by Mark C. Wilson | Apr 12, 2013
Speaker: Arkadii Slinko
Affiliation: The University of Auckland
Title: Secret sharing schemes (an elementary introduction)
Date: Tuesday, 7 May 2013
Time: 4:00 pm
Location: Room 6115, Owen Glenn Building
Certain cryptographic keys, such as missile launch codes, numbered bank accounts and the secret decoding exponent in an RSA public key cryptosystem, are so important that they present a dilemma. If too many copies are distributed, one may be leaked. If too few, they might all be lost or accidentally destroyed. Secret sharing schemes invented by Shamir (1979) and Blakley (1979) address this problem, and allow arbitrarily high levels of confidentiality and reliability to be achieved. A secret sharing scheme `divides’ the secret S into `shares’ – one for every user – in such a way that S can be easily reconstructable by any authorised subset of users, but an unauthorised subset of users can extract absolutely no information about S. A secret sharing scheme, for example, can secure a secret over multiple servers and it remains recoverable despite multiple server failures.
Secret sharing schemes are a sort of cooperative games where the information and not money is being distributed among players. The set of authorised coalitions of a secret sharing scheme is a simple game so there is a rich connection to the theory of games.
In my talk I will give an elementary introduction to secret sharing.
by Mark C. Wilson | Mar 26, 2013
Speaker: Dr Ben Greiner
Affiliation: University of New South Wales
Title: Bargaining, Asymmetric Information, and Communication – An Experiment
Date: Tuesday, 9 Apr 2013
Time: 12:00 pm
Location: Lab 04, Level 0, Owen Glenn Building
(note the unusual time and venue)
This paper explores the effect of communication on negotiation behavior in a stylized bargaining environment with asymmetric information. In particular, we study an Ultimatum Game in which the total amount to be bargained over (the pie) might be unknown to one party. We systematically vary whether both parties are informed about the pie size (baseline), or only the proposer, or only the responder. In addition, we vary whether there is no communication before the bargaining procedure, or whether the informed party can send a message about the pie size before decisions are made. In one communication condition, the message sender is free to choose the correct or the wrong message (cheap talk), while in the second communication condition the sender can only choose whether to reveal or not to reveal the true pie size (“true talk”). We find that contrary to the theoretical prediction cheap talk has a significant positive effect on efficiency, while true talk is less effective than expected.
by Mark C. Wilson | Mar 5, 2013
Speaker: Kathryn E. Lenz
Affiliation: Department of Mathematics and Statistics, University of Minnesota Duluth
Title: Voting Methods for Municipal Elections: Propaganda, Field Experiments and what USA Voters Want from an Election Algorithm
Date: Tuesday, 19 Mar 2013
Time: 4:00 pm
Location: Room 6115, Owen Glenn Building
Within the past two decades various cities across the USA have experimented with instant run-off voting (IRV) for political elections. These experiments demonstrate a public desire for replacing plurality voting with a better method and they give insight into what voters want from an election algorithm. This talk will briefly review several standard election algorithms, properties and public reaction to them. Examples will be given of IRV city election results, pro-IRV propaganda found on websites, misrepresentations in newspaper opinion pieces and discussions with mathematicians and non-mathematicians. Though disheartening, misinformation about IRV propagating in the public arena and suppression of full IRV election results do provide opportunities for the mathematically minded to engage in civic dialogue and to raise awareness concerning election algorithm options.
Slides are available.
by Mark C. Wilson | Feb 27, 2013
Speaker: Matthias Ehrgott
Affiliation: The University of Auckland
Title: Multiobjective Optimization for Supporting Radiation Therapy Treatment Planning
Date: Tuesday, 5 Mar 2013
Time: 4:00 pm
Location: Room 6115, Owen Glenn Building
The choice of a plan for radiotherapy treatment for an individual cancer patient requires the careful trade-off between the goals of delivering a sufficiently high radiation dose to the tumour and avoiding irradiation of critical organs and normal tissue. To support the treatment planner in this task it is necessary to visualize these trade-offs. The treatment planning problem can be formulated as a multi-objective optimization problem. We present a method to compute the optimal trade-offs for this problem and plot them in three dimensions. Furthermore, by computing a finite set of treatment plans that are well distributed across the entire trade-off surface, we support the treatment planner in identifying the best available plan for the patient under consideration.
Slides are available
by Mark C. Wilson | Feb 11, 2013
The title of an article in The Economist. Very relevant to CMSS.
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