Dr. Volkan Tunalı's Personal Blog

Computer, Technology, Science, Art

Why I Like Twitter

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twitterWhen everybody around started to use and talk about twitter, I preferred to stay away for a while in order to get the idea why so many people became twitter user and what I could make use of twitter. However, best way to learn about something is to get involved and explore, so eventually I’ve become a twitterer.

Before twitter, the best way for me to follow some person or news source was to use RSS feeds provided by the blog of that person or the web site of the news source. Today, I still effectively use RSS feeds for the same reason (mostly to read daily news). However, people usually have many more things to say but not to prefer to type into their blogs as posts. For example, I find a very good article about data mining, I want to share it to my followers, but it may not be feasable to write about that article in my blog. I don’t like to put a single-sentence blog post that only gives a link to the article. Then, twitter is very handy in such situations. I follow some important Computer Science researchers, and they usually give very useful links in their tweets besides links to their own new blog posts. I understand why use of tools like twitter and FriendFeed is called micro-blogging.

This basic usage style is more than enough for me to stay informed about people I follow. I have not got into deeper features of twitter like trending topics, lists, etc.

As long as used wisely, twitter is a simple, useful, and effective tool for information flow among people. I like it, I use it. You can follow me via @vtunali.

Written by Volkan TUNALI

August 13th, 2010 at 2:58 am

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Proof that P is not Equal to NP?

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Complexity ClassesFor a few days, everyone in the field of computer science has been talking about the manuscript P ≠ NP published by Vinay Deolalikar from HP Research Labs on August 6, 2010. The 102-page manuscript on the P versus NP problem has taken so much attention from computer science researchers like Scott Aaronson, Greg Baker, and Dick Lipton.

Let’s see what Wikipedia says about P ≠ NP as a refreshment for the subject:

The relationship between the complexity classes P (Polynomial time) and NP (Nondeterministic Polynomial time) is an unsolved problem in theoretical computer science, and is considered by many theoretical computer scientists to be the most important problem in the field.

A proof that showed that P ≠ NP, while lacking the practical computational benefits of a proof that P = NP, would also represent a very significant advance in computational complexity theory and provide guidance for future research. It would allow one to show in a formal way that many common problems cannot be solved efficiently, so that the attention of researchers can be focused on partial solutions or solutions to other problems. Due to widespread belief in P ≠ NP, much of this focusing of research has already taken place.

Yes, P ≠ NP is the expected answer, yet there is no accepted proof for that. It will be very interesting and lucky for us to witness an important milestone in computer science if Deolalikar’s claimed proof is found correct and approved by the computer science community. I think acceptance or rejection will take some time, and I’ll be waiting impatiently.

Update Jan 20th, 2011: Today I’ve seen a new work that claims P = NP with a Polynomial Algorithm for Boolean 3-Satisfiability Problem by Vladimir Romanov. http://romvf.wordpress.com/2011/01/19/open-letter/

Written by Volkan TUNALI

August 9th, 2010 at 5:45 pm

Blekko – A Brand New Search Engine

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blekkoI guess it is very likely that you use Google everytime you need to search for something, and sometimes the others like Yahoo, Bing, etc. This is what I do. Google has been my very first choice for a long time. I very very rarely use Yahoo or Bing. Now, there is a newcomer to the field: blekko.

Blekko is in a private beta stage and it is not open to everyone’s use. You need to get a join link from blekko through twitter or facebook.

I’ve just joined to blekko and actually have not tried it thoroughly. The most distinct property of blekko is the search using slashtags. Slashtags are the keywords that appear after a slash, which makes the search results narrow down according to the tag. Slasthtags are defined by blekko as:

Slashtag search lets users slash in what they want and slash out what they don’t. Knock out the spam sites and search only the sites you want to search.

Use of slashtags are very similar to the command line parameters passed to the programs in DOS.

I think I need more time and more trials to get the idea. Who knows, blekko might become my first choice search engine soon.

Written by Volkan TUNALI

August 9th, 2010 at 10:08 am

Short Movie: Java 4-ever :)

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As a software development professional, I am never a fanatic of one platform or one tool. The choice always depends on many factors and constraints. The most important thing, I think, is not the tools you use to solve the problem of the customer. Customers usually do not know about them at all. Customers usually expect good, effective and timely solutions.

I’ve found a short film about Java vs. MS .Net. It’s very funny. :)

If you can’t see the video you can visit http://www.youtube.com/watch?v=Oo-cIGVaOYE

Written by Volkan TUNALI

July 27th, 2010 at 4:56 pm

Turkish Deasciification

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Deasciification is the process of converting text written with only ASCII letters to its correct form using corresponding letters in Turkish alphabet (or any language that contains non-ascii letters). For example, the text “Cok yogun bir calisma ve emegin urunu” conveys the meaning, that is, human intelligence is able resolve ambiguities (if any) and understand text like this. The text, however, should be written as “Çok yoğun bir çalışma ve emeğin ürünü” (in Turkish). This is what a deasciifier is supposed to do.

Well, why do we need deasciification? We may not have Turkish letters on the keyboard (or the OS we are using may be without Turkish keyboard layout) and we need to end up with a text in correct Turkish form. It is also possible that we are accustomed to typing only with Ascii letters for some reason.

In addition, we may need to analyze a large collection of Turkish documents, and this collection can be contaminated with text written in Ascii, which will degrade the performance of our analysis. Then, the only possibility is to use deasciification. This is the most important reason for me as I often perform text mining on Turkish document collections, and I always need deasciification.

In this post, I’ll shortly review a few deasciification tools developed with several languages.

The first deasciifier is the one which is part of Zemberek project. Written completely in Java, Zemberek is an open-source general purpose Natural Language Processing library and toolset designed for Turkic languages, especially Turkish. A web-based demo of Zemberek is available at http://zemberek-web.appspot.com/. I usually use the deasciifier of Zemberek in my text mining research when I work with Turkish text datasets.

The next deasciifier is developed by Gökhan Tür at Sabancı University. More information and a demo is available at http://www.hlst.sabanciuniv.edu/TL/deascii.html. This system is currently not open-source, and not available for download.

One deasciifier is from Deniz Yüret at Koç University, which is actually developed for Emacs for realtime correction of words written in ascii form. More information and download is available at http://denizyuret.blogspot.com/2006/11/emacs-turkish-mode.html.

Yüret’s deasciifier is converted to Javascript by Mustafa Emre Acer, and available at http://turkce-karakter.appspot.com/.

The last deasciifier, recently published by Emre Sevinç, is a conversion of Yüret’s work into Python. More information and download is available at http://github.com/emres/turkish-deasciifier.

None of these deasciifiers is perfect, but they all perform pretty well for most of the situations. I’m sure we’ll see much improved deasciifiers with the advances in NLP studies for Turkish.

Written by Volkan TUNALI

July 23rd, 2010 at 7:52 pm