One of the research areas of great importance in Computer Science is the study of the semantics of concurrent reactive systems. These are systems that compute by interacting with their environment, and typically consist of several parallel components, ...

The ubiquitous reliance on software systems is increasing the need for ensuring their correctness. Runtime enforcement is a monitoring technique that uses moni- tors that can transform the actions of a system under scrutiny in order to alter its runtime ...

Relational Agents (RAs) are virtual anthropomorphic characters able to engage in multimodal (i.e. using both verbal and nonverbal behavior) face-toface interactions with users in real-time. RAs are also capable of establishing and maintaining a long-term ...

In the recent years, formal modeling and verification of realtime systems have become very important. Difficult-to-use modeling languages and inefficient analysis tools are the main obstacles to use formal methods in this domain. Timed actor model is ...

This thesis presents the NV-tree (Nearest Vector tree), which addresses thespecific problem of efficiently and effectively finding the approximatek-nearest neighbors within large collections of high-dimensional data points.The NV-tree is a very ...

In-network aggregation is an important paradigm for current and future networked systems, enabling efficient cooperate processing of aggregate information, while providing sub-linear scalability properties. However, security of this important class of ...

Concurrency as a phenomenon is observed in most of the current computer science trends. However the inherent complexity of analyzing the behavior of such a system is incremented due to the many different models of concurrency, the variety of applications ...