Search results for "Statistical Model"
showing 10 items of 163 documents
Contributions of statistical modelling for the understanding of the nivo-glaciological dynamics of a small arctic glacial basin (Austre Lovén glacier…
2021
Since the middle of the 19th century, the Earth has experienced a climate shift marked by a high rise in temperature (+ 0.85 °C over the period 1880-2012). The Arctic is the region of the world that is warming the most rapidly, at a rate of 2 to 3 times faster than the global average. In this context, all components of the Arctic cryosphere are experiencing a change in their dynamics. Because of their direct links with the atmosphere, glaciers are among the best indicators of these climate variations. Like other glaciers on the globe, the glaciers of Svalbard, which cover 60% of the archipelago’s surface, have been retreating since the end of the Little Ice Age. This retreat, which is refle…
Urban monitoring using multi-temporal SAR and multi-spectral data
2006
In some key operational domains, the joint use of synthetic aperture radar (SAR) and multi-spectral sensors has shown to be a powerful tool for Earth observation. In this paper, we analyze the potentialities of combining interferometric SAR and multi-spectral data for urban area characterization and monitoring. This study is carried out following a standard multi-source processing chain. First, a pre-processing stage is performed taking into account the underlying physics, geometry, and statistical models for the data from each sensor. Second, two different methodologies, one for supervised and another for unsupervised approaches, are followed to obtain features that optimize the urban rela…
The Taguchi Method Application to Improve the Quality of a Sustainable Process
2018
Taguchi's method has always been a method used to improve the quality of the analyzed processes and products. This research shows an unusual situation, namely the modeling of some parameters, considered technical parameters, in a process that is wanted to be durable by improving the quality process and by ensuring quality using an experimental research method. Modern experimental techniques can be applied in any field and this study reflects the benefits of interacting between the agriculture sustainability principles and the Taguchi's Method application. The experimental method used in this practical study consists of combining engineering techniques with experimental statistical modeling …
Syntagmatic and Paradigmatic Associations in Information Retrieval
2003
It is shown that unconscious associative processes taking place in the memory of a searcher during the formulation of a search query in information retrieval — such as the production of free word associations and the generation of synonyms — can be simulated using statistical models that analyze the distribution of words in large text corpora. The free word associations as produced by subjects on presentation of stimulus words can be predicted by applying first-order statistics to the frequencies of word co-occurrences as observed in texts. The generation of synonyms can also be conducted on co-occurrence data but requires second-order statistics. Both approaches are compared and validated …
The computation of word associations
2002
It is shown that basic language processes such as the production of free word associations and the generation of synonyms can be simulated using statistical models that analyze the distribution of words in large text corpora. According to the law of association by contiguity, the acquisition of word associations can be explained by Hebbian learning. The free word associations as produced by subjects on presentation of single stimulus words can thus be predicted by applying first-order statistics to the frequencies of word co-occurrences as observed in texts. The generation of synonyms can also be conducted on co-occurrence data but requires second-order statistics. The reason is that synony…
Predicting gully occurrence at watershed scale: Comparing topographic indices and multivariate statistical models
2020
In this study, the ability of five topographic indices to predict the gully trajectories observed in two adjacent watersheds located in Sicily (Italy) was evaluated. Two of these indices, named MSPI and MTWI, as far as we know, have never been employed to this aim. They were obtained by multiplying the stream power index (SPI) and the topographic wetness index (TWI), respectively, by the convergence index (CI). The predictive ability of the topographic indices was measured by using both cut-off independent (AUC: area under the receiver operating characteristic curve) and dependent statistics (Cohen's kappa index κ, sensitivity, specificity). These statistics were calculated also for 100 MAR…
Statistical Modeling and Analysis of Mobile-to-Mobile Fading Channels in Cooperative Networks Under Line-of-Sight Conditions
2009
Published version of an article from the journal: Wireless Personal Communications. The original publication is available at Springerlink. http://dx.doi.org/10.1007/s11277-009-9721-4 Recently, mobile-to-mobile (M2M) cooperative network technology has gained considerable attention for its promise of enhanced system performance with increased mobility support. As this is a new research field, little is known about the statistical properties of M2M fading channels in cooperative networks. So far, M2M fading channels have mainly been modeled under the assumption of non-line-of-sight (NLOS) conditions. In this paper, we propose a new model for M2M fading channels in amplify-and-forward relay lin…
A Study of the Influence of Shadowing on the Statistical Properties of the Capacity of Mobile Radio Channels
2008
Article from the journal: Wireless Personal Communications The original publication is available at www.springerlink.com : http://dx.doi.org/10.1007/s11277-008-9545-7 This paper studies the influence of shadowing on the statistical properties of the channel capacity. The problem is addressed by using a Suzuki process as an appropriate statistical channel model for land mobile terrestrial channels. Using this model, exact solutions for the probability density function (PDF), cumulative distribution function (CDF), level-crossing rate (LCR), and average duration of fades (ADF) of the channel capacity are derived. The results are studied for different levels of shadowing, corresponding to diff…
Agritourism and local development: A methodology for assessing the role of public contributions in the creation of competitive advantage
2018
Abstract Agriculture has been an economic mainstay of countries throughout history. Recently, its importance and essential role in local and regional growth and development have also received due acknowledgment. However, agritourism entrepreneurs often lack the necessary means, when relying only on their own funds alone. For these reasons, targeted aid measures are provided at the regional, national and European levels, provided they fulfill specified subjective and objective eligibility criteria. This investigation aims at understanding the rationale, if any, according to which the Public Administration allots such contributions. To this end, a two-tiered analysis was conducted on the data…
Bovine paramphistomosis in Galicia (Spain): Prevalence, intensity, aetiology and geospatial distribution of the infection
2013
12 páginas, 5 figuras, 4 tablas.