On the existence of the Tweedie power parameter implicit estimator

Abdelaziz Ghribi,Aymen Hassin,Afif Masmoudi 대한수학회 2022 대한수학회보 Vol.59 No.4

A special class of exponential dispersion models is the class of Tweedie distributions. This class is very significant in statistical modeling as it includes a number of familiar distributions such as Gaussian, Gamma and compound Poisson. A Tweedie distribution has a power parameter $p$, a mean $m$ and a dispersion parameter $\phi$. The value of the power parameter lies in identifying the corresponding distribution of the Tweedie family. The basic objective of this research work resides in investigating the existence of the implicit estimator of the power parameter of the Tweedie distribution. A necessary and sufficient condition on the mean parameter $m$, suggesting that the implicit estimator of the power parameter $p$ exists, was established and we provided some asymptotic properties of this estimator.

A new synthesis technique and structural, microstructural and dielectric properties of BaTiO3 nanopowder

Abdelaziz Salhi,Salaheddine Sayouri,Lahoucine Hajji,TajEddine Lamcharfi 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.12

Nanocrystalline barium titanate (BT) was synthesized by the sol gel method. The dry gel obtained was first treated in themicrowave (MW) and then calcined at different temperatures. A pure tetragonal phase was obtained under heat treatmentat 750 oC which is a relatively low temperature. SEM image reveals a fairly dense and uniform microstructure. Dielectricmeasurements performed on the sintered BaTiO3 sample at 1200 oC revealed the presence of the resonance phenomenon atfrequencies lower than 2 MHz and the existence of a weak positive temperature coefficient of resistivity (PTCR) just abovethe Curie temperature. Electric impedance analysis shows the predominance of the grain boundary (gb) contribution andenables determination of activation energies of the gb and the bulk effect and their relative capacitance and resistanceelements.

Creep Effect on Composite Beam with Perfect Steel-concrete Connection

Abdelaziz Souici,Mohamed Tehami,Nacer Rahal,M. S. Bekkouche,J. F. Berthet 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.2

In the context of primary creep, a new approach to the study of the effects of creep on the resistance of a composite beam is reported. The beam is in perfect connection, statically determinate and bent under a moderate load applied at time t0. The proposed model is based primarily on the theory of linear viscoelasticity of concretes and specifically on the principle of the irreversible law of deformation established by Dischinger. In this work, two equations of equilibrium and two other equations of compatibility at the steel-concrete interface are considered. This compatibility is rewritten according to Dischinger’s rheological equation for ageing materials while adopting elastic behaviour for the metal profile. Then, the mathematical treatment of the written compatibility should lead to the establishment of a system of two differential equations of the first order. The analytical resolution of this system provides the expressions for the generalized internal forces of the composite beam in terms of time. Using these mathematical expressions, it is easy to predict the state of internal stresses and the strains of the beam at any time, t. Finally, the proposed analytical approach is confronted with various other methods.

Adaptive Generalized Predictive Control of Fractional Order Thermal Aluminum Rod

Abdelaziz Mouhou,Abdelmajid Badri,Abdelhakim Ballouk 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.5

This paper presents the Adaptive Generalized Predictive Control (AGPC) of the heat conduction in a given aluminum rod modeled using fractional calculus. The oustaloup approximation is used to perform the integer model of the temperature of the rod, then a balanced truncation (BT) model order reduction technique is used to obtain a low integer order model used as internal prediction model of the predictive controller. In order to increase the performance metrics of the AGPC controller, the Improved Grey Wolf Optimizer (IGWO) is applied to obtain the best synthesis parameters which are the minimum prediction horizon, the maximum prediction horizon, the control horizon and the weighting factor of the control signal. Simulation results of IGWO-AGPC versus the GA based AGPC and the Ant Lion Optimizer based Fractional Order PIλDµ (ALO-FOPID) validates the effectiveness of the proposed approach.

Field Study on the Mycotoxin Binding Effects of Clay in Oreochromis niloticus Feeds and Their Impacts on the Performance as Well as the Health Status throughout the Culture Season

Abdelaziz, Mohamed,Anwer, Wael,Abdelrazek, Abeer Hamada Korean Society for Bioinformatics 2010 Interdisciplinary Bio Central (IBC) Vol.2 No.4

Total aflatoxin and ochratoxin were detected in 3 naturally contaminated fish feed samples using immune-affinity method. The results revealed that the average levels of aflatoxins in the 3 examined samples were (15, 22 and $12\;{\mu}g/kg$) respectively while the average levels of ochratoxins were (15, 6 and $6\;{\mu}g/kg$). The results of determination of the effects of clay as a mycotoxin binder on the health status and performance of Oreochromis niloticus in comparing with a control group revealed that the survival rate in control group was 81% after the end of the culture season. The results also revealed that the survival rate in group 2 which received clay treated feed was 86%. The results of regular parasitological examination revealed the identification of trichodina as external protozoa in Oreochromis niloticus from both ponds but without manifestation of disease signs. The results of bacteriological examination revealed the isolation and identification of Pseudomonas flouresence from some moribund Oreochromis niloticus. Higher performance parameters were recorded in group 2 that received feeds treated with clay which reflected in the total production which reaches 1646.47 kg while in the control pond, the total production was1308.36 kg.

Using XFEM Technique to Predict the Effect of Default on the Damage of Steel Pipe Reduced-Connection Under Bending and Pressure Loading

Abdelaziz Ahmed-Bensoltane,Mohamed Mokhtari,Habib Benzaama,Khaled Samet,Hamza Benrouba,Elamine Abdelouahed 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.1

Over the years of service and by effect of their typical geometries, pressurized tubular structures assembled by a connection of an elbow or a reduced Tee or other, are much more stressed compared to straight tubes at significant normal and tangential stresses. With the presence of faults, these connections are subsequently largely responsible for their damage. Damage to an X60 Grade 8 ”x4” steel tube Reduced Tee connection element under oriented loading and internal pressure with or without the presence of a defect was investigated in this work. Because of these advantages and in order to present the propagation of a crack, we opted for the use of the XFEM technique (extend finite element method). Numerical prediction using the ABAQUS compute code set out to assess dependent parameters such as location and type of fault as well as mode and accumulated load level. Indeed, the loading mode clearly showed a large difference between the response down to the level of damage. These results are presented by curves which present both the response of a structure in force-displacement and the crack propagation (initiation and critical length). The default location in the structure at the connection joint is oriented according to the loading mode. The different situations analyzed affect all possible cases that the element of the reduced Tee may undergo. The type of defect is related by its location according to the thickness in the form of a metal tear. This damage analysis shows that the parameters studied in the structure clearly condition the level and mode of failure as well as their response to damage.

D - C O N S T R U C T I O N

( Abdelaziz Taleb ) 한국기초조형학회 2018 한국기초조형학회 작품집 Vol.2018 No.1

Versatile Roles of Microbes and Small RNAs in Rice and Planthopper Interactions

Abdelaziz Mansour,Mannaa Mohamed Ibrahim Mohamed Ahmed,Omar Hewedy,Mostafa G. Ali,정혜정,서영수 한국식물병리학회 2022 Plant Pathology Journal Vol.38 No.5

Planthopper infestation in rice causes direct and indirect damage through feeding and viral transmission. Host microbes and small RNAs (sRNAs) play essential roles in regulating biological processes, such as metabolism, development, immunity, and stress responses in eukaryotic organisms, including plants and insects. Recently, advanced metagenomic approaches have facilitated investigations on microbial diversity and its function in insects and plants, highlighting the significance of microbiota in sustaining host life and regulating their interactions with the environment. Recent research has also suggested significant roles for sRNA-regulated genes during rice–planthopper interactions. The response and behavior of the rice plant to planthopper feeding are determined by changes in the host transcriptome, which might be regulated by sRNAs. In addition, the roles of microbial symbionts and sRNAs in the host response to viral infection are complex and involve defense-related changes in the host transcriptomic profile. This review reviews the structure and potential functions of microbes and sRNAs in rice and the associated planthopper species. In addition, the involvement of the microbiota and sRNAs in the rice–planthopper–virus interactions during planthopper infestation and viral infection are discussed.

High Gain Adaptive Observer Design for Sensorless State and Parameter Estimation of Induction Motors

Abdelaziz Maouche,Mohammed M’Saad,Bachir Bensaker,Mondher Farza 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.5

This paper addresses the problem of accurately estimating the mechanical and magnetic state variables as well as the stator and rotor resistances of induction motors using only the stator current measurements and the supplied stator voltages from an appropriate nonlinear parametrization. The involved estimation is carried out by a high gain adaptive observer designed bearing in mind the available fundamental results together with the useful implementation features, namely conception simplicity and computational efficiency. An exponential convergence of the state and parameter estimation errors is established under admissible assumptions, namely the persistent excitation requirement has been particularly reduced thanks to the introduction of unknown parameter characteristic indices. The effectiveness of the adaptive observer is highlighted throughout simulation results involving a typical induction motor.

Inhibitory Effects of Two Varieties of Tunisian Pomegranate (Punica granatum L.) Extracts on Gastrointestinal Transit in Rat

Abdelaziz Souli,Hichem Sebai,Kais Rtibi,Latifa Chehimi,Mohsen Sakly,Mohamed Amri,Jamel El-Benna,Lamjed Marzouki 한국식품영양과학회 2015 Journal of medicinal food Vol.18 No.9

The present study was undertaken to determine whether total and methanol juice extracts of two Tunisian Pomegranate (Punica granatum L.) varieties (Garsi and Gabsi) protect against diarrhea as well as their effects on gastrointestinal transit (GIT) in healthy rats. In this respect, male Wistar rats were used and divided into control- and pomegranatetreated groups. The antidiarrheal activity was evaluated using the castor oil-induced diarrhea method and the GIT was assessed using charcoal meal. Our results showed that total and methanol P. granatum juice extracts produced a significant dose-dependent protection against castor oil-induced diarrhea. Pomegranate extracts and juice also decreased the GIT significantly and dose dependently. Importantly, the Garsi variety appeared to be more effective than the Gabsi variety on these two parameters. These findings suggest that pomegranate extracts have a potent antidiarrheal property in rats confirming their efficiency in the Tunisian traditional medicine.