Operators for Similarity Search: Semantics, Techniques and Usage Scenarios

This book provides a comprehensive tutorial on similarity operators. The authors systematically survey the set of similarity operators, primarily focusing on their semantics, while also touching upon mechanisms for processing them effectively.

The book starts off by providing introductory material on similarity search systems, highlighting the central role of similarity operators in such systems. This is followed by a systematic categorized overview of the variety of similarity operators that have been proposed in literature over the last two decades, including advanced operators such as RkNN, Reverse k-Ranks, Skyline k-Groups and K-N-Match. Since indexing is a core technology in the practical implementation of similarity operators, various indexing mechanisms are summarized. Finally, current research challenges are outlined, so as to enable interested readers to identify potential directions for future investigations.

In summary, this book offers a comprehensive overview of the field of similarity search operators, allowing readers to understand the area of similarity operators as it stands today, and in addition providing them with the background needed to understand recent novel approaches.

Evidence of syntactic working memory usage in MEG data

While reading times are often used to measure working memory load, frequency effects (such as surprisal or n-gram frequencies) also have strong confounding effects on reading times. This work uses a naturalistic audio corpus with magnetoencephalographic (MEG) annotations to measure working memory load during sentence processing. Alpha oscillations in posterior regions of the brain have been found to correlate with working memory load in non-linguistic tasks (Jensen et al., 2002), and the present study extends these findings to working memory load caused by syntactic center embeddings. Moreover, this work finds that frequency effects in naturally-occurring stimuli do not significantly contribute to neural oscillations in any frequency band, which suggests that many modeling claims could be tested on this sort of data even without controlling for frequency effects.

The effect of preferential paw usage on dogs' (Canis familiaris) performance in a manipulative problem-solving task

In a number of species, individuals showing lateralized hand/paw usage (i.e. the preferential use of either the right or left paw) compared to ambilateral individuals have been shown to be more proactive in novel situations. In the current study we used an established test to assess preferential paw usage in dogs (the Kong test) and then compared the performance of ambilateral and lateralized dogs as well as left- vs. right-pawed dogs in a novel manipulative problem solving task. Results showed an equal proportion of ambilateral and lateralized dogs but contrary to predictions non-lateralized dogs were faster at accessing the apparatus in test trials. No differences emerged between right- and left-pawed dogs. Results are discussed in relation to previous studies on lateralization. © 2013 Elsevier B.V.