Algorithms for security in robotics and networks

The dissertation presents algorithms for robotics and security. The first chapter gives an overview of the area of visibility-based pursuit-evasion. The following two chapters introduce two specific algorithms in that area. The algorithms are based on research done together with Dr. Giora Slutzki and Dr. Steven LaValle. Chapter 2 presents a polynomial-time algorithm for clearing a polygon by a single 1-searcher. The result is extended to a polynomial-time algorithm for a pair of 1-searchers in Chapter 3.;Chapters 4 and 5 contain joint research with Dr. Srini Tridandapani, Dr. Jason Jue and Dr. Michael Borella in the area of computer networks. Chapter 4 presents a method of providing privacy over an insecure channel which does not require encryption. Chapter 5 gives approximate bounds for the link utilization in multicast traffic

Applying A Normalized Compression Metric To The Measurement Of Dialect Distance

The paper discusses the application of a similarity metric based on compression to the measurement of the distance among Bulgarian dia- lects. The similarity metric is de ned on the basis of the notion of Kolmo- gorov complexity of a le (or binary string). The application of Kolmogorov complexity in practice is not possible because its calculation over a le is an undecidable problem. Thus, the actual similarity metric is based on a real life compressor which only approximates the Kolmogorov complexity. To use the metric for distance measurement of Bulgarian dialects we rst represent the dialectological data in such a way that the metric is applicable. We propose two such representations which are compared to a baseline distance between dialects. Then we conclude the paper with an outline of our future work

Using the linguistic knowledge in BulTreeBank for the selection of the correct parses

Proceedings of the Ninth International Workshop on Treebanks and Linguistic Theories. Editors: Markus Dickinson, Kaili Müürisep and Marco Passarotti. NEALT Proceedings Series, Vol. 9 (2010), 163-174. © 2010 The editors and contributors. Published by Northern European Association for Language Technology (NEALT) http://omilia.uio.no/nealt . Electronically published at Tartu University Library (Estonia) http://hdl.handle.net/10062/15891

Diet and foraging habitats of non-breeding white storks (Ciconia ciconia) in Bulgaria

The diet of non-breeding White Storks was studied by pellet analysis and included mainly insects (99.9%, n=28947) with a predominance of grasshoppers (Orthoptera, 76.1%), and beetles (Coleoptera, 26.1%). The bush crickets Decticus albifrons/verrucivorus were the most numerous prey (29.9% by items), occurring in almost all pellets (98% occurrence in pellets, n=147) and predominating in half of them (49.7%). The grasshopper associations in the pellets specify foraging mainly in mesophytic grasslands that usually replace abandoned fields and overgrown pastures with a low level of grazing. The xerophytic grass-shrubby habitats, not rare on stony terrains, were of less importance, providing around 20% by prey. The typical aquatic inhabitants and the use of carrion around villages were exceptions in the study diet. The number of innutritious materials in the pellets rose when the White Storks hunted on nippy and agile grasshoppers and decreased when the main pray was slower beetles taken from the ground. The roosting of non-breeding White Storks disappeared when their preferred feeding habitats were ploughed up in the following years

Experimental study on HHO electrolyzer efficiency – influence of the number of plates and their distance

The present paper explores the factors influencing the efficiency of an HHO-gas-electrolyzer. The experiments were held in the respective laboratory at the Technical University of Varna with a principal focus on two of these factors –i.e., distance between the plates and the number of plates in a wet electrolyzer. The scientific tests were performed with all the remaining conditions being held constant and the appropriate results were obtained and visualized to disclose the most efficient electrolyzer setups

Multicomponent polymer system based on hydrophilized unsaturated polyester resin

This work is a follow-up of the study of hydrophilization of unsaturated polyester resin (UPER) with sodium hydroxide. Different amounts of water were added to the hydrophilized unsaturated polyester resin (HU­PER) so obtained and their effects on curing kinetics were studied. The tensile strength and energy to break these compositions are presented depending on the amount of the specified components. A possibility for using different fillers, coal ash in particular, and their mixing with HUPER was sought. The effect of each of the components on the curing kinetics of the respective compositions, and the effect of all components when consecutively mixed in the multicomponent composition was examined. We sought an opportunity for the application of some of the compositions as substituents of dental cast models