61 research outputs found

    GP-SUM. Gaussian Processes Filtering of non-Gaussian Beliefs

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    This work studies the problem of stochastic dynamic filtering and state propagation with complex beliefs. The main contribution is GP-SUM, a filtering algorithm tailored to dynamic systems and observation models expressed as Gaussian Processes (GP), and to states represented as a weighted sum of Gaussians. The key attribute of GP-SUM is that it does not rely on linearizations of the dynamic or observation models, or on unimodal Gaussian approximations of the belief, hence enables tracking complex state distributions. The algorithm can be seen as a combination of a sampling-based filter with a probabilistic Bayes filter. On the one hand, GP-SUM operates by sampling the state distribution and propagating each sample through the dynamic system and observation models. On the other hand, it achieves effective sampling and accurate probabilistic propagation by relying on the GP form of the system, and the sum-of-Gaussian form of the belief. We show that GP-SUM outperforms several GP-Bayes and Particle Filters on a standard benchmark. We also demonstrate its use in a pushing task, predicting with experimental accuracy the naturally occurring non-Gaussian distributions.Comment: WAFR 2018, 16 pages, 7 figure

    Prenatal and Perinatal Risk Factors for Autism in China

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    We conducted a case–control study using 190 Han children with and without autism to investigate prenatal and perinatal risk factors for autism in China. Cases were recruited through public special education schools and controls from regular public schools in the same region (Tianjin), with frequency matching on sex and birth year. Unadjusted analyses identified seven prenatal and seven perinatal risk factors significantly associated with autism. In the adjusted analysis, nine risk factors showed significant association with autism: maternal second-hand smoke exposure, maternal chronic or acute medical conditions unrelated to pregnancy, maternal unhappy emotional state, gestational complications, edema, abnormal gestational age (<35 or >42 weeks), nuchal cord, gravidity >1, and advanced paternal age at delivery (>30 year-old)

    The SPECTRA Collaboration OMERACT Special Interest Group: Current Research and Future Directions

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    Objective High-resolution peripheral quantitative computed tomography (HR-pQCT) has the potential to improve radiographic progression determination in clinical trials and longitudinal observational studies. The goal of this work was to describe the current state of research presented at Outcome Measures in Rheumatology (OMERACT) 2016 and ensuing future directions outlined during discussion among attendees. Methods At OMERACT 2016, SPECTRA (Study grouP for xtrEme-Computed Tomography in Rheumatoid Arthritis) introduced efforts to (1) validate the HR-pQCT according to OMERACT guidelines, focusing on rheumatoid arthritis (RA), and (2) find alternatives for automated joint space width (JSW) analysis. The Special Interest Group (SIG) was presented to patient research partners, physicians/researchers, and SIG leaders followed by a 40-min discussion on future directions. Results A consensus definition for RA erosion using HR-pQCT was demonstrated through a systematic literature review and a Delphi exercise. Histopathology and perfusion studies were presented that analyzed the true characteristics of cortical breaks in HR-pQCT images, and to provide criterion validity. Results indicate that readers were able to discriminate between erosion and small vascular channels. Moderate reliability (ICC 0.206–0.871) of direct erosion size measures was shown, which improved (> 0.9) only when experienced readers were considered. Quantification of erosion size was presented for scoring, direct measurement, and volumetric approaches, as well as a reliability exercise for direct measurement. Three methods for JSW measurement were compared, all indicating excellent reproducibility with differences at the extremes (i.e., near-zero and joint edge thickness). Conclusion Initial reports on HR-pQCT are promising; however, to consider its use in clinical trials and longitudinal observational studies, it is imperative to assess the responsiveness of erosion measurement quantification

    Detecting Latin-based Medical Terminology in Croatian Texts.

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    No matter what the main language of texts in the medical domain is, there is always an evidence of the usage of Latin-derived words and formative elements in terminology development. Generally speaking, this usage presents language-specific morpho-semantic behaviors in forming both technical-scientific and common-usage words. Nevertheless, this usage of Latin in Croatian medical texts does not seem consistent due to the fact that different mechanisms of word formation may be applied to the same term. In our pursuit to map all the different occurrences of the same concept to only one, we propose a model designed within NooJ and based on dictionaries and morphological grammars. Starting from the manual detection of nouns and their variations, we recognize some word formation mechanisms and develop grammars suitable to recognize Latinisms and Croatinized Latin medical terminology

    Global Populism Database, v1

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    Global Populism Database measures the level of populist discourse in the speeches of 215 chief executives (presidents and prime ministers) from 66 countries across all continents. The dataset covers 279 government terms and includes more than 1,000 speeches, mostly between 2000 and 2018. Each speech is coded manually by one or two coders using the "holistic grading" (Hawkins 2009) technique

    Negation of Croatian Nouns

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    The purpose of this paper is to describe a morphological grammar for recog-nizing negation of a noun and annotating its polarity accordingly. Not all nouns can be negated on the morphological level. For example, nouns like ‘activity’ and ‘knowledge’ (aktivnost, znanje) can have negatives (neak-tivnost, neznanje respectfully), but the same is not the case for nouns such as ‘battle’ or ‘table’ (bitka or stol). The most common and frequent Croatian prefix for negation of nouns is ‘ne-’ although several more are used either of Slavic (‘be-‘, ‘bez-‘) or Latin origin (‘anti-‘, ‘dis-‘). In some cases, negated nouns actually denote positive concepts, whereas their non-negated counter-parts are used for expressing concepts with negative connotations. For this purpose, all the nouns in NooJ dictionary, that may have nouns in both po-larities, are provided with [Polarity=pos] or [Polarity=neg] marker. This in-formation is used in the grammar to switch the polarity of the opposite noun after the insertion of a negative prefix. The grammar is tested on different types of corpora and results are discussed
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