Optimal harvesting of a spatial renewable resource

In this paper we investigate the optimal harvesting of a renewable natural resource. While in most standard approaches the resource is located at a single point, we allow the resource to be distributed spatially. Consequently, an agent who exploits the resource has to travel from one location to another. For a fixed planning horizon, we investigate the speed and the path of harvesting chosen by the agent. We show that the agent adjusts this speed so as to visit each location only once, even in the absence of travelling cost. Since the agent does not return to any location for a second harvest, it is optimal to fully deplete the resource upon arrival. A similar type of bang–bang solution results when we drop the assumption of a constant harvesting rate: allowing for a variable harvesting rate, the agent chooses to fully exploit the resource either in the last or in the first travelling period. A society interested in conserving some of the resource thus has to take measures to limit the exploitative behaviour of the agent.     

Could the Faustmann model have an interior minimum solution?

The growth of an even-aged stand usually follows a S-shaped pattern, implying that the growth function is convex when stand age is low and concave when stand age is high. Given such a growth function, the Faustmann model could in theory have multiple optima and hence an interior local minimum solution. To ensure that the rotation age at which the first derivative of the land expectation value equals zero is a maximum, it is often assumed that the growth function is concave in stand age. Yet there is no convincing argument for excluding the possibility of conducting the final harvest before the growth function changes to concave. We argue that under normal circumstances the Faustmann model does not have any interior minimum. It is neither necessary nor proper to assume that the growth function is concave in the vicinity of the optimal rotation age. When the interest rate is high, the optimal rotation may lie in the interval on which the growth function is convex, i.e. before volume or value growth culminates.     

Positive and normative judgments implicit in U.S. tax policy,and the costs of unequal growth and recessions

Calculating the welfare implications of changes to economic policy or shocks requires economists to decide on a normative criterion. One approach is to elicit the relevant moral criteria from real-world policy choices, converting a normative decision into a positive inference, as in the recent surge of “inverse-optimum” research. We find that capitalizing on the potential of this approach is not as straightforward as we might hope. We perform the inverse-optimum inference on U.S. tax policy from 1979 through 2010 and argue that the results either undermine the normative relevance of the approach or challenge conventional assumptions upon which economists routinely rely when performing welfare evaluations.     

Positive welfare effects of trade barriers in a dynamic partial equilibrium model

We develop a simple two-region, cobweb-type dynamic partial equilibrium model to demonstrate the existence of optimal, possibly non-zero, trade barriers. A pure comparative statics analysis of our model suggests that a reduction of trade barriers, modeled as small but positive import tariffs, always enhances welfare. However, taking a dynamic perspective reveals that nonlinear trade interactions between two regions may generate endogenous price fluctuations which can hamper welfare. Finally, we allow special interest groups, such as consumers or producers from these two regions, to lobby for a particular level of trade barriers. Our model predicts that time-varying trade barriers may be another channel for market instability.     

Quantitative easing and the loan to collateral value ratio

We study optimal monetary policy in a New Keynesian model at the zero bound interest rate where households use cash alongside house equity borrowing to conduct transactions. The amount of borrowing is limited by a collateral constraint. When either the loan to value ratio declines or house prices fall, we observe a decrease in the money multiplier. We argue that the central bank should respond to the fall in the money multiplier and therefore to the reduction in house prices or the loan to collateral value ratio. We also find that optimal monetary policy generates a large and persistent fall in the money multiplier in response to the drop in the loan to collateral value ratio.     

Optimal dividend strategies with time-inconsistent preferences

This paper studies the optimal dividend strategies of an insurance company when the manager has time-inconsistent preferences. We consider the problem for a naive manager and a sophisticated manager, and analytically derive the optimal dividend strategies when claim sizes follow an exponential distribution. Our results show that the manager with time-inconsistent preferences tends to pay out dividends earlier than her time-consistent counterpart and that the sophisticated manager is more inclined to pay out dividends than the naive manager. Furthermore, we extend these results to the case with claim sizes following a mixed exponential distribution, and provide a numerical analysis to reveal the sensitivity of the optimal dividend strategies to changes in the premium, claims and surplus volatility.     

General existence of competitive equilibrium in the growth model with an endogenous labor–leisure choice

We prove the existence of competitive equilibrium in the canonical optimal growth model with elastic labor supply under general conditions. In this model, strong conditions to rule out corner solutions are often not well justified. We show using a separation argument that there exist Lagrange multipliers that can be viewed as a system of competitive prices. Neither Inada conditions, nor strict concavity, nor homogeneity, nor differentiability are required for existence of a competitive equilibrium. Thus, we cover important specifications used in the macroeconomics literature for which existence of a competitive equilibrium is not well understood. We give examples to illustrate the violation of the conditions used in earlier existence results but where a competitive equilibrium can be shown to exist following the approach in this paper.     

Government size,composition of public spending and economic growth in Brazil

The performance of the fiscal policy is largely affected by the relationship between government size, composition of public spending and economic growth. We use a theoretical framework to find optimal relations among these variables and confront them with a panel data for the Brazilian states. Private capital and government spending are substitute inputs in production as the Brazilian states require provision of public spending to fill gaps in the underdeveloped private sector. Public investment and current government expenditures are combined in fixed ratios in the overall government spending due to strong rigidity of the public budget. The optimal share of public investment is considerably lower than current expenditures, as occurs in developing countries characterized by low economic dynamism. Finally, the average tax burden from the data is below the estimated optimal level, meaning that there is space for increasing tax rate without harming economic growth for some Brazilian states.     

A two-generation new product model by considering forward-looking customers: Dynamic pricing and advertising optimization

Nowadays, one of the challenges of the firm managing multi-generation products is the forward-looking behavior of customers. Anticipating the introduction of a newer generation affects the demand and sales volume of the current generation and next generation. In this research, we investigated how to efficiently structure the pricing and advertising strategies of a firm that launches a two-generation new product to a market populated by forward-looking customers. Two thresholds were determined on the advertising expenditure of Generations 1 and 2. Our analysis proposed that the optimal pricing path of Generation 1 was monotonically decreasing or increasing and, then, decreasing. The optimal pricing of Generation 2 followed a concave curve. A heuristic solution method was proposed to solve the numerical examples. Findings revealed that, with increasing the customers' forward-looking behavior, the firm's profit would decrease. In the presence of forward-looking customers, it is beneficial for the firm to reduce the price of Generation 1 and allocate more budget to advertise Generation 2. Among other results, the advertising expenditure was shown to be positively affected by the number of potential customers and advertising effectiveness. Also, the length of the planning horizon had a negative effect on the advertising expenditure. A higher discount rate could lead to lower price, while higher advertising effectiveness and length of the planning horizon would result in higher price. Further, the results showed that, with increasing the word-of-mouth advertising effectiveness, the firm should increase the advertising expenditure and decrease the price firstly and, afterwards, decrease the advertising effort and increase the price.     

Optimal allocation of direct and embodied arable land associated to urban economy: Understanding the options deriving from economic globalization

Land resources do not flow directly but can be allocated as “embodied land” in goods and services during economic globalization. The term “embodied arable land” can help link local land allocation strategies to the global and national supply chains and trade activities, and suggest new lens in optimizing arable land allocation. China is facing a serious arable land shortage, especially in municipal administrative areas. Based on the nested input-output analysis (Nested IOA), this work takes Shanghai as an example, exploring the allocation of direct and embodied arable land of an urban economy within the process of economic globalization. The amount of embodied arable land associated with Shanghai economy is 6.09 Mha, broken down into local arable land use (0.20 Mha), domestic inflows (3.20 Mha) and foreign inflows (2.69 Mha). This area supports local final demand (4.32 Mha), domestic outflows (1.24 Mha) and foreign outflows (0.53 Mha). Land-related imbalances emerge in the study, namely the economy’s demand versus the city’s size, the arable land demand versus supply, and embodied arable land inflows versus outflows. Regarding the role of the urban economy in allocation of global arable land under economic globalization, on the one hand, Shanghai has intensively involved with a large amount of embodied foreign arable land resources, and has been heavy dependent on foreign embodied arable land; On the other hand, there is still large potential for Shanghai to take the opportunity of economic globalization for an optimal allocation of direct and embodied arable land. Policy suggestions on taking the opportunity of economic globalization for an optimal allocation of direct and embodied arable land are put forward.