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Articles 3901 - 3919 of 3919

Full-Text Articles in Systems Science

Simulation And Optimization On Electrodynamic Repulsion Force Of Contact System In Circuit Breaker With Oil Dashpot, Yanhua Qiao, Xiuping Su, Tianying Dong Jun 2018

Simulation And Optimization On Electrodynamic Repulsion Force Of Contact System In Circuit Breaker With Oil Dashpot, Yanhua Qiao, Xiuping Su, Tianying Dong

Journal of System Simulation

Abstract: A 3D finite element model for contact system of circuit breaker with oil dashpot is established. Two electrodynamic repulsion forces, the Holm force between contacts and the Lorentz force between the conductor arms, are analyzed. The current density distribution, magnetic intensity distribution and the forces of the contact and contact arm are obtained. Compared with the theoretical value, it shows that it is feasible to use this method to solve electrodynamic repulsion force. The main factors that influence the Holm force are analyzed. The simulation results show the changes of Holm force with different surface contact coefficient, contact pressure …

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Parallel Design And Load Balance Of Openmp Based Warfighting Simulation, Wang Xiao, Yaqi Liu, Yuben Tao Jun 2018

Parallel Design And Load Balance Of Openmp Based Warfighting Simulation, Wang Xiao, Yaqi Liu, Yuben Tao

Journal of System Simulation

Abstract: Parallel simulation is a main trend of large scale and high precision war fighting simulation (WS). However, currently there is no unified framework to design a parallel WS and no effective method to load balance of it. Based on the parallel agent theory, an OpenMP based parallel WS design framework (PWSF) is proposed. To solve the problem of the complex simulation load distribution resulted from the diversity of entities' models and the position independence of the interactions, a load balance method based on METIS multilevel graph partition tool is suggested. Based on the improved PHOLD test model, experiments on …

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3d Visual Effects Assessment Based On Comprehensive Weight, Yanyang Zeng, Zhenjing Feng Jun 2018

3d Visual Effects Assessment Based On Comprehensive Weight, Yanyang Zeng, Zhenjing Feng

Journal of System Simulation

Abstract: There are various indicators for assessing the 3D visual effects, while the general weight of each index needs pre-determined coefficients individually, for which either the expert knowledge model or theoretical model used has advantages and disadvantages empowerment. Based on expert knowledge and theoretical models, the comprehensive weight method, optimization model, and direct solution of the index weight vectors have subjective and objective information. Experimental results show that the method of determining the weight vector different sort results of the assessment is also slightly different. Integrated weighting method to determine the weight of each index and the corresponding results of …

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Algorithm For Tracking Position And Orientation Of Drug Delivery Capsules In Gastrointestinal Tract, Xudong Guo, Zhengping Lu, Qinfen Jiang, Shuyi Wang, Haipo Cui Jun 2018

Algorithm For Tracking Position And Orientation Of Drug Delivery Capsules In Gastrointestinal Tract, Xudong Guo, Zhengping Lu, Qinfen Jiang, Shuyi Wang, Haipo Cui

Journal of System Simulation

Abstract: To realize an accurate releasing by a drug-delivery capsule in the gastrointestinal tract, a method of magnetic vector detection with angle sensing has been presented to track the capsule in real time; and a prototype of the tracking system has been developed. Based on the fundamentals of spatial distribution of magnetic vector fields, a nonlinear model of tracking is established. An improved artificial bee colony algorithm is studied to solve the magnetic inverse problem. In the improved algorithm, a chaos operator is used to generate an initial population and a sort selection is used to prevent premature convergence. …

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Train Energy Saving Operation Based On Simulated Annealing Algorithm, Liu Wei, Jiaxuan Xu, Peipei Wang, Ruilong Liu, Jingkun Tang Jun 2018

Train Energy Saving Operation Based On Simulated Annealing Algorithm, Liu Wei, Jiaxuan Xu, Peipei Wang, Ruilong Liu, Jingkun Tang

Journal of System Simulation

Abstract: For the timing and energy saving algorithm of urban railway, the train operation iterative process was analyzed by dividing the operation intervals to meet the requirements of the subway trains timing energy saving operation. The differentiation was adopted to establish the train operation iterative model, and as a result the timing energy saving problem was transformed into the solution of train output using coefficient sequence. An optimization solving method based on simulated annealing algorithm was proposed and the algorithm was implemented using MFC program. Three intervals of Shanghai Metro Line 3 were selected and the solution of the train …

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Event-Triggered Non-Fragile H∞ State Estimation For Fuzzy Time-Delay Neural Networks, Yanqin Wang, Weijian Ren Jun 2018

Event-Triggered Non-Fragile H∞ State Estimation For Fuzzy Time-Delay Neural Networks, Yanqin Wang, Weijian Ren

Journal of System Simulation

Abstract: For a class of fuzzy neural networks with randomly occurring time-varying delays and randomly data packet loss, an event-triggered non-fragile H∞ state estimator is designed. The event-triggered condition is introduced to determine whether the signal is transmitted or not, so as to reduce the occupation rate of network resource. Random variables of Gaussian distribution and the multiplicative gain uncertainties are adopted to construct the non-fragile state estimator with randomly occurring gain variations. By constructing Lyapunov function, and via stochastic computation and linear matrix inequality technique, the sufficient conditions for the existence of non-fragile estimators are obtained, which guarantee …

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Svm Prediction Of Performance Degradation Of Rolling Bearings With Fusion Of Kpca And Information Granulation, Jiya Xu, Wang Yan, Dahu Yan, Zhicheng Ji Jun 2018

Svm Prediction Of Performance Degradation Of Rolling Bearings With Fusion Of Kpca And Information Granulation, Jiya Xu, Wang Yan, Dahu Yan, Zhicheng Ji

Journal of System Simulation

Abstract: To effectively predict the performance degradation index and its fluctuation ranges of the rolling bearing, a prediction method based on kernel principal component analysis algorithm and fuzzy information granulation using support vector machine is proposed. The kernel principal component analysis is utilized to preprocess the data to acquire the main feature vector, construct T2 and SPE statistics, and to analyze its trend. The statistical information is used as the performance degradation index. Theory of fuzzy information granulation is used to granulate the performance degradation index and extract the useful information. The granulated data are put to the support …

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Detail-Preserving Shape Deformation In Sph Fluid Control, Feng Gang, Shiguang Liu Jun 2018

Detail-Preserving Shape Deformation In Sph Fluid Control, Feng Gang, Shiguang Liu

Journal of System Simulation

Abstract: It remains a challenging problem to drive particles-based fluid simulation to match target shape and deform fluid shape between different models smoothly in fluid control, especially when the natural fluid motion should be preserved. To achieve the desired behavior, the models are divided into source objects and target objects, and the control particles are generated from them. According to a space point correspondence between source control particles and target control particles, the control particles' movements are calculated which drive fluid to match different models. The control energy from source control particles is transferred to target control particles so as …

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Test Data Compression Scheme For Fast Search Best Rational Approximate Fraction, Haifeng Wu, Wenfa Zhan, Yifei Cheng Jun 2018

Test Data Compression Scheme For Fast Search Best Rational Approximate Fraction, Haifeng Wu, Wenfa Zhan, Yifei Cheng

Journal of System Simulation

Abstract: Rapid growth of test data volume becomes a major factor for test time and manufacturing cost increasing. To reduce test data volume, a code-based compression scheme with fast search best rational approximate fraction is presented. The run-length data is converted into floating point numbers; and the equal best rational approximate fractions of floating point numbers is searched quickly; the appearing law of run-length data in the form of integer numerator and integer denominator is stored instead of storing run-length data directly. This scheme is compatible with traditional code-based methods. It also has simple compression and decompression protocol, good compression …

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Performance Analysis And Research Of Shark Fin Structure Based On Simulation, Liu Shuang, Lü Chao, Rao Yong, Shiming Wang Jun 2018

Performance Analysis And Research Of Shark Fin Structure Based On Simulation, Liu Shuang, Lü Chao, Rao Yong, Shiming Wang

Journal of System Simulation

Abstract: The shark fin, the pectoral fin and the dorsal fin were studied based on the numerical simulation method; the pressure field, velocity field and flow field of the specimen structure were analyzed with three different flow velocities; the analysis and comparison of the mechanical properties of caudal fin, dorsal fin and pectoral fin were presented. The results show that the setting width of the tail fin can be set to 0.5 ~ 4.8 meters so as to improve the anti-karman vortex effect; the width of the tail fins should be relatively narrow in order to guarantee the base of …

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Effect Of Interfacial Curvature On Drag Reduction Of Superhydrophobic Microchannels, Chunxi Li, Zhang Shuo, Xuemin Ye Jun 2018

Effect Of Interfacial Curvature On Drag Reduction Of Superhydrophobic Microchannels, Chunxi Li, Zhang Shuo, Xuemin Ye

Journal of System Simulation

Abstract: The two-dimensional fluid flow in superhydrophobic microchannels with transverse grooves was numerically simulated with Fluent to investigate the impact of the liquid-gas interface curvature on the effective slip behavior in the laminar regime. The effects of shear-free fraction, normalized periodic cell length and Reynolds number on the normalized slip length and pressure drop reduction are also examined. The results show that as protrusion angle increases, the normalized slip length and pressure drop reduction exhibit with single-hump variations. When θ=θopt, increments in the normalized slip length and pressure drop reduction tend to be greater as shear-free …

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Imu Single-Axis Rotation Method And Error Analysis Of Modulation Inertial Navigation System, Sun Wei, Ruibao Li, Zhang Yuan, Yang Dan Jun 2018

Imu Single-Axis Rotation Method And Error Analysis Of Modulation Inertial Navigation System, Sun Wei, Ruibao Li, Zhang Yuan, Yang Dan

Journal of System Simulation

Abstract: Aiming at the problem that inertial device bias has an influence on the improvement of system precision, a single axis error modulation scheme whose sensitive axis is misalignment with rotation axis which can continuously rotate in clockwise and counterclockwise is proposed. Based on the same level precision of inertial components in IMU, the IMU is installed on rotation mechanism with non-coincidence. The symmetric part of inertial device deviation can be compensated by the positive and negative cancellation of the device deviation in the rotation axis direction and the rotation modulation in the vertical plane of the rotary axis. The …

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Adaptation Of Legacy Computer Science Complexity Metrics To Sysml Diagrams, Victor Lopez Oct 2017

Adaptation Of Legacy Computer Science Complexity Metrics To Sysml Diagrams, Victor Lopez

Von Braun Symposium Student Posters

No abstract provided.

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Girl’S Cybersecurity Camp, Sarah Cunha, Dale Rowe Jan 2016

Girl’S Cybersecurity Camp, Sarah Cunha, Dale Rowe

Journal of Undergraduate Research

In 2015, the BYU Cybersecurity Research Lab (CSRL) held its first annual summer camp for Girls aged 14-18. A total of 38 girls attended the week’s activities and workshops. While over 75% of girls indicated they had taken a computing-related class, only 40% reported any significant interest in cybersecurity prior to the summercamp with 10% believing they had some experience in the field. At the conclusion of the camp, 80% of attendees reported a significant interest in the field with 100% of attendees interested in attending a similar event again.

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Simulation Modeling And Analysis Of Customs-Regulated Container Terminal Operations With Multimodal Transportation, Mariam A. Kotachi Apr 2014

Simulation Modeling And Analysis Of Customs-Regulated Container Terminal Operations With Multimodal Transportation, Mariam A. Kotachi

Engineering Management & Systems Engineering Theses & Dissertations

World trade has been increasing dramatically in the past two decades and, as a result, container exchange has grown significantly. Consequently and to meet this increase, several container terminals are expanding and many new ones are being established. A port with one or more container terminals is considered a complex system in which many entities interact to accomplish seamless handling of containers inbound and outbound. The level of complexity is drastically heightened for container terminals containing multimodal transportation systems as they typically involve ships, rail, and trucks arriving to one or more terminals delivering containers of different sizes to several …

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How To Improve Project Management For Agile Federation Development, Priyanka Kotikalpudi Apr 2010

How To Improve Project Management For Agile Federation Development, Priyanka Kotikalpudi

Engineering Management & Systems Engineering Theses & Dissertations

Developing a simulation federation out of a variety of heterogeneous simulation solutions is a complex task requiring very effective project management support in order to accomplish the common objectives and goals of this M&S federation. This thesis study conducts a detailed survey of available literature to identify the project management methods that can be extended to be applied to manage the development of simulation systems. The literature review led to the following two main results: (a) in general, there is insufficient literature dealing with M&S challenges for project management, (b) in particular, the two challenges of often changing requirements leading …

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Globally Convergent Approximate Dynamic Programming Applied To An Autolander, J.J. Murray, Richard Saeks, C.J. Cox, George G. Lendaris Jun 2001

Globally Convergent Approximate Dynamic Programming Applied To An Autolander, J.J. Murray, Richard Saeks, C.J. Cox, George G. Lendaris

Complex Systems Faculty Publications and Presentations

A globally convergent nonlinear Approximate Dynamic Programming algorithm is described, and an implementation of the algorithm in the linear case is developed. The resultant linear Approximate Dynamic Programming algorithm is illustrated via the design of an autolander for the NASA X-43 research aircraft, without a priori knowledge of the X-43's flight dynamics.

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Domain Limitations And Interface Requirements For Expert Developed Knowledge Based Systems, Bernard Lee Lewis Oct 1991

Domain Limitations And Interface Requirements For Expert Developed Knowledge Based Systems, Bernard Lee Lewis

Engineering Management & Systems Engineering Theses & Dissertations

The expanded use of graphical, case-based and object oriented techniques in expert systems creation has made it more practical for domain experts to develop their own applications. This thesis focuses on the elements necessary in an expert/developer interface and looks at various forms and techniques that exemplify such an approach. The spreadsheet metaphor is used for an interface or managed set of interfaces that a domain expert can use in building his own expert system or prototype. criteria are established for such interfaces and recent commercial offerings that make expert-created knowledge-bases more practical are reviewed for techniques that qualify. Approaches …

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Education Necessary For Air Force Software Managers To Use The Ada Programming Language And Software Engineering Effectively, James W. Worley Jr. Sep 1991

Education Necessary For Air Force Software Managers To Use The Ada Programming Language And Software Engineering Effectively, James W. Worley Jr.

Theses and Dissertations

This research investigated the perceived Ada and software engineering education needs of software managers throughout the Air Force and provided recommendations to Air Staff for developing the education. Since the Department of Defense mandated all DOD agencies use the Ada programming language for software development, the education of the personnel who have to support the policy has lagged behind the implementation Ada is not a simple language to use and is only fully effective if used with sound software engineering principles. A survey was given to Air Force mid-level personnel who manage software in some capacity. Of the software personnel …

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