Search results for " Collection"
showing 10 items of 710 documents
The influence of rainfall time resolution for urban water quality modelling
2010
The objective of this paper is the definition of a methodology to evaluate the impact of the temporal resolution of rainfall measurements in urban drainage modelling applications. More specifically the effect of the temporal resolution on urban water quality modelling is detected analysing the uncertainty of the response of rainfall–runoff modelling. Analyses have been carried out using historical rainfall–discharge data collected for the Fossolo catchment (Bologna, Italy). According to the methodology, the historical rainfall data are taken as a reference, and resampled data have been obtained through a rescaling procedure with variable temporal windows. The shape comparison between ‘true’…
Uncertainty in urban flood damage assessment due to urban drainage modelling and depth-damage curve estimation
2010
Due to the increased occurrence of flooding events in urban areas, many procedures for flood damage quantification have been defined in recent decades. The lack of large databases in most cases is overcome by combining the output of urban drainage models and damage curves linking flooding to expected damage. The application of advanced hydraulic models as diagnostic, design and decision-making support tools has become a standard practice in hydraulic research and application. Flooding damage functions are usually evaluated by a priori estimation of potential damage (based on the value of exposed goods) or by interpolating real damage data (recorded during historical flooding events). Hydrau…
Parent-Child Similarity in Environmental Attitudes: A Pairwise Comparison
2012
Are adolescents’ environmental attitudes similar to their parents’ attitudes? The main objective of this study is to examine what quantitative associations, if any, exist in parent-child environmental attitudes within the family. The survey data was collected assessing attitudes toward the environment and nature from 15-year-old students (n = 237) and their parents (n = 212) in Finland. A significant positive correlation emerged in environmental attitudes between mothers and fathers. Interestingly, the results revealed some indicative evidence that girls’ environmental attitudes could relate more to their father's than mother's attitudes. Girls were as positive in their environmental attitu…
Norm values for eosinophil cationic protein in nasal secretions: influence of specimen collection
1999
Background Eosinophil granulocytes play an important role in allergic inflammation of the nasal mucosa. Eosinophil cationic protein (ECP) is a specific eosinophil granule protein released upon activation of these cells. ECP concentration in nasal secretions has been demonstrated to be a good marker for the activity of eosinophilic nasal mucosal inflammation. The clinical use of such a marker requires defined values which are regarded as pathological or within normal range. In analyses of nasal secretion samples, the sampling method has an important influence on the data obtained. Objective We investigated ECP levels in nasal secretions (NS) of healthy volunteers obtained by seven different …
Two Half-Truths Make a Whole? On Bias in Self-Reports and Tracking Data
2019
The pervasive use of mobile information technologies brings new patterns of media usage, but also challenges to the measurement of media exposure. Researchers wishing to, for example, understand the nature of selective exposure on algorithmically driven platforms need to precisely attribute individuals’ exposure to specific content. Prior research has used tracking data to show that survey-based self-reports of media exposure are critically unreliable. So far, however, little effort has been invested into assessing the specific biases of tracking methods themselves. Using data from a multimethod study, we show that tracking data from mobile devices is linked to systematic distortions in sel…
Selection correction in panel data models: An application to the estimation of females' wage equations
2007
In recent years a number of panel estimators have been suggested for sample selection models, where both the selection equation and the equation of interest contain individual effects which are correlated with the explanatory variables. Not many studies exist that use these methods in practise. We present and compare alternative estimators, and apply them to a typical problem in applied econometrics: the estimation of the wage returns to experience for females. We discuss the assumptions each estimator imposes on the data, and the problems that occur in our applications. This should be particularly useful to practitioners who consider using such estimators in their own application. All esti…
B-Spline Estimation in a Survey Sampling Framework
2021
Nonparametric regression models have been used more and more over the last years to model survey data and incorporate efficiently auxiliary information in order to improve the estimation of totals, means or other study parameters such as Gini index or poverty rate. B-spline nonparametric regression has the benefit of being very flexible in modeling nonlinear survey data while keeping many similarities and properties of the classical linear regression. This method proved to be efficient for deriving a unique system of weights which allowed to estimate in an efficient way and simultaneously many study parameters. Applications on real and simulated survey data showed its high efficiency. This …
The Impact of Barriers on Export Behavior of a Developing Country Firms: Evidence from Tanzania
2012
The purpose of this paper is to identify main export barriers and to test empirically their impact on export behavior. A survey of 122 manufacturing firms was conducted in Tanzania between October 2008 and February 2009. The survey data were analyzed using factor analysis and the Tobit regression model. Factor analysis identified five significant barrier factors: lack of export market knowledge and information, export supply capacity constraints, inadequate export financing, inefficient regulatory framework, and poor infrastructure. The impact of the barriers on export behavior was then tested using the Tobit regression model. The results of the Tobit estimation indicated that the lack of e…
Inclusive educational practices as perceived by prospective special education teachers in Estonia, Finland, and the United States.
1997
A survey of 125 prospective special education teachers assessed perceptions and beliefs about inclusive education in Estonia, Finland, and the United States (Michigan). The attitudes toward inclusion were rather critical. The Estonians were the most critical group, the Finns the least critical. The meanings attached to a student with severe mental retardation were related to the educational setting assessed as the best for this student. The findings suggest that special educators perceptions about inclusion are related to the prevailing implementation of inclusive education. The results support also the idea that the meanings attached to a person with a disability are connected with behavio…
Criminal networks analysis in missing data scenarios through graph distances
2021
Data collected in criminal investigations may suffer from issues like: (i) incompleteness, due to the covert nature of criminal organizations; (ii) incorrectness, caused by either unintentional data collection errors or intentional deception by criminals; (iii) inconsistency, when the same information is collected into law enforcement databases multiple times, or in different formats. In this paper we analyze nine real criminal networks of different nature (i.e., Mafia networks, criminal street gangs and terrorist organizations) in order to quantify the impact of incomplete data, and to determine which network type is most affected by it. The networks are firstly pruned using two specific m…