基于灰色AHP的水利工程项目投资风险分析

以水利水电工程项目为研究对象,从自然风险、经济风险、政治风险、技术风险、组织与管理风险、招投标风险六个方面构建了水利水电工程项目投资风险评价体系。针对水利工程风险评价常用方法的缺陷和不足,建立基于灰色AHP的综合评价模型,利用AHP确定评价指标权重,运用灰色系统理论计算综合评价值,得出评价结论。最后,选取水利工程实例进行计算分析,验证了模型的适用性。结果表明:该模型能够为水利水电工程项目投资风险决策和风险管理提供有力的理论依据。     

基于资源分布规律的信息系统风险量化模型

为了实施信息系统的风险度量,首先基于信息流的资源分布规律,参考风险评估要素改进模型,得到具有体系性和完整性的风险分布;在获取风险分布后,基于资源保护角度,考虑安全保护等级,运用层次分析法、多级模糊综合评判、函数级数展开、F-统计量等方法和工具对资源的安全属性所面临的风险进行量化,给出系统的风险量化指标体系,重点考虑风险之间的相关性,构建相关性准则,并得到其计算量为o(Si)。     

基于深度学习的锂离子电池SOC和SOH联合估算

锂离子电池常被作为储能元件以实现电能的存储和转化,然而其荷电状态(state of charge,SOC)和健康状态(state of health,SOH)无法被直接测量。为了实现锂离子电池SOC和SOH联合估算,该文分析SOC和SOH之间的关联性,并提出一种基于深度学习的锂离子电池SOC和SOH联合估算方法。该方法能够基于门控循环单元循环神经网络(recurrent neural network with gated recurrent unit,GRU-RNN)和卷积神经网络(convolutional neural network,CNN),利用锂离子电池电压、电流、温度,实现锂离子电池全使用周期内SOC和SOH的同时估算,而且由于将锂离子电池的SOH估算值考虑到SOC估算中,能够消除锂离子电池老化因素对锂离子电池SOC估算造成的负面影响,从而提升SOC估算精度。两个锂离子电池测试数据集上的实验结果表明,提出的估算方法能够在不同温度和不同工况下实现锂离子电池全使用周期SOC和SOH联合估算,且获得较高的精度。     

水资源系统风险评估研究进展及展望

介绍了水资源系统风险评估指标体系构建和风险评估方法研究进展,着重分析了多种风险评估方法在实践中的优缺点和适用性,总结了传统统计学方法的不足和系统分析方法的局限性及新方法的发展前景,提出了结合数据特征综合利用所需评估方法,同时也为更好地建立水资源风险评估体系奠定了理论基础。     

基于随机水质模型的水功能区COD超标风险分析

由于水环境系统中存在诸多不确定因素,建立在物理简化基础上的确定性水质模型并不能反映水质变化过程的不确定性。为了弥补确定性水质模型的局限性,本文根据随机微分方程理论,假设水质模型中的耗氧系数、沉降系数、复氧系数服从双侧截尾正态分布,建立了考虑随机效应的水质模型。将模型应用于COD超标风险分析,分别计算了不同水文、水质条件下COD浓度的概率分布。结果表明:当三道营来水COD浓度为16、17、18 mg/L时,超标概率为分别在0.3、0.6、0.8左右。     

河南省水生态文明建设试点城市生态系统健康评价

在总结城市生态系统的属性并分析其健康内涵的基础上, 通过频度统计法, 建立评价指标体系。采用海明贴 近度, 建立模糊物元模型, 对河南省第一批水生态文明城市建设试点郑州、 洛阳、 许昌 2000 年- 2013 年间城市生态 系统的健康水平进行评价, 分析影响城市生态系统健康发展的各要素, 结果表明: 郑州、 洛阳和许昌整体的城市生态 系统健康水平呈上升趋势, 但健康改善程度并不显著, 且部分指标有恶化趋势; 相同时期内, 城市生态系统的健康水 平排序由高到低依次为郑州、 洛阳、 许昌, 但其增长速率则为许昌最快、 郑州最慢; 各城市不同要素之间的健康程度 差别较大, 且不同城市各要素之间的协调性较低。因此, 未来应针对健康程度较差的要素重点发展, 提高各要素之 间的协调性, 进一步提高城市生态系统整体的健康水平。     

Behavioural responses to risk on remote outcomes

Computer mediation of communication allows interaction with events remote in space or time. However, the uptake and use of videotechnology requires an understanding of its effects upon willingness to take risks. To understand how responses to remote events are influenced by computer mediation, the present study compared responses to collocated outcomes with those conveyed over a videolink or as pre-recordings. Willingness to risk on an outcome was quantified using wagering behaviour during a simulated game of roulette: measuring preferred outcome format, levels of risk sought, and times required to make decisions. Participants tended to be more confident of winning and preferred the collocated version of roulette. Participants took greater risks with pre-recorded video outcomes and tended to spend more time locating bets. For videolinked outcomes, participants were more cautious, hedging their bets, and taking more time deliberating the odds. Although the amounts wagered did not change, a potential predictability in pre-recordings appears to encourage risk taking, while the reduced presence inherent in real-time videolinks engenders caution.     

Predicting and controlling risks from human exposures to vibration and mechanical shock: flag waving and flag weaving

At work or in leisure activities, many people are exposed to vibration or mechanical shocks associated with risks of injury or disease. This paper identifies information that can be used to decide whether there may be a risk from exposure to hand-transmitted vibration or whole-body vibration and shock, and suggests actions that can control the risks. The complex and time-varying nature of human exposures to vibration and shock, the complexity of the different disorders and uncertainty as to the mechanisms of injury and the factors influencing injury have prevented the definition of dose–response relationships well proven by scientific study. It is necessary to wave a flag indicating when there is a need to control risks from exposure to vibration and shock while scientific enquiry provides understanding needed to weave a better flag. It is concluded that quantifying exposure severity is often neither necessary nor sufficient to either identify risks or implement measures that control the risks.Practitioner Summary: The identification of risks associated with exposure to vibration and mechanical shock cannot, and need not, rely solely on the quantification of exposure severity. Qualitative methods can provide a sufficient indication of the need for control measures, which should not be restricted to reducing standardised measures of exposure severity.     

Computation of optimum reliability acceptance sampling plans in presence of hybrid censoring

The decision regarding acceptance or rejection of a lot of products may be considered through variables acceptance sampling plans based on suitable quality characteristics. A variables sampling plan to determine the acceptability of a lot of products based on the lifetime of the products is called reliability acceptance sampling plan (RASP). This work considers the determination of optimum RASP under cost constraint in the framework of hybrid censoring. Weibull lifetime models are considered for illustrations; however, the proposed methodology can be easily extended to any location-scale family of distributions. The proposed method is based on asymptotic results of the estimators of parameters of lifetime distribution. Hence, a Monte Carlo simulation study is conducted in order to show that the sampling plans meet the specified risks for finite sample size.     

Detection of delamination in laminated composites with limited measurements combining PCA and dynamic QPSO

This paper presents an output only damage diagnostic algorithm based on frequency response functions and the principal components for health monitoring of laminated composite structures. The principal components evaluated from frequency response data, are employed as dynamical invariants to handle the effects of operational/environmental variability on the dynamic response of the structure. Finite element models of a laminated composite beam and plate are used to generate vibration data for healthy and damaged structures. Three numerical examples include a laminated composite beam, cantilever plate made of carbon–epoxy and a laminated composite simply supported plate. Varied levels of delamination of laminated composite plies and matrix cracking at varied locations in the plies are simulated at different spatial locations of the structure. Numerical investigations have been carried out to identify the spatial location of damage using the proposed principal component analysis (PCA) based algorithm. In order to limit the number of sensors on the structure, an optimal sensor placement algorithm based on PCA is employed in the present work and the effectiveness of the proposed algorithm with a limited number of sensors is also investigated. Finally, the inverse problem associated with the detection of delamination and matrix cracking is formulated as an optimization problem and is solved using the newly developed dynamic quantum particle swarm optimization (DQPSO) algorithm. Studies carried out and presented in this paper clearly indicate that the proposed SHM scheme can robustly identify the instant of damage, spatial location, the extent of delamination and matrix cracking even with limited sensor measurements and also with noisy data.