A model of incentive contracts for just-in-time delivery

A mathematical model is used to analyze how to structure on-time delivery incentives in a contract between a buyer and a single supplier of raw materials when early shipments are forbidden. The buyer's choice of incentives takes the supplier's cost-minimizing response to incentives into account. The least cost incentive a buyer can select is specified by a probability of on-time delivery and an incentive scheme to achieve that probability. These optimal solutions are characterized without specifying the flow time distribution. A Method of selecting incentives that can help buyers improve on-time delivery performance is provided; however, the limitations of incentives are also considered. Achieving exactly 100% on-time delivery is shown to be non-optimal and only feasible under specific conditions. When management can not specify the shortage cost, their selection of a desired probability of on-time delivery allows for the determination of an imputed shortage cost.     

The blocking lemma and group incentive compatibility for matching with contracts

This paper considers a general class of two-sided many-to-one matching markets, so-called matching markets with contracts. We study the blocking lemma and group incentive compatibility for this class of matching markets. We first show that the blocking lemma for matching with contracts holds if hospitals’ choice functions satisfy substitutes and the law of aggregate demand. The blocking lemma for one-to-one matching (Gale and Sotomayor, 1985) and that for many-to-one matching (Martínez et al., 2010) are special cases of this result. Then, as an immediate consequence of the blocking lemma, we show that the doctor-optimal stable mechanism is group strategy-proof for doctors if hospitals’ choice functions satisfy substitutes and the law of aggregate demand. Hatfield and Kojima (2009) originally obtain this result by skillfully using the strategy-proofness of the doctor-optimal stable mechanism. In this paper we provide a different proof for the group incentive compatibility by applying the blocking lemma.     

Effects of constrained supply and price contracts on agricultural cooperatives

Planning strategies depend in part on the supply flow structure of a supply chain. In food supply chains, many firms are constrained by raw material supply (e.g. vegetables and milk). This paper first examines the economic consequences of constrained supply in agricultural cooperatives. Secondly, it deals with the effects of adding price contracts to the current cooperative contract. This model combines an inventory policy approach and a Monte-Carlo simulation, to take into account price uncertainty. We illustrate our results using the case of a dairy cooperative.     

The coordinating contracts for a fuzzy supply chain with effort and price dependent demand

This paper investigates the coordination of a two-echelon supply chain with fuzzy demand that is dependent on both retail price and sales effort. In contrast with the centralized and decentralized decision models, two coordinating models based on symmetric information and asymmetric information about retailer’s scale parameter are developed by game theory, and the corresponding analytical solutions are obtained. Theoretical analysis and numerical examples yield the maximal supply chain profits in two coordination situations are equal to that in the centralized situation and greater than that in the decentralized situation. Furthermore, under asymmetric information contract, the maximal expected profit obtained by the low-scale-level retailer is higher than that under symmetric information contract.     

Managing risks in information systems outsourcing: An approach to analyzing outsourcing risks and structuring incentive contracts

Information systems outsourcing is now almost standard practice for many companies. Outsourcing the information processing activities is a complex issue that entails considerable implications for the strategy of the firm. An important mechanism for managing the performance of outsourcing vendors is incentive contracts. But to develop an outsourcing contract the IS manager must quantify risks and benefits. However methods and tools for analyzing and quantifying outsourcing risks that IS managers have at their disposal are rudimentary. In this paper we offer a method and some mathematical models for analyzing risks and constructing incentive contracts for IS outsourcing. We are aware that most managers do not like to use mathematical models, consequently we have minimized the technical discussion and have illustrated how this model could be implemented using spreadsheet software for ease of use.     

Oligopoly models for market price of electricity under demand uncertainty and unit reliability

Several oligopoly models have been proposed for representing strategic behavior in electricity markets, which include Bertrand, Cournot, and Supply Function Equilibrium (SFE). For the most part, these models are deterministic, with the exception of the SFE originally developed by Klemperer and Meyer. However, their model does not include supply side uncertainties. In this paper, we consider both load and supply side uncertainties (resulting from generator availabilities). We obtain Nash equilibrium solutions for Cournot and SFE models, in which asymmetric firms (whose generating units have different costs and capacities) submit their bids so that each firm’s expected profit is maximized.     

The average shadow price for MILPs with integral resource availability and its relationship to the marginal unit shadow price

The economic significance of the average shadow price for integer and mixed integer linear programming (MILP) problems has been established by researchers [Kim and Cho, Eur. J. Operat. Res. 37 (1988) 328; Crema Eur. J. Operat. Res. 85 (1995) 625]. In this paper we introduce a valid shadow price (ASPIRA) for integer programs where the right-hand side resource availability can only be varied in discrete steps. We also introduce the concept of marginal unit shadow price (MUSP). We show that for integer programs, a sufficient condition for the marginal unit shadow price to equal the average shadow price is that the Law of Diminishing Returns should hold. The polyhedral structures that will guarantee this equivalence have been explored. Identification of the problem classes for which the equivalence holds complements the existing procedure for determining shadow price for such integer programs. The concepts of ASPIRA and MUSP introduced in this paper can play a vital role in resource acquisition plans and in defining efficient market clearing prices in the presence of indivisibilities.     

On the construction of hourly price forward curves for electricity prices

Computational Management Science - There are several approaches in the literature for the derivation of price forward curves (PFCs) which distinguish among each other by the procedure employed for...     

Integrating inventory control and a price change in the presence of reference price effects: a two-period model

Demand and procurement planning for consumer electronics products must cope with short life cycles, limited replenishment opportunities and a willingness to pay that is influenced by past prices and decreases over time. We therefore propose the use of an integrated pricing and inventory control model with a two-period linear demand model, in which demand also depends on the difference between a price-history-based reference price and the current price. For this model we prove that the optimal joint pricing/inventory policy for the replenishment opportunity after the first period is a base-stock list-price policy. That is, stock is either replenished up to a base-stock level and a list-price is charged, or it is not replenished and a discount is given that increases with the stock-level. Furthermore, we use real-world cell phone data to study the differences between an integrated policy and traditional sequential optimization, where prices are initially optimized based on the expected demand and ordering cost, and the resulting demand distribution is used to determine an optimal inventory policy. Finally, we discuss possible extensions of the model.     

Welfare and research and development incentive effects of uniform and differential pricing schemes

Computational Management Science - This paper is about the application of optimization methods to the analysis of three pricing schemes adopted by one manufacturer in a two-country model of...     

Forming an approximating construction for calculation and implementation of optimal control in real time

A new approach to realization of the time-optimal control in real time for linear systems under control with a constraint is proposed. It is based on dividing the computer costs into those made in advance of the control process and those carried out as it proceeds. The preliminary computations do not depend on a particular initial condition and rely on approximation of attainability sets in different periods of time by a union of hyperplanes. Methods of their construction and identification of the support hyperplane are given. Methods of approximate finding and subsequent refining of the normalized vector of the initial conditions of the adjoint system as well as switching times and instants of switching of time-optimal control are proposed. Results of modeling and numerical calculations are presented.     

On the construction and calculation of optimal nonlifting critical airfoils

Numerical calculations are carried out in the hodograph plane to construct optimal critical airfoil shapes and the flow about them. These optimal airfoil shapes give the highest free-stream Mach numberM for a given thickness ratio and tail angle _t (nonlifting) for which the flow is nowhere supersonic. A relationship betweenM and for various _t is given. Analytical and numerical solutions to the same problem are found on the basis of transonic small-disturbance theory. These results provide a limiting case asM 1, 0 and agree well with the calculations of the full problem. Using a numerical method to calculate the flow about general (subsonic) airfoils, a comparison is made between the critical free-stream Mach numbers for some standard airfoil shapes and the optimal free stream Mach number of the corresponding and _t . A significant increase in the critical free-stream Mach number is found for the optimal airfoils.     

On the construction of samples for testing approximate optimization methods for estimate calculation algorithms

To validate approximate optimization schemes for estimate calculation algorithms (ECAs), it is necessary to compute the optimal height, which cannot be done in a reasonable amount of time. A variety of samples are built for which the optimal height of the ECAs is known by construction.     

Penalties,rewards, and inspection: provisions for quality in supply chain contracts

Rewards for better quality, penalties for poorer quality, and the type of inspection policy are among the most common quality-related provisions of supply chain contracts. In this paper, we examine the effect of rewards, penalities, and inspection policies on the behaviour of an expected cost minimizing supplier. We assume that the supplier selects a batch size and target quality level in order to meet a buyer's deterministic demand. We show that the reward and/or penalty that motivates a supplier to deliver the buyer's target quality depends upon the inspection policy. We also show that, when sampling inspection is used, penalties and rewards are substitutes for one another in motivating the supplier and that there exists a unique reward/penalty combination at which the buyer's expected cost of quality is zero.     

Efficient construction of a smooth nonparametric family of empirical distributions and calculation of bootstrap likelihood

This paper considers the efficient construction of a nonparametric family of distributions indexed by a specified parameter of interest and its application to calculating a bootstrap likelihood for the parameter. An approximate expression is obtained for the variance of log bootstrap likelihood for statistics which are defined by an estimating equation resulting from the method of selecting the first-level bootstrap populations and parameters. The expression is shown to agree well with simulations for artificial data sets based on quantiles of the standard normal distribution, and these results give guidelines for the amount of aggregation of bootstrap samples with similar parameter values required to achieve a given reduction in variance. An application to earthquake data illustrates how the variance expression can be used to construct an efficient Monte Carlo algorithm for defining a smooth nonparametric family of empirical distributions to calculate a bootstrap likelihood by greatly reducing the inherent variability due to first-level resampling.     

Binary operations and lattice structure for a model of matching with contracts

We consider a restricted model of many-to-one matching with contracts and we order the set of stable allocations according both to the unanimous-for-doctors partial ordering and Blair’s partial ordering for hospitals. We define two binary operations to calculate the least upper bound and greatest lower bound for each pair of elements of this set in a simple way. By using these operations, we show that the set of stable allocations has dual lattice structures, thus reflecting an expected counterposition of interests between both sides of the market.     

Project-driven supply chains: integrating safety-stock and crashing decisions for recurrent projects

We study a new class of problems—recurrent projects with random material delays, at the interface between project and supply chain management. Recurrent projects are those similar in schedule and material requirements. We present the model of project-driven supply chain (PDSC) to jointly optimize the safety-stock decisions in material supply chains and the crashing decisions in projects. We prove certain convexity properties which allow us to characterize the optimal crashing policy. We study the interaction between supply chain inventory decisions and project crashing decisions, and demonstrate the impact of the PDSC model using examples based on real-world practice.     

Average shadow price and equilibrium price: A case study of tradable pollution permit markets

Shadow prices indicate implicit values of limited resources at the margin and provide important information in decision making for resource management. In continuous economic models, shadow prices associated with demand-supply balance constraints represent consumers’ willingness to pay and producers’ marginal cost, hence they correspond to market equilibrium prices. As well known, however, marginal analysis fails in the case of discrete optimization, such as mixed integer programming. An alternative concept has been introduced in the literature to measure the value of an extra unit of a limited resource in such cases. This concept is based on average rather than marginal values, thus called the average shadow price, and interpreted in the same way as conventional shadow prices. Whether average shadow prices in a discrete economic model can serve as market equilibrium prices has not been addressed in the related literature. The present paper addresses this issue in an empirical setting. Using a tradable pollution permit market as an example, where firms’ YES/NO type technology adoption decisions are represented by binary variables, we show that the average shadow price of tradable permits can be interpreted as the equilibrium price only when certain conditions related to the cost structure and emission levels hold. On the other hand, we show that an iterative procedure based on individual firms’ cost minimizing behavior presents a better approach for finding a price that can eliminate or reduce the gap between demand and supply of permits in the market.     

The construction of meanings for geometric construction: Two contrasting cases

Dynamic geometry software seems to offer new approaches to the teaching and learning of geometry. Interest has been particularly intense in Britain where geometry has almost disappeared from the curriculum. In this paper we draw on our experiences of using Logo with children and adult students as a way of thinking about the design of geometrical activities for young children who lack cultural support in this domain and who are at early stages of conceptual development. We explore how the nature of Cabri Geometry activities, in conjunction with previous connected experiences, may influence the construction of meaning for geometric construction.     

The IASB Insurance Project for life insurance contracts: Impact on reserving methods and solvency requirements

In this communication, we review the fair value-based accounting framework promoted by the IASB Insurance Project for the case of a life insurance company. In particular, for the case of a simple participating contract with minimum guarantee, we show that the fair valuation process allows for the identification of a suitable safety loading to hedge against default risk; furthermore, we show that, when compared with the “traditional” accounting system based on the construction of mathematical reserves, the fair value approach offers a sounder reporting framework in terms of covering of the liability, implementation costs, volatility of assets and liabilities and solvency capital requirements.