“三位一体”数字校园的设计与实现

介绍了集＂日常管理＂、＂水平评估＂、＂决策规划＂三位于一体的数字校园设计方案。通过规范基础数据,采用ESB整合各业务子系统,解决＂信息孤岛＂问题,并为状态数据采集提供便利。利用BI软件进行数据挖据,为管理者进行科学规划和决策提供数据支持。系统采用单点登录,个性化的门户展现满足了各类用户对资源和服务的需求。     

Evaluating Particle Deposition in the Artificial Groundwater Recharge Process by Physical and CT Imaging Experiments

Particle clogging in the artificial groundwater recharge process is one of the main factors influencing the artificial groundwater recharge efficiency, and particle deposition is the microscopic mechanism of the occurrence and development of particle clogging. Particle deposition in porous media changes the pore structure. The computed tomography (CT) scanning technique is a nondestructive testing method and determines the spatial distribution of pores in porous media. This study combines physical and CT scanning experiments to identify the change process of the pore structure in the artificial groundwater recharge process and compares the pore changes during recharge experiments between two columns containing different media. Porous media changes are observed with the CT scanning technique. The fractal theory is applied in the analysis of CT scan images and physical experiment results. The results of this study indicate that particle deposition can be examined by using CT scan images to obtain pore-related parameters, the internal pore structure of porous media determined through CT scan images can be applied in numerical simulation, and a mathematical model for particle deposition calculation in porous media is established. Compared to the physical experiment measurements, the spatial particle deposition information acquired with the CT scanning technique exhibits a higher accuracy and contains much more relevant data. Not only does this research reveal more clearly the particle clogging mechanism which is based on particle deposition, but also characterize, simulate and predict more accurately the development tendency of particle clogging during artificial groundwater recharge.

     

江西省典型水库沉积物碳·氮·磷分布及污染评价

水体富营养化是水库、湖泊水污染问题最为严重的类型之一,为了解江西省水库沉积物的有机物污染水平,笔者测定了江西省15座中型水库沉积物中TP、TN、TOC含量,分析研究其分布特征和来源,并采用有机指数法进行综合评价.成果表明:江西省典型水库沉积物TP、TN总体处于轻度污染状态;在空间分布上,TN、TOC含量总体变幅不大,赣江上游及中游水库沉积物中TP、TN、TOC含量整体较低.TOC/TN比值表明,水生动物和陆地动物是沉积物有机质的主要来源.污染评价成果表明,有机指数IO平均值0.13,总体呈较清洁等级(II级);有机氮WON平均值0.09,总体呈尚清洁等级(III级).     

Study of the hinge thickness deviation for a 316L parallelogram flexure mechanism fabricated via selective laser melting

3D printing offers great potential for developing complex flexure mechanisms. Recently, thickness-correction factors (TCFs) were introduced to correct the thickness and stiffness deviations of powder-based metal 3D printed flexure hinges during design and analysis. However, the reasons for the different TCFs obtained in each study are not clear, resulting in a limited value of these TCFs for future design and fabrication. Herein, the influence of the porous layer of 3D printed flexure hinges on the hinge thickness is investigated. Samples of parallelogram flexure mechanisms (PFMs) were 3D printed using selective laser melting (SLM) and 316L stainless steel powder. A 3D manufacturing error analysis was completed for each PFM sample via 3D scanning, surface roughness measurement and morphological observation. The thickness of the porous layer of the flexure hinge was independent of the designed hinge thickness and remained close to the average powder particle diameter. The effective hinge thickness could be estimated by subtracting twice the value of the porous layer thickness from the designed value. Guidelines based on finite element analysis and stiffness experiments are proposed. The limitations of the presented method for evaluating the effective hinge thickness of flexure hinges 3D printed via SLM are also discussed.

     

基于DSP的程控阵列信号源设计

为了模拟复杂回波信号,设计一种程控阵列信号源;下位机采用数字信号处理芯片TMS320VC5502作为信号源的硬件平台核心,结合DDS技术采用软件编程的方法实现信号源的输出;通过设计通信接口以及定义通行协议,上位机通过操作PXI-6508模块,实现对阵列信号源的程控输出;实验表明,该阵列信号源能同步触发输出96路阵列信号,也能单独输出一路或几路信号,样点率达400kSa/s,输出信号种类有正弦波、方波、三正弦叠加波和调频波等波形。     

CBR系统中一种实例相似度算法的改进

本文对CBR系统中实例相似度的算法进行了改进,在传统实例相似性算法的基础上加入实例属性缺失度因子和实例可复用性因子。因此在实例检索中考虑实例检索结果的精确度和实例的可复用度,进而使检索的精确度提高和修改难度降低,最终提高CBR系统的精确度和实用性。     

Short-term load forecasting using bayesian neural networks learned by Hybrid Monte Carlo algorithm

This paper presents a short term load forecasting model based on Bayesian neural network (shorted as BNN) learned by the Hybrid Monte Carlo (shorted as HMC) algorithm. The weight vector parameter of the Bayesian neural network is a multi-dimensional random variable. In learning process, the Bayesian neural network is considered as a special Hamiltonian dynamical system, and the weights vector as the system position variable. The HMC algorithm is used to learn the weight vector parameter with respect to Normal prior distribution and Cauchy prior distribution, respectively. The Bayesian neural networks learned by Laplace algorithm and HMC algorithm and the artificial neural network (ANN) learned by the BP algorithm were used to forecast the hourly load of 25 days of April (Spring), August (Summer), October (Autumn) and January (Winter), respectively. The roots mean squared error (RMSE) and the mean absolute percent errors (MAPE) were used to measured the forecasting performance. The experimental result shows that the BNNs learned by HMC algorithm have far better performance than the BNN learned by Laplace algorithm and the neural network learned BP algorithm and the BNN learned by HMC has powerful generalizing capability, it can welly solve the overfitting problem.     

Robust H ∞ control of uncertain nonlinear switched systems using constructive method

This paper focuses on the problem of robust H _?? control of nonlinear switched systems with parameter uncertainty via the multiple Lyapunov functions (MLFs) approach. The uncertain parameters are assumed to be in a known compact set and are allowed to enter the system nonlinearly. Based on the explicit construction of Lyapunov functions, which avoids solving the Hamilton-Jacobi-Isaacs (HJI) inequalities, sufficient conditions for the solvability of the robust H _?? control problem of cascade nonlinear switched systems are derived under some switching signal. Then, the result is extended to solve the robust H _?? control problem of nonlinear switched systems in strict feedback form. Finally, the effectiveness of the proposed results is illustrated through a simulation example.     

FD—140型高灵敏测氡仪及其应用

FD—140型高灵敏测氡仪用于测量氡的浓度,测氡灵敏度可达15mBq/m~3 min。该仪器可用于普查与勘探铀矿床,也可用于找石油、煤、金、地下水和地震预报以及地质构造调查等方面。     

项目管理在IT企业中的推广与应用

现阶段传统的管理模式还是一些中小型IT企业的主要管理方式。这种方式导致很多中小型IT企业发展的新旧项目成功率都很小。所以,在当前情况下,要大大加强项目管理的涉及度,使之进入中小IT企业。从而,提高中小企业的核心竞争力。那么什么IT企业,何为项目管理,项目管理在IT企业中的推广应用,以及二者之间的相互关系就是我们研究的重要课题。