A first-principles study of the vibrational modes of PbTiO3 in the ferroelectric tetragonal phase has been performed at all the main symmetry points of the Brillouin zone ~BZ!. The calculations use the local-density approximation and ultrasoft pseudopotentials with a plane-wave basis, and reproduce well the available experimental information on the modes at the G point, including the LO-TO spli...

Résumé. La reconnaissance de l'écriture arabe manuscrite est un domaine de recherche relativement récent et qui a connu ces dernières années des progrès remarquables. Il présente un intérêt indéniable dans l’accomplissement de tâches considérées fastidieuses dans certains domaines comme le tri postal, la lecture de chèques bancaires, la lecture des bordereaux, etc. Ce papier présente la concept...

Carl Gustav Hempel 's (19051997) classic account of explanation is widely known as the "cover ing-law model. " It includ es two species : the Deductive-Nomological Expla nation and the Probabilistic-Statist ical Explanation . Since its introduction in the semi nal pape r co-authored by Hempel and Paul Oppenheim (1948), the model has been intense ly debated and criticized in the philosophy of sc...

In 2011, the publicly held debt-to-GDP ratio in the United States reached 68% and is expected to continue rising. Many proposals to curb the government de…cit and the resulting debt are being discussed. In this paper, we use the standard neoclassical growth model to examine the future path of output, budget de…cits, and debt in the U.S. economy under di¤erent tax policies. While this framework ...

This paper presents a SRGM (software reliability growth model) with both change-point and environmental function based on NHPP (non-homogeneous Poisson process). Although a few research projects have been devoted to the change-point problems of SRGMs, consideration of the variation of environmental factors in the existing models during testing time is limited. The proposed model is one of a few...

purpose: this survey examines the view points of the librarians in the central libraries of the state universities of tehran on the necessity of continuing education (ce) courses. methodology: a questionnaire survey was conducted (76.7% response rate) to assess the requirement of continuing education (ce) courses. findings: the results showed that about 98% of the librarians believe that it nec...

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RÉSUMÉ. Cet article présente une approche sociale pour la recherche d’information dans les microblogs intégrant diverses sources d’évidence au sein d’un réseau bayésien. Notre contribution consiste à étendre la notion classique de pertinence, basée sur la similarité textuelle, par de nouveaux facteurs tels que l’importance sociale des blogueurs et la magnitude temporelle des microblogs. Dans ce...