Advances in networking, sensors, medical devices and smart phones have made it feasible to monitor and provide medical and other assistance to people either in their homes or outside. Aging populations will benefit from reduced costs and improved healthcare through assisted living based on these technologies. However, these systems challenge current state-of-the-art techniques for usability, reliability, and security. In this paper we present the PAS open architecture for assisted living, which allows independently developed third party components to collaborate. Furthermore, we incorporate cell phones in PAS as the local intelligence in order to enhance the robustness and ubiquity. We discuss key technological issues in assisted living systems, such as software architecture layout, power preserving, security and privacy; and results from our pilot study in a real assisted living facility are presented.

The main focus of current research in trusted operating systems (TOS) is on the enhanced access control of reference monitors which, in turn, control the individual operations on a given access instance. However, many real-life runtime attacks involve behavioral semantics. We have proposed an extended reference monitor to support both access and behavior controls. This results in a sequence of operations which are also of concern in security enforcement. This paper presents a policy language for the extended reference monitor. Our policy language is based on domain and type enforcement (DTE) and role-based access control (RBAC). Permission is defined as an event and a state of behavior is represented as a fluent to be accorded with the convention of event calculus (EC). Behavior policies can be expressed with the EC style syntax as well as access control policies

Advances in networking, sensors, and embedded devices have made it feasible to monitor and provide medical and other assistance to people in their homes. Aging populations will benefit from reduced costs and improved healthcare through assisted living based on these technologies. However, these systems challenge current state-of-the-art techniques for usability, reliability, and security. This is a particular challenge for open and extensible systems that combine software and hardware from many vendors and provide information to diverse clinicians. In this paper we present the I-Living architecture for assisted living that allows independent parties work together in a dependable, secure, and low-cost fashion with predictable properties. Our approach is based on an Assisted Living Service Provider (ALSP) who provides a server that collects and maintains encrypted assisted persons (APs)' records. Our ALSP can be a third party distinct from APs, communication providers, and clinicians; or it can be part of an ISP, hospital or similar enterprise. We have explored the architecture by developing a collection of applications and implementing them in a prototype system. Our system shows the feasibility and opportunity of an open approach to assisted living systems.

To design and develop secure operating systems, the BLP (Bell-La Padula) model has been widely adopted. However user's security label in the most developed systems based on the BLP model is inherited to a process that is actual subject on behalf of the user, regardless whatever the process behavior is. So, there could be information disclosure threat or modification threat by malicious or unreliable processes even though the user is authorized in the system. These problems can be solved by defining the subject as (user process) ordered pair and by defining the process reliability. This paper presents an extended BLP (E-BLP) model in which processes are grouped into two subdivisions, common and public, and the execution of a process is controlled by DRC (Dynamic Reliability Check) to prevent the malicious behavior of the process. Therefore, this model mitigates the confidentiality threat, integrity threat, and also gives enhanced usability of the system.