基于灰关联法发动机故障诊断的研究

应用灰关联理论对发动机的故障进行诊断。灰关联分析属非函数型的序列模式,能有效处理杂散数据。通过建立工程机械发动机系统故障树,运用灰关联分析对关联度进行计算及排序,给出各种故障模式发生的可能性排序,从而为处理故障、控制故障的发生以及改进系统的可靠性提供理论依据。     

宁波市天一广场盆栽大树移植技术探讨

本文以天一广场盆栽大树成功移植经验为基础,详细论述了城市绿化建设中特殊条件下大树移植发方法,以期对类似园林工程施工有所帮助。     

回归分析在土地估价中的应用

回归分析是一种统计学方法，在地价分析与测算中得到广泛应用。本文从统计学的角度阐明了回归分析的原理，并介绍了如何建立回归方程解决土地估价中出现的有关问题。     

货币政策影响居民储蓄行为的有效性分析

本选取了我国1994年至2000年的统计数据，通过统计学的方法来分析货币政策在分流我国居民的巨额储蓄时是否有效，并进一步分析了对货币政策效果产生干扰的制度因素。     

我国股改中权证的价格泡沫及影响因素

本文针对我国股改中的百慕大权证提出了新的“模拟树-市场情绪”定价模型。该模型的实证研究结果表明中国权证市场价格存在严重高估;加入市场情绪指标后,通过建立多元回归模型得到了对于实际价格的显著的拟合结果,有力地解释了超出权证理论价格的实际价格所包含的情绪因素。本文最后对权证价格高估的原因及权证未来的走势进行了分析。     

探究“新零销售”模式下影响销售量的相关因素

在新零销售模式的推动下,客户越来越倾向于消费个性化的商品。为了精准预测客户的消费需求,论文以单款单色产品为研究对象,通过建立多元回归分析的数学模型,来探究影响商品销售量的相关因素。经过分析发现,除了一些定性因素外,定量因素对销售量也产生了一定的影响,其中实际花费总金额、实际销售单价、库存数等定量因素对销售量的影响较大,且各个变量之间具有相关性,所以电商平台应特别关注这三个变量的影响。     

Prediction of the Indian summer monsoon using a stacked autoencoder and ensemble regression model

The study of climatic variables that govern the Indian summer monsoon has been widely explored. In this work, we use a non-linear deep learning-based feature reduction scheme for the discovery of skilful predictors for monsoon rainfall with climatic variables from various regions of the globe. We use a stacked autoencoder network along with two advanced machine learning techniques to forecast the Indian summer monsoon. We show that the predictors such as the sea surface temperature and zonal wind can predict the Indian summer monsoon one month ahead, whereas the sea level pressure can predict ten months before the season. Further, we also show that the predictors derived from a combination of climatic variables can outperform the predictors derived from an individual variable. The stacked autoencoder model with combined predictors of sea surface temperature and sea level pressure can predict the monsoon (June-September) two months ahead with a 2.8% error. The accuracy of the identified predictors is found to be superior to the state-of-the-art predictions of the Indian monsoon.     

昭通横江流域年径流预测

针对昭通横江由南到北贯穿昭通全境,水资源量丰富,但南北差异大,南部少、北部多的特点,根据流域内水文站实测年径流、大气环流指数、海温指数及其他指数等资料系列,采用多元回归分析法拟合1981—2010年径流,建立了预测模型,验证、预测分析了2011—2016年径流量。结果表明:干流控制站预测精度高于干流上段及支流代表站,水利工程建设等人类活动影响是导致出现这样结果的主要原因;多元回归分析在横江流域径流预测中具有一定的适应性,但因指标的差异及相关参数可获取性的差异,预测结果存在区域间、等级间的差别。     

Mangrove forests as a nature-based solution for coastal flood protection: Biophysical and ecological considerations

Nature-based coastal protection is increasingly recognised as a potentially sustainable and cost-effective solution to reduce coastal flood risk. It uses coastal ecosystems such as mangrove forests to create resilient designs for coastal flood protection. However, to use mangroves effectively as a nature-based measure for flood risk reduction, we must understand the biophysical processes that govern risk reduction capacity through mangrove ecosystem size and structure. In this perspective, we evaluate the current state of knowledge on local physical drivers and ecological processes that determine mangrove functioning as part of a nature-based flood defence. We show that the forest properties that comprise coastal flood protection are well-known, but models cannot yet pinpoint how spatial heterogeneity of the forest structure affects the capacity for wave or surge attenuation. Overall, there is relatively good understanding of the ecological processes that drive forest structure and size, but there is a lack of knowledge on how daily bed-level dynamics link to long-term biogeomorphic forest dynamics, and on the role of combined stressors influencing forest retreat. Integrating simulation models of forest structure under changing physical (e.g. due to sea-level change) and ecological drivers with hydrodynamic attenuation models will allow for better projections of long-term natural coastal protection.     

应对长江口咸潮入侵的临界流量经验模型研究

1994年以来,长江口咸潮入侵严重威胁当地供水安全,随着长江上游水库群陆续建成,有关部门提出了通过上游水库群压咸调度保障长江口地区供水安全的方案。为明确压咸调度的目标流量(即临界流量),基于统计分析的方法,采用多元回归分析和主成分分析方法,选取实测站点数据建立了盐度-潮差-入海流量的相关关系统计模型,研究了咸潮发生的机理;通过模型分析多次咸潮入侵数据,确定临界流量为一个变化值,潮差290～335 cm下的临界流量在9 390～21 633 m³/s之间。研究表明,当长江口咸潮入侵时,单独依靠长江上游水库调度压咸所需的流量大,响应时间长,压咸效果不明显。因此,实际压咸调度应通过流域整体调度与本地蓄淡避咸水库共同作用应对咸潮入侵。