The First Differential of the Functor "Algebraic K-Theory of Spaces"

In his "Algebraic K-theory of topological spaces II" Waldhausen proved that his functor A(X) splits: There is a canonical map from the stable homotopy of X which has a retraction up to weak equivalence. We adapt Waldhausen's proof to obtain a calculation of the Differential (in the sense of Goodwillie's "Calculus I") of A(X) at any path-connected base space.Comment: The calculation of the differential in Section 7 contains a mistake and it is not clear if the statement hold

An architecture for the automated detection of textual indicators of reflection

Manual annotation of evidence of reflection expressed in texts is time consuming, especially as fine-grained models of reflection require extensive training of coders, otherwise resulting in low inter-coder reliability. Automated reflection detection provides a solution to this problem. Within this paper, a new basic architecture for detecting evidence of reflection is proposed that allows for automated marking up of written accounts of certain, observable elements of reflection. Furthermore, three promising example annotators of elements of reflection are identified, implemented, and demonstrated: detecting reflective keywords, premise and conclusions of arguments, and questions. It appears that automated detection of reflections bears the potential to support learning with technology at least on three levels: it can foster creating awareness of the reflectivity of own writings, it can help in becoming aware of reflective writings of others, and it can make visible reflective writings of learning networks as a whole

Keywords of written reflection - a comparison between reflective and descriptive datasets

This study investigates reflection keywords by contrasting two datasets, one of reflective sentences and another of descriptive sentences. The log-likelihood statistic reveals several reflection keywords that are discussed in the context of a model for reflective writing. These keywords are seen as a useful building block for tools that can automatically analyse reflection in texts

Comparing Direct and Indirect Taxation: The Influence of Framing on Tax Compliance

Standard theory of the optimal mix of direct and indirect taxation implicitly assumes that compliance is not influenced by the framing of the taxes. According to our findings, this is not the case. Using an experimental approach, we examine whether framing the tax payment decision as income tax or consumption tax influences compliance. We find that median compliance is 10.2 percentage points higher in the income tax framing. Further, we find that subjects' reaction to a change in tax rates is comparable, but reaction towards a change in detection rates is higher in the consumption tax scheme. We conclude that behavioral patterns should be taken into account when drawing conclusions about the direct-indirect tax mixComparative analysis of tax systems ; behavioral public finance ; optimal tax mix ; noncompliance ; framing

A Bramble-Pasciak conjugate gradient method for discrete Stokes equations with random viscosity

We study the iterative solution of linear systems of equations arising from stochastic Galerkin finite element discretizations of saddle point problems. We focus on the Stokes model with random data parametrized by uniformly distributed random variables and discuss well-posedness of the variational formulations. We introduce a Bramble-Pasciak conjugate gradient method as a linear solver. It builds on a non-standard inner product associated with a block triangular preconditioner. The block triangular structure enables more sophisticated preconditioners than the block diagonal structure usually applied in MINRES methods. We show how the existence requirements of a conjugate gradient method can be met in our setting. We analyze the performance of the solvers depending on relevant physical and numerical parameters by means of eigenvalue estimates. For this purpose, we derive bounds for the eigenvalues of the relevant preconditioned sub-matrices. We illustrate our findings using the flow in a driven cavity as a numerical test case, where the viscosity is given by a truncated Karhunen-Lo\`eve expansion of a random field. In this example, a Bramble-Pasciak conjugate gradient method with block triangular preconditioner outperforms a MINRES method with block diagonal preconditioner in terms of iteration numbers.Comment: 19 pages, 1 figure, submitted to SIAM JU

Collective Intelligence Analytics Dashboard Usability Evaluation

Online deliberations can reach a size where it is not possible anymore to quickly infer what is going on in a debate. This report presents results from the usefulness and usability evaluation of visualisations that aid the sense-making of large debates. Based on the results of the evaluations we prepared a set of recommendations to inform CI tool providers about the usefulness and usability of each visualisation