An effective model and management scheme of personal space for ubiquitous computing applications

In ubiquitous computing, the computing environment for a user is no longer a fixed computer, but a space that includes multiple heterogeneous devices that can change dynamically according to the user's situation. Managing the space is an essential part of ubiquitous computing because application services in this environment need to be adaptive to the users' current situation. However, previous approaches oversimplified the model of personal space and demonstrated some limitations in developing user-centric adaptive services. In this paper, we propose an effective personal space model, defined as virtual personal world (VPW), and a sophisticated method to manage personal spaces. The VPW represents a personal space by using a set of stateful elements and their relationships, which are denoted as virtual objects, services, and neighbors. The VPW provides expressive and accurate information for a particular user, thereby helping application services adapt their operations for the user dynamically. Our conceptual model is designed as personal operating middleware software that manages the user's VPW and provides application services. Experimental results show that the prototype system based on VPW has reasonable performance in running application services and managing personal spaces. We also found that the VPW model can increase the average user satisfaction rate by up to 40% compared to other models in our simulation environment.