Lex-Partitioning: A New Option for BDD Search

For the exploration of large state spaces, symbolic search using binary decision diagrams (BDDs) can save huge amounts of memory and computation time. State sets are represented and modified by accessing and manipulating their characteristic functions. BDD partitioning is used to compute the image as the disjunction of smaller subimages. In this paper, we propose a novel BDD partitioning option. The partitioning is lexicographical in the binary representation of the states contained in the set that is represented by a BDD and uniform with respect to the number of states represented. The motivation of controlling the state set sizes in the partitioning is to eventually bridge the gap between explicit and symbolic search. Let n be the size of the binary state vector. We propose an O(n) ranking and unranking scheme that supports negated edges and operates on top of precomputed satcount values. For the uniform split of a BDD, we then use unranking to provide paths along which we partition the BDDs. In a shared BDD representation the efforts are O(n). The algorithms are fully integrated in the CUDD library and evaluated in strongly solving general game playing benchmarks.Comment: In Proceedings GRAPHITE 2012, arXiv:1210.611

Representation of Knowledge for Chess Endgames Towards a Self-Improving System

This thesis describes an investigation of the problems involved in representing knowledge within the task area of elementary Chess endgames. Two major criteria are taken for the choice of a model of & the chessplayer's knowledge : firstly, that algorithms constructed using the model should be natural from the viewpoint of a chessplayer and commensurate with his, view of the complexity of the task, and secondly that the algorithms should be capable of refinement in the light of experience in a manner which preserves the previous property. Elementary chess endgames are studied as a field in which programs based on tree-searching and traditional evaluation functions have achieved poor results and where tree-searching seems to play little or no part for people. It is therefore possible to examine problems of knowledge representation and program refinement largely independently of the tree-searching paradigm. A long term aim of the research is to develop a representation suitable as the basis for a fully automatic system of algorithm refinement, whilst maintaining the criteria given above. A model is proposed and algorithms are given for two endgames, King and Rook against King (KRK) and King and Pawn against King (KPK) using this model. It is argued that both algorithms are reasonably natural and compact representations and experiments in refining these algorithms are described in detail. In both cases, the process of refinement is shown to be a reasonably straightforward one (for people) and one which maintains the properties of naturalness and compactness. The possibility of automating this process is considered

The role of structured induction in expert systems

A "structured induction" technique was developed and tested using a rules- from -examples generator together with a chess -specific application package. A drawback of past experience with computer induction, reviewed in this thesis, has been the generation of machine -oriented rules opaque to the user. By use of the structured approach humanly understandable rules were synthesized from expert supplied examples. These rules correctly performed chess endgame classifications of sufficient complexity to be regarded as difficult by international master standard players. Using the "Interactive ID3" induction tools developed by the author, chess experts, with a little programming support, were able to generate rules which solve problems considered difficult or impossible by conventional programming techniques. Structured induction and associated programming tools were evaluated using the chess endgames Icing and Pawn vs. King (Black -tomove) and King and Pawn vs. King and Rook (White -to -move, White Pawn on a7) as trial problems of measurable complexity.Structured solutions to both trial problems are presented, and implications of this work for the design of expert systems languages are assessed

Intellectual Property Rights in China: The Changing Politcal Economy of Chinese-American Interests

We review the evolution of modern Chinese intellectual property right (IPR) laws and enforcement and explore economic and political forces involved in international conflicts over Chinese IPR protection. Our analysis considers why the U.S. and China moved from conflict to cooperation over intellectual property rights. Structural and institutional aspects of the political economy of IPRs within each country are considered, and data on Chinese-U.S. trade in intellectual property-intensive goods are examined. We conclude that although enforcement of IPRs within China continues to be relatively weak, Chinese IPR institutions are converging on those in the OECD nations.

The dark side of the board: advances in chess Kriegspiel

While imperfect information games are an excellent model of real-world problems and tasks, they are often difficult for computer programs to play at a high level of proficiency, especially if they involve major uncertainty and a very large state space. Kriegspiel, a variant of chess making it similar to a wargame, is a perfect example: while the game was studied for decades from a game-theoretical viewpoint, it was only very recently that the first practical algorithms for playing it began to appear. This thesis presents, documents and tests a multi-sided effort towards making a strong Kriegspiel player, using heuristic searching, retrograde analysis and Monte Carlo tree search algorithms to achieve increasingly higher levels of play. The resulting program is currently the strongest computer player in the world and plays at an above-average human level

Symbolic Search in Planning and General Game Playing

Search is an important topic in many areas of AI. Search problems often result in an immense number of states. This work addresses this by using a special datastructure, BDDs, which can represent large sets of states efficiently, often saving space compared to explicit representations. The first part is concerned with an analysis of the complexity of BDDs for some search problems, resulting in lower or upper bounds on BDD sizes for these. The second part is concerned with action planning, an area where the programmer does not know in advance what the search problem will look like. This part presents symbolic algorithms for finding optimal solutions for two different settings, classical and net-benefit planning, as well as several improvements to these algorithms. The resulting planner was able to win the International Planning Competition IPC 2008. The third part is concerned with general game playing, which is similar to planning in that the programmer does not know in advance what game will be played. This work proposes algorithms for instantiating the input and solving games symbolically. For playing, a hybrid player based on UCT and the solver is presented

Using punctuation as an iconic system for describing and augmenting video structure

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2001.Includes bibliographical references (leaves 98-101).Affordable digital cameras, high bandwidth connectivity and large-scale video hosting websites are combining to offer an alternative mode of production and channel of distribution for independent filmmakers and home moviemakers. There is a growing need to develop systems that meaningfully support the desires of these filmmakers to communicate and collaborate effectively with others and to propel cinematic storytelling into new and dynamic realms. This document proposes the development of a networked software application, called PlusShorts, that will allow a distributed group of users to contribute to and collaborate upon the creation of shared movie sequences. This system introduces an iconic language, consisting of punctuation symbols, for annotating, sharing and interpreting conceptual ideas about cinematic structure. The PlusShorts application presents individual movie sequences as elements within an evolving cinematic storyspace, where participants can explore, collaborate and share ideas.Aisling Geraldine Mary Kelliher.S.M