Evolving Nash-optimal poker strategies using evolutionary computation

This paper focuses on the development of a competitive computer player for the one versus one Texas Hold’em poker using evolutionary algorithms (EA). A Texas Hold’em game engine is first constructed where an efficient odds calculator is programmed to allow for the abstraction of a player’s cards, which yield important but complex information. Effort is directed to realize an optimal player that will play close to the Nash equilibrium (NE) by proposing a new fitness criterion. Preliminary studies on a simplified version of poker highlighted the intransitivity nature of poker. The evolved player displays strategies that are logical but reveals insights that are hard to comprehend e.g., bluffing. The player is then benchmarked against Poki and PSOpti, which is the best heads-up Texas Hold’em artificial intelligence to date and plays closest to the optimal Nash equilibrium. Despite the much constrained chromosomal strategy representation, simulated results verified that evolutionary algorithms are effective in creating strategies that are comparable to Poki and PSOpti in the absence of expert knowledge.     

Evaluation approach to stock trading system using evolutionary computation

The past researches emphasize merely the avoidance of over-learning at the system level and ignore the problem of over-learning at the model level, which lead to the poor performance of the evolutionary computation based stock trading decision-making system. This study presents a new evaluation approach to focus on evaluating the generalization capability at the model level. An empirical study was provided and the results reveal four important findings. First, the decision-making system generated at the model design stage outperforms the system generated at the model validation stage, which shows over-learning at the model level. Secondly, for the decision-making system generated either at the model design stage or at the model validation stage, the investment performance in the training period is much better than that in the testing period, exhibiting over-learning at the system level. Third, employing moving timeframe approach is unable to improve the investment performance at the model validation stage. Fourth, reducing the evolution generation and input variables are unable to avoid the over-learning at the model level. The major contribution of this study is to clarify the issue of over-learning at the model and the system level. For future research, this study developed a more reliable evaluation approach in examining the generalization capability of evolutionary computation based decision-making system.     

新型模拟进化计算

提出了一种新的模拟进化计算,它模仿新宇宙进化理论中膨胀、收缩两种模式交互作用,推动宇宙进步的过程。膨胀操作提高了种群的多样性和进化算法克服局部收敛的能力,收缩操作吸取了不同群体的优良特性,改善了算法的计算效率,实验结果表明该范式是有效的。     

Customizable execution environments for evolutionary computation using BOINC + virtualization

Evolutionary algorithms (EAs) consume large amounts of computational resources, particularly when they are used to solve real-world problems that require complex fitness evaluations. Beside the lack of resources, scientists face another problem: the absence of the required expertise to adapt applications for parallel and distributed computing models. Moreover, the computing power of PCs is frequently underused at institutions, as desktops are usually devoted to administrative tasks. Therefore, the proposal in this work consists of providing a framework that allows researchers to massively deploy EA experiments by exploiting the computing power of their instituions’ PCs by setting up a Desktop Grid System based on the BOINC middleware. This paper presents a new model for running unmodified applications within BOINC with a web-based centralized management system for available resources. Thanks to this proposal, researchers can run scientific applications without modifying the application’s source code, and at the same time manage thousands of computers from a single web page. Summarizing, this model allows the creation of on-demand customized execution environments within BOINC that can be used to harness unused computational resources for complex computational experiments, such as EAs. To show the performance of this model, a real-world application of Genetic Programming was used and tested through a centrally-managed desktop grid infrastructure. Results show the feasibility of the approach that has allowed researchers to generate new solutions by means of an easy to use and manage distributed system.     

Multi-robot mission planning using evolutionary computation with incremental task addition

Intelligent Service Robotics - Mission planning asks the robot to solve complex missions, requiring the robot to execute several actions such that a complex goal condition (called mission) is...     

Radio-frequency inductor synthesis using evolutionary computation and Gaussian-process surrogate modeling

In recent years, the application of evolutionary computation techniques to electronic circuit design problems, ranging from digital to analog and radiofrequency circuits, has received increasing attention. The level of maturity runs inversely to the complexity of the design task, less complex in digital circuits, higher in analog ones and still higher in radiofrequency circuits. Radiofrequency inductors are key culprits of such complexity. Their key performance parameters are inductance and quality factors, both a function of the frequency. The inductor optimization requires knowledge of such parameters at a few representative frequencies. Most common approaches for optimization-based radiofrequency circuit design use analytical models for the inductors. Although a lot of effort has been devoted to improve the accuracy of such analytical models, errors in inductance and quality factor in the range of 5%–25% are usual and it may go as high as 200% for some device sizes. When the analytical models are used in optimization-based circuit design approaches, these errors lead to suboptimal results, or, worse, to a disastrous non-fulfilment of specifications. Expert inductor designers rely on iterative evaluations with electromagnetic simulators, which, properly configured, are able to yield a highly accurate performance evaluation. Unfortunately, electromagnetic simulations typically take from some tens of seconds to a few hours, hampering their coupling to evolutionary computation algorithms. Therefore, analytical models and electromagnetic simulation represent extreme cases of the accuracy-efficiency trade-off in performance evaluation of radiofrequency inductors. Surrogate modeling strategies arise as promising candidates to improve such trade-off. However, obtaining the necessary accuracy is not that easy as inductance and quality factor at some representative frequencies must be obtained and both performances change abruptly around the self-resonance frequency, which is particular to each device and may be located above or below the frequencies of interest. Both, offline and online training methods will be considered in this work and a new two-step strategy for inductor modeling is proposed that significantly improves the accuracy of offline methods The new strategy is demonstrated and compared for both, single-objective and multi-objective optimization scenarios. Numerous experimental results show that the proposed two-step approach outperforms simpler application strategies of surrogate modelling techniques, getting comparable performances to approaches based on electromagnetic simulation but with orders of magnitude less computational effort.     

Image segmentation using a multilayer level-set approach

We propose an efficient multilayer segmentation method based on implicit curve evolution and on variational approach. The proposed formulation uses the minimal partition problem as formulated by D. Mumford and J. Shah, and can be seen as a more efficient extension of the segmentation models previously proposed in Chan and Vese (Scale-Space Theories in Computer Vision, Lecture Notes in Computer Science, Vol. 1682, pp. 141–151, 1999, IEEE Trans Image Process 10(2):266–277, 2001), and Vese and Chan (Int J Comput Vis 50(3):271–293, 2002). The set of unknown discontinuities is represented implicitly by several nested level lines of the same function, as inspired from prior work on island dynamics for epitaxial growth (Caflisch et al. in Appl Math Lett 12(4):13, 1999; Chen et al. in J Comput Phys 167:475, 2001). We present the Euler–Lagrange equations of the proposed minimizations together with theoretical results of energy decrease, existence of minimizers and approximations. We also discuss the choice of the curve regularization and conclude with several experimental results and comparisons for piecewise-constant segmentation of gray-level and color images.     

Image segmentation using a dynamic thresholding pyramid

An image segmentation algorithm based on multi-resolution processing is presented. The algorithm is based on applying a local clustering at each level of a linked pyramid data structure allowing seed nodes to be defined. These seed nodes are the root nodes of regions at the base of the pyramid, appearing in the multi-resolution data structure at a level appropriate to the region size. By applying a merging process followed by a classification step, accurate segmentations are obtained for both natural and synthetic images without the need for a priori knowledge. Results show that the algorithm gives accurate segmentations even in low signal to noise ratios.     

Barcode design by evolutionary computation

This paper proposes a method for generating 2-dimensional barcode incorporated some illustrations inside of the code without detracting machine-readability and stored information. We formulate the task that finding appropriate positions, scales, and angles of illustrations, photographs, logos or other image items put in QR code as an optimization problem. By using evolutionary computation algorithm, the proposed system can find positions in which given image items can be merged without damaging machine-readability. QR code is trademarked by Denso Wave, inc. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Adversarial search by evolutionary computation

In this paper, we consider the problem of finding good next moves in two-player games. Traditional search algorithms, such as minimax and alpha-beta pruning, suffer great temporal and spatial expansion when exploring deeply into search trees to find better next moves. The evolution of genetic algorithms with the ability to find global or near global optima in limited time seems promising, but they are inept at finding compound optima, such as the minimax in a game-search tree. We thus propose a new genetic algorithm-based approach that can find a good next move by reserving the board evaluation values of new offspring in a partial game-search tree. Experiments show that solution accuracy and search speed are greatly improved by our algorithm.     

网格计算及其在进化计算中的应用

提出了一种将网格技术应用于进化算法的计算模式。这种计算模式使用规则与规则集共同演变的模式,实现了数据挖掘技术中的分类。它利用网格计算技术的优势,提高了以往复杂的数据挖掘技术的能力和效率。     

Redundant representations in evolutionary computation

This paper discusses how the use of redundant representations influences the performance of genetic and evolutionary algorithms. Representations are redundant if the number of genotypes exceeds the number of phenotypes. A distinction is made between synonymously and non-synonymously redundant representations. Representations are synonymously redundant if the genotypes that represent the same phenotype are very similar to each other. Non-synonymously redundant representations do not allow genetic operators to work properly and result in a lower performance of evolutionary search. When using synonymously redundant representations, the performance of selectorecombinative genetic algorithms (GAs) depends on the modification of the initial supply. We have developed theoretical models for synonymously redundant representations that show the necessary population size to solve a problem and the number of generations goes with O(2(kr)/r), where kr is the order of redundancy and r is the number of genotypic building blocks (BB) that represent the optimal phenotypic BB. As a result, uniformly redundant representations do not change the behavior of GAs. Only by increasing r, which means overrepresenting the optimal solution, does GA performance increase. Therefore, non-uniformly redundant representations can only be used advantageously if a-priori information exists regarding the optimal solution. The validity of the proposed theoretical concepts is illustrated for the binary trivial voting mapping and the real-valued link-biased encoding. Our empirical investigations show that the developed population sizing and time to convergence models allow an accurate prediction of the empirical results.     

交互式进化计算研究进展

针对交互式进化计算的研究进展进行综述.首先对其求解模式及特点进行描述;然后对其理论、应用与改进研究进行系统分析,并深入讨论了交互式进化计算中的不确定性;最后指出了今后需要进一步研究的问题.     

Image segmentation using optimal and hierarchical piecewise-constant approximations

The problem of approaching optimal image approximations using quasi-optimal hierarchical approximations, which are close to the optimal ones in terms of the total squared error, is considered. The problem is solved using algorithms for merging and dividing pixel clusters. The algorithms are based on elementary formulas. Information encoded in the image is proposed to be described, based on quasi-optimal approximations, using the invariant isomorphic image representation. The definition of the integer quantity of information is given, and the comparison of the integer estimate with the classical estimates in terms of R. Hartley and K. Shannon is performed. The experimental study of the properties of quasi-optimal hierarchical approximations, which are characteristic and uncharacteristic of nonhierarchical optimal image approximations, is carried out.     

Image segmentation using a local extrema texture measure

An image segmentation technique is proposed which uses a texture measure that counts the number of local extrema in a window centered at each picture point. Four gray level pictures are derived, each of which represents a texture or gray level property of the original image. These intermediate pictures are used to derive the number of segments in which to divide the original image. The segmentation is then performed by assigning each pixel in the original image to a region by using a four-dimensional distance measure on the intermediate pictures, comparing each location to each selected segment. This process is then repeated in a hierarchical structure using decreasing window sizes so that smaller regions within the larger ones are defined. The computations required are amenable to real-time video implementation using state-of-the-art devices.     

迭代分水岭和脊检测的图像分割

对具有边界不明显和亮度非均匀特征的图像,如金相学图像,使用传统方法进行分割难以得到令人满意的分割效果.因此,提出了一种新的图像分割算法--基于迭代过程的分水岭改进算法.该算法运用脊来限定区域生长的范围,采用双阈值方法选择种子,而脊叠加为分水岭算法中的最高吃水线.为了解决过分割的问题,利用贝叶斯分类规则反复地进行区域块的合并.实验结果表明,在无需调整太多参数的情况下,该算法可以有效地实现图像分割.     

基于克隆选择遗传算法的图像阈值分割

为了快速有效地得到图像的最佳阈值,基于人工免疫系统中的克隆选择原理,提出一种新的混合遗传算法,并将其应用于基于最大类间方差法的图像阈值分割问题.该算法用克隆选择代替标准遗传算法中的概率选择,根据抗体.抗原的亲和度对种群中的优良个体有选择的克隆增殖,并利用抗体浓度调节机制采抑制高浓度抗体、促进低浓度抗体,以保持种群中个体的多样性.从而避免了遗传算法陷入局部最优解,出现早熟收敛现象.仿真实验结果表明,该算法对多类图像的良好分割效果和较强的实用能力.