检索结果-南通市图书馆

Enhanced two-loop model predictive control design for linear uncertain systems

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2021年第1期32卷 220-227页

作者： Mohammad-Ghassem FARAJZADEH-DEVIN seyed Kamal hosseini SANI Department of Electrical Engineering Ferdowsi University of MashhadMashhad 1696700Iran

Model predictive controllers(MPC)with the two-loop scheme are successful approaches practically and can be classified into two main categories,tube-based MPC and MPCbased reference governors(RG).In this paper,an enhanced twoloop MPC design is proposed for a pre-stabilized system with the bounded uncertainty subject to the input and state *** proposed method offers less conservatism than the tube-based MPC methods by enlarging the restricted input *** to the MPC-based RGs,the investigated method improves tracking performance of the pre-stabilized system while satisfying the ***,the robust global asymptotic stability of the closed-loop system is guaranteed in a novel procedure with terminal constraint *** of the proposed method on a servo system shows its effectiveness in comparison to the others.

关键词： model predictive control(MPC) robust control cascade control constraint satisfaction

Automatic recognition of sonar targets using feature selection in micro-Doppler signature

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2023年第2期20卷 58-71页

作者： abbas Saffari seyed-Hamid Zahiri Mohammad Khishe Department of Electrical Engineering University of BirjandBirjandIran Department of Electrical Engineering Imam Khomeini Marine Science UniversityNowshahrIran

Currently,the use of intelligent systems for the automatic recognition of targets in the fields of defence and military has increased *** primary advantage of these systems is that they do not need human participation in target recognition *** paper uses the particle swarm optimization(PSO)algorithm to select the optimal features in the micro-Doppler signature of sonar *** microDoppler effect is referred to amplitude/phase modulation on the received signal by rotating parts of a target such as *** different targets'geometric and physical properties are not the same,their micro-Doppler signature is *** Inconsistency can be considered a practical issue(especially in the frequency domain)for sonar target *** using 128-point fast Fourier transform(FFT)for the feature extraction step,not all extracted features contain helpful *** a result,PSO selects the most optimum and valuable *** evaluate the micro-Doppler signature of sonar targets and the effect of feature selection on sonar target recognition,the simplest and most popular machine learning algorithm,k-nearest neighbor(k-NN),is used,which is called k-PSO in this paper because of the use of PSO for feature *** parameters measured are the correct recognition rate,reliability rate,and processing *** simulation results show that k-PSO achieved a 100%correct recognition rate and reliability rate at 19.35 s when using simulated data at a 15 dB signal-tonoise ratio(SNR)angle of 40°.Also,for the experimental dataset obtained from the cavitation tunnel,the correct recognition rate is 98.26%,and the reliability rate is 99.69%at ***,the k-PSO has an encouraging performance in automatically recognizing sonar targets when using experimental datasets and for real-world use.

关键词： Micro-Doppler signature Automatic recognition Feature selection k-NN PSO

Assessment of seismic amplification factor of excavation with support system

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2019年第3期18卷 555-566页

作者： Hamidreza Tavakoli Saman Soleimani Kutanaei seyed Hossein hosseini Department of Civil Engineering Babol University of Technology P.O. Box 484 Babol Iran Department of Civil Engineering Rouzbahan Institute of Higher Education Sari Iran Department of Civil Engineering Hamedan Branch Islamic Azad University P.O. Box 65181-15743 Hamedan Iran

Retaining walls have been used in many construction projects such as for road and inclined surfaces protection. The damage caused by an earthquake depends on the fundamental frequency, amplitude and the duration of the seismic motion. These parameters strongly depend on the seismic properties of the layers that are near the surface. In the study of retaining walls, in addition to the infl uence of soil, the infl uence of topography is also important. In the present study, site response analysis is performed by using fi nite element software PLAXIS to obtain the eff ect of various factors such as embedded length of the sheet pile, underground water table, length and angle of the nail, shear wave velocity of soil on site eff ect and dynamic response. Moreover, for better understanding of the eff ect of the above parameters, the stability analysis was performed by using shear reduction method. The results show that an increase in the embedded length of the sheet pile and the length of nailing causes an increase in the amplifi cation factor. Moreover, for shear-wave velocity in the range of 200- 600 m/s, the amplifi cation factor increases with increase of the shear-wave velocity due to the decrease of nonlinear behavior.

关键词： amplifi cation factor safety factor shear wave velocity nailing sheet pile

A generalized set of correlations for plus fraction characterization

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2012年第3期9卷 370-378页

作者： JAMIALAHMADI Mohamad ZANGENEH Hossein hosseini seyed Sajad Petroleum Engineering Department Petroleum University of Technology Chemical & Petroleum Engineering Department Sharif University of Technology

The importance of accurate determination of the critical properties of plus fractions in prediction of phase behaviour of hydrocarbon mixtures by equations of state is well known in the petroleum industry. It has been stated in various papers （Elsharkawy, 2001） that using the plus fraction as a single group in equation of state calculations reduces the accuracy of the results. However in this work it has been shown that using the proper values of critical temperature and pressure for the plus fraction group can estimate the properties of hydrocarbon mixtures, and they are accurate enough to be used in reservoir engineering and enhanced oil recovery calculations. In this paper, a new method is proposed for calculating the critical properties of plus fractions of petroleum fluids. One can use this method either in predicting critical pressure and temperature of single carbon numbers （SCNs） after the splitting process or in predicting critical pressure and temperature of the plus fraction as a single group. A comparison study is performed against Riazi-Daubert correlation （Riazi and Daubert, 1987） and Sancet correlations （Sancet, 2007） for 25 oil samples taken from 14 fields from southwest Iran. The results indicate the superiority of the proposed method to the Riazi-Daubert and Sancet correlations.

关键词： Plus fraction critical properties correlation single carbon number bubble point calculations

Numerical Simulation of the Mechanical Properties of Sintered and Bonded Perforated Hollow Sphere Structures (PHSS)

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2010年第8期26卷 730-736页

作者： Andreas chsner seyed Mohammad Hossein hosseini Markus Merkel Department of Applied Mechanics Technical University of Malaysia Centre for Mass and Mechanical Transport in Engineering Materials The University of Newcastle CallaghanNewSouth Wales 2308Australia Department of Mechanical Engineering University of Applied Sciences Aalen

This paper investigated the uniaxial mechanical properties of a new type of hollow sphere structures. For this new type, the sphere shell was perforated by several holes in order to open the inner sphere volume and surface. The mechanical properties, i.e. elastic properties and initial yield stress of perforated hollow sphere structures （PHSS） in a primitive cubic arrangement were numerically evaluated for different hole diameters and different joining techniques of the hollow spheres. The results are compared to classical configurations without perforation.

关键词： Mechanical properties Cellular material Porous structure Finite element method

Experimental Investigation and Semi-Active Control Design of A Magnetorheological Engine Mount

在线全文

学校读者我要写书评

暂无评论

Sound & Vibration 2019年第6期53卷 297-308页

作者： seyed Salman hosseini Javad Marzbanrad School of Automotive Engineering Iran University of Science and TechnologyTehranIran Faculty at School of Automotive Engineering Iran University of Science and TechnologyTehranIran

In this paper;the dynamic characteristics of a semi-active magnetorheological fluid(MRF)engine mount are *** do so,the performance of the MRF engine mount is experimentally examined in higher frequencies(50~170 Hz)and the various amplitudes(0.01~0.2 mm).In such an examination,an MRF engine mount along with its magnetically biased is fabricated and successfully *** addition,the natural frequencies of the system are obtained by standard hammer modal *** modelling the behavior of the system,a mass-spring-damper model with tuned PID coefficients based on Pessen integral of absolute error method is *** parameters of such a model including mass,damping ratio,and stiffness are identified with the help of experimental modal tests and the recursive least square method(RLS).It is shown that using PID controller leads to reducing the vibration transmissibility in the resonance frequency(=93.45 Hz)with respect to the typical passive engine mount by a factor of 58%.The average of the vibration transmissibility decreasing is also 43%within frequency bandwidth(50~170 Hz).

关键词： Semi-active engine mount PID controller experimental data least square method magnetorheological fluid

A complex solution on the dynamic response of sandwich graphene-reinforced aluminum-based composite beams with copper face sheets under two moving constant loads on an elastic foundation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Mechanical System Dynamics 2023年第3期3卷 251-264页

作者： Mohammadreza Eghbali seyed Amirhosein hosseini Department of Mechanical Engineering University of ZanjanZanjanIran Department of Industrial Mechanical and Aerospace EngineeringBuein Zahra Technical UniversityQazvinIran

An analytical solution was used to investigate the elastic response of a sandwich beam with a graphene-reinforced aluminum-based composite(GRAC)on an elastic foundation using copper as the face layer of the functionally graded composite beam and a simply supported boundary ***'s higher-order shear deformation theory was utilized to derive the equations,which were solved in Laplace space and then converted into space–time using Laplace *** exact response of the GRAC sandwich beam was obtained by considering the displacement at the mid-span of the sandwich *** moving loads with different speed ratios were applied at a single point,and the effect of various parameters,including the spring constant,the speed ratio,the percentage of graphene,the moving load speed,and the distribution pattern,was *** study aimed to eliminate any overlap and improve the accuracy of the *** exact solving method presented has not been reported in other articles so ***,due to the difficulty of solving mathematical equations,this method is only applicable to simple boundary conditions.

关键词： GRAC beams moving load Laplace transform elastic foundation analytical solution aluminum-based

Land-use change and carbon stocks: A case study, Noor County, Iran

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Forestry Research 2013年第3期24卷 461-469页

作者： Niloufar Haghdoost Moslem Akbarinia seyed Mohsen hosseini Department of Forestry Faculty of Natural Resources Tarbiat Modares UniversityNoor Mazandaran Iran. Postal code: 46417-76489 Department of Forestry Faculty of Natural Resources Tarbiat Modares UniversityNoor Mazandaran Iran

Land-use changes and land cover strongly influence carbon stock and distribution within ecosystems. Changing the land-use from natural forest to other land-uses has been more rapid in the past few decades than at any time in Iran＇s history. In this study, we investigated the effects of changing the land-use from natural forest to other land-uses on carbon stocks in northern Iran. We selected five sites for this study：（I） a natural forest, （II） an agricultural field and （III） plantations of three different species （Alnus subcordata .L, Acer velutinum .Boiss and Cu- pressus sempervirens）. We examined the effects of land-use changes on：（I） soil carbon stock （0-50 cm depth）, （II） biomass and carbon content of grassy vegetation and litter and （III） above- and below-ground biomass C in trees. Soil C stock was higher under A. velutinum and C. sempervirens whereas it was lower under A. subcordata and agricultural sites. Biomass and C content of grassy vegetation were significantly higher at A. veluti- num and C. sempervirens plantations. However, litter biomass and C content were significantly higher at the natural forest site. Natural forest had the highest amount of C content in above- and below-ground bio- mass. Total ecosystem C stocks declined following land-use changes.

关键词： biomass climate change mitigation Hyrcanian forests plan-tation soil organic carbon

Prediction of the Behavior of a Power System Using Root Cause Failure Analysis

在线全文

学校读者我要写书评

暂无评论

Fluid Dynamics & Materials Processing 2022年第3期18卷 815-833页

作者： seyed Mohammad seyed hosseini Kamran Shahanaghi Safar Shasfand Iran University of Science and Technology Tehran***Iran

The thermo-economic performance of a gas turbine is simulated using a fish bone technique to characterize the major equipment failure *** a fault tree analysis and a Pareto technique are implemented to identify the related failure modes,and the percentage and frequency of failures,respectively.A pump 101 and drier 301 belonging to the Tabriz Petrochemical Company are considered for such analysis,which is complemented with a regression method to determine a behavioral model of this equipment over a twenty-year *** findings indicate that 81%of major failure factors in production equipment are related to the executive procedures(24%),human error(22%),poor quality of materials and parts(20%),and lack of personnel training(15%).

关键词： Combined heat and power root analysis thermoeconomic performance fault tree Pareto behavioral model