Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks

无线传感器网络，作为全球未来十大技术之一，集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术，可实时感知、采集、处理、传输网络分布区域内的各种信息数据，在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议，并针对大规模的无线传感器网络设计了一种树状路由协议，它根据节点地址信息来形成路由，从而简化了复杂繁冗的路由表查找和维护，节省了不必要的开销，提高了路由效率，实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR（AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位：工学硕士院系专业：信息科学与技术学院通信工程系_通信与信息系统学号：2332007115216

Research on the interaction of microwaves with snow and ice. Part I. A study on the microwave backscattering from melting snowpack

The primary objective of this paper is to obtain the basic data on the interaction between microwaves and natural snowpack in the melting season using 9.37GHz and 31.5GHz microwaves. The diurnal variations of the back scatter from snowpack were measured through microwave sensors placed above the surface. The obtained results indicated periodic changes in the daytime and relatively monotonous changes in the nighttime. These results suggest that the interference occurred between the reflective wave from snowpack and the original transmitting wave. In order to confirm these periodic changes of the back scatter, laboratory experiments were carried out by the use of artificially wetted snow

MAGNETIC RESONANCE IMAGING AND PATHOLOGIC STUDIES ON LATERAL FLUID PERCUSSION INJURY AS A MODEL OF FOCAL BRAIN INJURY IN RATS

In this study, morphologic changes in brain lesions initiated by moderate lateral fluid percussion injury in rats were investigated chronologically using high resolution magnetic resonance imaging (MRI) and histopathologic methods. Rats were subjected to moderate fluid percussion injury (average 2.80±0.48 atmospheres) over the exposed dura overlying the right parietal cortex. MRI obtained in vivo were compared with corresponding pathologic findings at 1, 6, and 24 h and at 3, 6,14 and 80 days after injury. T2 weighted images showed scattered low signal intensity in the injured cortex within a few hours after injury, whereas histologic findings revealed intraparenchymal hemorrhages. T2-weighted images of the ipsilateral cerebral cortex and/or corpus callosum showed a high-signal-intensity area 4 h after injury. The high-signal-intensity area became largest in size between 6 and 24 h, then declined gradually, and almost disappeared 14 days after injury. Histologic examination revealed pyknosis, retraction of the cell body of neurons with vacuolated neuropil in the corresponding regions 6 and 24 h after injury, and cystic necrosis 14 days after injury. The location and extent of these pathologic changes were depicted accurately by MRI in vivo. In the hippocampus, pyknosis and retraction of the cell body of pyramidal neurons were observed on the injured side 24 h after injury, and the number of neurons in the CA1 and CA2『 CA3 regions decreased significantly on the same side by 14 days after injury. It is concluded that morphologic changes in the brain following experimental traumatic brain injury in rats are detectable in υivo by high-resolution MRI, and that MRI may be useful for the evaluation of treatment effects in experimental brain injury