Location and calculation-free node-scheduling schemes in large wireless sensor networks

In wireless sensor networks that consist of a large number of low-power, short-lived, unreliable sensors, one of the main design challenges is to obtain long system lifetime without sacrificing system original performance (sensing coverage and sensing reliability). To solve this problem, one of the potential approaches is to identify redundant nodes at the sensing interface and then assign them an off-duty operation mode that has lower energy consumption than the normal on-duty mode. In our previous work [J. Wireless Commun. Mobile Comput. 3 (2003) 271; Processing of ACM Wireless Sensor Network and Application Workshop 2002, September 2002], we proposed a node-scheduling scheme, which can provide a 100% sensing coverage preservation capability. This, however, requires each node to be aware of its own and its neighbors’ location information. Also, in that scheme, each node has to do accurate geometrical calculation to determine whether to take an off-duty status. In this paper, we propose and study several alternative node-scheduling schemes, which cannot completely preserve the original system coverage, but are nonetheless light-weighted and flexible compared with the previous one. Our simulation results compare these schemes with the previous one and demonstrate their effectiveness.     

基于多代理技术的传感器管理系统

针对分布式对空监视网中混合式传感器管理结构存在的问题，提出了基于多代理技术的混合式传感器管理结构。该结构较好地克服了混合式管理结构中在融合中心存在的瓶颈问题，通过多个传感器代理、融合中心代理之间的相互协商来实现传感器任务的分配。传感器代理与传感器相结合使传感器的工作模式实现高度的自动化和模块化，便于传感器的灵活组网。     

空间交会对接用激光雷达敏感器

本文讨论了在航天飞行器的空间交会对接(RVD)技术中采用激光雷达敏感器的可行性。提出在航天飞行器的自主交会对接技术中,应采用一种简单、实用的单目标系统。     

光纤机敏结构制作方法的研究

本文讨论机敏结构的制作方法、集成光纤传感器存在的问题、现有解决方法和今后的研究方向。     

光纤传感器在海洋环境监测中的应用

海洋是个特殊的环境,为许多光纤传感器提供了一个极好的应用领域。对于海洋这个特殊的“敌对”环境,光纤传感器将面临许多挑战。 本文着重介绍应用于海水温度、浊度、盐份浓度、浮游生物和溶解物光吸收量以及环境湿度等海洋环境参数监测的光纤传感器的原理、结构和特性,展望光纤传感器在海洋环境监测方面的美好前景。     

用于曲面精密检测的新型光纤三角传感器研究

基于光纤传感技术和三角测量方法，提出了一种用于曲面检测的新型光纤三角传感器。根据所设计的轮辐式接收光纤结构，可以在测量曲面与传感头间位移时，首先获取被测点处微面元的倾斜信息，以便对传感器测量值进行实时误差修正，从而解决了被测表面倾斜对坐标测量带来的影响。该传感器还能有效地消除环境光干扰、光源波动、表面反射率变化等对测量带来的影响。建立了传感器测量的数学模型。理论分析和初步的实验结果证明了系统的有效性和实用性。该传感器系统不稳定性好于0.3%，横向分辨率好于8μm，高度分辨率好于0.1μm。     

Optical current transducer with bulk type Bi12SiO20 faraday sensor for power systems

Two types of optical current transducers (OCTs) have a bulk Faraday sensor inserted into the gap of an iron core and a porcelain insulator with optical fiber. The sensor consists of Bi₁₂SiO₂₀ (BSO) single crystal, a polarizer, and an analyzer. The OCTs satisfied the target performance requirement for fault location and metering and demonstrated maintained performance at some power utilities in Japan and the US. We have developed a fault location system that immediately detects the fault current with the OCTs, there by locating the fault section. The OCT can easily replace the existing support insulators for the disconnecting switch without any modifications to structure height or bus-bar. For metering requiring 0.3% class accuracy, use of a BSO with right optical rotatory power combined with BSO with left optical rotatory power results in a Faraday sensor with improved temperature characteristics. The OCT demonstrated 0.3% class accuracy for metering described in the current transformer Specifications of IEEE C57–13, 1993.     

光纤液位传感器检测原理探讨

叙述光纤液位传感器在贮油罐中的应用,提出实验所采用的方案。推导出液面高度公式,比较实现检测的两种电路的优缺点,同时对实验精度和测量范围进行了讨论。     

On Two Parallel Matched Gratings Demodulation Method of Fiber Grating Strain Sensor

The method of demodulation with two parallel matched fiber Bragg gratings( FBGs)system is introduced to enlarge the range of strain that can be detected by the FBG sensor system.     

求解无线传感器网络路由问题的蚁群最优化算法及其收敛性

首先将无线传感器网络的路由问题转化成求解最小Steiner树问题,然后给出了求解无线传感器网络路由的蚁群优化算法,并对算法的收敛性进行了证明．最后对找到最优解后信息素值的变化进行了分析．即在限制信息素取值的条件下,当迭代次数充分大时,该算法能以任意接近于1的概率找到最优解,并且当最优解找到后,最优树边上的信息素单调增加,而最优解以外边上的信息素在有限步达到最小值．