Physical securityPhysical security describes security measures that are designed to deny unauthorized access to facilities, equipment, and resources and to protect personnel and property from damage or harm (such as espionage, theft, or terrorist attacks). Physical security involves the use of multiple layers of interdependent systems that can include CCTV surveillance, security guards, protective barriers, locks, access control, perimeter intrusion detection, deterrent systems, fire protection, and other systems designed to protect persons and property.
Security guardA security guard (also known as a security inspector, security officer, factory guard, or protective agent) is a person employed by a government or private party to protect the employing party's assets (property, people, equipment, money, etc.) from a variety of hazards (such as crime, waste, damages, unsafe worker behavior, etc.) by enforcing preventative measures.
Computational complexity theoryIn theoretical computer science and mathematics, computational complexity theory focuses on classifying computational problems according to their resource usage, and relating these classes to each other. A computational problem is a task solved by a computer. A computation problem is solvable by mechanical application of mathematical steps, such as an algorithm. A problem is regarded as inherently difficult if its solution requires significant resources, whatever the algorithm used.
Instant messagingInstant messaging (IM) technology is a type of online chat allowing real-time text transmission over the Internet or another computer network. Messages are typically transmitted between two or more parties, when each user inputs text and triggers a transmission to the recipient(s), who are all connected on a common network. It differs from email in that conversations over instant messaging happen in real-time (hence "instant").
Group schemeIn mathematics, a group scheme is a type of object from algebraic geometry equipped with a composition law. Group schemes arise naturally as symmetries of schemes, and they generalize algebraic groups, in the sense that all algebraic groups have group scheme structure, but group schemes are not necessarily connected, smooth, or defined over a field. This extra generality allows one to study richer infinitesimal structures, and this can help one to understand and answer questions of arithmetic significance.
Scheme (mathematics)In mathematics, a scheme is a mathematical structure that enlarges the notion of algebraic variety in several ways, such as taking account of multiplicities (the equations x = 0 and x2 = 0 define the same algebraic variety but different schemes) and allowing "varieties" defined over any commutative ring (for example, Fermat curves are defined over the integers). Scheme theory was introduced by Alexander Grothendieck in 1960 in his treatise "Éléments de géométrie algébrique"; one of its aims was developing the formalism needed to solve deep problems of algebraic geometry, such as the Weil conjectures (the last of which was proved by Pierre Deligne).
Cryptographic hash functionA cryptographic hash function (CHF) is a hash algorithm (a map of an arbitrary binary string to a binary string with a fixed size of bits) that has special properties desirable for a cryptographic application: the probability of a particular -bit output result (hash value) for a random input string ("message") is (as for any good hash), so the hash value can be used as a representative of the message; finding an input string that matches a given hash value (a pre-image) is unfeasible, assuming all input str
Hash chainA hash chain is the successive application of a cryptographic hash function to a piece of data. In computer security, a hash chain is a method used to produce many one-time keys from a single key or password. For non-repudiation, a hash function can be applied successively to additional pieces of data in order to record the chronology of data's existence. A hash chain is a successive application of a cryptographic hash function to a string .
Fast foodFast food is a type of mass-produced food designed for commercial resale, with a strong priority placed on speed of service. It is a commercial term, limited to food sold in a restaurant or store with frozen, preheated or precooked ingredients and served in packaging for take-out/takeaway. Fast food was created as a commercial strategy to accommodate large numbers of busy commuters, travelers and wage workers. In 2018, the fast food industry was worth an estimated $570 billion globally.
Fast-food restaurantA fast-food restaurant, also known as a quick-service restaurant (QSR) within the industry, is a specific type of restaurant that serves fast-food cuisine and has minimal table service. The food served in fast-food restaurants is typically part of a "meat-sweet diet", offered from a limited menu, cooked in bulk in advance and kept hot, finished and packaged to order, and usually available for take away, though seating may be provided.
