Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 60331 - 60360 of 197991

Full-Text Articles in Engineering

Resilient Aircraft Sustainment: Quantifying Resilience Through Asset And Capacity Allocation, Zachary B. Shannon Mar 2020

Resilient Aircraft Sustainment: Quantifying Resilience Through Asset And Capacity Allocation, Zachary B. Shannon

Theses and Dissertations

Decision makers lack a clear, generalizable method to quantify how additional investment in inventory and capacity equates to additional levels of resilience. This research facilitates a deeper understanding of the intricacies and complex interconnectedness of organizational supply chains by monetarily quantifying changes in network resilience. The developed Area under the Curve metric (AUC) is used to quantify the level of demand that each asset allocation can meet during a disruptive event. Due to its applicability across multiple domains, the USAF F-16 repair network in the Pacific theater (PACAF) is modeled utilizing discrete event simulation and used as the illustrating example. …

Go to article

Using A Field Mill Climatology To Assess All Lightning Launch Commit Criteria, Shane C. Gardner Mar 2020

Using A Field Mill Climatology To Assess All Lightning Launch Commit Criteria, Shane C. Gardner

Theses and Dissertations

Due to the danger and cost of lightning striking a space vehicle, the Cape Canaveral Air Force Station (CCAFS) balances between the mission of launching and cessation thereof to minimize the risk of a lightning strike. This process is mediated through a set of rules called the Lightning Launch Commit Criteria (LLCC). To date, no empirical modeling of these rules has been established. To alleviate this shortcoming, this thesis uses the voltage readings of the surrounding CCAFS surface field mills to establish the viability of modeling the entirety of the LLCC rules statistically. Converting approximately 312,000,000 field mill voltage readings …

Go to article

Investigation Of Ultem 9085 For Use In Printed Orbital Structures, William R. Gallagher Mar 2020

Investigation Of Ultem 9085 For Use In Printed Orbital Structures, William R. Gallagher

Theses and Dissertations

Additive manufacturing is revolutionizing industries ranging from medicine to space. However, the structural characteristics of plastic parts created by these methods are not as well understood as their more established counterparts. This research explored two relevant areas: how the structural characteristics of ULTEM 9085 plastic behaved after exposure to orbital conditions and the design of the cross-sectional area of a beam to be 3-D printed in microgravity based on the expected loads from the printer. To study orbital effects, ULTEM 9085 was printed into 1/4th scale ASTM D638- 14 dogbones using a Stratasys 450mc printer. These dogbones were placed in …

Go to article

Timely Near-Optimal Path Generation For An Unmanned Aerial System In A Highly Constrained Environment, Kyle J. Matissek Mar 2020

Timely Near-Optimal Path Generation For An Unmanned Aerial System In A Highly Constrained Environment, Kyle J. Matissek

Theses and Dissertations

A current challenge in path planning is the ability to efficiently calculate a near-optimum path solution through a highly-constrained environment in near-real time. In addition, computing performance on a small unmanned aerial vehicle is typically limited due to size and weight restrictions. The proposed method determines a solution quickly by first mapping a highly constrained three-dimensional environment to a two-dimensional weighted node surface in which the weighting accounts for both the terrain gradient and the vehicle's performance. The 2D surface is then discretized into triangles which are sized based upon the vehicle maneuverability and terrain gradient. The shortest feasible path …

Go to article

Flight Characteristic Verification Of The Variable Camber Compliant Wing, Sharee B. Acosta Mar 2020

Flight Characteristic Verification Of The Variable Camber Compliant Wing, Sharee B. Acosta

Theses and Dissertations

Morphing wing technology gives aircraft the ability to change wing shape to control the aircraft and flight performance characteristics. AFIT, AFRL and USU Aero Lab have collaborated to design and test a variable camber compliant wing (VCCW) on a small unmanned aerial vehicle (UAV). Flight tests demonstrated the wing performance and provided data to refine a VCCW flight simulator. Work was completed with the USU AeroLab-generated MachUp and the actual flight data to improve the simulator to provide results close to those of the actual flight test. The research provides a tool to reduce time and cost for future flight …

Go to article

A Comparative Evaluation Of The Detection And Tracking Capability Between Novel Event-Based And Conventional Frame-Based Sensors, James P. Boettiger Mar 2020

A Comparative Evaluation Of The Detection And Tracking Capability Between Novel Event-Based And Conventional Frame-Based Sensors, James P. Boettiger

Theses and Dissertations

Traditional frame-based technology continues to suffer from motion blur, low dynamic range, speed limitations and high data storage requirements. Event-based sensors offer a potential solution to these challenges. This research centers around a comparative assessment of frame and event-based object detection and tracking. A basic frame-based algorithm is used to compare against two different event-based algorithms. First event-based pseudo-frames were parsed through standard frame-based algorithms and secondly, target tracks were constructed directly from filtered events. The findings show there is significant value in pursuing the technology further.

Go to article

One-Dimensional Multi-Frame Blind Deconvolution Using Astronomical Data For Spatially Separable Objects, Marc R. Brown Mar 2020

One-Dimensional Multi-Frame Blind Deconvolution Using Astronomical Data For Spatially Separable Objects, Marc R. Brown

Theses and Dissertations

Blind deconvolution is used to complete missions to detect adversary assets in space and to defend the nation's assets. A new algorithm was developed to perform blind deconvolution for objects that are spatially separable using multiple frames of data. This new one-dimensional approach uses the expectation-maximization algorithm to blindly deconvolve spatially separable objects. This object separation reduces the size of the object matrix from an NxN matrix to two singular vectors of length N. With limited knowledge of the object and point spread function the one-dimensional algorithm successfully deconvolved the objects in both simulated and laboratory data.

Go to article

Signal Quality Monitoring Of Gnss Signals Using A Chip Shape Deformation Metric, Nicholas C. Echeverry Mar 2020

Signal Quality Monitoring Of Gnss Signals Using A Chip Shape Deformation Metric, Nicholas C. Echeverry

Theses and Dissertations

The Global Navigation Satellite System continues to become deeply em-bedded within modern civilization, and is depended on for confident, accurate navigation information. High precision position and timing accuracy is typically achieved using differential processing, however these systems provide limited compensation for distortions caused by multi-path or faulty satellite hardware. Signal Quality Monitoring (SQM) aims to provide confidence in a receivers Position, Navigation, and Timing solution and to offer timely warnings in the event that signal conditions degrade to unsafe levels. The methods presented in this document focus on implementing effective SQM using low-cost Commercial Off-the-Shelf equipment, a Software Defined Radio, …

Go to article

Alternate Materials For High-Speed Projectile Casing, Andrew W. Beard Mar 2020

Alternate Materials For High-Speed Projectile Casing, Andrew W. Beard

Theses and Dissertations

A high-speed projectile impact is a highly complex dynamic problem that can be simplified with the use of finite element analysis solvers. Abaqus/Explicit was used to evaluate the impact of various projectiles using a plane strain setup. Using a baseline stainless steel projectile, the proposed sandwich construction design was analyzed and compared to the baseline projectile. The overall goal was to see if a new composite casing could perform similarly to the simple baseline projectile. The sandwich construction used stainless steel, tungsten, and silicon-carbide reinforce aluminum as outer and inner shell materials. The core material was created using additive manufacturing …

Go to article

Wind Power Generation Hardware-In-Loop Simulation System Based On Rapid Control Prototype Technology, Aihua Wu, Buhui Zhao, Jingfeng Mao, Haiqun Shen, Xudong Zhang Mar 2020

Wind Power Generation Hardware-In-Loop Simulation System Based On Rapid Control Prototype Technology, Aihua Wu, Buhui Zhao, Jingfeng Mao, Haiqun Shen, Xudong Zhang

Journal of System Simulation

Abstract: In order to improve the efficiency and effectiveness in the design and testing process of the wind power generation MPPT controller, a rapid control prototype (RCP) system based on the LabVIEW FPGA platform is proposed. The real-time simulation model of wind speed, wind turbine and PMSG, as well as MPPT rapid control prototyping are designed by using PXI-FPGA architecture on the LabVIEW RT real-time operation platform. The power converter, the real-time simulation model and the MPPT rapid control prototyping are connected together to construct a hardware-in-loop (HIL) test system. The simulation results on the gradient wind speed condition and …

Go to article

2020 Engineering State Summer Camp Canceled Due To Coronavirus, Usu College Of Engineering Mar 2020

2020 Engineering State Summer Camp Canceled Due To Coronavirus, Usu College Of Engineering

College of Engineering News

News Release—March 25, 2020— In response to the growing concerns about COVID-19, the College of Engineering at Utah State University is canceling its 2020 Engineering State youth summer camp.

Go to article

Learning In The Machine: To Share Or Not To Share?, Jordan Ott, Erik Linstead, Nicholas Lahaye, Pierre Baldi Mar 2020

Learning In The Machine: To Share Or Not To Share?, Jordan Ott, Erik Linstead, Nicholas Lahaye, Pierre Baldi

Engineering Faculty Articles and Research

Weight-sharing is one of the pillars behind Convolutional Neural Networks and their successes. However, in physical neural systems such as the brain, weight-sharing is implausible. This discrepancy raises the fundamental question of whether weight-sharing is necessary. If so, to which degree of precision? If not, what are the alternatives? The goal of this study is to investigate these questions, primarily through simulations where the weight-sharing assumption is relaxed. Taking inspiration from neural circuitry, we explore the use of Free Convolutional Networks and neurons with variable connection patterns. Using Free Convolutional Networks, we show that while weight-sharing is a pragmatic optimization …

Go to article

An Estimation Of Distribution Algorithm Based On Multiple Elites Sampling And Individuals Differential Search, Yu Fei, Ruifeng Wu, Wei Bo, Yinglong Zhang, Xuewen Xia Mar 2020

An Estimation Of Distribution Algorithm Based On Multiple Elites Sampling And Individuals Differential Search, Yu Fei, Ruifeng Wu, Wei Bo, Yinglong Zhang, Xuewen Xia

Journal of System Simulation

Abstract: An estimation distribution algorithm based on the multiple elites sampling and the individuals differential search (EDA-M/D) is proposed. In EDA-M/D, the elites carry out the sampling to generate the offspring independently and enhance the exploration. Meanwhile, the variance of the population distributionis selected to control the sampling radius. Thus, the target of the population can be gradually transited from exploration to exploitation. If the elite population stagnates, the nonentities will choose the mean value of the elites distribution μ and the population historical best solution as the two exemplars to execute a differential search operator, and then help the …

Go to article

Simulation Analysis On Flexible Track Drilling Machine Based On Adams, Yanchao Zhang, Ting Wang, Danlong Song Mar 2020

Simulation Analysis On Flexible Track Drilling Machine Based On Adams, Yanchao Zhang, Ting Wang, Danlong Song

Journal of System Simulation

Abstract: The three-dimensional model of the flexible track drilling machine is designed by the virtual prototyping technology. The model is imported into ADAMS (Automatic Dynamic Analysis of Mechanical Systems) software to carry out the kinematics and dynamic simulation analysis of its virtual prototype, and the rationality and feasibility of the system design are evaluated. Through the comparative analysis, the reasonable driving velocity and acceleration parameters of the hole making system are given. According to the analysis of the dynamic characteristics of the systems, the asymmetric driving problems in the system are found and the corresponding improvement scheme is put forward. …

Go to article

Speech Control Scheme Design And Simulation For Uav Based On Hmm And Rnn, Zhou Nan, Jianliang Ai Mar 2020

Speech Control Scheme Design And Simulation For Uav Based On Hmm And Rnn, Zhou Nan, Jianliang Ai

Journal of System Simulation

Abstract: In order to simplify the operation and avoid the misoperation of UAVs, Based on Hidden Markov Model and Recurrent Neural Networks, a speech control scheme for UAVs is designed. In this scheme, HMM is used to train and recognize the speech command samples of UAVs. HMM is used to pick out the error commands, RNN is used to train the sets of UAVs commands, and the next command based on the training result is predicted. It is determined whether to execute or not by calculating the correlation between commands recognized by HMM and predicted by RNN. The simulation results …

Go to article

Analysis Of Aeroengine Vibration Signal, Pi Jun, Jiaze Chang, Guangcai Liu Mar 2020

Analysis Of Aeroengine Vibration Signal, Pi Jun, Jiaze Chang, Guangcai Liu

Journal of System Simulation

Abstract: Aiming at the analysis of the vibration characteristics of aeroengine rotor, an improved blind source separation algorithm based on cumulant independent component analysis (ICA) is proposed. The new algorithm is used to separate the rotor vibration signal and identify the rotor fault types. The effectiveness of this algorithm is verified by the aeroengine rotor vibration signal simulation. Comparing with the existing algorithms based on second-order cumulants and high-order cumulants, the new method improves the performance index and the signal similarity coefficient. This algorithm is used to separate the vibration signal collected by the engine rotor platform and the rotor …

Go to article

Performance Balanced Opportunistic Routing And Simulation Analysis Based On Cooperative Game, Huahong Ma, Honghai Wu, Guoqiang Zheng, Baofeng Ji Mar 2020

Performance Balanced Opportunistic Routing And Simulation Analysis Based On Cooperative Game, Huahong Ma, Honghai Wu, Guoqiang Zheng, Baofeng Ji

Journal of System Simulation

Abstract: Opportunistic transmission mode of “store-carry-forward” is usually used to make routing in mobile opportunistic network. Currently, there have been many researches in this area. However, the existing opportunistic routing mechanisms pay much attention to the single index of delivery success ratio, but neglect the constraints on other performance indicators, which may lead to the extreme imbalance of network performance. Aiming at this issue, the diffusion of data packets between multiple nodes are modeled as a cooperative game with the goal of maximal performance balancing, and an opportunistic routing protocol based on the cooperative game for performance balancing is proposed. …

Go to article

Maritime Radar Terrain Echo Simulation Based On Dem And Sar, Yongfeng Suo, Shenhua Yang, Guoquan Chen, Zhuqiang Xiang Mar 2020

Maritime Radar Terrain Echo Simulation Based On Dem And Sar, Yongfeng Suo, Shenhua Yang, Guoquan Chen, Zhuqiang Xiang

Journal of System Simulation

Abstract: Due to the huge amount of work required for terrain database building, the application of navigation radar simulation on the reflectivity of land object has been greatly limited. A novel radar simulation method is proposed based on the DEM(Digital Elevation Model) data and the same-band SAR(Synthetic Aperture Radar) reflection data. The target reflectance information is obtained, which is used as the basis for the surface radar reflectivity simulation. In combination with the radar equations, the surface reflectivity model of the navigation radar is established. Taking into account the elevation shielding relationship of the radar echo topography, an algorithm of …

Go to article

System Methodology Of Digital Transformation In Military Manufacturing Industry, Daolin Yu, Wenhai Zhu, Qing Xiao, Guoqiang Shi Mar 2020

System Methodology Of Digital Transformation In Military Manufacturing Industry, Daolin Yu, Wenhai Zhu, Qing Xiao, Guoqiang Shi

Journal of System Simulation

Abstract: Focusing on the lack of the understanding and the solutions to the digital transformation of the military manufacturing enterprises and service providers, the background of the digital transformation in the military manufacturing industry is analyzed. By studying the advanced manufacturing models, the core competitiveness, the value chains and the production (productivity) factors, the (generalization) goals of the digital transformation in the military manufacturing industry are identified, and some urgent problems and the suggestions to solve the complex system problems are provided. The digital transformation in the military manufacturing industry is a long-term strategic action and should be continuously optimized …

Go to article

Research On Emergency Risk Decision Simulation Based On Multi-Agent And Prospect Theory, Wang Jian, Chenqi Situ, Shengqiang Yuan Mar 2020

Research On Emergency Risk Decision Simulation Based On Multi-Agent And Prospect Theory, Wang Jian, Chenqi Situ, Shengqiang Yuan

Journal of System Simulation

Abstract: Focusing on the modeling and the simulation of emergency response risk decision that multi-sections involve in, a simulation model and simulation framework based on multi-agent and prospect theory are proposed. By introducing agent theory, the multi-agent architecture model of emergency risk decision is described and the decision agent are modelled. By introducing prospect theory, following the dynamic evolution of emergencies, the impact of the psychological changes of the decision-makers have on the decision results is studied. The multi-agent emergency risk decision simulation framework is designed and implemented. Taking the risk decision of a fire emergency in the petrochemical plants …

Go to article

Rapid Simulation And Volume Rendering Of Electromagnetic Environment Based On Geographic Coordinate System, Yuguo Wu, Beibei Han Mar 2020

Rapid Simulation And Volume Rendering Of Electromagnetic Environment Based On Geographic Coordinate System, Yuguo Wu, Beibei Han

Journal of System Simulation

Abstract: Considering the earth's curvature, the spherical regular grid model is used to organize the electromagnetic field data. In order to reduce computational complexity of ITM model, the terrain reuse is proposed to improve the efficiency of the simulation. The Multithread and the terrain reuse are combined to improve the efficiency of the multi-radiation source. Considering that the traditional ray casting algorithm which takes the cube model as the bounding box cannot draw spherical regular grid data directly, a ray casting algorithm which uses the dome model as the bounding box is proposed. Experiments show that even considering the influence …

Go to article

Spatial Structure Optimization Of Natural Forest Based On Bee Colony-Particle Swarm Algorithm, Dongsheng Qing, Xiaofang Zhang, Jianjun Li, Guo Rui, Qiaoling Deng Mar 2020

Spatial Structure Optimization Of Natural Forest Based On Bee Colony-Particle Swarm Algorithm, Dongsheng Qing, Xiaofang Zhang, Jianjun Li, Guo Rui, Qiaoling Deng

Journal of System Simulation

Abstract: The natural forest spatial structure contains the spatial location information of the forest, which affects the growth, competition and stability of the forest development. Its optimization is a multi-objective programming problem. A bee colony particle swarm optimization (ABC-PSO) hybrid algorithm is proposed, which improves the initial particle generation mechanism, the number of follow bees and the circulation mechanism. The algorithm is applied to the multi-objective optimization of the spatial structure of natural forest. An optimization model which takes account of the tree distribution grid, tree size segmentation and tree competition is established. The simulation results show that the bee …

Go to article

Research On Evolution Model Of Online Public Opinion Based On Temporal Network, Li Feng, Wei Ying Mar 2020

Research On Evolution Model Of Online Public Opinion Based On Temporal Network, Li Feng, Wei Ying

Journal of System Simulation

Abstract: With the in-depth study on the social medias, the social networks of online platforms are recognized gradually as the time-varying temporal networks. In order to compare and analyze the information diffusion process and the result, the analysis method of computer simulations is adopted, a temporal network is generated, and the SIR model is used as the online public opinion diffusion model. The simulation results based on multi-agent approach show that the uncertainty of information diffusion on the social platforms comes from the complicated structure of the temporal networks and the SIR model. In addition, the misunderstanding of the social …

Go to article

Multi-Uav 3d Formation Path Planning Based On Improved Artificial Potential Field, Haiyun Chen, Huazhou Chen, Liu Qiang Mar 2020

Multi-Uav 3d Formation Path Planning Based On Improved Artificial Potential Field, Haiyun Chen, Huazhou Chen, Liu Qiang

Journal of System Simulation

Abstract: Focusing on the GNRON (goal nonreachable with obstacles nearby), the local minima and chattering of the traditional artificial potential field method, the potential field functions are improved and analyzed to guarantee the goal is the global minimum. In the dynamic potential field, a mechanism of judging whether to fall into local minima is introduced, a method of “moving along the orientation of 90° of goal direction” is used to jump out of the local minima, and the path planning of multi-UAV formation, the synergistic obstacle avoidance and collision prevention are achieved. The path is optimized by applying the regression …

Go to article

Parallel Computing Of Multi-Agent System In Spatially-Explicit Modeling And Simulation, Hongchun Qu, Xianhui Yao, Yin Li Mar 2020

Parallel Computing Of Multi-Agent System In Spatially-Explicit Modeling And Simulation, Hongchun Qu, Xianhui Yao, Yin Li

Journal of System Simulation

Abstract: Aiming at the synchronization in the spatially-explicit parallel simulations, a limited optimistic synchronization algorithm based on Agent sensing region is proposed. The algorithm inherits the advantages of the optimistic synchronization algorithm and the security-guaranteed conservative synchronization algorithm. The algorithm categories all simulated agents into the security agent region and non-security agent region. The simulation is performed through the collaboration between the dispatch server and the execution servers where simulation tasks are scheduled and executed. The dispatch server determines whether an agent is in a security zone according to the security radius. The execution servers are responsible for performing the …

Go to article

Visualization Of Tropical Cyclones Based On Digital Earth, Shuoben Bi, Yucheng Gong, Mingyue Lu, Zhou Hao, Tang Zhi Mar 2020

Visualization Of Tropical Cyclones Based On Digital Earth, Shuoben Bi, Yucheng Gong, Mingyue Lu, Zhou Hao, Tang Zhi

Journal of System Simulation

Abstract: Tropical cyclones are often accompanied by heavy rains, storm surges and so on, which have serious impact on the southeast coast of China. Visualization of tropical cyclones can directly demonstrate its motion state, occurrence process and internal structure, and support the research and prediction on it. This paper builds digital earth platform based on Cesium(an open source library),introduces the system architecture, verificates the applicability of point cloud method to the visualization of cloud field data, proposes an improved wind field visualization method based on particle tracking, with includes the calculation of wind field particle properties, the drawing of wind …

Go to article

Emergency Evacuation Simulation For Dense Passenger Flow In A Rail Transit Transfer Station, Xu Hui, Tian Cheng, Wang Yong Mar 2020

Emergency Evacuation Simulation For Dense Passenger Flow In A Rail Transit Transfer Station, Xu Hui, Tian Cheng, Wang Yong

Journal of System Simulation

Abstract: The rail transit is one of the important modes of the public transportation, and its safety operation is crucial. Based on the passenger volume and structure features that have been obtained through the field investigation in Chongqing Lianglukou railway station in China, a multi-level rail transit transfer station simulation model is built to analyze the evacuation process of pedestrians in the consideration of explosion and other emergencies by the software AnyLogic. The evacuation routes and evacuation time of passengers during emergency evacuation in a rail transit transfer station are studied. The research aims at verifying the emergency evacuation capacity …

Go to article

Optimization Simulation Of Feeder Airport Runway Structure For Pollutant Discharge Control, Jiang Bo, Yunfan Zhou, Chenglong Li, Zhang Hao Mar 2020

Optimization Simulation Of Feeder Airport Runway Structure For Pollutant Discharge Control, Jiang Bo, Yunfan Zhou, Chenglong Li, Zhang Hao

Journal of System Simulation

Abstract: Air pollutant discharge in the LTO (Landing and Take-off) cycle of the civil aviation transport is harmful to the ground personnel and the near-ground environment, which can be restrained primarily by reducing the ground taxi time. Considering the structure of the single-taxiway-single-runway in the common feeder airport, a method for calculating the aircraft ground taxi time is presented. Based on this method, an evaluation index of the pollutants is proposed and an assessment model of aircraft pollutants emission in feeder airport is established. Taking a feeder airport as an example, the taxiway crossing position with the smallest pollutant evaluation …

Go to article

Model Of Initial Spare Parts Configuration And Ordering Policy Optimization Based On Inventory State, Songshi Shao, Minzhi Ruan, Zhihua Zhang Mar 2020

Model Of Initial Spare Parts Configuration And Ordering Policy Optimization Based On Inventory State, Songshi Shao, Minzhi Ruan, Zhihua Zhang

Journal of System Simulation

Abstract: Rational planning of spare parts configuration project is an effective approach to improve the equipment availability and reduce the life cycle cost (LCC). First of all, the spare parts demand rate forecast model is constructed. According to the systemic analysis method, the spare parts support effectiveness evaluation targets system is built, and then, the initial spare parts configuration optimization method is researched. Aim to the consumption for partial repairable spare parts, the expected backorders function of the approximate Laplace demand distribution is given. Combining the (s-1, s) and (R, Q) inventory policy, the ordering model is established under the …

Go to article

Research On Building Mechanism Model Simulation In Energy-Saving Control, Bai Yang, Decheng Yuan, Li Ling Mar 2020

Research On Building Mechanism Model Simulation In Energy-Saving Control, Bai Yang, Decheng Yuan, Li Ling

Journal of System Simulation

Abstract: In the existing building system, the energy consumption is huge, the control system is complex, and the electricity cost is high. In order to reduce the cost of electricity, the mechanism model of the building is established for simulation. The accuracy of the model is verified by simulation to confirm the model applicability to the building system. Comparing the constant electricity price with the time-varying electricity price, the system under the model predictive control can response to the price change of electricity with time and can achieve the cost control and energy-saving.

Go to article

First Prev Next Last