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

Package (UML)

A package in the Unified Modeling Language is used "to group elements, and to provide a namespace for the grouped elements". A package may contain other packages, thus providing for a hierarchical organization of packages.

Pretty much all UML elements can be grouped into packages. Thus, classes, objects, use cases, components, nodes, node instances etc. can all be organized as packages, thus enabling a manageable organization of the myriad elements that a real-world UML model entails.

Usage

When organizing functional models (use case models, workflow models etc.), use packages to model the real-world modular structure of the system being modeled. When organizing source code, use packages to represent the different layers of the source code. For instance:

When organizing component models, use packages to group the components according to ownership and/or reuse possibilities. For instance:

Software package

Software package may refer to:

See also

Package manager

A package manager or package management system is a collection of software tools that automates the process of installing, upgrading, configuring, and removing computer programs for a computer's operating system in a consistent manner. A package manager deals with packages, distributions of software and data in archive files. Packages contain metadata, such as the software's name, description of its purpose, version number, vendor, checksum, and a list of dependencies necessary for the software to run properly. Upon installation, metadata is stored in a local package database. Package managers typically maintain a database of software dependencies and version information to prevent software mismatches and missing prerequisites. They work closely with software repositories and app stores.

Package managers are designed to save organizations time and money through remote administration and software distribution technology that eliminate the need for manual installs and updates. This can be particularly useful for large enterprises whose operating systems are based on Linux and other Unix-like systems, typically consisting of hundreds or even tens of thousands of distinct software packages; in the former case, a package manager is a convenience, in the latter case it becomes essential.