Successful story of an earthquake engineering expert of FST, Prof Yuen Ka Veng
科技學院地震工程學專家阮家榮教授成功之路

Prof. Yuen Ka Veng is the Dean of Graduate School, Distinguished Professor of the Department of Civil and Environmental Engineering (DCEE) and Academic Leader of the State Key Laboratory on Internet of Things for Smart City. He has held many important positions of UM in the past 18 years, including the Registrar, Head of DCEE, Associate Dean and Interim Dean of Faculty of Science and Technology. After graduating from the Pui Ching Middle School, Prof. Yuen went to Taiwan for his undergraduate studies. Four years later, he pursued his master degree in Hong Kong University of Science and Technology (HKUST). Afterwards, he went to California Institute of Technology, where he obtained his doctoral degree in only 2 years and 7 months. With his perseverance in research career, Prof. Yuen became the first UM scholar to be promoted to full professor before the age of 35 and distinguished professor before age 43. He has achieved great success in his research career.

Be diligent to prepare for the future

FST invited Prof. Yuen for a personal interview to share his academic research and successful experience. When asking the reason on why he chose his research area, Prof. Yuen smiled and said: “I didn’t have much knowledge for the selection at that time. I just knew that I liked Mathematics most.” With a clear and well-defined goal, he determined to embark on the research career when he was an undergraduate student. Therefore, he studied many graduate courses in year 4 as an undergraduate student. He graduated with ranking top 1 over more than 150 students and then went to HKUST for his master studies. He started his research work on the first day upon his arrival. Prof. Yuen is a conscientious and a hardworking person who devoted himself in research even during holiday like Christmas Eve. Compared with other postgraduate students who publish one or two papers during their master study period, Prof. Yuen has published a total of six journal papers during his master studies. He kept a straight A+ record and successfully received the offer from California Institute of Technology where he eventually completed his doctoral degree.

Studying Bayesian inference makes him an Earthquake Engineering Expert

Prof. Yuen returned to Macao in 2002 and was appointed as an assistant professor of the Department of Civil and Environmental Engineering of UM. He was promoted to an associate professor four years later. In 2010, he became the first UM scholar to be promoted to full professor before the age of 35, and in 2018, he became the first professor of UM to be promoted to Distinguished Professor before the age of 43. His specialty is Earthquake Engineering, and his work concerns with the structural health status of bridges, tower and buildings by using their vibration measurements with Bayesian inference. The structural parameters can be back calculated for health status assessment. Prof. Yuen says, ‘structural health monitoring is just like traditional Chinese medicine which determines your health level by checking the pulse. Researchers can also understand the structural health via pulse of structures.’ However, the difficulty of this problem is that there are various types of uncertainties, such as ground motion, wind pressure or even the people/vehicles loadings. When it comes to the most challenging aspects of research, Prof. Yuen says, ‘Civil Engineering structures involves too many unknowns. The construction or foundation materials, such as concrete or rock, have substantial uncertainties and there are other unknown factors like the external loadings. The Bayesian method can be used when you cannot accurately determine the essence of a thing or the value of a variable. It can help you estimate its probability (or probability density) using its response measurements. The research that really made Prof. Yuen famous is his research paper published in 2004 “Model Selection Using Response Measurements: Bayesian Probabilistic Approach” with Prof. James. L. Beck. The paper was published in the Journal of Engineering Mechanics, a flagship journal of the American Society of Civil Engineers, and this paper is the top 10 cited among more than 3,000 papers published in this journal for decades.

Set off a research boom in Bayesian methods

In addition, his single-authored monograph “Bayesian Methods for Structural Dynamics and Civil Engineering” (published in 2010 by John Wiley & Sons, a leading international publishing house) has sparked a boom in Bayesian methods for structural dynamics, which has become a classic in this field. ‘When I wrote the book, I was required to redraw every figure. I also spent a lot of time to make the text perfect and I even revised one of the chapters for more than 30 times,” Prof. Yuen says. Even the reviewers of John Wiley & Sons also admired his conscientious and meticulous. Prof. Yuen is now preparing his second and third books, which he hopes to popularize the Bayesian methods to other areas such as geotechnical engineering and air quality modeling.

Having students all over the world

Since teaching in UM in 2002, Prof. Yuen has nurtured many young talents. Some of them have become professors at well-known universities. Prof. Yuen has witnessed the growth and development of many young people. One of his outstanding students, Prof. Mu Heqing (Max) obtained his Bachelor’s, Master’s and Doctoral degrees from UM. After achieving his PhD, he was employed as an assistant professor at the South China University of Technology. Due to his outstanding research achievements, Max was promoted to associate professor within one and a half year. The papers co-authored by Prof. Yuen and Max have been published in the international journal “Computer-aided Civil and Infrastructure Engineering”, and have achieved outstanding result among more than 120 papers published in the same time, with the second most-cited record. The other outstanding student is Dr. Gilberto Ortiz who is from Colombia. In order to study Bayesian inference, he traveled across the world to UM. Ortiz’s research was successfully completed and published with the best results. He completed his doctoral study within 3 years and became the first PhD graduate of UM from Spanish-speaking countries. For teaching work, Prof. Yuen always spares much effort to guide students to participate in front-line research work. In the old campus of the UM, Prof. Yuen worked with students to monitor the East Asia Building for more than 5 years to study the impact of temperature, humidity and other environmental factors on the long-term structural behavior. They also studied the behavior of buildings under severe weather.

Advice for young people

For young people who are looking forward to research career, Prof. Yuen said that diligence is a must. “Don’t expect that you can work less hours but achieve more than the top talents among the world. If one wants to join my area, interest in Mathematics is also necessary.” ‘I have taught at UM for 18 years. I have witnessed that the younger generation is rather different from the previous. I also understand that the younger generation are under great research pressure. The world is developing in a rapid pace and people are more ambitious now.’ Prof. Yuen says. ‘I understand that nowadays young people focus more on the quantity and they want to publish more papers in shorter time span. They also want to cover more research fields. However, there are many papers produced every day in the world, and it is easy to be forgotten. You can only make an impact with substantial and sustainable work.’ Prof. Yuen says. He gave advice to young people, ‘It would be difficult for scholars to achieve results if their outputs are diluted in different fields.’ ‘You will have better chance to be successful when you work wholeheartedly on the specific area where you are good at. You can expand your areas after you become an established scholar.’

現任研究生院院長，土木及環境工程學特聘教授，智慧城市物聯網國家重點實驗室學術帶頭人阮家榮，在澳大任教的十八年中曾擔任不少重要職位，包括澳大教務長、土木及環境工程系主任、科技學院副院長及科技學院代院長等。 自培正中學畢業後，阮教授便到台灣大學升讀本科學位，再到香港科技大學升讀碩士，後來再到美國加州理工學院以僅僅2年7個月完成博士課程。阮教授憑著他堅韌的精神，成為澳大首位 35 歲前晉升正教授以及43歲前晉升特聘教授的學者。在科研路上，阮教授成就斐然。

勤奮刻苦，為未來準備

科技學院本次有機會邀請到阮教授分享個人學術研究及成功經驗。當問及最初如何選擇這研究領域時，阮教授微笑道:“當時沒有想太多，只知道自己最喜歡數學。”目標清晰的他，大學時期就決心走上研究之路，故大學最後一年特意修讀很多研究所的科目。以第一名畢業於台大後， 到香港科技大學升讀碩士。第一天，他就馬上投入到研究工作裡。而在讀碩士的日子裡，認真好學的阮教授即使在特別日子，例如平安夜也埋首研究工作。相比一般的碩士研究生發表一兩篇論文，阮教授讀研究生的時候，一共發表了六篇期刊文章。他也以全A+成績完成所有課程，最終成功進入美國加州理工學院并完成博士學位。

鑽究貝葉斯方法，成就地震工程專家

阮教授於2002年回到澳門並擔任澳門大學科技學院土木及環境工程學系助理教授，四年後便獲晉升為副教授。2010年，成為澳大首位 35 歲前晉升正教授的學者。2018年，更成為澳大首位43歲前晉升的特聘教授。他的專業領域是地震工程學，通過對土木結構 (如房屋、橋樑)測量它們的振動，再用貝葉斯方法進行反算，從而看到結構健康的情況，最終達到結構健康監測的目的。阮教授很生動地形容說: “就像中醫把脈一樣，透過結構物的脈像，從而了解結構的健康程度。難度在於當中涉及到很多不確定性，如地動或者風吹。” 談及研究上最具挑戰的地方，阮教授表示土木工程結構涉及太多未知數，地基材料如混凝土本身就有很多不確定性。當遇上地震或強風時，結構每一點的受力都不一樣，不確定非常高。而貝葉斯方法則是當人不能準確知悉一個事物的本質時，可以依靠與事物特定本質相關的反應數據去判斷其本質屬性的概率或概率密度。透過用貝葉斯方法進行反算，就可以知道結構健康狀況。而真正令阮教授成名的研究是2004年，阮教授與加州理工學院教授James Beck合著的論文“使用結構響應測量的模型選擇：貝氏機率方法”。該論文獲美國土木工程師學會旗艦學刊《工程力學期刊》發表，並於該刊數十年刊登的三千多篇論文中，引用次數名列前十。

掀起研究貝葉斯方法熱潮

此外，他的單一作者專著“Bayesian Methods for Structural Dynamics and Civil Engineering”（由國際頂級出版社 John Wiley & Sons 於2010年發行）更掀起結構動力學貝葉斯方法研究的熱潮，該書已成為此研究範疇的經典讀物。阮教授回憶道: “當年寫這本書的時候，書中每一個圖表都是重新再畫，而內文也是經過反覆修改，其中一章更看了超過30次。” 阮教授的一絲不苟，連國際頂級出版社 John Wiley & Sons的編審都忍不住稱讚。現時阮教授正準備籌備第二及第三本書，期望能夠把貝葉斯方法推廣到其他範疇，如土壤和岩石力學、及空氣污染等問題。

桃李滿天下

從2002年回到澳大任教以來，阮教授培養了不少新一代人才，部份更在國內知名大學任教，見證眾多學生畢業成長的阮教授坦言滿足感十分強。其中一位“入室第子”慕何青是阮教授的碩士及博士生，於澳大獲得學士、碩士及博士學位。在獲頒博士學位後，即獲聘為華南理工大學助理教授。由於其卓越的研究成就，慕何青僅在一年半內就獲破格晉升為副教授。阮教授和慕何青合著論文獲刊登於國際學術期刊《計算機輔助的土木和基礎設施工程》，並於同期發表的120多篇論文中脫穎而出，引用次數名列第二。另一位學生是來自哥倫比亞的 Gilberto Ortiz，是首位西班牙語系國家的澳大博士。為拜師，他飄洋過海來找阮教授，獲得啟發和清晰的指示後，Ortiz的研究得以順利開展，並以最佳成果發表，最終在3年內便完成了博士學位。對於教學工作，阮教授也總是不遺餘力地帶領學生參與前線研究工作。在澳大舊校園時，阮教授與學生全天候監測東亞樓長達 5 年，研究氣溫、濕度等環境因素對結構長期行為的影響。亦曾研究建築物在強烈颱風天氣下的行為。

給年輕人的建議

對於響往研究之路的年輕人，阮教授表示要有刻苦的能耐。“別期望自己能付出比世界上其他精英少的努力做出更好的成果。而有意進入他的領域，也需要對數學有熱誠。”他語重心長地說: “我在澳大任教18年，見到年輕一代與上一代有很大不同，我也明白新一代年輕人承受的科研壓力比較大，世界發展步伐快，所以他們也比較急進。” 阮教授留意到年輕人比較注重論文數量，希望在短時間內能夠有較多的發表數量以及涵蓋較多領域。但他表示全球每日都有很多論文產出，很容易就被埋沒了。“年輕的學者如果涉及太多不同範疇，把時間分散在不同領域，這樣很難取得成就。所以我的建議是專注在自己擅長的領域，若把努力放在一個領域，一心一意地朝研究目標進發，反而比較可能取得成功。在取得相當成就後才把領域延伸出去。