无线网络雷击信号快速采集方法研究与仿真

在雷击信号准确采集的研究中,无线网络受到雷击后,会导致信号突变,突变的周期很短.传统的信号采集方法采用提高采集频率的方法对这种瞬时信号进行采集,存在较大漏检风险.为提高采集精度,提出采用小波模糊网络算法的无线网络雷击信号快速采集方法.针对无线传感网络采集到的所有信号进行滤波处理,提取信号特征,并针对信号特征进行微分变换,能够得到滤波处理结果.将上述滤波处理结果输入到小波模糊网络模型中,获取雷击信号特征向量和对应的检测误差,针对检测误差进行补偿,实现无线网络信号更新,模型的输出结果是无线网络雷击信号.实验结果表明,利用改进算法进行无线网络雷击信号检测,能够对雷击信号频率进行准确的分析,提高采集的准确性.     

基于飞参数据的发动机碰摩故障检测模型仿真

在飞行实时状态监控过程中,强震动环境下的发动机碰摩故障检测的准确性,关系到飞行的安全.在强震动环境下,发动机转静容易发生碰摩故障,多个碰摩故障往往是同时发生的,但是,故障的振动信号之间不存在之间关联.碰摩故障特征彼此独立,故障特征数据之间缺少可直接建立的关联.传统的故障挖掘方法在发动机转静碰摩故障检测的过程中,只能 根据振动信号对这种故障进行检测,振动信号本身存在很多干扰,也很难包括所有的碰摩故障特征,导致故障检测不准确.为解决上述问题,提出采用改进关联规则挖掘的强震动环境下的发动机碰摩故障检测方法.针对飞机发动机碰摩数据进行关联聚类处理,获取样本空间的分类矩阵,并对发动机碰摩数据进行更新.根据更新结果,计算发动机碰摩数据关联概率值,得到概率决策,针对飞行器碰摩数据进行关联规则挖掘,实现发动机碰摩数据故障优化检测.实验结果表明,利用改进关联规则算法进行强震动环境下的发动机转静碰摩故障检测,极大的缩短了检测时间,降低了漏检率,提高了检测精确度.     

基于负熵的人员脚步震动信号检测识别算法

提出一种基于震动信号的人员脚步检测识别算法,该算法根据信息论中的负熵概念,采用高阶累积量的负熵近似计算方法.仿真与实测结果证明,与一般的模式识别算法相比,该算法具有三个重要的优点,包括环境适应性强、识别准确率高和运算量小.这些优点使得该算法更适用于能量受限、随机自组的无线传感器网络,能够在野外环境下准确、简单的检测识别人员脚步震动信号.     

基于T-S 模糊模型的一类非线性网络控制系统故障检测

针对同时存在网络时延和数据包丢失的网络环境,研究了一类非线性网络控制系统的鲁棒故障检测问 题．基于不确定T-S 模糊模型描述的非线性网络控制系统模型,完成了网络环境下鲁棒故障检测观测器的设计,使 得残差信号对故障敏感而对外部扰动具有鲁棒性．构造Lyapunov-Krasovskii 函数,并引入一个积分不等式,给出了 使得观测器误差动态系统渐近稳定的充分条件．采用线性矩阵不等式技术将鲁棒故障检测问题转化为具有线性矩阵 不等式约束的凸优化问题求解．仿真算例验证了上述方法应用于此类系统的故障检测的有效性．     

大型炼钢炉炉温异常检测方法研究

在炼钢炉内高温高压环境下,异常温度信号往往瞬间形成,在炉内气浪、异常压力鼓动等外部干扰下,温度异常信号会迅速发生非正常衰减,甚至与其它异常信号发生混淆,造成温度测量不准.传统的炉内温度异常检测方法在信号发生不可控衰减或混淆的情况下,信号分离和识别的过程存在较大困难,在外部干扰下,对温度信号的单独识别、提取效果不佳,温度检测存在较大弊端.提出一种采用约束模糊聚类算法的大型炼钢炉炉温异常信号检测方法.根据傅里叶变换方法对信号采集设备采集到的信号进行隔离处理,克服由于信号混淆带来的困难.根据约束模糊聚类算法,对隔离后的信号进行聚类,使其成为有效的识别特征,完成了异常温度的检测.实验结果表明,利用改进算法进行大型炼钢炉炉温异常检测,能够极大提高异常温度信号检测的准确率.     

强抖动环境下的接口冲突检测模型

在战地通信系统信号检测的研究中,对接口的冲突进行检测,保证设备的正常运行.战地环境多是伴随爆炸、强震动等强抖动环境,强抖动的外部环境对接口的信号形成了较大的外部干扰,使得接口的冲突信号与外部信号形成了纠缠,并且伴随高度的相似性特征.传统的通信接口检测方法无法应对高度相似的信号进行分类,检测的盲目性也随之增加,降低了接口冲突检测准确度.提出利用通信数据量预测的战地强抖动环境下接口冲突检测方法.对通信接口的数据量进行分时段预测,针对当前时间间隔内通信接口冲突的概率进行计算,根据计算结果设定不同的过滤器,最终得到通信接口冲突避免时的最优结果,实现了战地强抖动环境下通信接口冲突检测.试验结果表明,利用改进方法进行战地强抖动环境下的作战单元通信接口冲突检测,能够有效提高检测的准确率.     

杂波环境下网络波动信号采样模型

杂波环境为可对信号产生随机干扰的环境.对上述环境下的网络信号进行采样,可以有效监测网络环境,防范网络入侵和拥堵.由于在杂波环境下的网络信号具有扩展衍射特征,使得正常网络信号存在较大波动性.传统方法进行网络信号采集过程中,在网络信号存在波动的情况下,采样时频重叠调制进行采集,未能纳入杂波先验信息,波动序列的扩展衍射特征形成欠定采样,造成信号采集效果不好.提出基于自适应空间域窗口采集算法的网络波动信号采样模型.将谐波小波核函数和支持向量机理论相结合,获取样本回归模型,得到该模型的约束条件,并对上述回归模型求取最优解,得到网络波动信号采样结果.实验结果表明,利用改进算法进行网络波动信号采样,能够极大的提高采样的准确性和实时性,满足网络波动信号的采集要求.     

计算机视觉对震动环境下螺丝松动的监测仿真

在频繁震动环境下,高精度设备受到无规则振动、冲击以及高温蠕变的影响,导致螺栓结构产生非固定滑动、分离或者脱落.螺栓结构具有复杂的动态性,脱落过程呈现不明显变化,螺丝帽与杆的相对位置变化过程与振动强度、外部环境呈现复杂关系,无法建立有效关联.传统视觉监控方法在振动条件下,获取的螺栓帽和杆的相对像素位置在无法建立关联的情况下,以静态阀值观测为主,存在较大的偏差,无法获取准确的螺栓松动监测结果.提出震动环境下聚类RBF神经网络的视觉螺丝松动监测方法.提取螺丝松动监控计算机视觉图像的特征,并针对上述螺丝帽与脱离的异常距离进行有效的识别.利用傅里叶变换方法建立螺丝松动监控图像特征矩阵,计算特征脱离聚类目标函数,并建立聚类RBF神经网络模型,完成监控.实验结果表明,利用改进算法可以实现计算机视觉对震动环境下螺丝松动监测,可以提高监测的准确性,防止由于螺丝松动造成的损失.     

基于深度学习的网络流量异常识别与检测

针对传统的工控网络流量数据在复杂网络环境下特征维度高,特征处理复杂度高,模型检测效率低等问题,本文使用了一种基于随机森林(random forest, RF)和长短期记忆网络(long short-term memory, LSTM)结合的流量异常识别与检测方法.首先使用随机森林算法计算流量特征的重要度评分,筛选出重要特征,剔除冗余特征,然后使用LSTM进行异常流量的识别与检测.为了评估模型的有效性与优越性,本文使用准确率、精确率、召回率和F1-score进行模型评价,并与传统的机器学习方法 Naive Bayes、QDA、KNN算法进行对比.实验结果表明,在公开数据集CIC-IDS-2017中,异常流量识别的总体准确率达99%.与传统的机器学习算法相比,该方法有效地提高了复杂网络环境下异常检测的准确性和效率,在工业控制网络安全和异常检测方面具有实际应用价值.     

基于PIC18F4680单片机的动态小压力微弱信号检测

采用泥浆压力传输开关信号,是石油钻井探测过程中地面与几千米井下少有的信号传输方式之一,但井下由于压力产生信号变动为毫伏级微小信号,再结合井下高达150℃高温及高震动、强干扰的恶劣环境,这使得有用信号的可靠稳定采集成为难题.针对该问题,以PIC 18 F4680单片机为平台,采用硬件滤波初步排除强干扰信号和软件卡尔曼滤波进一步精确提取有用信号相结合的方式实现井下钻井小压力信号的检测.给出了硬件平台及硬件滤波的详细设计方法,描述了软件卡尔曼滤波应用于压力小信号处理的实现方法,并通过仿真及现场验证证明其可靠性,而且性能超过国外同类技术.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.