synonymes rencontrer des difficults In a moving world where the customer requirements, marketplace organisation and technologies change continuously dynamic adaptation becomes essential. Coupled to the market globalisation, these structural changes increase the need to develop virtual companies, alliances and partnerships in a “globalized” world force. In such configuration, enterprises have to analyse their value chains to detect their core of processes and define adapted collaborative strategies. Once the company detects its key processes several problems must be solved : (1) How can we organise (transversal due to their collaborative nature) processes management, i.e. how can we balance power relationships between such transversal process owners and “vertical” business unit managers, how can we define consistent individual objectives, how can we motivate both staff and managers to improve simultaneously their “vertical” performance level and their horizontal solidarity. • As organization, technologies and human aspects (competences, culture…) are structurally interacting with the process organisation and execution, we have to bring consistency towards these different aspects and the process frame to get a global improvement. (2) As far as the company organization is concerned, this process orientation involves redefining the organisation thanks to goals, identifying the processes to achieve and then determining for each process the required competencies and means. Without being constrained by the corporate organisation. (3) In order to initialize a dynamic and ever changing collaborative processes the security concerns should be integrated in the process definition from the basic process component in the one hand and should be guaranteed in the global process in the other hand in such a way to assure the compliance of the local as well as global security issues and requirements, thus a cross level security framework should be thought to meet these needs. The objective of this PhD thesis will be to propose a new strategy of urbanization including : (a) Introduce a modelling architecture based on the business process and define the related model constructs which allow to represent and lead the changing processes, simultaneously, in the information system and in the organization of the company and which highlights the flexibility of the organization depending on the concept of the decoupling between the processes and their organisational and technical environment. The company model resulted from such architecture of modelling must be a complete model which integrates various dimensions of collaboration : technical dimension (coordination, infrastructure), operational dimension (generic, virtual and real process) and contractual dimension. (b) Propose and describe an infrastructure of information system according to the SOA paradigm and determine the validation rules which allow a dynamic composition of services, and the integration of various dimensions (human, resources, machines. .etc.) in the interface of services, as well as define a mechanism of real time events flows treatment to allow the transformation of passive business processes into reactive processes based on real time information even into proactive business processes. (c) Integrate security requirements in this service architecture, focusing on the following points : (i) Defining security requirements due to both the security policy specification, to the execution context (by taking into account specific risks due to the pervasive service environment) and to the user preferences. (ii) Defining how security requirements can be integrated in business process models and the way they could be associated to services. (iii) Specification of and integrate these requirements in service context and in user preferences. (iv) Definition of “security patterns” that could guide service composition.