软件工程数据挖掘研究

本文通过对软件工程数据挖掘的相关概念进行全面的研究,并且对软件开发的流程进行分析,结合笔者多年的软件开发数据挖掘实践经验,总结出现阶段我国软件工程数据挖掘面临的挑战.提出科学合理的软件工程数据挖掘基本流程与任务,为我国软件工程数据挖掘研究提供科学的依据.     

Self-adaptive interval type-2 neural fuzzy network control for PMLSM drives

This paper proposes a self-adaptive interval type-2 neural fuzzy network (SAIT2NFN) control system for the high-precision motion control of permanent magnet linear synchronous motor (PMLSM) drives. The antecedent parts in the SAIT2NFN use interval type-2 fuzzy sets to handle uncertainties in PMLSM drives, including payload variation, external disturbance, and sense noise. The SAIT2NFN is firstly trained to model the inverse dynamics of PMLSM through concurrent structure and parameter learning. The fuzzy rules in the SAIT2NFN can be generated automatically by using online clustering algorithm to obtain a suitable-sized network structure, and a back propagation is proposed to adjust all network parameters. Then, a robust SAIT2NFN inverse control system that consists of the SAIT2NFN and an error-feedback controller is proposed to control the PMLSM drive in a changing environment. Moreover, the Kalman filtering algorithm with a dead zone is derived using Lyapunov stability theorem for online fine-tuning all network parameters to guarantee the convergence of the SAIT2NFN. Experimental results show that the proposed SAIT2NFN control system achieves the best tracking performance in comparison with type-1 NFN control systems.     

Sensitivity analysis and optimization of vehicle–bridge systems based on combined PEM–PIM strategy

This paper presents a new optimization method for coupled vehicle–bridge systems subjected to uneven road surface excitation. The vehicle system is simplified as a multiple rigid-body model and the single-span bridge is modeled as a simply supported Bernoulli–Euler beam. The pseudo-excitation method transforms the random surface roughness into the superposition of a series of deterministic pseudo-harmonic excitations, which enables convenient and accurate computation of first and second order sensitivity information. The precise integration method is used to compute the vertical random vibrations for both the vehicle and the bridge. The sensitivities are used to find the optimal solution, with vehicle ride comfort taken as the objective function. Optimization efficiency and computational accuracy are demonstrated numerically.     

高岭土的活化及其地质聚合物的性能研究

研究了4种高岭土在不同煅烧条件下的活化及其地质聚合物的抗压强度和H4 交换容量的变化趋势.试验结果表明:产地相同的高岭土在800℃煅烧6 h后,所合成的地质聚合物的抗压强度和NH4 交换容量达到最大值;产地不同的高蛉土经相同条件煅烧后,所合成的地质聚合物的抗压强度和NH4 交换容量差异很大,这与高岭土的化学成分没有相关性,而与煅烧高岭土在碱溶液中的硅铝溶出率有相关性.     

地球影像在铁路用地管理中的应用

地球影像在经济文化建设中的重要性日益突出。可以采用的方式是使用Google Earth提供的API,结合应用实际,显示、编辑用地的详细信息。该文详细介绍了基于Google Earth API开发的铁路用地管理软件,特别对重要API的使用、权限的管理进行了详细的描述。     

Unintentionally produced dioxin-like polychlorinated biphenyls during cooking

The formation and distribution of dioxin-like polychlorinated biphenyls (dl-PCBs) during cooking was investigated. Concentrations of dl-PCBs in liquid residues, cooked beef, and oil fumes generated during heating were determined by isotope dilution HRGC/HRMS. Although the levels of dl-PCBs in well-done beef were lower compared with those of raw beef, relatively high concentrations of dl-PCBs were detected in the oil fumes produced during heating. This suggests that dl-PCBs in raw beef may have volatilized into the oil fumes during the cooking process. Sucralose and chloropropanols contained in raw materials may have resulted in increased dl-PCB concentrations and the level of toxic equivalents (TEQ) in the oil fumes produced under high temperature during cooking. Concentrations of dl-PCBs did not vary greatly in cooked beef, except when higher levels of chloropropanols were presented in the uncooked raw materials. Results indicate that sucralose and chloropropanols may promote the formation of dl-PCBs during the cooking process. The newly produced dl-PCBs from raw beef cooking were mainly present in oil fumes, which gave rise to high levels of TEQ in oil fumes.     

基于GPS_GPRS车辆监控终端设计与实现

车辆定位监控系统作为高新技术中智能交通系统的一个重要分支,90年代以后得到了很大的发展。定位监控系统的发展主要受到通信网络和地理信息系统发展情况的制约。文中介绍了一种基于GPS（全球定位系统）和GPRS（通用分组无线业务）的车辆定位监控系统,给出了车载终端部分的硬件、软件的设计以及实际测试结果分析。由于采用GPRS网络进行数据传榆,使得此车辆监控系统具有实时性好、实用性好和扩展性好等优点。     

Method for Overflow Attack Defense of SDN Network Flow Table Based on Stochastic Differential Equation

In order to avoid the overflow problem of network flow table caused by hackers attacking the network in the process of using the network, a method for overflow attack defense of SDN network flow table based on stochastic differential equation is proposed. In this method, the stochastic differential equation is first proposed, and the drift coefficient and diffusion coefficient of the equation are expanded and adjusted by Taylor. By using the limit theorem, the spillover attack of SDN network is weakly converged to an approximate two-dimensional Markov diffusion process, and the improved stochastic differential equation is obtained. Then, according to the stochastic nature of SDN network attack, the stochastic differential equation is transformed into an amplitude equation, which is based on the amplitude. The equation establishes a SDN attack detection scheme based on flow table statistics, which detects the spillover attacks of SDN network flow tables. Finally, according to the test results, it is proposed to use other switches instead of network flow table overflow switches to control the data upload rate, thus reducing the possibility of network crash and meeting the attack defense requirements of flow table overflow. The simulation results show that the proposed method has better detection performance and shorter running time, and can provide help for network security related work.

     

数字粮库的展望

以计算机技术、多媒体技术和大规模存储技术为基础,以宽带专用网络为纽带,运用粮情测控技术、全球定位系统、地理信息系统、虚拟现实等技术,对国内所有粮库及其存粮情况进行多分辨率、多尺度、多时空和多种类的数字描述。即利用信息技术手段把有关粮库的所有信息在网络上进行数字化虚拟实现,以便于粮库的监测和管理,同时也是为国家粮食管理部门提供一个粮食政策的决策支持平台。