This thesis describes a process of cracking a password, existing types of attacks and generating passwords using probabilistic grammar. This grammar can be used as an attack that works on the basis of learning from an existing list of passwords and generating them by using constructed context-free grammar from the learning phase. The core of this thesis is the design and implementation of distribution solution for this type of attack. Implementation includes refactoring of existing solution and optimization to maximize use of every available resource.

A small number of eastern north Pacific gray whales (Eschrichtius robustus), known as the Pacific Coastal Feeding Group (PCFG) forage during the summer months in the coastal waters between California and Alaska. Although several studies have analyzed the population structure of the PCFG, maternal learning and predator/prey dynamics have not been studied in detail. In this study I characterize fine scale habitat use and site fidelity of eastern north Pacific gray whales in one foraging site within the PCFG’s foraging range. I approach this study by examining site fidelity to Clayoquot Sound in increasing detail at different time scales. Using the variability recorded in 17 field seasons of whale census surveys (1997-2013) as a proxy for fluctuations in prey, I suggest that the combination of physical properties of the study area and the life history characteristics of the primary prey species type enable Clayoquot Sound to persist as a foraging site through time. The analysis of photographic identification data collected between 1998-2013 indicates that Clayoquot Sound is one site within a larger foraging range, and that annual fluctuations in prey density are related to site fidelity and residency time. By identifying cow/calf pairs using photographic identification data collected between 1998-2013 I characterize internal recruitment via maternal learning within Clayoquot Sound. A calf’s site fidelity is related to its mother’s site fidelity, but its residency time is related to annual fluctuations in prey density. In contrast, a cow’s residency time is not related to changes in prey, but increases in duration when accompanied by a calf. The interplay between fluctuations in prey productivity, and the age and gender of individuals, are the variables that most likely influence the distribution of PCFG whales intra- and inter-annually. / Graduate / 0306

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This thesis describes passwords cracking using probabilistic context-free grammars, specifically PCFG Cracker tool. The aim of the thesis is to design and implement enhancements to this tool, which reduce the size of output dictionaries while maintaining acceptable success rate. This work also solves critical parts in the tool that slow down the overall duration of the program. Another goal of the thesis is to analyze and implement targeted attack dictionaries that increase the scope and success rate of generated passwords.

Master’s thesis describes theoretical basics, solution design, and implementation of constituency (phrasal) parser for Czech language, which is based on a part of speech association into phrases. Created program works with manually built and annotated Czech sample corpus to generate probabilistic context free grammar within runtime machine learning. Parser implementation, based on extended CKY algorithm, then for the input Czech sentence decides if the sentence can be generated by the created grammar and for the positive cases constructs the most probable derivation tree. This result is then compared with the expected parse to evaluate constituency parser success rate.