A New Analysis for Support Performance with Block Generalized Orthogonal Matching Pursuit

For recovering block-sparse signals with unknown block structures using compressive sensing, a block orthogonal matching pursuit- (BOMP-) like block generalized orthogonal matching pursuit (BgOMP) algorithm has been proposed recently. This paper focuses on support conditions of recovery of any K -sparse block signals incorporating BgOMP under the framework of restricted isometry property (RIP). The proposed support conditions guarantee that BgOMP can achieve accurate recovery block-sparse signals within k iterations.

Postprint BuckfieldSinclairGlautier (2020) Slow associative learning in alcohol dependence and the Alcohol Cue Exposure Treatment Paradox

The published version is available at: https://onlinelibrary.wiley.com/doi/epdf/10.1111/add.15210 AimsTo examine two explanations for the observation that cue-exposure treatment has not been clearly effective in the treatment of alcohol dependence: do alcohol dependent individuals have either 1) slower extinction and/or 2) greater contextual specificity of extinction than non-dependent individuals? DesignIn two exploratory laboratory experiments we used mixed factorial designs with two-group between-subjects factors and within-subjects factors corresponding to performance in different parts of a computer-based learning task.SettingUniversity of Southampton psychology research laboratories and two addiction treatment services in the city of Southampton, UK.ParticipantsExperiment 1: Seventy-four (54 female) undergraduates from the University of Southampton (age M=20.4 years). Experiment 2: One-hundred and two (40 female) participants from the University of Southampton, the local community, and from two Southampton alcohol treatment services (age M=41.3 years). MeasurementsThe Alcohol Use Disorders Identification Test, a 1-week time-line follow-back alcohol consumption questionnaire, the Barratt Impulsiveness Scale (11th Ed), and a computerised learning task. Experiment 2 additionally used the 44-item Big Five Inventory, a drug use history checklist, and the Hospital Anxiety and Depression Scale. FindingsExperiment 1: light and heavy drinkers did not differ significantly in extinction (extinction block x drinking status interaction, p=.761, η_p^2=.005, 95% confidence interval (0,.028)) or on contextual control of extinction (recovery block x drinking status interaction, p=.514, η_p^2=.009, 95% confidence interval (0,.084)). Experiment 2: slower extinction in abstinent alcohol dependent participants compared with light drinkers (extinction block x drinking status interaction, p=.023, η_p^2=.031, 95% confidence interval (0,.069)) but no significant difference on contextual control of extinction (recovery block x drinking status interaction, p=.069, η_p^2=.033, 95% confidence interval (0,.125)). ConclusionAbstinent alcohol dependent people may have slower extinction learning for alcohol-related cues, than non-dependent light drinkers.

A Novel Image Tamper Detection and Self-Recovery Algorithm Based on Watermarking and Chaotic System

With the development of image editing software techniques, the content integrity and authenticity of original digital images become more and more important in digital content security. A novel image tampering detection and recovery algorithm based on digital watermarking technology and a chaotic system is proposed, and it can effectively locate the tampering region and achieve the approximate recovery of the original image by using the hidden information. The pseudo-random cyclic chain is realized by the chaotic system to construct the mapping relationship between the image subblocks. It can effectively guarantee the randomness of the positional relationship between the hidden information and the original image block for the better ergodicity of the pseudo-random chain. The recovery value optimization algorithm can represent image information better. In addition to the traditional Level-1 recovery, a weight adaptive algorithm is designed to distinguish the original block from the primary recovery block, allowing 3 × 3 neighbor block recovery to achieve better results. The experimental results show that the hierarchical tamper detection algorithm makes tamper detection have higher precision. When facing collage attacks and large general tampering, it will have higher recovery image quality and better resistance performance.

The urge to blink in Tourette syndrome

Functional neuroimaging studies have attempted to explore brain activity that occurs with tic occurrence in subjects with Tourette syndrome (TS). However, they are limited by the difficulty of disambiguating brain activity required to perform a tic, or activity caused by the tic, from brain activity that generates a tic. Inhibiting the urge to tic is important to patients’ experience of tics and we hypothesize that inhibition of a compelling motor response to a natural urge will differ in TS subjects compared to controls. This study examines the urge to blink, which shares many similarities to premonitory urges to tic. Previous neuroimaging studies with the same hypothesis have used a one-size-fits-all approach to extract brain signal putatively linked to the urge to blink. We aimed to create a subject-specific and blink-timing-specific pathophysiological model, derived from out-of-scanner blink suppression trials, to eventually better interpret blink suppression fMRI data. Eye closure and continuously self-reported discomfort were reported during five blink suppression trials in 30 adult volunteers, 15 with a chronic tic disorder. For each subject, data from four of the trials were used with an empirical mathematical model to predict discomfort from eye closure observed during the remaining trial. The blink timing model of discomfort during blink suppression predicted observed discomfort much better than previously applied models. However, so did a model that simply reflected the mean time-discomfort curves from each subject’s other trials. The TS group blinked more than twice as often during the blink suppression block, and reported higher baseline discomfort, smaller excursion from baseline to peak discomfort during the blink suppression block, and slower return of discomfort to baseline during the recovery block. Combining this approach with observed eye closure during fMRI blink suppression trials should therefore extract brain signal more tightly linked to the urge to blink.