Fully automatic methods that extract lists of objects from the Web have been studied extensively. Record extraction, the first step of this object extraction process, identifies a set of Web page segments, each of which represents an individual object (e.g., a product). State-of-the-art methods suffice for simple search, but they often fail to handle more complicated or noisy Web page structures due to a key limitation – their greedy manner of identifying a list of records through pairwise comparison (i.e., similarity match) of consecutive segments. This paper introduces a new method for record extraction that captures a list of objects in a more robust way based on a holistic analysis of a Web page. The method focuses on how a distinct tag path appears repeatedly in the DOM tree of the Web document. Instead of comparing a pair of individual segments, it compares a pair of tag path occurrence patterns (called visual signals) to estimate how likely these two tag paths represent the same list of objects. The paper introduces a similarity measure that captures how closely the visual signals appear and interleave. Clustering of tag paths is then performed based on this similarity measure, and sets of tag paths that form the structure of data records are extracted. Experiments show that this method achieves higher accuracy than previous methods.

Automaticnewsextractionfromnewspagesisimportantin many Web applications such as news aggregation. However, the existing news extraction methods based on templatelevel wrapper induction have three serious limitations. First, the existing methods cannot correctly extract pages belonging to an unseen template. Second, it is costly to maintain up-to-date wrappers for a large amount of news websites, because any change of a template may invalidate the corresponding wrapper. Last, the existing methods can merely extract unformatted plain texts, and thus are not user friendly. In this paper, we tackle the problem of template-independent Web news extraction in a user-friendly way. We formalize Web news extraction as a machine learning problem and learn a template-independent wrapper using a very small number of labeled news pages from a single site. Novel features dedicated to news titles and bodies are developed. Correlations between news titles and news bodies are exploited. Our template-independent wrapper can extract news pages from different sites regardless of templates. Moreover, our approach can extract not only texts, but also images and animates within the news bodies and the extracted news articles are in the same visual style as in the original pages. In our experiments, a wrapper learned from 40 pages from a single news site achieved an accuracy of 98.1 % on 3, 973 news pages from 12 news sites.

We have developed an unsupervised framework for simultaneously extracting and normalizing attributes of products from multiple Web pages originated from different sites. Our framework is designed based on a probabilistic graphical model that can model the page-independent content information and the page-dependent layout information of the text fragments in Web pages. One characteristic of our framework is that previously unseen attributes can be discovered from the clue contained in the layout format of the text fragments. Our framework tackles both extraction and normalization tasks by jointly considering the relationship between the content and layout information. Dirichlet process prior is employed leading to another advantage that the number of discovered product attributes is unlimited. An unsupervised inference algorithm based on variational method is presented. The semantics of the normalized attributes can be visualized by examining the term weights in the model. Our framework can be applied to a wide range of Web mining applications such as product matching and retrieval. We have conducted extensive experiments from four different domains consisting of over 300 Web pages from over 150 different Web sites, demonstrating the robustness and effectiveness of our framework.

Abstract: Problems statement: Nowadays, many users use web search engines to find and gather information. User faces an increasing amount of various HTML information sources. The issue of correlating, integrating and presenting related information to users becomes important. When a user uses a search engine such as Yahoo and Google to seek specific information, the results are not only information about the availability of the desired information, but also information about other pages on which the desired information is mentioned. The number of selected pages is enormous. Therefore, the performance capabilities, the overlap among results for the same queries and limitations of web search engines are an important and large area of research. Extracting information from the web pages also becomes very important because the massive and increasing amount of diverse HTML information sources in the internet that are available to users and the variety of web pages making the process of information extraction from web a challenging problem. Approach: This study proposed an approach for extracting information from HTML web pages which was able to extract relevant information from different web pages based on standard classifications. Results: Proposed approach was evaluated by conducting experiments on a number of web pages from different domains and achieved increment in precision and F measure as well as decrement in recall. Conclusion: Experiments demonstrated that our approach extracted the attributes besides the sub attributes that described the extracted attributes and values of the sub attributes from various web pages. Proposed approach was able to extract the attributes that appear in different names in some of the web pages. Key words: HTML web pages, information extraction

using high-level structured queries for