幻影围棋博弈策略

1
INTRODUCTION
Recent years, the technique of computer game has been fully developed. Such as Go, Poker, Chess and so on. Phantom Go is an enjoyable game with hidden information [1]. Its syntaxes is same with game of Go, when most stones have been detected [2]. Go is a completed information game, while Phantom Go is an uncompleted information game, which means one player do not know the opponent’s board, only to guess the moves of opponent. It seems increase the degree of difficulty. A two-person information symmetrical game such as Go, NoGo and Phantom Go can be represented by a structure of tree, and finding the near optimal solutions are usually dealt with by searching its tree [3]. MC (Monte Carlo) and UCT (Upper bound Confidence for Tee) are mainly algorithms for searching tree used in Go and some other games. Practices have shown that the two algorithms are very effective in Go. The Phantom Go game lacks enough information, and each stones’ value is same for all situations, which make it difficult to define the feature value for evaluation of position. Another problem is that the searching space is huge and complex, which make it difficult to select a static evaluation to create an effective move. Lastly, the traditional methods are not to apply to Phantom Go directly. This article is structured as follows. Section 2 introduces an overview of research related to Phantom Go. Section 3 describes the main three algorithms including MC method, UCT method, and Specify Gambit. Section 4 shows the experiments and analysis. Finally, section 5 gives the summary of this article.
3
ALGORITHM AND STRATEGY
2
PHANTOM GO
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3.1 Monte Carlo
Monte Carlo method is a stochastic simulation method based on probability and statistics theory. It will solve problems with certain probability model associated with statistical simulation, implementation or sampling by computer, in order to obtain approximate solutions of the problem. Many kinds of computer games have used this method, like Poker [5], Bridge [6] and Go [7]. In Go, the idea is to occupy a position in the board, then select the points randomly in all area without stones until all the positions are occupied except positions of eyes [8]. At last, both the number of stones will be calculated respectively which is one of the evaluation methods of the move. In order to get a good
This work is supported by Innovative Training Program of Shenyang Aerospace University (No.2012093).
Game of Go is complete information game with two players, Black and White, playing stones on the board in alternating turns. The board is a rectangular grid and players place stones on the intersections of the board. The goal of the game is to occupy or encircle more territory [4]. Whereas Phantom Go is incomplete information game with two players and one referee. It usually played on 9x9 boards which is same with Go but smaller than Go board. There are three boards, one for each player and one for
Fig.1 two boards(the left is reference board; the right is Black board) Phantom Go originated in Europe, and developed in China recently. In 2011, the project of Phantom Go was added to National Collage Computer Game Competition. To the year of 2013, this project has been held three times. More and more college students interested in the game of Phantom Go.The number of player involved in the Phantom Go game has been increasing, and their levels have been enhanced largely.
arbiter. The board of the arbiter is called the reference board. Each player only knows the position of the stones he has placed, and the opponent stones’ location is unknown to him. The referee can see all the boards. When a player places a stone, the referee will tell him or her whether the move is legal or illegal according to the reference board. The referee will announce the winner according to the size of occupied territory in a round. For instance, the fig.1 depicts a reference board and a player’s board after 30 moves.
Study of Strategy Selection Based on Phantom Go
LiFei1, Ouyang Li1,2, Wang Yanjie1, Dong Yanqiu1
1. Engineering Training Center, Shenyang Aerospace University, Shenyang, 110136, China E-mail: alinafeili@ 2. Safety Engineering Institute, Shenyang Aerospace University, Shenyang, 110136, China E-mail: ouyangli729@ Abstract: Recent years, Monte Carlo and UCT (Upper bound Confidence for Tree) have been widely used in algorithms of computer games, and considerably improved computer Go programs. Phantom Go is a game with incomplete information and different with Go. The study of Phantom Go is just beginning. Most algorithms of Phantom Go applying Monte Carlo or UCT directly, but results are not quite satisfactory. In this paper, we analysis the characteristic of Phantom go, apply several strategies in different stages and try to improve the competition of program. Our experimental findings indicate that strategies selection method can be applied to Phantom Go effectively. Key Words: Computer Game，Phantom Go, Monte Carlo，UCT，Strategy Selection