This paper investigates a novel two-phase preventive maintenance policy for a single-component system with an objective of maximizing the revenue generated by the performance-based contracting (PBC). The system undergoes a defective state before failure, and produces signal hinting the condition. The maintenance policy consists of two phases: imperfect maintenance phase followed by postponed replacement phase. In the imperfect maintenance phase, inspection is performed to reveal the defective state, leading to a possible repair. Both the inspection and the repair are imperfect. In the postponed replacement phase, preventive replacement is performed during the upcoming scheduled maintenance window, before which no inspection or repair is executed. The expected net revenue under PBC is maximized via the joint optimization of the inspection interval, number of inspection and preventive replacement interval. We apply the model to a case from a steel converter plant, and the results show that our proposed maintenance policy outperforms some existing maintenance policies in terms of the net revenue.

The reliability of network systems of various structures has been studied by many researchers. However, most of the works just consider the reliability of a single network system. In practice, different networks may be interdependent such that the failure in one network may result in the failure in another network. The cascading failures have been shown to be catastrophic by some researchers. However, the quantitative evaluation for the reliability of interdependent networks has not been proposed. In this paper, a multi-valued decision diagram based approach is presented to evaluate the reliability of interdependent networks. Illustrative examples are proposed to demonstrate the application of the framework.

Block withholding attack is an action where a miner who has found a legal block chooses not to submit it but rather directly abandons it. This attack makes the mining pool lose all bitcoin rewards contained within the block. In this paper, we construct a generalized model where two participants can choose to either cooperate with each other or employ a block withholding attack in the mining pool. To make the model more realistic, we consider both the cost of partial proof of work and the cost of cooperation. We also calculate the reward-per-time instead of profit-per-time to better measure the payoffs of each party. Further, we discuss the case where the payoff function and cost function are directly related to the computational power. The pure strategy and mixed strategy are analyzed respectively and the segmentations of the equilibrium are shown. We demonstrate that increasing the information asymmetry by utilizing information conceal mechanisms could lower the occurrence of the BWH attack. 1. Introduction The concept of Bitcoin was originally proposed by Nakamoto [1], and it is basically known as an open source software and a P2P network constructed on the software. Unlike most existing currencies, Bitcoin does not rely on a specific currency institution for its creation and distribution. Instead, it is generated by a large number of calculations based on a specific algorithm. The Bitcoin economy uses a distributed database of nodes in the entire P2P network to confirm and record all transaction behaviors, and it employs cryptographic design to ensure the security of all aspects of currency circulation. The advantages of this new economy include decentralization, worldwide circulation, exclusive ownership, lower transaction costs, no hidden costs and crossplatform mining. Swan [2] performed a detailed introduction to blockchain, which includes the concepts, features and functionality of Bitcoin and how one can use the blockchain for automated tracking of all digi