Current wr0k, Spring Break, exams and etc.

Lately, I have been enhancing the web service that I have been working for a while. Developing web services using C#.Net is really easy and fast. I have built documentation using Doxygen for web service invokers.

Yet another project I m working on is populating data of an application and saving the results in a data warehouse. So that Pentaho will analyze the data and generate reports.

I m almost done with another project for Huge Inc, which is a Flex FTP Client.

School is in Spring break. Last Thursday I had two midterms on the same day which was a disaster. from 9.30 am to 2 pm. Certainly, the PhD program could schedule better exam dates. :-/

Writing a paper on data center network design. Interesting topic. Not easy.

C# Empty StringBuilder, empty content of StringBuilder (C-Sharp)

StringBuilder is mutable and sometimes you want to empty StringBuilder, in other words you want to clear the content of StringBuilder object . Here s how to do :

StringBuilder sb = new StringBuilder();


// Do something else

// Empty the content of StringBuilder

sb = new StringBuilder();

A Security note on Cloud Computing

Here goes a hacker and cloud computing :

Hacker sparks an cloud instance and installs bunches of software and programs, such as email servers, dns servers, builds a system, then start spamming and attacking users. After an amount of time, hacker kills the instance, leaving almost no fingerprint behind.

I imagine Amazon and Microsoft would be keeping record of instances, IP addresses and logs but it s also difficult to do this.

Therefore, Cloud Computing need strong security policies and implementations.

Similarity measures for categorical and numerical patterns

Today, Professor Wei talked about similarity measures between matching and recognition purposes in information systems. Professor started introducing algorithmic approaches such as dynamic programming, linear programming and edit distance.

Professor Wei talked about Edit Distance algorithm, how it works and what it does and introduced Markov Edit Distance algorithm which is another approach of edit distance algorithm to process the similarities of different objects. Edit distance is an important algorithm that is being used by many researches for string and other objects searching similarities, mismatches and differences.

Kolmogorov complexity was also mentioned in the talk which is related to information theory, compression and presentation of data. For example: printing out 1 million 0’s can be done by writing them in a loop which the loop invariant would run 1 million times and print 0. The amount of information is same but it s presented with less information.

Professor Wei, also talked about use of histograms which are not any longer applicable therefore there s been a new development of local sum algorithm that is used to for swapping, splitting, merging and differing quantization schemes in case there is some noise. Professor showed us image examples which were processed and different results were produced using local sum algorithm.

What Every Computer Scientist Should Know About Floating-Point Arithmetic

This is an amazing paper about floating point arithmetic and actually while I m programming, there have been several cases that I to deal with the nature of floating point numbers, eg: unexpected results from floating point calculations

C# Parsing URL from a string

Here is an easy to way to parse URL and process the components of a URL.

string url = “”;
System.Uri uri = new System.Uri(url);

// get the host name (
string host = uri.Host;

// get the protocol
string protocol = uri.Scheme;

// get everything before the query:
string cleanURL = uri.Scheme + “://” + uri.GetComponents(UriComponents.HostAndPort, UriFormat.UriEscaped);

You can get the components of a URL like this.

Developing new Metrics for computer based multitasking behavior

Firat Atagun

Research Seminar

Talk 5

Developing new Metrics for computer based multitasking behavior

In this talk Professor Raquel Benbunan-Fich, presented new metrics and approaches to investigate computer based multitasking behavior. Multitasking is a fundamental behavior in our everyday life. Understanding multitasking and efficiency is the challenge and this talked presented some approaches taken against this problem. This research is interested in finding metrics of multitasking unrelated computer tasks.

The metrics are calculated using self reported user logs by about 50 users and these logs are being parsed and analyzed to metrics are created. A program has been developed by a PhD student in Perl language and upon installing in the user’s computer program traces the windows and activities of users and records them as log files. These log files later are being parsed and processed and metrics are being generated and analyzed.

This talk was lays the foundation of human computer interaction based on 3 elements: user, task and technology. Moreover, overlapping of the tasks is also being analyzed and processed.

One of the interesting point I realized it that multitasking and task switching resembles context switching in processors. One of the important aspect of context switching is that it s an expensive operation in the sense that there needs to be several operations done in the operating system to switch between processes, in this model tasks. This brings up the question of efficiency in task switching and multitasking.

My interest in this research area would be to analyze the connection between the human – computer interaction and greedy algorithms. While using a computer we intent to have a greedy criterion that we derive more benefit then others, I m curious the relation between greedy algorithms and human-computer interaction. Moreover, if the user behavior is learned by computers we might develop intelligent agents and operating systems to serve the users better.