## New hourly paid teachers of mathematics and systems analysis for spring 2025

9. October 2024

The Department of Mathematics and Systems Analysis is seeking

**New hourly-paid teachers in Mathematics and Systems Analysis for spring term 2025.**

Your tasks include teaching in exercise groups and grading exercises and exams.

Regarding teaching in mathematics, we expect the applicants to have completed at least 20 credits of mathematical studies at university level with good grades. Regarding teaching in systems analysis (courses MS-C/E2xxx), we expect the applicants to have completed the course they would like to teach. If you have previous experience in teaching, it is considered as an advantage, but is not necessary. This is a part-time job (2-4 hours/week). The salary is 30-40 euros/teaching hour based on your education level.

Grading exercises and exams will be (typically) compensated separately (300-400 euros depending on your education and the course level).

**Read carefully!** If you are *not working for Aalto* at the moment you apply, fill in the application form here. If you *are working for Aalto* at the moment you apply, you have to apply as an internal candidate via Workday, see instructions Sisäisen työpaikan hakeminen | Aalto-yliopisto.

Attach an open motivation letter, a cv and a transcript of records as one PDF file.

Deadline for the applications is **Monday 4 November 2025**.

Based on the applications, we will invite some of the applicants for a web interview.

More information: johanna.glader@aalto.fi

Note: if you have previously worked as an hourly-based teacher at the MS Department, you have received a separate link from johanna.glader(at)aalto.fi.

## Public defence in Mathematics, M.Sc. (Tech) Pihla Karanko Sept. 19, 2024

9. September 2024

**Doctoral student:** Pihla Karanko

**Opponent:** Assistant Professor Pavel Hubáček, Czech Academy of Sciences, Czech Republic

**Custos:** Associate Professor Chris Brzuska, Aalto University School of Science, Department of Mathematics and Systems Analysis

Cryptography uses mathematical models to simulate real-world scenarios involving secrecy. Since we cannot know what an adversary might do (e.g. use supercomputers to break encryption), researchers try to model worst-case scenarios. Security is defined through "games" where a powerful unspecified adversarial algorithm attempts to break the system under controlled conditions. For example, in studying pseudorandom functions (PRFs), the adversary tries to distinguish between true PRF outputs and random bitstrings. If the adversary cannot guess correctly more than 50 % of the time, the PRF in question is considered secure.

Currently, no algorithm is proven to satisfy the rigorous security definitions for PRFs or other cryptographic tools. Instead, real-life systems rely on plausible candidates that have withstood extensive scrutiny. This reliance on unproven assumptions motivates efforts to reduce and better understand them. E.g. a PRF can be built from a one-way function (OWF), a tool with a simpler security definition.

Main Results:

- The thesis studies ways to get a OWF from a weaker (i.e. easier to break) OWF. We show that the existing methods are likely optimal in efficiency, highlighting the importance of the input distribution in such security amplification techniques. - We transform a weak PRF into a strong one using a special technique. This approach has practical applications in secure password handling, allowing more efficient authentication, where the user does not need to reveal the password to the server it is authenticating to.

- We propose a modification to a popular public key encryption mechanism, Fujisaki-Okamoto (FO) Transform, used in post-quantum secure encryption schemes. Our modification provides a more robust security proof.

- We propose a new security definition for garbling which is a method that allows outsourcing computations to untrusted servers without revealing the function or data. Our definition ensures strong security and efficient input encoding, overcoming current limitations when garbling cryptographic functions, useful for maintaining security when multiple servers encrypt a message jointly and one server becomes corrupted.

Key words: theoretical cryptography, one-way function, pseudorandom function

Thesis available for public display 10 days prior to the defence at: https://aaltodoc.aalto.fi/doc_public/eonly/riiputus/

Contact information:

Email pihla.karanko@aalto.fi

Doctoral theses at the School of Science: https://aaltodoc.aalto.fi/handle/123456789/52

## Armaan Hooda spent one day as a math professor in Aalto

30. August 2024

Here you can read the whole article with Armaan's interview on Aalto's website.

## Public defence in Systems and Operations Research, M.Sc. (Tech) Olli Herrala Sept. 6, 2024

22. August 2024

Mathematical optimization models for supporting climate decision making.

Doctoral student: Olli Herrala

Opponent: Associate Professor Giovanni Pantuso, University of Copenhagen, Denmark

Custos: Professor Fabricio Oliveira, Aalto University School of Science, Department of Mathematics and Systems Analysis

During the past 10 years, we have seen stronger and more frequent impacts of climate change. It is increasingly evident that action should be taken to at least slow down this change. However, making decisions about what exactly should be done is challenging, largely because of the substantial uncertainty in many parts of the problem.

Decision-making under uncertainty has been researched widely in the past 70 years, but most of the research assumes the uncertainty to be independent of our decisions. This is however not the case when making decisions in researching new climate change mitigation techniques such as carbon capture and storage, as these decisions have an impact on the highly uncertain future costs of climate change mitigation. To address this research gap, this thesis presents results on solving problems with decision-dependency in both probabilities and information structures.

This thesis also considers a hierarchical decision-making setting where an international policymaker wants to reduce emissions from electricity production by setting a carbon tax, while avoiding significant decreases in the total production that would increase electricity prices. However, the problem also includes transmission system operators and electricity producers, each with their own goals. The interactions between these players result in a complex problem where a carbon tax might have unexpected consequences such as shifting production from one country to another or simply increasing the price of electricity.

The methods presented in this dissertation allow decision-makers to model and anticipate the effects of decision-dependent uncertainty and hierarchical decision-making processes. The solution methods are based on mixed-integer optimization, leveraging the substantial developments in solving such models during the past 20 years. The case studies presented in the dissertation illustrate the capabilities of the proposed methods and show how they could be used to support decision-making in these complex systems.

Key words: mixed-integer optimization, climate change mitigation

hesis available for public display 10 days prior to the defence at: https://aaltodoc.aalto.fi/doc_public/eonly/riiputus/

## Public defence in Mathematics, M.Sc. (Tech) Kim Myyryläinen June 6, 2024

28. May 2024

Functions of bounded mean oscillation (BMO) and Muckenhoupt weights are essential concepts in modern harmonic analysis. They are used to measure the oscillation of a function at respective scales and to distribute mass to the underlying space. The theory of BMO and Muckenhoupt weights is comprehensive and has many applications also in other fields of mathematics such as partial differential equations.

This thesis studies parabolic bounded mean oscillation and Muckenhoupt weights that are generalizations of the classical time-independent concepts. The objective of the study is to extend the classical theory of BMO and Muckenhoupt weights to the time-dependent parabolic setting. Parabolic BMO and Muckenhoupt weights arise from parabolic partial differential equations, in particular, a doubly nonlinear equation that models nonlinear diffusion. The doubly nonlinear equation is a generalization of the classical heat equation modelling heat conduction.

The results obtained in the thesis include various decay estimates for the oscillation of a function. We show weighted norm inequalities for a parabolic maximal function and obtain a complete theory for the limiting parabolic Muckenhoupt class including characterization and factorization results. The theory for the other endpoint class is also developed and several new characterizations and self-improving phenomena are discovered. The proofs of our results apply covering, chaining and decomposition techniques adapted to the parabolic geometry. In addition to the parabolic framework, other forms of oscillation are considered in the general context of metric measure spaces.

Thesis available for public display 10 days prior to the defence at: https://aaltodoc.aalto.fi/doc_public/eonly/riiputus/

Contact information: kim.myyrylainen@aalto.fi

## Camilla Hollanti elected as a member of Finnish Academy of Science and Letters

26. April 2024

The Finnish Academy of Science and Letters invites academics and scientists who have distinguished themselves in their own fields to become members. Membership of the Finnish Academy of Science and Letters, in common with membership of any other academy of science, is looked on as a considerable achievement in a person’s academic career.

One of the new members is professor of mathematics Camilla Hollanti. Hollanti leads a prominent research group on applications of algebra and number theory. The central topic of her research is to apply the methods of algebra and number theory to problems encountered in communication systems. Applications include wireless security and secure distributed computation.

The academy was founded in 1908 with the aims of promoting scientific research and acting as a bond between those engaged in advanced research.

It arranges meetings, discussions and educational events, in addition to producing scientific publications and issuing comments on topical issues pertaining research and researchers. The Academy of Science and Letters also distributes grants chiefly to young researchers.

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