TURTLE-P: a UML profile for the formal validation of critical and distributed systems

The timed UML and RT-LOTOS environment, or TURTLE for short, extends UML class and activity diagrams with composition and temporal operators. TURTLE is a real-time UML profile with a formal semantics expressed in RT-LOTOS. Further, it is supported by a formal validation toolkit. This paper introduces TURTLE-P, an extended profile no longer restricted to the abstract modeling of distributed systems. Indeed, TURTLE-P addresses the concrete descriptions of communication architectures, including quality of service parameters (delay, jitter, etc.). This new profile enables co-design of hardware and software components with extended UML component and deployment diagrams. Properties of these diagrams can be evaluated and/or validated thanks to the formal semantics given in RT-LOTOS. The application of TURTLE-P is illustrated with a telecommunication satellite system

A Semantics for Timed MSC

AbstractMessage Sequence Charts (MSC) is a graphical and textual specification language developed by ITU-T. It is widely used in telecommunication software engineering for specifying behavioral scenarios. Recently, the time concept has been introduced into MSC'2000. To support the specification and verification of real-time systems using timed MSC, we need to define its formal semantics. In this paper, we use timed lposet as a semantic model and give a formal semantics for timed MSC. We first define an event in a timed MSC as a timed lposet, then give a formal semantics for timed basic MSCs, timed MSCs with structures and high-level MSCs. In this paper, we also discuss some important issues related to timed MSC

Differentiated QoS for overlay-based disaster response systems

Disaster response systems (DRSs) assist responders by providing a wide range of services. These services are usually implemented as distributed applications (overlays) capable of operating in an infrastructure-less underlying network such as MANETs. However, all the services in DRSs may not be equally critical. For instance, the communication between firefighters is certainly more important than the communication between news reporters. Ensuring the reliability and the quality of the required vital services is a key to successful disaster response operations. We propose a differentiated QoS architecture for overlay-based DRSs to enforce a prioritization scheme between overlays as well as between users within overlays. Our architecture provides self-organizing distributed admission control and policy enforcement services. We have run extensive simulations to evaluate the performance of our architecture. The results show that our architecture not only enables differentiated QoS, it also improves overall QoS in terms of the number of successful overlay flows. © 2014 IEEE

Comparison of SPIN and VIS for protocol verification

In this paper, we compare and contrast SPIN and VIS, two widely used formal verification tools. In particular, we devote special attention to the efficiency of these tools for the verification of communications protocols that can be implemented either in software or hardware. As a basis of our comparison, we formally describe and verify the Asynchronous Transfer Mode Ring (ATMR) medium access protocol using SPIN and its hardware model using VIS. We believe that this study is of particular interest as more and more protocols, like ATM protocols, are implemented in hardware to match high-speed requirements

UML Profiles for Real-Time Systems and their Applications

Real-time systems (RTS) have strict timing constraints and limited resources. The satisfaction of RTS timing constraints is required for their correction. In order to reduce the cost due to late discovery of design flaws and/or violations of timing constraints of RTS as well as to speed up their development to cope with time-to-market requirements, it is important to validate, at early stages of the development process, the functional and nonfunctional properties of RTS. In addition, RTS complexity is continuously increasing which makes their design very challenging. UML, a graphical object-oriented modeling language, is suitable to deal with this complexity. UML also supports predictive, quantitative analysis through its real-time profiles. The objective of this paper is to review the most important UML profiles for real-time from the academia, the industry and/or standard organizations; and the research activity that revolves around these profiles

Merging Behavior Specifications

This paper describes a method for merging behavior specifications modeled by transition systems. Given two behavior specifications B1 and B2, Merge(B1, B2) defines a new behavior specification that extends B1 and B2. Moreover, provided that a necessary and sufficient condition holds, Merge(B1, B2) is a cyclic extension of B1 and B2. In other words, Merge(B1, B2) extends B1 and B2, and any cyclic trace in B1 or B2 remains a cyclic in Merge(B1, B2). Therefore, in the case of cyclic traces of B1 or B2, Merge(B1, B2) transforms into Merge(B1, B2), and may exhibit, in a recursive manner, behaviors of B1 and B2. If Merge(B1, B2) is a cyclic extension of B1 and B2, then Merge(B1, B2) represents the least common cyclic extension of B1 and B2. This approach is useful for the extension and integration of system specifications. 1 Introduction Formal specifications play an important role in the development life cycle of systems. They capture the user requirements. They can be validated against suc..