Two 1-Server n-Unit Systems with Preventive Maintenance and Repair

This paper deals with the availability and reliability analysis of two different 1-server n-unit systems with preventive maintenance and repair. Initially, one unit operates and the remaining n - 1 units are kept as cold standbys. In the first system the time to failure and the time to preventive maintenance of a unit are arbitrarily distributed. In the second system, each unit consists of 2 components connected in series. When a unit fails, the failed component is taken up for repair while the other waits for preventive maintenance. Explicit expressions for the Laplace transform of the mean down-time of the system in [0, t] and for the mean time to system failure are obtained. Steady-state availability of the system is also discussed. A few special cases have been studied.     

Geographic Information System for Coordination of Fast-Track Projects

To meet the increasing demands to deliver projects within a short period of time, many projects are being executed on a fast-track basis. On fast-track projects, the construction begins when the design is between 35% and 65% complete. This poses numerous challenges. One of the key challenges is to ensure that the flow of information and deliverables between the engineering, procurement, and construction is synchronized. This work initially studied the information flow on process plant projects, the disruptions to information flow, and the problems faced due to the disruptions. It was identified that an information system that has the capability to (1) capture the relationships between different deliverables, (2) record the status of deliverables, and (3) process queries from any of the teams regarding status and impact of disruptions will support the decision-making required for rapid development of pragmatic plans. Further, as the information requirements require the representation and querying of both spatial and nonspatial data, the design and implementation of the system using the concepts and features of a geographic information system was explored. The paper discusses the design of the geographic information system and its implementation within the AutoCAD Map environment. The use of the system to retrieve information required for project coordination is illustrated through sample queries.