Narrow Results

We derive a class of analytical solutions and a dual formulation of a scalar two-space-dimensional quasi-variational inequality problem in applied superconductivity. We approximate this formulation by a fully practical finite element method based on the lowest order Raviart–Thomas element, which yields approximations to both the primal and dual variables (the magnetic and electric fields). We prove the subsequence convergence of this approximation, and hence prove the existence of a solution to both the dual and primal formulations, for strictly star-shaped domains. The effectiveness of the approximation is illustrated by numerical examples with and without this domain restriction.

We recall a recently introduced mixed formulation of thin film magnetization problems for type-II superconductors written in terms of two variables, the electric field and the magnetization function, see [Electric field formulation for thin film magnetization problems, Supercond. Sci. Technol.25 (2012) 104002]. A finite element approximation, , based on this mixed formulation, involving the lowest-order Raviart–Thomas element for approximating the electric field, was also introduced in [Electric field formulation for thin film magnetization problems, Supercond. Sci. Technol.25 (2012) 104002]. Here h, τ are the spatial and temporal discretization parameters, and with p-1 the value of power in the current–voltage relation characterizing the superconducting material. In this paper, we establish well-posedness of , and prove convergence of the unique solution of to a solution of the power law model (Q_r), for a fixed r > 1, as h, τ → 0. In addition, we prove convergence of a solution of (Q_r) to a solution of the critical state model (Q), as r → 1. Hence, we prove existence of solutions to (Q_r), for a fixed r > 1, and (Q). Finally, numerical experiments are presented.

In this work, merging ideas from compatible discretisations and polyhedral methods, we construct novel fully discrete polynomial de Rham sequences of arbitrary degree on polygons and polyhedra. The spaces and operators that appear in these sequences are directly amenable to computer implementation. Besides proving the exactness, we show that the usual three-dimensional sequence of trimmed Finite Element (FE) spaces forms, through appropriate interpolation operators, a commutative diagram with our sequence, which ensures suitable approximation properties. A discussion on reconstructions of potentials and discrete $L^2$-products completes the exposition.

Mixed Methods for Establishing Content Validity: A Value-Added Approach?

Data Science Driving Innovation.

We explore the relationship between firms’ mobile money use and their productivity using a sample of 994 formal and 1,499 informal, predominantly micro-, small- and medium firms from Zambia, Mozambique and Zimbabwe. Our findings reveal a positive and statistically significant relationship between mobile money use and labor productivity for informal firms. The effect also appears to be stronger for female-led than for male-led informal firms, suggesting that mobile money could be a valuable tool to promote gender equity in Africa’s informal sector. In contrast, for formal firms, the effect vanishes once all relevant controls are accounted for. Thus, for formal firms, mobile money may be insufficient to overcome the impediments of their business environments in Africa. Further, a complementary fsQCA reveals configurations of conditions that appear important for informal firms to truly benefit from the productivity enhancing potential of mobile money. The combination of founders’ education, firms’ location, their sector and their use of traditional bank accounts appear particularly crucial. The fsQCA findings give additional nuance to our regression results. Overall, our findings suggest that firms more exposed to transaction costs benefit more from mobile money.

Despite the calls for a broader methodological base, the technology management and the forecasting literature remain short of studies synthesising quantitative and qualitative methods. This paper addresses this gap by employing a mixed method approach to study the case of Taxol, a revolutionary drug developed to fight ovarian and breast cancer. The paper shows in detail how a data mining-based network model can be synthesised with qualitatively created event narrative to understand the development of a technology and its ecosystem. As a result, the paper shows an npartite network of Taxol drug ecosystem containing over 4,000 nodes and 11,000 edges. The network enables decision makers to understand the process, interaction of actors and lock-in mechanism in the process of technological development.

Previous studies often assume that business model innovation (BMI) is reflected in an entrepreneurial business model design. We assume that business model reconfiguration (BMR) takes place in more nuanced types and does not always lead to (radical) BMI. By undertaking a mixed methods study with 213 respectively 16 SMEs from the electronic industry, we uncover six basically different types of BMRs and discuss their performance implications. By this, we shape the current understanding of BMR and shed light on variety and implications of different types of BMRs. Our configuration study indicates that firms achieve superior performance when implementing a radically new business model reflected in a new configuration of all three components of the business model: value creation, value proposition, and value capture. Second, BMR can take place in types where only some parts of the business model are extensively changed, while others are only slightly adapted.

This study bridges occupational health and innovation management by proposing psychosocial safety climate (PSC) as a key precondition for employee-driven innovation (EDI). EDI emphasises employees’ unique potential to generate and implement innovative ideas, with conducive working conditions, particularly those supporting psychological health, being crucial. Using a mixed-method explanatory design, the research draws on survey data from 19 work teams ($n=317$) and five in-depth interviews with managers to explore the relationship between PSC and EDI. Findings show that all four PSC domains — support and commitment, priority, communication, and involvement — significantly influence EDI. The study highlights how PSC leadership and communication about worker welfare play a critical role, offering groundbreaking empirical evidence linking PSC and EDI.

The incompressible miscible displacement problem in porous media is modeled by a coupled system of two nonlinear partial differential equations, the pressure–velocity equation and the concentration equation. In this paper, we present a mixed finite volume element method (FVEM) for the approximation of the pressure–velocity equation and a standard FVEM for the concentration equation. A priori error estimates in L^∞(L²) are derived for velocity, pressure and concentration. Numerical results are presented to substantiate the validity of the theoretical results.

Mixed methods research is becoming increasingly articulated, attached to research practice, and recognized as the third major research approach or research paradigm, along with qualitative research and quantitative research. Inquiry and investigation about problems of an interdisciplinary and multidisciplinary domain, such as library and information science studies require decision to be taken about an appropriate research design. In making such a decision, the researcher must tacitly assume a philosophical point of view or a research paradigm. There are four research paradigms which construct the basis of the selection of research methodology and research methods designs. These paradigms include: a) positivism, b) interpretivism, c) critical theory, and d) post-structuralism (Bazargan, 2007). Positivism is the basis of quantitative research method, and of the qualitative research methods are the three paradigms mentioned above (namely; interpretivism, critical theory, and post-structuralism). Because of the nature and complexity of problems in library and information science settings and also the newly matters evolved in this multidisciplinary field, such as information technologies, digital libraries and so on, neither of the quantitative nor qualitative research methods, alone, are able to investigate problems pertaining to them thoroughly. Therefore, researchers of this domain require have a shift toward applying a combination of quantitative and qualitative research methods designs that is named mixed methods research. In this article, first of all we concisely review the philosophical point of views (paradigms) which construct the basis of research methods. Thereafter history and the characteristics of mixed methods research will be reviewed. Finally, applications of mixed methods research in the library and information science (LIS) are discussed.

In this paper, we present and discuss the so-called hybridizable discontinuous Galerkin (HDG) methods. The discontinuous Galerkin (DG) methods were originally devised for numerically solving linear and then nonlinear hyperbolic problems. Their success prompted their extension to the compressible Navier-Stokes equations – and hence to second-order elliptic equations. The clash between the DG methods and decades-old, well-established finite element methods resulted in the introduction of the HDG methods. The HDG methods can be implemented more efficiently and are more accurate than all previously known DG methods; they represent a competitive alternative to the well established finite element methods. Here we show how to devise and implement the HDG methods, argue why they work so well and prove optimal convergence properties in the framework of diffusion and incompressible flow problems. We end by briefly describing extensions to other continuum mechanics and fluid dynamics problems.