针对无线可充电传感器网络(WRSN)中的节点死亡率过高问题,为了降低节点死亡率,以按需充电架构为基础,提出了一种动态不均匀分簇的单移动充电设备(MC)多节点在线充电策略SMMCS(single MC multi-node charging strategy)。策略首先将无线...针对无线可充电传感器网络(WRSN)中的节点死亡率过高问题,为了降低节点死亡率,以按需充电架构为基础,提出了一种动态不均匀分簇的单移动充电设备(MC)多节点在线充电策略SMMCS(single MC multi-node charging strategy)。策略首先将无线可充电传感器网络进行动态不均匀分簇,以此划分移动充电设备的服务分区;然后在此模型基础上以最小网络节点死亡率为目标,进行路径规划时综合考虑节点剩余能量、距离以及能耗等因素。仿真实验结果表明,与SAMER、VTMT以及FCFS策略相比,该策略减少了节点等待时间,缩短了MC总充电代价,减小了节点死亡率。基于仿真条件,网络节点死亡率为4.31%。展开更多
The aim of this study was to observe the morphological changes of muscle in the process of rigor mortis. The quadriceps of 40 rats at various postmortem intervals were observed under the...The aim of this study was to observe the morphological changes of muscle in the process of rigor mortis. The quadriceps of 40 rats at various postmortem intervals were observed under the scanning electron microscope(SEM) and the light microscope by phosphotungstic acid haematoxylin(PTAH) stain. The results showed that the striations of muscle were blurred within 4 h, but they became apparent from 6 h to 24 h after death. The authors suggest that this phenomenon be associated with the increased resistance of muscle against the postmortal changes. The observations by scanning electron microscopy and light microscopy have revealed that the muscles do contract in the process of rigor mortis because the distance between two Z lines shortens and the I band narrows, compared with those in anaesthetised animals. The basic biochemical process for the formation of rigor mortis is the same as that of muscle contraction except that the former happens postmortem and the latter antemortem.展开更多
Delay/disruption tolerant networking （DTN） is an approach to networking where intermittent connectivity exists： it is often afforded by a store and forward technique. Depending on the capability of intermediary nod...Delay/disruption tolerant networking （DTN） is an approach to networking where intermittent connectivity exists： it is often afforded by a store and forward technique. Depending on the capability of intermediary nodes to carry and forward messages, messages can be eventually delivered to their destination by mobile nodes with an appropriate routing protocol. To have achieved a successful delivery, most DTN routing protocols use message duplication methods. Although messages are rapidly transferred to the destination, the redundancy in the number of message copies increases rapidly. This paper presents a new routing scheme based on a stochastic process for epidemic routing. Message redundancy is efficiently reduced and the number of message copies is controlled reasonably. During the contact process of nodes in the network, the number of message copies changes, and according to the variability in the number of copies, we construct a special Markov chain, birth and death process, on the number of message copies then calculate and obtain a stationary distribution of the birth and death process. Comparing the theoretical model with the simulation we have performed we see similar results. Our method improves on time-to-live （TTL） and antipacket methods, in both redundancy and delivery success efficiency.展开更多
Zn neural networks, both excitatory and inhibitory cells play important roles in determining the functions of systems. Various dynamical networks have been proposed as artificial neural networks to study the propertie...Zn neural networks, both excitatory and inhibitory cells play important roles in determining the functions of systems. Various dynamical networks have been proposed as artificial neural networks to study the properties of biological systems where the influences of excitatory nodes have been extensively investigated while those of inhibitory nodes have been studied much less. In this paper, we consider a model of oscillatory networks of excitable Boolean maps consisting of both excitatory and inhibitory nodes, focusing on the roles of inhibitory nodes. We find that inhibitory nodes in sparse networks （smM1 average connection degree） play decisive roles in weakening oscillations, and oscillation death occurs after continual weakening of oscillation for sufficiently high inhibitory node density. In the sharp contrast, increasing inhibitory nodes in dense networks may result in the increase of oscillation amplitude and sudden oscillation death at much lower inhibitory node density and the nearly highest excitation activities. Mechanism under these peculiar behaviors of dense networks is explained by the competition of the duplex effects of inhibitory nodes.展开更多
文摘针对无线可充电传感器网络(WRSN)中的节点死亡率过高问题,为了降低节点死亡率,以按需充电架构为基础,提出了一种动态不均匀分簇的单移动充电设备(MC)多节点在线充电策略SMMCS(single MC multi-node charging strategy)。策略首先将无线可充电传感器网络进行动态不均匀分簇,以此划分移动充电设备的服务分区;然后在此模型基础上以最小网络节点死亡率为目标,进行路径规划时综合考虑节点剩余能量、距离以及能耗等因素。仿真实验结果表明,与SAMER、VTMT以及FCFS策略相比,该策略减少了节点等待时间,缩短了MC总充电代价,减小了节点死亡率。基于仿真条件,网络节点死亡率为4.31%。
文摘The aim of this study was to observe the morphological changes of muscle in the process of rigor mortis. The quadriceps of 40 rats at various postmortem intervals were observed under the scanning electron microscope(SEM) and the light microscope by phosphotungstic acid haematoxylin(PTAH) stain. The results showed that the striations of muscle were blurred within 4 h, but they became apparent from 6 h to 24 h after death. The authors suggest that this phenomenon be associated with the increased resistance of muscle against the postmortal changes. The observations by scanning electron microscopy and light microscopy have revealed that the muscles do contract in the process of rigor mortis because the distance between two Z lines shortens and the I band narrows, compared with those in anaesthetised animals. The basic biochemical process for the formation of rigor mortis is the same as that of muscle contraction except that the former happens postmortem and the latter antemortem.
文摘Delay/disruption tolerant networking （DTN） is an approach to networking where intermittent connectivity exists： it is often afforded by a store and forward technique. Depending on the capability of intermediary nodes to carry and forward messages, messages can be eventually delivered to their destination by mobile nodes with an appropriate routing protocol. To have achieved a successful delivery, most DTN routing protocols use message duplication methods. Although messages are rapidly transferred to the destination, the redundancy in the number of message copies increases rapidly. This paper presents a new routing scheme based on a stochastic process for epidemic routing. Message redundancy is efficiently reduced and the number of message copies is controlled reasonably. During the contact process of nodes in the network, the number of message copies changes, and according to the variability in the number of copies, we construct a special Markov chain, birth and death process, on the number of message copies then calculate and obtain a stationary distribution of the birth and death process. Comparing the theoretical model with the simulation we have performed we see similar results. Our method improves on time-to-live （TTL） and antipacket methods, in both redundancy and delivery success efficiency.
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10975015 and 11174034the Fundamental Research Funds for the Central Universities
文摘Zn neural networks, both excitatory and inhibitory cells play important roles in determining the functions of systems. Various dynamical networks have been proposed as artificial neural networks to study the properties of biological systems where the influences of excitatory nodes have been extensively investigated while those of inhibitory nodes have been studied much less. In this paper, we consider a model of oscillatory networks of excitable Boolean maps consisting of both excitatory and inhibitory nodes, focusing on the roles of inhibitory nodes. We find that inhibitory nodes in sparse networks （smM1 average connection degree） play decisive roles in weakening oscillations, and oscillation death occurs after continual weakening of oscillation for sufficiently high inhibitory node density. In the sharp contrast, increasing inhibitory nodes in dense networks may result in the increase of oscillation amplitude and sudden oscillation death at much lower inhibitory node density and the nearly highest excitation activities. Mechanism under these peculiar behaviors of dense networks is explained by the competition of the duplex effects of inhibitory nodes.
