检索结果-南通市图书馆

IEEE/CAA Journal of Automatica Sinica 2024年第11期11卷 2191-2203页

作者： mahdi taheri Khashayar Khorasani Nader Meskin the Department of Electrical and Computer Engineering Concordia University the Department of Electrical Engineering Qatar University

In this paper, we study stealthy cyber-attacks on actuators of cyber-physical systems(CPS), namely zero dynamics and controllable attacks. In particular, under certain assumptions, we investigate and propose conditions under which one can execute zero dynamics and controllable attacks in the CPS. The above conditions are derived based on the Markov parameters of the CPS and elements of the system observability matrix. Consequently, in addition to outlining the number of required actuators to be attacked, these conditions provide one with the minimum system knowledge needed to perform zero dynamics and controllable cyber-attacks. As a countermeasure against the above stealthy cyber-attacks, we develop a dynamic coding scheme that increases the minimum number of the CPS required actuators to carry out zero dynamics and controllable cyber-attacks to its maximum possible value. It is shown that if at least one secure input channel exists, the proposed dynamic coding scheme can prevent adversaries from executing the zero dynamics and controllable attacks even if they have complete knowledge of the coding system. Finally, two illustrative numerical case studies are provided to demonstrate the effectiveness and capabilities of our derived conditions and proposed methodologies.

关键词： Controllable attacks cyber-physical systems(CPS) dynamic coding zero dynamics attacks stealthy cyber-attacks

Modeling of the Shale Volume in the Hendijan Oil Field Using Seismic Attributes and Artificial Neural Networks

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2021年第4期95卷 1322-1331页

作者： mahdi taheri Ali Asghar CIABEGHODSI Ramin NIKROUZ Ali KADKHODAIE Seismology Geophysics Urmia UniversityUrmiaIran Department of Geology Faculty of SciencesUrmia UniversityUrmiaIran Earth Sciences Department Faculty of Natural SciencesTabriz UniversityTabrizIran

Petrophysical properties have played an important and definitive role in the study of oil and gas reservoirs,necessitating that diverse kinds of information are used to infer these *** this study,the seismic data related to the Hendijan oil field were utilised,along with the available logs of 7 wells of this field,in order to use the extracted relationships between seismic attributes and the values of the shale volume in the wells to estimate the shale volume in wells *** the overall survey of data,a seismic line was selected and seismic inversion methods(model-based,band limited and sparse spike inversion)were applied to *** all of these techniques,the model-based method presented the better *** using seismic attributes and artificial neural networks,the shale volume was then estimated using three types of neural networks,namely the probabilistic neural network(PNN),multi-layer feed-forward network(MLFN)and radial basic function network(RBFN).

关键词： seismic inversion seismic attributes artificial neural network and shale volume Hendijan oil field

Fuzzy Adjacency Matrix in Graphs

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

通讯和计算机（中英文版） 2012年第4期9卷 384-386页

作者： mahdi taheri Mehrana Niroumand Department of Mathematics Islamic Azad University Malayer branch Malayer Hamedan P. Box. 65718/117 Iran

Green synthesis of silver nanoneedles using shallot and apricot tree gum

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

Transactions of Nonferrous Metals Society of China 2015年第10期25卷 3286-3290页

作者： Mohammad mahdi taheri Mohammed Rafiq ABDUL KADIR Noor Kamila AHMAD SHAFIAI Tolou SHOKUHFAR Mahtab ASSADIAN Mostafa Rezazadeh SHIRDAR Materials Engineering Department Faculty of Mechanical EngineeringUniversiti Teknologi Malaysia Medical Devices & Technology Group Faculty of Bioscience and Medical EngineeringUniversiti Teknologi Malaysia Department of Mechanical Engineering-Engineering Mechanics Multiscale Technologies InstituteMichigan Technological University Department of Bioengineering University of Illinois at Chicago

A green synthesis method to produce silver nanoneedles was described using shallot and apricot tree gum（ATG）.A fast,simple,and low cost method was used to synthesize silver with nanoparticle and nanoneedle shape from the silver nitrate *** as a reducing agent and apricot tree gum（ATG） as a stabilizer and a capping agent were utilized to reduce and form silver ions into silver atoms with needle and particle ***,high crystalline structures of silver nanoparticles（AgNPs） with diameters of 8-20 nm and silver nanoneedles with average diameters of 50-60 nm and lengths of 5-10 μm were consequently synthesized by shallot and the mixture of shallot and ATG.A self-assembly mechanism was proposed to indicate the formation of needle-like structures of spherical Ag NPs via carbon chains of *** results indicate that the presence of ATG with shallot can transfer the reduced Ag NPs into the silver *** findings were characterized using X-ray diffraction（XRD）,ultra violet visible（UV-Vis） spectrometry,field emission scanning electron microscopy（FESEM）,and transmission electron microscopy（TEM） techniques.

关键词： green synthesis silver nanoneedle nanoparticle shallot apricot tree gum self-assembly

Germanium separation and purification by leaching and precipitation

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2016年第9期23卷 2214-2222页

作者： Saeid Bayat Sajjad Aghazadeh Mohammad Noaparast mahdi Gharabaghi Behrooz taheri School of Mining Engineering College of Engineering University of Tehran

In this research work, extraction and purification of germanium from zinc leach residues(ZLR) were investigated. The results of ICP, XRF, and atomic adsorption spectroscopy(AAS) tests show that contents of germanium, iron, lead, and zinc within the leaching residue were 105×10^(-6), 3.53%, 10.35%, and 8.8%, respectively. XRD results indicate that the main minerals were in different forms of sulfates(CaSO_4·2H_2O, PbSO_4 and ZnSO_4·6H__2O), silicate(SiO_2), and oxide(Fe_2O_3). Dissolution of leaching filter cake was carried out using 5 parameters and each in 4 levels(acid concentration, temperature, time, liquid-to-solid ratio, and stirring speed) by Taguchi method(L_(16)), and then optimization of the effective parameters by response surface method. Under optimum conditions, zinc and germanium dissolution efficiencies were 88.71% and 8%, respectively. Leaching tests with sulfuric acid(added di-ammonium oxalate monohydrate) and hydrochloric acid(HCl) on the residues obtained from previous-stage sulfuric acid dissolution, yielded germanium and iron recoveries of 83%, 88%, 40%, and 90%, respectively. Thus, leaching experiment with sulfuric acid(added di-ammonium oxalate monohydrate) was superior to that with hydrochloric acid due to high and low extraction amounts of germanium and iron, respectively. Precipitation experiments revealed that germanium purification with tannic acid presented a better result compared to sodium hydroxide and ammonia. Under optimum conditions, contents of germanium and iron in the solution after precipitation were 0.1505% and 14.7% with precipitation yields of 91% and 52%, respectively.

关键词： experimental design di-ammonium oxalate monohydrate germanium leaching, tannic acid