During my undergraduate study, myocardial infarction (MI) has taken away three people I know:
one of my uncles, a friend of my father, and a fellow student in my college. Sorry for their loss, I
start thinking methods to prevent it. Although it is acute when happens, several deterministic
changes in electrocardiogram (ECG) can indicate a large probability of MI several days before it
takes place. Thus proper monitors can be a life-saving tool. However, current ECG machines are
large and clumsy due to build-in processing unit and display. We can greatly reduce its size by
transforming it into a peripheral of mobile devices, which is responsible for data processing and
display, and elongate its duration. During my graduate study, I want to focus on two aspects:
efficient coding standard of ECG wave and anomaly detection and transmission hardware design.
Current PCM based coding leaves out periodicity and structure characters, which is exploited in
wave-based coding. In most cases, even heart rate slightly varies, PR and QT interval of ECG
remains unchanged across heartbeat, thus we can code the first one with PCM then record only the
start time of P wave. Otherwise, only the duration and/or magnitude in changed waves or intervals
are recorded. And Difference PCM and run-length coding techniques can be used. Besides,
characteristics of different waves call for different sampling rate and quantization step size. For
example, a coarse sampling rate and fine grain quantizer can be deployed because P waves lasts
relatively long with low amplitude. However, in QRS complex, a high sampling rate is necessary
due to rapid change in voltage, and nonlinear quantizer is useful to reduce bitrate for positive
segment. Thus encoder, usually in body wearing devices, can greatly reduce amount of data while
maintaining high accuracy, which makes possible for long-time monitoring.
In addition, extremely low power transmission is necessary to prevent potential hazard to human
body. Minnesota Code (MC) Classification System provides a well-defined anomaly report
method with a maximum of 12 bits for each case, which guarantees the possibility of low power in
transmission. Besides, detection methods in MC can be grouped into amplitude and its ratio,
duration, pattern in lead, axis deviation, slope and rate monitoring. Each of them can be
implemented with specific circuit components. Together with wave detection circuit, a compact
but robust anomaly detection circuit can be designed. However, optimized hardware reuse and
delicate logic design are essential to low power consumption of IC.
I’m confident to carry out my research plan because my undergraduate study has provided me
with a thorough foundation of knowledge and ample experience of research. As student of Chu
Kochen Honors College, which is a prestigious program gathering top students in Zhejiang
University, I have earned 25% more credits on a wide range of topics with an emphasis of
mathematics, hardware, signal processing and programing, while maintaining an outstanding GPA
and ranking in the top 5%. And I pay more attention to practice than grades because any grind in
practice is beneficial, and the denoted time and energy now will pay off for my career. In Lab
Work for Digital Systems Design II, the control unit of my Verilog multi-cycle CPU could not
function properly. For a whole week, I checked module codes with their circuit block diagrams,
analyzed output waveforms, and finally observed that the Z(zero) signal from ALU was one period
delayed due to its synchronization circuit, which could be replaced by a reg type of Z.
Besides, I have grown a keen interest in research during Student Research Training Program
started in my sophomore year. I aimed to design a structure to implement anisotropy with isotropic
materials, and the desired anisotropy can implement infinite large ground-plane electromagnetic
cloak. Recent publication mentioned no experimental results because structures were beyond
manufacture capability; therefore I proposed to design and fabricate a block of PCB with rigid
array of elliptical through-holes and experimentally test my result. After calculating intrinsic
parameters (permittivity and permeability) using space transformation and verifying them in
COMSOL, I simulated over a hundred of structures in CST for S parameters and solved for
intrinsic parameters in Matlab. However, all designed structures would cause resonance of
photonic crystal closed to target frequency, i.e. no desired cloak can be achieved.
Though results were unsatisfactory, I found course study is a casual journey, while research is a
thrilling exploration. I learnt that research requires different skills from course study. To promote
them, I participated in 2012 Mathematics Contest in Modeling. The four-day contest asked us to
build a mathematical model for leaf description and classification, and to submit an essay with our
findings of leaf shape variation and leaf mass estimation method. But after two days, our work
only focused on cell-level veins and could hardly solve tree-level problems. As the team leader, I
decided to drop minor factors such as carbon dioxide but focus on water transportation in leaves
and observe its effect on leaf growth. It was a risky move considering the time, but it turned out to
be a success. We illustrated our answer in a 50-page essay and our model, supported by data and
research conclusions from 27 papers, explained how leaf shape is influenced by water supply
pattern, which is closely related to genetic and environmental factors. Not only was our work
designated as Finalist (Top 27 among 3697 teams), but I also improved my abilities in field
research, scientific writing, resolution and leadership.
Moreover, I realize programming is prevalent and essential for research and industry. Thus I took
extra courses on Data Structure, Objected Oriented Programming, and became fluent in C, C++
and Matlab by practicing them in course projects and research. Besides, I’m learning Python by
taking a course at Coursera. These experiences not only sharpened my programming skills and
deepened my understanding of language, but also strengthen my ability to handle complex
programs. I deepened my comprehension of top-down approach when working on Nonlinear
Disparity Mapping for Stereoscopic 3D. I should build a main framework, and then optimize each
part, because proper output can help with evaluation of improvement in the code. Moreover,
through my research, I realized developing research abilities is similar to learning photography:
first I should master the basic knowledge like exposure and composition, learn and emulate others’
work and practice frequently, and then some amazing shots will come up. A thorough knowledge
foundation, familiarity to current work, diligence and creativity are vital to researcher, and I’ve
make great efforts to equip them.
In my first summer vacation in college, I got an opportunity to participate in summer session at
UCLA. Not only did it provide me with my first glimpse of Western culture, but I was also
exposed to a different academic environment. I fell in love with it and decided to pursue graduate
study in a top American university. And I’m now taking several Coursera courses because I love
western teaching styles and they’ve brought me great joy and useful knowledge. Thus I’m
applying Ph.D. program in Electrical and Computer Engineering with an emphasis in Computer
Engineering. I’m enthusiastic about this program for several reasons. First, Prof. K.T. Tim Cheng,
whom I met in September at Zhejiang University, is interested research on mobile health, and he is
an expert in VLSI. I want to be his student to learn and conduct research with him. Secondly,
graduate courses cover a large variety of topics from VLSI to signal processing and
communication, which are essential for my research. Among them, I’m particularly interested in
Mobile Embedded Systems, Advanced VLSI Architecture and Design and VLSI Digital Signal
Processing. Moreover, as a shutterbug, I cannot resist the beautiful campus of UC Santa Barbara.
And extensive biking system in campus—ubiquitous exclusive paths, stands and lockers—greatly
appeals to me because cycling is my favorite exercise.
To better prepare for my graduate study, I’m working on a real time HD video transmission system
on FPGA, through which I can enrich my knowledge and experience in hardware system design.
Thus I feel I’m qualified to your program and sincerely hope you can favorably consider my
application.