入侵防护技术综述

随着Internet高速发展和普及,网络安全问题日益突出。虽然传统的安全防御技术(如防火墙、入侵检测技术等)在某种程度上对防止系统和网络的非法入侵起到了一定的作用,但这些安全技术自身存在先天的缺点,以及对日新月异的网络攻击手法缺乏主动响应。在广大计算机学者的研究和不断探索下,入侵防护系统作为一个新型、动态的安全防护系统诞生了。本文对IPS这种动态安全技术进行了分析和研究。     

内螺纹检测机的设计

以螺母的内螺纹检测为研究对象,针对其传统检测方式以人工为主、费时费力的缺点,提出设计一种内螺纹自动检测机。检测机由一个气动移动平台和检测系统组成,综合考虑功能实现、经济成本、精度误差等因素的影响,提出采用气缸、伺服电机、滚珠丝杠和线性导轨的驱动方式实现工件的精确定位与检测。通过对内螺纹检测机所处的实际生产情况进行研究分析,提出用PLC对整个系统进行控制的方案,以实现对整个流程的精准稳定控制,并详细介绍了控制系统的方案与设计。结果表明:整个设计提高了内螺纹检测的准确性,降低了劳动强度,降低了成本,具有一定的应用价值。     

Design of a randomly distributed sensor network for target detection

This paper explores the design and configuration of a sensor network for target detection. Subject to a budget limit for sensors, the network is required to secure a certain detection probability and to work for a reasonable long time. One novel model of randomly distributed network is presented to fulfill this requirement. A state switching scheme is developed for sensor to save energy. The functional relationships between detection probability and related parameters about sensor, network and target are analyzed. Moreover, a two-level optimization problem is formulated. At the lower level, we optimize the behavior of each sensor subject to its energy constraint and at the upper level, we maximize the lifetime of the network. Equilibrium solution of the two-level optimization problem is obtained by numerical method. An example is presented to illustrate the main results.     

信息熵在数据集分割中的应用研究

针对现行数据集分割方法中的不足，从信息学的角度出发，引用信息熵理论，提出了一种简单可行的数据集分割方法，即选择使数据子集的总体熵较小的分割方式，实验结果证明了这种方法的有效性。     

Process Control in metallurgical plants—From an Xstrata perspective

Some history and modern practice of Process Control in metallurgical operations is reviewed. Clearly the early deliverables from the pioneer days in the 1950s through to the 1970s and early 1980s were under-appreciated. The discipline has since grown into a more visible, sophisticated and accepted practice as a result of the assembly of appropriately recruited and trained individuals and teams, who have successfully negotiated deliverable projects that impact all metallurgical performances beyond early milling processes. The skill set in these individuals and teams essentially includes organisational behaviour in addition to their specialist technical attributes. A strong network to internal and external specialists and experts is essential. Furthermore, instrumentation and control technology has improved immensely. The challenge in the current modern practice is to win support of senior management in operations for the project cost, schedule and deliverables of Process Control. Once gained, this acceptance then amounts to the logistics of project scope and delivery—a track record well-demonstrated by the Xstrata Process Control Group.     

Fast detecting and locating groups of targets in high-resolution SAR images

A new algorithm for detecting and locating groups of targets in high-resolution SAR images is presented. Firstly, a global constant false alarm rate (CFAR) detector is utilized to locate the potential target regions. Then, the size, shape, and contrast features of each region are computed for target discrimination based on voting decision. As targets are often deployed in well-defined groups and all targets within one group have a certain relationship in their positions, it is possible to extract the whole target group and diminish clutter false alarms. The experiment results show that the proposed algorithm significantly reduces the regions revisited by an automatic target recognition (ATR) system, and false alarms can be greatly diminished.     

微波法检测造纸原料热水抽提物

为了更快捷地对造纸原料热水抽提物进行检测，本研究用微波加热方法代替水浴加热。考察了功率和时间两个因素对造纸原料热水抽提率的影响。结果表明，对2g稻草粉末做热水抽提物检测时，采用微波辐射5min，辐射功率用400～600W，可获得与传统恒温水浴180min反应相同的检测效果。经重复实验，微波法大幅提高了检测效率，并且具有一定的可重复性。     

基于图像的圆盘剪侧隙和重合量测量技术

介绍了一种圆盘剪侧隙和重合量的检测方法，针对检测对象的位置及成像特点，采用Canny算子边缘提取法得到检测边缘，具有精度高、算法快的特点，以此开发了相应的检测系统，应用于生产线上，满足了生产检测需求，提高了生产效率。     

Development and validation of a real-time PCR detection method for celery in food

As from 25 November 2005 onwards, a list of ingredients with known allergenic potential has to be labeled according to Directive 2003/89/EC, including celery and products thereof. In order to provide appropriate detection methods a novel real-time polymerase chain reaction (PCR) system for the specific and sensitive detection of DNA from celery (Apium graveolens) was developed and validated. Specificity was confirmed by testing DNA derived from more than 50 food relevant organisms. Sensitivity was demonstrated on the basis of a calibration curve plotting the corresponding Ct-values against DNA amounts ranging from 1 to 1000 copies. Due to the lack of certified reference material the applicability of the method was assessed by analysis of sausages spiked with defined amounts of grounded celery seed. The limit of detection (LOD) examined exemplarily for emulsion-type sausages was 5–10 mg/kg. Analysis of celery-containing commercial products demonstrated the performance potential and limitations of the new real-time PCR system.     

基于SCADA系统给水管网实时检测爆管位置方法的研究

提出了基于SCADA系统城市给水管网实时检测爆管位置的实用方法,通过对管网测压点进行优化布置,利用SCADA系统监测到的管网爆管前后监测点的信息,对管网进行正常和爆管状态下的状态估计,根据整个管网爆管前后节点水压的变化,考虑各节点在管网中的权重,对监测点赋予较大的权重,用模糊相似优先比法快速准确地寻找爆管管段.通过对一城市概化管网的运算验证表明,漏失量在20 L/s以上时,可以达到96%以上的准确率,漏失量为5 L/s的检测准确率也在80%以上.对于DN250的管段,可检测的最小爆管出流量为5 L/s;对于DN900的管段,可检测的最小爆管出流量为40 L/s(＜40 L/s时可检测出漏水区域).