Nov 25, 2009

Squirrel emergency solved

It was scary...I was hearing sounds, felt like someone was sneaking around, but every time I went downstairs I could not find anyone or anything and guessed that may be my roommate's cats were playing around. But this morning I found the cats were also getting crazy and they were scratching the fireplace window, crying for help. At first I thought some birds or rat got stuck into our fireplace , first I saw its eyes, is it a bird ! now I could see it, a big rat..with a big tail..oh my GOD, now I have to deal with rats :(( when I went closer, I figured out it was actually a squirrel, jumped down into the chimney and then imprisoned itself inside our fireplace.
We never lite fire , so the fireplace is always closed. My job was easy- open the window and let it out. But I was not sure how to deal with the cat situation, the squirrel already wounded himself struggling its way out and the cats were mad because they were not sure what the hell was making the wired noise for hours. I was relieved that at least it was no thief or rat or bird. It would be harder to handle those creatures. What if I cannot let it out ? Will it drop dead inside the fireplace ? I never opened the fireplace and was not even sure if my landlady would be ok with that. Finally we managed to take the cats away, open the fireplace and now it's time to get the squirrel out, but after seeing us, humans, it got scared and then we tried to lure it out with foods, kept the door opened and hid behind the stairs, after a while it realized that no human is going to attack and went outside , I was also relieved that no living creature is going to die inside my chimney , at least for the time being.

Oct 22, 2009

my Twitter network

click to see the larger image of my twitter network
It seems that among all the people I follow on Twitter, Shafi( rajputro) spends most time on twitter and Ragib vai has the most followers.The bigger the circle is, the more is the number of tweets of that person, and deeper shade of color indicates they have more followers. In both cases, Rajputro seems a winner with the largest circle with moderate blue color :) I created this visualization using NodeXL.

Sep 17, 2009

Git Tutorials for Begginers

Obama speaks at College Park, about the health care reform plan

Barack Obama just finished his speech 30 minutes ago, his words were vigorous as always , and though I am not an American citizen, it was inspiring for me too, it is always great to see a nation walking forward for change ! I went to the University of Maryland Comcast center at 10:30 am, September 17th,2009 and it is so huge that even I reached late there were plenty of available seats. People came with their children and parents, so it became more of a peublic event rather than campus campaign. A number of medical professionals, army people and congressmen were there.You can read more about it here.

As a student of UMD, I did not have to make much plan for it, just came to the campus at usual time and followed the crowd. I thought there would be a scene with security check at entrance, but the security people were quite easy going. I remember I could not enter the American Embassy in Bangladesh with my pendrive, but here they did not mind at all.Obama enteried at 11:48am , and finished his speech before 12:30, and the crowd really enjoyed because he gave much emphasis towards the young audience. One guy among the audience started booing him but could not make much of it, because another supporter lady was just about to punch that guy :) Then the security people came and take him outside, otherwise I think it would not be safe for him to stay among a hall full of supporters and shout against health care reform plan.

I still do not understand much about USA health care system, but it makes me really surprised that how can people go against this kind of initiative. Right now I am signed up for a class project that analyse US Health insurance situation, for this project I still need to gather more domain knowledge in this field, but what I understand is that if government wants to provide something more, there should not be any voice against it at all . And it is always great to have a leader who can cheer you up with his words of hope ( no matter whether they come true or not ) , 'cause hope and confidence can indeed make the difference.

Obama finished his speech heating up the atmosphere and instilling energy among the students, as a mere observer I can just hope that he succeeds with his mission for change.

Sep 7, 2009

Microsoft Research's MySong: play your songs with MySong

you sing your song, software plays the instruments for you :)

MySong is a system that automatically chooses chords to accompany a vocal melody. A user with no musical experience can create a song with instrumental accompaniment just by singing into a microphone, and can experiment with different styles and chord patterns using interactions designed to be intuitive to non-musicians *.


Floating point processors to simulate artificial neural activity

"We want to create an artificial brain that can communicate with a real brain,” says José Nuñez-Yañez, from Bristol’s Centre for Communications Research, as they’ve come up with a method to model neural activity with enough detail and speed for living cells to talk to synthetic neurons. Previous efforts to model neural activity have relied on supercomputers and generalized processors that are not good enough for parallel processing and again, these machine models are so complex that it can take 30 days to process one second of activity . But field-programmable gate arrays (FPGAs) rely on floating-point processors, with perhaps 1000 processors running in parallel. So this kind of processors can be an answer to the problem. Floating-point representation results in smaller rounding errors and therefore can be more precise. That precision is important for modeling neurons.

We know that Neurons communicate by exchanging spikes of voltage, which last a few milliseconds and may peak at about 70 millivolts. The timing of the spikes is important. In a fixed-point model, rounding errors accumulate, leading to a significant shift in the timing of the spikes. Therefore, floating point model can improve the simulation . The researcher at Bristol are so optimistic about this new idea is that their next step is to have a biological neuron talking to an artificial one. The idea is to take slices of mouse brain and incubate them on top of a sensor. After about two weeks of growth, the neurons will begin communicating as they would in the brain ! An analog to digital converter will measure the voltage produced by these neurons, send it to FPGAs, and different part of neural activity will be analyzed by the computers. I am here just rephrasing the idea that I read from this article published on Spectrum and I am really looking forward to the result of the next step.

visit ot Luray Caverns, Virginia

after arriving at the USA my first few days were really exhausting, and I was tensed as I could not find any suitable place to live yet, at that time I was not that excited about visiting any place, but still made the trip to visit the legendary caverns in Virginia.

We started from Washington, DC and the journey took at least two hours. As we went closer to the caverns, the nature around us became more and more beautiful.But the real beauty was yet to discover inside the caverns. It is amazing how nature has created this marvel that resides underground, the walk was long but worth it.

Jul 22, 2009

Preparation - 1

now I have got my visa and bought the ticket, so starts the final preparation; My friends know how clumsy I am , and thanks to all of them, they remind me the 'todo's time to time, the list of works I should finish before leaving home. the most important thing in my todo list is to sleep and I am happy that after a long time I am enjoying my time lying in bed all day long :)
We also prepared a list, the items one should bring with to USA from Bangladesh, I will be missing a lot of things, but there will be little room for all these things, so I am filtering out the less important ones .
My sisters bought presents for me with the money they saved , and I also got nice presents from my colleagues. I was surprisingly nervous on the last day at office. Still wondering how will it feel at the airport !

Jun 8, 2009

The Twilight Saga-Stephenie Meyer- download pdf and read

All the 4 'Twilight' novels of the series by Stephenie Meyer are here :

The books in the series in chronological order:

Finish reading before you see the movies :)
The download link is this.

May 15, 2009

Bangladesh Liberation War : A History in Short

We have read books about the Liberation war of Bangladesh, we watched films that depicted the sacrifices of our freedom fighters, yet politicians have tried to use this glorious history for their own interest. Muhammad Zafar Iqbal, a renowned and popular author of modern Bangla literature has tried to give a short narrative of this history from a neutral point of view on his book "Muktijuddher Itihash ( History of Liberation War)" . The great thing is we can download this book for free and read the whole book in just one sitting. This book is available both in Bangla and English in pdf format.

Some more web sites for dependable information about Bangladesh liberation war :


Genocide Bangladesh

All Quiet in the Western Front by Erich Maria Remarque

It's one of my most favorite books [pdf] .
I have shared a copy so that anyone can download this classic .

Apr 16, 2009

Mount using NFS in Ubuntu

We can use NETWORK FILE SYSTEM protocol , NFS , to share file in linux distributions.
we just have to follow some easy steps and then we are done, the nfs client machine is the one that can use a shared mount point of another machine. The machine that shares or exports its one or more directory to the client machine is called the nfs server. So if directory 'shared' is in the nfs server and some directory 'abc' in the client machine is mounted to access it using nfs, we can access the contents of the directory 'shared' from the client machine as all content of that directory will be available on directory 'abc'.

There I found very useful and easy steps:

So, /etc/exports file is to be modified in the server machine to define which directory is to be shared, who can access it, to what extent and with what type of permission ( add entry for directory 'shared').

/etc/fstab file is to be edited for new entry in the client one to define which directory is to be considered as a mount point ( add entry for directory 'abc' ).

Mar 15, 2009

Higher Studies-1

yes, the breathtaking, suffocating wait is over now, I have at last got my admission offer.. and not from only one university, what a relief.. after all the sleepless nights, efforts and praying, Allah bestowed His blessings upon me, and it was more than I deserved !
It was hard to make the decision, which university should I select to apply to, and what was my chances ? Am I really capable of ? Am I being too optimistic ? Am I being too negative about myself by not applying to the big names ? I still cannot figure out what was the algorithm to choose those 10 among the list of 00 universities of USA and Canada..
And now I have to choose which university's offer to accept ! Ya, it feels good to have options though there's always the risk of making the wrong decision, but that's life, and we always need to choose.
I finally decided to go for University of Maryland , college park, one of the big names that come when we talk about higher studies in Computer Science, so I was more than happy to get their acceptance.
Then comes the time for preparation !

Feb 14, 2009

some poems by Jibonanada Das

Bonolota Sen

For thousands of years I roamed the paths of this earth,
From waters round Ceylon in dead of night
to Malayan seas.
Much have I wandered. I was there
in the gray world of Asoka
And Bimbisara, pressed on through darkness
to the city of Vidarbha.
I am a weary heart surrounded by life's frothy ocean.
To me she gave a moment's peace -
Banalata Sen from Natore.

Aabar Bochhor kuri pore

Amidst a vast meadow the last time when I met her
I said: 'Come again a time like this
if one day you so wish
twenty five years later.'
This been said, I came back home.
After that, many a time, the moon and the stars,
from field to field have died, the owls and the rats
searching grains in paddy fields on a moonlit night
fluttered and crept! - shut eyed
many times left and right have slept
several souls! - awake kept I
all alone - the stars on the sky travel fast
faster still, time speeds by.
Yet it seems Twenty-five years will forever last.
(After Twenty-five Years translated by Luna Rushdi)

Aat bochhor ager ek din

Nevertheless, the owl stays wide awake ;
The rotten still frog begs two more moments
in the hope of another dawn in conceivable warmth.
We feel in the deep tracelessness of flocking darkness
the unforgiving enmity of the mosquito-net all around ;
The mosquito loves the stream of life
awake in its monastery of darkness.

-One day eight years ago, translated by Faizul Latif Chowdhury]

Jan 26, 2009

Reverse Proxy and Forward Proxy Server

When I was in high school it was very common to bunk the class and request one of my classmates to give proxy for me when the teacher makes the roll-call. In the university this proxy thing was more popular, so when it came to learn about proxy server, it was not much hard to understand that one server( the proxy one) is doing some stuffs on behalf of another and the world does not know that it is the intermediate proxy one. But there are two types of proxy servers, reverse proxy and forward proxy. As the idea of reverse proxy came later, so it's way of work is called 'reverse' and what we used to call proxy servers, are now commonly called 'forward' proxy to avoid confusion.

Proxy se

A proxy server is a machine which acts as an intermediary between the computers of a local area network (sometimes using protocols other than TCP/IP) and the Internet.
Most of the time the proxy server is used for the web, and when it is, it's an HTTP proxy. However, there can be proxy servers for every application protocol (FTP, etc.).

The operating principle of a proxy server:

The basic operating principle of a proxy server is quite simple: It is server which acts as a "proxy" for an application by making a request on the Internet in its stead. This way, whenever a user connects to the Internet using a client application configured to use a proxy server, the application will first connect to the proxy server and give it its request. The proxy server then connects to the server which the client application wants to connect to and sends that server the request. Next, the server gives its reply to the proxy, which then finally sends it to the application client.

Reverse Proxy:

A proxy server that resides at the Web site and all incoming requests to the Web server are routed to the reverse proxy. A reverse proxy adds a layer of security by hiding the details of the Web servers from the clients. The reverse proxy can be located in a comparatively less secure area and the Web servers can reside behind a secure firewall. It can also serve some other utilities, like encryption, compression and image caching on behalf of the actual web server. It can store dynamic pages generated by the web server and forward these to slower clients time to time. If any change is made to the web server like the URLs are modified, the port numbers are changed or new firewalls are deployed, then we don’t need to publish the new urls, only reconfiguring the reverse proxy will do, the clients can access the same urls without getting any 404 message. Those requests for the old urls will be translated to newer ones by the proxy and forwarded to the web servers hiding the changes to the clients.
We can consider this general scenario: suppose our application runs on port 8080 on tomcat, now-

* External requests are initiated on port 80.
* Firewall/Nat forwards the request to proxy server.
* Proxy server examines the requested URL and redirects it to web server.
* The server gives reply to the proxy which sends it back to the client.

And then we change the tomcat port to 8081 , but we do not need to publish the modified new urls, we just reconfigure our proxy server to forward those requests to 8081 and we are done!

A reverse proxy is sometimes called SERVER ACCELERATOR because its caching function can improve the performance overall.
It also makes the internal network more secure as it hides the details to external clients.
It can also perform load-balancing by distributing requests to several similar servers.

Forward Proxy :

When we talk about proxy servers we generally mean the forward proxy, that's why the other one is called reverse proxy :),the proxy servers are used to hide the details of the clients from the servers and are thus known as "forward proxies." Several client machines are connected to a proxy and they send their requests to the proxy.

If we configure our network’s DNS for internal use only, then a user inside the private network can access the network properly, but external users won’t. So proxy forwarding is needed to access resource inside the network.

The proxy server has two network interfaces and two IP addresses. The IP address on the outgoing side of the proxy is the one the Internet sees, and all the IP addresses of the client machines are hidden from the outside network.