Mathematical programming formulations can yield faulty answers. Models can be unbounded, infeasible, or optimal with unrealistic answers. This article presents techniques for theory-based discovery of the cause of faulty models. The approaches are demonstrated in the context of linear...

This paper analyzes the optimal allocation problem of a small trading country facing an uncertain technology. It is involved in production of many commodities. Differentiability cannot be guaranteed, hence, the Ramsey-Euler condition of optimality needs to be modified. From the optimality...

This paper presents an asymptotic analysis of control models governed by stochastic ordinary differential equations. A sufficient condition of near-optimal controls is given based on Ekeland's principle. It is shown that, under some concavity assumptions, the e-maximum condition in terms of the...

This paper obtains decision and forecast horizons for undiscounted, continuous time one dimensional control systems. Some general conditions for the existence of horizons arising from the constraints imposed on the system are derived by using the optimality principle. These conditions are...

A simulation model based on a real wafer fabrication is used to investigate the robustness of the two boundary (TB) production control strategy to the existing uniform loading policy used in a semiconductor fab. Our findings confirm that the TB policy is the most robust of all when random...

This paper uses a complex network approach for the analysis of bilateral trade data between countries over the period 1970-2000. We compute the network community structure for every year between 1970 and 2000 and compare it to null community structures that emerge from various models based on...

We consider a semi-Markov modulated market consisting of a riskless asset or bond, B, and a risky asset or stock, S, whose dynamics depend on a semi-Markov process x. Using the martingale characterization of semi-Markov processes, we note the incompleteness of semi-Markov modulated markets and...

During this chaotic time before the full impact of the emerging flu is clear...glaring inadequacies of our flu preparedness program have come to the fore. Notably amongst these are the failures in school readiness. The lack of a systematized matrix or decision-making tree for local officials,...

This paper considers a dynamic lot sizing problem faced by a producer who supplies a single product to multiple customers. Characterized by their backorder costs as well as shipping costs, a customer with a high backorder cost has a greater need for the product than a customer with a low...