Learning Function-Free Horn Expressions

The problem of learning universally quantified function free first order Horn expressions is studied. Several models of learning from equivalence and membership queries are considered, including the model where interpretations are examples (Learning from Interpretations), the model where clauses are examples (Learning from Entailment), models where extensional or intentional background knowledge is given to the learner (as done in Inductive Logic Programming), and the model where the reasoning performance of the learner rather than identification is of interest (Learning to Reason). We present learning algorithms for all these tasks for the class of universally quantified function free Horn expressions. The algorithms are polynomial in the number of predicate symbols in the language and the number of clauses in the target Horn expression but exponential in the arity of predicates and the number of universally quantified variables. We also provide lower bounds for these tasks by way of characterising the VC-dimension of this class of expressions. The exponential dependence on the number of variables is the main gap between the lower and upper bounds.     

Imbalance in Sirt1 Alternative Splicing in Response to Chronic Stress during the Adolescence Period in Female Mice

Stressful unpredictable life events have been implicated in numerous diseases. It is now becoming clear that some life periods are more vulnerable than others. As adolescence is a sensitive period in brain development, the long-term effects of stress during this period could be significant. We investigated the long-term effects of exposure to unpredictable chronic mild stress in adolescent mice on alternative splicing of Sirtuin 1. One-month-old mice were exposed to 4 weeks of UCMS and examined for anxiety and cognition at the age of 2, 4 and 6 months. We found a rise in anxious behavior immediately after the exposure to stress. Notably, there was a long-term impairment of performance in cognitive tasks and an imbalance in Sirtuin 1 and TrkB receptor alternative splicing in the stress-exposed mice compared with controls. To conclude, our results show that exposure to unpredictable chronic mild stress during adolescence affects cognition in adulthood. Understanding pathways affiliated with stress may help minimize the long-term emotional effects of an unpredictable, stressful event.     

Template-Based Volume Viewing

We present an efficient three-phase algorithm for volume viewing that is based on exploiting coherency between rays in parallel projection. The algorithm starts by building a ray-template and determining a special plane for projection - the base-plane. Parallel rays are cast into the volume from within the projected region of the volume on the base-plane, by repeating the sequence of steps specified in the ray-template. We carefully choose the type of line to be employed and the way the template is being placed on the base-plane in order to assure uniform sampling of the volume by the discrete rays. We conclude by describing an optimized software implementation of our algorithm and reporting its performance.     

Building a virtual environment for endoscopic sinus surgery simulation

Advanced display technologies have made the virtual exploration of relatively complex models feasible in many applications. Unfortunately, only a few human interfaces allow natural interaction with the environment. Moreover, in surgical applications, such realistic interaction requires real-time rendering of volumetric data—placing an overwhelming performance burden on the system. We report on our advances towards developing a virtual reality system that provides intuitive interaction with complex volume data by employing real-time realistic volume rendering and convincing forece feedback (haptic) sensations. We describe our methods for real-time volume rendering, model deformation, interaction, and the haptic devices, and demonstrate the utilization of this system in the real-world application of Endoscopic Sinus Surgery (ESS) simulation.     

Suicide and malpractice: Expert testimony and the standard of care.

Investigated the effects of both professional discipline and retrospective knowledge of suicidal outcome on evaluations of treatment by mailing questionnaires to 156 psychiatrists, psychologists, social workers, and suicidologists containing 1 of 2 versions of a hypothetical case (with and without a suicide outcome). Results indicate that neither knowledge of the suicidal outcome nor expertise in suicidology affected judgments of treatment; professions, however, did vary both in the level of care they accepted as standard and in their willingness to endorse malpractice suits. These differences are discussed in terms of implications for establishing standards for and maximizing the quality of care given to suicidal patients. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual analysis of quality-related manufacturing data using fractal geometry

Improving manufacturing quality is an important challenge in various industrial settings. Data mining methods mostly approach this challenge by examining the effect of operation settings on product quality. We analyze the impact of operational sequences on product quality. For this purpose, we propose a novel method for visual analysis and classification of operational sequences. The suggested framework is based on an Iterated Function System (IFS), for producing a fractal representation of manufacturing processes. We demonstrate our method with a software application for visual analysis of quality-related data. The proposed method offers production engineers an effective tool for visual detection of operational sequence patterns influencing product quality, and requires no understanding of mathematical or statistical algorithms. Moreover, it enables to detect faulty operational sequence patterns of any length, without predefining the sequence pattern length. It also enables to visually distinguish between different faulty operational sequence patterns in cases of recurring operations within a production route. Our proposed method provides another significant added value by enabling the visual detection of rare and missing operational sequences per product quality measure. We demonstrate cases in which previous methods fail to provide these capabilities.     

Inter-group differences in road-traffic crash involvement

This paper assesses group differences in severe and fatal road-traffic accidents by using a unique database that merges road-traffic records with the Israeli census data. The database traces, over a period of 9 years, a group of drivers that comprises 20% of the Israeli population and explores the probability of their being involved in an accident. This unique database enables the investigation of drivers’ socioeconomic and demographic characteristics, while controlling for a variety of variables, such as estimated daily distance traveled and license type. Testing a previously published theoretical paper on the social bases of accidents, the findings expose significant group differences in estimated probabilities of being involved in severe and fatal accidents. For example, estimated probabilities of accident involvement are higher for males than for females, for non-Jewish drivers than for Jewish, and for drivers whose origins are in Africa and Asia than in America and Europe. Furthermore, the higher one's education and socioeconomic status, the lower is the probability of accident-involvement. The implications of the findings for developing road-safety programs and suggestions for future research are discussed.