Adaptive Fourier Series Neural Network PID Controller

In this work, an Adaptive Neural Networks PID controller structure, called Adaptive Fourier Series Neural Networks PID controller (AFSNNPID), is developed. The main objective is to obtain a simple controller for nonlinear systems that can be tuned online to reject perturbations effect and compensate the system parameters variation. Due to its simple architecture and very attractive proprieties, the Fourier Series Neural Network (FSNN) is used to online adjust the parameters of the PID controller. Furthermore, using the delta-rule algorithm, the adaptation dynamics of the FSNN is globally stable. The design procedure of the proposed controller and the stability analysis of the closed loop system using the small gain theorem are given. To assess the effectiveness of the proposed control scheme, the control of a 3-DOF robot arm manipulator is considered and a comparative study, using the adaptive neural network PID controller and the particle swarm optimization based PID controller, is carried out. The obtained results, through the experimental study, indicate that the AFSNNPID controller presents better control performance than the other controllers.

     

Analyzing the ZnO and CH₃NH₃PbI₃ as Emitter Layer for Silicon Based Heterojunction Solar Cells

Today, it has become an important task to modify existing traditional silicon-based solar cell factory to produce high-efficiency silicon-based heterojunction solar cells, at a lower cost. Therefore, the aim of this paper is to analyze CH₃NH₃PbI₃ and ZnO materials as an emitter layer for p-type silicon wafer-based heterojunction solar cells. CH₃NH₃PbI₃ and ZnO can be synthesized using the cheap Sol-Gel method and can form n-type semiconductor. We propose to combine these two materials since CH₃NH₃PbI₃ is a great light absorber and ZnO has an optimal complex refractive index which can be used as antireflection material. The photoelectric parameters of n-CH₃NH₃PbI₃/p-Si, n-ZnO/p-Si, and n-Si/p-Si solar cells have been studied in the range of 20–200 nm of emitter layer thickness. It has been found that the short circuit current for CH₃NH₃PbI₃/p-Si and n-ZnO/p-Si solar cells is almost the same when the emitter layer thickness is in the range of 20–100 nm. Additionally, when the emitter layer thickness is greater than 100 nm, the short circuit current of CH₃NH₃PbI₃/p-Si exceeds that of n-ZnO/p-Si. The optimal emitter layer thickness for n-CH₃NH₃PbI₃/p-Si and n-ZnO/p-Si was found equal to 80 nm. Using this value, the short-circuit current and the fill factor were estimated around 18.27 mA/cm² and 0.77 for n-CH₃NH₃PbI₃/p-Si and 18.06 mA/cm² and 0.73 for n-ZnO/p-Si. Results show that the efficiency of n-CH₃NH₃PbI₃/p-Si and n-ZnO/p-Si solar cells with an emitter layer thickness of 80 nm are 1.314 and 1.298 times greater than efficiency of traditional n-Si/p-Si for the same sizes. These findings will help perovskites materials to be more appealing in the PV industry and accelerate their development to become a viable alternative in the renewable energy sector.     

Towards a Complete SNMP-Based Supervision of System-on-Chips

This work proposes an adaptation of classical network management protocols for the purpose of a deep testing and management of network-based electronic systems such as routers, switches, and personal computers. The basic idea of this work is to extrapolate the advantages of network management functions (monitoring, control, test…) to the level of an electronic device. To this end, the proposed approach starts very early in the design process of integrated circuits where the concept of managed integrated circuit is introduced. A widely known design-for-test (DFT) technique is extended to render it useful through classical TCP/IP networks. The suggested solution is described and its efficiency is illustrated through extensive experimentations.     

Optimal order release dates for two-level assembly systems with stochastic lead times at each level

In this paper, we examine an optimisation problem for component replenishment in two-level assembly systems under stochastic lead times. The Assembly-to-Order principle is applied. The demand for a finished product and its planned due date are known. The capacity of the assembly system at each level is considered infinite. At each level, the assembly process starts when all the required components or semi-finished items are available. At the second level, the components are ordered from external suppliers and order release dates are decision variables of the problem. A backlogging cost is incurred if the finished product demand is satisfied after the planned due date. If the finished product, a given component or a semi-finished product is available before the corresponding assembly date, an inventory holding cost is considered. Genetic algorithms (GA) reinforced with different techniques are developed to find order release dates that minimise the total expected cost. A Branch and Bound method is also developed to assess the effectiveness of the hybrid GA. Regardless of the number of components and the variability of the costs related to the finished product, the experimental results indicate that the proposed GA are highly efficient.     

A sliding-mode observer for high-performance sensorless control of PMSM with initial rotor position detection

This paper proposes a new method to detect the initial rotor position at standstill of permanent magnet synchronous motor (PMSM). To estimate rotor position and rotor speed from the back electromotive force (EMF) voltage, we apply sensorless speed control based on sliding-mode observer (SMO). The initial rotor position is detected by using a suitable high-frequency sequence of voltage pulses intermittently applied to the stator windings at standstill. With this approach, we managed to minimise the error on the estimated position to 3.75° electrical degrees without additional materials and uncomplicated calculations. The stability of the proposed SMO was verified using the Lyapunov method. Numerical simulations and experiments demonstrate that the novel SMO method can effectively estimate rotor position and speed with achievement of good static and dynamic performance. The experimental implementation is carried out on powerful dSpace DS1103 controller board based on the digital signal processor (DSP) TMS320F240.     

Growth and Luminescence of Polytypic InP on Epitaxial Graphene

Van der Waals epitaxy is an attractive alternative to direct heteroepitaxy where the forced coherency at the interface cannot sustain large differences in lattice parameters and thermal expansion coefficients between the substrate and the epilayer. Herein, the growth of monocrystalline InP on Ge and SiO₂/Si substrates using graphene as an interfacial layer is demonstrated. Micrometer‐sized InP crystals are found to grow with interfaces of high crystalline quality and with different degrees of coalescence depending on the growth conditions. Some InP crystals exhibit a polytypic structure, consisting of alternating zinc‐blende and wurtzite phases, forming a type‐II homojunction with well (barrier) width of about 10 nm. The optical properties, investigated using room temperature nano‐cathodoluminescence, indicate the signatures of the direct optical transitions at 1.34 eV across the gap of the zinc‐blende phase and the indirect transitions at ≈ 1.31 eV originating from the alternating zinc‐blende and wurtzite phases. Additionally, the InP nanorods, found growing mainly on the graphene/SiO₂/Si substrate, show optical transition across the gap of the wurtzite phase at ≈ 1.42 eV. This demonstration of InP growth on graphene and the correlative study between the structure and optical properties pave the way to develop hybrid structures for potential applications in integrated photonic and optoelectronic devices.     

Chaotic watermark for blind forgery detection in images

In this paper, a new chaos based watermarking scheme for effective tamper detection in images is proposed. The proposed scheme is able to detect any possible forgery and spot the areas which have been tampered. To improve the efficiency of the proposed scheme, a binary watermark is constructed from the image itself, which makes the watermark unique for every image and guarantee the blindness in the detection process. To guarantee the security of the proposed scheme, chaotic maps are used to complicate the embedding and the detection process to reduce the vulnerability to different attacks. Experimental results and security analysis show that the proposed scheme achieves superior tamper detection under common attacks.     

Classification of moroccan olive cultivars by linear discriminant analysis applied to ATR–FTIR spectra of endocarps

The potential of FTIR combined with chemometrics was studied to classify five Moroccan varieties of olives by analysis on the endocarps. Attenuated total reflectance (ATR) enabled the samples to be examined directly in the solid state. The spectral data were subjected to a preliminary derivative elaboration based on the Norris gap algorithm to reduce the noise and extract larger analytical information. Linear discriminant analysis (LDA) was adopted as classification method, and Principle component analysis (PCA) was employed to compress the original data set into a reduced new set of variables before LDA. The calibration set was built by using the IR data from seventy‐five samples scanned in reflectance mode, and the ranges 3000–2400 and 2300–600 cm^?1 were selected because furnishing the most useful analytical information. PCA allowed clustering the samples in five classes by using the first two principal components with an explained variance of 98.16%. Application of LDA on an external test set of twenty‐five samples enabled to classify them into five variety groups with a correct classification of 92.0%.     

Behavior of T-shaped reinforced concrete beams partially confined by structural steel

External confinement of reinforced concrete (R/C) members with structural steel sections or fiber reinforcing wraps is commonly used to improve the flexural behavior of structural members. Flexural strengthening of R/C beams by external steel members is among the most effective and convenient techniques. A study is presented in this paper investigating the flexural behavior of R/C beams having T cross-sections partially confined (P/C) by a combination of various steel members connected together by intermittent batten plates. Four R/C specimens, representing dropped beams in solid slabs, were tested. One control beam had no confinement whereas the three other beams had four steel angles simply wrapped and tied around the stem by batten plates, two angles at the bottom corners of the stem and the other two angles at the stem-flange junctions. Two plates were placed on the top surface of the flange and connected by studs to the two angles at the bottom of the flange. The resulting P/C beams are categorized as partial composite beams because no shear connectors were used between the R/C beam and the jacketing bottom-tension steel angles as in the case of conventional composite beams. All specimens were tested in positive bending under two points loading. Test results revealed an enhancement in the flexural behavior, particularly in the post-yield range of loading, and ductility due to the proposed strengthening and partial composite effect. The number and spacing of the intermittent battens played a significant role in the behavior of the strengthened specimens. Analytical values of loads and deformations at yield and ultimate loading showed good agreement with the measured values.