Samia Nefti-Meziani

A comprehensive review of swarm optimization algorithms.

Many swarm optimization algorithms have been introduced since the early 60’s, Evolutionary Programming to the most recent, Grey Wolf Optimization. All of these algorithms have demonstrated their potential to solve many optimization problems. This paper provides an in-depth survey of well-known optimization algorithms. Selected algorithms are briefly explained and compared with each other comprehensively through experiments conducted using thirty well-known benchmark functions. Their advantages and disadvantages are also discussed. A number of statistical tests are then carried out to determine the significant performances. The results indicate the overall advantage of Differential Evolution (DE) and is closely followed by Particle Swarm Optimization (PSO), compared with other considered approaches.

Predicting the Valence of a Scene from Observers’ Eye Movements

Multimedia analysis benefits from understanding the emotional content of a scene in a variety of tasks such as video genre classification and content-based image retrieval. Recently, there has been an increasing interest in applying human bio-signals, particularly eye movements, to recognize the emotional gist of a scene such as its valence. In order to determine the emotional category of images using eye movements, the existing methods often learn a classifier using several features that are extracted from eye movements. Although it has been shown that eye movement is potentially useful for recognition of scene valence, the contribution of each feature is not well-studied. To address the issue, we study the contribution of features extracted from eye movements in the classification of images into pleasant, neutral, and unpleasant categories. We assess ten features and their fusion. The features are histogram of saccade orientation, histogram of saccade slope, histogram of saccade length, histogram of saccade duration, histogram of saccade velocity, histogram of fixation duration, fixation histogram, top-ten salient coordinates, and saliency map. We utilize machine learning approach to analyze the performance of features by learning a support vector machine and exploiting various feature fusion schemes. The experiments reveal that ‘saliency map’, ‘fixation histogram’, ‘histogram of fixation duration’, and ‘histogram of saccade slope’ are the most contributing features. The selected features signify the influence of fixation information and angular behavior of eye movements in the recognition of the valence of images.

Soft and Stretchable Sensor Using Biocompatible Electrodes and Liquid for Medical Applications.

Abstract This article introduces a soft and stretchable sensor composed of silicone rubber integrating a conductive liquid-filled channel with a biocompatible sodium chloride (NaCl) solution and novel stretchable gold sputtered electrodes to facilitate the biocompatibility of the sensor. By stretching the sensor, the cross section of the channel deforms, thus leading to a change in electrical resistance. The functionalities of the sensor have been validated experimentally: changes in electrical resistance are measured as a function of the applied strain. The experimentally measured values match theoretical predictions, showing relatively low hysteresis. A preliminary assessment on the proposed sensor prototype shows good results with a maximum tested strain of 64%. The design optimization of the saline solution, the electrodes, and the algebraic approximations derived for integrating the sensors in a flexible manipulator for surgery has been discussed. The contribution of this article is the introduction of the biocompatible and stretchable gold sputtered electrodes integrated with the NaCl-filled channel rubber as a fully biocompatible solution for measuring deformations in soft and stretchable medical instruments.

3D perception from binocular vision for a low cost humanoid robot NAO

Depth estimation is a classical problem in computer vision and after decades of research many methods have been developed for 3D perception like magnetic tracking, mechanical tracking, acoustic tracking, inertial tracking, optical tracking using markers and beacons. The vision system allows the 3D perception of the scene and the process involves: (1) camera calibration, (2) image correction, (3) feature extraction and stereo correspondence, (4) disparity estimation and reconstruction, and finally, (5) surface triangulation and texture mapping. The work presented in this paper is the implementation of a stereo vision system integrated in humanoid robot. The low cost of the vision system is one of the aims to avoid expensive investment in hardware when used in robotics for 3D perception. In our proposed solution, cameras are highly utilized as in our opinion they are easy to handle, cheap and very compatible when compared to the hardware used in other techniques. The software for the automated recognition of features and detection of the correspondence points has been programmed using the image processing library OpenCV (Open Source Computer Vision) and OpenGL (Open Graphic Library) is used to display the 3D models obtained from the reconstruction. Experimental results of the reconstruction and models of different scenes are shown. The results obtained from the program are evaluated comparing the size of the objects reconstructed with that calculated by the program. Implementation of a stereo vision system integrated in humanoid robot is proposed.Low cost robotics vision system for 3D perception avoids expensive hardware cost.Cameras are highly utilized as they are easy to handle, cheap and very compatible.

Valuable experimental model of contraction pneumatic muscle actuator

Modelling of pneumatic muscle actuators “PMA” is one of the valued challenges in soft robotic researches, which is still under modification for the McKibben artificial muscle. Accurate force, length and position models allow for the wide use of make the continuum robot arm in industrial and medical applications. Moreover, accurate control can be achieved. This paper presents new formulas to model the length of contraction PMA. The sigmoidal shape of contraction length characteristics makes the sigmoid function a suitable form to model, which its coefficients depend on the nominal length “Lo”. Furthermore, we modified the existing force model by calculating the most affected parameters. Then we are modelling the angle of the arm. The three proposed models make it easy to track the length (position), the force of PAMs and position angle of PMA arm.

Variable stiffness Mckibben muscles with hydraulic and pneumatic operating modes

Abstract McKibben muscles have been shown to have improved stiffness characteristics when operating hydraulically. However when operating pneumatically, they are compliant and so have potential for safer physical human–robot interaction. This paper presents a method for rapidly switching between pneumatic and hydraulic modes of operation without the need to remove all hydraulic fluid from the actuator. A compliant and potentially safe pneumatic mode is demonstrated and compared with a much stiffer hydraulic mode. The paper also explores a combined pneumatic/hydraulic mode of operation which allows both the position of the joint and the speed at which it reacts to a disturbance force to be controlled.

Wrist rehabilitation exoskeleton robot based on pneumatic soft actuators

The aim of this paper is to describe the design of a soft, wearable splint for wrist joint rehabilitation, based on pneumatic soft actuators. The extensor bending and the contraction types of pneumatic soft actuators have been adopted in this study. These actuators are shown to be appropriate by examining their characteristics. The main contributions of this study are developing a safe, lightweight, soft and small actuator for direct human interaction, designing a novel single portable wearable soft robot capable of performing all wrist rehabilitation movements, and using low-cost materials to create the device. Three modes of rehabilitation exercises in the exoskeleton are involved: Flexion/Extension, Radial/Ulnar deviation, and circular movements.

The design and mathematical modelling of novel extensor bending pneumatic artificial muscles (EBPAMs) for soft exoskeletons

This article presents the development of a power augmentation and rehabilitation exoskeleton based on a novel actuator. The proposed soft actuators are extensor bending pneumatic artificial muscles. This type of soft actuator is derived from extending McKibben artificial muscles by reinforcing one side to prevent extension. This research has experimentally assessed the performance of this new actuator and an output force mathematical model for it has been developed. This new mathematical model based on the geometrical parameters of the extensor bending pneumatic artificial muscle determines the output force as a function of the input pressure. This model is examined experimentally for different actuator sizes. After promising initial experimental results, further model enhancements were made to improve the model of the proposed actuator. To demonstrate the new bending actuators a power augmentation and rehabilitation soft glove has been developed. This soft hand exoskeleton is able to fit any adult hand size without the need for any mechanical system changes or calibration. EMG signals from the human hand have been monitored to prove the performance of this new design of soft exoskeleton. This power augmentation and rehabilitation wearable robot has been shown to reduce the amount of muscles effort needed to perform a number of simple grasps. A novel soft bending actuators are developed.New mathematical output force model based on the geometrical parameters for the new actuator is developed.Model enhancements were made to improve the model of the proposed actuators.EMG signals from the human hand have been monitored to prove the performance of this new design of soft exoskeleton.A power augmentation and rehabilitation exoskeleton based on a novel actuator is presented.

Power assistive and rehabilitation wearable robot based on pneumatic soft actuators

The aim of this paper is to describe the design of a soft, wearable glove for power assisted and rehabilitation, based on pneumatic soft actuators. The extensor bending type of pneumatic soft actuators was used in this study, which proved these actuators are appropriate by examining their characteristics. A proposed solution for a release movement is presented. Experimental results show this solution works efficiently. Electromyography (EMG) signals are monitored to examine the proposed prototype. The proposed glove provides assistive power for multi-griping and multi-pinching movements depending on the human intention. Elderly, partially disabled and strenuous workers can use this glove. An efficient control algorithm used, depending on signals from sensors located within the glove, that capture the movement type and bending angle to provide appropriate assistance. A wide range of rehabilitation exercises can be carried out using this soft wearable glove.

Ontology enhancing process for a situated and curiosity-driven robot

Nowadays, robots need to be able to interact with humans and objects in a flexible way and should be able to share the same knowledge (physical and social) of the human counterpart. Therefore, there is a need for a framework for expressing and sharing knowledge in a meaningful way by building the world model. In this paper, we propose a new framework for human-robot interaction using ontologies as powerful way of representing information which promote the sharing of meaningful knowledge between different objects. Furthermore, ontologies are powerful notions able to conceptualise the world in which the object such as Robot is situated. In this research, ontology is considered as improved solution to the grounding problem and enables interoperability between human and robot. The proposed system has been evaluated on a large number of test cases; results were very promising and support the implementation of the solution. A new framework for human-robot interaction is proposed.A meaningful representation of the world model by using ontologies is implemented.We propose a framework that solves the grounding problem in the area of human-robot collaboration.