Heuristische Konfiguration und Scheduling für Echtzeitsysteme

In this paper we describe the scheduling of processes, threads and messages for a distributed hard-and software system (for air traffic control) which is supported by heuristics. Furthermore, we show how such application specific heuristics are linked to a reusable application framework.     

Soft eigenvalue assignment with limited disturbance feedforward and state controller norm

The method of softly assigning eigenvalues is attractive for design problems where constraining the control effort and disturbance feedforward is more important than following the exact pole location.     

CIRED 2001: Session 6 — Management, Organisation, Qualifikation

Ohne Zusammenfassung     

Properties of the translucent ceramics Nd: Y<Subscript>2</Subscript>O<Subscript>3</Subscript> prepared by pulsed compaction and sintering of weakly aggregated nanopowders

A translucent cubic yttria ceramic material doped by neodymium, namely, 1Nd: Y₂O₃, with particles of micrometer size (5–17 μm) and clearly defined boundaries is synthesized from nanopowders prepared by laser-induced evaporation with the use of magnetic pulsed compaction and vacuum sintering. Owing to the high activity of nanoparticles, the sintering is performed at temperatures below 1750°C without densifying additives. An increase in the sintering temperature to 900°C leads to an increase in the visual transparency of the ceramic materials and a decrease in the radiation attenuation coefficient. The samples of the translucent ceramics are characterized by rather large values of the microhardness (11.8 GPa) and the fracture toughness as compared to those of single crystals of the same composition. The fracture toughness of the ceramic material increases by a factor of approximately 2.5 with a decrease in the average crystallite size from 5.0 to 0.6 μm.     

Electrical and photoelectric properties of polycrystalline textured CdTe

The temperature dependences of the resistivity and photoconductivity spectra of polycrystalline coarse-grained stoichiometric CdTe purified in the process of repeated recrystallization at temperatures two times lower than melting point were studied; CdTe ingots were synthesized from starting components subjected profound purification. It is shown that the main characteristics of polycrystals (resistivity, and the lifetime and mobility of carriers) are determined by composite complexes formed as a result of interaction between extended and point defects. The values of the product of mobility multiplied by lifetime are determined.     

Persönliches

Ohne Zusammenfassung     

Finite-Elemente-Analyse einer Transversalflussmaschine

An efficient and resource saving method to generate the different angular rotor positions of a transverse flux machine with a 3D finite element model is presented. The calculations are performed with the superelement analysis of the EMAS solver. From the magnetostatic results the torque-position relationships and the stray field energy in the rotor shaft are evaluated in the steady state condition for different values of the excitation current.     

Structure and Properties of La0.6Sr0.4 – xBaxMnO3 (0 ≤ x ≤ 0.4) Magnetoresistive Ceramics

The effect of Ba content on the phase composition, lattice parameter, ⁵⁵Mn NMR spectrum, resistance, and magnetoresistance of La_0.6Sr_{0.4 – x} Ba _x MnO₃ perovskites was studied. The lattice parameter of the single-phase ceramic samples was found to increase with increasing x. The tolerance factor increases and the ionic field strength decreases asx increases from 0 to 0.4. The ⁵⁵Mn NMR results obtained at 77 K indicate a high-frequency electron exchange between Mn³⁺ and Mn⁴⁺ in the ferromagnetic phase. The peak-magnetoresistance temperature tends to decrease with increasing x. The magnetoresistance of the ceramics is correlated with the bond covalence. It is inferred that the ceramics contain inhomogeneities differing in nature and length scale (macroscopic, mesoscopic, and microscopic), which influence their magnetoresistance.     

Extending the life of free-wheel ratchet mechanisms by backup of the working components

A method is proposed for extending the life of free-wheel ratchet mechanisms by backup of the pawls. Comparative assessments are presented.