Asia
The Fourth International Workshop on Artificial Intelligence in Economics and Management
Y. Reich (Tel-Aviv University) proposed The paper by M. Benaroch (Syracuse University) suggested the use of knowledge-based tools for mass customization of service products; it dealt in general Grundstein (Framatome, France) reported than the other methods. At the macroeconomic and J. Zahavi (both of Tel-Aviv University) level, Deinichenko et al. presented found that genetic algorithms an expert system that utilizes performed even better than a fuzzy knowledge to analyze economic on Artificial Intelligence linear programming model on their Thus, their conclusion was Academy of Sciences) and T. Szapiro (AIEM4) was held in Tel-Aviv, that AI techniques might provide (Warsaw School of Economics) noted Israel, from 8 to 10 January 1996, better results than rigid analytic the lack of models appropriate to the with participants from 13 countries. Service to customers in the financial for discerning patterns in the economic As a matter of course, almost every area was another focus of the and demographic data of developing presentation at the workshop workshop. Lange et al. described a economies. The paper by touched on AI techniques in one way system for customizing investment Edmonds and S. Moss (Manchester or another.
RoboCup: A Challenge Problem for AI
Kitano, Hiroaki, Asada, Minoru, Kuniyoshi, Yasuo, Noda, Itsuki, Osawa, Eiichi, Matsubara, Hitoshi
The Robot World-Cup Soccer (RoboCup) is an attempt to foster AI and intelligent robotics research by providing a standard problem where a wide range of technologies can be integrated and examined. The first RoboCup competition will be held at the Fifteenth International Joint Conference on Artificial Intelligence in Nagoya, Japan. A robot team must actually perform a soccer game, incorporating various technologies, including design principles of autonomous agents, multiagent collaboration, strategy acquisition, real-time reasoning, robotics, and sensor fusion. RoboCup is a task for a team of multiple fast-moving robots under a dynamic environment. Although RoboCup's final target is a world cup with real robots, RoboCup offers a software platform for research on the software aspects of RoboCup. This article describes technical challenges involved in RoboCup, rules, and the simulation environment.
Recursive Estimation of Dynamic Modular RBF Networks
Kadirkamanathan, Visakan, Kadirkamanathan, Maha
In this paper, recursive estimation algorithms for dynamic modular networks are developed. The models are based on Gaussian RBF networks and the gating network is considered in two stages: At first, it is simply a time-varying scalar and in the second, it is based on the state, as in the mixture of local experts scheme. The resulting algorithm uses Kalman filter estimation for the model estimation and the gating probability estimation. Both, 'hard' and'soft' competition based estimation schemes are developed where in the former, the most probable network is adapted and in the latter all networks are adapted by appropriate weighting of the data. 1 INTRODUCTION The problem of learning multiple modes in a complex nonlinear system is increasingly being studied by various researchers [2, 3, 4, 5, 6], The use of a mixture of local experts [5, 6], and a conditional mixture density network [3] have been developed to model various modes of a system. The development has mainly been on model estimation from a given set of block data, with the model likelihood dependent on the input to the networks.
A Predictive Switching Model of Cerebellar Movement Control
Barto, Andrew G., Houk, James C.
The existence of significant delays in sensorimotor feedback pathways has led several researchers to suggest that the cerebellum might function as a forward model of the motor plant in order to predict the sensory consequences of motor commands before actual feedback is available; e.g., (Ito, 1984; Keeler, 1990; Miall et ai., 1993). While we agree that there are many potential roles for forward models in motor control systems, as discussed, e.g., in (Wolpert et al., 1995), we present a hypothesis about how the cerebellum could participate in regulating movement in the presence of significant feedback delays without resorting to a forward model. We show how a very simplified version of the adjustable pattern generator (APG) model being developed by Houk and colleagues (Berthier et al., 1993; Houk et al., 1995) can learn to control endpoint positioning of a nonlinear spring-mass system with significant delays in both afferent and efferent pathways. Although much simpler than a multilink dynamic arm, control of this spring-mass system involves some of the challenges critical in the control of a more realistic motor system and serves to illustrate the principles we propose. Preliminary results appear in (Buckingham et al., 1995).
Boosting Decision Trees
Drucker, Harris, Cortes, Corinna
We introduce a constructive, incremental learning system for regression problems that models data by means of locally linear experts. In contrast to other approaches, the experts are trained independently and do not compete for data during learning. Only when a prediction for a query is required do the experts cooperate by blending their individual predictions. Each expert is trained by minimizing a penalized local cross validation error using second order methods. In this way, an expert is able to find a local distance metric by adjusting the size and shape of the receptive field in which its predictions are valid, and also to detect relevant input features by adjusting its bias on the importance of individual input dimensions. We derive asymptotic results for our method. In a variety of simulations the properties of the algorithm are demonstrated with respect to interference, learning speed, prediction accuracy, feature detection, and task oriented incremental learning.
Reinforcement Learning by Probability Matching
Sabes, Philip N., Jordan, Michael I.
We present a new algorithm for associative reinforcement learning. The algorithm is based upon the idea of matching a network's output probability with a probability distribution derived from the environment's reward signal. This Probability Matching algorithm is shown to perform faster and be less susceptible to local minima than previously existing algorithms. We use Probability Matching to train mixture of experts networks, an architecture for which other reinforcement learning rules fail to converge reliably on even simple problems. This architecture is particularly well suited for our algorithm as it can compute arbitrarily complex functions yet calculation of the output probability is simple. 1 INTRODUCTION The problem of learning associative networks from scalar reinforcement signals is notoriously difficult.
Neuron-MOS Temporal Winner Search Hardware for Fully-Parallel Data Processing
Shibata, Tadashi, Nakai, Tsutomu, Morimoto, Tatsuo, Kaihara, Ryu, Yamashita, Takeo, Ohmi, Tadahiro
Search for the largest (or the smallest) among a number of input data, Le., the winner-take-all (WTA) action, is an essential part of intelligent data processing such as data retrieval in associative memories [3], vector quantization circuits [4], Kohonen's self-organizing maps [5] etc. In addition to the maximum or minimum search, data sorting also plays an essential role in a number of signal processing such as median filtering in image processing, evolutionary algorithms in optimizing problems [6] and so forth.
Constructive Algorithms for Hierarchical Mixtures of Experts
Waterhouse, Steve R., Robinson, Anthony J.
By applying a likelihood splitting criteria to each expert in the HME we "grow" the tree adaptively during training. Secondly, by considering only the most probable path through the tree we may "prune" branches away, either temporarily, or permanently if they become redundant. We demonstrate results for the growing and path pruning algorithms which show significant speed ups and more efficient use of parameters over the standard fixed structure in discriminating between two interlocking spirals and classifying 8-bit parity patterns. INTRODUCTION The HME (Jordan & Jacobs 1994) is a tree structured network whose terminal nodes are simple function approximators in the case of regression or classifiers in the case of classification. The outputs of the terminal nodes or experts are recursively combined upwards towards the root node, to form the overall output of the network, by "gates" which are situated at the non-terminal nodes.
A Realizable Learning Task which Exhibits Overfitting
In this paper we examine a perceptron learning task. The task is realizable since it is provided by another perceptron with identical architecture. Both perceptrons have nonlinear sigmoid output functions. The gain of the output function determines the level of nonlinearity of the learning task. It is observed that a high level of nonlinearity leads to overfitting. We give an explanation for this rather surprising observation and develop a method to avoid the overfitting. This method has two possible interpretations, one is learning with noise, the other cross-validated early stopping.