一种属性和评分的协同过滤混合推荐算法

传统协同过滤推荐算法仅仅根据稀疏的评分矩阵向用户推荐,存在推荐质量不高的问题。提出了一种属性和评分的协同过滤混合推荐算法。该算法由项目的类别属性计算项目之间基于属性的相似性,考虑到用户兴趣随时间的变化,构建评分时间权重的指数函数,并应用到项目之间的Pearson相关相似性中。通过权重因子加权项目之间基于属性的相似性和项目之间的Pearson相关相似性,然后计算基于项目属性的评分预测。描绘职业分类树,构建职业相似性模型,并与性别加权结合产生用户综合属性的相似性,得到基于用户属性的评分预测。最后,综合两者计算混合评分预测。在Movielens实验数据集下,实验结果表明提出的算法具有较好的平均绝对误差。     

一种结合项目属性的混合推荐算法

传统的协同过滤推荐算法中仅仅根据评分矩阵进行推荐,由于矩阵的稀疏性,存在推荐质量不高的问题.本文提出了一种结合项目属性相似性的混合推荐算法,该算法通过计算项目之间属性的相似性,并且与基于项目的协同过滤算法中的相似性动态结合,通过加权因子的变化控制两种相似性的比重来改善协同过滤中的稀疏性问题,并且将综合预测评分和基于用户的协同过滤预测评分相结合来提高推荐质量,最终根据综合评分来进行推荐.通过实验数据实验证明,该算法解决了协同过滤算法的矩阵稀疏性问题.     

基于共同评分和相似性权重的协同过滤推荐算法

协同过滤推荐算法是在电子商务推荐系统中应用最成功的推荐技术之一。提出了一种基于共同评分和相似性权重的协同过滤推荐算法。该算法选择用户的共同评分数据计算用户的相似性,选择项目被用户共同评分的数据计算项目的相似性,再分别计算基于用户以及项目算法的预测评分,然后通过相似性权重结合两者得到最终的预测结果,最后再根据预测结果产生推荐。实际数据的实验结果表明,提出的算法显著提高了预测准确度,从而提高了推荐质量。     

融合本体语义与用户属性的协同过滤算法

传统协同过滤推荐算法在处理海量数据时存在数据稀疏性和项目长尾效应,导致推荐精度较低。针对该问题,结合本体语义和用户属性,提出一种改进的协同过滤算法。利用本体计算项目之间的语义相似度,构建项目相似度矩阵,同时引入用户属性计算用户相似度矩阵。通过融合本体语义和用户属性形成用户-项目评分矩阵,并对该矩阵的预测评分进行加权处理,生成TOP-N推荐结果。实验结果表明,相比传统皮尔逊相似度计算协同过滤算法、基于本体语义的协同过滤算法和基于评分矩阵填充与用户兴趣的协同过滤算法,该算法的平均绝对误差较低,准确率较高,综合性能及新颖度较优。     

基于直接评分与间接评分的协同过滤算法

协同过滤面临着用户评分数据极为稀疏的问题,为改善不同稀疏程度数据上的推荐效果,提出基于直接评分与间接评分的协同过滤算法。针对直接评分,定义加权用户相似性和加权项目相似性度量标准,构造直接推荐用户集合与直接推荐项目集合,给出直接评分权重的计算方法;针对间接评分,构造相似评分集合,定义评分相似性度量标准。定义综合评分权重,在直接评分与间接评分的基础上得到最终推荐结果。大量实验结果表明,该算法在不同稀疏程度的数据上均具有较高的推荐质量。     

一种优化的基于项目评分预测的协同过滤推荐算法

通过分析在用户评分数据极端稀疏的情况下,现有的基于项目评分预测的协同过滤推荐算法中项目之间的相似性度量不准确以及新项目的冷开始问题,提出了一种优化的基于项目评分预测的协同过滤推荐算法。该算法在计算项目之间的相似性时,既考虑了项目的评分相似性,又考虑了项目的特征属性相似性。实验表明,优化后的算法使计算出的项目之间的相似性更准确,并有效地解决了新项目的推荐问题,使得数据稀疏性对推荐结果的负面影响变小,显著提高了系统的推荐质量。     

多属性协同过滤推荐在物流配送服务平台的应用

为了帮助用户选择尽可能满足其个性化偏好的物流配送服务,结合配送服务的多属性评分特点,本文构建了基于多属性协同过滤的推荐算法,对传统协同过滤算法进行了延伸与改进,首先预测目标用户对候选服务各属性的评分值,通过引入服务的个性化特征因子减小热门服务对用户相似度计算的误差,考虑到用户的服务属性评分存在波动性,使用信息熵将用户历史评分均值与协同过滤得到的预测值相结合进行修正,然后基于同一用户对不同属性评分波动性的差异,计算得到用户对服务所有属性的评分预测权重,将各属性的评分预测值与对应权重加权求和进行服务推荐.对配送服务交易的评分数据样本进行实验验证,在准确率和平均绝对误差指标上有较好的表现,将算法应用于物流配送服务平台,构建推荐系统,能够提高平台个性化服务能力.     

基于项目属性和云填充的协同过滤推荐算法

传统协同过滤推荐算法中经常因用户评分矩阵极端稀疏而导致相似性度量方法不准,推荐质量不高,针对这一问题,提出一种基于项目属性和云填充的协同过滤推荐算法。利用云模型对用户评分矩阵进行填充,在填充矩阵基础上,利用传统的相似性计算方法得到项目之间的评分相似性,同时结合项目属性,计算项目的属性相似性,通过加权因子得到项目的最终相似性,从而形成一种新的相似性度量方法。实验结果表明, 提出的算法可有效解决传统方法中由于数据稀疏所导致的相似性度量不准确的问题, 并显著地提高了算法的推荐精度。     

基于用户-项目的混合协同过滤算法

针对传统协同过滤方法中存在的冷启动和数据稀疏等问题,结合基于用户的协同过滤和基于项目的协同过滤提出一种混合协同过滤算法。在相似度的计算中提出改进算法来提高相似度计算的精确度;在预测未评分值时引入控制因子、平衡因子进行加权综合预测,最后再进行综合推荐。实验过程中采用Movie Lens数据集作为测试数据,同时采用平均绝对误差作为实验的测试标准。实验结果表明,基于用户-项目混合协同过滤算法在评分矩阵极度稀疏的环境下提高了推荐的性能,并能有效提高预测的精度。     

改进加权Slope one协同过滤推荐算法研究

协同过滤推荐是最成功的推荐技术之一,但数据稀疏性问题导致推荐准确度和推荐效率不高.针对这个问题,提出了一种改进的加权Slope one协同过滤推荐算法.计算用户之间的评分相似度,找出每个用户的最近邻;根据最近邻用户评分,使用基于用户的协同过滤和改进的加权Slope one算法的加权评分预测目标用户的未评分项目;给出推荐.实验过程中采用MovieLens数据集作为测试数据.实验结果表明:与原算法相比,算法提高了预测准确度,有效提高了推荐性能.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.