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基于关联系数的电子超市网站结构优化模型及算法复杂性分析
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作者 王有为 汪定伟 《小型微型计算机系统》 CSCD 北大核心 2004年第4期522-525,共4页
将网站结构抽象为无权有向图 .为方便顾客选购某种商品后以较短的路径访问相关商品网页 ,建立了一种网站结构优化的数学模型 ,并采用禁忌搜索算法 (TS)对问题进行求解 .算法复杂度分析的结果显示 ,在 TS进行临域搜索时本文提出的启发式... 将网站结构抽象为无权有向图 .为方便顾客选购某种商品后以较短的路径访问相关商品网页 ,建立了一种网站结构优化的数学模型 ,并采用禁忌搜索算法 (TS)对问题进行求解 .算法复杂度分析的结果显示 ,在 TS进行临域搜索时本文提出的启发式算法优于布尔矩阵乘法以及重复调用广度优先算法 . 展开更多
关键词 商品相关性 网站结构优化 禁忌搜索 算法复杂度分析 电子超市
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电子超市易用性评估及链接结构优化模型
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作者 王有为 汪定伟 《系统仿真学报》 CAS CSCD 2003年第2期190-192,共3页
用无权有向图来描述网站结构。提出以网站是否方便顾客访问相关商品网页为标准的网站评估方法,建立了一种网站结构优化的数学模型,并采用禁忌搜索算法(TS)对问题进行求解。通过一个随机网站结构的例子,说明更新算法比布尔矩阵乘法以及... 用无权有向图来描述网站结构。提出以网站是否方便顾客访问相关商品网页为标准的网站评估方法,建立了一种网站结构优化的数学模型,并采用禁忌搜索算法(TS)对问题进行求解。通过一个随机网站结构的例子,说明更新算法比布尔矩阵乘法以及重复调用广度优先算法进行TS领域搜索具有更高的效率。实例研究表明所述方法可以帮助网站设计者通过增减少量的链接得到更加方便顾客使用的网站结构。 展开更多
关键词 电子超市 易用性评估 链接结构 优化模型 电子商务 商品相关性 网站结构优化 禁忌搜索
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Effects of Genotype and Planting Density on Agronomic Traits and Storage Root of Sweetpotato
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作者 闫会 李强 +5 位作者 张允刚 后猛 唐维 王欣 刘亚菊 马代夫 《Agricultural Science & Technology》 CAS 2017年第2期238-243,246,共7页
The effects ol different genotypes and planting densities on main agronomic traits, storage root traits and yield were studied with 6 high-quality sweetpotato varieties as study objects by 2-factor completely random d... The effects ol different genotypes and planting densities on main agronomic traits, storage root traits and yield were studied with 6 high-quality sweetpotato varieties as study objects by 2-factor completely random design. The results showed that there were significant differences in stem diameter, length of the longest vine and top/root (T/R) between different genotypes, T/R differed significantly under dif- ferent planting densities, and number of basal branches decreased with planting density increasing. Genotype and genotype x density showed significant or very sig- nificant effects on fresh root yield per plant, dry matter content and fresh root yield per hectare, fresh root yield per plant gradually decreased with planting density in- creasing, while fresh root yield per hectare increased with planting density increas- ing. Numbers of storage roots in different sizes of the 6 sweetpotato cultivars all exhibited an order of number of large-sized storage roots〈number of medium-sized storage roots〈small-sized storage root; and there were very significant differences in ratio of large-sized storage roots between different genotypes. The number of large- sized storage roots, ratio of large-sized storage roots and number of commercial storage roots deceased with planting density increasing, while there were no signifi- cant differences in number of medium-sized storage roots, number of small-sized storage roots, ratio of medium-sized storage roots and ratio of small-sized storage roots between different densities. Correlation analysis showed that there was signifi- cant positive correlation between number of basal branches and fresh root yield per plant; dry matter content in storage roots was in significant positive correlation with stem diameter, and in significant negative correlation with length of the longest vine; fresh root yield per hectare was in significant positive correlation with fresh root yield per plant, and in very significant negative correlation with dry matter content; and ratio of large-sized storage roots was in very significant positive correlation with number of large-sized storage root and fresh root yield per plant, and in very sig- nificant negative correlation with ratio of medium-sized storage roots and ratio of small-sized storage roots. This experiment showed that under the planting density of 7.5×104 plants/hm2, the 6 sweetpotato cultivars all reached the highest numbers of commercial storage roots and fresh root yields per hectare. 展开更多
关键词 SWEETPOTATO GENOTYPE Planting density Agronomic trait Storage root Commercial root Correlation
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能源金融研究回顾与前沿方向探索 被引量:26
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作者 龚旭 姬强 林伯强 《系统工程理论与实践》 EI CSSCI CSCD 北大核心 2021年第12期3349-3365,共17页
随着能源商品金融化的不断加深,能源金融成为一个新兴的前沿领域,开始受到国内外学者的广泛关注.本文首次较全面地梳理了能源金融理论的发展脉络,从能源价格驱动因素、能源市场建模与预测、能源资产定价与套期保值、能源-商品-金融市场... 随着能源商品金融化的不断加深,能源金融成为一个新兴的前沿领域,开始受到国内外学者的广泛关注.本文首次较全面地梳理了能源金融理论的发展脉络,从能源价格驱动因素、能源市场建模与预测、能源资产定价与套期保值、能源-商品-金融市场相关性、能源行业投融资以及能源公司金融六个方面描述了能源金融的研究进展,凝练出各方向的研究热点.进一步,本文提出了大数据能源金融、人工智能+能源金融以及能源金融与能源安全三个前沿研究方向.通过本文的梳理,对当前的能源金融理论与实证研究进行了系统的阐述,能够为推动能源金融理论的发展提供借鉴和指导意义. 展开更多
关键词 能源金融 资产定价 能源-商品-金融市场相关性 能源行业投融资 能源公司金融
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