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基于能量自采集的无线传感器网络网关切换机制研究 被引量:5
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作者 杜文振 陈海明 +1 位作者 李栋 崔莉 《高技术通讯》 CAS CSCD 北大核心 2016年第7期631-642,共12页
针对野外传感网系统中采用太阳能供电的网关因天气变化而产生能量供给失效的问题,研究了基于历史能量采集信息和实时气象信息的多网关切换方法。首先基于气象信息决定需要切换的网关和网关切换的时机;其次提出了一种网关选择算法(Easi G... 针对野外传感网系统中采用太阳能供电的网关因天气变化而产生能量供给失效的问题,研究了基于历史能量采集信息和实时气象信息的多网关切换方法。首先基于气象信息决定需要切换的网关和网关切换的时机;其次提出了一种网关选择算法(Easi GS),根据候选网关剩余工作时间让节点先验式选择网关接入,以避免网关失效带来的数据丢失问题,并通过最优网关接入方法降低系统中采集节点的整体能耗;最后根据实际应用关注的数据发送频率、网关恢复时间、节点与候选网关之间的传输距离等信息,通过概率统计的方法对Easi GS的计算开销进行了进一步优化。仿真实验表明,Easi GS能使系统整体能耗达到最优,并且优化后的Easi GS能够有效降低节点上的计算量。 展开更多
关键词 环境监测 太阳能供电网关 网关切换方法 网关选择算法 能量恢复时间 概率统计
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Firmness measurement of peach by impact force response 被引量:2
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作者 Yong-wei WANG Jun WANG Chong YAO Qiu-jun LU 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2009年第12期883-889,共7页
The impact force response of a peach impacting on a metal flat-surface was considered as nondestructive determination of firmness. The objectives were to analyze the effect of firmness, drop height, fruit mass, and im... The impact force response of a peach impacting on a metal flat-surface was considered as nondestructive determination of firmness. The objectives were to analyze the effect of firmness, drop height, fruit mass, and impact orientation on the impact force parameters, and to establish a relationship between the impact force parameter and firmness. The effect of fruit firmness, drop height and fruit mass on the impact force parameters (coefficient of restitution, percentage of energy absorbed, and coefficient of force-time) was evaluated. The study found that the coefficient of restitution, percentage of energy absorbed, and force-time impact coefficient were significantly affected by fruit ripeness, but not affected by drop height, impact position (fruit cheek), and mass. The percentage of absorbed energy increased with ripeness, while the force-time impact coefficient and coefficient of restitution decreased with ripeness. Relationships were obtained between the three impact characteristic parameters (force-time impact coefficient, coefficient of restitution, and percentage of energy absorbed) and peach firmness using a polynomial model (R2=0.932), S model (R2=0.910), and exponential model (R2=0.941), respectively. 展开更多
关键词 FIRMNESS PEACH Impact force Coefficient of restitution Percentage of absorbed energy
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