5,387 research outputs found
A hybrid information retrieval model using metadata and text
No full textInformation retrieval (IR) with metadata tends to have high precision as long as the user expresses the information need accurately but may suffer from low recall because queries are too exact with the specification of the metadata fields. On the other hand, full-text retrieval tends to suffer more from low precision especially when queries are simple and the number of documents is large. While structured queries targeted at metadata can be quite precise and the retrieval results can be accurate, it is not easy to construct an effective structured query without understanding the characteristics of the metadata. Casual users, however, are usually interested in spending time to understand the meaning of various metadata. In this paper, we propose a hybrid IR model that searches both metadata and text fields of documents. User queries are analyzed and converted into a hybrid query automatically. Experiments show that the hybrid approach outperforms either of the cases, i.e. searching text only or metadata only
Pulsating flow and heat transfer in an annulus partially filled with porous media
No full textA numerical study is made of heat transfer characteristics from pulsating flow in a concentric annulus partially filled with porous media. The unsteady Navier-Stokes equations with the Brinkman-Forchheimer-extended Darcy model in the porous region are solved by using finite volume techniques. Changes in convective heat transfer and in effective axial heat conduction due to pulsation are investigated over broad ranges of the relevant parameters, i.e., the thickness of the porous layer and the frequency and amplitude of pulsation. The results obtained indicate that the effective axial thermal conductivity is substantially increased by pulsation, and this augmentation is more pronounced by partial fillings of porous material
EXPERIMENTAL-STUDY OF UNIFORM-SHEAR FLOW PAST A ROTATING CYLINDER
No full textAn experimental study is made of two-dimensional uniform-shear flow (U=U-c + Gy) past a rotating cylinder of diameter D. A water-tunnel, equipped with a shear generator was constructed. Laser-Doppler velocity measurements were undertaken to describe the wake characteristics. Data are compiled over the ranges of 600 less than or equal to Re less than or equal to 1,200, the shear parameter K[=GD/U-c] up to 0.15, and the value of the cylinder rotation parameter alpha[=omega D/2U(c)], -2.0 less than or equal to alpha less than or equal to 2.0. The power spectra of velocity measurements at downstream locations were analyzed to examine the vortex shedding patterns. In general, the dominant shedding frequency is shifted to a higher value as \alpha\ and K increase. When \alpha\ increases beyond a certain threshold value, the dominant frequency becomes less distinct. If \alpha\ takes a value larger than around 1.5, the velocity field becomes randomized and diffuse, and the organized Karman vortex street activity weakens. The variations of the Strouhal number with K and alpha are described The evolution of mean velocity profiles in the wakefield is depicted. Characterizations of the velocity profiles, as K and alpha vary, are made based on the measurement data
DISCRETE VORTEX SIMULATION OF PULSATING FLOW BEHIND A NORMAL PLATE
No full textA numerical study is made of the separated flow behind a flat plate. The plate is placed normal to the direction of the approach flow. The oncoming freestream velocity contains a pulsating part, U infinity = U-0(1+A(0)cosf(p)t). The temporal behavior of vortex shedding patterns is scrutinized over broad ranges of the two externally specified parameters, i.e., the pulsation amplitude (A(0) less than or equal to 0.6), and the dimensionless pulsation frequency, (f(b) less than or equal to 0.32). A version of the discrete vortex method is utilized. The variable-position nascent vortex technique is applied, and it proves to be adequate for pulsating approach flows. The numerical results clearly capture the existence of lock-on when f(p) exceeds a threshold value. The modulation of vorticity shedding is also detected when f(p) is reasonably low. The influence of A(0) on the flow characteristics is examined in detail. As A(0) increases to a moderate value (e.g., A(0) less than or equal to 0.6), an appreciable broadening is seen of the range of f(p) for which lock-an occurs. Based on the numerical results, three characteristic flow modes in the wakes are identified. These findings are qualitatively consistent with the existing flow visualization studies for a cylinder
The SSC of the Generalised Jahangir’s Graph Jm,k and its Algebraic Characterizations
No full textIn this article, we present important combinatorial and algebraicproperties of spanning simplicial complex (SSC) of the generalised Jahangir’sgraph Jm,k. We describe the relation to find f−vectors associatedto Δs(Jm,k) and determine the Hilbert series for the SR-ring KΔs(Jm,k).In the end, we present the associated primes of the facet ideal IF(Δs(Jm,k))and the Cohen-Macaulay characterization of the SR-ring of Δs(Jm,k).AMS (MOS) Subject Classification Codes: Primary 13-P10, Secondary 13-F20, 13-C14, 13-H10.Corresponding Author: Agha KashifKey Words: Simplicial Complexes, f-vectors, Spanning Trees, Face Ring, Hilbert Series, CohenMacaulay
To <i>JM</i> on Its 75th Anniversary
No full text This article discusses how Journal of Marketing ( JM) has influenced marketing science and practice by publishing articles on substantive topics relevant to customers, managers, organizations, markets, and society. The journal's 75th anniversary coincides with the 50th anniversary of the Marketing Science Institute (MSI). Frequently, JM and MSI have collaborated to address important substantive marketing issues identified in MSI's Research Priorities. The author highlights seminal articles on brand equity; business-to-business marketing (including sales force management); connecting marketing information, metrics, and strategy; consumer behavior; innovation, new product development. and product management; marketing orientation and capabilities; and market research, methodology and services. She also draws attention to articles that have won the Sheth Foundation/ JM Award and the H. Paul Root Award. The article describes how JM‘s knowledge dissemination is amplified by powerful social network effects. Ideas in JM articles diffuse through the business community, influencing the mind-set of managers worldwide. </jats:p
JM-20, a Benzodiazepine-Dihydropyridine Hybrid Molecule, Inhibits the Formation of Alpha-Synuclein-Aggregated Species
No full text\ua9 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.Studies showed that JM-20, a benzodiazepine-dihydropyridine hybrid molecule, protects against rotenone and 6-hydroxydopamine neurotoxicity. However, its protective effects against cytotoxicity induced by endogenous neurotoxins involved in Parkinson’s disease (PD) pathogenesis have never been investigated. In this study, we evaluated the ability of JM-20 to inhibit alpha-synuclein (aSyn) aggregation. We also evaluated the interactions of JM-20 with aSyn by molecular docking and molecular dynamics and assessed the protective effect of JM-20 against aminochrome cytotoxicity. We demonstrated that JM-20 induced the formation of heterogeneous amyloid fibrils, which were innocuous to primary cultures of mesencephalic cells. Moreover, JM-20 reduced the average size of aSyn positive inclusions in H4 cells transfected with SynT wild-type and synphilin-1-V5, but not in HEK cells transfected with synphilin-1-GFP. In silico studies showed the interaction between JM-20 and the aSyn-binding site. Additionally, we showed that JM-20 protects SH-SY5Y cells against aminochrome cytotoxicity. These results reinforce the potential of JM-20 as a neuroprotective compound for PD and suggest aSyn as a molecular target for JM-20
Effect of surface undulation on polymer adsorption
No full textWe study the adsorption of a long, flexible polymer (ideal or self-avoiding chain) interacting with a rough surface via a finite-range attraction. Within the Edwards equation approach, we develop a variational method to find the segmental distribution and the free energy of an adsorbed chain. As adsorption becomes strong, the segments tend to be localized within the valleys rather than above the hills of the undulating surface, resulting in a decrease of adsorption thickness. Consequently, the surface undulation enhances adsorption in the case of a strongly adsorbed chain whereas the undulation suppresses it for a weakly adsorbed one, since the enhanced entropic repulsion is dominant over the attraction from the surface. Considering the surface with undulation characterized by a Gaussian correlation as an example, we find an optimal correlation length at which the adsorption becomes the strongest and a critical correlation length below which desorption is induced.open1110sci
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