Category: Dictionary

ABEND

An abnormal end to a computer job. An abend (a combining of two words, abnormal end, when operator messages were as short as possible) is an abnormal, rather than planned, end or termination of a computer program because of some…

ABSOLUTE PERMISSIVE BLOCK

A block within which the movement of trains on a desigated section of track or tracks is directed by signals automatically controlled and without train-order authority and without superiority of trains.

ABSTRACT CHOICE MODEL

A model based on the assumption that it is not necessary to identify travel choice variables by the name of their mode, destination, time of day, or other characteristic; instead, they are identified by their attributes, for example, variables describing…

ACCEPTABLE QUALITY LEVEL

For a given quality characteristic, that minimum level of actual quality at which the material or construction can be considered fully acceptable.

ACCEPTANCE TESTING

Testing concerned with proving the effectiveness of new equipment prior to placing said equipment into operating service.

ACCESS BOARD

The U.S. Access Board is an independent Federal agency devoted to accessibility for people with disabilities. It is a leading source of information on accessible design

ACCESS CONTROL

The process by which access to resources of a computer system is limited or controlled. A logical or physical control designed to protect against unauthorized entry or use.