991 resultados para 378.014


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Let be a set of points in the plane. A geometric graph on is said to be locally Gabriel if for every edge in , the Euclidean disk with the segment joining and as diameter does not contain any points of that are neighbors of or in . A locally Gabriel graph(LGG) is a generalization of Gabriel graph and is motivated by applications in wireless networks. Unlike a Gabriel graph, there is no unique LGG on a given point set since no edge in a LGG is necessarily included or excluded. Thus the edge set of the graph can be customized to optimize certain network parameters depending on the application. The unit distance graph(UDG), introduced by Erdos, is also a LGG. In this paper, we show the following combinatorial bounds on edge complexity and independent sets of LGG: (i) For any , there exists LGG with edges. This improves upon the previous best bound of . (ii) For various subclasses of convex point sets, we show tight linear bounds on the maximum edge complexity of LGG. (iii) For any LGG on any point set, there exists an independent set of size .

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The inhibition performance of ibuprofen triazole (IT) on mild steel (MS) corrosion in 1.0 M HCl and 0.5 M H2SO4 has been investigated by using electrochemical (potentiodynamic polarization and electrochemical impedance spectroscopy), gravimetric, and quantum chemical studies. Electrochemical investigation indicates that IT hampers MS corrosion via adsorption through a mixed inhibition mechanism. The protection ability of IT increases with an increasing concentration of inhibitor and decreases with increasing temperature. The adsorption of IT molecules on MS surface follows the Langmuir adsorption isotherm. Certain quantum chemical parameters were calculated to ascertain the correlation between inhibitive effect and molecular structure of IT.

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The problem of scaling up data integration, such that new sources can be quickly utilized as they are discovered, remains elusive: Global schemas for integrated data are difficult to develop and expand, and schema and record matching techniques are limited by the fact that data and metadata are often under-specified and must be disambiguated by data experts. One promising approach is to avoid using a global schema, and instead to develop keyword search-based data integration-where the system lazily discovers associations enabling it to join together matches to keywords, and return ranked results. The user is expected to understand the data domain and provide feedback about answers' quality. The system generalizes such feedback to learn how to correctly integrate data. A major open challenge is that under this model, the user only sees and offers feedback on a few ``top-'' results: This result set must be carefully selected to include answers of high relevance and answers that are highly informative when feedback is given on them. Existing systems merely focus on predicting relevance, by composing the scores of various schema and record matching algorithms. In this paper, we show how to predict the uncertainty associated with a query result's score, as well as how informative feedback is on a given result. We build upon these foundations to develop an active learning approach to keyword search-based data integration, and we validate the effectiveness of our solution over real data from several very different domains.

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This paper discusses a novel high-speed approach for human action recognition in H.264/AVC compressed domain. The proposed algorithm utilizes cues from quantization parameters and motion vectors extracted from the compressed video sequence for feature extraction and further classification using Support Vector Machines (SVM). The ultimate goal of the proposed work is to portray a much faster algorithm than pixel domain counterparts, with comparable accuracy, utilizing only the sparse information from compressed video. Partial decoding rules out the complexity of full decoding, and minimizes computational load and memory usage, which can result in reduced hardware utilization and faster recognition results. The proposed approach can handle illumination changes, scale, and appearance variations, and is robust to outdoor as well as indoor testing scenarios. We have evaluated the performance of the proposed method on two benchmark action datasets and achieved more than 85 % accuracy. The proposed algorithm classifies actions with speed (> 2,000 fps) approximately 100 times faster than existing state-of-the-art pixel-domain algorithms.

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In this study, we report on the accuracy, precision and clinical acceptability of the five blood glucose meters available in India. Glucose levels of 100 blood samples were measured with each meter, at IISc health centre laboratory under same conditions and the results were compared with laboratory reference standard. In order to calculate the coefficient of variation (CV), each sample was tested three times. None of the glucometer showed 100 % compliance on CV measure. In terms of accuracy, none of the glucometer satisfied the most stringent ADA-1994 standard. In general all the glucometers showed improved accuracy with respect to the most relaxed ISO 1597:2003 standard. The Clarke error grid analysis was performed to assess the clinical acceptability of the glucometers. All five glucometers had more than 90 % of test results in Zone A and B. Bland-Altman analysis indicates that all glucometers show a positive bias, indicating that the measured values tend to be higher than the laboratory reference standard.

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This paper presents the stability analysis of functionally graded plate integrated with piezoelectric actuator and sensor at the top and bottom face, subjected to electrical and mechanical loading. The finite element formulation is based on first order and higher order shear deformation theory, degenerated shell element, von-Karman hypothesis and piezoelectric effect. The equation for static analysis is derived by using the minimum energy principle and solutions for critical buckling load is obtained by solving eigenvalue problem. The material properties of the functionally graded plate are assumed to be graded along the thickness direction according to simple power law function. Two types of boundary conditions are used, such as SSSS (simply supported) and CSCS (simply supported along two opposite side perpendicular to the direction of compression and clamped along the other two sides). Sensor voltage is calculated using present analysis for various power law indices and FG (functionally graded) material gradations. The stability analysis of piezoelectric FG plate is carried out to present the effects of power law index, material variations, applied mechanical pressure and piezo effect on buckling and stability characteristics of FG plate.

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The micro-level properties of different self compacting concrete (SCC) mixes with and without mineral admixures are studied. The study considers SCC as a two phase material consisting of matrix and aggregate. Micro indentation technique is employed to obtain the hardness of individual phases and to compute the micro-property (modulus of elasticity). Using a self consistent homogenization procedure, the micro-property is scaled-up to obtain the macro-property which is shown to agree with the experimentally obtained macro values. It is seen that there exists a smaller interfacial transition zone at different ages of curing across all the mixes due to the presence of more fines in SCC. Also, there is no significant change in the property of the SCC having no fly ash or silica fume beyond 28 days whereas a substantial change in the micro and macro properties are seen in the SCC having fly ash and silica fume.

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To calculate static response properties of a many-body system, local density approximation (LDA) can be safely applied. But, to obtain dynamical response functions, the applicability of LDA is limited bacause dynamics of the system needs to be considered as well. To examine this in the context of cold atoms, we consider a system of non-interacting spin4 fermions confined by a harmonic trapping potential. We have calculated a very important response function, the spectral intensity distribution function (SIDF), both exactly and using LDA at zero temperature and compared with each other for different dimensions, trap frequencies and momenta. The behaviour of the SIDF at a particular momentum can be explained by noting the behaviour of the density of states (DoS) of the free system (without trap) in that particular dimension. The agreement between exact and LDA SIDFs becomes better with increase in dimensions and number of particles.

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The calculation of First Passage Time (moreover, even its probability density in time) has so far been generally viewed as an ill-posed problem in the domain of quantum mechanics. The reasons can be summarily seen in the fact that the quantum probabilities in general do not satisfy the Kolmogorov sum rule: the probabilities for entering and non-entering of Feynman paths into a given region of space-time do not in general add up to unity, much owing to the interference of alternative paths. In the present work, it is pointed out that a special case exists (within quantum framework), in which, by design, there exists one and only one available path (i.e., door-way) to mediate the (first) passage -no alternative path to interfere with. Further, it is identified that a popular family of quantum systems - namely the 1d tight binding Hamiltonian systems - falls under this special category. For these model quantum systems, the first passage time distributions are obtained analytically by suitably applying a method originally devised for classical (stochastic) mechanics (by Schroedinger in 1915). This result is interesting especially given the fact that the tight binding models are extensively used in describing everyday phenomena in condense matter physics.

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Real time anomaly detection is the need of the hour for any security applications. In this article, we have proposed a real time anomaly detection for H.264 compressed video streams utilizing pre-encoded motion vectors (MVs). The proposed work is principally motivated by the observation that MVs have distinct characteristics during anomaly than usual. Our observation shows that H.264 MV magnitude and orientation contain relevant information which can be used to model the usual behavior (UB) effectively. This is subsequently extended to detect abnormality/anomaly based on the probability of occurrence of a behavior. The performance of the proposed algorithm was evaluated and bench-marked on UMN and Ped anomaly detection video datasets, with a detection rate of 70 frames per sec resulting in 90x and 250x speedup, along with on-par detection accuracy compared to the state-of-the-art algorithms.

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In wireless sensor networks (WSNs), contention occurs when two or more nodes in a proximity simultaneously try to access the channel. The contention causes collisions, which are very likely to occur when traffic is correlated. The excessive collision not only affects the reliability and the QoS of the application, but also the lifetime of the network. It is well-known that random access mechanisms do not efficiently handle correlated-contention, and therefore, suffer from high collision rate. Most of the existing TDMA scheduling techniques try to find an optimal or a sub-optimal schedule. Usually, the situation of correlated-contention persists only for a short duration, and therefore, it is not worthwhile to take a long time to generate an optimal or a sub-optimal schedule. We propose a randomized distributed TDMA scheduling (RD-TDMA) algorithm to quickly generate a feasible schedule (not necessarily optimal) to handle correlated-contention in WSNs. In RD-TDMA, a node in the network negotiates a slot with its neighbors using the message exchange mechanism. The proposed protocol has been simulated using the Castalia simulator to evaluate its runtime performance. Simulation results show that the RD-TDMA algorithm considerably reduces the time required to schedule.

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This paper presents the instrumentation and control architecture for a laboratory based two-stage 4-bed silica gel + water adsorption system. The system consists of primarily two fluids: refrigerant (water vapour) and heat transfer fluid (water) flowing through various components. Heat input to the system is simulated using multiple heaters and ambient air is used as the heat sink. The laboratory setup incorporates a real time National Instruments (NI) controller to control several digital and analog valves, heaters, pumps and fans along with simultaneous data acquisition from various flow, pressure and temperature sensors. The paper also presents in detail the various automated and manual tasks required for successful operation of the system. Finally the system pressure and temperature dynamics are reported and its performance evaluated for various cycle times. (C) 2015 Elsevier Ltd. All rights reserved.

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Single-stranded DNA binding protein (Ssb) of Deinococcus radiodurans comprises N- and C-terminal oligonucleotide/oligosaccharide binding (OB) folds connected by a beta hairpin connector. To assign functional roles to the individual OB folds, we generated three Ssb variants: Ssb(N) (N-terminal without connector), Ssb(NC) (N-terminal with connector) and Ssb(C) (C-terminal), each harboring one OB fold. Both Ssb(N) and Ssb(NC) displayed weak single-stranded DNA (ssDNA) binding activity, compared to the full-length Ssb (Ssb(FL)). The level of ssDNA binding activity displayed by SsbC was intermediate between Ssb(FL) and Ssb(N). Ssb(C) and Ssb(FL) predominantly existed as homo-dimers while Ssb(NC)/Ssb(N) formed different oligomeric forms. In vitro, Ssb(NC) or Ssb(N) formed a binary complex with Ssb(C) that displayed enhanced ssDNA binding activity. Unlike Ssb(FL), Ssb variants were able to differentially modulate topoisomerase-I activity, but failed to stimulate Deinococcal RecA-promoted DNA strand exchange. The results suggest that the C-terminal OB fold is primarily responsible for ssDNA binding. The N-terminal OB fold binds weakly to ssDNA but is involved in multimerization. (C) 2015 The Authors. Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies. This is an open access article under the CC BY-NC-ND license.

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The current study reports on the synthesis and characterization of a new inorganic nano-pigment with an intense blue color and high solar radiation reflective properties (70%). The nano-pigment YIn0.9Mn0.1O3-ZnO was synthesized by a sol-gel combustion method and characterized with the aid of X-Ray diffraction, Raman spectroscopy, Magnetic susceptibility, Transmission electron microscopy, UV ndash;vis-NIR diffuse reflectance spectroscopy and CIE-1976 L*a*b* color measurements. The Rietveld refinement of the XRD patterns of the developed nano-pigment disclosed the existence of YIn0.9Mn0.1O3 and ZnO in a 1:1 ratio with hexagonal crystal structures. For comparison, YIn0.9Mn0.1O3 was also synthesized by the sol gel combustion route and its optical properties compared with that of YIn0.9Mn0.1O3-ZnO. It is interesting to note that the developed YIn0.9Mn0.1O3-ZnO nano-pigmeht exhibits superior blue hue (b* = -40.55) and solar reflectance (R* = 70%) values as compared to the YIn0.9Mn0.1O3 nano-pigment (b* = -22.28, R* = 50%). Most importantly, the potential utility of the nano-pigment as a ``Cool Pigment'' was demonstrated by coating onto roofing materials like aluminum roofing sheets. (C) 2015 Elsevier Ltd. All rights reserved.