21,461 research outputs found

    Lecture Notes on The Optimal Growth Problem

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    These notes provide an introduction to the study of optimal growth in the one-sector neoclassical growth model in continuous time. The model is developed using the analogy of Robinson Crusoe living on a deserted island. Both the Hamiltonian method and the phase diagram are presented and explained on an intuitive level. Some familiarity with optimization theory and differential equations, as well as a thorough understanding of intermediatelevel microeconomics, is assumed.Optimal Growth

    An Economic Analysis of Highgrading in ITQ Fisheries Regulation Programs

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    ITQ management programs can provide incentives to discard low valued fish so that individual quota can he used for relatively more valuable fish. Such "highgrading" can also occur where there are other constraints on harvest, such as hold capacity. This paper compares and contrasts the exact conditions under which highgrading will occur with ITQ and other harvest constraints. Considering all costs, highgrading can be efficient with physical constraints hut it is an unfortunate artifact of lTQs. Whether or not highgrading will occur depends upon the price differential between high and low valued fish, the cost of sorting and discarding and the cost of re-harvest. Policies for correcting or reducing ITQ highgrading should it occur, are described.Fisheries Management, ITQs, highgrading, Environmental Economics and Policy, Resource /Energy Economics and Policy,

    Secure Layered Transmission in Multicast Systems with Wireless Information and Power Transfer

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    This paper considers downlink multicast transmit beamforming for secure layered transmission systems with wireless simultaneous information and power transfer. We study the power allocation algorithm design for minimizing the total transmit power in the presence of passive eavesdroppers and energy harvesting receivers. The algorithm design is formulated as a non-convex optimization problem. Our problem formulation promotes the dual use of energy signals in providing secure communication and facilitating efficient energy transfer. Besides, we take into account a minimum required power for energy harvesting at the idle receivers and heterogeneous quality of service (QoS) requirements for the multicast video receivers. In light of the intractability of the problem, we reformulate the considered problem by replacing a non-convex probabilistic constraint with a convex deterministic constraint. Then, a semidefinite programming relaxation (SDR) approach is adopted to obtain an upper solution for the reformulated problem. Subsequently, sufficient conditions for the global optimal solution of the reformulated problem are revealed. Furthermore, we propose two suboptimal power allocation schemes based on the upper bound solution. Simulation results demonstrate the excellent performance and significant transmit power savings achieved by the proposed schemes compared to isotropic energy signal generation.Comment: 7 pages, 3 figures, accepted for presentation at the IEEE International Conference on Communications (ICC), Sydney, Australia, 201

    Relative Efficiency of Charges and Quantity Controls in Fisheries with Continuous Stock Growth and Periodically Fixed Instrument Levels

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    This article presents a simple combination discrete-time/continuous-time model that incorporates continuous population dynamics and fishing activity together with periodic, rather than continuous, instrument adjustment into the decision process for choosing the optimal type and level of regulatory instrument. A per-unit tax and an allocated instantaneous harvest rate quota each drive the system along different time paths, and each results in a different present value of the stream of net benefits generated by harvesting the resource. The choice of instruments is fishery specific; it depends on the parameter values of the fishery in question.Environmental Economics and Policy, Resource /Energy Economics and Policy,

    Ex-vessel Pricing and IFQs: A Strategic Approach

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    In this paper, intraseasonal fishing is modeled as a differential game between fishermen in a total allowable catch–regulated fishery with and without individual fishing quotas (IFQs). Heterogeneous harvest values are included by incorporating time-specific harvest costs and a stock effect into fishermen’s profit functions. I also allow for strategic interaction among fishermen via ex-vessel price dynamics. The equilibrium harvest strategies of the differential games are solved numerically through the use of a genetic algorithm. I demonstrate how different harvesting sector environments lead to varying degrees of ex-vessel price increases when IFQs are implemented. The primary result shows that possible margins for competition among fishermen, beyond competition for a greater share of the total allowable catch, can still exist under IFQ management and may be substantial enough to be able to prevent sizeable rent transfers from the processing sector to the harvesting sector.individual fishing quotas, property rights, differential games, genetic algorithm

    Stackelberg Game for Distributed Time Scheduling in RF-Powered Backscatter Cognitive Radio Networks

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    In this paper, we study the transmission strategy adaptation problem in an RF-powered cognitive radio network, in which hybrid secondary users are able to switch between the harvest-then-transmit mode and the ambient backscatter mode for their communication with the secondary gateway. In the network, a monetary incentive is introduced for managing the interference caused by the secondary transmission with imperfect channel sensing. The sensing-pricing-transmitting process of the secondary gateway and the transmitters is modeled as a single-leader-multi-follower Stackelberg game. Furthermore, the follower sub-game among the secondary transmitters is modeled as a generalized Nash equilibrium problem with shared constraints. Based on our theoretical discoveries regarding the properties of equilibria in the follower sub-game and the Stackelberg game, we propose a distributed, iterative strategy searching scheme that guarantees the convergence to the Stackelberg equilibrium. The numerical simulations show that the proposed hybrid transmission scheme always outperforms the schemes with fixed transmission modes. Furthermore, the simulations reveal that the adopted hybrid scheme is able to achieve a higher throughput than the sum of the throughput obtained from the schemes with fixed transmission modes

    Wheat forecast economics effect study

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    A model to assess the value of improved information regarding the inventories, productions, exports, and imports of crop on a worldwide basis is discussed. A previously proposed model is interpreted in a stochastic control setting and the underlying assumptions of the model are revealed. In solving the stochastic optimization problem, the Markov programming approach is much more powerful and exact as compared to the dynamic programming-simulation approach of the original model. The convergence of a dual variable Markov programming algorithm is shown to be fast and efficient. A computer program for the general model of multicountry-multiperiod is developed. As an example, the case of one country-two periods is treated and the results are presented in detail. A comparison with the original model results reveals certain interesting aspects of the algorithms and the dependence of the value of information on the incremental cost function
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