Challenges in pure ubiquitous computing, including the limitation of being multi-domain, absence of a uniform namespace, impossible intensive mobility of users, limited resources, lack of scalability, intensive applications, and so forth, have led researchers to provide hybrid ubiquitous architectures that are generally cloud-based. However, various types of services have not been considered in the introduced hybrid architectures nor have any of these architectures provided a general categorization of services independent of application type. The current paper introduces a cloud-based ubiquitous architecture called as CLOUBI. The main purpose of this architecture is to remove restrictions on pure ubiquitous architectures. In addition, two general categories of services are presented in this architecture, of which one is based on the nature of services and the other on the distance between the requesting and responding entities, with both being independent of application type. In the nature-based categorization, services are divided into four types: data, context-aware, software, and hardware. In the distancebased categorization, services are of five types: near, local, remote, global, and far. In order to design CLOUBI architecture and formulate its proposed categorization, various criteria are examined, including the types of inputs, nature of requests, characteristics of an ideal ubiquitous architecture, and features expected from the services in hybrid architectures. In addition, the most important security concerns related to ubiquitous cloud computing architectures are discussed.

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