Vaclav Petricek

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This paper presents a game theoretic analysis of the generalized second price auction that Yahoo operates to sell sponsored search listings on its search engine. We present results that indicate that this auction has a multiplicity of Nash equilibria. We also show that weak dominance arguments do not in general select a unique Nash equilibrium. We then(More)
In this paper we describe preliminary work that examines whether statistical properties of the structure of websites can be an informative measure of their quality. We aim to develop a new method for evaluating e-government. E-government websites are evaluated regularly by consulting companies, international organizations and academic researchers using a(More)
This paper examines the difference and similarities between the two on-line computer science citation databases DBLP and CiteSeer. The database entries in DBLP are inserted manually while the CiteSeer entries are obtained autonomously via a crawl of the Web and automatic processing of user submissions. CiteSeer’s autonomous citation database can be(More)
We examine the difference and similarities between two on-line computer science citation databases DBLP and CiteSeer. The database entries in DBLP are inserted manually while the CiteSeer entries are obtained autonomously. We show that the CiteSeer database contains considerably fewer single author papers. This bias can be modeled by an exponential process(More)
Flash-freezing is a technique that is commonly used nowadays to collect diffraction data for X-ray structural analysis. It can affect both the crystal and molecular structure and the molecule's surface, as well as the internal cavities. X-ray structural data often serve as a template for the protein receptor in docking calculations. Thus, the size and shape(More)
Structure analysis of ground state (GS) and two light-induced (SI and SII) metastable linkage NO isomers of [Ru(py)4Cl(NO)](PF6)2.0.5H2O is presented. Illumination of the crystal by a laser with lambda = 473 nm at T = 80 K transfers around 92% of the NO ligands from Ru-N-O into the isomeric configuration Ru-O-N (SI). A subsequent irradiation with lambda =(More)
The topological structures of the Internet and the Web have received considerable attention. However, there has been little research on the topological properties of individual web sites. In this paper, we consider whether web sites (as opposed to the entire Web) exhibit structural similarities. To do so, we exhaustively crawled 18 web sites as diverse as(More)
Bootstrapping is a useful technique for estimating the uncertainty of a predictor, for example, confidence intervals for prediction. It is typically used on small to moderate sized datasets, due to its high computation cost. This work describes a highly scalable online bootstrapping strategy, implemented inside Vowpal Wabbit, that is several times faster(More)
Superspace symmetry has been for many years the standard approach for the analysis of non-magnetic modulated crystals because of its robust and efficient treatment of the structural constraints present in incommensurate phases. For incommensurate magnetic phases, this generalized symmetry formalism can play a similar role. In this context we review from a(More)