Yooin Choi


Computer Science

Place of employment

Nomura Research Institute (NRI), Global Distribution Systems Department

Hometown: Kyoto, Background: Admitted to the University of Aizu School of Computer Science and Engineering in 2004, and now working for NRI, following completion of the University of Aizu Master's Program.Attractive points of the Aizu region: starry sky and autumn leaves

Faculty's Message - Computer Science

Foundation of Computer Science Laboratory
Takafumi Hayashi, Professor

For us to share diversified knowledge and findings, for example, ideas and theories, with others, we first have to make such "understanding" objective, abstractive and systematic. No matter how excellent your idea is, it will be useless to other people unless it is objectified, abstracted and systematized. Computer science is an area of study to work on ideas for realization of various computer functions from scientific perspectives.

What you are to learn in this field will surely be of practical use for you to share your future discoveries and ideas with people all over the world and in future generations, as well as to make use of various "understanding" existing worldwide including that attained in the past.

In addition, wide-ranging contents of computer science, which have supported improvement of computers, will be an important clue for development of future generation computers.

The ultimate goal of this field is to have students acquire perspectives necessary for development of innovative and better computers. "Computer modeling" includes theories and approaches necessary for constructing the real world virtually on computers. By constructing the real world virtually on computers, we can simulate and visualize various phenomena.

For computer modeling, we first have to understand a phenomenon for modeling, and have to abstract and simplify the phenomenon for implementation on computers. Computer modeling technology is necessary for synthesis of photo-realistic computer graphics, weather simulations, visualization of social phenomena, and simulations of physics phenomena. A good balance between two aspects, "implementation on computers" and "further improved reality of the virtual world" is one of the most important aspects of computer modeling.

Any finding or idea about computers cannot be comprehensible to others without description. So does natural science to natural phenomena, computer science clarifies and describes various matters regarding computers. In addition, an extensive amount of computer science-related achievements will give us guidelines when we work on development of new computers. Ever and fast evolving computer technologies and wide-ranging computer-related areas may require you to change your career/path in the future. But even in such cases, the "fundamentals" you acquired through learning computer science and computer modeling, etc. will surely help you.

From my experience, I, who changed research themes and directions several times in the past, assure you that these fundamentals are powerful support to you.

Courses to acquire mainly

● Fourier Analysis ●Complex Analysis ●Probability and Statistic ●Applied Algebra ●Mathematical Logic ●CSE laboratories ●C++ Programing ●Database Systems ●Automata and Languages ●Advanced Algorithms ●Numerical Analysis ●Comp. Graphics ●Digital Signal Processing ●Software Eng. I

English Language Courses

Reporting Statistical Research in English

This course covers:

  1. Basic statistical research design
  2. Interpretation of results
  3. Interpreting and reporting results in English
  4. Making software that supports experimental research

Students will produce software applications that illustrate basic principles of sample-based experimental research.
Students will also report on results using standard English expressions.

Pronunciation: Comparing English and Japanese Sound Systems

This course is a contrastive analysis of the phonology and phonetics (the sound systems) of Japanese and English. Each language's inventory of sound segments will be compared systematically, as well as the syllable structure and some phonological rules. Students will be taught to produce (pronounce) and perceive the differences between sounds in these two languages. In order to assist students in differentiating between English and Japanese sounds, both ultrasound and acoustic analysis software will be used in the classroom.

Specialized Fundamental Courses (First-year students)

Linear Algebra II

This course follows after "Linear Algebra I," and deals with the eigenvalue problem. Students are required to take this course in parallel with the course, "Differential and Integral Calculus," same as the first semester. Reasons for this are explained in the syllabus for "Linear Algebra I". You will be able to understand how important roles matrices and determinants play in differential and integral calculus of several variables. Also, the eigenvalue problem tells you an effective way to solve recurrence formulae of sequences. You will also find importance of understanding organic connection between linear algebra and differential and integral calculus. This course also covers the fundamentals of vector analysis which are necessary to study electromagnetism. The fundamental policy of this course and its exercise sessions does not differ significantly from that for "Linear Algebra I".

Calculus II

This course follows after "Calculus I," and focuses on the calculus for multivariate functions. You might have an impression that the calculus for multivariate functions is different from that for single variable functions. Yet, actual calculations eventually come down to calculations for single variable functions. This means that, if you are a diligent learner who knows the importance of attending classes and, if you understand the fundamentals, the calculus for multivariate functions will be of no worry for you. The fundamental policy of this course does not differ significantly from that for "Calculus I". To better understand this course, please also see the syllabus for "Linear Algebra II."
The primary goal of this course is to master the fundamentals of calculus for multivariate functions.
The derivation for single variable functions is extended to the partial derivation for multivariate functions. However, approaches and calculations for the derivation for multivariate functions are not difficult. Do you remember that you applied the derivation to maximum/minimum problems of single variable functions? In the same way, you can use the partial derivation to solve maximum/minimum problems of multivariate functions.
Similarly, the integral for single variable functions is extended to the multiple integral. However, approaches and calculations for the integral for multivariate functions are not difficult, either. What I would especially like you to master in this course is "variable transformation," which is equivalent to the partial integral for single variable functions.
"Series" is the final topic in this course. It should be noted that the field of "series for function terms" is a basis for Fourier transformation and complex analysis.

Specialized Courses (Second/Third-year students)

Fourier Analysis

This course follows after calculus courses in the first year and focuses on "Fourier analysis," a fundamental element of analyses. Fourier analysis has its origin in Fourier's research on thermal conduction. Also, Fourier analysis has its ideological origin in Pythagorean music theory. Fourier analysis involves research on fluctuation of lights and sounds and has been widely applied to science and engineering fields. Fourier analysis (including Laplace transform) is critical to computer science as well, when you study system theories, signal processing and information communication theories. Without studying Fourier analysis, we would never be able to deal in these topics from academic perspectives. In Fourier analysis, signals are recognized as a layer of many sine waves, and algorithms for engineering application to images and waves are classified as digital signal processing. In the history of mathematics, Fourier analysis, as well as complex analysis, was important part of driving force for bringing modern analyses into life. Fourier analysis is often used for computation of functions of complex variables.

Mathematical Logic

The course starts with an introduction to basic logic and set theory including Boolean algebra. Applications such as elementary circuit design are discussed. The course continues with extending basic logic to fuzzy logic, a very modern branch of logic. Applications such as pattern restoration are discussed. course finally focuses on the formalization of theorems and proofs as another extension of basic logic concepts.

Revisit Boolean algebras and applications as a foundation of this course. Learn fuzzy logic and fuzzy set theory. Learn formalization of mathematics, in particular, proofs which then can be processed by machine.

Research Themes (Fourth-year students)

Research Theme:
  • Efficient Downsizing for e-Government in Japan(Graduation Thesis)
  • Social Networking Service for Local e-Governments using Cloud Computing and Content-aware Networking(Master's Thesis)

My research at the University mainly focused on "e-Governments."
This theme is in the "multi-disciplinary area" and involves many disciplines including not only "computer science" but "economics," "jurisprudence," and sometimes "international relations." An approach of "how the existing problems can be solved by cutting-edge IT technology" attracted my research interest.
As you know, both the national government and municipal governments are facing serious problems. I placed my research focus on the point that "whereas the population of Japan will continue decreasing until the year 2050, the amount of national debt will continue increasing, and given these situations, how the nation can establish the strength to compete internationally."
Several countries have successfully solved their problems through full use of information technology. However, we cannot guarantee that simply applying those successful cases to Japan will work out. Why? Because relevant systems including social systems, differ between Japan and those countries. Therefore, I worked on my research through multiple approaches, such as "to support solution of problems with information technology," and "to support solution of information technology problems with systems.

While taking into account all those aspects and trends in IT, I continued searching reality-based solution for the aforementioned problems.
One of the important missions of e-Governments is to promote formation of knowledge-based society in local regions as part of local infrastructure. From this perspective, I did research on integration of diversified information (or knowledge).
ss In my bachelor's research, I proposed a strategy, which is more efficient than the conventional downsizing, in order to make good use of the cost. In my master's research, I extended the scope of research further to "difficulties in responding to security issues as social needs," and "decreasing the damage of spam mails for efficient business." Both of these papers are on computer science and engineering, but they are not overly technology-focused. They are also of social value.

Flexibility is an advantage of a young university.

I can tell you many good points of the University of Aizu, but at the same time, I must tell you that it also has unsophisticated points due to its short history. Conversely, this means that the University of Aizu has flexibility which allows you to create new systems and atmosphere.

Partly because of a high employment rate among undergraduate students, there used to be a limited number of students who proceeded to the University of Aizu Graduate School. Most of the students decided not to proceed to the Master's Program without carefully thinking their career paths. Under these circumstances, I felt compelled to take action for making opportunities for students to seriously consider their future paths, and to help improve our graduate school to attract many applicants. I made many proposals for improvement, such as "starting an SCCP for thinking future paths," and "consultation service for students planning to proceed to graduate schools." Not all of those proposals were successful, but some are still in operation, even though I left Aizu.

It was also fortunate that I learned "managerial perspectives" and "importance of seeing a different view of a situation" through my work experience as a teaching assistant (for classes and exercise sessions) and a computer system management assistant for the University of Aizu Information Systems and Technology Center (ISTC). Most part of such experience owed much to the university's being a small university in size.

I think that the policy which has been pushing the university forward is "Ask, and you shall be given." As an alumnus of the University of Aizu, I hope that this policy will continue hereafter.

Job-seeking Activities

Job-finding Activities and My Current Job

Nomura Research Institute, Ltd. (NRI)
NRI was founded in 1965 as the first private think-tank company in Japan. In 1988, NRI and Nomura Computer Systems were merged. Business of NRI ranges from management/system consulting, financial/industrial system architecture to IT outsourcing.

Fortunately, several companies offered positions to me in spite of the difficult employment situations at that time, such as "recurring employment ice age," and "centennial waves of economic depression."
I chose two companies as candidates and finally made up my mind to go to NRI after thinking it over and over. If people had heard this problem, they would have got jealous to me. But most of my classmates in the Master's Program were in similar employment situations.

I enjoyed job-hunting activities, during which staff in charge of personnel affairs at several companies contacted me in person via e-mail, etc. and invited me to their private-time activities. I think it is one of the advantages accorded to students to approach multiple companies to ask for explanations. Visiting alumni working for companies would also be helpful, as you can hear direct opinions of "those actually working for relevant companies." I would also like to stress that "what you really want to do at your future workplace" is more important than "just gaining employment." When searching employment, you do not have to be specific on your areas of specialty or research themes. I would like to recommend you to think, from time to time in your every-day life, what you want to do in your future, and what you should do to put your thoughts into practice. Of course, you do not have to narrow the possible approach to one. But it will help you making your job-hunting activities more satisfactory to you.

At NRI, I have been working in Global Distribution Systems Department. All of our customers are overseas firms, to whom we provide computer system support. Communication with customers is of course in English. I am proud that our systems support business of far-away overseas firms.

When I chose my workplace, I was not so particular on IT industry. However, what I studied at the University of Aizu, including computer-related knowledge, English, in addition to my research on solution, will continue being great support to me.

Other Cases


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