5 research outputs found
A Dynamical Systems Approach for Static Evaluation in Go
In the paper arguments are given why the concept of static evaluation has the
potential to be a useful extension to Monte Carlo tree search. A new concept of
modeling static evaluation through a dynamical system is introduced and
strengths and weaknesses are discussed. The general suitability of this
approach is demonstrated.Comment: IEEE Transactions on Computational Intelligence and AI in Games, vol
3 (2011), no
I Am Error
I Am Error is a platform study of the Nintendo Family Computer (or Famicom), a videogame console first released in Japan in July 1983 and later exported to the rest of the world as the Nintendo Entertainment System (or NES). The book investigates the underlying computational architecture of the console and its effects on the creative works (e.g. videogames) produced for the platform. I Am Error advances the concept of platform as a shifting configuration of hardware and software that extends even beyond its ‘native’ material construction. The book provides a deep technical understanding of how the platform was programmed and engineered, from code to silicon, including the design decisions that shaped both the expressive capabilities of the machine and the perception of videogames in general. The book also considers the platform beyond the console proper, including cartridges, controllers, peripherals, packaging, marketing, licensing, and play environments. Likewise, it analyzes the NES’s extension and afterlife in emulation and hacking, birthing new genres of creative expression such as ROM hacks and tool-assisted speed runs. I Am Error considers videogames and their platforms to be important objects of cultural expression, alongside cinema, dance, painting, theater and other media. It joins the discussion taking place in similar burgeoning disciplines—code studies, game studies, computational theory—that engage digital media with critical rigor and descriptive depth. But platform studies is not simply a technical discussion—it also keeps a keen eye on the cultural, social, and economic forces that influence videogames. No platform exists in a vacuum: circuits, code, and console alike are shaped by the currents of history, politics, economics, and culture—just as those currents are shaped in kind
Bandit algorithms for searching large spaces
Bandit games consist of single-state environments in which an agent must sequentially
choose actions to take, for which rewards are given. The objective being to maximise
the cumulated reward, the agent naturally seeks to build a model of the relationship
between actions and rewards. The agent must both choose uncertain actions in order
to improve its model (exploration), and actions that are believed to yield high rewards
according to the model (exploitation). The choice of an action to take is called a play
of an arm of the bandit, and the total number of plays may or may not be known in
advance.
Algorithms designed to handle the exploration-exploitation dilemma were initially
motivated by problems with rather small numbers of actions. But the ideas they were
based on have been extended to cases where the number of actions to choose from is
much larger than the maximum possible number of plays. Several problems fall into this
setting, such as information retrieval with relevance feedback, where the system must
learn what a user is looking for while serving relevant documents often enough, but
also global optimisation, where the search for an optimum is done by selecting where
to acquire potentially expensive samples of a target function. All have in common the
search of large spaces.
In this thesis, we focus on an algorithm based on the Gaussian Processes probabilistic
model, often used in Bayesian optimisation, and the Upper Confidence Bound
action-selection heuristic that is popular in bandit algorithms. In addition to demonstrating
the advantages of the GP-UCB algorithm on an image retrieval problem, we
show how it can be adapted in order to search tree-structured spaces. We provide an
efficient implementation, theoretical guarantees on the algorithm's performance, and
empirical evidence that it handles large branching factors better than previous bandit-based
algorithms, on synthetic trees
Modelling Uncertainty in the Game of Go
Go is an ancient oriental game whose complexity has defeated attempts to automate it. We suggest using probability in a Bayesian sense to model the uncertainty arising from the vast complexity of the game tree. We present a simple conditional Markov random field model for predicting the pointwise territory outcome of a game. The topology of the model reflects the spatial structure of the Go board. We describe a version of the Swendsen-Wang process for sampling from the model during learning and apply loopy belief propagation for rapid inference and prediction. The model is trained on several hundred records of professional games. Our experimental results indicate that the model successfully learns to predict territory despite its simplicity