News: Matematiska vetenskaper related to Chalmers University of TechnologyTue, 09 Jun 2020 11:54:20 +0200 aspects of protein lifecycle<p><b>​Valentina Fermanelli contributes to the development and validation of a mathematical framework to study the lifecycle of apolipoproteins. These proteins are regulators of triglyceride levels, which are important risk factors of cardiovascular diseases, the first cause of death in the world today.</b></p><p>​<img class="chalmersPosition-FloatRight" alt="Mathematics applied to solve real-world problems" src="/SiteCollectionImages/Institutioner/MV/Nyheter/DescriptionValentinaFermanelli250x.png" style="margin:5px" />Biomathematics is an interdisciplinary subject strongly increasing with the development of new algorithms that can be used in new computer software. It describes biological processes in mathematical terms to frame and solve otherwise unsolvable research questions in biology and medicine. Apolipoprotein kinetics is one of the processes that are only possible to study thanks to mathematical modelling.</p> <h2>The effects of fructose on lipid metabolism</h2> <p>In her PhD thesis, Valentina has analysed time series data generated from three experiments with a nonlinear mixed effects modelling framework, where the individuals are considered as a sample of a larger population and the statistical model is already embedded in the parameter situation. One of the datasets studied concerns a fructose intervention in abdominally obese individuals. Since many people today drink fructose-containing soda, the effect of such consumptions on lipid metabolism is an important question. By studying how fast the apolipoproteins are formed and released in the blood and how fast they are removed, the knowledge on lipid metabolism is enhanced. One of the results of the thesis, due to the combination of apolipoprotein and lipoprotein kinetic data, uncovers the cause of why hypercaloric fructose leads to increase in triglyceride levels in the blood.</p> <p><img width="170" height="220" class="chalmersPosition-FloatLeft" alt="Valentina Fermanelli" src="/SiteCollectionImages/Institutioner/MV/Profilbilder/valentinafermanelli2.jpg" style="margin:5px" />Valentina has a double master’s degree in applied mathematics from Università degli Studi di Camerino in Italy and Technische Universität Clausthal in Germany. It was in Germany that she really discovered applied mathematics, and came to love the fact that abstract mathematics can solve real-world problems through modelling and simulations.</p> <p>– I started looking for a PhD project, and when I saw the one in Gothenburg I thought “this is made for me!” After I came back from the second interview I asked my mother, who is a primary school teacher and had been to Sweden through work, what the country was like. She told me about children playing in the snow and that both boys and girls learnt wood craft in school, well that was fascinating! </p> <h2>Developing not only as a scientist</h2> <p>There is much that Valentina has liked about her PhD studies, such as the beautiful work environments and the many wonderful people in the department that have made her feel at home. She also mentions the way PhD students are treated where you can call your supervisor by name, be represented in different committees and where the hierarchies overall are low. And she really liked the GTS (General and Transferable Skills) courses that develop the participants not only as scientists but as persons as well. During her PhD studies she has had the opportunity to visit Japan for ten months in total and work with people in similar research fields. She is grateful for her time here in the Mathematical Sciences department that has opened many doors.</p> <p>But it can also be a struggle to be a PhD student, and to cope Valentina has used EFT (Emotional Freedom Techniques) and laughter yoga. She wants to let more people know these techniques, so she will soon after her thesis defence start a course in laughter yoga at a yoga centre here in Gothenburg. Her dream now is to study the effects of these techniques, through mathematical models of course! That the thesis defence has to be online due to corona restrictions has its advantages, now family and friends from all over the world can easily join.<br /><br /><em>Valentina Fermanelli will defend her PhD thesis “Mathematical aspects of apolipoprotein kinetics, with focus on metabolic diseases” on June 15 at 13.15 via Zoom. Supervisor is Martin Adiels, Sahlgrenska Academy.</em><br /><br /><strong>Text</strong>: Setta Aspström<br /><strong>Photo</strong>: private<br /><strong>Picture</strong>: Valentina Fermanelli, Simplified description of how mathematics is applied to solve real-world problems, such as biological and medical ones</p>Tue, 09 Jun 2020 08:55:00 +0200 algorithms for hydrodynamic problems<p><b>​In his PhD thesis, Milo Viviani has combined aspects of geometry and numerical analysis to better understand the 2D ideal hydrodynamics. This is of great relevance in, for example, model predictions of the climate dynamics.</b></p><p><img class="chalmersPosition-FloatRight" alt="Milo Viviani" src="/SiteCollectionImages/Institutioner/MV/Nyheter/miloviviani200x250.jpg" style="margin:5px" />​Fluid dynamics is a large and very active field of research both in pure and applied mathematics. Milo quotes Richard Feynman: “the problem of turbulence [of fluids] is still the most important unsolved problem of classical physics”. The approach presented in his thesis is to use structure-preserving algorithms to solve differential equations that can be applied to hydrodynamic problems. Hydrodynamics is about fluids that are incompressible, as water, but also fluids like the atmosphere. The problem addressed is more specifically about 2D ideal hydrodynamics on a sphere, which is fundamental in modelling oceanic and atmospheric circulation, even for non-terrestrial planets like Jupiter.</p> <h2>New insights into open questions</h2> <p>Of the four papers included, two focus on numerical analysis and two on hydrodynamics. In the first part, Milo develops a new class of numerical schemes for Hamiltonian and non-Hamiltonian isospectral flows. In the latter part, he uses this new tool to better understand hydrodynamics theoretically and efficiently simulate the 2D Euler equations of fluid dynamics on a sphere. This work has given new insights and hints into open questions, as the controversial persistent unsteadiness of the statistical state of a fluid. These findings may suggest that a more complex theory than the current one is needed. This would have a clear impact in model predictions of atmospheric and climate dynamics.</p> <p>Milo has liked mathematics ever since elementary school. He did his master’s thesis in Bergen, Norway, in an Erasmus exchange programme and there he was introduced to and got interested in the research area he has worked with as a PhD student. A visiting colleague of his current supervisor told about the position in Gothenburg, which he applied for and received.</p> <h2>Ups and downs of being a PhD student</h2> <p>– When I started as a PhD student I was curious about the parts of research that involve participating in conferences, travels and meeting people, and I have been well satisfied in this. Sweden does not always have the best weather, but I had been to Norway during the winter and so I knew what to expect. I also got to know some very good friends from whom I have learned a lot of new perspectives and who made me personally grow, and over all I have really had a fun time!</p> <p>That said, research work can often be unsatisfactory. After about two years, Milo began to feel lost in his project and started to lose faith in his own work. Then it turned again, and he is really glad for the last years of his programme: he has got resources and support to continue his work to the best. This process is not uncommon among PhD students and Milo speculates that maybe it is something you must go through. But since the process to some extent is predictable, it could probably be studied and handled.</p> <p>Next, Milo is going to Scuola Normale Superiore in Pisa for a two-years postdoctoral position at the Ennio De Giorgi Mathematical Research Center.<br /><br /><em>Milo Viviani will defend his PhD thesis “<a href="">Symplectic methods for isospectral flows and 2D ideal hydrodynamics</a>” on June 9 at 10.00 via Zoom. Supervisor is Klas Modin.</em><br /><br /><strong>Text</strong>: Setta Aspström<br /><strong>Photo</strong>: private<br /><strong>Picture</strong>: Milo Viviani</p>Wed, 03 Jun 2020 09:00:00 +0200 for exploration of L-functions and modular spaces from KAW mathematics programme<p><b>​The Department of Mathematical Sciences will receive two grants this year from the Knut and Alice Wallenberg’s mathematics programme: Anders Södergren receives funding to recruit an international researcher for a postdoctoral position in Sweden, and Gerard Freixas i Montplet is recruited as a visiting professor.</b></p><p>​<img class="chalmersPosition-FloatRight" alt="Anders Södergren" src="/SiteCollectionImages/Institutioner/MV/Nyheter/anderssodergren-KAW.jpg" style="margin:5px" /><a href="">Anders Södergren</a> is an Associate Professor at the Division of Algebra and Geometry, and the main aim of his research project is to make detailed studies of problems at the intersection of analytic number theory and arithmetic statistics. Of particular interest is the distribution of zeros of L-functions, which are central functions within analytic number theory. The most well-known of all billions of different L-functions is the Riemann zeta function, which holds many secrets regarding how prime numbers are distributed among the natural numbers. The famous Riemann hypothesis states that the distribution of prime numbers is totally random, but nobody has yet managed to prove it. Many mathematicians are convinced that the path to proving the Riemann hypothesis is through families of L-functions.</p> <p><img class="chalmersPosition-FloatLeft" alt="Riemanns zetafunktion" src="/SiteCollectionImages/Institutioner/MV/Nyheter/riemannszetafunktion.jpg" style="margin:5px" />One way to explore the zeros of L-functions was described about twenty years ago by the Katz-Sarnak heuristic. This conjecture combines methods from algebraic geometry with the theory of random matrices, producing accurate predictions of the statistical distribution of zeros in certain families of L-functions. The hope is that this project will lead to precise results that confirm several different aspects of the Katz-Sarnak heuristic. As yet, some of the necessary techniques are still missing, so developing suitable tools is an important part of this project.</p> <p>– The analytic theory of L-functions holds a central position in number theory. The number theory group at the department is rather large, but I am relatively alone in working on such problems. The grant from KAW provides a great opportunity to change that. I hope this will allow me to intensify my work on statistical problems in families of L-functions. Unfortunately, the uncertain situation that the corona virus has put us in makes it impossible to say how difficult it will be to recruit someone for the postdoctoral position.</p> <p><a href="">More detailed description of Anders Södergren’s research at the KAW web &gt;&gt;</a></p> <p><img class="chalmersPosition-FloatLeft" alt="Gerard Freixas i Montplet" src="/SiteCollectionImages/Institutioner/MV/Nyheter/gerardfreixasmontplet-KAW.jpg" style="margin:5px" />Professor Gerard Freixas i Montplet is a researcher at the Department of Mathematics, Jussieu – Paris Rive Gauche, France. He will work with <a href="">Dennis Eriksson</a>, Associate Professor at the Department of Algebra and Geometry, among others. The current project focuses on better understanding both the geometric and the number theoretical properties of moduli spaces. These are at the heart of modern algebraic geometry and were designed about 50 years ago as a way of organising and classifying a large number of geometric objects.</p> <p><img class="chalmersPosition-FloatRight" alt="2-holed torus with significant equations" src="/SiteCollectionImages/Institutioner/MV/Nyheter/torus250x.png" style="margin:5px" />A moduli space can also be regarded as a map. While each point on the familiar geographical maps corresponds to a location, the points in a moduli space correspond to different geometric objects. However, moduli spaces are very complicated maps, so different approaches have been developed to read them. Often, attempts to understand the geometry of the moduli space use properties that are inspired by physics, for example how a kind of temperature varies between different points. From the basis of various energy levels found in the space a special type of function, analytic torsion, is built up, so studies of how this function varies across the moduli space might lead to the desired charting.</p> <p>– It is a great opportunity to be able to work directly with our projects here in Gothenburg for a whole year. We already have an ongoing collaboration that can now be further deepened. In addition, Gerard already has many other links to the research at the department, mainly in algebraic and complex geometry but also in analysis, so that more researchers can benefit from his presence, Dennis Eriksson concludes.</p> <p><a href="">More detailed description of Gerard Freixas i Montplet’s research at the KAW web &gt;&gt;</a></p> <p>The Knut and Alice Wallenberg Foundation started the ten-year mathematics programme in 2014 and has since granted an average of SEK 25 million every year for positions and scholarships. The programme is a partnership with the Royal Swedish Academy of Sciences, which evaluates all nominated candidates. Sixteen prominent mathematicians will receive grants this year.</p> <p><a href="">Read more about all researchers and projects on the KAW web &gt;&gt;</a><br /><br /><strong>Text</strong>: KAW, Anders Södergren, Dennis Eriksson<br /><strong>Photos</strong>: Setta Aspström, Gerard Freixas i Montplet<br /><strong>Equation</strong>: The Riemann zeta function<br /><strong>Illustration</strong>: 2-holed torus with significant equations, Dennis Eriksson</p>Tue, 24 Mar 2020 10:00:00 +0100öran Gustafsson Prize to Chalmers matematician<p><b>​In the borderland between analysis, algebra and geometry: Elizabeth Wulcan, Professor in Mathematics at Chalmers University of Technology, has been awarded the Göran Gustafsson Prize of 2020 by the Royal Swedish Academy of Sciences.</b></p><p><img class="chalmersPosition-FloatRight" alt="Elizabeth Wulcan" src="/SiteCollectionImages/Institutioner/MV/Profilbilder/elizabethwulcan2.jpg" style="margin:5px" />The motivation for the award is <em>&quot;for her central and multifaceted work in the borderland between complex analysis and commutative algebra&quot;.</em></p> <p><a href="/en/Staff/Pages/elizabeth-wulcan.aspx">Elizabeth Wulcan</a> uses tools from one mathematical area, analysis, to study problems in other mathematical areas - geometry and algebra. Among other things, she works on developing the theory for and applications of so-called residue currents. These can be used to represent basic objects in algebra and geometry (such as curves and surfaces).</p> <p>The theory that she and her co-authors have developed has, among other things, led to new results regarding effective polynomial division, which is a classic problem from the early 1900s. It has also been used to find a brand new way of solving the so-called Cauchy-Riemann equation, which plays a fundamental role in complex analysis and geometry.</p> <p><strong>About the Göran Gustafsson Prizes</strong><br />The prizes are awarded annually since 1991 to researchers who are at most 45 years old, in the fields of mathematics, physics, chemistry, molecular biology and medicine. The universities of Sweden nominate candidates, the Royal Swedish Academy of Sciences reviews the proposals and the award winners are then appointed by the Göran Gustafsson Foundation for Research in Natural Sciences and Medicine. Each prize winner receives SEK 5.1 million in research grants, distributed over three years, and a personal prize of SEK 250 000.</p> <p><a href="">See all prize winners of this year (in Swedish) &gt;&gt;</a><br /><br /><strong>Text</strong>: from the Swedish web site of the Royal Swedish Academy of Sceinces <br /><strong>Photo</strong>: Setta Aspström</p>Mon, 02 Mar 2020 10:15:00 +0100 has scaled up AI, autonomous systems and software at Chalmers<p><b>​WASP Chair Sara Mazur and KAW Chair Peter Wallenberg visited Chalmers to gain insight into the activities. The large research program has scaled up the research at several of Chalmers departments.</b></p>​<span style="background-color:initial">During the visit, Sara Mazur and Peter Wallenberg met Chalmers’ WASP researchers and learned about how the programme has developed at the university. They first met three of the research leaders that Chalmers has recruited with funding from WASP.</span><div><br /></div> <div>Professor Ross D. King has been recruited from the University of Manchester. He aims to make science more efficient with the aid of artificial intelligence (AI). At the Department of Biology and Biotechnology, he will continue his work with a &quot;Robot Scientist&quot;. The focus is to understand how cells work - a research area that is so complex that human scientists struggle, and where robotic help is needed.</div> <div><br /></div> <div>Christopher Zach, joining recently from Toshiba's research lab in Cambridge, is now a Research Professor at the Department of Electrical Engineering, and Fredrik Johansson, with a postdoc from the Massachusetts Institute of Technology, is now an Assistant Professor at the Department of Computer Science and Engineering. </div> <div><br /></div> <div>Christopher's research topic is computer vision and image understanding, and Fredrik's research area is machine learning with a focus on medical applications. With mathematical theory and modelling as a scientific basis, the goal is to develop tools to be used as decision support in autonomous systems and health care. Is it possible to design a system with an ability to reason its way to a correct conclusion?</div> <div><br /></div> <div>“Artificial intelligence offers very promising support in radiology, to identify tumours and other abnormalities in tomography or X-ray images. But work remains to be done to make the systems robust to changes in personnel, equipment and patient groups,” says Fredrik Johansson.</div> <div><br /></div> <h2 class="chalmersElement-H2">WASP projects at five departments</h2> <div>The WASP program has scaled up the research in AI, autonomous systems and software at Chalmers. Since the start in 2018, approximately 50 PhD students and postdocs have been recruited and further recruitments are planned. The initiative is particularly noticeable at the Department of Mathematical Sciences, according to Daniel Persson, Assistant Professor and supervisor in the WASP program.</div> <div><br /></div> <div>“Mathematics for AI has increased at the department, not least the collaboration between research groups and with industry. A total of 14 research projects within AI are ongoing at the department today – thanks in large part to the fact that our researchers have been successful in obtaining grants from WASP,” says Daniel Persson.</div> <div><br /></div> <div>Chalmers Vice President for Research and Doctoral Education Anders Palmqvist is very pleased with how WASP has spread across the university departments.</div> <div><br /></div> <div>“We have ongoing WASP projects at five different departments. Chalmers has a strategic ambition to work across departments through its Areas of Advance, and Chalmers' initial work to mobilise for the launch of WASP was handled in collaboration with the Information and Communication Technology Area of Advance,” says Anders Palmqvist.</div> <div><br /></div> <h2 class="chalmersElement-H2">Successful graduate school</h2> <div>In addition to research projects and strategic recruitments, WASP also runs a graduate school for PhD students with a range of joint courses and network meetings. Christian Berger, from the Department of Computer Science and Engineering, was involved in building up the graduate school.</div> <div><br /></div> <div>“The courses and network meetings, both nationally and internationally, offer great value to the PhD students. It was a challenge to develop an educational programme adapted to students from many disciplines, but what we have achieved broadens the students’ expertise and gives them an ability to communicate their research between the disciplines – which is not always easy,” says Christian Berger.</div> <div><br /></div> <div>During their visit to Chalmers, Sara Mazur and Peter Wallenberg also visited Chalmers Biomechatronics and Neurorehabilitation Lab. Director Max Ortiz Catalan demonstrated two types of research projects with assistance from two patients.</div> <div><br /></div> <div><br /></div> <div><br /></div> <div><strong>About WASP</strong></div> <div>The Wallenberg Artificial Intelligence, Autonomous Systems and Software Program (WASP) is a major national initiative for strategically motivated basic research, education and faculty recruitment in artificial intelligence, autonomous systems and software development, funded by the Knut and Alice Wallenberg Foundation together with the partner universities and participating industry. The starting point for WASP is the combined existing world-leading competence in Electrical Engineering, Computer Engineering, and Computer Science at Sweden’s five major ICT universities: Chalmers University of Technology, KTH Royal Institute of Technology, Linköping University, Lund University and Umeå University. Research projects are also conducted at Uppsala University and Örebro University.</div> <div>The aim is to strengthen, expand, and renew the national competence through new strategic recruitments, a challenging research program, a national graduate school, and collaboration with industry.</div> <div><a href=""></a></div> <div><br /></div> <div>At Chalmers, there is an established collaboration between WASP and Chalmers AI Research Centre, CHAIR, to ensure good synergy.</div> <div><a href="/en/centres/chair/Pages/default.aspx"></a></div> Tue, 25 Feb 2020 17:00:00 +0100 in number theory<p><b>​Broadly speaking, Manh Hung Tran works with solutions of algebraic equations. In his PhD thesis, he has studied the equations which define curves of genus one – the natural generalizations of elliptic curves.</b></p><p>​<img class="chalmersPosition-FloatRight" alt="Geometry of elliptic curves" src="/SiteCollectionImages/Institutioner/MV/Nyheter/Geometryofellipticcurves250x250.jpg" style="margin:5px" />Pure mathematics is abstract and hard to feel or “touch” even with classical subject like equations. To get a better intuition of solutions of equations, they can be drawn as geometric objects. Arithmetic and algebraic problems will then be transformed through a “mirror” to the field of geometry. Among many geometric objects, elliptic curves are interesting ones which appear in many areas of mathematics such as number theory, algebraic geometry and complex analysis. Moreover, they have many applications outside of mathematics such as in computer science and cryptography.</p> <h2>The natural generalisations of elliptic curves</h2> <p>Genus one curves are natural general forms of elliptic curves. In his thesis, Hung studies two different but connected important problems regarding equations that define these curves. The first problem concerns the density of points over the rational numbers on genus one curves. The goal is to be able to uniformly estimate the number of points for a large class of curves which does not individually depend on the given equations. This study might be used in cryptography, where it is important to know the structure of solutions of equations in order to create a strong security code. On this subject, Hung held a popular science talk in the Science Festival last year. But he himself works entirely on the theoretical side.</p> <p>The second problem is about the structure of invariants of genus one models. These invariants are algebraic objects which is stable under natural transformations. Hung has tried to get a correct formula for the two generators of these invariants. </p> <h2>A good working environment</h2> <p><img width="250" height="300" class="chalmersPosition-FloatLeft" alt="Manh Hung Tran" src="/SiteCollectionImages/Institutioner/MV/Nyheter/manhhungtran250x300.jpg" style="margin:5px" />Hung has always liked mathematics, he says he has “followed the flow”. Mathematics is not an easy subject. You must bear in mind that it is fine to be stressful or to get stuck sometimes. On the way, you need to learn also what is not so interesting, or far away from your expertise, in order to get further in mathematics. After finishing his master in Italy, Hung applied for several PhD positions. One of the offers he got was from Chalmers. He did not know much about Sweden but decided to give it a chance. He has not regretted this, as he has found Sweden to be a really good mathematical country, though it is maybe not commonly known. There is also a great working environment, with a much better salary and amenities than many other European countries.</p> <p>Now, Hung is looking for a postdoctoral position. He searches all over the world but would really like to stay in Sweden, or at least in one of the Nordic countries. However, in pure mathematics at least, the postdoctors are strongly encouraged to go abroad. This can be difficult when the postdoctor, as Hung, has a family, and he believes that is one reason why many mathematicians rather go to companies than stay in academia. <br /><br /><em>Manh Hung Tran will defend his PhD thesis “The density of rational points and invariants of genus one curves” on January 29 at 13.15 in the room Pascal, Hörsalsvägen 1. Supervisor is Dennis Eriksson.</em><br /><br /><strong>Text and photo</strong>: Setta Aspström<br /><strong>Picture</strong>: Manh Hung Tran. Geometry of elliptic curves</p>Thu, 23 Jan 2020 16:20:00 +0100 positions in mathematics for artificial intelligence: application deadline March 6<p><b>​We are recruiting six doctoral students in mathematics and mathematical statistics for artificial intelligence, for two projects financed by CHAIR and four projects supported by WASP.</b></p><p><a href="/en/about-chalmers/Working-at-Chalmers/Vacancies/Pages/default.aspx?rmpage=job&amp;rmjob=8281&amp;rmlang=UK">Here is the call for application</a></p> <p>The expansion of Artificial Intelligence (AI), in the broad sense, is one of the most exciting developments of the 21st century. This progress opens up many possibilities but also poses grand challenges. The center &quot;<a href="">Wallenberg AI, Autonomous Systems and Software Program</a>&quot; (WASP) has launched a program to develop the mathematical side of this area. The aim is to promote the competence of Sweden as a nation within the area of AI. We are already taking part in this program through four research projects that started last year. We will now open four new projects:</p> <p>1.<a href="">Generalization Bounds for Deep Neural Networks: Insight and Design</a>, supervisor: Rebecka Jörnsten and Giuseppe Durisi.</p> <p>2. <a href="">Deep Learning for the Optimal Filtering Problem</a>, supervisors: Stig Larsson and Adam Andersson.</p> <p>3. <a href="">Mathematics of Shape Learning</a>, supervisor: Klas Modin. </p> <p>4. <a href="">Group Equivariant Convolutional Neural Networks</a>, supervisor: Daniel Persson. </p> <p>We seek four or more PhD students to be nominated for participation in the WASP AI Graduate School.</p> <p>After our nominations, the final selection of the candidates will be done by WASP. The projects are expected to start on August 15, 2020, but the starting date is flexible.</p> <p>As a counterpart to WASP, Chalmers has recently launched the Chalmers AI Research Centre (CHAIR) to significantly increase Chalmers’ expertise and excellence in artificial intelligence. We are able to announce two PhD positions for the research projects:</p> <p>5. <a href="">Deep Learning and Likelihood-Free Bayesian Inference for Intractable Stochastic Models</a>, supervisor: Umberto Picchini.  </p> <p>6. <a href="">Stochastic Continuous-Depth Neural Networks</a>, supervisor: Moritz Schauer.</p>Fri, 17 Jan 2020 16:15:00 +0100 behaviour in space<p><b>​How do objects in space interact when they are exposed to different forces? What do globular clusters look like? What happens to small particles in space over time? Maximilian Thaller’s PhD thesis has space as study object, with elements both from mathematics and physics.</b></p><p>​<img class="chalmersPosition-FloatRight" alt="Maximilian Thaller" src="/SiteCollectionImages/Institutioner/MV/Nyheter/maximilianthaller250x300.jpg" style="margin:5px" />Maximilian’s research lies within the framework of kinetic theory, where he considers certain meta models which consist of ensembles of particles that all look alike. These models play a role in several different fields in physics, such as plasma physics. But the particles can also, as in Maximilian’s work, signify stars, galaxies and galaxy clusters – it is just a matter of different scales. The particles interact with different forces, such as an electromagnetic field in plasma and a gravitational field in a galaxy. Maximilian investigates the interaction in gravitational fields, i.e. what happens with the particles – if they form time-independent clouds, if they collapse into dense objects, or if they disperse.</p> <h2>The Einstein-Vlasov system</h2> <p>There are two common ways to describe gravity. The oldest and simplest is the Newtonian, but often it is not accurate enough. In Maximilian’s work, the particles do not collide but they “feel” the gravitational field created by all the particles collectively. This is described by the Vlasov equation, which is coupled to Einstein’s theory of General Relativity. Gravity is not seen as a force, but as a curvature of the spacetime that the particles live in. The motivation for using this theory instead is that it can describe astronomical objects like galaxies and galaxy clusters very well. In some contexts the difference is not so big, but certain circumstances need new mechanisms, like when the behaviour of the particles is very different from the usual. Examples are very dense particle clouds, or models of the universe as a whole, allowing for the study of its expansion behaviour.</p> <p>The thesis consists of two parts. The first involves steady states, where time independent clouds of particles like globular clusters too small to be called galaxies are studied as regarding what symmetries they have and how dense they can be. The other part is about small data time evolution, what happens if we only have a few particles scattered around? In space, there is no perfect vacuum, there are always some particles and there are stability questions regarding these – do they for example clump together? Maximilian’s thesis show that the particles move away into infinity and that vacuum space time is stable. There are many others working with these questions through testing different meta models, but the Vlasov model is more complex and more reliable than most.</p> <h2>Collaboration led to PhD position</h2> <p>That Maximilian ended up doing his PhD thesis in Gothenburg is something of a coincidence. He has a physicist background from Constance and was working with similar things in Vienna, where he had a collaboration with Håkan Andréasson, his future supervisor. Håkan suggested that Maximilian should apply for a still vacant PhD position which had not been appointed in the usual admission during Spring, and so he did. Since he was not a Mathematician he had to prove himself and also catch up with courses during his PhD time. In Gothenburg the PhD students read rather many courses compared to other places, but that suited Maximilian’s situation well.</p> <p>– I have had good conditions here, for example I have had the possibility of two stays abroad, each for three months. You are very free as a PhD student in Sweden, which is good as you can follow your research interest, but there can also be difficulties in being certain of what is a good research question and what the relevant methods are. If I had been working more closely to my supervisor all the time I would probably also have had fewer other research contacts than today.</p> <p>After the thesis defence, Maximilian plans to try a different work environment through going to Munich and the private industry. Something with simulations or maybe the financial sector are two options, where mathematical methods as wave equations and geometry can be used.<br /><br /><em>Maximilian Thaller will defend his PhD thesis “On the Einstein-Vlasov system with massless or charged particles: stationary and small data solutions” on January 24 at 10.15 in the room Pascal, Hörsalsvägen 1. Supervisor is Håkan Andréasson.</em><br /><br /><strong>Text and photo</strong>: Setta Aspström</p>Thu, 16 Jan 2020 03:45:00 +0100 mathematics of shape is addressed by new Wallenberg Academy Fellow<p><b>​Associate Professor Klas Modin at the Department of Applied Mathematics and Statistics studies distances in shape analysis. The five-year grant from Wallenberg Academy Fellowship will be used to develop new mathematical techniques to analyse complicated shapes, such as that of a protein or an organ.</b></p><p><img class="chalmersPosition-FloatRight" alt="Distance in shape analysis" src="/SiteCollectionImages/Institutioner/MV/Nyheter/formensmatematik325x100.png" width="325" height="103" style="margin:5px" />​In mathematics, a small distance is synonymous with a small difference. Using the mathematics called shape analysis, researchers can study whether the difference between figures A and B below is smaller than the difference between B and C. The mathematically correct answer depends on which concept of distance is used in the analysis and how sensitive it is to noise. In the project “Shape analysis – geometry and computation”, Klas Modin will build upon mathematical methods in which a transformation group deforms an object. The distance between shapes A and B is then defined as the shortest transformation route that takes A to B. In shape analysis, a shape can, for example, be a surface, an image, an electrical field or a particle cloud in physics.</p> <h2>Need to compare non-rigid shapes</h2> <p><img class="chalmersPosition-FloatRight" alt="Shape representation using de Rham currents" src="/SiteCollectionImages/Institutioner/MV/Nyheter/Representation_av_form250x.png" style="margin:5px" />The research area arose in the early 2000s, motivated by medical imaging problems of comparing organs from different patients in magnetic resonance images (MRI). The organs are non-rigid, they are deformed as soon as the body moves and depending on posture, and a way was needed to quantify differences between shapes. By combining theories partly from the Russian mathematician Vladimir Arnold, who in the 1960s made a geometric formulation of the equations of motion in fluid mechanics, and partly from the Swedish statistician Ulf Grenander, who built a statistical theory for shapes, a useful mathematical framework was obtained.</p> <p><img class="chalmersPosition-FloatLeft" alt="Klas Modin" src="/SiteCollectionImages/Institutioner/MV/Nyheter/ModinKlas_fotoMarkusMarcetic250x300_2.jpg" style="margin:5px" />– The research on shape analysis builds bridges between different mathematical areas, it is a sort of interdisciplinary field within mathematics with many applications that I find very interesting. My research is about developing the mathematics of shape analysis, but by extension, the mathematical techniques that are being developed can become useful tools for researchers who study the shape of proteins through cryo-electron microscopy, or for physicians who use MRIs to search for shape deviations in organs caused by tumours. </p> <h2>Found his field in New Zealand</h2> <p>Klas Modin first got in touch with shape analysis when he was a postdoctoral fellow at Massey University, New Zealand. He then received an international postdoctoral position through the Swedish Research Council at the University of Toronto, where he worked with Professor Boris Khesin, a former student of Arnold. This cooperation has continued after the return to Sweden five years ago. The grant he has now received gives a welcome opportunity to recruit PhD students and focus on the research.</p> <p>The programme Wallenberg Academy Fellows is financed by Knut and Alice Wallenberg Foundation and has been established in partnership with the royal academies and 16 Swedish universities. The intention is that Sweden’s most promising young researchers should be able to concentrate on their research for a long period and have good resources. They also have the opportunity to participate in a mentoring program, which helps boost their scientific leadership.<br /><br />Press release from KAW, <a href="">Twenty-nine young researchers become Wallenberg Academy Fellows 2019 &gt;&gt;</a><br />Interview with another new Wallenberg Academy Fellow, <a href="">Elin Esbjörner at Biology and Biological Engineering &gt;&gt;</a><br />Interview with another new Wallenberg Academy Fellow, <a href="">Witlef Wieczorek at Microtechnology and Nanoscience &gt;&gt;</a><br /><br /><strong>Text</strong>: Setta Aspström<br /><strong>Pictures</strong>: Klas Modin. The second is a shape representation using de Rham currents.<br /><strong>Photo</strong>: Markus Marcetic</p>Tue, 03 Dec 2019 10:00:00 +0100 Professor develops new tools for analysing extremes<p><b>​Richard A. Davis, appointed Chalmers Jubilee Professor of 2019, is visiting the Mathematical Sciences Department for three months this autumn.</b></p><p>​Richard is the Howard Levene Professor of Statistics at Columbia University in New York City. He has strong overlapping research interests, especially as it relates to extreme value theory, with Holger Rootzén, Professor at Chalmers. Although they first met over 35 years ago, Richard had read many of Holger’s research papers as a graduate student in San Diego. Holger’s research on extreme values eventually evolved into a book (joint with Leadbetter and Lindgren) in 1983, which became an instant classic in the field. As it turned out, Richard wrote a major review of the book that appeared in the Journal of the American Statistical Association. Unfortunately, due to their busy schedules and other commitments, they have never had the possibility to work on a joint research project. With this extraordinary opportunity, they hope to change this and are planting the seeds of what is hoped to be an extended and fruitful research collaboration.</p> <img class="chalmersPosition-FloatLeft" alt="Richard A. Davis" src="/SiteCollectionImages/Institutioner/MV/Nyheter/richardadavis250x300.jpg" style="margin:5px" /><p>Richard’s main research areas are in time series and extreme value theory. He has been interested in developing tools and methodology, backed by rigorous theory, that are useful in a wide range of applications from environmental sciences to financial and economic data. He has been particularly interested in estimating structural breaks in time series, modelling heavy-tailed time series, and understanding extremal dependence. His planned work with Holger on extremes is oriented towards developing tools – a toolbox if you will, that are useful in a wide range of applications as to just a dedicated application. </p> <h2>Topics in Time Series course</h2> <p>Some of Richard’s time while at Chalmers is devoted to delivering the course “Topics in Time Series: Old to New” for masters and PhD students from Chalmers and the University of Gothenburg. In the course, he relates the early development of time series focused on linear models that still owns the core of the field, to more recent innovations that focus on nonlinear and nonGaussian modelling.</p> <p>Gothenburg is undoubtedly a lot smaller than New York. Compared to the frenetic, but exhilarating, pace of New York, Richard is enjoying the more peaceful and relaxed lifestyle of Gothenburg. He recently finished a six year term as chair of the Statistics Department at Columbia University and with all the administrative chores this brings, he jokingly says he has “run away”. In about a month he will be back, but the Jubilee Professorship has given him a welcome block of uninterrupted time to focus on research and to interact with students in his class.<br /><br /><strong>Text</strong>: Setta Aspström and Richard A. Davis<br /><strong>Photo</strong>: Setta Aspström<br /><strong>Picture</strong>: by a former PhD student to Richard A. Davis.</p>Thu, 14 Nov 2019 11:10:00 +0100 Talent Award to PhD student in mathematics<p><b>​Milo Viviani has been awarded the New Talent Award at the SciCADE conference in Innsbruck on July 23. It is an international prize given every second year to a new talent in the field of numerical analysis.</b></p><p>​<img class="chalmersPosition-FloatRight" alt="Photo Milo Viviani" src="/SiteCollectionImages/Institutioner/MV/Profilbilder/miloviviani.png" style="margin:5px" />The biannual <a href="">SciCADE</a> (International Conference on Scientific Computation and Differential Equations) conference was hosted by the University of Innsbuck on July 22-26. The New Talent Award is given based on a submitted paper and the recipient should be a graduate student or have obtained the PhD degree not more than four years earlier. Normally the prize is given to a postdoctor, but Milo defended his licentiate thesis just over one year ago, and there is yet some time before he is finished with his PhD thesis.</p> <p>The paper that impressed the prize committee is called <a href="">Lie-Poisson methods for isospectral flows</a>, and is written together with Milo's supervisor Klas Modin. It can be <a href="">downloaded via arXiv</a>. As a winner of the best paper, Milo gave a plenary talk at the conference, and got his registration fee and local expenses covered.<br /><br /><strong>Photo</strong>: private</p>Tue, 30 Jul 2019 13:00:00 +0200 in Digital Twins will revolutionise urban development<p><b>​With today’s technology that enables the creation of digital twins, a car or airplane can be modeled, simulated and optimized before it leaves the drafting table.  A progress that is about to become reality even for something as complex as whole cities. Swedish innovation agency Vinnova have recently announced a grand and long-term investment into a Chalmers based competence centre that will lead the development.</b></p>​Cities are the largest and most complex human artifacts, and also the most resource consuming and waste producing.  The share of the world’s population living in cities is increasing every year, which also increases the need for a transformation into sustainable design of our cities. The integration of digital methods can be of great support in this challenge. Like the process of designing an airplane or a car based on mathematical modeling, simulation and optimisation, cities could be designed to become more livable, efficient and resilient as they may be analysed and experienced before they are built. The undertaking from Vinnova makes the basis of a total investment of SEK 100 million to create opportunities to analyze and test the components of urban development in a completely new way.    <br /><br /> – We are extremely happy and proud. Behind our application is very hard and long-term work from a committed team at Chalmers in close collaboration with our partners, says Professsor <a href="/en/staff/Pages/logg.aspx">Anders Logg</a>,  Department of Mathematical Sciences and one of two designated directors of the centre. <br /><div><h3 class="chalmersElement-H3">Copies improves the original</h3></div> <div>Digital twins is a concept that have revolutionized the manufacturing industry and is used daily to construct increasingly refined products. The technology has spread to include the planning and development of our cities but is usually limited to visual representation. Digital Twin Cities will develop the concept of digital twins for cities by modeling and simulating the city as a complex multi-physics system based on real-time data.    </div> <br /> – Digital Twin may be a well-established concept, but what’s unique about our concept compared to those elsewhere, is that we aim to integrate what is underground, treating the city as a four-dimensional complex system in our simulations, says Professor <a href="/en/staff/Pages/minna-karstunen.aspx">Minna Karstunen</a>, Department of Architecture and Civil Engineering and designated director of the centre.    <br /><br />The uniqueness of the concept was something Vinnova noted in their assessment, expressed in their motivation as follows: ”The novel approach in an otherwise well addressed field was deemed impressive by the evaluators, combining open source, smart city developments and public sector linkages, convincing the evaluators of the potential of the application.”   <br /><div><br /></div> <div><h3 class="chalmersElement-H3">Gathers a diversity in competencies</h3></div>  – We now have the possibility to fulfill and scale up our pilot VirtualCity@Chalmers, which will make the cornerstone in the development of our centre. At the same time, we will now be able to take advantage of the strong competence already existing at Chalmers within modeling, simulation and visualization of cities, by combining our competencies in architecture, engineering, mathematics and computer science, with experience and current challenges from our partners, Anders Logg concludes.    <br /><br />A broad consortium of 28 Swedish and international stakeholders with the base in Chalmers will cooperate in Digital Twin Cities. Cutting-edge research will be conducted in eight different research areas, covering all aspects needed to develop the large-scale digital twin technology, and to harvest the opportunities it brings in new approaches to urban planning &amp; design, architecture and digital construction. To facilitate uptake and implementation for Sweden to spearhead the necessary digitalization of the built environment sector, a particular focus will be on knowledge transfer to industry and public actors.    <br /><br /> – It is a fantastic opportunity and very exciting. This platform will truly be able to utilise the potential of the new department with its amplitude of disciplines and areas that will co-work to solve these important issues, says Professor <a href="/sv/personal/Sidor/fredrik-nilsson.aspx">Fredrik Nilsson</a>, Head of Department.    <br /><div><br /></div> <div><h3 class="chalmersElement-H3">Research Areas</h3></div> Digital Twin Cities will involve researchers from many different areas of research as well as industry partners and organisations from the civil sector, and the activities will be divided into following areas:  <br /><ul><li>Digital Twin PlatformUrban Planning and Design</li> <li>Architectural and Structural Design</li> <li>Digital Construction</li> <li>Modelling &amp; Simulation at the District Level</li> <li>Modelling and simulation at the City Level</li> <li>Visualisation &amp; Auralisation</li> <li>Data Management &amp; Integration</li></ul> <div><br />The preparations for the new competence centre have already started and Digital Twin Cities is planned to be operative in January 2020.<br /><br />Link to the <a href="">press release from VInnova</a> (in Swedish)</div> <div><br /></div> <div><img alt="Triple helix diagram featuring partner logos" src="/sv/institutioner/ace/nyheter/PublishingImages/diagram_vinnova_helix_city-02.png" style="height:470px;width:750px;margin:5px" /><br /><br /><br /></div>Mon, 24 Jun 2019 15:00:00 +0200 operators<p><b>​In his doctoral thesis, Medet Nursultanov investigates spectral properties of the linear elliptic operators in the presence of different singularities.</b></p><p>​<img class="chalmersPosition-FloatRight" alt="Medet Nursultanov" src="/SiteCollectionImages/Institutioner/MV/Nyheter/medetnursultanov170x220.jpg" style="margin:5px" />Elliptic operators are differential operators that generalize the Laplace operator. They are typical of potential theory, and appear frequently in electrostatics and continuum mechanics. A singularity is a point at which a given mathematical object is not defined, or fails to be well-behaved in some particular way. The study of elliptic operators has had the attention of researchers for more than a century.</p> <p>The thesis consists of three parts. In the first, the singularities considered are geometric. Heat kernels are constructed on surfaces with corners for different boundary conditions and mixed problems, which lead to results showing that corners are spectral invariants. The second part deals with linear elliptic second-order partial differential operators with bounded real-valued measurable coefficients, and the last part with spectral properties of Sturm-Liouvelle operators with singular potentials.</p> <p>Medet achieved his master’s degree in Moscow in 2013, and then started to look for PhD positions. The first offer he got was from Gothenburg, a city he did not know much about before coming here. He has however found the environment comfortable and the department friendly. Next, he wants to do a postdoc and stay on in academia.</p> <p><em>Medet Nursultanov will defend his PhD thesis “Spectral properties of elliptic operators in singular settings and applications” on June 12 at 13.00 in the room Pascal, Hörsalsvägen 1. Supervisor is Julie Rowlett.</em><br /><br /><strong>Text and photo</strong>: Setta Aspström</p>Wed, 05 Jun 2019 14:45:00 +0200 diffusion measurements in complex systems<p><b>​The aim of Marco Longfils’ PhD project has been to develop new methods for measuring diffusion from experiments performed with a certain microscope, called confocal laser scanning microscope.</b></p><p>​<img class="chalmersPosition-FloatRight" alt="Single particle tracking" src="/SiteCollectionImages/Institutioner/MV/Nyheter/singleparticletracking250x250.jpg" style="margin:5px" />Diffusion is the random movement of molecules from one region to another. It is important in many fields such as materials science and life science, for example when a drug is released in a body, or when proteins in a cell interacts with binding sites. Statistics is needed to quantify the information contained in microscopy images, and a well-known method is single particle tracking. This means that particles are identified and followed in consecutive frames of a video to measure their diffusive mobility. </p> <h2>More precise results with new method</h2> <p>The thesis describes a promising method that has been developed for single particle tracking, where it is possible to analyse mixtures of particles that have different diffusion coefficients. Thus, the estimation of diffusion in complex systems has been improved, so that the results when performing experiments will be more accurate. The codes and programmes for the method are shared, and Marco has also developed <a href="">a graphical user interface which is freely available to download</a>.</p> <p>The project has been interdisciplinary, and Marco has been responsible for the statistics part, while research institutes in Sweden and Belgium have been responsible for the more experimental parts. With that said, Marco feels that he has learnt a lot about microscopy during these five years.</p> <h2><img width="250" height="300" class="chalmersPosition-FloatLeft" alt="Marco Longfils" src="/SiteCollectionImages/Institutioner/MV/Nyheter/marcolongfils250x300.jpg" style="margin:5px" />Study exchange led to PhD position</h2> <p>When Marco was studying at master level in Italy he had the possibility to do an exchange for six months. He wanted to try a Nordic country, and Gothenburg seemed to be the best option. His supervisor during this time was Sergei Zuyev and he encouraged Marco to apply for an announced PhD position. Since Marco wanted to go more into applications, this project with real world data was just what he wanted. </p> <p>– I have really had a good time here and Gothenburg is a nice city, even if the weather is not what I am used to. I have made many friends and my colleagues are open to discuss with, it is a very collaborative work environment. If I would stay on in the academic world, it would be in Sweden.</p> <p>But instead, Marco is heading for Amsterdam where he will begin at a bank in September. He will work with quantitative analyses such as probability predicting and risk modelling. The field of applications where statistical methods can be used is broad!<br /><br /><em>Marco Longfils will defend his PhD thesis “Quantitative methods for diffusion measurements in fluorescence </em><em>microscopy” on May 29 at 10.15 in the room Pascal, Hörsalsvägen 1. Supervisor is Aila Särkkä.</em><br /><br /><strong>Text and photo</strong>: Setta Aspström<br /><strong>Picture</strong>: Visualization of a sequence of ten consecutive frames of a single particle tracking simulation of diffusing particles, Marco Longfils</p>Thu, 23 May 2019 09:25:00 +0200 requested in medicine<p><b>​Staffan Nilsson has been working with medical statistics a long time. Today he is employed half-time at the Department of Mathematical Sciences and half-time at the Sahlgrenska Academy.</b></p><p><img class="chalmersPosition-FloatLeft" alt="Staffan Nilsson" src="/SiteCollectionImages/Institutioner/MV/Nyheter/staffannilsson250x300.jpg" style="margin:5px" />– Being a statistician is, contrary to what many people believe, a very social profession. To be able to do a good job, a good contact with the experts in the field where the statistics are to be applied is needed, which requires social competence and that the prestige can be put aside. </p> <p>Staffan has been involved in countless medical research projects during the years and has co-authored 200 articles. In the projects, he is often co-supervisor of a PhD student from the Sahlgrenska Academy. Right now he is completing a major work on meta-analyses of SSRI antidepressant drugs. The value of these drugs has been strongly questioned from some quarters, and together with Elias Eriksson and Fredrik Hieronymus at the Department of Pharmacology, Staffan has made a thorough review of the medicines’ effectiveness. The conclusion is that they are better than what has been previously thought.</p> <p>A recently started project is about retina disease as a result of premature birth. The eye develops late and premature babies risk becoming blind, the project is about being able to predict as well as possible which children will need treatment. Here, Staffan supervises a statistician, Aldina Pivodic, together with Ann Hellström at the Queen Silvia Children’s Hospital. They use methods for survival statistics developed by Anders Odén, who defended his PhD thesis at the Department of Mathematical Sciences in 1977, and the project also includes a thorough documentation of these methods.</p> <h2>Genetics, new and hot in the 90s</h2> <p>When Staffan at the age of 40 switched from being a computer consultant to a PhD student in mathematical statistics, the idea to work with medical applications one day was already there, his wife and several of his friends are doctors. Yet it was a coincidence that Jan Wahlström, professor of clinical genetics, contacted Mathematical Sciences at that time, and that Staffan’s PhD project came to be about genetics. After that, the collaboration with Sahlgrenska has just continued.</p> <p>– An early highlight was to be involved as an expert in the parliamentary inquiry in genetic integrity that was made at the time, I was there as a counterweight to the insurance companies, and it was very fun and different.</p> <p>During the Wallenberg initiative Swegene between the years 2003 and 2007 Staffan was the director of the division Bioinformatics, and that together with being responsible for the statistics education for the PhD students at Sahlgrenska during many years has been the basis for a large contact network. When the Swegene initiative ended many people wanted to continue the collaboration, which formed the basis of an agreement between the departments for ten years, replaced by today’s 50/50 employment a few years ago.</p> <h2><img class="chalmersPosition-FloatRight" alt="Staffan Nilsson, Martina Olsson Lindvall, Sofia Klasson" src="/SiteCollectionImages/Institutioner/MV/Nyheter/medicinskstatistik350x305.jpg" style="margin:5px" />The need for statisticians is great</h2> <p>– I have enjoyed these years very much, I like to work with people and I am no good at saying no. I have worked with genetics studies of celiac disease, MS, Parkinson’s, Alzheimer’s, stroke, breast cancer, colon cancer, neuroblastoma etc., but also with HIV and other infectious diseases. In recent years, I have also been involved in several projects related to premature childbirth where we sometimes use registry data. It is this variation, from large registry studies to small experimental experiments with cell lines, that is so appealing.</p> <p>Staffan is often asked questions like “do you have any statistician who could work in my project?”. Although there are already many statisticians at Sahlgrenska today, the need is even greater. A new course starts this autumn where statistical students study together with PhD students at Sahlgrenska, all with a project that includes the need for knowledge in statistics. The course is called Logistic regression and survival analysis, but the idea could be applied to several courses according to Staffan.</p> <p>– It is important to get the possibility to try the reality during the education, that the statisticians meet practical problems and future customers. In Gothenburg there are pharmaceutical companies, biotech companies and a large medical faculty, and many of those who will work with statistics in this city will end up in the medical sphere. <br /><br /><strong>Text and portrait photo</strong>: Setta Aspström<br /><strong>Photo</strong>: Ewa-Lotta Kärrstedt. Staffan Nilsson collaborates with Martina Olsson Lindvall and Sofia Klasson in a project about stroke.</p>Thu, 09 May 2019 21:55:00 +0200