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

Token Racing

Token Racing was a short-lived Formula One team and constructor from the United Kingdom, participating in four Grands Prix of the 1974 Formula One season.

Token's history began in late 1973 when Rondel Racing, the successful Formula Two team founded by Ron Dennis and Neil Trundle, decided to enter F1. Dennis asked Ray Jessop to design the car, while backing was to come from the French oil company Motul, which had sponsored the team for the previous two years. But when the 1973 oil crisis hit, Motul withdrew, and Dennis was forced to close down the team. The F1 project was subsequently sold to shipbroker Tony Vlassopulo and Lloyd's underwriter Ken Grob, from whose first names the "Token" name was derived, while the car was called the RJ02 in honour of Jessop.

The team made its F1 debut in April 1974 at the non-Championship International Trophy race at Silverstone, with Welshman Tom Pryce at the wheel. Its first Championship race came the following month, at the Belgian Grand Prix, where Pryce qualified 20th but retired at three-quarter distance following a collision with Jody Scheckter's Tyrrell. The team entered the next race at Monaco but was forbidden from taking part on the basis of Pryce's supposed inexperience, prompting the Welshman to move to the Shadow team.

Access token

In computer systems, an access token contains the security credentials for a login session and identifies the user, the user's groups, the user's privileges, and, in some cases, a particular application.

Overview

An access token is an object encapsulating the security identity of a process or thread. A token is used to make security decisions and to store tamper-proof information about some system entity. While a token is generally used to represent only security information, it is capable of holding additional free-form data that can be attached while the token is being created. Tokens can be duplicated without special privilege, for example to create a new token with lower levels of access rights to restrict the access of a launched application. An access token is used by Windows when a process or thread tries to interact with objects that have security descriptors (securable objects). An access token is represented by the system object of type Token.

An access token is generated by the logon service when a user logs on to the system and the credentials provided by the user are authenticated against the authentication database. The authentication database contains credential information required to construct the initial token for the logon session, including its user id, primary group id, all other groups it is part of, and other information. The token is attached to the initial process created in the user session and inherited by subsequent processes created by the initial process. Whenever such a process opens a handle to any resource which has access control enabled, Windows reconciles the data in the target object's security descriptor with the contents of the current effective access token. The result of this access check evaluation is an indication of whether any access is allowed and, if so, what operations (read, write/modify, etc.) the calling application is allowed to perform.

Token coin

In the study of numismatics, tokens are coin-like objects used instead of coins. The field of tokens is part of exonumia. Tokens are used in place of coins and either have a denomination shown or implied by size, color or shape. "Tokens" are often made of cheaper metals: copper, pewter, aluminium, brass and tin were commonly used, while bakelite, leather, porcelain, and other less durable materials are also known.

The key point of difference between a token and a coin is that a coin is issued by a governmental local or national authority and is freely exchangeable for goods or other coins, whereas a token has a much more limited use and is often (but not always) issued by a private company, group, association or individual.

In the case of "currency tokens" issued by a company but also recognized by the State there is a convergence between tokens and currency.

Currency tokens

In their purest form, currency tokens issued by a company crossed the boundary of merely being "trade" tokens when they were sanctioned by the local government authority. This was sometimes a measure resulting from a severe shortage of money or the government's inability to issue its own coinage. In effect, the organization behind the tokens became the regional bank.