Mobile webThe mobile web refers to mobile browser-based World Wide Web services accessed from handheld mobile devices, such as smartphones or feature phones, through a mobile or other wireless network. Traditionally, the World Wide Web has been accessed via fixed-line services on laptops and desktop computers. However, the web is now more accessible by portable and wireless devices. Early 2010 ITU (International Telecommunication Union) report said that with current growth rates, web access by people on the go - via laptops and smart mobile devices - was likely to exceed web access from desktop computers within the following five years.
Envelope (waves)In physics and engineering, the envelope of an oscillating signal is a smooth curve outlining its extremes. The envelope thus generalizes the concept of a constant amplitude into an instantaneous amplitude. The figure illustrates a modulated sine wave varying between an upper envelope and a lower envelope. The envelope function may be a function of time, space, angle, or indeed of any variable.
Oscillator representationIn mathematics, the oscillator representation is a projective unitary representation of the symplectic group, first investigated by Irving Segal, David Shale, and André Weil. A natural extension of the representation leads to a semigroup of contraction operators, introduced as the oscillator semigroup by Roger Howe in 1988. The semigroup had previously been studied by other mathematicians and physicists, most notably Felix Berezin in the 1960s. The simplest example in one dimension is given by SU(1,1).
