科学网

 找回密码
  注册

tag 标签: recommendation

相关帖子

版块 作者 回复/查看 最后发表

没有相关内容

相关日志

How to pick one student out of 5+ applicants?
热度 2 zuojun 2013-7-19 11:44
站着说话,不嫌腰痛 。Because I am not a professor, I cannot have any students. All I write here is my "day dream," WHAT IF I were a professor and had funding to support one Ph.D student. How should I pick this student from more than five applicants? I will take each recommendation letter seriously. (I understand that letters from China may not be written by the senders. I was asked to draft a letter by Prof. L when I asked him for a letter to send me to the US in 1985. This is also not uncommon for US professors.) If I know the professor who wrote the letter and respect him, and if the recommendation is strong, I would pick his student/staff. Nothing else matters. It's that simple. If I don't know the people who wrote the letter, I would ask my colleagues who may know the letter sender. Again, you can see how much I rely on recommendation. Too much, maybe. If an applicant is from a country that I don't have any knowledge, I would reach out to colleagues from this country. In fact, I was asked a lot about Chinese students during my first 10 years in the US, as if I was supposed to know every Chinese in physical oceanography. (I actually did know many of them.) GPAs should matter, but not as much as the letter. The ranking of the school where the student is/was? I don't think so; probably because I myself was not from a top-10 school. By the way, I don't like such email, starting with "Dear Sir, ..." If a student is writing to ME, he or she should at least know who I am. (I know I am nobody, but if you want to be my student, don't you think you should know what I do for a living???) To wrap up, and to make you feel you didn't really waste all your time reading this Blog, I did have funding for a post doc once, many years ago. How did I pick him out of N applications? The letter; yes, the letter from a well known colleague in the field.
个人分类: Thoughts of Mine|3178 次阅读|4 个评论
《针对长尾的推荐系统》笔记
poson 2012-4-10 12:55
背景: 作者是ebay研究实验室的Sr. Director Head. 2005年加入ebay。 加入Ebay之前是a startup focused on multi-attribute fuzzysearch and network CRM的联合创始人。 《Recommender Systems at the Long Tail》是作者对于ebay的推荐系统的一个总结。从宏观的买家,卖家,产品,时间等等维度去阐述ebay的推荐系统。而真正的相关技术在参考文献中。 摘要: 推荐系统组成电子商务网站的核心。在这篇论文中,我们对推荐系统采用一种自上而下的观点,明确挑战和机遇,明确建立电子商务平台的推荐系统的方法。我们用ebay作为范例,这里提供了创新的推荐的机会。经过如此,ebay面临关系高度稀疏的复杂局面。 介绍: 建立电子商务网站的常用方法:基于内容的模型,基于邻居的方法,使用矩阵分解的协同过滤,这些都是建立推荐的非常著名的方法。 从微观经济学上面说,我们可以把商品分为3类,同等的可以替换的,如可乐和百事;作为补充的,如ipod和ipod 面板。 有些购物者非常在意品牌,即使是买补充型产品的时候也会先考虑同品牌的产品。 ebay的规模: 1亿买家和卖家;1000万商品;30000以上的类目。从数据量上面比较,淘宝网的用户、商品都远远超过ebay了。 产品维度: 有一些类目是禁止的,如arms,酒精、烟草等。 卖家经常会对产品有一些个性化的描述,以便区别其他卖家并争取更多的曝光量和更好的价格。 对商品有很多分类:用过的,翻新的, 珍藏的、坏的。 买家维度: 买家的年龄、性别。 购买力、价格区间是可以分析的。 卖家维度: 卖家的商品在哪些类目。 好评率是否高,发货时间、描述是否属实都是买家经常考虑的条件。 买家和卖家握手: 买家和卖家的习惯可能不相同。买家搜索词和卖家设置的标题可能不一致。 机遇和挑战: 买家在网站上面要经过很多个时间段。例如:搜索;寻找;观察;重新浏览;出价;购买;为感兴趣的物品买单。这里面的每个阶段,都是推荐系统大有作为的地方。 推荐系统可以利用的信息:query、类目、产品或者物品,甚至卖家和买家信息。 5个W,一个H : 参考 What? 首页有过去的购买信息,流行的信息,能够吸引用户或者让用户回忆起潜在的购买欲望。 Where? 不同的上下文有不同的算法。 不同页面的推荐算法,推荐的过滤条件,甚至检索的数据集合也是不一样的。 When: 购买的时间窗口。 衰减因子。 Why: 给出推荐的原因。购买了还购买,浏览了还浏览,收藏了还收藏等等。 给出的这些原因都是真实的原因吗? Who: 相对于无经验的买家来说,推荐对于一个非常有经验的买家或者卖家来说可能是无用的,甚至是不受欢迎的。 对于ebay来说,power买家的推荐效果比偶尔的买家效果要差。 如果把推荐系统看作是有预算限制的,意思是推荐的次数不是越多越好。那么对于某些用户,某些场景,可以不出现推荐。这样对于整体的购买转化率更高。这个太难衡量了吧“? 抓取合适的买家维度是比较重要的。 How: 主要介绍矩阵分解。 user-item矩阵 query-item矩阵 item的聚类问题。 基于内容的推荐可以用于冷启动问题。 针对突发流行的物品的识别和推荐。 这篇文章也是neel对自己工作的总结,文章末尾的论文大多数都有他自己的参与。
个人分类: 推荐系统|2863 次阅读|0 个评论
review: An IncentiveCompatible Distributed Recommendation
jiangdm 2011-12-26 15:46
review: An IncentiveCompatible Distributed Recommendation
An IncentiveCompatible Distributed Recommendation Model Jose M. Vidal Proceeding of to 6th International Workshop on Trust, Privacy, Deception, and Fraud in Agent Societies, 2003 ABSTRACT Our research is concerned with the study and development of incentive-compatible exchange mechanisms for recommendations in a multiagent system. These mechanism will allow and motivate agents to create an economy of ideas, where agents trade recommendations between themselves. In this paper we present a domain model and an incentivecompatible protocol for information exchange. Our model captures a subset of the realities of recommendation exchanges in the Internet. We provide an algorithm that selfish agents can use for deciding whether to exchange recommendations and with whom, that is, they can decide who they can trust to provide adequate recommendations. We analyze this algorithm and show that, under certain common circumstances, the agents’ rational choice is to exchange recommendations. Finally, we have implemented our model and algorithm and tested the performance of various populations. Our results show that both the social welfare and the individual utility of the agents is increased by participating in the exchange of recommendations. General Terms: Learning in Multiagent Systems, Recommender Systems, Trust 1. INTRODUCTION recommender systems the drawback of recommender systems: centralized implementations. the author's goal : to find ways to enable the emergence of a truly distributed recommender system in an Internet populated by selfish agents. incentive protocol design the research focus: under which circumstances should an agent give a recommendation to another? the organization of this paper: 1) Section2 describes a formal model to abstract the problem and its situation. 2) Section 3 derive some analytical results from this model. 3) Section 4 show the model simulation and test results. 4) Section 5 shows some work related to our research. 2. THE MODEL formal logic the utility i receives for reading d is given by: the expected value of Bayes Theorem: Tit-for-Tat to be the evolutionary stable strategy a Prisoner’s Dilemma matrix 2.1 An Agent’s Choice 3. MODELING USER PREFERENCES Netlogo 4. IMPLEMENTATIONANDTESTRESULTS source code: http://jmvidal.cse.sc.edu/netlogomas/ 4.1 Standard Agents clustering probability 4.2 Greedy Agents 4.3 Results Summary communities 5. RELATED WORK PHOAKS , the Referral Web 6. CONCLUSION author's work: 1) presented a domain model that captures the most important aspects of the distributed recommendations scenario\ 2) analyzed this model and showed that engaging in an exchange is the rational choice as long as the agent believes that the other agent has interests that have proven to be sufficiently similar 3) gave an algorithm that agents can use for deciding when to exchange recommendations and with whom 4) tested our algorithm on a various simulated scenarios. I comment: I don't understand the meanings of this paper distributedrec.nlogo An IncentiveCompatible.pdf Meanwhile, I read some code of 于同奎, but I don't comprehensive its essence. 惩罚与合作——一个来自人工社会的启示.pdf
个人分类: Econometrics|1 次阅读|0 个评论

Archiver|手机版|科学网 ( 京ICP备07017567号-12 )

GMT+8, 2024-5-18 16:37

Powered by ScienceNet.cn

Copyright © 2007- 中国科学报社

返回顶部