Modelling airline flight cancellation decisions

In order to predict airline responses to Traffic Management Initiatives (TMIs), and reveal the underlying preference structures that shape these responses, we study US domestic airlines’ cancellation decisions in response to the Federal Aviation Administration (FAA)’s TMIs, in particular, to Ground Delay Programs (GDPs). By observing the actual flight-cancellation choices made by airline dispatchers, the airlines’ cancellation utility functions can be inferred through the use of binary choice models. The model captures how delays to a given flight and potential delay savings to other flights affect flight cancellation decisions. We also find larger, fuller, less frequent, shorter-distance, and spoke-bound flights are less likely to be cancelled, and that there is inter-airline variation in flight cancellation behaviour.     

系统级封装的S频段射频收发模块研制

研制了一种小体积的S频段射频收发系统级封装(SIP)模块,内部集成了基于多种工艺的器件。模块接收通道一次变频,发射通道二次变频,内部集成中频和射频本振信号源。模块采用双腔结构,不同腔体之间通过绝缘子进行垂直互连,大大减小了模块体积,模块体积为40 mm×40 mm×10 mm。模块采用正向设计,其主要指标的测试结果为：接收通道动态范围-100~-40 dBm,输出信号0~2 dBm,噪声系数小于等于2.8 dB,带外抑制大于等于50 dBc;发射通道输出信号大于等于2 dBm,二次、三次谐波抑制大于等于60 dBc,杂波抑制大于等于55 dBc,相位噪声在1 kHz和10 kHz处分别小于等于-82 dBc/Hz和-91 dBc/Hz。实测结果与仿真结果基本一致。     

PCMA自适应自干扰对消算法与仿真

讨论了成对载波多址（PCMA）自适应自干扰对消原理,分析了参数估计误差对自干扰 对消的影响。在频偏误差的影响下对消误差为非平稳过程,传统自适应对消滤波器无法收敛 。为了克服频偏误差的影响,提出了一种自适应可变遗忘因子（VFF） RLS算法,同时,给 出了具有高精度低运算量的模糊函数参数估计算法。仿真证明了VFF-RLS对消算法具有良好 的对消性能和稳健性,且需要的额外功率较低,能满足PCMA系统要求。     

一种3.5 GHz频段双通道射频前端设计

随着5G商用网络的快速建设,国内5G网络测试设备存在大量空缺。为此,设计了一种适用于5G终端模拟器的3.5 GHz频段双通道射频前端。该射频前端结合了ADRV9009芯片,可同时支持双通道收发,具有器件数少、设计复杂度低的特点。实测结果表明,该射频前端性能稳定,接收灵敏度为-85 dBm,噪声系数小于2.6 dB,256QAM调制下发射信号的误差矢量幅度为1.43%,达到了5G终端模拟器的设计要求。     

射频功率放大器告警功能模拟检测方案

射频功放模块是基站系统中的核心部件,出厂前对射频功放模块的功能进行检测意义 重大。设计了一块告警功能测试板,通过观察与射频功放模块相连的测试板上的LED灯,判 断射频功率放大器功能是否正常。实践证明,该方法能模仿射频功率放大器在实际基站系统 中 的工作行为,不仅有效地提高了射频功率放大器的良品率,而且适用于商业化大规模批量生 产。     

论国际货物买卖合同中的合同解除权

《联合国国际货物买卖合同公约》和《国际商事合同通则》是国际贸易法律制度中的重要法律文件,两者皆把合同解除权作为违约救济的一项重要内容,用不少条款加以详细的规定,作为英美法和大陆法两大法系相互结合的产物,其合同解除权制度的具体内容与我们所熟悉的大陆法系或我国《合同法》上的合同解除权有相当的不同.     

一种微带线幅度均衡网络的实现

随着射频系统带宽的增加,如何达到良好的幅频特性成为研究的课题之一。介绍了一种用微带线均衡网络改善雷达发射机射频放大器幅频特性的方法,分析了该均衡网络的工作原理。通过仿真分析,对电路模型进行了改进并在某L频段放大器上对结果进行了验证。由于结构简单易调整,此均衡网络可方便地应用于功放组件内部。     

射频干扰对消技术抗单音干扰性能分析

传统的抗射频阻塞干扰方法会引起有用信号的畸变,同时仅部分抑制了射频阻塞干扰。为了解决这些抗干扰方式存在的不足,提出了一种解决方案射频干扰对消,给出了射频干扰对消抗阻塞干扰的实现方法,并对其抗单音干扰的性能做了计算仿真。结果表明,采用射频干扰对消技术后,在Eb/N0相同的条件下,干信比在10~30dB范围内,对误码率没有影响。     

Termination notice of mobile network operator customers after a tariff switch: An empirical study of postpaid subscribers in Germany

Proactive subscriber churn management strategies of mobile network operators (MNOs) require that steps are taken to keep customers before they hand over a formal notice of termination to their provider. Therefore, several studies have analyzed how MNO customers who gave a termination announcement differ from individuals who did not communicate this message. However, no work has examined such differences among subscribers who recently switched to another tariff of their MNO. Therefore, this paper explores socio-demographic, service consumption and tariff change differences between contract cancellation “announcers” and “non-announcers” in a sample of 1810 postpaid customers who had changed their rate plan not long ago. Cancellation announcers were more likely to be males who decreased their mobile voice consumption after their tariff switch, had already attempted to churn in the past, had moved from an unmetered to a metered rate type, paid higher monthly bill amounts and received no discounts on their current rate plan that was introduced on the market some time ago. Among subscribers who gave a termination notice, early (late) cancellation announcers were more likely to be older (younger) customers with a growing (shrinking) SMS consumption after their tariff switch, had not attempted (had already tried) to leave their current MNO in the past, and were in a rate plan that was (not) recently introduced. The findings contribute to the literature on mobile customer retention and have implications for practitioners and scholars.     

基于远距离无线通信的收费系统设计

介绍了一种基于远距离无线通信的感应式IC卡收费系统的结构、功能、硬件、软件与实现方法.并通过一些技巧,保证了传输数据的完整性与准确性,获得与实时通信同样的视觉效果.最后,强调了实际使用过程中应注意的几个问题.