基于TDT技术的Web主题搜索分析与设计

提出了一种结合最新TDT技术、基于增强学习的优先Web环境主题搜索策略,并以此设计主题搜索器系统。该系统通过引入基于领域知识的TDT文本分类技术,大大改进了基于关键字的Naive Bayes模型主题相似性判别的准确性;通过引入基于增强学习的页面评估函数特征化主题Web环境,有效地提高了稀有信息的搜索能力。试验结果表明,该系统具有较高的实用性。     

Hierarchical bayesian models for regularisation in sequential learning

We show that a hierarchical Bayesian modeling approach allows us to perform regularization in sequential learning. We identify three inference levels within this hierarchy: model selection, parameter estimation, and noise estimation. In environments where data arrive sequentially, techniques such as cross validation to achieve regularization or model selection are not possible. The Bayesian approach, with extended Kalman filtering at the parameter estimation level, allows for regularization within a minimum variance framework. A multilayer perceptron is used to generate the extended Kalman filter nonlinear measurements mapping. We describe several algorithms at the noise estimation level that allow us to implement on-line regularization. We also show the theoretical links between adaptive noise estimation in extended Kalman filtering, multiple adaptive learning rates, and multiple smoothing regularization coefficients.     

一种基于强化学习的学习Agent

强化学习通过感知环境状态和从环境中获得不确定奖赏值来学习动态系统的最优行为策略,是构造智能Agent的核心技术之一,在面向Agent的开发环境AODE中扩充BDI模型,引入策略和能力心智成分,采用强化学习技术实现策略构造函数,从而提出一种基于强化学习技术的学习Agent,研究AODE中自适应Agent物结构和运行方式,使智能Agent具有动态环境的在线学习能力,有效期能够有效地满足Agent各种心智要求。     

Concept mapping your Web searches: a design rationale and Web-enabled application

Although it has become very common to use World Wide Web‐based information in many educational settings, there has been little research on how to better search and organize Web‐based information. This paper discusses the shortcomings of Web search engines and Web browsers as learning environments and describes an alternative Web search environment that combines a concept mapping and a data mining technique to address their drawbacks.     

An adaptive bi-flight cuckoo search with variable nests for continuous dynamic optimization problems

This paper presents an adaptive bi-flight cuckoo search algorithm for continuous dynamic optimization problems. Unlike the standard cuckoo search which relies on Levy flight, the proposed method uses two types of flight that are chosen adaptively by a learning automaton to control the global and local search ability of the method during the run. Furthermore, a variable nest scheme and a new cuckoo addition mechanism are introduced. A greedy local search method is also integrated to refine the best found solution. An extensive set of experiments is conducted on a variety of dynamic environments generated by the moving peaks benchmark, to evaluate the performance of the proposed approach. Results are also compared with those of other state-of-the-art algorithms from the literature. The experimental results indicate the effectiveness of the proposed approach.     

A feature-free search query classification approach using semantic distance

When classifying search queries into a set of target categories, machine learning based conventional approaches usually make use of external sources of information to obtain additional features for search queries and training data for target categories. Unfortunately, these approaches rely on large amount of training data for high classification precision. Moreover, they are known to suffer from inability to adapt to different target categories which may be caused by the dynamic changes observed in both Web topic taxonomy and Web content. In this paper, we propose a feature-free classification approach using semantic distance. We analyze queries and categories themselves and utilizes the number of Web pages containing both a query and a category as a semantic distance to determine their similarity. The most attractive feature of our approach is that it only utilizes the Web page counts estimated by a search engine to provide the search query classification with respectable accuracy. In addition, it can be easily adaptive to the changes in the target categories, since machine learning based approaches require extensive updating process, e.g., re-labeling outdated training data, re-training classifiers, to name a few, which is time consuming and high-cost. We conduct experimental study on the effectiveness of our approach using a set of rank measures and show that our approach performs competitively to some popular state-of-the-art solutions which, however, frequently use external sources and are inherently insufficient in flexibility.     

Searching the Web with Queries

In this paper we study the problem of searching the Web with online learning algorithms. We consider that Web documents can be represented by vectors of n boolean attributes. A search engine is viewed as a learner, and a user is viewed as a teacher. We investigate the number of queries a search engine needs from the user to search for a collection of Web documents. We design several efficient learning algorithms to search for any collection of documents represented by a disjunction (or a conjunction) of relevant attributes with the help of membership queries or equivalence queries.     

自适应最优搜索算法的网络蜘蛛的设计与实现

主题搜索引擎NonHogSearch改进了采用最优搜索算法的网络蜘蛛的搜索过程,控制了搜索的贪婪程度;并引入网页信噪比概念,从而判断网页是否属于所要搜索的主题页面;进一步,NonHogSearch在爬行过程中自动更新链接的权重,当得到主题相关页面时产生回报,将回报沿链接链路逆向反馈,更新链路上所有链接的Q值,这样避免了网络蜘蛛过早陷入Web搜索空间中局部最优子空间的陷阱,并通过并行方式实现多条链路的同时搜索,改进了搜索引擎的性能。实验证实了该算法在查全率与查准率两方面都有一定的优越性。     

Towards adaptive Web sites: conceptual framework and case study

The creation of a complex Web site is a thorny problem in user interface design. In this paper we explore the notion of adaptive Web sites: sites that semi-automatically improve their organization and presentation by learning from visitor access patterns. It is easy to imagine and implement Web sites that offer shortcuts to popular pages. Are more sophisticated adaptive Web sites feasible? What degree of automation can we achieve?To address the questions above, we describe the design space of adaptive Web sites and consider a case study: the problem of synthesizing new index pages that facilitate navigation of a Web site. We present the PageGather algorithm, which automatically identifies candidate link sets to include in index pages based on user access logs. We demonstrate experimentally that PageGather outperforms the Apriori data mining algorithm on this task. In addition, we compare PageGather's link sets to pre-existing, human-authored index pages.