Quantum complexity theoryQuantum complexity theory is the subfield of computational complexity theory that deals with complexity classes defined using quantum computers, a computational model based on quantum mechanics. It studies the hardness of computational problems in relation to these complexity classes, as well as the relationship between quantum complexity classes and classical (i.e., non-quantum) complexity classes. Two important quantum complexity classes are BQP and QMA.
Component (graph theory)In graph theory, a component of an undirected graph is a connected subgraph that is not part of any larger connected subgraph. The components of any graph partition its vertices into disjoint sets, and are the induced subgraphs of those sets. A graph that is itself connected has exactly one component, consisting of the whole graph. Components are sometimes called connected components. The number of components in a given graph is an important graph invariant, and is closely related to invariants of matroids, topological spaces, and matrices.
Global variableIn computer programming, a global variable is a variable with global scope, meaning that it is visible (hence accessible) throughout the program, unless shadowed. The set of all global variables is known as the global environment or global state. In compiled languages, global variables are generally static variables, whose extent (lifetime) is the entire runtime of the program, though in interpreted languages (including command-line interpreters), global variables are generally dynamically allocated when declared, since they are not known ahead of time.
CyberattackA cyberattack is any offensive maneuver that targets computer information systems, computer networks, infrastructures, personal computer devices, or smartphones. An attacker is a person or process that attempts to access data, functions, or other restricted areas of the system without authorization, potentially with malicious intent. Depending on the context, cyberattacks can be part of cyber warfare or cyberterrorism. A cyberattack can be employed by sovereign states, individuals, groups, societies or organizations and it may originate from an anonymous source.
Graph powerIn graph theory, a branch of mathematics, the kth power G^k of an undirected graph G is another graph that has the same set of vertices, but in which two vertices are adjacent when their distance in G is at most k. Powers of graphs are referred to using terminology similar to that of exponentiation of numbers: G^2 is called the square of G, G^3 is called the cube of G, etc. Graph powers should be distinguished from the products of a graph with itself, which (unlike powers) generally have many more vertices than the original graph.
Proactive cyber defenceProactive cyber defence, means acting in anticipation to oppose an attack through cyber and cognitive domains. Proactive cyber defence can be understood as options between offensive and defensive measures. It includes interdicting, disrupting or deterring an attack or a threat's preparation to attack, either pre-emptively or in self-defence. Proactive cyber defence differs from active defence, in that the former is pre-emptive (does not waiting for an attack to occur).
Distance-regular graphIn the mathematical field of graph theory, a distance-regular graph is a regular graph such that for any two vertices v and w, the number of vertices at distance j from v and at distance k from w depends only upon j, k, and the distance between v and w. Some authors exclude the complete graphs and disconnected graphs from this definition. Every distance-transitive graph is distance-regular. Indeed, distance-regular graphs were introduced as a combinatorial generalization of distance-transitive graphs, having the numerical regularity properties of the latter without necessarily having a large automorphism group.
Loose couplingIn computing and systems design, a loosely coupled system is one in which components are weakly associated (have breakable relationships) with each other, and thus changes in one component least affect existence or performance of another component. in which each of its components has, or makes use of, little or no knowledge of the definitions of other separate components. Subareas include the coupling of classes, interfaces, data, and services. Loose coupling is the opposite of tight coupling.
Home networkA home network or home area network (HAN) is a type of computer network that facilitates communication among devices within the close vicinity of a home. Devices capable of participating in this network, for example, smart devices such as network printers and handheld mobile computers, often gain enhanced emergent capabilities through their ability to interact. These additional capabilities can be used to increase the quality of life inside the home in a variety of ways, such as automation of repetitive tasks, increased personal productivity, enhanced home security, and easier access to entertainment.
Cyber spyingCyber spying, cyber espionage, or cyber-collection is the act or practice of obtaining secrets and information without the permission and knowledge of the holder of the information using methods on the Internet, networks or individual computers through the use of proxy servers, cracking techniques and malicious software including Trojan horses and spyware. Cyber espionage can be used to target various actors- individuals, competitors, rivals, groups, governments, and others- in order to obtain personal, economic, political or military advantages.
