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Mohanad Alata

Bio: Mohanad Alata is an academic researcher from King Saud University. The author has contributed to research in topics: Fuzzy logic & Fuzzy control system. The author has an hindex of 9, co-authored 23 publications receiving 369 citations. Previous affiliations of Mohanad Alata include Jordan University of Science and Technology & Concordia University.

Papers
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Journal ArticleDOI
TL;DR: The present work demonstrates the design and simulation of time controlled step sun tracking systems that include: one axis sun tracking with the tilted aperture equal to the latitude angle, equatorial two axisSun tracking and azimuth/elevation sun tracking.

121 citations

Journal Article
TL;DR: The subtractive clustering algorithm is used to provide the optimal number of clusters needed by FCM algorithm by optimizing the parameters of the subtractive clusters algorithm by an iterative search approach and then to find an optimal weighting exponent (m) for theFCM algorithm.
Abstract: Fuzzy C-means Clustering algorithm (FCM) is a method that is frequently used in pattern recognition. It has the advantage of giving good modeling results in many cases, although, it is not capable of specifying the number of clusters by itself. In FCM algorithm most researchers fix weighting exponent (m) to a conventional value of 2 which might not be the appropriate for all applications. Consequently, the main objective of this paper is to use the subtractive clustering algorithm to provide the optimal number of clusters needed by FCM algorithm by optimizing the parameters of the subtractive clustering algorithm by an iterative search approach and then to find an optimal weighting exponent (m) for the FCM algorithm. In order to get an optimal number of clusters, the iterative search approach is used to find the optimal single-output Sugenotype Fuzzy Inference System (FIS) model by optimizing the parameters of the subtractive clustering algorithm that give minimum least square error between the actual data and the Sugeno fuzzy model. Once the number of clusters is optimized, then two approaches are proposed to optimize the weighting exponent (m) in the FCM algorithm, namely, the iterative search approach and the genetic algorithms. The above mentioned approach is tested on the generated data from the original function and optimal fuzzy models are obtained with minimum error between the real data and the obtained fuzzy models. Keywords—Fuzzy clustering, Fuzzy C-Means, Genetic Algorithm, Sugeno fuzzy systems.

83 citations

Journal ArticleDOI
01 Sep 2003
TL;DR: In this paper, the authors describe the dynamic thermal behavior of thermoelectric generators and refrigerators under transient operating conditions due to the time change in the imposed current, voltage, and hot or cold temperatures.
Abstract: The objective of this work is to describe the dynamic thermal behaviour of thermoelectric generators and refrigerators. In practical situations, these devices work under transient operating conditions due to the time change in the imposed current, voltage, and hot or cold temperatures. Results for transient temperature distribution were obtained for different parameters. The coefficient of performance was obtained as a function of time for increasing current flow.

40 citations

Journal ArticleDOI
TL;DR: In this paper, the authors describe the dynamic thermal behavior of thermoelectric generators and refrigerators under the effect of the hyperbolic heat conduction model, and the coefficient of performance was obtained as a function of time for increasing current flow.
Abstract: The major objective of this work is to describe the dynamic thermal behavior of thermoelectric generators and refrigerators under the effect of the hyperbolic heat conduction model. In practical situations, these devices work under transient operating conditions due to the time change in the imposed current, voltage, and hot or cold temperatures. Results for transient temperature distributions were obtained for different parameters. The coefficient of performance was obtained as a function of time for increasing current flow.

35 citations

Journal ArticleDOI
01 Aug 2001
TL;DR: In this paper, an adaptive fuzzy control scheme for tracking a class of continuous-time plants is presented and a parameterized Sugeno fuzzy approximator is used to adaptively compensate for the plant nonlinearities.
Abstract: In this paper, an adaptive fuzzy control scheme for tracking a class of continuous-time plants is presented. A parameterized Sugeno fuzzy approximator is used to adaptively compensate for the plant nonlinearities. All parameters in the fuzzy approximator are tuned using a Lyapunov-based design. In the fuzzy approximator, first-order Sugeno consequents are used in the IF-THEN rules of the fuzzy system, which has a better approximation capability than those using constant consequents. Global boundedness of the adaptive system is established. Finally, a simulation is used to demonstrate the effectiveness of the proposed controller.

28 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, different types of sun tracking systems are reviewed and their pros and cons are discussed and the most efficient and popular sun tracking device was found to be in the form of polar-axis and azimuth/elevation types.
Abstract: Finding energy sources to satisfy the world's growing demand is one of society's foremost challenges for the next half-century. The challenge in converting sunlight to electricity via photovoltaic solar cells is dramatically reducing $/watt of delivered solar electricity. In this context the sun trackers are such devices for efficiency improvement. The diurnal and seasonal movement of earth affects the radiation intensity on the solar systems. Sun-trackers move the solar systems to compensate for these motions, keeping the best orientation relative to the sun. Although using sun-tracker is not essential, its use can boost the collected energy 10–100% in different periods of time and geographical conditions. However, it is not recommended to use tracking system for small solar panels because of high energy losses in the driving systems. It is found that the power consumption by tracking device is 2–3% of the increased energy. In this paper different types of sun-tracking systems are reviewed and their cons and pros are discussed. The most efficient and popular sun-tracking device was found to be in the form of polar-axis and azimuth/elevation types.

770 citations

Journal ArticleDOI
TL;DR: An attempt has been made to review the applications of fuzzy logic based models in renewable energy systems namely solar, wind, bio-energy, micro-grid and hybrid applications and indicates that fuzzy based models provide realistic estimates.
Abstract: In recent years, with the advent of globalization, the world is witnessing a steep rise in its energy consumption. The world is transforming itself into an industrial and knowledge society from an agricultural one which in turn makes the growth, energy intensive resulting in emissions. Energy modeling and energy planning is vital for the future economic prosperity and environmental security. Soft computing techniques such as fuzzy logic, neural networks, genetic algorithms are being adopted in energy modeling to precisely map the energy systems. In this paper, an attempt has been made to review the applications of fuzzy logic based models in renewable energy systems namely solar, wind, bio-energy, micro-grid and hybrid applications. It is found that fuzzy based models are extensively used in recent years for site assessment, for installing of photovoltaic/wind farms, power point tracking in solar photovoltaic/wind, optimization among conflicting criteria. The review indicates that fuzzy based models provide realistic estimates.

411 citations

Journal ArticleDOI
TL;DR: State-of-the-art techniques for identifying fuzzy models and designing model-based controllers are reviewed in this article and attention is paid to the role of fuzzy systems in higher levels of the control hierarchy.

397 citations

Journal ArticleDOI
20 May 2009-Sensors
TL;DR: A high level overview of the sun tracking system field is provided and some of the more significant proposals for closed-loop and open-loop types of sun tracking systems are described.
Abstract: The output power produced by high-concentration solar thermal and photovoltaic systems is directly related to the amount of solar energy acquired by the system, and it is therefore necessary to track the sun's position with a high degree of accuracy. Many systems have been proposed to facilitate this task over the past 20 years. Accordingly, this paper commences by providing a high level overview of the sun tracking system field and then describes some of the more significant proposals for closed-loop and open-loop types of sun tracking systems.

236 citations

Journal ArticleDOI
TL;DR: In this paper, a framework for mapping potential flooding areas incorporating geographic information systems (GIS), fuzzy logic and clustering techniques, and multi-criteria evaluation methods is presented.
Abstract: A fundamental component of the European natural disaster management policy is the detection of potential flood-prone areas, which is directly connected to the European Directive (2007/60). This study presents a framework for mapping potential flooding areas incorporating geographic information systems (GIS), fuzzy logic and clustering techniques, and multi-criteria evaluation methods. Factors are divided in different groups which do not have the same level of trade off. These groups are related to geophysical, morphological, climatological/meteorological and hydrological characteristics of the basin as well as to anthropogenic land use. GIS and numerical simulation are used for geographic data acquisition and processing. The selected factor maps are considered in order to estimate the spatial distribution of the potential flood prone areas. Using these maps, the study area is classified into five categories of flood vulnerable areas. The Multi-Criteria Analysis (MCA) techniques consist of the crisp and fuzzy analytical hierarchy processes (AHP) and are enhanced with different standardization methods. The classification is based on different clustering techniques and it is applied in two approaches. In the first approach, all criteria are normalized before the MCA process and then, the clustering techniques are applied to derive the final flood prone area maps. In the second approach, the criteria are clustered before and after the MCA process for the potential flood prone area mapping. The methodology is demonstrated in Xerias River watershed, Thessaly region, Greece. Xerias River floodplain was repeatedly flooded in the last few years. These floods had major impacts on agricultural areas, transportation networks and infrastructure. Historical flood inundation data has been used for the validation of the methodology. Results show that multiple MCA techniques should be taken into account in initial low-cost detection surveys of flood-prone areas and/or in preliminary analysis of flood hazard mapping.

214 citations