Fast Data Retrieval and Enhanced Data Security of Cloud Storage in Luby Transform

AbstractCloud computing is a set of IT services that are provided to a customer over a network on a leased basis and with the ability to scale up or down their service requirements. It advantages to mention but a few include scalability, resilience, flexibility, efficiency and outsourcing non-core activities.Despite the potential gains achieved from the cloud computing, the organizations are slow in accepting it due to security issues and challenges associated with it. The idea of handing over important data to another company is worrisome; such that the consumers need to be vigilant in understanding the risks of data breaches in this new environment. This paper introduces analysis of the cloud computing security issues and challenges focusing on providing data confidentiality along with high requirement of data availability in cloud technology

A Game Theoretic Approach to Modelling Jamming Attacks in Delay Tolerant Networks

Cyberspace plays a prominent role in our social, economic and civic welfare and cyber security issues are of paramount importance today. Growing reliance of the intertwined military and civilian applications on wireless computer networks makes these networks highly vulnerable to attacks of which jamming attacks are a vital and exigent problem. In this paper, we study defence against jamming attacks as game in a delay tolerant network, with two adversarial players: the jammer playing against the transmitter. The transmitters seek to choose an optimal time to schedule his transmission securely, so as to maximize the probability of successful delivery before his session expires, while these transmissions are subject to inference from the jammer, who attempts to minimize this probability . We design strategies for the transmitters that offset transmission period based inference of network traffic by the jammer. We model these interactions and decisions as a game and use simulation as a tool to evaluate the games. Probability distribution functions over finite set of strategies are proposed to compute the expected payoff of both the players. Simulation results are used to evaluate the expected payoff along with the resulting equilibrium in cases where players are biased and unbiased. These results are used to strategically decide on the optimal time for both the players, and evaluate the efficiency of the strategies used by the transmitters against jammer attacks.

Entrecruzamiento de un almidón comercial cubano para su uso como matriz de liberación controlada de fármacos

Se estudió el entrecruzamiento de un almidón comercial cubano con epiclorhidrina (ECH) y los productos se evaluaron con vistas a la liberación controlada de fármacos. Inicialmente, se determinó el tiempo de gelatinización y posteriormente, se investigó el entrecruzamiento, estudiando la dosis de ECH (porcentaje sobre almidón), adición de amoníaco (moles de NH3/moles de ECH) y tiempo de adición de la ECH (min), entrecruzando almidón total o parcialmente gelatinizado. La reacción fue seguida midiendo la viscosidad del sistema reaccionante. Las muestras se caracterizaron por espectroscopia IR y RMN 13C, microscopia electrónica de barrido y determinando el hinchamiento en varios fluidos, tales como fluido gástrico simulado (FGS) y fluido intestinal simulado (FIS). El tiempo del entrecruzamiento y la viscosidad máxima obtenida solo fueron influidos significativamente por la dosis de ECH. El tiempo fluctuó entre 60 y 150 min, mientras que la viscosidad varió de 110 a 170 mPa · s . Se encontró una elevada correlación entre la absorbancia IR a 2 930 cm-1 (grupos CH2) y la viscosidad, indicando la posibilidad de cuantificar el grado de entrecruzamiento por esta vía. La microscopia electrónica permitió observar las muestras de almidón entrecruzado como materiales relativamente homogéneos, mientras para el almidón natural se apreciaron gránulos de 10 mm de díametro. Los mejores resultados se lograron aplicando 10 % ECH y 1 mol NH3/mol ECH, evidenciado esto por elevados valores del hinchamiento máximo, gran velocidad (bajos tiempos) para alcanzarlo en FIS y tiempos mayores en FGS

The Effect of Temperature on the Absorption and Fluorescence Spectra of Impurity Crystals

A meta-analysis approach was used to assess the effect of dredging induced changes in sediment composition, under different conditions of natural physical disturbance, for the structure and function of marine benthic macrofaunal communities. Results showed the sensitivity of macrofaunal communities increased as both the proportion of gravel increased and the level of natural physical disturbance decreased. These findings may be explained by the close association of certain taxa with the gravel fraction, and the influence of natural physical disturbance which, as it increases, tends to restrict the colonisation by these species. We conclude that maintaining the gravel content of surface sediments after dredging and, where practicable, locating extraction sites in areas of higher natural disturbance will minimise the potential for long-term negative impacts on the macrofauna

Proportional Convolution Filters - An Alternative Technique For Non-distorted Image Enhancement

This paper introduces a new class of spatial filters, here coined the proportional convolution filters. These filters are constructed in such way that the values assigned to each kernel cell are weighted as a function of the trigonometric distance of the cells to the kernel centre. A set of high-pass and low-pass proportional filters were designed using a specially tailored algorithm and a Delphi-based code that allows producing multi-dimensional filters. These filters underwent a twofold test. Firstly, the filters were tested against an instructive digital image of a candle flame. This image was employed as it shows large and detailed variations in color tones (low frequencies) and an assortment of possible boundaries between tones (high frequencies). Secondly, the filters were applied to a Landsat-5 TM image containing a variety of landforms. Results showed the efficiency of the filters and the adequacy of an array of kernel sizes to enhance both tonal and edge variations in a digital image, demonstrating that the proportional filters can benefit numerous applications in several fields of Geosciences. © 2012 Sociedade Brasileira de Geofísica.3013139Blom, R.G., Daily, M., Radar Image-Processing for Rock-Type Discrimination (1982) IEEE Transactions On Geoscience and Remote Sensing, 20 (3), pp. 343-351Branco, F.C., (1998) Filtros De Convolução Passa Baixas No Realce Tonal De Imagens, p. 78. , M.Sc. Dissertation. Instituto de Geociências - USP. São Paulo, SP, BrazilCurran, P.J., (1985) Principles of Remote Sensing, p. 282. , Longman Group Limited, London, UKDrury, S.A., (2001) Image Interpretation In Geology, p. 296. , Blackwell Science, UK, 3rd editionHoldermann, F., Bohner, M., Bargel, B., Kazmierczak, H., Review of Automatic Image Processing (1978) Photogrammetria, 34, pp. 225-258Mather, P.M., (1999) Computer Processing of Remotely-Sensed Images: An Introduction, p. 292. , John Wiley & Sons Inc., UKSouza, F.C.R., Drury, S.A., Denniss, A.M., Carlton, R.W.T., Rothery, D.A., Restoration of Corrupted Optical Fuyo-1 (JERS-1) Data Using Frequency Domain Techniques (1996) Photogrammetric Engineering & Remote Sensing, 62 (9), pp. 1037-1047Tao, L., Asari, V., An Integrated Neighborhood Dependent Approach for Nonlinear Enhancement of Color Images (2004) International Conference On Information Technology, Proceedings, 2, pp. 138-13

Metals in waste foundry sands and an evaluation of their leaching and transport to groundwater

While most waste molding foundry sands (WFSs) are not hazardous in nature, regulatory agencies are often reluctant to permit their beneficial use in agricultural and geotechnical applications due to concerns over metal leaching. The objective of this study was to quantify total and Toxicity Characteristic Leaching Procedure (TCLP) metals in 16 waste sands from Brazilian ferrous foundries and assess their potential to leach metals to groundwater using a probabilistic model developed by the U.S. EPA. Total and TCLP metal concentrations in the non-hazardous sands fell within ranges as reported in the literature, although some of the leachate concentrations were found to exceed drinking water and groundwater maximum contaminant levels MCLs. Leachate values above the MCLs were then used in the model to estimate groundwater concentrations at hypothetical wells up to 400 m downgradient from the land application unit. A conservative scenario of one hectare of land applied WFS and high annual rainfall totals (> 1219 mm/year) suggested that groundwater concentrations of Ba, Hg, Mn, Ni, and Pb could potentially exceed health-based MCLs at most wells. Compared to moderate rainfall totals (813–1016 mm/year), the model demonstrated that wet climates can exacerbate the transport of metals from unconsolidated applications of WFS; however, the use of TCLP results as model input values is not considered appropriate for most byproduct beneficial use scenarios since it simulates low pH conditions within a municipal landfill

Complex magnetic states of heavy fermion compound CeGe

The intermetallic compound CeGe exhibits unusual magnetic behavior due to the interplay between the Kondo and the antiferromagnetic coupling. This particular system is interesting because the Kondo temperature is close to the Néel temperature, resulting in a close competition between the low-temperature interactions, which can be tuned by means of varying external parameters such as pressure and applied magnetic field. Interestingly, magnetization measurements up to 12 kbar reveal that the Néel temperature is not affected by pressure. Measurements of the electrical resistivity, however, show that the sharp upturn appearing below TN is sensitive to pressures up to 15 kbar. This suggests that pressure may change the complex antiferromagnetic spin structure. The validity of an explanation based on the magnetic superzones seen in the rare earths is discussed here