Department of Mathematics and Systems Analysis


Defence of doctoral thesis in the field of systems and operations research, M.Sc. Edoardo Tosoni, 14.9.2021

30. August 2021

This dissertation develops probabilistic methodologies for strengthening the systematization of scenario analysis for the safety assessment of nuclear waste management facilities. From the perspective of the Finnish and European nuclear waste community, it contains novel results as, traditionally, this community has only relied on non-probabilistic what-if scenarios. The dissertation also addresses two classical objections to probabilistic approaches. First, the difficulty of obtaining information about the scenario probabilities is tackled by generating data through computer simulations and expert judgments. The quality of these data inputs is characterized by accommodating ranges of probability values, which makes it possible to produce risk estimates even in the presence of scarce information. Moreover, the quantification of uncertainties concerning the residual risk level helps assess the comprehensiveness of the analysis, which, as a goal, cannot be readily attained by non-probabilitstic approaches. Second, the dissertation proposes risk importance measures for identifying which scenarios involve greater risks than others. Thus, these probabilistic methods provide support for structured risk management decisions instead of merely lumping all the data inputs into a single risk estimate. The methodologies are illustrated with case studies on nuclear waste management by examining the spent-fuel storage plant in Saluggia (Italy) and the near-surface repository of Dessel (Belgium). Still, the methodological results are generic as they can be extended to many other application areas, such as finance, in which systemic dependencies must be accounted for. The dissertation has been carried out mainly in the framework of the Finnish research programs KYT 2018 and KYT 2022 on nuclear waste management.

Opponent is Professor doctor Man-Sung Yim, Korea Advanced Institute of Science and Technology, South Korea

Custos is Professor Ahti Salo, Aalto University School of Science, Department of Mathematics and Systems Analysis

The public defence will be organised via Zoom and on campus. Link to the event

Zoom Quick Guide

The doctoral thesis is publicly displayed 10 days before the defence in the publication archive Aaltodoc of Aalto University.

Electronic thesis

Defence of doctoral thesis in the field of industrial engineering and management, MSc Juha Törmänen, 16.9.2021

30. August 2021

Today's remote and hybrid work focused environment places new pressures on the well-being and success of both organisations and employees. Systems Intelligence, meaning intelligent behaviour in the context of complex systems involving interaction and feedback, can help the well-being and improvement of teams and individuals even in these challenging conditions. Systems Intelligence has been researched in the Aalto University Systems Intelligence Research Group since the early years of the 2000s, led by Raimo P. Hämäläinen and Esa Saarinen.

This dissertation provides new tools for measuring and illustrating Systems Intelligence. The study introduces the eight factors of Systems Intelligence – Systemic Perception, Attunement, Positive Attitude, Spirited Discovery, Reflection, Wise Action, Positive Engagement and Effective Responsiveness – and demonstrates that these factors can be assessed with self, peer, and organizational evaluations. Additionally, the study introduces the PoSITeams simulation tool that helps people explore socio-emotional systems.

The results of the research show that companies and employees who are seen as successful and high performing are also perceived to be strong in the eight factors of Systems Intelligence. Thus, the concepts of Systems Intelligence can help to articulate and highlight success factors that might otherwise remain overlooked in the workplace. The new measurement tools allow assessing and developing these factors at the individual, team, and organisational levels.

These new methods of measuring and modelling Systems Intelligence are especially useful for developing learning organizations and human resources. Organizational learning has often been developed from a top-down leadership viewpoint and by focusing on improving organizational structures. The methods of Systems Intelligence provide a way to conduct development work also from the grassroots level, focusing on the ways and styles people live their daily lives, and by offering concrete improvement suggestions for one's own behaviour.

Opponent: Associate Professor Doctor Hong Bui, University of Bath, United Kingdom

Custos: Professor Esa Saarinen, Aalto University School of Science, Department of Industrial Engineering and Management

Contact information of the doctoral student:

The public defence will be organised via Zoom. Link to the event

Zoom Quick Guide

The dissertation is publicly displayed 10 days before the defence in the publication archive Aaltodoc of Aalto University

Electronic dissertation (can be read about 12 days prior the defence)

Department's summer excusion 2021

19. August 2021
Despite of the stormy wind and some rain, the participants enjoyed the get-together party and the game of Mölkky. See the photos.

Summer 2022 Bridges conference

5. August 2021
In 2022 we are planning to hold an in-person Bridges conference! Join us for invited and contributed talks, hands-on workshops, art galleries and live performance events, and an excursion.

Defence of doctoral thesis in the field of systems and operations research, M.Sc. Juho Andelmin, 23.7.2021

26. July 2021

This dissertation develops new formulations and algorithms for problems in green logistics, centralized resource allocation, and discrete multi-stage stochastic optimization.

Two new algorithms and a formulation are developed for the optimal routing of vehicles whose fuel consumption is monitored to prevent fuel depletion en route. This formulation is especially useful for the routing of electric vehicles. It first computes all refuel paths between each pair of customers with all possible combinations of refueling station visits, then discards those refuel paths that cannot be in the optimal solution, and finally replaces all refueling stations with the remaining refuel paths. This formulation is the first to combine routing and refueling decisions with minimal overhead. An exact algorithm that utilizes a full arsenal of sophisticated optimization techniques is developed, followed by a metaheuristic that computes near-optimal solutions fast and complements the exact algorithm. Both algorithms for serve as building blocks for future problem generalizations. Notably, the average optimality gap of the exact algorithm on 200 - 300 customer instances is about 0.67%.

The centralized resource allocation model computes efficiency scores for a collection (portfolio) of units, such as hospitals or banks, which are controlled by a central decision maker (DM). The model also helps allocate resources to these units so that the efficiency of the portfolio consisting of these units is maximized. Because the units typically have many inputs and outputs, the corresponding optimization problem has multiple objectives. Thus, all non-dominated portfolios satisfying the DM’s preferences are computed and the units’ relative resource ranges over these non-dominated portfolios are visualized. Our results indicate that relying on conventional efficiency scores in guiding resource allocation decisions can cause inefficiencies.

The Decision Programming framework is presented to solve discrete multi-stage decision-making problems arising in stochastic optimization and decision analysis with a novel formulation. It incorporates different types of endogenous uncertainties and risk measures in constraints and/or objective function. The framework offers more flexibility than standard tools in decision analysis, and it has just been adapted to solve a large-scale project portfolio selection problem with uncertain time-dependent returns.

Opponent is Professor M. Grazia Speranza, University of Brescia, Italy

Custos is Professor Ahti Salo, Aalto University School of Science, Department of Mathematics and Systems Analysis

Contact information of the doctoral student: +358403581315,

Aalto Mathematics professor wins Outstanding Teacher of the Year from the Finnish Foundation for Technology Promotion's

4. June 2021

Aalto University Professor Fabricio Oliveira, 35, teaches mathematical optimisation to technology students. The aim of this discipline is to optimise a system by using mathematical modelling. This can be used to solve problems like working out the most economical solution for a company, or what actions will have the best environmental impact.

The themes of the courses taught by Oliveira are some of the more difficult themes in system and operations research. However, students praise his way of relating complex, technical themes closely to everyday life: in the course, students learn modelling and optimisation through real-life examples. His interactive and energetic teaching style also generates enthusiasm for the topic among the students. This year was also the first time that the recipient of the Teacher of the Year award was an international technology expert.

‘The exceptional year was also reflected in the nominations for the Outstanding Teacher award. The students commended Fabricio Oliveira for the wonderful ways in which he has succeeded in organising his teaching at a time of remote studying. For many years, international experts have played a big role among the Foundation's grant recipients. It’s wonderful to see that these international recruitments are also positively reflected in teaching,’ says Johanna Lamminen, Chair of the Board of the Finnish Foundation for Technology Promotion.

According to Oliveira, the past year and the Teacher of the Year award provide an excellent opportunity to reflect on what has been successful in teaching and which aspects could still be developed.

‘I believe that, in the future, we can combine the best elements of distance and contact teaching. I’m not going to stop doing lecture videos that allow students to study at their own pace. However, nothing can beat face-to-face encounters — in the lecture hall, I can immediately see on the students' faces if my explanation was not clear, or is missing something,’ Oliveira says.

After having worked in Finland, Brazil, the United States and Australia, Oliveira has noticed some differences in teaching between countries. In Finland students are used to musing on what they have learned in peace, and take more encouragement to join in discussions. On the other hand, the high level of comprehensive school teaching is evident in the lecture halls. ‘Students are students regardless of the country. However, it has been really great to see how high a knowledge level the students have achieved even before their university studies,’ Oliveira says.

Further information:

Professor Fabricio Oliveira, Aalto University
+358 40 489 0080


Collineation Grounds Exhibition, 26.5 - 26.8.2021

20. May 2021

Event flyer

After successful student exhibitions of the transdisciplinary course Crystal Flowers in Halls of Mirrors: Mathematics meets Art and Architecture in Heureka Science Centre 2017 and Espoo Cultural Centre 2019, Aalto Math&Arts Minor exhibition returns to Otaniemi Campus in spring 2021. During the course, students from diverse disciplines and various stages of their studies have been working together in the realm of mathematics and arts searching interesting structures and concepts to be scrutinized and developed into tangible objects. This work was guided in collaboration with an interdisciplinary team of teachers via lectures, workshops and tutoring sessions.

The theme of the 2021 course highlighted the fundamental role of projective geometry in the development of modern mathematics and interaction with applied fields. Its original growth out of the efforts of architects and painters to present spatial objects on flat surfaces to an exciting branch of mathematics manifests itself in genuine interconnections, that can be developed across metric geometry and further towards other disciplines. From a beautiful and intricate system of consistent propositions about points, lines and planes, a collection of unexpected results follows, stretching our imagination and strengthening the link between mathematics and visual perception. Hand in hand with projective configurations, the exhibition space provides a frame to implement and share ideas and visions about low dimensional geometry and topology, that have been studied in the context of Aalto Math&Arts.

The sheltered courtyard next to the main lobby of the Undergraduate Centre and its dark-red brick, black granite and copper clad façade provides a solid frame for the exhibition. In the spirit of Alvar Aalto, the student works enliven the premises from several perspectives through surrounding windows.

Teachers, Aalto University:

  • Kirsi Peltonen (Responsible Teacher, SCI Mathematics)
  • Taneli Luotoniemi (ARTS Artistic Research)
  • Laura Isoniemi (ARTS Design, Art Education)
  • Günther Filz (ARTS/ENG Architecture)
  • Pauliina Skyttä (Campus Architect, ACRE)
  • Markus Holste (Curator & Exhibition Architect, ARTS)
  • Marco Rodriguez (Curator & Exhibition Architect, ARTS)
  • Luiza Sevele (Curator & Exhibition Architect, ARTS)



  • Reetta Kalajo, Arja Miller

Kirsi Peltonen: It is strange to go to an abandoned house to meet students via Zoom

18. May 2021
Kirsi Peltonen. Photo: Mikko Raskinen.
Photo: Mikko Raskinen.

How did you become the teacher of the Crystal Flowers in Halls of Mirrors course?

The course Crystal Flowers in Halls of Mirrors: Mathematics meets Art and Architecture started from nothing ten years ago. I teach mathematics at Aalto University's Department of Mathematics and Systems Analysis, and I did not know anyone from the arts or architecture side.

There was a lot of luck on the way. There was a demand for cross-disciplinary, new openings at Aalto University. At the time, Martti Raevaara was the Vice President for Education, and Aalto courses were established. There was nothing new about combining mathematics and art as such, but it had not been presented this systematically before. As a result, an entire minor subject based on this course was born.

I would not have been able to create the course alone. It was important to get people from different fields to commit to it.

What have been the highlights of the course?

My constant source of inspiration is that we have created new connections and a common voice between teachers and students in different fields. There has also been cooperation with museums, such as the Finnish Science Centre, Heureka, and Espoo Museum of Modern Art, EMMA. The museums have participated in the implementation of exhibitions in cooperation with the artists.

A special highlight, however, would be to get the exhibition up and running in these exceptional circumstances. The results of the workshops are abundant, so maybe no one can really prevent the exhibition either. It is now being arranged outside in Otaniemi.

How has daily life been during the corona pandemic in a teacher's perspective?

The Crystal Flowers in Halls of Mirrors course is based on interaction. Attempts have been made to build it, but creating genuine interaction and dialogue while working remotely is really challenging, sometimes even painful. It has required constant adjustments, and plans have had to be changed on the go. I am extremely grateful to the students who have steadfastly bared with us.

Teaching has mainly  taken place online. Small workshops, where students have been divided into different rooms, have been organised in the Design Factory, while some students have participated through a video connection. Organising has been challenging.

The course is very laborious and requires attendance, as well as tolerance of uncertainty. It is handicraft! When everyone is sitting around the same table on a course, it is easier to understand what the other person is talking about. Remote communication causes a lot of misunderstandings, and it is difficult for a third person to join the discussion when the other two have already started.

All students have quite different situations and backgrounds. Nevertheless, they are incredibly adaptable and have the ability to consider different sides and deal with the situations open-mindedly. I believe both students and teachers have started to appreciate face-to-face teaching more. The lack of interaction is uncomfortable and leads to a strange melancholy feeling, and this cannot continue.

What has helped you cope in daily life during the times of Covid-19?

In terms of the epidemic, I feel that Finland has a privileged position. If I reflect on my own experience, I have been through more difficult moments in my career. It is all relative.

I am doing fine; I spend a lot of time outdoors with my husband. In the winter, it was really refreshing when there was a lot of snow, and we got access to ski tracks right from our own yard. I am also practising pilates remotely.

If the internet connection is poor, I drive to Otaniemi to give the lecture. It helps maintain the rhythm, but at the same time it is strange to go to an abandoned building and then “meet” students there via Zoom.

In the autumn, I was able to give one face-to-face lecture, and it was really empowering. It is part of a teacher's identity. However, it was strange that when, during the lecture, I wanted to go and guide the students in their work, I could not go near them.

There is nothing new in remote work as such, it is the everyday life of a researcher. But now the difficulties are starting to become clear. In normal conditions, certain things progress effortlessly through interaction and even occasional encounters, just because I am present in Otaniemi. It is often enough to mention something about a matter in passing. But now, even the smallest matters require calling or writing an e-mail. It takes time and feels a bit foolish.

What are your expectations for the future?

Conferences are an important part of the lives of researchers, and remotely I have participated in conferences, where I would not otherwise have gone. For example, there are now many genuinely cross-disciplinary origami conferences. That said, interaction is also a challenge for conferences, as the most important aspects take place outside the presentations.

The cross-disciplinary Bridges Conference, for instance, was supposed to be held at Aalto University in 2020, and it has been postponed twice. We are now planning it for 2022.

I received a grant from the Magnus Ehrnrooth foundation to produce a book that combines mathematics and art. In other words, we will put down in writing the results emerged in the course over ten years.

In 2016, I was at the University of Monterrey in Mexico and held a course with a local architect. In Shanghai, we organised a Crystal Flowers mini-exhibition and workshops for schoolchildren, teachers, and university students just before the corona. We made a great number of contacts, but then suddenly, everything came to a halt. I wish that in the future, I will be able to increase international cooperation and find wonderful new contacts.

Further information:


Eveliina Peltola: Mathematics is beautiful because in it everything falls into place in a natural way

6. May 2021
Eveliina Peltola. Photo: Lassi Savola.
Photo: Lassi Savola

What are you researching and why?

I have started my assistant professorship of mathematics at Aalto, and I am also continuing in my post as professor in Bonn, Germany.

I research theories linked with mathematical physics. Physicists try to create models of the surrounding world and to confirm them through experimentation. Their mathematical foundations contain problems that mathematicians solve. The models also raise plenty of new questions that are interesting from the point of view of mathematics itself. I want to understand the surrounding world as a whole from a mathematical point of view and to ensure that the models describe what we want them to describe. This means that the theories have a strong foundation, and that the logical inferences are solid.

For example, my research includes a model describing small particles of magnetic materials with the help of statistical physics and quantum field theory. I am not yet involved in cooperation with Aalto's quantum physicists, but I hope that we might find topics of mutual interest in our research in the future.

I also study symmetries in the models, which are transformations that retain the relevant features of a system. Symmetry can be intuitive, such as rotation, or a more complicated mathematical structure. Preserving the characteristics can be literal, or it can mean statistical symmetry, in which the average features of a system are retained. In research I often start from things that are better understood through symmetry, and then I move to more difficult wholes, while building a theory. Symmetries are my friends!


How did you become a researcher?

It was partly coincidental. In upper secondary school I had no clear plan for my future and I was interested in everything.  I did not actually care much about mathematics, which seemed mechanical to me. However, being interested in sciences, I ended up at the Department of Mathematics at the University of Helsinki. My major was mathematics and I also studied physics and chemistry. I found that mathematics pleased me the most. I saw beauty in it - something greater than in the other subjects. On the other hand, my relationship with mathematics warmed up slowly, and I studied it for several years.

I feel that mathematics is beautiful because in it, everything gets arranged in a natural way. Ever since my days at university, the beauty of mathematics for me has been linked with symmetries: things started falling into place for me at a course in advanced algebra. Now I can see how this naturalness is also present in other areas of mathematics. My concept of the beauty of mathematics is abstract and intuitive.

Mathematics is a universal language that we need to get into before we can understand it. Although nowadays I make calculations that might look boring, the outcome can nevertheless be tidy, and there can even be sense in complexity. Mathematicians often get an internal intuition that guides things such as what kind of a result can be expected in a complex calculation. If the result is something different, I start to suspect that there may have been an error in the calculations, or in the reasoning.  I can also apply this intuition when checking the reasoning of the students.

Consequently, internal beauty and intuition concretely guide mathematical research, which is abstract in other respects.

Read more here.

“What I’m really looking forward to is hanging out!”

6. May 2021
Afrin Hossain stood by a wall with trees in the background
Afrin Hossain, Photo credit Matti Ahlgren

What do you study and why?

I’m a third-year student, and I have just started my masters in applied mathematics. I picked it because, like most people that come to applied physics and mathematics, they don’t want to choose a specific thing, and they just go for it, and I’m like that too. I didn’t know what to pick and maths and physics were the areas I was good at. I like the little euphoria you get when you’ve been alone in a room with a pen and a paper and you finally get a proof.

How has the last year been?

The last year has been kind of a… well it’s been the worst year of my university life. I’ve been active in my guild, freshman year was great, I loved getting involved in Vappu. I also took part in the wellbeing committee of our guild, where I did lots of events like organizing puzzle nights, pajama parties, and other fun, casual events that I really liked. In my second year, I also met the Aamu squad (Aalto muslim student association), because we’re such a small tight community, like there’s so few of us the friendship we have is with everybody. For me, the first two years of university were amazing, all the events we did were really fun.

It’s been tough, and the first few months of the corona situation I was really cranky the whole time. I live quite far away from Otaniemi so if people have met up in small groups, I can’t really commute to meet in a small group as it would defeat the point of social distancing. I’ve been relying on Zoom; I feel like I’ve definitely used my share of Aalto’s Zoom server to the max! I feel like for me, coping has been helped by going outside and going on walks. The way I help is I try and talk to my friends: I’ve given myself a quota that I have to fulfil every day. I have to talk to 2 people every day who don’t live in my house with me. That’s what’s keeping me going and I hope it’s helping the other people I’m speaking to as well.

Virtual events haven’t been much of a success with either the guild and Aamu, we haven’t had many people attend either. With Aamu lots of visiting students will message and ask “when’s your next event?” and we’re like “well, it’s not up to us!” I’m the sort of person who used to be in the guild room every day, every evening, and I feel that over the last year I’ve become a little detached from my guild.  When everything ends, I will get all my friends together and talk. I’m not even much of a hugger but I feel like I want to hug everyone I know! What I’m really looking forward to is just hanging out.

I feel that the covid has made smaller groups that are more tight-knit, and we have the tendency of messaging each other over absolutely nothing. For example, a friend might message “Hey I saw a bird that looked really funky,” and because no one wants to study we’ll all start messaging about that. The one good thing  that I think has come out of all this is that it’s less embarrassing to be like “I am lonely, I need someone to talk to” there’s a lower threshold for that. I am also a tutor for my guild, so I talk to freshmen somewhat, and I feel in many ways, they’ve had it the worst. And they are telling me that for freshmen they’ve been able to bond with each other over a shared feeling of “Hey, this sucks” having the common trauma of having their first year of university in lockdown has really banded them, so I guess there’s that!

How has social-distanced Ramadan been?

With Ramadan there are two aspects, the social aspect and the spiritual aspect. And this year for sure the social side has gone terrible. At least we are able to schedule our lives and studies around the spiritual side of Ramadan – like prayer – instead of the other way round. So at least this year it feels like there’s a bit more control over my time.

What do you predict for the future? 

 I feel like organisations are trying their best to make this virtual thing work – it’s given people a chance to try new things. But in some ways it feels like the university doesn't understand the problems we face all the time. In the pre-corona times one of the most important events was when the professors could take a few students to a lunch or a coffee and ask how is the course going and get feedback. It feels a bit in covid that our ability to give meaningful feedback on courses has gone away a bit

I am more on the side of I prefer contact teaching more, but I know that especially with Masters courses there are fewer students who can come, they might be working or whatever, so it would be smart to have lectures that can be recorded and put online. But for the exercise sessions, you can’t even do “okay” without studying with someone, you need to work with someone. The best thing to do is work with your friends, because for example if your work requires reading a textbook, someone will have understood the first 3 chapters better, and someone else will understand the next 4, or something, and it’s a much more effective way of learning. I’m really looking forward to returning to this.

Defense of dissertation in the field of systems and operations research, M.Sc. Anton von Schantz, 31.5.2021

6. May 2021

Several crowd disasters have received worldwide media attention. In summer 2010, in Germany, the Duisburg Love Parade festival gathered around 1 million attendees. The event ended in a tragedy when in the narrow tunnel leading to the festival area, 21 people were trampled to death, and hundreds got injured. More recently, in April 2021, in a religious gathering in Israel, over 40 people died due to dangerous crowd pressures. The media often speaks about panicking crowd as a cause to these disasters. But what do we actually mean when we speak about escape panic?

Since the 50s, social psychologists have been unanimous that escape panic results from the rational behavior of crowd members. Dwindling resources make people behave impatiently. When there is a hurry to escape a dangerous situation, people start to push and overtake their way out. In the early 2000s, physicists showed that the crowd movement dynamics could rather realistically be modeled by accounting for the different forces affecting an individual. Nowadays, the research objective is to develop methods that can prevent crowd disasters in different events and buildings, like in train stations and airport terminals.

This dissertation offers several practical tools for the numerical simulation and optimization of socio-dynamical features of crowd congestion. The individuals play an evolutionary congestion game, where they fight for their escape. When time is running out in a tight space, escape panic emerges from the rational behavior of crowd members. Then physical forces take over, and a crowd disaster is ready. We simulate the situation in a virtual world that we implement on a supercomputer. We show that the local behavior of people causes dangerous human arches to form and break down and the crowd to move in bursts. The simulation results are validated with data from evacuation experiments done in our research group.

We also study the minimum time evacuation problem using rescue guides, i.e., how should rescue guides evacuate a crowd from a building in minimum time? New mathematical models and algorithms are developed to solve the problem. Additionally, worst-case scenarios are accounted for with a risk measure. In the future, crowd disasters could be prevented by combining these methods with sensor data to give predictions and optimal recommendations to the rescue personnel.

Opponent is Professor Armin Seyfried, University of Wuppertal, Germany

Custos is Professor Harri Ehtamo, Aalto University School of Science, Department of Mathematics and Systems Analysis

Contact information of the doctoral student:, +358504346501

The public defence will be organised via Zoom. Link to the event

Zoom Quick Guide

The doctoral thesis is publicly displayed 10 days before the defence in the publication archive Aaltodoc of Aalto University.

Electronic thesis

The builders of digital trust

4. May 2021

More than 5.3 exabytes of information are transferred via the internet every day. This is an enormous amount: all of the words ever uttered in human history could fit into the same space.

The first internet message in history was transmitted over the ARPANET network in 1969. The message was meant to go from University of California UCLA to Stanford University, just over 600 kilometres away. But the phone booth-sized computer switched off before it completed the transmission.

The first-ever message was a stump – LO.

Programming student Charley Kline didn’t give up, however, and turned the machine back on. UCLA messaged LOG, Stanford replied IN – and the researchers even confirmed over the telephone that these letters had in fact been delivered.

Today, more than 300 billion e-mails and 60 billion WhatsApp messages are sent around the world each day. The number of internet users is approaching 5 billion and the average time spent online is some 7 hours a day, most of which happens on mobiles.

Our everyday life became digital in just half a century. What or who makes sure that our online lives are secure?

Concealed images and key pairs

One such person is Aalto University Assistant Professor Chris Brzuska. He specialises in cryptography or encryption methods.

The word krypto is of Greek origin and refers to the hidden or the secret. The Greeks of antiquity would tattoo secret information in image form on the shaved scalps of their slaves and send them out. Once the slave arrived at the destination months later, their head would be shaved again, making the message readable.

Modern cryptography is based on maths and computer science.

‘It researches and develops methods that protect systems and their users from adversarial interference. Whenever data is transferred over the internet, it needs to be encrypted to prevent outsiders from hearing or reading it,’ Brzuska says.

The work is done by employing mathematical algorithms and encryption keys that scramble the message into a format, which can be decoded only with the right key.

There are two principal approaches to encryption: the symmetric-key method and the asymmetric or public-key method. In the first approach, the same key is used to encrypt and decrypt messages, requiring both sender and recipient to either know the key or find a way to transfer it via a secure channel.

Often this cannot be done.

This is when the public-key method is used. It is based on a key pair of a public-key and a secret-key such that the secret-key is hard to compute, given only the public-key. The pair’s public key encrypts the message, while the private key decrypts it. The parties only need to convey their public keys to each other to enable encryption.

‘It’s a really cool concept, without which the entire net’s encryption would collapse in an instant. When Whitfield Diffie and Martin Hellman came up with the idea, few people could have thought that it would have a practical application. Back in the 70s, it was inconceivable that someone would want to secret information with complete strangers,’ Chris Brzuska says.

Read the whole article here:

Everyday choices: Kaie Kubjas, why does mathematics feel safe?

28. April 2021
Kaie Kubjas katsoo lähikuvassa sivulle, hänet on kuvattu lasiseinän läpi, jolloin seinälle kirjoitetut matemaattiset kaavat heijastuvat hänen ylleen.

Photo: Veera Konsti

You study the applications of algebra and mathematics in, for example, biology and computer science. How did you end up becoming a mathematician?

During my childhood in Estonia, mathematics teachers played a significant role in my future career. In the sixth grade, my teacher asked me to take part in a maths competition, and I won. I participated in competitions for a total of seven years and they were a big part of my life, so it was natural for me to go on to study mathematics.

As a young person, as well as mathematics, I participated in physics, chemistry, and even horse-riding competitions. I loved competing!

You have been a researcher all around the world. What is the most interesting thing about your current research? 

Problem-solving in general interests me. I wanted to do a PhD to see if I can crack unsolved problems in maths. In research, it is most interesting to be able to combine different fields. For example, I can apply the methods of one field of mathematics to another. At best, I can even find surprising connections and patterns.

In my latest study, we are looking at the 3D organisation of the human genome. Our methods include algebra, geometry and optimisation. The question we’re trying to answer is ‘does the data we already have about the human genome give us enough information to identify its 3D structure.’ We are trying to use optimisation to develop algorithms to determine the structure.

The research project began when I was a researcher at MIT in Boston, and this is one of the first times algebra has been utilised in genome research.

In another ongoing research project, we use applied algebra and geometry in neuroscience. The University of Tartu is one of the project partners and I am already acquainted with two researchers from there. One of them is a friend from my student days. It is easier to start cooperating on applied and uncertain projects when you know the other people in advance.

You apply mathematics extensively. Do you think maths can be trusted?

Logical thinking is important in mathematics and for me personally as well. In general, I trust maths because results are proved using logical reasoning based on axioms, and previous results.

Research articles are peer-reviewed, but some studies with mistakes have also been published. It may be that something goes unnoticed. So, you have to be careful if you use someone else’s results in your own research.

I like conclusions obtained using logical reasoning. Results with proofs feel safer to me than observations from experiments. I see things the same way in my personal life.

You are the Deputy Convenor of the European Women in Mathematics association. The association promotes the networking of female mathematicians. How could we encourage girls and young women to study maths?

We can encourage mathematically gifted young people to participate in various events such as student conferences, courses, and competitions. If they do not have a correct assessment of their own skills, they may not participate in them.

After all, mathematics is interesting and multidisciplinary – I believe that popular science lectures in schools and universities can help to bring out fascinating aspects of mathematics, and science in general. And there are many different areas of application. Even if maths lessons at school didn’t seem interesting, lectures can be. Sometimes a student might not be on the same wavelength as one teacher but they can sync with another.

It is important to set the same high expectations for everyone. In that way, we don’t discriminate and assume that someone is good or bad at mathematics only based on their gender.

Text: Tiina Aulanko-Jokirinne

What trust gives us

18. March 2021

Filosofi Esa Saarinen, kuva: Mikko Raskinen

Like walking on thin ice – that’s what it feels like we lack trust. Progress becomes cautious and fearful. Philosopher Esa Saarinen says that when trust fades, the problems and suspicions that exist between people can grow larger. 

‘Anxiety sneaks in,’ Saarinen explains. ‘You start to wonder, is the ice strong enough to hold you if it’s already cracked in one spot? And you realise how good you had it when trust was strong.’

The Aalto University professor says it’s hard to be at the forefront of innovation if your mind is jammed full of thoughts of what could go wrong; worries gnaw away at creativity and attention is pulled to tangential matters that don’t progress your actual cause.

But just seeing someone else act in a steady manner, in a way that enhances trust, can banish those false concerns, Saarinen believes.

‘What garners my trust is fairness and uncompromising conduct that doesn’t come from a self-centred place. Put in ice hockey terms, I really admire people who don’t go for the impressive slapshot, but rather prefer the minimal, yet enormously effective, wrist shot instead,’ he jokes.

Trust also helps us make leaps forward. The fact is, sometimes people just don’t notice when something entirely new is on its way and this makes support from – and trust in – others so valuable.

‘If others show trust in us or what we’re doing, it’s easier to have faith in something that’s still finding its final shape,’ he says.

Trust is anticipating the future in the present

Developed with Professor Raimo P. Hämäläinen, Saarinen’s systems intelligence theory merges human sensitivity with engineering. The idea is that the structure of a system, for example, an organisation, will steer behaviour. But once an environment changes sharply and gives rise to uncertainty, its structures don’t usually tell how to act — this is when trust takes on a decisive role. Hidden individual resources that structures conceal can, in such situations, be revealed in quite surprising ways.

Read more here.


Defense of dissertation in the field of mathematics, M.Sc. Laura Jakobsson, 25.3.2021

10. March 2021

The thesis studies cellular resolutions and the invariants of resolutions of monomial ideals. The area of the thesis is combinatorial commutative algebra, and as much of pure mathematics, the studied questions in the thesis are motivated mainly by fascination towards these combinatorial mathematical objects and applying new tools to study them.
The questions on resolutions and their invariants have been around for a long time, and over the years they have become a rich topic, with a variety of directions including cellular resolutions. We look at cellular resolutions from a category-theoretic point of view and apply tools from representation stability to study them. Representation stability is a relatively new area of mathematics and uses abstract methods to study stability in families of mathematical objects.

The first part of the thesis focuses on cellular resolutions and categorical representation stability.
Among the main results is the definition of the category of cellular resolutions and establishing the basic properties for it. Furthermore, it is shown that important topological constructions, like the homotopy colimit, lift to this category and that discrete and algebraic Morse maps are morphisms in this category.
The category of cellular resolutions opens up cellular resolutions for applying tools of representations of categories, and the application these tools provides the remaining main results of the thesis. The most important result being that the particular families of cellular resolutions have finite generating sets for their syzygies. 
The second part of the thesis is on the combinatorial formulas for algebraic invariants of ideals coming from specific graphs, known as Booth—Lueker graphs. The invariants in question come from free resolutions and keep in the theme of the topics studied in the other parts of the thesis.

Opponent is Professor Anton Dochtermann, Texas State University, USA

Custos is Professor Alexander Engström, Aalto University School of Science, Department of Mathematics and Systems Analysis

The public defence will be organised via Zoom. Link to the event

Zoom Quick Guide

The dissertation is publicly displayed 10 days before the defence in the publication archive Aaltodoc of Aalto University

Electronic dissertation

Journal awards Emilia Lahti's sisu study as article of the year

22. February 2021

The first research article by Emilia Lahti, a doctoral candidate studying the Finnish construct of sisu was published in 2019. It was also the first systematic study on sisu. Now the International Journal of Wellbeing has recognised the research article as the best article of 2019.

In the article, Lahti analysed data from the responses of more than 1,000 people using thematic analysis. The accolade of “Best Article of 2019” is all the more special, as Lahti was the sole author of the paper.

‘It was a personal project and the task was challenging as a first article. By now I know that I do not always have to choose the hardest path available.’

Lahti's doctoral dissertation is a hybrid type, comprising of one published article, and three essay-type articles. In the other articles of her sisu dissertation, Lahti discusses her run in New Zealand as an experiential inquiry into sisu, while creating a theoretical frame of reference for sisu based on the Systems Intelligence theory created by Professor Esa Saarinen and Professor Raimo P. Hämäläinen.

The in-depth phenomenological study on the 2400-kilometre New Zealand ultra-run utilizes Lahti's own experiences, observations, and reflections.
Journal awards Emilia Lahti's sisu study as article of the year | Aalto University

28th Nordic Congress of Mathematicians

27. November 2019
28th Nordic Congress of Mathematicians, Aalto University, Finland, August 18-21, 2022

Page content by: webmaster-math [at] list [dot] aalto [dot] fi