Algorithms Algorithms Gerth Stlting Brodal Overview Overview - - PowerPoint PPT Presentation

Master Thesis Preparation

Algorithms Algorithms

Gerth Stølting Brodal

Overview Overview

Algo Algorit rithm hms s gr grou

• up

p at at DAIMI DAIMI

• Who?
• Where?
• Courses
• Research

Mas Maste ter r th thes esis is in Algor in Algorithms ithms

• Types of thesis
• Recent thesis topics

Algori Algorithms thms Group Group – Who? Who?

Fa Facu cult lty Lars Arge Gerth Stølting Brodal Gudmund Skovbjerg Frandsen Peter Bro Miltersen Christian Nørgaard Storm Pedersen (Erik Meineche Schmidt) (Sven Skyum) Rese esear arche hers Thomas Mailund Henrik Blunck Ph Ph.d. .d. stud studen ents ts ~ 10 Maste Master s r stud tuden ents ts ~ 20

Algori Algorithms thms Group Group – Where Where ?

Algorithms (Turing 2) Arge, Brodal, Frandsen, Miltersen, Blunck BioInformatics (Building 090) Pedersen, Mailund

Intr Introd

• duc

ucto tory ry

• Programming 2
• Frandsen
• Algorithms and data structures
• Brodal, Schmidt
• Machine architecture/Operating systems - Pedersen

Adv Advan ance ced

• Optimization/Combinatorial search
• Miltersen
• Computational geometry
• Arge, Brodal
• I/O algorithms
• Arge, Brodal
• Advanced data structures
• Arge, Brodal
• Dynamic algorithms
• Frandsen
• Randomized algorithms
• Frandsen
• String algorithms
• Pedersen
• Algorithms in bioinformatics
• Pedersen
• Complexity theory
• Miltersen
• Data compression (loseless/lossy)
• Miltersen
• Algorithmic game playing
• Miltersen

Algori Algorithms thms Group Group – Courses Courses

I/O algorithms Computational geometry Data structures String algorithms Complexity theory Data compression Optimization Algebraic algorithms BioInformatics Graph algorithms Dynamic algorithms Randomized algorithms Algorithmic game theory Arge Brodal Frandsen Miltersen Pedersen Mailund

Subset of research interests Solid lines = major interst

Algorithms Algorithms Group Group – Research Research

Algorithms Algorithms Group Group – Research Research

• Theoretical computer science
• Tool development

– BioInformatics, I/O algorithms

• Algorithm engineering

– primarily in relation to thesis work

• Algorithms and complexity research seminar

– www.daimi.au.dk/~gerth/alcom-seminar/

Algori Algorithm thm Research Research

– a typica

a typical res l result sta ult stateme tement nt

Cache-Oblivious Data Structures and Algorithms for Undirected Breadth-First Search and Shortest Paths,

• G. S. Brodal, R. Fagerberg, U. Meyer, N. Zeh. In Proc. 9th Scandinavian Workshop on Algorithm Theory,

volume 3111 of Lecture Notes in Computer Science, pages 480-492. Springer Verlag, Berlin, 2004.

Results

Algori Algorithm thm Research Research

– an

anoth

• ther typical result

er typical result

On the Adaptiveness of Quicksort, G. S. Brodal, R. Fagerberg, G. Moruz. In Proc. 7th Workshop on Algorithm Engineering and Experiments, 2005.

Comparisons by Quicksort Element swaps Running time

Types of Algorithmic Thesis

• Solve a concrete problem

…using algorithmic techniques

• Survey of a research area
• Implement a technical paper

...fill in the missing details ...perform experiments

• Explain all (missing) details in a technical paper

...how 8 pages become +100 pages

• Experimental comparison of several algorithms
• The clever idea: Describe a new algorithm

Master Thesis in Algorithms

The hesis sis wor

• rk
• Large fraction of time spend on trying to

understand technical complicated constructions

• Implementations are often an ”existence proof” –

most algorithm authors do not implement their algorithms (did they ever think about the missing details?)

• Hard to convince friends that it took you a year to

understand an 8 page paper...

Hidden work...

! Warning ! Need to understand another paper first ! Warning ! Nontrivial construction ahead of you

Algorith Algorithms Master ms Master Theses Theses

Refined Buneman Trees Pedersen Integer Sorting Fagerberg Trade-offs for Internal and External Memory Dictionaries Fagerberg A Survey of Density Keeping Algorithms Fagerberg Shortest Paths in Directed Graphs Fagerberg Approksimative afstande i planare grafer Brodal Vedligeholdelse af sammenhængskomponenter i dynamiske grafer Frandsen Maksimale par og suffikstræer Pedersen Skjulte Markov modeller og genidentifikation Pedersen Towards practical deterministic extractors Miltersen Engineering cache-oblivious sorting algorithms Fagerberg/ Brodal Analyse og håndtering af genekspressionsdata Pedersen Dynamisk Pattern Matching Frandsen Redigeringsafstande imellem niveau-strenge Frandsen Automated Layout of Classified Ads Brodal