Traditionally, scientific research used two distinct methods: experimentation (or observation) and theory. However, recently, scientific computing is establishing itself as a distinct third method for scientific research. In this methodology, a computer model is created of the system being studied. The model is then tested, or validated, to ensure that it behaves like the system is it meant to replicate. This is carried out by comparing the results obtained from the computer model with real life measurements.
[attach id=690509 size="medium" align="right"]Top: Lateral view of the Hypogeum produced from the computer model. Middle: Relative humidity variations inside the Hypogeum obtained from the computer model. Bottom: Temperature variations inside the Hypogeum obtained from the computer model.[/attach]
Once a computer model is created and validated, it is then possible to carry out virtual experiments. There are a significant number of advantages of this methodology. Possibly, the most obvious is cost. In fact, in general, it is much cheaper to carry out a virtual experiment on the computer model than on the real system. Frequently, it also turns out that the virtual experiment takes much less time than a real one. Thus, the use of computer models is very cost effective, justifying on this account the use of the methodology.
In the case of a heritage site, computer models offer an additional advantage: they are non-invasive. This means that the site can be studied without the need of carrying out any experiment that can endanger its conservation status. The model would also allow researchers to investigate how external factors, such as the presence of people or the change in the ventilation system, can affect parameters that are linked to the deterioration of the site. Thus, the effect of any planned change at the site can be studied well before it is implemented.
In view of these considerations, a team of researchers from the University of Malta, in collaboration with Heritage Malta, have set up a computer model of Ħal Saflieni Hypogeum. Apart from being one of Malta’s World Heritage Sites, the Hypogeum is possibly the most delicate historical place found on the islands. In fact, the number of visitors allowed every day is limited to 80 visitors who spend 35 minutes within the site. Thus, it is the site that at the moment stands to benefit most from the setting up of a computer model.
Measured data at the hypogeum was used both as input to the model and to validate the output. An example of the results obtained is given in the figure. Comparison between the measurements and the simulated results showed general good agreement indicating that the model can be used to carry out virtual experiments. Thus, a new tool has been acquired that can be employed in the conservation efforts aimed at preserving the hypogeum for future generations.
A summary of the work has now been accepted for publication in the Journal of Cultural Heritage. The details can be found at https://www.sciencedirect.com/science/article/abs/pii/S129620741830390X .
Did you know
• For large computational tasks, in general, dividing the task over a number of computing nodes working in parallel decreases the time required to generate the result. However, as the number of computing nodes increases, the reductions in time decreases.
• The 2013 Nobel Prize in Chemistry was awarded to Martin Karplus, Michael Levitt and Arieh Warshel for developing and applying numerical methods to simulate the behaviour of molecules.
• Nowadays computations are also used extensively in financial institutions to predict the fluctuations in the financial market. The methods used are very similar to those used in scientific computing.
• Malta boasts three World Heritage sites, namely, the Ħal Saflieni Hypogeum, the City of Valletta and the Megalithic Temples. There is also a list of seven other tentative sites that can potentially be nominated as World Heritage Sites.
For more trivia, see: www.um.edu.mt/think
Sound bites
• Symbolic computing: There exists a class of computer languages that work with symbols rather than with numbers. These are meant to manipulate algebraic expressions in order to obtain exact solutions – in contrast, programmes using numbers are generally limited in the accuracy of the result by the accuracy of the computer used. The first practical implementation of symbolic computing dates back to at least 1953 with the work of J. F. Nolan at the Massachusetts Institute of Technology and H. G. Kahrimanian at Temple University. Since then, the field had flourished and currently there are various software packages that are able to carry out extremely complex mathematical symbolic calculations. This has changed the way many scientists work out mathematical calculations: they programme the equation that needs to be solved and let the software do all the dirty work. The advantage of this is that problems can be solved in much less time and there is greater confidence that the solution is free from error.
• Smartphones as portable medical diagnostic devices: Smartphones have already changed our lives in many ways. As a portable connection to the internet, they provide instantaneous access to information and altered the way we interact with other persons, just to mention a couple of changes we are all well aware of. Now, smartphones are set to become portable medical diagnostic devices. Developers are applying advanced artificial intelligence algorithms on measurements made by sensors to create apps for smartphones that are able to make medical diagnoses or to monitor a patient remotely. While some apps use additional gadgets, developers are increasingly relying on sensors already found on the smartphone. Thus, smartphones are increasingly assuming the functionalities of Star Trek’s Medical Tricorder!
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