Suchergebnis: Katalogdaten im Frühjahrssemester 2020

Informatik Master Information
Vertiefungsfächer
Vertiefung in Theoretical Computer Science
Wahlfächer der Vertiefung in Theoretical Computer Science
NummerTitelTypECTSUmfangDozierende
252-0408-00LCryptographic Protocols Information W6 KP2V + 2U + 1AM. Hirt, U. Maurer
KurzbeschreibungThe course presents a selection of hot research topics in cryptography. The choice of topics varies and may include provable security, interactive proofs, zero-knowledge protocols, secret sharing, secure multi-party computation, e-voting, etc.
LernzielIndroduction to a very active research area with many gems and paradoxical
results. Spark interest in fundamental problems.
InhaltThe course presents a selection of hot research topics in cryptography. The choice of topics varies and may include provable security, interactive proofs, zero-knowledge protocols, secret sharing, secure multi-party computation, e-voting, etc.
Skriptthe lecture notes are in German, but they are not required as the entire
course material is documented also in other course material (in english).
Voraussetzungen / BesonderesA basic understanding of fundamental cryptographic concepts
(as taught for example in the course Information Security or
in the course Cryptography Foundations) is useful, but not required.
252-1424-00LModels of ComputationW6 KP2V + 2U + 1AM. Cook
KurzbeschreibungThis course surveys many different models of computation: Turing Machines, Cellular Automata, Finite State Machines, Graph Automata, Circuits, Tilings, Lambda Calculus, Fractran, Chemical Reaction Networks, Hopfield Networks, String Rewriting Systems, Tag Systems, Diophantine Equations, Register Machines, Primitive Recursive Functions, and more.
LernzielThe goal of this course is to become acquainted with a wide variety of models of computation, to understand how models help us to understand the modeled systems, and to be able to develop and analyze models appropriate for new systems.
InhaltThis course surveys many different models of computation: Turing Machines, Cellular Automata, Finite State Machines, Graph Automata, Circuits, Tilings, Lambda Calculus, Fractran, Chemical Reaction Networks, Hopfield Networks, String Rewriting Systems, Tag Systems, Diophantine Equations, Register Machines, Primitive Recursive Functions, and more.
263-4400-00LAdvanced Graph Algorithms and Optimization Information Belegung eingeschränkt - Details anzeigen
Number of participants limited to 30.
W5 KP3G + 1AR. Kyng
KurzbeschreibungThis course will cover a number of advanced topics in optimization and graph algorithms.
LernzielThe course will take students on a deep dive into modern approaches to
graph algorithms using convex optimization techniques.

By studying convex optimization through the lens of graph algorithms,
students should develop a deeper understanding of fundamental
phenomena in optimization.

The course will cover some traditional discrete approaches to various graph
problems, especially flow problems, and then contrast these approaches
with modern, asymptotically faster methods based on combining convex
optimization with spectral and combinatorial graph theory.
InhaltStudents should leave the course understanding key
concepts in optimization such as first and second-order optimization,
convex duality, multiplicative weights and dual-based methods,
acceleration, preconditioning, and non-Euclidean optimization.

Students will also be familiarized with central techniques in the
development of graph algorithms in the past 15 years, including graph
decomposition techniques, sparsification, oblivious routing, and
spectral and combinatorial preconditioning.
Voraussetzungen / BesonderesThis course is targeted toward masters and doctoral students with an
interest in theoretical computer science.

Students should be comfortable with design and analysis of algorithms, probability, and linear algebra.

Having passed the course Algorithms, Probability, and Computing (APC) is highly recommended, but not formally required. If you are not
sure whether you're ready for this class or not, please consult the
instructor.
263-4507-00LAdvances in Distributed Graph Algorithms
Findet dieses Semester nicht statt.
W6 KP3V + 1U + 1AM. Ghaffari
KurzbeschreibungHow can a network of computers solve the graph problems needed for running that network?
LernzielThis course will familiarize the students with the algorithmic tools and techniques in local distributed graph algorithms, and overview the recent highlights in the field. This will also prepare the students for independent research at the frontier of this area.

This is a special‐topics course in algorithm design. It should be accessible to any student with sufficient theoretical/algorithmic background. In particular, it assumes no familiarity with distributed computing. We only expect that the students are comfortable with the basics of algorithm design and analysis, as well as probability theory. It is possible to take this course simultaneously with the course “Principles of Distributed Computing”. If you are not sure whether you are ready for this class or not, please consult the instructor.
InhaltHow can a network of computers solve the graph problems needed for running that network?

Answering this and similar questions is the underlying motivation of the area of Distributed Graph Algorithms. The area focuses on the foundational algorithmic aspects in these questions and provides methods for various distributed systems --- e.g., the Internet, a wireless network, a multi-processor computer, etc --- to solve computational problems that can be abstracted as graph problems. For instance, think about shortest path computation in routing, or about coloring and independent set computation in contention resolution.

Over the past decade, we have witnessed a renaissance in the area of Distributed Graph Algorithms, with tremendous progress in many directions and solutions for a number of decades-old central problems. This course overviews the highlights of these results. The course will mainly focus on one half of the field, which revolves around locality and local problems. The other half, which relates to the issue of congestion and dealing with limited bandwidth in global problems, will not be addressed in this offering of the course.

The course will cover a sampling of the recent developments (and open questions) at the frontier of research of distributed graph algorithms. The material will be based on a compilation of recent papers in this area, which will be provided throughout the semester. The tentative list of topics includes:
- The shattering technique for local graph problems and its necessity
- Lovasz Local Lemma algorithms, their distributed variants, and distributed applications
- Distributed Derandomization
- Distributed Lower bounds
- Graph Coloring
- Complexity Hierarchy and Gaps
- Primal-Dual Techniques
Voraussetzungen / BesonderesThe class assumes no knowledge in distributed algorithms/computing. Our only prerequisite is the undergraduate class Algorithms, Probability, and Computing (APC) or any other course that can be seen as the equivalent. In particular, much of what we will discuss uses randomized algorithms and therefore, we will assume that the students are familiar with the tools and techniques in randomized algorithms and analysis (to the extent covered in the APC class).
263-4656-00LDigital Signatures Information W4 KP2V + 1AD. Hofheinz
KurzbeschreibungDigital signatures as one central cryptographic building block. Different security goals and security definitions for digital signatures, followed by a variety of popular and fundamental signature schemes with their security analyses.
LernzielThe student knows a variety of techniques to construct and analyze the security of digital signature schemes. This includes modularity as a central tool of constructing secure schemes, and reductions as a central tool to proving the security of schemes.
InhaltWe will start with several definitions of security for signature schemes, and investigate the relations among them. We will proceed to generic (but inefficient) constructions of secure signatures, and then move on to a number of efficient schemes based on concrete computational hardness assumptions. On the way, we will get to know paradigms such as hash-then-sign, one-time signatures, and chameleon hashing as central tools to construct secure signatures.
LiteraturJonathan Katz, "Digital Signatures."
Voraussetzungen / BesonderesIdeally, students will have taken the D-INFK Bachelors course "Information Security" or an equivalent course at Bachelors level.
272-0302-00LApproximations- und Online-Algorithmen Information W5 KP2V + 1U + 1AH.‑J. Böckenhauer, D. Komm
KurzbeschreibungDiese Lerneinheit behandelt approximative Verfahren für schwere Optimierungsprobleme und algorithmische Ansätze zur Lösung von Online-Problemen sowie die Grenzen dieser Ansätze.
LernzielAuf systematische Weise einen Überblick über die verschiedenen Entwurfsmethoden von approximativen Verfahren für schwere Optimierungsprobleme und Online-Probleme zu gewinnen. Methoden kennenlernen, die Grenzen dieser Ansätze aufweisen.
InhaltApproximationsalgorithmen sind einer der erfolgreichsten Ansätze zur Behandlung schwerer Optimierungsprobleme. Dabei untersucht man die sogenannte Approximationsgüte, also das Verhältnis der Kosten einer berechneten Näherungslösung und der Kosten einer (nicht effizient berechenbaren) optimalen Lösung.
Bei einem Online-Problem ist nicht die gesamte Eingabe von Anfang an bekannt, sondern sie erscheint stückweise und für jeden Teil der Eingabe muss sofort ein entsprechender Teil der endgültigen Ausgabe produziert werden. Die Güte eines Algorithmus für ein Online-Problem misst man mit der competitive ratio, also dem Verhältnis der Kosten der berechneten Lösung und der Kosten einer optimalen Lösung, wie man sie berechnen könnte, wenn die gesamte Eingabe bekannt wäre.

Inhalt dieser Lerneinheit sind
- die Klassifizierung von Optimierungsproblemen nach der erreichbaren Approximationsgüte,
- systematische Methoden zum Entwurf von Approximationsalgorithmen (z. B. Greedy-Strategien, dynamische Programmierung, LP-Relaxierung),
- Methoden zum Nachweis der Nichtapproximierbarkeit,
- klassische Online-Probleme wie Paging oder Scheduling-Probleme und Algorithmen zu ihrer Lösung,
- randomisierte Online-Algorithmen,
- Entwurfs- und Analyseverfahren für Online-Algorithmen,
- Grenzen des "competitive ratio"- Modells und Advice-Komplexität als eine Möglichkeit, die Komplexität von Online-Problemen genauer zu messen.
LiteraturDie Vorlesung orientiert sich teilweise an folgenden Büchern:

J. Hromkovic: Algorithmics for Hard Problems, Springer, 2004

D. Komm: An Introduction to Online Computation: Determinism, Randomization, Advice, Springer, 2016

Zusätzliche Literatur:

A. Borodin, R. El-Yaniv: Online Computation and Competitive Analysis, Cambridge University Press, 1998
401-3052-05LGraph Theory Information W5 KP2V + 1UB. Sudakov
KurzbeschreibungBasic notions, trees, spanning trees, Caley's formula, vertex and edge connectivity, 2-connectivity, Mader's theorem, Menger's theorem, Eulerian graphs, Hamilton cycles, Dirac's theorem, matchings, theorems of Hall, König and Tutte, planar graphs, Euler's formula, basic non-planar graphs, graph colorings, greedy colorings, Brooks' theorem, 5-colorings of planar graphs
LernzielThe students will get an overview over the most fundamental questions concerning graph theory. We expect them to understand the proof techniques and to use them autonomously on related problems.
SkriptLecture will be only at the blackboard.
LiteraturWest, D.: "Introduction to Graph Theory"
Diestel, R.: "Graph Theory"

Further literature links will be provided in the lecture.
Voraussetzungen / BesonderesStudents are expected to have a mathematical background and should be able to write rigorous proofs.


NOTICE: This course unit was previously offered as 252-1408-00L Graphs and Algorithms.
401-3903-11LGeometric Integer ProgrammingW6 KP2V + 1UJ. Paat
KurzbeschreibungInteger programming is the task of minimizing a linear function over all the integer points in a polyhedron. This lecture introduces the key concepts of an algorithmic theory for solving such problems.
LernzielThe purpose of the lecture is to provide a geometric treatment of the theory of integer optimization.
InhaltKey topics are:

- Lattice theory and the polynomial time solvability of integer optimization problems in fixed dimension.

- Structural properties of integer sets that reveal other parameters affecting the complexity of integer problems

- Duality theory for integer optimization problems from the vantage point of lattice free sets.
Skriptnot available, blackboard presentation
LiteraturLecture notes will be provided.

Other helpful materials include

Bertsimas, Weismantel: Optimization over Integers, 2005

and

Schrijver: Theory of linear and integer programming, 1986.
Voraussetzungen / Besonderes"Mathematical Optimization" (401-3901-00L)
272-0300-00LAlgorithmik für schwere Probleme Information
Findet dieses Semester nicht statt.
Diese Lerneinheit beinhaltet die Mentorierte Arbeit Fachwissenschaftliche Vertiefung mit pädagogischem Fokus Informatik A n i c h t !
W5 KP2V + 1U + 1A
KurzbeschreibungDiese Lerneinheit beschäftigt sich mit algorithmischen Ansätzen zur Lösung schwerer Probleme, insbesondere mit exakten Algorithmen mit moderat exponentieller Laufzeit und parametrisierten Algorithmen.

Eine umfassende Reflexion über die Bedeutung der vorgestellten Ansätze für den Informatikunterricht an Gymnasien begleitet den Kurs.
LernzielAuf systematische Weise eine Übersicht über die Methoden zur Lösung schwerer Probleme kennen lernen. Vertiefte Kenntnisse im Bereich exakter und parameterisierter Algorithmen erwerben.
InhaltZuerst wird der Begriff der Berechnungsschwere erläutert (für die Informatikstudierenden wiederholt). Dann werden die Methoden zur Lösung schwerer Probleme systematisch dargestellt. Bei jeder Algorithmenentwurfsmethode wird vermittelt, was sie uns garantiert und was sie nicht sichern kann und womit wir für die gewonnene Effizienz bezahlen. Ein Schwerpunkt liegt auf exakten Algorithmen mit moderat exponentieller Laufzeit und auf parametrisierten Algorithmen.
SkriptUnterlagen und Folien werden zur Verfügung gestellt.
LiteraturJ. Hromkovic: Algorithmics for Hard Problems, Springer 2004.

R. Niedermeier: Invitation to Fixed-Parameter Algorithms, 2006.

M. Cygan et al.: Parameterized Algorithms, 2015.

F. Fomin, D. Kratsch: Exact Exponential Algorithms, 2010.
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