131,550 research outputs found
Correction to “Automatic Block-Length Selection for the Dependent Bootstrap” by D. Politis and H. White
No full textA correction on the optimal block size algorithms of Politis and White (2004) is given following a correction of Lahiri's (Lahiri 1999) theoretical results by Nordman (2008).Block bootstrap, Block size, Circular bootstrap, Stationary bootstrap,
Corrigendum to ‘Subsampling Inference for the Mean of Heavy‐Tailed Long‐Memory Time Series’ by A. Jach, T. S. McElroy and D. N. Politis
No full textA corrected statement and proof of Theorem 4 of Jach, McElroy, and Politis (2012) is provided.Non peer reviewe
Ghawr as-Safi Survey and Excavations 2006-2007
No full textKonstantinos D. Politis, Margaret O'Hea, Georgios A. Papaioanno
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Extrapolation de distribution de sous-échantillonnage dans les cas I. I. D. et "fortement mélangeants"
No full textSérie des documents de travail du CORELA et de HEDM ; 9604 Diffusion du document : INRA Station d'Economie et Sociologie rurales, 65 boulevard de Brandebourg, 94205 Ivry Cedex (FRA) Cote de localisation : PAR. BRT. 1996/P0663 96-04Dans les travaux de D. N. Politis et J. P. Romano, une méthodologie générale de sous-échantillonnage a été proposée pour la construction de régions de confiance asymptotique pour un paramètre thêta thêta (P) inconnu sous des conditions minimales. Néanmoins, dans quelques cas spécifiques, par exemple le cas i. i. d., il a été remarqué que les estimateurs de distribution de sous-échantillonnage étaient sous-efficaces par rapport à des estimateurs alternatifs tels que le bootstrap et/ou la distribution normale asymptotique (avec variance estimée). Les auteurs évaluent jusqu'à quel point des distributions de sous-échantillonnage peuvent être améliorées par la technique d'extrapolation, tout en assurant le maintien de la propriété de robustesse et de consistance de la distribution, même dans les cas non-réguliers. Les cas d'observations i. i. d. et/ou fortement mélangeants sont étudiés
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Extrapolation de distribution de sous-échantillonnage dans les cas I. I. D. et "fortement mélangeants"
No full textSérie des documents de travail du CORELA et de HEDM ; 9604 Diffusion du document : INRA Station d'Economie et Sociologie rurales, 65 boulevard de Brandebourg, 94205 Ivry Cedex (FRA) Cote de localisation : PAR. BRT. 1996/P0663 96-04Dans les travaux de D. N. Politis et J. P. Romano, une méthodologie générale de sous-échantillonnage a été proposée pour la construction de régions de confiance asymptotique pour un paramètre thêta thêta (P) inconnu sous des conditions minimales. Néanmoins, dans quelques cas spécifiques, par exemple le cas i. i. d., il a été remarqué que les estimateurs de distribution de sous-échantillonnage étaient sous-efficaces par rapport à des estimateurs alternatifs tels que le bootstrap et/ou la distribution normale asymptotique (avec variance estimée). Les auteurs évaluent jusqu'à quel point des distributions de sous-échantillonnage peuvent être améliorées par la technique d'extrapolation, tout en assurant le maintien de la propriété de robustesse et de consistance de la distribution, même dans les cas non-réguliers. Les cas d'observations i. i. d. et/ou fortement mélangeants sont étudiés
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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