Maintenance can be the factor of either increasing or decreasing system's availability, so it is valuable work to evaluate a maintenance policy from cost and availability point of view, simultaneously and according to decision maker's priorities. This study proposes a Partially Observable Markov Decision Process (POMDP) framework for a partially observable and stochastically deteriorating syste...

the determination of the ultimate pit limit (upl) is the first step in the open pit mine planning process. in this stage that parts of the mineral deposit that are economic to mine are determined. there are several mathematical, heuristic and meta-heuristic algorithms to determine upl. the optimization criterion in these algorithms is maximization of the total profit whilst satisfying the...

as one of the most important products of iran, pistachio has a significant share in non-oil revenues. its annual foreign exchange earnings are over 800 million dollars. however, production of this nut in the country’s major production centers is faced with many problems regarding the efficiency and productivity of the inputs. this study was performed by using two-stage cluster sampling method. ...

Profit maximization (PM) is to select a subset of users as seeds for viral marketing in online social networks, which balances between the cost and profit from influence spread. We extend PM that under general strategy, form continuous (CPM-MS) problem, whose domain on integer lattices. The objective function our CPM-MS dr-submodular, but non-monotone. It typical case unconstrained dr-submodula...