Publications des institutions partenaires

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Acute appendicitis: prospective evaluation of a diagnostic algorithm integrating ultrasound and low-dose CT to reduce the need of standard CT.

To evaluate an algorithm integrating ultrasound and low-dose unenhanced CT with oral contrast medium (LDCT) in the assessment of acute appendicitis, to reduce the need of conventional CT.

Institution partenaire

Université de Genève

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English / 01/01/2011

Generalized monotone additive latent variable models

For manifest variables with additive noise and for a given number of latent variables with an assumed distribution, we propose to nonparametrically estimate the association between latent and manifest variables. Our estimation is a two step procedure: first it employs standard factor analysis to estimate the latent variables as theoretical quantiles of the assumed distribution;...

Institution partenaire

Université de Genève

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English / 01/01/2010

EuroCow, the Calibration and Orientation Workshop (Euro- pean Spatial Data Research)

This research presents methods for detecting and isolating faults in multiple Micro-Electro-Mechanical System (MEMS) Inertial Measurement Unit (IMU) configurations. Traditionally, in the inertial technology, the task Fault Detection and Isolation (FDI) is realized by the parity space method. However, this approach performs poorly with low-cost MEMS-IMUs, although, it provides...

Institution partenaire

Université de Genève

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English / 01/01/2010

Goodness-of-fit for Generalized Linear Latent Variables Models

Generalized Linear Latent Variables Models (GLLVM) enable the modeling of relationships between manifest and latent variables, where the manifest variables are distributed according to a distribution of the exponential family (e.g. binomial or normal) and to the multinomial distribution (for ordinal manifest variables). These models are widely used in social sciences. To test the...

Institution partenaire

Université de Genève

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English / 01/01/2010

Assessing multivariate predictors of financial market movements : a latent factor framework for ordinal data

Much of the trading activity in Equity markets is directed to brokerage houses. In exchange they provide so-called “soft dollars,” which basically are amounts spent in “research” for identifying profitable trading opportunities. Soft dollars represent about USD 1 out of every USD 10 paid in commissions. Obviously they are costly, and it is interesting for an institutional investor to...

Institution partenaire

Université de Genève

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English / 01/01/2009

A robust coefficient of determination for Regression

To assess the quality of the fit in a multiple linear regression, the coefficient of determination or R2 is a very simple tool, yet the most used by statistics users. It is well known that the classical (least-squares) fit and coefficient of determination can be arbitrary misleading in the presence of a single outlier. In many applied setting, the assumption of normality of the error...

Institution partenaire

Université de Genève

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English / 01/01/2009

Robust estimation of constrained covariance matrices for Confirmatory Factor Analysis

Confirmatory factor analysis (CFA) is a data analysis procedure that is widely used in social and behavioral sciences in general and other applied sciences that deal with large quantities of data (variables). The underlying model links a set latent factors, that are supposed to correspond to latent concepts, to a larger set of observed (manifest) variables through linear regression...

Institution partenaire

Université de Genève

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English / 01/01/2009

Zero-inflated Truncated Generalized Pareto Distribution for the Analysis of Radio Audience Data

Extreme value data with a high clump-at-zero occur in many domains. Moreover, it might happen that the observed data are either truncated below a given threshold and/or might not be reliable enough below that threshold because of the recording devices. This situations occurs in particular with radio audience data measured using personal meters that record environmental noise every...

Institution partenaire

Université de Genève

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English / 01/01/2009

Higher-order robustness

The higher–order robustness for M–estimators is introduced and defined. The conditions needed to ensure higher stability of the asymptotic bias are provided by refining the Von Mises bias expansion. Admissible M–estimators featuring second–order robustness are thus introduced. Then, a saddle-point argument is applied in order to approximate the finite sample distribution of second–...

Institution partenaire

Université de Genève

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English / 01/01/2009

Options pricing with realized volatility

We develop a discrete-time stochastic volatility option pricing model, which exploits the information contained in high-frequency data. The Realized Volatility (RV) is used as a proxy of the unobservable log-returns volatility. We model its dynamics by a simple but effective (pseudo) long memory process, the Heterogeneous Auto-Regressive Gamma with Leverage (HARGL) process. Both the...

Institution partenaire

Université de Genève

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English / 01/01/2009

A fully parametric approach to minimum power-divergence estimation

We approach parameter estimation based on power-divergence using Havrda-Charvat generalized entropy. Unlike other robust estimators relying on divergence measures, the procedure is fully parametric and avoids complications related to bandwidth selection. Hence, it allows for the treatment of multivariate distributions. The parameter estimator is indexed by a single constant q,...

Institution partenaire

Université de Genève

Full Text

English / 01/01/2009

The PsyCoLaus study: methodology and characteristics of the sample of a population-based survey on psychiatric disorders and their association with genetic and cardiovascular risk factors

Background The Psychiatric arm of the population-based CoLaus study (PsyCoLaus) is designed to: 1) establish the prevalence of threshold and subthreshold psychiatric syndromes in the 35 to 66 year-old population of the city of Lausanne (Switzerland); 2) test the validity of postulated definitions for subthreshold mood and anxiety syndromes; 3) determine the associations between...

Institution partenaire

Université de Genève

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English / 01/01/2009

Predicting House Prices with Spatial Dependence: Impacts of Alternative Submarket Definitions

We analyze the impacts of alternative submarket definitions when predicting house prices in a mass appraisal context, using both ordinary least squares (OLS) and geostatistical techniques. For this purpose, we use over 13,000 housing transactions for Louisville, Kentucky. We use districts defined by the local property tax assessment office as well as a classification of census tracts...

Institution partenaire

Université de Genève

Full Text

English / 01/01/2008

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