Is it more eecient to use one or several robots? Will the performance of a group of robots working in a collaborative task be enhanced if the robots can communicate with one another? What learning abilities should the robot(s) be provided with for adapting to a continuously changing environment? We address these three issues in a speciic task, namely learning the topography of an environment wh...

a simple, selective and sensitive method for the determination of trace amount of titanium (iv) based on its catalytic effect on methylene blue- ascorbic acid redox reaction has been reported. the reaction was followed spectrophotometrically by measuring the change in absorbance of methylene blue at 665 nm, 5 minutes after the initiation of the reaction. in this study experimental parameters we...

We present a neural network that learns to control approach and avoidance behaviors in a mobile robot based on a form of animal learning known as operant conditioning. Learning, which requires no supervision, takes place as the robot moves around an environment cluttered with obstacles and light sources. The neural network requires no knowledge of the geometry of the robot or of the quality, nu...

The navigation problem involves how to reach a goal avoiding obstacles in dynamic environments. This problem can be faced considering reactions and sequences of actions. Classifier Systems (CS) have proven their ability of continuos learning, however they have some problems in reactive systems. A modified CS, Reactive Classifier System (RCS), is proposed to overcome those problems. Two special ...

Local reconstruction of differential-drive mobile robots position and orientation is made possible with an accurate odometry calibration. Starting from the encoders readings, and assuming an absolute measurement available, a deterministic filter to localize the vehicle while estimating a proper set of odometric parameters is proposed. A stability analysis guarantees that the position and orient...

In many cases, a real robot application requires the navigation in dynamic environments. The navigation problem involves two main tasks: to avoid obstacles and to reach a goal. Generally, this problem could be faced considering reactions and sequences of actions. For solving the navigation problem a complete controller, including actions and reactions, is needed. Machine learning techniques has...

* 0-7803-7952-7/03/$17.00  2003 IEEE. Abstract In this paper we describe a method for the synthesis of robotic controllers using evolutionary techniques. A modified version of the recurrent neural network used for controlling the robots is evolved using Genetic Algorithm using the Variable Length Genotype approach where the genotype encodes the network. It has been discovered that separation o...

This paper is concerned with the improvement of reinforcement learning through the use of forbidden sequences of actions. A given reinforcement function can generate multiple effective behaviors. Each behavior is effective only considering the cumulative reward over time. It may not be the behavior expected by the designer. In this case, the usual solution is to modified the reinforcement funct...

background and aims: students experience some degrees of mental disorders during their life. therefore, the present study was conducted to determine the prevalence and risk factors of mental disorders among the secondary school students in ilam, iran. methods: this is a cross sectional study, carried out among the secondary school students in ilam, iran. we assessed 841 students including 446 m...

nicotine is one the chemical substance with high level of toxically. it crosses the placenta and accumulates in the developing organs of fetus. our previous investigations indicated that collagen type iv plays a key role in basement membrane of various embryonic organs. in this study we evaluated the effect of maternal nicotine exposure pre and postnatal period on collagen iv expression during ...