276 research outputs found

    Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Current and advanced act control system definition study. Volume 2: Appendices

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    The current status of the Active Controls Technology (ACT) for the advanced subsonic transport project is investigated through analysis of the systems technical data. Control systems technologies under examination include computerized reliability analysis, pitch axis fly by wire actuator, flaperon actuation system design trade study, control law synthesis and analysis, flutter mode control and gust load alleviation analysis, and implementation of alternative ACT systems. Extensive analysis of the computer techniques involved in each system is included

    Basement-involved reactivation in foreland fold and thrust belts: the Alpine-Carpathian Junction (Austria)

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    The Late Eocene to Early Miocene Alpine-Carpathian fold-and-thrust belt (FTB) lies in the transition between the Eastern Alps and the Western Carpathians, southeast of the Bohemian crystalline massif. Our study shows the involvement of crystalline basement from the former European Jurassic continental margin in two distinct events: a first extensional event coeval with Eggerian to Karpatian (ca. 28-16 Ma) thin-skinned thrusting reactivated the rift basement fault array and resulted from the large degree of lower plate bending promoted by high lateral gradients of lithospheric strength and slab pull forces. Slab-break off during the final stages of collision around Karpatian times (ca. 17-16 Ma) promoted large wavelength uplift and an excessive topographic load. This load was reduced by broadening the orogenic wedge through the reactivation of the lower plate deep detachment beneath and ahead of the thin-skinned thrust front (with the accompanying positive inversion of the basement fault array) and ultimately, by the collapse of the hinterland summits enhanced by transtensional faulting. Although this work specifically deals with the involvement of the basement in the Alpine-Carpathian Junction, the main conclusions are of general interest to the understanding of orogenic system

    Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Current and advanced act control system definition study, volume 1

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    An active controls technology (ACT) system architecture was selected based on current technology system elements and optimal control theory was evaluated for use in analyzing and synthesizing ACT multiple control laws. The system selected employs three redundant computers to implement all of the ACT functions, four redundant smaller computers to implement the crucial pitch-augmented stability function, and a separate maintenance and display computer. The reliability objective of probability of crucial function failure of less than 1 x 10 to the -9th power per flight of 1 hr can be met with current technology system components, if the software is assumed fault free and coverage approaching 1.0 can be provided. The optimal control theory approach to ACT control law synthesis yielded comparable control law performance much more systematically and directly than the classical s-domain approach. The ACT control law performance, although somewhat degraded by the inclusion of representative nonlinearities, remained quite effective. Certain high-frequency gust-load alleviation functions may require increased surface rate capability

    Quantum probabilities as Dempster-Shafer probabilities in the lattice of subspaces.

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    yesThe orthocomplemented modular lattice of subspaces L[H(d)] , of a quantum system with d-dimensional Hilbert space H(d), is considered. A generalized additivity relation which holds for Kolmogorov probabilities is violated by quantum probabilities in the full lattice L[H(d)] (it is only valid within the Boolean subalgebras of L[H(d)] ). This suggests the use of more general (than Kolmogorov) probability theories, and here the Dempster-Shafer probability theory is adopted. An operator D(H1,H2) , which quantifies deviations from Kolmogorov probability theory is introduced, and it is shown to be intimately related to the commutator of the projectors P(H1),P(H2) , to the subspaces H 1, H 2. As an application, it is shown that the proof of the inequalities of Clauser, Horne, Shimony, and Holt for a system of two spin 1/2 particles is valid for Kolmogorov probabilities, but it is not valid for Dempster-Shafer probabilities. The violation of these inequalities in experiments supports the interpretation of quantum probabilities as Dempster-Shafer probabilities

    Lower and upper probabilities in the distributive lattice of subsystems

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    yesThe set of subsystems ∑ (m) of a finite quantum system ∑(n) (with variables in Ζ(n)) together with logical connectives, is a distributive lattice. With regard to this lattice, the ℓ(m | ρn) = Tr ((m) ρn ) (where (m) is the projector to ∑(m)) obeys a supermodularity inequality, and it is interpreted as a lower probability in the sense of the Dempster–Shafer theory, and not as a Kolmogorov probability. It is shown that the basic concepts of the Dempster–Shafer theory (lower and upper probabilities and the Dempster multivaluedness) are pertinent to the quantum formalism of finite systems

    Secure Code Update for Embedded Devices via Proofs of Secure Erasure

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    Abstract. Remote attestation is the process of verifying internal state of a remote embedded device. It is an important component of many security protocols and applications. Although previously proposed re-mote attestation techniques assisted by specialized secure hardware are effective, they not yet viable for low-cost embedded devices. One no-table alternative is software-based attestation, that is both less costly and more efficient. However, recent results identified weaknesses in some proposed software-based methods, thus showing that security of remote software attestation remains a challenge. Inspired by these developments, this paper explores an approach that relies neither on secure hardware nor on tight timing constraints typi-cal of software-based technqiques. By taking advantage of the bounded memory/storage model of low-cost embedded devices and assuming a small amount of read-only memory (ROM), our approach involves a new primitive – Proofs of Secure Erasure (PoSE-s). We also show that, even though it is effective and provably secure, PoSE-based attestation is not cheap. However, it is particularly well-suited and practical for two other related tasks: secure code update and secure memory/storage erasure. We consider several flavors of PoSE-based protocols and demonstrate their feasibility in the context of existing commodity embedded devices.

    PfRH5: A Novel Reticulocyte-Binding Family Homolog of Plasmodium falciparum that Binds to the Erythrocyte, and an Investigation of Its Receptor

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    Multiple interactions between parasite ligands and their receptors on the human erythrocyte are a condition of successful Plasmodium falciparum invasion. The identification and characterization of these receptors presents a major challenge in the effort to understand the mechanism of invasion and to develop the means to prevent it. We describe here a novel member of the reticulocyte-binding family homolog (RH) of P. falciparum, PfRH5, and show that it binds to a previously unrecognized receptor on the RBC. PfRH5 is expressed as a 63 kDa protein and localized at the apical end of the invasive merozoite. We have expressed a fragment of PfRH5 which contains the RBC-binding domain and exhibits the same pattern of interactions with the RBC as the parent protein. Attachment is inhibited if the target cells are exposed to high concentrations of trypsin, but not to lower concentrations or to chymotrypsin or neuraminidase. We have determined the affinity, copy number and apparent molecular mass of the receptor protein. Thus, we have shown that PfRH5 is a novel erythrocyte-binding ligand and the identification and partial characterization of the new RBC receptor may indicate the existence of an unrecognized P. falciparum invasion pathwa

    Gliding Motility of Babesia bovis Merozoites Visualized by Time-Lapse Video Microscopy

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    BACKGROUND: Babesia bovis is an apicomplexan intraerythrocytic protozoan parasite that induces babesiosis in cattle after transmission by ticks. During specific stages of the apicomplexan parasite lifecycle, such as the sporozoites of Plasmodium falciparum and tachyzoites of Toxoplasma gondii, host cells are targeted for invasion using a unique, active process termed "gliding motility". However, it is not thoroughly understood how the merozoites of B. bovis target and invade host red blood cells (RBCs), and gliding motility has so far not been observed in the parasite. METHODOLOGY/PRINCIPAL FINDINGS: Gliding motility of B. bovis merozoites was revealed by time-lapse video microscopy. The recorded images revealed that the process included egress of the merozoites from the infected RBC, gliding motility, and subsequent invasion into new RBCs. The gliding motility of B. bovis merozoites was similar to the helical gliding of Toxoplasma tachyzoites. The trails left by the merozoites were detected by indirect immunofluorescence assay using antiserum against B. bovis merozoite surface antigen 1. Inhibition of gliding motility by actin filament polymerization or depolymerization indicated that the gliding motility was driven by actomyosin dependent process. In addition, we revealed the timing of breakdown of the parasitophorous vacuole. Time-lapse image analysis of membrane-stained bovine RBCs showed formation and breakdown of the parasitophorous vacuole within ten minutes of invasion. CONCLUSIONS/SIGNIFICANCE: This is the first report of the gliding motility of B. bovis. Since merozoites of Plasmodium parasites do not glide on a substrate, the gliding motility of B. bovis merozoites is a notable finding

    Zusammenfassung für Entscheidungstragende

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    Die Zusammenfassung für Entscheidungstragende fasst die Inhalte des APCC Special Report „Landnutzung und Klimawandel in Österreich“ in komprimierter Form zusammen. Im Lichte des Zusammenhanges von Landnutzung, Klimawandel und gesellschaftlichem Wohlergehen werden die gegenwärtige Situation und zukünftige Entwicklungen in Österreich synoptisch beschrieben, wesentliche Optionen der Klimawandelanpassung und des Klimaschutzes dargestellt, deren Trade-offs und Synergien systematisch beleuchtet und zentrale Einsichten zur Umsetzung von Strategien zum Klimaschutz und der Klimawandelanpassung in Österreich zusammengefasst
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