Search results for "Uncertainty"
showing 10 items of 1010 documents
Cardiovascular disease burden from ambient air pollution in Europe reassessed using novel hazard ratio functions
2019
Abstract Aims Ambient air pollution is a major health risk, leading to respiratory and cardiovascular mortality. A recent Global Exposure Mortality Model, based on an unmatched number of cohort studies in many countries, provides new hazard ratio functions, calling for re-evaluation of the disease burden. Accordingly, we estimated excess cardiovascular mortality attributed to air pollution in Europe. Methods and results The new hazard ratio functions have been combined with ambient air pollution exposure data to estimate the impacts in Europe and the 28 countries of the European Union (EU-28). The annual excess mortality rate from ambient air pollution in Europe is 790 000 [95% confidence i…
New Refinements of the McKay Conjecture for Arbitrary Finite Groups
2004
Let $G$ be an arbitrary finite group and fix a prime number $p$. The McKay conjecture asserts that $G$ and the normalizer in $G$ of a Sylow $p$-subgroup have equal numbers of irreducible characters with degrees not divisible by $p$. The Alperin-McKay conjecture is a version of this as applied to individual Brauer $p$-blocks of $G$. We offer evidence that perhaps much stronger forms of both of these conjectures are true.
A Spatial Multilevel Analysis of Italian SMEs Productivity
2009
Abstract In this paper, we adapt multilevel analysis methods to investigate the spatial variability of SMEs' productivity across the Italian territory, and account for differences in the socio-economic context. Our results suggest that to properly capture the variability of the data, it is important to allow for both spatial mean and slope effects. Social decay has the expected negative impact. However, while this effect is larger on firms with smaller capital intensity, firms with higher capital intensity seem to be less affected by geography. Greater territorial heterogeneity emerges among those firms with lower capital to labour ratios. Une analyse spatiale a plusieurs niveaux de la prod…
Stochastic multicriteria evaluation of district heating systems considering the uncertainties
2018
It is of great importance to choose a suitable district heating (DH) system for a specific DH area from the economics, environment and energy (3E) points of view. This is a multicriteria decision making problem, in which the criteria performance values (PVs) and weighting are characterized by uncertain or imprecise information. In this study, seven candidate DH systems are evaluated from the viewpoints of 3E by the stochastic multicriteria acceptability analysis (SMAA) method. SMAA is able to handle the uncertainties of the criteria PVs and the weighting at the same time. These uncertainties are very common and typical in real-life, but in most cases are not treated judiciously or just negl…
Investigation of flow and heat transfer in corrugated passages—I. Experimental results
1996
Abstract An experimental and numerical study of flow and heat transfer was conducted for a crossed-corrugated geometry, representative of compact heat exchangers including air preheaters for fossil-fuelled power plant. In this paper, we describe the method of applying thermochromic liquid crystals and true-colour image processing to give local Nusselt number distribution over the surface, and average Nu, both of quantitative reliability; a careful uncertainty analysis is also presented. Typical experimental results for heat transfer and pressure drop are presented and discussed for various geometries and Reynolds numbers, and are compared with literature data. Numerical predictions are disc…
Simplified Energy Model and Multi-Objective Energy Consumption Optimization of a Residential House
2022
Featured Application: The potential application of the proposed model is a computationally inexpensive semi- or fully automated system for the optimization of operation in residential buildings in terms of energy consumption. Some analyses state that buildings contribute to overall energy consumption by 20–40%, which, in the context of the recent geopolitical energy crisis, makes them a critical issue to study. Finding solutions for better energy management in buildings can have a significant impact on the energy sector, thus reducing EU energy dependencies and contributing to the fulfillment of the REPowerEU goals. This paper focuses on proposing a simplified model of a residential house c…
A pre-processing and network analysis of GPS tracking data
2020
Global Positioning System (GPS) devices afford the opportunity to collect accurate data on unit movements from temporal and spatial perspectives. With a special focus on GPS technology in travel surveys, this paper proposes: (1) two algorithms for the pre-processing of GPS data in order to deal with outlier identification and missing data imputation; (2) a clustering approach to recover the main points of interest from GPS trajectories; and (3) a weighted-directed network, which incorporates the most relevant characteristics of the GPS trajectories at an aggregate level. A simulation study shows the goodness-of-fit of the imputation data algorithm and the robustness of the clustering algori…
Using SMAA-2 method with dependent uncertainties for strategic forest planning
2006
Abstract Uncertainty included in forest variables is normally ignored in forest management planning. When the uncertainty is accounted for, it is typically assumed to be independently distributed for the criteria measurements of different alternatives. In forest management planning, the factors introducing the uncertainty can be classified into three main sources: the errors in the basic forestry data, the uncertainty of the (relative) future prices of timber, and the uncertainty in predicting the forest development. Due to the nature of these error sources, most of the involved uncertainties can be assumed to be positively correlated across the alternative management plans and/or criteria.…
Identification and Robust Control of a Quadratic DC/DC Boost Converter by Hammerstein Model
2015
This paper deals with the theoretical framework definition and the experimental application of the Hammerstein (HM) identification and related robust control technique to a quadratic dc/dc single-switch boost (Q-boost) converter. A set of fourth-order transfer functions (TFs) has been identified with the Hammerstein approach, on the basis of a pseudorandom-binary-sequence (PRBS) excitation signal. The set of identified TFs has been then used to design a suitable robust control technique, able to properly deal with the converter parameter uncertainty and load variations. The proposed approach has been tested in numerical simulation and validated experimentally on a suitably developed test se…
Functional principal component analysis for multivariate multidimensional environmental data
2015
Data with spatio-temporal structure can arise in many contexts, therefore a considerable interest in modelling these data has been generated, but the complexity of spatio-temporal models, together with the size of the dataset, results in a challenging task. The modelization is even more complex in presence of multivariate data. Since some modelling problems are more natural to think through in functional terms, even if only a finite number of observations is available, treating the data as functional can be useful (Berrendero et al. in Comput Stat Data Anal 55:2619–2634, 2011). Although in Ramsay and Silverman (Functional data analysis, 2nd edn. Springer, New York, 2005) the case of multiva…