http://nova.newcastle.edu.au/vital/access/services/Feed ${session.getAttribute("locale")} 5 Sparse command generator for remote control http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:10675 In this article, we consider remote-controlled systems, where the command generator and the controlled object are connected with a bandwidth-limited communication link. In the remote-controlled systems, efficient representation of control commands is one of the crucial issues because of the bandwidth limitations of the link. We propose a new representation method for control commands based on compressed sensing. In the proposed method, compressed sensing reduces the number of bits in each control signal by representing it as a sparse vector. The compressed sensing problem is solved by an ℓ1-ℓ2 optimization, which can be effectively implemented with an iterative shrinkage algorithm. A design example also shows the effectiveness of the proposed method. 2013-03-24T04:52:39.481Z ]]> High-speed vertical positioning for contact-mode atomic force microscopy http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8713 Many popular modes of scanning probe microscopy require a vertical feedback system to regulate the tip-sample interaction. Unfortunately the vertical feedback controller imposes a severe limit on the scan-speed of scanning probe microscopes. In this paper, the foremost bandwidth limitation is identified to be the low-frequency mechanical resonances of the scanner. To overcome this limitation, a dual-stage vertical positioner is proposed. In this work, the bandwidth of a contact-mode atomic force microscope is increased from 83 Hz to 2.7 kHz. This improvement allows image quality to be retained with a speed increase of 33 times, or alternatively, feedback error can be reduced by 33 times if scan speed is not increased. 2013-02-27T04:20:03.107Z ]]>