Dielectric resonances in disordered media

Binary disordered systems are usually obtained by mixing two ingredients in variable proportions: conductor and insulator, or conductor and super-conductor. and are naturally modeled by regular bi-dimensional or tri-dimensional lattices, on which sites or bonds are chosen randomly with given probabilities. In this article, we calculate the impedance of the composite by two independent methods: the so-called spectral method, which diagonalises Kirchhoff's Laws via a Green function formalism, and the Exact Numerical Renormalization method (ENR). These methods are applied to mixtures of resistors and capacitors (R-C systems), simulating e.g. ionic conductor-insulator systems, and to composites consituted of resistive inductances and capacitors (LR-C systems), representing metal inclusions in a dielectric bulk. The frequency dependent impedances of the latter composites present very intricate structures in the vicinity of the percolation threshold. We analyse the LR-C behavior of compounds formed by the inclusion of small conducting clusters (``$n$-legged animals'') in a dielectric medium. We investigate in particular their absorption spectra who present a pattern of sharp lines at very specific frequencies of the incident electromagnetic field, the goal being to identify the signature of each animal. This enables us to make suggestions of how to build compounds with specific absorption or transmission properties in a given frequency domain.Comment: 10 pages, 6 figures, LaTeX document class EP

Thermal Glass Stress Analysis – Design Considerations

The use of glass in windows and curtain walls, in residential as well as in high-rise buildings, is something that requires great care in design and execution. Apart from complying with typical structural engineering practices and ensuring, for example, that the glass thickness is sufficient to withstand wind loads, impact loads etc. it is necessary always also to consider the thermal-stress resistance of the glass employed as well as the temperature distribution across glass and façade components. This topic is not new as it began to be analysed with the emergence of the first body tinted basic glass types. All the analysis done today is based on a linear approach and a more or less simplified algorithm. But modern constructions make it necessary to recognize special details and to acquire a more detailed view of the construction and use of such windows and curtain walls. Glass manufacturers can assist in this by helping to analyse the thermal stress characteristics but also the temperature distribution in different constructions. It is necessary here also to evaluate the different boundary conditions, which vary from location to location. The paper will begin by describing the basic methods for analysing the thermal-stress resistance of glazing units. But it will then go on to show the influence of the boundary conditions on the final result. The paper will also show the effect of a detailed 2D FE analysis in specifically analysing critical locations in curtain walls, such as shadow boxes or spandrel areas

Elastic X-ray scattering from state-selected molecules

International audienceThe characterization of electronic, vibrational, and rotational states using elastic (coherent) X-ray scattering is considered. The scattering is calculated directly from complete active space self-consistent field level ab initio wavefunctions for H-2 molecules in the ground-state X-1 Sigma(+)(g) and first-excited EF1 Sigma(+)(g) electronic states. The calculated scattering is compared to recent experimental measurements [Y.-W. Liu et al., Phys. Rev. A 89, 014502 (2014)], and the influence of vibrational and rotational states on the observed signal is examined. The scaling of the scattering calculations with basis set is quantified, and it is found that energy convergence of the ab initio calculations is a good indicator of the quality of the scattering calculations. Published by AIP Publishing

Combined network intrusion and phasor data anomaly detection for secure dynamic control centers

The dynamic operation of power transmission systems requires the acquisition of reliable and accurate measurement and state information. The use of TCP/IP-based communication protocols such as IEEE C37.118 or IEC 61850 introduces different gateways to launch cyber-attacks and to compromise major system operation functionalities. Within this study, a combined network intrusion and phasor data anomaly detection system is proposed to enable a secure system operation in the presence of cyber-attacks for dynamic control centers. This includes the utilization of expert-rules, one-class classifiers, as well as recurrent neural networks to monitor different network packet and measurement information. The effectiveness of the proposed network intrusion and phasor data anomaly detection system is shown within a real-time simulation testbed considering multiple operation and cyber-attack conditions

Measuring the impact of learning at the workplace on organisational performance

Purpose: The purpose of this article is to explore the importance of workplace learning in the context of performance measurement on an organisational level. It shows how workplace learning analytics can be grounded on professional identity transformation theory and integrated into performance measurement approaches to understand its organisation-wide impact. Design/methodology/approach: In a conceptual approach, a framework to measure the organisation-wide impact of workplace learning interventions has been developed. As a basis for the description of the framework, related research on relevant concepts in the field of performance measurement approaches, workplace learning, professional identity transformation, workplace and social learning analytics are discussed. A case study in a European Public Employment Service is presented. The framework is validated by qualitative evaluation data from three case studies. Finally, theoretical as well as practical implications are discussed. Findings: Professional identity transformation theory provides a suitable theoretical framework to gain new insights into various dimensions of workplace learning. Workplace learning analytics can reasonably be combined with classical performance management approaches to demonstrate its organisation-wide impact. A holistic and streamlined framework is perceived as beneficial by practitioners from several European Public Employment Services. Research limitations/implications: Empirical data originates from three case studies in the non-profit sector only. The presented framework needs to be further evaluated in different organisations and settings. Practical implications: The presented framework enables non-profit organisations to integrate workplace learning analytics in their organisation-wide performance measurement, which raises awareness for the importance of social learning at the workplace. Originality/value: The paper enriches the scarce research base about workplace learning analytics and its potential links to organisation-wide performance measurement approaches. In contrast to most previous literature, a thorough conceptualisation of workplace learning as a process of professional identity transformation is used

Plasma-MDS, a metadata schema for plasma science with examples from plasma technology

A metadata schema, named Plasma-MDS, is introduced to support research data management in plasma science. Plasma-MDS is suitable to facilitate the publication of research data following the FAIR principles in domain-specific repositories and with this the reuse of research data for data driven plasma science. In accordance with common features in plasma science and technology, the metadata schema bases on the concept to separately describe the source generating the plasma, the medium in which the plasma is operated in, the target the plasma is acting on, and the diagnostics used for investigation of the process under consideration. These four basic schema elements are supplemented by a schema element with various attributes for description of the resources, i.e. the digital data obtained by the applied diagnostic procedures. The metadata schema is first applied for the annotation of datasets published in INPTDAT -- the interdisciplinary data platform for plasma technology.Comment: 15 pages, 1 figure, 10 table