2,052 research outputs found
Using Peer-to-Peer Technology for Knowledge Sharing in Communities of Practices
Communities of Practices (CoPs) are informal structures within organizations that bind people together through informal relationships and the sharing of expertise and experience. As such, they are effective tools for the creation and sharing of organizational knowledge, and, increasingly, organizations are adopting them as part of their knowledge management strategies. In this paper, we examine the knowledge sharing characteristics and roles of CoPs and develop a peer-to-peer knowledge sharing architecture that matches the behavioral characteristics of the members of the CoPs. We also propose a peer-to-peer knowledge sharing tool called KTella that enables members of CoPs to voluntarily share and retrieve knowledge more effectively
What we need: Project managers` evaluation of top management actions required for software development projects
Web 2.0 is now an important internet application because of the integration of social interaction and
web technologies. Previous information system studies usually specified their research context as a
utilitarian system or hedonic system and the results were concluded within one specific system type.
Web 2.0 application provides a flexible environment for different kinds of user motivations that can be
used for utilitarian or hedonic purpose. This study extended the Technology Acceptance Model (TAM)
by introducing a moderating factor into the model, in order to study usersâ behavioral intentions in a
Web 2.0 environment. We designed two task types of user motivation and conducted our experiment on
two Web 2.0 websites. According to the PLS (Partial Least Squares) analysis, this study demonstrated
that utilitarian and hedonic purposes had a moderating effect on the relationship between perceived
belief and user attitude as well as the relationship between perceived information quality and perceived
belief in the Web 2.0 application. The relationship between perceived usefulness and attitude was
stronger in the utilitarian user motivation; whereas the relationship between perceived ease of use and
attitude was stronger when the user had hedonic motivation to use the Web 2.0 application. We also
found that perceived information quality had significant impact on the perceived usefulness and
perceived ease of use
Exploring An Individualâs Intention to Use Blogs: The Roles of Social, Motivational and Individual Factors
Blogs are a new type of media for social interaction; they have become very popular, and have shown their influence throughout our society. However, little is known about what motivates an individual to participate in blogging activities. This study aims to explore how an individual\u27s intention is influenced by social, motivational and individual factors. A survey, involving 283 subjects, was conducted to examine the proposed model. The results revealed that personal innovativeness in the domain of information technology (PIIT), perceived usefulness and perceived enjoyment have direct impacts on a persons\u27 intent to use blogs. On the other hand, factors such as subjective norms and blog self-efficacy influence an individual\u27s motivational factors; these factors, in turn, influence an individual\u27s behavioral intention in regard to blog usage. The findings of this study not only contribute to a theoretical building of those factors that effect blog usage, but also provide implications to practitioners for understanding and promoting blog usage
Interfacial effects on the polarization of films
By considering an interfacial layer between the electrode and the
() layer, the polarization and the hysteresis behavior of
film are simulated. It is found that the non-ferroelectric interface will
increase the coercive field, and remarkably suppress the polarization of the
ultrathin film under low applied fields. Due to the competition between the
interfacial effect and the internal compressive stress, the maximum
polarization on the P-E loop of a film can be independent on the film
thickness under an adequate applied field.Comment: 3 pages, 2 figure
Nanoscale modification of porous gelatin scaffolds with chondroitin sulfate for corneal stromal tissue engineering
Recent studies reflect the importance of using naturally occurring biopolymers as three-dimensional corneal keratocyte scaffolds and suggest that the porous structure of gelatin materials may play an important role in controlling nutrient uptake. In the current study, the authors further consider the application of carbodiimide cross-linked porous gelatin as an alternative to collagen for corneal stromal tissue engineering. The authors developed corneal keratocyte scaffolds by nanoscale modification of porous gelatin materials with chondroitin sulfate (CS) using carbodiimide chemistry. Scanning electron microscopy/energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy showed that the amount of covalently incorporated polysaccharide was significantly increased when the CS concentration was increased from 0% to 1.25% (w/v). In addition, as demonstrated by dimethylmethylene blue assays, the CS content in these samples was in the range of 0.078â0.149 nmol per 10 mg scaffold. When compared with their counterparts without CS treatment, various CS-modified porous gelatin membranes exhibited higher levels of water content, light transmittance, and amount of permeated nutrients but possessed lower Youngâs modulus and resistance against protease digestion. The hydrophilic and mechanical properties of scaffolds modified with 0.25% CS were comparable with those of native corneas. The samples from this group were biocompatible with the rabbit corneal keratocytes and showed enhanced proliferative and biosynthetic capacity of cultured cells. In summary, the authors found that the nanoscale-level modification has influence on the characteristics and cell-material interactions of CS-containing gelatin hydrogels. Porous membranes with a CS content of 0.112 Âą 0.003 nmol per 10 mg scaffold may hold potential for use in corneal stromal tissue engineering
Microscopic theory of quantum dot interactions with quantum light: local field effect
A theory of both linear and nonlinear electromagnetic response of a single QD
exposed to quantum light, accounting the depolarization induced local--field
has been developed. Based on the microscopic Hamiltonian accounting for the
electron--hole exchange interaction, an effective two--body Hamiltonian has
been derived and expressed in terms of the incident electric field, with a
separate term describing the QD depolarization. The quantum equations of motion
have been formulated and solved with the Hamiltonian for various types of the
QD excitation, such as Fock qubit, coherent fields, vacuum state of
electromagnetic field and light with arbitrary photonic state distribution. For
a QD exposed to coherent light, we predict the appearance of two oscillatory
regimes in the Rabi effect separated by the bifurcation. In the first regime,
the standard collapse--revivals phenomenon do not reveal itself and the QD
population inversion is found to be negative, while in the second one, the
collapse--revivals picture is found to be strongly distorted as compared with
that predicted by the standard Jaynes-Cummings model. %The model developed can
easily be extended to %%electromagnetic excitation. For the case of QD
interaction with arbitrary quantum light state in the linear regime, it has
been shown that the local field induce a fine structure of the absorbtion
spectrum. Instead of a single line with frequency corresponding to which the
exciton transition frequency, a duplet is appeared with one component shifted
by the amount of the local field coupling parameter. It has been demonstrated
the strong light--mater coupling regime arises in the weak-field limit. A
physical interpretation of the predicted effects has been proposed.Comment: 14 pages, 7 figure
An Efficient Alternating Riemannian/Projected Gradient Descent Ascent Algorithm for Fair Principal Component Analysis
Fair principal component analysis (FPCA), a ubiquitous dimensionality
reduction technique in signal processing and machine learning, aims to find a
low-dimensional representation for a high-dimensional dataset in view of
fairness. The FPCA problem involves optimizing a non-convex and non-smooth
function over the Stiefel manifold. The state-of-the-art methods for solving
the problem are subgradient methods and semidefinite relaxation-based methods.
However, these two types of methods have their obvious limitations and thus are
only suitable for efficiently solving the FPCA problem in special scenarios.
This paper aims at developing efficient algorithms for solving the FPCA problem
in general, especially large-scale, settings. In this paper, we first transform
FPCA into a smooth non-convex linear minimax optimization problem over the
Stiefel manifold. To solve the above general problem, we propose an efficient
alternating Riemannian/projected gradient descent ascent (ARPGDA) algorithm,
which performs a Riemannian gradient descent step and an ordinary projected
gradient ascent step at each iteration. We prove that ARPGDA can find an
-stationary point of the above problem within
iterations. Simulation results show that,
compared with the state-of-the-art methods, our proposed ARPGDA algorithm can
achieve a better performance in terms of solution quality and speed for solving
the FPCA problems.Comment: 5 pages, 8 figures, submitted for possible publicatio
Control-Data Separation and Logical Condition Propagation for Efficient Inference on Probabilistic Programs
We introduce a novel sampling algorithm for Bayesian inference on imperative
probabilistic programs. It features a hierarchical architecture that separates
control flows from data: the top-level samples a control flow, and the bottom
level samples data values along the control flow picked by the top level. This
separation allows us to plug various language-based analysis techniques in
probabilistic program sampling; specifically, we use logical backward
propagation of observations for sampling efficiency. We implemented our
algorithm on top of Anglican. The experimental results demonstrate our
algorithm's efficiency, especially for programs with while loops and rare
observations.Comment: 11 pages with appendice
Crosstalk between transcription factors and microRNAs in human protein interaction network
<p>Abstract</p> <p>Background</p> <p>Gene regulatory networks control the global gene expression and the dynamics of protein output in living cells. In multicellular organisms, transcription factors and microRNAs are the major families of gene regulators. Recent studies have suggested that these two kinds of regulators share similar regulatory logics and participate in cooperative activities in the gene regulatory network; however, their combinational regulatory effects and preferences on the protein interaction network remain unclear.</p> <p>Methods</p> <p>In this study, we constructed a global human gene regulatory network comprising both transcriptional and post-transcriptional regulatory relationships, and integrated the protein interactome into this network. We then screened the integrated network for four types of regulatory motifs: single-regulation, co-regulation, crosstalk, and independent, and investigated their topological properties in the protein interaction network.</p> <p>Results</p> <p>Among the four types of network motifs, the crosstalk was found to have the most enriched protein-protein interactions in their downstream regulatory targets. The topological properties of these motifs also revealed that they target crucial proteins in the protein interaction network and may serve important roles of biological functions.</p> <p>Conclusions</p> <p>Altogether, these results reveal the combinatorial regulatory patterns of transcription factors and microRNAs on the protein interactome, and provide further evidence to suggest the connection between gene regulatory network and protein interaction network.</p
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