Probabilistic multi-aircraft conflict detection approach for trajectory-based operation

Conflict detection (CD) is one of the key functions used to ensure air transport safety and efficiency. In trajectory-based operation (TBO), aircraft are provided with more flexibility in en route trajectory planning and more responsibility for self-separation. The high flexibility in trajectory planning enables random changes in pilot intent, thus increasing the uncertainty in trajectory prediction and CD. This study proposes a novel probabilistic CD approach for TBO in which the uncertainty of pilot intent is taken into account by quantifying the aircraft reachable domain constrained by the flight plan. First, a probabilistic model for aircraft trajectory prediction is developed using the truncated Brownian bridge method. Based on this model, a novel conflict probability estimation method is developed. Finally, the performance of the proposed probabilistic CD approach is demonstrated through an illustrative air traffic scenario.     

Property Evolution of Sulphoaluminate Grouting Material under Pressure Circulation北大核心CSCD

Water-sealed underground oil tank projects are quite different from traditional underground projects since the water-sealing conditions are very strict and the difficulties caused by the geological specificity, structural specificity and construction specificity are key factors affecting the project. In light of the significant early initial setting time and rapid temperature increase of sulphoaluminate cement-based grouting material for a large domestic water-sealed underground oil tank with pressurized cyclic grouting, a laboratory grouting simulation is conducted. It is found that the properties of the sulphoaluminate cement-based grouting material are quite different under different pressure cycles, the hydration exothermic peak time gets shorter with an increase of circulation time, the compressive strength decreases with an increase of circulation time, and the longer the circulation time the more obvious the de-crease of compressive strength. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

原油管线在线等质量取样系统设计及实现

为了有效解决原油长输管线反复出现的原油途耗异常问题,通过对原油油种、工艺条件和原油输送方式等的分析,设计了等质量流量比例采样系统,由该系统实现原油管线在线自动取样。系统投用后,实现了实时对量,及时发现损耗异常情况,有效控制了原油途耗不稳定的问题。采用等质量流量比例采样模式,较好地解决了多油种、边收边付、多种输送方式以及流量范围宽等不利因素影响计量的问题,具有较好的参考和推广价值。     

埋地管道防腐层破损点检测技术综合应用研究

对防腐层完整性检测尤其是对防腐层破损点的精确定位,及对检出大、中面积破损点开挖修补,是确保土壤跟管道的有效绝缘、提高阴极保护效果的关键。文中分析了常用埋地钢质管道防腐层破损点检测技术特点,结合现场检测实践,综合应用多种技术,能有效检测埋地钢质管道防腐层破损点。根据测量数据可以判断破损点大小以及是否开挖修理,在管道安全运行及检测的经济性之间寻找结合点。     

管道内防腐层补口技术研究进展

管道内衬或内防腐涂层现场施焊时,焊缝两侧的防腐层会由于高温作用而破坏,使环焊缝处不能得到有效的保护,内补口技术也成为影响管道质量的主要瓶颈。文中介绍了国内外主要的内补口技术,如内补口机法、内衬保护套（管）焊接法、不锈钢接头法、机械连接法等,并指出各方法的特点。文中还就内补口技术的质量控制和研究方向等提出了建议。     

一种新型在线长输管道管体检测技术

文中介绍一种以磁应力为原理的检测技术,即磁力断层摄影检测技术.该技术是一种非接触式的被动检测技术,可以检测出长输管道管体各类型缺陷.首先简单阐述了检测原理,其次详细说明了执行一次检测的全流程工作步骤,以及各步骤的工作内容,然后简要介绍了其独特的经验性计算MAOP和剩余寿命的公式,接着以实际试点检测工作为例,说明了该技术的可行性,最后指明了该技术的优缺点.     

高密度电法在某铁路隧道检测中的应用

文章以京包线旗下营隧道工程为例,通过比较高密度电法与地质雷达法酮优劣,提出采用高密度电法进行隧道病害检测,并总结了在应用高密度电法前应进行的准备工作,阐述了高密度电算法在现场检测时的具体操作方法和注意事项。     

基于支持向量机的多传感器船舶火灾探测技术

针对船舶火灾探测误报率高的情况,为提高火灾探测系统的可靠性,提出一种基于支持向量机的多传感器火灾信息融合方法。经过仿真试验证明,通过多传感器探测数据的有效融合,可以大幅提高火灾探测系统的火灾识别率。     

船舶混合动力技术发展趋势分析

通过近年发布的《国际海事组织海运温室气体减排初步战略》等相关减排措施,提出船舶混合动力技术作为优选解决方式。介绍该技术发展背景,阐述其定义、架构及国内外发展应用现状,分析油电混合动力技术、气电混合动力技术的特点,对船舶混合动力技术发展趋势及应用前景进行展望,经调查研究,船舶混合动力推进系统具有操纵性好、效率高及特定工况排放低等特性,减排优势明显。     

一种内河船舶吃水检测系统设计

船舶在通过船闸和升船机等通航设施时因超吃水会导致安全事故,目前常见的船舶吃水检测方法均存在弊端,无法满足检测需求。结合超声波衍射原理,设计一种基于侧扫单波束阵列的吃水检测系统,详细介绍该系统的组成及功能,并在葛洲坝船闸进行安装和测试。结果表明,该系统具有水质适应性强、易于安装、维护方便等优点,能够有效检测船舶动态吃水,测量值与实际核实吃水值的标准差小于0. 086 m,对过闸船舶具有一定的预警作用。