Sequential learning versus no learning in Bayesian regression models

We consider two regression models: linear and logistic. The dependent variable is observed periodically and in each period a Bayesian formulation is used to generate updated forecasts of the dependent variable as new data is observed. One would expect that including new data in the Bayesian updates results in improved forecasts over not including the new data. Our findings indicate that this is not always true. We show there exists a subset of the independent variable space that we call the “region of no learning.” If the independent variable values for a given period in the future are in this region, then the forecast does not change with any new data. Moreover, if the independent variable values are in a neighborhood of the region of no learning, then there may be little benefit to wait for the new data and update the forecast. We propose a statistical approach to characterize this neighborhood which we call the “region of little learning.” Our results provide insights into the trade‐offs that exist in situations when the decision maker has an incentive to make an early decision based on an early forecast versus waiting to make a later decision based on an updated forecast. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 532–548, 2014     

The sixteenth-century antecedents of special operations ‘small war’

The first conceptual, theoretical treatises about small war (la petite guerre) as special operations appeared only from the middle of the seventeenth century. The term is not used in the eighteenth-century sense of ‘special operations’ in older sources. The supposed absence of any treatment of the subject is surprising considering the obsession with the ‘art of war’ in the Renaissance, but other authors attribute it to a supposed antinomy between chivalric ideals and irregular warfare. But the absence of explicit manuals on the subject is not evidence of absence of advanced reflection on this kind of operations in the Middle Ages and in Early Modern times. We should thus look elsewhere, in other genres, for writings that contain and pass on military knowledge. Epics, romances, educational and military treatises, and memoirs in fact contain elements of a theory of special operations, even though these genres differ from our conception of rationality inherited from the Enlightenment.     

鱼雷贮存战备完好率模型

为了评估鱼雷综合特性参数鱼雷贮存战备完好率,分析了国军标中基本模型,对照鱼雷寿命剖面,指出基本模型在具体鱼雷装备中应用存在的不足;通过对鱼雷寿命剖面中的基层级维修的深入分析,综合考虑贮存可靠度、故障检测率、鱼雷故障修复概率与备件满足率,给出了一个LRU故障、多个相同LRU故障以及多个不同LRU故障时的战备完好率模型。并通过计算验证了该模型的有效性。     

Guerrillas and bandits in the Serranía de Ronda, 1810–1812

The Spanish Guerrilla (1808–1812) which has given its name to ideologically motivated insurgencies is usually portrayed as a patriotic uprising against the French occupation forces of Napoleon. It was that, in part, but also many other things besides. This case study illustrates its overlap and convergence with banditry but also with social unrest turned into uprisings directed by poor Spaniards against their creditors, as in the storming of Ronda by insurgents in 1810. From the propaganda of the day to the subsequent Spanish patriotic historiography, there has been a tendency to exaggerate the amplitude of events and also the damage that was done to the French forces and the casualty figures inflicted on them.     

基于半实装的无人机模拟训练系统研究与设计

针对传统面向无人机地面操控手测控训练任务的模拟训练系统存在的缺点,分析了面向无人机地面操控人员测控训练任务的主要特点,提出了一种基于实装地面测控站的无人机半实物仿真训练系统结构框架,设计了典型无人机模拟训练系统的结构层次和系统运行模式,与传统面向地面操控手的无人机仿真训练系统相比,所提出的仿真系统架构具有逼真度高、易于实现和复用、开发技术成熟等优点,在提高训练效率、节省训练成本方面具有重要应用价值。     

电驱动装甲车辆双重转向控制联合仿真

为了提高轮毂电机驱动装甲车辆转向的灵活性及越野机动性能,借鉴履带车辆滑移转向思想,采用双重转向控制策略。以车辆的横摆角速度为控制目标,设计了自抗扰控制器,通过调整两侧轮毂电机转矩输出产生直接横摆力矩,进而调节车辆横摆角速度,实现装甲车辆双重转向。在Adams中建立车辆动力学模型的基础上,构建Adams与Matlab环境中的联合仿真模型,并进行了联合仿真,结果表明,基于直接横摆力矩控制的双重转向增大了外侧动力输出,减小了车辆在中低速转向时转向半径,提高了车辆的转向性能。     

基于故障率和设计特性动态加权的维修性分配法

针对国军标中"按故障率和设计特性的维修性分配方法",当可更换单元故障率相差较大时,分配结果与实际明显不符的问题,采用动态加权模型,对国军标的分配方法进行了改进,提出了"基于故障率和设计特性动态加权的维修性分配法",弥补了国军标分配方法的不足。通过理论分析、论证、算例比较和维修性试验验证,证明该方法合理可行。     

两栖作战环境下装甲突击车战斗效能指数计算

分析了两栖装甲突击车战斗效能指标体系,战斗效能主要由攻击能力、机动能力、防护能力、指挥通信能力组成。根据海陆作战环境的特点,分别提出了陆上作战和海上作战的战斗效能指标体系。研究了海陆作战环境下的两栖装甲突击车战斗效能指数的计算方法,并分别计算攻击、机动、防护、指挥通信各能力的指数和系数。最后,通过实例计算分析,结果表明该方法计算各型两栖装备的效能指标基本符合实际情况,可用于装备作战使用研究和作战模拟系统。     

舰炮对空射击无线电近炸引信作用范围定量分析

舰炮对空射击时,对无线电近炸引信作用范围的研究,是评估装有无线电引信炮弹射击效能的基础.为探索舰炮对空射击时,无线电近炸引信的作用规律,在深入分析无线电近炸引信动作特点的基础上,采取定量分析的方法,研究了无线电近炸引信的作用机理.为定量分析无线电近炸引信的作用范围和评估装有无线电引信炮弹的射击效能提供科学的方法和手段.     

随机理论雷达探测地面目标模型

雷达对地面目标的搜索效能是直升机对地作战效能评估的基础,建立雷达对地面目标搜索的数学模型,并分析几个因素对发现目标概率的影响,以及提高目标发现概率的方法,进而提高直升机的作战效能.模型有效地提高了雷达探测地面目标效能评估的准确性,对于指挥决策部门和设计单位有一定的参考意义.