Features and Agreement

This paper compares the consistency-based account of agreement phenomena in `unification-based' grammars with an implication-based account based on a simple feature extension to Lambek Categorial Grammar (LCG). We show that the LCG treatment accounts for constructions that have been recognized as problematic for `unification-based' treatments

Fat Fisher Zeroes

We show that it is possible to determine the locus of Fisher zeroes in the thermodynamic limit for the Ising model on planar (``fat'') phi4 random graphs and their dual quadrangulations by matching up the real part of the high and low temperature branches of the expression for the free energy. The form of this expression for the free energy also means that series expansion results for the zeroes may be obtained with rather less effort than might appear necessary at first sight by simply reverting the series expansion of a function g(z) which appears in the solution and taking a logarithm. Unlike regular 2D lattices where numerous unphysical critical points exist with non-standard exponents, the Ising model on planar phi4 graphs displays only the physical transition at c = exp (- 2 beta) = 1/4 and a mirror transition at c=-1/4 both with KPZ/DDK exponents (alpha = -1, beta = 1/2, gamma = 2). The relation between the phi4 locus and that of the dual quadrangulations is akin to that between the (regular) triangular and honeycomb lattices since there is no self-duality.Comment: 12 pages + 6 eps figure

Application of multi-agent games to the prediction of financial time-series

We report on a technique based on multi-agent games which has potential use in the prediction of future movements of financial time-series. A third-party game is trained on a black-box time-series, and is then run into the future to extract next-step and multi-step predictions. In addition to the possibility of identifying profit opportunities, the technique may prove useful in the development of improved risk management strategies.Comment: Work presented at the NATO Workshop on Econophysics. Prague (Feb 2001). To appear in Physica

Advances in quantum machine learning

Here we discuss advances in the field of quantum machine learning. The following document offers a hybrid discussion; both reviewing the field as it is currently, and suggesting directions for further research. We include both algorithms and experimental implementations in the discussion. The field's outlook is generally positive, showing significant promise. However, we believe there are appreciable hurdles to overcome before one can claim that it is a primary application of quantum computation.Comment: 38 pages, 17 Figure

Distribution and Population Characteristics of Lower Walleye in the Eleven Point River, Arkansas

Walleye Sander vitreus (Mitchill) distributions and ecology have been poorly studied in southern river basins. We studied the longitudinal distribution and population characteristics of walleye in an unregulated river within the Ozark region of the U.S., the lower Eleven Point River, Arkansas, which has high species diversity. Walleye were collected in a 60 km segment of the river by daytime boat electrofishing over a three year period (2002-2004). Catch rates, growth rates and size structure were high relative to other streams studied in North America. Catch per effort ( = 5.2/h) was similar seasonally, spatially and among years. Proportional stock structures were quite high ( = 80), with numerous fish collected over 600 mm total length, 4 kg in mass and greater than 10 years of age. Relative weights of all length groups (stock size, proportional size structure, relative size structure) were at or greater than 90. Stomach contents of walleye were more suggestive of a generalist strategy in a stream of high species diversity, as compared to the targeting of a single numerically dominant prey, which is common in lentic systems

Parsing eye-tracking data of variable quality to provide accurate fixation duration estimates in infants and adults

Researchers studying infants’ spontaneous allocation of attention have traditionally relied on hand-coding infants’ direction of gaze from videos; these techniques have low temporal and spatial resolution and are labor intensive. Eye-tracking technology potentially allows for much more precise measurement of how attention is allocated at the subsecond scale, but a number of technical and methodological issues have given rise to caution about the quality and reliability of high temporal resolution data obtained from infants. We present analyses suggesting that when standard dispersal-based fixation detection algorithms are used to parse eye-tracking data obtained from infants, the results appear to be heavily influenced by interindividual variations in data quality. We discuss the causes of these artifacts, including fragmentary fixations arising from flickery or unreliable contact with the eyetracker and variable degrees of imprecision in reported position of gaze. We also present new algorithms designed to cope with these problems by including a number of new post hoc verification checks to identify and eliminate fixations that may be artifactual. We assess the results of our algorithms by testing their reliability using a variety of methods and on several data sets. We contend that, with appropriate data analysis methods, fixation duration can be a reliable and stable measure in infants. We conclude by discussing ways in which studying fixation durations during unconstrained orienting may offer insights into the relationship between attention and learning in naturalistic settings