Target-based Optimization in Operations Management

Ph.DDOCTOR OF PHILOSOPH

Distributionally Robust Optimization: A Review

The concepts of risk-aversion, chance-constrained optimization, and robust optimization have developed significantly over the last decade. Statistical learning community has also witnessed a rapid theoretical and applied growth by relying on these concepts. A modeling framework, called distributionally robust optimization (DRO), has recently received significant attention in both the operations research and statistical learning communities. This paper surveys main concepts and contributions to DRO, and its relationships with robust optimization, risk-aversion, chance-constrained optimization, and function regularization

Demand for Reserves Under International Capital Mobility

In this research, I assess the determinants of foreign exchange reserves under endogenous capital flows. I consider a model where reserves represent collateral to international borrowing, which is endogenously determined by risk averse foreign investors. This is a departure from usual models of reserve accumulation, that focus solely on the portfolio decision of a central bank along the lines of optimal inventory control models or precautionary saving. In contrast to this view, I find that the expected effect on reserves of changes in the international interest rate or the volatility of the terms of trade is ambiguous if actions are simultaneous. However, if foreign investors and the central bank act sequentially, this ambiguity breaks down. Empirical evidence from OECD and non-OECD economies is suggestive: while LIBOR and terms of trade volatility positively affects the demand for reserves in OECD economies, the effects are reversed in non-OECD countries. This indicates that commitment issues are an important factor in the determination of reserves in non-OECD countries.

Macroeconomics and Finance: The Role of the Stock Market

The treatment of the stock market in finance and macroeconomics exemplifies many of the important differences in perspective between the two fields. In finance, the stock market is the single most important market with respect to corporate investment decisions. In contrast, macroeconomic modelling and policy discussion assign a relatively minor role to the stockmarket in investment decisions. This paper explores four possible explanations for this neglect and concludes that macro analysis should give more attention to the stock market. Despite the frequent jibe that "the stockmarket has forecast ten of the last six recessions," the stock market is in fact a good predictor of the business cycle and the components of GNP. We examine the relative importance of the required return on equity compared with the interest rate in the determination of the cost of capital, and hence,investment. In this connection, we review the empirical success of the Q theory of investment which relates investment to stock market evaluations of firms. One of the explanations for the neglect of the stock market in macroeconomics may be the view that because the stock market fluctuates excessively, rational managers will pay little attention to the market informulating investment plans. This view is shown to be unfounded by demonstrating that rational managers will react to stock price changes even if the stock market fluctuates excessively. Finally, we review the extremely important issue of whether the market does fluctuate excessively, and conclude that while not ruled out on a priori theoretical grounds, the empirical evidence for such excess fluctuations has not been decisive.

Using option pricing theory to estimate option value - a preliminary study

The purpose of this report is to compare and contrast two approaches to incorporating uncertainty when evaluating natural resource problems. The first approach incorporates option pricing theory which is derived from the financial economics literature. The second approach uses the concept of option value which has arisen in the literature of resource economics. The report introduces each approach separately and then compares and contrasts them. The report is in three parts - Part I deals with the option pricing theory approach to incorporating the value of uncertainty and irreversibility. Part II describes option value as commonly used in the resource economics literature. Part III describes the application of option pricing to a natural resource problem

The Fundamentals of Commodity Futures Returns

Commodity futures risk premiums vary across commodities and over time depending on the level of physical inventories, as predicted by the Theory of Storage. Using a comprehensive dataset on 31 commodity futures and physical inventories between 1969 and 2006, we show that the convenience yield is a decreasing, non-linear relationship of inventories. Price measures, such as the futures basis, prior futures returns, and spot returns reflect the state of inventories and are informative about commodity futures risk premiums. The excess returns to Spot and Futures Momentum and Backwardation strategies stem in part from the selection of commodities when inventories are low. Positions of futures markets participants are correlated with prices and inventory signals, but we reject the Keynesian "hedging pressure" hypothesis that these positions are an important determinant of risk premiums.

Ambiguity aversion in buyer-seller relationships: A contingent-claims and social network explanation

Negotiations between buyers and sellers (or suppliers) of goods and services have become increasingly important due to the growing trend towards international purchasing, outsourcing and global supply networks together with the high uncertainty associated with them. This paper examines the effect of ambiguity aversion on price negotiations using multiple-priors-based real options with non-extreme outcomes. We study price negotiation between a buyer and seller in a dual contingent-claims setting (call option holding buyer vs. put option holding seller) to derive optimal agreement conditions under ambiguity with and without social network effects. We find that while higher ambiguity aversion raises the threshold for commitment for the seller, it has equivocal effects on the buyer's negotiation prospects in the absence of network control. Conversely when network position and relative bargaining power are accounted for, we find the buyer's implicit price (or negotiation threshold) decreases (or increases) unequivocally with increasing aversion to ambiguity. Extending extant real options research on price negotiation to the case of ambiguity, this set of results provides new insights into the role of ambiguity aversion and network structures in buyer-seller relationships, including how they influence the range of negotiation agreement between buyers and sellers. The results also help assist managers in formulating robust buying/selling strategies for bargaining under uncertainty. By knowing their network positions and gathering background information or inferring the other party's ambiguity tolerance beforehand, buyers and sellers can anticipate where the negotiation is heading in terms of price negotiation range and mutual agreement possibilities