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Articles 68641 - 68670 of 302451

Full-Text Articles in Physical Sciences and Mathematics

Research On Optimal Configuration Design Method Of Stewart Platform, Xuwei Fan, Lili Yang, Cheng Yu, Xiaoning Zhou, Yexin Zhang Oct 2020

Research On Optimal Configuration Design Method Of Stewart Platform, Xuwei Fan, Lili Yang, Cheng Yu, Xiaoning Zhou, Yexin Zhang

Journal of System Simulation

Abstract: Based on the structural singularity and configuration singularity of parallel mechanism, a safety mechanism design scheme of the Stewart platform is proposed to improve the workspace efficiency and engineering practicability. Taking the Stewart platform without any particularity as the research object, and considering the singular constraints of the structure, a dexterity index is proposed to achieve the optimization of the structural parameters. Analyzing and constructing the kinematics model of the Stewart platform, analyzing the singularities of the configuration bifurcations of 16 typical extreme poses, a secure workspace verification algorithm is proposed to make the whole workspace free of singularity. …


Optimization And Simulation Of Offshore Edge Computing Network For E-Pilotage, Bin Lin, Chenchen Song, Yajing Zhang, Jianli Duan Oct 2020

Optimization And Simulation Of Offshore Edge Computing Network For E-Pilotage, Bin Lin, Chenchen Song, Yajing Zhang, Jianli Duan

Journal of System Simulation

Abstract: In order to improve the safety of the ship's piloting process, an INA-based offshore edge computing network (IOECN) architecture is proposed to provide navigation assistance information. The Layout Optimization Problem (LOP) of network element nodes in the network is mainly studied. The mathematical model is used to convert the LOP into an Integer Linear Programming (ILP) problem. On condition of the required network coverage and connectivity, aiming to minimize the network cost, being solved by Gurobi and simulated and demonstrated by Matlab, the network optimization on different scales is obtained and the correctness and scalability of …


Visual Feedback Fuzzy Control For A Robot Manipulator Based On Svr Learning, Xianxia Zhang, Jinqiang Zhang, Zhiyuan Li, Shiwei Ma, Banghua Yang Oct 2020

Visual Feedback Fuzzy Control For A Robot Manipulator Based On Svr Learning, Xianxia Zhang, Jinqiang Zhang, Zhiyuan Li, Shiwei Ma, Banghua Yang

Journal of System Simulation

Abstract: A fuzzy controller based on SVR learning is proposed for uncalibrated robot visual servoing. In this paper, a fuzzy controller is used to directly construct the nonlinear mapping between image features and robot joint motion. The fuzzy basis function of the fuzzy controller is taken as the kernel function of an SVR and the equivalent relationship between the SVR and the fuzzy controller is established. The learned support vector from the SVR is used as the rule of the fuzzy controller. Since all rules are learned from the data, there is no need to manually design the rules. …


Research On Fuzzy Flexible Job Shop Scheduling Problem Based On Hybrid Qpso, Junxuan Li, Wang Yan, Zhicheng Ji Oct 2020

Research On Fuzzy Flexible Job Shop Scheduling Problem Based On Hybrid Qpso, Junxuan Li, Wang Yan, Zhicheng Ji

Journal of System Simulation

Abstract: To solve the flexible job shop scheduling problem of uncertain processing time, triangular fuzzy numbers are used to characterize the relevant time parameters and a Hybrid Quantum Particle Swarm Optimization (HQPSO) is proposed. On the basis of making full use of the global search capability of Quantum Particle Swarm Optimization, the search efficiency is increased by designing a boundary repair strategy and a cooperative update strategy. Meanwhile, the cross-operator and path relinking technique are used to in the operation sequence mapped by the excellent particles, which makes up the disadvantages of the insufficient ability of deeply exploration of …


Research On Adaptive Routing Algorithm For Wireless Weak-Connection Network, Hua Xiang, Hongjuan Yao, Wang Hai, Wang Zhao, Jietao Zhang, Lili Shu Oct 2020

Research On Adaptive Routing Algorithm For Wireless Weak-Connection Network, Hua Xiang, Hongjuan Yao, Wang Hai, Wang Zhao, Jietao Zhang, Lili Shu

Journal of System Simulation

Abstract: The wireless weak-connected network has the characteristics of long delay, high dynamic topology, and unstable links. With the lack of continuity from the source end to the destination end of network connection, in order to solve the problem of communication difficulty, the intelligence and adaptability of Physarum polycephalum are introduced, and the adaptive wireless weak-connected network routing algorithm is proposed. A wireless weak-connected network model is build and the mathematical relationships of link capacity is deduced. The next-hop selection strategy and optimal routing strategy is designed to achieve the best-effort delivery of data in wireless weak-connected network environmrnt. Simulation …


Adaptive Control Method Of High Proportion Distributed Generation Connected To Distribution Network, Weijie Dong, Keyan Liu, Yilong Wang, Xiaozhong Li, Yang Hao Oct 2020

Adaptive Control Method Of High Proportion Distributed Generation Connected To Distribution Network, Weijie Dong, Keyan Liu, Yilong Wang, Xiaozhong Li, Yang Hao

Journal of System Simulation

Abstract: Focus on the instability of the reactive power output precision caused by the voltage drop and loss of DG lines being switched to grid and the low output frequency and voltage caused by power deficiency of DG islanding, an improved droop control strategy is proposed to ensure the running stability of Active Distribution Network during DG connecting to network. The DG model applies the feedback regulation of f-U droop output power and voltage drop compensator. The control system is applied to the quasi-synchronization grid-connected model, island mode and the modes switching process of an active distribution network's domain transient …


Optimization Of Shore Bridge Driver Scheduling Strategy Considering Influence Of Illumination, Tiexin Wang, Haihong Yu, Danlan Xie, Yibin Wang Oct 2020

Optimization Of Shore Bridge Driver Scheduling Strategy Considering Influence Of Illumination, Tiexin Wang, Haihong Yu, Danlan Xie, Yibin Wang

Journal of System Simulation

Abstract: The luminous environment has an important effect on the efficiency of quay crane drivers' work. Aiming at the quay crane drivers' shift arrangement under the changing illumination intensity, the theoretical model of illumination influencing efficiency and the 3D simulation model of port operation are established. The influence of different lighting conditions on quay crane drivers' work is analyzed to find the optimal scheduling strategy. By comparing four different scheduling strategies, the optimal 6h interval scheduling is obtained, which increases the working efficiency by about 14% compared with the existing scheduling methods. It shows that when the total working …


Research On Simulation Optimization Of Intelligent Storage Robot Configuration Under Multiple Constraints, Guo Di, Danlan Xie, Ji Yuan Oct 2020

Research On Simulation Optimization Of Intelligent Storage Robot Configuration Under Multiple Constraints, Guo Di, Danlan Xie, Ji Yuan

Journal of System Simulation

Abstract: Aiming at the intelligent warehouse storage robot configuration, a discrete event simulation model based on queuing theory is constructed. Considering the influence of faults and the reliability and service intensity of the system, aiming at minimizing the total cost of distance cost, time cost, idle cost and purchase cost, a based on FlexSim simulation model is proposed. Discrete event simulation optimization method of the platform. By analyzing the system average team length, order average stay time and other indicators, the intuitionistic bottleneck of the system is combined with the actual operation data, and the configuration strategy of minimum system …


Research On Distribution Line Identification And Simulation Based On Sequence Impedance Method, Keyan Liu, Weijie Dong, Xueshun Ye, Muke Bai, Huaitian Zhang Oct 2020

Research On Distribution Line Identification And Simulation Based On Sequence Impedance Method, Keyan Liu, Weijie Dong, Xueshun Ye, Muke Bai, Huaitian Zhang

Journal of System Simulation

Abstract: The field fault test of distribution network cannot be repeated frequently, a line parameter identification and fault waveform reproduction method based on sequence impedance method is proposed to build the line sequence resistance model, and the π type equivalent lines are constructed. Based on the data of each node obtained in the field test process, the positive sequence impedance and zero sequence impedance parameters of π type equivalent circuits of all line sections are obtained by using the principle of symmetrical sequence components, and the digital model of the real lines in the field is established. The simulation results …


Research On Network Attack And Defense Situation Based On Game Theory Model And Netlogo Simulation, Xiaohu Liu, Hengwei Zhang, Yuchen Zhang, Ma Zhuang, Wenlei Lü Oct 2020

Research On Network Attack And Defense Situation Based On Game Theory Model And Netlogo Simulation, Xiaohu Liu, Hengwei Zhang, Yuchen Zhang, Ma Zhuang, Wenlei Lü

Journal of System Simulation

Abstract: Aiming at the problem that the existing modeling methods lack of the analysis on the behavior and trend of attack and defense game, the characteristics of network attack and defense game from the perspective of confrontation are analyzed Based on the static game theory of non- cooperative incomplete information, the network attack and defense game model is established, and the revenue quantification, game equilibrium calculation and decision-making of strategic confrontation result are given. The multi-agent simulation model of network attack and defense game is constructed. The simulation experiments under different strategy combinations and different initial numbers of players are …


Odu Helps Power Virginia’S Offshore Wind Project, Philip Walzer Oct 2020

Odu Helps Power Virginia’S Offshore Wind Project, Philip Walzer

News Items

No abstract provided.


Fluctuations And Correlations Of Transmission Eigenchannels In Diffusive Media, Nicholas Bender, Alexey Yamilov, Hasan Yllmaz, Hui Cao Oct 2020

Fluctuations And Correlations Of Transmission Eigenchannels In Diffusive Media, Nicholas Bender, Alexey Yamilov, Hasan Yllmaz, Hui Cao

Physics Faculty Research & Creative Works

Selective excitation of a diffusive system's transmission eigenchannels enables manipulation of its internal energy distribution. The fluctuations and correlations of the eigenchannel's spatial profiles, however, remain unexplored so far. Here we show that the depth profiles of high-transmission eigenchannels exhibit low realization-to-realization fluctuations. Furthermore, our experimental and numerical studies reveal the existence of interchannel correlations, which are significant for low-transmission eigenchannels. Because high-transmission eigenchannels are robust and independent from other eigenchannels, they can reliably deliver energy deep inside turbid media.


Comparative Study Of Silk-Based Magnetic Materials: Effect Of Magnetic Particle Types On The Protein Structure And Biomaterial Properties., Ye Xue, Samuel Lofland, Xiao Hu Oct 2020

Comparative Study Of Silk-Based Magnetic Materials: Effect Of Magnetic Particle Types On The Protein Structure And Biomaterial Properties., Ye Xue, Samuel Lofland, Xiao Hu

College of Science & Mathematics Departmental Research

This study investigates combining the good biocompatibility and flexibility of silk protein with three types of widely used magnetic nanoparticles to comparatively explore their structures, properties and potential applications in the sustainability and biomaterial fields. The secondary structure of silk protein was quantitatively studied by infrared spectroscopy. It was found that magnetite (Fe3O4) and barium hexaferrite (BaFe12O19) can prohibit β-sheet crystal due to strong coordination bonding between Fe3+ ions and carboxylate ions on silk fibroin chains where cobalt particles showed minimal effect. This was confirmed by thermal analysis, where a high temperature degradation peak was found above 640 °C in …


Simulation On Spatial-Temporal Dynamic Change Of Ocean Environment In Marine Simulators, Qianfeng Jing, Helong Shen, Zhengli Gao, Yin Yong Oct 2020

Simulation On Spatial-Temporal Dynamic Change Of Ocean Environment In Marine Simulators, Qianfeng Jing, Helong Shen, Zhengli Gao, Yin Yong

Journal of System Simulation

Abstract: Marine structures are subject to environmental interference all the time, and the simulation of the ocean environment significantly affects the realism of the marine simulators. The ocean environmental fields are generated by the numerical wave model, and the real ocean databases are developed based on SQLite. The actual wind, current, and wave information are obtained from the databases to keep consistency with the actual sea. The environmental disturbances are modeled and both the spatiotemporal-varying features and the coupling effects are brought into the simulation. The real voyage cases are reproduced by the proposed simulation method. The measured data …


Chaos Control Of Permanent Magnet Synchronous Motor Based On Finite Time Lasalle Invariant Set, Zhang Yun, Wang Cong, Hongli Zhang, Ma Ping Oct 2020

Chaos Control Of Permanent Magnet Synchronous Motor Based On Finite Time Lasalle Invariant Set, Zhang Yun, Wang Cong, Hongli Zhang, Ma Ping

Journal of System Simulation

Abstract: In order to effectively restrain the chaotic behavior of permanent magnet synchronous motor, an adaptive controller is designed based on finite time theory and LaSalle invariant set theorem. The chaotic dynamics characteristics of the permanent magnet synchronous motor system are analyzed, and the parameter fields of the system in different motion states are determined. It is proved theoretically that the controller can stabilize to the equilibrium point in finite time and can automatically track the equilibrium point of the system. Simulation results show that the control scheme is concise, faster and more stable. The research results are of great …


Prediction Of N-Acetylglucosamine Content Based On Rf-Ga-Bp Neural Network, Wenfeng Yang, Wang Yan, Zhichen Ji Oct 2020

Prediction Of N-Acetylglucosamine Content Based On Rf-Ga-Bp Neural Network, Wenfeng Yang, Wang Yan, Zhichen Ji

Journal of System Simulation

Abstract: In order to solve the problem that the content of N-acetylglucosamine (GlcNAc) in the process of preparing glucocosamine (GlcN) by microbial fermentation is difficult to measure online, an improved prediction algorithm based on stochastic forest algorithm, genetic algorithm and neural network algorithm is proposed. The algorithm utilizes the feature of decreasing average impurity in random forest algorithm to analyze the relevance of the input characteristics. The initial weights and thresholds of the neural networks are optimized by the genetic algorithm. A prediction model based on the RF-GA-BP algorithm is established based on the data from the fermentation process of …


A Photovoltaic Power Forecasting Method Based On Da-Rkelm Algorithm, Mingqi Wei, Tianrui Zhang, Xiuxiu Gao, Shumei Wang Oct 2020

A Photovoltaic Power Forecasting Method Based On Da-Rkelm Algorithm, Mingqi Wei, Tianrui Zhang, Xiuxiu Gao, Shumei Wang

Journal of System Simulation

Abstract: Aiming at the power grid safety problems caused by the fluctuation and randomness of photo-voltaic power generation, a method for predicting photo-voltaic power generation of a regular nuclear limit learning machine based on the optimization of a dragonfly algorithm was proposed. Through correlation analysis, the key factors affecting the photo-voltaic power generation are determined, and the photo-voltaic power prediction model is constructed. Dragonfly algorithm is used to obtain the optimal weight and threshold value of the network, and regularization function and kernel function are introduced based on the standard limit learning machine to avoid the over …


Search For Axionlike Particles Produced In E+E Collisions At Belle Ii, F. Abudin´En, I. Adachi, H. Aihara, N. Akopov, A. Aloisio, F. Ameli, N. Anh Ky, D. M. Asner, T. Aushev, V. Aushev, V. Babu, S. Baehr, S. Bahinipati, P. Bambade, Sw. Banerjee, S. Bansal, J. Baudot, J. Becker, P. K. Behera, Milind Purohit Oct 2020

Search For Axionlike Particles Produced In E+E− Collisions At Belle Ii, F. Abudin´En, I. Adachi, H. Aihara, N. Akopov, A. Aloisio, F. Ameli, N. Anh Ky, D. M. Asner, T. Aushev, V. Aushev, V. Babu, S. Baehr, S. Bahinipati, P. Bambade, Sw. Banerjee, S. Bansal, J. Baudot, J. Becker, P. K. Behera, Milind Purohit

Faculty Publications

We present a search for the direct production of a light pseudoscalar a decaying into two photons with the Belle II detector at the SuperKEKB collider. We search for the process e+eγa, aγγ in the mass range 0.2 < ma < 9.7 GeV/c2 using data corresponding to an integrated luminosity of (445± 3) pb−1. Light pseudoscalars interacting predominantly with standard model gauge bosons (so-called axionlike particles or ALPs) are frequently postulated in extensions of the standard model. We find no evidence for ALPs and set 95% confidence level upper limits on the coupling …


Age-Related Losses In Cardiac Autonomic Activity During A Daytime Nap, Pin-Chun Chen, Negin Sattari, Lauren N. Whitehurst, Sara C. Mednick Oct 2020

Age-Related Losses In Cardiac Autonomic Activity During A Daytime Nap, Pin-Chun Chen, Negin Sattari, Lauren N. Whitehurst, Sara C. Mednick

Psychology Faculty Publications

In healthy, young individuals, a reduction in cardiovascular output and a shift from sympathetic to parasympathetic (vagal) dominance is observed from wake into stages of nocturnal and daytime sleep. This cardiac autonomic profile, measured by heart rate variability (HRV), has been associated with significant benefits for cardiovascular health. Aging is associated with decreased nighttime sleep quality and lower parasympathetic activity during both sleep and resting. However, it is not known whether age-related dampening of HRV extends to daytime sleep, diminishing the cardiovascular benefits of naps in the elderly. Here, we investigated this question by comparing the autonomic activity profile between …


Newton Polygons Of Hecke Operators, Liubomir Chiriac, Andrei Jorza Oct 2020

Newton Polygons Of Hecke Operators, Liubomir Chiriac, Andrei Jorza

Mathematics and Statistics Faculty Publications and Presentations

In this computational paper we verify a truncated version of the Buzzard–Calegari conjecture on the Newton polygon of the Hecke operator T2 for all large enough weights. We first develop a formula for computing p-adic valuations of exponential sums, which we then implement to compute 2-adic valuations of traces of Hecke operators acting on spaces of cusp forms. Finally, we verify that if Newton polygon of the Buzzard–Calegari polynomial has a vertex at n≤15, then it agrees with the Newton polygon of T2 up to n.


Quantifying Controllability In Temporal Networks With Uncertainty, James C. Boerkoel Jr., Lindsay Popowski, Michael Gao, Hemeng Li, Savana Ammons, Shyan Akmal Oct 2020

Quantifying Controllability In Temporal Networks With Uncertainty, James C. Boerkoel Jr., Lindsay Popowski, Michael Gao, Hemeng Li, Savana Ammons, Shyan Akmal

All HMC Faculty Publications and Research

Controllability for Simple Temporal Networks with Uncertainty (STNUs) has thus far been limited to three levels: strong, dynamic, and weak. Because of this, there is currently no systematic way for an agent to assess just how far from being controllable an uncontrollable STNU is. We provide new insights inspired by a geometric interpretation of STNUs to introduce the degrees of strong and dynamic controllability - continuous metrics that measure how far a network is from being controllable. We utilize these metrics to approximate the probabilities that an STNU can be dispatched successfully offline and online respectively. We introduce new methods …


Hu Aquaponics Monitoring And Control System : European Annual Edunet Conference 2020, Rachel L. Fogle, Glenn P. Williams, Josh R. Krug Oct 2020

Hu Aquaponics Monitoring And Control System : European Annual Edunet Conference 2020, Rachel L. Fogle, Glenn P. Williams, Josh R. Krug

Presidential Research Grants

The functional purpose of the HU Aquaponics Monitoring and Control System Project is to develop an environmental and plant monitoring and control system for the HU Aquaponics Lab, located in the Student Union. The project involves the design and implementation of technology that will regularly take measurements from the environment (e.g., air temperature, water temperature, pH, dissolved oxygen, etc). PLCnext Technology will systematically collect, store, and web-publish the measurement data for HU researchers and the public to use for scientific research.


Transesterification Of Poly(Ethyl Glyoxylate): A Route To Structurally Diverse Polyglyoxylates, Rebecca E. Yardley, Amir Rabiee Kenaree, Xiaoli Liang, Elizabeth R. Gillies Oct 2020

Transesterification Of Poly(Ethyl Glyoxylate): A Route To Structurally Diverse Polyglyoxylates, Rebecca E. Yardley, Amir Rabiee Kenaree, Xiaoli Liang, Elizabeth R. Gillies

Chemistry Publications

Polyglyoxylates are a class of self-immolative polymers that depolymerize in solution and the solid state. The glyoxylic acid degradation product is a metabolite in the glyoxylate cycle and can also be processed in the liver in humans, making polyglyoxylates attractive for applications in the environment and in medicine. Although expanding the scope of available polyglyoxylates would enable new properties and applications, highly pure glyoxylate monomers are required for polymerization, and this level of purity is difficult to achieve for many potential monomers. To address this challenge, we report here the 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD)-catalyzed post-polymerization transesterification of poly(ethyl glyoxylate) (PEtG) as a …


Dupin Submanifolds In Lie Sphere Geometry (Updated Version), Thomas E. Cecil, Shiing-Shen Chern Oct 2020

Dupin Submanifolds In Lie Sphere Geometry (Updated Version), Thomas E. Cecil, Shiing-Shen Chern

Mathematics and Computer Science Department Faculty Scholarship

A hypersurface Mn-1 in Euclidean space En is proper Dupin if the number of distinct principal curvatures is constant on Mn-1, and each principal curvature function is constant along each leaf of its principal foliation. This paper was originally published in 1989 (see Comments below), and it develops a method for the local study of proper Dupin hypersurfaces in the context of Lie sphere geometry using moving frames. This method has been effective in obtaining several classification theorems of proper Dupin hypersurfaces since that time. This updated version of the paper contains the original exposition together …


Rethinking The Weakness Of Stream Ciphers And Its Application To Encrypted Malware Detection, William Stone, Daeyoung Kim, Victor Youdom Kemmoe, Mingon Kang, Junggab Son Oct 2020

Rethinking The Weakness Of Stream Ciphers And Its Application To Encrypted Malware Detection, William Stone, Daeyoung Kim, Victor Youdom Kemmoe, Mingon Kang, Junggab Son

School of Computing Faculty Scholarship and Creative Works

One critical vulnerability of stream ciphers is the reuse of an encryption key. Since most stream ciphers consist of only a key scheduling algorithm and an Exclusive OR (XOR) operation, an adversary may break the cipher by XORing two captured ciphertexts generated under the same key. Various cryptanalysis techniques based on this property have been introduced in order to recover plaintexts or encryption keys; in contrast, this research reinterprets the vulnerability as a method of detecting stream ciphers from the ciphertexts it generates. Patterns found in the values (characters) expressed across the bytes of a ciphertext make the ciphertext distinguishable …


Study On Benefit Detection Of The Grassland Desertification Control Project In Xianghuang Banner, Inner Mongolia Based On "3s" Technology, Qiuju Wang, Xinhong Wu, Tingting Yang Oct 2020

Study On Benefit Detection Of The Grassland Desertification Control Project In Xianghuang Banner, Inner Mongolia Based On "3s" Technology, Qiuju Wang, Xinhong Wu, Tingting Yang

IGC Proceedings (1993-2023)

No abstract provided.


The Development Of Landsat Cover Change Analysis In The Pastoral Grasslands Of Western Australia, Philip Thomas, Jeremy Wallace Oct 2020

The Development Of Landsat Cover Change Analysis In The Pastoral Grasslands Of Western Australia, Philip Thomas, Jeremy Wallace

IGC Proceedings (1993-2023)

No abstract provided.


Application Of Geographic Information System (Gis) For Developing Range Improvement And Reclamation Plans In Taleghan Summer Pastures, M. Tahmoures, Mohammad Jafary, A. Farsoodan Oct 2020

Application Of Geographic Information System (Gis) For Developing Range Improvement And Reclamation Plans In Taleghan Summer Pastures, M. Tahmoures, Mohammad Jafary, A. Farsoodan

IGC Proceedings (1993-2023)

No abstract provided.


Classification Of Rangeland Resource Types Based On Multi‐Source Remote Sensing Data, Xiaoqing Sui, Shazhou An, Kun Wang Oct 2020

Classification Of Rangeland Resource Types Based On Multi‐Source Remote Sensing Data, Xiaoqing Sui, Shazhou An, Kun Wang

IGC Proceedings (1993-2023)

No abstract provided.


Monitoring Rangeland Community/Health Change Using Multispectral And Hyperspectral Satellite Data, Nadia Rochdi, Peter Eddy, Jinkai Zhang, Karl Staenz Oct 2020

Monitoring Rangeland Community/Health Change Using Multispectral And Hyperspectral Satellite Data, Nadia Rochdi, Peter Eddy, Jinkai Zhang, Karl Staenz

IGC Proceedings (1993-2023)

No abstract provided.