137 research outputs found
Ray class fields of global function fields with many rational places
A general type of ray class fields of global function fields is investigated.
The systematic computation of their genera leads to new examples of curves over
finite fields with comparatively many rational points.Comment: Latex2e, 27 pages, 20 tables, revised version as submitted to Acta
Arithmetic
Legendre elliptic curves over finite fields
We show that every elliptic curve over a finite field of odd characteristic
whose number of rational points is divisible by 4 is isogenous to an elliptic
curve in Legendre form, with the sole exception of a minimal respectively
maximal elliptic curve. We also collect some results concerning the
supersingular Legendre parameters
An experiment to compare the combined array and the product array for robust parameter design
The paper reports a robust parameter design experiment, where we have used Taguchi's product array and a combined array simultaneously. This was done as part of a research project dealing with experimental design to optimise the process of sheet metal spinning. We found that the classical analysis of the product array identified a control factor, which has an influence on the variance of the response. There were no indications of this effect in the combined array. A confirmation experiment supports the finding that this factor in fact is a control factor. It seems that its effect on the variance is due to several two- and three-factor interactions that were not large enough to be found in the combined array. In the authors' opinion this shows that the use of a product array and the classical analysis provides robustness against imprecise model assumptions. --Robust parameter design,noise factor,design factor,signal to noise ratio,product array,combined array,interaction plot
Optimisation of the shear forming process by means of multivariate statistical methods
Shear forming is a versatile process for manufacturing complex lightweight components which are required in increasing numbers by many different industries. Inherent advantages of the process are simple tooling, low tool costs, good external and internal surface quality, close dimensional accuracy, and good mechanical properties of the components. In times of free market economy, it is necessary to on the one hand fulfill the increasing demands toward the quality characteristics and on the other hand to reduce the development time needed to manufacture such a high quality component. Since shear forming is a complex and sensitive process in terms of deformation characteristics this is not an easy task. To assess the overall quality of a component several, mutually contradictory, quality characteristics have to be considered simultaneously. While conventionally each characteristic is considered separately, in this paper, a statistical approach is presented which copes with the above mentioned demands and provides the opportunity for an efficient, multivariate optimisation of the process. With a minimum of statistically planned experiments, mathematical models are derived which describe the influence of the machine parameters and their interactions on quantitative as well as qualitative component characteristics. A multivariate optimisation procedure based on the concept of desirabilities is used to find the best compromise between the mutually contradictory quality characteristics. With this statistical approach a workpiece for electrical industry is manufactured which requires a very good surface quality and close geometrical tolerances. --Shear forming,experimental design,multivariate optimisation,high voltage divider
An Experiment to Compare the Combined Array and the Product Array for Robust Parameter Design
The paper reports a robust parameter design experiment, where we have used Taguchi's product array and a combined array simultaneously. This was done as part of a research project dealing with experimental design to optimise the process of sheet metal spinning. We found that the classical analysis of the product array identified a control factor, which has an influence on the variance of the response. There were no indications of this effect in the combined array. A confirmation experiment supports the finding that this factor in fact is a control factor. It seems that its effect on the variance is due to several two- and three-factor interactions that were not large enough to be found in the combined array. In the authors' opinion this shows that the use of a product array and the classical analysis provides robustness against imprecise model assumptions
Optimisation of the shear forming process by means of multivariate statistical methods
Shear forming is a versatile process for manufacturing complex lightweight components which are
required in increasing numbers by many different industries. Inherent advantages of the process are
simple tooling, low tool costs, good external and internal surface quality, close dimensional accuracy,
and good mechanical properties of the components.
In times of free market economy, it is necessary to on the one hand fulfill the increasing demands toward
the quality characteristics and on the other hand to reduce the development time needed to manufacture
such a high quality component. Since shear forming is a complex and sensitive process in terms of
deformation characteristics this is not an easy task.
To assess the overall quality of a component several, mutually contradictory, quality characteristics
have to be considered simultaneously. While conventionally each characteristic is considered
separately, in this paper, a statistical approach is presented which copes with the above mentioned
demands and provides the opportunity for an efficient, multivariate optimisation of the process. With a
minimum of statistically planned experiments, mathematical models are derived which describe the
influence of the machine parameters and their interactions on quantitative as well as qualitative
component characteristics. A multivariate optimisation procedure based on the concept of desirabilities
is used to find the best compromise between the mutually contradictory quality characteristics.
With this statistical approach a workpiece for electrical industry is manufactured which requires a very
good surface quality and close geometrical tolerances
FĂŒr einen Angewandten Utopismus
Utopien beschreiben andere VerhĂ€ltnisse, um reale Gesellschaften zu kritisieren oder Alternativen zu ihnen zu entwerfen. Sie können ernst sein oder spielerisch. Alle Formen und RealitĂ€tsbezĂŒge des Utopischen haben ihren Ort. Aber wir möchten fĂŒr eine bestimmte Spielart plĂ€dieren: Angewandten Utopismus
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Development of a Domain-Specific Ontology to Support Research Data Management for the Tailored Forming Technology
The global trend towards the comprehensive digitisation of technologies in product manufacturing is leading to radical changes in engineering processes and requires a new extended understanding of data handling. The amounts of data to be considered are becoming larger and more complex. Data can originate from process simulations, machines used or subsequent analyses, which together with the resulting components serve as a complete and reproducible description of the process. Within the Collaborative Research Centre "Process Chain for Manufacturing of Hybrid High Performance Components by Tailored Forming", interdisciplinary work is being carried out on the development of process chains for the production of hybrid components. The management of the generated data and descriptive metadata, the support of the process steps and preliminary and subsequent data analysis are fundamental challenges. The objective is a continuous, standardised data management according to the FAIR Data Principles so that process-specific data and parameters can be transferred together with the components or samples to subsequent processes, individual process designs can take place and processes of machine learning can be accelerated. A central element is the collaborative development of a domain-specific ontology for a semantic description of data and processes of the entire process chain
Taking appreciation to heart: appreciation at work and cardiovascular risk in male employees.
INTRODUCTION
While perceived appreciation at work has been associated with self-reported health and wellbeing, studies considering biological health markers are lacking. In this study, we investigated whether appreciation at work would relate to coronary heart disease (CHD) risk as well as the specificity of this proposed association.
METHODS
Our study comprised a total of 103 male participants, including apparently healthy, medication-free, non-smoking men in the normotensive to hypertensive range (nâ=â70) as well as medicated hypertensive and CHD patients (nâ=â33). CHD risk was assessed by blood pressure [mean arterial pressure (MAP)], the diabetes marker glycated hemoglobin A1c (HbA1c), blood lipids [total cholesterol (TC)/high-density lipoprotein-cholesterol (HDL-C) ratio], coagulation activity (D-dimer and fibrinogen), and inflammation [interleukin (IL)-6, tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP)]. Perceived appreciation at work, as well as potentially confounding psychological factors (social support, self-esteem, and work strain due to a lack of appreciation), were measured by self-report questionnaires.
RESULTS
We found higher appreciation at work to relate to lower overall composite CHD risk (p'sââ€â0.011) and, in particular, to lower MAP (p'sââ€â0.007) and lower blood lipids (p'sââ€â0.031) in medication-free participants as well as all participants. This overall association was independent of confounding factors, including related psychological factors (p'sââ€â0.049).
DISCUSSION
Our findings indicate that appreciation at work might be an independent health-promoting resource in terms of CHD risk. Implications include that encouraging appreciation at work may help reduce the development and progression of CHD
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Creation of a Knowledge Space by Semantically Linking Data Repository and Knowledge Management System - a Use Case from Production Engineering
The seamless documentation of research data flows from generation, processing, analysis, publication, and reuse is of utmost importance when dealing with large amounts of data. Semantic linking of process documentation and gathered data creates a knowledge space enabling the discovery of relations between steps of process chains. This paper shows the design of two systems for data deposit and for process documentation using semantic annotations and linking on a use case of a process chain step of the Tailored Forming Technology
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