Data-driven preventive maintenance for a heterogeneous machine portfolio

We describe a data-driven approach to optimize periodic maintenance policies for a heterogeneous portfolio with different machine profiles. When insufficient data are available per profile to assess failure intensities and costs accurately, we pool the data of all machine profiles and evaluate the effect of (observable) machine characteristics by calibrating appropriate statistical models. This reduces maintenance costs compared to a stratified approach that splits the data into subsets per profile and a uniform approach that treats all profiles the same.     

Inverse conductivity Problem with Internal Data

This paper concerns the reconstruction of a scalar coefficient of a second-order elliptic equation in divergence form posed on a bounded domain from internal data. This problem finds applications in multi-wave imaging, greedy methods to approximate parameter-dependent elliptic problems, and image treatment with partial differential equations. We first show that the inverse problem for smooth coefficients can be rewritten as a linear transport equation. Assuming that the coefficient is known near the boundary, we study the well-posedness of associated transport equation as well as its numerical resolution using discontinuous Galerkin method. We propose a regularized transport equation that allow us to derive rigorous convergence rates of the numerical method in terms of the order of the polynomial approximation as well as the regularization parameter. We finally provide numerical examples for the inversion assuming a lower regularity of the coefficient, and using synthetic data.     

土地监察移动数据库技术及其应用

近年来,基于移动数据库的移动GIS技术发展呈加速趋势,并在越来越多领域的应用中取得成功.在土地监察工作中采用移动GIS手段,有利于实现实时、快速执行土地违法勘察、执法动态监察等工作,为建立完善的土地管理长效机制提供技术支持,保障人民群众的利益和社会的稳定.本文先介绍移动数据库的原理和架构,然后结合土地监察实际需求,重点探讨移动数据库在土地监察中需要解决的数据同步、数据复制与缓存和数据安全存储等关键技术问题.     

面向UPMIS的控规数据批量转换方法及实现

控规数据向ArcGIS平台数据转换并入库是城市规划管理信息系统（UPMIS）建设的一项基础性工作.针对分析控规数据转换为ArcGIS平台数据存在的问题,提出了一种高效的控规数据向ArcGIS平台数据批量转换的方法,并结合ArcGIS VBA和Python脚本开发工具,实现了上述方法.测试实验表明,该方法自动化程度高、实现简单、处理效率高.     

基于可编程器件的Rijndael加密算法优化实现

本文针对无线传感器网络传感器节点处理能力弱、携带能量低的特点,提出基于Rijndael算法优化的数据加密技术.通过对Rijndael加密算法的数据存储、列混合以及轮变换等特点的分析,提出对于加密算法的优化建议,采用可编程逻辑器件对优化后的加密算法进行设计和实现,并进行加密验证,同时对优化后加密算法的数据处理速率、算法功耗、逻辑资源占用情况进行评估.由实验结果可知,优化后的Rijndael加密算法相比优化之前有很大的突破,能够适用于无线传感器网络的数据加密.     

ULTRAHIGH DATA DENSITY STORAGE WITH SCANNING TUNNELING MICROSCOPY

Ultrahigh density data storage devices made by scanning probe techniques based on various recording media and their corresponding recording mechanisms, have attracted much attention recently, since they ensure a high data density in a non-volatile, erasable form in some kinds of ways. It is of particular interest to employ organic polymers with novel functional properties within a single molecule (or a single molecular complex) for fabricating electronic devices on a single molecular scale. Here, it is reported that a new process for ultrahigh density and erasable data storage, namely, molecular bistability on an organic charge transfer complex of 3-nitrobenzal malononitrile and 1,4-phenylenediamine (NBMN-pDA) switched by a scanning tunneling microscope (STM). Data density exceeds 10¹³ bits/cm² with a writing time per bit of ～1μs. Current-voltage (I/V) measurements before and after the voltage pulse from the STM tip, together with optical absorption spectroscopy and macroscopic four-probe I/V measurements demonstrate that the writing mechanism is conductance transition in the organic complex. This mechanism offers an attractive combination of ultrahigh data density coupled with high speed. The ultimate bit density achievable appears to be limited only by the size of the organic complex, which is less than 1nm in our case, corresponding to 10¹⁴ bits/cm². We believe that provided the lifetime can be improved, molecular bistability may represent a practical route for ultrahigh density data storage devices.     

电阻温度系数的微机测定系统

本文介绍一种电阻温度系数微机测定实验的系统。     

Python在热敏电阻测量实验数据处理中的应用

Python语言因为语法简洁、功能全面、开发的程序具有可移植性而拥有十分广阔的应用市场.Python在诸多方面都有应用,如科学计算、应用开发以及计算机科学教育等.本文就热敏电阻测量实验的数据处理问题进行了分析,同时也进行了系统的图形化界面设计以及用Python语言编写相关的脚本来实现了实验数据的数据库存储功能.     

Systematics on fission fragment mass distribution of neutron induced 235U fission

Based on the neutron induced fission fragment mass distribution data up to neutron energy 20 MeV measured with the double kinetic energy method (KEM) and the radio active method (RAM), the systematics of fission fragment mass distribution was investigated by using 5 Gaussian model and the systematics parameters were obtained by fitting the experimental data. With the systematics, the yields of any mass A and at any energy in the region from 0 to 20 MeV of neutron energy can be calculated. The calculated results could well reproduce the experimental data measured with KEM, but show some systematical deviation from the data measured by RAM, which reflects some systematical deviations between the two kinds of measured data.The error of systematics yield was calculated in an exact error transformation way, including from the error of the experimental yield data to the error of the discrete parameters, then to the systematics parameters,and at last to the yield calculated with systematics.     

Ab initio multi-reference configuration interaction of the low-lying states of the AsP molecule

Nine low-lying electronic states of the AsP molecule, including Σ , Ⅱ, and △ symmetries with singlet, triplet, and quintet spin multiplicities, are studied using multi-reference configuration interaction method.The potential energy curves and the spectroscopic constants of these nine states are determined, and compared with the experimental observed data as well as other theoretical works available at present.Three quintet states are reported for the first time.Furthermore, the analytical potential energy functions of these states are fitted using Murrell-Sorbie function and least square fitting method.