Genetic Programming And Multi-agent Layered Learning By Reinforcements
We present an adaptation of the standard genetic program (GP) to hierarchically decomposable, multi-agent learning problems. To break down a problem that requires cooperation of multiple agents, we use the team objective function to derive a simpler, intermediate objective function for pairs of cooperating agents. We apply GP to optimize first for the intermediate, then for the team objective function, using the final population from the earlier GP as the initial seed population for the next. This layered learning approach facilitates the discovery of primitive behaviors that can be reused and adapted towards complex objectives based on a shared team goal. We use this method to evolve agents to play a subproblem of robotic soccer (keep-away soccer). Finally, we show how layered learning GP evolves better agents than standard GP, including GP with automatically defined functions, and how the problem decomposition results in a significant learning-speed increase.

title: Relational Graphical Models of Computational Workflows for Data Mining
abstract: Collaborative recommendation is the problem of analyzing the content of an information retrieval system and actions of its users, to predict additional topics or products a new user may find useful. Developing this capability poses several challenges to machine learning and reasoning under uncertainty. Recent systems such as CiteSeer  have succeeded in providing some specialized but comprehensive indices of full documents, but the kind of probabilistic models used in such indexing do not extend easily to information Grid databases and computational Grid workflows. The collection of user data from Grid portals [4] provides a test bed for the underlying IR technology, including learning and inference systems. To model workflows created using the TAVERNA editor  and SCUFL description language, the DESCRIBER system, shown in Figure 1, applies score-based structure learning algorithms, including Bayesian model selection and greedy search (cf. the K2 algorithm) adapted to relational graphical models. Figure 2 illustrates how the decision support front-end of DESCRIBER interacts with modules that learn and reason using probabilistic relational models,. The purpose is to discover interrelationships among, and thereby recommend, components used in workflows developed by other Grid users.

title: Probabilistic Prediction of Protein Secondary Structure Using Causal Networks (Extended Abstract)
abstract: In this paper we present a probabilistic approach to analysis and prediction of protein structure. We argue that this approach provides a flexible and convenient mechanism to perform general scientific data analysis in molecular biology. We apply our approach to an important problem in molecular biology--predicting the secondary structure of proteins--and obtain experimental results comparable to several other methods. The causal networks that we use provide a very convenient medium for the scientist to experiment with different empirical models and obtain possibly important insights about the problem being studied.

title: Genetic wrappers for feature selection in decision tree induction and variable ordering in Bayesian network structure learning
abstract: In this paper, we address the automated tuning of input specification for supervised inductive learning and develop combinatorial optimization solutions for two such tuning problems. First, we present a framework for selection and reordering of input variables to reduce generalization error in classification and probabilistic inference. One purpose of selection is to control overfitting using validation set accuracy as a criterion for relevance. Similarly, some inductive learning algorithms, such as greedy algorithms for learning probabilistic networks, are sensitive to the evaluation order of variables. We design a generic fitness function for validation of input specification, then use it to develop two genetic algorithm wrappers: one for the variable selection problem for decision tree inducers and one for the variable ordering problem for Bayesian network structure learning. We evaluate the wrappers, using real-world data for the selection wrapper and synthetic data for both, and discuss their limitations and generalizability to other inducers.

title: Text Extraction from the Web via Text-to-Tag Ratio
abstract: We describe a method to extract content text from diverse Web pages by using the HTML document's text-to-tag ratio rather than specific HTML cues that may not be constant across various Web pages. We describe how to compute the text-to-tag ratio on a line-by-line basis and then cluster the results into content and non-content areas. With this approach we then show surprisingly high levels of recall for all levels of precision, and a large space savings.

title: Evolutionary tree genetic programming
abstract: We introduce a clustering-based method of subpopulation management in genetic programming (GP) called Evolutionary Tree Genetic Programming (ETGP). The biological motivation behind this work is the observation that the natural evolution follows a tree-like phylogenetic pattern. Our goal is to simulate similar behavior in artificial evolutionary systems such as GP. To test our model we use three common GP benchmarks: the Ant Algorithm, 11-Multiplexer, and Parity problems.The performance of the ETGP system is empirically compared to those of the GP system. Code size and variance are consistently reduced by a small but statistically significant percentage, resulting in a slight speedup in the Ant and 11-Multiplexer problems, while the same comparisons on the Parity problem are inconclusive.

title: Parameter significance estimation and financial prediction
abstract: This paper deals with the problem of parameter significance estimation, and its application to currency exchange rate prediction. The basic problem is that over the years, practitioners in the field of financial engineering have developed dozens of technical and fundamental indicators on the basis of which they try to predict financial time series. The practitioners are now faced with the problem of finding out which combinations of those indicators are most significant or relevant, and how their significance changes over time. The authors propose a novel neural architecture calledSupNet for estimating the significance of various parameters. The methodology is based on the principle of penalizing those features that are the largest contributors to the error term. Two algorithms based on this principle are proposed. This approach is different from related methodologies, which are based on the principle of removing parameters with the least significance. The proposed methodology is demonstrated on the next day returns of the DM-US currency exchange rate, and promising results are obtained.