考虑用户活跃度和项目流行度的基于项目最近邻的协同过滤算法

项目相关性度量是基于项目最近邻的协同过滤算法的关键。已有的项目相关性度量方法在数据集稀疏或推荐低流行度产品时会面临较大挑战,因此提出一种考虑用户活跃度和项目流行度的基于项目最近邻的协同过滤算法。该算法在度量两个项目的相关性时,若有记录只对两个项目之一有评分,则利用该记录所对应的评分用户的活跃度和被评价项目的流行度进行相关性惩罚,从而提高数据稀疏环境下低流行度产品被推荐的概率。实验表明,所提算法在保证评分预测精度的情况下提升了推荐结果的多样性和新颖性。     

一种改进的协同过滤推荐算法

协同过滤推荐算法是电子商务推荐系统中应用最成功的推荐技术之一,而影响协同过滤推荐算法准确率的关键因素是用户相似性度量方法。针对传统相似性度量方法没有考虑共同评分项数量对推荐质量的影响,将用户之间的共同评分项数量作为相似性计算的一个重要指标,从而得到一种改进的相似性度量方法。但这仍然不能解决数据稀疏带来的推荐质量下降的问题,鉴于此,在上述改进的基础上,提出了利用复杂网络中的结构相似性来度量用户之间相似性的方法,使计算结果更具实际意义和准确性。实验表明,通过这些改进能够有效避免传统方法带来的弊端,提高系统的推荐质量。     

Managing dual warehouses with an incentive policy for deteriorating items

Distributors in a supply chain usually limit their own warehouse in finite capacity for cost reduction and excess stock is held in a rent warehouse. In this study, we examine inventory control for deteriorating items in a two-warehouse setting. Assuming that there is an incentive offered by a rent warehouse that allows the rental fee to decrease over time, the objective of this study is to maximise the joint profit of the manufacturer and the distributor. An optimisation procedure is developed to derive the optimal joint economic lot size policy. Several criteria are identified to select the most appropriate warehouse configuration and inventory policy on the basis of storage duration of materials in a rent warehouse. Sensitivity analysis is done to examine the results of model robustness. The proposed model enables a manufacturer with a channel distributor to coordinate the use of alternative warehouses, and to maximise the joint profit of the manufacturer and the distributor.     

基于线性组合文本特征选择方法*

当前,常用文本分类特征选择算法主要通过某种评价函数来计算单个特征对类别的区分能力,由于仅考虑了特征和类别之间的关联性,忽略了特征与特征之间的相关性,从而导致特征集存在冗余。针对这一问题,本文提出了一种新的用于文本分类的特征选择算法,该算法可以帮助选出类别区分能力强,特征之间关联性弱的特征。实验证实,该算法的性能要优于传统的特征选择算法。     

Visual Foxpro中防止关联数据库的不彻底数据更新

提出如何利用 TTS技术防止关联数据库关联更新的不彻底 ,并以一个实例对其实现过程进行了具体的说明。     

A proteome analysis of the dorsolateral prefrontal cortex in human alcoholic patients

Alcoholic patients commonly experience cognitive decline. It is postulated that cognitive dysfunction is caused by an alcohol-induced region-selective brain damage, particularly to the prefrontal region, and grey and white matter may be affected differently. We used a proteomics-based approach to compare protein expression profiles of the dorsolateral prefrontal cortex (Brodmann area 9 (BA9)) from human alcoholic and healthy control brains. Changes in the relative expression of 110 protein 'spots' were identified in the BA9 grey matter, of which 54 were identified as 44 different proteins. In our recent article, 60 protein spots were differentially expressed in the BA9 white matter and 18 of these were identified (Alexander-Kaufman, K., James, G., Sheedy, D., Harper, C., Matsumoto, I., Mol. Psychiatry 2006, 11, 56-65). Additional BA9 white matter proteins are identified here and discussed in conjunction to our grey matter results. Thiamine-dependent enzymes transketolase and pyruvate dehydrogenase (E1β ubunit) were among the proteins identified. To our knowledge, this is the first time a disruption in thiamine-dependent enzymes has been demonstrated in the brains of 'neurologically uncomplicated' alcoholics. By identifying protein expression changes in prefrontal grey and white matter separately, hypotheses may draw upon more mechanistic explanations as to how alcoholism causes the structural alterations associated with alcohol-related brain damage and cognitive dysfunction.     

综合评标法在水利工程检测项目招标投标中的应用

本文主要论述综合评标法是水利工程检测项目评标中较为实用的一种方法。本文建立了综合评分法模型,并通过实际案例,介绍其评分过程。     

武器装备科研项目科技成果评估指标及方法研究

以装备科研科技成果评估指标体系和评估手段为主要研究对象,力求建立一套操作方便、可以量化、科学合理的评估体系,并采用专家评估法对科技成果的形成过程进行综合评估,为强化科技成果过程管理、提高评估质量和公平性提供方法途径。     

基于事件关联电位脑机接口的电视遥控异步系统

本文设计了基于事件关联电位脑机接口的脑电信号预处理、特征提取、分类识别实时算法,开发了具有通讯功能的遥控器,实现了脑机接口电视遥控的异步系统.受试者可以用脑电波来遥控电视选择频道和调整音量,这为重症瘫痪病人拓展其与自然的直接交流开辟了新的通道.5位健康的受试者参与了训练实验和在线实验,实验结果表明经过特定的训练,受试者均可有效控制该脑机接口电视遥控系统,其统计平均准确率达87％,平均传输速率(ITR)达35 bits/min.     

涉外群体与民族精神弘扬的关系探析

涉外群体是民族精神的继承者、演绎者和创新者，为此，我们应在涉外群体中广泛开展弘扬和培育民族精神的教育，进而推动整个民族精神的培育和弘扬。