Elementary Behaviors Research Articles

Stigmergic cooperation of autonomous robots

This paper presents a general and formal approach to designing robot controllers. It is based on structuring the controller into subsystems dealing with effectors, receptors, inter-agent transmission and internal memory. The behaviour of the controller is governed by transition functions. They are the basis for the definitions of robot behaviours. A systematic method of partitioning the task of a robot into separate bio-inspired elementary behaviours and the method of composing those behaviours into actions performed by the robot in the real environment are presented. Those general considerations are illustrated by an example of the design of behavioural controllers for robots executing a joint transportation task. The robots only observe the effects of the others activities in the environment (stigmergy). The presented specific solution to the joint box pushing example has its own merits, however the paper focuses on the general aspects of formal approach to controller design of multi-robot systems.

Computational framework for behavioural modelling of neural subsystems

This paper presents a new approach to the problem of modelling living system dynamics. Our point of view claims the fact that behind the biological apparent complexity, a hidden simplicity may appear when a suitable modelling is developed. The framework is inspired on the computing features of biological systems by involving a set of elementary standard behaviours that can be combined in order to emulate more complex behaviours. The algebraic formalization is based on both a recursive primitive operation defined by a table which models the elementary behaviours and a multilevel operating mode that carries out behaviour combinations. A parametric architecture implements the model, providing a good trade-off between time delay calculation and memory requirements. In this paper, the simulation of neural subsystems is considered as an application. The comparison with other simulation techniques outlines the capabilities of our method to provide an accurate modelling together with a very simple circuit implementation.

Research on Measuring of Stress and Coping Behavior ofElementary Students through Drawing of People in the Rain (PITR)

Research on Measuring of Stress and Coping Behavior ofElementary Students through Drawing of People in the Rain (PITR)

The null-space-based behavioral control for autonomous robotic systems

In this paper a new behavior-based approach for the control of autonomous robotic systems is proposed. The so-called null-space-based behavioral (NSB) control differs from the other existing methods in the behavioral coordination, i.e., in the way the outputs of the single elementary behaviors are combined to compose a complex behavior. The proposed approach is compared with the main existing approaches while two experimental case studies, performed with a Khepera II mobile robot, are reported to validate its effectiveness.

A computer model of elementary social behavior

A computer model of elementary social behavior

An Investigation into Information Needs and Information Seeking Behavior of Elementary and Middle School Teachers Teaching Indigenous Courses

An Investigation into Information Needs and Information Seeking Behavior of Elementary and Middle School Teachers Teaching Indigenous Courses

Courtship behaviour of Drosophila melanogaster revisited

Nearly all studies of Drosophila melanogaster courtship have focused exclusively on male behaviour. Female precopulatory behaviour is often relegated to ‘accept’ or ‘reject’ mating, and how female behaviour interacts with that of males remains largely unknown. Using a video-computing approach, we measured 10 behavioural states and 22 elementary behaviours that occur during the precopulatory phase of Canton-S (Cs) flies. Male and female behaviours were studied under a variety of social conditions. This allowed us to identify which one(s) is relevant to courtship or to general activity. Our analysis showed that the courtship repertoire was not constant over time, as female and male behaviours varied during courtship, and that virgin Cs females showed several behavioural sequences whose frequency, latency and total duration could predict their mating success. The most striking index of females' willingness to copulate was the way they extruded the ovipositor: a partial extrusion stimulated male courtship, whereas total extrusion inhibited it. Furthermore, females that mated preened their abdomen more frequently than did females that did not mate. We also observed that male sexual activity was strongly increased when the female emitted a tiny volatile droplet at the tip of the ovipositor. We hypothesized that partial ovipositor extrusion, droplet emission and abdominal preening are related behaviours that result in the active dispersion of compounds spread on the female's abdomen. Such a detailed picture of the precopulatory behaviours should allow better characterization of the sensory stimuli exchanged during courtship in Drosophila.

Behavioral and distributed architecture of control for minimalist mobile robots

This paper describes a specific behavioral and reactive architecture of control applied to complex and cooperative tasks. The coordination between elementary behaviors (layers of skills) is insured using both hierarchical and fusion action mechanisms. Indeed, competitive and cooperative mechanisms are gathered giving thus an Hybrid and Hierarchical Action Selection Process Hybrid-HASP in order to perform complex box-pushing tasks by a set of minimalist mobile robots. Specific low-level behaviors, called altruistic behaviors reproducing the simple interaction (attraction/repulsion) of individuals constituting societies of insects are integrated into the architecture of control in order to improve the efficiency of robots coordination. The analysis of a great number of simulations allows us to have convincing statistical results which show among others, the existence of an optimal number of robots to achieve the cooperative task and underline the importance of implicit communications induced by the altruistic behaviors.

Multi-robot concurrent learning of cooperative behaviours for the tracking of multiple moving targets

Reinforcement learning has been extensively studied and applied for generating cooperative behaviours in multi-robot systems. However, traditional reinforcement learning algorithms assume discrete state and action spaces with finite number of elements. This limits the learning to discrete behaviours and cannot be applied to most real multi-robot systems that inherently require appropriate combinations of different elementary behaviours. To address this problem, we design a distributed learning controller that integrates reinforcement learning with behaviour-based control networks. This learning controller can enable the robots to generate appropriate control policy without the need for human design or hardcoding. Furthermore, to address the problems in concurrent learning, we propose a distributed learning control algorithm to coordinate the concurrent learning processes. The distributed learning controller and learning control algorithm are applied to multi-robot tracking of multiple moving targets. The efficacy of our proposed scheme is shown through simulations.

Reinforcement learning-based group navigation approach for multiple autonomous robotic systems

In several complex applications, the use of multiple autonomous robotic systems (ARS) becomes necessary to achieve different tasks, such as foraging and transport of heavy and large objects, with less cost and more efficiency. They have to achieve a high level of flexibility, adaptability and efficiency in real environments. In this paper, a reinforcement learning (RL)-based group navigation approach for multiple ARS is suggested. Indeed, the robots must have the ability to form geometric figures and navigate without collisions while maintaining the formation. Thus, each robot must learn how to take its place in the formation, and avoid obstacles and other ARS from its interaction with the environment. This approach must provide ARS with the capability to acquire the group navigation approach among several ARS from elementary behaviors by learning with trialand-error search. Then, simulation results display the ability of the suggested approach to provide ARS with capability to navigate in a group formation in dynamic environments. With its cooperative behavior, this approach makes ARS able to work together to successfully fulfill the desired task.

Applying a pragmatics-based creativity-fostering technique to requirements elicitation

This paper proposes the application to requirements elicitation of an innovative creativity fostering technique based on a model of the pragmatics of communication, the Elementary Pragmatic Model (EPM). The EPM has been used to define a creative process, called EPMcreate (EPM Creative Requirements Engineering TEchnique) that consists of sixteen steps. In each step, the problem is analyzed according to one elementary behavior identified by the EPM. Each behavior suggests that the analyst look at the problem from a different combination of users’ viewpoints. The feasibility and effectiveness of the technique in requirements elicitation was demonstrated by experiments on two projects with very different characteristics. Each experiment compared the performances of two analysis teams, one of which used EPMcreate and the other of which used brainstorming. The results of both experiments highlights the higher effectiveness of EPMcreate. Additional data from the experiments are examined for other insights into how and why EPMcreate is effective.

The Identification of Valid Syndromes in Disturbed Reading and Spelling Behavior

As yet, psychoeducational practice lacks a reliable and valid set of established classifications of learning behaviors, which is an indispensable starting point for the diagnosis of a child's problems. This paper reports an epidemiology cal study in which we collected descriptive behavioral data from a fairly representative sample (N= 150) of Dutch third-grade children who show severe learning problems. These children were described by their teachers (N= 150) with respect to their behavioral responses to a set of reading and spelling tasks that are commonly used in Dutch elementary reading and spelling instruction. Cluster analyses resulted in the identification of four syndromes in elementary reading and spelling behavior. Further analyses, based both on the epidemiological data and on further data collected in additional small-scale studies, show these four syndromes to be both reliable and valid.

Teaching Bayesian behaviours to video game characters

This article explores an application of Bayesian programming to behaviours for synthetic video games characters. We address the problem of real-time reactive selection of elementary behaviours for an agent playing a first person shooter game. We show how Bayesian programming can lead to condensed and easier formalisation of finite state machine-like behaviour selection, and lend itself to learning by imitation, in a fully transparent way for the player.

Maze exploration behaviors using an integrated evolutionary robotics environment

This paper presents results generated with a new evolutionary robotics (ER) simulation environment and its complementary real mobile robot colony research test-bed. Neural controllers producing mobile robot maze searching and exploration behaviors using binary tactile sensors as inputs were evolved in a simulated environment and subsequently transferred to and tested on real robots in a physical environment. There has been a considerable amount of proof-of-concept and demonstration research done in the field of ER control in recent years, most of which has focused on elementary behaviors such as object avoidance and homing. Artificial neural networks (ANN) are the most commonly used evolvable controller paradigm found in current ER literature. Much of the research reported to date has been restricted to the implementation of very simple behaviors using small ANN controllers. In order to move beyond the proof-of-concept stage our ER research was designed to train larger more complicated ANN controllers, and to implement those controllers on real robots quickly and efficiently. To achieve this a physical robot test-bed that includes a colony of eight real robots with advanced computing and communication abilities was designed and built. The real robot platform has been coupled to a simulation environment that facilitates the direct wireless transfer of evolved neural controllers from simulation to real robots (and vice versa). We believe that it is the simultaneous development of ER computing systems in both the simulated and the physical worlds that will produce advances in mobile robot colony research. Our simulation and training environment development focuses on the definition and training of our new class of ANNs, networks that include multiple hidden layers, and time-delayed and recurrent connections. Our physical mobile robot design focuses on maximizing computing and communications power while minimizing robot size, weight, and energy usage. The simulation and ANN-evolution environment was developed using MATLAB. To allow for efficient control software portability our physical evolutionary robots (EvBots) are equipped with a PC-104-based computer running a custom distribution of Linux and connected to the Internet via a wireless network connection. In addition to other high-level computing applications, the mobile robots run a condensed version of MATLAB, enabling ANN controllers evolved in simulation to be transferred directly onto physical robots without any alteration to the code. This is the first paper in a series to be published cataloging our results in this field.

Gelation, Shear-Thinning and Shear-Thickening in Cement Slurries

Gelation, Shear-Thinning and Shear-Thickening in Cement Slurries — The rheological behavior of cement slurries may be described in terms of a few elementary behaviors: - the rapid formation of a gel, at rest; - the collapse of this gel under a critical stress directly related to the strength of the interparticle forces; - the progressive destruction of the gel fragments under moderate shear rate, with an increasingly shear-thinning behavior as the elementary particles gets smaller; - the reconstruction, at high shear rate, of shear-resistant structures, probably as chains of grains at contact; - complete jamming, possibly. We analyze the transition mechanisms from one step to the next one. We show how the addition of a dispersing agent favors shear-thickening at the expense of shear-thinning and how the control of the particle surface state and of interparticle friction restricts shear-thickening and the risk of jamming.

Behavior-based dual dynamic agent architecture

The objective of the architecture is to make agent promptly and adaptively accomplish tasks in the real-time and dynamic environment. The architecture is composed of elementary level behavior layer and high level behavior layer. In the elementary level behavior layer, the reactive architecture is introduced to make agent promptly react to events; in the high level behavior layer, the deliberation architecture is used to enhance the intelligence of the agent. A confidence degree concept is proposed to combine the two layers of the architecture. An agent decision making process is also presented, which is based on the architecture. The results of experiment in RoboSoccer simulation team show that the proposed architecture and the decision process are successful.

Cyclic Pressuremeter Loading and Liquefaction Properties of Sands

Based on a series of cyclic cavity expansion tests carried out on a thick hollow cylinder apparatus (HCC) and on mini-pressuremeter tests performed in a calibration chamber, a method is proposed to establish a reliable correlation between the result of a “reference” cyclic expansion test carried out in a sand, in terms of cavity volume accumulation after a certain number of cycles, and the elementary behaviour of the same sand as observed upon undrained cyclic triaxial tests, in terms of number of cycles necessary to reach cyclic mobility or true liquefaction. The strong similarities observed between drained cyclic expansion test (non homogeneous test) and undrained triaxial test (homogeneous test) allow valuable correlations to be obtained between the results of both types of tests. A first validation of the method proposed is performed by comparing the liquefaction properties of two different sands with same initial conditions, and shows a good discriminating power of the method. Finally, the necessity of further validation of the method, in particular, a validation based on the performance of real in situ pressuremeter tests on sandy sites is mentioned.

Dissolution of Niobium Particles during Ti-6Al-7Nb Sintering

The Ti-6Al-7Nb alloy, with a+β microstructure, was commercially developed aiming the replacement of Ti-6Al-4V alloy in the manufacture of surgical implants owing to its largest biocompatibility. The alloy processing by powder metallurgy eases the obtainment of parts with complex geometry and probably, cheaper. Samples of this alloy were obtained from hot uniaxial pressing of the elementary powders, in vacuum. The pressing was carried out in the range 700-1500°C with compaction pressures of 20MPa. The alloy was characterized by means of scanning electron microscopy, X-ray diffraction, differential thermal analysis (DTA), Vickers microhardness measurements and density. In this work, the elementary powders behavior was investigated during sintering stage. The niobium particles act as β-phase nucleator agent and command the growth of the Widmanstatten microstructure.

CYCLIC PRESSUREMETER LOADING AND LIQUEFACTION PROPERTIES OF SANDS

Based on a series of cyclic cavity expansion tests carried out on a thick hollow cylinder apparatus (HCC) and on mini-pressuremeter tests performed in a calibration chamber, a method is proposed to establish a reliable correlation between the result of a reference cyclic expansion test carried out in a sand, in terms of cavity volume accumulation after a certain number of cycles, and the elementary behaviour of the same sand as observed upon undrained cyclic triaxial tests, in terms of number of cycles necessary to reach cyclic mobility or true liquefaction. The strong similarities observed between drained cyclic expansion test (non homogeneous test) and undrained triaxial test (homogeneous test) allow valuable correlations to be obtained between the results of both types of tests. A first validation of the method proposed is performed by comparing the liquefaction properties of two different sands with same initial conditions, and shows a good discriminating power of the method. Finally, the necessity of further validation of the method, in particular, a validation based on the performance of real in situ pressuremeter tests on sandy sites is mentioned.

A Dynamical Model of Visually-Guided Steering, Obstacle Avoidance, and Route Selection

Using a biologically-inspired model, we show how successful route selection through a cluttered environment can emerge from on-line steering dynamics, without explicit path planning. The model is derived from experiments on human walking performed in the Virtual Environment Navigation Lab (VENLab) at Brown. We find that goals and obstacles behave as attractors and repellors of heading, the direction of locomotion, for an observer moving at a constant speed. The influence of a goal on turning rate increases with its angle from the heading and decreases exponentially with its distance; the influence of an obstacle decreases exponentially with angle and distance. Linearly combining goal and obstacle terms allows us to simulate paths through arbitrarily complex scenes, based on information about obstacles in view near the heading direction and a few meters ahead. We simulated the model on a variety of scene configurations and observed generally efficient routes, and verified this behavior on a mobile robot. Discussion focuses on comparisons between dynamical models and other approaches, including potential field models and explicit path planning. Effective route selection can thus be performed on-line, in simple environments as a consequence of elementary behaviors for steering and obstacle avoidance.