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It s Time to Do Something: Mitigating the Negative Impacts of Computing Through a Change to the Peer Review Process
Get PDFUntersuchungen zum Rundkneten von Mikrobauteilen
Get PDFThe demand for miniature components, as well as the requirement for high functional density paired with high precision, is increasing steadily from year to year. For example, saving resources and cost-effectiveness can be mentioned as reasons for this trend. This high demand paves the way for the development of new manufacturing processes or for the research and adaptation of existing processes for the purpose of miniaturization. Due to the specific advantages, such as the generation of residual compressive stresses in the components or the ability to produce complex geometries with adapted properties, the suitability of rotary swaging for micro manufacturing has been explored in recent years. Rotary swaging is very well-established in the macro range, especially in the automotive industry, and has also been explored. However, because it is well known that scaling a process from the macro to the micro range cannot always be readily accomplished, it is of particular interest to fill the knowledge gap of downsizing related to the swaged parts. The focus of the presented investigations was the understanding of the process in general as well as the phenomenon occurring in the component, the determination of the process limits and thus the productivity and the characterization of the products. A simulation of the process with the FE method showed the complexity of the material behavior, from which, for example, explanations for the occurrence of certain types of failure or for the hardening of the components can be derived. Furthermore, an unfavorable material flow was identified as the most common cause of failure in the micro rotary swaging process. Measures to control it were developed and experimentally investigated. An increase in the output rate without significant deterioration of the component quality was a target. This work shows that rotary swaging has a high potential for micro manufacturing, since different materials, ferrous and non-ferrous metals, can be easily formed and thus very high component strengths can be achieved
Who is Going to Build the Wall? A Building Trades Crisis in the U.S.A.
Get PDFThe context of this study was to examine factors contributing to significant workforce shortages in building trades in the United States. As it is, recruitment of qualified skilled trades workers is becoming increasingly difficult due to lack of a pipeline of prospective workers, and training programs. The study assumed a theoretical inquiry approach in order to address the following three main questions: 1) What is the scope of the workforce shortage in skilled and building trades in the US? 2) What factors are recognized as contributors to the building trades workforce shortage in the US? And, 3) What strategies can be implemented to reverse building trades workforce shortages in the US? Findings affirmed that the scope of workforce shortages in skilled and building (con- struction) trades in the US is very broad and the impact is rather deep. Factors con- tributing to the shortage include: declines in high school technical education programs, which have been replaced by career academies; misconception that higher education al- ways equal higher income, but the untold story is higher debt associated with pursuing higher education; and stricter immigration laws, which are forcing potential workers out of the US. The study concluded that in order to reverse currently declining workforce trends the following six strategies should be implemented: 1) Make it a national priority, thereby appropriating adequate resources to the effort. 2) Increase the number or women and African Americans in building trades. 3) Expand apprenticeship programs. An expan- sion of both government and corporate incentives are needed to stimulate an increase in apprenticeships. 4) Reintroduce building and skilled trades programs in secondary and postsecondary schools. Growth in the number of Career Academies, and participation in them has been encouraging, yet there are not enough of them to meet the need. 5) Re-examine guest-worker programs, which are currently cumbersome for employers to participate in, and do not allow for anywhere close to the number of workers needed to meet workforce needs. 6) Change marketing of building trades from menial to meaning- ful. Many young people simply do not know that they can make a comfortable living from a career in skilled trades. They have been taught that at least a bachelor s degree is needed in order to have a successful career. This narrative has to be revised in order to create a pipeline of prospective skilled trades employees for the future
HDL-based Synthesis of Reversible Circuits : A Scalable Design Approach
Get PDFReversible computing is a promising research field due to its applications in several emerging technologies. Accordingly, several approaches for the design of reversible circuits have been introduced. Hardware Description Languages approach scales better than other methodologies, however, its main drawback is substantial amounts of additional circuit lines. This dissertation is an important step towards an elaborated scalable design flow of reversible circuits. In which, HDL-based design of reversible circuit is optimised, with line-awareness considered as the main objective. A line-aware programming style for a dedicated reversible hardware description language SyReC is proposed. Another contribution is a line-aware computation of HDL expressions. Reversible circuits' synthesis from a conventional hardware description language (VHDL) is examined. Finally, syntactical extensions to the dedicated hardware description language SyReC are suggested
Change ahead?! Status quo der Kompetenzorientierung im Land Bremen aus der Sicht von Englischlehrkräften
Get PDFThe adoption of educational standards for the first foreign language in 2004 is tied to the requirement to orient foreign language teaching towards competences. Some members of the foreign language didactics have already worked out proposals on how lessons that focus on the development of the competencies of the students could look like. However, no research has been conducted so far on how teachers deal with competence orientation in English teaching. This research gap was taken as the reason for this dissertation project - which is part of the English didactics and refers to findings of implementation and education governance research - to find out more about the English teacher's perspective on the status quo of competence based teaching in the Bundesland Bremen. In order to be able to make a statement on the status quo of competence orientation within the scope of the doctoral project, a multi-methodical, explorative access to the research field was chosen: To begin with, the field was explored with the aid of a quantitative questionnaire survey (n = 56 English teachers). This questionnaire was then followed by qualitative expert interviews (n = 7). Based on the results of the aforementioned means of exploring the field, patterns were generated that reflect how English teachers deal with competence orientation. The results show that the education plan of Bremen (the so-called Bildungsplan) and the educational standards for the first foreign language are in urgent need of revision, as the uncertainty of English teachers in dealing with competence orientation is primarily triggered by the diffuseness of the guidelines. Another important result is that - regardless of the pattern - the biggest challenge for English teachers in the implementation of competence orientation is the way grammar is taught. More research is needed to further explore and develop the aspect of the serving function of grammar. In summary, the dissertation project shows that the paradigm shift celebrated by representatives of education policy has only partially taken place from the point of view of English teachers in the state of Bremen
Dynamic Modeling and Implementation of Trajectory Optimization, Sensitivity Analysis, and Optimal Control for Autonomous Deep Space Navigation
No full textWithin this thesis, methods for on-board trajectory optimization and optimal control regarding different tasks of an autonomous deep space exploration mission are investigated. These include cruise flight maneuvers towards a small celestial body, more specifically an asteroid, operations in its vicinity, and the performance of landing procedures. Therefore, dynamic models and respective optimal control problems are formulated. The former include where appropriate the gravitational influence of the Sun, of further planets, and of the asteroid, and the effects due to solar radiation pressure. Because of the high complexity and large a priori uncertainty about asteroids as well as the limited resources on a spacecraft, high precision methods of nonlinear optimization and optimal control are necessary. In this course, optimal control problems are transcribed into large sparse nonlinear optimization problems via direct transcription techniques. Conflicting mission aims, that is, short flight times and low energy consumption, are considered within the objective functions. Additionally, an on-board capable parametric sensitivity analysis is implemented, allowing for an approximation of deviations in optimal solutions in case of perturbations within model parameters. Thus, additional stability information is provided. Furthermore, the approximation of perturbed controls can be used for real-time control in time critical situations. The results strengthen the need for trajectory optimization and sensitivity analysis as a foundation for autonomous decision making and fault detection, isolation, and recovery (FDIR) techniques regarding flight maneuvers during deep space missions. However, the field of space science is just a sample application. By changing the dynamics and model properties, the developed algorithms can easily be adapted for terrestrial applications such as autonomous driving or deep sea navigation
Faszination Kinderzeichnung : Annäherung, Adaption, Intensivierung des kindlichen Ausdrucks am Beispiel des Künstlers Paul Klee
Get PDFDie Abschlussarbeit befasst sich mit der Frage, ob es für den erwachsenen Menschen möglich wäre, zu dem eigenen kindlichen Ausdruck zurückzufinden. Besonders hervorzuheben ist hierbei die Faszination als unterstützender Faktor, die der/die Betrachter in gegenüber der Kinderzeichnung empfindet. Um eine Grundlage für das Verständnis der Kinderzeichnung zu legen, wurden authentische Beispiele in einer Kindertagesstätte gesammelt, aus denen deutlich wird, welche Entwicklungsschritte das zeichnende Kind durchläuft und durch welche Besonderheiten sich seine Kunst auszeichnet. Im fortschreitenden 20. Jahrhundert versprach sich der/die Künstler in durch die Auseinandersetzung mit der Kinderzeichnung, wieder zu seinem individuellen künstlerisch-kindlichen Ausdruck, seinen Wurzeln, zurückzufinden. Besonders der Künstler Paul Klee hat sich intensiv mit der Kunst von Kindern beschäftigt - so erarbeitete er einerseits anhand der eigenen kindlichen Biografie Ausdrucksmittel für seine Kunst, ließ sich andererseits auch von den Arbeiten seines Sohnes und denen anderer Kinder inspirieren, adaptierte und intensivierte die für Kinderzeichnungen typischen Stilelemente und entwickelte so einen besonderen Ausdruck, der die Betrachter innen auch heute noch fasziniert
EUX et NOUS La place des Autochtones dans l'enseignement de l'histoire nationale du Quebec Volume 2
Get PDFLa presente etude se presente en trois volumes. Elle analyse la place allouee a l histoire autochtone dans l enseignement scolaire et l image qu il transmet des Autochtones et de leur role dans l histoire canadienne et quebecoise. La constitution implicite ou explicite d un NOUS collectif par rapport a l AUTRE sera au centre de notre interet. Un premier volume (urn:nbn:de:gbv:46-00106629-19 http://nbn-resolving.de/urn:nbn:de:gbv:46-00106629-19) analyse les contenus et des discours des manuels d histoire, a commencer par les manuels approuves par le Ministre de l'Education, du Loisir et du Sport du Quebec du programme Histoire et education a la citoyennete au second cycle de l enseignement secondaire et les manuels actuels du primaire. Ensuite, pour saisir l evolution entre les annees 1970 et nos jours, nous procederons a l analyse des manuels les plus repandus des annees 1980 et 1990 du programme Histoire du Quebec et du Canada . Dans ce second volume, nous nous interesserons dans le detail a la perception de l histoire autochtone dans la conscience des jeunes, aussi bien francophones, anglophones et autochtones en analysant un millier de copies d eleves a travers le Quebec. Il s agira ainsi de mieux comprendre quels roles ils leur attribuent dans la trame de l histoire nationale, quelles hypotheses ils font pour combler des lacunes apparentes et comment ils construisent leur NOUS respectif, par rapport aux AUTRES. Suite aux retards dans la publication des manuels definitifs du nouveau programme Histoire du Quebec et du Canada des annees 2016-17-18, leur analyse sera reservee a un troisieme volume. Pour conclure l ensemble, le discours majoritaire dans l enseignement de l histoire nationale y sera confronte a celui de manuels d histoire autochtones concus specialement pour eux
Image Analysis via Applied Harmonic Analysis : Perceptual Image Quality Assessment, Visual Servoing, and Feature Detection
Get PDFCertain systems of analyzing functions developed in the field of applied harmonic analysis are specifically designed to yield efficient representations of structures which are characteristic of common classes of two-dimensional signals, like images. In particular, functions in these systems are typically sensitive to features that define the geometry of a signal, like edges and curves in the case of images. These properties make them ideal candidates for a wide variety of tasks in image processing and image analysis. This thesis discusses three recently developed approaches to utilizing systems of wavelets, shearlets, and alpha-molecules in specific image analysis tasks. First, a perceptual image similarity measure is introduced that is solely based on the coefficients obtained from six discrete Haar wavelet filters but yields state of the art correlations with human opinion scores on large benchmark databases. The second application concerns visual servoing, which is a technique for controlling the motion of a robot by using feedback from a visual sensor. In particular, it will be investigated how the coefficients yielded by discrete wavelet and shearlet transforms can be used as the visual features that control the motion of a robot with six degrees of freedom. Finally, a novel framework for the detection and characterization of features such as edges, ridges, and blobs in two-dimensional images is presented and evaluated in extensive numerical experiments. Here, versatile and robust feature detectors are obtained by exploiting the special symmetry properties of directionally sensitive analyzing functions in systems created within the recently introduced alpha-molecule framework
Geothermal Heat Flow in the Amundsen Sea Sector of West Antarctica
Get PDFThe ice sheet inWest Antarctica is underlain by theWest Antarctic Rift System, which yields critical geological boundary conditions. The bedrock geology and the crustal structure of the rift system may influence the dynamics of the overlying glaciers, which in turn affect the stability of the ice sheet. Previous geophysical surveys have traced the West Antarctic Rift System from the Ross Sea to the Bellingshausen Sea and compared it to other major continental rift zones, such as the East African Rift System or the Basin and Range Province. While the rift system in the Ross Sea sector is relatively well understood, the remaining part of the rift system surrounds a higher degree of uncertainty. Young, continental rift systems, such as the West Antarctic Rift System, are associated with high geothermal heat flow and elevated lithospheric geotherms. In-situ temperature observations of geothermal heat flow are extremely sparse in Antarctica, but present crucial thermal boundary conditions ice sheet models and related sea level rise predictions. Moreover, temperature measurements are urgently required to study geodynamic and tectonic processes, subglacial lakes, hydrologic networks and ecosystems beneath ice sheets, that remain largely unexplored. Indirect methods, that estimate geothermal heat flow on regional to continental scales show poor correlation, which leads to ambiguous results in e.g. ice sheet models. Scientifically, this project aims at contributing to the overall knowledge of the thermal state of the crust in the Amundsen Sea Sector. Within the context of this thesis, a novel suit of in-situ temperature measurements were collected in the Amundsen Sea Embayment during RV Polarstern expedition PS75 (2010) and PS104 (2017). A novel magnetic anomaly grid is further presented, which includes aeromagnetic data collected during RV Polarstern expedition PS104, as well as previous aeromagnetic surveys, and forms the base for investigations of the thermal state of the crust. By Curie depth estimates, based on spectral analysis of the magnetic anomaly data and numerical models in 2D and 3D, the spatial distribution of geothermal heat flow and the thermal architecture of the crust is examined. The main outcomes of the thesis are local estimates of geothermal heat flow of 60 mWm2 to 90 mWm2, which is likely biased towards higher values due to the temperature variability in the water column. Indirect estimates from numerical models in contrast point towards elevated ( 90 mWm2) and locally high ( 90 mWm2) geothermal heat flow. In summary, the findings from the current thesis represent a significant advancement towards understanding of geothermal heat flow in the Amundsen Sea Sector of West Antarctica