All in all the papers of the 2005 SDL conference have been weaker than they were for the previous confer- ences. This is also due to the fact that some problems are now already solved, although (see the publicity problem) not everybody knows about the solution. This led to several papers showing the application of SDL in a straightforward way, which was not new in terms of the scientific content, but still something that was missing for SDL at large. The programme com- mittee finally decided to make up a category of short papers for those papers in order to distinguish them from “hard” research papers, but still allow them to be presented.
In general there were several papers about semantic issues, particularly two papers about MSC semantics and one about the semantics of the ‘Any()’ construct in OCL8)(which is also related to the SDL language via the select in sets). In addition, there were several papers about code generation and some papers using Petri nets. Several papers dealt with the creation and use of new languages, e.g. an access control lan- guage.
In the following is given a short review of some of the best papers of this year’s conference. The full papers can be found in [1].
ULF-Ware: An Open Framework for Integrated Tools for ITU-T Languages The ULF (Unified language family) initiative of ITU is trying to get a better integration between the related system description languages of ITU. The ULF-Ware article from Humboldt-University Berlin [2] pre- sented a specific scenario that enables such inte- gration and describes how languages have to be
5) The ITU standardised languages related to SDL are: 1) SDL for the description of systems, 2) MSC for the description of scenarios, 3) TTCN (Tree and Tabular Combined Notation) for the description of tests, 4) eODL for the description of components and deploy- ment, 5) ASN.1 (Abstract Syntax Notation ONE) for data descriptions, 6) URN (User Requirements Notation) for requirements han- dling. Finally, UML is also used to glue together these languages.
6) http://www.sdl-task-force.org/
7) MOF (Meta Object Facility) is the OMG language for the description of metamodels. It is the language that resides on top of UML and is used for the definition of UML. For technical reasons, MOF is also part of UML. It was made clear that only the MOF part of UML would be used for the integration.
described in order to be successfully combined. In particular, the research group is working on an actual environment that enables the integrated use of some of the ITU languages based on an integrated language description model.
Service Discovery and Selection using Semantic Interfaces
It has long been an unsolved problem how to use more in-depth semantic information for the selection and discovery of services. The difficult part lies in what kind of abstraction can be used to formalise the interfaces apart from simple signatures. In a joint paper from the University of Ottawa and NTNU in Trondheim [3] behaviour expressions are proposed to be used combined with goals for service selection and discovery. Although appealing at first glance, several open issues remain with this approach. In particular, the use of descriptions for goals, services and features needs a common understanding to be shared between the participants. This is an area where standardisation would be needed in the future.
UCM-Driven Testing of Web Applications This paper from the University Ottawa [4] lifts the level of abstraction of application description even higher. Starting from use case maps (UCM), test cases are developed to test web applications. This is done in two steps. Abstract test purposes are gener- ated from a UCM model using scenario definitions and scenario extraction tools. These test purposes are then converted interactively to test cases in the Fit- Nesse9)acceptance testing framework, which is pop-
ular in the Extreme Programming (XP) community10). The test cases are used to validate a Web application where several typical but non-trivial bugs were planted. Challenges in the automation of the process are also discussed.
ns+SDL – The Network Simulator for SDL Systems
In order to be able to simulate SDL specification more efficiently, a paper from University Kaisers- lautern [5] shows how to integrate the network simu- lator ns-211)with SDL. The main idea is to provide
an integration that will enable the use of the same code base for simulation and for production, such that
the task of experimenting is not a separate activity. To this end, an extension of the network simulator ns- 2 called ns+SDL was developed and tested using sev- eral protocols. The work is done using the Telelogic SDL and UML tool Telelogic Tau12).
Component development: MDA based transformation from eODL to CIDL
This is a very important paper, although from the title it is difficult to grasp its subject. It covers the most important area of component development within an MDA13)setting. eODL (extended Object Description Language) is the ITU language for specification of components; in particular their structure and inter- faces. It is a high-level language developed to work together with the other ITU languages. For use in real applications it is necessary to apply a more low-level component description language such as CIDL (Com- ponent Implementation Definition Language) defined by the Object Management Group (OMG)14)as part of the Corba Component Model15). The paper from
Humboldt-University Berlin [6] shows how Java technology Meta Data Repository (MDR) is used for this transformation. The transformation is described using transformation rules which are implemented using MOF repositories as a model storage and exe- cuted using Java.
Synthesizing State machine Behaviour from UML Collaborations and Use Case Maps Telecommunication services are provided as collabo- ration between components, which achieve the goal(s) of the service. UML 2.0 collaborations can be used to model services. Furthermore, they allow services to be described modularly and incrementally, since collaborations can be composed of subordinate collaborations. For such an approach to work, it is necessary to capture the exact dependencies between the subordinate collaborations. This paper from NTNU, Norway [7] presents the results of an experi- ment on using Use Case Maps (UCMs) for describing those dependencies, and for synthesizing the state- machine behaviour of service components from the joint information provided by the UML collabora- tions and the UCM diagrams.
9) http://fitnesse.org/
10)http://www.extremeprogramming.org/
11)ns-2 is a tool for the simulation of protocols in a network. See also http://www.isi.edu/nsnam/ns/ 12)http://www.telelogic.com/products/tau/index.cfm
13)MDA (Model Driven Architecture) is the OMG way to handle generation of systems out of high-level descriptions. 14)http://www.omg.org/
Consistency Checking of Concurrent Models for Scenario-Based Specifications Scenario-based specifications such as message sequence charts (MSC) offer an intuitive and visual way of describing design requirements. On the other hand, Petri nets can model concurrency constraints in a natural way, and are often used in modelling system specifications and designs. Since there are gaps between MSC models and Petri net models, keeping consistency between these two kinds of models is important for the success of software development. This paper from Nanjing University, China [8] con- siders the problem of checking Petri nets as models of concurrent systems against scenario-based specifica- tions expressed by message sequence charts. It pro- vides algorithms to solve the existential mandatory consistency-checking problems.