V ponedeljek, 5.1.2009, bosta ob 16. uri  v  mali predavalnici  Fakultete za matematiko, naravoslovje in inforamcijske tehnologije Univerze na Primorskem, Glagoljaška 8,  Koper predavanji v okviru skupnega SEMINARJA ZA MATEMATICNE IN RAČUNALNIŠKE ZNANOSTI Oddelka za matematiko in računalništvo UP FAMNIT, Oddelka za matematiko in računalništvo UP PINT, Oddelka za matematiko in računalništvo UP PEF ter Oddelkov za matematiko in teoretično računalništvo IMFM.
Dnevni red:

16:00 -- 17:00

Predavatelj: Darko Dimitrov

Naslov: Bounds on the quality of the PCA bounding boxes

Povzetek:

Principal component analysis (PCA) is commonly used to compute a bounding
box of a point set. In this talk, we consider the quality of the PCA bounding boxes,
presenting bounds on the worst case ratio of the volume of the PCA bounding box and the
volume of the minimum-volume bounding box. We show examples of discrete point sets where
the worst case ratio tends to infinity. Thus, we concentrate our attention on PCA
bounding boxes for continuous sets, especially for the convex hull of a point set,
obtaining several variants of continuous PCA. For those variants, we present lower bounds
in arbitrary dimension, and upper bounds in R^2 and R^3.

17:00 -- 18:00

Predavatelj: Klavdija Kutnar
 

Title: EDGE-TRANSITIVE ROSE WINDOW GRAPHS

Abstract:

Given natural numbers $n \ge 3$ and $1 \le a,r \le n-1$,
the {\em rose window graph} $R_n(a,r)$ %, introducted by Steve Wilson,
is a quartic  graph with vertex set $\{ x_i \, |  \, i \in \ZZ_n \}
\cup \{  y_i \,  |  \,  i \in \ZZ_n \}$
and edge set $\{\{x_i,x_{i + 1}\} \mid i \in \ZZ_n \}  \cup
\{\{y_i,y_{i + r}\} \mid i \in \ZZ_n \}\cup
\{\{x_i,y_i\} \mid i \in \ZZ_n \} \cup \{\{x_{i+a},y_{i}\} \mid i \in
\ZZ_n \}$.

In this talk I will present the classification of  edge-transitive
rose window graphs which confirms Steve Wilson's conjectures
on rose window graphs. This is a joint work with Istvan Kovacs,
Dragan Marušič and Janos Ruff.

Vabljeni!