1,278 research outputs found
Weighted Random Walk Sampling for Multi-Relational Recommendation
In the information overloaded web, personalized recommender systems are
essential tools to help users find most relevant information. The most
heavily-used recommendation frameworks assume user interactions that are
characterized by a single relation. However, for many tasks, such as
recommendation in social networks, user-item interactions must be modeled as a
complex network of multiple relations, not only a single relation. Recently
research on multi-relational factorization and hybrid recommender models has
shown that using extended meta-paths to capture additional information about
both users and items in the network can enhance the accuracy of recommendations
in such networks. Most of this work is focused on unweighted heterogeneous
networks, and to apply these techniques, weighted relations must be simplified
into binary ones. However, information associated with weighted edges, such as
user ratings, which may be crucial for recommendation, are lost in such
binarization. In this paper, we explore a random walk sampling method in which
the frequency of edge sampling is a function of edge weight, and apply this
generate extended meta-paths in weighted heterogeneous networks. With this
sampling technique, we demonstrate improved performance on multiple data sets
both in terms of recommendation accuracy and model generation efficiency
On the Performance of Short Block Codes over Finite-State Channels in the Rare-Transition Regime
As the mobile application landscape expands, wireless networks are tasked
with supporting different connection profiles, including real-time traffic and
delay-sensitive communications. Among many ensuing engineering challenges is
the need to better understand the fundamental limits of forward error
correction in non-asymptotic regimes. This article characterizes the
performance of random block codes over finite-state channels and evaluates
their queueing performance under maximum-likelihood decoding. In particular,
classical results from information theory are revisited in the context of
channels with rare transitions, and bounds on the probabilities of decoding
failure are derived for random codes. This creates an analysis framework where
channel dependencies within and across codewords are preserved. Such results
are subsequently integrated into a queueing problem formulation. For instance,
it is shown that, for random coding on the Gilbert-Elliott channel, the
performance analysis based on upper bounds on error probability provides very
good estimates of system performance and optimum code parameters. Overall, this
study offers new insights about the impact of channel correlation on the
performance of delay-aware, point-to-point communication links. It also
provides novel guidelines on how to select code rates and block lengths for
real-time traffic over wireless communication infrastructures
Janssen effect and the stability of quasi 2-D sandpiles
We present the results of three dimensional molecular dynamics study of
global normal stresses in quasi two dimensional sandpiles formed by pouring
mono dispersed cohesionless spherical grains into a vertical granular Hele-Shaw
cell. We observe Janssen effect which is the phenomenon of pressure saturation
at the bottom of the container. Simulation of cells with different thicknesses
shows that the Janssen coefficient is a function of the cell
thickness. Dependence of global normal stresses as well as on the
friction coefficients between the grains () and with walls () are
also studied. The results show that in the range of our simulations
usually increases with wall-grain friction coefficient. Meanwhile by increasing
while the other system parameters are fixed, we witness a gradual
increase in to a parameter dependent maximal value
Study the Relation between Working Capital System and Profitability in Auto Manufacturing Industry in India
The new economic policy adopted in India in 1991 known as Liberalization, Privatization and Globalization (LPG model). This policy has been designed to make the Indian economy progressively market oriented and integrate it with the emerging global economy structure. Therefore, in line with this policy it was very indispensable to analyze the working management and some financial ratios in some selected Auto manufacturing companies. The purpose of the study was to analyze the practice of working capital Management and Asset and liquidity ratios in six selected Indian auto manufacturing companies. For this aforementioned study, a time series data for the years 2003- 2012 has been employed and a secondary data from the annual reports of the six companies was solicited. Both qualitative and quantitative paradigms were employed so as to analyze the research. Regarding the relation between working capital and turnover analysis, index of inventory turnover, debtors turnover ratio, total assets turnover ratio and fixed assets turnover ratio were used. . The minimum inventory turnover ratio chain index among all selected companies was founded in Ashok Leyland in 2009-2010 that was 74.60 and the maximum was founded in Maruti Suzuki that was 214.76 in 2010-2011. TVS Motor was denoted by the minimum debtors turnover ratio chain index among all selected companies in 2009-2010 that was 55.68 and the maximum debtors turnover ratio chain index was in Maruti Suzuki that was 438.51 in 2010-2011. TVS Motor was denoted by the minimum total assets turnover ratio chain index among all selected companies in 2008-2009 that was 43.15 and the maximum was Ashok Leyland in 2006-2007 that was 176.92. . The minimum fixed assets turnover ratio chain index among selected companies was founded in Ashok Leyland in 2009-2010 that was 61.94. The maximum fixed assets turnover ratio chain index among, selected companies was founded in Hero MotoCorp in 2005 -2006 that was 174.41. Keywords: Turnover, profitability, âWorking capital Auto manufacturing companiesâ
Magnetic effects on the low-T/|W| instability in differentially rotating neutron stars
Dynamical instabilities in protoneutron stars may produce gravitational waves
whose observation could shed light on the physics of core-collapse supernovae.
When born with sufficient differential rotation, these stars are susceptible to
a shear instability (the "low-T/|W| instability"), but such rotation can also
amplify magnetic fields to strengths where they have a considerable impact on
the dynamics of the stellar matter. Using a new magnetohydrodynamics module for
the Spectral Einstein Code, we have simulated a differentially-rotating neutron
star in full 3D to study the effects of magnetic fields on this instability.
Though strong toroidal fields were predicted to suppress the low-T/|W|
instability, we find that they do so only in a small range of field strengths.
Below 4e13 G, poloidal seed fields do not wind up fast enough to have an effect
before the instability saturates, while above 5e14 G, magnetic instabilities
can actually amplify a global quadrupole mode (this threshold may be even lower
in reality, as small-scale magnetic instabilities remain difficult to resolve
numerically). Thus, the prospects for observing gravitational waves from such
systems are not in fact diminished over most of the magnetic parameter space.
Additionally, we report that the detailed development of the low-T/|W|
instability, including its growth rate, depends strongly on the particular
numerical methods used. The high-order methods we employ suggest that growth
might be considerably slower than found in some previous simulations.Comment: REVTeX 4.1, 21 pages, 18 figures, submitting to Physical Review
Arithmetical rank of the cyclic and bicyclic graphs
We show that for the edge ideals of the graphs consisting of one cycle or two cycles of any length connected through a vertex, the arithmetical rank equals the projective dimension of the corresponding quotient ring
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