Time filter

Source Type

Braunschweig, Germany

Hernandez-Gonzalez M.,CINVESTAV | Alanis A.Y.,University of Guadalajara | Hernandez-Vargas E.A.,HZI
Applied Soft Computing Journal

Control design for helicopters is a complicated and challenging problem due to the strong inter-couplings and nonlinear uncertainties in the system model. This paper deals with the decentralized control problem for the output trajectory tracking in a Quanser 2 degree of freedom (DOF) helicopter. High order neural network (HONN) is an important technique to approximate non-linearities in the model. Two different discrete-time schemes with a decentralized structure are used. Neural backstepping and neural sliding mode block control techniques are considered in order to control pitch and yaw positions. On one hand, backstepping control divides the whole system into two subsystems which are used to track the pitch and yaw references respectively. Real and virtual controls are approximated by HONNs. On the other hand, block control technique is applied to HONNs which can identify the system helicopter model. Each discrete-time high order neural network is trained on-line with an extended Kalman filter based algorithm. Without the previous knowledge of the plant parameters neither its model, we show via simulations the good performance of both strategies. The block control technique presents slightly better results than backstepping algorithm. © 2011 Elsevier B.V. Source

Hemmen K.,HZI | Reinl T.,Helmholtz Center for Infection Research | Buttler K.,University of Gottingen | Behler F.,HZI | And 4 more authors.

Recently, we isolated and characterized resident endothelial progenitor cells from the lungs of adult mice. These cells have a high proliferation potential, are not transformed and can differentiate into blood- and lymph-vascular endothelial cells under in vitro and in vivo conditions. Here we studied the secretome of these cells by nanoflow liquid chromatographic mass spectrometry (LC-MS). For analysis, 3-day conditioned serum-free media were used. We found 133 proteins belonging to the categories of membrane-bound or secreted proteins. Thereby, several of the membrane-bound proteins also existed as released variants. Thirty-five proteins from this group are well known as endothelial cell- or angiogenesis-related proteins. The MS analysis of the secretome was supplemented and confirmed by fluorescence activated cell sorting analyses, ELISA measurements and immunocytological studies of selected proteins. The secretome data presented in this study provides a platform for the in-depth analysis of endothelial progenitor cells and characterizes potential cellular markers and signaling components in hem- and lymphangiogeneis. © 2010 Springer Science+Business Media B.V. Source

Discover hidden collaborations