Yet another motivation letter for PhD to revise

Hi all
I am a new members of this community, I see some of others motivation letter and get ideas from some of them but i want to make sure i write it correctly also i have question:
Is it necessary to add additional part to my motivation letter? Do you have any idea?
Thanks
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Dear Dr. XX,

I am writing to apply for a PhD position in XX.
In 2009 I received my Bachelor of Science degree in Software Engineering at XX. I have done my bachelor thesis in Online Handwriting Recognition (Distinct Letters) using HMM based approach to sequential data classification and I also present a paper on my thesis. At present I am completing a Master of Science in Artificial Intelligence at XX University of Technology, which is one of the most famous universities in Iran. My Master of Science thesis is about XX under supervision of Dr. XX at YY Laboratory and I expect to be graduated by January 2012.

I have a strong interest in statistical machine learning and their application to Natural Language Processing and Speech Processing. My background includes studies in statistical pattern recognition, machine learning and statistical natural language processing and I also have extensive experience in programming (Matlab, C/C++, C#).

My study of Artificial Intelligence led me to become interested in machine learning methods especially using statistical techniques. I am especially interested in developing new methods for applying machine learning techniques.
For me, one of the most prominent personal reasons for continues my studies are my enjoyment of collaborative research, learning new things and experience with machine learning methods. Also it seems like the perfect opportunity for me to gain practical experience in team working.

Thank you for your consideration, and I look forward to your acceptance,
Yours sincerely,