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Author

Majed Alowaidi

Other affiliations: University of Ottawa
Bio: Majed Alowaidi is an academic researcher from Majmaah University. The author has contributed to research in topics: Computer science & Cloud computing. The author has an hindex of 5, co-authored 20 publications receiving 79 citations. Previous affiliations of Majed Alowaidi include University of Ottawa.

Papers
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Journal ArticleDOI
TL;DR: An analytic hierarchy process (AHP) inspired methodology is proposed for PQ assessment of distorted distribution power systems under the presence of renewable-based DGs and validates the efficacy of the presented approach in assessing the overall PQ performance of each of the buses and the entire DN.
Abstract: The proliferation of not only power electronics supported consumption technologies but also the expansion of the renewable-based distributed generation (DG) systems has given rise to severe power quality (PQ) phenomena in consort with the offered technical, economic and environmental benefits under deregulated environment. The forthcoming complexity of distribution power networks caused by incorporation of a large number of DG units in deregulated electricity market unquestionably makes PQ assessment procedure a quite cumbersome one. In present work, an analytic hierarchy process (AHP) inspired methodology is proposed for PQ assessment of distorted distribution power systems under the presence of renewable-based DGs. The proposed PQ assessment approach is based on formulating a unified power quality index (UPQI) for assessing the overall PQ performance of individual buses of the network along with the entire distribution network (DN) considered taking four PQ phenomena, viz. voltage harmonics, voltage sags, voltage unbalance and steady-state voltage profile at each bus into account. t. The application significance of the presented methodology is established by utilizing it on an IEEE 13 bus test distribution system modified through incorporating the nonlinear loads and DG systems based on three types of RES namely, photovoltaic (PV), wind and fuel cell, in MATLAB/Simulink environment. The results achieved validates the efficacy of the presented approach in assessing the overall PQ performance of each of the buses and the entire DN along with benchmarking it with respect to the threshold level of unity. Based on obtained results, also the comparative analysis is performed among PQ performances of DN with selected three RES based DGs. Moreover, the impact of the employing the custom power devices (CPDs) as well as excessive penetration level of renewable energy over PQ performance of distribution network, are also investigated by the application of the formulated index.

46 citations

Journal ArticleDOI
TL;DR: This paper aims to resolve issues and provide the countermeasures relating to security issues in clouds based web applications and observed most of the vulnerabilities identified during the scanning are related to security due to mis-configurations of web servers.
Abstract: The Cloud computing is a powerful tool to optimize the cost in terms of hardware, controllable, utility to sharing the data, due to abovementioned features most of the organization switching their applications and services on the cloud. Cloud services offer secure and scalable services, but there is always some security problem when data have transmitted from a central storage server to a different cloud, personal and private data commitment increase risk of data confidentiality, integrity, availability, and authentication before one choose a vendor in the cloud or choose the cloud and move services in the cloud. This paper aims to resolve issues and provide the countermeasures relating to security issues in clouds based web applications. The vulnerability scores, its impact on confidentiality, integrity, availability, access complexity, and risk on assets calculated, and it observed most of the vulnerabilities identified during the scanning are related to security due to mis-configurations of web servers. The results analyzed for the vulnerability scores, vulnerabilities impact on confidentiality, integrity, availability, access complexity, and risk are analyzed description, and risk assessment. The countermeasures for each vulnerability based on the experimental results discussed.

30 citations

Journal ArticleDOI
TL;DR: In this paper, the authors examined and compared two control techniques for extracting full power from the solar energy system, namely the classical perturbation and observation (P&O) method and the intelligent solution particle swarm optimization (PSO).
Abstract: A photovoltaic-powered electric vehicle is a complex system that necessitates the use of a high-performance control algorithm. This paper aims to boost the performance of a photovoltaic system by employing a suitable algorithm to control the power interface. The main goal is to find an effective and optimal control law that will enable the photovoltaic generator (GPV) to generate the maximum amount of power possible. The main facts dealt with in this article are the mathematical simulation of the photovoltaic system, its function, and its characteristics, considering the synthesis of the step-up converter and the analysis of the maximum power point tracking algorithm. This study examines and compares two control techniques for extracting full power from the solar energy system. These two techniques are the classical “perturbation and observation” (P&O) method and the intelligent solution “particle swarm optimization (PSO) method.” The PSO solution is tested for two versions: the online PSO version and the table PSO version. The Simulink/MATLAB tool is used for simulation and comparative experiments based on the performance metrics provided. The study revealed that smart technology delivers improved efficiency than the classic edition.

18 citations

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a hybrid scheduling algorithm (HS) which is based on the genetic algorithm (GA) and Flower Pollination based Algorithm (FPA) for cloud environments, and the simulation results revealed that HS has demonstrated maximum resource utilization with minimum energy consumption in less completion time for the execution of the tasks as compared to the existing scheduling algorithms in both environments.
Abstract: The main intent of the cloud computing to provide utilities to the demands of the users that are booming day by day. To meet the requirements, existing scheduling algorithms focus on the improving the performance and neglecting the energy consumed to fulfill those demands. Hence, we propose a new Hybrid Scheduling Algorithm (HS) which is based on the Genetic Algorithm (GA) and Flower Pollination based Algorithm (FPA) for cloud environments. The proposed scheduling algorithm has surpassed in terms of performance across various parameters, i.e. completion time, resource utilization, cost of computation, and energy consumption for both cloud environments than the existing scheduling algorithms (GA and FPA). The simulation results revealed that HS has demonstrated maximum resource utilization with minimum energy consumption in less completion time for the execution of the tasks as compared to the existing scheduling algorithms in both environments. The simulation results have shown that HS has utilization of the resources, 36% better than GA and 16% better than FPA in homogeneous environment whereas in heterogenous environment, HS has performed 12% better than GA and 3.8% better than FPA. The performance of HS has an improvement of 2.6% from FPA and 6.9% from the GA for completion time in homogeneous environment whereas the completion time of the HS is reduced by 17.8% from FPA and 33.7% from GA in heterogeneous environment. For energy consumption, HS has improved 22% than FPA and 11% from GA in the homogeneous environment and HS is 4% better than FPA and 14% from GA in heterogeneous environment.

18 citations

Journal ArticleDOI
TL;DR: In this article, a 3-phase shunt active power filter (SAPF) is designed for compensation of harmonics resulted in the feeder current owing to the customer side nonlinearity.
Abstract: Shunt active power filter (SAPF) belongs to the class of custom power devices (CPDs) and offers compensation to harmonics originated owing to customer side nonlinear loads, reactive power and unbalance in the distribution power networks functioning in current control mode (CCM). The performance of a SAPF as a harmonic compensator entirely relies on the control technique i.e. the precise detection of the harmonic current components of load that are necessary to be compensated. In the present work, a 3-phase SAPF, inspired by a Lyapunov function based control approach, has been designed for compensation of harmonics resulted in the feeder current owing to the customer side nonlinearity. A control law is determined in the proposed strategy which makes the derivative of the Lyapunov function consistently a negative one for an entire set of stable states. The DC-link capacitor voltage is regulated at constant reference through the proportional-integral (PI) controller. In this method rating of the shunt active power filter is considerably reduced than the other two broadly employed conventional methods. Furthermore, the harmonic compensation efficacy of the proposed Lyapunov function based SAPF is compared with the one based on other two conventional approaches under four different system scenarios namely a simple nonlinear load with and without utility side voltage distortion, a modified IEEE 13 bus test distribution system loaded with a 3-phase chopper fed direct current (DC) motor drive at a single bus and last especially for increasing the harmonic-constrained penetration level of renewable energy. Results obtained through simulation performed in MATLAB/Simulink shows that total harmonic distortion (THD) of source current and dynamic, as well as steady-state performance with Lyapunov function based controller, is significantly improved than the other two conventional methods. Also, the robust compensation performance of the SAPF empowers it to deal with the high penetration of renewable energy.

18 citations


Cited by
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01 Jan 2013
TL;DR: From the experience of several industrial trials on smart grid with communication infrastructures, it is expected that the traditional carbon fuel based power plants can cooperate with emerging distributed renewable energy such as wind, solar, etc, to reduce the carbon fuel consumption and consequent green house gas such as carbon dioxide emission.
Abstract: A communication infrastructure is an essential part to the success of the emerging smart grid. A scalable and pervasive communication infrastructure is crucial in both construction and operation of a smart grid. In this paper, we present the background and motivation of communication infrastructures in smart grid systems. We also summarize major requirements that smart grid communications must meet. From the experience of several industrial trials on smart grid with communication infrastructures, we expect that the traditional carbon fuel based power plants can cooperate with emerging distributed renewable energy such as wind, solar, etc, to reduce the carbon fuel consumption and consequent green house gas such as carbon dioxide emission. The consumers can minimize their expense on energy by adjusting their intelligent home appliance operations to avoid the peak hours and utilize the renewable energy instead. We further explore the challenges for a communication infrastructure as the part of a complex smart grid system. Since a smart grid system might have over millions of consumers and devices, the demand of its reliability and security is extremely critical. Through a communication infrastructure, a smart grid can improve power reliability and quality to eliminate electricity blackout. Security is a challenging issue since the on-going smart grid systems facing increasing vulnerabilities as more and more automation, remote monitoring/controlling and supervision entities are interconnected.

1,036 citations

Journal ArticleDOI
TL;DR: Pradeep Sinha introduces OSF DCE (the Open Systems Foundation’s Distributed Computing Environement), which contains almost half the key technologies presented in this book.
Abstract: Today’s typical computing environment has changed from mainframe systems to small computing systems that often cooperate via communication networks. Distributed Operating Systems: Concepts and Design addresses the organization and principles of distributed computing systems. Although it does not concentrate on any particular operating system or hardware, it introduces the major concepts of distributed operating systems without requiring that readers know all the theoretical or mathematical fundamentals. Each chapter covers a special issue of distributed computing systems and concludes with a summary, exercises, and a bibliography (with pointers to other bibliographies on the Internet). Pradeep Sinha encourages readers to use the exercises to test their understanding of the text and stimulate further investigations. In Chapter 1, Sinha focuses on hardware, declaring that distributed computing systems based on networks of loosely coupled processing nodes are different from “true distributed systems”-distributed computing systems using distributed operating systems. After a short historical review, he presents major distributed computing system models and reviews issues to consider when designing a distributed operating system. Finally, he introduces OSF DCE (the Open Systems Foundation’s Distributed Computing Environement), which contains almost half the key technologies presented in this book. Chapter 2 briefly introduces computer networks and the state of the art in networking technology. It emphasizes models and protocols of communication in distributed networks and discusses internetworking and ATM technologies. The next three chapters cover the elements of interprocess communication used in distributed environments. Chapter 3 introduces message passing, the basic mechanism of information sharing between two or more processes on different computers. A case study of 4.3 BSD Unix interprocess communication mechanisms illustrates the relevant aspects of message passing. Chapter 4 discusses remote procedure calls, a special implementation of the general message-passing model and concludes with a case study of RPC implementations-SUN RPC and DCE W C . Chapter 5 describes distributed shared memory. It clearly presents how shared memory interprocess communication works differently on tightly or loosely coupled multiprocessor systems, and it introduces a distributed shared-virtual-memory model. Sinha discusses important issues concerning data management such as consistency and granularity, thrashing, and replacement strategies. Chapter 6 covers synchronization, a major problem of concurrent computing created when distributed processes cooperatively or competitively share distributed resources. Issues discussed include deadlock, mutual exclusion, clock synchronization, and event ordering. The next two chapters address in more detail the management of computing resources, from different points of view. Chapter 7 deals with the allocation of processing nodes to processes-that is, task assignment, load balancing and load sharing. Sinha describes each of these three approaches in detail and compares it to the others. Chapter 8 adopts a different viewpoint; it discusses how to tile processes and distribute them efficiently on a network of processing nodes. Topics of interest are threading and process migration. Chapter 9 deals with file systems in distributed environments. It defines terms, describes 10 desirable features of an ideal distributed file system, and discusses file models, file-accessing, file-sharing, file-caching, file-replication, and transactions. The chapter concludes with a case study of the DCE Distributed File Service model. Chapter 10 describes the problems of naming and locating objects in a distributed environment. This is the first chapter that explicitly associates processes, files, devices, and processing nodes with an abstract object model. Sinha introduces terminologies, naming concepts, and desirable features for naming systems. H e explains system-oriented and human-oriented naming conventions, derived name spaces, and how these are related, as well as name resolution and name cache. Chapter 10 concludes with a case study of the DCE Directory Service. Chapter 11 illustrates several aspects and problems of internal security-for example,

78 citations

Journal ArticleDOI
TL;DR: The optimization efficiency and superiority of the proposed multi-objective firefly algorithm based hosting capacity enhancement approach is validated by comparing the results with those obtained by popular multi-Objective PSO (MOPSO) and non-dominated sorting genetic algorithm (NSGA-II) under similar objectives.

41 citations

Journal ArticleDOI
14 Sep 2021-Energies
TL;DR: An intelligent control strategy is proposed in this paper which suggests the Optimum Power Quality Enhancement (OPQE) of grid-connected hybrid power systems with solar photovoltaic, wind turbines, and battery storage and found the proposed approach is efficient.
Abstract: An intelligent control strategy is proposed in this paper which suggests the Optimum Power Quality Enhancement (OPQE) of grid-connected hybrid power systems with solar photovoltaic, wind turbines, and battery storage. Unified Power Quality Conditioner with Active and Reactive power (UPQC-PQ) is designed with Atom Search Optimization (ASO) based Fractional-order Proportional Integral Derivative (FOPID) controller in the proposed Hybrid Renewable Energy Sources (HRES) system. The main aim is to regulate voltage while reducing power loss and reducing Total Harmonic Distortion (THD). UPQC-PQ is used to mitigate the Power Quality (PQ) problems such as sag, swell, interruptions, real power, reactive power and THD reductions related to voltage/current by using ASO based FOPID controller. The developed technique is demonstrated in various modes: simultaneous to improve PQ reinforcement and RES power injection, PRES > 0, PRES = 0. The results are then compared to those obtained using previous literature methods such as PI controller, GSA, BBO, GWO, ESA, RFA, and GA and found the proposed approach is efficient. The MATLAB/Simulink work framework is used to create the model.

34 citations