Modern research emphasizes Pervasive Computing change faces, learning cultures, structures, communications, intellectual properties, information securities, data presentations and web displays to make attraction for human interaction. Pervasive systems have a broad range of applications but it is relatively challenging for pervasive applications to meet emergence into existing physical environment and newly built structure requirements. Due to their interaction to gather information and change the environment via activating devices independently is highlighted. Security of the pervasive devices and applications which control our activities has primary importance and will be destroyed, if the pervasive system operations are not secure. There is a need to improve the security measures for data to travel rapidly, unbroken, unchanged and invisible by deceptive recipients. Pervasive Computing allows users to get information and services access anytime and anywhere but need to discuss issues and solutions to deliver secure information with privacy and trust. Possible solutions for these challenges of Pervasive Computing interaction between human are emphasized. A collection of papers and articles have been collected in order to investigate the previous study of Pervasive Computing interaction and its challenges. Is it possible for us to understand what the scientific world will be close to generate new avenues? Expectations of future bring new openings for user interaction with systems, data, information and the environments in which they live, work and play.

This paper considers a preventive maintenance model for an operating system that works for jobs at random times and is imperfectly maintained upon failure. As a failure occurs, the system suffers one of two types minimal repair and type II (non-repairable) failure is removed by a corrective replacement. A modified random and age replacement model is considered in which the system is replaced at a planned time T or at a random working time the total expected cost and optimal schedule of preventive replacement time which minimizes it are presented analytically and discussed numerically. It random working time is small enough, the system can be operating for a longer time and avoid unnecessary replacements when replacement last is done. Finally, the proposed model extends some existing results.