214 research outputs found

    Boundaries of Disk-like Self-affine Tiles

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    Let T:=T(A,D)T:= T(A, {\mathcal D}) be a disk-like self-affine tile generated by an integral expanding matrix AA and a consecutive collinear digit set D{\mathcal D}, and let f(x)=x2+px+qf(x)=x^{2}+px+q be the characteristic polynomial of AA. In the paper, we identify the boundary T\partial T with a sofic system by constructing a neighbor graph and derive equivalent conditions for the pair (A,D)(A,{\mathcal D}) to be a number system. Moreover, by using the graph-directed construction and a device of pseudo-norm ω\omega, we find the generalized Hausdorff dimension dimHω(T)=2logρ(M)/logq\dim_H^{\omega} (\partial T)=2\log \rho(M)/\log |q| where ρ(M)\rho(M) is the spectral radius of certain contact matrix MM. Especially, when AA is a similarity, we obtain the standard Hausdorff dimension dimH(T)=2logρ/logq\dim_H (\partial T)=2\log \rho/\log |q| where ρ\rho is the largest positive zero of the cubic polynomial x3(p1)x2(qp)xqx^{3}-(|p|-1)x^{2}-(|q|-|p|)x-|q|, which is simpler than the known result.Comment: 26 pages, 11 figure

    System Level Simulation of Servo Accelerometer in Simulink

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    143-150This paper describes the derivation of a detailed model of a forced balance (servo) accelerometer and its implementation in a commercial MATLAB package. The sensing element is modeled at a system level, the control and interface electronics at a component level. The MATLAB simulation tool, SIMULINK allows very realistic insight into the system behavior. A shaketable model is made with the help of SIMMECHANICS tool. The accelerometer model is mounted on the shaketable and the system is connected to VIRTUAL REALITY tool to show the actual working of the system dynamically at the run time. The amplitude results with respect to frequency ratio have been plotted for various input forms and their implications have been studied

    Fog computing security: a review of current applications and security solutions

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    Fog computing is a new paradigm that extends the Cloud platform model by providing computing resources on the edges of a network. It can be described as a cloud-like platform having similar data, computation, storage and application services, but is fundamentally different in that it is decentralized. In addition, Fog systems are capable of processing large amounts of data locally, operate on-premise, are fully portable, and can be installed on heterogeneous hardware. These features make the Fog platform highly suitable for time and location-sensitive applications. For example, Internet of Things (IoT) devices are required to quickly process a large amount of data. This wide range of functionality driven applications intensifies many security issues regarding data, virtualization, segregation, network, malware and monitoring. This paper surveys existing literature on Fog computing applications to identify common security gaps. Similar technologies like Edge computing, Cloudlets and Micro-data centres have also been included to provide a holistic review process. The majority of Fog applications are motivated by the desire for functionality and end-user requirements, while the security aspects are often ignored or considered as an afterthought. This paper also determines the impact of those security issues and possible solutions, providing future security-relevant directions to those responsible for designing, developing, and maintaining Fog systems

    Flexibility in the Market for International Carbon Credits and Price Dynamics Difference with European Allowances

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    We analyze the price dynamics of European allowances and international carbon credits in the second phase of the European carbon market. We develop and use a model combining fundamental drivers associated with the demand for quotas by installations and risk-return considerations related to the financial nature of carbon permits. We estimate it with autoregressive conditional heteroskedasticity models. Although carbon permits present some characteristics of financial assets, we find that an increased volatility is not associated with an increased return. The price of allowances and credits are explained by similar factors. However, whereas the corresponding returns present comparable dynamics, the long-term relationships between the price of these two types of permits and their drivers differ significantly. While the price of allowances is demand-driven, we suggest the existence of a supply-side effect for credits, and explain it by the flexibility in the related market. The impact of the European economic activity is less visible on credits than on allowances. The price elasticity of allowances with regards to the coal and gas prices is negative in time periods of low economic activity while it is positive in the rest of the time. We suggest an explanation for this dynamics difference

    Hydrometeorological, glaciological and geospatial research data from the Peyto Glacier Research Basin in the Canadian Rockies

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    Canada First Research Excellent Fund’s Global Water Futures Programme, the National Sciences and Engineering Research Council of Canada’s Changing Cold Regions Network and Discovery Grants programme, the Canada Foundation for Innovation’s Canadian Rockies Hydrological Observatory, the Canada Research Chairs and Canada Excellence Research Chairs programmes, the Canadian Foundation for Climate and Atmospheric Sciences IP3 and WC2N networks, Natural Resources Canada, Environment Canada, Columbia Basin Trust, BC HydroPeer ReviewedThis paper presents hydrometeorological, glaciological and geospatial data from the Peyto Glacier Research Basin (PGRB) in the Canadian Rockies. Peyto Glacier has been of interest to glaciological and hydrological researchers since the 1960s, when it was chosen as one of five glacier basins in Canada for the study of mass and water balance during the International Hydrological Decade (IHD, 1965–1974). Intensive studies of the glacier and observations of the glacier mass balance continued after the IHD, when the initial seasonal meteorological stations were discontinued, then restarted as continuous stations in the late 1980s. The corresponding hydrometric observations were discontinued in 1977 and restarted in 2013. Datasets presented in this paper include high-resolution, co-registered digital elevation models (DEMs) derived from original air photos and lidar surveys; hourly off-glacier meteorological data recorded from 1987 to the present; precipitation data from the nearby Bow Summit weather station; and long-term hydrological and glaciological model forcing datasets derived from bias-corrected reanalysis products. These data are crucial for studying climate change and variability in the basin and understanding the hydrological responses of the basin to both glacier and climate change. The comprehensive dataset for the PGRB is a valuable and exceptionally long-standing testament to the impacts of climate change on the cryosphere in the high-mountain environment. The dataset is publicly available from Federated Research Data Repository at https://doi.org/10.20383/101.0259 (Pradhananga et al., 2020)

    Development of an In Vitro Model for the Multi-Parametric Quantification of the Cellular Interactions between Candida Yeasts and Phagocytes

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    We developed a new in vitro model for a multi-parameter characterization of the time course interaction of Candida fungal cells with J774 murine macrophages and human neutrophils, based on the use of combined microscopy, fluorometry, flow cytometry and viability assays. Using fluorochromes specific to phagocytes and yeasts, we could accurately quantify various parameters simultaneously in a single infection experiment: at the individual cell level, we measured the association of phagocytes to fungal cells and phagocyte survival, and monitored in parallel the overall phagocytosis process by measuring the part of ingested fungal cells among the total fungal biomass that changed over time. Candida albicans, C. glabrata, and C. lusitaniae were used as a proof of concept: they exhibited species-specific differences in their association rate with phagocytes. The fungal biomass uptaken by the phagocytes differed significantly according to the Candida species. The measure of the survival of fungal and immune cells during the interaction showed that C. albicans was the more aggressive yeast in vitro, destroying the vast majority of the phagocytes within five hours. All three species of Candida were able to survive and to escape macrophage phagocytosis either by the intraphagocytic yeast-to-hyphae transition (C. albicans) and the fungal cell multiplication until phagocytes burst (C. glabrata, C. lusitaniae), or by the avoidance of phagocytosis (C. lusitaniae). We demonstrated that our model was sensitive enough to quantify small variations of the parameters of the interaction. The method has been conceived to be amenable to the high-throughput screening of mutants in order to unravel the molecular mechanisms involved in the interaction between yeasts and host phagocytes
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