Comparative Study of Different DC/DC Power Converter for Optimal PV System Using MPPT (P&O) Method

The objective of this work is to show when and how to choose the type of DC/DC power converter that must be introduced in a stand alone PV solar system’s optimization process, which is necessary to characterize the area’s climatic conditions of the system implementation, take into account the partial shading effect on the Photovoltaic Generator (PVG). In addition, determine the resistivity of the load that envisaged to be introduced with the help of the direct coupling responses of the PVG. Based on the MATLAB/Simulink software and the PVG data sheet choice, we could plot the current-voltage (I-V) and power-voltage (P-V) characteristic, using the manufacturer data and determining the maximum power point (MPP), as a function of the area’s weather conditions variations, at the same time observing the direct coupling response of the load adapted to the PVG. From this observation, we can specify the DC/DC power converter type to be introduced in the production optimization process of a standalone PV solar system. Thus, we must use a Boost converter type, if the direct coupling voltages responses are higher than those of MPP responses, or a Buck converter type in the opposite case, or both at the same time Buck-Boost converter type, if we need to increase and decrease the voltage.     

Investigation on the application of solar chimney for multi-storey buildings

This paper presents investigation on the use of solar chimney (SC) in high-rise building. To this end, two small scale models of a three storey building were built. The floor dimensions of each storey are 1.2 × 2 × 1 m. Solar chimneys were integrated into the south-faced walls of one unit whereas the other unit served as a reference. Two design configurations were considered including connected and non-connected solar chimney: The first is a tall SC with an inlet opening at each floor and one outlet opening at the third floor. While for the second, an inlet and outlet openings were installed at each floor. Data recorded included room temperature, air gap temperature and velocity of the induced air flow in the solar chimney.First, a comparison between the SC building models and a common model without openings (SC) demonstrated that multi-storey solar chimney is a good alternative. Room temperature of the solar chimney model was lower than the room temperature of the common model, depending on the floor level by up to 5 °C. Next comparison between the two SC configurations showed that the best configuration is that with an inlet opening at each floor and one outlet opening at the third floor as temperature difference between room and ambient was the lowest. Reasonable agreement between the experimental data and those derived from our mathematical model developed using electric analogies validated our model. Therefore multi-storey solar chimney is an interesting option and could be applied for hot climate like in Thailand to save energy and environment.     

Optimal design of a hybrid solar–wind-battery system using the minimization of the annualized cost system and the minimization of the loss of power supply probability (LPSP)

Potou is an isolated site, located in the northern coast of Senegal. The populations living in this area have no easy access to electricity supply. The use of renewable energies can contribute to the improvement of the living conditions of these populations. The methodology used in this paper consists in Sizing a hybrid solar–wind-battery system optimized through multi-objective genetic algorithm for this site and the influence of the load profiles on the optimal configuration. The two principal aims are: the minimization of the annualized cost system and the minimization of the loss of power supply probability (LPSP).To study the load profile influence, three load profiles with the same energy (94 kW h/day) have been used.The achieved results show that the cost of the optimal configuration strongly depends on the load profile. For example, the cost of the optimal configuration decreases by 7% and 5% going from profile 1 to 2 and for those ones going from 1 to 3.     

Assessment of olive pomace wastes as flame retardants

Olive pomace (OP) is a lignocellulosic waste from olive oil industry. In order to valorize these wastes as flame retardant (FR) fillers into polymers, OP residues are milled and screened into three different fractions. Two strategies are then investigated. The first one is to modify OP particles by phosphorus molecules using radiation grafting as already done successfully with flax. Nevertheless, pyrolysis combustion flow calorimetry analyses show that the introduction of phosphorus does not promote charring of OP and flame retardancy is not significantly improved whichever the considered fraction. The second strategy is to replace pentaerythritol by OP as char source into well-known FR systems based on ammonium polyphosphate. The incorporation of such system into ethylene-vinyl acetate copolymer leads to satisfying FR performances according to cone calorimeter tests. Moreover, the presence of high amount of extractives into OP such as oleic acid does not appear detrimental. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 47715.     

The joint use of sequence features combination and modified weighted SVM for improving daily activity recognition

Two serious problems affecting the implementation of human activity recognition algorithms have been acknowledged. The first one corresponds to non-informative sequence features. The second is the class imbalance in the training data due to the fact that people do not spend the same amount of time on the different activities. To address these issues, we propose a new scheme based on a combination of principal component analysis, linear discriminant analysis (LDA) and the modified weighted support vector machines. First we added the most significant principal components to the set of features extracted using LDA. This work shows that a suitable sequence feature set combined with the modified WSVM based on our criterion classifier achieves good improvement and efficiency over the traditional used methods.     

Regional Optimal Control Problem Governed by Distributed Bi-linear Hyperbolic Systems

This paper considers the regional bi-linear control problem of an important class of hyperbolic systems. The objective is to bring the state solutions at time T close to a desired observations w ^d only on a sub-region ω along the spatial domain Ω. We prove the existence of solution by minimizing sequence method. The adjoint system of this problem is introduced and used to characterize the optimal control. A numerical approach is developed and illustrated successfully by simulations.     

Regional controllability for infinite-dimensional bilinear systems: approach and simulations

In this study, we consider a regional controllability problem for a class of distributed bilinear systems evolving in a spatial domain Ω. A feedback control is used to steer the system state close to a desired profile at a final time T, only on ω a subregion of the system domain which may be interior or on the boundary of Ω. Our purpose is to prove that an optimal control exists, and characterised as a solution to an optimality system. Numerical algorithm is given and successfully illustrated by simulations.     

Enhancing dependability through profiling in the collaborative internet of things

Multimedia Tools and Applications - The future of the Internet of Things (IoT) is the Collaborative Internet of Things (C-IoT) in which different IoT deployments collaborate to provide better...