Catálogo de publicaciones - libros

More and more accessibility and usability guidelines are being proposed, especially for Web applications. Developers and designers are experiencing an increasing need for tools able to provide them with flexible support in selecting, editing, handling and checking guidelines. In this paper, we present an environment for addressing such issues. In particular, an interactive editor has been designed to assist designers and evaluators in abstracting and specifying new and existing guidelines in an XML-based Guideline Abstraction Language (GAL). Our tool has been designed in such a way to be able to check any guidelines specified in this language without requiring further changes in the tool implementation.

In this paper, we present a verification framework for security policies of Web designs. The framework is based on the transformation of the models that conform the system design into a formalism where further analysis can be performed. The transformation is specified as a triple graph transformation system, which in addition creates mappings between the elements in the source and target models. This allows the back-annotation of the analysis results to the original model by means of triple graphical patterns. The verification mechanisms are provided by the designer of the Web design language, together with the language specification. However, the complexities of the formalisms are hidden to the developer who uses the language.

As case study, we apply these ideas to Labyrinth, a domain specific language oriented to the design of Web applications. The analysis is done by a transformation into the Petri nets formalism, and then performing model checking on the coverability graph. The framework is supported by the meta-modelling tool AToM.

Due to resource constraints, Web archiving systems and search engines usually have difficulties keeping the local repository completely synchronized with the Web. To address this problem, sampling-based techniques periodically poll a subset of webpages in the local repository to detect changes on the Web, and update the local copies accordingly. The goal of such an approach is to discover as many changed webpages as possible within the boundary of the available resources. In this paper we advance the state-of-art of the sampling-based techniques by answering a challenging question: We propose a set of sampling policies with various downloading granularities, taking into account the link structure, the directory structure, and the content-based features. We also investigate the update history and the popularity of the webpages to adaptively model the download probability. We ran extensive experiments on a real web data set of about 300,000 distinct URLs distributed among 210 websites. The results showed that our sampling-based algorithm can detect about three times as many changed webpages as the baseline algorithm. It also showed that the changed webpages are most likely to be found in the same directory and the upper directories of the changed sample. By applying clustering algorithm on all the webpages, pages with similar change pattern are grouped together so that updated webpages can be found in the same cluster as the changed sample. Moreover, our adaptive downloading strategies significantly outperform the static ones in detecting changes for the popular webpages.

We propose a formal model, representing the navigation behavior of a Web application as the Kripke structure, and an approach to test generation. The behavior model can be constructed from the object structure of a Web application and then a set of test sequences is derived automatically from the behavior model with respect to some coverage criteria for the object structure by using the model checking’s capability to construct counter-examples.

Models are considered an essential step in capturing system behavior and simplifying the analysis required to check or improve the quality of software. Verification and testing of websites requires effective modelling techniques that address the specific challenges of web applications (WAs). In this study we survey 21 different modelling methods used in website verification and testing. Based on our survey, a categorization, comparison and evaluation for such models and methods is provided.

Current conceptual models and methodologies for Web applications concentrate on content, navigation, and service modeling. Although some of them are meant to address semantic web applications too, they do not fully exploit the whole potential deriving from interaction with ontological data sources and and from Semantic annotations. This paper proposes an extension to Web application conceptual models toward Semantic Web. We devise an extension of the WebML modeling framework that fulfills most of the design requirements emerging for the new area of Semantic Web. We generalize the development process to cover Semantic Web and we devise a set of new primitives for ontology importing and querying. Finally, an implementation prototype of the proposed concepts is proposed within the commercial tool WebRatio.

To build high-quality personalized Web applications developers have to deal with a number of complex problems. We look at the growing class of personalized Web Applications that share three characteristic challenges. Firstly, the semantic problem of how to enable content reuse and integration. Another problem is how to move away from a sluggish static interface to a responsive dynamic one as seen in regular desktop applications. The third problem is adapting the system into a multi-device environment. For this class of personalized Web applications we look at an example application, a TV recommender called SenSee, in which we solve these problems in a metadata-driven way. We go into depth in the techniques we used to create a solution for these given problems, where we particularly look at utilizing the techniques of Web Services, Web 2.0 and the Semantic Web. Moreover, we show how these techniques can also be used to improve the core personalization functionality of the application. In this paper we present our experience with SenSee to demonstrate general engineering lessons for this type of applications.

Social bookmarking services have become recently popular in the Web. Along with the rapid increase in the amount of social bookmarks, future applications could leverage this data for enhancing search in the Web. This paper investigates the possibility and potential benefits of a hybrid page ranking approach that would combine the ranking criteria of PageRank with the one based on social bookmarks in order to improve the search in the Web. We demonstrate and discuss the results of analytical study made in order to compare both popularity estimates. In addition, we propose a simple hybrid search method that combines both ranking metrics and we show some preliminary experiments using this approach. We hope that this study will shed new light on the character of data in social bookmarking systems and foster development of new, effective search applications for the Web.

In this paper, we propose a new method for designing rich internet applications. The design process uses results from an object-oriented analysis and employs interaction spaces as the basic abstraction mechanism. State diagrams are employed as refinements of interaction spaces and task models to specify synchronization events and follow up actions on the client and server side. The notation is based on UML.

Rich Internet Applications (RIAs) are reshaping the way in which the Web works. They change not only the appearance of the Web interfaces, but also the behavior of applications, permitting novel operations, like data distribution, partial page computation, and disconnected work. In this paper we try to understand the differences between the behavior of traditional dynamic Web applications and RIAs, considering the WebML modeling language and its actual implementation.