1 heinz nixdorf institut university of paderborn algorithms und complexity seminar designing...

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HEINZ NIXDORF INSTITUTUniversity of Paderborn

Algorithms und Complexity

SeminarDesigning Peer-to-Peer-Networks

Christian Schindelhauer2004-10-14

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HEINZ NIXDORF INSTITUTEUniversity of Paderborn

Algorithms und ComplexityChristian Schindelhauer

Seminar Designing P2P-Networks

Motivation

• Peer-to-Peer-Networks– We explore algorithmic problems in Peer-to-Peer networks

• Goal of this seminar: – A small research project which

• extends, • modifies, • simplifies • existing or • new concepts

– in Peer-to-Peer networks• Requirements

– Sufficient knowledge of peer-to-peer networks– E.g. the attendance of the lecture "Algorithmen für

Peer-to-Peer-Netzwerke" of last summer or similar courses– Creativity and the willingness to try out new ideas

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Goals of the Seminar

• Peer-to-Peer-Networks• Literature research in a hot topic• Develop own ideas• Present new ideas as a research proposal• Interact with others on scientific research• Checkout whether this idea works

– by mathematical analysis and/or– by empirical simulations and/or– by implementation and testing

• Evaluate other workouts• Work alone or with a partner

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Organization

• See the Web-page

http://wwwcs.upb.de/cs/ag-madh/WWW/Teaching/2004WS/Design-P2P/

• Today: Registration• Topic finding: as soon as possible (Oct. and Nov.)• Weekly meetings:

Every Thursday 2-4pmin F2.211 for topic finding and counseling

• Dec. 6th - 22th, 2004 1st presentation: research proposals• March or May, 2005 Submission of research paper• March or May, 2005 Block seminar with presentation of

research• May 2005 Evaluation, grades and comments

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The Deliverables

• 1st presentation– Duration 30 min.– Presents

• state of the art• new ideas• research plan

• 2nd presentation– Duration 30 min.– Presents the results of the research

• Research paper– max. 10 pages– shows state of the art– the outcome of the research– Did the proposed idea work? And if, how well? And if not, why

not?

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How it Counts for the Grade

• 1st presentation– 15%

• Presentation of research– 10 %

• Research paper– 75 %

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Format and Layout of Research Paper

• American English• max. 10 pages (excluding title page; including pictures, references,

tables etc.)• Accurate and correct citations and references• LATeX, BibTeX• Deliverables

– LATeX source file– BibTeX file– Compiled PDF-output

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Research Proposals

• Construct the better Peer-to-Peer-Network from scratch• Do something wild and unexpected!• Be creative!• Solve the thing that always annoyed you in your favorite Peer-to-

Peer-Network!• Show that something cannot be better as it is.• Analyze the behavior of some Peer-to-Peer-Network• Simulate the growth and shrinkage of some network• Perform (virtual) attacks on Peer-to-Peer-Networks and analyze

what happens• Make it more secure, robust, efficient, volatile, efficient, softer,

greener, faster, ...• Combine Peer-to-Peer-Networks: Chord & Skipnet, Gnutella &

Pastry, CAN & Koorde

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And if everything fails ...

• ask me.

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Research proposal: Routing in Skipnet

• Can we plug in the routing optimization techniques known from CAN, Dhash++ into Skipnet ?

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Research Proposal: Moving Peers in Chord

• If we do not hash data into Chord, but use a lexicographical ordering

• Can we achieve an efficient balancing by moving peers around?

• How can we efficiently search in this structure?

• How can we find new places for new peers?

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Research Proposal: Multiple Choice

• O(log n) tests suffice to balance the intervals in a network

• Can we cut down on these tests?

• What happens if we do not use uniform probability distributions?

• What happens if we use distributed algorithms using feedback from the first test?

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Research Proposal: Symmetric Counting

• Consider the following counting algorithm:

– Choose a random number out of [0,1] for variable xi of peer i

– If two peers communicate (randomly) then they compute the minimum of their variables and store it

– Observe: the expected value of 1/xi converges to n

• How good is this counting algorithm?• How fast does it converge?

• Are there better counting algorithms?

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To do

• Sign up for the seminar• Help to find an hour for the weekly voluntary meeting• Find your topic and discuss it with me prior to the first presentation• Do some research if you have an idea• Don’t do too much! This is NOT a master thesis! It’s a seminar.

• You may find a partner for common research

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The Schedule

Time Monday TuesdayWednesda

yThursday Friday

7 am - 9 am 4

9 am - 11 am 3 3 0,5 2 1

11am - 1pm Schindelhauer 1 1 1 1

1 pm - 2 pm Schindelhauer

2 pm - 4 pm 0,5 1 Schindelhauer Seminar 1

4 pm - 6 pm 1 Schindelhauer 1 1

6 pm - 8 pm

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HEINZ NIXDORF INSTITUTUniversity of Paderborn

Algorithms und Complexity

Thanks and let’s go!Thanks and let’s go!

Verteilte Algorithmen in Netzwerken

Christian Schindelhauer

1 heinz nixdorf institut university of paderborn algorithms und complexity seminar designing...

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