Ángel Viña

Semi-Automatic Wrapper Generation for Commercial Web Sources

Semi-automatic wrapper generation tools aim to ease the task of building structured views over semi-structured web sources. But the wrapper generation techniques presented up to date are unable to properly deal with sources requiring complex navigational sequences for accessing data. In this paper, we present WARGO, a semiautomatic wrapper generation tool, which has been used by non-programmer staff to successfully wrap more than 700 commercial web sources in several industrial applications. We describe our approach for wrapper generation and show the difficulties found with other systems for wrapping this kind of sources.

Experiences retrieving information in the world wide web

In this paper using the information obtained from the daily working of a Web directory, we attempt to expand the knowledge about the behavior of the users in order to improve and adapt the Internet search engines to their users. We have analysed more than 320,000 requests of the transaction log of a Spanish Web directory, focusing our attention, firstly, in the searches in order to confirm the main differences between Internet and traditional Information Retrieval systems. Furthermore, we have developed an exhaustive statistical analysis of searches, categories visited and documents viewed to achieve a mathematical pattern of behaviour for each one, and what it is more important, to establish a relationship between the variations in the behaviour of each one.

An alternative architecture for financial data integration

Exploring a new paradigm for mediated data integration.

The Wargo system: semi-automatic wrapper generation in presence of complex data access modes

Semi-automatic wrapper generation tools aim to ease the task of building structured views over Web sources. But the wrapper generation techniques presented to date show several weaknesses when dealing with the complex commercial Web sources of today, especially when constructing advanced navigational sequences for accessing data. We present Wargo, a semi-automatic wrapper generation tool, which has been used by non-programmer staff to successfully wrap more than 700 commercial Web sources in several industrial applications.

The denodo data integration platform

The world today is characterised by the proliferation of information sources available through media such as the WWW, databases, semi-structured files (e.g. XML documents), etc. Nevertheless, this information is usually scattered, heterogeneous and weakly structured, so it is difficult to process it automatically. DENODO Corporation has developed a mediator system for the construction of semi-structured and structured data integration applications. This system has already been used in the construction of several applications on the Internet and in corporate environments, which are currently deployed at several important Internet audience sites and large sized business corporations. In this extended abstract, we present an overview of the system and we put forward some conclusions arising from our experience in building real-world data integration applications, focusing in some challenges we believe require more attention from the research community.

Client-side deep Web data extraction

The problem of data extraction from the deep Web can be divided into two tasks: crawling the client-side and the server-side deep Web. The objective is to define an architecture and a set of related techniques to access the information placed in the client-side deep Web. This involves dealing with aspects such as JavaScript technology, nonstandard session maintenance mechanisms, client redirections, pop-up menus, etc. We use current browser APIs as building blocks and leverage them to implement novel crawling models and algorithms

Automatic wrapper maintenance for semi-structured web sources using results from previous queries

During the last years, significant attention has been paid to the problem of building wrappers for extracting data from semistructured web sources. Nevertheless, since web sources are autonomous, they may experience changes that invalidate the wrappers. In this paper, we present new heuristics and algorithms to address the problem of automatic wrapper maintenance. Our approach is based on collecting query results during wrapper operation and using them later to generate new sets of examples that can be used to induce a new wrapper when the source changes.

A comprehensive approach in performance evaluation for modern real-time operating systems

In real-time computing the accurate characterization of the performance and determinism that a particular real-time operating system/hardware combination can provide for real-time applications is essential. This issue is not properly addressed by existing performance metrics mainly due to the lack of completeness and generalization. In this paper we present a set of comprehensive, easy-to-implement and useful metrics covering three basic real-time operating system features: response to external events, intertask synchronization and resource sharing, and intertask data transferring. The evaluation of real-time operating systems using a set of fine-grained metrics is fundamental to guarantee that we can reach the required determinism in real-world applications.

Real-time multimedia systems

The expansion of multimedia networks and systems depends on real-time support for media streams and interactive multimedia services. Multimedia data are essentially continuous, heterogeneous, and isochronous, three characteristics with strong real-time implications when combined. At the same time, some multimedia services, like video-on-demand or distributed simulation, are real-time applications with sophisticated temporal functionalities in their user interface. We analyze the main problems in building such real-time multimedia systems, and we discuss-under an architectural prospect-some technological solutions especially those regarding determinism and efficient synchronization in the storage, processing, and communication of audio and video data.<<ETX>>

FINDER: a mediator system for structured and semi-structured data integration

Mediator systems aim to provide a unified vision over heterogeneous, distributed, structured and semi-structured data sources. We present FINDER, a mediator system which has been used for building several real-world data integration applications, both in the Internet and intranet domains. In this paper we provide an overview of the system and remark upon some of its distinctive features.