A Hospital Information Systems (HIS) have turned a hospital into a gigantic computer with huge computational power, huge storage and wired/wireless local area network. On the other hand, a modern medical device, such as echograph, is a computer system with several functional units connected by an internal network named a bus. Therefore, we can embed such a medical device into the HIS by simply replacing the bus with the local area network. This paper designed and developed two embedded systems, a ubiquitous echograph system and a networked digital camera. Evaluations of the developed systems clearly show that the proposed approach, embedding existing clinical systems into HIS, drastically changes productivity in the clinical field. Once a clinical system becomes a pluggable unit for a gigantic computer system, HIS, the combination of multiple embedded systems with application software designed under deep consideration about clinical processes may lead to the emergence of disruptive innovation in the clinical field.

A new hardware-software reliability model is developed where lifetimes and repair times of the software subsystem have general system state-dependent distributions. The hardware subsystem constitutes an independent alternating renewal process having exponential up-times and general down-times. Multiple errors may be introduced or removed through repairs. The model is formulated as a multivariate stochastic process. To study the performance of the software subsystem under the influence of hardware failures, expressions of various time dependent performance measures are derived. Using the matrix Laguerre transform of U. Sumita (1984), corresponding computational procedures are also developed. A numerical example is given demonstrating the speed, accuracy, and stability of these procedures.