2,431 research outputs found

    Balanced Truncation of k-Positive Systems

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    This paper considers balanced truncation of discrete-time Hankel kk-positive systems, characterized by Hankel matrices whose minors up to order k are nonnegative. Our main result shows that if the truncated system has order kk or less, then it is Hankel totally positive (\infty-positive), meaning that it is a sum of first order lags. This result can be understood as a bridge between two known results: the property that the first-order truncation of a positive system is positive (k=1k=1), and the property that balanced truncation preserves state-space symmetry. It provides a broad class of systems where balanced truncation is guaranteed to result in a minimal internally positive system.T We would like to thank the anonymous reviewers for their outstanding support. The research leading to these results was completed while the first author was a postdoctoral research associate at the University of Cambridge. The research has received funding from the European Research Council under the Advanced ERC Grant Agreement Switchlet n.67

    Finite automata with advice tapes

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    We define a model of advised computation by finite automata where the advice is provided on a separate tape. We consider several variants of the model where the advice is deterministic or randomized, the input tape head is allowed real-time, one-way, or two-way access, and the automaton is classical or quantum. We prove several separation results among these variants, demonstrate an infinite hierarchy of language classes recognized by automata with increasing advice lengths, and establish the relationships between this and the previously studied ways of providing advice to finite automata.Comment: Corrected typo

    Improved Pregnancy Outcome in Type 1 Diabetic Women With Microalbuminuria or Diabetic Nephropathy: Effect of intensified antihypertensive therapy?

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    OBJECTIVE—To describe pregnancy outcome in type 1 diabetic women with normoalbuminuria, microalbuminuria, or diabetic nephropathy after implementation of an intensified antihypertensive therapeutic strategy

    Design and rationale of a large, international, prospective cohort study to evaluate the occurrence of malformations and perinatal/neonatal death using insulin detemir in pregnant women with diabetes in comparison with other long-acting insulins

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    BACKGROUND: There are a lack of data regarding the effect of basal insulin analogues on rates of events like congenital malformation and perinatal mortality in diabetic pregnancy. METHODS: The present study is a prospective, non-interventional, multicentre cohort study conducted in seven countries, designed to assess the safety of insulin detemir during pregnancy, and to monitor the health status of resulting infants (exposed in utero) up to 1 year of age. The study population includes women with type 1 or type 2 diabetes, who are pregnant and being treated with insulin. Data will be collected in the context of routine practice. The primary endpoint is the proportion of pregnancies in women treated with insulin detemir, compared with other basal insulin regimens, which do not result in any of the following events: major congenital malformations, perinatal death or neonatal death. A sample size of 3075 pregnancies was calculated to provide an 80% power to detect a difference of 3.5% between groups in the primary endpoint at a 5% level. DISCUSSION: The study will also examine other important maternal endpoints (e.g., incidences of severe hypoglycaemia and pre-eclampsia) and perinatal outcomes such as overweight neonates, as well as infant outcomes at 1 year of age. It has a fixed recruitment period from 2013 to 2018, enrolling all eligible patients, and is expected to inform future prescribing with basal insulins in diabetic pregnancy. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01892319 (date registered: 27.06.2013). ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12884-016-1177-4) contains supplementary material, which is available to authorized users

    Towards Model Checking Executable UML Specifications in mCRL2

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    We describe a translation of a subset of executable UML (xUML) into the process algebraic specification language mCRL2. This subset includes class diagrams with class generalisations, and state machines with signal and change events. The choice of these xUML constructs is dictated by their use in the modelling of railway interlocking systems. The long-term goal is to verify safety properties of interlockings modelled in xUML using the mCRL2 and LTSmin toolsets. Initial verification of an interlocking toy example demonstrates that the safety properties of model instances depend crucially on the run-to-completion assumptions

    Poor pregnancy outcome in women with type 1 diabetes is predicted by elevated HbA1c and spikes of high glucose values in the third trimester

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    OBJECTIVE: To analyse data from a randomised, controlled study of prandial insulin aspart versus human insulin, both with NPH insulin, in pregnant women with type 1 diabetes for potential factors predicting poor pregnancy outcomes. RESEARCH DESIGN/METHOD: Post hoc analysis including 91 subjects randomised prior to pregnancy with known outcome in early pregnancy and 259 subjects randomised prior to pregnancy/during pregnancy of <10 weeks’ gestation with known late-pregnancy outcomes. Poor early-pregnancy outcomes included fetal loss <22 gestational weeks and/or congenital malformation (n = 18). Poor late-pregnancy outcomes included: composite endpoint including pre-eclampsia, preterm delivery and perinatal death (n = 78); preterm delivery (n = 63); and excessive fetal growth (n = 88). RESULTS: 18 patients experienced a malformed/lost fetus in early pregnancy – none preceded by severe hypoglycaemia. Albuminuria in early pregnancy was a significant predictor of poor late-pregnancy outcome (composite endpoint; p = 0.012). In the third trimester, elevated HbA(1c), ≥ 1 plasma glucose (PG) measurement >11 mmol/L (198 mg/dL) and %PG values outside 3.9–7.0 mmol/L (70–126 mg/dL) were significant predictors of poor late-pregnancy outcomes (all p < 0.05). CONCLUSIONS: Elevated HbA(1c), high glucose spikes and out-of-range %PG in the third trimester, and albuminuria in early pregnancy, are associated with poor late-pregnancy outcomes

    Wende oder friedliche Revolution? Ungleiche Deutungen einer historischen Zäsur

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    Auch nach 20 Jahren ist die Debatte über die Ereignisse vom Herbst 1989 noch lebendig. Auch wenn sich inzwischen für den Sturz der SED-Diktatur der Begriff 'Wende' statt 'friedliche Revolution' durchgesetzt hat, lässt sich das Attribut 'friedlich' bei der Beschreibung der Ereignisse kaum vermeiden. Das Ende der DDR ist ein Musterbeispiel für einen neuen Typ demokratischer Revolutionen, die durch die Abwesenheit von Gewalt gekennzeichnet sind. Erstaunlich ist, das der gewaltfreie Charakter dieses revolutionären Herbstes bis jetzt kaum diskutiert worden ist. Er war schließlich keine Selbstverständlichkeit - vielfach schien der Ausbruch von Gewalt kurz bevor zu stehen. Zu den erstaunlichen Erkenntnissen gehört, dass die Demonstranten gleichzeitig strategisch und spontan handelten und so effektiv die Pläne der SED-Führung vereitelten. Die Spontaneität der 'friedlichen Revolution' scheint der Schlüssel zu ihrem Erfolg gewesen zu sein. (ICEÜbers)'Even almost 20 years later, the debate on the nature of the events of the autumn of 1989 is still in full flow. Although rather the term 'Wende' (Fundamental Change) than 'Peaceful Revolution' has pushed through for the fall of the SED dictatorship, it is hardly possible not to use the attribute - 'revolutionary' for the events: the end of the GDR is an example of a new type of 'democratic revolutions' which are characterized by non-violence. It is astonishing that for the time being the non-violent nature of this autumn of revolution has hardly been discussed, particularly in the field of the research on non-violence. After all, it was far from being a matter of course: in many situations a violent escalation seemed to be imminent. It is one of the most astonishing insights that the actors of the demonstration movement acted strategically but nevertheless spontaneously and thus effectively made the plans of the SED leadership come to nothing. After all, it seems as if the spontaneity of the 'Peaceful Revolution' was the key to its success.' (author's abstract)

    Association of Machine Learning–Based Predictions of Medial Knee Contact Force With Cartilage Loss Over 2.5 Years in Knee Osteoarthritis

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    Objective: The relationship between in vivo knee load predictions and longitudinal cartilage changes has not been investigated. We undertook this study to develop an equation to predict the medial tibiofemoral contact force (MCF) peak during walking in persons with instrumented knee implants, and to apply this equation to determine the relationship between the predicted MCF peak and cartilage loss in patients with knee osteoarthritis (OA). Methods: In adults with knee OA (39 women, 8 men; mean ± SD age 61.1 ± 6.8 years), baseline biomechanical gait analyses were performed, and annualized change in medial tibial cartilage volume (mm3 /year) over 2.5 years was determined using magnetic resonance imaging. In a separate sample of patients with force-measuring tibial prostheses (3 women, 6 men; mean ± SD age 70.3 ± 5.2 years), gait data plus in vivo knee loads were used to develop an equation to predict the MCF peak using machine learning. This equation was then applied to the knee OA group, and the relationship between the predicted MCF peak and annualized cartilage volume change was determined. Results: The MCF peak was best predicted using gait speed, the knee adduction moment peak, and the vertical knee reaction force peak (root mean square error 132.88N; R2 = 0.81, P < 0.001). In participants with knee OA, the predicted MCF peak was related to cartilage volume change (R2 = 0.35, β = -0.119, P < 0.001). Conclusion: Machine learning was used to develop a novel equation for predicting the MCF peak from external biomechanical parameters. The predicted MCF peak was positively related to medial tibial cartilage volume loss in patients with knee OA

    Fe1-xNix alloy nanoparticles encapsulated inside carbon nanotubes: Controlled synthesis, structure and magnetic properties

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    In the present work, different synthesis procedures have been demonstrated to fill carbon nanotubes (CNTs) with Fe1-xNix alloy nanoparticles (x = 0.33, 0.5). CNTs act as templates for the encapsulation of magnetic nanoparticles, and provide a protective shield against oxidation as well as prevent nanoparticles agglomeration. By variation of the reaction parameters, the purity of the samples, degree of filling, the composition and size of filling nanoparticles have been tailored and therefore the magnetic properties. The samples were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Bright-field (BF) TEM tomography, X-ray powder diffraction, superconducting quantum interference device (SQUID) and thermogravimetric analysis (TGA). The Fe1-x Nix-filled CNTs show a huge enhancement in the coercive fields compared to the corresponding bulk materials, which make them excellent candidates for several applications such as magnetic storage devices
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