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Effects of Over-Harvesting and Drought on a Predator-Prey System with Optimal Control
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作者 Alanus Mapunda Eunice Mureithi +1 位作者 Nyimvua Shaban Thadei Sagamiko 《Open Journal of Ecology》 2018年第8期459-482,共24页
In this paper, a two species predator-prey model is developed where prey is affected by over-harvesting and drought and predator is affected by drought. The intention is to investigate the impact of over-harvesting an... In this paper, a two species predator-prey model is developed where prey is affected by over-harvesting and drought and predator is affected by drought. The intention is to investigate the impact of over-harvesting and drought on predator-prey system, and suggest control strategies to alleviate the problem of loss of prey and predator species due to over-harvesting and drought. The control strategies suggested are creation of reserve areas with restriction of harvesting for controlling over-harvesting and construction of dams for mitigating drought effects. The results obtained from theoretical and numerical simulation of the predator-prey model with harvesting and drought without control strategies showed that, both harvesting and drought affect the predator-prey population negatively. However, the results obtained from numerical simulations of the model with control measures showed that, the use of control strategies one at a time encourages the increase of the prey and predator species to the optimal population size. Furthermore, the best result is obtained when control strategies, creation of reserve areas with restriction of harvesting and construction of dams are applied simultaneously. 展开更多
关键词 predator-PREY system Over-harvesting DROUGHT Optimal Control
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Periodic Solution for Stochastic Predator-Prey Systems with Nonlinear Harvesting and Impulses
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作者 Yafei Yang Yuanfu Shao Mengwei Li 《Advances in Linear Algebra & Matrix Theory》 2019年第4期89-103,共15页
In this paper, astochastic predator-prey systems with nonlinear harvesting and impulsive effect are investigated. Firstly, we show the existence and uniqueness of the global positive solution of the system. Secondly, ... In this paper, astochastic predator-prey systems with nonlinear harvesting and impulsive effect are investigated. Firstly, we show the existence and uniqueness of the global positive solution of the system. Secondly, by constructing appropriate Lyapunov function and using comparison theorem with an impulsive differential equation, we study that a positive periodic solution exists. Thirdly, we prove that system is globally attractive. Finally, numerical simulations are presented to show the feasibility of the obtained results. 展开更多
关键词 IMPULsEs Perturbations Periodic solution Non-Linear harvestING sTOCHAsTIC predator-PREY systems Globally ATTRACTIVE
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Verification of the Physiological Therapeutic Effects of Harvesting Activities in a Patient with Moderate Alzheimer’s Disease with Long-Term Agricultural Experience
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作者 Kikuo Eguchi Seigo Koura +1 位作者 Nao Eguchi Akihiko Kondou 《Open Journal of Therapy and Rehabilitation》 2024年第3期236-244,共9页
Background: Harvesting activities have proven effective in reducing stress in patients with dementia. At a psychiatric hospital, occupational therapists (OT) made patients with dementia perform vegetable harvesting ac... Background: Harvesting activities have proven effective in reducing stress in patients with dementia. At a psychiatric hospital, occupational therapists (OT) made patients with dementia perform vegetable harvesting activities as a part of their treatment. The patients became calmer and began to smile not only after but also before and during harvesting activity. Therefore, this study aimed to measure autonomic nervous system (ANS) responses over time in a female patient in her 80s with moderate Alzheimer’s disease (AD) who had experience in farming when performing harvesting activities. Additionally, this study aimed to consider factors associated with changes in ANS responses over time and to verify the physiological therapeutic effects of harvesting activities. Methods: An OT with more than 10 years of experience and a good relationship with the patient conducted one-on-one sessions with the patient. Harvesting activity was performed in a courtyard with trees. The patient harvested lettuce (three lettuce plants) grown in a planter while sitting on a chair. Additionally, the planter was set up on a desk. ANS responses were measured over time from before to after the activity for different events at six time periods. Changes in the patient’s ANS responses were assessed during each period. Results: With the involvement of environmental factors and OT during harvesting activities, parasympathetic nervous system (PNS) activity significantly increased. This may lead to improved mental stability. Conclusion: The findings of this study indicate that implementing harvesting activities may have a positive effect on the PNS in patients with AD with long-term agricultural experience. However, further studies with a larger sample size and multidimensional evaluations are needed. 展开更多
关键词 Alzheimer’s Disease Autonomic Nervous Response harvesting Activity Therapeutic Effects
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Prey Predator Fishery Model with Stage Structure in Two Patchy Marine Aquatic Environment
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作者 Mellachervu Naga Srinivas Mantripragada Ananata Satya Srinivas +1 位作者 Kalyan Das Nurul Huda Gazi 《Applied Mathematics》 2011年第11期1405-1416,共12页
In this paper, we propose and analyze a mathematical model to study the dynamics of a fishery resource system with stage structure in an aquatic environment that consists of two zones namely unreserved zone (fishing p... In this paper, we propose and analyze a mathematical model to study the dynamics of a fishery resource system with stage structure in an aquatic environment that consists of two zones namely unreserved zone (fishing permitted) and reserved zone (fishing is strictly prohibited). In this model we introduce a stage structure in which predators are split into two kinds as immature predators and mature predators. It is assumed that immature predators cannot catch the prey and their foods are given by their parents (mature predators). It is also assumed that the fishing of immature predators prohibited in the unreserved zone and predator species are not allowed to enter inside the reserved zone. The local and global stability analysis has been specified. Biological and Bionomical equilibriums of the system are derived. Mathematical formulation of the optimal harvesting policy is given and its solution is derived in the equilibrium case by using Pontryagin’s maximum principle. 展开更多
关键词 PREY predator stage structure Local and Global stability BIONOMIC EQUILIBRIUM Optimal harvestING Pontryagin’s Maximum PRINCIPLE
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开启X4模式金士顿HyperX Predator PCI-ESSD 480GB
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作者 马宇川 《微型计算机》 2015年第16期58-59,共2页
尽管不少M-2固态硬盘在去年就已问世,然而这一产品在实际使用效果上并未显示出非常大的优势。其根本原因在于很多产品只采用了PCI-E2.0x2接口,理论带宽仅比S久rA6Gb/s高40%左右,再加上传输过程中的损耗,其最大连续传输速度也就比... 尽管不少M-2固态硬盘在去年就已问世,然而这一产品在实际使用效果上并未显示出非常大的优势。其根本原因在于很多产品只采用了PCI-E2.0x2接口,理论带宽仅比S久rA6Gb/s高40%左右,再加上传输过程中的损耗,其最大连续传输速度也就比SATA产品高了约200MB/s左右。 展开更多
关键词 金士顿HYPERX predator 多产品 使用效果 传输过程 MB/s sATA 传输速度
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带收获率参数生物模型的Bogdanov-Takens分岔
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作者 傅仙发 《红河学院学报》 2024年第2期132-135,共4页
在生物模型中引入收获率参数,通过分析收获率参数发生微小变化时对生物模型稳定性的影响,给出了生物模型在一个小领域内分岔曲线的平面图和Bogdanov-Takens分岔图.
关键词 收获率 捕食者-食饵模型 稳定性 分岔
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Cymbal Structural Optimization for Improving Piezoelectric Harvesting Efficiency with Taguchi’s Orthogonal Experiment 被引量:1
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作者 Guangqing Shang Wei Ning Chunhua Sun 《Journal of Power and Energy Engineering》 2015年第10期10-15,共6页
To improve piezoelectric harvesting efficiency of Cymbal, optimization design of Cymbal parameters was studied with the method of Taguchi’s orthogonal experiment. The effective factors of piezoelectric harvesting pro... To improve piezoelectric harvesting efficiency of Cymbal, optimization design of Cymbal parameters was studied with the method of Taguchi’s orthogonal experiment. The effective factors of piezoelectric harvesting property were firstly analyzed. The orthogonal experiment schedule was then designed. The finite element model of Cymbal was built via ASPL tool in ANSYS software and static analysis was done. The experimental results were gotten with developed program. The optimization level of each factor was gained. Under the synthetical optimization level of each design factor, the piezoelectric analysis was tested and the open voltage of 236.476 V was revealed with improving 35.73% than the maximum voltage of 174.228 V in the orthogonal experiment. The average voltage of 229.98 V was measured with the manufactured optimized Cymbal structure design. The relative error was 2.54% between simulation and measured data. It indicated that the optimization design schedule was reasonable. Cymbal harvester with the optimized parameters could scavenge larger voltage. 展开更多
关键词 Energy harvest PIEZOELECTRIC Effects CYMBAL harvestER Taguchi’s ORTHOGONAL Experiment
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Parameters Optimization for Piezoelectric Harvesting Energy from Pavement Based on Taguchi’s Orthogonal Experiment Design 被引量:1
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作者 Chunhua Sun Hongbing Wang +1 位作者 Guangqing Shang Jianhong Du 《World Journal of Engineering and Technology》 2015年第4期149-157,共9页
To effectively harvest vibration energy from pavement without affecting driving comfort and safety, parameter optimization was done with the orthogonal experiment design and the finite element analysis. L16(44) Taguch... To effectively harvest vibration energy from pavement without affecting driving comfort and safety, parameter optimization was done with the orthogonal experiment design and the finite element analysis. L16(44) Taguchi’s orthogonal experiments were carried out with planted depth, PZT material, PZT diameter and thickness as optimization parameters and with open voltage and pavement displacement as optimization objectives. The experiment results were obtained via the finite element method. By using range analysis method, the dominance degree of the influencing factors and the optimum condition was obtained for the two objectives, respectively. Further, the multi-objective optimization was performed based on a weight grade method. The combined optimum conditions in order of their dominance degree are PZT diameter 35 mm, PZT thickness 6 mm, planted depth 50 mm and material PZT4. The validity of optimization scheme was confirmed. 展开更多
关键词 PIEZOELECTRIC ENERGY harvestING PAVEMENT Taguchi’s ORTHOGONAL Experiment FINITE Element Method
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Ideal Point Method Applied in Forest Harvest Regulation
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作者 秦安臣 赵林森 +2 位作者 刘建国 李维忠 才丁华 《Journal of Forestry Research》 SCIE CAS CSCD 1997年第2期117-119,共3页
Ideal point method is one of the methods to solve multi-objective problem. It is applied to forest harvest regu-lation, and showed very good results by analyzing changes of quantitative indexes of forest resource stru... Ideal point method is one of the methods to solve multi-objective problem. It is applied to forest harvest regu-lation, and showed very good results by analyzing changes of quantitative indexes of forest resource structure before andafter the regulation. This method can be applied as one of the mathematical tools in forest harvest regulation. 展开更多
关键词 IDEAL point METHOD FOREsT harvest REGULATION FOREsT structure Quantitative index Ohm’s DIsTANCE Equilib-rium ratio
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基于S-SSHI和SECE混合的压电阵列能量俘获电路设计
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作者 熊佳铭 夏银水 +1 位作者 王修登 祁钰耀 《传感技术学报》 CAS CSCD 北大核心 2024年第5期772-782,共11页
串联同步开关电感(Series Synchronous Switch Harvesting on Inductor,S-SSHI)电路输出功率高整流电压范围窄,而同步电荷提取(Synchronous Electric Charge Extraction,SECE)电路则输出功率低整流电压范围宽。提出了一种基于S-SSHI和S... 串联同步开关电感(Series Synchronous Switch Harvesting on Inductor,S-SSHI)电路输出功率高整流电压范围窄,而同步电荷提取(Synchronous Electric Charge Extraction,SECE)电路则输出功率低整流电压范围宽。提出了一种基于S-SSHI和SECE混合的压电阵列能量俘获接口电路,以实现整流器峰值输出功率和最佳整流电压范围之间的平衡。所提出的电路去除了整流桥结构,而采用简单的无源峰值检测器设计,且可以在任意相位差(0~2π)下从多个压电换能器中提取能量。仿真和实验结果表明,所提出的电路具有较高的输出功率和较宽的整流电压范围,与多输入全桥整流器相比,最大输出功率提升了3.04倍。 展开更多
关键词 能量俘获 串联同步开关电感(s-ssHI) 同步电荷提取(sECE) 多压电 自供电
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Harvest of CNPC's Exploration at the Trun of Centry
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作者 Wan Wei Zhao Xianzheng (Exploration Department, CNPC) 《China Oil & Gas》 2000年第1期23-26,共4页
关键词 CNPC harvest of CNPC’s Exploration at the Trun of Centry
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基于BS架构的收割机轨迹数据可视化分析系统 被引量:5
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作者 江楠 马江涛 郑远攀 《农机化研究》 北大核心 2020年第12期188-193,199,共7页
为了提高收割机调度系统的管理水平和农机调度的效率,将B/S架构和可视化分析技术引入到了调度系统的设计中,用户可以直接通过浏览器对远程收割机的轨迹数据进行查看,提高了调度系统的可查询性和可视化水平。改进后的调度系统可以实时显... 为了提高收割机调度系统的管理水平和农机调度的效率,将B/S架构和可视化分析技术引入到了调度系统的设计中,用户可以直接通过浏览器对远程收割机的轨迹数据进行查看,提高了调度系统的可查询性和可视化水平。改进后的调度系统可以实时显示收割机的作业动态和作业轨迹,农机管理人员可以根据作业轨迹合理地对农机作业路径做出规划;当作业的农机较多时,管理人员也可以根据作业区域的面积和特点,对每台农机的作业做出合理的调度。由于采用B/S架构,驾驶人员可以通过浏览器用户端对收割机的作业轨迹充分了解,特别是在遇到急转弯或者障碍物时提前做出预判,从而降低了事故的发生概率。 展开更多
关键词 收割机 行驶轨迹 可视化分析 B/s架构 调度系统
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不同采收期的江苏春柴胡挥发油化学成分的GC-MS分析 被引量:8
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作者 谢东浩 王团结 +1 位作者 欧阳臻 蔡宝昌 《现代中药研究与实践》 CAS 2008年第6期48-51,共4页
目的研究不同采收期的江苏春柴胡挥发油化学成分。方法水蒸气蒸馏法提取江苏春柴胡挥发油,采用气相色谱-质谱联用(GC-MS)技术,分析挥发油的化学成分。结果不同采收期春柴胡挥发油含量差别较大,江苏春柴胡药材以4月中旬采收为宜。结论从... 目的研究不同采收期的江苏春柴胡挥发油化学成分。方法水蒸气蒸馏法提取江苏春柴胡挥发油,采用气相色谱-质谱联用(GC-MS)技术,分析挥发油的化学成分。结果不同采收期春柴胡挥发油含量差别较大,江苏春柴胡药材以4月中旬采收为宜。结论从不同采收期的春柴胡挥发油中均鉴定出n-十六酸,其可以作为春柴胡质量控制中挥发油成分的鉴别特征。 展开更多
关键词 春柴胡 不同采收期 挥发油 GC-Ms 化学成分
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一类具有Beddington-DeAngelis功能反应捕食系统收获模型的稳定性 被引量:4
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作者 韩二东 郑唯唯 罗立贵 《纺织高校基础科学学报》 CAS 2012年第2期145-148,共4页
研究一类具有双线性密度制约及Beddington-DeAngelis功能反应的捕食系统收获模型.运用微分方程定性稳定性理论讨论系统正平衡点的性态,得到其局部渐近稳定及全局渐近稳定的充分条件,利用Pontryagin最大值原理得到系统的最优收获策略.
关键词 Beddington-DeAngelis功能反应 渐近稳定 Pontryagin最大值原理 最优收获策略
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基于T-S模糊神经网络模型对西部村镇集雨窖水水质的评价研究 被引量:5
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作者 齐昕 刘嘉夫 《节水灌溉》 北大核心 2015年第3期28-30,34,共4页
针对西北村镇集雨窖水的水质特点,采用基于T-S模型的模糊神经网络对其进行评价分析。评价分析选用窖水水质指标中的CODMn、NH3-N和DO三个水质指标为输入向量,建立了适用于集雨窖水水质评价的T-S模糊神经网络模型,该模型最大训练误差︱e... 针对西北村镇集雨窖水的水质特点,采用基于T-S模型的模糊神经网络对其进行评价分析。评价分析选用窖水水质指标中的CODMn、NH3-N和DO三个水质指标为输入向量,建立了适用于集雨窖水水质评价的T-S模糊神经网络模型,该模型最大训练误差︱e︱≤0.057 5,具有较强的泛化能力。在实例分析中,得出不同集雨面所收集的集雨窖水水质也不相同;降雨初期集雨窖水水质均为超Ⅴ类,随着时间的增长窖内水质有着明显的改善,但20d内,水质依旧较差且不稳定,需对集雨窖水进行相关处理后才可作为日常生活用水使用。 展开更多
关键词 T-s模糊神经网络 集雨窖水 水质评价
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食饵带收获率的Holling-2型捕食者-食饵模型的Bogdanov-Takens分岔 被引量:1
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作者 傅仙发 蔡高明 陈国雄 《沈阳大学学报(自然科学版)》 CAS 2018年第6期516-518,共3页
为研究食饵带有收获率参数的Holling-2型捕食者-食饵模型的Bogdanov-Takens分岔现象,通过引入了标准中心流形方法,计算得出了生物模型发生余维3Bogdanov-Takens分岔现象的条件,并证明了生物模型的Bogdanov-Takens分岔是退化的.
关键词 收获率 捕食者-食饵模型 Bogdanov-Takens分岔
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EXISTENCE OF TWO PERIODIC SOLUTIONS TO A RATIO-DEPENDENT PREDATOR-PREY MODEL WITH PREDATOR'S HARVEST
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作者 Tian Desheng Wang Mei Zeng Xianwu 《Annals of Differential Equations》 2007年第4期492-498,共7页
In this paper, we study a non-autonomous ratio-dependent predator-prey model with predator's harvest. By means of the coincidence degree theory, we establish sufficient conditions for the existence of at least two po... In this paper, we study a non-autonomous ratio-dependent predator-prey model with predator's harvest. By means of the coincidence degree theory, we establish sufficient conditions for the existence of at least two positive periodic solutions of this model. 展开更多
关键词 predator-prey model RATIO-DEPENDENT predator's harvest periodic solution coincidence degree
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具有脉冲收获的Hassell-Varley型功能性反应捕食系统的周期解存在性
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作者 郭微 高云柱 战英杰 《北华大学学报(自然科学版)》 CAS 2015年第5期567-573,共7页
研究了一类具有脉冲收获和Hassell-Varley型功能性反应的时滞捕食者-食饵系统的周期性问题,利用重合度理论中的Gaines和Mawhin’s延拓定理,建立了该系统至少存在一个正周期解的一组易于验证的充分条件.
关键词 捕食系统 脉冲 时滞 收获率 Hassell-Varley型功能性反应 正周期解
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具有收获率和非线性死亡率的脉冲Nicholoson's blowflies模型正周期解
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作者 姚晓洁 《华南师范大学学报(自然科学版)》 CAS 北大核心 2014年第5期21-25,共5页
研究了一类具有非线性收获率和非线性依赖死亡率的脉冲Nicholoson's blowflies模型.利用重合度理论和不等式分析技巧,获得了该模型至少存在一个正周期解的一些充分条件,对该模型无脉冲情形的相关研究结果进行了推广和研究.此外,给... 研究了一类具有非线性收获率和非线性依赖死亡率的脉冲Nicholoson's blowflies模型.利用重合度理论和不等式分析技巧,获得了该模型至少存在一个正周期解的一些充分条件,对该模型无脉冲情形的相关研究结果进行了推广和研究.此外,给出一个合适的例子来说明所得结果的可行性. 展开更多
关键词 非线性收获率 非线性依赖死亡率 脉冲Nicholson's blowflies模型 正周期解 重合度
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带有Michaelis-Menten型收获项的Lotka-Volterra捕食-食饵模型的稳定性和Hopf分支 被引量:3
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作者 朱致兴 吴然超 刘彪 《西北师范大学学报(自然科学版)》 CAS 北大核心 2019年第2期25-34,共10页
基于种群Lotka-Volterra捕食-食饵模型增长的假设,构建了一个带有食饵收获项的Lotka-Volterra模型.首先探讨了该模型平衡点的存在性和稳定性,然后讨论了一个正平衡点附近产生的Hopf分支,最后通过数值模拟验证了理论分析结果.
关键词 Lotka-Volterra捕食-食饵模型 收获项 稳定性 HOPF分支
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