Department of Mathematics and Systems Analysis

# Lectures, seminars and dissertations

* Dates within the next 7 days are marked by a star.

Miika Hannula (University of Helsinki)
On database dependencies and information inequalities
* Monday 03 April 2023,   15:15,   M2 (M233)
In databases, notions of dependence and independence play a crucial role. For instance, every database relation typically has a key, which is a set of attributes that functionally determines the remaining attributes in the relation. By taking a uniform distribution over the database relation, these dependency notions can be recast using Shannons information measures. Consequently, logical implication between database dependencies can (sometimes) be reconceptualized as an information inequality, that is, a linear inequality over entropies. In this talk we review these connections and also consider information inequalities from a computational perspective. Unlike logical implication in database theory, not much seems to be known about the exact computational complexity of decision problems associated with information inequalities.
Algebra and discrete mathematics seminar

Ivàn Blanco Chacón
Twin primes in quadratic sequences and a partial answer to a conjecture by Sun
* Wednesday 05 April 2023,   15:15,   M3 (M234)
The following conjecture was made in the 2016 Ireland BT Young Scientist Competition: every prime number q>3 can be expressed as q=p+n(n+1), with p a twin prime and n>0. This conjecture was satisfactorily tested for the first 100 millions of primes, and puzzled by such phenomenon, Gary McGuire asked me to think about a possible proof (or disproof) of the conjecture. The first result I came across is the proof that the validity of the conjecture would easily yield the existence of infinitely many twin primes. The conjecture remains open, but we proved that for each prime q of a set of primes of density 1, can be written as q=p+n(n+1), with p < q also prime (not necessarily twin), which is a weak version of a conjecture by Sun. In the present talk we give a sketch of this proof.
ANTA Seminar / Hollanti et al.

Peter Kristel (Bonn)
TBA
Tuesday 11 April 2023,   10:15,   M3 (M234)
Aalto mathematical physics seminar (Kytölä, Peltola, Sahlsten)

Kash Barker, Ph.D., (University of Oklahoma, USA)
Two-Stage Stochastic Program for Environmental Refugee Displacement Planning
Tuesday 11 April 2023,   15:15,   M1 (M232)
Forced displacement is a global problem that requires planning for the relocation and integration of displaced people. Most studies focus on conflict-driven forced displacement, and hence the refugee resettlement problem. These studies generally focus on short-term planning and assume that demand within the fixed time interval is given. However, forced displacement, including environmental displacement as well as conflict-driven displacement, is not a one-time event. On the contrary, it is an ongoing and long-term process with dynamic parameters. We are interested in the long-term displacement problem, especially for climate-driven cases in which people will be forced to leave uninhabitable regions in to escape slow-onset climate change impacts such as water stress, crop failure, and sea level rise. To reflect the long-term planning requirements of the climate-driven displacement problem in the parameters and the model, we propose a two-stage stochastic program where demand uncertainty is represented with various demand scenarios, demand and capacity are managed dynamically, and integration outcomes and related costs are optimized.

Systeemitieteiden kandidaattiseminaari / Bachelor seminar in systems analysis
Monday 17 April 2023,   09:30,   Riihi (Y225a)
Further information

Konstantin Izyurov (University of Helsinki)
TBA
Tuesday 18 April 2023,   10:15,   M3 (M234)
Aalto mathematical physics seminar (Kytölä, Peltola, Sahlsten)

Serge Kas Hanna
Error-correcting codes for DNA storage
Wednesday 19 April 2023,   16:15,   M3 (M234)
DNA storage is a promising candidate for next-generation storage systems due to its compactness, high durability, and energy efficiency. However, the process of storing digital data in synthetic DNA suffers from deletion and insertion errors that may affect the sequence of nucleotides during synthesis, sequencing, and storage. The reliability of the DNA storage can be improved by integrating codes that correct deletions and insertions within the storage system. This talk will give a general overview of deletion/insertion correcting codes and discuss the specific encoding and decoding constraints imposed by the technologies used in DNA storage systems.
ANTA Seminar / Hollanti et al.

Pattanun Chanpiwat (University of Maryland & Aalto University)
The policy graph decomposition of multistage stochastic programming problems
Thursday 20 April 2023,   16:15,   M203
Further information
We start at 16.00h with coffee & pulla. The talk starts at 16.15h.
Gamma-optinars - Seminars of the Group of Applied Mathematical Modelling and Optimisation (GAMMA-OPT))

Prof. Giacomo Micheli (U. South Florida)
TBA
Friday 05 May 2023,   11:15,   M3 (M234)
ANTA Seminar / Hollanti et al.

Systeemitieteiden kandidaattiseminaari / Bachelor seminar in systems analysis
Tuesday 16 May 2023,   09:30,   Riihi (Y225a)
Further information

Matteo Allaix
TBA
Wednesday 24 May 2023,   16:15,   M3 (M234)
ANTA Seminar / Hollanti et al.

Prof. Marcus Greferath (University College Dublin)
TBA
Wednesday 31 May 2023,   16:15,   M3 (M234)
ANTA Seminar / Hollanti et al.

Systeemitieteiden kandidaattiseminaari / Bachelor seminar in systems analysis
Friday 16 June 2023,   09:30,   Riihi (Y225a)
Further information

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