Preferred Language
Articles
/
joe-676
Variable Structure Control Design for a Magnetic Levitation System
...Show More Authors

In this paper the variable structure control theory is utilized to derive a discontinuous controller to the magnetic levitation system. The magnetic levitation system model is considered uncertain, which subjected to the uncertainty in system parameters, also it is open-loop unstable and strongly nonlinear. The proposed variable structure control to magnetic levitation system is proved, and the area of attraction is determined. Additionally, the chattering, which induced due to the discontinuity in control law, is attenuated by using a non-smooth approximate. With this approximation the resulted controller is a continuous variable structure controller with a determined steady state error according to the selected control parameters. Finally the ability and the effectiveness of the proposed continuous variable structure controller to the magnetic levitation system are verified via numerical simulations. When state initiated inside the area of attraction, the results show that the ball position can be directed to follow various desired positions, with steady state error not exceeding .  

 

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Wed Jun 10 2009
Journal Name
Iraqi Journal Of Laser
The performance of a passively Q-switched Cr:YAG4+ in an end- pumped laser system
...Show More Authors

A characteristic study of a passively Q-switched diode pumped solid state laser system is presented in this work. For laser a comparison study for the theoretically calculated results with a simulation results using a software which calculates the Q-switched solid state laser parameters was such as energy, peak power and pulse width were performed. There was a good agreement between our theoretical calculations and the simulation values.

View Publication Preview PDF
Publication Date
Mon Dec 30 2013
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
A Study of Water Flux through Forward Osmosis Membrane Using Brine\Fresh Water System
...Show More Authors

The present work aims to improve the flux of forward osmosis with the use of Thin Film Composite membrane by reducing the effect of polarization on draw solution (brine solution) side.This study was conducted in two parts. The first is under the effect of polarization in which the flux and the water permeability coefficient (A) were calculated. In the second part of the study the experiments were repeated using a circulating pump at various speeds to make turbulence and reduce the effect of polarization on the brine solution side.
A model capable of predicting water permeability coefficient has been derived, and this is given by the following equations:
Z=Z+C.R.T/9.8(d2/D2+1) [Exp. [-9.8(d

... Show More
View Publication Preview PDF
Publication Date
Sun Mar 17 2019
Journal Name
Baghdad Science Journal
A Study on the Accuracy of Prediction in Recommendation System Based on Similarity Measures
...Show More Authors

Recommender Systems are tools to understand the huge amount of data available in the internet world. Collaborative filtering (CF) is one of the most knowledge discovery methods used positively in recommendation system. Memory collaborative filtering emphasizes on using facts about present users to predict new things for the target user. Similarity measures are the core operations in collaborative filtering and the prediction accuracy is mostly dependent on similarity calculations. In this study, a combination of weighted parameters and traditional similarity measures are conducted to calculate relationship among users over Movie Lens data set rating matrix. The advantages and disadvantages of each measure are spotted. From the study, a n

... Show More
View Publication Preview PDF
Scopus (17)
Crossref (2)
Scopus Clarivate Crossref
Publication Date
Sat Aug 01 2015
Journal Name
Journal Of Engineering
A Real-Time Fuzzy Load Flow and Contingency Analysis Based on Gaussian Distribution System
...Show More Authors

Fuzzy logic is used to solve the load flow and contingency analysis problems, so decreasing computing time and its the best selection instead of the traditional methods. The proposed  method is very accurate with outstanding computation time, which made the fuzzy load flow (FLF) suitable for real time application for small- as well as large-scale power systems. In addition that, the FLF efficiently able to solve load flow problem of ill-conditioned power systems and contingency analysis. The FLF method using Gaussian membership function requires less number of iterations and less computing time than that required in the FLF method using triangular membership function. Using sparsity technique for the input Ybus sparse matrix data gi

... Show More
View Publication Preview PDF
Publication Date
Sun Jun 22 2025
Journal Name
Al–bahith Al–a'alami
DICTION (IN ARAB SATELLITE CHANNELS) A SIGNAL SYSTEM : (study of written And oral patterns)
...Show More Authors

Communication has seen a big advancement through ages; concepts, procedures and technologies, it has also seen a similar advancement of language. What unites language and media is the fact that each one of them guides and contributes to the other; media exists and results from language and from the other sign systems, and what strengthens this connection is the symbolic language system, as media helps it by providing knowledge and information. The change that occurred through time must leave a significant trace in the media, for example Diction, which has changed concerning development and growth, also the ways and mediums of media have become manifold and widespread. This change affected the recipient whether it was a reader, listener o

... Show More
View Publication Preview PDF
Publication Date
Sun Sep 11 2022
Journal Name
Mathematics
Modeling and Analysis of the Influence of Fear on a Harvested Food Web System
...Show More Authors

The food web is a crucial conceptual tool for understanding the dynamics of energy transfer in an ecosystem, as well as the feeding relationships among species within a community. It also reveals species interactions and community structure. As a result, an ecological food web system with two predators competing for prey while experiencing fear was developed and studied. The properties of the solution of the system were determined, and all potential equilibrium points were identified. The dynamic behavior in their immediate surroundings was examined both locally and globally. The system’s persistence demands were calculated, and all conceivable forms of local bifurcations were investigated. With the aid of MATLAB, a numerical simu

... Show More
View Publication
Scopus (10)
Crossref (7)
Scopus Clarivate Crossref
Publication Date
Mon Nov 01 2021
Journal Name
Energies
Solidification Enhancement in a Triple-Tube Latent Heat Energy Storage System Using Twisted Fins
...Show More Authors

This work evaluates the influence of combining twisted fins in a triple-tube heat exchanger utilised for latent heat thermal energy storage (LHTES) in three-dimensional numerical simulation and comparing the outcome with the cases of the straight fins and no fins. The phase change material (PCM) is in the annulus between the inner and the outer tube, these tubes include a cold fluid that flows in the counter current path, to solidify the PCM and release the heat storage energy. The performance of the unit was assessed based on the liquid fraction and temperature profiles as well as solidification and the energy storage rate. This study aims to find suitable and efficient fins number and the optimum values of the Re and the inlet tem

... Show More
View Publication
Scopus (38)
Crossref (37)
Scopus Clarivate Crossref
Publication Date
Mon Dec 07 2020
Journal Name
Iranian Journal Of Parasitology
Serum levels of il-12 and il-23 in breast cancer patients infected with toxoplasma gondii: A case-control study
...Show More Authors

Scopus (2)
Scopus
Publication Date
Sun Jul 02 2006
Journal Name
Journal Of The Faculty Of Medicine Baghdad
a placebo control study of the effect of nigella sativa fixed oil on the healing rate of recurrent aphthous ulceration
...Show More Authors

View Publication
Crossref
Publication Date
Wed Mar 23 2022
Journal Name
Journal Of Educational And Psychological Researches
Mental wandering and its relationship to attention control among university students
...Show More Authors

Research summary: The current research aims to identify:

1-Mental wandering among university students 2- Attentioncontrol among universitey students. 3- The relationship between mental wandering and attention control among university students. 4- The difference in the relationship among university students: accoerding to a- the gender variable (males - females) b- according to the specialization variable) Scientific-human), and the results of the current research reached the following: 1- University students have mental wandering associated with the task, and mental wandering that is not related to the task. 2- University students have attentive control 3- There is no relationship between mental wandering associated with task and

... Show More
View Publication Preview PDF