Color

Color (American English) or colour (Commonwealth English) is the visual perceptual property corresponding in humans to the categories called red, blue, yellow, etc. Color derives from the spectrum of light (distribution of light power versus wavelength) interacting in the eye with the spectral sensitivities of the light receptors. Color categories and physical specifications of color are also associated with objects or materials based on their physical properties such as light absorption, reflection, or emission spectra. By defining a color space colors can be identified numerically by their coordinates.

Because perception of color stems from the varying spectral sensitivity of different types of cone cells in the retina to different parts of the spectrum, colors may be defined and quantified by the degree to which they stimulate these cells. These physical or physiological quantifications of color, however, do not fully explain the psychophysical perception of color appearance.

The science of color is sometimes called chromatics, colorimetry, or simply color science. It includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range (that is, what we commonly refer to simply as light).

DEF CON

DEF CON (also written as DEFCON or Defcon) is one of the world's largest annual hacker conventions, held every year in Las Vegas, Nevada. The first DEF CON took place in June 1993.

Many of the attendees at DEF CON include computer security professionals, journalists, lawyers, federal government employees, security researchers, and hackers with a general interest in software, computer architecture, phone phreaking, hardware modification, and anything else that can be "cracked." The event consists of several tracks of speakers about computer- and cracking-related subjects, as well as social events Wargames and contests in everything from creating the longest Wi-Fi connection and cracking computer systems to who can most effectively cool a beer in the Nevada heat. Other contests, past and present, include lockpicking, robotics-related contests, art, slogan, coffee wars, scavenger hunt and Capture the Flag. Capture the Flag (CTF) is perhaps the best known of these contests. It is a hacking competition where teams of crackers attempt to attack and defend computers and networks using certain software and network structures. CTF has been emulated at other cracking conferences as well as in academic and military contexts.