Managing uncertainty in on-demand air travel

Fractional management companies (FMCs) that provide on-demand air travel services experience frequent changes in aircraft availability and flight requests. We propose scheduling heuristics which are both cost-effective and persistent (i.e., close to the original schedule) to address the uncertainty. The heuristics include pro-actively enforcing idleness of aircraft in creating the original schedule, strategically repositioning aircraft to serve yet-unknown demand and dense scheduling. Computational experiments are conducted in a simulator that mimics FMCs’ daily operations. Simulation results quantify the value of each heuristic, which can be easily incorporated into existing computational methods used in FMCs for static scheduling problems.     

The legal framework and initiatives for promoting safety in the United Arab Emirates

Injury is a leading cause of morbidity and mortality in the United Arab Emirates (UAE). The UAE is a rapidly developing country with fast economic growth, demographical and environmental changes that are associated with new hazards emerging at a similar pace. The UAE as a federal entity has federal and local systems responsible for safety policy, regulations and enforcement. To set priorities for safety promotion and injury prevention, it is necessary to have data on the most frequent external causes of injury and the main individual, equipment and environmental risk factors that contribute to injury. However good quality data for injury prevention are scarce. The aim of this paper is to describe the scale of injury as a public health problem in the UAE, and the development of safety policies, regulations and promotion efforts with special emphasis on traffic, occupational and child safety.     

Decision making in the beer game and supply chain performance

The beer game has been used to emphasize, investigate, and analyze supply chain inefficiencies as well as the effect of decision makers’ biases. This paper investigates the short- and long-run performance in the beer distribution game by analyzing Sterman’s (Manag Sci 35(3): 321–339, 1989) model that simulates decision-making. In this model, the system may have chaotic behavior depending on the heuristics used by decision makers. We investigate how quickly the system reaches a steady state (if at all). It is known that ignoring supply line (outstanding orders) leads to the bullwhip effect in experimental research. Among other results, we show that the short-term performance of a supply chain is not a predictor of the long-term performance even when decision makers fully recognize outstanding orders. Results of the simulation and practical implications are discussed.     

Expansion planning for transmission network under demand uncertainty: A real options framework

In recent years, there has been much expectation that transmission expansion planning should address ever increasing demands for transmission services under significant and complex economic and regulatory uncertainties. In this article, toward meeting the aforementioned expectation, we develop and analyze a real options framework that provides the valuation of a transmission owner's option to expand in his or her network. What distinguishes our framework from the extant literature is that the evolution of the demand follows a geometric Brownian motion process, it explicitly accounts for the physical flow of the electric power economically manifested as the locational marginal prices, and it shows how the values of the expansion options can be determined in the transmission network. Furthermore, our framework shows how to value an option to expedite or delay can be determined given that a specific expansion is planned. An extensive numerical example is presented to illustrate the key features of our framework.     

Multi-product newsvendor problem with value-at-risk considerations

We consider the single period stochastic inventory (newsvendor) problem with downside risk constraints. The aim in the classical newsvendor problem is maximizing the expected profit. This formulation does not take into account the risk of earning less than a desired target profit or losing more than an acceptable level due to the randomness of demand. We utilize Value at Risk (VaR) as the risk measure in a newsvendor framework and investigate the multi-product newsvendor problem under a VaR constraint. To this end, we first derive the exact distribution function for the two-product newsvendor problem and develop an approximation method for the profit distribution of the N-product case (N>2). A mathematical programming approach is used to determine the solution of the newsvendor problem with a VaR constraint. This approach allows us to handle a wide range of cases including the correlated demand case that yields new results and insights. The accuracy of the approximation method and the effects of the system parameters on the solution are investigated numerically.     

Institutional quality,economic freedom and stock market volatility in the MENA region

How can a government help secure low-cost equity financing? This study offers an answer that a government can secure sustainable economic progress when policies of economic freedom are well institutionalized in a way that results in low equity volatility, thus low-cost equity financing. This study examines the quantitative and empirical associations between elements of Economic Freedom Index (being treated in this study as a proxy for institutional quality) and stock market volatility. The authors classify the institutional quality into three levels: high, medium and low. The data cover the years 1996–2014 for the MENA countries. The statistical tests include fixed and random effects, linearity versus non-linearity. The results show that stock market volatility can be mitigated and reduced when economic freedom is associated with an effective enforcement of law and efficient regulations. Nevertheless, the high freedom from corruption results in active equity trading which is associated with high volatility that leads in turn to high cost of equity financing. The study contributes to the literature in terms of offering practical insights on the pillars of economic freedom that policymakers must improve in order to mitigate or reduce equity volatility, therefore cost of equity financing.