Predictive direct torque control with reduced ripples for induction motor drive based on T‐S fuzzy speed controller

Finite‐state model predictive control (FS‐MPC) has been widely used for controlling power converters and electric drives. Predictive torque control strategy (PTC) evaluates flux and torque in a cost function to generate an optimal inverter switching state in a sampling period. However, the existing PTC method relies on a traditional proportional‐integral (PI) controller in the external loop for speed regulation. Consequently, the torque reference may not be generated properly, especially when a sudden variation of load or inertia takes place. This paper proposes an enhanced predictive torque control scheme. A Takagi‐Sugeno fuzzy logic controller replaces PI in the external loop for speed regulation. Besides, the proposed controller generates a proper torque reference since it plays an important role in cost function design. This improvement ensures accurate tracking and robust control against different uncertainties. The effectiveness of the presented algorithms is investigated by simulation and experimental validation using MATLAB/Simulink with dSpace 1104 real‐time interface.     

Specification and evaluation of polymorphic shellcode properties using a new temporal logic

It is a well-known fact that polymorphism is one of the greatest find of malicious code authors. Applied in the context of Buffer Overflow attacks, the detection of such codes becomes very difficult. In view of this problematic, which constitutes a real challenge for all the international community, we propose in this paper a new formal language (based on temporal logics such as CTL) allowing to specify polymorphic codes, to detect them and to better understand their nature. The efficiency and the expressiveness of this language are shown via the specification of a variety of properties characterizing polymorphic shellcodes. Finally, to make the verification process automatic, this language is supported by a new IDS (Intrusion Detection System) that will also be presented in this paper.     

Contribution to the understanding of the relationship between mechanical and dielectric strengths of Alumina

The experimental evolutions of the Alumina dielectric strength versus thickness (127 μm to 2.54 mm), purity (92%, 96% and 99.5%) and crystallography (single or polycrystal) have been investigated. In order to find crucial information about the mechanism responsible for the dielectric breakdown, optical and scanning electron micrograph observations have also been performed. Each breakdown channel was found to be terminated by a crater from which matter has been extracted during the breakdown process. Investigations have been focused on the breakdown path, on the evolution of the crater size versus sample thickness and on the location of molten matter after breakdown. The results tend to confirm that the dielectric breakdown of Alumina is probably originated from a mechanical failure induced by electromechanical forces acting during the voltage application.     

Adaptive and dual data-communication trust scheme for clustered wireless sensor networks

In wireless sensor networks, trust management schemes are designed to preserve them against misbehavior of malicious sensor nodes. These schemes observe the behavior of nodes, check their conformity to what is expected, compute and assign them trust values, and avoid any interaction with untrustworthy nodes. In this paper, we introduce Adaptive and dual Data-Communication Trust scheme (ADCT) for clustered wireless sensor networks to effectively deal with untrustworthy nodes. Unlike prior works, we propose an adaptive trust function to assess the direct trust between nodes according to the application’s requirement in terms of trust severity. We also consider data trust to cope with untrustworthy nodes during the data collection despite their communication capabilities. Moreover, we use the duality data-communication trust to deal with untrustworthy recommendations when building cluster-member’s feedback at the cluster-head level. Theoretical analysis and simulation show that the trust mechanism presented in this paper provides a better cooperation with the same or even lower communication overhead compared to the latest trust management schemes proposed for clustered wireless sensor networks.     

Gender-Dependent Phenotype in Polycystic Kidney Disease Is Determined by Differential Intracellular Ca2+ Signals

Autosomal dominant polycystic kidney disease (ADPKD) is caused by loss of function of PKD1 (polycystin 1) or PKD2 (polycystin 2). The Ca²⁺-activated Cl⁻ channel TMEM16A has a central role in ADPKD. Expression and function of TMEM16A is upregulated in ADPKD which causes enhanced intracellular Ca²⁺ signaling, cell proliferation, and ion secretion. We analyzed kidneys from Pkd1 knockout mice and found a more pronounced phenotype in males compared to females, despite similar levels of expression for renal tubular TMEM16A. Cell proliferation, which is known to be enhanced with loss of Pkd1^−/−, was larger in male when compared to female Pkd1^−/− cells. This was paralleled by higher basal intracellular Ca²⁺ concentrations in primary renal epithelial cells isolated from Pkd1^−/− males. The results suggest enhanced intracellular Ca²⁺ levels contributing to augmented cell proliferation and cyst development in male kidneys. Enhanced resting Ca²⁺ also caused larger basal chloride currents in male primary cells, as detected in patch clamp recordings. Incubation of mouse primary cells, mCCDcl1 collecting duct cells or M1 collecting duct cells with dihydrotestosterone (DHT) enhanced basal Ca²⁺ levels and increased basal and ATP-stimulated TMEM16A chloride currents. Taken together, the more severe cystic phenotype in males is likely to be caused by enhanced cell proliferation, possibly due to enhanced basal and ATP-induced intracellular Ca²⁺ levels, leading to enhanced TMEM16A currents. Augmented Ca²⁺ signaling is possibly due to enhanced expression of Ca²⁺ transporting/regulating proteins.     

Effect of in vitro fertilization on gene expression and development of mouse preimplantation embryos

In vitro culture (IVC) of preimplantation mouse embryos is associated with changes in gene expression. It is however, not known if the method of fertilization affects the global pattern of gene expression. We compared gene expression and development of mouse blastocysts produced by in vitro fertilization (IVF) versus blastocysts fertilized in vivo and cultured in vitro from the zygote stage (IVC) versus control blastocysts flushed out of the uterus on post coital day 3.5. The global pattern of gene expression was assessed using the Affymetrix 430 2.0 chip. It appears that each method of fertilization has a unique pattern of gene expression and development. Embryos cultured in vitro had a reduction in the number of trophoblastic cells (IVF 33.5 cells, IVC 39.9 cells, and 49.6 cells in the in vivo group) and, to a lesser degree, of inner cell mass cells (12.8, 11.7, and 13.8 respectively). The inner cell mass nuclei were larger after culture in vitro (140 microm(2), 113 microm(2), and 86 microm(2) respectively). Although a high number of genes (1912) was statistically different in the IVF cohort when compared with the in vivo control embryos, the magnitude of the changes in gene expression were low and only a minority of genes (29 genes) was changed more than fourfold. Surprisingly, IVF embryos were different from IVC embryos (3058 genes were statistically different, but only three changed more than fourfold). Proliferation, apoptosis, and morphogenetic pathways are the most common pathways altered after IVC. Overall, IVF and embryo culture have a profound effect on gene expression pattern and phenotype of mouse preimplantation embryos.     

A parallel adaptive tabu search approach

This paper presents a new approach for parallel tabu search based on adaptive parallelism. Adaptive parallelism was used to dynamically adjust the parallelism degree of the application with respect to the system load. Adaptive parallelism demonstrates that high-performance computing using a hundred of heterogeneous workstations combined with massively parallel machines is feasible to solve large optimization problems. The parallel tabu search algorithm includes different tabu list sizes and new intensification/diversification mechanisms. Encouraging results have been obtained in solving the quadratic assignment problem. We have improved the best known solutions for some large real-world problems.     

Parallel partitioning method (PPM): A new exact method to solve bi-objective problems

In this paper, we propose a new exact method, called the parallel partitioning method (PPM), able to solve efficiently bi-objective problems. This method is based on the splitting of the search space into several areas leading to elementary exact searches. We compare this method with the well-known two-phase method (TPM). Experiments are carried out on a bi-objective permutation flowshop problem (BOFSP). During experiments the proposed PPM is compared with two versions of TPM: the basic TPM and an improved TPM dedicated to scheduling problems. Experiments show the efficiency of the new proposed method.     

Dual-polarised CPW-fed microstrip antenna for wireless applications at 2.45 GHz

The design and fabrication of a dual-polarised microstrip antenna fed by two coplanar waveguides (CPWs) for operation at 2.45 GHz are presented. Obtained results show an impedance bandwidth of 44.3 MHz using a single layer of substrate. The simulated return loss for both polarisations is less than -35 dB, and the isolation between the ports of the antenna is better than 21 dB.