Physical Sciences and Mathematics Commons^™

Study On Bidirectional Coupling Of Human Thermal Comfort Parameters And Cabin Thermal Environment, Jue Qu, Dayan Wang, Wang Wei, Sina Dang

Journal of System Simulation

Abstract: At present, for the existing cockpit heat system, are studied more the airflow tissue parameters of the thermal environment and the human heat regulation is taken into account less, which leads to the low accuracy of simulation result evaluating the human thermal comfort. Through CFD (computational fluid dynamics) method, energy equation, RANS (reynolds-average navier-stokes) equation, and N-S(navier-stokes) equation, by combining the human temperature distribution with the cabin thermal environment parameters, the cabin heat system model based on the human heat regulation is established. The model considers the interacting influence of the human thermal regulation and the thermal environmental airflow …

Time-Varying Output Formation Tracking Control Of Discrete-Time Heterogeneous Multi-Agent Systems, Xiaolong Qi, Xuguang Yang

Journal of System Simulation

Abstract: Aiming at the discrete-time heterogeneous multi-agent systems with different dimensions and parameters, the time-varying output formation tracking control is studied by using the output regulation method. Assuming that the multi-agents system is consisted of multiple followers and multiple leaders, and the followers can't obtain the leaders' states, the distributed observers are designed by using the neighboring relative information. Based on the states of the distributed observers, the time-varying output formation tracking protocols and algorithm are presented by using the states feedback, and the sufficient conditions that guarantee the protocols' effectiveness are also given. The simulation results show that, …

Wsn Clustering Routing Protocol For Bridge Structure Health Monitoring, Li Gang, Caixia Zhang, Shaolin Hu, Xiangdong Wang, Guo Jing

Journal of System Simulation

Abstract: In the specific application of bridge structure health monitoring (BSHM), clustering based only on the geographic location of nodes or using a single-hop strategy to complete inter-cluster routing may cause the unstability of the entire wireless sensor networks(WSN). For WSN in BSHM scenario, the concept of "energy distribution" is proposed, and an energy balance clustering routing protocol energy balance protocol(EBP) is designed. The second clustering, the high-energy areas in WSN bear more energy consumption, and a multi hop strategy based on region division is designed to control the number of forwarding hops. The simulation results show that, compared with …

Optimization Of Household Electricity Consumption Period Based On Improved Multi-Objective Particle Swarm Optimization, Xiuying Yan, Miaomiao Dang

Journal of System Simulation

Abstract: Aiming at the household power load scheduling optimization, three objectives of the cost of electricity, satisfaction and user-side fluctuation degree are taken into comprehensive account. An improved adaptive weight multi-objective particle swarm optimization (IAW-MOPSO) algorithm is proposed to realize the scheduling optimization of household power load. The local improvement ability and global search ability of particle swarm optimization are balanced by updating the inertia weight of particle fitness value. The simulation results of five groups show that the proposed optimization strategy reduces the electricity charge by 29%, ensures the stability of electricity consumption in the peak period, and …

Adaptive Optimization In Feature-Based Slam Visual Odometry, Yanan Yu, Dunhuang Shi, Chunjie Hua

Journal of System Simulation

Abstract: Aiming to reduce the impact of dynamic environments on simultaneous localization and mapping (SLAM) of mobile robots, an adaptive optimization method in a feature-based visual odometry is proposed. The method helps to improve the invariance of image feature in illumination changing situation and to extract features effectively in areas where the texture information is not sufficient to make contributions to feature matching. Meanwhile, down sampling is applied to establish image pyramids and each scaled image is divided into cells based on a defined rule. Illumination adaptive nonlinear adjustments for each cell are applied to increase the image details, and …

Planning And Analysis On Uav Trajectory Based On Pce Method, Sijie Zeng, Yan Liang, Xiaojun Duan

Journal of System Simulation

Abstract: Focusing on the uncertainty in the UAV trajectory planning, combined with the artificial potential energy method, a UAV trajectory planning method based on polynomial chaos expansion (PCE), which can also efficiently obtain the optimal parameters of the model based on artificial potential field method is proposed. The PCE proxy model is established, and the stochastic collocation method is used to quickly solve the problem, so as to avoid the insufficient computing resources. Through the Sobol sensitivity analysis, the calculation overhead of the uncertainty parameters in the trajectory planning model is reduced. Cases of UAV trajectory planning prove the effectiveness …

Research On Intelligent Vehicle Trajectory Tracking Control Based On Robust Model Prediction, Hongguang Lu, Shuen Zhao

Journal of System Simulation

Abstract: Aiming at the low control accuracy and poor robustness of traditional trajectory tracking controller based on the tracking error model in complex driving environment, a robust model predictive trajectory tracking control strategy is designed. The vehicle convex multicellular dynamic model is used to explicitly describe the vehicle dynamic characteristics, and the robust performance objective function is designed in combination with the trajectory tracking multi-objective constraint, and the state feedback control law is solved through the linear matrix inequality optimization. Feedforward control is introduced to eliminate the steady-state errors and improve the tracking accuracy. The simulation result shows that …

Agent- Based Research On Power Absorption Simulation Analysis Of Renewable Energy, Zhang Luan, Zhengjun Luo, Dequn Zhou

Journal of System Simulation

Abstract: Aiming at the “three abandonment”, a guarantee mechanism for the consumption of renewable energy power is proposed in our country. In order to stimulate the consumption of renewable energy power, a multi-agent simulation method is used to analyze the transaction behavior and interaction of market players, and the key factors affecting the consumption of renewable energy power is analyzed to simulated the consumption of renewable energy and the evolution of the number of active consumers. The results show that the subscribed green certificate can directly promote the consumption of renewable energy power, and it is necessary to comprehensively consider …

Autonomous Vehicle Path Tracking Control System Based On Energy Optimization, Xiaolong Wu, Fugen Xia, Chen Jing, Xu Jia

Journal of System Simulation

Abstract: Powertrain control is important to the dynamic performance and economy of driverless cars and a path following control strategy based on energy optimization is proposed. The control strategy includes two parts. The nonlinear model predictive control is used in the upper controller to calculate the required power parameters and front wheel angle. The lower-level controller is designed based on the optimal value of motor energy consumption which ensure the motor being always running at the optimal state of efficiency. In addition, the continuously variable transmission (CVT) is dynamically adjusted according to the motor state to meet the vehicle power …

The Distance And Dynamical History Of The Virgo Cluster Ultradiffuse Galaxy Vcc 615, J. Christopher Mihos, Patrick R. Durrell, Elisa Toloba, Patrick Côté, Laura Ferrarese, Puragra Guhathakurta, Sungsoon Lim, Eric W. Peng, Laura V. Sales

Pacific Faculty Work

We use deep Hubble Space Telescope imaging to derive a distance to the Virgo Cluster ultradiffuse galaxy (UDG) VCC 615 using the tip of the red giant branch (TRGB) distance estimator. We detect 5023 stars within the galaxy, down to a 50% completeness limit of F814W ≈ 28.0, using counts in the surrounding field to correct for contamination due to background sources and Virgo intracluster stars. We derive an extinction-corrected F814W tip magnitude of , yielding a distance of Mpc. This places VCC 615 on the far side of the Virgo Cluster (d Virgo = 16.5 Mpc), at a Virgocentric …

Machine Learning Approach To Simulate Soil Co2 Fluxes Under Cropping Systems, Toby A. Adjuik, Sarah C. Davis

Biosystems and Agricultural Engineering Graduate Research

With the growing number of datasets to describe greenhouse gas (GHG) emissions, there is an opportunity to develop novel predictive models that require neither the expense nor time required to make direct field measurements. This study evaluates the potential for machine learning (ML) approaches to predict soil GHG emissions without the biogeochemical expertise that is required to use many current models for simulating soil GHGs. There are ample data from field measurements now publicly available to test new modeling approaches. The objective of this paper was to develop and evaluate machine learning (ML) models using field data (soil temperature, soil …

Fault Tolerant Control And Simulation Of Quadrotor Based On Adaptive Observer, Zhao Jing, Wang Peng, Xiaoqian Ding, Guoping Jiang, Fengyu Xu, Yanfei Sun

Journal of System Simulation

Abstract: Focusing on the actuator fault of quadrotor, an integral backstepping sliding mode combined with adaptive observer is proposed to ensure the safety and reliability of the quadrotor. A dynamic model of the quadrotor with actuator fault are established. An adaptive observer is proposed to observe the state and estimate the actual value of the fault. The attitude fault tolerant controller and position controllers are designed by the method of integral backstepping combined with the sliding mode control to complete the trajectory tracking of attitude and position. The simulation results show that the control strategy can quickly and accurately track …

Simulation Of Rocket Exhaust Plumes Recognition Based On Dynamic Time Warping, Liu Hao, Hongxia Mao, Zhihe Xiao, Liu Zheng

Journal of System Simulation

Abstract: By analyzing the infrared radiation characteristics of the rocket exhaust plumes and summarizing the changing law of the radiant intensity sequence, an improved recognition algorithm based on Dynamic Time Warping algorithm is proposed. In order to improve the effect of sequence shape similarity measurement, the distance matrix and matching path are calculated by the derivative sequence, and the distance is recalculated according to the matching path and radiant intensity value. The problem of path matching affected by the non-uniformity of observation sequence length is solved to a certain extent by using the prefix and suffix relaxation factors. The simulation …

Approval Letter For The Revised Draft Final Butte Priority Soils Operable Unit (Bpsou) Revised Butte Reclamation Evaluation System (Bres) Field Manual (Dated July 2021), Nikia Greene

Silver Bow Creek/Butte Area Superfund Site

No abstract provided.

Digital Evidence In Appeals Of Criminal Cases Before The U.S. Courts Of Appeal: A Review Of Decisions And Examination Of The Legal Landscape From 2016 – 2020, Martin Novak

Journal of Digital Forensics, Security and Law

This study is a follow-up to Digital Evidence in Criminal Cases before the U.S. Courts of Appeal: Trends and Issues for Consideration – 2010 to 2015. The current study examines appeals of criminal cases before the United States Courts of Appeal from January 2016 through August 2020, where one or more appeal claims were related to digital evidence. The purpose of this research was to determine if the legal landscape has changed since 2015; examine the most relevant legal issues related to digital evidence; and analyze how precedential cases may have affected digital forensics as evidence.

Engine Wear Fault Diagnosis Based On Supervised Kernel Entropy Component Analysis, Zhichao Zhu, Dinghui Wu, Yuanchang Yue

Journal of System Simulation

Abstract: Focus on the influence of environment on engine operation, which leads to a large amount of redundant information and nonlinear structure in oil spectral data that affects the engine fault diagnosis results, the feature extraction method of SKECA (supervised kernel entropy component analysis) is proposed. A supervised learning algorithm is adopted on the basis of Kernel Entropy Component Analysis, which extracts the inherent geometric features of oil spectrum data to make the extracted fault features include the discriminative information. GA (genetic algorithm) is used to find parameters to optimize the results of feature extraction, and SVM (support vector machine) …

Visual Analysis Of Cross-Domain Association Of Time-Series Data, Beibei Han, Yingmei Wei, Yujie Fang, Shanshan Wan

Journal of System Simulation

Abstract: Time series data is the important research object of data mining. The current visual analysis technology of time series data rarely conducts the cross-domain correlation. The development and evolution of statistical time series data in the spatio-temporal domain and the text theme data in the cognitive domain cannot be simulitaneously supervised in a unified view. The user's visual analysis process based on cross-domain time series data is abstracted and a visual analysis process model is proposed. A multi-view collaborative cross-domain correlation visual analysis tool is designed on the basis of the model. The case study of epidemic time …

Uncertainty Simulation Method Based On Deep Bayesian Networks Learning, Nie Kai, Kejun Zeng, Qinghai Meng

Journal of System Simulation

Abstract: There are lots of uncertain elements in battlefields situation assessment and the uncertainty simulation would enhance the ability of situation assessment. A deep variational autoencoder bayesian networks (BN) model with memory module is proposed aiming at the problem of being unable to represent the uncertainties exactly caused by the various combat objects and more uncertain elements. Based on the deep BN learning, the situation assessment model is designed from the deep generative model. The principle of deep generative model mixing with the memory module is discussed and the leaning and reasoning process of the model is explained. The proposed …

Optimization And Prediction For Multi-Robot Combination Maximum Coverage Area, Yutong Wang, Shiwei Ma, Yuanrui Yang, Chaoyu Chen

Journal of System Simulation

Abstract: Aiming at the optimal control of the multi-robot combination maximum coverage area, based on the intensity radial attenuation disc model and following the superposition principle, a method for estimating, optimizing and predicting the effective coverage area of the multi-robot combination is proposed. The Monte Carlo method is used to estimate the effective coverage area of the robot combination, and the multiple population genetic algorithm is used to obtain the maximum effective coverage area of the combination, and the support vector machine regression is used to predict the relationship between the number of robots and the maximum effective coverage area. …

Research And Implementation Of On-Board Human Factors Collaborative Simulation System, Changqing Yin, Tianran Tan, Jianmin Wang

Journal of System Simulation

Abstract: In order to improve the multi-vehicle evaluation and follow the trend of the Internet of Vehicles in modern vehicle-road collaborative system, an on-board human factors collaborative simulation system is built. Distributed theory is used to establish a joint platform for vehicle simulation, and an on-board human factors co-simulation system is built and MQTT network is used to optimize the data distribution mechanism and data collection mechanism. The simulation experiment shows that the built on-board human factor co-simulation platform reduces the coupling between the participating experimental subsystems and the main system, and has good robustness and flexibility. The distributed data …

Design And Implementation Of Photovoltaic Energy Harvesting Automaton, Iskandar Askarov

Theses

Global domestic electricity consumption has been rapidly increasing in the past three decades. In fact, from 1990 to 2020, consumption has more than doubled from 10,120 TWh to 23,177 TWh [1]. Moreover, consumers have been turning more towards clean, renewable energy sources such as Photovoltaic. According to International Energy Agency, global Solar power generation alone in 2019 has reached almost 3% [4] of the electricity supply. Even though the efficiency of photovoltaic panels has been growing, presently, the highest efficiency solar panels available to an average consumer range only from 20%-22% [14]. Many research papers have been published to increase …

Research On Optimal Allocation Method Of Aircraft Towing Rules Based On Multi-Agent, Zhao Zheng, Hu Li, Yuanyuan Qian, Jin Hui, Aiping Jia

Journal of System Simulation

Abstract: In order to study and optimize the effect of aircraft towing rules on aircraft on bridge rate and flight normality, a towing rule configuration method based on surface capacity and demand balance is proposed. By constructing a multi-agent discrete simulation model based on surface operation, the collaborative optimization effect of aircraft on bridge rate and flight regularity is achieved, and which is verified by the example of Beijing Daxing International Airport. The results show that the towing rule configuration method based on airfield capacity and demand balance can obviously improve the aircraft on bridge rate and flight normality, …

Coupling Between Alfvén Wave And Kelvin–Helmholtz Waves In The Low Latitude Boundary Layer, Eun-Hwa Kim, Jay R. Johnson

Faculty Publications

The Kelvin–Helmholtz (KH) instability of magnetohydrodynamic surface waves at the low latitude boundary layer is examined using both an eigenfrequency analysis and a time-dependent wave simulation. The analysis includes the effects of sheared flow and Alfvén velocity gradient. When the magnetosheath flows are perpendicular to the ambient magnetic field direction, unstable KH waves that propagate obliquely to the sheared flow direction occur at the sheared flow surface when the Alfvén Mach number is higher than an instability threshold. Including a shear transition layer between the magnetosphere and magnetosheath leads to secondary KH waves (driven by the sheared flow) that are …

Impact Of Enclosures On Range Productivity In Chepareria West Pokot County Kenya, Regina W. Waiganjo, P. N. Mwangi, Rebecca H. Karanja

IGC Proceedings (1977-2023)

In the semi-arid areas of West Pokot particularly Chepareria, majority of the people live semi sedentary lives while others are nomadic pastoralists. In the last three decades, there have been concerted efforts to restore and improve rangeland in this area. Use of enclosures, which is one of the key interventions, by the Vi Agro- forestry a Non-Governmental Organisation, enhancing with many ecological processes such as disturbance, is a method of rehabilitating degraded rangeland, which in turn affects vegetation dynamics. Adoption of these strategies by farmers has been gradual and some areas are still open and degraded. The aim of this …

Increased Above-Ground Biomass And Plant Species Decline Related To The Presence Of Eragrostis Curvula Across Multiple Grazing Grasslands In The Snowy Monaro Region Of Australia, J. Brown, L. Ingram

IGC Proceedings (1977-2023)

"It will be noticed that invasions most often come to cultivated land, or to land much modified by human practice." This quote was published in 1958 by Charles Elton, and holds true today, backed by empirical evidence suggesting mechanisms of disturbance, plant functional traits and propagule pressure can push a cultivated system towards an invaded state. 17 farms, with either a current or previous history of grazing and land modification, within the Snowy Monaro Region, NSW, Australia, were surveyed to explore the relationship between the non-native C4 perennial tussock grass Eragrostis curvula [Schrad.] Nees. and species richness. As E. curvula …

The Use Of Open Communal Grazing Designs To Screen Options For Grazing Management, David R. Kemp, D. L. Michalk, P. M. Dowling, G. Millar

IGC Proceedings (1977-2023)

An open communal grazing design is described that enables a large number of grazing tactics to be concurrently evaluated in small plots under common grazing conditions. Pasture data indicated that the same level of utilisation occurred inside the experimental plots as in the surrounding field. However, differential grazing may occur where plots have divergent composition. The open communal design was economical using < 5% of the land, livestock and fencing resources of alternative designs. The limitations of the open communal design as a research tool are also discussed.

Stocking Rate And Supplementation Effects On Performance Of Lambs Grazing Triticale And Ryegrass Sward In Uruguay, R. San Julián, Fabio Montossi, L. Guarino, F. Pittaluga

IGC Proceedings (1977-2023)

An experiment was carried out from 9 June to 2 October 1997, using a Lolium multiflorum Lom. (Ryegrass) and X Triticosecale Wittmack (triticale) sward to evaluate the effect of stocking rate (SR; 20, 30 and 40 lambs/ha), and supplementation (S; with or without) on Corriedale lamb performance. SR had a significant effect on: liveweight gain (160, 130 and 90 g/an/d, P< 0.01); greasy fleece weight (2.8, 2.7 and 2.3 kg, P< 0.01); fiber diameter (28, 27, and 26 microns, P< 0.05); rib eye depth (2.4, 2.1 and 2.0 cm, P< 0.05); fat cover (3.2, 2.1 and 1.5 cm, P< 0.01); hot carcass weight (17.7, 15.6 and 13.5 kg/an, P< 0.01); GR (10.5, 6.6 and 4.2 mm, P< 0.01) and boneless leg weight (1.56, 1.42 and 1.24 kg, P< 0.05), for 20, 30 and 40 lambs per ha, respectively. At the highest SR, lambs increased grazing time (59 vs 52%) and biting rate (29 vs 26 bites/lamb/min). The mayor influence of S on lamb performance was found in grazing behavior variables: (grazing time (63 vs 50%, P< 0.01); biting rate (26.8 vs 28.4 bites/lamb/min, P< 0.01)), carcass characteristics: (hot carcass weight (15.3 vs 16.0 kg, P< 0.05); GR (7.9 and 6.3 mm, P< 0.05)) for with and without supplement, respectively. Over the experimental period (115 days), liveweight production and wool production ranged from 358 to 437 kg/ha for 20 and 30 lambs/ha respectively, and wool production from 55 to 93 kg/ha for 20 and 40 lambs/ha respectively. These results show the potential use of mixed ryegrass and triticale swards to produce high quality lamb meat even at high SRs, and the convenience of using supplements only when sward conditions are not sufficient to maintain an adequate lamb performance, particularly when high lamb SRs are used.

Lamb Stocking Rate And Supplementation Effects On Mixed Triticale And Ryegrass Swards Characteristics, R. San Julián, Fabio Montossi, L. Guarino, F. Pittaluga

IGC Proceedings (1977-2023)

An experiment was carried out from 9 June to 22 October 1997, using a Lolium multiflorum L. (ryegrass) and Triticosecale Wittmack (triticale) mixed sward grazed by lambs in a rotational grazing system, to determine the effect of stocking rate (SR; 20, 30 and 40 lambs/ha) and supplementation (S; with or without) on herbage production, composition and nutritive value. SR affected significantly before and after grazing herbage mass and sward height, being higher the values of these variables at the lower SR (3232, 2611 and 2345 kg DM ha^-1, P < 0.05; 2557, 1761 and 1612 kg DM ha^-1, P < 0.01; 17, 11 and 9 cm, P < 0.01 respectively). Increments in SR had an effect on post grazing sward composition, increasing the proportion of ryegrass (32, 36 and 47 %, P< 0.05) and decreasing triticale contribution (68, 64 and 55 %, P< 0.05) for 20, 30 and 40 lambs/ha. The effect of SR on sward nutritive value was not very clear. Before grazing, S affected significantly herbage mass, being higher the values at the supplemented treatments (2787 vs. 2672 kg DM ha^-1, P < 0.10). This experiment showed the high potential of forage production and nutritive value of ryegrass and triticale swards for lamb production in the sandy soil region of Uruguay, and the dominant effect of SR, compared to S, on most of the sward variables considered.

Putting Light To Work

Thomas Jefferson University Research Magazine

Jefferson researchers are using light in new ways: using blue light to drive chemical processes, and creating products that illuminate in ultraviolet light. Their work reflects a convergence of disciplines such as physics, chemistry, textile engineering and nanotechnology that is driving applications with practical benefits for people and the environment.

John Milligan, PhD, assistant professor of chemical and biological sciences, is leading development of environmentally sustainable ways to spur chemical reactions using blue LED light. The work is an example of the “photoredox” subfield of organic chemistry, which has proven to be an increasingly effective method for building organic molecules. …

Exploring Old Data With New Tricks: Long-Term Monitoring Indicates Spatial And Temporal Changes In Populations Of Sympatric Prairie Grouse In The Nebraska Sandhills, Danielle J. Berger, Jeffrey J. Lusk, Larkin A. Powell, John P. Carroll

School of Natural Resources: Faculty Publications

The contiguous grasslands of the Sandhills region in Nebraska, USA, provide habitat for two sympatric, grassland-obligate species of grouse, the greater prairie-chicken (Tympanuchus cupido pinnatus) and the plains sharp-tailed grouse (Tympanuchus phasianellus jamesi). Collectively referred to as prairie grouse, these birds are monitored and managed jointly by wildlife practitioners who face the novel challenge of conserving historically allopatric species in shared range. We reconstructed region-wide and route-specific prairie grouse population trends in the Sandhills, using a 63-year timeseries of breeding ground counts aggregated from old reports and paper archives. Our objective was to repurpose historical data …