A fractionated spacecraft is an innovative application of a distributive space system. To fully understand the impact of various uncertainties on its development, launch and in-orbit operation, we use the stochastic missioncycle cost to comprehensively evaluate the survivability, flexibility, reliability and economy of the ways of dividing the various modules of the different configurations of ...

This paper presents the effects of salvage value on the optimal age-replacement policy for non-repairable products sold with a renewing free-replacement warranty (RFRW). Cost models from the customer’s perspective are developed for both warranted, and non-warranted products. The corresponding optimal replacement ages are derived such that the long-run expected cost rate is minimized. Under the ...

BACKGROUND The costs and benefits of controlling nosocomial spread of antibiotic-resistant bacteria are unknown. METHODS We developed a mathematical algorithm to determine cost-effectiveness of infection control programs and explored the dynamical interactions between different epidemiological variables and cost-effectiveness. The algorithm includes occurrence of nosocomial infections, attrib...

‎artificial neural networks have the advantages such as learning, ‎adaptation‎, ‎fault-tolerance‎, ‎parallelism and generalization‎. ‎this ‎paper is a scrutiny on the application of diverse learning methods‎ ‎in speed of convergence in neural networks‎. ‎for this aim‎, ‎first we ‎introduce a perceptron method based on artificial neural networks‎ ‎which has been applied for solving a non-singula...

This paper provides a replacement policy for warranty products with different failure rate from the consumer’s viewpoint. Assume that the product is replaced once within a finite planning horizon, and the failure rate of the second product is lower than the failure rate of the first product. Within warranty period (WP), the failed product is corrected by minimal repair without any cost to the c...

Data Grid is a new kind of data management infrastructure. To improve access efficiency, large amounts of data on Data Grids need to be replicated in the form of replicas at distributed sites. Due to the limited storage capacity, a good replica replacement algorithm is needed. This paper proposes a replica replacement algorithm based on value-cost prediction, which achieves a good balance betwe...