Network coding, first studied by Yeung and Zhang and Ahlswede et al., reveals that if coding is applied at the nodes in a network, rather than routing alone, the network capacity can be increased. Li et al. and subsequently Koetter and Medard proved that linear network coding is sufficient to achieve the maximum capacity in a single-source finite acyclic network.
Consequently, linear network coding for single-source finite acyclic networks has been a subject of much research interest. We refer the reader to (see also) for a tutorial on the subject. In this work, they classify linear network codes for single-source finite acyclic networks into four classes: generic; linear dispersion; linear broadcast; linear multicast. These four classes of linear network codes possess properties of decreasing strength.
In most health care systems, doctors act as gatekeepers to patients requiring “referred” services such as pharmaceuticals, tests and procedures. With the rising costs of such services, many third-party purchasers of health care are focussing on this gate keeping role of doctors.
Many purchasers have introduced supply-side cost sharing which imposes financial penalties on doctors for utilizing referred services, with the objective of limiting the utilization of referred services to patients for whom the benefit will outweigh the cost. Although imposing such schemes may result in more cost effective use of referred services, it also creates a potential agency problem for the
patient.
A conventional life annuity enables an individual to convert a stock of wealth (paid to a life insurer in a single premium) into an income that is received with certainty until the end of life. The advantage of such an annuity is that it insures the individual against out-living their wealth in the event of living longer than expected. Annuities represent the decumulation phase of a Defined Contribution (DC) pension scheme, and have been available in a variety of contexts since Roman times. They are of increasing importance in the UK because they form a large and growing part of the pension system.
As recently as a hundred years ago, nearly all workers would expect to earn a wage for almost their entire life and would usually only withdraw from the labour force as they became unable to work due to ill-health. Throughout the 20th Century this has gradually been replaced by a model whereby individuals stop working some time before the end of their life and while still relatively healthy. In many cases this long period of retirement would have been financed by a Defined Benefit (DB) occupational pension scheme, which involved the employer, albeit indirectly, continuing to pay a pension to the retired worker.
