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Design of MMIC oscillators using GaAs 0.2 μm PHEMT technology

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Journal of Zhejiang university-Science C(Computers and Electronics) 2012年第10期13卷 793-798页

作者： Neda KAZEMY NAJAFABADI Sare NEMATI Massoud DOUSTI department of electrical Engineering Arak BranchIslamic Azad UniversityArakIran department of electrical Engineering Science and Research BranchIslamic Azad UniversityTehranIran

We propose a feedback type oscillator and two negative resistance *** microwave oscillators have been designed in the S band frequency.A relatively symmetric resonator is used in the feedback type *** first negative resistance oscillator uses a simple lumped element resonator which is substituted by a microstrip resonator in the second oscillator to improve *** negative resistance oscillator produces 4.207 dBm and 7.124 dBm output power with the lumped element resonator and microstrip resonator respectively,and the feedback type oscillator produces ?10.707 dBm output *** feedback type oscillator operates at 3 GHz with phase noise levels at-83.30 dBc/Hz and-103.3 dBc/Hz at 100 kHz and 1 MHz offset frequencies *** phase noise levels of the negative resistance oscillator with the lumped element resonator are-94.64 dBc/Hz and-116 dBc/Hz at 100 kHz and 1 MHz offset frequencies respectively,at an oscillation frequency of 3.053 *** the microstrip resonator the phase noise levels are-99.49 dBc/Hz and-119.641 dBc/Hz at 100 kHz and 1 MHz offset frequencies respectively,at an oscillation frequency of 3.072 *** results showed that both the output power and the phase noise of the negative resistance oscillators were better than those of the feedback type oscillator.

关键词： Microwave oscillator Feedback type Negative resistance Resonator Advanced design system software

High-Performance Flow Classification of Big Data Using Hybrid CPU-GPU Clusters of Cloud Environments

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Tsinghua Science and Technology 2024年第4期29卷 1118-1137页

作者： Azam Fazel-Najafabadi Mahdi Abbasi Hani H.Attar Ayman Amer Amir Taherkordi azad Shokrollahi Mohammad R.Khosravi Ahmed A.Solyman department of Computer Engineering Faculty of EngineeringBu-Ali Sina UniversityHamedan ***Iran department of Energy Engineering Zarqa UniversityZarqa 13132Jordan department of Informatics University of OsloOslo 0316Norway department of Computer Science MalmöUniversityMalmö20506Sweden Shandong Provincial university Laboratory for Protected Horticulture Weifang University of Science and TechnologyWeifang 261100China department of electrical and Electronics Engineering NişantaşıUniversityIstanbul 34481742Türkiye

The network switches in the data plane of Software Defined Networking (SDN) are empowered by an elementary process, in which enormous number of packets which resemble big volumes of data are classified into specific flows by matching them against a set of dynamic rules. This basic process accelerates the processing of data, so that instead of processing singular packets repeatedly, corresponding actions are performed on corresponding flows of packets. In this paper, first, we address limitations on a typical packet classification algorithm like Tuple Space Search (TSS). Then, we present a set of different scenarios to parallelize it on different parallel processing platforms, including Graphics Processing Units (GPUs), clusters of Central Processing Units (CPUs), and hybrid clusters. Experimental results show that the hybrid cluster provides the best platform for parallelizing packet classification algorithms, which promises the average throughput rate of 4.2 Million packets per second (Mpps). That is, the hybrid cluster produced by the integration of Compute Unified Device Architecture (CUDA), Message Passing Interface (MPI), and OpenMP programming model could classify 0.24 million packets per second more than the GPU cluster scheme. Such a packet classifier satisfies the required processing speed in the programmable network systems that would be used to communicate big medical data.

关键词： OpenMP Compute Unified Device Architecture(CUDA) Message Passing Interface(MPI) packet classification medical data tuple space algorithm Graphics Processing Unit(GPU)cluster

Fire and Smoke Detection Using Wavelet Analysis and Disorder Characteristics

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Fire and Smoke Detection Using Wavelet Analysis and Disorder...

Stochastic framework for reliability enhancement using optimal feeder reconfiguration

2011 3rd International Conference on Computer Research and Development(ICCRD 2011)

作者： Ali Rafiee Reza Tavakoli Reza Dianat Sara Abbaspour Mehregan Jamshidi electrical department islamic azad university-kazeroun branch kazeroun Iran islamic azad university-bushehr branch bushehr Iran Persian Gulf university Bushehr Iran islamic azad university-kazeroun branch kazeroun Iran

The fire and smoke monitoring systems are useful in different industry such as military,social security and *** recent methods for fire and smoke detection are used only motion and color characteristics thus many wrong alarms are happening and this is decrease the performance of the *** research presents a new method for fire and smoke detection through image *** this algorithm all objects in an image is considered and then check them to figure out which objects are smoke and *** color,motion and disorder are useful characteristics in fire and smoke detection *** of fire will blur the whole or part of the *** by processing of the video frames,different objects will *** to evaluate the features of objects,the goal objects （fire and smoke） can be defined ***-dimensional wavelet analysis is used in the presented *** results of this research present the proposed features that can reduce the wrong alarms and increase the system performances.

关键词： Fire and smoke detection Wavelet analysis Disorder features Color and motion features

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Journal of Systems Engineering and Electronics 2014年第5期25卷 901-910页

作者： Abdollah Kavousi-Fard Taher Niknam Mohammad-Reza Akbari-Zadeh Bahram Dehghan Nourabad Mamasani branch Islamic Azad University Electronic and electrical department Shiraz University of Technology

Optimal distribution feeder reconfiguration （DFR） is a valuable and costless approach to increase the load balance, reduce the amount of power losses, and improve the voltage of the buses. In this way, this paper aims to investigate the optimal DFR strategy as a proper tool to improve the reliability of the radial distribution networks. The idea of failure rate reduction is employed to see the effect of feeder current reduction on the reliability of the system more accurately. The objects to be investigated are system average interruption frequency index （SAIFI）, system average interruption duration index （SAIDI）, average energy not supplied （AENS） and total active power losses. The problem is then formulated in a stochastic framework based on the point estimate method （PEM） to handle the uncertainty effects. The feasibility and satisfying performance of the proposed method is examined on a standard IEEE test system.

关键词： reliability enhancement uncertainty distribution systems optimal reconfiguration.

Impurity effects on electrical conductivity of doped bilayer graphene in the presence of a bias voltage

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Chinese Physics B 2016年第7期25卷 316-323页

作者： E Lotfi H Rezania B Arghavaninia M Yarmohammadi department of Physics Sanandaj Branch Islamic Azad University department of Physics Razi University department of Physics Kermanshah Branch Islamic Azad University Young researchers and Elite Club Kermanshah Branch Islamic Azad University

We address the electrical conductivity of bilayer graphene as a function of temperature, impurity concentration, and scattering strength in the presence of a finite bias voltage at finite doping, beginning with a description of the tight-binding model using the linear response theory and Green＇s function approach. Our results show a linear behavior at high doping for the case of high bias voltage. The effects of electron doping on the electrical conductivity have been studied via changing the electronic chemical potential. We also discuss and analyze how the bias voltage affects the temperature behavior of the electrical conductivity. Finally, we study the behavior of the electrical conductivity as a function of the impurity concentration and scattering strength for different bias voltages and chemical potentials respectively. The electrical conductivity is found to be monotonically decreasing with impurity scattering strength due to the increased scattering among electrons at higher impurity scattering strength.

关键词： bilayer graphene Green's function electrical conductivity

Multi-objective energy management of island microgrids with D-FACTS devices considering clean energy, storage systems and electric vehicles

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Clean Energy 2023年第5期7卷 1046-1057页

作者： Mahyar Moradi Mohamad Hoseini Abardeh Mojtaba Vahedi Nasrin Salehi Azita Azarfar department of electrical Engineering Shahrood BranchIslamic Azad UniversityShahroodIran department of Basic Sciences Shahrood BranchIslamic Azad UniversityShahroodIran

The development of microgrids is progressing due to intelligent load demands,clean energy,batteries and electric *** presence of such systems in microgrids causes power balance inconsistency,leading to increased power losses and deviation in *** this pa-per,a mixed-integer non-linear programming model is proposed for modelling island microgrid energy management considering smart loads,clean energy resources,electric vehicles and ***,a flexible distributed AC transmission system device is proposed to prevent voltage deviation and reduce power losses.A scenario-based multi-objective function has been proposed to decrease energy losses and voltage deviations and energy outages of clean energy resources,reduce emissions from fossil-fired distributed generation and finally decrease load outages to reduce the vulnerability of the islanded *** the proposed mixed-integer non-linear model and the high number of variables and constraints,a modified evolutionary algorithm based on particle swarm optimization has been proposed to solve the proposed model,which can be more efficient than other algorithms to achieve global optimal *** model presented is implemented on a 33-node island microgrid and the results illustrate that the proposed algorithm and model are effective in reducing energy losses and voltage deviation,as well as reducing the vulnerability of the *** simulation results demonstrate that the proposed approach can lead to significant improvements in the performance of the ***,the ap-proach can result in a 27%reduction in losses,a 6%reduction in pollution and a 31%improvement in ***,the approach allows maximum utilization of renewable energy sources,making it a promising solution for sustainable energy management.

关键词： microgrid D-FACTS clean energy battery electric vehicles evolutionary algorithm

Working Mechanism of a BC_3 Nanotube Carbon Monoxide Gas Sensor

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Communications in Theoretical Physics 2013年第7期60卷 113-118页

作者： Ali Ahmadi Peyghan Sirous Yourdkhani anMaziar Noei Chemistry department Central Tehran Branch Islamic Azad University Chemistry department Garmsar Branch Islamic Azad University department of Chemistry Mahshahr Branch Islamic Azad University

Carbon and BN nanotubes have previously demonstrated extreme sensitivity to several molecules, but they cannot be used to detect highly toxic molecules of CO. In this work, we examine the possibility of a BC3 nanotube (BC3NT) as a potential gas sensor for CO detection by using density functional theory calculations. It is found that CO molecule can be absorbed on B and C atoms of BC3 NT wall with adsorption energies in the range of 1.0 to 25.9 kcal/mol and it can donate finite charge to the tube. By comparing the HOMO/LUMO energy gaps of the bare and CO adsorbed nanotubes, we deduce that molecular CO can induce significant change in the electrical conductivity of the tube. The conductivity change can generate an electrical signal, which might be useful for CO detection.

关键词： sensor boron carbide nanotubes DFT carbon monoxide

Vehicle path tracking by integrated chassis control

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Journal of Central South university 2015年第4期22卷 1378-1388页

作者： Saman Salehpour Yaghoub Pourasad Seyyed Hadi Taheri department of Mechanical Engineering Tabriz Branch Islamic Azad University Faculty of electrical Engineering Urmia university of Technology Young Researchers and Elite Club Tabriz Branch Islamic Azad University

The control problem of trajectory based path following for passenger vehicles is studied. Comprehensive nonlinear vehicle model is utilized for simulation vehicle response during various maneuvers in MATLAB/Simulink. In order to follow desired path, a driver model is developed to enhance closed loop driver/vehicle model. Then, linear quadratic regulator(LQR) controller is developed which regulates direct yaw moment and corrective steering angle on wheels. Particle swam optimization(PSO) method is utilized to optimize the LQR controller for various dynamic conditions. Simulation results indicate that, over various maneuvers, side slip angle and lateral acceleration can be reduced by 10% and 15%, respectively, which sustain the vehicle stable. Also, anti-lock brake system is designed for longitudinal dynamics of vehicle to achieve desired slip during braking and accelerating. Proposed comprehensive controller demonstrates that vehicle steerability can increase by about 15% during severe braking by preventing wheel from locking and reducing stopping distance.

关键词： vehicle dynamics active control system optimal controller electronic stability program(ESP) particle swam optimization(PSO)

A new image watermarking framework based on levels-directions decomposition in contourlet representation

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Journal of Central South university 2017年第3期24卷 521-532页

作者： M.F.Kazemi M.A.Pourmina A.H.Mazinan department of electrical and Computer Engineering Science and Research BranchIslamic Azad University(IAU)TehranIran department of Control Engineering Faculty of Electrical EngineeringSouth Tehran BranchIslamic Azad University(IAU)TehranIran

With the development of digital information technologies,robust watermarking framework is taken into real consideration as a challenging issue in the area of image processing,due to the large applicabilities and its utilities in a number of academic and real *** are a wide range of solutions to provide image watermarking frameworks,while each one of them is attempted to address an efficient and applicable *** reality,the traditional techniques do not have sufficient merit to realize an accurate *** to the fact that the main idea behind the approach is organized based on contourlet representation,the only state-of-the-art materials that are investigated along with an integration of the aforementioned contourlet representation in line with watermarking framework are concentrated to be able to propose the novel and skilled *** a word,the main process of the proposed robust watermarking framework is organized to deal with both new embedding and de-embedding processes in the area of contourlet transform to generate watermarked image and the corresponding extracted logo image with high *** fact,the motivation of the approach is that the suggested complexity can be of novelty,which consists of the contourlet representation,the embedding and the corresponding de-embedding modules and the performance monitoring including an analysis of the watermarked image as well as the extracted logo *** is also a scrambling module that is working in association with levels-directions decomposition in contourlet embedding mechanism,while a decision maker system is designed to deal with the appropriate number of sub-bands to be embedded in the presence of a series of simulated *** required performance is tangibly considered through an integration of the peak signal-to-noise ratio and the structural similarity indices that are related to watermarked *** the bit error rate and the normal correlation are considered that are

关键词： contourlet based watermarking framework levels-directions decomposition embedding process de-embedding process peak signal-to-noise ratio structural similarity indices normal correlation bit error rate