The study of asset price characteristics of stochastic growth models such as the risk-free interest rate, equity premium, and the Sharpe-ratio has been limited by the lack of global and accurate methods to solve dynam...
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A decision theory framework can be a powerful technique to derive optimal management decisions for endangered species. We built a spatially realistic stochastic metapopulation model for the Mount Lofty Ranges Southern...
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A decision theory framework can be a powerful technique to derive optimal management decisions for endangered species. We built a spatially realistic stochastic metapopulation model for the Mount Lofty Ranges Southern Emu-wren (Stipiturus malachurus intermedius), a critically endangered Australian bird. Using diserete-time Markov,chains to describe the dynamics of a metapopulation and stochastic dynamic programming (SDP) to find optimal solutions, we evaluated the following different management decisions: enlarging existing patches, linking patches via corridors, and creating a new patch. This is the first application of SDP to optimal landscape reconstruction and one of the few times that landscape reconstruction dynamics have been integrated with population dynamics. SDP is a powerful tool that has advantages over standard Monte Carlo simulation methods because it can give the exact optimal strategy for every landscape configuration (combination of patch areas and presence of corridors) and pattern of metapopulation occupancy, as well as a trajectory of strategies. It is useful when a sequence of management actions can be performed over a given time horizon, as is the case for many endangered species recovery programs, where only fixed amounts of resources are available in each time step. However, it is generally limited by computational constraints to rather small networks of patches. The model shows that optimal metapopulation, management decisions depend greatly on the current state of the metapopulation,. and there is no strategy that is universally the best. The extinction probability over 30 yr for the optimal state-dependent management actions is 50-80% better than no management, whereas the best fixed state-independent sets of strategies are only 30% better than no management. This highlights the advantages of using a decision theory tool to investigate conservation strategies for metapopulations. It is clear from these results that the sequence of managem
A simplified inspection scenario is considered where a Micro Air Vehicle with limited endurance is tasked with search and classification in a multi-target environment and where false, that is, clutter, targets are pre...
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A simplified inspection scenario is considered where a Micro Air Vehicle with limited endurance is tasked with search and classification in a multi-target environment and where false, that is, clutter, targets are present. The sequential inspection operation, which includes a human operator for classification, is modelled, and a nonlinear discrete-time stochastic control problem is formulated. An analytic, closed-form, optimal control law is derived.
The optimal portfolio problem for a bank account, single risky stock and a rolling horizon bond is developed. The stochastic short-term interest rate with the Cox-Ingersoll-Ross (CIR) dynamics affects the prices of th...
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The optimal portfolio problem for a bank account, single risky stock and a rolling horizon bond is developed. The stochastic short-term interest rate with the Cox-Ingersoll-Ross (CIR) dynamics affects the prices of the stock and rolling horizon bond. The investment objective is maximizing expected CRRA utility of terminal wealth. The problem has been solved by the stochastic dynamic programming principle and the completion of squares technique. The closed-form optimal trading strategy is obtained. A numerical example illustrating the results is presented.
We consider a capacity planning optimization problem in a general theoretical framework that extends the classical Erlang loss modeland related stochastic loss networks to support time-varying workloads. The time hori...
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ISBN:
(纸本)9781595936394
We consider a capacity planning optimization problem in a general theoretical framework that extends the classical Erlang loss modeland related stochastic loss networks to support time-varying workloads. The time horizon consists of a sequence of coarse time intervals, each of which involves a stochastic loss network under a fixed multi-class workload that can change in a general manner from one interval to the next. The optimization problem consists of determining the capacities for each time interval that maximize a utility function over the entire time horizon, finite or infinite, where rewards gained from servicing customers are offset by penalties associated with deploying capacities in an interval and with changing capacities among intervals. We derive a state-dependent optimal policy within the context of a particular limiting regime of the optimization problem, and we prove this solution to be a symptotically optimal. Then, under fairly mild conditions, we prove that a similar structural property holds for the optimal solution of the original stochastic optimization problem, and we show how the optimal capacities comprising this solution can be efficiently computed.
We present a new approach to pricing American-style derivatives that is applicable to any Markovian setting (i.e., not limited to geometric Brownian motion) for which European call-option prices are readily available....
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We present a new approach to pricing American-style derivatives that is applicable to any Markovian setting (i.e., not limited to geometric Brownian motion) for which European call-option prices are readily available. By approximating the value function with an appropriately chosen interpolation function, the pricing of an American-style derivative with arbitrary payoff function is converted to the pricing of a portfolio of European call options, leading to analytical expressions for those cases where analytical European call prices are available (e.g., the Merton jump-diffusion process). Furthermore, in many settings, the approach yields upper and lower analytical bounds that provably converge to the true option price. We provide computational results to illustrate the convergence and accuracy of the resulting estimators.
This paper studies the problem of the existence of stationary optimal policies for finite state controlled Markov chains, with compact action space and imperfect observations, under the long-run average cost criterion...
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This paper studies the problem of the existence of stationary optimal policies for finite state controlled Markov chains, with compact action space and imperfect observations, under the long-run average cost criterion. It presents sufficient conditions for existence of solutions to the associated dynamicprogramming equation, that strengthen past results. There is a detailed discussion comparing the different assumptions commonly found in the literature. (c) 2005 Elsevier B.V. All rights reserved.
This paper develops a discretized version of a stochastic model of the economic growth and studies its convergence and stability properties. A nonlinear model of the economic growth, which involves the production, tec...
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This paper develops a discretized version of a stochastic model of the economic growth and studies its convergence and stability properties. A nonlinear model of the economic growth, which involves the production, technology stock, and their rates as the main variables, is considered. We analyze the case where the production function does not satisfy the Inada conditions and we show that, in this case, a sufficient condition for the existence of a unique steady state is that the marginal utility function should possess a horizontal and vertical asymptotic elasticity.
This paper considers a class of multi-period flexible supply policies with options and capacity constraints. The main results are to characterize the optimal ordering and purchasing options policy and the minimum expe...
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This paper considers a class of multi-period flexible supply policies with options and capacity constraints. The main results are to characterize the optimal ordering and purchasing options policy and the minimum expected cost in a period and thereafter under the assumptions about the options and ordering quantities. (c) 2005 Elsevier B.V. All rights reserved.
This paper concerns two families of Markov decision problem that fall within the family of (bi-directional) restless bandits, an intractable class of decision processes introduced by Whittle. The spinning plates probl...
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This paper concerns two families of Markov decision problem that fall within the family of (bi-directional) restless bandits, an intractable class of decision processes introduced by Whittle. The spinning plates problem concerns the optimal management of a portfolio of reward-generating assets whose yields grow with investment but otherwise tend to decline. In the model of asset exploitation called the squad system, the yield from an asset tends to decline when it is used but will recover when the asset is at rest. In all cases, simply stated conditions are given that guarantee indexability of the problem, together with conditions necessary and sufficient for its strict indexability. The index heuristics for asset activation that emerge from the analysis are assessed numerically and found to perform very strongly.
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