THO-MAC:一种两跳优化的低延迟低功耗无线传感器网络介质访问控制协议

功耗与延迟是无线传感器网络介质访问控制协议设计首要考虑的两个问题。提出了一种新的传感器网络低延迟、低功耗、接收节点初始化异步介质访问控制协议——THO-MAC协议。通过准确预测接收节点的唤醒时间,THO-MAC协议调度发送节点侦听信道,从而减少发送节点空闲侦听能量浪费。THOMAC协议在发送节点两跳转发节点集中选择使报文两跳转发延迟最小的转发节点,从而降低报文传输延迟。使用NS2模拟器对THO-MAC协议进行了详细模拟。模拟结果显示,与RI-MAC和Any-MAC协议相比,THOMAC协议可以减少35.5%和18%的报文传输延迟,同时节省23.5%和15.5%的节点功耗。     

不确定数据流多维建模方法*

由于不确定数据流应用的出现,给传统的精确、静态数据环境下的多维建模带来了巨大挑战。针对不确定数据流动态、无限和不确定等特征,提出了一种不确定数据流多维模型。该模型中引入了不确定对象来描述不确定事实元组,并且通过定义时间维度的层次时间窗口,很好地反映了数据流的动态性和无限性,最后还对此多维不确定数据流模型的基本代数操作和分析代数操作进行了形式化定义,为不确定数据流多维查询与分析提供了理论依据。     

潜艇自航模控制系统设计

为满足自航模操纵性试验的需要,设计了潜艇自航模控制系统的结构,建立了基于TCP/IP的网络通信协议,为保障自航模操纵性实验的安全性,设计了应急处理流程,通过对自航模定深控制过程的分析,完成了升降舵模糊控制器的设计。基于实现的自航模控制系统在操纵性实验中表现良好,对于类似系统的设计与实现具有一定借鉴意义。     

Defense spending and economic growth across the Taiwan straits: a threshold regression model

This paper employs both linear and non‐linear models to investigate the relationship between national defense spending and economic growth for Taiwan and China. Using data from 1953–2000 on defense spending, GDP, import, export and capital, we find that China's defense spending leads that of Taiwan. There exists the phenomenon of an arms race between both countries when official Chinese data are used. On the one hand, feedback relations prevail between economic growth and defense spending growth in Taiwan. On the other hand, China's national defense is found to lead economic growth.     

THE FATE OF DISPUTED TERRITORIES: AN ECONOMIC ANALYSIS

This paper presents a simple model to characterize the outcome of a land dispute between two rival parties using a Stackelberg game. Unlike Gershenson and Grossman (2000 Gershenson, D. and Grossman, H.I. 2000. Civil conflict: ended or never ending?. Journal of Conflict Resolution, 44(6): 807–821.  [Google Scholar]), we assume that the opposing parties have access to different technologies for challenging and defending in conflict. We derive the conditions under which territorial conflict between the two parties is less likely to persist indefinitely. Allowing for an exogenous destruction term as in Garfinkel and Skaperdas (2000 Garfinkel, M. and Skaperdas, S. 2000. Conflict without misperceptions or incomplete information: how the future matters. Journal of Conflict Resolution, 44(6): 793–807. [Crossref], [Web of Science ®] , [Google Scholar]), we show that, when the nature of conflict becomes more destructive, the likelihood of a peaceful outcome, in which the territory’s initial possessor deters the challenging party, increases if the initial possessor holds more intrinsic value for the disputed land. Following Siqueira (2003 Siqueira, K. 2003. Conflict and third‐party intervention. Defence and Peace Economics, 14(6): 389–400. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]), our model has policy implications for peace through third‐party intervention.     

基于云理论一二元语义的雷达装备保障指挥效能评估模型

针对云重心和云模型评判方法存在的信息丢失、难于评判以及信息扭曲等问题,从确定权重等级、评价集和评价结果3个方面对模型进行了改进和完善．应用二元语义确定指标权重,避免了评价信息的丢失和扭曲,采用综合云的思想确定评价集,充分利用评价者给出的信息,简化相似云的理论来定量衡量评价结果,从而建立了基于云理论一二元语义的雷达装备保障指挥效能评估模型．     

频率搅拌混响室内小屏蔽体的场均匀性检验

为了研究频率搅拌混响室内小屏蔽体的屏蔽效能测试方法,需要检验小屏蔽体内的场均匀性．通过对混响室的场均匀性测试方法的研究,提出基于矢量网络分析仪的测试方法,通过计算工作区域任意两点的功率比检验场均匀性,并用该方法检验工作区域内小屏蔽体的场均匀性．实验结果表明：混响室采用扫频信号实现频率搅拌时,放置于工作区域的小屏蔽体内部同样有较好的场均匀性．     

Joint inventory and pricing decisions for perishable products with two‐period lifetime

We consider a periodic review model over a finite horizon for a perishable product with fixed lifetime equal to two review periods. The excess demand in a period is backlogged. The optimal replenishment and demand management (using price) decisions for such a product depend on the relative order of consumption of fresh and old units. We obtain insights on the structure of these decisions when the order of consumption is first‐in, first‐out and last‐in, first‐out. For the FIFO system, we also obtain bounds on both the optimal replenishment quantity as well as expected demand. We compare the FIFO system to two widely analyzed inventory systems that correspond to nonperishable and one‐period lifetime products to understand if demand management would modify our understanding of the relationship among the three systems. In a counterintuitive result, we find that it is more likely that bigger orders are placed in the FIFO system than for a nonperishable product when demand is managed. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013     

单兵遥控武器支架总体方案的设计

单兵武器支架是现代战争中不可或缺的轻型武器平台,该平台可以有效提高作战人员的生存机会。结合当前最先进的微控制器、电机、电机驱动,触摸输入等技术,给出了单兵武器支架的总体方案,详细给出了遥控箱、武器平台的控制方案与框图。     

某小型武器稳定系统的建模及仿真

针对某小型武器稳定系统稳定精度差的问题,构建了其控制系统的数学模型,通过仿真施加试验台架扰动信号,对现系统采用的传统PID控制器进行仿真计算,得到其动态稳定精度,并把得到的和定型试验稳定精度数据对应的外扰模拟信号作为改造后系统的标准扰动输入,对线性自抗扰控制器进行了比对仿真研究.仿真结果表明,系统采用线性自抗扰控制器具有响应速度快、稳定精度高、抗扰能力强的优点.这一方法得到的仿真结果和实车具有较高一致性,可以有效解决实车参数调试困难的问题.