Khedmati M.R.,Amirkabir University of Technology |
Bayatfar A.,Azad University |
Rigo P.,University of Liege
Marine Structures | Year: 2010
This paper presents the results of complementary numerical study done in the continuation of the activities carried out by the Committee III.1 " Ultimate Strength" of ISSC'2003 (Ref.  ).The main focus of the paper concerns the post-buckling behaviour and strength characteristics of the aluminium multi-stiffened panels under combined axial compression and lateral pressure.The finite element model proposed by the Committee III.1 " Ultimate Strength" of ISSC'2003 is used in the present investigation. Material is aluminium alloy AA6082-T6 and the multi-stiffened panel is a triple-span structure. Stiffeners are of either extruded or non-extruded angle-bar profiles. An initial deflection is imposed on the model in a procedure similar to that applied by the Committee III.1. General purpose finite element code ANSYS is used for non-linear elastic-plastic analyses.Main objectives are to study the influence of initial deflections and also HAZ on the post-buckling behaviour and collapse characteristics of aluminium stiffened panels under combined axial compression and lateral pressure. Different values of lateral pressure are exerted on the model in a systematic manner to simulate various levels of lateral pressure loading on multi-stiffened aluminium panels used in the construction of high-speed crafts. © 2009 Elsevier Ltd.
Shafiei S.,Azad University |
Salim R.A.,Curtin University Australia
Energy Policy | Year: 2014
This paper attempts to explore the determinants of CO2 emissions using the STIRPAT model and data from 1980 to 2011 for OECD countries. The empirical results show that non-renewable energy consumption increases CO2 emissions, whereas renewable energy consumption decreases CO2 emissions. Further, the results support the existence of an environmental Kuznets curve between urbanisation and CO2 emissions, implying that at higher levels of urbanisation, the environmental impact decreases. Therefore, the overall evidence suggests that policy makers should focus on urban planning as well as clean energy development to make substantial contributions to both reducing non-renewable energy use and mitigating climate change. © 2013.
Eidiani M.,Azad University
International Review of Electrical Engineering | Year: 2010
Voltage instability and collapse has been the subject of an increasing body of research over the past few years. In this paper, we proposed a new method of assessing static voltage stability in transmission and distribution networks. The proposed method (PM) is fast, accurate and robust. The expanded Newton-Raphson-Seydel (NRS) and Down-Hill (DH) algorithms are used in PM. Moreover, the elimination of the trigonometric terms in power flow equations and Jacobian matrix, will improve the convergence of PM algorithm. Standard CPF, CPF-GMRES and expanded NRS methods are compared to PM. These algorithms are tested on 350 bus transmission and 1316 bus distribution networks. © 2010 Praise Worthy Prize S.r.l. - All rights reserved.
Vatankhah M.,Azad University |
Asadpour V.,Sadjad Institute of Higher Educations |
Fazel-Rezai R.,University of North Dakota
Applied Soft Computing Journal | Year: 2013
Diagnosing pain mechanisms is one of the main approaches to improve clinical treatments. Especially, the detection of existence and/or level of pain can be vital when verbal information is not present for instant for neonates, disabled persons, anesthetized patients and also animals. Various researches have been performed to locate and classify pain, however, no consistent result has been achieved. The aim of this study is to show a strict relation between electroencephalogram (EEG) signal features and perceptual pain levels and to clarify the relation of classified signal to pain origin. Cortical regions on scalp were assigned based on an evolutional method for optimized alignment of electrodes that improve the clinical monitoring results. The EEG signals were recorded during relax condition and variety of pain conditions. Specific spectral features which are studied to show consistency with dynamical characteristic of EEG signals were combined with non-linear features including approximate entropy and Lyapunov exponent to provide the feature vector. Evolutionary optimization method was used to reduce the features space dimension and computational costs. A hybrid adaptive network fuzzy inference system (ANFIS) and support vector machine (SVM) scheme was used for classification of pain levels. ANFIS optimizer is used to fine tune the non-linear alignment of kernels of SVM. The results show that pain levels can be differentiated with high accuracy and robustness even for few recording electrodes. This research verifies the hypothesis that electrical variations of brain patterns can be used for determination of pain levels. The proposed classification method provided up to 95% accuracy. © 2012 Elsevier B.V. All rights reserved.
Sabahi F.,Azad University
2011 IEEE 3rd International Conference on Communication Software and Networks, ICCSN 2011 | Year: 2011
Cloud computing is one of today's most exciting technology because of its cost-reducing, flexibility, and scalability. With the fast growing of cloud computing technology, Data security becomes more and more important in it. In evaluating whether to move to cloud computing, it is important to compare benefits and also risks of it. Thus, security and other existed issues in the cloud cause cloud clients need more time to think about moving to cloud environments. But Security-related topics is one of the most arguable issues in the cloud computing which caused several enterprises looks to this technology uncertainly and move toward it warily. In this paper I try to summarize cloud computing RAS (Reliability, Availability, and Security) issues and also clarify available solution for some of them. In this paper I try to summarize virtualization level of cloud computing security in detailed view. © 2011 IEEE.