We study the minimal normal completion problem: given A ∈ Cn×n, how do we find an (n+q)×(n+q) normal matrix Aext := ( A A12 A21 A22 ) of smallest possible size? We will show that this smallest number q of rows and columns we need to add, called the normal defect of A, satisfies nd(A) ≥ max{i−(AA∗ −A∗A), i+(AA∗ −A∗A)}, where i±(M) denotes the number of positive and negative eigenvalues of the He...

A key role for the knowledge sharing on the Web is the constructive interaction between system and user. It is presented an application implemented on Cicerobot, a RWI B21 autonomous robot. It is based on a cognitive architecture and works on tasks related with guided tours in the Archaeological Museum of Agrigento. Interaction between Cicerobot and the user is based on a first step towards sem...

Mobile robots need to navigate in their environment in order to perform useful tasks. Doors appear in almost every office-like indoor environment and they have to be crossed often during the navigation process. We present in this paper a new approach that uses visual information to anticipate that a door has to be crossed. Combining then visual information with ultrasonic sensors, the robot app...

By observing the execution of their actions, cognitive robots become aware of their behavior. We describe a system that acquires such knowledge, and uses it to reflect future actions to autonomously avoid failures and optimize future actions. The system has three types of motor control knowledge, which are represented at different levels of abstraction, and acquired in different ways: 1) declar...

In order to address the question whether Hayek might have been an Agent-based Computational Economist (ACE) avant-la-lettre, we consider an ACE model concerning the phenomenon of information contagion. Alongside increasing returns, network externalities, and information cascades, information contagion has been presented in the literature as an explanation for particular patterns of macrobehavio...

In this study a sensor integration scheme to improve the capabilities of an indoor robot, has been developed such as mapping, collision avoidance and path planning. This integration has been carried out using a sonar ranging system and a 2D laser scanner, with participation of other sensors. The main goal of the integration is to reinforce the robustness of the overall system and overcome the s...