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51.
Power system transient stability assessment based on the multiple paralleled convolutional neural network and gated recurrent unit 下载免费PDF全文
In order to accurately evaluate power system stability in a timely manner after faults, and further improve the feature extraction ability of the model, this paper presents an improved transient stability assessment (TSA) method of CNN?+?GRU. This comprises a convolutional neural network (CNN) and gated recurrent unit (GRU). CNN has the feature extraction capability for a micro short-term time sequence, while GRU can extract characteristics contained in a macro long-term time sequence. The two are integrated to comprehensively extract the high-order features that are contained in a transient process. To overcome the difficulty of sample misclassification, a multiple parallel (MP) CNN?+?GRU, with multiple CNN?+?GRU connected in parallel, is created. Additionally, an improved focal loss (FL) function which can implement self-adaptive adjustment according to the neural network training is introduced to guide model training. Finally, the proposed methods are verified on the IEEE 39 and 145-bus systems. The simulation results indicate that the proposed methods have better TSA performance than other existing methods. 相似文献
52.
根据CD级柴油机的模拟实验与台架试验的基础数据,用人工神经网络的反向传播(BP)方法,对两者的关系进行了研究,给出了人工神经网络的学习速率为0.2,动量因子为0.9,对人工神经网络的拓扑结构也进行了研究,得到了合适的5-7-2拓扑结构及各节点间的权重系数。探讨了用模拟实验数据预测台架试验结果的可能性,通过检验,证明了用人工神经网络方法建立的模型能准确预报柴油机油的台架试验结果。 相似文献
53.
基于认证协议的Web单点登录优化设计 总被引:2,自引:0,他引:2
针对Kerberos认证协议Web环境中进行单点登录存在的安全隐患,基于Schnorr协议的挑战/响应方式,结合Secure Cookies、HttpSession解决Web环境下HTTP协议的无状态性及服务器间的安全会话。实验结果表明,该方案性能稳健,响应速度快,防攻击力强,具有良好的实用价值和应用前景。 相似文献
54.
55.
蒋小莺 《数字社区&智能家居》2010,(4):778-780
SAML是由OASIS提出的基于XML规范用于网络应用间用户身份及授权等安全信息描述和交换的一个规范。基于SAML规范,可以在已建立信任关系的不同服务实体间进行认证、授权等信息的传递。该文主要针对以Identity Pmvider(IdP)发起模式实现Web SSO中对SAML的应用进行一定的研究。 相似文献
56.
郭玲 《计算机与数字工程》2010,38(7):84-88
针对企业多套应用系统用户认证相对独立、用户必须同时使用多个账户重复登录的问题,根据企业应用环境特点设计了一种单点登录(SSO)体系,该设计基于SAML技术构建统一认证平台,建立了用户帐号映射关系,对现有系统进行客户化改造,封装成认证中心(IDP)和服务提供者(SP),通过集成的认证代理实现认证服务,实现了SSO和现有系统的良好结合。 相似文献
57.
Chi-man Vong Pak-kin Wong Weng-fai Ip 《Engineering Applications of Artificial Intelligence》2011,24(7):1281-1294
Whenever there is any fault in an automotive engine ignition system or changes of an engine condition, an automotive mechanic can conventionally perform an analysis on the ignition pattern of the engine to examine symptoms, based on specific domain knowledge (domain features of an ignition pattern). In this paper, case-based reasoning (CBR) approach is presented to help solve human diagnosis problem using not only the domain features but also the extracted features of signals captured using a computer-linked automotive scope meter. CBR expert system has the advantage that it provides user with multiple possible diagnoses, instead of a single most probable diagnosis provided by traditional network-based classifiers such as multi-layer perceptions (MLP) and support vector machines (SVM). In addition, CBR overcomes the problem of incremental and decremental knowledge update as required by both MLP and SVM. Although CBR is effective, its application for high dimensional domains is inefficient because every instance in a case library must be compared during reasoning. To overcome this inefficiency, a combination of preprocessing methods, such as wavelet packet transforms (WPT), kernel principal component analysis (KPCA) and kernel K-means (KKM) is proposed. Considering the ignition signals captured by a scope meter are very similar, WPT is used for feature extraction so that the ignition signals can be compared with the extracted features. However, there exist many redundant points in the extracted features, which may degrade the diagnosis performance. Therefore, KPCA is employed to perform a dimension reduction. In addition, the number of cases in a case library can be controlled through clustering; KKM is adopted for this purpose. In this paper, several diagnosis methods are also used for comparison including MLP, SVM and CBR. Experimental results showed that CBR using WPT and KKM generated the highest accuracy and fitted better the requirements of the expert system. 相似文献
58.
The specific problems associated with the work on board within the merchant fleet are well known and have over the years been a topic of discussion. The work conditions in the engine room (ER) are demanding due to, e.g. the thermal climate, noise and awkward working postures. The work in the engine control room (ECR) has over recent years undergone major changes, mainly due to the introduction of computers on board. In order to capture the impact these changes had implied, and also to investigate how the work situation has developed, a total of 20 engine officers and engine ratings were interviewed. The interviews were semi-structured and Grounded Theory was used for the data analysis. The aim of the present study was to describe how the engine crew perceive their work situation and working environment on board. Further, the aim was to identify areas for improvements which the engine crew consider especially important for a safe and effective work environment. The result of the study shows that the design of the ECR and ER is crucial for how different tasks are performed. Design which does not support operational procedures and how tasks are performed risk inducing inappropriate behaviour as the crew members’ are compelled to find alternative ways to perform their tasks in order to get the job done. These types of behaviour can induce an increased risk of exposure to hazardous substances and the engine crew members becoming injured. 相似文献
59.
从目前来看,学校网络机房的管理中管理者更多关注的是技术上的维护和保障工作,缺乏维修理念、缺乏对故障信息、维修信息的系统分析、缺乏对维修的效一费分析以及有效度的分析,因此,网络机房的维修工作存在着盲目性,缺乏计划性和目标性。所以应加强网络机房的科学化管理,加强对机房故障信息的统计分析,预防并减少故障,改善网络机房设备的技术状态;加强可靠性为主的维修理念,提高机房维修的有效度,确保机器本身的正常运转,延长使用寿命,更保障教学的顺利进行:本文通过对网络机房故障信息和维修信息的记录分析,得出对机房故障、维修方面有实效性的管理措施和对策。 相似文献
60.
小聪明 《数字社区&智能家居》2008,(4):119-120
农业专家系统是一项在信息技术中结合农业特点发展起来的高新技术。它对于提高广大农业人员的科技文化素质,提升农业科技自主创新能力,实现农业生产的跨越发展具有特别重要的作用。高等农业院校和广大农村又是农业专家和农业知识高度密集的地方,更应该使农业专家系统拥有广阔的用武之地。 相似文献