Publications

Masci P, Moniz H, Tedeschi A.  2008.  Services for fault-tolerant conflict resolution in air traffic management. SERENE '08: Proceedings of the 2008 RISE/EFTS Joint International Workshop on Software Engineering for Resilient Systems. :121–125. Abstract

Airborne Self-Separation is a new concept of dynamic management of air traffic flow, where pilots are allowed to select their flight paths in real-time. In this new operational concept, each aircraft is guided by an automated decision procedure and, based on the available information, enters into negotiations with surrounding aircraft in order to coordinate actions and avoid collisions. In this work, we explore the possibility of combining an approach based on Satisficing Game Theory together with fault-tolerant protocols to obtain a robust approach for conflict resolution and air traffic optimization in the context of Airborne Self-Separation.

Avvenuti M, Corsini P, Masci P, Vecchio A.  2007.  Opportunistic computing for wireless sensor networks. Mobile Adhoc and Sensor Systems, 2007. MASS 2007. IEEE Internatonal Conference on. :1–6. Abstract

Wireless sensor networks are moving from academia to real world scenarios. This will involve, in the near future, the design and production of hardware platforms characterized by low-cost and small form factor. As a consequence, the amount of resources available on a single node, i.e. computing power, storage, and energy, will be even more constrained than today. This paper faces the problem of storing and executing an application that exceeds the memory resources available on a single node. The proposed solution is based on the idea of partitioning the application code into a number of opportunistically cooperating modules. Each node contributes to the execution of the original application by running a subset of the application tasks and providing service to the neighboring nodes.

Corsini P, Masci P, Vecchio A.  2006.  Configuration and tuning of sensor network applications through virtual sensors. PerCom Workshops. :316–320. Abstract

Writing software for sensor networks requires full understanding of the physical phenomenon under observation. Nevertheless, in many cases knowing the details of the area of operation is difficult or unfeasible. This leads to the necessity of configuring and tuning the application executed on the sensor nodes even after the network has been deployed. We present a solution where a layer of computation is inserted between the application and the sensing equipment. This layer acts like a tiny interpreter and can be used to customize the behavior of already running applications. Experimental validation of the architecture and examples of use are also shown.

Corsini P, Masci P, Vecchio A.  2006.  VirtuS: a configurable layer for post-deployment adaptation of sensor network. ICWMC. :8. Abstract

Post-deployment adaptation of sensor networks is usually a necessity for several reasons, ranging from trivial deterioration of sensing hardware to unsatisfactory implementation of application logic. In this paper we present the architecture of VirtuS, a software component that can be incorporated into existing applications and remotely programmed to customize the behavior of sensor networks after deployment. Scenarios of use and experimental validation of the architecture are also included.

Avvenuti M, Corsini P, Masci P, Vecchio A.  2006.  Increasing the efficiency of preamble sampling protocols for wireless sensor networks. Proceedings of the First Mobile Computing and Wireless Communication International Conference, 2006. MCWC 2006.. :117–122. Abstract

Applications designed for event driven monitoring represent a challenging class of applications for wireless sensor networks. They are a special kind of monitoring applications, since they usually need low data rates, but also require mechanisms for low latency and asynchronous communication. In this paper we will focus on optimizations at the MAC layer that enable low energy consumption when contention-based protocols are adopted. We present B-MAC+, an enhanced version of a widely adopted MAC protocol, and we show that substantial improvements, in terms of network lifetime, can be reached over the original protocol.

Corsini P, Masci P, Vecchio A.  2006.  Experiences with the TinyOS Communication Library. Wireless Information Systems. :47-55. Abstract

TinyOS is a useful resource for developers of sensor networks. The operating system includes ready-made software components that enable rapid generation of complex software architectures. In this paper we describe the lessons gained from programming with the TinyOS communication library. In particular, we try to rationalize existing functionalities, and we present our solutions in the form of a communication library, called TComm-Lib.

Masci P.  2006.  Detecting data leakage in malicious Java applets. ReSIST Student Seminar. :81–84. Abstract

Web applets are programs dynamically loaded and executed inside the Internet browser of users' machine. They are used to extend the functionalities of web pages. Web applets can be associated with specific profiles granting access to information of users. As a consequence, web applets may possibly disclose, intentionally or by error, confidential information on public channels. We propose a technique to analyze the compiled code of web applets before execution. The technique is based on abstract interpretation. Data is associated with security levels and an iterative analysis is performed to trace information flows.

Bernardeschi C, Martini L, Masci P.  2004.  Java bytecode verification with dynamic structures. IASTED Conf. on Software Engineering and Applications. :559-564. Abstract

Java applets run on a Virtual Machine that checks code's integrity and correctness before execution using a module called Bytecode Verifier. Java Card technology allows Java applets to run on smart cards. Large memory space requirements of the verification process do not allow the implementation of a Bytecode Verifier embedded in the Java Card Virtual Machine. To address this feasibility problem, we propose a modified verification algorithm that optimizes the use of system memory. The algorithm, inspired to compilers techniques, partitions the code of the methods into control regions. In this way data structures can be dynamically allocated and the verification process can be applied locally to a subset of instructions.

Watson N, Reeves S, Masci P.  201.  Integrating user design and formal models within PVSio-Web. Workshop on Formal Integrated Development Environment (F-IDE 2018), EPTCS, to appear. Abstractmain201807200104.pdf

Creating formal models of interactive systems has wide reaching benefits, not only for verifying low-level correctness, but also as a tool for ensuring user interfaces behave logically and consistently. Despite this, tools for designing user experiences and tools for creating and working with formal models are typically distinctly separate systems. This work aims to bridge this divide by allowing the generation of state machine diagrams and formal models via a simple, interactive prototyping tool that mirrors the basic functionality of many modern digital prototyping applications.

Harrison M, Masci P, Campos JC.  2018.  Verification templates for the analysis of user interface software design. IEEE Transactions on Software Engineering (to appear). Abstractnewtemplates-r1v7b.pdfhttps://doi.org/10.1109/TSE.2018.2804939

The paper describes templates for model-based analysis of usability and safety aspects of user interface software design. The templates crystallize general usability principles commonly addressed in user-centred safety requirements, such as the ability to undo user actions, the visibility of operational modes, and the predictability of user interface behavior. These requirements have standard forms across different application domains, and can be instantiated as properties of specific devices. The modeling and analysis process is carried out using the Prototype Verification System (PVS), and is further facilitated by structuring the specification of the device using a format that is designed to be generic across interactive systems. A concrete case study based on a commercial infusion pump is used to illustrate the approach. A detailed presentation of the automated verification process using PVS shows how failed proof attempts provide precise information about problematic user interface software features.

Bernardeschi C, Domenici A, Masci P.  2017.  A PVS-Simulink Integrated Environment for Model-Based Analysis of Cyber-Physical Systems. IEEE Transactions on Software Engineering. (In Press) Abstract07900400.pdfhttps://doi.org/10.1109/TSE.2017.2694423

This paper presents a methodology, with supporting tool, for formal modeling and analysis of software components in cyber-physical systems. Using our approach, developers can integrate a simulation of logic-based specifications of software components and Simulink models of continuous processes. The integrated simulation is useful to validate the characteristics and functionalities of discrete system components early in the development process. The same logic-based specifications can also be formally verified using the Prototype Verification System (PVS), to gain additional confidence that the software design is compliant with specific safety requirements. Modeling patterns are defined for generating the logic-based specifications from the more familiar automata-based formalism. The ultimate aim of this work is to facilitate the introduction of formal verification technologies in the software development process of cyber-physical systems, which typically requires the integrated use of different formalisms and tools. A case study from the medical domain is used throughout the paper to illustrate the approach. A PVS model of a pacemaker is interfaced with a Simulink model of the human heart. The overall cyber-physical system is co-simulated to validate design requirements through exploration of relevant test scenarios. Formal verification with the PVS theorem prover is demonstrated for the pacemaker model for specific safety aspects of the pacemaker design.

Harrison MD, Masci P, Campos JC, Curzon P.  2017.  Verification of User Interface Software: the Example of Use-Related Safety Requirements and Programmable Medical Devices. IEEE Transactions on Human-Machine Systems. Abstractmedthmsv10.pdfhttps://doi.org/10.1109/THMS.2017.2717910

One part of demonstrating that a device is acceptably safe, often required by regulatory standards, is to show that it satisfies a set of requirements known to mitigate hazards. This paper is concerned with how to demonstrate that a user interface software design is compliant with use-related safety requirements. A methodology is presented based on the use of formal methods technologies to provide guidance to developers about addressing three key verification challenges: 1) how to validate a model, and show that it is a faithful representation of the device; 2) how to formalize requirements given in natural language, and demonstrate the benefits of the formalization process; and 3) how to prove requirements of a model using readily available formal verification tools. A model of a commercial device is used throughout the paper to demonstrate the methodology. A representative set of requirements are considered. They are based on US Food and Drug Administration (FDA) draft documentation for programmable medical devices, and on best practice in user interface design illustrated in relevant international standards. The methodology aims to demonstrate how to achieve the FDA’s agenda of using formal methods to support the approval process for medical devices.

Harrison M, Campos JC, Masci P.  2015.  Reusing models and properties in the analysis of similar interactive devices. Innovations in Systems and Software Engineering. 11:95-111. Abstractharros.pdf

The paper is concerned with the comparative analysis of interactive devices. It compares two devices by checking systematically a set of template properties that are designed to explore important interface characteristics. The two devices are designed to support similar tasks in a clinical setting. The devices differ as a result of judgements based on a range of considerations including software. Variations between designs are often relatively subtle and do not always become evident through even relatively thorough user testing. Notwithstanding their subtlety, these differences may be important to the safety or usability of the device. The illustrated approach uses formal techniques to provide the analysis. This means that similar analysis can be applied systematically.

Furniss D, Masci P, Curzon P, Mayer A, Blandford A.  2015.  Exploring medical device design and use through layers of Distributed Cognition: How a glucometer is coupled with its context. Journal of Biomedical Informatics. 53:330-341. Abstractexploring-medical-device-use.pdfhttps://doi.org/10.1016/j.jbi.2014.12.006

Medical devices are becoming more interconnected and complex, and are increasingly supported by fragmented organizational systems, e.g. through different processes, committees, supporting staff and training regimes. Distributed Cognition has been proposed as a framework for understanding the design and use of medical devices. However, it is not clear that it has the analytic apparatus to support the investigation of such complexities. This paper proposes a framework that introduces concentric layers to DiCoT, a method that facilitates the application of Distributed Cognition theory. We use this to explore how an inpatient blood glucose meter is coupled with its context. The analysis is based on an observational study of clinicians using a newly introduced glucometer on an oncology ward over approximately 150h (11 days and 4 nights). Using the framework we describe the basic mechanics of the system, incremental design considerations, and larger design considerations. The DiCoT concentric layers (DiCoT-CL) framework shows promise for analyzing the design and use of medical devices, and how they are coupled with their context.

Masci P, Curzon P, Furniss D, Blandford A.  2015.  Using PVS to support the analysis of distributed cognition systems. Innovations in Systems and Software Engineering. 11(2):113-130. Abstractusing-pvs-for-dc.pdfhttps://doi.org/10.1007/s11334-013-0202-2

The rigorous analysis of socio-technical systems is challenging, because people are inherent parts of the system, together with devices and artefacts. In this paper, we report on the use of PVS as a way of analysing such systems in terms of Distributed Cognition. Distributed Cognition is a conceptual framework that allows us to derive insights about plausible user trajectories in socio-technical systems by exploring what information in the environment provides resources for user action, but its application has traditionally required substantial craft skill. DiCoT adds structure and method to the analysis of socio-technical systems from a Distributed Cognition perspective. In this work, we demonstrate how PVS can be used with DiCoT to conduct a systematic analysis. We illustrate how a relatively simple use of PVS can help a field researcher (i) externalise assumptions and facts, (ii) verify the consistency of the logical argument framed in the descriptions, (iii) help uncover latent situations that may warrant further investigation, and (iv) verify conjectures about potential hazards linked to the observed use of information resources. Evidence is also provided that formal methods and empirical studies are not alternative approaches for studying a socio-technical system, but that they can complement and refine each other. The combined use of PVS and DiCoT is illustrated through a case study concerning a real-world emergency medical dispatch system.