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This paper presents a UML 2 profile for communicating systems. It is driven by the experience of SDL and uses formal constraints for profile definition and mapping rules by means of OCL. It features language elements for high-level specification and description of Internet communication and signaling protocols where SDL is not optimally suited. Due to its support of several concrete notations, this profile is aligned to work with several UML 2 compliant modeling tools. In addition, an implementation by an XSLT-based mapping from UML to behavioral and structural SDL specifications is available. The intention of the paper is to present the main work done which is defining an actual profile and mapping this to SDL.

eODL is the ITU component description language. Its current status is that it is defined textually and there are several transformations into other languages. There are also ideas about a graphical representation for eODL. In this article we present a graphical representation for some of the eODL language elements and discuss how such a graphical representation can be implemented using a high-level formal description language in comparison with a UML profile.

Distributed real-time systems call for expressive modeling languages to capture and express their functional and nonfunctional requirements at early stages of the development process. The UML profile for Schedulability, Performance and Time (UML/SPT) is an object-oriented real-time modeling language. UML/SPT has been designed using the built-in extension mechanisms of UML, which makes it flexible and customizable. In this paper, we propose an extension for UML/SPT to capture multicast communications. We define a metamodel that encapsulates the main concepts involved in multicast communications, we show its relationship to UML/SPT domain model, and we introduce new stereotypes corresponding to these concepts. We illustrate the extension with the modeling of the Reliable Multicast Transport Protocol (RMTP2). Finally, we compare our approach to extend UML/SPT for multicast communications with an extension for MSC having the same purpose.

Expressive system modelling languages lead to language definitions that are long and hard to understand. Tool support for these languages is hard to implement, and often only parts of the language are supported. In this paper we introduce the concept of language profiles as well-defined subsets of a language with formal syntax and semantics as the basis for tool support. We outline two approaches to generate language profiles for SDL from the complete formal semantics definition, and provide a formalisation for a reduction-based approach, on which a tool for this approach is based.

The design of distributed systems requirements often ends with a collection of redundant use cases or scenarios, each of which illustrating a peculiar functionality or a typical execution of the system. The actual behavior of the system under design can be considered as a superposition of all use cases. However, current scenario languages do not propose such superposition mechanism. An operator for Message Sequence Charts defined as a sum of MSCs was proposed recently. However, the designer must provide explicitly the common parts in operands (called the interface) to compute a sum. This paper proposes an automatic construction of this interface based on a heuristic search.

Existing notations for expressing time constraints in high-level message sequence charts (HMSC) may cause ambiguity when used with HMSC compositions such as alternative and iteration. To overcome such limitation, we propose (THMSC) which include an unambiguous subset of time constraints and timed edges as a new complementary notation. THMSC is effective in accurately specifying popular requirement patterns such as watchdog timers and periodic tasks. We present the formal semantics and demonstrate the effectiveness of THMSC using a real-world example that formalizes timing requirements for Korea Multi-Purpose Satellite (KOMPSAT) software.

Scenario-driven requirement specifications are widely used to capture and represent functional requirements. Use Case Maps are being standardized as part of the User Requirements Notation (URN), the most recent addition to ITU-T’s family of languages. UCM models focus on the description of functional requirements and high-level designs at early stages of the development process. How a system is executed over time and how this may affect its correctness and performance, however, are introduced later in the development process which may require considerable changes in design or even worse at the requirement analysis level. We believe that timing aspects must be integrated into the system model, and this must be done already at an early stage of development. This paper introduces an approach to describe timing constraints in Use Case Maps specifications. We present a formal semantics of Timed UCM in terms of Clocked Transition Systems (CTS). We illustrate our approach using an example of a simplified wireless system.

We use SDL and UML 2.0 state machines for behavior modeling of communication control software for telecommunication services. To ensure consistent designs we want to identify when a signal sent is not consumed and when a state machine waits indefinitely for a signal that never arrives. One approach to ensure such consistency is to derive interface contracts for each port from the properties of the state machine and use the contracts to check consistency. In this paper we describe how Calculus for Communicating Systems (CCS) [1] and stuck-free conformance [2] can be used as a formal fundament for this consistency checking. Interface descriptions should be comprehensible without having to learn process algebra. Therefore we introduce a graphical notation for both the port contracts and for the interaction made possible across the interface of two state machines.

To produce accurate performance assessments of SDL models by simulation, all resources influencing system performance must be simulated together. Existing performance simulators usually support the simulation of a single resource only. One way to achieve support of multiple resources is the extension of existing simulators. In this paper, we present a different solution that can be realized with a relatively small effort. The core of the solution is a simulator interconnection framework for the performance simulation of SDL models. With this framework, existing simulators for different resources can be integrated. We show how the framework has been used to integrate (network simulation), Avrora (hardware simulation), and a simulator extension for SDL models. Several performance simulations of a Mica network scenario provide evidence for the additional accuracy achieved with the integrated simulator.

Experience with the development and maintenance of test suites has shown that the (TTCN-3) provides very good concepts for adequate test specification. However, experience has also demonstrated that during either the migration of legacy test suites to TTCN-3, or the development of large TTCN-3 test specifications, users have found it is difficult to construct TTCN-3 tests that are concise with respect to readability, usability, and maintainability. To address these issues, this paper investigates refactoring and metrics for TTCN-3. Refactoring restructures a test suite systematically without changing its behaviour. Complementary metrics are used to assess the quality of TTCN-3 test suites. For automation, a tool called TRex has been developed that supports refactoring and metrics for TTCN-3.