К вопросу о дистанционном обучении в аэрокосмической отрасли

Данная статья содержит информацию о возможности применения дистанционного обучения в образовательном процессе для получения степени бакалавра или магистра, либо для получения сертификата о прохождении образовательного курса в области аэрокосмической инженерии. Также рассматриваются преимущества и недостатки электронного обучения в аэрокосмической сфере. Проводится сравнительный анализ различных программ дистанционного обучения в зарубежных странах по основным критериям: стоимость обучения, продолжительность и содержание курса, требования кстуденту и т.д. Кроме того, изучена распростран?нность онлайн обучения в аэрокосмической отрасли в России и выявлены возможные проблемы реализации дистанционного обучения в аэрокосмической инженерии.This article contains an information about the possibilities of applying distance learning in the educational process in order to earn bachelor's degree or master's degree, or to obtain a certificate of passing the educational course in the field of aerospace engineering. The advantages and disadvantages of e-learning in the aerospace field are also mentioned. Comparative analysis of various distance learning programs in foreign countries was made according to the main criteria: tuition fee, duration and course content, student requirements, etc. In addition, the prevalence of online learning in the aerospace industry in Russia and possible problems of implementation ofdistance learning in aerospace engineering are covered

MAC schemes on triangular Delaunay meshes

We study two classical generalized MAC schemes on unstructured triangular Delaunay meshes for the incompressible Stokes and Navier-Stokes equations and prove their convergence for the first time. These generalizations use the duality between Voronoi and triangles of Delaunay meshes, in order to construct two staggered discretization schemes. Both schemes are especially interesting, since compatible finite volume discretizations for coupled convection-diffusion equations can be constructed which preserve discrete maximum principles. In the first scheme, called tangential velocity scheme, the pressures are defined at the vertices of the mesh, and the discrete velocities are tangential to the edges of the triangles. In the second scheme, called normal velocity scheme, the pressures are defined in the triangles, and the discrete velocities are normal to the edges of the triangles. For both schemes, we prove the convergence in $L^2$ for the velocities and the discrete rotations of the velocities for the Stokes and the Navier-Stokes problem. Further, for the normal velocity scheme, we also prove the strong convergence of the pressure in $L^2$. Linear and nonlinear numerical examples illustrate the theoretical predictions

Convergence of a finite volume scheme to the eigenvalues of a Schrödinger operator

We consider the approximation of a Schrödinger eigenvalue problem arising from the modeling of semiconductor nanostructures by a finite volume method in a bounded domain $OmegasubsetR^d$. In order to prove its convergence, a framework for finite dimensional approximations to inner products in the Sobolev space $H^1_0(Omega)$ is introduced which allows to apply well known results from spectral approximation theory. This approach is used to obtain convergence results for a classical finite volume scheme for isotropic problems based on two point fluxes, and for a finite volume scheme for anisotropic problems based on the consistent reconstruction of nodal fluxes. In both cases, for two- and three-dimensional domains we are able to prove first order convergence of the eigenvalues if the corresponding eigenfunctions belong to $H^2(Omega)$. The construction of admissible meshes for finite volume schemes using the Delaunay-Voronoï method is discussed. As numerical examples, a number of one-, two- and three-dimensional problems relevant to the modeling of semiconductor nanostructures is presented. In order to obtain analytical eigenvalues for these problems, a matching approach is used. To these eigenvalues, and to recently published highly accurate eigenvalues for the Laplacian in the L-shape domain, the results of the implemented numerical method are compared. In general, for piecewise $H^2$ regular eigenfunctions, second order convergence is observed experimentally

Convergence of a finite volume scheme to the eigenvalues of a Schrödinger operator

We consider the approximation of a Schr{\"o}dinger eigenvalue problem arising from the modeling of semiconductor nanostructures by a finite volume method in a bounded domain $\Omega\subset\R^d$. In order to prove its convergence, a framework for finite dimensional approximations to inner products in the Sobolev space $H^1_0(\Omega)$ is introduced which allows to apply well known results from spectral approximation theory. This approach is used to obtain convergence results for a classical finite volume scheme for isotropic problems based on two point fluxes, and for a finite volume scheme for anisotropic problems based on the consistent reconstruction of nodal fluxes. In both cases, for two- and three-dimensional domains we are able to prove first order convergence of the eigenvalues if the corresponding eigenfunctions belong to $H^2(\Omega)$. The construction of admissible meshes for finite volume schemes using the Delaunay-Vorono\"i method is discussed. As numerical examples, a number of one-, two- and three-dimensional problems relevant to the modeling of semiconductor nanostructures is presented. In order to obtain analytical eigenvalues for these problems, a matching approach is used. To these eigenvalues, and to recently published highly accurate eigenvalues for the Laplacian in the L-shape domain, the results of the implemented numerical method are compared. In general, for piecewise $H^2$ regular eigenfunctions, second order convergence is observed experimentally

A finite volume scheme for nonlinear parabolic equations derived from one-dimensional local Dirichlet problems

In this paper, we propose a new method to compute the numerical flux of a finite volume scheme, used for the approximation of the solution of parabolic partial differential equation with nonlinear diffusion and convection terms a 1D, 2D or 3D domain. The nonlinear diffusion term be bounded away from zero except a finite number of values. The method is based on the solution, at each interface between two control volumes, of a nonlinear elliptic two point boundary value problem derived from the original equation with Dirichlet boundary conditions given by the values of the discrete approximation in both control volumes. We prove the existence of a solution to this two point boundary value problem. We show that the expression for the numerical flux can be yielded without referring to this solution. Furthermore, we prove that the so designed finite volume scheme has the expected stability properties and that its solution converges to the weak solution of the continuous problem. Numerical results show the increase of accuracy due to the use of this scheme, compared to some other schemes

Unterstützung und Implikationen von Gruppen-Awareness bei einer kollaborativen Websuche

In den letzten Jahren wurden zahlreiche Anwendungen entwickelt, um kollaborative Websuchen über größere Entfernungen hinweg zu unterstützen. Es wurde gezeigt, dass Gruppen-Awareness einen bedeutenden Einfluss auf den Erfolg entsprechender Anwendungen hat. Obwohl kollaborative Websuchen häufig auch an einem lokalen Ort stattfinden, wurde dieses Szenario in aktuellen Arbeiten deutlich weniger betrachtet. In dieser Masterarbeit wird der Einfluss von Gruppen-Awareness auf lokale kollaborative Websuche in Kleingruppen untersucht. Ein Schwerpunkt liegt dabei auf der Unterscheidung zwischen Anwendungen für lokale Websuche und solchen, bei denen sich die Teilnehmer*innen an unterschiedlichen Orten befinden. Bestehende Anwendungen für kollaborative Websuchen werden vorgestellt und eingeordnet. Basierend auf einem neu vorgestellten Prototypen wird eine Pilotstudie in einer Multi-Device-Umgebung durchgeführt. Die Studie zeigt, dass sich die Bereitstellung von Aktivitätsdaten positiv auf die Arbeitsergebnisse von lokalen kollaborativen Websuchen auswirken kann. Zudem wurden Schwachstellen und Verbesserungsmöglichkeiten für die bestehenden Funktionen identifiziert.:1 Einleitung 1 1.1 Motivation 1 1.2 Zielstellung und Aufbau 2 2 Forschungsstand 5 2.1 Kollaboration 5 2.2 Gruppen-Awareness 7 2.3 Kollaborative Websuche 9 2.3.1 Sensemaking 11 2.3.2 Lokale Websuche 13 2.3.3 Suchstrategien 16 2.4 Cross-Device-Websuche 18 2.5 Anwendungen für kollaborative Websuche 19 2.5.1 Anwendungen für Websuchen an unterschiedlichen Orten 20 2.5.2 Anwendungen für lokale Websuchen 25 2.6 Zusammenfassung des Forschungsstandes 28 3 CoFind 31 3.1 Ansichten und Funktionen 32 3.1.1 Sidebar 33 3.1.2 Detailansicht 37 3.1.3 Modi 39 3.1.4 Einschränkungen 41 3.2 Logging 42 3.2.1 Nutzerbezogene Logs 43 3.2.2 Laufzeitbezogene Logs 43 3.3 Architektur 44 3.3.1 Kommunikation und Websockets 44 3.3.2 Client 44 3.3.3 Server 45 3.3.4 Datenbank 46 3.3.5 Konfiguration 47 3.4 Zusammenfassung 48 4 Nutzerstudie 51 4.1 Aufgabenstellung 51 4.2 Studiendesign 52 4.2.1 Aufbau 52 4.2.2 Geräte und Software 53 4.2.3 Anforderungen an die Teilnehmer 55 4.2.4 Methodik 56 4.3 Datenerhebung 57 5 Ergebnisse 63 5.1 Teilnehmer 63 5.2 Arbeitsergebnisse 65 5.3 Gruppenarbeit und Kollaboration 66 5.3.1 Raumnutzung 66 5.3.2 Arbeitsphasen 67 5.3.3 Kommunikation 69 5.3.4 Nutzung der Hardware 70 5.4 CoFind und Gruppen-Awareness 72 5.4.1 Allgemeiner Eindruck 72 5.4.2 Nutzung des CoFind-Plug-ins 73 5.4.3 Sidebar 76 5.4.4 Detailansicht 78 5.4.5 Sicherheit 79 5.5 Diskussion 79 5.5.1 Bewertung des Studiendesigns 80 5.5.2 Bewertung des CoFind-Plug-ins 81 5.5.3 Diskussion der Forschungsfragen 84 6 Fazit 87 6.1 Zusammenfassung 87 6.2 Ausblick 88 Literatur 91 A Anhang 103In recent years, numerous applications have been developed to support collaborative web search over large distances. A major impact of group awareness on the success of such applications has been shown. Although collaborative web search often occurs co-located, this scenario is underrepresented in recent studies. This master thesis investigates the influence of group awareness on co-located collaborative web search in small groups is investigated. ThIt focuses on a distinction between tools for remote and co-located web search. Existing applications for collaborative web search are presented and classified. Based on a new prototype a pilot study in a multi device environment is conducted. The study shows a positive effect on co-located collaborative web search by providing activity data among groups. In addition, weaknesses and opportunities to improve existing functions are shown.:1 Einleitung 1 1.1 Motivation 1 1.2 Zielstellung und Aufbau 2 2 Forschungsstand 5 2.1 Kollaboration 5 2.2 Gruppen-Awareness 7 2.3 Kollaborative Websuche 9 2.3.1 Sensemaking 11 2.3.2 Lokale Websuche 13 2.3.3 Suchstrategien 16 2.4 Cross-Device-Websuche 18 2.5 Anwendungen für kollaborative Websuche 19 2.5.1 Anwendungen für Websuchen an unterschiedlichen Orten 20 2.5.2 Anwendungen für lokale Websuchen 25 2.6 Zusammenfassung des Forschungsstandes 28 3 CoFind 31 3.1 Ansichten und Funktionen 32 3.1.1 Sidebar 33 3.1.2 Detailansicht 37 3.1.3 Modi 39 3.1.4 Einschränkungen 41 3.2 Logging 42 3.2.1 Nutzerbezogene Logs 43 3.2.2 Laufzeitbezogene Logs 43 3.3 Architektur 44 3.3.1 Kommunikation und Websockets 44 3.3.2 Client 44 3.3.3 Server 45 3.3.4 Datenbank 46 3.3.5 Konfiguration 47 3.4 Zusammenfassung 48 4 Nutzerstudie 51 4.1 Aufgabenstellung 51 4.2 Studiendesign 52 4.2.1 Aufbau 52 4.2.2 Geräte und Software 53 4.2.3 Anforderungen an die Teilnehmer 55 4.2.4 Methodik 56 4.3 Datenerhebung 57 5 Ergebnisse 63 5.1 Teilnehmer 63 5.2 Arbeitsergebnisse 65 5.3 Gruppenarbeit und Kollaboration 66 5.3.1 Raumnutzung 66 5.3.2 Arbeitsphasen 67 5.3.3 Kommunikation 69 5.3.4 Nutzung der Hardware 70 5.4 CoFind und Gruppen-Awareness 72 5.4.1 Allgemeiner Eindruck 72 5.4.2 Nutzung des CoFind-Plug-ins 73 5.4.3 Sidebar 76 5.4.4 Detailansicht 78 5.4.5 Sicherheit 79 5.5 Diskussion 79 5.5.1 Bewertung des Studiendesigns 80 5.5.2 Bewertung des CoFind-Plug-ins 81 5.5.3 Diskussion der Forschungsfragen 84 6 Fazit 87 6.1 Zusammenfassung 87 6.2 Ausblick 88 Literatur 91 A Anhang 10

The Numerical Simulation Application for Fire-Tube Boiler Heating Surface Safety Evaluation

The numerical simulation is applied for fire-tube boiler heating surface safety estimation. Thermal processes in an inflatable fire-tube furnace during its emergency operation were simulated using the finite volume method with Euler approximation and the implicit pressure based algorithm. Study results reproduce failures connected with increasing of impasse aerodynamic resistance. The method of these failures prediction is suggested. Simulation has shown that entering the amount of coolant into combustion volume results in burner fan incapability to overcome the impasse resistance of the furnace. The simulation results are visually confirmed during the inspection of emergency boilers

Fracture strength of different soldered and welded orthodontic joining configurations with and without filling material

The aim of this study was to compare the mechanical strength of different joints made by conventional brazing, TIG and laser welding with and without filling material. Five standardized joining configurations of orthodontic wire in spring hard quality were used: round, cross, 3 mm length, 9 mm length and 7 mm to orthodontic band. The joints were made by five different methods: brazing, tungsten inert gas (TIG) and laser welding with and without filling material. For the original orthodontic wire and for each kind of joint configuration or connecting method 10 specimens were carefully produced, totalizing 240. The fracture strengths were measured with a universal testing machine (Zwick 005). Data were analyzed by ANOVA (p=0.05) and Bonferroni post hoc test (p=0.05). In all cases, brazing joints were ruptured on a low level of fracture strength (186-407 N). Significant differences between brazing and TIG or laser welding (