The field of ubiquitous computing has recently proliferated with a view to providing applications and services that are able to adapt to the rapidly changing situations in dynamic environments and act accordingly. The seamless adaptation to contexts and the alterations to behaviour require the applications to implement mechanisms for acquiring the context information. The required context information is usually diverse and scattered throughout the environment. On account of this, the processing of the context information and its compilation from separate sources is a requirement for the applications to reach adequate context-awareness for successful adaptation. To facilitate the development of context-aware applications, service-oriented architectures for supporting the context-awareness have emerged. In this work the research problem was to find a solution for dynamic acquisition and representation of distributed context information and its efficient provisioning for ubiquitous applications. As a solution to the research problem this work provides a service architecture called Context Monitoring Service (CMS), which utilizes a dynamically evolving semantic model of context information that the applications can access. A requirement analysis for such architecture was carried out by a literature review in the field of context-awareness. The architecture of the CMS was designed according to the identified requirements and a prototype implementation was created for validation purposes. The prototype implementation successfully validated the architecture's functionality and also opened issues for future research and development in this field.