Q. Could you briefly introduce the research that your team has been doing?

I think our research field these days can be mainly divided into the field of optimal design and the field of ultrasonic metamaterials.
In the field of optimal design, the design target is a rigid body-based mechanism. For example, refer to mechanical devices such as 4-bar links and 5-bar links. They are essential in places that require mechanical motion, such as cars and robots. Engineers are always being asked to creatively design mechanisms with better and newer functions. However, it is not easy to design creatively with your own design experience or trial and error method. Even if there is no initial design plan, ifly the problem to be designed is precisely defined, that is, if the desired output motion, etc., is accurately described, then wouldn't it be nice to have a technology that autonomously designs with a computer algorithm? Our lab presented the world's first automatic design methodology that can do this, and we are demonstrating the usefulness of that technology by actually implementing a product with that technology. This field has not been attempted by others, and it can be said that our laboratory pioneered a new field of study.

And I would like to briefly introduce the field of ultrasonic metamaterial research. First of all, most of you probably know that ultrasound is used notly for medical purposes but also for industrial purposes. To give an industrial example or two, it is precisely measuring thickness with ultrasound and finding fatal flaws hidden in structures. In fact, in order to use ultrasonic waves well in actual applications, we need to be able to handle the size, direction, and mode of ultrasonic waves at the desired level, but current technology has limitations. That's why it's difficult to dramatically advance the ultrasonic rider. So, in our laboratory, we are conducting research to overcome these limitations by using a new concept called 'metamaterial'. When a ship is submerged in water like the Sewol ferry and cannot see the inside, if you use the metamaterial-based ultrasound technology being developed in our lab, internal imaging is theoretically possible. I think metamaterial research is very attractive in that it can overcome the limitations of current ultrasound technology.

Q. As you said, you have been conducting various studies for a long time. What was the most memorable research?

I think all research is meaningful. It is difficult for me personally to choosee because research does not end with any topic, but continues to develop.

Q. Then, what was the most difficult part of your professorship career?

In my early days, it was difficult to get research funding, so I had a lot of trouble. There is a big research project called a creative project that an individual does independently, and I wanted to do that business in my early days as a professor. Unfortunately, I couldn't be selected at the same time, so I suffered a lot. Even at that time, to do the creative project task, I had to sort out all the other tasks, but there was a time when creative business tasks could not be selected atce, so there was a time when the operation of the laboratory was very cold. However, fortunately, I was lucky enough to do the creative business project, and after that, I was able to research stably.

So, from the professor's point of view, I think it is very important to do good research to secure a research project with a certain amount of research funding that can be conducted over a long period of time. Of course, more importantly, passionate and talented students who work with a clear will to do good research. However, there is virtually nothing you can do without research funding.

As a professor of engineering, there are things that I envy of professors who do natural sciences in terms of research expenses. In that field, there is a research support system called the Institute of Basic Science (IBS), which is supporting the research center with a very large research grant. I am very envious of the fact that if a large research fund is secured, an environment in which research can be conducted much better. IBS is to nurture scholars who will receive Nobel Prizes. There is no Nobel Prize in the field of engineering, but good research that is comparable to, or maybe even more than, the Nobel Prize can come out, right? I wish this could be improved a bit.

Anyway, there were times when it was difficult because there was no research funding, but there was a research I wanted to do, and I was fortunate to be able to start a creative business because I had the will to complete the assignment. Through the 9-year project, I was able to do well in the research I wanted to do and actively engage in international exchange activities. As a result, I think my research skills have been recognized internationally.

Distinguished Professor, A New Beginning

Q. It seems that your hard work in research was recognized as a distinguished professor in September of this year. Did you have any feelings or expectations as a distinguished professor?

I think that I became a distinguished professor because my research has been internationally recognized. In addition, I want to share the know-how that I have accumulated during my research activities with many researchers in our country. If many researchers can minimize unnecessary trial and error by using such know-how well, wouldn't it be very helpful for good research? By sharing know-how, I want to provide a foundation for more Korean researchers to conduct world-leading research in a faster time. So, I'm trying to make a video of this material. For example, how graduate students should do research, their attitude toward research, how to write a thesis or how to present it. There are quite a few things I want to tell other professors. I hope these things will be of practical help.

Q. So, what advice would you give to graduate students or undergraduate students entering the Department of Mechanical Engineering?

학이불사즉망(學而不思則罔) 사이불학즉태(思而不學則殆)
"To study and not think is a waste. To think and not study is dangerous."*

This is a phrase from the Analects of Confucius, Weijeongpyeon (爲政篇). If I interpret this, I will learn, but if I do not think for myself, I will be locked up in the academic world of my teacher and I will not be able to expand my academic world.
As a prime example, let's say that some people created something that violates the laws of conservation of energy in thermodynamics. They thought a lot, but knew nothing. So, you can have vain delusions and waste your life.

Conversely, if graduate students have a meeting with their advisor andly do what the professor tells them to do, they will be stuck in the world of the advisor and will not be able to develop their studies. What a professor knows is already known knowledge, isn't it? So students have to think for themselves. But as long as you do it, it's literally 'mang'. There can be no good research. After that, graduate students think a lot, so they have a lot of ideas, but if they don't study or read their thesis and don't listen to their advisor, they're in danger.

The best way is to prove that you can't do it when the professor tells you to try it, and then think for yourself and think about what to do. It's true that most professors are quite right, but they don't know everything. A new study is a new study that even the supervisor does not know. I believe that a master's degree, especially a doctoral degree, can become a doctoral degree of their ownly when the professor discovers and creates something that the professor doesn't know. In that regard, I think that learning and thinking correctly is the most important virtue that every researcher should have.

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* Cyberseowon: https://m.cyberseodang.or.kr/search/todaygu_view.asp?idx=276

The interview was conducted September 24, 2021 by the Journalists of the School of Mechanical Engineering.

MEch-SSENGER Goo-Yeop Jeong, Jeong-Jin Lee