A method and an apparatus for tracking uncertain signals in the simulation of chip design are provided. Provided compounds and pharmaceutical compositions thereof are useful for the prevention and treatment of a variety of conditions in mammals including humans, including by way of non-limiting example, pain, inflammation, cognitive disorders, anxiety, depression, and others. The line is fixedly engaged with an anchor on one side of the wound while the tensioning apparatus provides tension on the line to draw the skin anchor and the tensioning apparatus toward each other and toward the wound. The intermediate layer has a cubic structure and the chromium-containing functional layer is selected from chromium oxide, chromium oxynitride, aluminium-chromium oxide 2O3, aluminium-chromium oxynitride or a mixed oxide or mixed oxynitride of aluminium, chromium and further metals of 2 oxide or 2 oxynitride, where Me. The wireless communication system can provide additional channel estimation resources by inserting dedicated pilot channels into one or more of the frequencies allocated to symbols for the receiver.