Distributed multi-munition cooperative guidance based on clock synchronization for switching and noisy networks

The Journal of Supercomputing - This paper proposes a novel three-dimensional guidance method based on clock synchronization algorithms, creatively solving the problems of randomized change,...     

基于企业知识图谱构建的实体关联查询系统

针对目前知识图谱查询中节点之间语义关联性不高、查询效率低等问题,提出了一种实体关联的查询方法,然后以此为基础设计并实现了基于知识图谱的企业查询系统。所提查询方法采用四层过滤模型,首先通过路径搜索找到目标节点的公共路径,从而过滤掉关联程度较低的查询节点,得到过滤集合;然后在中间两层分别对过滤集合的属性和关系计算关联度,再基于动态阈值完成图集过滤;最后综合实体关联度和关系关联度得分并排序得到最终的查询结果。基于真实企业数据进行的实验结果表明,与Ness、NeMa等传统图查询方法相对比,所提方法在查询时间上平均降低了28.5%,同时在过滤性能上平均提高了29.6%,可见该方法能高效完成查询和展示与目标相关联实体的任务。     

桌面虚拟化在高校实训机房应用探讨

文章从高校实训机房应用中现存的主要问题出发,介绍了桌面虚拟化技术的基本概念。并在此基础上以VMware View 4桌面虚拟产品为例,介绍了桌面虚拟化环境的搭建,以及在高校实训机房中应用桌面虚拟化的优势。     

Study on the interaction behaviour between lump and sinter under the condition of oxygen blast furnace

This research report describes the influence of the reducing atmosphere of oxygen blast furnace (OBF) and traditional blast furnace (TBF) on the softening and melting behaviour of lump and lump-sinter mixed burdens assessed by using the softening and melting test. The results reveal that in the OBF atmosphere, the softening and melting properties of lump ore is improved compared with that of the TBF, since the development of reduction degree increased the quantity of the iron phase in the burden particle, and decreased the quantity of slag phase with low melting temperature. In addition, the analysis on the microstructure of burden particles revealed that the interaction effect also occurred at the interface between lump and sinter particles in OBF case. Meanwhile, the scanning electron microscope images shows that the interface is still distinguishable when the samples of OBF case reached 60% contraction ratio (1379°C), whereas in the case of TBF, the interface almost disappeared above 40% contraction, and became completely undistinguishable at 60% contraction ratio (1290°C). This illustrates that, under the OBF condition, the starting temperature of interaction is raised, and the effect intensity is weakened.     

Sufficient and necessary conditions for discrete-time nonlinear switched systems with uniform local exponential stability

In this paper, we investigate sufficient and necessary conditions of uniform local exponential stability (ULES) for the discrete-time nonlinear switched system (DTNSS). We start with the definition of T-step common Lyapunov functions (CLFs), which is a relaxation of traditional CLFs. Then, for a time-varying DTNSS, by constructing such a T-step CLF, a necessary and sufficient condition for its ULES is provided. Afterwards, we strengthen it based on a T-step Lipschitz continuous CLF. Especially, when the system is time-invariant, by the smooth approximation theorem, the Lipschitz continuity condition of T-step CLFs can further be replaced by continuous differentiability; and when the system is time-invariant and homogeneous, due to the extension of Weierstrass approximation theorem, T-step continuously differentiable CLFs can even be strengthened to be T-step polynomial CLFs. Furthermore, three illustrative examples are additionally used to explain our main contribution. In the end, an equivalence between time-varying DTNSSs and their corresponding linearisations is discussed.     

Hybrid multistep modeling for calculation of carbon efficiency of iron ore sintering process based on yield prediction

Iron ore sintering is the second most energy-consuming process in steelmaking. The main source of energy for it is the combustion of carbon. To find ways of reducing the energy consumption, it is necessary to predict the carbon efficiency. In this study, the comprehensive carbon ratio (CCR) was taken to be a measure of carbon efficiency, and a hybrid multistep model (HMSM) was built to calculate it. First, the sintering process was analyzed, and the key characteristics of the process parameters were extracted. Next, an HMSM that combines mechanism modeling, data-driven modeling, and integrated modeling was constructed based on the characteristics of the process parameters. The model has three levels: the prediction of key state parameters, yield prediction, and mechanism modeling. First, an integrated fuzzy predictive model predicts the key state parameters based on the evaluation of current operating conditions. Next, predicted values of the state parameters along with key material parameters are used as inputs for a particle swarm optimization-based backpropagation neural network predictive model that predicts the yield. Finally, the predicted yield is fed into the mechanism model, which calculates the CCR. Mechanism and data correlation analyses were used to determine the most appropriate inputs for the three levels. Model verification using actual process data showed that the HMSM accurately predicted the CCR. More specifically, the relative error was in the range (0 %, 2 %] for 91 % of the test samples, and the maximum error was only 5 %. This model lays the groundwork for increasing the carbon efficiency of iron ore sintering.

     

电梯曳引机用铸造锌合金蜗轮的失效分析

利用电子万能试验机、光谱分析仪、光学金相显微镜和扫描电镜等手段,分析了电梯曳引机用锌合金蜗轮的室温及高温力学性能、化学成分、显微组织。结果表明,夹杂物、缩松、气孔等铸造缺陷和偏载过量是导致锌合金蜗轮失效的主要原因。提高采用合理的铸造工艺消除这些铸造缺陷,并提高蜗轮副的加工精度,减小曳引机偏载过量的可能,保障电梯安全、有效地运行。     

市政道路桥梁工程沉降段路基路面施工技术

市政道路桥梁施工质量的好坏,直接关系到道路桥梁交通安全和舒适度.根据大量文献资料,对城市道路桥梁段路面沉降机理中拱形结构、支承结构及桥头结构的变形情况进行分析,并在路面沉降技术的基础上对沉降段进行研究,以期为同行们提供一些参考.     

连续及间歇本体法聚丙烯工艺的比较

对Ｍｏｎｔｅｌｌ公司的液相环管聚丙烯本体聚合工艺和国产间歇液相本体法聚丙烯工艺的工艺流程、操作条件、自动化控制和产品质量、生产成本，以及常见故障等方面进行分析对比，指出两种工艺均有显著经济效益，且前者好于后者，应根据各企业的特点安排生产，并就两种工艺及其操作管理方面的进一步改进提出了建议。     

建立贵阳市高精度测绘基准的研究与思考

讨论了贵阳市高精度测绘基准分阶段实施的主要工作内容和主要技术指标，并对GYCORS、区域似大地水准面精化以及坐标改造等关键技术提出了初步的解决思路和途径。