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Articles 69271 - 69300 of 302422

Full-Text Articles in Physical Sciences and Mathematics

Forage Production Estimate Of Incienso (Flourensiathurifera (Mol.) Dc.), Repanda (Atriplex Repanda Phil.) And Numularia (Atriplex Nummularia Lindl.) According To Shrub Size And Annual Rainfall, P. Azócar, A. Mansilla, D. Troncoso, D. Patón Sep 2020

Forage Production Estimate Of Incienso (Flourensiathurifera (Mol.) Dc.), Repanda (Atriplex Repanda Phil.) And Numularia (Atriplex Nummularia Lindl.) According To Shrub Size And Annual Rainfall, P. Azócar, A. Mansilla, D. Troncoso, D. Patón

IGC Proceedings (1993-2023)

No abstract provided.


Case Studies In Developing Rangeland Sustainability Indicators: Scale Matters, B. H. Allen‐Diaz, Lynn Huntsinger, J. W. Bartolome, L. D. Ford Sep 2020

Case Studies In Developing Rangeland Sustainability Indicators: Scale Matters, B. H. Allen‐Diaz, Lynn Huntsinger, J. W. Bartolome, L. D. Ford

IGC Proceedings (1993-2023)

No abstract provided.


Development Of Ultrasonic-Based Ambient Desorption Ionization Mass Spectrometry, Linxia Song Sep 2020

Development Of Ultrasonic-Based Ambient Desorption Ionization Mass Spectrometry, Linxia Song

USF Tampa Graduate Theses and Dissertations

Ambient desorption/ionization techniques (ADI) have drawn significant attention in mass spectrometric instrumentation development. The analyte classes that are successfully studied by any ADI mass spectrometry (MS) method strongly depends on how gas-phase ions are generated. Spray-based techniques may ionize molecules across a wide range of mass-to-charge ratios, but are commonly used for polar analyte, however, suffers from severe matrix effect. Contrastingly, methods employing electric (or laser) plasmas are capable of ionization of polar and nonpolar analytes suffering from less matrix effect, but primarily targeting those with low molecular masses. Thus far, developments of universal ionization methods, which do not depend …


Use Of Advanced Statistical Techniques To Predict All-Cause Mortality In The Systolic Blood Pressure Intervention Trial, William Kostis, Javier Cabrera, Chun Pang Lin, John Kostis, Jennifer Wellings, Stavros Zinonos, Jeanne Dobrzynski, Daniel Blickstein Sep 2020

Use Of Advanced Statistical Techniques To Predict All-Cause Mortality In The Systolic Blood Pressure Intervention Trial, William Kostis, Javier Cabrera, Chun Pang Lin, John Kostis, Jennifer Wellings, Stavros Zinonos, Jeanne Dobrzynski, Daniel Blickstein

Department of Medicine Faculty Papers

Background: The Systolic Blood Pressure Intervention Trial (SPRINT) was conducted in patients with hypertension and additional risk for cardiovascular disease who were randomized to the intensive blood pressure group targeting systolic blood pressure (SBP) less than 120 mm Hg and to the standard group where the target was less than 140 mm Hg. Analyses were done in the matched group of participants with the same gender, same age (±2 years) and same SBP (±3 mm Hg) at three months of treatment regardless of initial randomization to intensive or standard group (shaded area in Figure 1). Methods and results: During 3.26 …


Weather Derivatives And The Market Price Of Risk, Julius Esunge, James J. Njong Sep 2020

Weather Derivatives And The Market Price Of Risk, Julius Esunge, James J. Njong

Journal of Stochastic Analysis

No abstract provided.


Trigger Points--Decision Tools To Mitigate Seasonal Climate Risk In Western New South Wales, Australia, Yohannes Alemseged, Ronald B. Hacker, W. J. Smith Sep 2020

Trigger Points--Decision Tools To Mitigate Seasonal Climate Risk In Western New South Wales, Australia, Yohannes Alemseged, Ronald B. Hacker, W. J. Smith

IGC Proceedings (1993-2023)

No abstract provided.


A Monitoring System To Aid Decision Making In Grassland Management In Arid Areas Of China, Zhongling Liu, Adrian Williams, Dunyuan Hao Sep 2020

A Monitoring System To Aid Decision Making In Grassland Management In Arid Areas Of China, Zhongling Liu, Adrian Williams, Dunyuan Hao

IGC Proceedings (1993-2023)

No abstract provided.


Assessing The Affect Of Distance From Settlements On Landscape Function Analysis Indices In Central Mongolia, J. Addison, M. Nyamtseren Sep 2020

Assessing The Affect Of Distance From Settlements On Landscape Function Analysis Indices In Central Mongolia, J. Addison, M. Nyamtseren

IGC Proceedings (1993-2023)

No abstract provided.


Beef Cattle Performance On Panicum Maximum Pastures Under Two Levels Of Fertilization In Brazil, Valéria P. B. Euclides, Manuel C. M. Macedo, Jean Amorim Costa, Wellington Fernandez Sep 2020

Beef Cattle Performance On Panicum Maximum Pastures Under Two Levels Of Fertilization In Brazil, Valéria P. B. Euclides, Manuel C. M. Macedo, Jean Amorim Costa, Wellington Fernandez

IGC Proceedings (1993-2023)

No abstract provided.


Short‐Term Response Of Preferred And Unpreferred Species To Sheep Grazing In A Patagonian Steppe, M. D. Valenta, R. A. Golluscio Sep 2020

Short‐Term Response Of Preferred And Unpreferred Species To Sheep Grazing In A Patagonian Steppe, M. D. Valenta, R. A. Golluscio

IGC Proceedings (1993-2023)

No abstract provided.


Vegetation Response To Grazing Management In A Mediterranean Grassland: A Long‐Term Synthesis, Marcelo Sternberg, Zalmen Henkin, Avi Perevolotsky, Eugene D. Ungar Sep 2020

Vegetation Response To Grazing Management In A Mediterranean Grassland: A Long‐Term Synthesis, Marcelo Sternberg, Zalmen Henkin, Avi Perevolotsky, Eugene D. Ungar

IGC Proceedings (1993-2023)

No abstract provided.


The Influence Of Tree Thinning On Grass Dry Matter Yield, With And Without Grazing By Herbivore Game Species In The Marakele Park, South Africa, G. N. Smit, F. C. Pienaar Sep 2020

The Influence Of Tree Thinning On Grass Dry Matter Yield, With And Without Grazing By Herbivore Game Species In The Marakele Park, South Africa, G. N. Smit, F. C. Pienaar

IGC Proceedings (1993-2023)

No abstract provided.


Grazing Disturbance A Benefit To Species Diversity In Re‐Established Native Grass Stands, Michael P. Schellenberg, Alan D. Iwaasa Sep 2020

Grazing Disturbance A Benefit To Species Diversity In Re‐Established Native Grass Stands, Michael P. Schellenberg, Alan D. Iwaasa

IGC Proceedings (1993-2023)

No abstract provided.


The Expansion From System Simulation To Domain Simulation, Xiaogang Qiu, Yazhou Chen, Zhang Peng Sep 2020

The Expansion From System Simulation To Domain Simulation, Xiaogang Qiu, Yazhou Chen, Zhang Peng

Journal of System Simulation

Abstract: With the generalization of simulation application and complex system simulation becoming the focus, domain simulation is becoming more and more important. In 1995 United States Department of Defense (DoD) presented the master plan of modeling and simulation, which gives birth to the basic idea of domain simulation. The advances in information technology such as network technology and cloud computing help domain simulation to access to use. Taking the change of simulation research object as the basis, the development of simulation research from the aspects of model researches, simulation tools and simulation applications are summarized. The goal of domain simulation …


Research On Geographical Battlefield Environment Model Facing Autonomous Platform, You Xiong, Jiangpeng Tian Sep 2020

Research On Geographical Battlefield Environment Model Facing Autonomous Platform, You Xiong, Jiangpeng Tian

Journal of System Simulation

Abstract: Battlefield environment model is an abstraction and description of the complex battlefield environment for specific needs. It supports the research and application of the nature and evolution of the battlefield environment. However, the existing battlefield environment model is mainly oriented to human war activities to describe the battlefield environment,and lacks the design for unmanned autonomous platforms. A multi-level battlefield environment model structure which couples the advantages of humans and machines is proposed, which can give full play to the machine's rapid numerical calculation capabilities at the geometric and feature levels, as well as human cognitive experience at the element, …


Combat Effectiveness Simulation Evaluation Framework Of Complex Weapon System, Yonglin Lei, Zhu Zhi, Bin Gan, Lei Sen, Chen Yong Sep 2020

Combat Effectiveness Simulation Evaluation Framework Of Complex Weapon System, Yonglin Lei, Zhu Zhi, Bin Gan, Lei Sen, Chen Yong

Journal of System Simulation

Abstract: Combat effectiveness evaluation of complex weapon system is a scientific issue both military departments and defense industry concern. Current researches on simulation-based weapon system combat effectiveness evaluation lack the specificity to complex weapon system and a simulation-based formal combat effectiveness evaluation framework is especially desired. A framework is created and formalized on three measure layers of performance-outcome-effectiveness. Within the framework, simulation inputs are classified into different categories different outcome measure layers and different effectiveness measure layers are considered. An example of combat effectiveness evaluation framework for typical ballistic missiles is presented to demonstrate the proposed framework.


Design And Simulation On Autonomous Landing Of A Quad Tilt Rotor, Supu Xiu, Yuanqiao Wen, Changshi Xiao, Haiwen Yuan, Wenqiang Zhan Sep 2020

Design And Simulation On Autonomous Landing Of A Quad Tilt Rotor, Supu Xiu, Yuanqiao Wen, Changshi Xiao, Haiwen Yuan, Wenqiang Zhan

Journal of System Simulation

Abstract: Aiming at the under-actuation of general quadrotors, a novel quad tilt rotor model is proposed. The model decouples the y-direction translation and roll rotation of a quadrotor by the four servos used respectively for the tilting control of the four propellers to realized the tilt hover and tilt flight of the UAV, the UAV can keep a tilt attitude which increases the maneuverability and the precise pose position and attitude control of the tilt UAV and ensures a good performance on the trajectory tracking and landing. A 5-degree polynomial optimization is used in UAV trajectory planning for the strong …


A Continuous Non-Invasive Blood Pressure Prediction Method Based On Improved Svr Learning, Haixia Fan, Xiaohui Chen Sep 2020

A Continuous Non-Invasive Blood Pressure Prediction Method Based On Improved Svr Learning, Haixia Fan, Xiaohui Chen

Journal of System Simulation

Abstract: Aiming at the accuracy of continuous non-invasmive monitoring of blood pressure by photoelectric method based on the photoplethysmography (PPG) signal and the electrocardiography (ECG) signal, is influenced by the differences of human characteristics, a blood pressure prediction method based on principal component analysis (PCA) and genetic algorithm (GA) to optimize machine learning model is proposed. The method processes the PPG signal, ECG signal and human body features to form a feature matrix, and uses an improved SVR learning model to perform regression training on the feature matrix and the real-time blood pressure value measured by the mercury sphygmomanometer. …


Numerical Research On Ballistic Limit Of Whipple Shield In High-Velocity Range, Yixiao Li, Shengjie Wang Sep 2020

Numerical Research On Ballistic Limit Of Whipple Shield In High-Velocity Range, Yixiao Li, Shengjie Wang

Journal of System Simulation

Abstract: Limited by the acceleration ability of two-stage light gas guns, few hypervelocity impact experiment of Whipple shield with projectile speed higher than 8 km/s has been performed. The ballistic limit equations can't fully describe the protection ability of Whipple shield in high-velocity range because of the lack of experimental data. GRAY three-phase equation of state is used in the material point method calculation program to simulate the penetration of thick target plate and the high-velocity impact of Whipple shield. The numerical result of Whipple shield ballistic limit shows that the ballistic limit in high-velocity range is higher than the …


Evaluation On Geo-Registration Accuracy Of Outdoor Augmented Reality, Deng Chen, You Xiong, Meixia Zhi Sep 2020

Evaluation On Geo-Registration Accuracy Of Outdoor Augmented Reality, Deng Chen, You Xiong, Meixia Zhi

Journal of System Simulation

Abstract: Geo-registration technology is a key technology for the combination of augmented reality and geographic information systems, and its registration accuracy has a significant impact on the availability of ARGIS. Aiming at this application, the basic concepts and principles of augmented reality geo-registration technology are analyzed, and the method for quantitative evaluation of geo-registration accuracy is proposed. Combined with the pre-acquired high-precision geographic information data, a variety of outdoor geo-registration experiments are carried out by using the different hardware devices, and the quantitative accuracy of different geo-registration methods is evaluated. The geo-registration errors and the problems existing in the practical …


Research On Recursive Variable Sampling Period Scheduling Algorithm Based On Two-Parameter Priority, Weiguo Shi, Xu Chao, Wang Xun, Xiangtai Wang Sep 2020

Research On Recursive Variable Sampling Period Scheduling Algorithm Based On Two-Parameter Priority, Weiguo Shi, Xu Chao, Wang Xun, Xiangtai Wang

Journal of System Simulation

Abstract: A recursive variable sampling periodic dynamic scheduling algorithm based on two-parameter priority is proposed for the resource-constrained network control system. The network demand degree and network urgency double parameter of the control loop are calculated, and the two-parameter weight is established by the two-square root mapping function which is created by the absolute value of the control loop error to realize the scheduling of the sensor priority. The comprehensive analysis of the control loop performance recursively adjusts the sampling period of each control loop, and completes the scheduling adjustment under the premise of ensuring the stability of the …


Interactive Assembly Simulation Platform For Complex Gearbox In Virtual Environmen, Chunyang Jia, Xiangjun Zou, Jinhui Li, Zeqin Zeng, Wang Jie Sep 2020

Interactive Assembly Simulation Platform For Complex Gearbox In Virtual Environmen, Chunyang Jia, Xiangjun Zou, Jinhui Li, Zeqin Zeng, Wang Jie

Journal of System Simulation

Abstract: Aiming at the human-computer interaction, behavior simulation and user design in virtual assembly, based on the complex gearbox of large tractors, the simulation method of dynamic motion and behavior of gear with multi-collision body is studied. The positioning method of multi-part model based on axis constraints and surface constraints in virtual environment is proposed. The virtual environment of human-computer interaction is developed. The consumed time of per frame is about 10 ms, and the complex variable-speed motion behavior and its simulation are realized. The virtual assembly system is equipped with AR interface, which can realize the active intelligent virtual …


Ship's Rudder/Fin Joint Anti-Rolling Mpc Control Based On Feedback Linearization, Li Hui, Yingnan Xie, Liqi Lan Sep 2020

Ship's Rudder/Fin Joint Anti-Rolling Mpc Control Based On Feedback Linearization, Li Hui, Yingnan Xie, Liqi Lan

Journal of System Simulation

Abstract: Aiming at the nonlinearity, strong coupling and multivariate characteristics of the ship motion system, and considering the influence of marine environment on ship motion, a four-degree-of-freedom (surging, swaying, rolling and yawing) motion nonlinear mathematical model is established to comprehensively represent the essential characteristics of ship motion. Since the model predictive control is an applied multivariable optimal control strategy, the ship rudder/fin joint anti-rolling Model Predictive Control (MPC) system based on feedback linearization is designed. The simulations of ship rolling and course-keeping joint control are carried out under different sea conditions, and the results show that the control method is …


Design Of Fragment Warhead Simulation System Based On Mvc Distributed Framework, He Miao, Wang Hao, Huang Yong, Xue Shao, Yinqing Shen Sep 2020

Design Of Fragment Warhead Simulation System Based On Mvc Distributed Framework, He Miao, Wang Hao, Huang Yong, Xue Shao, Yinqing Shen

Journal of System Simulation

Abstract: Numerical computation and visualization simulation are carried out for the whole physical process from the explosion of warhead to the fragments impacting target. The whole system is designed and implemented by using MVC architecture, Framework component library and JSON data format computer software technology, which make the system scalable, cross-platform and easy to maintain. The distributed computing architecture is designed according to the high computation, large data volume and multi-user concurrency in user scenarios. The simulation experiment results show that the distributed simulation of the system can satisfy the concurrent needs of multi-users, and the visual simulation effect …


Finite Element Method Evaluation On Chest Blunt Injury By Rubber Projectile, Wang Song, Renjun Zhan, Xiongyi Duan Sep 2020

Finite Element Method Evaluation On Chest Blunt Injury By Rubber Projectile, Wang Song, Renjun Zhan, Xiongyi Duan

Journal of System Simulation

Abstract: In order to reveal the non-lethal injury mechanism of rubber projectile and improve its safety service level, the 18.4 mm rubber projectile finite element model and the improved chest blunt injury assessment model are constructed and verified. The virtual impact test experiments under different loads are carried out, and the stress-time response and deformation-time response data are obtained. The results show that the time to reach the peak stress (less than 0.2 ms) is much shorter than the time to reach the maximum deformation variable (4~5 ms), which means the damage is not caused by the impact itself …


Eeg Classification Based On Multi-Domain Features And Random Subspace Ensemble, Deng Xin, Can Long, Jianxun Mi, Boxian Zhang, Kaiwei Sun, Wang Jin Sep 2020

Eeg Classification Based On Multi-Domain Features And Random Subspace Ensemble, Deng Xin, Can Long, Jianxun Mi, Boxian Zhang, Kaiwei Sun, Wang Jin

Journal of System Simulation

Abstract: Aiming at the preprocessing feature extraction and classification recognition in BCI system, a method for EEG classification of motion imagery based on random subspaces ensemble learning of multi-domain features is proposed. Based on the analysis on the ERD/ERS characteristics of motion imagery (MI) signals, the multi-domain features of best effective time and frequency bands are extracted as the feature vectors, and the scale of the random subspace ensemble with cross-validation is adaptively chosen, and the EEG classification is realized by using linear discriminant analysis (LDA) classifiers ensemble. The test results show that the accuracy of the multi-domain features and …


Dynamic Vehicle Distribution Path Optimization Based On Improved Intelligent Water Drop Algorithm, Shuangnan Fan, Jiming Chen, Weimin Gao, Zengfeng Wang Sep 2020

Dynamic Vehicle Distribution Path Optimization Based On Improved Intelligent Water Drop Algorithm, Shuangnan Fan, Jiming Chen, Weimin Gao, Zengfeng Wang

Journal of System Simulation

Abstract: In view of the unreasonable distribution path, low distribution efficiency and demand uncertainty in the current vehicle distribution process, a dynamic vehicle distribution path optimization method based on the improved intelligent drop algorithm is proposed. According to the customer's demand for delivery time, the soft time window penalty function and customer satisfaction function are constructed. Based on the characteristics of vehicle speed, damage cost, penalty cost and customer satisfaction of vehicle distribution, a vehicle path optimization model is established. The vehicle path optimization model is solved by the intelligent water droplet algorithm. The grey wolf optimization algorithm is used …


Optimal Control Research On Vehicle Magnetorheological Semi-Active Suspension Of Four Degrees Of Freedom, Yongshu Jia, Ahai Miu Sep 2020

Optimal Control Research On Vehicle Magnetorheological Semi-Active Suspension Of Four Degrees Of Freedom, Yongshu Jia, Ahai Miu

Journal of System Simulation

Abstract: Based on system dynamics theory of vehicle, aiming at the model of 1/2 vehicle suspension, the vehicle magnetorheological semi-active suspension dynamic equation and space state equation with four degrees of freedom are established. A linear two times optimal controller and control algorithm for semi-active suspension are designed, and the control strategy based on magnetorheological damper of subdivision vibration velocity is proposed. Suspension simulation model is established to analyze the optimal control effect in SIMULINK. The results show that the magnetorheological semi-active suspension system based on the optimal control of the vehicle can reduce vehicle vertical vibration acceleration and vehicle …


Dynamic Environmental And Economic Dispatching Of Wind Farm Based On Multi-Objective, Le Wei, Xijin Li Sep 2020

Dynamic Environmental And Economic Dispatching Of Wind Farm Based On Multi-Objective, Le Wei, Xijin Li

Journal of System Simulation

Abstract: Wind farms are developing rapidly under the new policy on energy resources vigorously advocated by the state. Its output scheduling is very complex, and needs the integration of economic and environmental factors. Aiming at the large prediction error of wind power, in the dynamic environmental economic dispatch of wind farm, the cost of rotating reserve is taken into account within the generation cost, and the demand of wind power prediction error for rotating reserve capacity is taken into account within the constraint condition. Aiming at the minimum total cost of power generation, the minimum total pollutant emission and minimum …


Operation Loss Reduction Control For Large-Scale Wind Farm Based On Hybrid Modeling Simulation, Yunqi Xiao, Wang Yi Sep 2020

Operation Loss Reduction Control For Large-Scale Wind Farm Based On Hybrid Modeling Simulation, Yunqi Xiao, Wang Yi

Journal of System Simulation

Abstract: Due to the large number of transformers and collection lines in large-scale wind farms, the losses of collecting system is serious in actual operation. A reactive power/voltage control strategy is proposed, which takes wind turbines as the distributed reactive power sources to optimize the power flow in wind farm and reduce the overall losses of collector system. To improve the efficiency of wind farm modeling and multi-scene loss reduction simulation, a hybrid modeling and simulation scheme based on combining object model configuration and control algorithm programming is proposed. The wind farm model consists of module configuration, and can be …