1,481 research outputs found

    Rotation of an immersed cylinder sliding near a thin elastic coating

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    It is known that an object translating parallel to a soft wall in a viscous fluid produces hydro- dynamic stresses that deform the wall, which, in turn, results in a lift force on the object. Recent experiments with cylinders sliding under gravity near a soft incline, which confirmed theoretical arguments for the lift force, also reported an unexplained steady-state rotation of the cylinders [Saintyves et al. PNAS 113(21), 2016]. Motivated by these observations, we show, in the lubrication limit, that an infinite cylinder that translates in a viscous fluid parallel to a soft wall at constant speed and separation distance must also rotate in order to remain free of torque. Using the Lorentz reciprocal theorem, we show analytically that for small deformations of the elastic layer, the angular velocity of the cylinder scales with the cube of the sliding speed. These predictions are confirmed numerically. We then apply the theory to the gravity-driven motion of a cylinder near a soft incline and find qualitative agreement with the experimental observations, namely that a softer elastic layer results in a greater angular speed of the cylinder.Comment: 16 pages, 4 figure

    Secrecy Capacity Analysis Over κ–μ Fading Channels: Theory and Applications

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    MIXTURE CONVERSION WITH CONFIRMABLE ALLOCATION IN CLOUD USING CP-ABE SCHEM

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    Within the computing atmosphere, cloud servers may have many data services, for example remote data storage furthermore to outsourced delegation computation. For data storage, servers store up numerous volume of shared information, which may be utilized by way of authoritative users. Within our work we offer anti-collusion circuit cipher text based file   encryption process because cipher text based file  encryption process is conceptually faster to established method of access control. We try to improve the cipher text based file encryption methods by verifiable delegation in cloud system to think about data privacy, fine-grained data access control furthermore to verifiability of delegation. In hybrid representation of verifiable delegation cipher text-policy based file  encryption, a circuit cipher text-policy based file  encryption, a symmetric file  encryption system by permitting an secure-then-mac mechanism are functional to make certain privacy, fine-grained access control furthermore to verifiable delegation

    Search and analysis of giant radio galaxies with associated nuclei (SAGAN) -- I : New sample and multi-wavelength studies

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    We present the first results of a project called SAGAN, which is dedicated solely to the studies of relatively rare megaparsec-scale radio galaxies in the Universe, called giant radio galaxies (GRGs). We have identified 162 new GRGs primarily from the NVSS with sizes ranging from ~0.71 Mpc to 2.82 Mpc in the redshift range of ~0.03 - 0.95, of which 23 are hosted by quasars (giant radio quasars, GRQs). As part of the project SAGAN, we have created a database of all known GRGs, the GRG catalogue, from the literature (including our new sample); it includes 820 sources. For the first time, we present the multi-wavelength properties of the largest sample of GRGs. Our results establish that the distributions of the radio spectral index and the black hole mass of GRGs do not differ from the corresponding distributions of normal-sized radio galaxies (RGs). However, GRGs have a lower Eddington ratio (ER) than RGs. Using the mid-infrared data, we classified GRGs in terms of their accretion mode: either a high-power radiatively efficient high-excitation state, or a radiatively inefficient low-excitation state. We find that GRGs in high-excitation state statistically have larger sizes, stronger radio power, jet kinetic power, and higher ER than those in low-excitation state. Our analysis reveals a strong correlation between the ER and the scaled jet kinetic power, which suggests a disc-jet coupling. Our environmental study reveals that ~10% of all GRGs may reside at the centres of galaxy clusters, in a denser galactic environment, while the majority appears to reside in a sparse environment. We find that the probability of BCG as a GRG is quite low. We present new results for GRGs that range from black hole mass to large-scale environment properties. We discuss their formation and growth scenarios, highlighting the key physical factors that cause them to reach their gigantic size. Abridged.Comment: Accepted for publication in Astronomy & Astrophysics. 14 figures, 7 tables and 7 montages. Comments are welcome. "SAGAN Project website https://sites.google.com/site/anantasakyatta/sagan

    Co-channel interference and background noise in κ - μ fading channels

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    In this letter, we derive novel analytical and closed form expressions for the outage probability, when the signal-of- interest (SoI) and the interferer experience kappa-mu fading in the presence of Gaussian noise. Most importantly, these expressions hold true for independent and non-identically distributed kappa-mu variates, without parameter constraints. We also find the asymptotic behaviour when the average signal to noise ratio of the SoI is significantly larger than that of the interferer. It is worth highlighting that our new solutions are very general owing to the flexibility of the kappa-mu fading model21512151218CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ304248/2014-2This work was supported by the U.K. Engineering and Physical Sciences Research Council under Grant Reference EP/L026074/1 and by CNPq under Grant Reference 304248/2014-2

    Diagnostic accuracy of fine needle aspiration cytology in soft tissue tumors: our institutional experience

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    Background: Diagnosis of Soft tissue tumors by FNAC (Fine needle aspiration cytology) is one of the diagnostic modality of choice in pathological evaluation of soft tissue neoplasms especially to differentiate from the non-neoplastic soft tissue lesions. It is challenging and controversial. Very few centers rely on simple FNAC for diagnosis which is largely due to a lack of experience, familiarity, confidence and tricky cytological features.Methods:We have studied 140 cases of soft-tissue tumors by simple FNAC procedure done by cytopathologist from 01/01/2012 to 31/12/2012. After considering thorough history, clinical, radiology and other findings all cases were reported by the experienced faculty in cytopathology section of our institute.Results:Out of total 140 cases of soft tissue tumors 131 (93.58%) were benign and 9 (6.42%) were malignant. In benign category maximum numbers were lipoma 105 cases (80.15%) followed by benign neural tumors 5 cases (3.82%), ganglion 4 cases (3.05%), benign fibrohistiocytic lesions 2 cases (1.53%) and others. Conclusions: Current study demonstrates that FNAC is valuable as a primary tool in diagnosing soft tissue tumors specifically benign lesions like lipomatous tumors, high grade malignant sarcoma and recurrent lesions. Findings are well supported by histopathological correlation

    The interaction of lean and building information modeling in construction

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    Lean construction and Building Information Modeling are quite different initiatives, but both are having profound impacts on the construction industry. A rigorous analysis of the myriad specific interactions between them indicates that a synergy exists which, if properly understood in theoretical terms, can be exploited to improve construction processes beyond the degree to which it might be improved by application of either of these paradigms independently. Using a matrix that juxtaposes BIM functionalities with prescriptive lean construction principles, fifty-six interactions have been identified, all but four of which represent constructive interaction. Although evidence for the majority of these has been found, the matrix is not considered complete, but rather a framework for research to explore the degree of validity of the interactions. Construction executives, managers, designers and developers of IT systems for construction can also benefit from the framework as an aid to recognizing the potential synergies when planning their lean and BIM adoption strategies

    S-Box Implementation of AES is NOT side-channel resistant

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    Several successful cache-based attacks have provided strong impetus for developing side channel resistant software implementations of AES. One of the best-known countermeasures - use of a minimalist 256-byte look-up table - has been employed in the latest (assembly language) versions. Software and hardware prefetching and out-of-order execution in modern processors have served to further shrink the attack surface. Despite these odds, we devise and implement two strategies to retrieve the complete AES key. The first uses adaptively chosen plaintext and random plaintext in a 2-round attack. The second strategy employs only about 50 blocks of random plaintext in a novel single round attack. The attack can be extended to spying on table accesses during decryption in a ciphertext-only attack. We also present an analytical model to explain the effect of false positives and false negatives and capture various practical tradeoffs involving number of blocks of plaintext, offline computation time for key retrieval and success probability
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