Academic literature on the topic 'Statistical inversions'
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Journal articles on the topic "Statistical inversions"
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Nygård, Tiina, Teresa Valkonen, and Timo Vihma. "Antarctic Low-Tropospheric Humidity Inversions: 10-Yr Climatology." Journal of Climate 26, no. 14 (2013): 5205–19. http://dx.doi.org/10.1175/jcli-d-12-00446.1.
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Abstract Humidity inversions are nearly permanently present in the coastal Antarctic atmosphere. This is shown based on an investigation of statistical characteristics of humidity inversions at 11 Antarctic coastal stations using radiosonde data from the Integrated Global Radiosonde Archive (IGRA) from 2000 to 2009. The humidity inversion occurrence was highest in winter and spring, and high atmospheric pressure and cloud-free conditions generally increased the occurrence. A typical humidity inversion was less than 200 m deep and 0.2 g kg−1 strong, and a typical humidity profile contained several separate inversion layers. The inversion base height had notable seasonal variations, but generally the humidity inversions were located at higher altitudes than temperature inversions. Roughly half of the humidity inversions were associated with temperature inversions, especially near the surface, and humidity and temperature inversion strengths as well as depths correlated at several stations. On the other hand, approximately 60% of the humidity inversions were accompanied by horizontal advection of water vapor increasing with height, which is also a probable factor supporting humidity inversions. The spatial variability of humidity inversions was linked to the topography and the water vapor content of the air. Compared to previous results for the Arctic, the most striking differences in humidity inversions in the Antarctic were a much higher frequency of occurrence in summer, at least under clear skies, and a reverse seasonal cycle of the inversion height. The results can be used as a baseline for validation of weather prediction and climate models and for studies addressing changes in atmospheric moisture budget in the Antarctic.
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Cáceres, Mario, Antonio Barbadilla, and Alfredo Ruiz. "Recombination Rate Predicts Inversion Size in Diptera." Genetics 153, no. 1 (1999): 251–59. http://dx.doi.org/10.1093/genetics/153.1.251.
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Abstract Most species of the Drosophila genus and other Diptera are polymorphic for paracentric inversions. A common observation is that successful inversions are of intermediate size. We test here the hypothesis that the selected property is the recombination length of inversions, not their physical length. If so, physical length of successful inversions should be negatively correlated with recombination rate across species. This prediction was tested by a comprehensive statistical analysis of inversion size and recombination map length in 12 Diptera species for which appropriate data are available. We found that (1) there is a wide variation in recombination map length among species; (2) physical length of successful inversions varies greatly among species and is inversely correlated with the species recombination map length; and (3) neither the among-species variation in inversion length nor the correlation are observed in unsuccessful inversions. The clear differences between successful and unsuccessful inversions point to natural selection as the most likely explanation for our results. Presumably the selective advantage of an inversion increases with its length, but so does its detrimental effect on fertility due to double crossovers. Our analysis provides the strongest and most extensive evidence in favor of the notion that the adaptive value of inversions stems from their effect on recombination.
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Theune, Ulrich, Ingrid Østgård Jensås, and Jo Eidsvik. "Analysis of prior models for a blocky inversion of seismic AVA data." GEOPHYSICS 75, no. 3 (2010): C25—C35. http://dx.doi.org/10.1190/1.3427538.
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Resolving thinner layers and focusing layer boundaries better in inverted seismic sections are important challenges in exploration and production seismology to better identify a potential drilling target. Many seismic inversion methods are based on a least-squares optimization approach that can intrinsically lead to unfocused transitions between adjacent layers. A Bayesian seismic amplitude variation with angle (AVA) inversion algorithm forms sharper boundaries between layers when enforcing sparseness in the vertical gradients of the inversion results. The underlying principle is similar to high-resolution processing algorithms and has been adapted from digital-image-sharpening algorithms. We have investigated the Cauchy and Laplace statistical distributions for their potential to improve contrasts betweenlayers. An inversion algorithm is derived statistically from Bayes’ theorem and results in a nonlinear problem that requires an iterative solution approach. Bayesian inversions require knowledge of certain statistical properties of the model we want to invert for. The blocky inversion method requires an additional parameter besides the usual properties for a multivariate covariance matrix, which we can estimate from borehole data. Tests on synthetic and field data show that the blocky inversion algorithm can detect and enhance layer boundaries in seismic inversions by effectively suppressing side lobes. The analysis of the synthetic data suggests that the Laplace constraint performs more reliably, whereas the Cauchy constraint may not find the optimum solution by converging to a local minimum of the cost function and thereby introducing some numerical artifacts.
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Ruiz, Alfredo, José María Ranz, Mario Cáceres, and Carmen Segarra. "Chromosomal evolution and comparative gene mapping in the Drosophila repleta species group." Brazilian Journal of Genetics 20, no. 4 (1997): 553–65. http://dx.doi.org/10.1590/s0100-84551997000400003.
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A review of our recent work on the cromosomal evolution of the Drosophila repleta species group is presented. Most studies have focused on the buzzatii species complex, a monophyletic set of 12 species which inhabit the deserts of South America and the West Indies. A statistical analysis of the length and breakpoint distribution of the 86 paracentric inversions observed in this complex has shown that inversion length is a selected trait. Rare inversions are usually small while evolutionary successful inversions, fixed and polymorphic, are predominantly of medium size. There is also a negative correlation between length and number of inversions per species. Finally, the distribution of inversion breakpoints along chromosome 2 is non-random, with chromosomal regions which accumulate up to 8 breakpoints (putative "hot spots"). Comparative gene mapping has also been used to investigate the molecular organization and evolution of chromosomes. Using in situ hybridization, 26 genes have been precisely located on the salivary gland chromosomes of D. repleta and D. buzzatii; another nine have been tentatively identified. The results are fully consistent with the currently accepted chromosomal homologies between D. repleta and D. melanogaster, and no evidence for reciprocal translocations or pericentric inversions has been found. The comparison of the gene map of D. repleta chromosome 2 with that of the homologous chromosome 3R of D. melanogaster shows an extensive reorganization via paracentric inversions and allows to estimate an evolution rate of ~1 inversion fixed per million years for this chromosome
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Chapman, Ross. "Inference of geoacoustic model parameters from acoustic field data: Perspectives on Geoacoustic Inversion." Journal of the Acoustical Society of America 155, no. 3_Supplement (2024): A216. http://dx.doi.org/10.1121/10.0027352.
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Estimation of parameters of geoacoustic models from acoustic field data has been a central research theme in acoustical oceanography and ocean acoustics. During the past several decades, highly efficient numerical inversion techniques have been developed that provide model parameter estimates and their uncertainties based on statistical inference methods. However, the methods are model-based and the inversions are prone to errors related to model mismatch. In any event, the inversions can generate only effective models of the true structure of the ocean bottom, which is generally highly variable over relatively small spatial scales in range and depth. There are also questions about the theory for modelling sound propagation in porous sediment media that raise doubt about the validity of inversion results. In most inversions, a visco-elastic theory is used, but is this the most appropriate propagation model? Another question is about the impact of neglecting shear waves in geoacoustic models. Most inversions assume a fluid model of the ocean bottom. This paper revisits issues that have raised questions about limitations of geoacoustic inversion methods, and discusses the impact of various mitigation measures that have been applied. The paper concludes with musings about new inversion techniques based on machine learning.
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Prado-Alonso, Carlos. "A comprehensive corpus-based analysis of “X Auxiliary Subject” constructions in written and spoken English." Topics in Linguistics 20, no. 2 (2019): 17–32. http://dx.doi.org/10.2478/topling-2019-0007.
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Abstract This paper describes a corpus-based analysis of subject-auxiliary inversion in both spoken and written English. The focus of the analysis is Chen’s (2013) X Auxiliary Subject construction (XASC), where X codes the fronting of a constituent which triggers the inversion of the auxiliary and the subject, as in “Never has trade union loyalty faced a more baffling test” or “What did he do?” On the basis of a statistical analysis using corpora of written and spoken English, it is argued that the distribution of XAS inversion, in the interrogative mood, is related to the degree of an addressor’s involvement in a text. It will be shown that, in the interrogative mood, the more involvement in a text, the more XAS inversions are to be expected. It is also argued that XAS inversions in interrogative clauses can be seen to serve as discourse markers through which an addressor’s involvement is coded in written and spoken English discourse. The analysis will also show that XAS inversions in the declarative mood also serve an interpersonal function, this, however, being inherently tied to the clause-linking function performed by the construction. Furthermore, the data will show that the distribution of XAS inversions in declarative clauses is related to the degree of informational content of the texts in which these inversions occur.
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Devasthale, A., J. Sedlar, and M. Tjernström. "Characteristics of water-vapour inversions observed over the Arctic by Atmospheric Infrared Sounder (AIRS) and radiosondes." Atmospheric Chemistry and Physics Discussions 11, no. 5 (2011): 15801–29. http://dx.doi.org/10.5194/acpd-11-15801-2011.
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Abstract. An accurate characterization of the vertical structure of the Arctic atmosphere is useful in climate change and attribution studies as well as for the climate modelling community to improve projections of future climate over this highly sensitive region. Here, we investigate one of the dominant features of the vertical structure of the Arctic atmosphere, i.e. water-vapour inversions, using eight years of Atmospheric Infrared Sounder data (2002–2010) and radiosounding profiles released from the two Arctic locations (North Slope of Alaska at Barrow and during SHEBA). We quantify the characteristics of clear-sky water vapour inversions in terms of their frequency of occurrence, strength and height covering the entire Arctic for the first time. We found that the frequency of occurrence of water-vapour inversions is highest during winter and lowest during summer. The inversion strength is, however, higher during summer. The observed peaks in the median inversion-layer heights are higher during the winter half of the year, at around 850 hPa over most of the Arctic Ocean, Siberia and the Canadian Archipelago, while being around 925 hPa during most of the summer half of the year over the Arctic Ocean. The radiosounding profiles agree with the frequency, location and strength of water-vapour inversions in the Pacific sector of the Arctic. In addition, the radiosoundings indicate that multiple inversions are the norm with relatively few cases without inversions. The amount of precipitable water within the water-vapour inversion structures is estimated and we find a distinct, two-mode contribution to the total column precipitable water. These results suggest that water-vapour inversions are a significant source to the column thermodynamics, especially during the colder winter and spring seasons. We argue that these inversions are a robust metric to test the reproducibility of thermodynamics within climate models. An accurate statistical representation of water-vapour inversions in models would mean that the large-scale coupling of moisture transport, precipitation, temperature and water vapour vertical structure and radiation are also essentially captured well in such models.
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Devasthale, A., J. Sedlar, and M. Tjernström. "Characteristics of water-vapour inversions observed over the Arctic by Atmospheric Infrared Sounder (AIRS) and radiosondes." Atmospheric Chemistry and Physics 11, no. 18 (2011): 9813–23. http://dx.doi.org/10.5194/acp-11-9813-2011.
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Abstract. An accurate characterization of the vertical structure of the Arctic atmosphere is useful in climate change and attribution studies as well as for the climate modelling community to improve projections of future climate over this highly sensitive region. Here, we investigate one of the dominant features of the vertical structure of the Arctic atmosphere, i.e. water-vapour inversions, using eight years of Atmospheric Infrared Sounder data (2002–2010) and radiosounding profiles released from the two Arctic locations (North Slope of Alaska at Barrow and during SHEBA). We quantify the characteristics of clear-sky water vapour inversions in terms of their frequency of occurrence, strength and height covering the entire Arctic for the first time. We found that the frequency of occurrence of water-vapour inversions is highest during winter and lowest during summer. The inversion strength is, however, higher during summer. The observed peaks in the median inversion-layer heights are higher during the winter half of the year, at around 850 hPa over most of the Arctic Ocean, Siberia and the Canadian Archipelago, while being around 925 hPa during most of the summer half of the year over the Arctic Ocean. The radiosounding profiles agree with the frequency, location and strength of water-vapour inversions in the Pacific sector of the Arctic. In addition, the radiosoundings indicate that multiple inversions are the norm with relatively few cases without inversions. The amount of precipitable water within the water-vapour inversion structures is estimated and we find a distinct, two-mode contribution to the total column precipitable water. These results suggest that water-vapour inversions are a significant source to the column thermodynamics, especially during the colder winter and spring seasons. We argue that these inversions are a robust metric to test the reproducibility of thermodynamics within climate models. An accurate statistical representation of water-vapour inversions in models would mean that the large-scale coupling of moisture transport, precipitation, temperature and water-vapour vertical structure and radiation are essentially captured well in such models.
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Arenas, Conxita, Goran Zivanovic, and Francesc Mestres. "Chromosomal Thermal Index: a comprehensive way to integrate the thermal adaptation of Drosophila subobscura whole karyotype." Genome 61, no. 2 (2018): 73–78. http://dx.doi.org/10.1139/gen-2017-0124.
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Drosophila has demonstrated to be an excellent model to study the adaptation of organisms to global warming, with inversion chromosomal polymorphism having a key role in this adaptation. Here, we introduce a new index (Chromosomal Thermal Index or CTI) to quantify the thermal adaptation of a population according to its composition of “warm” and “cold” adapted inversions. This index is intuitive, has good statistical properties, and can be used to hypothesis on the effect of global warming on natural populations. We show the usefulness of CTI using data from European populations of D. subobscura, sampled in different years. Out of 15 comparisons over time, nine showed significant increase of CTI, in accordance with global warming expectations. Although large regions of the genome outside inversions contain thermal adaptation genes, our results show that the total amount of warm or cold inversions in populations seems to be directly involved in thermal adaptation, whereas the interactions between the inversions content of homologous and non-homologous chromosomes are not relevant.
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Mitsuhata, Yuji, Toshihiro Uchida, and Hiroshi Amano. "2.5‐D inversion of frequency‐domain electromagnetic data generated by a grounded‐wire source." GEOPHYSICS 67, no. 6 (2002): 1753–68. http://dx.doi.org/10.1190/1.1527076.
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Interpretation of controlled‐source electromagnetic (CSEM) data is usually based on 1‐D inversions, whereas data of direct current (dc) resistivity and magnetotelluric (MT) measurements are commonly interpreted by 2‐D inversions. We have developed an algorithm to invert frequency‐Domain vertical magnetic data generated by a grounded‐wire source for a 2‐D model of the earth—a so‐called 2.5‐D inversion. To stabilize the inversion, we adopt a smoothness constraint for the model parameters and adjust the regularization parameter objectively using a statistical criterion. A test using synthetic data from a realistic model reveals the insufficiency of only one source to recover an acceptable result. In contrast, the joint use of data generated by a left‐side source and a right‐side source dramatically improves the inversion result. We applied our inversion algorithm to a field data set, which was transformed from long‐offset transient electromagnetic (LOTEM) data acquired in a Japanese oil and gas field. As demonstrated by the synthetic data set, the inversion of the joint data set automatically converged and provided a better resultant model than that of the data generated by each source. In addition, our 2.5‐D inversion accounted for the reversals in the LOTEM measurements, which is impossible using 1‐D inversions. The shallow parts (above about 1 km depth) of the final model obtained by our 2.5‐D inversion agree well with those of a 2‐D inversion of MT data.
Dissertations / Theses on the topic "Statistical inversions"
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Boucher, Eulalie. "Designing Deep-Learning models for surface and atmospheric retrievals from the IASI infrared sounder." Electronic Thesis or Diss., Sorbonne université, 2024. http://www.theses.fr/2024SORUS145.
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L'observation de la Terre est essentielle pour comprendre et surveiller le comportement complexe de notre planète. Les satellites, équipés d'un certain nombre de capteurs sophistiqués, constituent une plateforme clé à cet égard, offrant une opportunité d'observer la Terre à l'échelle globale et de manière continue. Les techniques d'apprentissage automatique (ML) sont utilisées depuis plusieurs décennies, dans la communauté de la télédétection, pour traiter la grande quantité de données générées quotidiennement par les systèmes d'observation de la Terre. La révolution apportée par les nouvelles techniques de Deep Learning (DL) a toutefois ouvert de nouvelles possibilités pour l'exploitation des observations satellitaires. Cette thèse vise à montrer que des techniques de traitement d'images telles que les réseaux neuronaux convolutifs (CNN), à condition qu'elles soient bien maîtrisées, ont le potentiel d'améliorer l'estimation des paramètres atmosphériques et de surface de la Terre. En considérant les observations à l'échelle de l'image plutôt qu'à l'échelle du pixel, les dépendances spatiales peuvent être prises en compte. De telles techniques sont utilisées dans cette thèse pour l'estimation des températures de surface et atmosphériques, ainsi que pour la détection et la classification des nuages à partir des observations de l'Interféromètre Atmosphérique de Sondage dans l'Infrarouge (IASI). IASI, qui est placé à bord des satellites en orbite polaire Metop, est un sondeur hyperspectral collectant des données sur une large gamme de longueurs d'onde dans l'infrarouge. Chacune est adaptée à l'identification des constituants atmosphériques à différents niveaux de l'atmosphère, ou de paramètres de surface. En plus d'améliorer la qualité des restitutions, de telles méthodes d'Intelligence Artificielle (IA) sont capables de traiter des images contenant des données manquantes, de mieux estimer les événements extrêmes (souvent négligés par les techniques statistiques traditionnelles) et d'estimer les incertitudes des restitutions. Cette thèse montre pourquoi les méthodes d'IA, et en particulier les CNN avec convolutions partielles, devraient constituer l'approche privilégiée pour l'exploitation des observations provenant de nouvelles missions satellitaires telles que IASI-NG ou MTG-S IRS<br>Observing the Earth is vital to comprehend and monitor the complex behaviour of our planet. Satellites, equipped with a number of sophisticated sensors, serve as a key platform for this, offering an opportunity to observe the Earth globally and continuously. Machine Learning (ML) techniques have been used in the remote sensing community for several decades to deal with the vast amount of data generated daily by Earth observation systems. The revolution brought about by novel Deep Learning (DL) techniques has however opened up new possibilities for the exploitation of satellite observations. This research aims to show that image-processing techniques such as Convolutional Neural Networks (CNNs), provided that they are well mastered, have the potential to improve the estimation of the Earth's atmospheric and surface parameters. By looking at the observations at the image scale rather than at the pixel scale, spatial dependencies can be taken into account. Such techniques will be used for the retrieval of surface and atmospheric temperatures, as well as cloud detection and classification from the Infrared Atmospheric Sounding Interferometer (IASI) observations. IASI, onboard the polar orbiting satellites Metop, is a hyperspectral sounder gathering data across a broad range of infrared wavelengths that are suitable to identify atmospheric constituents for a range of atmospheric vertical levels, as well as surface parameters. In addition to improving the quality of the retrievals, such Artificial Intelligence (AI) methods are capable of dealing with images that contain missing data, better estimating extreme events (often overlooked by traditional ML techniques) and estimating retrieval uncertainties. This thesis shows why AI methods should be the preferred approach for the exploitation of observations coming from new satellite missions such as IASI-NG or MTG-S IRS
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Ladrón, de Guevara Cortés Rogelio. "Techniques For Estimating the Generative Multifactor Model of Returns in a Statistical Approach to the Arbitrage Pricing Theory. Evidence from the Mexican Stock Exchange." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/386545.
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This dissertation focuses on the estimation of the generative multifactor model of returns on equities, under a statistical approach of the Arbitrage Pricing Theory (APT), in the context of the Mexican Stock Exchange. Therefore, this research takes as frameworks two main issues: (i) the multifactor asset pricing models, specially the statistical risk factors approach, and (ii) the dimension reduction or feature extraction techniques: Principal Component Analysis, Factor Analysis, Independent Component Analysis and Non-linear Principal Component Analysis, utilized to extract the underlying systematic risk factors. The models estimated are tested using two methodologies: (i) capability of reproduction of the observed returns using the estimated generative multifactor model, and (ii) results of the econometric contrast of the APT using the extracted systematic risk factors. Finally, a comparative study among techniques is carried on based on their theoretical properties and the empirical results.
According to the above stated and as far as we concerned, this dissertation contributes to financial research by providing empirical evidence of the estimation of the generative multifactor model of returns on equities, extracting statistical underlying risk factors via classic and alternative dimension reduction or feature extraction techniques in the field of finance, in order to test the APT as an asset pricing model, in the context of an emerging financial market such as the Mexican Stock Exchange. In addition, this work presents an unprecedented theoretical and empirical comparative study among Principal Component Analysis, Factor Analysis, Independent Component Analysis and Neural Networks Principal Component Analysis, as techniques to extract systematic risk factors from a stock exchange, analyzing the level of sensitivity of the results in function of the technique carried on. In addition, this dissertation represents a mainly empirical exhaustive study where objective evidence about the Mexican stock market is provided by way of the application of four different techniques for extraction of systematic risk factors, to four datasets, in a test window that ranged from two to nine factors.
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Degenhardt, Sheldon. "Weighted-inversion statistics and their symmetry groups /." The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487941504293867.
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Fletcher, R. P. "Statistical inversion of surface parameters from ATSR-2 satellite observations." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267415.
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Boberg, Jonas. "Counting Double-Descents and Double-Inversions in Permutations." Thesis, Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-54431.
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In this paper, new variations of some well-known permutation statistics are introduced and studied. Firstly, a double-descent of a permutation π is defined as a position i where πi ≥ 2πi+1. By proofs by induction and direct proofs, recursive and explicit expressions for the number of n-permutations with k double-descents are presented. Also, an expression for the total number of double-descents in all n-permutations is presented. Secondly, a double-inversion of a permutation π is defined as a pair (πi,πj) where i<j but πi ≥ 2πj. The total number of double-inversions in all n-permutations is presented.
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Fu, Shuai. "Inversion probabiliste bayésienne en analyse d'incertitude." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00766341.
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Ce travail de recherche propose une solution aux problèmes inverses probabilistes avec des outils de la statistique bayésienne. Le problème inverse considéré est d'estimer la distribution d'une variable aléatoire non observée X a partir d'observations bruitées Y suivant un modèle physique coûteux H. En général, de tels problèmes inverses sont rencontrés dans le traitement des incertitudes. Le cadre bayésien nous permet de prendre en compte les connaissances préalables d'experts surtout avec peu de données disponibles. Un algorithme de Metropolis-Hastings-within-Gibbs est proposé pour approcher la distribution a posteriori des paramètres de X avec un processus d'augmentation des données. A cause d'un nombre élevé d'appels, la fonction coûteuse H est remplacée par un émulateur de krigeage (méta-modèle) H chapeau. Cette approche implique plusieurs erreurs de nature différente et, dans ce travail, nous nous attachons a estimer et réduire l'impact de ces erreurs. Le critère DAC a été proposé pour évaluer la pertinence du plan d'expérience (design) et le choix de la loi a priori, en tenant compte des observations. Une autre contribution est la construction du design adaptatif adapté a notre objectif particulier dans le cadre bayésien. La principale méthodologie présentée dans ce travail a été appliquée a un cas d' étude d'ingénierie hydraulique.
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Chebikin, Denis. "Polytopes, generating functions, and new statistics related to descents and inversions in permutations." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43793.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2008.<br>Includes bibliographical references (p. 75-76).<br>We study new statistics on permutations that are variations on the descent and the inversion statistics. In particular, we consider the alternating descent set of a permutation [sigma] = [sigma] 1 [sigma] 2 an defined as the set of indices i such that either i is odd and ai > ui+l, or i is even and au < au+l. We show that this statistic is equidistributed with the 3-descent set statistic on permutations [sigma] = [sigma] 1 [sigma] 2 ... [sigma] n+1 with al = 1, defined to be the set of indices i such that the triple [sigma] i [sigma] i + [sigma] i +2 forms an odd permutation of size 3. We then introduce Mahonian inversion statistics corresponding to the two new variations of descents and show that the joint distributions of the resulting descent-inversion pairs are the same. We examine the generating functions involving alternating Eulerian polynomials, defined by analogy with the classical Eulerian polynomials ... using alternating descents. By looking at the number of alternating inversions in alternating (down-up) permutations, we obtain a new qanalog of the Euler number En and show how it emerges in a q-analog of an identity expressing E, as a weighted sum of Dyck paths. Other parts of this thesis are devoted to polytopes relevant to the descent statistic. One such polytope is a "signed" version of the Pitman-Stanley parking function polytope, which can be viewed as a generalization of the chain polytope of the zigzag poset. We also discuss the family of descent polytopes, also known as order polytopes of ribbon posets, giving ways to compute their f-vectors and looking further into their combinatorial structure.<br>by Denis Chebikin.<br>Ph.D.
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Ars, Sébastien. "Caractérisation des émissions de méthane à l'échelle locale à l'aide d'une méthode d'inversion statistique basée sur un modèle gaussien paramétré avec les données d'un gaz traceur." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLV030/document.
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L'augmentation des concentrations de méthane dans l'atmosphère, directement imputable aux activités anthropiques, induit une accentuation de l'effet de serre et une dégradation de la qualité de l'air. Il existe encore à l'heure actuelle de grandes incertitudes concernant les estimations des émissions des dfférentes sources de méthane à l'échellelocale. Une meilleure caractérisation de ces sources permettrait de mettre en place des politiques d'adaptation et d'att énuation efficaces afin de réduire ces émissions. Nous avons développé une nouvelle méthode de quantificationdes émissions de méthane à l'échelle locale basée sur la combinaison de mesures atmosphériques mobiles et d'un modèle gaussien dans le cadre d'une inversion statistique. Les concentrations atmosphériques du méthane sont mesuréesainsi que celles d'un gaz traceur émis à un flux connu. Ces concentrations en gaz traceur sont utilisées pour sélectionnerla classe de stabilité représentant le mieux les conditions atmosphériques dans le modèle gaussien ainsi qu'à paramétrerl'erreur associée aux mesures et au modèle dans l'inversion statistique. Dans un premier temps, cette nouvelle méthoded'estimation des émissions de méthane a été testée grâce à des émissions contrôlées de traceur et de méthane dontles sources ont été positionnées suivant différentes configurations. J'ai ensuite appliqué cette méthode à deux sites réels connus pour leurs émissions de méthane, une exploitation agricole et une installation de distribution de gaz, afin de tester son applicabilité et sa robustesse dans des conditions plus complexes de répartition des sources de méthane. Cette méthode a permis d'obtenir des estimations des émissions totales des sites robustes prenant en compte la localisation du traceur par rapport aux sources de méthane. L'estimation séparéedes émissions des différentes sources d'un site s'est révélée fortement dépendante des conditions météorologiques durant les mesures. Je me suis ensuite focalisé sur les émissions de méthane associées au secteur des déchets en réalisant un certain nombre de campagnes de mesures au sein d'installations de stockagedes déchets non dangereux et de stations d'épuration. Les résultats obtenus pour ces différents sites montrent la grandevariabilité des émissions de méthane dans le secteur des déchets<br>The increase of atmospheric methane concentrations since the beginning of the industrial era is directly linked to anthropogenic activities. This increase is partly responsible for the enhancement of the greenhouse effect leading to a rise of Earth's surface temperatures and a degradation of air quality. There are still considerable uncertainties regarding methane emissions estimates from many sources at local scale. A better characterization of these sources would help the implementation of effective adaptation and mitigation policies to reduce these emissions.To do so, we have developed a new method to quantify methane emissions from local sites based on the combination of mobile atmospheric measurements, a Gaussian model and a statistical inversion. These atmospheric measurements are carried out within the framework of the tracer method, which consists in emitting a gas co-located with the methane source at a known flow. An estimate of methane emissions can be given by measuring the tracer and methane concentrations through the emission plume coming from the site. This method presents some limitations especially when several sources and/or extended sources can be found on the studied site. In these conditions, the colocation of the tracer and methane sources is difficult. The Gaussian model enables to take into account this bad collocation. It also gives a separate estimate of each source of a site when the classical tracer release method only gives an estimate of its total emissions. The statistical inversion enables to take into account the uncertainties associated with the model and the measurements.The method is based on the use of the measured tracer gas concentrations to choose the stability class of the Gaussian model that best represents the atmospheric conditions during the measurements. These tracer data are also used to parameterize the error associated with the measurements and the model in the statistical inversion. We first tested this new method with controlled emissions of tracer and methane. The tracer and methane sources were positioned in different configurations in order to better understand the contributions of this method compared to the traditional tracer method. These tests have demonstrated that the statistical inversion parameterized by the tracer gas data gives better estimates of methane emissions when the tracer and methane sources are not perfectly collocated or when there are several sources of methane.In a second time, I applied this method to two sites known for their methane emissions, namely a farm and a gas distribution facility. These measurements enabled us to test the applicability and robustness of the method under more complex methane source distribution conditions and gave us better estimates of the total methane emissions of these sites that take into account the location of the tracer regarding methane sources. Separate estimates of every source within the site are highly dependent on the meteorological conditions during the measurements. The analysis of the correlations on the posterior uncertainties between the different sources gives a diagnostic of the separability of the sources.Finally I focused on methane emissions associated with the waste sector. To do so, I carried out several measurement campaigns in landfills and wastewater treatment plants and I also used data collected on this type of sites during other projects. I selected the most suitable method to estimate methane emissions of each site and the obtained estimates for each one of these sites show the variability of methane emissions in the waste sector
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Goto, Isao. "Word Reordering for Statistical Machine Translation via Modeling Structural Differences between Languages." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/189374.
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2015-05-27に本文を差替<br>Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(情報学)<br>甲第18481号<br>情博第532号<br>新制||情||94(附属図書館)<br>31359<br>京都大学大学院情報学研究科知能情報学専攻<br>(主査)教授 黒橋 禎夫, 教授 田中 克己, 教授 河原 達也<br>学位規則第4条第1項該当
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Konečný, Zdeněk. "Statistická analýza složených rozdělení." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229488.
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The probability distribution of a random variable created by summing a random number of the independent and identically distributed random variables is called a compound probability distribution. In this work is described a compound distribution as well as a calculation of its characteristics. Especially, the thesis is focused on studying a special case of compound distribution where each addend has the log-normal distribution and their number has the negative binomial distribution. Here are also described some approaches to estimate the parameters of LN and NB distribution. Further, the impact of these estimates on the final compound distribution is analyzed.
Books on the topic "Statistical inversions"
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Shen, Qiuyang, Jiefu Chen, Xuqing Wu, Yueqin Huang, and Zhu Han. Statistical Inversion of Electromagnetic Logging Data. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-57097-2.
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(Argentina), Buenos Aires. Buenos Aires 2000: Plan de inversiones : inversión estratégica para reposicionar a la ciudad de Buenos Aires : por la nueva Buenos Aires. [Partido Justicialista, 1996.
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Ecuador. Ministerio de Bienestar Social. Plan social: Resumen de inversiones 1994. Instituto Nacional de Estadística y Censos, 1994.
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Bour, Juan L. Inversión en educación universitaria en Argentina. Fundación de Investigaciones Económicas Latinoamericanas, 1989.
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Banco Central de Honduras. Subgerencia de Estudios Económicos., ed. Inversión extranjera directa en Honduras: Período 1993-2003. Banco Central de Honduras, Subgerencia de Estudios Económicos, 2004.
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Lurati, Mónica. Encuesta sobre inversión en la industria manufacturera. Fundación de Investigaciones Económicas Latinoamericanas, 1993.
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Cámara de Comercio de Santiago. Departamento de Estudios Económicos. Inversión chilena detectada en el exterior: Informe 2000. Editorial Cámara de Comercio de Santiago, 2000.
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Consejo Técnico de Inversiones (Argentina), ed. La transformación económica argentina: Privatizaciones, integración al MERCOSUR y boom de inversiones. Consejo Técnico de Inversiones, 1998.
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Panama. Dirección de Estadística y Censo., ed. Estadística panameña, situación económica: Inversión directa extranjera, años 1990-2000. República de Panamá, Contraloría General, Dirección de Estadística y Censo, 2002.
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Chile. Ministerio de Planificación y Cooperación. División de Planificación Regional. Serie regionalizada de la inversión pública efectiva 1990-2000. MIDEPLAN, División de Planificación Regional, 2001.
Find full textBook chapters on the topic "Statistical inversions"
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Simon, Martin. "Statistical inversion." In Anomaly Detection in Random Heterogeneous Media. Springer Fachmedien Wiesbaden, 2015. http://dx.doi.org/10.1007/978-3-658-10993-6_4.
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Doicu, Adrian, Thomas Trautmann, and Franz Schreier. "Statistical inversion theory." In Numerical Regularization for Atmospheric Inverse Problems. Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-05439-6_4.
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Sabbagh, Harold A., R. Kim Murphy, Elias H. Sabbagh, John C. Aldrin, and Jeremy S. Knopp. "Robust Statistical Estimators." In Computational Electromagnetics and Model-Based Inversion. Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4419-8429-6_13.
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Abdelrahman, E. M., and M. M. Gobashy. "A Statistical Approach to Depth Determination from Gravity Gradients." In Geophysical Data Inversion Methods and Applications. Vieweg+Teubner Verlag, 1990. http://dx.doi.org/10.1007/978-3-322-89416-8_12.
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Fitzsimmons, Maxwell, and Herb Kunze. "Circle Inversion IFS." In Springer Proceedings in Mathematics & Statistics. Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-99719-3_8.
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Ng, Kai Wang. "Inversion of Bayes’ Formula for Events." In International Encyclopedia of Statistical Science. Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-04898-2_314.
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Maillard, J. M. "Star-Triangle and Inversion Relations in Statistical Mechanics." In Critical Phenomena. Birkhäuser Boston, 1985. http://dx.doi.org/10.1007/978-1-4899-6650-6_15.
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Bart, A. G., N. P. Alexeyeff, N. P. Klochkova, and N. Botchkina. "Partially Inversion of Functions for Statistical Modelling of Regulatory Systems." In Advances in Stochastic Simulation Methods. Birkhäuser Boston, 2000. http://dx.doi.org/10.1007/978-1-4612-1318-5_21.
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Zhdanov, Michael S. "Joint Inversion Based on Analytical and Statistical Relationships Between Different Physical Properties." In Advanced Methods of Joint Inversion and Fusion of Multiphysics Data. Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-6722-3_8.
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Borodin, V. V., and G. R. Minasian. "Statistical Formulation of Ray, Interference and Mode Acoustic Tomography and Its Potential Accuracy Evaluation." In Full Field Inversion Methods in Ocean and Seismo-Acoustics. Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-015-8476-0_16.
Full textConference papers on the topic "Statistical inversions"
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Alyousuf, Taqi, and Li Yaoguo. "Inversion Using Adaptive Physics-Based Neural Network: Application to Magnetotelluric Inversion." In International Petroleum Technology Conference. IPTC, 2022. http://dx.doi.org/10.2523/iptc-22504-ea.
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Abstract In order to develop a geophysical earth model that is consistent with the measured geophysical data, two types of inversions are commonly used: a physics-based regularized inversion and a statistical-based machine learning inversion. In nonlinear problems, deterministic regularized inversion usually necessitates a good starting model to prevent possible local minima. The neural networks inversion requires large training data sets, which makes its generalizability limited. To overcome the limitation of physics-based regularized inversion and a statistical-based machine learning inversion and combine the benefits of both one inversion scheme, we developed a new physics-based neural network (PBNN) inversion algorithm. In our PBNN inversion, we include machine learning constraints into the regularized inversion using a coupling model objective function. The coupling objective function aims to minimize the difference between the recovered model through regularized inversion and the network-predicted reference model. We update the reference model using either a fully-trained network or an adaptively-trained network. The fully trained PBNN has the ability to collect all of the connections between data and models through a pseudoinverse operator. However, for geophysical inversion applications, particularly in the exploratory setting, this approach is unlikely to become feasible. Neural networks may struggle to extract complicated correlations from data when given insufficient data observations. The technique is impractical for practical usage due to the quantity of training required. In our novel adaptively PBNN algorithm, there is no need to prepare a training data set. At each iteration, the adaptively-PBNN algorithm retrains using the recovered models from the regularized inversion and their related data. The regularized inversion's recovered resistivity models are sufficient to guide neural network predictions towards the true model. One unique advantage is that the approach’s ability to fully use all intermediate models from the regularized inversion that were commonly discarded and apply them to the network training. When applied to synthetic MT data, we show that our technique is capable of reconstructing high-resolution resistivity models.
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Noordin, Firdaus Bin Mohamed, Ibrahim Abdelgaffar Seddik, Maniesh Singh, et al. "Mapping Injection Water Slumping and Reservoir Boundaries Using Real-Time ANN 2D Inversion of Extra Deep Azimuthal LWD Resistivity Measurements." In 2022 SPWLA 63rd Annual Symposium. Society of Petrophysicists and Well Log Analysts, 2022. http://dx.doi.org/10.30632/spwla-2022-0024.
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Extra deep azimuthal resistivity (EDAR) measurements are widely used for proactive geosteering and reservoir mapping. Real-time decisions are usually supported with data inversion results and uncertainty quantification based on 1D layer-cake models. A richer 2D model is required in complex scenarios, such as the irregular shaped water slumping observed in this Abu Dhabi Lower Cretaceous limestone reservoir. The inversion based on the Levenberg-Marquardt method successively runs forward simulations matching the measured and synthetic data. Inversion with a 1D layered model provides good data match and functional results on most intervals along the horizontal borehole. For intervals where this is not the case, the inversion continues with a 2D model covering a variety of lateral inhomogeneity scenarios. The challenge of fast 2D forward simulation for this model is solved by the application of an Artificial Neural Network (ANN) whose performance is applicable for real-time applications. Injection water override and the base of the reservoir boundary were detected using 1D inversions along the horizontal borehole at distances of 14-43 ft and 6-20 ft TVD respectively. Continuous uncertainty corridors for surfaces of interest were calculated using a linear deterministic approach and visualized on a curtain section. Water-saturated formation is conductive and prevents detection of any layers beyond. Therefore, we calculate only one-sided (downward) uncertainty estimate for the slumping water position which is 2-15 ft along the well. The uncertainty estimate for the base is two-sided and varies from 0.1 to 7 ft along the well. Using statistical analysis of the inversion results, we show joint uncertainty for all model parameters at selected intervals. On exceptional intervals, where the 1D model turned out to be inappropriate, 2D inversion was applied. For example, when the azimuthal measurements indicate the presence of a conductive zone on the side and the top. Our 2D model covers this case and the 2D inversion provides an improved data match and agrees with the a priori information on the reservoir. The results of 2D inversions on consecutive intervals eventually constitute a laterally consistent 3D structure of the reservoir. We demonstrate real-time 2D inversion of EDAR data based on scenario-specific models. Real-time performance is achieved by utilizing a forward solver using a pre-trained ANN. 2D inversion was applied along intervals, where EDAR measurements indicated non-parallel bedding of reservoir base below the well and slumping water above it. Combined 1D and 2D inversion results comprise a laterally consistent 3D model and leads to better understanding of the reservoir structure.
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Mukerji, Tapan, Arild Jørstad, Gary Mavko, and John Reidar Granli. "Applying statistical rock physics and seismic inversions to map lithofacies and pore fluid probabilities in a North Sea reservoir." In SEG Technical Program Expanded Abstracts 1998. Society of Exploration Geophysicists, 1998. http://dx.doi.org/10.1190/1.1820633.
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Nguyen, Viet, Armando Vianna, Karel Steviano, Ahmad Zulharman, Ramadhana Aristya, and Hendry Lie. "Strategic Well Landing and Risk Mitigation in Heterogeneous Formation With Deterministic Automated Inversion and Remote Monitoring." In International Petroleum Technology Conference. IPTC, 2022. http://dx.doi.org/10.2523/iptc-22230-ms.
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Abstract The K-W horizontal well was drilled to produce gas reserves from A sand and oil reserves from B sand. Accurate landing of the well in the target B sand is critical for the placement of the 6 1/8" lateral section within the reservoir. The main objective of reservoir navigation in the 8 ½" build section is to detect and map the reservoir top as early as possible to smoothly place the well 10ft TVD below the top of the B sand with an inclination of 85 degrees. Several operational risks have been identified during pre-well feasibility study, including reservoir resistivity and thickness variation, presence of intra-shale, presence of faults, and depth uncertainty from old seismic data. To mitigate the risks, extra-deep azimuthal resistivity technology was included in the bottom hole assembly. The real-time reservoir navigation was carried out remotely with frequent updates on real-time log analysis and observations provided to the client via a 24/7 virtual meeting. The service provider implemented a newly introduced centralized reservoir navigation system, which provides quicker data handling and seamless job handover. Multiple deterministic inversion workflows with constrained parameters were set-up to process the real-time extra-deep resistivity measurement, maximizing reservoir detection and mapping capability. As a result, the 8 ½" hole section of K-W well has been landed within the target formation. After the last marker, log signatures indicated good correlation with offset well data, extra-deep resistivity detected the presence of sand from a distance of approximately 34ft TVD. However, the automated inversion multi-layer mapping indicated possible reservoir pinch-out. A decision was made by the operator to further drop inclination and cut down through the entire formation. When the well crossed the expected reservoir top, extra-deep resistivity quickly decreased and log signatures indicated the presence of a thin sand before entering the basal shale formation, which was accurately mapped by inversions. In the post-well phase, deterministic uncertainty and the new statistical uncertainty analysis were run to evaluate the position of the main boundaries defined by extra-deep reading measurements. 1) deterministic approach is instantaneous and based on the linearized dependency between measurements and model parameters; 2) statistical quantification is based on the analysis of set of intermediate inversion models and includes industry-standard P50 visualization. This paper presents a case history of implementing extra-deep resistivity technology to overcome geological uncertainties during well landing in a complex environment. The novel approach of utilizing multiple deterministic inversion workflows maximized detection capability and accurate mapping of the reservoir structure, allowing early risk mitigation even before entering the target reservoir.
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Clegg, Nigel, Seth Nolan, Alban Duriez, et al. "Confidence in Subsurface Inversion Models Generated from Electromagnetic Logging While Drilling Data." In SPE Annual Technical Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/210374-ms.
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Abstract Identifying a well's stratigraphic position from azimuthal electromagnetic (EM) data requires integrating data from multiple depths of investigation. As a well's position within the stratigraphy can be constantly changing, and formations and fluids show considerable lateral variability, this process is difficult to do manually. To simplify this, inversion algorithms are deployed to represent EM logging while drilling (LWD) measurements as models reflecting the geology. Inversion results are not a direct measurement, therefore confidence in the results is critical. Real-time well placement decisions are routinely made on the output of EM inversions. It is critical to understand that these are models, not direct measurements, therefore verification of the results is essential. This paper discusses the workflows and tools available to interrogate the models generated to give high confidence in the results with a focus on a new deep EM tool deployed in a complex geological environment. The deployment of established EM tools in the same bottom hole assembly (BHA) provides independent verification of the results alongside statistical analysis of the inversion. In many complex depositional environments, the resultant geology is not layer cake. Formations can pinch out or show considerable lateral variability. In these environments it is extremely challenging and sometimes impossible to track a single layer or boundary. We examine a case study from Alaska in a complex shallow marine depositional environment. The target sands were expected to show considerable lateral variability with pinch outs and multiple shale lenses and layers. Deployment of a new, deep azimuthal EM tool with an associated inversion algorithm provided a geological model representing the distribution of the target formations. The stratigraphy was comprised of a complex distribution of sands and shales, many penetrated by the wellbore, with others distributed away from the wellbore based on the depth of investigation of the EM measurements. If this model is the primary tool for mapping the formations and steering to penetrate the most productive zones, it is critical to understand the results and have high confidence in them. The second tool in the BHA, the established azimuthal resistivity tool, provided an opportunity to directly compare the azimuthal data with the inversion result from the new tool to critique the inversion results and help to understand this complex geological environment. The complexity of integrating the data from multiple azimuthal images with different depths of investigation, based on multiple transmitter-receiver spacings and transmission frequencies, demonstrates the need for inversion algorithms to convert the EM field data to a simple-to-understand representation of the geology. This case study provides proof of the quality of the model, especially in such a complex geological environment, allowing high confidence in the deployment of this new tool for well path optimization.
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Andreasi, F. Golfré, C. Brambilla, S. Re, F. Miotti, T. Wiik, and K. Hokstad. "Multi-Geophysics for Reservoir Characterization: A Comparison of Deterministic and Statistical Inversion Methodologies." In First EAGE Conference on Seismic Inversion. European Association of Geoscientists & Engineers, 2020. http://dx.doi.org/10.3997/2214-4609.202037041.
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Burksaitiene, Daiva, and Kristina Garskaite-Milvydiene. "Cross-Border Mergers and Acquisitions Factors in Joining the European Union Countries." In Contemporary Issues in Business, Management and Education. Vilnius Gediminas Technical University, 2017. http://dx.doi.org/10.3846/cbme.2017.076.
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Mergers and acquisitions (M&amp;As) are increasingly being used in the business world, and this process plays an important role in economic theory and lays the foundations for sustainable business development. The global recovery in foreign direct investment (FDI) was strong in 2015, with global FDI flows jumping by 38%, their highest level since the global economic and financial crisis of 2008–2009. A surge in cross-border M&amp;As to $721 billion, from $432 billion in 2014, was the principal factor behind the global rebound. These M&amp;As were partly driven by very large corporate reconfigurations by multinational enterprises (MNEs), i.e. changes in legal or ownership structures, including shifting their headquarters for strategic reasons and tax inversions. This paper examines the key M&amp;As stimulating strategic objectives and causes, and ways of this process, as well as the cross-border M&amp;As market activity. The objective of this paper is to identify ways, purposes and reasons of M&amp;As transactions, and to present the factors influencing this process and market activity. The object of this research is the M&amp;As transactions market. Research methodology of this paper is based on scientific literature and statistical information systematic, comparative, logical and econometric analysis.
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Rai, Jagdish, and Charles M. Bowden. "Quantum noise effects in superfluorescence from dense atomic systems." In OSA Annual Meeting. Optica Publishing Group, 1989. http://dx.doi.org/10.1364/oam.1989.tus7.
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Cooperative emission from a collection of atoms prepared in an initial state of complete inversion has been studied extensively in the past. In this paper we study the cooperative emission in dense atomic systems where there is a large average number of atoms per cubic resonance wavelength. For systems with such large densities, effects of the induced dipole-dipole interaction among neighboring atoms become important. Recently it has been shown that such interatomic interaction in a dense atomic system can lead to novel nonlinear effects.1,2 The induced dipole-dipole interaction for two-level atoms appears as a nonlinear inversion dependent renormalization of the atomic resonance frequency which gives rise to a set of modified Maxwell-Bloch equations. We study the phenomenon of superfluorescence (SF) and amplified spontaneous emission (ASE) using the modified Maxwell-Bloch equations. Statistical effects of amplified quantum stochastic processes are analyzed in SF and ASE. Phase wave statistics are analyzed in the linear regime of coherent pulse buildup. Amplified effects in the nonlinear regime in the SF to ASE transition region are statistically analyzed. Dipole dephasing due to collisions is found to play an important role.
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Meucci, R., M. Ciofini, F. T. Arecchi, and Peng-ye Wang. "Two-peaked passage time statistics in a Q-switched CO2 laser near threshold." In Nonlinear Dynamics in Optical Systems. Optica Publishing Group, 1992. http://dx.doi.org/10.1364/nldos.1992.fa5.
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In this paper we report experimental evidence of two-peaked transient time statistics in a single mode CO2 laser and we show that this phenomenon is due to the population inversion fluctuations. The same statistical feature has been also observed in dye1 and semiconductor2 lasers. However, in the first case two-peaked passage time distributions arise from the coupling between two transverse modes, while in the second case they are induced by the correlation between two successive pulses.
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Szacherski, Pascal, Jean-Francois Giovannelli, and Pierre Grangeat. "Joint Bayesian hierarchical inversion-classification and application in proteomics." In 2011 IEEE Statistical Signal Processing Workshop (SSP). IEEE, 2011. http://dx.doi.org/10.1109/ssp.2011.5967636.
Full textReports on the topic "Statistical inversions"
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Miller, Eric L., and Alan S. Willsky. A Multiscale, Statistically-Based Inversion Scheme for Linearized Inverse Scattering Problems. Defense Technical Information Center, 1994. http://dx.doi.org/10.21236/ada458526.
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Heinrich, Carolyn, and Yeri López. Does Community Participation Produce Dividends in Social Investment Fund Projects? Inter-American Development Bank, 2007. http://dx.doi.org/10.18235/0011175.
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Social investment funds, a widely used tool of development efforts, aim to support and strengthen local capacity for effective implementation of social and economic infrastructure projects through participatory, community-driven approaches. This working paper investigates whether these participatory methods improve the outcomes of education projects and community members' perceptions of their effectiveness using data from an impact evaluation of the third phase of the Fondo Hondureño de Inversión Social (FHIS). The study also makes an important contribution with more carefully defined and explicit measures of individuals' participation in community projects. In regards to the outcome, the authors do not find statistically significant effects of the education projects on academic outcomes of school-aged youth, but they do observe positive, statistically significant relationships between the use of participatory methodologies and household opinions of the projects, as well as between households' level of participation and their opinions of the projects.
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Quijada, Sebastián. Normas de la Eurostat para contabilidad de los Asociaciones Público-Privada (APP) y modelo United Kingdom Private Finance Initiative (UK PFI). Inter-American Development Bank, 2011. http://dx.doi.org/10.18235/0007598.
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Presentación expuesta durante el Cuarto Encuentro Técnico en Materia de Estructuración de Proyectos de Asociación Público-Privada, llevado a cabo en Tuxtla Gutiérrez, Chiapas, el 16,17 y 18 de febrero de 2011. La Eurostat (Statistical Office of European Communities), creada en 1953, es la oficina de estadísticas de la Comunidad Europea que produce datos sobre la Unión Europea y promueve la armonización de los métodos estadísticos de sus estados miembros. La Eurostat ha desarrollado una serie de criterios que tiene como finalidad homologar las interpretaciones contables respecto a los activos (pasivos) que son generados como consecuencia de la ejecución de contratos de Asociación Público Privada (APP). Esta presentación tiene como fin analizar la Normas de Eurostat y el Modelo PFI (Private Finance Initiative) adoptado en el Reino Unido. En cuanto a este país europeo, se resaltan algunos casos de estudio que han sido exitosos utilizando este enfoque de inversión.