| Pervasive computing systems provide personalized and intimate services to improve the quality of life by offering seamlessly integrated computation and communication at users' disposal. Since they have the capability to interact with the physical world and are designed to assist or manage aspects of users' daily lives, the requirement for certain level of safety guarantee is high and imminent.;Enhancing safety proves to be challenging because of the inherent dynamicity, complexity, heterogeneity and uncertainty typical in the pervasive computing environment. These attributes make applying a single external overarching mechanism to enforce safety measures infeasible. The better solution is to incorporate safety-aware software practice and enforcement mechanisms at the design and implementation phases, and a bottom-up approach to ensure the safety of each component as well as the interactions between them. It allows elimination of some safety risks before they are deployed, and monitors and handles others at runtime.;A system analysis is performed to identify the four fundamental elements of any pervasive computing system, and to establish a formal model for each of these elements. A risk analysis follows, which outlines the potential safety hazards resulting from the system design and implementation flaws, and uncontrollable factors such as natural disasters and human errors. Based on the findings from these analyses, a safety mechanism is designed and implemented to reduce, detect and handle various risks.;To seek a more natural and effective solution, we explore an alternative programming model focusing on context at its core. It allows for powerful yet easy detections of conflicts, dangerous situations and illogical goals or actions. It is entirely user-centric, and allows programmers and users to grasp the complete status of the space. Furthermore, a programming procedure with linear complexity is established and the automatic optimal action plan evaluation process is devised.;Safety concern is one of the major hurdles preventing pervasive systems from being widely adopted, we believe the proposed enhancements in safety and reliability can go a long way in earning the trust of general public on this emerging technology. |
