Semi‐Parametric Models for the Multivariate Tail Dependence Function – the Asymptotically Dependent Case

Abstract. In general, the risk of joint extreme outcomes in financial markets can be expressed as a function of the tail dependence function of a high‐dimensional vector after standardizing marginals. Hence, it is of importance to model and estimate tail dependence functions. Even for moderate dimension, non‐parametrically estimating a tail dependence function is very inefficient and fitting a parametric model to tail dependence functions is not robust. In this paper, we propose a semi‐parametric model for (asymptotically dependent) tail dependence functions via an elliptical copula. Under this model assumption, we propose a novel estimator for the tail dependence function, which proves favourable compared to the empirical tail dependence function estimator, both theoretically and empirically.     

Scheduling professionals in the retail pharmacy chain

To control operating costs, a zero-one integer programming model is developed to assist pharmacy staff scheduling decisions. Variable scheduling needs are met by the assignment of relief (mobile) pharmacists to help or temporarily replace full-time pharmacists. Assignments of relief pharmacists over a two-week planning horizon are determined with consideration given to variations in wage rates and travel costs together with the underlying corporate, contractual and operating constraints. The developed model has been applied with considerable success using data collected from a business district in the US located in northern Louisiana related to a national retail chain pharmacy. Forecasting the number of chain retail outlets in the near future has been also performed and the results obtained argue in favor of adopting the model by the entire chain.     

"I'm still swimming"

Treatment of bipolar affective disorder is often difficult and lengthy. Enabling participation in a return to work process is equally daunting, primarily due to the dramatic and oftentimes sudden shifts in mood and thought. The following case study attempts to illustrate the complicated process of return to [and stay at] work for an individual who has mixed bipolar affective disorder. Work has always played a significant role in Ray's life and remains a valued goal and accomplishment for Ray. Work has been a means to structure and routine, and it has been from this routine that wellness has become possible for Ray. The metaphor, "I'm still swimming" helps to illustrate the continual treading of water, which both Ray and his occupational therapist [first author] have experienced over the past 6 years. This case study illustrates the strategies employed in maximizing the person-environment-occupation fit for Ray, as well as the importance of collaboration and partnership in the return-to-work process. It is also meant to stimulate thought and discussion about what is important for occupational therapists, and other health professionals to consider, when attempting the task of return-to-work for an individual with mixed bipolar affective disorder.