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Learning Decision Rules from Data Streams

AAAI Conferences

However, it has been shown that the antecedents of individual rules Decision rules, which can provide good interpretability may contain irrelevant conditions. C4.5rules (Quinlan, 1993) and flexibility for data mining tasks, uses an optimization procedure to simplify conditions. The have received very little attention in the stream optimization is done in two phases. First, each rule is generalized mining community so far. In this work we introduce by deleting conditions that do not seem to be helpful a new algorithm to learn rule sets, designed in discriminating the classes. A greedy search method is for open-ended data streams.


Constituent Grammatical Evolution

AAAI Conferences

We present Constituent Grammatical Evolution (CGE), a new evolutionary automatic programming algorithm that extends the standard Grammatical Evolution algorithm by incorporating the concepts of constituent genes and conditional behaviour-switching. CGE builds from elementary and more complex building blocks a control program which dictates the behaviour of an agent and it is applicable to the class of problems where the subject of search is the behaviour of an agent in a given environment. It takes advantage of the powerful Grammatical Evolution feature of using a BNF grammar definition as a plug-in component to describe the output language to be produced by the system. The main benchmark problem in which CGE is evaluated is the Santa Fe Trail problem using a BNF grammar definition which defines a search space semantically equivalent with that of the original definition of the problem by Koza. Furthermore, CGE is evaluated on two additional problems, the Los Altos Hills and the Hampton Court Maze. The experimental results demonstrate that Constituent Grammatical Evolution outperforms the standard Grammatical Evolution algorithm in these problems, in terms of both efficiency (percent of solutions found) and effectiveness (number of required steps of solutions found).


Generative Structure Learning for Markov Logic Networks Based on Graph of Predicates

AAAI Conferences

In this paper we present a new algorithm for generatively learning the structure of Markov Logic Networks. This algorithm relies on a graph of predicates, which summarizes the links existing between predicates and on relational information between ground atoms in the training database. Candidate clauses are produced by means of a heuristical variabilization technique. According to our first experiments, this approach appears to be promising.


Flexible, High Performance Convolutional Neural Networks for Image Classification

AAAI Conferences

We present a fast, fully parameterizable GPU implementation of Convolutional Neural Network variants. Our feature extractors are neither carefully designed nor pre-wired, but rather learned in a supervised way. Our deep hierarchical architectures achieve the best published results on benchmarks for object classification (NORB, CIFAR10) and handwritten digit recognition (MNIST), with error rates of 2.53%, 19.51%, 0.35%, respectively. Deep nets trained by simple back-propagation perform better than more shallow ones. Learning is surprisingly rapid. NORB is completely trained within five epochs. Test error rates on MNIST drop to 2.42%, 0.97% and 0.48% after 1, 3 and 17 epochs, respectively.


Increasing the Scalability of the Fitting of Generalised Block Models for Social Networks

AAAI Conferences

In recent years, the summarisation and decomposition of social networks has become increasingly popular, from community finding to role equivalence. However, these approaches concentrate on one type of model only. Generalised block modelling decomposes a network into independent, interpretable, labeled blocks, where the block labels summarise the relationship between two sets of users. Existing algorithms for fitting generalised block models do not scale beyond networks of 100 vertices. In this paper, we introduce two new algorithms, one based on genetic algorithms and the other on simulated annealing, that is at least two orders of magnitude faster than existing algorithms and obtaining similar accuracy. Using synthetic and real datasets, we demonstrate their efficiency and accuracy and show how generalised block modelling and our new approaches enable tractable network summarisation and modelling of medium sized networks.


Using Cases as Heuristics in Reinforcement Learning: A Transfer Learning Application

AAAI Conferences

Another way to speed up a RL algorithm is by using Transfer Learning, a paradigm of machine learning that In this paper we propose to combine three AI techniques reuses knowledge accumulated in a previous task to speed up to speed up a Reinforcement Learning algorithm the learning of a novel, but related, target task [Taylor and in a Transfer Learning problem: Casebased Stone, 2009]. Reasoning, Heuristically Accelerated Reinforcement This paper investigates the use of the Case-Based Heuristically Learning and Neural Networks. To do Accelerated Reinforcement Learning (CB-HARL) algorithm so, we propose a new algorithm, called L3, which [Bianchi et al., 2009] as a means to transfer learning works in 3 stages: in the first stage, it uses Reinforcement acquired by one agent during its training in one problem to Learning to learn how to perform one another agent that has to learn how to solve a similar, but task, and stores the optimal policy for this problem more complex, problem. To do so, we propose a new algorithm, as a case-base; in the second stage, it uses a Neural called L3, which works in 3 stages: in the first stage, Network to map actions from one domain to actions it uses the Q-learning algorithm [Watkins, 1989] to learn how in the other domain and; in the third stage, it uses to perform one task, and stores the optimal policy for this the case-base learned in the first stage as heuristics problem as a case-base; in the second stage, it uses a Neural to speed up the learning performance in a related, Network to map actions from one domain to actions in but different, task. The RL algorithm used the other domain and; in the third stage, it uses the case-base in the first phase is the Q-learning and in the third learned in the first stage as heuristics in the CB-HARL algorithm, phase is the recently proposed Case-based Heuristically speeding up the learning process.


Semi-Supervised Learning from a Translation Model Between Data Distributions

AAAI Conferences

In this paper, we introduce a probabilistic classification model to address the task of semi-supervised learning. The major novelty of our proposal stems from measuring distributional relationships between the labeled and unlabeled data. This is achieved from a stochastic translation model between data distributions that is estimated from a mixture model. The proposed classifier is defined from the combination of both the translation model and a kernel logistic regression on labeled data. Experimental results obtained over synthetic and real-world data sets validate the usefulness of our proposal.


Multi-Evidence Lifted Message Passing, with Application to PageRank and the Kalman Filter

AAAI Conferences

Lifted message passing algorithms exploit repeated structure within a given graphical model to answer queries efficiently. Given evidence, they construct a lifted network of supernodes and superpotentials corresponding to sets of nodes and potentials that are indistinguishable given the evidence. Recently, efficient algorithms were presented for updating the structure of an existing lifted network with incremental changes to the evidence. In the inference stage, however, current algorithms need to construct a separate lifted network for each evidence case and run a modified message passing algorithm on each lifted network separately. Consequently, symmetries across the inference tasks are not exploited. In this paper, we present a novel lifted message passing technique that exploits symmetries across multiple evidence cases. The benefits of this multi-evidence lifted inference are shown for several important AI tasks such as computing personalized PageRanks and Kalman filters via multi-evidence lifted Gaussian belief propagation.


A Competitive Strategy for Function Approximation in Q-Learning

AAAI Conferences

In this work we propose an approach for generalization in continuous domain Reinforcement Learning that, instead of using a single function approximator, tries many different function approximators in parallel, each one defined in a different region of the domain. Associated with each approximator is a relevance function that locally quantifies the quality of its approximation, so that, at each input point, the approximator with highest relevance can be selected. The relevance function is defined using parametric estimations of the variance of the q-values and the density of samples in the input space, which are used to quantify the accuracy and the confidence in the approximation, respectively. These parametric estimations are obtained from a probability density distribution represented as a Gaussian Mixture Model embedded in the input-output space of each approximator. In our experiments, the proposed approach required a lesser number of experiences for learning and produced more stable convergence profiles than when using a single function approximator.


On Qualitative Route Descriptions: Representation and Computational Complexity

AAAI Conferences

The generation of route descriptions is a fundamental task of navigation systems. A particular problem in this context is to identify routes that can easily be described and processed by users. In this work, we present a framework for representing route networks with the qualitative information necessary to evaluate and optimize route descriptions with regard to ambiguities in them. We identify different agent models that differ in how agents are assumed to process route descriptions while navigating through route networks. Further, we analyze the computational complexity of matching route descriptions and paths in route networks in dependency of the agent model. Finally we empirically evaluate the influence of the agent model on the optimization and the processing of route instructions.