油管锚工艺的应用分析

为降低油井生产过程中的冲程损失,进一步提高开发效果,在理论分析的基础上提出了一种旋转油管锚。介绍了这种工具的结构和工作原理,它具有结构简单、施工方便、性能可靠、经济耐用、作业成功率高等特点。现场应用表明,作业一次成功率达100%。     

A path planning model based on nested regular hexagons using weighted centroid localization

In many wireless sensor network (WSN) applications, the location of a sensor node is crucial for determining where the event or situation of interest occurred. Therefore, localization is one of the critical challenges in WSNs. Mobile anchor node assisted localization (MANAL) is one of the promising solutions for the localization of statically deployed sensors. The main problem in MANAL localization is that the path planning of the mobile anchor (MA) node should be done so that the localization error in the network will be minimal and that all unknown nodes in the network are covered. This paper proposes a new path planning approach called nested hexagons curves (NHexCurves) for MANAL. NHexCurves guarantees that it will receive messages from at least three non-collinear anchors to locate all unknown nodes in the network. The proposed model has compared six different path planning schemes in the literature using weighted centroid localization (WCL). In these comparisons, first of all, localization errors of the models are compared using some statistical concepts. Second, the variation of the localization error according to parameters such as resolution (R) and the standard deviation of noise (σ) is observed. Then, with similar approaches, the standard deviation of errors, localization ratio, scalability performances, and finally, path lengths of the models are examined. The simulation results show that the NHexCurves static path planning model proposed in this study stands out compared to other models with high localization error and localization ratio performance, especially at low resolutions, due to its path design. At the same time, the lowest error values according to σ are obtained with the proposed model among all models considered.     

基于改进单锚节点的无线传感器网络节点定位算法

节点定位是无线传感器关键技术之一,针对固定多锚节点方法定位精度低的缺陷,为了提高无线传感器的定位精度,提出了一种基于改进单锚节点的无线传感器网络节点定位算法(SFOA-SVM)。首先采用单移动锚节点在无线传感器网络中移动,构建无线传感器定位模型的学习样本,然后采用SVM构建节点定位模型,并采用渔夫捕鱼算法模拟渔夫捕鱼行为找到最优SVM参数,最后采用仿真实验测试节点的定位性能。结果表明,相对于其它定位算法,SFOA-SVM提高了无线传感器节点的定位精度,具有一定的实际应用价值。     

DMAP: integrated mobility and service management in mobile IPv6 systems

Mobile IPv6 (MIPv6) is a work in progress IETF standard for enabling mobility in IPv6 networks and is expected to have wide deployment. We investigate an integrated mobility and service management scheme based on MIPv6 with the goal to minimize the overall network signaling cost in MIPv6 systems for serving mobility and service management related operations. Our design extends IETF work-in-progress Hierarchical Mobile IPv6 (HMIPv6) with the notion of dynamic mobility anchor points (DMAPs) for each mobile node (MN) instead of static ones for all MNs. These DMAPs are access routers chosen by individual MNs to act as a regional router to reduce the signaling overhead for intra-regional movements. The DMAP domain size, i.e., the number of subnets covered by a DMAP, is based on the MN’s mobility and service characteristics. Under our DMAP protocol, a MN interacts with its home agent and application servers as in the MIPv6 protocol, but optimally determines when and where to launch a DMAP to minimize the network cost in serving the user’s mobility and service management operations. We demonstrate that our DMAP protocol for integrated mobility and service management yields significantly improved performance over basic MIPv6 and HMIPv6.     

应用三维弹簧系统模型的锚节点部署优化

为使随机部署的三维无线传感器网络中锚节点的分布更加合理,提高未知节点定位精度,针对锚节点部署进行优化。通过构建弹簧系统模型,将锚节点抽象为通过弹簧相连接的点,使部分锚节点在合力作用下进行伸缩运动,达到提高网络性能的目的。当锚节点部署优化完成后,应用近似三角形内点测试( APIT)和DV-HOP( Distance Vector-hop)算法测试优化前后的节点定位精度。仿真结果表明,三维空间下的锚节点经过弹簧系统模型的部署优化后,锚节点网络覆盖率和定位覆盖率均得到了提高,网络平均连通度有所提升,且定位精度显著提高。     

基于无线传感器网络的一种改进Dv-Hop算法

无线传感器网络中的Dv-Hop算法是一种无需测距的节点定位算法,经仿真观察,该算法在信标节点密度较低时节点平均误差较大且稳定性不好.提出了一种改进Dv-Hop算法,即在一个网络区域的边缘设置信标节点.经仿真验证,该算法在和Dv-Hop同等信标节点密度的情况下,在定位精度、节点定位的稳定性以及能源消耗方面都有所改善.     

NSA组网下实现5G与4G用户解耦的方法研究

在当前5G非独立组网（NSA）及4/5G异厂家组网条件下,5G NSA用户出现无法快速驻留5G网络的情况,同时,5G手机图标显示与5G体验速率的关键也取决于此。为提升5G用户感知,本文旨在研究NSA网络场景下,利用锚点移频及SPID功能,实现4G/5G用户的有效解耦以及5G用户的稳定驻留。     

博弈视角下不同直播营销模式的服装电商决策分析北大核心CSCD

为探讨服装电商直播营销模式选择问题,本文使用博弈模型对比服装电商不开通直播、自主开通直播、邀请主播合作直播等不同模式下的预期销量和利润,并分析服装电商开通直播时利润随服装价格弹性系数、传统渠道市场份额变化情况。数值推导和仿真结果表明:1)服装电商开通直播时,利润随着价格弹性系数上升而下降,随传统渠道市场份额增加呈“U”型变化。2)实际转化率较低时,服装电商自主开通直播模式下的利润降低、邀请主播合作开通直播模式下的销量与利润都降低;实际转化率升高,开通直播模式下的销量与利润提高;实际转化率持续升高,邀请主播合作直播模式的销量与利润远高于不开通直播与自主直播模式。     

特高强度大规格钢丝绳吊索制作

介绍特高强度大规格钢丝绳吊索生产控制要点及工艺流程,分析影响索长和吊索强度的因素,通过钢丝绳预张拉处理、恒载索力定尺、二次测量法测量索长,并进行温度修正计算及长度调整等工序,确保索长精度达1/5 000;采用四氯乙烯作为清洗剂清除钢丝表面油污,锚杯预热温度控制在100～110℃,浇铸温度控制在(460±10)℃,浇铸熔融合金的化学成分控制:w(Zn)为(98±0.2)%,w(Cu)为(2±0.2)%,从而保证锚头合金浇灌填充率大于95%,被检测吊索强度不小于钢丝绳最小破断力。     

可重复高压灌浆土层锚杆

论述了可重复高压灌浆锚杆的结构构造以及其独特的灌浆工艺，探讨了该类锚杆的承载能力特性。文中还给出了该类锚杆在不同地层中应用的几个实例。