Monodromy analysis of the computational power of the Ising topological quantum computer

We show that all quantum gates which could be implemented by braiding of Ising anyons in the Ising topological quantum computer preserve the n-qubit Pauli group. Analyzing the structure of the Pauli group's centralizer, also known as the Clifford group, for n\geq 3 qubits, we prove that the image of the braid group is a non-trivial subgroup of the Clifford group and therefore not all Clifford gates could be implemented by braiding. We show explicitly the Clifford gates which cannot be realized by braiding estimating in this way the ultimate computational power of the Ising topological quantum computer.Comment: 10 pages, 2 figures and 1 table; v2: one more reference added and some typos corrected; Talk given at the VIII International Workshop "Lie Theory and its Applications in Physics", 15-21 June 2009, Varna, Bulgari

Asymptotic behavior of decoherent and interacting quantum walks

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The Multi-Agent Programming Contest: A r\'esum\'e

The Multi-Agent Programming Contest, MAPC, is an annual event organized since 2005 out of Clausthal University of Technology. Its aim is to investigate the potential of using decentralized, autonomously acting intelligent agents, by providing a complex scenario to be solved in a competitive environment. For this we need suitable benchmarks where agent-based systems can shine. We present previous editions of the contest and also its current scenario and results from its use in the 2019 MAPC with a special focus on its suitability. We conclude with lessons learned over the years.Comment: Submitted to the proceedings of the Multi-Agent Programming Contest 2019, to appear in Springer Lect. Notes Computer Challenges Series https://www.springer.com/series/1652

Quantum Walks with Non-Orthogonal Position States

Quantum walks have by now been realized in a large variety of different physical settings. In some of these, particularly with trapped ions, the walk is implemented in phase space, where the corresponding position states are not orthogonal. We develop a general description of such a quantum walk and show how to map it into a standard one with orthogonal states, thereby making available all the tools developed for the latter. This enables a variety of experiments, which can be implemented with smaller step sizes and more steps. Tuning the non-orthogonality allows for an easy preparation of extended states such as momentum eigenstates, which travel at a well-defined speed with low dispersion. We introduce a method to adjust their velocity by momentum shifts, which allows to investigate intriguing effects such as the analog of Bloch oscillations.Comment: 5 pages, 4 figure

Impact of the epithelial hypoxia-inducible factor 2 alpha/fetal liver kinase-1 system on murine lung development

In the present study, we hypothesized that the HIF 2 alpha/flk-1 system has a unique role in the pulmonary epithelial system, with further impact on lung development. This hypothesis was based on data by Compernolle et al. showing a severe respiratory distress syndrome upon global HIF 2 alpha deletion which could be overcome by the application of VEGF (Compernolle et al., 2002). However, key functions of the HIF 2 alpha/flk-1 system have been demonstrated to be restricted to the vascular system, to regulate physiological and pathological blood vessel formation. In contrast, reports by Brown et al. and Raoul et al. suggest a direct influence of the flk-1/VEGF system on pulmonary epithelial cell function (Brown et al., 2001; Raoul et al., 2004). Since flk-1 has been shown to be regulated by HIF 2 alpha (Elvert et al., 2003) it represents the functional target molecule of the HIF 2 alpha/flk-1 system. Accordingly, we characterized flk-1 expression from ED12.5 at daily intervals throughout lung development until postnatal stages. We found flk-1 expression, as previously described, in the early primitive vascular network. At the end of the pseudoglandular stage, at ED16.5 we found widespread epithelial expression of flk-1 which persisted until postnatal stages. Furthermore, we analyzed flk-1 expression and functional integrity in isolated adult (Ahlbrecht et al., 2008). To test our hypothesis of a direct functional impact of the HIF 2 alpha/flk-1 system on the pulmonary epithelial system, we analyzed isolated AEC for HIF 2 alpha expression, and found strong expression of HIF 2 alpha at the protein level. Thus, we demonstrated that the HIF 2 alpha/flk-1 system is not restricted to the endothelial system, and is present in the pulmonary alveolar epithelial system. To analyze the functional impact of this newly characterized pulmonary epithelial system, we generated an inducible in vivo pulmonary epithelial HIF 2 alpha deletion combining the SPCrtTA and Cre-loxP system. We succeeded in generating the epithelial HIF 2 alpha deletion which could be demonstrated at the protein level. But, in contrast to our hypothesis that the epithelial HIF 2 alpha/flk-1 system might have functional impact on lung development, epithelial HIF 2 alpha deletion did not lead to a disorder or phenotype. Even though flk-1 was strongly downregulated, no changes were observed regarding lung structure or AEC morphology and SPC expression respectively. This was unexpected. Thus we postulate that the epithelial HIF 2 alpha system works within a complex network. Upon HIF 2 alpha deletion, a compensatory system takes over the HIF 2 alpha-related functions to rescue the deletion to protect the process of lung development. This is highly speculative and further investigations are needed to characterize the different factors involved which were not addressed in the present study. Taken together our study demonstrates: Characterization of flk-1 expression at daily intervals throughout lung development with epithelial expression of flk-1 rising from ED16.5 and persisting at postnatal stages (Ahlbrecht et al., 2008). Furthermore HIF 2 alpha and flk-1 expression could be demonstrated in isolated AEC. Thus, we were able to demonstrate the existence of the epithelial HIF 2 alpha/flk-1 system. Analysis of the direct epithelial function of the newly characterized pulmonary epithelial system could be addressed by successful generation of an pulmonary epithelial-restricted HIF 2 alpha in vivo deletion using the SPCrtTA-tetO-Cre system. Surprisingly, characterization of the phenotype of pulmonary epithelial HIF 2 alpha knock-out mice did not show any disorders or phenotype, or changes in lung structure and epithelial cell development. These data may be basis for future studies elucidating the network of cooperating factors regulating pulmonary epithelial development.In der vorliegenden Arbeit wird die Hypothese untersucht, dass das HIF 2 alpha/flk-1 System eine eigenständige funktionelle Rolle in dem pulmonalen epithelialen System spielt und darüber Einfluss auf die Lungenentwicklung nimmt. Diese Hypothese basiert auf Untersuchungen von Compernolle et al. die ein akutes Lungenversagen als Folge einer globalen HIF 2 alpha Deletion beschreiben, welches durch Applikation von VEGF überwunden werden konnte (Compernolle et al., 2002). Bisher wurde die Regulation der physiologischen und pathologischen Blutgefäßentwicklung als die zentrale Funktion des HIF 2 alpha/flk-1 Systems beschrieben. Die Wirkungsweise schien somit auf das vasculäre System begrenzt zu sein. Demgegenüber deuten jedoch Daten von Brown et al. und Raoul et al. darauf hin, dass das flk-1/VEGF System auch direkten Einfluss auf die Funktion des pulmonalen epithelialen Systems zu nehmen scheint (Brown et al., 2001; Raoul et al., 2004). Flk-1 wird durch HIF 2 alpha reguliert (Elvert et al., 2003) und stellt somit das funktionelle Zielmolekül des HIF 2 alpha/flk-1 Systems dar. Diesbezüglich charakterisierten wir in dieser Arbeit zunächst die flk-1 Expression während der Lungenentwicklung täglich von ED12.5 bis hin zu postnatalen Stadien. Als Ergebnis zeigte sich in den frühen Stadien die flk-1 Expression wie bereits beschrieben in dem frühen primitiven vasculären Netzwerk. Am Ende der pseudoglandulären Phase zeigte sich eine großflächige epitheliale flk-1 Expression, die bis in die postnatalen Stadien zu finden war. Des Weiteren konnten wir in murinen isolierten alveolären Epithelzellen die flk-1 Expression und Aktivierung nachweisen (Ahlbrecht et al., 2008). Darüber hinaus zeigte sich eine starke Expression von HIF 2 alpha in diesen Zellen. Um die Funktion des nun neu charakterisierten pulmonalen epithelialen Systems zu analysieren, generierten wir eine in vivo pulmonal epithelzellspezifisches HIF 2 alpha Deletion mittels SPCrtTA- und tetO-Cre System in einem dreifach transgenen Mausmodel. Die erfolgreiche Deletion zeigte sich auf Proteinebene. Gegensätzlich zu der zu Grunde liegenden Hypothese einer spezifischen Funktion des epithelialen HIF 2 alpha/flk-1 Systems, zeigte sich jedoch kein pathologischer Phenotyp. Es zeigte sich eine stark reduzierte epitheliale flk-1 Expression, die sich jedoch nicht auf die Lungenstruktur, Epithelzellmorphologie oder SPC Expression auswirkte. Auf Grund dieser unerwarteten Ergebnisse postulieren wir, dass das HIF 2 alpha/flk-1 System in ein komplexes Netzwerk von Faktoren integriert ist, welches bei Deletion eines Faktors die Funktion übernehmen kann, um eine ungestörte Entwicklung zu ermöglichen. Das ist eine spekulative Vermutung, zu deren Klärung weitere Studien notwendig sind, um die unbekannten Faktoren des Netzwerkes zu untersuchen, die in der vorliegenden Arbeit nicht untersucht wurden. Zusammenfassend konnte die vorliegende Arbeit folgendes zeigen: Charakterisierung der flk-1 Expression während der Lungenentwicklung in täglichen Intervallen. Es zeigte sich eine epitheliale flk-1 Expression von ED16.5 beginnend und persistierend bis zu postnatalen Stadien (Ahlbrecht et al., 2008). Darüber hinaus konnte die epitheliale HIF 2 alpha Expression in isolierten alveolaren Epithelzellen (AEC) gezeigt werden, und so die Existenz eines epithelialen HIF 2 alpha/flk-1 Systems demonstriert werden. Als in vivo Model zur funktionellen Analyse des neu charakterisierten pulmonal epithelialen Systems konnte eine pulmonal epithelzellspezifische HIF 2 alpha Deletion mittels SPCrtTA-tetO-Cre Systems in einem dreifach transgenen Ansatz erzielt werden. Entgegen der Hypothese einer speziellen Funktion des epithelialen HIF 2 alpha/flk-1 Systems zeigte sich kein pathologischer Phenotyp unter der epithelspezifischen HIF 2 alpha Deletion bezüglich Lungenstruktur und Epithelzellentwicklung. Diese Daten können eine Basis für weitere Studien darstellen, die das Netzwerk der involvierten Faktoren der Lungenentwicklung und speziell der pulmonalen Epithelzellentwicklung weiter aufklären

Impact of Mobility on Information Systems and Information System Design

The subject of this thesis is to analyse the impact of mobile hardware and software on information systems, to survey existing approaches for specifying mobile systems of computer science in general, and to provide suitable means for the formal design of information systems comprising such mobile units in particular. We consider a mobile unit to denote a mobile hardware or software entity, and a mobile system as a system comprising or being accessed by such mobile components. The various forms of mobile units occurring in computer science are explained and a taxonomy for them is developed, followed by a detailed discussion of their effects on computer and information systems. Several approaches for specifying mobile systems are presented and classified, with a particular emphasis on formal methods. As it turns out, these approaches do not allow to describe the set-up and release of communication links or to distinguish between the ever-mobile units of a compound system and those which provide the fixed subsystem as the context for the mobile entities, which are both important aspects to consider when developing information systems with mobile components. Therefore, corresponding constructs are then presented as an extension to the specification language Troll and its theoretical foundations, i.e. extended data signatures and the Module Distributed Temporal Logic Mdtl, both being interpreted over event structures. Finally, the application of the constructs is illustrated with the development of a system for accessing web services from mobile phones, which complements the ongoing example of information retrieval via mobile agents used to explain the constructs and concepts.Thema dieser Arbeit ist die Analyse der Auswirkungen von mobiler Hard- und Software auf Informationssysteme, die Untersuchung vorhandener Ansätze zur Spezifikation mobiler Systeme in der Informatik allgemein und für den formalen Entwurf von Informationssystemen mit mobilen Einheiten insbesondere. "Mobile Einheit" wird dabei als Oberbegriff für mobile Hardware- und Softwarekomponenten verwendet, und ein "mobiles System" ist ein System, das solche mobilen Komponenten beinhaltet oder auf das durch diese zugegriffen wird. Wir beschreiben die verschiedenen Formen, in denen mobile Einheiten in der Informatik auftreten, und entwickeln eine entsprechende Taxonomie, bevor wir deren Auswirkungen auf Computer- und Informationssysteme ausführlich diskutieren. Verschiedene Ansätze zur Spezifikation mobiler Systeme werden vorgestellt und eingeordnet, wobei das Augenmerk speziell auf formalen Methoden liegt. Es stellt sich heraus, dass es keiner dieser Ansätze ermöglicht, den Auf- und Abbau von Kommunikationsverbindungen zu beschreiben und zwischen den stets mobilen Einheiten und denjenigen zu unterscheiden, die das feste Teilsystem als Kontext für sie bilden. Beides sind aber wesentliche Aspekte, die in der Entwicklung von Informationssystemen mit mobilen Bestandteilen zu berücksichtigen sind. Daher stellen wir dann entsprechende Sprachkonstrukte als Erweiterung der Spezifikationssprache Troll inklusive der formalen Grundlagen vor. Diese Grundlagen beruhen auf erweiterten Datensignaturen und einer modularen verteilten temporalen Logik Mdtl, die beide über Ereignisstrukturen interpretiert werden. Schließlich wird die Verwendbarkeit der Sprachkonstrukte in der Entwicklung eines Systems zur Nutzung von Web-Diensten von Mobiltelefonen aus illustriert

Model-Based STPA: Enabling Safety Analysis Coverage Assessment with Formalization

Urban Air Mobility introduces safety-related challenges for future avionics systems. The associated need for increased autonomy demands novel functions based on highperformance algorithms. To provide such functionality in future air vehicles of all sizes, the trend is towards centralized and powerful computing platforms. That turns avionics into a complex, integrated, and software-intensive aircraft system. Simultaneously, this increases the need for adapted safety analyses. The System-Theoretic Process Analysis is a promising approach to analyze the safety of software-intensive systems. It enables consideration of interaction and specification issues additional to component failures. However, even when using state-of-the-art analyses such as STPA, claiming the sufficiency of the safety analysis efforts is a challenging tasks for systems with everincreasing complexity. To address this issue, this paper extends the coverage analysis concepts known from the software development to safety analyses. This is achieved with the utilization of failure graphs, i.e., formalized analysis summaries that can be automatically created during the safety analysis. Failure graphs have two advantages: they provide the possibility for visual analysis state indication and can be used to calculate various statistical metrics. Thereby, they allow to improve the knowledge about the depth, breadth, and state of the safety analysis. Both visual and statistical consideration complement each other to enhance the safety analysis coverage assessment for future avionic systems. To show all capabilities, the analysis of a flight assistance system serves as demonstrator

Электрооборудование и электропривод механизма напора экскаватора ЭКГ-15

В работе произведён расчёт и выбор силового оборудования для электропривода механизма напора карьерного экскаватора.Произведен расчет силовой части электропривода. Рассчитаны и построены характеристики электропривода, построены переходные процессы.In operation, calculation and selection of power equipment for electric drive of pressure mechanism of mine excavator was performed. Electric drive power part was calculated. The characteristics of the electric drive have been calculated and built, and transitional processes have been built