Structural graph matching using the EM algorithm and singular value decomposition

This paper describes an efficient algorithm for inexact graph matching. The method is purely structural, that is, it uses only the edge or connectivity structure of the graph and does not draw on node or edge attributes. We make two contributions: 1) commencing from a probability distribution for matching errors, we show how the problem of graph matching can be posed as maximum-likelihood estimation using the apparatus of the EM algorithm; and 2) we cast the recovery of correspondence matches between the graph nodes in a matrix framework. This allows one to efficiently recover correspondence matches using the singular value decomposition. We experiment with the method on both real-world and synthetic data. Here, we demonstrate that the method offers comparable performance to more computationally demanding method

A solid state vertex detector for study of the photoproduction of heavy flavours

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Executive Dysfunction: A Contributor to Subtypes of Violence or General Criminality?

Purpose: The adverse consequences of violence on society are tremendous. Several factors have been identified as potential contributors to violent crime, including deficits in executive functioning. Executive functioning is a term used to a describe number of higher-order cognitive abilities (e.g., working memory, inhibition) that are thought to be essential for appropriate, socially desirable behavior. The extent to which executive functions influence the occurrence of general criminality versus specific subtypes of crime is largely unknown. Of particular interest is the ability of executive functioning to distinguish between reactive and instrumental subtypes of violence. Whereas reactive violence is committed with the intention of harming the victim after perceived provocation, instrumental violence is committed with the intention of obtaining some kind of goal other than inflicting injury. Hence, the purpose of this study was clarify the relationship between executive functioning and subtypes of criminal offending, as well as to clarify the convergent and divergent validity of different indicators of executive functioning within the context of understanding crime. Method: One hundred and fifty-one adult male inmates from a federal correctional facility participated in this study. Participants completed both performance-based and self-report measures of executive functioning and their complete criminal histories were reviewed. Results: Consistent with hypotheses, executive functions were differentially related to subtypes of offending. Moreover, findings suggested that (a) performance-based tasks and self-report measures of executive functioning are unrelated to one another and are differentially related to subtypes of crime, (b) it is important to examine separate components of executive functioning rather than a composite score, and (c) the relationships between executive functions and crime are not accounted for by general intelligence. Conclusion: Taken together, this dissertation demonstrated that executive functioning is most useful when using a crime-specific approach to understanding criminality. Future research should examine this relationship longitudinally to better understand whether this is a causal link or whether there are other pathways through which executive functioning influences the likelihood of an individual engaging in specific subtypes of violence. An understanding of the variables underlying different types of violence is a necessary precursor for risk assessment and offender rehabilitation

THE ROLE OF EXECUTIVE DYSFUNCTION IN PREDICTING FREQUENCY AND SEVERITY OF VIOLENCE

The adverse consequences of violence on society are tremendous. The proportion of offenders incarcerated for violent offences is large, and the cost of keeping these offenders incarcerated is startling. Understanding and treating the causal underpinnings of violent crime is of the utmost importance for individuals and society as a whole. Several factors have been identified as potential contributors to violent crime, including cognitive deficits in executive functioning (Hoaken, Allaby, & Earle, 2007). To investigate this further, 77 offenders from Fenbrook Institution, a federal facility, were tested on a battery of executive functioning measures. Offenders were found to have broad and pervasive dysfunction in their executive abilities. In addition, specific scores from the battery were found to predict the frequency and severity of past violent offending. This speaks to the possibility of a new type of correctional rehabilitation program, one that focuses on the rehabilitation of basic executive functions

Star Formation and the Interstellar Medium In Nearby Tidal Streams (SAINTS): Spitzer Mid-infrared Spectroscopy and Imaging of Intergalactic Star-forming Objects

A spectroscopic analysis of 10 intergalactic star forming objects (ISFOs) and a photometric analysis of 67 ISFOs in a sample of 14 interacting systems is presented. The majority of the ISFOs have relative polycyclic aromatic hydrocarbon (PAH) band strengths similar to those of nearby spiral and starburst galaxies. In contrast to what is observed in blue compact dwarfs (BCDs) and local giant HII regions in the Milky Way (NGC 3603) and the Magellanic Clouds (30 Doradus and N 66), the relative PAH band strengths in ISFOs correspond to models with a significant PAH ion fraction (<50%) and bright emission from large PAHs (~100 carbon atoms). The [NeIII]/[NeII] and [SIV]/[SIII] line flux ratios indicate moderate levels of excitation with an interstellar radiation field that is harder than the majority of the Spitzer Infrared Nearby Galaxies Survey and starburst galaxies, but softer than BCDs and local giant HII regions. The ISFO neon line flux ratios are consistent with a burst of star formation < 6 million years ago. Most of the ISFOs have ~million solar masses of warm molecular hydrogen with a likely origin in photo-dissociation regions (PDRs). Infrared Array Camera photometry shows the ISFOs to be bright at 8 um, with one third having [4.5] - [8.0] > 3.7, i.e., enhanced non-stellar emission, most likely due to PAHs, relative to normal spirals, dwarf irregulars and BCD galaxies. The relative strength of the 8 um emission compared to that at 3.6 um or 24 um separates ISFOs from dwarf galaxies in Spitzer two color diagrams. The infrared power in two thirds of the ISFOs is dominated by emission from grains in a diffuse interstellar medium. One in six ISFOs have significant emission from PDRs, contributing ~30 % - 60 % of the total power. ISFOs are young knots of intense star formation.Comment: Accepted in ApJ. 49 pages 9 figure

Coding Strategies for Genetic Algorithms and Neural Nets

The interaction between coding and learning rules in neural nets (NNs), and between coding and genetic operators in genetic algorithms (GAs) is discussed. The underlying principle advocated is that similar things in "the world" should have similar codes. Similarity metrics are suggested for the coding of images and numerical quantities in neural nets, and for the coding of neural network structures in genetic algorithms. A principal component analysis of natural images yields receptive fields resembling horizontal and vertical edge and bar detectors. The orientation sensitivity of the "bar detector" components is found to match a psychophysical model, suggesting that the brain may make some use of principal components in its visual processing. Experiments are reported on the effects of different input and output codings on the accuracy of neural nets handling numeric data. It is found that simple analogue and interpolation codes are most successful. Experiments on the coding of image data demonstrate the sensitivity of final performance to the internal structure of the net. The interaction between the coding of the target problem and reproduction operators of mutation and recombination in GAs are discussed and illustrated. The possibilities for using GAs to adapt aspects of NNs are considered. The permutation problem, which affects attempts to use GAs both to train net weights and adapt net structures, is illustrated and methods to reduce it suggested. Empirical tests using a simulated net design problem to reduce evaluation times indicate that the permutation problem may not be as severe as has been thought, but suggest the utility of a sorting recombination operator, that matches hidden units according to the number of connections they have in common. A number of experiments using GAs to design network structures are reported, both to specify a net to be trained from random weights, and to prune a pre-trained net. Three different coding methods are tried, and various sorting recombination operators evaluated. The results indicate that appropriate sorting can be beneficial, but the effects are problem-dependent. It is shown that the GA tends to overfit the net to the particular set of test criteria, to the possible detriment of wider generalisation ability. A method of testing the ability of a GA to make progress in the presence of noise, by adding a penalty flag, is described

Monozygotic twins' colour-number association: a case study

A case study of a pair of monozygotic twins, both of whom show a strong and enduring colour-number association, is reported. The origin of the colours, in a jigsaw puzzle, is known. Neither reports conscious photisms typical of synaesthesia, but a Stroop task of naming the colours of digits shows an interference effect with incongruent colours