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Articles 56971 - 57000 of 197941

Full-Text Articles in Engineering

Modeling And Quaternion Control Of X-Type Quadrotor, Shaobin Ding, Changshi Xiao, Jingen Liu, Yuanqiao Wen Jul 2020

Modeling And Quaternion Control Of X-Type Quadrotor, Shaobin Ding, Changshi Xiao, Jingen Liu, Yuanqiao Wen

Journal of System Simulation

Abstract: A comprehensive dynamic model of X-type quadrotor was established and simulated. Different from other widely used models that usually treated quadrotor as a single-rigid-body system, the rotors, propellers and the aircraft body were treated as a multi-rigid-body system in the proposed model. The 3D model wireframe was constructed using Solidworks and the important inertial parameters were extracted from the design data. Two types of multi-channel-double-loop vector PD flight controller were designed and fine tuned, one was based on quaternion feedback and the other was based on Euler angle feedback. The close-loop systems were simulated on Matlab/Simulink. The simulation results …


Research On Bifurcation Of A Class Of Cortical Eeg Model With Time Delay, Chunsheng Li, Zhang Xue Jul 2020

Research On Bifurcation Of A Class Of Cortical Eeg Model With Time Delay, Chunsheng Li, Zhang Xue

Journal of System Simulation

Abstract: The bifurcation characters of a cortical-model with bidirectional time delays were studied, proposed by Robinson, et al. before. Considering transmitting delay between excitatory and inhibitory populations, the stability, bifurcation characters and bifurcation region were achieved. The relationship of cortical potential spectrum density and transmit delay was analyzed when white noise was introduced. Result shows that time delay between different population acts as an important role of model’s dynamic characters and stability, and numerical simulation verifies the theoretical analysis. This research shows the importance of transmit delay in cortical-model, and provides theoretical illustration for further research of epileptic …


Research On Damage Ratio Considering Target-Location Error, Xieen Song, Weidong Song, Ma Qian Jul 2020

Research On Damage Ratio Considering Target-Location Error, Xieen Song, Weidong Song, Ma Qian

Journal of System Simulation

Abstract: Different computing methods for target-location error have much influence on the result of cluster target damage ratio. In order to find a suitable method, based on existing damage ratio analytical method and error combination method, several new ideas, such as error synthesis method, random target method, were proposed. By analyzing specific examples and comparing the results, the accuracy and application conditions for each method were reached. Random target method was proved to be the best on the whole; error combination method was optimal when it could meet the conditions of analytical method and data error combination; target-location …


Simulation On Spontaneous Combustion Of Goaf Under “U” Type Ventilation And Improvement, Tiejun Cui, Yundong Ma, Laigui Wang Jul 2020

Simulation On Spontaneous Combustion Of Goaf Under “U” Type Ventilation And Improvement, Tiejun Cui, Yundong Ma, Laigui Wang

Journal of System Simulation

Abstract: To understand the change of temperature and heating area, in different time, in the process of spontaneous combustion of goaf under “U” type ventilation, the model was proposed based on the theory of particle flow. The three basic problems of Oxygen equivalent flow and reaction with the coal were solved, and implemented with FISH. According to the actual working condition, the heating process was simulated, which could be divided into three stages, and the characteristics of the six warming development time were analyzed, finding that the heating area change was related with the oxygen flow in the process of …


Formal Language Constraints In Deep Reinforcement Learning For Self-Driving Vehicles, Tyler Bienhoff Jul 2020

Formal Language Constraints In Deep Reinforcement Learning For Self-Driving Vehicles, Tyler Bienhoff

School of Computing: Dissertations, Theses, and Student Research

In recent years, self-driving vehicles have become a holy grail technology that, once fully developed, could radically change the daily behaviors of people and enhance safety. The complexities of controlling a car in a constantly changing environment are too immense to directly program how the vehicle should behave in each specific scenario. Thus, a common technique when developing autonomous vehicles is to use reinforcement learning, where vehicles can be trained in simulated and real-world environments to make proper decisions in a wide variety of scenarios. Reinforcement learning models, however, have uncertainties in how the vehicle acts, especially in a previously …


Simulation Method Of Ultrasonic Signal Echo From Measured Liquid Level, Li Peng, Xiaolong Shen, Qian Yin Jul 2020

Simulation Method Of Ultrasonic Signal Echo From Measured Liquid Level, Li Peng, Xiaolong Shen, Qian Yin

Journal of System Simulation

Abstract: Based on the ultrasonic wave scattering theory, a simulation method for the ultrasonic signal echo from liquid level was proposed. According to the fluid boundary-layer theory, the liquid level was divided into a four-layer structure, including liquid phase, gas phase, and liquid and gas stagnant layer. Furthermore, every phase was divided into lots of small scatters, and their scattering intensity was set on the basis of the concentration of water molecule. Thus, the echo signal was the sum of reflecting signals from all scatters. Besides, the simulated signal was compared with the real one with the same system parameter …


Study On Lane Keeping Performance With Electric Power Steering System, Sun Tao, Zhengjin Xu, Songlin Zheng, Zhendong Zhang, Yuedong Sun Jul 2020

Study On Lane Keeping Performance With Electric Power Steering System, Sun Tao, Zhengjin Xu, Songlin Zheng, Zhendong Zhang, Yuedong Sun

Journal of System Simulation

Abstract: With consideration of the characteristics of Electric Power Steering system (EPS), vehicle lane keeping system can make full use of EPS function as steering actuator for lane following assist. A couple of vehicle dynamic equations were derived for two operational modes including steering assistant mode and active steering mode. Meanwhile, vehicle single track handling model, nonlinear tire model, driver model, EPS model and corresponding optimal lane tracking algorithm were built and developed respectively. The lane keeping algorithm with EPS actuator was validated by virtue driver-in-the-loop approach based on the EPS experimental map from a certain type of …


Modeling And Simulation For Ultra Supercritical Units Load Regulation By Condensate Throttling, Junjie Gu, Wang Peng Jul 2020

Modeling And Simulation For Ultra Supercritical Units Load Regulation By Condensate Throttling, Junjie Gu, Wang Peng

Journal of System Simulation

Abstract: Dynamic model of the condensate flow and load of ultra supercritical units was given. Reasonable inference and simplified were made by the conservation of volume, conservation of mass and conservation of energy and dynamic model of the condensate flow and load of supercritical units was offered, which could provide theoretical basis for the implement of the power plant condensate throttling and load control. Taking a 1000 MW ultra supercritical unit as an example, simulation of the model was made and compared. Results show that the gain coefficient and the time constant of the transfer function of the condensate …


Simulation Analysis Of Virtual Platform Of Close-Coupling Multiple Robots Combined Lifting System, Su Cheng, Yanlin Wang, Jitao Liu, Zhigang Zhao Jul 2020

Simulation Analysis Of Virtual Platform Of Close-Coupling Multiple Robots Combined Lifting System, Su Cheng, Yanlin Wang, Jitao Liu, Zhigang Zhao

Journal of System Simulation

Abstract: A framework of virtual simulation platform of close-coupling multiple robots combined lifting system was constructed. The model of the multiple robots system was established based on UG. The mathematical model of the mobile robot and the static equilibrium equation of the operated object was established. A collaborative control simulation system was set up based on ADAMS and MATLAB closed loop. In close-coupling multiple robots combined lifting system, according to two different trajectory planning, calculating draw of the mathematical model and the co-simulation model output curves were compared and analyzed to verify the correctness of the mathematical model of the …


Fault Spatial-Temporal Detecting And Diagnosis For Power Grid Based On Wavelet Analysis, Li Gang, Pengcheng Xu, Longmei Han Jul 2020

Fault Spatial-Temporal Detecting And Diagnosis For Power Grid Based On Wavelet Analysis, Li Gang, Pengcheng Xu, Longmei Han

Journal of System Simulation

Abstract: The monitoring data of modern power system have strong intrinsic relationship and its abnormal and fault signal is often hidden in big data sets, so the traditional Fourier transform analysis methods don't have the ability of time domain localization analysis. A new method based on time-frequency characteristics of wavelet analysis was proposed for singularity detection of transient signals in power system, which through decomposing the multi-scale one-dimensional transient signal wavelet, extracted high frequency and low frequency coefficient, and got fault time information while the signal de-noising; then based on the singularity detection of modulus maxima, the fault location information …


Attitude Control Of Vtol Hexrotor Aircraft Based On Lyapunov Theory, Xuemin Yuan, Kecai Cao Jul 2020

Attitude Control Of Vtol Hexrotor Aircraft Based On Lyapunov Theory, Xuemin Yuan, Kecai Cao

Journal of System Simulation

Abstract: The considered hexrotor is a symmetric VTOL-UAV with six rigid mono-directional propellers, and the interval between each propeller is 60°. In order to overcome the inherent geometric singularity of Euler angle description, quaternion representation was used to model. The effect of gyroscopic torques and reactive torques was taken into account when simplifying our model. An approach for hexrotor was proposed in which two nearly equivalent control laws were used to obtain asymptotic stability of attitude angles and attitude angular velocity of the hexrotor UAV. Simulation results emphasize the effectiveness of the proposed control scheme.


Improved Anonymous Communication Protocol Based On Crowds, Gaofeng He, Chen Lu, Zhang Tao, Yuanyuan Ma Jul 2020

Improved Anonymous Communication Protocol Based On Crowds, Gaofeng He, Chen Lu, Zhang Tao, Yuanyuan Ma

Journal of System Simulation

Abstract: The Crowds system is effective and practical, however there are two deficiencies: intermediate nodes can know receivers’ identities and there is no upper bound for the route length. To address the deficiencies mentioned above, an improved anonymous communication protocol is proposed. The new protocol is based on Crowds, while it is added with more designs of Pseudo receiver and Max-Min route length. Pseudo receivers’ addresses substitutes as receivers’ in packets to prevent intermediate nodes getting receivers’ identities; Users can decide max and min route length to limit the route length and meet the anonymity demand. By comparing the …


Pinning Control For Synchronization Of Hr Biological Neural Networks:Linear Active Disturbance Rejection Approach, Wei Wei, Wen Jiao Jul 2020

Pinning Control For Synchronization Of Hr Biological Neural Networks:Linear Active Disturbance Rejection Approach, Wei Wei, Wen Jiao

Journal of System Simulation

Abstract: Synchronization of a complex network whose nodes are Hindmarsh-Rose biological neurons was considered. Coupling strengths of the whole network were always taken as the tuning variables. However, coupling strengths may not be changeable. In addition, synchronization was affected by different disturbances. In view of above factors, pinning control was utilized and linear active disturbance rejection control (LADRC) was designed. By this approach, synchronization was achieved in according to synchronization errors of the controlled nodes and the couplings among nodes. In the simulations, coupling strength was fixed at a relative small value, and no external disturbance case …


Simulation Analysis Of Load Characteristic Of Thin Seam Shearer Drum, Lijuan Zhao, Tian Zhen, Xunan Liu, Xie Bo Jul 2020

Simulation Analysis Of Load Characteristic Of Thin Seam Shearer Drum, Lijuan Zhao, Tian Zhen, Xunan Liu, Xie Bo

Journal of System Simulation

Abstract: In order to analysis the load characteristics of thin seam shearer drum under complex geological conditions, the determination conditions of tooth working state were proposed, the drum load calculation scheme was designed according to the condition of coal seam and the working state of shearer. A thin seam shearer drum as the object of research, the load spectrums of drum under five typical working conditions were calculated, the law of cutting resistance moment and cutting power with different drum revolution speed and haulage speed was analyzed. The results show that: the load fluctuation from cutting hard inclusions is …


Properties Of Terahertz Wave Propagation In Inhomogeneous Plasma Sheath, Jiang Jin, Changxing Chen, Wang Cheng, Ting Chen, Tianxiang Zhou, Yunfei Ling Jul 2020

Properties Of Terahertz Wave Propagation In Inhomogeneous Plasma Sheath, Jiang Jin, Changxing Chen, Wang Cheng, Ting Chen, Tianxiang Zhou, Yunfei Ling

Journal of System Simulation

Abstract: The communication blackout usually happens when the hypersonic vehicles voyage in the near space. According to the data provided by radio attenuation measurement C (RAM C) voyage experiment, two models of inhomogeneous plasma sheath were established after dividing the near space into two spatial layers to build two mathematical models. The principle of interaction between plasma and terahertz wave was analyzed through numerical calculation, getting the properties of terahertz wave propagation in plasma sheath. The simulation shows that the terahertz wave frequency band selected as communication frequency band used in near space can solve the problem of communication blackout. …


A Novel Path Loss Forecast Model To Support Digital Twins For High Frequency Communications Networks, James Marvin Taylor Jr. Jul 2020

A Novel Path Loss Forecast Model To Support Digital Twins For High Frequency Communications Networks, James Marvin Taylor Jr.

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

The need for long-distance High Frequency (HF) communications in the 3-30 MHz frequency range seemed to diminish at the end of the 20th century with the advent of space-based communications and the spread of fiber optic-connected digital networks. Renewed interest in HF has emerged as an enabler for operations in austere locations and for its ability to serve as a redundant link when space-based and terrestrial communication channels fail. Communications system designers can create a “digital twin” system to explore the operational advantages and constraints of the new capability. Existing wireless channel models can adequately simulate communication channel conditions with …


The Influence Of The Reference Area Of Aileron On The N2xx Aircraft Using Computational Fluid Dynamics, Siti Nur Rahmah, Gaguk Jatisukamto, Hary Sutjahjono Jul 2020

The Influence Of The Reference Area Of Aileron On The N2xx Aircraft Using Computational Fluid Dynamics, Siti Nur Rahmah, Gaguk Jatisukamto, Hary Sutjahjono

Journal of Mechanical Engineering Science and Technology (JMEST)

Aileron is a control surface that functions as a regulator of roll motion. The movements of the ailerons are opposite to the left and right sides. Previous studies have shown that graphs of hinge moment coefficient (Chm) values increases with increasing angle of attack. This study is to determine the aerodynamic characteristics of aileron by combining the surface area of the vane into the aileron by varying the aileron’s deflection. The calculation is performed using a numerical method in two dimensions (2D) commercial CFD simulation software. The results of the study concluded that the hinge moment coefficient for modified airfoil …


The Effect Of Heat Treatment To The Erosion Rate Of Brass Composite, Aminnudin Aminnudin, Solichin Solichin Jul 2020

The Effect Of Heat Treatment To The Erosion Rate Of Brass Composite, Aminnudin Aminnudin, Solichin Solichin

Journal of Mechanical Engineering Science and Technology (JMEST)

Brass composites can be improved their mechanical properties by the heat treatment process. The improvement of the mechanical properties of this technique is expected to increase the resistance of the composite to erosion that occurs in the environment of flow water. Brass composites used are compositeswith fly ash 5, 10, 15, and 20%. The heat treatment process was carried out using electric furnace withoutprotective gas. Composite heat up to 350°C and 400°C for 30 min. and quenching with water. Before and after the erosion test, the weight of the test specimen was weighed with analytical scales. The treatment process affects …


Machine Learning Approaches For Fracture Risk Assessment: A Comparative Analysis Of Genomic And Phenotypic Data In 5130 Older Men, Qing Wu, Fatma Nasoz, Jongyun Jung, Bibek Bhattarai, Mira V. Han Jul 2020

Machine Learning Approaches For Fracture Risk Assessment: A Comparative Analysis Of Genomic And Phenotypic Data In 5130 Older Men, Qing Wu, Fatma Nasoz, Jongyun Jung, Bibek Bhattarai, Mira V. Han

School of Public Health Faculty Research

The study aims were to develop fracture prediction models by using machine learning approaches and genomic data, as well as to identify the best modeling approach for fracture prediction. The genomic data of Osteoporotic Fractures in Men, cohort Study (n = 5130), were analyzed. After a comprehensive genotype imputation, genetic risk score (GRS) was calculated from 1103 associated Single Nucleotide Polymorphisms for each participant. Data were normalized and split into a training set (80%) and a validation set (20%) for analysis. Random forest, gradient boosting, neural network, and logistic regression were used to develop prediction models for major osteoporotic fractures …


Synthesizing Expressive Behaviors For Humanoid Robots, Mathias Irwan Sunardi Jul 2020

Synthesizing Expressive Behaviors For Humanoid Robots, Mathias Irwan Sunardi

Dissertations and Theses

Humanoid robots are expected to be able to communicate with expressive gestures at the same level of proficiency as humans. However, creating expressive gestures for humanoid robots is difficult and time consuming due to the high number of degrees of freedom (DOF) and the iterations needed to get the desired expressiveness.

Current robot motion editing software has varying levels of sophistication of motion editing tools ranging from basic ones that are text-only, to ones that provide graphical user interfaces (GUIs) which incorporate advanced features, such as curve editors and inverse kinematics. These tools enable users to create simple motions; but …


Research Review On Mixed-Criticality Scheduling, Hattan Althebeiti Jul 2020

Research Review On Mixed-Criticality Scheduling, Hattan Althebeiti

Recent Advances in Real-Time Systems

No abstract provided.


Environmental Engineering Student Wins Stipend, Usu College Of Engineering Jul 2020

Environmental Engineering Student Wins Stipend, Usu College Of Engineering

College of Engineering News

July 28, 2020 — Utah State University graduate student Jade Snyder Echard will receive a $10,000 stipend from a national organization that encourages students to pursue Master of Science degrees in environmental engineering.


Lignin Valorization In Ionic Liquids And Deep Eutectic Solvent Via Catalysis And Biocatalysis, Jian Shi, Lalitendu Das, Enshi Liu, Joseph C. Stevens Jul 2020

Lignin Valorization In Ionic Liquids And Deep Eutectic Solvent Via Catalysis And Biocatalysis, Jian Shi, Lalitendu Das, Enshi Liu, Joseph C. Stevens

Biosystems and Agricultural Engineering Faculty Patents

This invention relates to a method for extracting valorized compounds from lignin by contacting lignins with an ionic liquid and/or a deep eutectic solvent and adding a catalyst and/or a biocatalyst to assist in breaking down the source material. Converting lignin into high value chemicals adds revenues for a bio-refinery and helps to improve the economic viability of biofuel production.


Enhancing Practical Tractability Of Lyapunov-Based Economic Model Predictive Control, Helen Durand, Dominic Messina Jul 2020

Enhancing Practical Tractability Of Lyapunov-Based Economic Model Predictive Control, Helen Durand, Dominic Messina

Chemical Engineering and Materials Science Faculty Research Publications

Lyapunov-based economic model predictive control (LEMPC) is an optimization-based control design that computes economically-optimal control actions for a process while maintaining the closed-loop state within a bounded region of state-space; however, it may be difficult to design in practice without closed-loop simulations, as it requires an auxiliary stabilizing controller, Lyapunov function, and a number of sets to be developed to ensure closed-loop stability. Practical application of this method could benefit from methods which make it more likely that, without simulations to identify aspects of the control design that would provide stability, controller parameters can be selected that would maintain stability. …


Mitigating Cyberattack Impacts Using Lyapunov-Based Economic Model Predictive Control, Helen Durand, Matthew Wegener Jul 2020

Mitigating Cyberattack Impacts Using Lyapunov-Based Economic Model Predictive Control, Helen Durand, Matthew Wegener

Chemical Engineering and Materials Science Faculty Research Publications

One of the pressing concerns for next-generation manufacturing is the development of techniques for guaranteeing that a control system is cyberattack-resilient in the sense that even if a cyberattack is successful at breaking information technology-based defenses (e.g., it succeeds at providing a false sensor measurement to the controller), closed-loop stability is still maintained. Our prior work has provided a nonlinear systems definition for cyberattacks. This work explores how a nonlinear systems perspective on cyberattack-resilience for false sensor measurements provided to controllers may allow an economic model predictive control (EMPC) formulation known as Lyapunov-based EMPC (LEMPC) to be designed such that …


Lyapunov-Based Economic Model Predictive Control With Taylor Series State Approximations, Keshav Kasturi Rangan, Helen Durand Jul 2020

Lyapunov-Based Economic Model Predictive Control With Taylor Series State Approximations, Keshav Kasturi Rangan, Helen Durand

Chemical Engineering and Materials Science Faculty Research Publications

A method for integrating optimization and control during on-line process operation is known as economic model predictive control (EMPC). EMPC optimizes a general cost function which reflects process economics subject to a model of the process. One formulation of EMPC which can maintain closed-loop stability in the presence of sufficiently small disturbances is Lyapunov-based EMPC (LEMPC). In this work, we make precise connections between closed-loop stability considerations under LEMPC and numerical approximations (via Taylor series) of the solution of the nonlinear dynamic model of the process used in the controller. A chemical process example is utilized to demonstrate the concepts …


A Win For Women In Transportation Engineering, Usu College Of Engineering Jul 2020

A Win For Women In Transportation Engineering, Usu College Of Engineering

College of Engineering News

July 27, 2020—Utah State University graduate student Ferdousy Runa will receive a $4,000 scholarship for her work studying pedestrian activity. Runa's research will help inform transportation planners and lead to safety improvements at busy intersections.


Statistical Modeling Of Historical Daily Water Temperatures In The Lower Columbia River, Malia Hanae Scott Jul 2020

Statistical Modeling Of Historical Daily Water Temperatures In The Lower Columbia River, Malia Hanae Scott

Dissertations and Theses

Water temperature affects numerous aspects of aquatic life, and its stability is critical to cold water fish such as salmonids. With rising anthropogenic influence in natural environments, the future existence of these organisms is becoming less certain. In this study, I examined the evolution of historical water temperatures in the lower Columbia River by creating a statistical model to estimate daily historical water temperatures between the 1850s and 2010s. Daily air temperature and river flow measurements were used as inputs to the model, which estimated daily water temperatures at Bonneville Dam. The model used time lags between air temperature and …


Face Mask Effects Of Co2, Heart Rate, Respiration Rate, And Oxygen Saturation On Instructor Pilots, Andrew R. Dattel, Nicola M. O'Toole, Guillermina Lopez, Kenneth P. Byrnes Jul 2020

Face Mask Effects Of Co2, Heart Rate, Respiration Rate, And Oxygen Saturation On Instructor Pilots, Andrew R. Dattel, Nicola M. O'Toole, Guillermina Lopez, Kenneth P. Byrnes

Publications

The COVID-19 pandemic has required people to take new measures to mitigate the spread of the communicable virus. Guidelines from health organizations, government offices, and universities have been disseminated. Adherence to these guidelines cannot be more critical for flight training. This study explored the effects face masks had on CO2, heart rate, respiration rate, and oxygen saturation while wearing a face mask at an oxygen level simulated to 5,000 feet. Thirty-two instructor pilots (IP) volunteered to participate in the study. IPs spent 90 minutes in a normobaric chamber while wearing a cloth face mask or a paper face mask. Participants …


Secure Networked Control For Decentralized Systems Via Software Rejuvenation, Paul Griffioen, Raffaele Romagnoli, Bruce H. Krogh, Bruno Sinopoli Jul 2020

Secure Networked Control For Decentralized Systems Via Software Rejuvenation, Paul Griffioen, Raffaele Romagnoli, Bruce H. Krogh, Bruno Sinopoli

Faculty Work Comprehensive List

Decentralized control systems exist in many scenarios where agents have the ability to fully communicate with one another but do not do so for multiple reasons, including cost and the possibility of an adversary infiltrating the system through the communication network. In this paper, we present a procedure that determines when agents should communicate with one another after having been disconnected from the network for a period of time. This procedure does not depend on the type of decentralized control system being used. When agents do communicate with one another, we guarantee the safety and resilience of the system against …