A Type System for Checking Consistencies of a Policy Specification Used in Ubiquitous Programming Environment

The high-level policy description language used for ubiquitous programming framework specifies context entity relations, as well as context-based access control and adaptation rules. Then the specification in the policy description language is translated into the code in a general-purpose language, which is to be used in ubiquitous environment. However, the inconsistencies and errors in the policy specification are all passed into the translated code, potentially resulting disastrous malfunction. This paper introduces a type system that checks the consistency of a policy specification so that the specification is free from type-related errors and inconsistencies.