Dieses Manuskript entstand aus Vorlesungen über Geodätische Berechnungen an der Hochschule für Technik und Wirtschaft Dresden. Da diese Lehrveranstaltung im ersten oder zweiten Semester stattfindet, werden noch keine Methoden der höheren Mathematik benutzt. Das Themenspektrum beschränkt sich deshalb weitgehend auf elementare Berechnungen in der Ebene. Nur im Kapitel 7 kommen einige Methoden der Vektorrechnung zum Einsatz.

published_or_final_version / Electrical Engineering / Master / Master of Philosophy

Ο σκοπός της εργασίας είναι η παρουσίαση της έννοιας της συμμετρίας ως έναν μετασχηματισμό που απεικονίζει τη λύση μιας Δ.Ε. σε μια άλλη Δ.Ε. διατηρώντας αναλλοίωτη και αμετάβλητη τη μορφή της. Παρουσιάζεται επίσης η μέθοδος της αναλλοίωτης διαφόρισης και ο αλγόριθμος Lie. / -

Cyber-Physical Systems (CPSs) are defined as the combination of computational elements with physical components. Systems that require communication, computation, and control are by definition CPSs. The complexity of these systems often grows exponentially as they incorporate more elements into their design. As such, many approaches to designing CPSs revolve around the development of Domain Specific Modeling Languages (DSMLs). DSMLs drastically reduce the development time for CPSs by abstracting elements of the development process to a high level. DSMLs can be constrained in such a way that it is impossible to construct structurally invalid models of CPSs. This allows designers to think abstractly and ignore time consuming low level implementation details. However, these methods do not prevent designers from constructing systems that can be invalid in other, more dynamic, ways. That is, structural constraints on a DSML for a CPS do not prevent constraint violations where some analysis must be performed on the system to verify that the constraint has been satisfied. In the state-of-the-art, it is violations on these dynamic constraints that modelers must spend their time designing around. Dynamic constraints can be incorporated into the framework of a DSML by integrating the concepts of automatic feedback control into the DSML with model transformations. The methodology that describes this new approach to Domain Specific Modeling (DSM) is called Dynamic Constraint Feedback (DCF). At a glance: first a DSML is created for a CPS. Next, an interface is developed for two-way interaction between the DSML and external tools. Third, an expert block that can perform analysis on the models is created. The expert block is responsible for determining constraint violations and solutions. Lastly, model transformations are generated based on expert block output and applied to the existing models. This process repeats until a solution is either found or declared to be unreachable.

In this paper, the method is proposed for transforming UML class diagrams with OCL constraints to relational database schemas, having advantages over “UML Profile for Databases” models. The proposed method consists of two phases supplementing each other: metamodel based transformations and pattern-based transformations. All transformations are based on OMG official standards or RFPs (Request for Proposals) and are prepared for use in MDA (Model Driven Architecture) context. This means, that resulting models, created using the described method, are long-lasting, independent from platform and abstract enough to be independent from technology. This work covers analysis of the field of object – relational transformations, analysis of support of OCL in currently used UML tools, transformation rule sets of metamodel transformations and pattern-based transformations, a lot of examples illustrating every transformation. Metamodel transformations are designed to transform object models written in UML language to corresponding relational models: types, classes, attributes, association classes, associations to tables, columns, foreign keys and other concepts. Pattern-based transformations are designed for generating static relational concepts such as check constraints, views, stored procedures and triggers. Using the two described transformation types and the whole method described, one can generate full-fledged relational database schemas, have precise UML models and keep much more... [to full text]

In recent years, multicarrier modulation techniques have stirred great interest among engineers and researchers working in the field of telecommunications. Multicarrier systems are characterized by the fact that constellation symbols are modulated in parallel onto several distinct subcarriers. One specific form of multicarrier modulation, referred to as OFDM (orthogonal frequency division multiplexing), has been deployed in many applications, such as in wireless LAN (local area network) routers, in high-definition television tuners, and in DSL (digital subscriber line) modems. Multicarrier and OFDM systems have proved to be much more robust against impairments such as impulse noise and sudden channel fadings than their single carrier counterparts. Moreover, channel equalization in OFDM systems can be performed at a very low computational cost by a set of per-subcarrier one-tap equalizers. / Despite their many advantages, OFDM systems have a few, but important, drawbacks. In particular, OFDM relies on the inverse FFT for modulation purposes, which leads to a very poor spectral containment and a high susceptibility to narrowband noise. To mitigate this problem, we propose in this thesis to perform multicarrier modulation using a perfect reconstruction (PR) DFT filter bank instead of employing the inverse FFT. The design of such filter banks is addressed using a novel method that guarantees the PR property to be satisfied while the spectral containment is being maximized. Equalization in the proposed DFT filter bank transceiver takes advantage of the fact that the filter banks do not contribute to any distortion due to its PR nature. Two equalization schemes are presented. The first one is based on a zero-padded block linear equalization approach, and the second one utilizes a one-tap per subcarrier configuration. The estimation of the channel coefficients in the proposed transceiver is also addressed. A blind estimation method that exploits the inherent cyclostationarity of the transmitted signal is derived. Computer experiments presented in this thesis indicate that the spectral containment of the proposed PR DFT filter bank transceiver is indeed superior to that of the OFDM system. Moreover, simulations conducted in a DSL-like environment contaminated by a narrowband noise show that the achievable bit rate of the proposed transceiver is much higher than that of a conventional OFDM system.

My aim with this thesis is to use a combination of posthumanist and feminist materialist perspectives in analysing the anime film Spirited Away (2001). The analysis is organised as follows: the first chapter of the analysis deals with the notions of agency and magic. Magic is an omnipresent force in the bathhouse depicted in the film; a force that creates connections between different bodies and that also bridges the language-matter divide. By making inanimate matter come alive, magic points to a conception of life as relations rather than as possession. However, magic also reveals the hierarchies at work, as not all animate(d) beings have the capacity or the right to use it. The first chapter is followed by three chapters focused on eating, understood as a kind of intra-action between different kinds of matter. Food is, as I will show, important in the negotiations of boundaries and agency. The question of who is eating who also reveals some of the power relationships that govern the posthuman world depicted in the film. In the two last chapters of the analysis I will, so to speak, push the food plate aside in favour of other matters. The fifth chapter will focus on the physical transformations taking place in the film and how these can be interpreted from a posthumanist and materialist perspective. I will look at embodiments, using a narratologically influenced perspective that allows for corporeal ambiguities and shuns notions of bodies as fixed and clearly separate from other bodies. The discussion will continue in the final chapter where I use 'monster theory' to further examine the leakages between categories. The monstrous corresponds not necessarily to widely-spread images of monsters (known from various cultural masterplots) or to bodies that distinctly disobey the norms. The morphological diversity exhibited by the characters in the film reveals the impossibility of clearly demarcating categories and boundaries between Self and Other.

Presented work covers one of the most important areas of OMG’s model driven architecture (MDA) – problems of object model transformations. Based on research of OMG specifications and other sources, author analyzes transformation process, states importance of modeling and metamodeling for designing of UML like modeling languages. Research work describes designed metamodels of experimental modeling languages: “Entity – process”, Java metamodel and relational metamodel. Author gives a short overview of model editors for these languages, created using EMF framework tools. Based on analysis, author describes very flexible architecture of model transformation implementation, based on filter and pipes architectural pattern. Usage of this architecture gives flexibility to transformation implementation and allows easy and straightforward decomposition of transformation to separate stages. Designed filter and pipes transformation architecture was used for experimental transformation implementation. Research work presents quality and quantity based results of experimental transformations.

Darbo tikslas yra išnagrinėti renginių organizavimo problemas, sukurti Renginių organizavimo sistemą, bei naudojant konceptualaus modeliavimo metodikas atlikti modelių transformacijų tyrimą. Darbo metu buvo išnagrinėta eilė kitų panašių sistemų, ir kuriant šią sistemą buvo atsižvelgta į jų trūkumus bei privalumus. Modeliai ir modeliavimo metodai yra būdas nagrinėti ir valdyti šiuolaikinių sistemų uždavinių apimtį ir sudėtingumą naudojant įvairias abstrakcijas. Pats modelis yra tam tikra abstrakcijos rūšis, įgalinanti atvaizduoti sistemą ar jos dalį abstrakčiau, išryškinant esmines savybes, praleidžiant ar paslepiant mažiau svarbias. Sistemos projektavime buvo naudotos konceptualaus modeliavimo metodikos, kurios yra sėkmingai taikomos grafiškai atvaizduoti informacines sistemas konceptualiame lygmenyje. Vėliau taikant šias metodikas buvo atliktas eksperimentinis tyrimas su viena iš sukurtos sistemos dalių. / The object of this work is to analyze the problems of events’ organizing, and to create Events’ organizing system, that would correspond clients’ requirements, and expectations of users. During this work I explored a number of similar systems, and all their pros and cons has been taken into consideration while creating this system. Models and modeling techniques is one of the ways to analyze and control the complexity and volume of problems of modern systems using various abstraction levels. Model by itself is a certain type of abstraction that helps to visualize a system or part of it more abstractly, highlighting key features, while skipping or hiding less important ones. In the development of the system, I used methods of conceptual modeling that are successfully applied in graphic development of systems at the conceptual level. Later using these methods I did an experiment with one of the parts of the system.

Les transitions de phase dans les solides sont accompagnées de modifications particulières des propriétés thermiques, électriques, magnétiques, etc..., en plus des changements de structure cristalline; aussi les travaux entrepris à propos de ces phénomènes sont nombreux. Cependant, aucune théorie ne s'est révélée complète et satisfaisante. Il nous a semblé qu'il serait intéressant d'essayer d'approfondir ce sujet; nous avons choisi le bromure d'ammonium, les chlorures d'ammonium et de césium de symétrie cubique à basse température et qui conservent cette symétrie lors de la transformation, ceci pouvant simplifier éventuellement certaines études. Notre exposé est divisé en quatre chapitres : Dans le premier, nous avons réuni quelques notions thermodynamiques et cristallographiques connues sur les transitions de phase dans les solides. Le deuxième chapitre comprend la description de l'appareillage que nous avons utilisé, soit trois techniques principales: dilatométrie, thermoradiocristallographie et analyse thermique différentielle. Dans le troisième chapitre sont consignés nos résultats expérimentaux concernant le bromure d'ammonium, les chlorures d'ammonium et de césium. Nous avons essayé de déterminer leur température de transition et d'étudier leur comportement au moment de leur changement de structure. Le dernier chapitre est un essai d'interprétation de nos résultats expérimentaux, sous les aspects cinétique, thermodynamique et structural. Certaines explications avancées dans ce chapitre apparaitront d'ailleurs insuffisantes.