Time Series Prediction Method Based on Variant LSTM Recurrent Neural Network

Neural Processing Letters - Time series prediction problems are a difficult type of predictive modeling problem. In this paper, we propose a time series prediction method based on a variant long...     

复杂环境下深大基坑开挖监测与数值模拟分析

以兰州市某复杂环境下深大基坑工程为案例,该基坑开挖深度为17.70~19.10m,主要采用“咬合桩＋预应力锚杆”支护结构,局部采用土钉墙。根据该基坑周围土体、支护结构、邻近建筑监测数据和基坑开挖数值模拟,分析基坑开挖过程中基坑变形性状和基坑开挖对邻近建筑的影响。研究发现：在开挖过程中,基坑支护结构、基坑周围土体和邻近建筑三者变形相互影响;基坑支护结构应避免出现结构性状突变;咬合桩加预应力锚杆的支护结构适用于兰州地区深大基坑项目。最后借助Plaxis3D有限元软件对基坑开挖过程进行数值模拟,模拟结果与监测结果趋势一致,但咬合桩的研究需深入。该深大基坑支护结构对邻近建筑变形起到良好的控制作用,为兰州地区类似基坑项目提供了很好的案例,为复杂环境下深大基坑项目的设计提供参考。     

氯氧镁水泥复合混凝土性能试验研究

基于试验研究与理论分析结果。研究改性剂对氯氧镁水泥复合混凝土材料性能的影响；根据树脂减水剂和苯丙乳液对氯氧镁水泥复合材料强度影响的特点、疏水剂及增强剂对水稳定性影响的特点，阐述针对不同改性目的的改性剂选择要求，以及掺加不同改性刺在环境适应性等方面的差别。     

A novel hybrid data-driven model for multi-input single-output system simulation

Artificial neural network (ANN)-based data-driven model is an effective and robust tool for multi-input single-output (MISO) system simulation task. However, there are several conundrums which deteriorate the performance of the ANN model. These problems include the hard task of topology design, parameter training, and the balance between simulation accuracy and generalization capability. In order to overcome conundrums mentioned above, a novel hybrid data-driven model named KEK was proposed in this paper. The KEK model was developed by coupling the K-means method for input clustering, ensemble back-propagation (BP) ANN for output estimation, and K-nearest neighbor (KNN) method for output error estimation. A novel calibration method was also proposed for the automatic and global calibration of the KEK model. For the purpose of intercomparison of model performance, the ANN model, KNN model, and proposed KEK model were applied for two applications including the Peak benchmark function simulation and the real-world electricity system daily total load forecasting. The testing results indicated that the KEK model outperformed other two models and showed very good simulation accuracy and generalization capability in the MISO system simulation tasks.

     

电位测定振荡反应虚拟仪器的研制与推广

运用离子选择性电极、调理电路、DAQ卡和计算机,构建基于LabVIEW 8.0的电位法测定振荡反应虚拟仪器系统,实现自动采集振荡反应系统电位的变化,实时绘制振荡曲线,存储处理测量数据,自动报告测量结果。虚拟仪器可多路同步,方便快捷地用电位法研究振荡反应,系统操作简便、人机界面友好,避免人工处理数据的繁琐,提高了测量的准确性和重现性。系统测定B-Z振荡反应结果表明,能实时同步绘制出双振荡曲线,其表观活化能测定结果相对误差<0.7%。     

Compressive sensing based sub-mm accuracy UWB positioning systems: A space–time approach

A key challenge to achieve very high positioning accuracy (such as sub-mm accuracy) in Ultra-Wideband (UWB) positioning systems is how to obtain ultra-high resolution UWB echo pulses, which requires ADCs with a prohibitively high sampling rate. The theory of Compressed Sensing (CS) has been applied to UWB systems to acquire UWB pulses below the Nyquist sampling rate. This paper proposes a front-end optimized scheme for the CS-based UWB positioning system. A Space–Time Bayesian Compressed Sensing (STBCS) algorithm is developed for joint signal reconstruction by transferring mutual a priori information, which can dramatically decrease ADC sampling rate and improve noise tolerance. Moreover, the STBCS and time difference of arrival (TDOA) algorithms are integrated in a pipelined mode for fast tracking of the target through an incremental optimization method. Simulation results show the proposed STBCS algorithm can significantly reduce the number of measurements and has better noise tolerance than the traditional BCS, OMP, and multi-task BCS (MBCS) algorithms. The sub-mm accurate CS-based UWB positioning system using the proposed STBCS–TDOA algorithm requires only 15% of the original sampling rate compared with the UWB positioning system using a sequential sampling method.     

改进的网络控制系统稳定性准则

考虑了一类含有网络诱导时滞及数据丢包的网络控制系统稳定性问题。采用了时滞分解的方法,构造了一个新的Lyapunov泛函。在对Lyapunov泛函求导过程中所产生的积分项进行处理时,采用了适当的界定技术并利用凸组合原理,最终得到了一个保守性更小的稳定性准则。最后通过数值示例来验证该准则的有效性。     

LNG管道穿越的隧道工艺安全分析

LNG接收站中的LNG管道穿越隧道因为涉及超低温管道穿越和甲类危险介质,其安全性便显得尤为重要。为此,参考已完成施工的国内第1条(世界第3条)LNG管道穿越的隧道工程,以工艺安全为前提,基于整个LNG接收站的安全设计理念,详细分析了隧道功能分区、安全设置以及操作条件等,以期为深入了解LNG管道穿越此类隧道的安全性提供了理论和数据基础。同时,还总结了隧道建设工程中的各类经验和教训:(1)整个隧道施工过程中,防水最为关键,需要充分考虑设计方案的施工可行性,要么延长工期增加成本、扩大隧道空间增加作业范围,或者寻找其他的替代方案,以做好隧道防水工程;(2)在施工方面,对于LNG隧道工程,应该着重加强施工规范化和标准化;(3)在LNG接收站项目整体规划中的每个阶段、每个上报文件中,都应该充分考虑隧道工程的规划;(4)对于LNG接收站的消防报审等事宜,要把LNG隧道工程作为整体项目不可分割的一部分,整个LNG接收站项目的所有审查均涵盖LNG隧道工程,因而不必单独对LNG隧道工程进行审查。     

面向应急预案领域的Deep Web数据集成研究

应急预案是应急管理的纲领性文件,为应对频发的突发事件,各应急相关部门都建立了自己的应急预案数据库。但这些数据库存在诸多不同程度的异构,阻碍了部门之间的信息共享。针对应急预案异构数据集成,采用本体及本体映射方法解决语义异构的智能识别,以Tomcat+MyEclipse+SQL Server 2005作为开发环境,研究开发物化式Deep Web应急预案异构数据源的集成系统EPIS,创建应急预案中心数据库,为应急预案领域信息共享与应急预案的管理提供基础平台。     

基于阻尼型高斯牛顿法的三维直流电阻率反演

直流电阻率法是浅层水文、工程、环境、考古等与人类社会生活密切相关探测领域的重要手段。地下目标体多表现为三维电性结构,因此,需要对直流电阻率法的三维正反演进行研究和探索。本文利用阻尼型高斯牛顿法的三维直流电阻率反演方法,在迭代的过程中,避免了直接计算偏导数矩阵,而只需计算偏导数矩阵及其转置与任一向量的乘积,同时结合预处理的共轭梯度法求解模型修正量,节省了内存存储量,加快了反演速度。通过对不同模型进行模拟计算,反演结果与实际模型吻合的很好。