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Behavior modeling and verification of movement authority scenario of Chinese Train Control System using AADL

Science China(Information Sciences) 2015年第11期58卷 125-144页

作者： ahmad ehsan DONG YunWei LARSON Brian Lü JiDong TANG Tao ZHAN NaiJun School of Computer Science Northwestern Polytechnical University State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Computing and Information Systems Kansas State University State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University

Train control systems like most digital controllers are, by definition, hybrid systems as they interact with or try to control some aspects of the physical world. Detailed behavior modeling with constraints specification and formal verification, required for reliability prediction, is a great challenge for hybrid system *** control systems further intensify this challenge with extensive interaction between computing units and their physical environment and their mutual dependence on each other. In this paper, we investigate behavior modeling and formal verification of Chinese Train Control System Level 3(CTCS-3) using Architectural Analysis & Design Language(AADL) to cope with this challenge. AADL is an architecture description language for embedded systems and is based on model-based engineering paradigm. Along with structural modeling of embedded systems using the core language constructs, AADL also provides support for language extension through annex sublanguages. In system requirements specification document, the behavior of the CTCS-3 is specified as a set of basic operation scenarios that cooperate with each other to achieve safe and secure functionality of *** Authority(MA) scenario, explored in this paper, is considered as a basic and most crucial scenario to prevent trains from colliding with each other. The detailed discrete behavior of control system is modeled and verified using the Behavior Language for Embedded Systems with Software(BLESS) annex sublanguage of AADL, and the continuous behavior of train with the cyber–physical interaction(communication between train and control system) is modeled using the Hybrid annex sublanguage. The behavior of the MA scenario at system level is verified using the Hybrid Hoare Logic theorem prover. Behavior constraints are specified as assertions using first-order logic formulas augmented with a simple temporal operator.

关键词： AADL behavior modeling BLESS annex CTCS hybrid annex train control system

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Monte-Carlo-based simulation and investigation of 230 kV transmission lines outage due to lightning

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High Voltage 2020年第1期5卷 83-91页

作者： ehsan Karami ahmad Khalilinia Afshar Bali Kumars Rouzbehi Electrical Engineering Department Sharif University of TechnologyTehranIran West Regional Electric Company KermanshahIran Department of System Engineering and Automatic Control University of Seville41004 SevilleSpain

Here,using the probabilistic evaluation based on the Monte Carlo method,back-flashover rate and shielding failure flashover rate of 230 kV overhead transmission lines in the western regions of Iran are *** such an aim,first,the number of thunderstorm days per year is collected from the reported weather information in order to determine the ground flash ***,using MRU-200 equipment,the tower-footing resistance of several towers is ***®software is used in order to produce lightning surges considering its probabilistic nature and randomly distribution on the ground to evaluate striking distance based on the geometric ***,calculated parameters are transferred to EMTP-RV software by establishing a link to perform the transient simulation and report the results for modelled 230 kV transmission ***,considering IEEE-1243 standard,it is shown that due to high ground flash density,using 230 kV tower with one shield wire is not sufficient to protect the line against lightning phenomena.

关键词： flash lightning probabilistic

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Tribological behavior of ZK60Gd alloy reinforced by SiC particles after precipitation hardening

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Journal of Magnesium and Alloys 2023年第9期11卷 3362-3381页

作者： ehsan Momeni Hassan Sharifi Morteza Tayebi ahmad Keyvani Ermia Aghaie Yashar Behnamian Department of Materials Science and Engineering University of ShahrekordIran Young Researchers and Elites Club Science and Research BranchIslamic Azad UniversityTehranIran Department of Chemical and Materials Engineering University of AlbertaEdmontonAlberta T6G 1H9Canada

In this research, the effect of precipitation hardening on the tribological behavior of the ZK60Gd/SiC composite was studied. For this purpose, ZK60Gd alloy containing with 5 and 10 wt% SiC were produced with stir casting method. The microstructure characterization of the samples showed the wide distributions of Mg_(7)Zn_(3) and Gd(Mg_(0.5)Zn_(0.5)) precipitates were formed during casting. The results of hardness measurement after precipitation hardening at different temperatures showed that the hardness peck was obtained at 175 ℃. The wear tests with different loads(10, 40, 60, 90, and 120 N) and velocities(0.1, 0.3, 0.6, and 0.9 m/s) were performed on the as-cast and heat treated sample at 125, 175, and 225 for 12 h. Between the different precipitation hardening conditions, the precipitation hardened samples at 175 ℃ had the highest hardness values and least wear rate. The sample containing 10% reinforcement had the least wear rate between the unreinforced alloy and the composites. The results showed that abrasive, adhesive, delamination, MML, and fatigue wear mechanisms were the dominant wear mechanisms for the composite samples. In contrast, the dominant wear mechanism for the unreinforced samples was abrasive, adhesive,delamination, MML, and plastic deformation.

关键词： Precipitation hardening Composite Gadolinium Mg-Zn-Zr-Gd Wear map

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SIMULATION OF VISCOELASTIC FLUID FLOWS IN EXPANSION GEOMETRY USING FINITE VOLUME APPROACH

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Chinese Journal of Polymer Science 2013年第12期31卷 1599-1612页

作者： Morteza Azizi ahmad Ramazani S.A Habib Etemadi M ehsan Shirzaei S Department of Chemical and Petroleum Engineering Sharif University of Technology

The simulation results on viscoelastic fluid flows in sudden expansion geometry with different expansion ratios are presented. Oldroyd-B, linear Phan-Thien-Tanner （L-PTT） and Finitely Extensible Nonlinear Elastic （FENE-P） based constitutive equations were applied in two-dimensional Cartesian coordinates. The governing equations in transient and fully developed regions were solved using open source software called OpenFOAM. The flow patterns, including velocity profiles, shear stresses and first normal stress differences in some horizontal and vertical sections are illustrated. In addition, effects of the fluid type, flow dynamics and expansion ratio on the flow and vortex patterns in transient and fully developed regions are presented and discussed. The presented results show that existences of vortices cause the inverse velocity and negative stresses in expansion regions of the channel which increase with increment of expansion ratio and Weissenberg number （We）. Furthermore, some dead spaces can be observed at channel expansion regions close to the wall which are also increased. The results also show that at low We numbers all fluids show close behavior while at high We numbers the FENE-P fluid behavior shows high divergence from that of the two other fluids.

关键词： Expansion flow Simulation Finite Volume OpenFOAM Viscoelastic Fluids.

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Tissue tropism and parasite burden of Toxoplasma gondii RH strain in experimentally infected mice

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Asian Pacific Journal of Tropical Medicine 2014年第7期7卷 521-524页

作者： Yousef Dadimoghaddam ahmad Daryani Mehdi Sharif ehsan ahmadpour Zahra Hossienikhah Toxoplasmosis Research Center Mazandaran University of Medical Sciences Parasitology and Mycology Department.Sari Medical School Mazandaran University of Medical Sciences Molecular and Cell Biology Research Center Mazandaran University of Medical Sciences

Objective:To evaluate parasite distribution and tissue tropism of Toxoplasma gondii tachyzoites in experimentally infected mice using real time ***:In this survey 16 Balb/c mice were inoculated with 1×10~4 alive tachyzoites of Toxoplasma gondii RH *** 1,2,3 days post infection and the last day(before death),different tissues of mice including blood,brain,eye,liver,spleen,kidney,heart and muscle were *** tissues DNA extraction,the parasite burden was quantified using real time QPCR targeting the B1 gene(451 bp).Results:It showed that Toxoplasma after intraperitoneal injection was able to movement to various tissues in24 *** burden was high in all tissues but the most number of parasites were observed in kidney,heart and liver,***:These data provide significant baseline information about Toxoplasma pathogenesis,vaccine monitoring and drug efficiency.

关键词： Parasite burden Toxoplasma gondii Tissue tropism Quantitative PCR Murine model

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Application of diffusive transport model for better insight into retardation mechanisms involved in ion-imprinted membrane transport

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Chinese Journal of Chemical Engineering 2016年第9期24卷 1161-1165页

作者： ehsan Salehi Department of Chemical Engineering Faculty of Engineering Arak University

Heavy metal removal from water is a great concern for environmentalists and engineers. Ion-imprinted membranes are among the state of the art technologies for selective adsorption of heavy metals from aqueous environment. Dialysis permeation of nickel ions through Ni(II)-imprinted membranes has been thermodynamically studied in our prior work. In current study, the diffusive transport model was developed and then applied for better insight into the retardation mechanisms involved in the ion-imprinted membrane transport. The Sips isotherm model was coupled with the transport model to obtain the governing equation. Chemisorption and physical interactions(bulk diffusion and pore-clogging) were the most probable retardation mechanisms according to the modeling results. Relative retardation factor(η) was also defined as; transport-rate controlled by chemical adsorption to that controlled by physical interactions. With the help of the retardation factor, it was understood that the membrane behavior gradually changes from chemisorption to facilitated transport during permeation time. Effect of important operating parameters such as time, temperature and concentration on transport behavior was also investigated. Results indicated that chemisorption rate is rather higher at lower concentrations, early permeation times and reduced temperatures. In addition, η tabulated greater values for Ni(II) compared to Co(II) due to the imprinting effect.

关键词： Ion-imprinted membrane Mathematical modeling Chemisorption Retardation mechanism

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Effects of modified graphene oxide(GO) nanofluid on wettability and IFT changes: Experimental study for EOR applications

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Petroleum Science 2022年第4期19卷 1779-1792页

作者： ehsan Jafarbeigi Farhad Salimi ehsan Kamari Mohsen Mansouri Department of Chemical Engineering Kermanshah BranchIslamic Azad UniversityKermanshahIran Department of Petroleum Engineering Research Institute of Petroleum IndustryTehranIran Department of Chemical Engineering llam UniversityllamIran

The application of nanoparticles(NPs) in enhanced oil recovery(EOR) offers a practical approach to resolving some surface-related problems encountered in contemporary technological processes. In this study, graphene oxide nanosheets(GONs) were synthesized by Hummer's method and, then, were subjected to surface modification by hexamethyldisilazane(HMDS) and diazonium sulfonic(DS) compounds. The new combination was known as GO-Su-HMDS. The potential stability of GO-Su-HMDS nanofluids(NFs) was investigated using the zeta(ζ) potential test. A comparative study of the effect of the synthesized NFs on wettability alteration of the reservoir rock was performed using interfacial tension(IFT) and contact angle experiments. According to the results of this study, the contact angle decreased from the initial value of 161.(oil wet) to 35.(water wet). In addition, IFT decreased from18.45 mN/m for deionized(DI) water to 8.8 mN/m for 500 ppm GO-Su-HMDS NF. Moreover, the results of flooding experiments showed that the NPs of a GO-Su-HMDS concentration of 400 and 500 ppm could increase the oil recovery by 20% and 19%, respectively. The experimental results showed that GO-SuHMDS NFs with a concentration of 500 ppm have the best efficiency in terms of altering the wettability of the rock from oil wet to water wet. Thus, it can be said that this nanofluid can reduce the contact angle and IFT and also increase the sweeping efficiency of oil.

关键词： Wettability alteration Graphene oxide Contact angle Interfacial tension Zeta potential

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Discrete element modeling of inherently anisotropic granular assemblies with polygonal particles

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Particuology 2012年第5期10卷 542-552页

作者： ehsan Seyedi Hosseininia Civil Engineering Department Faculty of Engineering Ferdowsi University of MashhadMashhad Iran

In the present article, we study the effect of inherent anisotropy, i.e., initial bedding angle of particles and associated voids on macroscopic mechanical behavior of granular materials, by numerical simulation of several biaxial compression tests using the discrete element method （DEM）. Particle shape is considered to be irregular convex-polygonal. The effect of inherent anisotropy is investigated by following the evolution of mobilized shear strength and volume change during loading. As experimental tests have already shown, numerical simulations also indicate that initial anisotropic condition has a great influence on the strength and deformational behavior of granular assemblies. Comparison of simulations with tests using oval particles, shows that angularity influences both the mobilized shear strength and the volume change regime, which originates from the interlocking resistance between particles.

关键词： Inherent anisotropyGranular materialDiscrete element methodPolygonal particles

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Quantization and Event-Triggered Policy Design for Encrypted Networked Control

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 946-955页

作者： Yongxia Shi ehsan Nekouei the Department of Electrical Engineering City University of Hong KongHong KongChina

This paper proposes a novel event-driven encrypted control framework for linear networked control systems(NCSs),which relies on two modified uniform quantization policies,the Paillier cryptosystem,and an event-triggered *** to the fact that only integers can work in the Pailler cryptosystem,both the real-valued control gain and system state need to be first quantized before *** is dramatically different from the existing quantized control methods,where only the quantization of a single value,e.g.,the control input or the system state,is *** handle this issue,static and dynamic quantization policies are presented,which achieve the desired integer conversions and guarantee asymptotic convergence of the quantized system state to the ***,the quantized system state is encrypted and sent to the controller when the triggering condition,specified by a state-based event-triggered strategy,is *** doing so,not only the security and confidentiality of data transmitted over the communication network are protected,but also the ciphertext expansion phenomenon can be ***,by tactfully designing the quantization sensitivities and triggering error,the proposed event-driven encrypted control framework ensures the asymptotic stability of the overall closedloop ***,a simulation example of the secure motion control for an inverted pendulum cart system is presented to evaluate the effectiveness of the theoretical results.

关键词： Cyber-security encrypted control event-triggered control(ETC) networked control systems(NCSs) semi-homomorphic encryption

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Plant-pollinator metanetworks in fragmented landscapes:a simulation study

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Ecological Processes 2023年第1期12卷 415-424页

作者： ehsan Rahimi Chuleui Jung Agricultural Science and Technology Institute Andong National UniversityAndong City 36729Republic of Korea Department of Plant Medicals Andong National UniversityAndong CityRepublic of Korea

Background The topology of the plant-pollinator network can be explained by the species’abundance and their random ***-pollinator networks can be studied in the context of a landscape,because each patch can accommodate a certain local *** populations of pollinators in the landscape can be connected through migration and then constitute a metanetwork that is known as a combination of spatial and ecological *** this regard,habitat fragmentation can affect the topology of plant-pollinator metanetworks through changes in the species abundance and limiting their ***,it is not clear what pattern(fragmented or aggregated)of the landscape structure can accommodate networks with a higher degree of *** we created simulated landscapes with different forest proportions scenarios(from 5%to 50%of the total landscape)and degrees of ***,for each landscape,we limited the proportion of pollinators to the forest *** assumed that plants and pollinators are randomly distributed around the landscape and interact *** used landscape metrics to measure different aspects of landscape structure and bipartite metrics for calculating the degree of specialization in plant-pollinator *** The statistical relationship between bipartite and landscape metrics showed that the relationship between the topology of plant-pollinator networks and the landscape structure is affected by the forest amount in the landscape and the degree of forest *** also found that according to the nestedness and H2(a measure of specialization)metrics,fragmented landscapes contain more general plant-pollinator *** Our findings suggest that fragmented landscapes,characterized by scattered forest patches,can promote higher levels of interaction between limited pollinators and diverse flowers,leading to more general plant-pollinator networks.

关键词： Plant–pollinator metanetwork Habitat fragmentation Simulated landscape Landscape metrics Bipartite metrics

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