Personal Statement It is my great pleasure to recommend Mr. Cai Yan to your graduate program. I believe that Mr. Cai is sufficiently prepared for his proposed study and he will make tremendous contributions to your program with his interests for network technology and his knowledge in this area. I have been acquainted with Mr. Cai since 2001 when Mr. Cai attended my class of Enterprise Network and System Integration. I was impressed by his strong interests for network science and wide knowledge in this field. In the class, Mr. Cai was one of the most active students who often had discussions with the visiting lecturers we invited. The topics they talked with the lecturers included diverse aspects in network area, such as network security, virtual private network (VPN) and special network protocols. As the final exam of this class, I asked students to submit a paper about what they learned from this course or other ways. Among about 60 students, Mr. Cai was distinguished by his paper about Max-Plus model of TCP protocols. His paper contained lots of theories in linear algebra and descriptions of TCP protocols? behaviors. However, it was seldom for a first-year graduate student to have strong basics in both mathematics and network science. Due to Mr. Cai?s excellent performance in the class and on homework, I finally gave him a very high score of 92 on 100-grade system, and he ranked as top 4 in 62-student class. Besides, I also ever took the chair of Mr. Cai?s defense committee in 2003, and as one of three evaluators for his discourse, I was responsible to score for his graduate work. Around the central topic of ?Control Problems in IP network?, Mr. Cai extended his research into congestion control and modeling of TCP protocols as well as into discussion of the relationship between network transmission capacity and topology structure in the basis on a kind of Small World networks. Through his master discourse, it could be seen that Mr. Cai had done lots of work in network field and mastered in network science, especially in TCP/IP network. His research work included not only theoretical analysis but also practical simulation, which showed Mr. Cai was expert in utilizing mathematics tool to analyze problems and skilled in designing and programming simulation experiments. In my association with Mr. Cai, I found that he has the capability to carry on advanced studies in his field and achieve a success research career. I am very confident that he will be an excellent Ph.D student in the fields of control theory and computer network at your University. I enthusiastically recommend Mr. Cai for admission to your program and would be very pleased to furnish additional information if needed. Any assistance you could render to his application for admission and assistantship would be highly appreciated.