This book constitutes the refereed proceedings of the 9th International Conference on Model Driven Engineering Languages and Systems (formerly UML conferences), MoDELS 2006. The book presents 51 revised full papers and 2 invited papers. Discussion is organized in topical sections on evaluating UML, MDA in software development, concrete syntax, applying UML to interaction and coordination, aspects, model integration, formal semantics of UML, security, model transformation tools and implementation, and more.

Component-based software development is the next step after object-oriented programmingthatpromisesto reducecomplexityandimprovereusability.These advantages have also been identi?ed by the industry, and consequently, over the past years, a large number of component-based techniques and processes have been adopted in many of these organizations. A visible result of this is the number ofcomponentmodels thathavebeendevelopedandstandardized.These models de?ne how individual software components interact with each other and simplify the design process of software systems by allowing developers to choose from previously existing components. The development of component models is a ?rst step in the right direction, but there are many challenges that cannot be solved by the development of a new component model alone. Such challengesare the adaptation of components, and their development and veri?cation. Software Composition is the premiere workshop to advance the research in component-based software engineering and its related ?elds. SC 2005 was the fourth workshop in this series. As in previous years, SC 2005 was organized as an event co-located with the ETAPS conference. This year s program consisted of a keynote on the revival of dynamic l- guages given by Prof. Oscar Nierstrasz and 13 technical paper presentations (9 full and 4 short papers). The technical papers were carefully selected from a total of 41 submitted papers. Each paper was thoroughly peer reviewed by at leastthreemembers oftheprogramcommittee andconsensusonacceptancewas achieved by means of an electronic PC discussion. This LNCS volume contains the revised versions of the papers presented at SC 2005."

Interest has grown rapidly over the past dozen years in the application of object-oriented programming and methods to the development of distributed, open systems. This volume presents the proceedings of a workshop intended to assess the current state of research in this field and to facilitate interaction between groups working on very different aspects of object-oriented distributed systems. The workshop was held as part of the 1993 European Conference on Object-Oriented Programming (ECOOP '93). Over fifty people submitted position papers and participated in the workshop, and almost half presented papers. The presented papers were carefully reviewed and revised after the workshop, and 14 papers were selected for this volume.

The ECOOP '91 Workshop on Object-Based Concurrent Computing was organized toprovide a forum on concurrent, distributed and open-ended computing. The emphasis was on conceptual, theoretical and formal aspects, as well as practical aspects and sound experience, since such a viewpoint was deemed indispensible to investigate and establish a basis for future development. This volume contains 12 papers selected from 25 presented at the workshop, together with a paper by J.A. Goguen, who was an invited speaker at the workshop. The papers are classified into four categories: Formal methods (1): three papers are concerned with the formal semantics of concurrent objects based on process calculi. Formal methods (2): four papers are concerned with various formal approaches to the semantics of concurrent programs. Concurrent programming: three papers. Models: three papers areconcerned with models for concurrent systems.