In large-scale unconstrained optimization algorithms such as limited memory BFGS (LBFGS), a common subproblem is a line search minimizing the loss function along a descent direction. Commonly used line searches iteratively find an approximate solution for which the Wolfe conditions are satisfied, typically requiring multiple function and gradient evaluations per line search, which is expensive ...

We evaluate 179 classifiers arising from 17 families (discriminant analysis, Bayesian, neural networks, support vector machines, decision trees, rule-based classifiers, boosting, bagging, stacking, random forests and other ensembles, generalized linear models, nearestneighbors, partial least squares and principal component regression, logistic and multinomial regression, multiple adaptive regre...

We have used the data from the PASCAL CHiME challenge with the goal of training a Support Vector Machine (SVM) to estimate a noise mask that labels time-frames/frequency-bins of the audio as 'reliable' or 'unreliable'. This noise mask could be used by another block in the signal processing pipeline to treat the unreliable data as missing and then replace the missing data with an estimate of the...

Most research on author identification considers large texts. Not many research is done on author identification for short texts, while short texts are commonly used since the rise of digital media. The anonymous nature of internet applications offers possibilities to use the internet for illegitimate purposes. In these cases, it can be very useful to be able to predict who the author of a mess...

Head movements are the most frequent gestures in face-to-face communication, and important for feedback giving (Allwood, 1988; Yngve, 1970; Duncan, 1972), and turn management (McClave, 2000).Their automatic recognition has been addressed by many multimodal communication researchers (Heylen et al., 2007; Paggio and Navarretta, 2011; Morency et al., 2007). The method for automatic head movement a...

Current hierarchical text categorization (HTC) methods mainly fall into three directions: (1) Flat one-vs.-all approach, which flattens the hierarchy into independent nodes and trains a binary one-vs.-all classifier for each node. (2) Top-down method, which uses the hierarchical structure to decompose the entire problem into a set of smaller subproblems, and deals with such sub-problems in top-...

In TRECVID 2007 high-level feature (HLF) detection, we extend the well-known LIBSVM and develop a toolkit specifically for HLF detection. The package shortens the learning time and provides a framework for researchers to easily conduct experiments. We efficiently and effectively aggregate detectors of training past data to achieve better performances. We propose post-processing techniques, conc...

References [1] Hubel, D.H., Wiesel, T.N.: Receptive fields and functional architecture of monkey striate cortex. J. Physiol. (Lond.) 195, 215–243 (1968). [2] K. Fukushima: Neocognitron: A self-organizing neural network model for a mechanism of pattern recognition unaffected by shift in position, Biological Cybernetics, 36(4), pp. 193-202 (April 1980). [3] Riesenhuber, M. & Poggio, T. (1999). Hi...