Pomiar efektywności banków w Polsce z wykorzystaniem stochastycznej analizy granicznej

The aim of the paper was to estimate the level of efficiency of commercial banks operating in Poland. In order to do that, authors evaluated the level of development of the polish banking system and with the use of the parametric Stochastic Frontier Approach (SFA) the average inefficiency was estimated (for 34 banks between 2005 and 2011). The intermediation approach was applied to determine the inputs and outputs of banks. In the analyzed period the average efficiency level was increasing. Significant impact on technical efficiency had the financial crisis. Home field advantage hypothesis  and global advantage hypothesis were also verified. The crisis decreased efficiency. The work has the following structure: in the first part the characteristics of the polish banking system were presented. In the second part the authors showed the results of the most important works on efficiency for Polish banking sector, than the research method, data and results were presented. In the last part the most important conclusions were pointed out.Celem niniejszego opracowania jest określenie stopnia efektywności banków komercyjnych działających w Polsce. Autorzy dokonali oceny stopnia rozwoju sektora bankowego oraz wykorzystując parametryczny model stochastycznej analizy granicznej  (Stochastic Frontier Aproach - SFA) wyznaczyli średnie poziomy efektywności dla 34 banków działających w Polsce w latach 2005-2011. W opracowaniu przyjęto definicję banku działającego jako pośrednik finansowy , co pozwoliło na określenia nakładów i ich wyników. W badanym okresie zaobserwowano zwiększający się poziom efektywności banków komercyjnych w Polsce. Ponadto, zweryfikowano hipotezę dotyczącą wyższej efektywności banków z dominującym udziałem kapitału zagranicznego nad bankami z przewagą kapitału krajowego. Co więcej, zwrócono uwagę na istotny wpływ globalnego kryzysu finansowego na efektywność instytucji finansowych. W okresie 2008-2009  zaobserwowano znaczący spadek efektywności kosztowej większości banków

Metallic nanorings for broadband, enhanced extraction of light from solid-state emitters

We report on the increased extraction of light emitted by solid-state sources embedded within high refractive index materials. This is achieved by making use of a local lensing effect by sub-micron metallic rings deposited on the sample surface and centered around single emitters. We show enhancements in the intensity of the light emitted by InAs/GaAs single quantum dot lines into free space as high as a factor 20. Such a device is intrinsically broadband and therefore compatible with any kind of solid-state light source. We foresee the fabrication of metallic rings via scalable techniques, like nano-imprint, and their implementation to improve the emission of classical and quantum light from solid-state sources. Furthermore, while increasing the brightness of the devices, the metallic rings can also act as top contacts for the local application of electric fields for carrier injection or wavelength tuning.Comment: 10 pages, 3 figure

Optical sensing with Anderson-localised light

We show that fabrication imperfections in silicon nitride photonic crystal waveguides can be used as a resource to efficiently confine light in the Anderson-localised regime and add functionalities to photonic devices. Our results prove that disorder-induced localisation of light can be utilised to realise an alternative class of high-quality optical sensors operating at room temperature. We measure wavelength shifts of optical resonances as large as 15.2 nm, more than 100 times the spectral linewidth of 0.15\,nm, for a refractive index change of about 0.38. By studying the temperature dependence of the optical properties of the system, we report wavelength shifts of up to about 2 nm and increases of more than a factor 2 in the quality factor of the cavity resonances, when going from room to cryogenic temperatures. Such a device can allow simultaneous sensing of both local contaminants and temperature variations, monitored by tens of optical resonances spontaneously appearing along a single photonic crystal waveguide. Our findings demonstrate the potential of Anderson-localised light in photonic crystals for scalable and efficient optical sensors operating in the visible and near-infrared range of wavelengths.Comment: 10 pages, 3 figure

GaAs droplet quantum dots with nanometer-thin capping layer for plasmonic applications

We report on the growth and optical characterisation of droplet GaAs quantum dots with extremely-thin (11 nm) capping layers. To achieve such result, an internal thermal heating step is introduced during the growth and its role in the morphological properties of the quantum dots obtained is investigated via scanning electron and atomic force microscopy. Photoluminescence measurements at cryogenic temperatures show optically stable, sharp and bright emission from single quantum dots, at near-infrared wavelengths. Given the quality of their optical properties and the proximity to the surface, such emitters are ideal candidates for the investigation of near field effects, like the coupling to plasmonic modes, in order to strongly control the directionality of the emission and/or the spontaneous emission rate, crucial parameters for quantum photonic applications.Comment: 1 pages, 3 figure

Temporal Stabilisation of Flux Reconstruction on Linear Problems

Filtering is often used in Large Eddy Simulation with a global filter width, instead here a filter width in the reference domain of high order Flux Reconstruction is considered. It is shown via Von Neumann analysis how filtering effects the dispersion and dissipation of the scheme when spatially and temporally discretised. With it being shown that filtering stabilises the scheme temporally by upto $25\%$ for forth order FR. The impact of filtering on error production is calculated, highlighting the reduction in convective velocity caused and showing numerically the impact on order of accuracy. Finally, the turbulent Taylor-Green case is used to understand the effect of reference domain filtering on the transition to turbulence, and a filter Reynolds number is defined that is shown to be useful in understanding the effect of filtering on simulations.Comment: AIAA Aviation Forum June 201