Massimiliano Giordano

Monitoring Online Tests through Data Visualization

We present an approach and a system to let tutors monitor several important aspects related to online tests, such as learner behavior and test quality. The approach includes the logging of important data related to learner interaction with the system during the execution of online tests and exploits data visualization to highlight information useful to let tutors review and improve the whole assessment process. We have focused on the discovery of behavioral patterns of learners and conceptual relationships among test items. Furthermore, we have led several experiments in our faculty in order to assess the whole approach. In particular, by analyzing the data visualization charts, we have detected several previously unknown test strategies used by the learners. Last, we have detected several correlations among questions, which gave us useful feedbacks on the test quality.

A system for visual role-based policy modelling

The definition of security policies in information systems and programming applications is often accomplished through traditional low level languages that are difficult to use. This is a remarkable drawback if we consider that security policies are often specified and maintained by top level enterprise managers who would probably prefer to use simplified, metaphor oriented policy management tools. To support all the different kinds of users we propose a suite of visual languages to specify access and security policies according to the role based access control (RBAC) model. Moreover, a system implementing the proposed visual languages is proposed. The system provides a set of tools to enable a user to visually edit security policies and to successively translate them into (eXtensible Access Control Markup Language) code, which can be managed by a Policy Based Management System supporting such policy language. The system and the visual approach have been assessed by means of usability studies and of several case studies. The one presented in this paper regards the configuration of access policies for a multimedia content management platform providing video streaming services also accessible through mobile devices.

Visual Computer-Managed Security: A Framework for Developing Access Control in Enterprise Applications

The Visual Computer Managed Security (Vicoms) framework assists programmers in coding access control for Java applications. Vicoms provides a transparent way of managing security aspects in enterprise-level applications, including legacy ones. It has been embedded within the Eclipse open source integrated development environment and used experimentally in several case studies, one of which is described in the article.

A visual language-based system for extraction-transformation-loading development

Data warehouse loading and refreshment is typically performed by means of complex software processes called extraction–transformation–loading (ETL). In this paper, we propose a system based on a suite of visual languages for mastering several aspects of the ETL development process, turning it into a visual programming task. The approach can be easily generalized and applied to other data integration contexts beyond data warehouses. It introduces two new visual languages that are used to specify the ETL process, which can also be represented by means of UML activity diagrams. In particular, the first visual language supports data manipulation activities, whereas the second one provides traceability information of attributes to highlight the impact of potential transformations on integrated schemas depending on them. Once the whole ETL process has been visually specified, the designer might invoke the automatic generation of an activity diagram representing a possible orchestration of it based on its dependencies. The designer can edit such a diagram to modify the proposed orchestration provided that changes do not alter data dependencies. The final specification can be translated into code that is executable on the data sources. Finally, the effectiveness of the proposed approach has been validated through a user study in which we have compared the effort needed to design an ETL process in our approach with respect to the one required with main visual approaches described in the literature.Copyright

Exploiting Interaction Features in User Intent Understanding

Understanding user intent during a web navigation session is a challenging topic, which is drawing the attention of many researchers in this area. The achievements of such research goals would have a great impact on many internet-based applications. For instance, if a search engine had the capability of capturing user intents, it could better suite the order of search results to user needs. In this context, the research has mainly focused on the analysis of user interactions with Search Engine Result Pages (SERPs) resulting from a web query, but most methods ignore the behavior of the user during the exploration of web pages associated to the links of the SERP s/he decides to visit. In this paper we propose a novel model that analyzes user interactions on such pages, in addition to the information considered by other mentioned approaches. In particular, captured user interactions are translated into features that are part of the input of a classification algorithm aiming to determine user informational, navigational, and transactional intents. Experimental results highlight the effectiveness of the proposed model, showing how the additional analysis it performs on visited web pages contributes to enhance user intent understanding.

Visual modelling of role-based security policies in distributed multimedia applications

The management of distributed multimedia systems is simplified when it is based on policies. The latter should be platform independent and expressed in terms of roles. Usually, they are defined through languages that conceptualize the hardware characteristics providing powerful abstraction on the technical components of a system. Unluckily, these languages are very difficult to use for nonexpert users. To support all the different types of users visual languages have been proposed. Following this paradigm, we propose a visual language hierarchy and a tool for specifying and implementing access and security policies according to the RBAC model.

Role based reengineering of Web applications

We present an approach based on roles and access policies to improve security management of Web applications. The approach first identifies the roles users have in the application, and then the software resources they can access based on the assigned role. Roles and resources are then used to design access policies by means of a visual language based tool providing a metaphor-oriented layer above the well-known role based access control (RBAC) model. A network infrastructure based on a policy enforcement point (PEP) and a policy decision point (PDP) is used to enforce these policies. The proposed approach has been used in a preliminary case study.

Capturing User’s Interest from Human-Computer Interaction Logging

Mining user’s expectations and interests has become the focus of many Internet-based application providers, such as those operating in the areas of social networks, search engines, e-commerce, and so forth. This is often accomplished by means of explicit feedbacks requested to end-users, which might yield distorted results due to the intrusive nature of this kind of approach. Thus, it would be desirable using implicit feedbacks, provide that they faithfully reflect user’s habits and expectations. In this paper we propose an approach to capture user’s feedbacks from their interaction actions while processing a document, with particular emphasis on web documents. To this end, we propose a new model to interpret mouse cursor actions, such as scrolling, movement, text selection, while reading web documents, aiming to infer a relevance value indicating how the user found the document useful for his/her purposes. We have implemented the proposed model through light-weight components, which can be easily installed within major web browsers as a plug-in. The components log mouse cursor actions that we have used as experimental data in order to validate the proposed model. The experimental results show that the proposed model is able to predict user feedbacks with an acceptable level of accuracy.

A Dialogue Interface for Investigating Human Activities in Surveillance Videos

In this paper we present a dialogue interface for investigating human activities in surveillance videos. The interface exploits the information computed by the recognition system to support users in the investigation process. The interaction dialogue is supported by a sketch language enabling users to easily specify various kinds of questions about both actions and states, and the nature of the response one wishes. The contribution of this research is twofold (1) proposing an intuitive interaction mechanism for surveillance video investigation, and (2) proposing a novel question–answering model to support users during the information-seeking process.