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&ndash; 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 &ndash; Regression analysis was utilized to analyse survey data obtained from 345 enterprises operating across China in a wide range of industrial sectors.Findings &ndash; 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 &ndash; 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 &ndash; 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 &ndash; 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 $P_N = A_N A_{N-1}...A_1$ with each $A_i = \Sigma^{1/2} G_i^{\rm c}$, where $\Sigma$ is a fixed $d \times d$ positive definite matrix and $G_i^{\rm c}$ a $d \times d$ 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 $2(n-1)$ maximum flows, admits a linear time construction of a clustering \C(S) of predominantly connected communities that contains a given community $S$ and is maximum in the sense that any further clustering of predominantly connected communities that also contains $S$ is hierarchically nested in \C(S). We further generalize this construction yielding a clustering with similar properties for $k$ given communities in $O(kn)$ time. This admits the analysis of a network's structure with respect to various communities in different hierarchies.Comment: to appear (WADS 2013