  Nowadays computing becomes increasingly mobile and pervasive. One of the
important steps in pervasive computing is context-awareness. Context-aware
pervasive systems rely on information about the context and user preferences to
adapt their behavior. However, context-aware applications do not always behave
as user's desire, and can cause users to feel dissatisfied with unexpected
actions. To solve these problems, context-aware systems must provide mechanisms
to adapt automatically when the context changes significantly. The interesting
characteristic of context is its own behaviors which depend on various aspects
of the surrounding contexts. This paper uses contextual graphs to solve the
problem "the mutual relationships among the contexts". We describe the most
relevant work in this area, as well as ongoing research on developing
context-aware system for ubiquitous computing based on contextual graph. The
usage of contextual graph in context-awareness is expected to make it effective
for developers to develop various applications with the need of context
reasoning.
