Frequency and Severity Modelling Using Multifractal Processes: An Application to Tornado Occurrence in the USA and CAT Bonds

This paper proposes a statistical model for insurance claims arising from climatic events, such as tornadoes in the USA, that exhibit a large variability both in frequency and intensity. To represent this variability and seasonality, the claims process modelled by a Poisson process of intensity equal to the product of a periodic function, and a multifractal process is proposed. The size of claims is modelled in a similar way, with gamma random variables. This method is shown to enable simulation of the peak times of damage. A two-dimensional multifractal model is also investigated. The work concludes with an analysis of the impact of the model on the yield of weather bonds linked to damage caused by tornadoes.     

Effect of Accelerated Weathering on Biocomposites Processed by SMC and Compression Molding

The durability of biocomposites utilized for building components has been a subject of recent concern and questioning. To address these concerns, the long-term effects of weathering on biocomposites used as building components were evaluated using an accelerated weatherometer. The biocomposite samples were processed by sheet molding compounding (SMC) panel processing and/or compression molding. The accelerated weatherometer served to expose the samples to ultraviolet radiation (UV), condensation, and water spray at levels pertinent to actual conditions: 48 cycles of UV (340 nm) treatment at 60 °C for 2.5 h was followed by water spray for 0.5 h, and then condensation at 45 °C for 24 h. Twelve cycles were repeated in each test, and the total duration for the complete test was 2016 h. Measurements for color, surface roughness test weight change, and dynamical mechanical analysis were taken at regular intervals of time. It was found that the surface roughness increased, as the color changed, and storage modulus decreased with increases in the exposure time of the samples to accelerated weathering conditions, compared to their properties at the beginning of the test.