16,174 research outputs found
Network Transitivity and Matrix Models
This paper is a step towards a systematic theory of the transitivity
(clustering) phenomenon in random networks. A static framework is used, with
adjacency matrix playing the role of the dynamical variable. Hence, our model
is a matrix model, where matrices are random, but their elements take values 0
and 1 only. Confusion present in some papers where earlier attempts to
incorporate transitivity in a similar framework have been made is hopefully
dissipated. Inspired by more conventional matrix models, new analytic
techniques to develop a static model with non-trivial clustering are
introduced. Computer simulations complete the analytic discussion.Comment: 11 pages, 7 eps figures, 2-column revtex format, print bug correcte
Deterministic creation, pinning, and manipulation of quantized vortices in a Bose-Einstein condensate
We experimentally and numerically demonstrate deterministic creation and
manipulation of a pair of oppositely charged singly quantized vortices in a
highly oblate Bose-Einstein condensate (BEC). Two identical blue-detuned,
focused Gaussian laser beams that pierce the BEC serve as repulsive obstacles
for the superfluid atomic gas; by controlling the positions of the beams within
the plane of the BEC, superfluid flow is deterministically established around
each beam such that two vortices of opposite circulation are generated by the
motion of the beams, with each vortex pinned to the \emph{in situ} position of
a laser beam. We study the vortex creation process, and show that the vortices
can be moved about within the BEC by translating the positions of the laser
beams. This technique can serve as a building block in future experimental
techniques to create, on-demand, deterministic arrangements of few or many
vortices within a BEC for precise studies of vortex dynamics and vortex
interactions.Comment: 9 pages, 7 figure
Slum upgrading: Can the 1.5 °C carbon reduction work with SDGs in these settlements?
The need to improve slum housing is a major urban planning agenda, especially in Africa and Asia. This article addresses whether it seems feasible to do this whilst helping achieve the 1.5 °C agenda, which requires zero carbon power along with enabling the Sustainable Development Goals. Survey data from Jakarta and Addis Ababa on the metabolism and liveability of slums are used to illustrate these issues. The article shows that this is possible due to advances in community-based distributed infrastructure that enable community structures to be retained whilst improving physical conditions. The urban planning implications are investigated to enable these ‘leapfrog’ technologies and a more inclusive approach to slums that enables in situ redevelopment instead of slum clearance, and which could be assisted through climate financing
Determinants of best HR practices in Chinese SMEs
AbstractPurpose– The purpose of this paper is to examine the factors which determine the adoption of best HR practices in Chinese small- and medium-sized enterprises (SMEs).Design/methodology/approach – Regression analysis was utilized to analyse survey data obtained from 345 enterprises operating across China in a wide range of industrial sectors.Findings – Enterprises with greater resources in terms of their size, their relationships with external organizations, their cooperation with foreign partners and the human capital of their CEO were found to be more likely to adopt best HR practices. Contrary to the findings of the existing literature no relationship was found of a relationship between family ownership and the use of best HR practices.Research limitations/implications – The cross-sectional design is an obvious limitation of the study. Other limitations relate to the generalizability of the study findings outside the context in which the research was undertaken, and the use of convenience sampling.Practical implications – Enterprises should consider building strategic relationships with external organizations and developing cooperation with foreign partners as a way of leveraging human resource expertise at a limited cost.Originality/value – This is the first study to examine how differences in the resource endowments of Chinese SMEs influence their adoption of best HR practices.<br /
MAP: Microblogging Assisted Profiling of TV Shows
Online microblogging services that have been increasingly used by people to
share and exchange information, have emerged as a promising way to profiling
multimedia contents, in a sense to provide users a socialized abstraction and
understanding of these contents. In this paper, we propose a microblogging
profiling framework, to provide a social demonstration of TV shows. Challenges
for this study lie in two folds: First, TV shows are generally offline, i.e.,
most of them are not originally from the Internet, and we need to create a
connection between these TV shows with online microblogging services; Second,
contents in a microblogging service are extremely noisy for video profiling,
and we need to strategically retrieve the most related information for the TV
show profiling.To address these challenges, we propose a MAP, a
microblogging-assisted profiling framework, with contributions as follows: i)
We propose a joint user and content retrieval scheme, which uses information
about both actors and topics of a TV show to retrieve related microblogs; ii)
We propose a social-aware profiling strategy, which profiles a video according
to not only its content, but also the social relationship of its microblogging
users and its propagation in the social network; iii) We present some
interesting analysis, based on our framework to profile real-world TV shows
Organizational rewards and employee commitment: a Chinese study
Purpose: The purpose of this study is to assess how the cultural value orientations of individual employees moderate their attitudinal responses to different categories of organizational rewards. Specifically, it seeks to examine how one dimension of traditionality, respect for authority, moderates the relationship between affective organizational commitment and three variables: pay satisfaction, autonomy and satisfaction with supervision. Design/methodology/approach: Hierarchical regression analysis was utilized to analyze survey data obtained from a sample of 290 employees of a major Chinese airline company. Findings: Employees high in traditionality were found to exhibit higher levels of affective commitment when autonomy and satisfaction with supervision was low. When autonomy and satisfaction with supervision was high employees low in traditionality exhibited higher levels of emotional attachment to the organization. Research limitations/implications: The cross-sectional design is an obvious limitation of the study. Another limitation relates to the generalizability of the study findings outside the context in which the research was undertaken. Social implications: Organizations should consider taking the cultural orientations of their workforce into account when developing appropriate human resource policies aimed at heightening employee commitment. This should enhance employee well-being, which is especially important in a global economy characterized by uncertainty and rapid change. Originality/value: This is the first study to examine how employees with different cultural value orientations respond to different categories of organizational rewards, in a predominantly traditional society
Lyapunov exponents for products of complex Gaussian random matrices
The exact value of the Lyapunov exponents for the random matrix product with each , where
is a fixed positive definite matrix and a complex Gaussian matrix with entries standard complex normals, are
calculated. Also obtained is an exact expression for the sum of the Lyapunov
exponents in both the complex and real cases, and the Lyapunov exponents for
diffusing complex matrices.Comment: 15 page
Video Pandemics: Worldwide Viral Spreading of Psy's Gangnam Style Video
Viral videos can reach global penetration traveling through international
channels of communication similarly to real diseases starting from a
well-localized source. In past centuries, disease fronts propagated in a
concentric spatial fashion from the the source of the outbreak via the short
range human contact network. The emergence of long-distance air-travel changed
these ancient patterns. However, recently, Brockmann and Helbing have shown
that concentric propagation waves can be reinstated if propagation time and
distance is measured in the flight-time and travel volume weighted underlying
air-travel network. Here, we adopt this method for the analysis of viral meme
propagation in Twitter messages, and define a similar weighted network distance
in the communication network connecting countries and states of the World. We
recover a wave-like behavior on average and assess the randomizing effect of
non-locality of spreading. We show that similar result can be recovered from
Google Trends data as well.Comment: 10 page
Hierarchies of Predominantly Connected Communities
We consider communities whose vertices are predominantly connected, i.e., the
vertices in each community are stronger connected to other community members of
the same community than to vertices outside the community. Flake et al.
introduced a hierarchical clustering algorithm that finds such predominantly
connected communities of different coarseness depending on an input parameter.
We present a simple and efficient method for constructing a clustering
hierarchy according to Flake et al. that supersedes the necessity of choosing
feasible parameter values and guarantees the completeness of the resulting
hierarchy, i.e., the hierarchy contains all clusterings that can be constructed
by the original algorithm for any parameter value. However, predominantly
connected communities are not organized in a single hierarchy. Thus, we develop
a framework that, after precomputing at most maximum flows, admits a
linear time construction of a clustering \C(S) of predominantly connected
communities that contains a given community and is maximum in the sense
that any further clustering of predominantly connected communities that also
contains is hierarchically nested in \C(S). We further generalize this
construction yielding a clustering with similar properties for given
communities in time. This admits the analysis of a network's structure
with respect to various communities in different hierarchies.Comment: to appear (WADS 2013
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