ELA-120/6型电子束焊机高压电源隐患分析及对策

分析了EAL-120/6型电子束焊机高压电源存在的安全隐患,提出了消除隐患的两种措施:一是不改动油箱电路,从操作规程上加以解决;二是给高压电容加装并联放电电阻支路.给出一种改进实例.经试验证明,第二种消除隐患措施更为有效,停机10 s后,高压电缆间无"火花"出现.     

Incorporating Intra‐Query Term Dependencies in an Aspect Query Language Model

Query language modeling based on relevance feedback has been widely applied to improve the effectiveness of information retrieval. However, intra‐query term dependencies (i.e., the dependencies between different query terms and term combinations) have not yet been sufficiently addressed in the existing approaches. This article aims to investigate this issue within a comprehensive framework, namely the Aspect Query Language Model (AM). We propose to extend the AM with a hidden Markov model (HMM) structure to incorporate the intra‐query term dependencies and learn the structure of a novel aspect HMM (AHMM) for query language modeling. In the proposed AHMM, the combinations of query terms are viewed as latent variables representing query aspects. They further form an ergodic HMM, where the dependencies between latent variables (nodes) are modeled as the transitional probabilities. The segmented chunks from the feedback documents are considered as observables of the HMM. Then the AHMM structure is optimized by the HMM, which can estimate the prior of the latent variables and the probability distribution of the observed chunks. Our extensive experiments on three large‐scale text retrieval conference (TREC) collections have shown that our method not only significantly outperforms a number of strong baselines in terms of both effectiveness and robustness but also achieves better results than the AM and another state‐of‐the‐art approach, namely the latent concept expansion model. © 2014 Wiley Periodicals, Inc.     

中医诊断古文的词性标注与特征重组

中医诊断古文存在大量单音词,使用通用切词技术处理,结果是单个的分词结果,不能构成一个完整的诊断词汇。对此,设计一个基于键值对模型的中医诊断词性标记集,提出基于词汇联系的隐马尔可夫模型（HMM ）,进行词性标注,结合词法分析,采用移进归约算法进行特征重组,生成中医诊断词汇。实验结果表明,改进的 HMM 的词性标注准确率在训练集和测试集中分别提高了2?58％和1?02％,特征重组结果是完整独立的诊断词汇,方便中医人员进行诊断分析,适合构成向量空间模型的特征。     

大数据环境下移动对象自适应轨迹预测模型

已有的轨迹预测算法针对移动对象运动模式,使用数学模型进行交通流模拟,难以对路网中的移动对象进行准确的描述.为了解决这一问题,提出基于隐马尔可夫模型(hidden Markov model,简称HMM)的自适应轨迹预测模型SATP(self-adaptive trajectory prediction model based on HMM),对大数据环境下移动对象海量轨迹利用基于密度的聚类方法进行位置密度分区和高效分段处理,减少HMM的状态数量.根据输入轨迹自动选取参数组合,避免HMM模型中隐状态不连续、状态停留等问题.实验结果表明,SATP模型在实验中表现出较高的预测准确性,并维持较低的时间开销.针对速度随机改变的移动对象,其平均预测准确率为84.1%;相同情况下,平均高出朴素预测算法46.7%.     

分子标记多位点排序的并行计算

为了对一组连锁的分子标记位点获得正确的排序进而构建生物遗传连锁图谱,提出了并行算法PMMASLH,针对F2作图群体,通过基于消息传递接口并行最大最小蚂蚁系统求解连锁的多个分子标记位点排序,使用隐马尔可夫模型计算一列有序标记位点所获得的极大似然值作为排序的目标函数。计算机模拟结果表明,该算法执行效率高、计算稳定,排序的功效优于著名的连锁作图软件Mapmaker。     

数据挖掘技术在网络安全检测中的应用价值

在网络运行中,经常出现由于恶意网络攻击行为、网络配置失误等引起的异常网络流量,这些偏离正常范围的异常流量会直接对整个网络服务质量造成影响,导致网络瘫痪,因此在网络运行时,进行安全检测并及时提供预警信息对保障网络安全正常运行十分重要。本文在介绍数据额挖掘技术的基础上,对利用挖掘领域中的隐马尔科夫模型建立基于异常检测的入侵检测系统进行了分析,并通过仿真实验验证了这一系统的可靠性,论述了数据挖掘技术在网络安全检测中的应用价值。     

云计算安全隐患及其对策分析

从构成云计算的三个主要方面深入分析可能存在的安全隐患,着重对云计算的SaaS、PaaS、IaaS三大服务模式存在风险的可能展开研究分析,同时对加强云计算安全的措施提出了建议。     

It's the Thought that Counts: The Mediating Effects of Information Processing in Virtual Team Decision Making

Abstract

Previous research shows that although collaboration technology can improve the exchange of information during team decision making, one of the challenges is that this better discussion often does not lead to better decisions. In this paper, we investigate the impact of individual information processing on team decision making. We investigated the effects of two types of collaboration technology when participants were either the member of a team majority or a team minority. There was little impact due to the majority/minority, but the use of collaboration technology that required users to categorize the comments they received from others resulted in increased information processing, which in turn led to better decisions and more satisfied participants.     

以可靠性为中心的水轮机组检修模式研究

以可靠性为中心(RCM)的维修模式是在一般视情维修的基础上,吸收以可靠性为中心的维修分析法的优点,充分考虑到经济性、可靠性原则,并与先进的设备诊断技术相结合的一种维修模式。介绍了水轮机组RCM维修模式,重点分析了根据经济性和可靠性原则分别确定隐患检测间隔期,以及用威布尔分布拟合机组零部件故障间隔时间分布的表示及参数的获得。     

基于雷达散射特征的堤防隐患诊断技术研究

结合堤防隐患的雷达散射特性,研究了不同堤防隐患在雷达波散射效应下的特征表现,分析 了空洞、渗透、松散体、滑坡、裂缝、漏水等堤防隐患的雷达图谱。研究表明:堤防隐患的成像效果 依赖于雷达设备的技术指标、测量参数和操作方法等因素,隐患图像解释的准确性依赖于图像处理技 术。针对不同堤防隐患和设备物理参数,研究雷达波的散射特征,有助于更高精度地解析图像信息, 是解决雷达波干扰多、衰减快、特征弱等问题的有效途径。结合雷达波的形态、波长、振幅、相位等 特征信息,在对散射信号进行解释时采用二维时频分析的瞬态谱,并运用小波分析、Hilbert变换、Z 变换等方法对图像进行去噪、增强、滤波处理,可对堤身探测范围内的隐患性状、分布、形态信息进 行有效诊断。