新一代天气雷达运行能力评估研究

研究我国新一代天气雷达运行能力的评估方法,建立天气雷达运行能力评估指标体系,合理地选取现有的新一代天气雷达数据资料,定量地评估各型号、分时段的雷达业务可用性、可靠性、可维修性及其变化趋势.编制能反映雷达运行能力的各类评估图表,并以图表的分析为依据,提出今后发展建议.     

类规模对面向对象度量与易维护性关联关系潜在混和效果元分析

用在设计阶段可以收集到的3个规模度量分析类规模对面向对象度量与易维护性之间关联关系的混和效果.为得到尽可能通用的结论,在127个C＋＋系统和113个Java系统上分析类规模的混和效果.首先,对每个面向对象度量,在单个系统上计算代表由类规模造成的关联扭曲的间接效果和它的方差.然后,利用统计的元分析方法计算这些系统上的平均间接效果并判断它是否显著地区别于零.实验结果表明,不论使用哪个类规模度量进行分析,类规模对面向对象度量与易维护性之间关联关系的混和效果通常是存在的.因此,验证面向对象度量与易维护性之间关系的实验研究应将类规模视为一个混和变量.     

粮食测温系统结构及技术应用对故障率的影响

随着粮库的改扩建,粮食储存高度集中的发展,粮食自动化测温在粮库建设和管理中得到广泛应用,然而目前粮库所使用的测温系统不同程度地存在着故障率高、可靠性低、可维护性差等诸多问题。本文根据对系统结构的分析和维修经验,介绍系统结构及所采用的技术对粮食测温系统故障率的影响。     

从三种机型APU的对比讨论其未来的发展趋势

APU作为飞机的辅助动力装置,能够为飞机提供电源、气源和液压源,有着不可替代的作用。随着科学技术的发展,飞机的维修性与安全可靠性得到了重视,这对APU提出了更高的要求。结构简单,重量轻,易于维修,成本低,将是APU未来的发展趋势。     

城域网的MPLS VPN技术应用与性能分析

随着企业信息化进程的加快,传统VPN组网技术暴露出诸多问题,如网络安全技术复杂、难于扩展和维护等。在实践中,利用ISP城域网组建MPLS VPN,具有安全性高、可扩展性和可维护性好等特点,并能够解决私网IP地址在公网上的重叠问题。     

船舶及船用设备的可维修性

通过分析船舶及船用设备的可维修性概念、要求及影响因素,指出提高船舶及船用设备的可维修性,应在船舶及设备的设计与建造阶段,充分考虑部件的互换性、维修的可达性、简易方便性等;在管理方面重视人与环境因素对可维修性的影响.最后,引入在线维修理论,对大型部件进行不拆卸现场维修,以缩短维修时间,保证船舶的安全营运生产.     

Performance of LIDAR- and radar-based turbulence intensity measurement in comparison with anemometer-based turbulence intensity estimation based on aircraft data for a typical case of terrain-induced turbulence in association with a typhoon

The Hong Kong Observatory (HKO) provides low-level turbulence alerting service for the Hong Kong International Airport (HKIA) through the windshear and turbulence warning system (WTWS). In the WTWS, turbulence intensities along the flight paths of the airport are estimated based upon correlation equations established between the surface anemometer data and the turbulence data from research aircraft before the opening of the airport. The research aircraft data are not available on day-to-day basis. The remote sensing meteorological instruments, such as the Doppler light detection and ranging (LIDAR) and radar, may be used to provide direct measurements of turbulence intensities over the runway corridors. The performances of LIDAR- and radar-based turbulence intensity data are studied in this paper based on actual turbulence intensity measurements made on 423 commercial jets for a typical case of terrain-induced turbulence in association with a typhoon. It turns out that, with the tuning of the relative operating characteristic (ROC) curve between hit rate and false alarm rate, the LIDAR-based turbulence intensity measurement performs better than the anemometer-based estimation of WTWS for turbulence intensity at moderate level or above. On the other hand, the radar-based measurement does not perform as well when compared with WTWS. By combining LIDAR- and radar-based measurements, the performance is slightly better than WTWS, mainly as a result of contribution from LIDAR-based measurement. As a result, the LIDAR-based turbulence intensity measurement could be used to replace anemometer-based estimate for non-rainy weather conditions. Further enhancements of radar-based turbulence intensity measurement in rain would be necessary.