1,632 research outputs found

    LPV model-based robust diagnosis of flight actuator faults

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    A linear parameter-varying (LPV) model-based synthesis, tuning and assessment methodology is developed and applied for the design of a robust fault detection and diagnosis (FDD) system for several types of flight actuator faults such as jamming, runaway, oscillatory failure, or loss of efficiency. The robust fault detection is achieved by using a synthesis approach based on an accurate approximation of the nonlinear actuator-control surface dynamics via an LPV model and an optimal tuning of the free parameters of the FDD system using multi-objective optimization techniques. Real-time signal processing is employed for identification of different fault types. The assessment of the FDD system robustness has been performed using both standard Monte Carlo methods as well as advanced worst-case search based optimization-driven robustness analysis. A supplementary industrial validation performed on the AIRBUS actuator test bench for the monitoring of jamming, confirmed the satisfactory performance of the FDD system in a true industrial setting

    A Versatile Simulation Environment of FTC Architectures for Large Transport Aircraft

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    We present a simulation environment with 3-D stereo visualization facilities destined for an easy setup and versatile assessment of fault detection and diagnosis based fault tolerant control systems. This environment has been primarily developed as a technology demonstrator of advanced reconfigurable flight control systems and is based on a realistic six degree of freedom flexible aircraft model. The aircraft control system architecture includes a flexible fault detection and diagnosis system and a reconfigurable nonlinear dynamic inversion based controller, able to handle different fault situations

    Non-abelian lattice gauge theory with a topological action

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    SU(2) gauge theory is investigated with a lattice action which is insensitive to small perturbations of the lattice gauge fields. Bare perturbation theory can not be defined for such actions at all. We compare non-perturbative continuum results with that obtained by the usual Wilson plaquette action. The compared observables span a wide range of interesting phenomena: zero temperature large volume behavior (topological susceptibility), finite temperature phase transition (critical exponents and critical temperature) and also the small volume regime (discrete β-function or step-scaling function). In the continuum limit perfect agreement is found indicating that universality holds for these topological lattice actions as well

    LEGAL AND ORGANIZATIONAL SITUATION IN AGRICULTURE OF THE VIROVITICA COUNTY AND THE CITY OF OSIJEK IN THE SECOND HALF OF THE 18TH CENTURY

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    The Treaty of Karlowitz signed in 1699 concluded the rule of the Ottoman Empire in most parts of Central and Eastern Europe. Liberation of Osijek in 1687, and consequently of whole Slavonia in 1699 brought a new era of freedom and prosperity to its citizens. At least for a short time, since the Habsburg Monarchy re-established their rule over the country by bringing feudal laws and regulations back into force. Austrian empress and Hungarian-Croatian Queen Maria Theresa united Slavonia with Croatia, and re-established the counties of Virovitica, Požega and Syrmia, meaning that the regional administration of Slavonia was completely relinquished to the civil authorities

    Prognostic relevance of mixed histological subtypes in invasive breast carcinoma: a retrospective analysis

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    Purpose: The prognostic and therapeutic power of special histological subtypes in breast cancer in pure form or in combination with other histological subtypes is still not established, and diagnostic guidelines are cautious regarding prognostic power based on the histological subtype alone. Therapy decisions are guided in most cases independently of the histological subtype and are directed by biomarkers and tumor stage. In this study, we analyzed a comprehensive large retrospective breast cancer cohort with a special focus on histological subtype (other than ductal non-special type or lobular carcinoma) and correlated pure or mixed histological forms with pathological tumor stage and overall disease-free survival. Materials and methods: A total of 827 breast cancer cases with pure or mixed special histological types were retrospectively analyzed. Survival information was available in 645 of 827 cases. Results: A total of 293 cases had pure forms, and 534 cases had mixed histological subtypes. The most common pure special types were mucinous (23.9%), micropapillary (21.2%), high-grade metaplastic (13%), male breast cancer (8.2%), cribriform (6.8%), metastases (6.1%), apocrine and papillary (each 5.46%), NST with medullary and clear cell pattern (up to 3.4%) and high-grade neuroendocrine carcinomas (2.7%). Mixed forms were most frequently encountered in NST carcinomas with micropapillary components (41.8%), followed by mucinous (9.93%) and cribriform (6.74%) mixed patterns. In univariate analysis, no pure form had prognostic relevance compared with any mixed form with the basic pure element. Pooling pure histological subtypes with tumor stage and age in a linear random-effects model, the cribriform subtype had the most favorable prognosis, while male breast cancer showed the poorest outcome (p < 0.001). All other frequent pure forms had intermediate prognostic power (p < 0.001). Conclusion: Our results show that the analyzed special histological breast cancer subtypes (other than ductal and lobular carcinomas) do not carry prognostic information alone, either in pure form or in any combination with other subtypes. Prognostic groups including special subtypes, however, can strongly stratify breast cancer if tumor stage, age and biomarkers are included in the prognostic measurements. Keywords: Breast cancer; Prognosis; Special histological subtypes

    Die SLICOT-Toolboxen für MatlabThe SLICOT Toolboxes for Matlab

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    SLICOT ist eine umfangreiche Softwarebibliothek zur numerischen Behandlung von Fragestellungen aus der System- und Regelungstheorie, die mit dem Ziel entwickelt wurde, hohe Leistungsfähigkeit mit Robustheit, Verlässlichkeit, sowie Benutzerfreundlichkeit zu vereinen. Dies wird mittels einer Kombination von Fortran-Kernroutinen und Matlab- bzw. Scilab-Schnittstellen erreicht. In dieser Übersicht soll der Funktionsumfang der folgenden SLICOT-Toolboxen beschrieben und erläutert werden: (1) Grundaufgaben der System- und Regelungstheorie, (2) Systemidentifizierung, (3) Modell- und Reglerreduktion. Der Einsatz der Toolboxen in der Praxis wird durch verschiedene Beispiele veranschaulich

    Effect of crystalline disorder on magnetic switching in small magnetic cells

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    I present a study of the influence of disorder in thin magnetic films on the switching behavior of small magnetic cells of well defined shape and size. The disorder considered arises from randomly oriented crystalline grains of different shape, size, and crystalline orientation which gives rise to locally fluctuating intrinsic anisotropy directions and strengths. The study comprises a theoretical investigation of a disordered Stoner Wohlfarth model, as well as micromagnetic simulations. I show that the fluctuations in the total anisotropy and therefore in the switching fields are controlled by a single dimensionless parameter. The theoretical findings are well confirmed by micromagnetic simulations of many different samplesComment: 18 pages of LaTex, 5 eps figures. Originally submitted to J. Magn. Mag. Mater. on January 3, 200
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