Andrea Tundis

On the Reliability Analysis of Systems and SoS: The RAMSAS Method and Related Extensions

This paper aims at contributing to fill the lack of methods specifically conceived for addressing the analysis and verification of nonfunctional requirements. In particular, the attention is focused on system reliability, which is a key requirement to be satisfied particularly for mission-critical systems where system failures could cause even human losses. To this end, this paper presents an up-to-date version of RAMSAS, which is a recently proposed model-based method for the reliability analysis of systems through simulation. The present version of RAMSAS is the result of an intensive experimentation phase in several application domains (avionics, automotive, and satellite) that allowed for the improvement of the effectiveness of the method, particularly in the modeling of both the intended and dysfunctional system behaviors. Moreover, this paper discusses the specific issues that arise when moving from the reliability analysis of systems to that of systems of systems (SoSs) and proposes a possible extension of the RAMSAS method (called RAMSoS) that is able to address the identified issues and thus support the reliability analysis of SoSs through simulation.

Reliability analysis of an Attitude Determination and Control System (ADCS) through the RAMSAS method

Abstract Reliability analysis of modern large-scale systems is a challenging task which could benefit from the jointly exploitation of recent model-based approaches and simulation techniques to flexibly evaluate the system reliability performances and compare different design choices. In this context, RAMSAS, a model-based method which supports the reliability analysis of systems through simulation by combining the benefits of popular OMG modeling languages with wide adopted simulation and analysis environments, has been recently proposed. This paper shows the effectiveness of RAMSAS through a real case study concerning the reliability analysis of an Attitude Determination and Control System (ADCS) of a satellite.

Formal Requirements Modeling for Simulation-Based Verification

This paper describes a proposal on how to model formal requirements in Mo delica for simulation-based verification. The approach is implemented in the open source Modelica_Requirements library. It requires extensions to the Modelica language, that have been prototypically implemented in the Dymola and OpenModelica software. The design of the library is based on the FOrmal Requirement Modeling Language (FORM-L) defined by EDF, and on industrial use cases from EDF and Dassault Aviation. It uses 2- and 3valued temporal logic to describe requirements.

Towards Security as a Service (SecaaS): On the modeling of Security Services for Cloud Computing

The security of software services accessible via the Internet has always been a crosscutting non-functional requirement of uttermost importance. The recent advent of the Cloud Computing paradigm and its wide diffusion has given birth to new challenges towards the securing of existing Cloud services, by properly accounting the issues related to their delivery models and their usage patterns, and has opened the way to the new concept of Security as a Service(SecaaS), i.e. the ability of developing reusable software services which can be composed with standard Cloud services in order to offer them the suitable security features. In this context, there is a strong need for methods and tools for the modeling of security concerns, as well as for evaluation techniques, for supporting both the comparison of different design choices and the analysis of their impact on the behavior of new services before their actual realization. This paper proposes a meta-model for supporting the modeling of Security Services in a Cloud Computing environment as well as an approach for guiding the identification and the integration of security services within the standard Cloud delivery models. The proposal is exemplified through a case study.

Modeling and simulation for system reliability analysis: The RAMSAS method

The paper presents the up-to-date version of RAMSAS, a recently proposed model-based method for the reliability analysis of systems through simulation. RAMSAS can be easy plugged in various phases of a typical system development process ranging from the design to the testing phases so to complement other well-known and wide adopted techniques for system reliability analysis (e. g. FMECA, FTA, RBD) by providing additional analysis capabilities. The present version of RAMSAS is the result of an intensive experimentation phase in several application domains (avionics, automotive, satellite) which allowed improving the effectiveness of the method especially in the modeling of both the intended and dysfunctional system behavior. The paper concludes with a discussion about the specific aspects of the reliability analysis of System of Systems (SoS), and how RAMSAS can be further extended to effectively support it.

An integrated toolchain for model based functional safety analysis

The significant increase in the complexity and autonomy of the hardware systems renders the verification of the functional safety of each individual component as well as of the entire system a complex task and underlines the need for integrated, model based tools that would assist this process. In this paper the authors present such a tool, coupled with an approach to functional safety analysis, based on the integration of functional tests into the model itself. The analysis of the resulting model is done through a stochastic Bayesian model. This approach strives to both bypass the necessity for costly hardware testing and integrate the functional safety analysis into an intuitive component development process.

Requirement Verification and Dependency Tracing During Simulation in Modelica

Requirement verification is an important part of the development process, and the increasing system complexity has exacerbated the need for integrating this step into a formalized model driven development process, providing a dedicated methodology as well as tool support. In this paper the authors propose an extension for Modelica, an equation-based language for system modeling, that will allow to represent system requirements in the same formalism as the design model, thus reducing the need for transformations between different specialized formalisms, lowering maintenance and modification costs, and benefitting from the expression and simulation capabilities, as well as extensive tool support of Modelica. The object-oriented nature of the approach provides the advantages of modular design and hierarchical structuring of the requirement model. This paper also illustrates, with the help of an example, how requirement verification can be used alongside the simulation process to trace the components responsible for requirement violations. To this end, we introduce a formalism for expressing relationships between components and requirements, as well as a tracing algorithm.

A multi-language approach towards the identification of suspicious users on social networks

The use of IT technology for the planning and implementation of illegal activities has been gaining ground in recent years. Nowadays, through the web and the social media, it is possible not only to divulge advertising for the disclosure of illicit activities, but also to take action that in the past needed to have people in place and at the moment the activity took place. In fact, this phenomenon allows criminals to be less exposed to the risk of being discovered. Furthermore, the technology tends to encourage international collaborations, which makes the process of identifying illegal activities even more complex because of the lack of adequate tools that can operate effectively by considering multi-cultural aspects. Consequently, this evolving phenomenon towards cyber-crime requires new models and analysis techniques to address these challenges. In this context, the paper proposes an approach based on a multi-language model that aims to support the identification of suspicious users on social networks. It exploits the effectiveness of web translation services along with specific stand-alone libraries for normalizing user profiles in a common language. In addition, different text analysis techniques are combined for supporting the user profiles evaluation. The proposed approach is exemplified through a case study by analyzing Twitter users profile by showing step by step the overall process and related results.

Model-Based Dependability Analysis of Physical Systems with Modelica

Modelica is an innovative, equation-based, and acausal language that allows modeling complex physical systems, which are made of mechanical, electrical, and electrotechnical components, and evaluates their design through simulation techniques. Unfortunately, the increasing complexity and accuracy of such physical systems require new, more powerful, and flexible tools and techniques for evaluating important system properties and, in particular, the dependability ones such as reliability, safety, and maintainability. In this context, the paper describes some extensions of the Modelica language to support the modeling of system requirements and their relationships. Such extensions enable the requirement verification analysis through native constructs in the Modelica language. Furthermore, they allow exporting a Modelica-based system design as a Bayesian Network in order to analyze its dependability by employing a probabilistic approach. The proposal is exemplified through a case study concerning the dependability analysis of a Tank System.

CHALLENGES AND AVAILABLE SOLUTIONS AGAINST ORGANIZED CYBER-CRIME AND TERRORIST NETWORKS

Organized Crime (OC) and Terrorist Networks (TN) have risen to major and persistent threats for the European Union and its population. The IT growth of the past decade caused a migration of OC/TN to the cyber domain as well as the introduction of cybercrime. As a consequence, the technological dimensions of criminal activities are becoming more relevant and challenges ranging from the identification of criminal activities up to the understanding of engagement processes, are even more complicated. In this context, this paper aims to provide a discussion on OC and TN by pointing out organizational models, similarities, distinguishing features and differences in terms of their objectives. Furthermore, the main issues and available categories of solutions, in terms of models, methods and software tools are described. Finally, the importance of innovative digital and non-digital solutions is discussed as well as the current research directions are highlighted.