Battery-Aware Routing for Streaming Data Transmissions in Wireless Sensor Networks

Recent technological advances have made it possible to support long lifetime and large volume streaming data transmissions in sensor networks. A major challenge is to maximize the lifetime of battery-powered sensors to support such transmissions. Battery, as the power provider of the sensors, therefore emerges as the key factor for achieving high performance in such applications. Recent study in battery technology reveals that the behavior of battery discharging is more complex than we used to think. Battery powered sensors might waste a huge amount of energy if we do not carefully schedule and budget their discharging. In this paper we study the effect of battery behavior on routing for streaming data transmissions in wireless sensor networks. We first give an on-line computable energy model to mathematically model battery discharge behavior. We show that the model can capture and describe battery behavior accurately at low computational complexity and thus is suitable for on-line battery capacity computation. Based on this battery model we then present a battery-aware routing (BAR) protocol to schedule the routing in wireless sensor networks. The routing protocol is sensitive to the battery status of routing nodes and avoids energy loss. We use the battery data from actual sensors to evaluate the performance of our protocol. The results show that the battery-aware protocol proposed in this paper performs well and can save a significant amount of energy compared to existing routing protocols for streaming data transmissions. Network lifetime is also prolonged with maximum data throughput. As far as we know, this is the first work considering battery-awareness with an accurate analytical on-line computable battery model in sensor network routing. We believe the battery model can be used to explore other energy efficient schemes for wireless networks as well.     

国有公路运输企业改革创效的现实选择

通过对公路运输企业经营实践的考察 ,介绍了国有公路运输企业改革创效的一些现实选择 ,以供运输公司经营借鉴 ,从而摆脱困境 ,取得良好业绩     

裂齿矩形翅片板翅式换热器优化设计的分析

对裂齿矩形翅片板翅式换热器中的裂齿矩形翅片的传热效率作了分析,并以单位质量材耗的换热能力最大为目标函数,分析研究了在不同雷诺数(Re)的操作条件下裂齿矩形翅片间角度、翅片厚、长度、宽度及极厚之间的关系。结果表明:在气体换热的场合下,当Re在某一范围时翅片可有效地起到强化传热的作用。当板厚为5mm,翅片厚为3mm,翅片间夹角为45°～70°,Re为2×10~3～8×10~3,最佳翅片纵向间距与翅片长度和翅片厚度乘积的平方根的比为1.5～2.5,最佳翅片尺寸系数为3～5时,传热强化效果较好。     

Experience, Context, and the Visual Perception of Human Movement.

Why are human observers particularly sensitive to human movement? Seven experiments examined the roles of visual experience and motor processes in human movement perception by comparing visual sensitivities to point-light displays of familiar, unusual, and impossible gaits across gait-speed and identity discrimination tasks. In both tasks, visual sensitivity to physically possible gaits was superior to visual sensitivity to physically impossible gaits, supporting perception-action coupling theories of human movement perception. Visual experience influenced walker-identity perception but not gait-speed discrimination. Thus, both motor experience and visual experience define visual sensitivity to human movement. An ecological perspective can be used to define the conditions necessary for experience-dependent sensitivity to human movement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

会计政策选择的效率性分析

会计政策选择类型在理论上大体可分为机会主义型和效率(或有效契约)型。会计政策选择具有效率性,但也为经理人员的机会主义行为打开了大门。在我国,由于企业缺乏一系列有效的激励约束机制,会计政策选择的机会主义仍然严重。为此,必须建立适合我国企业有效的激励约束机制。     

氧化铝熟料单筒冷却机节能技术改造

本对影响氧化铝熟料单筒冷却机冷却效率的因素进行了分析，并提出了相应的节能技术改造措施，取得了明显的节能效益。     

大型储罐基础非平面倾斜问题的探讨

大型储罐因基础产生非平面倾斜而影响其正常使用的情况在工程中时有发生,文章通过对某油罐工程中基础沉降观测结果的分析,探讨了储罐基础产生非平面倾斜的原因。相邻储罐之间的相互影响、充水预压未达到规范要求以及地基处理措施不当是引起储罐基础非平面倾斜的主要因素。针对相邻储罐间的相互影响,根据现行《石油化工企业设计防火规范》和《石油化工企业钢储罐地基与基础设计规范》的规定,提出以下建议:储罐布置的净距除应满足防火规范规定外,有条件时也应适当考虑对基础沉降的影响,当采用复合地基时,相邻储罐间的净距不宜小于0.6 D;当占地面积成为主要矛盾,储罐间的净距只能限制在防火规范规定的最小范围时,在地基处理时就应采取有效措施,以尽可能减少相邻储罐的相互影响。     

井冈山水厂设计体会

阐述水厂设计中对水厂规模、水源地、净水厂位置及净水工艺的确定过程，根据原水的特点，通过分析对无阀滤池进行改良。     

预测水驱油田开发动态的一种方法

水驱曲线法和数学模型法都是油藏工程中的重要方法，前者主要用于在一定的经济含水条件下预测水驱油田的可采储量和采收率，后者主要用于预测不同类型油田的产量、累积产量和一定经济极限产量下的可采储量。然而，前者与时间序列无关，后者与含水率序列无关，都有局限性。提出丙型水驱曲线公式与ＨＣＺ数学模型公式联解预测法，不但可以预测水驱油田产量、累积产量、含水率随时间的变化，还可预测可采储量、可动油储量和水驱波及体积系数的变化。图３表１参１２（陈志宏摘）