Comprehensive modeling of mat density effect on duckweed (Lemna minor) growth under controlled eutrophication

The effect of mat density on duckweed (Lemna minor) growth was studied under controlled conditions: 12.5h a day light exposure and 342 mol m(-2) s(-1) light intensity at 20 degrees C. The plant growth was carried out in Hoagland medium for 7 days without harvesting. The results revealed a maximal biomass growth rate of 88 g-dry m(-2) (1,470 g-wet m(-2)) at an optimal initial mat density of 45 g-dry m(-2) (750 g-wet m(-2)), with removal rates for nitrogen (N) and phosphorus (P) of 483 mg-Nm(-2) d(-1) and 128 mg-Pm(-2) d(-1), respectively. A mathematical model that takes into account the mat density was developed in order to simulate the growth of Lemna minor under controlled eutrophication. Based on experiments carried out, the model exhibits a reliability of 89% . The model remains to be validated at the full-scale level.     

A Real Time Self-Tuning Motion Controller for Mobile Robot Systems

This paper proposes an intelligent controller for motion control of robotic systems to obtain high precision tracking without the need for a real-time trial and error method. In addition, a new self-tuning algorithm has been developed based on both the ant colony algorithm and a fuzzy system for real-time tuning of controller parameters. Simulations and experiments using a real robot have been addressed to demonstrate the success of the proposed controller and validate the theoretical analysis. Obtained results confirm that the proposed controller ensures robust performance in the presence of disturbances and parametric uncertainties without the need for adjustment of control law parameters by a trial and error method.      

Toward an integrated dynamic defense system for strategic detecting attacks in cloud networks using stochastic game

Telecommunication Systems - In a complex network as a cloud computing environment, security is becoming increasingly based on deception techniques. To date, the static nature of cyber networks...     

Secure IoT solution for wearable health care applications,case study Electric Imp development platform

Internet expansion affects currently diverse entities on the physical world and daily life. The democratization of the technology called Internet of Things (IoT) brings back many problems associated with the security of the transmitted data, autonomy, and ease of use, with the central constraint of gathering momentum. The use of an embedded development platform for IoT operating through Wi‐Fi and cloud technology is in our case the solution that fits the internet model objects for wearable health care application. This work involves the study and implementation of wearable IoT secure solution dedicated to health care devoted to old and dependent people. The proposed hardware, powered by solar cells, operate through smart sleep and wake up events. The relevant part of the developed IoT operating software exploits the multiagent behavior. Case study, based on the exploitation of the Electric Imp platform, is proposed.     

Auto‐management of energy in IoT networks

Wireless sensor network (WSN) based on IEEE 802.15.4 technology continues to gain considerable importance. The present work is based on this standard and a cluster tree network topology. This network is divided into many subgroups, each of which is characterized by its special IEEE parameters (beacon order [BO] and superframe order [SO]). A mathematical model for computing energy consumption was proposed to enable personal area network (PAN) coordinator to detect the current energy level in the battery. The proposed adaptive intervention is based on a comparison between the remaining energy and the diverse thresholds, which lead to an auto‐management of energy consumption. The proposed approach was evaluated using Inetmanet/Omnet++ simulator.     

Adaptive Fault Tolerant Control of Multi-time-scale Singularly Perturbed Systems

This paper studies the fault tolerant control, adaptive approach, for linear time-invariant two-time-scale and three-time-scale singularly perturbed systems in presence of actuator faults and external disturbances. First, the full order system will be controlled using ε-dependent control law. The corresponding Lyapunov equation is ill-conditioned due to the presence of slow and fast phenomena. Secondly, a time-scale decomposition of the Lyapunov equation is carried out using singular perturbation method to avoid the numerical stiffness. A composite control law based on local controllers of the slow and fast subsystems is also used to make the control law ε-independent. The designed fault tolerant control guarantees the robust stability of the global closed-loop singularly perturbed system despite loss of effectiveness of actuators. The stability is proved based on the Lyapunov stability theory in the case where the singular perturbation parameter is sufficiently small. A numerical example is provided to illustrate the proposed method.     

Contribution to the path planning of a multi-robot system: centralized architecture

The current study is set to investigate the problem of planning trajectories for a multi-robot system in a dynamic environment. The planning study is conducted in a “barrier-free” and “with obstacle” environment, based on the artificial potential field (APF) technique. This study seeks to improve the APF method in order to have good trajectory planning of a multi-robot system. Also, for multi-robot mobile systems, one of the main technical considerations is the technique used to coordinate the movements of different robots. In this paper, we proposed a centralized architecture for the trajectory planning of a multi-robot system.

     

FTC approach with actuator saturation avoidance based on reference management

In this paper, a fault recovery approach using dynamic reference modification and reconfigurable linear quadratic regulator is proposed. The idea is to modify the reference according to the system constraints, which become more strict after fault occurrence to avoid any actuator saturation and ensure system stability. The effectiveness of the proposed method is evaluated by a performance index based on tracking reference error and illustrated by an aircraft example subject to actuator faults and constrained on the actuator dynamic ranges. Copyright © 2013 John Wiley & Sons, Ltd.     

Context-aware adaptation of multimedia documents for consistent presentations

We propose in this paper a context-aware adaptation technique for SMIL encoded multimedia documents. Our approach is mainly dedicated to run in compile-time but we discuss also how it can be used in runtime. Our algorithm aims at improving the execution of a multimedia presentation. This is achieved by scheduling object pre-fetchings in the presentation while monitoring bandwidth and memory space availabilities. For this effect, a request pattern computed from the temporal graph of the SMIL specification is exploited in order to apply an optimal policy to select which objects should be pre-fetched, real time delivered or discarded, even. The algorithm can be used as a tool to evaluate and to monitor the QoS of a presentation. At compile time, it makes it possible to assess whether the QoS of a presentation can be guaranteed after enforcing specific context-oriented adaptations. At authoring stage, this algorithm can be used, for instance, to produce different alternative sub-codes, such that each one is adapted to run in a specific context. In runtime, the algorithm can provide a mechanism to monitor the elastic time computation in case of a mismatch occurrence. In order to advocate our proposal, some experimentation results performed on a simulation platform are reported.