Well, you forgot to take into account the 'time delay' between the moment you turn the hot water tap and the moment the hot water actually starts coming out! This is an extremely simple example to illustrate the problem of controlling a system with time delay, with you as the controller and the objective of obtaining water of the right temperature. You measure the current water temperature, take a control action which in this case was turning the tap accordingly. We can see that the presence of the time delay makes the problem more difficult.
Control of systems with time delays is the research project of Agoes Moelja, an Indonesian Ph.D. student in the Systems Signals and Controls group at the EWI faculty. Agoes explains, 'time delays occur naturally in many physical systems. Measurement lags, communication lags and analysis time are the main causes. Time delays complicate the analysis and design of automatic controllers and make satisfactory performance a
quite hard to achieve.' The theory developed in his research has a wide range of applications - chemical process control, water treatment plants and steel strip mills among others.
After graduating in Electrical Engineering from Bandung Institute of Technology, Indonesia, Agoes came to the Netherlands on a scholarship to pursue a Master's in Applied Mathematics. Thereafter he was offered a Ph.D. position and he is currently in the second year of his research. Never having left his hometown Bandung, Agoes looked forward to coming to the Netherlands. 'It is fun' he says, 'to live on my own. It is also enriching to meet people from different countries and cultures'. According to him Dutch people are very friendly and straightforward, though quite individualistic unlike the people in the Asian culture he grew up in.
Since Indonesian food is quite popular here, Agoes did not have to alter his eating habits drastically. He has also grown to like Dutch cuisine, his favourite being 'stamppot'. Communicating with the locals did not pose any problems, since Agoes found most people to be quite proficient in English. He has himself been taking Dutch lessons for the past six months.
The future? - after completing his Ph.D., Agoes aspires to remain in academia, maybe to pursue a post-doc, preferably in the Netherlands.
Name: Agoes Moelja
Hometown: Bandung, Indonesia.
Languages: Indonesian, Sudanese, English, Dutch (in progress)
Favourite food: Nasi Goreng
Favourite movie: Dead Poets Society.
Favourite sport: swimming (since he was seven years old)
Favourite music genre: pop (The Cranberries)
Favourite place in the NL: Museumplein in Amsterdam.
Best part of being in the NL: meeting his girlfriend (They get married inJuly)
Worst part of being in the NL: closing hours of shops.
Dream destination: Japan.
Hobbies: traveling, swimming, watching movies.
Favourite book: Indonesian books/novels, books with historical background.
