The safest dependence structure among risks.

In this paper, we investigate the dependence in Frechet spaces containing mutually exclusive risks. It is shown that, under some reasonable assumptions, the safest dependence structure, in the sense of the minimal stop-loss premiums for the aggregate claims involved, is obtained with the Frechet lower bound and precisely corresponds to the mutually exclusive risk of the Frechet space. In that respect, the present paper complements some previous studies by Heilmann (1986), Dhaene & Goovaerts (1996, 1997), Müller (1997) and Taizhong & Zhiqiang (1998). A couple of actuarial applications enhance the interest of the results derived.Dependence; Risk; Structure;

Comovements of Returns and Volatility in International Stock Markets: A High-Frequency Approach

This paper analyzes common factors in the continuous volatility component, co-extreme and co-jump behavior of a sample of stock market indices. In order to identify those components in stock price processes during a trading day we use high-frequency data and techniques. We show that in most of the cases one common factor is enough to describe the largest part of the international variation in the continuous part of volatility and that this factor's importance has increased over time. Furthermore, we find strong evidence for asymmetries between extremely negative and positive co-extreme close-open returns and of negative and positive co-jumps across countries..Volatility, realized volatility, high-frequency, comovements, cojumps

A multicriteria analysis of stated preferences among freight transport alternatives

Stated preferences data can be of different types: choice data, rankings or ratings. In all cases, these data can be used in different ways as inputs of econometric discrete choice models. This allows to estimate the weights of the different attributes characterizing an alternative. For freight transport, an alternative's attributes would be, for example, reliability, safety, frequency, etc., besides time and cost. Depending on the data sample, number of alternatives and number of attributes, it is possible to proceed to an analysis of individual data or of aggregated data. In case one is interested to analyze individual behaviors in depth, the option exists to rely on some kind of multicriteria analysis for deriving individual utility functions (actually, decision functions) rather than on a classic discrete choice model. Such a procedure also can be useful for deriving individual utilities as input in a hybrid model combining individual utilities with group data. Such a multicriteria approach is envisaged in the context of a stated preference experiment that is currently applied to freight shippers in Belgium. The data in this case are rankings of alternatives, and there is multicritera method that is particularly well adapted for such data: the UTA models developed by Jacquet-Lagrèze and Siskos. It is based on the specification of an additive utility made of non-linear partial utility functions that are piecewise linear. This allows the convenient set-up of a linear goal programming problem which estimates all the functions and their weights. The paper intends to present the ranking experiment, and to use some of the preliminary interviews to illustrate this UTA methodology. Also, it will be shown how it can be used to derive equivalent money values for each attributes on the basis of the cost attribute, and how to distinguish valuations in terms of willingness to pay and willingness to accept a compensation.

Optical tracing of multiple charges in single-electron devices

Single molecules that exhibit narrow optical transitions at cryogenic temperatures can be used as local electric-field sensors. We derive the single charge sensitivity of aromatic organic dye molecules, based on first principles. Through numerical modeling, we demonstrate that by using currently available technologies it is possible to optically detect charging events in a granular network with a sensitivity better than $10^{-5}e/\sqrt{\textrm{Hz}}$ and track positions of multiple electrons, simultaneously, with nanometer spatial resolution. Our results pave the way for minimally-invasive optical inspection of electronic and spintronic nanodevices and building hybrid optoelectronic interfaces that function at both single-photon and single-electron levels.Comment: 7 pages, submitted to Physical Revie

Parental expectations of maternal and child health services

This article reports on survey research (N=1,418) aimed at examining whether parental expectations of maternal and child health (MCH) services are influenced by group characteristics (e.g., socioeconomic status [SES], ethnicity, at risk of poverty) and/or individual parenting context variables (e.g., received social support) in a context where these services are available to all. The findings reveal that parents have different expectations about the technical and relational expertise of MCH nurses. However, the authors found only very weak associations between family characteristics and parental expectations, suggesting that individual differences matter more than SES and other more traditional distinctions. Implications for MCH services are made

3D Simulation with virtual stereo rig for optimizing centrifugal fertilizer spreading

Stereovision can be used to characterize of the fertilizer centrifugal spreading process and to control the spreading fertilizer distribution pattern on the ground reference. Fertilizer grains, however, resemble each other and the grain images contain little information on texture. Therefore, the accuracy of stereo matching algorithms in literature cannot be used as a reference for stereo images of fertilizer grains. In order to evaluate stereo matching algorithms applied to images of grains a generator of synthetic stereo particle images is presented in this paper. The particle stereo image generator consists of two main parts: the particle 3D position generator and the virtual stereo rig. The particle 3D position generator uses a simple ballistic flight model and the disc characteristics to simulate the ejection and the displacement of grains. The virtual stereo rig simUlates the stereo acquisition system and generates stereo images, a disparity map and an occlusion map. The results are satisfying and present an accurate reference to evaluate stereo particles matching algorithms

Risk and saving contracts.

Abstract: Following the ''time-capital'' approach of De Vylder (1997) it is shown that a fair life insurance contract can uniquely be separated into a fair savings and a fair pure risk contract. It is also shown that a fair life insurance contract can be separated into a fair associated stochastic savings contract and a fair associated pure risk contract.Risk;