2,166 research outputs found

    An Interactive Model of Teaching

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    Previous teaching models in the learning theory community have been batch models. That is, in these models the teacher has generated a single set of helpful examples to present to the learner. In this paper we present an interactive model in which the learner has the ability to ask queries as in the query learning model of Angluin [1]. We show that this model is at least as powerful as previous teaching models. We also show that anything learnable with queries, even by a randomized learner, is teachable in our model. In all previous teaching models, all classes shown to be teachable are known to be efficiently learnable. An important concept class that is not known to be learnable is DNF formulas. We demonstrate the power of our approach by providing a determinstic teacher and learner for the class of DNF formulas. The learner makes only equivalence queries and all hypotheses are also DNF formulas

    Learning and Teaching of Boolean and Geometric Classes

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    We consider the concept classes of DNF formulas and unions of discretized, axis-parallel d-dimensional boxes in discretized d-dimensional space with respect to several different learning models. In the model of learning with queries we present an algorithm to learn unions of boxes. We introduce a model of teaching that prevents illicit communication between the teacher and the leaner but that captures the intuitive aspect of teaching: a learner should perform at least as well with a cooperative teacher as with an adversarial teacher. We propose the study of teaching of DNF formulas and unions of boxes in this model. We also propose a study of a teaching model in which the learner may be randomized. It is currently unclear if randomization of the learner allows teaching of classes that are unteachable in the current teaching model

    Computer Vision Based Object Detection and Tracking in Micro Aerial Vehicles

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    ­­­­The ultimate goal of Computer Vision is to instruct a computer to understand and interpret visual signals and images in real time and to instruct a computer to react to the environment around them. In this work, we describe a system that allows a micro aerial vehicle (MAV), equipped with an onboard camera, to detect and track a moving target object. In an alternative implementation, the MAV instead searches the environment for the target object and flies to it. Due to the limited capability of the drone’s integrated processor, image processing is performed by a ground-based computer that also determines the necessary flight corrections and communicates them to the vehicle. The complete system, comprised of the MAV, off-board computer, and software, operates autonomously, a necessary condition for many of the applications for which such systems may be useful

    Noise-Tolerant Parallel Learning of Geometric Concepts

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    We present several efficient parallel algorithms for PAC-learning geometric concepts in a constant-dimensional space. The algorithms are robust even against malicious classification noise of any rate less than 1/2. We first give an efficient noise-tolerant parallel algorithm to PAC-learn the class of geometric concepts defined by a polynomial number of (d-1)-dimensional hyperplanes against an arbitrary distribution where each hyperplane has a slope from a set of known slopes. We then describe how boosting techniques can be used so that our algorithms\u27 dependence on {GREEK LETTER} and {DELTA} does not depend on d. Next we give an efficient noise-tolerant parallel algorithm to PAC-learn the class of geometric concepts defined by a polynomial number of (d-1)-dimensional hyperplanes (of unrestricted slopes) against a uniform distribution. We then show how to extend our algorithm to learn this class against any (unknown) product distribution. Next we defined a complexity measure of any set S of (d-1)-dimensional surfaces that we call the variant of S and prove that the class of geometric concepts defined by surfaces of polynomial variant can be efficienty learned in parallel under a product distribution (even under malicious classification noise). Furthermore, we show that the VC-dimension of the class of geometric concepts defined by a set of surfaces S of variant v is at least v. Finally, we give an efficient, parallel, noise-tolerant algorithm to PAC-learn any geometric concept defined by a set S of (d-1)-dimensional surfaces of polynomial area under a uniform distribution

    Book Reviews

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    Internet interventions for mental health in university students:A systematic review and meta-analysis

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    OBJECTIVES: Mental health disorders are highly prevalent among university students. Universities could be an optimal setting to provide evidence-based care through the Internet. As part of the World Mental Health International College Student initiative, this systematic review and meta-analysis synthesizes data on the efficacy of Internet-based interventions for university students' mental health. METHOD: A systematic literature search of bibliographical databases (CENTRAL, MEDLINE, and PsycINFO) for randomized trials examining psychological interventions for the mental health (depression, anxiety, stress, sleep problems, and eating disorder symptoms), well-being, and functioning of university students was performed through April 30, 2018. RESULTS: Forty-eight studies were included. Twenty-three studies (48%) were rated to have low risk of bias. Small intervention effects were found on depression (g = 0.18, 95% confidence interval [CI; 0.08, 0.27]), anxiety (g = 0.27, 95% CI [0.13, 0.40]), and stress (g = 0.20, 95% CI [0.02, 0.38]). Moderate effects were found on eating disorder symptoms (g = 0.52, 95% CI [0.22-0.83]) and role functioning (g = 0.41, 95% CI [0.26, 0.56]). Effects on well-being were non-significant (g = 0.15, 95% CI [-0.20, 0.50]). Heterogeneity was moderate to substantial in many analyses. After adjusting for publication bias, effects on anxiety were not significant anymore. DISCUSSION: Internet interventions for university students' mental health can have significant small-to-moderate effects on a range of conditions. However, more research is needed to determine student subsets for which Internet-based interventions are most effective and to explore ways to increase treatment effectiveness. © 2018 John Wiley & Sons, Ltd. KEYWORDS: Internet; college; mental disorders; meta-analysis; psychotherap

    Long-term planning and its role as a tool of fiscal security of the economy

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    Актуальность исследования определяется тем, что обеспечение бюджетно-финансовой безопасности в России связано с проведением исполнительными органами государственной власти бюджетно-финансового планирования, основанного на принципах законности, плановости и открытости, прописанных в Бюджетном кодексе РФ. Все это рождает острую необходимость принятия базового документа (Долгосрочной бюджетной стратегии). Цель работы: провести анализ бюджетно-финансового планирования в его историческом, межстрановом и правовом аспектах, дать характеристику современного состояния бюджетно-финансового планирования в России. Методы исследования: моделирование, обобщение зарубежного опыта использования долгосрочного планирования, сопоставление и контент-анализ, который позволил выявить принципы долгосрочного планирования в бюджетной сфере, а также острую необходимость принятия Долгосрочной бюджетной стратегии на современном этапе в России. Результаты. Проведенное исследование отражает генезис бюджетного планирования в России в 1917-2017 гг. Анализ применения такого планирования в развитых странах (США, Германия, Великобритания, Франция и др.) определил основные принципы, которые могут быть заложены в основу Долгосрочной бюджетной стратегии в России на федеральном и региональном уровнях. Как основной базовый документ бюджетно-финансового планирования текущего периода утвержденная Долгосрочная бюджетная стратегия позволит предопределить результаты долгосрочного развития и обеспечить достаточный уровень экономической безопасности бюджетно- финансовой сферы.The relevance of this research is determined by the fact that ensuring fiscal security in Russia is connected with the Executive bodies of state power, budget and financial planning based on the principles of legality, planning and openness spelled out in the Budget code of the Russian Federation. All this creates an urgent need of adoption of the core document (Long-term budget strategy). The aim of the work is to analyze the budget and financial planning in its historical, interstate and legal aspects, State of fiscal planning in Russia. Research methods: modeling, generalization of foreign experience in using long-term planning. Comparison and content analysis, which allowed revealing the principles of long-term planning in the budgetary sphere and urgent need to adopt a Long-term budget strategy at the present stage in Russia. Results. The study reflects the Genesis of budget planning in Russia in 1917-2017. Analysis of application of such planning in developed countries (USA, Germany, UK, France, etc.) helped identify basic principles that can be the base of Long-term budget strategy in Russia at Federal and regional levels. The approved Long-term budget strategy, as the base document for budget and financial planning of the current period, will enable to predetermine the outcome of long-term development and to ensure a sufficient level of economic security fiscal sphere

    Serum phosphatidylinositol as a biomarker for bipolar disorder liability

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    Objectives Individuals with bipolar disorder (BPD) exhibit alterations in their phospholipid levels. It is unclear whether these alterations are a secondary consequence of illness state, or if phospholipids and illness risk overlap genetically. If the latter were true, then phospholipids might provide key insights into the pathophysiology of the illness. Therefore, we rank-ordered phospholipid classes by their genetic overlap with BPD risk in order to establish which class might be most informative in terms of increasing our understanding of illness pathophysiology. Methods Analyses were conducted in a sample of 558 individuals, unselected for BPD, from 38 extended pedigrees (average family size=14.79, range=2–82). We calculated a coefficient of relatedness for all family members of nine individuals with BPD in the sample (N=185); this coefficient was set to be zero in unrelated individuals (N=373). Then, under an endophenotype ranking value (ERV) approach, this scalar index was tested against 13 serum-based phospholipid concentrations in order to rank-order lipid classes by their respective overlap with BPD risk. Results The phosphatidylinositol class was significantly heritable (h2=0.26, P=6.71 × 10−05). It was the top-ranked class, and was significantly associated with BPD risk after correction for multiple testing (β=−1.18, P=2.10 × 10−03, ERV=0.49). Conclusions We identified a peripheral biomarker, serum-based phosphatidylinositol, which exhibits a significant association with BPD risk. Therefore, given that phosphatidylinositol and BPD risk share partially common etiology, it seems that this lipid class warrants further investigation, not only in terms of treatment, but also as a promising diagnostic and risk marker
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