arXiv subjects

Christos H. Skiadas

Publications and source records attributed to Christos H. Skiadas.

6 recordsLinked to original sources

arXiv2012

A Method for Estimating the Total Loss of Healthy Life Years: Applications and Comparisons in UK and Scotland

We propose a method of estimating the Total Loss of Healthy Life Years based on the first exit time theory for a stochastic process, the resulting Health State Function and the Deterioration Function estimated as the curvature of the health state function. We have done many applications in UK and Scotland and Sweden supporting our theory. Furthermore it was proven that both the WHO and EU estimates of the healthy life expectancy can result from our method. The WHO system takes into account the severe and moderate causes in estimating the loss of healthy life years; instead the EU system calculates the total loss of healthy life years. For both cases our methodology provides both estimators from only death and population data. The advantages of our method are straightforward. We do not need survey data to make the calculations. The resulting estimates should be used to test and improve the existing survey based methodologies. While the WHO and EU systems tend to approach each other differences continue to appear based on the methodology of the related surveys and the analysis of data. Two main schools are working to these directions one based on USA the Institute for Health Metrics and Evaluation (IHME) headed by Christopher J.L. Murray and contributors in all over the world and the European Health and Life Expectancy Information System (EHLEIS) with Jean-Marie Robine and a team from the EU member states. Keywords: Deterioration, Loss of healthy years, HALE, DALE, World Health Organization, WHO, European Union, EU, EHEMU, IHME, EHLEIS, Healthy life expectancy, Life expectancy.

q-bio.PE↗

arXiv2012

Estimating the Healthy Life Expectancy from the Health State Function of a Population in Connection to the Life Expectancy at Birth

Following our previous works on the health state of a population and the related health state function we proceed in developing a method to estimate the Healthy Life Expectancy in connection to the relative impact of the Mortality Area in the health state function graph. The resulting tools are applied to the data sets for 1990, 2000 and 2009 for the Countries of the World Health Organization (WHO). The application is done in the Excel Chart and it is ready to be used for other time periods. The results are compared with the estimates presented in the WHO report for 2000 showing a good relationship between the estimates of the two methods. However, our proposed method, not based on collection of data for diseases and other causes affecting a healthy life, is more flexible. We can estimate the healthy life years from various time periods when information related to diseases is missing. Keywords: Health state function, Healthy life expectancy, Deterioration, Loss of healthy years, HALE, DALE, World Health Organization, WHO

q-bio.PE↗

arXiv2012

The Health State Function, the Force of Mortality and other Characteristics resulting from the First Exit Time Theory applied to Life Table Data

In this paper we summarize the main parts of the first exit time theory developed in connection to the life table data and the resulting theoretical and applied issues. Several new tools arise from the development of this theory and especially the Health State Function and some important characteristics of this function. Special attention has being done in the presentation of the health state function along with the well established theory for the Force of Mortality and the related applications as are the life tables and the estimation of life expectancies. A main part of this work is the formulation of the appropriate non-linear analysis program including a model which provides an almost perfect fit to life table data. This model, proposed in 1995 is now expanded as to include the mortality excess for the age group from 15-30 years. A version of the program is given in Excel and provided at the website: http://www.cmsim.net

q-bio.PE↗

arXiv2011

Life Expectancy at Birth, Estimates and Forecasts in the Netherlands (Females)

In this paper we explore the life expectancy at birth in the Netherlands by based on a recent theory and a new methodology but also a classical theory of fitting and forecasting. We use the data from 1850 to 2006 provided by the Human Mortality Database (HMD) for the annual deaths per year of age and the structure of the population per year of age. We apply the IM first exit time model which includes also the infant mortality by using the appropriate non-linear regression analysis program that we have developed in Excel. We provide all the related material from the website: http://www.cmsim.net

q-bio.PE↗

arXiv2007

Chaos in Simple Rotation-Translation Models

The chaotic properties of simple two-dimensional rotation-translation models are explored and simulated. The models are given in difference equation forms, while the corresponding differential equations systems are studied and the resulting trajectories in the plane are explored and illustrated in the computer experiments done. Characteristic patterns, egg-shaped forms and central chaotic bulges are present when particles are introduced in the rotating system. The resulting forms and chaotic attractors mainly depend on the form of the nonlinear function expressing the rotation angle. Several cases are studied corresponding to a central force rotation system.

nlin.CD↗

arXiv2006

Exploring and Simulating Chaotic Advection:A Difference Equations Approach

This paper explores the chaotic properties of an advection system expressed in difference equations form. In the beginning the Aref's blinking vortex system is examined. Then several new lines are explored related to the sink problem (one central sink, two symmetric sinks, eccentric sink and others). Chaotic forms with or without space contraction are presented, analyzed and simulated. Several chaotic objects are formulated especially when special rotation angles or a complex sinus rotation angle are introduced in the rotation-translation difference equations. Very interesting chaotic forms arise when elliptic rotation-translation equations are applied. The simulated chaotic images and attractors express several vortex-like forms resulting in various situations and especially in fluid dynamics.

nlin.CD↗