultz and Washington State Gov. Christine Gregoire.

Gates and Gregoire are expected to introduce and welcome Hu, who will then offer a toast in front of the gathering.

Like any good dinner guest, President Hu will not come empty handed. The Chinese government issued a decree two weeks ago that all PCs will need to have licensed operating system software installed before leaving the factory gates in an effort to crack down on piracy.
As a result, three Chinese PC manufacturers announced plans to buy a total of over $400 million worth of Microsoft Windows operating system software over the next three years and Lenovo Group, China's largest PC maker, is expected to announce a similar deal on Monday, organizers said.

This event is not so good for Linux lovers as it closes the door for Linux poularity in China(one of the greatest hosts for Linux).

Gates' lodge-style, 66,000-square-foot home overlooking Lake Washington with a reported seven bedrooms, six kitchens, 24 bathrooms, a domed library, a reception hall and an artificial estuary stocked with salmon and trout.

Gates lodge

The dining room overlooks the river!

http://www.gateslodge.com

Why People Don’t Work Like Elevators?

2006-04-07T13:31:00.000+02:00

Why People Don’t Work Like Elevators?

Your reaction to intensive signals is faster than less intensive ones.

Do you know why?
Do you understand?

Consider the following 2 examples:

You are in a hurry and waiting for the elevator what will you do?
You will push the elevator button strongly and repeatedly, but do you think that this will bring the elevator faster? In other words do you think that the elevator will respond to you faster in that way?
You may imagine that but absolutely that is never true.

Now if you shout at your friend then (s)he will respond to you faster than simply calling him so, why people don't work like elevators?

People respond to brighter light, louder sound faster than other this known as Pieron’s Law

Reaction Time is the time between the action and your response.

I is the physical intensity of the signal.
R0 is the minimum time for any response
K and b are constants that vary depending on the exact setup and the particular person involved.

A graphical representation showing last relation can be shown:

In fact, Pieron’s Law holds for the brightness of light, the loudness of sound, and even the strength of taste.

To see why, think of it like this: Pieron’s Law is a way of saying that the response time increases but at a decreasing rate, as the intensity.

Tom Stafford &
Matt Webb