Modeling and control of microgrid: An overview     

M.S. Mahmoud  S. Azher Hussain  M.A. Abido 《Journal of The Franklin Institute》2014

A microgrid (MG) is a building block of future smart grid, it can be defined as a network of low voltage power generating units, storage devices and loads. System of systems (SoS) is another concept involving large scale integration of various systems. In this paper, we provide an overview of recent developments in modeling and control methods of microgrid as well as presenting the reason towards incorporating MG into the existing grid. Various SoS control strategies when applied to MG are discussed.  相似文献   

School Leaders’ and Teachers’ Perceptions of Learning Disabilities: Implications for Support in Inclusive Schools in the Sultanate of Oman     

Mahmoud Mohamed Emam  Hussain Alkharusi 《International Journal of Disability, Development & Education》2018,65(5):475-492

The study examined school leaders’ and teachers’ perceptions of Learning Disabilities (LDs) in Key Stage1 Schools in a sample drawn from schools in Muscat, the capital city of Oman. A sample of 175 school leaders and 175 teachers completed The Survey on Learning Disabilities (SLD), an instrument developed to explore beliefs and perceptions of the causes of LDs. A principal component analysis indicated that six factors underlie perceptions of LDs: The governmental formal educational system, repertoire of teachers’ skills and school support, familial and cultural background, students, academic curriculum, and social change. Multivariate analyses showed that school leaders perceive more strongly than teachers that the governmental formal educational system and academic curriculum as main causal factors for LDs. Implications for support of students with LDs in inclusive settings in Oman are discussed.  相似文献   

Emotional and behavioural difficulties among middle school students in Oman: an examination of prevalence rate and gender differences     

Mahmoud Mohamed Emam  Ali Mahdi Kazem  Abdulqawi Salim Al-Zubaidy 《Emotional and Behavioural Difficulties》2016,21(3):314-328

Children with emotional and behavioural difficulties (EBDs) began to receive considerable attention in several countries in the Middle East and North Africa region including Oman. In the Omani context, there is lack of valid assessment instruments which can be used to obtain information on EBDs in schools. The current study used the Arabic self-report version of the Strengths and Difficulties Questionnaire (A-SDQ) to examine EBDs in a sample of middle school students. 816 middle school students from both genders, who were randomly selected from different schools in two big cities in Oman, filled out the A-SDQ. Results provided initial evidence of good psychometric properties of the A-SDQ reflecting that it can be a valid tool for use in schools in Oman. Further, the participants reported moderate to high rates of EBDs as measured by the different subscales of the A-SDQ. Significant gender differences were found in students self-report of EBDs. Compared to boys, girls reported more emotional symptoms, less conduct and peer problems. Implications of the study findings for the identification of students with EBDs in schools in Oman are presented.  相似文献   

Competing Strategies to Balance the Budgets of Publicly Funded Higher Education Institutions     

Mahmoud Yousef Askari 《Interchange》2017,48(4):377-386

This paper compares and contrasts different strategies to balance academic institutions’ operating budgets. Some strategies use economic theory to recommend a budgeting technique, others use management methods to cut cost, and some strategies use a management accounting approach to reach a balanced budget. Through the use of a simplified numerical example of a breakeven analysis model, this paper argues that excess capacity and high enrolment levels are needed for some proposed budget balancing recommendations to work. It also argues that low enrolment institutions and academic units need to be subsidized to keep their doors open.  相似文献   

New results on linear parameter-varying time-delay systems     

Magdi S. Mahmoud 《Journal of The Franklin Institute》2004,341(7):675-703

A class of linear parameter-varying time-delay systems where the state-space matrices depend on time-varying parameters and the time-delay is unknown but bounded is considered. Both notions of quadratic stability (using a single quadratic Lyapunov-Krasovskii function) and affine quadratic stability (using parameter-dependent Lyapunov-Krasovskii functions) are investigated. LMI-based delay-independent and delay-dependent conditions are derived for stability testing. Then, state-feedback controllers are designed which guarantee quadratic stability and an induced L₂-norm bound. We use a parameter-independent quadratic Lyapunov-Krasovskii function for the case of dynamic output feedback control to develop LMI-based solvability conditions which are evaluated at the extreme points of the admissible parameter set. Numerical examples are presented.  相似文献   

Counseling and guidance in the Kingdom of Saudi Arabia     

Mahmoud Abdullah Saleh 《International journal for the advancement of counseling》1987,10(4):277-286

The Kingdom of Saudi Arabia is striving to develop a counseling and guidance program to serve its nation. This study focuses on the educational goals of Saudi Arabia in general and the goals and objectives of the counseling and guidance program specifically. The study examines the development of the counseling and guidance program, the philosophical assumptions of the program, the administration of the program, and the training of the school counselor.  相似文献   

Library Anxiety among Undergraduate Students: A Comparative Study on Egypt and Saudi Arabia     

Ahmed Maher Khafaga Shehata  Mohammed Fathy Mahmoud Elgllab 《The Journal of Academic Librarianship》2019,45(4):386-393

The purpose of this paper is to report the findings of a study of library anxiety among a group of Arab students in Saudi Arabia and Egypt. The paper also investigated the factors that affect the students' level of anxiety while using academic libraries. The study tried to compare the difference in the level of anxiety in the two countries using a scale (LLPB) developed by the researchers which fit the culture in the Arab region. The study adopted a mixed methods approach. Semi-structured interviews were conducted with several students in Saudi Arabia and Egypt to determine the main factors that lead to having a level of anxiety in the libraries. In the second stage, a questionnaire was sent to students to measure what factors have a greater impact on the level of anxiety. The data showed that Egyptian students are more anxious about using the libraries than the Saudi students. The results also indicated that there is a need to train students on how to use the libraries and also change students' perception regarding the library to reduce the level of anxiety. This study was conducted in Egypt and Saudi Arabia the level of library anxiety and the factors that may affect the students may vary in other countries.  相似文献   

Different effects of L-arginine on morphine tolerance in sham and ovariectomized female mice     

Karami R  Hosseini M  Khodabandehloo F  Khatami L  Taiarani Z 《Journal of Zhejiang University. Science. B》2011,12(12):1016-1023

Objective  

The roles of gonadal hormones and nitric oxide (NO) on the analgesic effects of morphine, tolerance to morphine, and their interactions have been widely investigated. In the present study, the effect of l-arginine (an NO precursor) on morphine tolerance in sham and ovariectomized (OVX) female mice was investigated.  相似文献   

Anatomical sciences: A foundation for a solid learning experience in dental technology and dental prosthetics          下载免费PDF全文

Mahmoud M. Bakr  C. Mark Thompson  Magdalena Massadiq 《Anatomical sciences education》2017,10(4):395-404

Basic science courses are extremely important as a foundation for scaffolding knowledge and then applying it in future courses, clinical situations as well as in a professional career. Anatomical sciences, which include tooth morphology, oral histology, oral embryology, and head and neck anatomy form a core part of the preclinical courses in dental technology programs. In this article, the importance and relevance of anatomical sciences to dental personnel with no direct contact with patients (dental technicians) and limited discipline related contact with patients (dental prosthetists) is highlighted. Some light is shed on the role of anatomical sciences in the pedagogical framework and its significance in the educational process and interprofessional learning of dental technicians and prosthetists using oral biology as an example in the dental curriculum. To conclude, anatomical sciences allow dental technicians and prosthetists to a gain a better insight of how tissues function, leading to a better understanding of diagnosis, comprehensive treatment planning and referrals if needed. Patient communication and satisfaction also increases as a result of this deep understanding of oral tissues. Anatomical sciences bridge the gap between basic science, preclinical, and clinical courses, which leads to a holistic approach in patient management. Finally, treatment outcomes are positively affected due to the appreciation of the macro and micro structure of oral tissues. Anat Sci Educ 10: 395–404. © 2016 American Association of Anatomists.  相似文献   

Robust cooperative control for a group of mobile robots with quantized information exchange     

Jawhar Ghommam  Magdi S. Mahmoud  Maarouf Saad 《Journal of The Franklin Institute》2013

In this paper we investigate the cooperative tracking control problem with quantized time delay information exchange for a group of wheeled mobile robots networked through a connected graph modeling the underlying communication topology. A cooperative controller is proposed using a combination of backstepping technique, graph theory and neural network radial basis functions. We show, using the small gain theorem, that the states of each mobile robot in the group converge to and remain inside a tube centered around its assigned trajectory to form a desired geometric pattern whose centroid is assumed to move along a predefined trajectory. Experimental results on a group of three mobile robots forming a triangular shape are presented to demonstrate the good performance of the proposed cooperative controller.  相似文献