669 research outputs found

    Cultural diversity and information and communication technology impacts on global virtual teams: An exploratory study.

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    Modern organizations face many significant challenges because of turbulent environments and a competitive global economy. Among these challenges are the use of information and communication technology (ICT), a multicultural workforce, and organizational designs that involve global virtual teams. Ad hoc teams create both opportunities and challenges for organizations and many organizations are trying to understand how the virtual environment affects team effectiveness. Our exploratory study focused on the effects of cultural diversity and ICT on team effectiveness. Interviews with 41 team members from nine countries employed by a Fortune 500 corporation were analyzed. Results suggested that cultural diversity had a positive influence on decision‐making and a negative influence on communication. ICT mitigated the negative impact on intercultural communication and supported the positive impact on decision making. Effective technologies for intercultural communication included e‐mail, teleconferencing combined with e‐Meetings, and team rooms. Cultural diversity influenced selection of the communication media

    Disorder induced superconducting ratchet effect in nanowires

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    A dc voltage drop develops along amorphous indium oxide nanowires that are exposed to an ac bias source. This voltage is anti-symmetric with magnetic field and is characterized by sample specific quasi-periodic magneto-voltage oscillations. The voltage magnitude increases with decreasing temperature below TCT_{C} but saturates at low T. As the disorder of the sample is decreased, the dc voltage is suppressed. We suggest that this rectification is a manifestation of the superconducting ratchet effect in which disorder and geometrical confinement play the role of asymmetric pinning centers. This effect demonstrates the importance of inherent inhomogeneity and vortex motion in the superconductor-insulator transition of disordered superconductors.Comment: 4 pages, 4 figure

    The Multi-Strand Graph for a PTZ Tracker

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    High-resolution images can be used to resolve matching ambiguities between trajectory fragments (tracklets), which is one of the main challenges in multiple target tracking. A PTZ camera, which can pan, tilt and zoom, is a powerful and efficient tool that offers both close-up views and wide area coverage on demand. The wide-area view makes it possible to track many targets while the close-up view allows individuals to be identified from high-resolution images of their faces. A central component of a PTZ tracking system is a scheduling algorithm that determines which target to zoom in on. In this paper we study this scheduling problem from a theoretical perspective, where the high resolution images are also used for tracklet matching. We propose a novel data structure, the Multi-Strand Tracking Graph (MSG), which represents the set of tracklets computed by a tracker and the possible associations between them. The MSG allows efficient scheduling as well as resolving -- directly or by elimination -- matching ambiguities between tracklets. The main feature of the MSG is the auxiliary data saved in each vertex, which allows efficient computation while avoiding time-consuming graph traversal. Synthetic data simulations are used to evaluate our scheduling algorithm and to demonstrate its superiority over a na\"ive one.Comment: 9 pages, 7 figures, AVSS201

    Quantum criticality at the superconductor to insulator transition revealed by specific heat measurements

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    The superconductor-insulator transition (SIT) is considered an excellent example of a quantum phase transition which is driven by quantum fluctuations at zero temperature. The quantum critical point is characterized by a diverging correlation length and a vanishing energy scale. Low energy fluctuations near quantum criticality may be experimentally detected by specific heat, cpc_{\rm p}, measurements. Here, we use a unique highly sensitive experiment to measure cpc_{\rm p} of two-dimensional granular Pb films through the SIT. The specific heat shows the usual jump at the mean field superconducting transition temperature TcmfT_{\rm c}^{\rm {mf}} marking the onset of Cooper pairs formation. As the film thickness is tuned toward the SIT, TcmfT_{\rm c}^{\rm {mf}} is relatively unchanged, while the magnitude of the jump and low temperature specific heat increase significantly. This behaviour is taken as the thermodynamic fingerprint of quantum criticality in the vicinity of a quantum phase transition.Comment: 9 pages, 5 figures, 1 tabl

    Bayesian Gene Set Analysis

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    Gene expression microarray technologies provide the simultaneous measurements of a large number of genes. Typical analyses of such data focus on the individual genes, but recent work has demonstrated that evaluating changes in expression across predefined sets of genes often increases statistical power and produces more robust results. We introduce a new methodology for identifying gene sets that are differentially expressed under varying experimental conditions. Our approach uses a hierarchical Bayesian framework where a hyperparameter measures the significance of each gene set. Using simulated data, we compare our proposed method to alternative approaches, such as Gene Set Enrichment Analysis (GSEA) and Gene Set Analysis (GSA). Our approach provides the best overall performance. We also discuss the application of our method to experimental data based on p53 mutation status

    The Higgs Mode in Disordered Superconductors Close to a Quantum Phase Transition

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    The concept of mass-generation via the Higgs mechanism was strongly inspired by earlier works on the Meissner-Ochsenfeld effect in superconductors. In quantum field theory, the excitations of longitudinal components of the Higgs field manifest as massive Higgs bosons. The analogous Higgs mode in superconductors has not yet been observed due to its rapid decay into particle-hole pairs. Following recent theories, however, the Higgs mode should decrease below the pairing gap 2Δ2\Delta and become visible in two-dimensional systems close to the superconductor-insulator transition (SIT). For experimental verification, we measured the complex terahertz transmission and tunneling density of states (DOS) of various thin films of superconducting NbN and InO close to criticality. Comparing both techniques reveals a growing discrepancy between the finite 2Δ2\Delta and the threshold energy for electromagnetic absorption which vanishes critically towards the SIT. We identify the excess absorption below 2Δ2\Delta as a strong evidence of the Higgs mode in two dimensional quantum critical superconductors.Comment: 6 pages, 3 figure

    The landscape does not care it is a landscape: A utopian pessimist journey in Kentucky.

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    These thesis and exhibition, invite the viewers to travel through different places in Central and Eastern Kentucky. The region’s landscape, like many other American landscapes, is often known to the public through the settler colonial lens—a lens that ignores Indigenous peoples’ history in the region. The work in the exhibition is a response to landscape art\u27s history and its complicity with American settler colonialism- art that was recruited to create a new identity for the settlers and for the country from the beginning of the American Colonial Project. Landscape art was a crucial part of this effort, presenting the land as an empty, God-given place for white settlers. However, not only was this land not empty but it has been occupied by Native Americans for millennia. Communities lived within the land and did not separate themselves from it. As opposed to this way of living, settler colonialism seeks to take over land and extract its resources, while trying to eliminate all Indigenous peoples. This approach has never ended and in many ways is the root of the climate and environmental crisis we live in. The exhibition offers both moments and images that appear to be more dire; others are intimate and hopeful. This contrast and tension are a reminder that while we grieve the victims and losses of colonial violence, there are many survivors. Regardless of what the future will look like, we can be inspired by the resiliency and nevertheless imagine a new world

    Seminar Users in the Arabic Twitter Sphere

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    We introduce the notion of "seminar users", who are social media users engaged in propaganda in support of a political entity. We develop a framework that can identify such users with 84.4% precision and 76.1% recall. While our dataset is from the Arab region, omitting language-specific features has only a minor impact on classification performance, and thus, our approach could work for detecting seminar users in other parts of the world and in other languages. We further explored a controversial political topic to observe the prevalence and potential potency of such users. In our case study, we found that 25% of the users engaged in the topic are in fact seminar users and their tweets make nearly a third of the on-topic tweets. Moreover, they are often successful in affecting mainstream discourse with coordinated hashtag campaigns.Comment: to appear in SocInfo 201

    Interoperability of GPON and WiMAX for network capacity enhancement and resilience

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    This paper was published in Journal of Optical Networking and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/JON/Issue.cfm. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law. Copyright Optical Society of America.The interoperability of standard WiMAX and GPON is shown to overcome the wireless spectrum congestion and provide resilience for GPON through the use of overlapping radio cells. The application of centralised control in the optical line terminal (OLT) and time division multiplexing for upstream transmission enables efficient dynamic bandwidth allocation for wireless users on a single wavelength as well as minimised optical beat interference at the optical receiver. The viability of bidirectional transmission of multiple un-coded IEEE802.16d channels by means of a single radio frequency (RF) subcarrier at transmission rates of 50 Mbits/s and 15 Mbits/s downstream and upstream respectively for distances of up to 21 km of integrated GPON and WiMAX micro-cell links is demonstrated.Peer reviewe
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