The moderating effect of social capital and environmental dynamism on the link between entrepreneurial orientation and resource acquisition

This study attempts to define the four constructs identified in the title and examine patterns of interaction among them. It begins by demonstrating that entrepreneurial orientation influences resource acquisition. It then puts forward a set of parameters to assess the degree to which two factors identified as social capital and environmental dynamism affect an entrepreneurial orientation resource acquisition equation. The study finds that there are relationships between all four of the constructs, but in three propositions developed in the course of discussion it puts forward issues that may be clarified by future research, which from various angles could show how entrepreneurially oriented firms react differently from more established firms in terms of their acquisition of resources and interaction with social capital and environmental dynamism. © 2011 Springer Science+Business Media B.V

Statistical models for time sequences data mining

In this paper, we present an adaptive modelling technique for studying past behaviors of objects and predicting the near future events. Our approach is to define a sliding window (of different window sizes) over a time sequence and build autoregression models from subsequences in different windows. The models are representations of past behaviors of the sequence objects. We can use the AR coefficients as features to index subsequences to facilitate the query of subsequences with similar behaviors. We can use a clustering algorithm to group time sequences on their similarity in the feature space. We can also use the AR models for prediction within different windows. Our experiments show that the adaptive model can give better prediction than non-adaptive models.published_or_final_versio

Entrepreneurial Orientation and Organizational Learning on SMEs' Innovation

Entrepreneurial orientation (EO) is a driver of firms’ innovation. The phenomenon of EO as a prerequisite for innovation has become a central focus of corporate entrepreneurship literature. Despite an abundance of research suggesting that innovation capability contributes to SMEs’ performance, little is known how dimensions of EO specifically influence SMEs’ innovation. Furthermore, although prior research has examined various factors that influence the EO– innovation relationship, few studies have address views how organizational learning influences the EO-innovation relationship in the SMEs context. Based on the literature review, our study attempts to fill this gap by postulating that entrepreneurial innovativeness, proactiveness and risk-taking are related to SMEs’ innovation and that organizational learning positively moderates the EO–innovation relationships

Nonlinear lightwave circuits in chalcogenide glasses fabricated by ultrafast laser

This Letter reports a nonlinear directional waveguide coupler written by ultrafast laser in gallium lanthanum sulfide chalcogenide glass. The nonlinear waveguide device is tested with laser pulses input in two orthogonal polarizations, and all optical switching at 1040 nm between the two coupled waveguides is observed at a peak fluence of 16 GW?cm2. The spectra and autocorrelation measurement from the waveguide outputs show dominant nonlinear effects and negligible dispersion for light propagation in both channels. © 2014 Optical Society of America

Nonlinear optical localization in embedded chalcogenide waveguide arrays

We report the nonlinear optical localization in an embedded waveguide array fabricated in chalcogenide glass. The array, which consists of seven waveguides with circularly symmetric cross sections, is realized by ultrafast laser writing. Light propagation in the chalcogenide waveguide array is studied with near infrared laser pulses centered at 1040 nm. The peak intensity required for nonlinear localization for the 1-cm long waveguide array was 35.1 GW/cm 2, using 10-nJ pulses with 300-fs pulse width, which is 70 times lower than that reported in fused silica waveguide arrays and with over 7 times shorter interaction distance. Results reported in this paper demonstrated that ultrafast laser writing is a viable tool to produce 3D all-optical switching waveguide circuits in chalcogenide glass. © 2014 Author(s)

Ultrafast laser fabrication of Bragg waveguides in chalcogenide glass

Bragg waveguides are fundamental components in photonic integrated circuits and are particularly interesting for mid-IR applications in high index, highly nonlinear materials. In this work, we present Bragg waveguides fabricated in bulk chalcogenide glass using an ultrafast laser. Waveguides with near circularly symmetric cross sections and low propagation loss are obtained through spatial and temporal beam shaping. Using a single-pass technique, the waveguide and Bragg structure are formed at the same time. First through sixth order gratings with strengths of up to 25 dB are realized, and performance is evaluated based on the modulation duty cycle of the writing beam. © 2014 Optical Society of America

A Deep Cascade of Convolutional Neural Networks for MR Image Reconstruction

The acquisition of Magnetic Resonance Imaging (MRI) is inherently slow. Inspired by recent advances in deep learning, we propose a framework for reconstructing MR images from undersampled data using a deep cascade of convolutional neural networks to accelerate the data acquisition process. We show that for Cartesian undersampling of 2D cardiac MR images, the proposed method outperforms the state-of-the-art compressed sensing approaches, such as dictionary learning-based MRI (DLMRI) reconstruction, in terms of reconstruction error, perceptual quality and reconstruction speed for both 3-fold and 6-fold undersampling. Compared to DLMRI, the error produced by the method proposed is approximately twice as small, allowing to preserve anatomical structures more faithfully. Using our method, each image can be reconstructed in 23 ms, which is fast enough to enable real-time applications

Application of new method spinning Nu-TorqueTM yarn for weaving

2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Backward bifurcation, equilibrium and stability phenomena in a three-stage extended BRSV epidemic model

In this paper we consider the phenomenon of backward bifurcation in epidemic modelling illustrated by an extended model for Bovine Respiratory Syncytial Virus (BRSV) amongst cattle. In its simplest form, backward bifurcation in epidemic models usually implies the existence of two subcritical endemic equilibria for R 0 < 1, where R 0 is the basic reproductive number, and a unique supercritical endemic equilibrium for R 0 > 1. In our three-stage extended model we find that more complex bifurcation diagrams are possible. The paper starts with a review of some of the previous work on backward bifurcation then describes our three-stage model. We give equilibrium and stability results, and also provide some biological motivation for the model being studied. It is shown that backward bifurcation can occur in the three-stage model for small b, where b is the common per capita birth and death rate. We are able to classify the possible bifurcation diagrams. Some realistic numerical examples are discussed at the end of the paper, both for b small and for larger values of b