Verifying service continuity in a satellite reconfiguration procedure: application to a satellite

The paper discusses the use of the TURTLE UML profile to model and verify service continuity during dynamic reconfiguration of embedded software, and space-based telecommunication software in particular. TURTLE extends UML class diagrams with composition operators, and activity diagrams with temporal operators. Translating TURTLE to the formal description technique RT-LOTOS gives the profile a formal semantics and makes it possible to reuse verification techniques implemented by the RTL, the RT-LOTOS toolkit developed at LAAS-CNRS. The paper proposes a modeling and formal validation methodology based on TURTLE and RTL, and discusses its application to a payload software application in charge of an embedded packet switch. The paper demonstrates the benefits of using TURTLE to prove service continuity for dynamic reconfiguration of embedded software

Significantly Increasing the Usability of Model Analysis Tools through Visual Feedback

National audienceA plethora of theoretical results are available which make possible the use of dynamic analysis and model-checking for software and system models expressed in high-level modeling languages like UML, SDL or AADL. Their usage is hindered by the complexity of information processing demanded from the modeler in order to apply them and to effectively exploit their results. Our thesis is that by improving the visual presentation of the analysis results, their exploitation can be highly improved. To support this thesis, we define a trace analysis approach based on the extraction of high-level semantics events from the low-level output of a simulation or model-checking tool. This extraction offers the basis for new types of scenario visualizations, improving scenario understanding and exploration. This approach was implemented in our UML/SysML analyzer and was validated in a controlled experiment that shows a significant increase in the usability of our tool, both in terms of task performance speed and in terms of user satisfaction

Challenges and Work Directions for Europe

International audienceEmbedded Systems are components integrating software and hardware, that are jointly and specifically designed to provide a given set of functionalities. These components may be used in a huge variety of applications, including transport (avionics, space, automotive, trains), electrical and electronic appliances (cameras, toys, television, washers, dryers, audio systems, and cellular phones), process control (energy production and distribution, factory automation), telecommunications (satellites, mobile phones and telecom networks), security (e-commerce, smart cards), etc. We expect that within a short timeframe, embedded systems will be a part of virtually all equipment designed or manufactured in Europe, the USA, and Asia

Toward model-based engineering for space embedded systems and software

International audienceEmbedded systems development suffers from difficulties to reach cost, delay and safety requirements. The continuous increase of system complexity requires a corresponding increase in the capability of design fault-free systems. Model-based engineering aims to make complexity management easier with the construction of a virtual representation of systems enabling early prediction of behaviour and performance. In this context, Space industry has specific needs to deal with remote systems that can not be maintained on ground. In such systems, fault management includes complex detection, localisation and recovery automatic procedures that can not be performed without confidence on safety. In this way, only simulation and formal proofs can support the validation of all the possible configurations. Thus, formal description of both functional and non-functional properties with temporal logic formulae is expected to analyse and to early predict system characteristics at execution. This paper is based on various studies and experiences that are carried out in space domain on the support provided by model-based engineering in terms of: • support to needs capture and requirements analysis, • support to design, • support to early verification and validation, • down to automatic generation of code

Model Driven Communication Protocol Engineering and Simulation based Performance Analysis using UML 2.0

The automated functional and performance analysis of communication systems specified with some Formal Description Technique has long been the goal of telecommunication engineers. In the past SDL and Petri nets have been the most popular FDTs for the purpose. With the growth in popularity of UML the most obvious question to ask is whether one can translate one or more UML diagrams describing a system to a performance model. Until the advent of UML 2.0, that has been an impossible task since the semantics were not clear. Even though the UML semantics are still not clear for the purpose, with UML 2.0 now released and using ITU recommendation Z.109, we describe in this dissertation a methodology and tool called proSPEX (protocol Software Performance Engineering using XMI), for the design and performance analysis of communication protocols specified with UML. Our first consideration in the development of our methodology was to identify the roles of UML 2.0 diagrams in the performance modelling process. In addition, questions regarding the specification of non-functional duration contraints, or temporal aspects, were considered. We developed a semantic time model with which a lack of means of specifying communication delay and processing times in the language are addressed. Environmental characteristics such as channel bandwidth and buffer space can be specified and realistic assumptions are made regarding time and signal transfer. With proSPEX we aimed to integrate a commercial UML 2.0 model editing tool and a discrete-event simulation library. Such an approach has been advocated as being necessary in order to develop a closer integration of performance engineering with formal design and implementation methodologies. In order to realize the integration we firstly identified a suitable simulation library and then extended the library with features required to represent high-level SDL abstractions, such as extended finite state machines (EFSM) and signal addressing. In implementing proSPEX we filtered the XML output of our editor and used text templates for code generation. The filtering of the XML output and the need to extend our simulation library with EFSM abstractions was found to be significant implementation challenges. Lastly, in order to to illustrate the utility of proSPEX we conducted a performance analysis case-study in which the efficient short remote operations (ESRO) protocol is used in a wireless e-commerce scenario

Real Time System Development with UML: A Case Study

In this thesis we look at the challenges regarding VoIP and to the developer of an application providing this service. We explore CASE tools that can be used to model and verify the design of a VoIP application. VoIP applications will not be accepted by the market unless it is able to provide an audio quality comparable to traditional phones. The voice module of the application that we analyse initially did not meet these requirements. We investigate how the design and implementation must be altered to meet them. Although UML in its current specification is not adapted to the design of real-time applications, CASE tools exist that propose an extension of UML for this purpose. We investigate two of these - Rational Rose RT and Telelogic Tau - for their usefulness in re-engineering the application. We show their support partially covers our needs and we present novel UML concepts that would have been useful in resolving our task. We further demonstrate important new concepts of UML 2.0

ASSESSMENT OF MODEL CONVERSION FROM GENESYS TO MAGIC SYSTEM OF SYSTEMS ARCHITECT FOR MODEL-BASED SYSTEMS ENGINEERING INTEROPERABILITY

This thesis investigates whether the information contained in a Vitech Genesys model can retain its informational accuracy after conversion into a Dassault Systemes’ Magic System of Systems Architect (MSOSA) model. The thesis uses a sample system model in Vitech that implements the system definition language (SDL) and converts it to MSOSA, which uses the systems modeling language (SysML). The study reviewed conversion methods available to the user and converted a Genesys model to an MSOSA model using the only available method, Excel. The study then assessed the converted model and outlined any post-migration remediation. The results of this thesis demonstrate that the currently available methods are feasible but inefficient, as only 34% of the entities and 9% of the relationships transferred successfully during the experiment. Genesys can output tabular data that represents system model entities and relationships; however, the MSOSA import function was unable to correctly import entities that had one-to-many relationships with other entities. Consequently, the user must perform manual manipulation during the conversion process. Furthermore, ontological differences between the tools prevented the complete import of behavioral data, since many SDL entities map to more than one SysML entity. Based on the results, this thesis recommends pursuing an extensible markup language–based software solution for Genesys and MSOSA and developing a formal Navy and Marine Corps ontology.Civilian, Department of the NavyApproved for public release. Distribution is unlimited