Growth and liberalization of world trade have increased the risks of introduction of quarantine plant pests into importing countries. Import inspection of incoming commodities is a major tool for prevention of pest introductions related to world trade, but inspection capacities are limited. This article develops a theoretical and an empirical model for the optimal allocation of inspection effort for phytosanitary inspection of imported commodities when the inspecting agency has a limited capacity. It is shown that the optimal allocation of inspection effort equalizes marginal costs of pest introduction across risky commodity pathways. The numerical illustration finds the optimal allocation of inspection effort of chrysanthemum cuttings imported in the Netherlands. The numerical results suggest that ceteris paribus , greater inspection effort should be allocated to pathways whose inspection yields a greater reduction in the expected costs of pest introduction. The numerical results also suggest that import inspection has a high marginal benefit. In particular, we found that each additional euro of the inspection capacity decreases the expected costs of pest introduction from 18 to 49 euros, depending on the initial inspection capacity. 相似文献
A multi-echelon inventory system implies the existence of a hierarchy of stocking locations, and the dependence and interaction between them. We consider a multi-echelon, spare-part inventory management problem with outsourcing and backordering. The problem is characterized by deterministic repair time/cost, and supply and demand that lie within prescribed intervals and that vary over time. The objective is to minimize the total inventory and transportation costs. We develop a network model for problem analysis and present a network flow algorithm for solving the problem. We prove that the Wagner-Whitin property, known for the lot-sizing problem, can be extended to the spare-part inventory management problem under study. 相似文献
This study, based on panel data from 189 industrial enterprises in 1992‐96, shows that privatisation 'on average' produces little improvement in performance of Russian enterprises. However, disaggregating the process, we reveal that methods of privatisation do influence performance but the impact is not always positive. The state seems to be a passive shareholder. At the same time, our results suggest that majority state ownership is preferable to a state minority stockholding, possibly because the absence of a monitoring shareholder in the latter case does not permit managers to achieve their own objectives at the expense of other shareholders. 相似文献
This article develops a theory of multiunit auctions where shortsqueezes can occur in the secondary market. Both uniform anddiscriminatory auctions are studied and bidders can submit multiplebids. We show that bidders with short and long preauction positionshave different valuations in an otherwise common value setting.Discriminatory auctions lead to more short squeezing and higherrevenue than uniform auctions, ceteris paribus. Asymptotically,as the auction size approaches infinity, the two formats leadto equivalent outcomes. Shorts employ more aggressive equilibriumbidding strategies. Most longs strategically choose to be passive.Free riding on a squeeze by small, long players has no impacton these results, but affects revenue in discriminatory auctions. 相似文献
Finance and Stochastics - Sublinear functionals of random variables are known as sublinear expectations; they are convex homogeneous functionals on infinite-dimensional linear spaces. We extend... 相似文献
Finance and Stochastics - We present a detailed analysis of observable moment-based parameter estimators for the Heston SDEs jointly driving the rate of returns $(R_{t})$ and the squared... 相似文献
The classical discrete-time model of proportional transaction costs relies on the assumption that a feasible portfolio process has solvent increments at each step. We extend this setting in two directions, allowing convex transaction costs and assuming that increments of the portfolio process belong to the sum of a solvency set and a family of multivariate acceptable positions, e.g. with respect to a dynamic risk measure. We describe the sets of superhedging prices, formulate several no (risk) arbitrage conditions and explore connections between them. In the special case when multivariate positions are converted into a single fixed asset, our framework turns into the no-good-deals setting. However, in general, the possibilities of assessing the risk with respect to any asset or a basket of assets lead to a decrease of superhedging prices and the no-arbitrage conditions become stronger. The mathematical techniques rely on results for unbounded and possibly non-closed random sets in Euclidean space.