With the increasing advances in medical, computing and networking technologies, we can significantly improve the quality and safety of medical device networks. In hospitals and clinics, these networks will relieve medical personnel from having to mentally correlate digital displays and paper records. In operating rooms, staff will no longer have to emulate the safety interlocks necessary for a patient?s survival. People once confined to expensive nursing homes, can potentially live longer, more productive and independent lives using these same medical device networks in their own home. To help realize this potential, we need to create the scientific foundation for the safe and easy composition of medical and health management devices. Much attention has been paid to the optimization of individual QoS requirements and their protocols. Yet, no system is truly functional without multiple protocols working together to achieve a balance of desirable qualities. Our research focus on the scientific foundation for the end-to-end composition of systems, backed by formally verifiable mathematical models, will push software architectures and systems to the next generation of safe and easily-composed medical device networks and other such Cyber-Physical Systems. QoS aware composition technologies are vital to the mass deployment of modern health care, assisted living, and other medical devices that will improve the quality of medical services, allowing people once confined to expensive nursing homes to live independent and productive lives in their own home. Although this technological foundation will be initially developed in the context of assisted living, we expect that it will be extended to help enable many more applications because QoS aware composition is a generic problem in many Cyber-Physical System application domains.