Noon seminar
The informal research seminar of the ALGO group. Talks last roughly 25 minutes, with five extra minutes allocated for discussion. Many presentations are focused on recent conference presentations, or practice talks for upcoming conferences. New members are often asked to give an overview of their field of research. Talks given by invited speakers may take up to 45–60 minutes including questions.
To be kept uptodate about noon seminar presentations, please subscribe to the algoseminarl mailing list.
COVID19 note
Some of the talks are currently conducted via Zoom. To avoid abuse, we do not distribute the join links publicly. To make the links appear in the list below, make sure you are signed in. Alternatively, you can find the join link in the announcement email.
This is the schedule for 2024. Schedules are available between 2005 and 2024.
 Presentation
 Master's defense
 Midterm
 Invited talk
 External talk
 Practice talk
 PhD defense
 Cancelled
Upcoming talks
Send an email to thijs to schedule your talk.

Feb 27, 15:00—18:00
(MetaForum 11/12)
: EuroCG and LATIN Practice Talks Session 1.
－ Abstract
This is a session for practicing EuroCG and LATIN presentations.
The talks will be scheduled among two sessions.
Details on schedule are forthcoming.
Thijs Beurskens  An Interleaving Distance for Ordered Merge Trees
Steven van den Broek  Greedy Monochromatic Island Partitions
Arjen Simons  Hausdorff Morphs with Fewer Components
Tom Peters  Optimal InPlace Compaction of Sliding Cubes
Anna Schenfisch  Lower Bounding Minimal Faithful Sets of Verbose Persistence Diagrams
Max van Mulken  Capturing the Shape of a Point Set with a LineSegment
Thijs van der Horst  Faster and Deterministic Subtrajectory Clustering
Leonidas Theocharous  A CliqueBased Separator for Intersection Graphs of Geodesic Disks in R^2
Soeren Terziadis  On Orbital Labeling with Circular Contours
Nathan van Beusekom  Competitive Searching over Terrainsv

Mar 05, 15:00—17:00
(TBA)
: EuroCG and LATIN Practice Talks Session 2.
－ Abstract
This is a session for practicing EuroCG and LATIN presentations.
The talks will be scheduled among two sessions.
Details on location and schedule are forthcoming.
Thijs Beurskens  An Interleaving Distance for Ordered Merge Trees
Steven van den Broek  Greedy Monochromatic Island Partitions
Arjen Simons  Hausdorff Morphs with Fewer Components
Tom Peters  Optimal InPlace Compaction of Sliding Cubes
Anna Schenfisch  Lower Bounding Minimal Faithful Sets of Verbose Persistence Diagrams
Max van Mulken  Capturing the Shape of a Point Set with a LineSegment
Thijs van der Horst  Faster and Deterministic Subtrajectory Clustering
Leonidas Theocharous  A CliqueBased Separator for Intersection Graphs of Geodesic Disks in R^2
Soeren Terziadis  On Orbital Labeling with Circular Contours
Nathan van Beusekom  Competitive Searching over Terrainsv
Past talks

Feb 20, 10:30—11:00
(MetaForum 4.208)
Tobias van Elk: Estimating Contours Using Uncoordinated Mobile Sensors.
－ Abstract
Wireless sensor networks (WSN) have seen increasing adoption for many different applications and problem domains. A WSN consists of a number of sensor nodes, sometimes referred to as motes, which are connected wirelessly to form a network. Each node measures some physical attribute of its environment and communicates it to a base station by transmitting the data via the other sensor nodes on the network.
We are interested in creating an online algorithm that takes the measurements reported by some WSN to generate an animated contour plot. In other words, we are interested in the development of the contour over time. These measurements evolve over time, thus the algorithm must continuously adapt the animation as new values are reported. In this talk, we discuss relevant, existing literature, present our formal problem statement and our proposed solution and a discussion of its performance.

Feb 19, 12:30—13:00
(MetaForum 15)
Denis Shehu: An Analysis of the Effect of Polysemy on the Topology of the Latent Manifoldan.
－ Abstract
A static word embedding is a ????dimensional vector representation of a word, learned by a machine learning model trained on the occurrences of this word in a text corpus. If the word is a polyseme, i.e. its occurrences in the corpus have different meanings, then its static embedding must represent all these meanings. To achieve this, it has been hypothesized that the region around the embedding must be a singularity. Previous work has used topologybased algorithms for singularity identification to a very limited extent to provide evidence for this hypothesis. We apply three such algorithms to the embeddings of a carefully constructed list
of polysemes and monosemes, i.e. words that have a single meaning (the region around them is hypothesized to not be a singularity). We distinguish two types of polysemes, namely: interclass polysemes, which occur in the corpus as nouns and verbs, and intraclass polysemes, which occur as either nouns or verbs. Before applying the algorithms to the embeddings, we identify and fix some of their shortcomings and evaluate their efficacy on synthetic datasets. This evaluation process aids us to better understand the results of applying the algorithms to the embeddings, results which might suggest that interclass and intraclass polysemes are much more different than expected.

Feb 16, 16:00—17:00
(Atlas 0.710 and Teams)
Pantea Haghighatkhah: Exploring the Geometry of Semantic Spaces.

Feb 13, 11:15—12:00
(MetaForum 6.131)
Markus Utke: Towards Characterizing Truthful Mechanisms for Budget Aggregation.
－ Abstract
In the budget aggregation problem we try to unify different preferences on how to distribute a divisible resource over a number of alternatives. We study mechanisms that are truthful, i.e. do not incentivize agents to lie about their preferences. We try to characterize the sets of mechanisms that satisfy truthfulness in combination with additional desirable properties.

Feb 08, 13:30—14:00
(MetaForum 1.130)
Faezeh Motie: Preperation Phase Defense.
－ Abstract
Faezeh Motie  FPT Algorithms for Finding and Enumerating kSecluded Subgraphs

Feb 05, 13:00—13:30
(MetaForum 3.141)
Jeroen Lamme: Preperation Phase Defense.
－ Abstract
Jeroen Lamme  FPT Algorithms for MultiParty Kidney Exchange

Jan 29, 09:30—10:30
(MetaForum 15)
Vincent Janssen and Maik Dijkstra: Preperation Phase Defenses.
－ Abstract
Vincent Janssen  Thermalaware Task Scheduling for 3D MultiProcessors
Maik Dijkstra  Shortest Paths with Uncertain Node Positions

Jan 24, 11:15—12:00
(MetaForum 14)
Soeren Terziadis: Minimum Link Fencing (A Geometric Approach to a Bovine Problem).
－ Abstract
We study a variant of the geometric multicut problem, where we are given a set $P$ of colored and pairwise interiordisjoint polygons in the plane. The objective is to compute a set of simple closed polygon boundaries (fences) that separate the polygons in such a way that any two polygons that are enclosed by the same fence have the same color, and the total number of links of all fences is minimized. We call this the minimum link fencing (MLF) problem and consider the natural case of bounded minimum link fencing (BMLF), where $P$ contains a polygon $Q$ that is unbounded in all directions and can be seen as an outer polygon. We show that BMLF is NPhard in general, however, it is polynomialtime solvable when each fence contains at most two polygons and is composed of a bounded number of segments, as well as when the convex hull of $P$\$Q$ does not intersect $Q$.