This volume contains the papers presented at the 12th SDL Forum, Grimstad, Norway. The SDL Forum was ?rst held in 1982, and then every two years from 1985. Initially the Forum was concerned only with the Speci?cation and Description Language that was ?rst standardized in the 1976 Orange Book of the Inter- tional Telecommunication Union (ITU). Since then, many developments took place and the language has undergone several changes. However, the main underlying paradigm has survived, and it is the reason for the success of the Speci?cation and Description Language in many projects. This paradigm is based on the following important principles of distributed - plications: Communication: large systems tend to be described using smaller parts that communicate with each other; State: the systems are described on the basis of an explicit notion of state; State change: the behavior of the system is described in terms of (local) changes of the state. The original language is not the only representative for this kind of paradigm, so the scope of the SDL Forum was extended quite soon after the ?rst few events to also include other ITU standardized languages of the same family, such as MSC, ASN.1 and TTCN. This led to the current scope of System Design Languages coveringallstagesofthedevelopmentprocessincludinginparticularSDL,MSC, UML, ASN.1, eODL, TTCN, and URN. The focus is clearly on the advantages to users, and how to get from these languages the same advantage given by the ITU Speci?cation and Description Language: code generation from high-level speci?cations.

This volume contains the papers presented at the 12th SDL Forum, Grimstad, Norway. The SDL Forum was ?rst held in 1982, and then every two years from 1985. Initially the Forum was concerned only with the Speci?cation and Description Language that was ?rst standardized in the 1976 Orange Book of the Inter- tional Telecommunication Union (ITU). Since then, many developments took place and the language has undergone several changes. However, the main underlying paradigm has survived, and it is the reason for the success of the Speci?cation and Description Language in many projects. This paradigm is based on the following important principles of distributed - plications: Communication: large systems tend to be described using smaller parts that communicate with each other; State: the systems are described on the basis of an explicit notion of state; State change: the behavior of the system is described in terms of (local) changes of the state. The original language is not the only representative for this kind of paradigm, so the scope of the SDL Forum was extended quite soon after the ?rst few events to also include other ITU standardized languages of the same family, such as MSC, ASN.1 and TTCN. This led to the current scope of System Design Languages coveringallstagesofthedevelopmentprocessincludinginparticularSDL,MSC, UML, ASN.1, eODL, TTCN, and URN. The focus is clearly on the advantages to users, and how to get from these languages the same advantage given by the ITU Speci?cation and Description Language: code generation from high-level speci?cations.

This volume contains the papers presented at the 11th SDL Forum, Stuttgart. As well as the papers, the 11th SDL Forum also hosted a system design competition sponsored by Solinet with a cash prize for the “best” design. This follows a similar competition at the SAM 2002 workshop (papers published in LNCS 2599). The winning entry from SAM 2002 is described in the last paper in this volume. The SDL Forum was ?rst held in 1982, and then every two years from 1985. Initially the Forum was concerned only with the Speci?cation and Descr- tion Language ?rst standardized in the 1976 Orange Book of the International Telecommunication Union (ITU). From the start this graphical CEFSM (communicating extended ?nite state machines) notation was used both to describe the implementation of systems and to specify systems (especially protocol systems in standards). In the early days both types of description were quite informal, though speci?cations were certainly more formal than the main alternative: natural languagewith some ad hoc ?gures. Implementations were usually written in assembly language, which is at too low a level to reason well about the interaction between communic- ing agents within a system. In this case the notation provided an intermediate description that gave an overview of how the implementation worked, and often the actual logical development was done at the graphical level with hand coding of that description.

This volume contains the papers presented at the Tenth SDL Forum, Cop- hagen. SDL is the Speci?cation and Description Language ?rst standardized by the world telecommunications body, the International Telecommunications Union (ITU), more than 20 years ago in 1976. While the original language and domain of application has evolved signi?cantly, the foundations of SDL as a graphical, state-transition and process-communication language for real-time systems have remained. Today SDL has also grown to be one notation in the set of uni?ed modelling languages recommended by the ITU (ASN.1, MSC, SDL, ODL, and TTCN) that can be used in methodology taking engineering of systems from requirements capture through to testing and operation. The SDL Forum is held every two years and has become the most imp- tant event in the calendar for anyone involved in SDL and related languages and technology. The SDL Forum Society that runs the Forum is a non-pro?t organization whose aim it is to promote and develop these languages.

This volume contains the papers presented at the 11th SDL Forum, Stuttgart. As well as the papers, the 11th SDL Forum also hosted a system design competition sponsored by Solinet with a cash prize for the “best” design. This follows a similar competition at the SAM 2002 workshop (papers published in LNCS 2599). The winning entry from SAM 2002 is described in the last paper in this volume. The SDL Forum was ?rst held in 1982, and then every two years from 1985. Initially the Forum was concerned only with the Speci?cation and Descr- tion Language ?rst standardized in the 1976 Orange Book of the International Telecommunication Union (ITU). From the start this graphical CEFSM (communicating extended ?nite state machines) notation was used both to describe the implementation of systems and to specify systems (especially protocol systems in standards). In the early days both types of description were quite informal, though speci?cations were certainly more formal than the main alternative: natural languagewith some ad hoc ?gures. Implementations were usually written in assembly language, which is at too low a level to reason well about the interaction between communic- ing agents within a system. In this case the notation provided an intermediate description that gave an overview of how the implementation worked, and often the actual logical development was done at the graphical level with hand coding of that description.

This volume contains the papers presented at the Tenth SDL Forum, Cop- hagen. SDL is the Speci?cation and Description Language ?rst standardized by the world telecommunications body, the International Telecommunications Union (ITU), more than 20 years ago in 1976. While the original language and domain of application has evolved signi?cantly, the foundations of SDL as a graphical, state-transition and process-communication language for real-time systems have remained. Today SDL has also grown to be one notation in the set of uni?ed modelling languages recommended by the ITU (ASN.1, MSC, SDL, ODL, and TTCN) that can be used in methodology taking engineering of systems from requirements capture through to testing and operation. The SDL Forum is held every two years and has become the most imp- tant event in the calendar for anyone involved in SDL and related languages and technology. The SDL Forum Society that runs the Forum is a non-pro?t organization whose aim it is to promote and develop these languages.

This volume contains the papers presented at the 12th SDL Forum, Grimstad, Norway. The SDL Forum was ?rst held in 1982, and then every two years from 1985. Initially the Forum was concerned only with the Speci?cation and Description Language that was ?rst standardized in the 1976 Orange Book of the Inter- tional Telecommunication Union (ITU). Since then, many developments took place and the language has undergone several changes. However, the main underlying paradigm has survived, and it is the reason for the success of the Speci?cation and Description Language in many projects. This paradigm is based on the following important principles of distributed - plications: Communication: large systems tend to be described using smaller parts that communicate with each other; State: the systems are described on the basis of an explicit notion of state; State change: the behavior of the system is described in terms of (local) changes of the state. The original language is not the only representative for this kind of paradigm, so the scope of the SDL Forum was extended quite soon after the ?rst few events to also include other ITU standardized languages of the same family, such as MSC, ASN.1 and TTCN. This led to the current scope of System Design Languages coveringallstagesofthedevelopmentprocessincludinginparticularSDL,MSC, UML, ASN.1, eODL, TTCN, and URN. The focus is clearly on the advantages to users, and how to get from these languages the same advantage given by the ITU Speci?cation and Description Language: code generation from high-level speci?cations.

This volume contains the papers presented at the 12th SDL Forum, Grimstad, Norway. The SDL Forum was ?rst held in 1982, and then every two years from 1985. Initially the Forum was concerned only with the Speci?cation and Description Language that was ?rst standardized in the 1976 Orange Book of the Inter- tional Telecommunication Union (ITU). Since then, many developments took place and the language has undergone several changes. However, the main underlying paradigm has survived, and it is the reason for the success of the Speci?cation and Description Language in many projects. This paradigm is based on the following important principles of distributed - plications: Communication: large systems tend to be described using smaller parts that communicate with each other; State: the systems are described on the basis of an explicit notion of state; State change: the behavior of the system is described in terms of (local) changes of the state. The original language is not the only representative for this kind of paradigm, so the scope of the SDL Forum was extended quite soon after the ?rst few events to also include other ITU standardized languages of the same family, such as MSC, ASN.1 and TTCN. This led to the current scope of System Design Languages coveringallstagesofthedevelopmentprocessincludinginparticularSDL,MSC, UML, ASN.1, eODL, TTCN, and URN. The focus is clearly on the advantages to users, and how to get from these languages the same advantage given by the ITU Speci?cation and Description Language: code generation from high-level speci?cations.

This volume contains the papers presented at the 11th SDL Forum, Stuttgart. As well as the papers, the 11th SDL Forum also hosted a system design competition sponsored by Solinet with a cash prize for the “best” design. This follows a similar competition at the SAM 2002 workshop (papers published in LNCS 2599). The winning entry from SAM 2002 is described in the last paper in this volume. The SDL Forum was ?rst held in 1982, and then every two years from 1985. Initially the Forum was concerned only with the Speci?cation and Descr- tion Language ?rst standardized in the 1976 Orange Book of the International Telecommunication Union (ITU). From the start this graphical CEFSM (communicating extended ?nite state machines) notation was used both to describe the implementation of systems and to specify systems (especially protocol systems in standards). In the early days both types of description were quite informal, though speci?cations were certainly more formal than the main alternative: natural languagewith some ad hoc ?gures. Implementations were usually written in assembly language, which is at too low a level to reason well about the interaction between communic- ing agents within a system. In this case the notation provided an intermediate description that gave an overview of how the implementation worked, and often the actual logical development was done at the graphical level with hand coding of that description.

This volume contains the papers presented at the Tenth SDL Forum, Cop- hagen. SDL is the Speci?cation and Description Language ?rst standardized by the world telecommunications body, the International Telecommunications Union (ITU), more than 20 years ago in 1976. While the original language and domain of application has evolved signi?cantly, the foundations of SDL as a graphical, state-transition and process-communication language for real-time systems have remained. Today SDL has also grown to be one notation in the set of uni?ed modelling languages recommended by the ITU (ASN.1, MSC, SDL, ODL, and TTCN) that can be used in methodology taking engineering of systems from requirements capture through to testing and operation. The SDL Forum is held every two years and has become the most imp- tant event in the calendar for anyone involved in SDL and related languages and technology. The SDL Forum Society that runs the Forum is a non-pro?t organization whose aim it is to promote and develop these languages.

This volume contains the papers presented at the 11th SDL Forum, Stuttgart. As well as the papers, the 11th SDL Forum also hosted a system design competition sponsored by Solinet with a cash prize for the “best” design. This follows a similar competition at the SAM 2002 workshop (papers published in LNCS 2599). The winning entry from SAM 2002 is described in the last paper in this volume. The SDL Forum was ?rst held in 1982, and then every two years from 1985. Initially the Forum was concerned only with the Speci?cation and Descr- tion Language ?rst standardized in the 1976 Orange Book of the International Telecommunication Union (ITU). From the start this graphical CEFSM (communicating extended ?nite state machines) notation was used both to describe the implementation of systems and to specify systems (especially protocol systems in standards). In the early days both types of description were quite informal, though speci?cations were certainly more formal than the main alternative: natural languagewith some ad hoc ?gures. Implementations were usually written in assembly language, which is at too low a level to reason well about the interaction between communic- ing agents within a system. In this case the notation provided an intermediate description that gave an overview of how the implementation worked, and often the actual logical development was done at the graphical level with hand coding of that description.

This volume contains the papers presented at the Tenth SDL Forum, Cop- hagen. SDL is the Speci?cation and Description Language ?rst standardized by the world telecommunications body, the International Telecommunications Union (ITU), more than 20 years ago in 1976. While the original language and domain of application has evolved signi?cantly, the foundations of SDL as a graphical, state-transition and process-communication language for real-time systems have remained. Today SDL has also grown to be one notation in the set of uni?ed modelling languages recommended by the ITU (ASN.1, MSC, SDL, ODL, and TTCN) that can be used in methodology taking engineering of systems from requirements capture through to testing and operation. The SDL Forum is held every two years and has become the most imp- tant event in the calendar for anyone involved in SDL and related languages and technology. The SDL Forum Society that runs the Forum is a non-pro?t organization whose aim it is to promote and develop these languages.