In engineering, a requirement is a singular documented physical and functional need that a particular product or service must be or perform. It is most commonly used in a formal sense in systems engineering, software engineering, or enterprise engineering. It is a statement that identifies a necessary attribute, capability, characteristic, or quality of a system for it to have value and utility to a user.

In the classical engineering approach, sets of requirements are used as inputs into the design stages of product development. Requirements are also an important input into the verification process, since tests should trace back to specific requirements. Requirements show what elements and functions are necessary for the particular project. This is reflected in the waterfall model of the software life-cycle. However, when iterative methods of software development or agile methods are used, the system requirements are incrementally developed in parallel with design and implementation.

Requirements engineering is the set of activities that lead to the derivation of the system or software requirements. Requirements engineering may involve a feasibility study, or a conceptual analysis phase of the project and requirements elicitation (gathering, understanding, reviewing, and articulating the needs of the stakeholders) and requirements analysis,analysis (checking for consistency and completeness), specification (documenting the requirements) and validation (making sure the specified requirements are correct).

Philip David Charles "Phil" Collins, LVO (born 30 January 1951) is an English singer-songwriter, drummer, pianist and actor best known as a drummer and vocalist for British progressive rock group Genesis and as a solo artist.

Collins sang the lead vocals on several chart hits in the United Kingdom and the United States between 1975 and 2010, either as a solo artist or with Genesis. His singles, sometimes dealing with lost love, ranged from the drum-heavy "In the Air Tonight", dance pop of "Sussudio", piano-driven "Against All Odds", to the political statements of "Another Day in Paradise".

Collins's professional music career began as a drummer, originally in a band called The Real Thing with Andrea Bertorelli, who later became his first wife. Collins played drums and shared lead vocals (with Brian Chatton) in Flaming Youth which recorded one album, (Ark II). In 1970, he took over drums for Genesis, which had already recorded two albums. In Genesis, Collins originally supplied backing vocals for front man Peter Gabriel, singing lead on only two songs: "For Absent Friends" from 1971's Nursery Cryme album and "More Fool Me" from Selling England by the Pound, which was released in 1973. Following Gabriel's departure in 1975, Collins became the group's lead singer.

Lauren Ogilvie "Lo" Bosworth (born September 29, 1986) is an American television personality and author. She is best known for her appearances on the MTV reality series Laguna Beach: The Real Orange County and its spin-off, The Hills.

Bosworth was born on September 29, 1986 and grew up in Laguna Beach, CA, before moving to Los Angeles, CA. Bosworth is a graduate of UCLA, where she was a member of Kappa Kappa Gamma Sorority and majored in Art History.

Bosworth first appeared on the MTV reality series Laguna Beach: The Real Orange County alongside best friend Lauren Conrad and former classmates, Stephen Colletti and Kristin Cavallari. Throughout the series, she and her friend's lives were filmed during their senior year of high school, as well as the summer prior to college. She appeared as a regular in the first season, and made a couple of appearances in the second.

After Laguna Beach, Lauren Conrad (Bosworth's best friend since elementary school) went on to star in its spin-off, The Hills. However, the pair were not on speaking terms for the early stages of production. As a result, Bosworth was not added as a secondary cast member until the second season, after she and Lauren had reconciled. This rift in Conrad and Bosworth's friendship was only briefly mentioned on The Hills. The only details given were that the two did not speak for nearly two years due to a fight caused by Jen Bunney, a mutual friend who has made several appearances on the program.

Leonard Norman Cohen, CC GOQ (born 21 September 1934) is a Canadian singer-songwriter, musician, poet, and novelist. His work often explores religion, isolation, sexuality, and interpersonal relationships. Cohen has been inducted into the American Rock and Roll Hall of Fame and both the Canadian Music Hall of Fame and the Canadian Songwriters Hall of Fame. He is also a Companion of the Order of Canada, the nation's highest civilian honour.

While giving the speech at Cohen's induction into the Rock and Roll Hall of Fame on 10 March 2008, Lou Reed described Cohen as belonging to the "highest and most influential echelon of songwriters."

Cohen was born on 21 September 1934 in Westmount, Montreal, Quebec, into a middle-class Jewish family. He attended Roslyn Elementary School. His mother, Marsha Klinitsky, of Lithuanian Jewish ancestry, emigrated from Lithuania while his great-grandfather emigrated from Poland. He grew up in Westmount on the Island of Montreal. His grandfather was Lyon Cohen, founding president of the Canadian Jewish Congress. His father, Nathan Cohen, who owned a substantial Montreal clothing store, died when Cohen was nine years old. On the topic of being a Kohen, Cohen has said that, "I had a very Messianic childhood." He told Richard Goldstein in 1967. "I was told I was a descendant of Aaron, the high priest." Cohen attended Westmount High School, beginning in 1948 where he was involved with the Student Council and studied music and poetry. He became especially interested in the poetry of Federico Garcia Lorca. As a teenager, he learned to play the guitar, and formed a country-folk group called the Buckskin Boys. Although he initially played a regular acoustic guitar as a teenager, he soon switched to playing a classical guitar after meeting a young Spanish flamenco guitar player who taught him "a few chords and some flamenco."