Results 51 to 60 of about 57,483 (180)

Study on Procurement Optimization for Third-party Reverse Logistics Service Providers of Electronic Products ——Based on Company X [PDF]

open access: yes, 2016
在现代社会,随着科技不断发展,电子产品越来越普及。面对着越来越大的回收压力和售后维修需求,电子产品制造商开始将逆向物流环节外包,这样既可以保持自己的核心竞争力,也能充分发挥各方优势。这就催生了电子产品第三方逆向物流服务行业,他们专门为电子产品品牌商提供逆向物流服务,包括产品的运输、拆卸、检测、维修、报废等服务。这些企业往往经营管理水平较低,而逆向物流存在着极大的不确定性,再加上电子产品本身的一些特点,如产品周期性、种类多等也加剧了这种不确定性,这给企业的管理带来不小挑战 ...
曾倩岚
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Biodiversity‐driven spatial conservation planning to delineate temporally stable regions

open access: yesConservation Biology, EarlyView.
Abstract The accelerating loss of biodiversity underscores the critical need for effective conservation strategies, particularly in the face of climate change and anthropogenic pressures. We devised a conservation planning framework that adopts a temporal stacking approach to species distribution models and landscape connectivity analyses. These models
Mattia Iannella   +5 more
wiley   +1 more source

Stock Forecasting Based on Multi-variables Hybrid Multi-order Fuzzy Time Series and the Genetic Algorithm [PDF]

open access: yes, 2015
中国自1985年发行第一支股票,到股票市场的不断发展和完善,仅用了20多年的时间,这是中国经济改革的辉煌成果。自沪深两个交易所成立以来,我国股票市场高速成长,不断扩大发展,如今在金融市场中占有举足轻重的地位。然而,投资和风险是并存的,股票也不例外。 截至目前,已提出很多股市价格预测的方法,并且随着在股市分析领域中计算机技术应用的扩大和普遍,新的指标分析法也在不断地被提出。 由于股票价格序列符合时间序列的一般特征,而模糊时间序列技术对数据的要求正符合股票数据的特点 ...
万姗红
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Scenarios and strategies for future‐proofing ecosystem management under climatic novelty

open access: yesConservation Biology, EarlyView.
Abstract Climate change is driving unprecedented declines in dominant, habitat‐forming foundation species across marine and terrestrial ecosystems globally. As climatic novelty becomes the norm, ecosystem reassembly will become increasingly common. Predicting and understanding these transitions, and their implications for future ecosystem functioning ...
Lauren T. Toth   +14 more
wiley   +1 more source

基于改进支持向量机的变压器实时热点温度预测方法研究

open access: yesGaoya dianqi, 2018
文中提出了一种基于改进支持向量机的变压器实时热点温度预测方法。该方法以变压器负载电流、环境温度和顶层油温为特征值,将变压器热点温度预警与预测相结合,目的在于实现基于近期历史运行数据的变压器实时热点温度预测。文中研究分析了基于改进网格搜索、遗传算法及粒子群算法的支持向量机在变压器短期热点温度预测中的应用效果,结果表明,3种改进方法均可有效提升预测精度,但基于改进网格搜索算法的支持向量机预测效率最高。最后,以某35 k V油浸式变压器实时热点温度数据为样本集,文中所述方法可有效实现变压器短期热点温度预警预测,
廖才波   +5 more
doaj  

Research on Energy Efficiency Optimization Algorithm for Copper Flash Smelting Process Based on Data-driven [PDF]

open access: yes, 2016
铜闪速熔炼工序具有多变量、非线性、大时滞、强耦合、生产波动大的特点,传统的基于机理模型的优化控制系统很难适应多变的运行条件,预测结果偏差较大,影响最终的控制效果。随着计算机技术的发展,复杂工业过程中积累了大量生产数据,为我们从人工智能的角度进行建模与优化控制提供了数据基础。 本论文以某大型闪速炼铜企业的闪速熔炼生产过程为研究对象。为了实现铜闪速熔炼工序中的节能减耗,本文提出了一种满足三大工艺指标(冰铜品位,冰铜温度,渣中铁硅比)约束的能效优化模型:首先 ...
董云成
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Evaluating synthetic substitutes to reduce illegal harvesting and support species recovery

open access: yesConservation Biology, EarlyView.
Abstract Providing synthetic substitutes is a widely promoted strategy to shift consumer demand away from wildlife products derived from threatened species. Yet, there is little evidence on whether product substitution prevents illegal or unsustainable harvesting and contributes to the recovery of threatened populations.
Aditya Shekhar Malgaonkar   +17 more
wiley   +1 more source

Skewness Forecasting and Skewness Risk Premium [PDF]

open access: yes, 2016
目前大部分关于股票市场预测的现有文献主要是围绕收益率与波动率展开的,然而,大量实证表明,资产价格真实分布并不是传统框架下的正态分布,而呈现出非对称的特点,资产价格的偏度特征同样影响着投资者的行为,所以偏度预测对于投资者的风险管理、投资组合管理等等都有重大意义。在偏度互换尚未推出时,预测偏度可以帮助人们利用期权对冲更好的规避风险,降低对冲成本。本文借鉴Neuberger(2012),借助S&P500期权数据构造具有无偏性以及加和性的已实现偏度,采用一系列的经济变量、股票市场变量 ...
贺晨
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Providing regular and frequent maps of losses and gains of farmland birds based on European monitoring data

open access: yesConservation Biology, EarlyView.
Abstract Knowledge of species distributions is essential for informing policies on nature conservation and restoration. However, updating them on a regular basis and doing so in a harmonized manner at the international level is difficult. The European Bird Census Council integrated national monitoring data covering 5 years to update farmland bird ...
Sergi Herrando   +54 more
wiley   +1 more source

Study of Internal Control and The Style of Management Earnings Forcast:Based on the Semi-mandatory and Semi-voluntary Regulation of China [PDF]

open access: yes, 2015
随着萨班斯法案带来的全球公司治理与内部控制的深刻变革,近年来我国政府因势而为,积极推动内部控制规范建设。无论从理论界还是实务界而言,内部控制与财务信息质量关系均是内部控制相关课题的核心问题之一。目前国内外研究内部控制与财务信息关系的相关文献中,学者们大多把研究重点放在内部控制与历史性财务信息的关系上,鲜少对内部控制与预测性财务信息的关系进行研究分析。作为企业预测性财务信息的重要组成,管理层盈余预测提供的是管理层私有的,面向未来的信息,由于股票的价值是未来现金流量的现值,那么对于投资决策而言 ...
叶颖玫
core  

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