Thèses sur le sujet « MKC »

Three-dimensional mathematical problems of the interaction between thermoelastic and scalar oscillation fields are considered in a general anisotropic case. An elastic structure is assumed to be a bounded homogeneous anisortopic body occupying domain $\Omega^+\sub\R^3$ , where the thermoelastic field is defined, while in the physically anisotropic unbounded exterior domain $\Omega^-=\R^3\\ \overline{\Omega^+}$ there is defined the scalar field. These two fields satisfy the differential equations of steady state oscillations in the corresponding domains along with the transmission conditions of special type on the interface $\delta\Omega^{+-}$. Uniqueness and existence theorems, for the non-resonance case, are proved by the reduction of the original interface problems to equivalent systems of boundary pseudodifferential equations ($\Psi DEs$) . The invertibility of the corresponding matrix pseudodifferential operators ($\Psi DO$) in appropriate functional spaces is shown on the basis of generalized Sommerfeld-Kupradze type thermoradiation conditions for anisotropic bodies. In the resonance case, the co-kernels of the $\Psi DOs$ are analysed and the efficent conditions of solvability of the transmission problems are established.

Some yeast strains secrete extracellular polypeptide toxins known to have potential growth inhibitory activity on other sensitive yeast genera but are immune to their own toxins. These yeast strains are termed as killer yeasts and their toxins are designated as killer proteins or killer toxins. Killer phenotypes are classified into 11 typical types (K1-K11). The toxic actions of yeast killer proteins on sensitive cells show differences and one of the most important toxic actions involves the selective functional damage by hydrolyzing major cell wall components. Because mammalian cells lack a cell wall, novel highly selective antifungals tend to be harmless to people by targeting important cell wall components specific to fungi. We have previously characterized the K9 type yeast killer protein isolated from Hansenula mrakii. This protein is stable at pH and temperature values appropriate for its medical usage. Antifungal activity of this protein was tested against 23 human pathogenic yeast and 9 dermathophyte strains. Pathogenic yeast strains found to be susceptible and both the MIC and MFC values ranged from 0.25 to 8 µ
g/ml except C. parapsilosis and C guilliermondii isolates. 9 dermatophyte strains were not susceptible to this protein and MICs were >
64 µ
g/ml. According to the cell killing analysis toxin activity starts within the first 4 hours and complete cell death was observed for the 4, 8 and 16 times the MIC concentrations at 24 hour. The results obtained from this study might make the potential use of this protein possible as a selective antimycotic agent.

In der Entwicklung der numerischen Simulation im Laufe der letzten Jahre ist ein deutlicher Trend zur Konsolidierung tu beobachten. Neben der wirtschaftlichen Konsolidierung der Anbieter - letztendlich immer weniger Anbieter, die immer mehr anbieten • gibt es noch die technische Konsolidierung der Softwarelösungen. Das Stichwort ist Integration mit der Motivation, verschiedene Solver-Disziplinen unter einem gemeinsamen Dach zu vereinigen. Der Nutzer soll wenn möglich nur noch ein Tool benutzen, das alles kann. Das ist ein ambitioniertes Ziel und technisch in nächster Zeit nicht umsetzbar, da die Unterschiede in den Lösungsansåtzen unterschiedliche Datenmodelle verlangen. Daher ist als ObergangsIOsung die Co-Simulation das Mittel der Wahl. Damit sind verschiedene Solver gemeint, die über entsprechende Schnittstellen reibungslos und vor allem ohne Nutzerinteraktion miteinander kommunizieren, um so ihre volle Leistung zu entfalten. Auf diesem Gebiet wurden in den letzten Jahren deutliche Fortschritte erzielt. MSC Software bringt nun die Möglichkeiten technologisch auf ein neues Level. Der Vortrag zeigt den konzeptionellen Ansatz, den MSC verfolgt und schrittweise umsetzt. Gezeigt werden die Vorteile in der Anwendung für den Nutzer, aber auch die Limitationen, derer man sich immer bewusst sein muss. Mit konkreten Beispielen aus der Praxis werden die Vorteile der Co-Simulation untermauert. Der Fokus des Vortrages liegt auf den Möglichkeiten, die sich für dynamische Systeme aus der Co-Simulation ergeben und wie die traditionellen Grenzen der Mehrkörpersimulation überwunden werden können: Zum einen durch Kopplung mit nichtlinearer FEM aber auch mit CFO. Inhaltlich soll der Vortrag bestenfalls den Vorstellungshorizont der Zuhörer erweitern. in jedem Fall aber konkret belegen, wo die Co-Simulation bessere Ergebnisse erzielt als die herkömmliche, auf einen Solver beschränkte Vorgehensweise.

The generalized radiation conditions at infinity of Sommerfeld-Kupradze type are established in the theory of thermoelasticity of anisotropic bodies. Applying the potential method and the theory of pseudodifferential equations on manifolds the uniqueness and existence theorems of solutions to the basic three-dimensional exterior boundary value problems are proved and representation formulas of solutions by potential type integrals are obtained.

Tesis para optar al grado de Magíster en Ciencias de la Ingeniería, Mención Eléctrica
{El presente proyecto de tesis consiste en la implementación de un Rectificador controlado basado en un Convertidor Multinivel Modular (Modular Multilevel Converter en inglés). Este proyecto se encuentra dentro del marco del proyecto FONDECYT: 1440337 Modular Multilevel Converter Technologies for High Power Drives (Aplicaciones de Convertidores Modulares Multinivel para accionamientos de alta potencia) el cual tiene por objetivo principal el estudio de estrategias de control para Convertidores Multinivel Modulares (comunmente abreviado como MMC o $M^2C$ por sus siglas en inglés) en accionamientos eléctricos, lo cual es un gran desafío ya que contempla la operación de estos en condiciones no usuales, tales como frecuencia variable (incluyendo las bajas) y tensión variable (tanto en los lados de alterna como de continua). La topología propuesta en dicho proyecto es el convertidor M2C back to back, que consiste en la conexión de 2 convertidores modulares por el enlace de continua, dejando los lados de alterna como puertos de entrada y/o salida para la conexión con la máquina y la red. En una etapa anterior ya se implementó el conversor del lado de la máquina, trabajo realizado Mauricio Espinoza en marco de su doctorado y expuesto en n publicaciones. El presente trabajo de tesis pretende aportar con la implementación del convertidor del lado de la red para así completar el convertidor Back to Back. Las primeras publicaciones relacionadas con el MMC realizan un modelado por fase, el cual es más simple e intuitivo, no obstante, conlleva desventajas asociadas como el acople en los lazos de control, que dificulta el diseño de los controladores y afecta a la dinámica del sistema. en los últimos 2 años se han desarrollado modelos desacoplados, los cuales por medio de transformadas permiten obtener 3 subsistemas independientes. Una característica del modelamiento transformado es que permite plantear distintas estrategias de control, dependiendo de cuales flujos de potencia se utilizan para balancear la energía entre las ramas del convertidor. Si bien algunas estrategias ya están planteadas, han sido aplicadas en distintas condiciones por lo que no se pueden comparar sus resultados. Todas las estrategias obtenidas se deducen de la linealización del modelo del convertidor, por lo que asumen pequeñas desviaciones en torno a un punto de operación. El principal problema de esto es que al encenderse el convertidor los voltajes en condensadores son igual a cero, por lo que debe realizarse un proceso de precarga para llevar los voltajes al punto de operación. Si bien la estrategia más popular y simple publicada es la precarga natural, esta no puede ser utilizada en este proyecto ya que por seguridad la lógica de los submódulos se encarga de negar las acciones de control entre los semiconductores, también se descartan los métodos que incluyen electrónica adicional en los módulos, dejando la opción de estudio entre las estrategias de selección y precarga controlada para este trabajo. Los aportes realizados por este trabajo son los siguientes: primero es la construcción y puesta en marcha del rectificador MMC ocupando modulación PS-PWM, el cual posteriormente servirá para futuros trabajos, tanto solo como en conexión Back to Back, el segundo aporte es la implementación y validación experimental de las posibles estrategias de control lineal en el convertidor, junto con el análisis de sus ventajas y desventajas en operación de rectificador.

This diploma thesis deals with an application of the finite element method on elastohydrodynamic (EHD) lubrication simulations. Commercially available software COMSOL is used for the computation, while two different modules for modeling EHD lubrication are described in a detail. Firstly, a new approach using the module Thin-Film Flow is developed, considering and describing some limitations of this approach. This is the very first published work dealing complex with EHD simulation in Thin-Film Flow module. In the second part of the thesis, there was created a model of line contact using the module for the introduction of partial differential equations (PDE). The model is partially verified with available works for different values of the input parameters. Subsequently, the velocity effect of the contact surfaces on the pressure and the lubricant thickness in contact is analyzed. Finally, the last part is examines the influence of the values of some parameters on the final value of the contact pressure and the lubricant thickness, as well as on numerical stability of the entire model.

This thesis deals with the comparison of alternative models of the simplified joints used in the FEM models of complex models with detailed joint details. This is essentially a screw connection with dowel bolt and standard bolt, weld connection "T" and overlap weld connection. Individual connections are compared in the simulation results of matching models.

Práce na téma: Hospodaření a veřejná moc hledá příčiny dluhů státu a nachází je v absenci odpovědnosti v procesu přijímání zákonů, a dále v naprostém zmatení nad pravým významem pojmů. hospodaření, arbitráže, dluhy, veřejné zakázky, regulace, hodnoty, veřejná moc, politika, filozofie, zákonodárství, odpovědnost, stát, trh

Hidrótropos são uma classe de compostos, que em alta concentração, aumentam a solubilidade de uma variedade de compostos hidrofóbicos em água. A principal propriedade dos hidrótropos está relacionada a MHC (concentração hidrotrópica mínima) na qual os hidrótopos começam a agregar. Neste trabalho, uma série de compostos aromáticos que mostram o efeito hidrotrópico foram usados: xileno sulfonato de sódio, salicilato de sódio, p-tolueno sulfonato de sódio, benzoato de sódio e estireno sulfonato de sódio. Diferentes técnicas foram utilizadas para avaliar a MHC, tais como, condutividade, tensão superficial, espalhamento de luz, viscosidade e fluorescência. A espectroscopia de fluorescência foi utilizada para determinar por sonda interna e externa , o grupo fenil do anel dos compostos, é utilizada como uma sonda fluorescente interna. A contribuição da intensidade dos monômeros e excímeros (Iaggr/Imonomol) foram determinados e o pireno foi utilizado como uma sonda externa determinando as intesidades relativas I1/I3. Foi observado que os valores de MHC determinados pelos diferentes métodos são concordantes entre si. O método baseado na intensidade de emissão agregado / monomol, apresentou vantagens quando comparado com outros métodos, pois não requer o uso de sondas ou aditivos, que proporcionariam a desagregação dos hidrótropos.
Hydrotropes are a class of compounds that, at a high concentration, enhance the solubility of a variety of hydrophobic compounds in water. The main property of the hydrotropes is related to the MCH (minimum hydrotropic concentration) at which hydrotropes start to aggregate. In this work, a series of aromatics compounds that showed hydrotropic effects is used: sodium xylenesulfonate, sodium salicylate, sodium p-toluenesulfonate, sodium benzoate and sodium styrenesulfonate. Different techniques were used to evaluate the MHC, like as: conductivity, surface tension, light scattering, viscosity and fluorescence. The fluorescence spectroscopy was used to determine the MHC by external and internal probe; the moiety phenyl of compounds ring served as the internal fluorescence probe. Intensities of the monomer and excimer contributions (Iaggr/Imonomol) were determined and the pyrene was used as external probe measuring the ratio of intensities I1/I3. It is shown that MHC values determined by different methods agree well. The method based on the aggregate to monomol emission ratio showed advantages when compared to the other method, because it doesn\'t require the use of probes or other additives, which might disrupt the aggregation process.

L'indonésie appartient aux pays en voie de développement du sud-est asiatique. Son développement passe par la valorisation de ses richesses naturelles et plus particulièrement la richesse botanique. L'étude proposée, expose une stratégie de développement industriel des huiles essentielles indonésiennes à 5 ans. Ce travail repose sur 2 réflexions : 1) la réflexion de type marketing qui s'articule autour de la méthode Précom (pré-commercialisation) qui répondra aux questions suivantes : que vendre ?, A qui ?, comment ? ; 2) La réflexion de type prospective s'articule autour de la méthode intégrée de prospective, outil combinant à la fois la méthode Mic-Mac et la méthode Delphi-Régnier. La méthode Mic-Mac permettra de balayer les intéractions entre un grand nombre de variables du système étudié et d'en retenir les 10 variables essentielles avec des degrés de motricité et de dépendance. Ce premier résultat permettra de formaliser la première série d'affirmations (12 items) selon la méthode Delphi-Régnier. L'intégration de ces outils permettra de dégager une stratégie de développement des huiles essentielles indonésiennes à 5 ans qui aura pour objectif : d'apporter la plus grande valeur ajoutée aux produits existants, de concevoir et de fabriquer des produits nouveaux

In order to provide hassle-free connection options many wireless local area network (WLAN) providers choose to have their networks completely open. In other words there is no password required in order to connect. Such open configurations do not provide any security features on the wireless medium, but are often implemented with other solutions as captive portals. A captive portal forces a Hypertext Transfer Protocol (HTTP) client to see a certain webpage, usually for authentication purposes. All other packets are blocked. Once authenticated, the client's medium access control (MAC) address is whitelisted and he will have access to the Internet.The MAC spoofing attack is easy to perform in open networks, see Appendix A. This attack can have severe consequences as the attacker masquerades as a legitimate client, potentially getting the victim caught for crime done by the attacker. The preferred way to handle these attacks has been through detection, as it can be done on the server side without complicating anything for the user. Effective and reliable detection techniques for plain and QoS enabled 802.11 networks exists [1,5]. However, no good solution exists to detect attacks when the legitimate client is no longer connected. The two main scenarios are the session hijacking attack, where the attacker forces the victim offline, and the wait-for-availability attack where the attacker waits until the legitimate client leaves the network.An algorithm based on MAC layer fingerprinting was developed to detect the class of attacks where attacker and victim are not connected simultaneously. A fingerprint is based on the behavior of a station (STA), and each STA's behavior varies due to implementation differences of the 802.11 protocol. Experiments in a real network was performed with 11 different STAs in order to determine the fingerprints. The results show that on average 2.82 of the 8 fingerprinting properties were different when comparing two fingerprints.The fingerprinting algorithm developed is capable of passively creating a fingerprint of wireless STAs without specialized equipment in realistic network conditions. Fingerprints from different STAs are unique with high probability, even when there are little data available. In addition, the technique used is accurate, fast, and requires no pre-computed databases. The algorithm used in combination with the IDS developed by Idland [1] is now able to detect all of the five different MAC spoofing attacks described in Section 2.6.2.

Extrapolation methods for the solution of partial differential equations are commonly based on the existence of error expansions for the approximate solution. Implicit extrapolation, in the contrast, is based on applying extrapolation indirectly, by using it on quantities like the residual. In the context of multigrid methods, a special technique of this type is known as \034 -extrapolation. For finite element systems this algorithm can be shown to be equivalent to higher order finite elements. The analysis is local and does not use global expansions, so that the implicit extrapolation technique may be used on unstructured meshes and in cases where the solution fails to be globally smooth. Furthermore, the natural multilevel structure can be used to construct efficient multigrid and multilevel preconditioning techniques. The effectivity of the method is demonstrated for heat conduction problems and problems from elasticity theory.

The two-dimensional interface crack problem is investigated for anisotropic bodies in the Comninou formulation. It is established that, as in the isotropic case, properly incorporating contact zones at the crack tips avoids contradictions connected with the oscillating asymptotic behaviour of physical and mechanical characteristics leading to the overlapping of material. Applying the special integral representation formulae for the displacement field the problem in question is reduced to the scalar singular integral equation with the index equal to -1. The analysis of this equation is given. The comparison with the results of previous authors shows that the integral equations corresponding to the interface crack problems in the anisotropic and isotropic cases are actually the same from the point of view of the theoretical and numerical analysis.

Diplomová práce je zaměřena na optimální modelování nýtového spoje pro tři různé konfigurace pomocí metody konečných prvků v programu MSC. Nastran/Patran. Na základě prezentovaných výsledků je možné virtuálně simulovat chování nýtových spojů při zatížení, za účelem správného návrhu před provedením statických pevnostních zkoušek. Použitím těchto MKP simulací v procesu certifikace výrobku lze významně redukovat časovou i finanční náročnost pevnostních zkoušek. Při lepším porozumění chování konstrukce lze také lépe predikovat reálnou únosnost nýtových spojů.

The MNC literature treats the (parent) HQ as entirely benevolent with respect to their perceived and actual intentions when they intervene at lower levels of the MNC. However, HQ may intervene in subsidiaries in ways that demotivate subsidiary employees and managers (and therefore harm value-creation). This may happen even if such intervention is benevolent in its intentions. We argue that the movement away from more traditional hierarchical forms of the MNC and towards network MNCs placed in more dynamic environments gives rise to more occasions for potentially harmful intervention by HQ. Network MNCs should therefore be particularly careful to anticipate and take precautions against "intervention hazards". Following earlier research, we point to the role of normative integration and procedural justice, but argue that they also serve to control harmful HQ intervention (and not just subsidiary opportunism). (authors' abstract)

The maternal decidua and the fetally-derived placenta are specialised tissues which have been developed to support mammalian reproduction. Unusual features of the decidua include a leukocyte population dominated by 70% CD56 ^bright NK cells. Invasive placental trophoblast cells penetrate the decidua and express a unique repertoire of Major Histocompatibility Complex (MHC) molecules, which are likely to be significant in maternal immune recognition. Human trophoblast cells do not express the classical HLA-A and HLA-B molecules that are ligands for T cells, but do express HLA-C molecules which are the dominant ligand for NK cells, as well as the non-classical HLA-E and HLA-G molecules. HLA-G is particularly interesting as it is expressed by no other tissues and has no known function. I first investigated expression of the MHC-related ULBP and MIC molecules at the human implantation site, but found no evidence for expression of their protein. I then characterised the conformation of HLA-C and HLA-G molecules at the surface of normal human trophoblast cells isolated from the first trimester of pregnancy at the time of placentation. The majority of HLA-C molecules on trophoblast cells were present in a conventional, b₂m-dissociated open conformers were detected at the cell surface. This suggests that trophoblast HLA-C molecules will provide efficient ligands for KIR receptors on maternal NK cells. In contrast, a significant proportion of HLA-G molecules were found to exist in a disulphide-linked homodimeric complex. This complex was a homodimer of two conventional b₂m-dissociated HLA-1 molecules, which is a conformation unique to HLA-G. Dimeric HLA-G complexes on trophoblast showed substantially higher affinity for the LILRB1 receptor which was expressed by all decidual antigen-presenting cells. This may represent a trophoblast-specific signal to the local maternal uterine immune system.

Syftet med studien har varit att undersöka hur riskfrågor hanteras inom MKB i samband med detaljplaneprocessen och väglagen med dess process samt undersöka om riskkriterier finns. Med riskfrågor menas risker som rör människor och miljö i samband med MKB för projekt. Genom kvalitativa intervjuer, djupintervjuer undersöks om det existerar några riktlinjer för hanteringen av riskfrågor inom MKB hos olika myndigheter samt om det finns riskkriterier som fastställer nivån för acceptabel risk. En bakgrund ges för MKB, risk och risk i samband med MKB. Grundläggande begrepp för MKB redovisas och en kort bakgrund till utvecklingen av MKB ges. Begreppen risk och riskanalys förklaras samt människors riskperception och vad riskkriterier innebär. En introduktion till MKB och riskhantering i samband med detaljplaneprocessen och vägplaneringsprocessen redovisas. Det finns inga riktlinjer för hur risk hanteras i samband med MKB i varken detaljplaneprocessen eller vägplaneringsprocessen. De intervjuade myndigheterna har inga lagstadgade riktlinjer att följa. Avsaknaden av riktlinjer leder till att det är handläggarens erfarenhet som avgör vad som anses viktigt och vilken omfattning som krävs. Vidare visar studien att det inte finns några riskkriterier i Sverige som sätter nivån för acceptabel risk. Avsaknaden av riskkriterier leder till att den beslutande instansen avgör vad som är en tolerabel risk i varje enskilt fall.

Korpusdokumentation wird in dieser Arbeit als eine Voraussetzung für die Wiederverwendung von Korpora und als ein Bestandteil des Forschungsdatenmanagements verstanden, welches unter anderem die Veröffentlichung und Archivierung von Korpora umfasst. Verschiedene Forschungsdaten stellen ganz unterschiedliche Anforderungen an die Dokumentation und können auch unterschiedlich wiederverwendet werden. Ein geeignetes Anwendungsbeispiel stellen historische Textkorpora dar, da sie in vielen Fächern als empirische Grundlage für die Forschung genutzt werden können. Sie zeichnen sich im Weiteren durch vielfältige Unterschiede in ihrer Aufbereitung und durch ein komplexes Verhältnis zu der historischen Vorlage aus. Die Ergebnisse von Transkription und Normalisierung müssen als eigenständige Repräsentationen und Interpretationen im Vergleich zur Vorlage verstanden werden. Was müssen Forscherinnen und Forscher über ihr Korpus mit Hilfe von Metadaten dokumentieren, um dessen Erschließung und Wiederverwendung für andere Forscherinnen und Forscher zu ermöglichen? Welche Funktionen übernehmen dabei die Metadaten? Wie können Metadaten modelliert werden, um auf alle Arten von historischen Korpora angewendet werden zu können? Die Arbeit und ihre Fragestellung sind fest in einem interdisziplinären Kontext verortet. Für die Beantwortung der Forschungsfragen wurden Erkenntnisse und Methoden aus den Fachbereichen der Korpuslinguistik, der historischen Linguistik, der Informationswissenschaft sowie der Informatik theoretisch und empirisch betrachtet und für die Entwicklung eines Metamodells für Korpusmetadaten fruchtbar gemacht. Das im Rahmen dieser Arbeit in UML entwickelte Metamodell für Korpusmetadaten modelliert Metadaten von historischen textbasierten Korpora aus einer technisch-abstrakten, produktorientierten und überfachlichen Perspektive und ist in einer TEI-Spezifikation mit Hilfe der TEI-eigenen Modellierungssprache ODD realisiert.
Corpus documentation is a requirement for enabling corpus reuse scenarios and is a part of research data management which covers, among others, data publication and archiving. Different types of research data make differing demands on corpus documentation, and may be reused in various ways. Historical corpora represent an interesting and challenging use case because they are the foundation for empirical studies in many disciplines and show a great variety of reuse possibilities, of data creation, and of data annotation. Furthermore, the relation between the historical corpus and the historical original is complex. The transcription and normalisation of historical texts must be understood as independent representations and interpretations in their own right. Which kind of metadata information, then, must be included in a corpus documentation in order to enable intellectual access and reuse scenarios? What kind of role do metadata play? How can metadata be designed to be applicable to all types of historical corpora? These research questions can only be addressed with help of an interdisciplinary approach, considering findings and methods of corpus linguistics, historical linguistics, information science and computer science. The metamodel developed in this thesis models metadata of historical text-based corpora from a technical, abstract, and interdisciplinary point of view with help of UML. It is realised as a TEI-specification using the modelling language ODD.

Das Immunsystems muss gesunde Zellen von infizierten und Krebszellen unterscheiden können, um letztere selektiv zu bekämpfen. Dies ist die Aufgabe der CTL-Zellen, die dazu auf der Zelloberfläche präsentierte Peptide die aus intrazellulären Proteinen der jeweiligen Zelle stammen untersuchen. Diese präsentierten Peptide (Epitope) werden durch den MHC-I Antigenpräsentationsweg hergestellt. Das Ziel dieser Arbeit ist es Methoden zu entwickeln die Epitope aus der großen Zahl prinzipiell in Proteinen enthaltener Peptide heraussuchen können. Dazu wird die Selektivität dreier wichtiger Komponenten des Präsentationsweges untersucht: Die Herstellung der Peptide durch das Proteasom, der Transport in das ER durch TAP, und das Binden von Peptiden an leere MHC-I Moleküle. Zur sequenzbasierten Vorhersage der Bindung von Peptiden an MHC-I Moleküle wurde ein neuer Algorithmus entwickelt. Dieser kombiniert eine Matrix, welche die individuellen Beiträge einzelner Reste zur Bindung beschreibt, mit Paarkoeffizienten, die Wechselwirkungen zwischen verschiedenen Positionen im Peptid beschreiben. Dieser Ansatz macht bessere Vorhersagen als bisher publizierte Methoden, und quantifiziert erstmals den Einfluss von Wechselwirkungen innerhalb eines Peptids auf die Bindung. Die Verteilung der Werte der Paarkoeffizienten zeigt, dass sich Wechselwirkungen nicht auf benachbarte Aminosäuren beschränken. Im Vergleich zu den Matrixeinträgen sind die Werte der Paarkoeffizienten klein, was erklärt warum Vorhersagen die Wechselwirkungen komplett vernachlässigen trotzdem gut sein können. Erstmals wurde ein Algorithmus zur Vorhersage der TAP-Transportseffizienz von Peptiden beliebiger Länge entwickelt. Das ist deshalb wichtig, da viele MHC-I Epitope als N-terminal verlängerte Prekursoren in das ER transportiert werden. Für die Vorhersage der Transportfähigkeit eines potentiellen Epitopes wird deshalb über die Transporteffiziens des Epitopes selbst und seiner Prekursoren gemittelt. Mit Hilfe dieser Definition von Transportfähigkeit wird gezeigt, dass TAP einen starken selektiven Einfluss auf die Auswahl von MHC-I Epitopen hat. Indem man Peptide die als 'nicht-transportierbar' vorhergesagt werden als mögliche Epitope ausschließt, kann man die ohnehin schon hohe Qualität von MHC-I Bindungsvorhersagen weiter steigern. So eine zweistufige Vorhersage scheitert, wenn man statt des TAP Transports die Vorhersage der Generierbarkeit eines Epitopes durch das Proteasom als Filter verwenden möchte. Dieses schlechte Abschneiden der proteasomalen Schnittvorhersagen wird auf eine mangelhafte experimentelle Datenbasis zurückgeführt, da proteasomale Schnittraten schwieriger zu messen und interpretieren sind als die Affinitätsdaten für TAP und MHC-I. Um die experimentelle Datenbasis in Zukunft verbessern zu können, wurde ein neues experimentelles Protokoll entwickelt und an einer Reihe von Experimenten getestet. Dabei werden zwei Probleme behandelt: (1) Durch die Verwendung von Massenbilanzen werden MS-Signale in quantifizierte Peptidmengen umgerechnet. (2) Durch das erste kinetische Modell des Proteasomes das die Entstehung und den Abbau von Peptiden während eines Verdaus zufrieden stellend beschreiben kann, können aus den Verdaudaten Schnittraten bestimmt werden.
A major task of the immune system is to identify cells that have been infected by a virus or that have mutated, and discriminate them from healthy cells. This duty is assigned to cytotoxic T-lymphocytes (CTL), which scan epitopes presented to them on cell surfaces derived from intracellular proteins through the MHC-I antigen processing pathway. The goal of this work is to provide computational methods that allow to predict which epitopes get presented from the large pool of peptide candidates contained in intracellular proteins. This is achieved by examining the selective influence of three major steps in the pathway: peptide generation by the proteasome, peptide transport into the ER by TAP, and binding of peptides to MHC-I molecules. For peptide binding to MHC-I, a new algorithm is developed that combines a matrix-based method describing the contribution of individual residues to binding with pair coefficients describing pair-wise interactions between positions in a peptide. This approach outperforms several previously published prediction methods, and for the first time quantifies the impact of interactions in a peptide. The distribution of the pair coefficient values shows that interactions are not limited to amino acids in direct contact, but can also play a role over longer distances. Compared to the matrix entries, the pair-coefficients are rather small, explaining why methods completely ignoring interactions can nevertheless make good predictions. Next, a novel algorithm is developed to predict the TAP affinities of peptides of any length. Longer peptides are important because several MHC-I epitopes are generated by N-terminal trimming of precursor peptides transported into the ER by TAP. As the true in vivo precursors of an epitope are not known, a generalized TAP score is established which averages across the scores of all precursors up to a certain length. The ability of this TAP score to discriminate between epitopes and random peptides shows that the influence of TAP is a consistent, strong pressure on the selection of MHC-I epitopes. Using predicted TAP transport efficiencies as a filter prior to the prediction of MHC-I binding affinities, it is possible to further improve the already very high classification accuracy achieved using MHC-I affinity predictions alone. Such a 2-step prediction protocol failed when predictions of C-terminal proteasomal cleavages were combined with MHC-I affinity predictions. This disappointing result is thought to be caused by the lack of a sufficiently large set of quantitative and consistent experimental data on proteasomal cleavage rates, which are more difficult to measure and interpret than the affinity assays used to characterize peptide binding to TAP and MHC-I. Therefore, a new protocol for the evaluation of proteasomal digests is developed, which is applied to a series of experiments. This novel protocol addresses two problems: (1) Using mass-balance equations, a method is developed to quantify peptide amounts from MS-signals. (2) By introducing the first kinetic model of the 20S proteasome capable of providing a satisfactory quantitative description of the whole time course of product formation, cleavage probabilities can be extracted reliably from proteasomal in vitro digests.

Nesta tese de doutorado estudamos polinômios multivariados. Começamos fazendo uma revisão bibliográfica sobre o teorema da irredutibilidade de Hilbert. Abordamos com detalhes as demonstrações da versão clássica feita pelo próprio Hilbert e das versões efetivas feitas por Erich Kaltofen e Shuhong Gao. Desenvolvemos um novo algoritmo para fatoração de polinômios multivariados inteiros usando logaritmo discreto. Nosso método é baseado em novos tipos de reduções de polinômios multivariados para polinômios bivariados, as quais têm como principal característica manter a esparsidade do polinômio. Nosso método mostrou-se eficiente quando usado para fatorar polinômios multivariados que possuem apenas fatores esparsos e quando usado para extrair fatores esparsos de polinômios multivariados que têm fatores esparsos e densos. Terminamos essa tese trabalhando com o máximo divisor comum (mdc) de polinômios. Estudamos critérios geométricos de politopos para determinar coprimalidade entre polinômios multivariados. Desenvolvemos um novo algoritmo que trabalha em tempo polinomial (sobre o número de monômios) para detectar coprimalidade entre polinômios multivariados usando seus politopos de Newton associados. Esse método geométrico tem a vantagem de determinar a coprimalidade entre famílias de polinômios, pois podemos mudar arbitrariamente os coeficientes dos polinômios desde que certos coeficientes permaneçam não nulos. Além disso, os polinômios permanecerão coprimos sobre qualquer corpo. Terminamos mostrando como construir o mdc entre dois polinômios bivariados usando seus polígonos de Newton associados.
In this dissertation we study multivariate polynomials. We begin with a bibliographical review on the Hilbert irreducibility theorem. We cover in detail the demonstrations of the classic version due to Hilbert himself and effective versions due to Erich Kaltofen and Shuhong Gao. We developed a new algorithm for factoring multivariate integral polynomials using discrete logarithm. Our method is based on new types of reductions, from multivariate polynomias to bivariate polynomials, whose main feature is to maintain the sparsity of the polynomial. Our method has proved to be eficient when used for factoring multivariate polynomials that have only sparse factors and when used to extract sparse factors of multivariate polynomials that have sparse and dense factors. We finish this dissertation studying the greatest common divisor (gcd) of polynomials. We study geometric criteria of polytopes to determine coprimality between multivariate polynomials. We developed a new algorithm that works in polynomial time (on the number of monomials) to detect coprimality between multivariate polynomials using their associated Newton polytopes. This geometric method has the advantage of determining the coprimality between families of polynomials, since we can arbitrarily change the polynomial coeficients as long as some coeficients remain nonzero. Moreover, the coprime polynomials shall remain coprime on anyfield. We ended up showing how to build the gcd between two bivariate polynomials using their associated Newton polygons.

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção.
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O desenvolvimento das chamadas novas tecnologias tem promovido mudanças fundamentais na estrutura e nos processos de trabalho. A adoção mais intensa de sistemas automatizados e modernos equipamentos tem levado as áreas de manutenção a uma posição estratégica, em face da importância da disponibilidade operacional para o resultado global das empresas. O objetivo geral deste trabalho é avaliar o impacto da aplicação da Manutenção Centrada em Confiabilidade (MCC), um método que enfatiza a análise das funções dos equipamentos e conseqüências das falhas, na sistemática de manutenção da Central Hidrelétrica de Itaipu, particularmente no Sistema de Operação e

L'histoire des idées fonctionne comme un crible : certains auteurs sont recueillis avec ferveur, d'autres non. A ce sujet, Bateson parle d'une véritable écologie de l'esprit. Herbert Marshall Mac Luhan (1911-1980) a connu un sort paradoxal : annonçant la modernité, ce qu'il nomme la galaxie Marcani. Il a été rejeté par les philosophes français de 1968. Or, ses idées seront reprises par les penseurs de la postmodernité, en guise de reconnaissance posthume. Nous avons voulu savoir les raisons de ce revirement. Pourquoi un homme aussi célèbre a-t-il été ignore par la "pensée 68" ? Pourquoi a-t-il été représenté comme un prophète, alors que l'évolution technologique a corroboré ses intuitions ? Malgré ses attaques contre le livre, plus exactement contre la rationalité littéraire, Mac Luhan est un humaniste prônant, dans une réalité quotidienne néobaroque, une forme de fidéisme : s’il n'est plus possible de penser le monde, car l'illusion règne, la force du lien entre les hommes doit donner sens à la vie
History of ideas works like a riddle : some authors are selected, some not. Thinking of this, Bateson talks about a real ecology of mind. Herbert Marshall Mac Luhan (1911-1980) was a living paradox : introducing modernity with his concept of marconi galaxy, he was ignored by french thinkers of the late sixties. Or, the same ideas will be taken again, without refering to him, by post modernity philosophers. What are the reasons of such a contempt ? Why an essayist as famous as Mac Luhan was not accepted by the french intelligentzia of 1968 ? Was he a prophet, when he was annoucing the future of technology ? Not with standing his attacks against rationality, mac luhan was an humanist, maybe a fideist : if it's difficult to build a clear vision of the world, because of the stength of illusion, relationship between men must give a meaning to modern life