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Friday seminar

The Friday seminar takes place on Fridays at 1 p.m. in room APB/3027. It is a forum for students and researchers to present and discuss ideas relevant to research. The seminar is open for all that are interested. The talks will be held in German.

Upcoming talksImport calendar (iCal)

Date Description

Previous talks

2022

Date Description
Sep 8 10.00 am
Max Friedrich: Parsing discontinuous syntactical structures with neural models.

Verteidigung Diplomarbeit.

We present our idea for a new method of parsing discontinuous constituency trees and its current implementation progress. It consists of a new method of representing discontinuous constituency trees as matrices, an algorithm each for conversion from trees to matrices and vice versa and a neural network architecture that can produce those matrix tree represetations in a fully differentiable manner.

May 20 11.00 am
Max Friedrich: Parsing discontinuous syntactical structures with neural models.

Zwischenvortrag Diplomarbeit.

We present our idea for a new method of parsing discontinuous constituency trees and its current implementation progress. It consists of a new method of representing discontinuous constituency trees as matrices, an algorithm each for conversion from trees to matrices and vice versa and a neural network architecture that can produce those matrix tree represetations in a fully differentiable manner.

Der Vortrag findet online via BigBlueButton statt.

Apr 22 01.00 pm
Jonas Knobloch: Implementierung von Paraphrasierung als Übersetzungsproblem.

Kolloquium Forschungsprojekt Grundlagen

2021

Date Description
Dec 17 01.00 pm
Jonas Knobloch: Implementierung von Paraphrasierung als Übersetzungsproblem.

Zwischenvortrag Forschungsprojekt Grundlagen

Feb 26 10.00 am
Celina Pohl: Normal forms of weighted context-free grammars.

Verteidigung Bachelorarbeit

Jan 22 01.00 pm
Franziska von Albedyll: Dijkstra-Algorithmus und dessen Komplexität.

Zweite Prüfungsleistung AuD

2020

Date Description
Nov 20 01.00 pm
Max Friedrich: Parsing von diskontinuierlichen syntaktischen Strukturen mittels neuronaler Modelle.

Analyse eines Forschungsthemas

Jun 12 12.00 pm
Alexander Jenke: Extraktion von nichtdeterministischen Streaming-String-Transducern aus einem bilingualen Korpus.

Abschlussvortrag Praktikum

01.30 pm
Richard Mörbitz & Thomas Ruprecht: Lexicalization of Probabilistic Linear Context-free Rewriting Systems.

Probevortrag

May 26 09.00 am
Alex Ivliev: Parsing of lexicalised linear context-free rewriting systems via supertagging.

Kolloquium Profilprojekt Grundlagenforschung

10.30 am
Max Friedrich: Morphosyntactic tagging with a meta-BiLSTM model over context-sensitive token encodings.

Kolloquium Profilprojekt Grundlagenforschung

12.00 pm
Frederic Dörband: Sequentiality of Group-Weighted Tree Automata.
Apr 24 01.00 pm
Richard Mörbitz und Thomas Ruprecht: Lexikalisierung von Linear context-free rewriting systems.
Feb 14 01.30 pm
Alexander Jenke: Extraktion von nichtdeterministischen Streaming-String-Transducern aus einem bilingualen Korpus.

Zwischenvortrag Praktikum

02.00 pm
Alex Ivliev: Parsing of lexicalised linear context-free rewriting systems via supertagging.

Zwischenvortrag Forschungsprojekt

Jan 24 01.00 pm
Johanness Hayeß: k-best Decoding of Conditional Random Fields in Sequence Analysis.

Bachelorverteidigung

2019

Date Description
Dec 20 01.00 pm
Max Fiedrich: Moprhosyntactic tigging with a meta-BiLSTM model over context-sensitive token encodings.

Zwischenvortrag Forschungsprojekt

Nov 29 01.00 pm
Johannes Hayeß: k-best Decoding of Conditional Random Fields in Sequence Analysis.

Zwischenvortrag Bachelorarbeit

Nov 8 01.00 pm
Tilo Werdin: Evaluation of coarse-to-fine recognition for weighted tree-stack automata.

Forschungsprojekt Grundlagen

Sep 6 09.00 am
Pius Friedrich Meinert: The Problem of Computing the Most Probable Tree of a Probabilistic Tree Automaton.

Kolloquium Masterarbeit

Sep 2 09.00 am
Marcel Legler: Implementierung eines gewichteten Lattice-based Parsers für Multiple Context-free Grammars.

Zwischenvortrag Forschungsprojekt Grundlagen

Jul 19 01.00 pm
Tilo Werdin: Evaluation of coarse-to-fine recognition for weighted tree-stack automata.

Zwischenvortrag Forschungsprojekt Grundlagen

Jul 15 01.00 pm
Kilian Gebhardt: Data-driven Parsing of Natural Languages with Mildly Context-sensitive Grammars.

Statusvortrag zum Promotionsvorhaben

Several languages (and in consequence also syntactic treebanks for these languages) such as Dutch (Lassy), German (NeGra, TiGer), but also English (Penn Treebank) contain so-called discontinuous structures that cannot be adequately modelled by context-free grammars. In consequence, a class of more power grammar formalisms called mildly context-sensitive has been studied. Although the parsing complexity of these grammar formalisms is polymomial, it is usally of higher degree than that of CFG. Hence, also other methods based on graph reductions and oracle-driven transition systems with more favourable complexity have been proposed.

In this talk I give an overview on different methods proposed for discontinuous parsing. Furthermore, I present my own contributions to the area of grammar-based discontinuous parsing. In particular, I recall linear context-free rewriting systems and hybrid grammars and present a method to learn powerful probabilistic extensions of these grammars. I discuss empirical results when applying said models to data from multiple languages.

Jul 5 01.00 pm
Edgar Dorauasch: The smallest grammar problem.
01.30 pm
Lena Jurkschat: Parsing as reduction.
02.00 pm
Klaus-Rudolph Kladny: Weighting finite-state transductions with neural context.
02.30 pm
Alexander van Le: Coarse-to-fine parsing for expressive grammar formalisms.
03.00 pm
Tilo Werdin: An efficient best-trees algorithm for weighted tree automata over the tropical semiring.
May 24 01.00 pm (45min)
Max Friedrich: Parsing of lexicalised linear context-free rewriting systems via supertagging.

Kolloquium zum Großen Beleg

May 17 01.00 pm
Pius Friedrich Meinert: The Problem of Computing the Most Probable Tree of a Probabilistic Tree Automaton.

Zwischenvortrag Masterarbeit

May 10 01.00 pm
Thomas Ruprecht: Implementation of a Chomsky-Schützenberger n-best parser for weighted multiple context-free grammars.
May 3 01.00 pm
Heiko Vogler: Abstract families of weighted tree languages.
Apr 26 01.00 pm
Franz Pöschel: Kompositionseigenschaften von Baumübersetzungssystemen.
01.45 pm
Tilo Werdin: Neuerungen an j-Algo (Bericht über WHK-Tätigkeit).
Apr 12 01.30 pm
Philipp Langen: Advances in discontinuous latent variable parsing.

Bericht über die WHK-Tätigkeit

Apr 5 01.00 pm (25min)
Max Friedrich: Parsing of lexicalised linear context-free rewriting systems via supertagging.
01.30 pm
Hauke Mewes: Cones for weighted tree languages.
Mar 15 01.00 pm
Max Korn: Neuerungen an Vanda-Studio (Demonstration zur SHK-Tätigkeit).
Feb 1 01.00 pm
Richard Mörbitz: Shortest distances in graphs and hypergraphs.
Jan 25 01.00 pm
[notespaper]

Kilian Gebhardt: On the NP-hardness of finding the best tree generated by a probabilistic regular tree grammar.
Jan 11 01.00 pm
Tobias Denkinger: CYK parsing on GPUs (after a paper by Yi, Lai, Petrov, and Keutzer, 2011).

2018

Date Description
Dec 21 01.00 pm
Olaf Gröscho: Conditional Random Fields für Part-of-Speech Tagging.
01.30 pm
Franz Pöschel: Kompositionseigenschaften von Baumübersetzungssystemen.
Dec 7 12.30 pm
Pius Friedrich Meinert: Transitionsbasierte Generierung von Sätzen aus Abstract Meaning Representations.
Nov 30 01.00 pm
[slides]

Thomas Ruprecht: Extraction of Dyck words from finite automata.
Nov 23 01.00 pm
Richard Mörbitz: Dynamic programming is parsing (and vice versa).
Nov 16 01.00 pm
Kilian Gebhardt: On the internals of disco-dop.

I give an overview of the discontinuous parsing framework disco-dop. In particular, I discuss which high-level and low-level optimizations were chosen in order to achieve state-of-the-art LCFRS parsing.

Nov 9 01.00 pm
[slides]

Tobias Denkinger: Some notes on data structures used in search algorithms.

We talk about pushdowns, logarithmic probabilities, and double-ended priority queues (with example code in Rust).

Nov 2 01.00 pm
[slides]

Thomas Ruprecht: Ansätze zum parallelen Suchen und Parsen.
Oct 26 01.00 pm
[slides]

Richard Mörbitz: A comparison of parsing approaches for linear context-free rewriting systems.
Oct 19 01.00 pm
[slides]

Kilian Gebhardt: Constraining of parse charts.
Oct 12 01.00 pm
[script]

Tobias Denkinger: An introduction to Goldstine-automata.
Sep 28 01.00 pm
Johanna Björklund: Tree-to-graph transducers.
Sep 27 10.30 am
Richard Mörbitz: M-monoid parsing problems </br> (Diplomverteidigung).
01.00 pm
Toni Dietze: A Formal View on Training of Weighted Tree Automata by Likelihood-Driven State Splitting and Merging
(Promotionsverteidigung im Ratszimmer APB/1004).

Sep 18 02.00 pm
Marcel Legler: Evaluation of coarse-to-fine recognition for weighted tree-stack automata (Zwischenvortrag).
Sep 4 09.00 am
Toni Dietze: A Formal View on Training of Weighted Tree Automata by Likelihood-Driven State Splitting and Merging (Probevortrag).
Jul 27 10.00 am
Laura Kallmeyer: Formalizing Role and Reference Grammar as a mildly context-sensitive tree-rewriting grammar.

Role and Reference Grammar (RRG) is a theory of the grammar of natural language which has been developed as a descriptive tool for the analysis of typologically distinct languages, and which takes into account the interaction between syntax, semantics, and pragmatics. While RRG already contains a number of formal elements such as syntactic templates and the logical structures, it lacks a thorough formalization, which makes it difficult to study its formal properties or to develop a computational implementation.

In the talk, we present an outline of how a formal framework for RRG could look like. Our approach adopts and extends concepts from Lexicalized Tree Adjoining Grammars (LTAG) for the specification and composition of syntactic templates. We introduce two general operations, sister adjunction and wrapping substitution, for the composition of elementary syntactic trees. The resulting formalism, Tree Wrapping Grammar (TWG), is more powerful than LTAG. However, if the number of wrapping substitutions that can stretch across a node in the derived tree is limited to some constant k, it is possible to construct a weakly equivalent simple context-free tree grammars of rank k, which is in turn weakly equivalent to a well-nested linear context-free rewriting systems (LCFRS) of fan-out k + 1. Hence, with this linguistically plausible restriction, our formalization of RRG leads to a mildly context-sensitive grammar formalism.

We furthermore show how the operator projection of RRG, which reflects the scopal properties of functional operators, can be integrated into a single tree representation by adding appropriate node and edge features. This extends our formalism to a feature-based TWG.

The work presented in this talk is to a large extent joint work with Rainer Osswald.

12.30 pm (45min)
[slides]

Tobias Denkinger: Two characterisation results of multiple context-free grammars and their application to parsing (Statusvortrag).

We present two parsing algorithms for weighted multiple context-free grammars (short: wMCFGs). The first one is based on an automata characterisation of wMCFGs and a coarse-to-fine parsing algorithm for weighted automata with data storage. The second one is based on a Chomsky-Schützenberger characterisation of wMCFGs.

Jul 20 01.00 pm
[slides]

Niklas Wünsche: Implementierung und Evaluierung eines inkrementellen Parsers in Vanda.
02.00 pm
[slides]

Andy Püschel: Learning to prune LCFRS parse charts
(Forschungsprojekt Grundlagen).

Jul 13 01.00 pm
[paper]

Felix Völker: Incremental Discontinuous Phrase Structure Parsing with the GAP Transition
(Proseminar).

02.00 pm
Pius Friedrich Meinert: Training Deterministic Parsers with Non-Deterministic Oracles
(Seminar).

Jul 6 01.00 pm
Tilman Hinnerichs: Minimalisierung gewichteter Baumautomaten.
Jun 29 01.00 pm
Richard Mörbitz: M-monoid parsing problems.
01.30 pm
Felix Völker: Implementierung eines NeGra-Subkommandos für Vanda-Haskell.
Jun 22 01.00 pm
[book]

Antonia Gerdes: Syntax and semantics of popular recurrent neural network architectures.
Jun 15 01.00 pm
Tobias Denkinger: Automata & transducers with weights & data storage (based on a paper by Jonathan Goldstine).

We develop a definition of automata with data storage by stripping down the classic definition. We observe that automata with data storage can be extended to weighted transducers elegantly, using the free semiring.

02.00 pm
Heiko Vogler: Principle abstract families of weighted tree languages.
Jun 8 01.00 pm
[slides]

Niklas Wünsche: Zwischenvortrag: Implementierung und Evaluierung eines inkrementellen Parsers in Vanda.
Jun 1 01.00 pm
[slides]

Thomas Ruprecht: Chomsky-Schützenberger parsing is chart parsing.

We have a close look at the constructions of C-S parsing and find strong similarities to the well-established chart parsing approach.

May 18 01.00 pm
[slides]

Anja Reusch: Chatbots zur Unterstützung des Spracherwerbs.
May 4 01.15 pm
Johannes Osterholzer: New Results on Context-Free Tree Languages
(Promotionsverteidigung im Ratszimmer).

Apr 27 01.00 pm
Tobias Denkinger: Practical problems with Chomsky-Schützenberger parsing for weighted multiple context-free grammars (in English).
Apr 20 01.00 pm
Tobias Denkinger: Underlying Principles and Recurring Ideas of Formal Grammars (nach einem gleichnamigen Paper von Alexander Okhotin).
Apr 13 01.00 pm
Johannes Osterholzer: New Results on Context-Free Tree Languages.
02.00 pm
[slides]

Pius Meinert: Parsing of natural language sentences to syntactic and semantic graph representations.
Mar 21 02.00 pm
[slides]

Thomas Ruprecht: Implementation and evaluation of k-best Chomsky-Schützenberger parsing for weighted multiple context-free grammars.
Mar 13 10.00 am
[slides]

Richard Mörbitz: M-monoid parsing und Reduktbildung.
Mar 2 12.00 pm
Andy Püschel: Learning to prune LCFRS parse charts.
Feb 2 01.00 pm
Anja Reusch: Chatbots zur Unterstützung des Spracherwerbs.
Jan 26 01.00 pm
[slides]

Christian Lewe: A brief view on Rust and rustomata.
Jan 19 01.00 pm
[slides]

Till Köhler und Andy Püschel: Implementierung eines Part-Of-Speech-Taggers in Haskell.
Jan 12 01.00 pm
[slides]

Thomas Ruprecht: Implementation and evaluation of k-best Chomsky-Schützenberger parsing for weighted multiple context-free grammars.
Jan 5 01.00 pm
[slides]

Heiko Vogler: Attribute Grammars.

2017

Date Description
Dec 15 01.00 pm
[slides]

Richard Mörbitz: M-monoid parsing und Reduktbildung.
Dec 8 01.00 pm
[slides]

Thomas Ruprecht: Parsing linear context-free rewriting systems in Vanda.
Dec 1 01.00 pm
Pius Meinert: Parsing of natural language sentences to syntactic and semantic graph representations.
Nov 24 01.00 pm
Kilian Gebhardt: Word2Vec – The skip-gram model.

I give a short introduction to word embeddings and, in particular, to the skip-gram model implemented in word2vec.

Nov 10 01.00 pm
[slides]

Heiko Vogler: Dynamic programming algorithms for transition-based dependency parsing.
Nov 3 01.00 pm
Kilian Gebhardt: The Inside-Outside Algorithm is just Backpropagation.

The inside-outside algorithm computes so-called inside weights and outside weights for a weighted (intersection-)grammar. I illustrate that each outside weight can also be obtained as a certain partial derivative of inside weights. This property can be exploited to obtain an EM algorithm from automatic differentiation present in tools such as dynet or Tensorflow.

Oct 27 01.00 pm
[slides]

Max Korn: Coarse-to-fine recognition for weighted tree-stack automata.

We apply the idea of coarse-to-fine parsing to recognition with weighted automata with storage by introducing the concept, and implementing an algorithm in the framework rustomata.

Oct 20 01.00 pm
[slides]

Thomas Ruprecht: Parsing linear context-free rewriting systems.

We use weighted deduction systems to describe three different types of parsers for weighted linear context-free rewriting systems. Furthermore, we introduce heuristic weights for these parsers to enable an informed best-first search among parsing results. We implemented all described formalisms in Haskell using the Vanda framework and tested the implementation with grammars extracted from a natural language corpus.

Oct 13 01.00 pm
Tobias Denkinger: Chomsky-Schützenberger parsing for weighted multiple context-free languages.

We present an n-best parsing algorithm based on the Chomsky-Schützenberger theorem for weighted multiple context-free languages. The algorithm will be implemented and evaluated in the future.

Contact

Last modified: 2020-08-19 03:18pm