Learning Tuple Probabilities in Probabilistic Databases

Learning the parameters of complex probabilistic-relational models from labeled training data is a standard technique in machine learning, which has been intensively studied in the subfield of Statistical Relational Learning (SRL), but---so far---this is still an under-investigated topic in the context of Probabilistic Databases (PDBs). In this paper, we focus on learning the probability values of base tuples in a PDB from query answers, the latter of which are represented as labeled lineage formulas. Specifically, we consider labels in the form of pairs, each consisting of a Boolean lineage formula and a marginal probability that comes attached to the corresponding query answer. The resulting learning problem can be viewed as the inverse problem to confidence computations in PDBs: given a set of labeled query answers, learn the probability values of the base tuples, such that the marginal probabilities of the query answers again yield in the assigned probability labels. We analyze the learning problem from a theoretical perspective, devise two optimization-based objectives, and provide an efficient algorithm (based on Stochastic Gradient Descent) for solving these objectives. Finally, we conclude this work by an experimental evaluation on three real-world and one synthetic dataset, while competing with various techniques from SRL, reasoning in information extraction, and optimization

Heads or Tails? Modified Ceramic Gaming Pieces from Colonial California

Modified ceramic disks have been recovered from historic-era sites across the Americas. Small unperforated disks are commonly interpreted as gaming pieces and larger perforated disks are often classified as spindle whorls. Here, we examine these interpretations in light of collections from three colonial-era sites in central California: Mission San Antonio de Padua, Mission San José, and the Rancho San Andrés Castro Adobe. We argue that the small unperforated disks from our study sites were two-sided dice. These gaming pieces facilitated the social cohesion of Native people living in the large, multiethnic Indigenous communities that formed around Spanish colonial missions and later Mexican-era ranchos

Learning relational event models from video

Event models obtained automatically from video can be used in applications ranging from abnormal event detection to content based video retrieval. When multiple agents are involved in the events, characterizing events naturally suggests encoding interactions as relations. Learning event models from this kind of relational spatio-temporal data using relational learning techniques such as Inductive Logic Programming (ILP) hold promise, but have not been successfully applied to very large datasets which result from video data. In this paper, we present a novel framework REMIND (Relational Event Model INDuction) for supervised relational learning of event models from large video datasets using ILP. Efficiency is achieved through the learning from interpretations setting and using a typing system that exploits the type hierarchy of objects in a domain. The use of types also helps prevent over generalization. Furthermore, we also present a type-refining operator and prove that it is optimal. The learned models can be used for recognizing events from previously unseen videos. We also present an extension to the framework by integrating an abduction step that improves the learning performance when there is noise in the input data. The experimental results on several hours of video data from two challenging real world domains (an airport domain and a physical action verbs domain) suggest that the techniques are suitable to real world scenarios

Molecular Beams

Contains reports on three research projects.Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DA 28-043-AMC-02536(E

Vacuum Polarization and the Electric Charge of the Positron

We show that higher-order vacuum polarization would contribute a measureable net charge to atoms, if the charges of electrons and positrons do not balance precisely. We obtain the limit $|Q_e+Q_{\bar e}| < 10^{-18} e$ for the sum of the charges of electron and positron. This also constitutes a new bound on certain violations of PCT invariance.Comment: 9 pages, 1 figure attached as PostScript file, DUKE-TH-92-38. Revised versio

Electric charge quantization without anomalies?

In gauge theories like the standard model, the electric charges of the fermions can be heavily constrained from the classical structure of the theory and from the cancellation of anomalies. We argue that the anomaly conditions are not quite as well motivated as the classical constraints, since it is possible that new fermions could exist which cancel potential anomalies. For this reason we examine the classically allowed electric charges of the known fermions and we point out that the electric charge of the tau neutrino is classically allowed to be non-zero. The experimental bound on the electric charge of the tau neutrino is many orders of magnitude weaker than for any other known neutrino. We discuss possible modifications of the minimal standard model such that electric charge is quantized classically.Comment: 10 McGill/93-3

Comparison of the tetrahedron method to smearing methods for the electronic density of states

The electronic density of states (DOS) highlights fundamental properties of materials that oftentimes dictate their properties, such as the band gap and Van Hove singularities. In this short note, we discuss how sharp features of the density of states can be obscured by smearing methods (such as the Gaussian and Fermi smearing methods) when calculating the DOS. While the common approach to reach a "converged" density of states of a material is to increase the discrete k-point mesh density, we show that the DOS calculated by smearing methods can appear to converge but not to the correct DOS. Employing the tetrahedron method for Brillouin zone integration resolves key features of the density of states far better than smearing methods

Tractable Fragments of Temporal Sequences of Topological Information

In this paper, we focus on qualitative temporal sequences of topological information. We firstly consider the context of topological temporal sequences of length greater than 3 describing the evolution of regions at consecutive time points. We show that there is no Cartesian subclass containing all the basic relations and the universal relation for which the algebraic closure decides satisfiability. However, we identify some tractable subclasses, by giving up the relations containing the non-tangential proper part relation and not containing the tangential proper part relation. We then formalize an alternative semantics for temporal sequences. We place ourselves in the context of the topological temporal sequences describing the evolution of regions on a partition of time (i.e. an alternation of instants and intervals). In this context, we identify large tractable fragments

Dental and physical therapy faculty collaborate in assessing and educating dental students on musculoskeletal disorders

Introduction: Research shows 54% to 93% of practicing dentists suffer from musculoskeletal disorders (MSDs), with many developing afflictions early in their careers. Studies also show that dental students are developing MSDs early in their professional education. Objective: The research goal was to quantify the prevalence, anatomical location and initial onset of MSDs among first-year dental students. The study also assessed the students’ self-reported opinion as to whether there were enough educational touchpoints to improve their ergonomics in daily activities. Methods: At the conclusion of a 9-month preclinical restorative course, that included 2 lectures on MSDs, ergonomics, and postural cueing sessions, a dental and physical therapy faculty member administered a survey to 143 first-year dental students. This survey included questions about the history and presentation of the students’ MSD symptoms and their opinion on the relative value of the educational interventions. Results: There was a 96.5% response rate to the survey with 87.8% of students reporting mild to moderate pain. The cervical spine (41.7%) and hands (42.4%) were the most common areas afflicted. 55.4% reported pain commencing 1 month after starting in the simulation clinic. Over 60.9% of students “agreed” or “somewhat agreed” that the 2 sessions of hands-on ergonomic educational interventions resulted in improved biomechanics and students requested additional educational resources. Conclusion: Dental students are developing MSDs as soon as 1 month after commencing dental school. Dental education should include ongoing ergonomic training throughout the curriculum to help students prevent MSDs