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A Worst-Case Analysis Of Direct-Sequence Spread-Spectrum In Multipath Channels, Murad Hizlan, Xuedong Liu
A Worst-Case Analysis Of Direct-Sequence Spread-Spectrum In Multipath Channels, Murad Hizlan, Xuedong Liu
Electrical and Computer Engineering Faculty Publications
We consider a direct-sequence spread-spectrum system operating in an indoors environment in the presence of multiaccess and multipath interference, and additive white Gaussian noise. We focus on the worst-case bit error probability of this system with a constraint on signal-to-interference ratio, and derive a Chernoff-type upper bound on this error probability. We evaluate the upper bound for a special case in order to gain understanding of the basic worst-case performance. We also compare the effects of the worst-case multipath interference with those of the worst-case multiuser interference of …
On-Line Free Form Surface Measurement Via A Fuzzy-Logic Controlled Scanning Probe, Ming Chang, Paul P. Lin
On-Line Free Form Surface Measurement Via A Fuzzy-Logic Controlled Scanning Probe, Ming Chang, Paul P. Lin
Mechanical Engineering Faculty Publications
This paper presents a system and methodology for on-line free form surface measurement via a scanning contact probe installed on a CNC (computer numerical control) machine. The scanning probe provides more sampling points than any traditional touch trigger type of probes used on CNC machines, and better measuring accuracy than laser displacement sensing or structured lighting. The presented measuring system's main advantage is that the number of measured points can vary with the change of surface curvature. To improve the measuring stability and continuity, fuzzy logic control, in lieu of traditional PID control, is employed. As a result, the …