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Full-Text Articles in Numerical Analysis and Scientific Computing

Spatial Spectrum Estimation Method Of Flank Twin-Line Array Based On Cross-Spectrum Correlation, Zhizhong Li, Wang Sen, Zhongliang Xu, Weiguo Dai, Qijun Liu Nov 2019

Spatial Spectrum Estimation Method Of Flank Twin-Line Array Based On Cross-Spectrum Correlation, Zhizhong Li, Wang Sen, Zhongliang Xu, Weiguo Dai, Qijun Liu

Journal of System Simulation

Abstract: Considering the structural features of the flank twin-line array, researches on spatial spectrum estimation of twin-line array based on adaptive beam-forming and cross-spectrum correlation were carried out. A spatial spectrum estimation method based on cross-spectrum correlation is proposed according to the theory of cross-spectrum. The study of spectrum estimation performance comparison of the twin-line array was finished by that method combined with the conventional beam-forming and the adaptive beam-forming respectively. The results prove that the method based on cross-spectrum correlation has a better capability in noise suppression; and the method, which combined adaptive beam-forming with cross-spectrum correlation, is the …


Influence Of Composite Materials Surface Metal Mesh On Helicopter Lightning Stroke Effects, Junling Huang, Jiayu Xie Nov 2019

Influence Of Composite Materials Surface Metal Mesh On Helicopter Lightning Stroke Effects, Junling Huang, Jiayu Xie

Journal of System Simulation

Abstract: The metal wire mesh is usually adopted to prevent the lightning stroke on composite materials. The effects of different materials and different thickness of metal mesh on helicopter lightning electromagnetic effect are compared. According to the method recommended by SAE-ARP5416, a numerical simulation software is used for carrying out the high current injection simulation. The results show that the surface mount metal mesh can effectively reduce the harm of lightning electromagnetic coupling effect; the difference between aluminum and copper on anti-lightning stroke effect is not obvious; when the thickness of aluminum grid is less than 0.15 mm, the …


Thai Language Names, Place Names And Organization Names Entity Recognition, Hongbin Wang, Hongkui Gao, Shen Qiang, Yantuan Xian Nov 2019

Thai Language Names, Place Names And Organization Names Entity Recognition, Hongbin Wang, Hongkui Gao, Shen Qiang, Yantuan Xian

Journal of System Simulation

Abstract: Named entity recognition in Thai language is aimed to identify the names of a person, a locality,an organization or an institution,and so on. Due to the complexity of Thai word formation method and grammar rules, to solve this problem, the idea of the approach proposed is to treat the task of named entity recognition in Thai language as labeling the sign of a series of words in Thai sentence. Given the characteristics of Thai language itself, certain features in the context of the samples in the Thai entity recognition corpus are extracted to train the hidden Markov model and …


Multi-Seats Collaborative Task Planning Based On Improved Particle Swarm Optimization, Cai Rui, Wang Wei, Jue Qu, Hu Bo Nov 2019

Multi-Seats Collaborative Task Planning Based On Improved Particle Swarm Optimization, Cai Rui, Wang Wei, Jue Qu, Hu Bo

Journal of System Simulation

Abstract: Aiming at the allocation conflict between task and operator of multi-seats collaborative task planning in command and control cabin, a multi-seats collaborative task planning method based on improved particle swarm optimization is proposed. This method describes and analyzes the multi-seats collaborative task and establishes a solution space model based on task sequence. In solving the model, the particle swarm optimization (PSO) was improved by using multi-dimensional asynchronous processing and modifying inertia weight parameters so that the efficiency and local searching ability of the PSO were improved. The example analysis shows that the model and the algorithm can effectively reduce …


High-Dimensional Clustering Method Based On Variant Bat Algorithm, Kou Guang, Guangming Tang, Jiajing He, Hengwei Zhang Nov 2019

High-Dimensional Clustering Method Based On Variant Bat Algorithm, Kou Guang, Guangming Tang, Jiajing He, Hengwei Zhang

Journal of System Simulation

Abstract: With the advent of the era of big data, the information resource is growing rapidly, and the data are becoming high-dimensional. Traditional clustering methods have a good effect for low-dimensional data, but no longer apply to high-dimensional data. On the basis of existing high-dimensional clustering algorithm, a high-dimensional clustering algorithm based on intelligent optimization SSC-BA is proposed. A novel objective function is designed, which integrates the fuzzy weighting within-cluster compactness and the between-cluster separation. A variant bat algorithm is introduced to calculate the weight matrix, giving the new learning rules. Simulation experiments are made for the proposed algorithm, and …


Stressmon: Scalable Detection Of Perceived Stress And Depression Using Passive Sensing Of Changes In Work Routines And Group Interactions, Nur Camellia Binte Zakaria, Rajesh Balan, Youngki Lee Nov 2019

Stressmon: Scalable Detection Of Perceived Stress And Depression Using Passive Sensing Of Changes In Work Routines And Group Interactions, Nur Camellia Binte Zakaria, Rajesh Balan, Youngki Lee

Research Collection School Of Computing and Information Systems

Stress and depression are a common affliction in all walks of life. When left unmanaged, stress can inhibit productivity or cause depression. Depression can occur independently of stress. There has been a sharp rise in mobile health initiatives to monitor stress and depression. However, these initiatives usually require users to install dedicated apps or multiple sensors, making such solutions hard to scale. Moreover, they emphasise sensing individual factors and overlook social interactions, which plays a significant role in influencing stress and depression while being a part of a social system. We present StressMon, a stress and depression detection system that …


Mathematics And Programming Exercises For Educational Robot Navigation, Ronald I. Greenberg Jul 2019

Mathematics And Programming Exercises For Educational Robot Navigation, Ronald I. Greenberg

Computer Science: Faculty Publications and Other Works

This paper points students towards ideas they can use towards developing a convenient library for robot navigation, with examples based on Botball primitives, and points educators towards mathematics and programming exercises they can suggest to students, especially advanced high school students.


Implementation Of Multivariate Artificial Neural Networks Coupled With Genetic Algorithms For The Multi-Objective Property Prediction And Optimization Of Emulsion Polymers, David Chisholm Jun 2019

Implementation Of Multivariate Artificial Neural Networks Coupled With Genetic Algorithms For The Multi-Objective Property Prediction And Optimization Of Emulsion Polymers, David Chisholm

Master's Theses

Machine learning has been gaining popularity over the past few decades as computers have become more advanced. On a fundamental level, machine learning consists of the use of computerized statistical methods to analyze data and discover trends that may not have been obvious or otherwise observable previously. These trends can then be used to make predictions on new data and explore entirely new design spaces. Methods vary from simple linear regression to highly complex neural networks, but the end goal is similar. The application of these methods to material property prediction and new material discovery has been of high interest …


Geometric Top-K Processing: Updates Since Mdm'16 [Advanced Seminar], Kyriakos Mouratidis Jun 2019

Geometric Top-K Processing: Updates Since Mdm'16 [Advanced Seminar], Kyriakos Mouratidis

Research Collection School Of Computing and Information Systems

The top-k query has been studied extensively, and is considered the norm for multi-criteria decision making in large databases. In recent years, research has considered several complementary operators to the traditional top-k query, drawing inspiration (both in terms of problem formulation and solution design) from the geometric nature of the top-k processing model. In this seminar, we will present advances in that stream of work, focusing on updates since the preliminary seminar on the same topic in MDM'16.


Fluid Transport In Porous Media For Engineering Applications, Eric M. Benner May 2019

Fluid Transport In Porous Media For Engineering Applications, Eric M. Benner

Chemical and Biological Engineering ETDs

This doctoral dissertation presents three topics in modeling fluid transport through porous media used in engineering applications. The results provide insights into the design of fuel cell components, catalyst and drug delivery particles, and aluminum- based materials. Analytical and computational methods are utilized for the modeling of the systems of interest. Theoretical analysis of capillary-driven transport in porous media show that both geometric and evaporation effects significantly change the time dependent behavior of liquid imbibition and give a steady state flux into the medium. The evaporation–capillary number is significant in determining the time-dependent behavior of capillary flows in porous media. …


Depressiongnn: Depression Prediction Using Graph Neural Network On Smartphone And Wearable Sensors, Param Bidja May 2019

Depressiongnn: Depression Prediction Using Graph Neural Network On Smartphone And Wearable Sensors, Param Bidja

Honors Scholar Theses

Depression prediction is a complicated classification problem because depression diagnosis involves many different social, physical, and mental signals. Traditional classification algorithms can only reach an accuracy of no more than 70% given the complexities of depression. However, a novel approach using Graph Neural Networks (GNN) can be used to reach over 80% accuracy, if a graph can represent the depression data set to capture differentiating features. Building such a graph requires 1) the definition of node features, which must be highly correlated with depression, and 2) the definition for edge metrics, which must also be highly correlated with depression. In …


The Effects Of Finite Precision On The Simulation Of The Double Pendulum, Rebecca Wild May 2019

The Effects Of Finite Precision On The Simulation Of The Double Pendulum, Rebecca Wild

Senior Honors Projects, 2010-2019

We use mathematics to study physical problems because abstracting the information allows us to better analyze what could happen given any range and combination of parameters. The problem is that for complicated systems mathematical analysis becomes extremely cumbersome. The only effective and reasonable way to study the behavior of such systems is to simulate the event on a computer. However, the fact that the set of floating-point numbers is finite and the fact that they are unevenly distributed over the real number line raises a number of concerns when trying to simulate systems with chaotic behavior. In this research we …


Visualization And Machine Learning Techniques For Nasa’S Em-1 Big Data Problem, Antonio P. Garza Iii, Jose Quinonez, Misael Santana, Nibhrat Lohia May 2019

Visualization And Machine Learning Techniques For Nasa’S Em-1 Big Data Problem, Antonio P. Garza Iii, Jose Quinonez, Misael Santana, Nibhrat Lohia

SMU Data Science Review

In this paper, we help NASA solve three Exploration Mission-1 (EM-1) challenges: data storage, computation time, and visualization of complex data. NASA is studying one year of trajectory data to determine available launch opportunities (about 90TBs of data). We improve data storage by introducing a cloud-based solution that provides elasticity and server upgrades. This migration will save $120k in infrastructure costs every four years, and potentially avoid schedule slips. Additionally, it increases computational efficiency by 125%. We further enhance computation via machine learning techniques that use the classic orbital elements to predict valid trajectories. Our machine learning model decreases trajectory …


New Clock-Driven Algorithm Based On Separation Of Synaptic Conductance Computation, Zhijie Wang, Peng Xia, Han Fang, Xiaochun Gu Apr 2019

New Clock-Driven Algorithm Based On Separation Of Synaptic Conductance Computation, Zhijie Wang, Peng Xia, Han Fang, Xiaochun Gu

Journal of System Simulation

Abstract: In order to reduce the computing time when simulating the biologic neural network, an efficient clock-driven algorithm based on the separation of synaptic conductance computation is presented. It is found that the calculation of the synaptic state variables can be separated into two independent parts: one called conductance coefficient related with the pre-synaptic neuron, and the other called synaptic current. By introducing the data structure of the virtual synapse cluster to storing sequences of synaptic conductance coefficient, the former part can be calculated independently according to the spiking states of pre-synaptic neuron at each time step. When calculating the …


Grasping Simulation Of Linkage Underactuated Mechanical Finger, Xiali Li, Tianyi Lan, Licheng Wu Apr 2019

Grasping Simulation Of Linkage Underactuated Mechanical Finger, Xiali Li, Tianyi Lan, Licheng Wu

Journal of System Simulation

Abstract: For verifying the design rationality and the property of a linkage underactuated finger, Solidworks is utilized to simulate the grasp operation of the finger with some different objects at the different positions. The simulations can be used to analyze the grasping range, the underactuated characteristic, the uniformity of grasp motion and the mechanical property. The finger mechanism contains springs that brings adaptive grasp capability of different objects. The results show that the finger can make suitable capability for grasping the objects whose size can vary from 0.106 to 0.851 times of the finger length. And the finger can give …


Modeling And Simulation Of False Report Filtering Scheme Based On Position In Wireless Sensor Networks, Zhixiong Liu, Limiao Li Apr 2019

Modeling And Simulation Of False Report Filtering Scheme Based On Position In Wireless Sensor Networks, Zhixiong Liu, Limiao Li

Journal of System Simulation

Abstract: In wireless sensor networks, the adversary can inject false reports from compromised nodes. Previous security designs cannot detect faked reports that are forged coordinately by a group of compromised nodes. Furthermore, in sparse areas, some events failed to be reported to sink. This paper proposes a position based filtering scheme (PFS). It derives the optimal coverage degree ω, and the nodes are deployed accordingly. After deployment, each node distributes its position to some other nodes. When a report is generated for an observed event, it must carry t distinct MACs (Message Authentication Codes) along with positions of all detecting …


Multi-Chromosome Genetic Algorithm For Multiple Traveling Salesman Problem, Duofu Ye, Liu Gang, He Bing Apr 2019

Multi-Chromosome Genetic Algorithm For Multiple Traveling Salesman Problem, Duofu Ye, Liu Gang, He Bing

Journal of System Simulation

Abstract: A multi-traveling salesman model with time window is established, and two objective functions for the number of traveling salesmen and the sum of travel time are designed. A multi - chromosome coding method is designed to develop complex mutation operator tree, which overcomes the problem of large searching space of traditional genetic algorithms. The performances of algorithms are compared by simulation, and the simulation results show that the genetic algorithm with complex multi-chromosome mutation tree can balance the two objective functions of the number of TSP and total travel time well, improve the algorithm of travel speed, and reduce …


Virtual Scene Simulation Of Pilot Response In Taking-Off And Landing Processes Of Carrier-Based Aircraft, Ke Peng, Chenglin Xu, Songyang Liu, Minggao Li, Zhao Xin Apr 2019

Virtual Scene Simulation Of Pilot Response In Taking-Off And Landing Processes Of Carrier-Based Aircraft, Ke Peng, Chenglin Xu, Songyang Liu, Minggao Li, Zhao Xin

Journal of System Simulation

Abstract: A research and implementation method based on biomechanics simulation and virtual scene simulation was put forward to investigate the dynamics responses of pilots during the taking off and landing processes of carrier-based aircraft. The human biomechanics calculation of pilots and 3D virtual scene simulation of flight scene were combined to design and develop the integrated virtual simulation platform. This platform has the functions of data management and analysis, human biological dynamics calculation, synchronous analysis of key results, 3D virtual scene simulation of taking-off and landing processes and human response. The verification was carried out using the experiments from …


Modeling And Timing Simulation Of Turbojet Engine Starting Process, Wang Lei, Liying Yang, Hongda Zhang, Yuqing He Apr 2019

Modeling And Timing Simulation Of Turbojet Engine Starting Process, Wang Lei, Liying Yang, Hongda Zhang, Yuqing He

Journal of System Simulation

Abstract: The turbojet engine is complicated in its starting process and requires collaboration and cooperation involving all the execution structures, thus higher demand is put forward for the control system. How to model the engine starting process, and then accurately describe and analyze the impact of actuator states on engine performance directly affect the engine control system performance. According to the working principle of the JetCat-P400 German turbojet starting process, the rotor speed mathematical model of the turbojet engine starting process is constructed by the component method. The parameters of the model are identified by combining the experimental data of …


Wind Speed Noise Reduction In Wind Farm Based On Variational Mode Decomposition, Xinghua Xu, Tinglong Pan, Dinghui Wu Apr 2019

Wind Speed Noise Reduction In Wind Farm Based On Variational Mode Decomposition, Xinghua Xu, Tinglong Pan, Dinghui Wu

Journal of System Simulation

Abstract: Wind power forecast is based on the existing data, and the wind speed data in wind power are mixed with different types of noise. In order to improve the precision of prediction, noise reduction is needed. However, the traditional empirical mode decomposition noise reduction method has the phenomenon of mode mixing. To improve the effect of the noise reduction, a kind of noise reduction method based on variational mode decomposition is proposed. The variational mode decomposition is a new method which has good noise immunity and no mode mixing. To thoroughly research the application of variational mode decomposition …


Predictive Control For Permanent Magnet Synchronous Motor Based On Imc Observer, Zhiling Ren, Zhongbao Zhang, Limin Hou, Guangquan Zhang, Lin Dong, Zhao Xing Apr 2019

Predictive Control For Permanent Magnet Synchronous Motor Based On Imc Observer, Zhiling Ren, Zhongbao Zhang, Limin Hou, Guangquan Zhang, Lin Dong, Zhao Xing

Journal of System Simulation

Abstract: Predictive control strategy is applied to permanent magnet synchronous motor control system, it can achieve fast dynamic response and high-precision tracking control, but depending on the mathematical model of the motor, the load disturbance will affect the control performance of system. A new control method combining an observer based on internal model control (IMC) and predictive control was presented. The inner-loop current controller and the outer-loop speed controller based separately on model predictive control algorithm and deadbeat current predictive control algorithm were designed to form dual-loop predictive control system. An IMC observer is designed to estimate the load disturbance, …


Distribution Routing Optimization Of Fresh Agricultural Products Based On Road Conditions, Wang Heng, Yaxing Xu, Zhenfeng Wang, Tianpeng Zhou, Dechun Tian Apr 2019

Distribution Routing Optimization Of Fresh Agricultural Products Based On Road Conditions, Wang Heng, Yaxing Xu, Zhenfeng Wang, Tianpeng Zhou, Dechun Tian

Journal of System Simulation

Abstract: Reasonable arrangement of distribution route of fresh agricultural product can effectively guarantee the freshness of products, improve the distribution efficiency, and reduce the distribution cost. In practical distribution, the road condition is an important factor affecting the arrangement of the distribution route. According to the different road conditions, the speed characteristic models are set up. Meanwhile, considering the perishable and vulnerable characteristics of fresh agricultural products, the function of time window penalty cost and the function of customer satisfaction are established. Based on the comprehensive consideration of factors, such as road condition, time window and fresh consumption, a multi-objective …


Simulation Of Domestic Hot Water Using Behavior Of College Students Based On Group Characteristics, Zhou Jin, Xiaoping Yin, Xu Feng Apr 2019

Simulation Of Domestic Hot Water Using Behavior Of College Students Based On Group Characteristics, Zhou Jin, Xiaoping Yin, Xu Feng

Journal of System Simulation

Abstract: The use of domestic hot water is influenced by user’s gender and living habits, so the composition and behavior characteristics of user group have great influence on the design and operation control of domestic hot water system. The classification of hot water user group of college students was made by means of statistical analysis of original data, and the parameters related to the probability distributions of hot water use behavior were obtained. The simulation of domestic hot water using by college students was conducted and compared with the data generated from original recorded data, and the results show good …


Evaluation Of Green Smart Cities In China Based On Entropy Weight - Cloud Model, Chen Li, Haixia Zhang Apr 2019

Evaluation Of Green Smart Cities In China Based On Entropy Weight - Cloud Model, Chen Li, Haixia Zhang

Journal of System Simulation

Abstract: Based on the research on green smart city at home and abroad; and aiming at the shortcomings and deficiencies of traditional evaluation methods, this paper proposes an evaluation method of combining entropy and cloud model based on the cloud model which can realize the conversion of qualitative concept and quantitative value. This method synthetically considers the subjective and objective factors; carries on the correlation analysis to the index; determines the set of evaluation indicators; uses the X-conditional cloud generator in cloud model to obtain the different levels of membership matrix corresponding to each evaluation object; and carries on the …


Image Feature Extraction And Online Grading Method For Weight And Shape Of Strawberry, Zhang Qing, Xiangjun Zou, Guichao Lin, Yanhui Sun Apr 2019

Image Feature Extraction And Online Grading Method For Weight And Shape Of Strawberry, Zhang Qing, Xiangjun Zou, Guichao Lin, Yanhui Sun

Journal of System Simulation

Abstract: To deal with the classification problems of strawberry in production, a machine vision based strawberry weight and shape grading method was proposed. The strawberry image was segmented by thresholding to extract the fruit. The area and perimeter parameters of the fruit were then calculated and used to build the strawberry weight grading model through regression analysis. Elliptic Fourier descriptor was used to extract the shape features of the fruit, and these shape features were applied to train a support vector machine (SVM) which represented the strawberry shape grading model. 200 samples of strawberries were selected to test both …


Dp-Q(Λ): Real-Time Path Planning For Multi-Agent In Large-Scale Web3d Scene, Fengting Yan, Jinyuan Jia Apr 2019

Dp-Q(Λ): Real-Time Path Planning For Multi-Agent In Large-Scale Web3d Scene, Fengting Yan, Jinyuan Jia

Journal of System Simulation

Abstract: The path planning of multi-agent in an unknown large-scale scene needs an efficient and stable algorithm, and needs to solve multi-agent collision avoidance problem, and then completes a real-time path planning in Web3D. To solve above problems, the DP-Q(λ) algorithm is proposed; and the direction constraints, high reward or punishment weight training methods are used to adjust the values of reward or punishment by using a probability p (0-1 random number). The value from reward or punishment determines its next step path planning strategy. If the next position is free, the agent could walk to it. The above strategy …


Design And Realization Of Ship Virtual Fire Training System Based On Hmd, Zhang Bo, Sun Jun, Shang Lei, Hongji Xu, Yang Cheng Apr 2019

Design And Realization Of Ship Virtual Fire Training System Based On Hmd, Zhang Bo, Sun Jun, Shang Lei, Hongji Xu, Yang Cheng

Journal of System Simulation

Abstract: Aiming at the shortcomings of ship fire training in real environment and the advantages and application of virtual reality technology in education and training, the virtual fire training system of ship based on head mount display (HMD) is developed. The system is developed using the Unity 3D Virtual Reality Development Engine as a platform, using client / server mode, supporting multi-person cooperative operation, and running the terminal for HTC Vive virtual reality hardware. The system combines the fire diffuser mechanism, the water shooting hydrodynamic equation and the particle system; completes the model establishment and visualization process, and improves …


Systematic Error Analysis Based On Hardware-In-The-Loop Simulation Environment, Zhang Duo, Manguo Liu, Zhang Xiao, Pingan Liu, Yixuan He Apr 2019

Systematic Error Analysis Based On Hardware-In-The-Loop Simulation Environment, Zhang Duo, Manguo Liu, Zhang Xiao, Pingan Liu, Yixuan He

Journal of System Simulation

Abstract: Aiming at the complex and diverse components in the semi-physical simulation environment of a certain type of anti-tank missile, the errors present different types of problems, and a systematic error analysis method based on the environment is proposed. By analyzing the composition characteristics and the error characteristics of the simulation computer, flight motion simulator, target simulator and simulation dedicated interface; the delay error of the simulation computer, the mechanical installation error of the flight motion simulator, the delay error of the target simulator and the transmission error of the simulation dedicated interface are acquired. Furthermore, by comparing the local …


Design And Simulation Of Heterogeneous Magnetron Memristive Chua Circuit, Xiaohong Zhang, Lijuan Wan, Keliu Long Apr 2019

Design And Simulation Of Heterogeneous Magnetron Memristive Chua Circuit, Xiaohong Zhang, Lijuan Wan, Keliu Long

Journal of System Simulation

Abstract: A nonlinear circuit containing two heterogeneous magnetron memristors which based on the three-order classic Chua circuit is designed, its dimensionless fifth-order mathematical model is proposed. Due to the difference in the design of the characteristic equation of the two magnetron memristors, their positions form a symmetrical structure with respect to the capacitor. The existence of chaotic properties is proved by analyzing the stability of the system equilibrium point and Lyapunov exponents. The model of five-order heterogeneous memristive Chua system and two heterogeneous magnetron memristors are implemented by Multisim. Numerical calculation and experimental results show that heterogeneous magnetron memristive Chua …


Active Disturbance Rejection Sliding Mode Control For Time-Delay Systems, Suzhen Wang, Guofa Sun, Shengrong Liu Apr 2019

Active Disturbance Rejection Sliding Mode Control For Time-Delay Systems, Suzhen Wang, Guofa Sun, Shengrong Liu

Journal of System Simulation

Abstract: Aiming at the time-delay systems with uncertainty, this paper designs a third-order nonlinear feedback extended state observer (ESO) by using the coordinate transformation. The ESO can estimate both the system states and the total disturbance signal, and the nonlinear feedback has fast convergence. By the first-order approximation of the time-delay, the output feedback control problem of the time-delay system is transformed into controlling the second-order nonlinear uncertain system with unknown function. On the basis of the tracking differentiator (TD) and the designed ESO, the second-order sliding mode controller (SMC) is designed to realize the fast and accurate tracking …