Emergency Messaging to General Public via Public Wireless Networks

Warnings to the broad population in an emergency situation, irrespective of location and condition, is a public policy responsibility. Public wireless networks offer now the opportunity to deliver emergency warnings in this way with explanations, because in many countries the mobile penetration rates are higher than any other access form .The paper summarizes the analysis of the selection process between Short messaging services (SMS) and Cell Broadcast messaging in the context of Denmark based on end user requirements and stakeholder roles. It demonstrates the many technical, cost-benefit and other trade-offs needed in supporting the population now with a dependable and wide-spread technology.SMS;cell broadcast (CB);emergency warnings;public wireless networks

Substrate influence on the plasmonic response of clusters of spherical nanoparticles

The plasmonic response of nanoparticles is exploited in many subfields of science and engineering to enhance optical signals associated with probes of nanoscale and subnanoscale entities. We develop a numerical algorithm based on previous theoretical work that addresses the influence of a substrate on the plasmonic response of collections of nanoparticles of spherical shape. Our method is a real space approach within the quasi-static limit that can be applied to a wide range of structures. We illustrate the role of the substrate through numerical calculations that explore single nanospheres and nanosphere dimers fabricated from either a Drude model metal or from silver on dielectric substrates, and from dielectric spheres on silver substrates.Comment: 12 pages, 13 figure

Fear and its implications for stock markets

The value of stocks, indices and other assets, are examples of stochastic processes with unpredictable dynamics. In this paper, we discuss asymmetries in short term price movements that can not be associated with a long term positive trend. These empirical asymmetries predict that stock index drops are more common on a relatively short time scale than the corresponding raises. We present several empirical examples of such asymmetries. Furthermore, a simple model featuring occasional short periods of synchronized dropping prices for all stocks constituting the index is introduced with the aim of explaining these facts. The collective negative price movements are imagined triggered by external factors in our society, as well as internal to the economy, that create fear of the future among investors. This is parameterized by a ``fear factor'' defining the frequency of synchronized events. It is demonstrated that such a simple fear factor model can reproduce several empirical facts concerning index asymmetries. It is also pointed out that in its simplest form, the model has certain shortcomings.Comment: 5 pages, 5 figures. Submitted to the Proceedings of Applications of Physics in Financial Analysis 5, Turin 200

Synchronization Model for Stock Market Asymmetry

The waiting time needed for a stock market index to undergo a given percentage change in its value is found to have an up-down asymmetry, which, surprisingly, is not observed for the individual stocks composing that index. To explain this, we introduce a market model consisting of randomly fluctuating stocks that occasionally synchronize their short term draw-downs. These synchronous events are parameterized by a ``fear factor'', that reflects the occurrence of dramatic external events which affect the financial market.Comment: 4 pages, 4 figure

Emergency Messaging to General Public via Public Wireless Networks

Warnings to the broad population in an emergency situation, irrespective of location and condition, is a public policy responsibility. Public wireless networks offer now the opportunity to deliver emergency warnings in this way with explanations, because in many countries the mobile penetration rates are higher than any other access form .The paper summarizes the analysis of the selection process between Short messaging services (SMS) and Cell Broadcast messaging in the context of Denmark based on end user requirements and stakeholder roles. It demonstrates the many technical, cost-benefit and other trade-offs needed in supporting the population now with a dependable and wide-spread technology

Impact of Small Group Size on Neighborhood Influences in Multilevel Models

Objective: Although there is a growing body of literature on sample size in multilevel or hierarchical modeling, few studies have examined the impact of group sizeMultilevel, Neighborhood, Body Weight, Obesity, Sample Size

Design of one-dimensional Lambertian diffusers of light

We describe a method for designing a one-dimensional random surface that acts as a Lambertian diffuser. The method is tested by means of rigorous computer simulations and is shown to yield the desired scattering pattern.Comment: 6 pages, 2 figure

Experimental investigation of cut-off phenomena in non-linear photonic crystal fibers

The modal cut-off is investigated experimentally in a series of high quality non-linear photonic crystal fibers. We demonstrate a suitable measurement technique to determine the cut-off wavelength and verify it by inspecting the near field of the modes that may be excited below and above the cut-off. We observe a double peak structure in the cut-off spectra, which is attributed to a splitting of the higher order modes. The cut-off is measured for seven different fiber geometries with different pitches and relative hole size, and a very good agreement with recent theoretical work is found.Comment: 3 pages including 1 table and 4 figures. Accepted for Optics Letter