In this paper, we compare several deep and surface state-of-the-art machine learning methods for risk prediction in problems that can be modelled as a trajectory of events separated by irregular time intervals. Trajectories are the abstract representation of many real-life data, such as patient records, student e-tivities, online financial transactions, and many others. Given the continuously increasing number of machine learning methods to predict future high-risk events in these contexts, we aim to provide more insight into reproducibility and applicability of these methods when changing datasets, parameters, and evaluation measures. As an additional contribution, we release to the community the implementations of all compared methods.

This paper presents MILA, a prototype interactive Learning Analytics tool for the Moodle learning management system that has been developed to support the analysis and improvement of the teaching and learning processes in the e-learning environment of the University of Rome Unitelma Sapienza. MILA offers a variety of interactive and real-time data visualizations that provide statistics, trends, and insight information both on the Moodle-based virtual learning environment as a whole, and on each course included in it. In addition to Moodle standard logs, MILA is able to analyze tracking data generated by SCORM-compliant learning objects and to measure the duration of the related user sessions. Although MILA has been developed as a Moodle plugin, its software architecture and analysis models can be re-used and adapted to develop a learning analytics tool for any SCORM-compliant learning management system.

The growth in use of mobile phones to communicate and access sensitive resources drives the research of new approaches for protecting smartphones from all the possible attacks deriving from malicious software. Moreover, the continuous emerging of new and sophisticated malware makes current solutions to protect mobile phones inadequate shortly after being implemented. In this paper a new approach for run-time malware detection is proposed. It consists in analyzing system call traces gathered from malware and trusted applications to identify a set of relationships and recurring execution patterns that characterize their respective behavior. The characterization of the malware behaviour is expressed in terms of declarative constraints between system calls and can be used to identify similarities across malware families, detect malware variants within the same family, and to build trees of malware families based on their similarities. The effectiveness and efficiency of the approach have been assessed using a dataset of more than 1500 between trusted and malicious applications across six malware families. The results show that the proposed approach exhibits a very good discriminating ability exploitable for both malware detection and the study of malware evolution.

Websites built using Web Content Management Systems (WCMSs) usually provide their users with three types of access structures to surf their contents: indexes of categories, breadcrumb trails, and sitemaps. In addition, to find contents of his/her interest, a user can perform more or less advanced full-text searches. In this paper we propose an automatic approach to extend the navigation structure of websites developed using WCMSs with Semantic Navigation Maps (SNMs), a complementary navigation structure that enables linking and navigating contents based on their lexical similarity. The approach uses an information retrieval technique (namely, Latent Semantic Indexing) to identify lexical similarities between textual contents, and a fuzzy clustering algorithm to form groups of similar web pages. For each page of the website, a set of navigation links towards pages showing similar content and a measure of such similarity is provided. The paper presents the approach to generate SNMs, an implementation for the Joomla! open source WCMS, and the results of an empirical evaluation involving two real world websites built using this WCMS.

Online discussion forums represent, nowadays, one of the main asynchronous communication means and information sources over the Internet. The forum paradigm is adopted by the most followed websites, such as social networks and blogs. The effectiveness of discussion forums as information source, i.e., the capability to satisfy their users' information needs, depends on their information richness first, but also on how their are organized and effectively moderated. Forums organized and moderated by topics of discussion tend to host messages on related subjects and, overall, provide a classification of message threads which eases information search. In this paper we propose a semi-automatic approach to detect topics of discussion in a forum and to enhance its organization by providing a hierarchical topic-driven navigation view on its messages. We adopt Information Retrieval (IR) techniques, such as topic modeling, and formal concept analysis (FCA) to identify discussion topics and to provide a hierarchical topic-centered view on messages. We tested the validity of our approach on four forums of the e-learning platform of an Italian distance-learning university which provides around 20 moderated and unmoderated main forums followed actively by almost 5000 users, including students and teachers, each year. We validated the topics identification and messages to topics allocation process with a specific empirical experiment obtaining promising results.

SUMMARY This paper presents a semi‐automatic approach for the recovery and evolution of the design of existing Web applications. The proposed approach is structured in two main phases and is based on the Ubiquitous Web Applications (UWA) design framework, a methodology and a set of models and tools for the user‐centered design of multichannel context‐aware Web applications. In the first phase a representative set of the application's front‐end Web pages are analyzed to abstract the ‘as‐is’ design model of the application according to the UWA methodology. In the second phase, the recovered design model is evolved to define the ‘to be’ version of it. This evolution activity considers the up‐to‐date requirements available for the application and UWA design guidelines to identify shortcomings and opportunities of improvement in the ‘as‐is’ design. The reverse modeling phase exploits clustering and clone detection techniques and is supported by the RE‐UWA tool, an Eclipse IDE customized to implement the reverse engineering process defined to extract formal UWA models expressed as instances of a MOF metamodel. The forward design phase is supported by a set of UWA modeling tools that are built on top of the Eclipse Modeling Framework (EMF) and the Eclipse Graphical Modeling Framework (GMF). The proposed design recovery and evolution approach is applied to four real‐world Web applications and the obtained results are also presented in the paper. Copyright © 2012 John Wiley & Sons, Ltd.

One of the main characteristics of most Web applications is their high dynamism. Once implemented and deployed for the first time, new functionalities are added to meet new or changed requirements. Some of these functionalities may appear on the Web in response to an unexpected event, or phenomena (such as a natural calamity) after which they are removed. Some others are activated periodically, to coincide with a particular date, or period of the year (such as, return to school, Christmas holidays, etc.). Implementing such volatile functionalities usually impacts on a number of aspects of a Web application, including content, navigation, presentation, business processes, and user operations. Their cyclic activation/deactivation, which requires repetitive changes in the application code, may be the cause of waste of effort and application quality deterioration, up to incorrect functioning. In this paper, we present an approach to decouple the design and implementation of volatile functionalities from that of stable ones, i.e. the core functionalities of the application. The approach is instantiated in the context of the Object-Oriented Hypermedia Design Method (OOHDM), but its principles and related techniques are generally applicable to any other Web engineering method. We show how our approach enables the deployment and removal of these functionalities in a cost-effective and safe way and at runtime, thus providing business agility. A framework to classify volatile functionalities and a number of examples are also reported.

Firefox and Chrome are two very popular open source Web browsers, implemented in C/C++. This paper analyzes what topics were discussed in Firefox and Chrome bug reports over time. To this aim, we indexed the text contained in bug reports submitted each semester of the project history, and identified topics using Latent Dirichlet Allocation (LDA). Then, we investigated to what extent Firefox and Chrome developers/contributors discussed similar topics, either in different periods, or over the same period. Results indicate a non-negligible overlap of topics, mainly on issues related to page layouting, user interaction, and multimedia contents.

Rich Internet applications (RIAs) combine the simplicity of the hypertext paradigm with the flexibility of desktop interfaces. The quick emergence of these applications is driving a new (r)evolution in the Webfield. Building RIAs from scratch is often unfeasible because companies do not want to loose their investments in legacy Web software; additionally, most users are still accustomed to the "old" Web interaction style. In this paper we present an evolutionary approach to transform conventional Web software into RIAs; we show how to apply the well known refactoring concept to seamless introduce rich interface functionality in a Web application. By applying refactoring at the model level, we make the transition more systematic and less prone to error. We briefly introduce the problem with a simple example, and then we describe two refactorings and present our approach to specify these refactorings at the interface design level.

Teaching academic courses to students with disabilities is a challenging task, particularly for academics who are presented with the teaching requirements and needs that this implies, for the first time. Courses in the field of engineering and computer science, by requiring a lot of handson practices and teamwork, further exacerbate the situation as how to provide an effective learning experience for these disabled students. This situation requires a higher-level commitment than normal, from both the teachers and students. This paper presents the experience gained from teaching courses that involved hearing-impaired students of an undergraduate software engineering and a programming language course in two different universities. Some of the challenges faced by both instructors and the students are identified and some possible solutions are described.

This special issue features extended versions of selected papers from the 8th IEEE International Symposium on Web Site Evolution (WSE 2006) that was held in Philadelphia PA, on 23-24 September 2006.The symposium was co-located with the 22nd IEEE International Conference on Software Maintenance (ICSM 2006).Since its inception in 1999, the Web Site Evolution (WSE) series of events have provided a forum for researchers and practitioners from the communities of Software Maintenance and Evolution and Web Engineering to present original work and discuss subjects related to the disciplined evolution of large-scale Web sites.Researchers and practitioners working in the areas of Web application design, development, maintenance, and evolution attend WSE to discuss results and exchange experiences about models, methods, tools, and technologies related to the above-mentioned areas.In particular, the last editions of WSE have represented a significant step in making the WSE community more and more interdisciplinary, building bridges with various areas such as communication, HCI, usability, and quality and maintenance.We wish to maintain and enrich this multi-faceted spirit of the community, as well as to reach and involve other researchers and practitioners in this effort.WSE began as a one-day workshop, but, thanks to the success in terms of attendance and number of submissions, in 2006 it expanded into a two-day symposium to include keynote presentations, technical sessions, working sessions, and panels discussions.Out of 31 submissions, 13 excellent papers were selected to be presented at the symposium.The accepted papers covered a broad range of topics of the whole life cycle of Web systems, from design to implementation, evaluation, and maintenance, including: Modeling and Architecture, Web Trends and Technology, Accessibility and User Behavior, Comprehension, Testing and Security.The WSE 2006 program also included two inspiring keynotes: 'Model Driven Evolution of Network-Centric Applications: Perspectives, Applications, and Issues' by Kostas Kontogiannis, and 'Knowing Your Online Readership, Organizing Your Communication' by Lorenzo Cantoni.After the symposium, five outstanding papers were selected by the program chairs for invitation to this special issue of the Journal of Software Maintenance and Evolution: Research and Practice.The authors of the selected papers were asked to prepare a significant extension on the symposium version of their papers.Each paper underwent a rigorous reviewing process, involving three independent reviewers and two rounds of revisions.Eventually, four papers were accepted for inclusion in this special issue, covering four different topics of Web systems maintenance and evolution: Comprehension, Testing, Empirical Studies, and Patterns.During Web application re-engineering, a common activity is to identify similar content located in different static and dynamically generated Web pages, so that the content can be more effectively reused.The paper 'Identifying Similar Pages of Web Applications using a Competitive Clustering

This paper reports on a case study of redesigning a legacy application for the Web using the Ubiquitous Web Applications Design Framework with an extended version of its Transaction Design Model (UWAT+). Web application design methodologies hold the promise of engineering high-quality and long-lived Web systems and rich Internet applications. However, many such techniques focus solely on green-field development, and do not properly address the situation of leveraging the value locked in legacy systems. The redesign process supported by UWAT+ holistically blends design recovery technologies for capturing the know-how embedded in the legacy application with forward design methods particularly well suited for Web-based systems. The case study highlights some of the benefits of using UWAT+ in this context, as well as identifying possible areas for improvement in the redesign process and opportunities for tool automation to support it.

Business Web applications are complex data- and operation-intensive Web applications intended to support business processes. In this kind of application, the user executes sets of activities organized into transactions (also generally called workflows) in order to accomplish one of his/her tasks or fulfill one of his/her goals. The way these transactions are structured, the properties associated with their component activities and the way each activity is implemented by the Web application are a consequence of the transaction design as well as the business rules implied by the business process. The Ubiquitous Web Applications (UWA) design framework explicitly includes a design activity and a related meta-model, called the Transaction Design Model, specifically focused on the conceptual design of Web application transactions (Web Transactions for short). This paper describes preliminary steps towards a revised and extended version of the UWA Transaction Design Model that emphasizes a user-centered approach, is easier to adopt and manages the information, navigation and operation aspects involved in a Web Transaction in a comprehensive and integrated way.