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Influencing Factors and Prediction of Risk of Returning to Ecological Poverty in Liupan Mountain Region,China
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作者 CUI Yunxia LIU Xiaopeng +2 位作者 JIANG Chunmei TIAN Rujun NIU Qingrui 《Chinese Geographical Science》 SCIE CSCD 2024年第3期420-435,共16页
China has resolved its overall regional poverty in 2020 by attaining moderate societal prosperity.The country has entered a new development stage designed to achieve its second centenary goal.However,ecological fragil... China has resolved its overall regional poverty in 2020 by attaining moderate societal prosperity.The country has entered a new development stage designed to achieve its second centenary goal.However,ecological fragility and risk susceptibility have increased the risk of returning to ecological poverty.In this paper,the Liupan Mountain Region of China was used as a case study,and the counties were used as the scale to reveal the spatiotempora differentiation and influcing factors of the risk of returning to poverty in study area.The indicator data for returning to ecological poverty from 2011-2020 were collected and summarized in three dimensions:ecological,economic and social.The autoregressive integrated moving average model(ARIMA)time series and exponential smoothing method(ES)were used to predict the multidimensional indicators of returning to ecological poverty for 61 counties(districts)in the Liupan Mountain Region for 2021-2030.The back propagation neural network(BPNN)and geographic information system(GIS)were used to generate the spatial distribution and time variation for the index of the risk of returning to ecological poverty(RREP index).The results show that 1)ecological factors were the main factors in the risk of returning to ecological poverty in Liupan Mountain Region.2)The RREP index for the 61 counties(districts)exhibited a downward trend from 2021-2030.The RREP index declined more in medium-and high-risk areas than in low-risk areas.From 2021 to 2025,the RREP index exhibited a slight downward trend.From 2026 to2030,the RREP index was expected to decline faster,especially from 2029-2030.3)Based on the RREP index,it can be roughly divided into three types,namely,the high-risk areas,the medium-risk areas,and the low-risk areas.The natural resource conditions in lowrisk areas of returning to ecological poverty,were better than those in medium-and high-risk areas. 展开更多
关键词 risk of returning to ecological poverty autoregressive integrated moving average model(ARIMA) exponential smoothing model back propagation neural network(BPNN) Liupan Mountain Region China
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Using Return and Risk Model for Choosing Perfect Portfolio Applied Study in Cairo Stock Exchange
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作者 Essam Al Arbed 《American Journal of Operations Research》 2024年第1期32-58,共27页
Modern financial theory, commonly known as portfolio theory, provides an analytical framework for the investment decision to be made under uncertainty. It is a well-established proposition in portfolio theory that whe... Modern financial theory, commonly known as portfolio theory, provides an analytical framework for the investment decision to be made under uncertainty. It is a well-established proposition in portfolio theory that whenever there is an imperfect correlation between returns risk is reduced by maintaining only a portion of wealth in any asset, or by selecting a portfolio according to expected returns and correlations between returns. The major improvement of the portfolio approaches over prior received theory is the incorporation of 1) the riskiness of an asset and 2) the addition from investing in any asset. The theme of this paper is to discuss how to propose a new mathematical model like that provided by Markowitz, which helps in choosing a nearly perfect portfolio and an efficient input/output. Besides applying this model to reality, the researcher uses game theory, stochastic and linear programming to provide the model proposed and then uses this model to select a perfect portfolio in the Cairo Stock Exchange. The results are fruitful and the researcher considers this model a new contribution to previous models. 展开更多
关键词 Game Theory Stochastic and Linear Programming Perfect Portfolio Portfolio Theory returns and risks
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A Monte Carlo-based framework for risk-return analysis in mineral prospectivity mapping 被引量:3
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作者 Ziye Wang Zhen Yin +1 位作者 Jef Caers Renguang Zuo 《Geoscience Frontiers》 SCIE CAS CSCD 2020年第6期2297-2308,共12页
Quantification of a mineral prospectivity mapping(MPM)heavily relies on geological,geophysical and geochemical analysis,which combines various evidence layers into a single map.However,MPM is subject to considerable u... Quantification of a mineral prospectivity mapping(MPM)heavily relies on geological,geophysical and geochemical analysis,which combines various evidence layers into a single map.However,MPM is subject to considerable uncertainty due to lack of understanding of the metallogenesis and limited spatial data samples.In this paper,we provide a framework that addresses how uncertainty in the evidence layers can be quantified and how such uncertainty is propagated to the prediction of mineral potential.More specifically,we use Monte Carlo simulation to jointly quantify uncertainties on all uncertain evidence variables,categorized into geological,geochemical and geophysical.On stochastically simulated sets of the multiple input layers,logistic regression is employed to produce different quantifications of the mineral potential in terms of probability.Uncertainties we address lie in the downscaling of magnetic data to a scale that makes such data comparable with known mineral deposits.Additionally,we deal with the limited spatial sampling of geochemistry that leads to spatial uncertainty.Next,we deal with the conceptual geological uncertainty related to how the spatial extent of the influence of evidential geological features such as faults,granite intrusions and sedimentary formations.Finally,we provide a novel way to interpret the established uncertainty in a risk-return analysis to decide areas with high potential but at the same time low uncertainty on that potential.Our methods are illustrated and compared with traditional deterministic MPM on a real case study of prospecting skarn Fe deposition in southwestern Fujian,China. 展开更多
关键词 Uncertainty quantification GEOSTATISTICS Mineral exploration risk vs return
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Ratio K: a New Way of Metering and Evaluating the Risk and Return of Stock Investment 被引量:1
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作者 朱淑珍 朱静怡 《Journal of Donghua University(English Edition)》 EI CAS 2003年第2期129-136,共8页
Although widely used, both the Markowitz model and VAR (Value at Risk) model have some limitations in evaluating the risk and return of stock investnent.By the analysis of the conceptions of risk and return,together w... Although widely used, both the Markowitz model and VAR (Value at Risk) model have some limitations in evaluating the risk and return of stock investnent.By the analysis of the conceptions of risk and return,together with the three hypotheses of technological analysis, a novelty model of metering and evaluating the risk and return of stock investnent is established.The major indicator of this model , risk-return ratio K, combines the characteristic indicators of risk and return. Regardless of the form of the risk-return probability density functions, this indicator K can always reflect the risk-return performances of the invested stocks clearly and accurately. How to use the model to make optimum investment and how to make portfolio combined with clustering analysis is also explained. 展开更多
关键词 比率 测量方法 风险评估 回归分析 股票投资 VAR模型
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Risk Assessment and Simulation on Storm Flood of the 100-Year Return Period in Hunhe River Basin
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作者 Mingyan Liu Fenghua Sun +3 位作者 Yiling Hou Xiaoyu Zhou Chunyu Zhao Xue Yi 《Journal of Geoscience and Environment Protection》 2018年第7期1-14,共14页
Based on the meteorological and geographic information data, with statistical method and the FloodArea model, the extreme daily rainfall of the 100-year return period in Hunhe River basin was established, through the ... Based on the meteorological and geographic information data, with statistical method and the FloodArea model, the extreme daily rainfall of the 100-year return period in Hunhe River basin was established, through the simulation of rainstorm and flood disaster, characteristics of flood depth in warning spot Cangshi village in the upstream of the river were analysed, and possible effect on community economy was also evaluated. Results showed that, the precipitation of 100-year return period occurred, the flood depth has been below 1.0 meter in the most areas of Hunhe River basin, the depth was between 1.0 meter and 2.5 meters in the part areas of Hunhe River basin, and the flood depth has been exceed 2.5 meters in a small part of Hunhe River basin. After the beginning of precipitation, the flood was concentrated in the upper reaches of the river. With the accumulation of precipitation and the passage of time, the flood pools into midstream and downstream. Precipitation lasted for 24 hours, the warning spot was flooded in the beginning of precipitation. With the accumulation of precipitation, water level of the river increases gradually. The depth of warning spot has passed 1.0 meter at the 07 time of the whole process, and the maximum value of flood depth at warning spot was 1.083 meters that occurred at the 19 time. The flood depth of warning spot decreased gradually after the precipitation stopping, and the depth has been below 0.2 meters, the flood of upstream ended. Up to the end of the upstream flood process, in the whole river, about one million five hundred and sixty thousand people were affected by flooding, and thirty-eight billion and two hundred million RMB of gross domestic product were lost, in addition, dry land and paddy field were affected greatly, but woodland and grassland were less affected. 展开更多
关键词 FloodArea FLOOD Simulation return PERIOD risk Assessment Hunhe River BASIN
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A Study on Equivalence of Return-risk and Risk-return Models for Investment Strategies
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作者 赖民 宋立新 《Northeastern Mathematical Journal》 CSCD 2003年第3期197-200,共4页
1 Introduction It is known that the Capital Asset Pricing Model was first proposed by Markowitz and he was awarded the Nobel Prize
关键词 return risk Lagrange's method KUHN-TUCKER conditions
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Flood risk assessment of check dams in the Wangmaogou watershed on the Loess Plateau of China
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作者 GAO Ze-chao SHI Peng +4 位作者 LI Zhan-bin LI Peng BAI Lu-lu JIA Yi-li CUI Lin-zhou 《Journal of Mountain Science》 SCIE CSCD 2023年第12期3631-3647,共17页
Check dams have been widely used in China’s Loess Plateau region due to their effectiveness in erosion and flood control.However,the safety and stability of the check dam decrease with the operation process,which inc... Check dams have been widely used in China’s Loess Plateau region due to their effectiveness in erosion and flood control.However,the safety and stability of the check dam decrease with the operation process,which increases the probability of dam failure during flood events and threatens local residents’ life and property.Thus,this study simulated flood process of the check dam failure in the Wangmaogou watershed in Yulin City,Shaanxi Province,China,calculated different types of inundation losses based on the flood inundation area within the watershed,and determined the number of key flood protection check dams by classifying the flood risk levels of the check dams.The results showed that 5 dams in the watershed were subject to overtopping during different rainfall return periods,which was related to their flood discharge capacity.Dam failure flood process showed a rapid growth trend followed by slow decrease,and the time of flood peak advanced with increase in the return period.After harmonization of evaluation scales,the magnitude of flood inundation losses can be ranked as:economic losses(212.409 million yuan) > life losses(10.368 million yuan) > ecological losses(6.433 million yuan).The risk value for both individual dams and the whole dam system decreases as the return period increases.The number of key flood protection check dams in the Wangmaogou watershed was 2,3,3,3,4,and 5 for floods with return periods of 10,20,30,50,100,and 200 years,respectively.The results provided a theoretical basis for the safe operation and risk evaluation of check dams in the Loess Plateau Hills watershed. 展开更多
关键词 Check dam return period Flood control risk Dam failure Inundation loss
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恩施州乡村旅游地农户返贫风险评估及其影响因素研究
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作者 乔花芳 许建波 +2 位作者 刘荣 郭子钰 谢双玉 《华中师范大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第1期139-149,共11页
有效预防返贫风险是后脱贫时代脱贫攻坚和乡村振兴战略有效衔接的关键.该研究将风险的概率纳入返贫风险评估体系,从发生概率和破坏程度两方面综合评估其返贫风险,系统反映返贫风险的可能性和破坏性,进而探究其影响因素.研究发现:1)农户... 有效预防返贫风险是后脱贫时代脱贫攻坚和乡村振兴战略有效衔接的关键.该研究将风险的概率纳入返贫风险评估体系,从发生概率和破坏程度两方面综合评估其返贫风险,系统反映返贫风险的可能性和破坏性,进而探究其影响因素.研究发现:1)农户各维度的返贫风险水平从高到低依次为个体风险、家庭风险、社会风险和自然风险,农户受家庭风险和个体风险影响较大,存在明显的内生性、个体化特征.2)依据风险的发生概率和破坏程度,返贫风险可分为“高概率-高破坏”型、“高概率-低破坏”型和“低概率-低破坏”型3种类型,其中,“高概率-高破坏”型风险包括非农就业能力和教育负担,返贫风险指数最高,对农户返贫的威胁最大.3)抚养人数和户主的文化程度等家庭特征是影响返贫风险的主要因素,乡村旅游扶贫开发模式不同导致农户的返贫风险存在显著差异.在返贫防治实践中,应因户施策,重点防治内生性返贫,同时要根据返贫风险发生概率及破坏程度的差异,制定合理的返贫风险预警机制及防治措施. 展开更多
关键词 恩施州 乡村旅游地 返贫风险指数 影响因素
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消费者风险厌恶的运费险分担机制与供应链定价研究
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作者 司凤山 余真 王晶 《武汉理工大学学报(信息与管理工程版)》 CAS 2024年第3期419-425,共7页
考虑消费者的退货行为、风险厌恶态度和运费险价值敏感,建立零售商承担、消费者承担、零售商与消费者共同承担、零售商与制造商共同承担4种不同运费险承担方式的Stackelberg价格博弈模型,研究供应链的定价决策和在线零售商的最优退货运... 考虑消费者的退货行为、风险厌恶态度和运费险价值敏感,建立零售商承担、消费者承担、零售商与消费者共同承担、零售商与制造商共同承担4种不同运费险承担方式的Stackelberg价格博弈模型,研究供应链的定价决策和在线零售商的最优退货运费险策略。研究表明:低退货率和高运费险敏感性有助于提高供应链的整体利润;低退货率时,在线零售商主动为消费者购买运费险优于消费者自行购买;运费险的分担机制不能实现供应链协调。 展开更多
关键词 供应链定价 分担机制 STACKELBERG博弈 退货运费险 风险厌恶
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考虑消费者风险规避的供应链退货运费险与定价策略
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作者 司凤山 余真 王晶 《上海工程技术大学学报》 CAS 2024年第2期223-230,共8页
针对线上买卖双方的退货运费承担纠纷,电商平台引入退货运费险来分摊商品退货风险,但宽松的退货政策又增加了消费者的退货行为。为此,将第三方保险公司引入制造商主导和网络零售商跟随的斯坦克尔伯格博弈中,考虑风险规避型消费者的退货... 针对线上买卖双方的退货运费承担纠纷,电商平台引入退货运费险来分摊商品退货风险,但宽松的退货政策又增加了消费者的退货行为。为此,将第三方保险公司引入制造商主导和网络零售商跟随的斯坦克尔伯格博弈中,考虑风险规避型消费者的退货行为和运费险敏感性,建立多方决策主体共同参与的卖家运费险、买家运费险和运费险共同分担等3种定价退货模型,研究网络零售商的定价决策和运费险策略。结果表明:消费者的风险规避态度有助于降低商品售价和运费险价格,提高市场需求和企业利润;运费险共同分担机制能够有效缓解客户流失;退货率较低时,消费者的运费险偏好有利于供应链总利润的增长。 展开更多
关键词 供应链管理 退货运费险 共同分担 风险规避
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基于深度森林算法的返贫风险预警及防范
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作者 郭文强 谭乔阳 +1 位作者 雷明 马志龙 《长沙大学学报》 2024年第2期1-8,共8页
为巩固拓展脱贫攻坚成果同乡村振兴有效衔接,打好实施乡村振兴战略的基础,文章选取2020年中国乡村振兴综合调查(CRRS)数据为样本,以可持续生计理论为指导构建返贫风险评价指标体系,使用集成学习的多种算法构建返贫风险预警模型。结果表... 为巩固拓展脱贫攻坚成果同乡村振兴有效衔接,打好实施乡村振兴战略的基础,文章选取2020年中国乡村振兴综合调查(CRRS)数据为样本,以可持续生计理论为指导构建返贫风险评价指标体系,使用集成学习的多种算法构建返贫风险预警模型。结果表明:各模型经过参数优化后,深度森林算法识别效果最佳,对返贫风险识别整体准确率为0.98,对构建动态返贫风险预警系统有一定的技术帮助;各地区不同风险等级生计资本存在显著差异性,应因地制宜出台返贫帮扶政策,并为精准帮扶防范返贫提出相应建议。 展开更多
关键词 返贫风险 生计资本 深度森林
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“双碳”背景下气候情绪对四川矿产行业影响路径及风险研究
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作者 刘文文 汤苗苗 赵鹏 《西部经济管理论坛》 2024年第4期67-75,共9页
本文以“双碳”为背景,研究气候风险对四川省矿产上市公司的影响。首先,本文以2014—2022年东方财富网络数据为样本,采用朴素贝叶斯模型构建气候情绪指数。其次,采用多元模型进一步研究气候情绪对四川省上市矿产公司总资产报酬率的影响... 本文以“双碳”为背景,研究气候风险对四川省矿产上市公司的影响。首先,本文以2014—2022年东方财富网络数据为样本,采用朴素贝叶斯模型构建气候情绪指数。其次,采用多元模型进一步研究气候情绪对四川省上市矿产公司总资产报酬率的影响。实证结果表明:本文构建的气候情绪指数与四川矿产上市公司的总资产报酬率存在显著正向关系;气候风险对不同公司类型影响不同,气候情绪对大规模矿产公司的总资产报酬率有显著的促进作用,而对小规模矿产公司总资产报酬率不存在显著影响。因此,为了更好地应对气候变化风险,矿业企业应积极实施低碳战略,主动披露排放信息,提高品牌价值,为长期发展创造新的竞争优势。 展开更多
关键词 双碳 气候风险 气候情绪 朴素贝叶斯 总资产报酬率
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返乡农民工创业失败经历对其创业绩效的影响
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作者 甘宇 罗荟 《华侨大学学报(哲学社会科学版)》 2024年第3期88-101,共14页
探究返乡农民工以往的创业失败经历对当前创业绩效的影响,对促进农户增收,实现乡村振兴具有重要意义。返乡创业失败的农民工再次创业的表现不仅关系到其个人的切身利益,更直接影响当地的创业氛围和乡村振兴战略的顺利推进。基于田野调... 探究返乡农民工以往的创业失败经历对当前创业绩效的影响,对促进农户增收,实现乡村振兴具有重要意义。返乡创业失败的农民工再次创业的表现不仅关系到其个人的切身利益,更直接影响当地的创业氛围和乡村振兴战略的顺利推进。基于田野调查获得的数据,运用二元Logistic模型和中介效应模型方法定量分析创业失败经历对西部地区脱贫县返乡农民工再创业绩效的影响,并探讨其作用机制。结果表明:有先前创业失败经历的样本对象占41.62%,创业失败经历明显负向影响其当前的创业绩效;从作用机制来看,风险应对能力在创业失败经历对再创业绩效的影响过程中发挥着中介作用,创业失败经历抑制了再次创业的返乡农民工的风险应对能力,进而引致他们的创业绩效降低。此外,创业失败经历对生存型创业以及非农创业绩效的抑制更为明显。据此,建议构建多元化的创业学习培训体系,充分发挥榜样的帮扶引领作用,为再创业者提供多元化的信息支持,以阻断先前失败创业经历对返乡农民工再创业的消极影响,增强他们的风险应对能力,促进他们再创业绩效的提高。 展开更多
关键词 返乡农民工 创业失败经历 创业绩效 风险应对能力 创业学习
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乡村振兴背景下脱贫农户返贫风险治理
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作者 陈绍军 张安若 《湖北农业科学》 2024年第4期231-236,共6页
在可行能力理论和可持续生计框架的基础上,构建了“返贫风险识别-返贫风险应对-可行能力发展”的分析框架。在此框架的指导下,基于云南省昭通市M跨县搬迁安置区的实地调研,分析脱贫农户返贫风险治理中存在的问题,并提出优化路径。研究发... 在可行能力理论和可持续生计框架的基础上,构建了“返贫风险识别-返贫风险应对-可行能力发展”的分析框架。在此框架的指导下,基于云南省昭通市M跨县搬迁安置区的实地调研,分析脱贫农户返贫风险治理中存在的问题,并提出优化路径。研究发现,脱贫农户面临多重返贫风险,生计转型困难;安置区产业与就业不匹配,脱贫农户缺乏就近就业机会;基层网格员数据采集困难,动态监测评估指标滞后;脱贫农户内生动力不足,可行能力发展困难。针对这些问题,应建立“以建立防止返贫动态监测机制为基础,以促进脱贫农户增收为根本要求,以推动县域产业发展为主攻方向,以增强脱贫农户可行能力、实现全面发展为核心”的返贫风险治理体系,促进巩固拓展脱贫攻坚成果与乡村振兴的有效衔接。 展开更多
关键词 乡村振兴 返贫风险治理 脱贫农户 可行能力发展
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借贷便利创新工具、资产收益率与商业银行信用风险
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作者 申韬 黄艳香 《金融发展研究》 北大核心 2024年第1期3-12,共10页
本文基于2014—2021年中国203家银行的非平衡面板数据,考察借贷便利创新工具对商业银行信用风险的影响。实证分析发现:借贷便利创新操作会显著增加商业银行信用风险,该结论在考虑内生性问题以及进行一系列稳健性检验后依然成立。异质性... 本文基于2014—2021年中国203家银行的非平衡面板数据,考察借贷便利创新工具对商业银行信用风险的影响。实证分析发现:借贷便利创新操作会显著增加商业银行信用风险,该结论在考虑内生性问题以及进行一系列稳健性检验后依然成立。异质性检验显示,这一政策效应在区域性商业银行、规模较小的商业银行中表现得更为明显。中介效应模型检验表明,借贷便利创新工具通过抑制商业银行资产收益率的渠道增加信用风险。调节效应模型检验结果说明,资本监管力度和银行家乐观度的提高均会减弱借贷便利创新工具对商业银行信用风险的加剧效应。该研究结论对于中央银行适时适量地进行借贷便利操作和商业银行信用风险管理防控具有借鉴意义。 展开更多
关键词 借贷便利创新工具 商业银行信用风险 资产收益率 资本监管 银行家乐观度 新型货币政策工具
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基于县域乡村振兴视角的甘青川藏族聚居县返贫风险研究
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作者 金炳镐 崔慧芳 《西藏大学学报(社会科学版)》 北大核心 2024年第1期144-157,共14页
文章旨在对甘青川藏族聚居县的返贫风险进行研究。样本数据和资料源于对甘青川藏族聚居县精准扶贫及脱贫工作的田野调查。通过调研甘青川三省藏族聚居县的脱贫攻坚工作,从中总结出一些具有地方特色的精准扶贫模式,如迭部县“特色产业模... 文章旨在对甘青川藏族聚居县的返贫风险进行研究。样本数据和资料源于对甘青川藏族聚居县精准扶贫及脱贫工作的田野调查。通过调研甘青川三省藏族聚居县的脱贫攻坚工作,从中总结出一些具有地方特色的精准扶贫模式,如迭部县“特色产业模式”、泽库县“拉格日模式”、若尔盖县“跨地域协作模式”,发现在实践层面,甘青川藏族聚居县存在扶贫项目的立项随意性的问题、部分脱贫技能培训脱离实际的问题、易地搬迁扶贫模式带来的问题。文章通过返贫风险分析,针对巩固拓展脱贫攻坚成果与乡村振兴有效衔接的实现路径提出相关意见建议。 展开更多
关键词 返贫风险 甘青川藏族聚居县 巩固拓展脱贫攻坚成果 乡村振兴
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第三方负责回收的Downside-Risk闭环供应链协调性研究 被引量:13
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作者 史成东 陈菊红 +2 位作者 邢同卫 程均谟 殷秀清 《运筹与管理》 CSCD 北大核心 2011年第4期39-47,57,共10页
以风险中性制造商、第三方物流服务商和具有下行风险特性的销售商组成的闭环供应链系统为背景,证明了在Downside-Risk约束下收益费用共享契约不能使闭环供应链协调。通过将补偿策略附加到该契约,设计了风险共享契约,既能满足下行风险约... 以风险中性制造商、第三方物流服务商和具有下行风险特性的销售商组成的闭环供应链系统为背景,证明了在Downside-Risk约束下收益费用共享契约不能使闭环供应链协调。通过将补偿策略附加到该契约,设计了风险共享契约,既能满足下行风险约束,又保证供应链参与方利润均有增量,实现了Downside-Risk约束下闭环供应链的协调。最后通过应用算例说明了风险共享契约的有效性和可行性。 展开更多
关键词 下行风险 闭环供应链 收益费用共享契约 风险共享契约 补偿策略
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考虑库存风险的服装行业新产品预售策略博弈研究
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作者 孙忠锋 卓晨恕 计国君 《丝绸》 CAS CSCD 北大核心 2024年第2期106-114,共9页
电子商务时代,服装行业线上销售的退货率居高不下。为缓解高退货率连带的库存风险,部分服装企业采用超长预售策略,在相对较长的预售期内次第发货满足顾客订单。在此现实背景下,文章基于报童模型,探讨商家在正常预售和超长预售中的策略选... 电子商务时代,服装行业线上销售的退货率居高不下。为缓解高退货率连带的库存风险,部分服装企业采用超长预售策略,在相对较长的预售期内次第发货满足顾客订单。在此现实背景下,文章基于报童模型,探讨商家在正常预售和超长预售中的策略选择,并求解两种策略的最优定价、产量、利润和可行条件。结果表明:当需求不确定性较大且产品残值较小,预售时长在合理的范围内且顾客更愿意等待时,应选择超长预售策略,反之选择正常预售策略;并且,超长预售策略能够显著降低库存剩余风险。研究结论对服装企业的预售决策和库存管理具有一定的现实参考价值。 展开更多
关键词 预售 库存风险 次第发货 不确定性 报童模型 退货率
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基于病毒传播风险的地铁车厢通风系统优化研究
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作者 伍钒 余超 +2 位作者 徐任泽 崔清民 李恒奎 《铁道科学与工程学报》 EI CAS CSCD 北大核心 2024年第6期2241-2251,共11页
地铁交通系统在提供便利的同时也可能成为病毒传播的温床,优化车厢通风方式是降低病毒传播风险的重要途径。首先,通过数值模拟构建一个典型的集中回风模式地铁车厢模型,并通过实地测量数据验证其准确性。然后,在集中回风模式基础上提出... 地铁交通系统在提供便利的同时也可能成为病毒传播的温床,优化车厢通风方式是降低病毒传播风险的重要途径。首先,通过数值模拟构建一个典型的集中回风模式地铁车厢模型,并通过实地测量数据验证其准确性。然后,在集中回风模式基础上提出了一种分散回风模式,与集中回风模式进行对比分析,探讨2种模式下车厢内流场和飞沫扩散特征。最后,结合感染风险评价模型讨论了乘客的感染风险。研究结果显示:在车厢流场和温度场方面,集中回风模式下车厢内15个测点的气流速度和温度均值分别为(0.27±0.13) m/s和(26.4±1.35)℃,分散回风模式下分别为(0.25±0.08) m/s和(26.2±0.94)℃。在飞沫扩散方面,集中回风模式下飞沫受到集中回风口产生的纵向气流影响,在车厢内扩散的区域相比于分散回风模式下更大,集中回风模式下飞沫扩散的区域是分散回风模式下的1.45倍。在乘客感染风险方面,整体上分散回风模式下站姿和坐姿乘客的感染风险都小于集中回风模式下乘客感染风险,且在飞沫释放后的0~20 s内集中回风模式下站姿乘客感染风险是分散回风模式下的1~2倍。相对于集中回风模式,车厢采用分散回风模式可以提高车厢内速度场和温度场的均匀性,并且可以更快地清除乘客呼吸区的飞沫,降低乘客的感染风险。研究结果可为进一步优化地铁车厢通风系统和保障乘客出行安全提供参考。 展开更多
关键词 地铁车厢 回风模式 飞沫扩散 数值模拟 感染风险
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林区规模性返贫的潜在风险与韧性治理策略
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作者 黄吉迎 宁满秀 +1 位作者 张维泰 张皓乙 《林业经济问题》 北大核心 2024年第1期59-67,共9页
从社会经济、突发环境和主体脆弱3个层面分析林区规模性返贫所面临的潜在风险。基于规模性返贫韧性治理的内涵,从抵御与恢复力、适应与转型力、学习与再造力3个特征维度构建规模性返贫韧性治理“全资本韧性耦合—全要素韧性互动—全过... 从社会经济、突发环境和主体脆弱3个层面分析林区规模性返贫所面临的潜在风险。基于规模性返贫韧性治理的内涵,从抵御与恢复力、适应与转型力、学习与再造力3个特征维度构建规模性返贫韧性治理“全资本韧性耦合—全要素韧性互动—全过程韧性循环”的机制框架。在此基础上,提出构建韧性治理共同体,提升多元主体韧性;建立长效保障机制,提升产业、人才、文化、生态和组织韧性等规模性返贫韧性治理建议。 展开更多
关键词 韧性治理 林区 规模性返贫 潜在风险
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