1,722,086 research outputs found
MINERAL RECOGNITION AND LIBERATION DEGREE MEASUREMENTS IN INDUSTRIAL ORE PROCESSING
Full text linkAims at identifying calculation procedures and representation methods for identifying the mineral species present in a rock. The goal of the study is to identify: the characteristic spectrum for each mineral species identified in the ore; the main shape of the individual species; the preferential arrangement of the individual mineral species; the grain-size distribution of the individual mineral species and of the grains resulting from comminution processes; the degree of liberation for each mineral; and the degree of liberation of the comminution products obtained from the ores. -Author
Unstable Diffusion Indexes: With an Application to Bond Risk Premia
Full text linkThis paper studies the empirically relevant problem of estimation and inference in diffusion index forecasting models with structural instability. Factor model and factor augmented regression both experience a structural change with different unknown break dates. In the factor model, we estimate factors and loadings by principal components. We consider least squares estimation of the factor augmented regression and propose a break test. The empirical application uncovers instabilities in the linkages between bond risk premia and macroeconomic factors.</p
Tail Risk Dynamics in Stock Returns: Links to the Macroeconomy and Global Markets Connectedness
Full text linkWe propose a new time-varying peaks over threshold model to study tail risk dynamics in equity markets: the laws of motion for the parameters are defined through the score-based approach. We apply the model to daily returns from U.S. size-sorted decile stock portfolios and show that large firms’ tail risk increases during recessions more than small firms’ tail risk. Our results are consistent with the granular hypothesis of aggregate fluctuations, and we quantify the impact of large firms’ tail risk shocks on the economy.A measure of tail connectedness is proposed: evidence from international equity markets shows that tail connectedness increases during periods of turmoil
Testing for Regime Changes in Portfolios with a Large Number of Assets: A Robust Approach to Factor Heteroskedasticity
No full textWe develop a new test for threshold-type regime changes in the risk exposures in portfolios with a large number of financial assets whose returns exhibit an approximate factor structure. Unlike existing procedures to detect discrete shifts in factor models, our test is robust to regime-specific second moment of the common factors. We rely on an auxiliary threshold regression: we take a weighted cross-sectional average of the cross-sectional units; we estimate the factors from the original model under the null hypothesis of no regime changes; we construct a Lagrange multiplier statistic to test for threshold effect in the auxiliary regression. Numerical results show the good finite sample properties of our procedure. The empirical analysis uncovers the dynamics of portfolio weights and diversification benefits in factor mimicking portfolios across different regimes
Least Squares Estimation of Large Dimensional Threshold Factor Models
Full text linkThis paper studies large dimensional factor models with threshold-type regime shifts in the loadings. We estimate the threshold by concentrated least squares, and factors and loadings by principal components. The estimator for the threshold is superconsistent, with convergence rate that depends on the time and cross-sectional dimensions of the panel, and it does not affect the estimator for factors and loadings: this has the same convergence rate as in linear factor models. We propose model selection criteria and a linearity test. Empirical application of the model shows that connectedness in financial variables increases during periods of high economic policy uncertainty
Predicting the Distribution of Stock Returns: Model Formulation, Statistical Evaluation, VaR Analysis and Economic Significance
No full textA Simple Test for Linearity Against Exponential Smooth Transition Models with Endogenous Variables
No full textSecurity in the Firefox OS and Tizen Mobile Platforms
No full textEmerging mobile platforms Firefox OS and Tizen are learning from Android's security successes and trying to avoid its limitations. Although these platforms offer largely novel solutions, they can still learn from one another. The Web extra at http://youtu.be/yZjVsWz_DAY is a video discussion in which authors Fabio Massacci and Yury Zhauniarovich discuss Android's successes and limitations and what developers can learn from them
Aspetti di sicurezza e igiene del lavoro nel comparto dell’estrazione e trasformazione dei materiali lapidei
No full textFormazione in materia di sicurezza e igiene del lavoro nei corsi di studi universitari di ingegneria dell’ambiente, del territorio e delle risorse
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