Phase space monitoring of exciton-polariton multistability

Dynamics of exciton-polariton multistability is theoretically investigated. Phase portraits are used as a tool to enlighten the microscopic phenomena which influence spin multistability of a confined polariton field as well as ultrafast reversible spin switching. The formation of a non-radiative reservoir, due to polariton pairing into biexcitons is found to play the lead role in the previously reported spin switching experiments. Ways to tailor this reservoir formation are discussed in order to obtain optimal spin switching reliability

Menger curvature and rectifiability

For a Borel set E in R^n, the total Menger curvature of E, or c(E), is the integral over E^3 (with respect to 1-dimensional Hausdorff measure in each factor of E) of c(x,y,z)^2, where 1/c(x,y,z) is the radius of the circle passing through three points x, y, and z in E. Let H^1(X) denote the 1-dimensional Hausdorff measure of a set X. A Borel set E in R^n is purely unrectifiable if for any Lipschitz function gamma from R to R^n, H^1(E cap gamma(R)) = 0. It is said to be rectifiable if there exists a countable family of Lipschitz functions gamma_i from R to R^n such that H^1(E - union gamma_i(R)) = 0. It may be seen from this definition that any 1-set E (that is, E Borel and 0<H^1(E)<\infty) can be decomposed into two disjoint subsets E_irr and E_rect, where E_irr is purely unrectifiable and E_rect is rectifiable. Theorem. If E is a 1-set in R^n and c(E)^2 is finite, then E is rectifiable.Comment: 39 pages, 3 figures, published version, abstract added in migratio

Intellectual Property Rights and Innovation in Developing Countries: Evidence from Panel Data

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Intellectual Property Rights and Innovation around the World: Evidence from Panel Data

This article contributes to the literature on innovation and development by identifying the determinants of innovation, and the role of intellectual property rights, in industrialized and developing countries. Controlling for sample selection, I find that, in general, the level of intellectual property protection and a country's technological capital stock are positively related to research and development investments, while openness to trade has a negative effect. I also find the determinants of innovation to be different for industrialized and developing countries. This is supported by endogeneity tests showing that intellectual property protection is endogenous in industrialized countries, but not in developing countries. However, in both sub-samples, research and development investments Granger-cause intellectual property protection levels, whereas surprisingly, intellectual property protection does not Granger-cause research and development investments.Innovation, intellectual property rights, developing countries, panel data, selection model

Regression modeling for digital test of ΣΔ modulators

The cost of Analogue and Mixed-Signal circuit testing is an important bottleneck in the industry, due to timeconsuming verification of specifications that require state-ofthe- art Automatic Test Equipment. In this paper, we apply the concept of Alternate Test to achieve digital testing of converters. By training an ensemble of regression models that maps simple digital defect-oriented signatures onto Signal to Noise and Distortion Ratio (SNDR), an average error of 1:7% is achieved. Beyond the inference of functional metrics, we show that the approach can provide interesting diagnosis information.Ministerio de Educación y Ciencia TEC2007-68072/MICJunta de Andalucía TIC 5386, CT 30

Innovation Theories: Relevance and Implications for Developing Country Innovation

Innovation is at the basis of economic development and as such, it is instrumental for developing countries. We review the literature on innovation from the perspectives of four select branches of economics to build a conceptual framework of innovation applicable to developing countries. The conceptual framework includes insights from the surveyed literature and identifies areas of further research. Finally, we conclude with policy recommendations for innovation policies in developing countries highlighting the fact that intellectual property protection is not likely to be at the basis of innovation in these countries.Innovation, Development, Absorptive Capacity

Quality criteria benchmark for hyperspectral imagery

Hyperspectral data appear to be of a growing interest over the past few years. However, applications for hyperspectral data are still in their infancy as handling the significant size of the data presents a challenge for the user community. Efficient compression techniques are required, and lossy compression, specifically, will have a role to play, provided its impact on remote sensing applications remains insignificant. To assess the data quality, suitable distortion measures relevant to end-user applications are required. Quality criteria are also of a major interest for the conception and development of new sensors to define their requirements and specifications. This paper proposes a method to evaluate quality criteria in the context of hyperspectral images. The purpose is to provide quality criteria relevant to the impact of degradations on several classification applications. Different quality criteria are considered. Some are traditionnally used in image and video coding and are adapted here to hyperspectral images. Others are specific to hyperspectral data.We also propose the adaptation of two advanced criteria in the presence of different simulated degradations on AVIRIS hyperspectral images. Finally, five criteria are selected to give an accurate representation of the nature and the level of the degradation affecting hyperspectral data

Saturated hydraulic conductivity determined by on ground mono-offset Ground-Penetrating Radar inside a single ring infiltrometer

In this study we show how to use GPR data acquired along the infiltration of water inside a single ring infiltrometer to inverse the saturated hydraulic conductivity. We used Hydrus-1D to simulate the water infiltration. We generated water content profiles at each time step of infiltration, based on a particular value of the saturated hydraulic conductivity, knowing the other van Genuchten parameters. Water content profiles were converted to dielectric permittivity profiles using the Complex Refractive Index Method relation. We then used the GprMax suite of programs to generate radargrams and to follow the wetting front using arrival time of electromagnetic waves recorded by a Ground-Penetrating Radar (GPR). Theoretically, the 1D time convolution between reflectivity and GPR signal at any infiltration time step is related to the peak of the reflected amplitude recorded in the corresponding trace in the radargram. We used this relation ship to invert the saturated hydraulic conductivity for constant and falling head infiltrations. We present our method on synthetic examples and on two experiments carried out on sand soil. We further discuss on the uncertainties on the retrieved saturated hydraulic conductivity computed by our algorithm from the van Genuchten parameters