Systems Aspects of Health Planning

The Conference, "Systems Aspects of Health Planning," which this book describes, touched upon many important themes of IIASA: how interdisciplinary systems science should best be organized and directed; how analytic experts and real world practitioners should combine efforts to address most effectively the difficult policy problems of current relevance; and how leading representatives of many nations--in socialist and non-socialist lands--might learn from the experiences of one another. The book may be valuable for a number of possible reader purposes. On the most evident level, it presents in its papers a series of good examples of what systems analysis is and how it should be applied within the context of health system planning. The student of comparative health systems will find the book rewarding for its description of alternative systems and the rationale which underline them. These descriptions are invaluable as candid statements--and critical self-analysis--by the very people who make the systems work. The English language literature has been regrettably deficient in descriptions of health systems in the Eastern countries written from the viewpoint of their managers. On still another plane, the book may be read with attention upon the dialogue that followed paper presentations. Here especially can be seen frank discussions of the issues with highest importance to the analysis of health systems in the mid-1970s

Fast evaluation of appointment schedules for outpatients in health care

We consider the problem of evaluating an appointment schedule for outpatients in a hospital. Given a fixed-length session during which a physician sees K patients, each patient has to be given an appointment time during this session in advance. When a patient arrives on its appointment, the consultations of the previous patients are either already finished or are still going on, which respectively means that the physician has been standing idle or that the patient has to wait, both of which are undesirable. Optimising a schedule according to performance criteria such as patient waiting times, physician idle times, session overtime, etc. usually requires a heuristic search method involving a huge number of repeated schedule evaluations. Hence, the aim of our evaluation approach is to obtain accurate predictions as fast as possible, i.e. at a very low computational cost. This is achieved by (1) using Lindley's recursion to allow for explicit expressions and (2) choosing a discrete-time (slotted) setting to make those expression easy to compute. We assume general, possibly distinct, distributions for the patient's consultation times, which allows us to account for multiple treatment types, as well as patient no-shows. The moments of waiting and idle times are obtained. For each slot, we also calculate the moments of waiting and idle time of an additional patient, should it be appointed to that slot. As we demonstrate, a graphical representation of these quantities can be used to assist a sequential scheduling strategy, as often used in practice

Linear independence of root equations for M/G /1 type Markov chains

There is a classical technique for determining the equilibrium probabilities of M/G/1 type Markov chains. After transforming the equilibrium balance equations of the chain, one obtains an equivalent system of equations in analytic functions to be solved. This method requires finding all singularities of a given matrix function in the unit disk and then using them to obtain a set of linear equations in the finite number of unknown boundary probabilities. The remaining probabilities and other measures of interest are then computed from the boundary probabilities. Under certain technical assumptions, the linear independence of the resulting equations is established by a direct argument involving only elementary results from matrix theory and complex analysis. Simple conditions for the ergodicity and nonergodicity of the chain are also given.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47619/1/11134_2005_Article_BF01245323.pd

Sliding blocks with random friction and absorbing random walks

With the purpose of explaining recent experimental findings, we study the distribution $A(\lambda)$ of distances $\lambda$ traversed by a block that slides on an inclined plane and stops due to friction. A simple model in which the friction coefficient $\mu$ is a random function of position is considered. The problem of finding $A(\lambda)$ is equivalent to a First-Passage-Time problem for a one-dimensional random walk with nonzero drift, whose exact solution is well-known. From the exact solution of this problem we conclude that: a) for inclination angles $\theta$ less than \theta_c=\tan(\av{\mu}) the average traversed distance \av{\lambda} is finite, and diverges when $\theta \to \theta_c^{-}$ as \av{\lambda} \sim (\theta_c-\theta)^{-1}; b) at the critical angle a power-law distribution of slidings is obtained: $A(\lambda) \sim \lambda^{-3/2}$. Our analytical results are confirmed by numerical simulation, and are in partial agreement with the reported experimental results. We discuss the possible reasons for the remaining discrepancies.Comment: 8 pages, 8 figures, submitted to Phys. Rev.

Statistical Methods in Biology

xiii,255 hal,;ill,;20 c