Auslander-Reiten theory for simply connected differential graded algebras

Peter Jorgensen introduced the Auslander-Reiten quiver of a simply connected Poincare duality space. He showed that its components are of the form ZA_infty and that the Auslander-Reiten quiver of a d-dimensional sphere consists of d-1 such components. In this thesis we show that this is the only case where finitely many components appear. More precisely, we construct families of modules, where for each family, each module lies in a different component. Depending on the cohomology dimensions of the differential graded algebras which appear, this is either a discrete family or an n-parameter family for all n.Comment: 58 pages, doctoral thesis University of Paderborn (2007

The endofinite spectrum of a tame algebra

AbstractLet R be a ring. Based on indecomposable endofinite R-modules and characters that were introduced by Crawley-Boevey [Modules of finite length over their endomorphism ring, in: S. Brenner, H. Tachikawa (Eds.), Representations of Algebras and Related Topics, in: London Math. Soc. Lecture Note Ser., vol. 168, 1992, pp. 127–184], we define the endofinite spectrum of the ring R. We compute this spectrum in some examples and study the behaviour of it under certain functors, with the objective of understanding the endofinite spectrum of tame algebras. Furthermore, we show that the endomorphism ring of a minimal point of the endofinite spectrum is a skew field. Hence the minimal points belong to the Cohn spectrum, as studied by Ringel [The spectrum of a finite dimensional algebra, in: Proc. Conf. on Ring Theory, Dekker, New York, 1979, pp. 535–598], which in turn is a subset of the endofinite spectrum. Finally, we introduce the normalised endofinite spectrum

Neural Message Passing with Edge Updates for Predicting Properties of Molecules and Materials

Neural message passing on molecular graphs is one of the most promising methods for predicting formation energy and other properties of molecules and materials. In this work we extend the neural message passing model with an edge update network which allows the information exchanged between atoms to depend on the hidden state of the receiving atom. We benchmark the proposed model on three publicly available datasets (QM9, The Materials Project and OQMD) and show that the proposed model yields superior prediction of formation energies and other properties on all three datasets in comparison with the best published results. Furthermore we investigate different methods for constructing the graph used to represent crystalline structures and we find that using a graph based on K-nearest neighbors achieves better prediction accuracy than using maximum distance cutoff or the Voronoi tessellation graph

Task design for Engineering Mathematics: process, principles and products

International audienceWe present and analyse principles and process employed at the Danish Technical University to use authentic problems from engineering (APE) in a first year mathematics course, along with some of the products (actual student assignments)

Business Student Computer Self-Efficacy: Ten Years Later

This study analyzes computer self-efficacy for two independent samples of students enrolled in an introduction to information systems course in 1996 and 2006. We administered two validated and frequently employed measures of general computer self-efficacy to each group of students and collected demographic and computer-use data. Our findings demonstrate that the 2006 students reported significantly more computer experience, used computers much more frequently, and took significantly more core courses that require computer use than their 1996 counterparts. This experience, however, did not translate into significantly higher computer self-efficacy scores, and female students in both groups had significantly lower scores than male students. Even more surprising, after controlling for gender, class level, computer experience, and frequency of computer use, we observed that computer self-efficacy was significantly lower for the 2006 students than the 1996 students. This article discusses the implications of these findings for information systems educators

TEN YEARS LATER: CHANGES IN BUSINESS STUDENT COMPUTING EFFICACY

Two independent samples of students enrolled in a typical introduction to Information Systems course at a Midwestern university were surveyed in 1996 and 2006 to determine if business student computing efficacy changed over this ten-year period. Two computer self-efficacy (CSE) scales were administered to each sample and demographic data collected. The initial analysis of this research in progress data suggests that while students in 2006 report significantly more computer experience, use computers much more frequently, and take significantly more core courses that require computer use, this experience has not translated into significantly higher CSE scores. The implications of these preliminary findings for Information Systems educators are discussed

Matching Nondeterministic Services with Operating Guidelines

Interorganizational cooperation is more and more organized by the paradigm of services. The service-oriented architecture (SOA) provides a general framework for service interaction. It describes three roles, service provider, service requester, and service broker, together with the operations publish, find, and bind. We provide a formal method based on nondeterministic automata to model services and their interaction. We suggest operating guidelines as a convenient and intuitive artifact to realize publish. In our approach, the find operation reduces to a matching problem between the requester’s service and operating guidelines. In this paper, matching of deterministic as well as nondeterministic automata with operating guidelines is presented

Brake tests to evaluate the human behaviour at different brake pedal characteristics

-Brake-by-wire represents the replacement of traditional brake components such as pumps, hoses, fluids, brake boosters, and tandem master cylinders by electronic sensors and actuators. The different design of these brake concepts poses new challenges for the automotive industry with regard to availability and fallback levels in comparison to standard conventional brake systems. In order to evaluate this, the was investigated during a static vehicle braking simulator test. Participants modes: normal brake function, booster breakdown and brake circuit failure. The interpretation of these results and designed driver warning approach fed into a coordinated driver warning and information concept adapted to the brake failure is helpful safe stop