Horizon Effect
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Horizon Effect
The horizon effect, also known as the horizon problem, is a problem in artificial intelligence whereby, in many games, the number of possible states or positions is immense and computers can only feasibly search a small portion of them, typically a few plies down the game tree. Thus, for a computer searching only five plies, there is a possibility that it will make a detrimental move, but the effect is not visible because the computer does not search to the depth of the error (''i.e.'', beyond its "horizon"). When evaluating a large game tree using techniques such as minimax with alpha-beta pruning, search depth is limited for feasibility reasons. However, evaluating a partial tree may give a misleading result. When a significant change exists just over the horizon of the search depth, the computational device falls victim to the horizon effect. In 1973 Hans Berliner named this phenomenon, which he and other researchers had observed, the "Horizon Effect." He split the effect in ...
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Artificial Intelligence
Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machines, as opposed to intelligence displayed by animals and humans. Example tasks in which this is done include speech recognition, computer vision, translation between (natural) languages, as well as other mappings of inputs. The ''Oxford English Dictionary'' of Oxford University Press defines artificial intelligence as: the theory and development of computer systems able to perform tasks that normally require human intelligence, such as visual perception, speech recognition, decision-making, and translation between languages. AI applications include advanced web search engines (e.g., Google), recommendation systems (used by YouTube, Amazon and Netflix), understanding human speech (such as Siri and Alexa), self-driving cars (e.g., Tesla), automated decision-making and competing at the highest level in strategic game systems (such as chess and Go). ...
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Ply (game Theory)
Ply, Pli, Plies or Plying may refer to: Common uses * Ply (layer), typically of paper or wood ** Plywood, made of layers of wood ** Tire ply, a layer of cords embedded in the rubber of a tire Places * Plymouth railway station, England, station code PLY *Plymouth Municipal Airport (Indiana), IATA airport code PLY People * Plies (rapper), American rapper Arts, entertainment, and media * Ply (game theory), a turn in game play * PLY (postnominal), a postnominal for athletes that participate in the Paralympic Games Computing and technology * PLY (file format) or Polygon File Format * PLY (Python Lex-Yacc), a parsing tool for Python * Plying In the textile arts, plying (from the French verb ''plier'', "to fold", from the Latin verb ''plico'', from the ancient Greek verb .) is a process of twisting one or more strings (called strands) of yarn together to create a stronger yarn. Strands ...
, a spinning technique to make yarn {{disambig ...
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Game Tree
In the context of Combinatorial game theory, which typically studies sequential games with perfect information, a game tree is a graph representing all possible game states within such a game. Such games include well-known ones such as chess, checkers, Go, and tic-tac-toe. This can be used to measure the complexity of a game, as it represents all the possible ways a game can pan out. Due to the large game trees of complex games such as chess, algorithms that are designed to play this class of games will use partial game trees, which makes computation feasible on modern computers. Various methods exist to solve game trees. If a complete game tree can be generated, a deterministic algorithm, such as backward induction or retrograde analysis can be used. Randomized algorithms and minimax algorithms such as MCTS can be used in cases where a complete game tree is not feasible. Understanding the game tree To better understand the game tree, it can be thought of as a technique for an ...
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Minimax
Minimax (sometimes MinMax, MM or saddle point) is a decision rule used in artificial intelligence, decision theory, game theory, statistics, and philosophy for ''mini''mizing the possible loss for a worst case (''max''imum loss) scenario. When dealing with gains, it is referred to as "maximin" – to maximize the minimum gain. Originally formulated for several-player zero-sum game theory, covering both the cases where players take alternate moves and those where they make simultaneous moves, it has also been extended to more complex games and to general decision-making in the presence of uncertainty. Game theory In general games The maximin value is the highest value that the player can be sure to get without knowing the actions of the other players; equivalently, it is the lowest value the other players can force the player to receive when they know the player's action. Its formal definition is: :\underline = \max_ \min_ Where: * is the index of the player of interest. ...
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Alpha-beta Pruning
Alphabeta is an Israeli musical group. Alphabeta or Alpha Beta may also refer to: *The Greek alphabet, from ''Alpha'' (Αα) and ''Beta'' (Ββ), the first two letters *Alpha Beta, a former chain of Californian supermarkets *Alpha and beta anomers (chemistry) *Alpha–beta pruning, a type of search algorithm *Alpha-beta transformation, a mathematical transformation in electrical engineering *Alpha-beta unsaturated carbonyl compounds, a class of organic compounds *Alpha beta filter, a predictive filter *Alpha (finance) and Beta (finance), two measures characterizing the return of an investment portfolio *The Alpha Betas, a fraternity in the ''Revenge of the Nerds'' film series *''Alpha Betas,'' an animated webseries created by Chris Bruno and David Howard Lee starring Evan Fong Evan Fong (born 31 May 1992), known online as VanossGaming (or simply Vanoss), is a Canadian internet personality, video game commentator, music producer, and DJ. He posts montage-style videos on YouTube ...
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Hans Berliner
Hans Jack Berliner (January 27, 1929 – January 13, 2017) was a Professor of Computer Science at Carnegie Mellon University, and was the World Correspondence Chess Champion, from 1965–1968. He was a Grandmaster of Correspondence Chess. He directed the construction of the chess computer HiTech, and was also a published chess writer. Early life Berliner was born January 27, 1929 in Berlin to a Jewish family. One of his classmates at school was future Estonian President Lennart Meri, whose father was serving as Estonia's ambassador to Germany. In 1937, Berliner's family moved to the United States to escape Nazi persecution, taking up residence in Washington, D.C. He learned chess at age 13, and "it quickly became his main preoccupation." Berliner is mentioned in "How I Started To Write", an essay by Carlos Fuentes, where he is described as "an extremely brilliant boy", with "a brilliant mathematical mind". "I shall always remember his face, dark and trembling, his aquiline ...
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Greedy Algorithm
A greedy algorithm is any algorithm that follows the problem-solving heuristic of making the locally optimal choice at each stage. In many problems, a greedy strategy does not produce an optimal solution, but a greedy heuristic can yield locally optimal solutions that approximate a globally optimal solution in a reasonable amount of time. For example, a greedy strategy for the travelling salesman problem (which is of high computational complexity) is the following heuristic: "At each step of the journey, visit the nearest unvisited city." This heuristic does not intend to find the best solution, but it terminates in a reasonable number of steps; finding an optimal solution to such a complex problem typically requires unreasonably many steps. In mathematical optimization, greedy algorithms optimally solve combinatorial problems having the properties of matroids and give constant-factor approximations to optimization problems with the submodular structure. Specifics Greedy algorith ...
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Quiescence Search
Quiescence search is an algorithm typically used to extend search at unstable nodes in minimax game trees in game-playing computer programs. It is an extension of the evaluation function to defer evaluation until the position is stable enough to be evaluated statically, that is, without considering the history of the position or future moves from the position. It mitigates the effect of the horizon problem faced by AI engines for various games like chess and Go. Human players usually have enough intuition to decide whether to abandon a bad-looking move, or search a promising move to a great depth. A quiescence search attempts to emulate this behavior by instructing a computer to search "volatile" positions to a greater depth than "quiet" ones to make sure there are no hidden traps and to get a better estimate of its value. Any sensible criterion may be used to distinguish "quiet" positions from "volatile" positions. One common criterion is that moves exist in the position tha ...
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Capture (chess)
This glossary of chess explains commonly used terms in chess, in alphabetical order. Some of these terms have their own pages, like ''fork'' and ''pin''. For a list of unorthodox chess pieces, see Fairy chess piece; for a list of terms specific to chess problems, see Glossary of chess problems; for a list of named opening lines, see List of chess openings; for a list of chess-related games, see List of chess variants. A B , "lightning"] A #fast chess, fast form of chess with a very short time limit, usually three or five minutes per player for the entire game. With the advent of electronic chess clocks, the time remaining is often incremented by one or two seconds per move.Schiller 2003, p. 398 C ...
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Chess
Chess is a board game for two players, called White and Black, each controlling an army of chess pieces in their color, with the objective to checkmate the opponent's king. It is sometimes called international chess or Western chess to distinguish it from related games, such as xiangqi (Chinese chess) and shogi (Japanese chess). The recorded history of chess goes back at least to the emergence of a similar game, chaturanga, in seventh-century India. The rules of chess as we know them today emerged in Europe at the end of the 15th century, with standardization and universal acceptance by the end of the 19th century. Today, chess is one of the world's most popular games, played by millions of people worldwide. Chess is an abstract strategy game that involves no hidden information and no use of dice or cards. It is played on a chessboard with 64 squares arranged in an eight-by-eight grid. At the start, each player controls sixteen pieces: one king, one queen, two rooks, t ...
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Leaf Node
In computer science, a tree is a widely used abstract data type that represents a hierarchical tree structure with a set of connected nodes. Each node in the tree can be connected to many children (depending on the type of tree), but must be connected to exactly one parent, except for the ''root'' node, which has no parent. These constraints mean there are no cycles or "loops" (no node can be its own ancestor), and also that each child can be treated like the root node of its own subtree, making recursion a useful technique for tree traversal. In contrast to linear data structures, many trees cannot be represented by relationships between neighboring nodes in a single straight line. Binary trees are a commonly used type, which constrain the number of children for each parent to exactly two. When the order of the children is specified, this data structure corresponds to an ordered tree in graph theory. A value or pointer to other data may be associated with every node in the tree ...
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Sacrifice (chess)
In chess, a sacrifice is a move that gives up a piece with the objective of gaining tactical or positional compensation in other forms. A sacrifice could also be a deliberate exchange of a chess piece of higher value for an opponent's piece of lower value. Any chess piece except the king may be sacrificed. Because players usually try to hold on to their own pieces, offering a sacrifice can come as an unpleasant surprise to one's opponent, putting them off balance and causing them to waste precious time trying to calculate whether the sacrifice is sound or not, and whether to accept it. Sacrificing one's queen (the most valuable piece), or a string of pieces, adds to the surprise, and such games can be awarded . Types of sacrifice Real versus sham Rudolf Spielmann proposed a division between sham and real sacrifices: * In a ''real sacrifice'', the sacrificing player will often have to play on with less than their opponent for quite some time. * In a ''sham sacrifice'', t ...
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