180 research outputs found

    Automatic domain ontology extraction for context-sensitive opinion mining

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    Automated analysis of the sentiments presented in online consumer feedbacks can facilitate both organizations’ business strategy development and individual consumers’ comparison shopping. Nevertheless, existing opinion mining methods either adopt a context-free sentiment classification approach or rely on a large number of manually annotated training examples to perform context sensitive sentiment classification. Guided by the design science research methodology, we illustrate the design, development, and evaluation of a novel fuzzy domain ontology based contextsensitive opinion mining system. Our novel ontology extraction mechanism underpinned by a variant of Kullback-Leibler divergence can automatically acquire contextual sentiment knowledge across various product domains to improve the sentiment analysis processes. Evaluated based on a benchmark dataset and real consumer reviews collected from Amazon.com, our system shows remarkable performance improvement over the context-free baseline

    Information Granulation for the Design of Granular Information Retrieval Systems

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    With the explosive growth of the amount of information stored on computer networks such as the Internet, it is increasingly more difficult for information seekers to retrieve relevant information. Traditional document ranking functions employed by Internet search engines can be enhanced to improve the effectiveness of information retrieval (IR). This paper illustrates the design and development of a granular IR system to facilitate domain specific search. In particular, a novel computational model is designed to rank documents according the searchers’ specific granularity requirements. The initial experiments confirm that our granular IR system outperforms a classical vector-based IR system. In addition, user-based evaluations also demonstrate that our granular IR system is effective when compared with a well-known Internet search engine. Our research work opens the door to the design and development of the next generation of Internet search engines to alleviate the problem of information overload

    Linking the hydrodynamic and kinetic description of a dissipative relativistic conformal theory

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    We use the entropy production variational method to associate a one particle distribution function to the assumed known energy-momentum and entropy currents describing a relativistic conformal fluid. Assuming a simple form for the collision operator we find this one particle distribution function explicitly, and show that this method of linking the hydro and kinetic description is a non trivial generalization of Grad's ansatz. The resulting constitutive relations are the same as in the conformal dissipative type theories discussed in J. Peralta-Ramos and E. Calzetta, Phys. Rev. D {\bfseries 80}, 126002 (2009). Our results may prove useful in the description of freeze-out in ultrarelativistic heavy-ion collisions.Comment: v2: 23 pages, no figures, accepted in Phys. Rev.

    Crustal heterogeneity of the moon viewed from the Galileo SSI camera: Lunar sample calibrations and compositional implications

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    Summaries are given of the spectral calibration, compositional parameters, nearside color, and limb and farside color of the Moon. The farside of the Moon, a large area of lunar crust, is dominated by heavily cratered terrain and basin deposits that represent the products of the first half billion years of crustal evolution. Continuing analysis of the returned lunar samples suggest a magma ocean and/or serial magmatism model for evolution of the primordial lunar crust. However, testing either hypothesis requires compositional information about the crustal stratigraphy and lateral heterogeneity. Resolution of this important planetary science issue is dependent on additional data. New Galileo multispectral images indicate previously unknown local and regional compositional diversity of the farside crust. Future analysis will focus on individual features and a more detailed assessment of crustal stratigraphy and heterogeneity

    Effect of boundary conditions on diffusion in two-dimensional granular gases

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    We analyze the influence of boundary conditions on numerical simulations of the diffusive properties of a two dimensional granular gas. We show in particular that periodic boundary conditions introduce unphysical correlations in time which cause the coefficient of diffusion to be strongly dependent on the system size. On the other hand, in large enough systems with hard walls at the boundaries, diffusion is found to be independent of the system size. We compare the results obtained in this case with Langevin theory for an elastic gas. Good agreement is found. We then calculate the relaxation time and the influence of the mass for a particle of radius RsR_s in a sea of particles of radius RbR_b. As granular gases are dissipative, we also study the influence of an external random force on the diffusion process in a forced dissipative system. In particular, we analyze differences in the mean square velocity and displacement between the elastic and inelastic cases.Comment: 15 figures eps figures, include

    Microstructure and Magnetic Properties of Very Thin CoCr Films Deposited on Different Underlayers by rf-Sputtering

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    Very thin CoCr films deposited on different underlayers on glass disk substrates were studied by the magneto-optic Kerr effect, VSM, torque magnetometry and TEM selected area diffraction. Square or near square perpendicular loops were obtained from Co/Ti, CoCr/Au, CoCr/Al, CoCr/C and CoCr/Si films. TEM SAD study revealed that the crystalline structure is a key factor determining the magnetic anisotropy of the very thin CoCr films. In particular, the c-axis of the hep CoCr films which exhibit square perpendicular loops is perpendicular to the film plane whilst that of the CoCr films which exhibit a thin and flat perpendicular loop lies in the film plane. The texture of the very thin CoCr films deposited on different underlayers is mainly dependent on the structure and texture of underlayers. The relation between the structure of CoCr and its underlayers is discussed

    Instability of Myelin Tubes under Dehydration: deswelling of layered cylindrical structures

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    We report experimental observations of an undulational instability of myelin figures. Motivated by this, we examine theoretically the deformation and possible instability of concentric, cylindrical, multi-lamellar membrane structures. Under conditions of osmotic stress (swelling or dehydration), we find a stable, deformed state in which the layer deformation is given by \delta R ~ r^{\sqrt{B_A/(hB)}}, where B_A is the area compression modulus, B is the inter-layer compression modulus, and h is the repeat distance of layers. Also, above a finite threshold of dehydration (or osmotic stress), we find that the system becomes unstable to undulations, first with a characteristic wavelength of order \sqrt{xi d_0}, where xi is the standard smectic penetration depth and d_0 is the thickness of dehydrated region.Comment: 5 pages + 3 figures [revtex 4

    12mm line survey of the dense molecular gas towards the W28 field TeV gamma-ray sources

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    We present 12mm Mopra observations of dense molecular gas towards the W28 supernova remnant (SNR) field. The focus is on the dense molecular gas towards the TeV gamma-ray sources detected by the H.E.S.S. telescopes, which likely trace the cosmic-rays from W28 and possibly other sources in the region. Using the NH3 inversion transitions we reveal several dense cores inside the molecular clouds, the majority of which coincide with high-mass star formation and HII regions, including the energetic ultra-compact HII region G5.89-0.39. A key exception to this is the cloud north east of W28, which is well-known to be disrupted as evidenced by clusters of 1720MHz OH masers and broad CO line emission. Here we detect broad NH3, up to the (9,9) transition, with linewidths up to 16 km/s. This broad NH3 emission spatially matches well with the TeV source HESS J1801-233 and CO emission, and its velocity dispersion distribution suggests external disruption from the W28 SNR direction. Other lines are detected, such as HC3N and HC5N, H2O masers, and many radio recombination lines, all of which are primarily found towards the southern high-mass star formation regions. These observations provide a new view onto the internal structures and dynamics of the dense molecular gas towards the W28 SNR field, and in tandem with future higher resolution TeV gamma-ray observations will offer the chance to probe the transport of cosmic-rays into molecular clouds.Comment: 18 pages, 10 figures, 5 tables, accepted for publication in MNRAS. Online appendices containing additional molecular line: fit parameters, maps, PV plots & spectra, will be available through MNRA

    An Integrated Clustering Method for Pedagogical Performance

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    We present an interdisciplinary approach to data clustering, based on an algorithm originally developed for the Big Data Modelling of Sustainable Development Goals (BDMSDG). Its application context combines mechanics of machine learning techniques with underlying domain knowledge–unifying the narratives of data scientists and educationists in searching for potentially useful information in historical data. From an initial structure masking, results from multiple samples of identified set of two to five clusters, reveal a consistent number of three clear clusters. We present and discuss the results from a technical and soft perspectives to stimulate interdisciplinarity and support decision making. We explain how the findings of this paper present not only continuity of on–going clustering optimisation, but also an intriguing starting point for interdisciplinary discussions aimed at enhancement of students performance

    Self-similarity of Mean Flow in Pipe Turbulence

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    Based on our previous modified log-wake law in turbulent pipe ‡flows, we invent two compound similarity numbers (Y;U), where Y is a combination of the inner variable y+ and outer variable , and U is the pure exect of the wall. The two similarity numbers can well collapse mean velocity profile data with different moderate and large Reynolds numbers into a single universal profile. We then propose an arctangent law for the buffer layer and a general log law for the outer region in terms of (Y;U). From Milikan’s maximum velocity law and the Princeton superpipe data, we derive the von Kármán constant = 0:43 and the additive constant B=6. Using an asymptotic matching method, we obtain a self-similarity law that describes the mean velocity profile from the wall to axis; and embeds the linear law in the viscous sublayer, the quartic law in the bursting sublayer, the classic log law in the overlap, the sine-square wake law in the wake layer, and the parabolic law near the pipe axis. The proposed arctangent law, the general log law and the self-similarity law have been compared with the high-quality data sets, with diffrent Reynolds numbers, including those from the Princeton superpipe, Loulou et al., Durst et al., Perry et al., and den Toonder and Nieuwstadt. Finally, as an application of the proposed laws, we improve the McKeon et al. method for Pitot probe displacement correction, which can be used to correct the widely used Zagarola and Smits data set
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