Energy (signal processing)
In signal processing, the energy 
of a continuous-time signal x(t) is defined as
the energy of a discrete-time signal x(t) is defined as
Relationship to energy in physics
Energy in this context is not, strictly speaking, the same as the conventional notion of energy in physics and the other sciences. The two concepts are, however, closely related, and it is possible to convert from one to the other:
For example, if x(t) represents the potential (in volts) of an electrical signal propagating across a transmission line, then Z would represent the characteristic impedance (in ohms) of the transmission line. The units of measure for the signal energy would appear as volt2·seconds, which is not dimensionally correct for energy in the sense of the physical sciences. After dividing by Z, however, the dimensions of E would become volt2·seconds per ohm, which is equivalent to joules, the SI unit for energy as defined in the physical sciences.
Spectral energy density
Seven Year Itch (Collective Soul album)
On September 18, 2001, Collective Soul released their greatest hits compilation Seven Year Itch: Greatest Hits, 1994-2001 (stylized as 7even Year Itch). The compilation includes songs recorded from 1994 to 2001 and included two new tracks; "Next Homecoming" and "Energy". Seven Year Itch received decent reviews and was relatively successful It sold 225,000 copies in the first year after its release and reached number fifty on the Billboard 200; in Canada, it reached number nine on its albums chart and went platinum. All the songs in Seven Year Itch had charted in the US on the Billboard Hot 100, Mainstream Rock Tracks, or the Modern Rock Tracks chart, except for "Energy", which debuted in this compilation.
The compilation has sold over 500,000 copies. It saw a resurgence in sales after Collective Soul began putting out albums on their own independent label, El Music Group, beginning in 2004.
Seven Year Itch was the last album Collective Soul released through Atlantic Records and their last album to feature guitarist Ross Childress, who had been with the band since its 1993/1994 debut.
Energy (Drake song)
"Energy" is the second single by Canadian rapper Drake from his fourth commercial release If You're Reading This It's Too Late.
Composition
"Energy" contains samples from Eazy-Duz-It performed by Eazy-E and Ridin Spiners performed by Three 6 Mafia. Energy was produced by Boi-1da and OB O'Brien. According to WhoSampled the song samples the score of an episode of The O.C..
Critical reception
"Energy" received acclaim from music critics with many calling it the best song of the album. Ryan Dombal of Pitchfork gave the song a positive review and named it "Best New Track", stating "The song isn't aimed to any rappers or pop stars, not Kendrick Lamar, Big Sean or Tyga, but the song lines are dangerous."
Music video
Release
The video of "Energy" was released on Apple Music and users with iTunes and registered Apple Music account can watch this video.
Synopsis
Zenith (building)
The Zenith is a culture and exhibition centre, converted from an old railway reparation hall, located in Freimann, Munich, Germany.
The centre hosts concerts, fairs, company presentations and parties. The centre can hold up to six thousand people and has a floor area of 5046 m². The main stage is 24×16 metres in area. Its capacity is approximately 7,000 people
History
The building is of a unique architectural style, and formerly served as a railway construction and reparation hall. It was originally built from 1916 to 1918. The building is protected.
External links
References
Coordinates: 48°11′41″N 11°36′30″E / 48.19472°N 11.60833°E / 48.19472; 11.60833
Zenith camera
A zenith camera is an astrogeodetic telescope used today primarily for the local surveys of Earth's gravity field. Zenith cameras are designed as transportable field instruments for the direct observation of the plumb line (astronomical coordinates) and vertical deflections.
Instrument
A zenith camera combines an optical lens (about 10–20 cm aperture) with a digital image sensor (CCD) in order to image stars near the zenith. Electronic levels (tilt sensors) serve as a means to point the lens towards zenith. Zenith cameras are generally mounted on a turnable platform to allow star images to be taken in two camera directions (two-face-measurement). Because zenith cameras are usually designed as non-tracking and non-scanning instruments, exposure times are kept short, at the order of few 0.1 s, yielding rather circular star images. Exposure epochs are mostly recorded by means of the timing-capability of GPS-receivers (time-tagging).
Data processing
Depending on the CCD sensor - lens combination used, few 10s to 100s of stars are captured with a single digital zenith image. The positions of imaged stars are measured by means of digital image processing algorithms, such as image moment analysis or point spread functions to fit the star images. Star catalogues, such as Tycho-2 or UCAC-3 are used as celestial reference to reduce the star images. The zenith point is interpolated into the field of imaged stars, and corrected for the exposure time and (small) tilt of the telescope axis to yield the direction of the plumb line.
Zenith (disambiguation)
The zenith is the point in the sky that appears directly above the observer (opposite: nadir).
Zenith may also refer to:
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