Math-Hack Day
Registration is open for the math-hack day of INTEGRATE ASG on 26 October
– Published 17 October 2016
INTEGRATE ASG is organising a math-hack day at the Pufendorf Institute on 26 October where three topics will be discussed:
- Plotting points on a single image
- Calculating safety levels of infrared radiation to the eye
- Evaluation of the interactions of physical quantities in the Earth System
All three will be presented at the beginning of the day (see programme below). People
will then split up into groups (part choice, part random, part seasonal shuffle) and discuss/work
on the topics over the day. We will all meet up again mid-afternoon when the groups will tell
us what they got up to, ideas they had and how it went in general.
We have the main lecture hall but also other rooms in the Pufendorf booked, so there
will be plenty of space to spread out.
Bring your laptops. Note that the Pufendorf has eduroam as its wifi network.
The day will be fueled by coffee, tea, and a sandwich lunch.
This will be a day for those who want to work together to solve problems.
Those wishing to attend what promises to be a fun and interesting day should REGISTER by sending an email with subject "Registration for 26 October INTEGRATE" to Melvyn B. Davies (mbd@astro.lu.se).
Note that as places are limited, you are encouraged to register early to avoid disappointment. In any case please register by 12.00 on Friday 21 October.
INTEGRATE MATH-HACK DAY -- Wednesday 26 October
Location: Pufendorf Institute, Lund University
09.30-10.00 Tea/coffee
10.00-10.05 Melvyn B. Davies -- Welcome and introduction to INTEGRATE Math-hack Day
Introduction to the topics:
10.05-10.10 Plotting points on a single image -- Alexey Bobrick
10.10-10.15 Calculating safety levels of infrared radiation to the eye -- Richard Andersson & Marcus Nyström
10.15-10.20 Evaluation of the interactions of physical quantities in the Earth System -- Minchao Wu
10.20-12.30 group discussions/work
12.30- 13.00 Lunch sandwiches at Pufendorf
13.00-14.00 further group discussions and groups prepare presentations
Progress reports:
14.00-14.20 Plotting points on a single image -- group member(s)
14.20-14.40 Calculating safety levels of infrared radiation to the eye -- group member(s)
14.40-15.00 Evaluation of the interactions of physical quantities in the Earth System -- group member(s)
15 minutes max for the group presentations + at least 5 minutes for discussion
15.00-15.30 Tea/coffee
MATH-HACK DAY TOPICS
Topic A) Plotting points on a single image
-- Alexey Bobrick (Astronomy & Theoretical Physics)
A 800x600 image contains less than a million pixels.
How to plot a dataset with a million points on such an image?
This is about sharing expertise/techniques and trying a few ideas.
We will provide a test dataset for 10^6 Gaia stars for the LMC.
Some possible ways to go: Try using points with opacities; represent points as PSFs, similar to SPH; do contour plots with average point densities per pixels colour coded.
Topic B) Calculating safety levels of infrared radiation to the eye
-- Richard Andersson (Dept of Philosophy & Cognitive Science) & Marcus Nyström (Humlab)
Many research disciplines utilize equipment for measuring where a human is directing her gaze, e.g. where on a screen, on what word in a text, and with what latency following some input. Such eye-trackers are highly used at Lund University, particularly the video-based systems. All video-based eye-tracker systems film the eye at the same time as it is illuminated by infrared light (IR-A, typically 740-960 nm), This illumination is critical to achieve high contrasts between features (e.g. the dark pupil and the bright reflection of the light source). In our work to find better techniques for tracking the eyes, we are playing with our own custom illumination. This allows us to vary the positioning of the light as well as the number of light sources visible in the eye. Of course, this is not without risk, and we are currently testing this on ourselves in very short sessions. We would like help in understanding available equations for safety levels of IR irradiance of the eye, and plug in the values from the data sheets of our currently used IR light-emitting diodes.
Topic C) Evaluation of the interactions of physical quantities in the Earth System
-- Minchao Wu (Physical Geography & Ecosystem Science)
The Earth System is complex, it comprises various physical processes which interact with each other. In our Earth System modelling group we use a regional Earth System model to explore the mechanisms of different physical processes, with a focus on the land-atmosphere interaction that was introduced by changing land surface under future climate changes. Evaluating the interactions of various physical quantities in such complex model is challenging, one reason is these interactions are usually in parallel that are not easy to isolate. Another reason is the strength of the interaction may change under different conditions. An example is the soil moisture (SM) - evapotranspiration (ET) interaction: higher SM can promote ET given a certain temperature and aerodynamic condition, it is labeled as a positive feedback; On the other hand, larger ET dries out the soil more quickly thus lowing the SM giving a negative feedback. These two feedbacks are coupled together composing a balancing loop. The question is how we can use a mathematical approach to quantify the coupling strength in this loop meanwhile considering the temporal (e.g. seasonality) and spatial dimension?