Neste trabalho foi realizado um grande levantamento de técnicas de esparsidade relacionadas a sistemas estáticos de energia elétrica. Tais técnicas visam, do ponto de vista computacional, ao aumento da eficiência na solução de rede elétrica objetivando, além da resolução em si, a redução dos requisitos de memória, armazenamento e tempo de processamento. Para tanto, uma extensa revisão bibliográfica foi compilada, apresentando um posicionamento histórico e uma ampla visão do desenvolvimento teórico. Os testes comparativos realizados para sistemas de 14, 30, 57 e 118 barras, sobre a implantação de três das técnicas mais empregadas, apontou a Bi-fatoração como tendo o melhor desempenho médio. Para sistemas pequenos, a Eliminação Esparsa e Sintética de Gauss apresentou melhores resultados. Este trabalho fornecerá subsídios conceituais e metodológicos a técnicos e pesquisadores da área. / In this work a great survey of sparsity techniques related to static systems of electric power was accomplished. Such techniques seek, for of the computational point of view, the increase of the efficiency in the solution of the electric net aiming, besides the resolution of itself, the reduction of memory requirements, the storage and time processing. For that, an extensive bibliographic review was compiled providing a historic positioning and a broad view of theoretic development. The comparative tests accomplished for systems of 14,30, 57 and 118 buses, on the implementation of three of the most employed techniques, it pointed out an bi-factorisation as best medium performance. For small systems, the sparse symmetric Gaussian elimination showed the best results. This work will supply conceptual and methodological subsidies to technicians and researchers of the area.

Σκοπός της παρούσας διατριβής είναι η κατασκευή και μελέτη συνολοθεωρητικών λύσεων της κβαντικής εξίσωσης Yang-Baxter (απεικονίσεις Yang-Baxter) και η συσχέτισή τους με την ολοκληρωσιμότητα διακριτών δυναμικών συστημάτων. Οι κατασκευές απεικονίσεων Yang-Baxter που προτείνονται προέρχονται από την αναπαραγοντοποίηση ισχυρών ζευγών Lax εξαρτώμενων από μια φασματική παράμετρο. Οι αντίστοιχοι πίνακες Lax προκύπτουν από την συμπλεκτική εμφύλλωση διωνυμικών πινάκων εφοδιασμένων με μια κατάλληλη δομή Poisson (αγκύλη Sklyanin). Στην περίπτωση των 2x2 πινάκων Lax, οι αντίστοιχες απεικονίσεις είναι συμπλεκτικές, τετράρητες και ταξινομούνται με βάση τον μεγιστοβάθμιο όρο του πίνακα Lax ως προς την ισοδυναμία απεικονίσεων Yang-Baxter. Εκφυλισμένες απεικονίσεις Yang-Baxter, οι οποίες σχετίζονται με γνωστές ολοκληρώσιμες εξισώσεις, προκύπτουν από όρια των τετράρητων (μη-εκφυλισμένων). Η σύνδεση μεταξύ απεικονίσεων Yang-Baxter και ολοκληρωσιμότητας επιτυγχάνεται θεωρώντας περιοδικά προβλήματα αρχικών τιμών σε δισδιάστατα πλέγματα. Σε κάθε απεικόνιση Yang-Baxter αντιστοιχεί μια οικογένεια αντιμεταθετικών απεικονίσεων μεταφοράς στο πλέγμα (transfer maps) που διατηρούν αναλλοίωτο το φάσμα του μονόδρομου πίνακά τους. Η αγκύλη Sklyanin εξασφαλίζει την ενέλιξη των ολοκληρωμάτων που προκύπτουν από το φάσμα του μονόδρομου πίνακα. Κατά αυτόν τον τρόπο από τις συμπλεκτικές απεικονίσεις Yang-Baxter που κατασκευάσαμε παράγονται ολοκληρώσιμες απεικονίσεις μεταφοράς. Τέλος, η μελέτη μας επεκτείνεται σε συστήματα πεπλεγμένων απεικονίσεων Yang-Baxter (entwining Yang-Baxter maps) . / The purpose of this thesis is the construction and the study of set theoretical solutions of the quantum Yang-Baxter equation (Yang-Baxter maps) and the connection with the integrability of discrete integrable systems. The constructions that we present are derived from the re-factorization of strong Lax pairs depending on a spectral parameter. The corresponding Lax matrices are obtained from the symplectic foliation of binomial matrices equipped with an appropriate Poisson bracket (Sklyanin bracket). In the case of 2x2 binomial Lax matrices, the corresponding maps are symplectic, quadrirational and can be classified with respect to the Yang-Baxter equivalence. Degenerate Yang-baxter maps constructed as limits of the quadrirational maps, are connected to known integrable equations. The connection between Yang-Baxter maps and integrability is achieved by considering periodic initial value problems on two dimensional lattices. For any Yang-Baxter map that admits a Lax matrix, there is a family of commuting transfer maps which preserve the spectrum of their monodromy matrix. The Skllyanin bracket ensures that the integrals obtained from the spectrum of the monodromy matrix are in involution. In this way, integrable transfer maps are generated from the symplectic Yang-Baxter maps that we constructed. Finally, our study is extended for systems of entwining Yang-Baxter maps.

Neste trabalho foi realizado um grande levantamento de técnicas de esparsidade relacionadas a sistemas estáticos de energia elétrica. Tais técnicas visam, do ponto de vista computacional, ao aumento da eficiência na solução de rede elétrica objetivando, além da resolução em si, a redução dos requisitos de memória, armazenamento e tempo de processamento. Para tanto, uma extensa revisão bibliográfica foi compilada, apresentando um posicionamento histórico e uma ampla visão do desenvolvimento teórico. Os testes comparativos realizados para sistemas de 14, 30, 57 e 118 barras, sobre a implantação de três das técnicas mais empregadas, apontou a Bi-fatoração como tendo o melhor desempenho médio. Para sistemas pequenos, a Eliminação Esparsa e Sintética de Gauss apresentou melhores resultados. Este trabalho fornecerá subsídios conceituais e metodológicos a técnicos e pesquisadores da área. / In this work a great survey of sparsity techniques related to static systems of electric power was accomplished. Such techniques seek, for of the computational point of view, the increase of the efficiency in the solution of the electric net aiming, besides the resolution of itself, the reduction of memory requirements, the storage and time processing. For that, an extensive bibliographic review was compiled providing a historic positioning and a broad view of theoretic development. The comparative tests accomplished for systems of 14,30, 57 and 118 buses, on the implementation of three of the most employed techniques, it pointed out an bi-factorisation as best medium performance. For small systems, the sparse symmetric Gaussian elimination showed the best results. This work will supply conceptual and methodological subsidies to technicians and researchers of the area.

Flera företag använder sig än idag av mjukvarusystem som är uppbyggda med äldre mjukvaruarkitektur som den monolitiska. Ett av dessa företag är Consid vars personalsystem är uppbyggt med det utdaterade ramverket klassisk ASP och där användargränssnitt samt logik kan direkt kommunicera med varandra. Detta medför begränsningar som uppstår till följd av brister i modularitet på grund av valet av mjukvaruarkitektur, vilket försvårar vidareutveckling och ändringar i ett system. Dessa begränsningar påverkar i sin tur parametrar som prestanda, skalbarhet, säkerhet, robusthet samt integrering med modernare tekniker.  I denna rapport presenteras en litteraturstudie samt en semistrukturerad intervjustudie, i syfte att undersöka vilka mjukvaruarkitekturer som är lämpliga att implementera vid en modernisering av en monolitisk mjukvaruarkitektur. Arbetet diskuterade också vilka utmaningar som kan uppstå vid en sådan modernisering och hur de hanteras på ett effektivt sätt. Ett bedömningsschema med önskvärda parametrar, med avseende på skalbarhet, prestanda, säkerhet och robusthet, togs fram för att underlätta avgörandet vid val av mjukvaruarkitektur. Utifrån detta, beslutades det att en prototyp med en REST-baserad arkitektur skulle implementeras och utvärderas.  Resultatet av prototypen, till följd av re-architecting, visade en ökad modularisering av mjukvaruarkitekturen. I jämförelse mot med det tidigare systemet har den nya prototypen ingen större påverkan på prestanda i form av responstid. Däremot bidrog prototypen till förbättrad skalbarhet när det gäller vidareutvecklingen av systemet, eftersom det förenklar införandet av ny funktionalitet. Prototypen hade också högre säkerhet genom att isolera lager ifrån varandra samt dölja underliggande detaljer i implementationen. Dessutom blev prototypen inte bara mer robust till följd av modulariseringen, men även enklare att utföra integrationstester samt destruktiva tester mot. / Several companies still use software systems that are built with older software architecture such as the monolithic one. One of these companies is Consid, whose personnel system is built with the outdated framework Classic ASP and where the user interface and logic can directly communicate with each other. This entails limitations that arise because of shortcomings in modularity due to the choice of software architecture, which complicates further development and changes in a system. These limitations in turn, affect parameters such as performance, scalability, security, robustness, and integration with modern technologies. In this work, a literature study was conducted as well as a semi-structured interview study in order to investigate which software architectures are suitable to implement when a modernization of a monolithic software architecture, is carried out. The work also discussed the challenges that may arise in a modernization of the software architecture and how they are handled efficiently. An assessment scheme with desirable parameters regarding scalability, performance, security, and robustness, was developed to facilitate the decision in the choice of software architecture. Based on this, it was decided that a prototype with a REST-based architecture would be implemented and evaluated. The result of the prototype, following re-architecting, showed an increased modularization of the software architecture. Compared to the previous system, the new prototype has no major impact on performance in terms of response time. However, the prototype contributed to better scalability in the further development of the system as it simplifies the introduction of new functionality. The prototype also had higher security by isolating layers from each other and hiding the underlying details in the implementation. In addition, the prototype not only became more robust because of the modularization, but also easier to perform destructive tests against.

This master's thesis describes an environment for creation and management of interactive web pages. It deals with both the structure design and the visual part. The basic idea is that the page consists of individual elements that can be arbitrarily composed together. There exist several kinds of such elements: interactive, content, database and informative elements. Furthermore, the environment includes tools for account management, access control, database administration, auditing, multilanguage support and some more.