基于RNN-LSTM的船舶位置预测分析

针对传统马尔科夫模型在长时序跨度条件下,预测船舶的下一位置精度较低且系统复杂度较高的问题,提出了一种基于长短型记忆循环神经网络(Recurrent Neural Networks-Long Short-Term Memory,RNN-LSTM)的船舶位置预测模型。利用DBSCAN聚类算法提取历史轨迹中的目标位置序列作为预测模型的输入,降低预测系统复杂度。引入Word2Vec模型中的Skip-grams算法将目标位置转换成位置向量,提升目标位置的区分度。实验结果表明,适当调整聚类算法参数可有效提升预测精度,所提模型预测准确度也高于传统预测模型。

基于压缩感知和几何滤波的RTI定位算法

免携带设备定位因其不需要目标携带任何穿戴设备就能获取位置信息,在安防和紧急救援等应用场合受到越来越多的关注。免携带设备定位的关键技术就是利用目标引起的射频信号强度进行定位。提出了一种基于压缩感知和几何滤波的免携带设备定位算法。该算法是基于无线层析成像（RTI）的定位算法,使用先验位置估计来构造一个圆形的先验区域,来移除外部链路,减少不可能的位置点,降低算法复杂度;其次将圆形先验区域进行像素的精确划分,将定位问题转化为稀疏信号的重构问题,最后利用压缩感知求解。实验结果表明,该算法减少了计算的复杂度,提高了定位精度,降低了对存储和计算资源的要求。

齐家大岘引水隧洞施工支洞布设方案研究

施工支洞布设方案是决定长距离引水工程施工难度和成本的重要因素。文章以齐家大岘引水隧洞施工支洞为研究对象,结合地形地质及施工条件对比研究了完全利用、调坡后利用、支洞内设衔接旁支洞三种方案的优缺点。确定了支洞内设衔接旁支洞方案为最佳方案,研究结果可为长距离输水隧洞施工支洞选择与布置提供参考。

不同水沙条件下甘肃某引水工程引水闸布置方案研究

以甘肃某引水工程为例,优化了引水工程引水闸方案,研究了不同水沙条件下引水工程建筑物冲淤情况、流速、水边线以及水流流态的变化情况。结果表明:优化方案改善了引水闸水流流态,回流流速及面积明显减小,水流流态比较平稳;墙顶高程和整治段堤顶高程满足泄流要求;闸前泥沙淤积高程较低,满足设计防沙、泄洪和引水要求。可为甘肃引水工程优化设计提供理论参考,具有重要的工程应用意义。

Breast cancer stem-like cells can promote metastasis by activating platelets and down-regulating antitumor activity of natural killer cells

OBJECTIVE:To investigate whether cancer stem cells(CSCs) more efficiently activating platelets and evading immune surveillance than non-CSCs thus promoting metastasis.METHODS:We enriched and identified sphereforming cells(SFCs) and coincubated washed platelets with several platelet activators including collagen,4T1 and SFCs.Platelet-coating tumor cells,platelet activation and TGF-β1 release were analyzed.Then natural kell cells(NK) were incubated with supernatants of different activated platelet samples what we called sample release(SR).The degranulation assay and NKG2 D expression on NK cells were conducted by flow cytometry.Finally tissue factor(TF) expression of SFCs or 4T1 were evaluated by western blot.RESULTS:Breast cancer cell line 4T1 could form spheres in serum-free medium at low adherence.Sphere-forming cells expressed high levels of the CD24-/lowCD44 + stem cell phenotype.Both sphere-forming cells or 4T1 were coated with abundant platelets while sphere-forming cells induced significantly higher expression of platelet activating receptor CD62 p than 4T1 did(P < 0.01).And sphere-forming cells induced platelets to produce more TGF-β1 than 4T1 did(P < 0.01).Furthermore,sample releases induced by sphere-forming cells caused more vigorous inhibition of NK cells antitumor reactivity(P < 0.05) and reduced NKG2 D expression(P < 0.01).The final results showed that sphere-forming cells expressed higher levels of TF than 4T1(P < 0.05).CONCLUSION:Our findings indicate that CSCs could efficiently activate platelets,induce platelets to secrete more TGF-β1,decrease NKG2 D expression and inhibit antitumor activity of NK cell,compared with 4T1.And higher levels of TF expression of CSCs may account for this correlation of CSCs and platelets.