Organizational Behavior: Production of Knowledge for Action in the World of Practice

If a policy is a solution, “actionable knowledge is the actual behavior required to implement the solution

Boundary-layer equations in generalized curvilinear coordinates

A set of higher-order boundary-layer equations is derived valid for three-dimensional compressible flows. The equations are written in a generalized curvilinear coordinate system, in which the surface coordinates are nonorthogonal; the third axis is restricted to be normal to the surface. Also, higher-order viscous terms which are retained depend on the surface curvature of the body. Thus, the equations are suitable for the calculation of the boundary layer about arbitrary vehicles. As a starting point, the Navier-Stokes equations are derived in a tensorian notation. Then by means of an order-of-magnitude analysis, the boundary-layer equations are developed. To provide an interface between the analytical partial differentiation notation and the compact tensor notation, a brief review of the most essential theorems of the tensor analysis related to the equations of the fluid dynamics is given. Many useful quantities, such as the contravariant and the covariant metrics and the physical velocity components, are written in both notations

The spatially nonuniform convergence of the numerical solution of flows

The spatial distribution of the numerical disturbances that are generated during the numerical solution of a flow is examined. It is shown that the distribution of the disturbances is not uniform. In regions where the structure of a flow is simple, the magnitude of the generated disturbances is small and their decay is fast. However, in complex flow regions, as in separation and vortical areas, large magnitude disturbances appear and their decay may be very slow. The observed nonuniformity of the numerical disturbances makes possible the reduction of the calculation time by application of what may be called the partial-grid calculation technique, in which a major part of the calculation procedure is applied in selective subregions, where the velocity disturbances are large, and not within the whole grid. This technique is expected to prove beneficial in large-scale calculations such as the flow about complete aircraft configurations at high angle of attack. Also, it has been shown that if the Navier-Stokes equations are written in a generalized coordinate system, then in regions in which the grid is fine, such as near solid boundaries, the norms become infinitesimally small, because in these regions the Jacobian has very large values. Thus, the norms, unless they are unscaled by the Jacobians, reflect only the changes that happen at the outer boundaries of the computation domain, where the value of the Jacobian approaches unity, and not in the whole flow field

Multivariate Hawkes Processes for Large-scale Inference

In this paper, we present a framework for fitting multivariate Hawkes processes for large-scale problems both in the number of events in the observed history $n$ and the number of event types $d$ (i.e. dimensions). The proposed Low-Rank Hawkes Process (LRHP) framework introduces a low-rank approximation of the kernel matrix that allows to perform the nonparametric learning of the $d^2$ triggering kernels using at most $O(ndr^2)$ operations, where $r$ is the rank of the approximation ($r \ll d,n$). This comes as a major improvement to the existing state-of-the-art inference algorithms that are in $O(nd^2)$. Furthermore, the low-rank approximation allows LRHP to learn representative patterns of interaction between event types, which may be valuable for the analysis of such complex processes in real world datasets. The efficiency and scalability of our approach is illustrated with numerical experiments on simulated as well as real datasets.Comment: 16 pages, 5 figure

What Makes a Good Plan? An Efficient Planning Approach to Control Diffusion Processes in Networks

In this paper, we analyze the quality of a large class of simple dynamic resource allocation (DRA) strategies which we name priority planning. Their aim is to control an undesired diffusion process by distributing resources to the contagious nodes of the network according to a predefined priority-order. In our analysis, we reduce the DRA problem to the linear arrangement of the nodes of the network. Under this perspective, we shed light on the role of a fundamental characteristic of this arrangement, the maximum cutwidth, for assessing the quality of any priority planning strategy. Our theoretical analysis validates the role of the maximum cutwidth by deriving bounds for the extinction time of the diffusion process. Finally, using the results of our analysis, we propose a novel and efficient DRA strategy, called Maximum Cutwidth Minimization, that outperforms other competing strategies in our simulations.Comment: 18 pages, 3 figure

Learning for a Change: Exploring the Relationship Between Education and Sustainable Development

Whether we view sustainable development as our greatest challenge or a subversive litany, every phase of education is now being urged to declare its support for education for sustainable development (ESD). In this paper, we explore the ideas behind ESD and, building on work by Foster and by Scott and Gough, we argue that it is necessary now to think of two complementary approaches: ESD 1 and ESD 2. We see ESD 1 as the promotion of informed, skilled behaviours and ways of thinking, useful in the short-term where the need is clearly identified and agreed, and ESD 2 as building capacity to think critically about what experts say and to test ideas, exploring the dilemmas and contradictions inherent in sustainable living. We note the prevalence of ESD 1 approaches, especially from policy makers; this is a concern because people rarely change their behaviour in response to a rational call to do so, and more importantly, too much successful ESD 1 in isolation would reduce our capacity to manage change ourselves and therefore make us less sustainable. We argue that ESD 2 is a necessary complement to ESD 1, making it meaningful in a learning sense. In this way we avoid an either-or debate in favour of a yes-and approach that constantly challenges us to understand what we are communicating, how we are going about it and, crucially, why we are doing it in the first place

Advancing task involvement, intrinsic motivation and metacognitive regulation in physical education classes: the self-check style of teaching makes a difference

It was hypothesized that “self-check” style of teaching would be more preferable in terms of creating a mastery-oriented climate, and promoting adaptive achievement goals, intrinsic motivation and metacognitive activity in physical education classes. Two hundred seventy-nine (N = 269) 6-grade students were randomly divided into two groups that were taught four consecutive physical education lessons of the same content following either “practice” or “self-check” styles of teaching respectively. Students responded on questionnaires prior and after the intervention. Results revealed significant interactions between groups and measurements. Students in the “self-check” style group scored higher in scales measuring mastery-oriented climate, mastery goal, intrinsic motivation and metacognitive processes and lower in scales measuring performance-goals and performance-oriented motivational climate. These results underscore the importance of using styles of teaching that enhance opportunities for deep cognitive processing and promote mastery-goals and mastery-oriented climates