Craig's XY distribution and the statistics of Lagrangian power in two-dimensional turbulence

We examine the probability distribution function (PDF) of the energy injection rate (power) in numerical simulations of stationary two-dimensional (2D) turbulence in the Lagrangian frame. The simulation is designed to mimic an electromagnetically driven fluid layer, a well-documented system for generating 2D turbulence in the laboratory. In our simulations, the forcing and velocity fields are close to Gaussian. On the other hand, the measured PDF of injected power is very sharply peaked at zero, suggestive of a singularity there, with tails which are exponential but asymmetric. Large positive fluctuations are more probable than large negative fluctuations. It is this asymmetry of the tails which leads to a net positive mean value for the energy input despite the most probable value being zero. The main features of the power distribution are well described by Craig's XY distribution for the PDF of the product of two correlated normal variables. We show that the power distribution should exhibit a logarithmic singularity at zero and decay exponentially for large absolute values of the power. We calculate the asymptotic behavior and express the asymmetry of the tails in terms of the correlation coefficient of the force and velocity. We compare the measured PDFs with the theoretical calculations and briefly discuss how the power PDF might change with other forcing mechanisms

Which governs - the relationship or the contract?

According to the transaction cost economics literature, a firm’s external contractual relationships must be ‘fit for purpose’. What is a ‘fit for purpose’ contractual relationship should not be a normative decision, but an objective one, to be made with regard to achieving transaction cost efficiency, while defending the core competencies of the firm. Data from a Hong Kong case study is used to examine whether or not the client’s choice of contractual relationship is ‘fit for purpose’ and also to evaluate the impact of such a choice. The findings suggest that maintaining a relationship of high quality as a strategic policy not only reduces recourse to the contract but, also improves the quality and predictability of project performance and, is an antidote to ill-aligned contractual elements. These findings lend support to the growing trend towards relationship or relational contracting in construction

La substitution induced linear temperature dependence of electrical resistivity and Kondo behavior in the alloys, Ce_{2-x}La_{x}CoSi_{3}

The results of electrical resistivity, heat capacity and magnetic susceptibility behavior of new class of alloys, Ce_{2-x}La_{x}CoSi_{3}, are reported. The x= 0.0 alloy is mixed valent and La substitution for Ce (x= 0.25) induces linear temperature dependence of resistivity at low temperatures, an observation of relevance to the topic of non-Fermi liquid behavior. The modifications of Kondo effect for all the alloys are also presented.Comment: Accepted for publication in Solid State Communication

An Efficient Secure Multimodal Biometric Fusion Using Palmprint and Face Image

Biometrics based personal identification is regarded as an effective method for automatically recognizing, with a high confidence a person’s identity. A multimodal biometric systems consolidate the evidence presented by multiple biometric sources and typically better recognition performance compare to system based on a single biometric modality. This paper proposes an authentication method for a multimodal biometric system identification using two traits i.e. face and palmprint. The proposed system is designed for application where the training data contains a face and palmprint. Integrating the palmprint and face features increases robustness of the person authentication. The final decision is made by fusion at matching score level architecture in which features vectors are created independently for query measures and are then compared to the enrolment template, which are stored during database preparation. Multimodal biometric system is developed through fusion of face and palmprint recognition