Variable Schrittweitensteuerungen für die Homotopiemethode bei adäquaten nichtlinearen Ausgleichsproblemen

For adequate models of nonlinear regression the homotopy method is shown to enlarge the region of convergence of the ordinary Gauss-Newton-Method theoretically as well as practically. Two methods to control the stepsize are proposed: the first one is in analogy to the empirically based ?doubling-/bisecting-” damping strategy for the relaxed Newton Method and the other one is based upon more local information of the function. Both methods are shown to be effective with practical problems and improve the old method of a constant stepsize; in addition the second method can follow the homotopy path and can even detect it's singularities. In case of a system of nonlinear equations both methods reduce to a stepsize control for the embedded Newton method.     

Ein Vergleich von Methoden zur Kurzfristprognose elektrischer Last

Übersicht Die Prognose des Lastverbrauches ist ein wichtiges Hilfsmittel der Energieversorgungsunternehmen, den Kraftwerkseinsatz zu planen und zu optimieren. Diese Arbeit stellt Prognosemodelle und verschiedene Prognoseverfahren, wie z. B. die Kleinst-Quadrate-Methode, adaptive Schätzverfahren und die Karhunen-Loève-Entwicklung, dar. Diese Verfahren werden auf ihre Prognosequalität hin miteinander verglichen.

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Comparison of methods for short-term load forecasting

Contents Short-term load forecasting is an important instrument for scheduling and optimizing the use of different power-stations. This article describes forecasting-models and forecasting-methods, as the Least-squares method, adaptive methods and the Karhunen-Loève-expansion. The accuracy of the forecasts using these methods is compared.

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Diese Arbeit wurde zum Teil im Rahmen des Projektes S32/02 des Fonds zur Förderung der wissenschaftlichen Forschung finanziert.     

Comparison and Applications of DPV-2000 and Accuraspray-g3 Diagnostic Systems

Comparative in-flight measurements of particles plasma sprayed by F4 and Triplex II guns were carried out using the diagnostic systems DPV-2000 and Accuraspray-g3. The comparison of mean particle velocities and temperatures as well as intensity profiles of the plume show a good agreement confirming their accuracy. However, the varying operating principles especially the deceased dimensions of the measurement volumes have to be considered carefully when evaluating the results. Furthermore, some applications of the diagnostic systems DPV-2000 and Accuraspray-g3 are shown. Finally some application limits, which were identified for certain powder compositions at higher plasma power levels will be discussed.     

High-molecular weight diepoxide-dicarboxylic acid addition polymers

Summary The addition polymerization of 2,2-bis[4-(2,3-epoxypropoxy)phenyl] propane (DGEBA) and dicarboxylic acid results in high molecular weight addition polymers (M_n 8000–13000). Their molecular weight distribution is rather broad (M_w/M_n=11,6) due to side reactions such as transesterification and formation of ether linkages. Due to the incorporation of the aliphatic dicarboxylic acid moieties in the polymer backbone, the addition polymers show relatively low glass transition temperatures ranging from 26 to 45 °C.     

Selforganization of Alkali Metal on a Catalytic Metal Surface

Oxidized diamond-supported Ni catalysts gave the best performance among the oxidized diamond-supported various metal catalysts for the decomposition of methanol to synthesis gas. Ni (5 wt%)/oxidized diamond afforded 82.5% conversion of methanol to give a CO to H₂ ratio of 1.7 at 573 K.