## Archived seminars in MathematicsSeminars 1 to 50 | Next 50 seminars |

### Prof Mathieu Sellier

*University of Canterbury*

Date: Friday 13 August 2021

Many flows encountered in our daily lives involve a moving boundary. The shape of a raindrop, for example, evolves as it falls through the air. Likewise, the free surface of a river deforms as it encounters obstacles. While the mathematical ingredients required to describe such flows have been known since the late 19th century and are encapsulated in the Navier-Stokes equations, solving complex flows with a moving boundary or interface still poses significant challenges and provides stimulating cross-disciplinary research opportunities. The question at the centre of the research I will present is “if information about the evolution of a moving interface is available, can we indirectly infer unknown properties of the flow?” Such a question falls in the realm of inverse problems for which one knows the effect but is looking for the cause. Specifically, I will talk about how it is possible to estimate the fluid properties of lava just by looking at how it flows or what is the best way to rotate a pan to cook the perfect cr\^{e}pe.

### Brendan McCane

*Otago Computer Science*

Date: Tuesday 1 June 2021

### Robert A. Van Gorder

*University of Otago*

Date: Tuesday 25 May 2021

Students are welcome to attend!

### David Bryant

*University of Otago*

Date: Tuesday 18 May 2021

### Anindya Sen

*Department of Accountancy and Finance*

Date: Tuesday 4 May 2021

The Puzzle: A sadistic prison warden plays the following game with a group of 100 prisoners. They are to be lined up in the morning --- each of them wearing a hat which is either black or white --- in such a way that each prisoner can see the hats of everyone in front of him. Then the warden will from the back, loudly asking each prisoner ``What's the colour of your hat?'' and each prisoner has to shout out ``Black'' or ``White'' so that everyone can hear. If they say anything else they will be instantly executed. If the colour is correct they go free, else they are executed. (Yes, this is a bit morbid.) The prisoners are given one evening to discuss a strategy to save themselves as far as possible. What is the maximum number of prisoners who can be saved with certainty?

Surprisingly enough, the answer is ``All but one''.

### Chris Stevens

*Department of Mathematics and Statistics*

Date: Tuesday 27 April 2021

### Melissa Tacy

*University of Auckland*

Date: Tuesday 13 April 2021

### Lena Collienne

*Computer Science University of Otago*

Date: Tuesday 30 March 2021

### Lorenzo Toniazzi

*University of Otago*

Date: Tuesday 23 March 2021

### Chris Horvat

*Brown University USA*

Date: Tuesday 16 March 2021

### Bruce Weir

*Department of Biostatistics, University of Washington*

Date: Friday 5 February 2021

### Prof Rod Gover

*Department of Mathematics, University of Auckland*

Date: Thursday 3 December 2020

### Colin Fox

*Physics University of Otago*

Date: Tuesday 17 November 2020

### Raphael Krier and Cesar Acevedo Ramirez

*Department of Geolgraphy University of Otago*

Date: Tuesday 20 October 2020

$\cdots$

Spurs and Grooves (SAG) structures can be found on coral reefs around the world. However, there are few studies that relate SAG morphology with wave transformation process. Using an array of pressure sensors and current meters deployed over 10 days we present observations of wave dissipation over SAG structures at Xahualxol, Quintana Roo, Mexico. This site has a different morphology of SAG compared to previous studies. Our results indicate that SAG structures are more important in wave transformation than has previously been reported. The rate of dissipation (up to 80W/m2) and the wave dissipation friction factor, fw, (1.1) found, are also high compared to previous values found on other reefs. We also found that the wave dissipation rate over the spurs can be up to three times higher than in the adjacent grooves. This study demonstrates that SAG morphologies play a discernable role in wave dissipation over the forereef.

### Mike Paulin

*Department of Zoology University of Otago*

Date: Tuesday 13 October 2020

### Dr Hamza Bennani

*Department of Computer Science at Otago*

Date: Tuesday 6 October 2020

We validated the results in vitro on radiographs of dried vertebrae with models constructed from a laser-scanner, then in vivo on radiographs of living patients with models extracted from CT scans or MRI.

The results show the feasibility of generating personalised models of patients from bi-planar radiographs.

The contributions are:

- Evaluation of the methods for creating 3D models of vertebrae and estimation of the errors in comparison with ground truth data. These methods are applicable to other free-form shapes;

- Creation of landmark free ASMs of lumbar vertebrae;

- Definition and evaluation of a process for estimating the shape and position of lumbar spine from uncalibrated bi-planar radiographs.

### Anindya Sen

*Department of Accountancy and Finance University of Otago*

Date: Tuesday 29 September 2020

### Mike Steel

*University of Canterbury*

Date: Tuesday 11 August 2020

### Joshua Ritchie

*Mathematics and Statistics Department University of Otago*

Date: Tuesday 21 July 2020

### David Bryant

*Mathematics and Statistics, University of Otago*

Date: Tuesday 17 March 2020

### Melissa Tacy

*Mathematics and Statistics Department University of Otago*

Date: Tuesday 10 March 2020

### Ronald Peeters

*Economics Department University of Otago*

Date: Tuesday 3 March 2020

### Sebastian Herr

*Bielefeld University*

Date: Tuesday 11 February 2020

### Christian Lubich

*Mathematisches Institut Universitaet Tuebingen*

Date: Tuesday 12 November 2019

### Yiming Ma

*Mathematics and Statistics, University of Otago*

Date: Tuesday 8 October 2019

### Phillip Wilcox

*Mathematics and Statistics, University of Otago*

Date: Thursday 3 October 2019

### Tom McCone

*Department of Mathematics and Statistics*

Date: Tuesday 1 October 2019

### Paul Gardner

*Department of Biochemistry, Otago*

Date: Tuesday 24 September 2019

### Travis Scrimshaw

*University of Queensland*

Date: Tuesday 17 September 2019

### Radek Erban

*University of Oxford*

Date: Tuesday 10 September 2019

### Ronald Peeters

*Economics Department*

Date: Tuesday 3 September 2019

### Jinge Lu

*Otago Computer Science*

Date: Tuesday 20 August 2019

### Fabien Montiel

*Department of Mathematics and Statistics*

Date: Tuesday 13 August 2019

### Dmitry Jakobson

*McGill University*

Date: Tuesday 6 August 2019

### Steven Mills

*Department of Computer Science*

Date: Tuesday 30 July 2019

### Zach Weber

*Philosophy Department University of Otago*

Date: Tuesday 23 July 2019

### Arkadii Slinko

*Department of Mathematics. University of Auckland*

Date: Tuesday 9 July 2019

### Leo Tzou

*University of Sydney*

Date: Tuesday 11 June 2019

### Florian Beyer

*Mathematics and Statistics, University of Otago*

Date: Tuesday 28 May 2019

### Brendan Creutz

*School of Mathematics and Statistics, University of Canterbury*

Date: Tuesday 14 May 2019

### Michael Albert

*University of Otago Computer Science*

Date: Tuesday 7 May 2019

### Geertrui van de Voorde

*School of Mathematics and Statistics University of Canterbury*

Date: Tuesday 16 April 2019

### Sarah Wakes

*Department of Mathematics and Statistics*

Date: Tuesday 9 April 2019

### Tim Candy

*Department of Mathematics and Statistics*

Date: Tuesday 2 April 2019

### Conor Finnegan

*University College Dublin*

Date: Tuesday 26 March 2019

### Andrew Robinson

*University of Melbourne*

Date: Thursday 21 March 2019

### Lech Szymanski

*Department of Computer Science, University of Otago*

Date: Tuesday 19 March 2019

### Robert van Gorder

*Department of Mathematics and Statistics, University of Otago*

Date: Tuesday 12 March 2019

These conditions generalize a variety of results known in the literature, such as the algebraic inequalities commonly used as sufficient criteria for the Turing instability on static domains, and approximate or asymptotic results valid for specific types of growth, or for specific domains.

### Russell Higgs

*School of Mathematics and Statistics, University College Dublin*

Date: Tuesday 5 March 2019

### Alex Gavryushkin

*Department of Computer Science University of Otago*

Date: Tuesday 16 October 2018