Physical Sciences and Mathematics Commons^™

Multi-Objective Optimization Of The Main Circuit And Control Parameters Of The Buck-Boost Matrix Converter, Xiaoping Zhang, Wenhao Song, Hongping Zhu

Journal of System Simulation

Abstract: The optimization of main circuit parameters and control parameters of the Buck-Boost matrix converter has been investigated. The study takes the main circuit parameters and control parameters as optimization object and takes the harmonic distortion of output voltage, capacitance voltage deviation and inductance current deviation of the converter as optimization target. Firstly, multi-objective optimization satisfaction function is established correspondingly. Meanwhile, the fitness function is built and solved to achieve a set of optimizing parameters based on the fruit fly algorithm, which makes each optimizing target achieve synergistic optimal. Finally, the optimization effect is verified by simulation. The results show …

Simulation And Analysis Of Atmospheric Effects On Height Deriving From Insar, Xintian Wang, Guowang Jin, Xiong Xin, Hongmin Zhang, Xu Qing

Journal of System Simulation

Abstract: The atmospheric phase delay caused by tropospheric water vapor (WV) is an important factor to the precision of repeat-pass mode interferometry synthetic aperture radar (InSAR). To study the WV effect quantitatively, the regulation of WV effect in repeat-pass InSAR is analyzed and the simulation scheme is designed in which the DEM and WV model is used to simulate InSAR interferogram and WV delay phase, and the derived height is analyzed. The experiment is performed by using systems and baseline parameters of SAR images of Henan;WV effected interferogram is simulated using DEM and vertical layered WV model; and the derived …

Heat Transfer Simulation Of Vehicle Heat Exchanger In Plateau Environment, Xu Xiang, Wenchao Suo, Dingfu Yang, Surong Dong

Journal of System Simulation

Abstract: The effect of heat transfer caused by plateau environment in vehicle heat exchanger was investigated. The heat transfer equation for heat exchanger was modified by introducing air parameters at different altitudes. A heat transfer modeling approach for vehicle heat exchanger was proposed by using the thermal network method. The heat transfer effect of the plateau and the flow state of fluid medium were analyzed in the vehicle heat exchanger by using the simulation software FlowMaster. Simulation results show that the decrease of pressure and density of air in altitude was the primary cause to heat transfer ability. …

Simulation Assessment Of Degradation System Reliability Under Imperfect Maintenance, Haidong Du, Junhai Cao, Shen Ying, Shangru Teng

Journal of System Simulation

Abstract: For the state change characteristic of degradation system under imperfect maintenance, the common analysis method becomes useless. A simulation method for repairable system is presented. A change rule of system reliability was analyzed and a reliability assessment model was built on the foundation of components degradation process. A simulation tactics based on variable structure modeling was given which is realized through Agent technique. A maintenance optimization example was given for the determination of maintenance opportunity which is used to support the formulation and improvement of maintenance support program for repairable system.

Simulation Evaluation Method Of Mission Sustainability For Operational Unit, Yan Xu, Junhai Cao, Tailiang Song, Gao Long, Zhang Qiang

Journal of System Simulation

Abstract: To analyze and evaluate support capabilities of operational units and scientifically describe the operational mission sustainability of weapon systems, the typical mission models for individual operational unit and operational units were established according to system engineering ideology. The mission status of operational units was defined, and the parameters including mission sustainability and equipment availability of operational units were proposed. An operational unit mission process simulation model was established with the agent-based method, which provides a simulation method for operational unit mission sustainability evaluation and technical means for the operational unit support capability assessment problem. A case study of …

Modeling And Analysis For Underwater High-Speed Supercavitaing Torpedo, He Zhen, Aiping Pang, Jinghua Wang, Fanwei Meng, Guangxiong Wang

Journal of System Simulation

Abstract: Supercavitation technology can significantly reduce skin-friction drag of underwater torpedo, and therefore dramatically increase the velocity and attack power of underwater weapons. Because the torpedo is almost entirely enveloped by a supercavity, the hydrodynamic problems of the high-speed supercavitating torpedo (HSST) are complex. The hydrodynamic forces acting on cavitator, fin, and the planing force along the longitude plane of the underwater HSST are analyzed. A benchmark nonlinear dynamics model of supercavitating torpedo is established based on the basic dynamic equations of the longitude plane, and the specific parameters of HSST are calculated. In the longitude plane the motion equation …

A Horizon Detection Method Based On Deep Learning And Random Forest, Jihua Ye, Shuxia Shi, Hanxi Li, Jiali Zuo, Shimin Wang

Journal of System Simulation

Abstract: The detection effect of existing horizon line detection methods is greatly affected by the environment, and the computational complexity is high. Aiming at the problem of horizon line detection in complex road scene in real-life, a horizon line detection method based on deep learning and random forest is proposed. The deep learning model is used to extract the depth features, then the obtained depth features are used for random forest training. The results of horizon line detection are obtained by random forest regression-voting. The simulation results show that this method has good detection effect. The detection results are not …

Simulation And Experimental Verification Of Grinding Force Based On Different Directions Of Ultrasonic Vibration, Wang Yan, Qin Chen, Jianguo Liu, Shuiping Peng, Delin Li

Journal of System Simulation

Abstract: The method based on variable angle of ultrasonic vibration assisted grinding was put forward to identify the relationship between direction of ultrasonic vibration and grinding force. The trajectory of grit in contact zone was analyzed. The stress field of contact zone and the grinding force, which were based on the different directions of ultrasonic vibration, were simulated and analyzed by Deform-3D. A series of grinding experiments of GCr15 were conducted. It demonstrates that with the angle α increasing, the grinding force firstly decreased and then increased. The experiment results showed that the error of normal force is 5.23% and …

Method And Simulation Of Gradual Rough Milling Based On Surface Deformation, Xiulin Sui, Xiaoqi Chen, Jianghua Ge

Journal of System Simulation

Abstract: In view of uneven allowance and rough surface of traditional equal height stratification for rough milling, a gradual hierarchy process method was proposed. As the model established by T-spline surface has unified parameter domain, an improved variable distance offset method was used to define the rules of surface deformation, and a series of deformation surface sequences were obtained. The cutting depth, tool radius and other machining parameters were used as constraint conditions so as to get the sequence of processing layers. By planning the tool path of each layer, the whole tool path of gradual hierarchy process which was …

High Performance Fault-Tolerant Scheduling Method And Simulation For Heterogeneous Multicore, Shigan Yu, Zhimin Tang, Xiaochun Ye, Zhimin Zhang

Journal of System Simulation

Abstract: To deal with the problem of low performance and high power consumption when solving the transient fault of the processor with three mode redundancy (TMR), a task execution algorithm for heterogeneous multicore considering fault tolerant (TEAHFT) is proposed. The tasks to be executed are divided into sensitive tasks and fault-tolerant tasks. The sensitive tasks are executed in a TMR mode, and the fault-tolerant tasks are executed in a competitive scheduling mode. The task will be rerun in TMR method if the results of the fault-tolerant tasks do not meet the reliability threshold. The simulation experimental results show that TEAHFT …

Numerical Simulation And Experimental Study On The Rolling Process Of Polar Particles, Yanjun Xiao, Kong Xuan, Wang Zhao, Zonghua Zhang, Yanchun Xiao

Journal of System Simulation

Abstract: The densification process of electrical paste particles during the process of battery pole piece rolling is studied. The mechanism of the pole rolling is analyzed theoretical;the basic parameters of the electric slurry particles in the movement are described; the force equation is established; and the basic conditions for the stable rolling are analyzed. The dynamic simulation is carried out by using relevant parameters, and the results are verified by theoretical analysis, numerical simulation and experimental verification. The results show that there is a certain relationship between the relative density of the electrode paste and the thickness of the …

Simulation And Analysis Of Forced Caving Blasting Scheme For Overburden Steep Inclined Strata In Coal Mining, Tiejun Cui, Yundong Ma, Laigui Wang

Journal of System Simulation

Abstract: According to the actual situation of overburden steep inclined strata with horizontal fracture, the reasonable goaf forced caving blasting schemes are studied. Considering overburden characteristic and representative, two schemes are put forward with the attachment perpendicular to their break point locations. By setting different places of blasting points, the different directions of blasting and blasting area are determined, and the overlying strata movement and development characteristics of blasting fracture are analyzed. The overlying strata movement range is larger and can develop to the surface after blasting; The conclusion is that the influence range of the fracture is wide in …

Simulation Of Influence Of Coal-Based Industry On Water Resources Bearing System, Yalin Chen, Wangsheng Gui, Qianjin Dong, Ye Chun, Haotian Wu

Journal of System Simulation

Abstract: The contradictory spatial distribution between China's coal resources and water resources has become the stress to sustainable development of regional ecological environment and social economy. The paper presents interactive simulation model of regional water resources bearing system based on System Dynamics; and then Ningxia Hui Autonomous Region is used as an example, the dynamic process of local water bearing system was simulated under different scenarios of planning. The simulation results show that regional sustainable development of water resources would be achieved if the resources are allocated based on the market, while the gap between supply and demand of regional …

Simulation Research Of General Cargo Terminal Operation Based On Plant Simulation, Zhixiong Liu, Xiong Yang, Xingxu Deng, Yuting Chen

Journal of System Simulation

Abstract: Combined with the key link of the general cargo loading and unloading operations, the system simulation method is employed to analyze the production efficiency for the general cargo handling operation. The Plant Simulation software is used to design the main modules of the production process such as collection operation, vessel arrival, yard operation, horizontal transportation, ship-loading operation. The simulation model of general cargo handling operation is established based on the whole operation process. The simulation model is running based on the practical production data, and the efficiency of the crane, transitions time and the average storage period are analyzed. …

Mining And Validation Of Attacking Behavior In The Robocup 2d Simulation, Chen Bing, Zhang Heng, Zekai Cheng, Dong Peng, Lin Chao

Journal of System Simulation

Abstract: Robocup is an international academic competition which focuses on artificial intelligence and robotics. The 2D simulation is one of the earliest and most influential projects in Robocup. Attacking is the core behaviour of the simulated football game, as well as the attack recognition is considered as an important part in team-confrontations. This paper selects some active and contribution index of attacking, extracts lots of attacking behaviour data of the key agents, proposes two kinds of attacking patterns of 2D simulation, as ‘separate attack’ and ‘cooperative attack’, according to the human-player actions. The following simulation tests give the accuracy of …

Modeling And Simulation Of Difg Unit With Stator Inter-Turn Fault, Boqiang Xu, Liling Sun, Wenjuan Du

Journal of System Simulation

Abstract: The mathematical model of doubly fed induction generator (DFIG) with stator inter-turn fault, which presents itself as standard form state space equation, is deduced and established, for the first time. The corresponding simulation model, i.e. Matlab S-function block is developed and embedded in a Matlab built-in routine simulating DFIG unit comprising wind turbine, converter, related mechanical/electrical control and DFIG. The simulation model of DFIG unit with stator inter-turn fault is established, which is a beneficial extension of Matlab simulation. The stability of DFIG unit under the healthy and faulty conditions is analyzed by using simulation. The results show …

Simulation And Analysis Of Gas Replacement In Sealed Capsule, Xiaohui Guan, Zhou Lin

Journal of System Simulation

Abstract: The multicomponent gas replacement operations in the sealed capsule with cavities connected by slit are modeled and simulated based on the analytic estimation and the CFD numerical simulation methods in this paper. Corresponding result comparisons and discussions on the time costs and replacement effects of different replacement operations and parameters are presented. The estimation and numerical simulation results of mixing and compression replacement operations with different gas velocities demonstrate that, for the cavity connected by slit, analytic estimation method underestimates the effects of mixing replacement operation, but overestimates the compression replacement effects. During the mixing replacement operation, higher …

Mathematical Modeling And Simulation Of Hydraulic Governor For Marine Diesel Engine, Chen Jian

Journal of System Simulation

Abstract: The speed control and load limit of marine diesel engine are implemented by hydraulic governor, of which the characteristics directly determines the performance of generator set. Therefore, it is an important content of marine engine room simulator training to strengthen the students’ training and understanding of the working characteristics of the hydraulic governor. In the existing marine engine room simulators, the simulation model of hydraulic governor is too simple to carry out further training tasks. According to the working principle of hydraulic governor and the training purpose of marine engine room simulator, the mathematical model of UG-8 hydraulic governor …

Evaluation Of Simulation Credibility Based On Rough Set And Gray Correlation Analysis, Huibo Liu, Yongjie Qian

Journal of System Simulation

Abstract: The evaluation of simulation model credibility has always been a hot issue in the simulation field. How to evaluate the credibility of the simulation is the key to the development of the simulation technology. It is of great significance for our country to carry out the credibility evaluation research. In view of the issue, the grey correlation analysis theory and the related principles in rough set theory are analyzed and the simulation credibility evaluation model based on rough set and grey correlation analysis is proposed. The indiscernibility principle in rough set is used to assign the weight distribution of …

Modeling And Simulation Of The Crosstalk On Aircraft Arinc429 Data Bus, Xudong Shi, Ruowen Wang, Jialin Wang, Hongxu Zhao

Journal of System Simulation

Abstract: Based on the theory of multi-conductor transmission line, the crosstalk between a single cable and a UTP (unshielded twisted pairs) cable was studied. The MATLAB and CST were employed to do the theoretical calculation and modeling respectively, and the comparison result proved the validity and accuracy of the proposed model. Based on the UTP model, the shielding layer was used to build the STP（shielded twisted-wire pairs） model according to the ARINC429 specification, and the crosstalk which caused by a large voltage transient happening on the adjacent power line on the aircraft was further analyzed. The distance and length of …

Integrated Berth And Quay Crane Allocation Multi-Objective Algorithm For Container Terminal, Wang Xu, Shixin Liu, Ruiyou Zhang, Wang Jia

Journal of System Simulation

Abstract: This paper researches on a continuous berth and quay crane allocation problem for low carbon container terminal. Considering the constraints of stochastic arrival time and limited truck transportation ability, a multi-objective nonlinear mixed integer programming model is established to minimize carbon emissions and average delay time. An efficient non-dominate sorting genetic algorithm II (ENSGA-II) is designed to deal with this problem. According to the characteristics of the problem, encoding rule and decoding rule based on rolling-horizon simulation, PPX crossover operator with elite selection, multi constraints mutation operator and repair operator are adopted. The results of several simulation experiments …

Simulation Of Taxi Passenger Travel Mode Considering The Influence Of Online Booking Taxi, Cao Yi, Yanjin Li, Luo Xia

Journal of System Simulation

Abstract: To reflect a systematic account of the impact online booking taxi and cruise taxi under the condition of information, the travelling mode choice of taxi passengers was researched. The influence factors of travelling mode choice of taxi passengers were analyzed and the time values related to passenger’s own characteristics were evaluated. The functions of waiting time of online booking taxi passengers and cruise taxi passengers were formed by investigating the difference of searching behavior. Through using simulation method, the priority for online booking taxi, cruise taxi and private cars was obtained .The results showed that the online booking …

Exploring The Variance Of The Sample Variance Through Estimation And Simulation, Christina Stradwick

Theses, Dissertations and Capstones

In this thesis, we examine properties of the variance of the sample variance, which we will denote V (S ² ). We derive a formula for this variance and show that it only depends on the sample size, variance, and kurtosis of the underlying distribution. We also derive the maximum likelihood estimators for this parameter, V^ˆ (S ² ), under the normal, exponential, Bernoulli, and Poisson distributions and end the thesis with simulations demonstrating the distributions of these estimators.

Instability Of Flux Flow And Production Of Vortex-Antivortex Pairs By Current-Driven Josephson Vortices In Layered Superconductors, Ahmad Sheikhzada, Alex Gurevich

Physics Faculty Publications

We report numerical simulations of the nonlinear dynamics of Josephson vortices driven by strong dc currents in layered superconductors. Dynamic equations for interlayer phase differences in a stack of coupled superconducting layers were solved to calculate a drag coefficient η(J) of the vortex as a function of the perpendicular dc current density J. It is shown that Cherenkov radiation produced by a moving vortex causes significant radiation drag increasing η(v) at high vortex velocities v and striking instabilities of driven Josephson vortices moving faster than a terminal v_c. The steady-state flux flow breaks down at ν > v …

Local Lagged Adapted Generalized Method Of Moments: An Innovative Estimation And Forecasting Approach And Its Applications., Olusegun Michael Otunuga, Gandaram S. Ladde, Nathan G. Ladde

Mathematics Faculty Research

In this work, an attempt is made to apply the Local Lagged Adapted Generalized Method of Moments (LLGMM) to estimate state and parameters in stochastic differential dynamic models. The development of LLGMM is motivated by parameter and state estimation problems in continuous-time nonlinear and non-stationary stochastic dynamic model validation problems in biological, chemical, engineering, energy commodity markets, financial, medical, military, physical sciences and social sciences. The byproducts of this innovative approach (LLGMM) are the balance between model specification and model prescription of continuous-time dynamic process and the development of discrete-time interconnected dynamic model of local sample mean and variance statistic …

Virtual Reality And Analysis Framework For Studying Different Layout Designs, Madison Glines

Browse all Theses and Dissertations

This thesis describes the tools for studying different design prototypes. The goal was to develop effective tools to study these designs using a data-driven approach. “Proof of concept” experiments were conducted, in which participants were allowed to interact with a virtual environment depicting different designs as data pertaining to their virtual location and orientation was recorded for later analysis. The designs included “flat” store racks, as opposed to racks with more varied shapes, as well as “curved” racks. Focus of the design studies was to assist in identifying optimal locations for different product types. The automated data collection mechanisms required …

Neuroprotective Effects Of Melatonin And Celecoxib Against Ethanol-Induced Neurodegeneration: A Computational And Pharmacological Approach, Lina T. Al Kury, Alam Zeb, Zain Ul Abidin, Nadeem Irshad, Imran Malik, Arooj Mohsin Alvi, Atif Ali Khan Khalil, Sareer Ahmad, Muhammad Faheem, Arif Ullah Khan, Fawad Ali Shah, Shupeng Li

All Works

© 2019 Al Kury et al. This work is published and licensed by Dove Medical Press Limited. Purpose: Melatonin and celecoxib are antioxidants and anti-inflammatory agents that exert protective effects in different experimental models. In this study, the neuroprotective effects of melatonin and celecoxib were demonstrated against ethanol-induced neuronal injury by in silico, morphological, and biochemical approaches. Methods: For the in silico study, 3-D structures were constructed and docking analysis performed. For in vivo studies, rats were treated with ethanol, melatonin, and celecoxib. Brain samples were collected for biochemical and morphological analysis. Results: Homology modeling was performed to build 3-D …

A Coupled Modeling Framework For Allocation Design In Land-Use And Land-Cover Changes To Optimize Biofuel Feedstock Production, Ana C. Cram

Open Access Theses & Dissertations

Environmental awareness has increased the demand for renewable energy. Notably, the production of biofuels from feedstock is gaining interest as a viable measure to reduce fossil fuels consumption. Nevertheless, it is crucial to identify the trade-offs between bioenergy crop cultivation and the environmental impact on land, water, and atmosphere.

Intensifying biofuel cultivation trigger effects associated with Land Use and Land-use-change, which are complex to assess. While hydrological models had been used to investigate the environmental impacts of land-use changes on water and soil quality, their quantitative assessment is often incomplete. Changes in land use and agricultural activities also contribute to …

Equilibria And Synchrotron Stability In Two Energy Storage Rings, B. Dhital, Jean R. Delayen, Y. S. Derbenev, D. Douglas, Geoffrey A. Krafft, F. Lin, B. Morozov, Y. Zhang

Physics Faculty Publications

In a dual energy storage ring, the electron beam passes through two loops at markedly different energies E_{L}, and E_{H}, i.e., energies for low energy loop and high energy loop respectively. These loops use a common beamline where a superconducting linac at first accelerates the beam from EL to EH and then decelerates the beam from EH to EL in the next pass. There are two basic solutions to the equilibrium problems possible, i.e., ’Storage Ring’ (SR) equilibrium and ’Energy Recovery Linac’ (ERL) equilibrium. SR equilibrium mode more resembles the usual single loop storage ring with strong synchrotron motion and …

Electron-Ion Collider Performance Studies With Beam Synchronization Via Gear-Change, I. Neththikumara, Geoffrey A. Krafft, Y. Roblin, Balša Terzić

Physics Faculty Publications

Beam synchronization of the future electron-ion collider (EIC) is studied with introducing different bunch numbers in the two colliding beams. This allows non-pairwise collisions between the bunches of the two beams and is known as "gear-change", whereby one bunch of the first beam collides with all other bunches of the second beam, one at a time. Here we report on the study of how the beam dynamics of the Jefferson Lab Electron Ion collider concept is affected by the gear change. For this study, we use the new GPU-based code (GHOST). It features symplectic one-turn maps for particle tracking and …