Numerical Analysis and Scientific Computing Commons^™

Extending Set Functors To Generalised Metric Spaces, Adriana Balan, Alexander Kurz, Jiří Velebil

Mathematics, Physics, and Computer Science Faculty Articles and Research

For a commutative quantale V, the category V-cat can be perceived as a category of generalised metric spaces and non-expanding maps. We show that any type constructor T (formalised as an endofunctor on sets) can be extended in a canonical way to a type constructor T_V on V-cat. The proof yields methods of explicitly calculating the extension in concrete examples, which cover well-known notions such as the Pompeiu-Hausdorff metric as well as new ones.

Conceptually, this allows us to to solve the same recursive domain equation X ≅ TX in different categories (such as sets and metric spaces) and …

An Evaluation Of Training Size Impact On Validation Accuracy For Optimized Convolutional Neural Networks, Jostein Barry-Straume, Adam Tschannen, Daniel W. Engels, Edward Fine

SMU Data Science Review

In this paper, we present an evaluation of training size impact on validation accuracy for an optimized Convolutional Neural Network (CNN). CNNs are currently the state-of-the-art architecture for object classification tasks. We used Amazon’s machine learning ecosystem to train and test 648 models to find the optimal hyperparameters with which to apply a CNN towards the Fashion-MNIST (Mixed National Institute of Standards and Technology) dataset. We were able to realize a validation accuracy of 90% by using only 40% of the original data. We found that hidden layers appear to have had zero impact on validation accuracy, whereas the neural …

Improving Vix Futures Forecasts Using Machine Learning Methods, James Hosker, Slobodan Djurdjevic, Hieu Nguyen, Robert Slater

SMU Data Science Review

The problem of forecasting market volatility is a difficult task for most fund managers. Volatility forecasts are used for risk management, alpha (risk) trading, and the reduction of trading friction. Improving the forecasts of future market volatility assists fund managers in adding or reducing risk in their portfolios as well as in increasing hedges to protect their portfolios in anticipation of a market sell-off event. Our analysis compares three existing financial models that forecast future market volatility using the Chicago Board Options Exchange Volatility Index (VIX) to six machine/deep learning supervised regression methods. This analysis determines which models provide best …

Application Of Virtual Reality In Rehabilitation Of Special Populations, Tingting Liu, Liu Zhen, Ping'an Qian, Rongrong Xuan, Wang Jin, Yanjie Chai

Journal of System Simulation

Abstract: With the continuous development of urbanization and the trend of population aging, the number of people who need physical and mental rehabilitation continues to increase. Using information technology to assist the rehabilitation process has the important practical significance. The existing studies about the application of virtual reality (VR) technology in the rehabilitation, psychological problems and children with autism for stroke are reviewed. A framework for the intelligent rehabilitation system is proposed. Virtual agent, the technology of somatosensory and voice recognition are advised to be used. Based on the proposed framework, a prototype rehabilitation game for autism and an upper …

A Review Of Rare Event Simulation, Liping Wang, Wenhui Fan

Journal of System Simulation

Abstract: Rare-event has a great significance for its lower probability of occurrence and greater harmfulness, the traditional Monte Carlo method is difficult to analyze it effectively. Rare-event simulation technique which is developed quickly and applied in many areas can sample the rare-event effectively with variance reduction methods and can estimate the occurrence probability of rare-event. The research status of rare-event simulation technique is summarized firstly; the principles, problems and progress of the main methods are analyzed and concluded secondly; after that the application fields of the technique are elaborated and summarized; the future development tendency of rare event simulation technique …

Integrated Modeling For Time Delay Stability Analysis In Gcps, Jianbo Jiang, Li Peng, Aimin Miao, Cao Min, Songhai Zhang, Tan Lei, Kerun Li

Journal of System Simulation

Abstract: According to the separation problems of physical and cyber modeling in time delay stability analysis for grid cyber-physical system (GCPS), an integrated modeling method is presented and proved by single machine infinite bus system (SMIBS). The time delay and stability of GCPS are analyzed and discussed, and the physical and cyber models of SMIBS are established respectively. The dynamic linking library by EA and VS based on information model (CIM) are generated, and the united simulation platform is achieved by MATLAB. The results of the simulation show that the unified structure of information flow …

Parameter Estimation Of Lfmcw Signals Based On Improved Sm Method, Jiang Li, Junni Zhou, Runling Yang, Liu Li

Journal of System Simulation

Abstract: The parameter estimation of linear frequency modulation continuous wave (LFMCW) signal is a research hotspot in electronic reconnaissance systems. In this paper, the time frequency distribution feature of LFMCW signals is studied first. Based on the improved S-method (SM), an algorithm for parameter estimation of LFMCW signals is proposed. It uses short-time Fourier transform (STFT) to calculate the SM with adaptive window width, which can suppress the crossterm interferences and improve the time-frequency resolution. Theoretical analysis and simulation experiment results demonstrate the validity of the proposed algorithm under low SNR.

Research On Method Of Battlefield Situation Representation Based On Multiplex Information Cell, Xiying Huang, Dinghai Zhao, Shao Wei

Journal of System Simulation

Abstract: We adopt the grid-space method to represent the battlefield as discrete cell model. And we construct the multiplex information cell (MIC) using the situation-meta’s information such as position, states collection, indexed by position. The positions of MICs correspond to the battlefield’s positions. Both of them can be represented as stack or data array. This method gives a way to build the whole mapping relationship between data structure which the computer can understand and the battle factors such as position and state of situation-meta. When the position or state of the situation-meta changes, the computer can redraw the view according …

Towards The Automatic Evolution Of Workload Models In Large-Scale Astronomical Data Management, Huajin Wang, Wan Meng, Han Rui, Ren Wei, Haiming Zhang, Jianhui Li

Journal of System Simulation

Abstract: The benchmark's guiding role in system selection/optimization requires its workload model has the ability to: Run on various systems of the target application scenario (be portable); Reflect the typical tasks' characteristics and data access patterns (be representative). The emerging systems and tasks in large-scale astronomical data management field have led workload models constructed by existing methods to be prone to lose portability and representativeness. An automatic evolutionary workload modeling method has been proposed: Abstract operations are used to keep the workload model’s portability; Automatic workload log analytics are used to keep the workload model’s representativeness. The feasibility of this …

Analysis Of Lane Changing Conflict Based On Tta In Expressway Weaving Area, Wang Bao, Linjie Gao, Zhicai Juan

Journal of System Simulation

Abstract: The study of lane changing behavior in expressway weaving area is of great significance to the analysis of the traffic flow conflict and driving behavior characteristics. In this paper, a lane changing conflict model was established and trajectory extraction software was used to extract and calculate TTA (time to avoidance) and TTC (time to collision). We got 336 TTAs and 233 TTCs and 4 grades of the lane changing conflict level were built by using statistical method. We came up with the proposed lane changing speed and some traffic management strategies. The study will help to …

Direct Parameter Identification Method For Steam Turbine And Its Governing System, Jingliang Zhong, Xiaolong Gou, Tongtian Deng

Journal of System Simulation

Abstract: Since most of the traditional parameter identification methods used in the steam turbine and its governing system have the shortages of poor fitness, complicated identification process and long period, a novel identification method based on least square theory, called direct identification method, is proposed in this paper. Parameter to be identified can be obtained quickly and accurately through direct identification method if the identification process is transferred to solve nonlinear equation which represents the minimal error between simulated data and measured data. The identification results show that during identification process the proposed method has high identification efficiency, accurate identification …

Research On Conceptual Model For Trainer Embedded Training System, Jierong Tian, Zhang Li, Han Liang, Cunhu Shi

Journal of System Simulation

Abstract: Embedded training is an effective way to solve the problem of pilot tactical training, and represents a new technique trend in military training. Aiming at the requirements of trainer embedded training, the visual conceptual model that includes case model, static model and dynamic model for trainer embedded training system is constructed by unified modeling language (UML). Based on the conceptual model and the trainer characteristics, with the consideration of the reality and the future development, the structure model of embedded training system is designed referring to foreign architecture of embedded training system. The bus communication of embedded training …

Damage Simulation Of A Certain Type Of Armored Equipment Based On Finite Element Analysis, Junqing Huang, Tuan Wang, Guanghui Li, Fan Rui

Journal of System Simulation

Abstract: Based on the finite element numerical simulation method, the damage simulation of a certain type of armored equipment was studied. The numerical simulation model of ammo power was established. Based on 3D modeling technology, the vulnerability model of the armored equipment in the component level with high-resolution was established. The spatial relation model of projectile and target was established based on the interaction analysis of projectile and target. According to the characteristic of ammo damage element, combined with the damage criterion of armored equipment component, the damage condition of the component and the damage grade of the armored equipment …

Analysis And Optimization For Combat Capability Based On Sequential Simulation Experiment, Chenyan Kong, Zhu Jing, Jiao Song, Shaojie Mao

Journal of System Simulation

Abstract: To deal with the optimization of combat capability, the sequential simulation experiment method was proposed. The simulation evaluation method with precision constraint was used to control the simulation running times. The sensitivity analysis experiment was carried out to identify the important factors affecting the combat capability. The relation model between the important factors and combat capability was constructed via regression analysis experiment. To get the combat capability improvement as large as possible with the price as small as possible, the optimization was used. In the application example, the air-defense combat capability was improved by the method.

Modeling And Simulation For Automobile Connecting Rod Production Line Based On System Dynamics, Li Han, Wenhui Fan, Feng Yuan, Mengni Zhu, Shengxiao Zhang

Journal of System Simulation

Abstract: In the production line system, it is of much significance to assign operation to workstations in order to balance the manufacturing workload and increase productivity under the given constraint conditions. Based on System Dynamics theory, this paper builds a simulation model of a connecting rod production line in an automobile component company. With this model, the paper analyses the balancing rate and influential factors. Then some preliminary optimization is made to improve the production line performance.

Modeling And Simulation Of Connecting Rod Production Line, Yuanyuan Yan, Wenhui Fan, Feng Yuan

Journal of System Simulation

Abstract: Discrete event system simulation method is widely applied to solve various problems, and line balancing problem is also one of them. In this paper, we use discrete event system simulation method to solve line balancing problem. Connecting rod production line is modeled by using DES. A production line model is built and simulated in AnyLogic, the bottleneck process and the problems to be optimized are analyzed. A small program in MATLAB is used to optimize the production line, and find the optimal solution. Simulate again.

Design Of Simulation Platform For Space Operation Mission, Yuan Jing, Jianpin Yuan, Mingming Wang, Wang Fei, Zhang Chi

Journal of System Simulation

Abstract: The design of simulation platform for space mission operations is investigated. The platform has the advantages of high generality and extensibility, being easy to build up new task. FMI (Functional Mockup Interface) standard is adopted to achieve integration of multisource models, and Python scripts are used to realize the task schedule. Unity3D is adopted to implement the visual display system which could display space manipulation process with high fidelity 3D virtual scenes. Configuration tool is developed to map the 3D objects in visual scene with simulation physical variables for complex space control mechanism, which greatly improves the …

Restrain Boundary Effect Of Emd Based On Least Square Fitting, Zhenpeng He, Zhiqi Zhu, Haichao Xie, Yawen Wang, Zongqiang Li, He Rui, Chaoping Du, Jinlan Li

Journal of System Simulation

Abstract: To improve the accuracy of mechanical fault diagnosis, it’s meaningful to do research on the boundary effect of EMD. In this article, least squares linear method is applied to extend local extremum points at the end of a data series, which judges that whether the maximum value is within the wave fluctuation range of the original signal maximum points, whether the minimum value is within the wave fluctuation range of the original signal minimum points. It compares the extended extreme points and endpoint values, so the best signal endpoint is obtained. By calculating the value of similarity coefficient and …

Simulation Research On Post-Earthquake Road Network Repair Schedule Under Dynamic Traffic Flows, Shuanglin Li, Bin Zheng

Journal of System Simulation

Abstract: It is critical to repair the road network immediately to improve the emergency efficiency after earthquake. A mathematics model for post-earthquake road network repair scheduling under dynamic traffic flows (PRNRSDTF) is created and a hybrid genetic algorithm is provided to maximum the cumulative utilities. Finally, in the context of Wenchuan earthquake, a numerical example is abstract from Jingyang district of Deyang City to verify the reliability and validity of the proposed model and algorithm. The normal road network repair scheduling model without considering dynamical traffic flows is taken as a comparison. The results show that the PRNRSDTF model …

Simulated Analysis Of Temporal Robustness For Composite Service, Hengzhou Ye, Taoshen Li, Yunhui Guan

Journal of System Simulation

Abstract: The execution time of a service may fluctuate due to the variety of network, CPU, disk I/O and workloads, which will affect the makespan of the composite service. It is crucial to study the probability distribution and influencing factors of the real makespan to guarantee the performance of the composite service. This paper adopts directed acyclic graph (DAG) to describe the composite service. Also, with the goal of evaluating the variety degree of the makespan, we propose a temporal robustness metric for composition services. Through the rigorous analysis, we can find the boundary of this metric. By the analysis …