1553B数据总线的使用效率

在1553B 总线的应用中,有两个关键问题:数据总线的使用和传输信息的标准化。本文研究了在连接WPS—1系统中的这些问题,主要内容包括:推论出数据总线能力的计算公式和计算数据WPS—1系统的的计算数据总线能力,除了解决与WPS—1系统有关的问题外,也试着对另外一些类似问题建立一个总的分析方法。     

信号采样及频谱分析在线信道测试中的应用

用AD采集卡对指控系统有线信道中的连续时间信号进行采样,得到离散的时间信号,再运用一种离散傅立叶变换——CZT进行频谱分析。详细介绍了在给定测量范围和精度的要求下,采集卡工作参数的配置方法,以及CZT变换实现频域细化的原理和计算参数的选定,还提出了一种快速算法,以增强测试系统的实时性。     

Balancing stability and efficiency in team formation as a generalized roommate problem

The assignment of personnel to teams is a fundamental managerial function typically involving several objectives and a variety of idiosyncratic practical constraints. Despite the prevalence of this task in practice, the process is seldom approached as an optimization problem over the reported preferences of all agents. This is due in part to the underlying computational complexity that occurs when intra-team interpersonal interactions are taken into consideration, and also due to game-theoretic considerations, when those taking part in the process are self-interested agents. Variants of this fundamental decision problem arise in a number of settings, including, for example, human resources and project management, military platooning, ride sharing, data clustering, and in assigning students to group projects. In this article, we study an analytical approach to “team formation” focused on the interplay between two of the most common objectives considered in the related literature: economic efficiency (i.e., the maximization of social welfare) and game-theoretic stability (e.g., finding a core solution when one exists). With a weighted objective across these two goals, the problem is modeled as a bi-level binary optimization problem, and transformed into a single-level, exponentially sized binary integer program. We then devise a branch-cut-and-price algorithm and demonstrate its efficacy through an extensive set of simulations, with favorable comparisons to other algorithms from the literature.     

箔条云干扰下的单目标恒虚警率检测研究

箔条云在扩散过程中随着时间变化会稀释和扩大,其回波特性会发生改变,被检测目标与箔条的相互位置关系也会影响雷达恒虚警检测。针对作战对抗过程中箔条干扰易造成雷达接收机阻塞干扰目标检测,检测概率迅速降低且易丢失目标贻误战机,通过详细分析箔条的扩散过程及信号频谱特性及其箔条云和目标的两种位置关系,利用恒虚警处理算法在噪声基底为10 dB和20 dB情况下对目标进行恒定虚警率检测研究。研究结果对改善飞机检测性能和抗虚警能力以及提高战场生存率具有积极作用。     

逆变器-异步电机电磁噪声的分析与研究

利用Ansoft建立了样机的二维模型,计算了样机在空载运行下的各性能参数,分析了样机内的磁场分布情况.在此基础上,计算了负载大小、机壳设计尺寸和逆变器供电对异步电机电磁噪声的影响.仿真分析表明:通过合理改变机壳尺寸和质量以及选择合适的逆变器开关频率的方法可实现异步电机的降噪.     

Alternative models of Greek defence expenditures

This paper models and estimates Greek defence spending over the 1950–1989 period. It employs the Stone‐Geary welfare function and estimates levels of defence expenditures by the Engle‐Granger two‐step procedure. The Dickey‐Fuller test regression for cointegration is specified in terms of the significance of additional augmentations. The Deaton‐Muellbauer functional form is then employed and an estimating equation for the expenditure share of defence is derived. This specification is compared with the levels equation through a number of non‐nested tests involving model transformation.     

The effect of deployment on first‐ and second‐term re‐enlistment in the US active duty force

Why should deployment affect re‐enlistment? In our model, members enter the military with naïve beliefs about deployment and use actual deployment experience to update their beliefs and revise their expected utility of re‐enlisting. Empirically, re‐enlistment is related to the type and number of deployments, consistent with the learning model. Non‐hostile deployment increases first‐term re‐enlistment but hostile deployment has little effect except for the Army, where the effect is positive. Both types increase second‐term re‐enlistment. Interestingly, first‐term members with dependants tend to respond to deployment like second‐term members. In addition, deployment acts directly to affect re‐enlistment, not indirectly through time to promotion.     

基于Sub-Nyquist采样的单通道频谱感知技术

宽带频谱感知技术在认知无线电中具有广泛的应用。基于时分的思想,将信号采集时间以固定长度的时间片进行划分,分别与不同的伪随机码信号相乘,经过低通滤波和sub-Nyquist采样,利用采样数据求出信号的频率支集。与已有的多通道频谱感知结构相比,本文用相对简单的单通道结构实现,同样能够利用低速率的采样点完成频谱感知。仿真实验结果表明,在信号的频率支集未知的情况下,该算法能够有效利用sub-Nyquist采样的数据实现频谱感知。     

基于最大比合并的循环平稳频谱协作检测

多天线空间分集和多用户协作检测是提高认知无线电频谱检测性能的2种关键技术,由此提出了基于循环平稳特征的多天线多用户频谱协作检测方法.首先接收器在频域按照最大比合并的方法合并各天线接收信号,对合并信号进行初步频谱判决.然后在多用户中按照K/N融合准则进一步做频谱协作检测.仿真分析表明,综合利用信号循环平稳特征和协作检测技术可有效改善认知无线电系统检测性能.     

部分频带干扰下伪码跟踪误差分析

为精确分析部分频带干扰下伪码跟踪误差,需要考虑伪码的非理想随机特性。引入伪码的精细功率谱模型,对比分析了不同带宽干扰下基于简化谱和精细谱的码跟踪误差。定义了相对误差系数,用以定量描述伪码非理想随机特性对码跟踪误差的影响。当干扰带宽增大时,相对误差系数逐渐减小,伪码非理想随机特性对码跟踪误差的影响逐渐减小,基于简化谱的分析趋近于基于精细谱的分析。结合GPS L1 C/A码,给出了相对误差小于0.2的最小干扰带宽,并将其作为基于简化谱分析的适用条件。研究表明当干扰带宽大于伪码周期的频率的300倍时,伪码非理想随机特性导致的码跟踪精度变化可忽略,反之,则需要基于精细的功率谱模型进行码跟踪精度分析。