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Biomedical subjects

A Akkerman

Publications and source records attributed to A Akkerman.

9 recordsLinked to original sources
PubMed1996

A problem in household composition.

"Distinction made between household-persons and household-markers [the person who identifies the family or household as a unit] is formalized in the notion of nested populations. This leads to an extension of the Leslie model into a formulation of growth for both population and households. The extended model involves the matrix presentation of household composition where ratios of household-persons who are age 0, per household-marker, function as surrogate values for fertility rates. The extended model describes change over time in the distribution of population by age, and in the distribution of households by age of household-marker, or household-head. The model involves the inversion of a nonnegative matrix, and is feasible only if it yields, projected over time, nonnegative entries in vectors representing distribution of population by age, and distribution of household-heads by age. Conditions for the feasibility of the extended model are discussed, and a sufficient condition for feasibility over a single interval is identified." (SUMMARY IN FRE)

Age Distribution↗
PubMed1995

The urban household pattern of daytime population change.

"A matrix representation of places of residence and places of commuting destination in a metropolis, is coupled with evidence regarding spatio-temporal change in average household size. This approach allows the average number of persons per household who commute to be hierarchically ordered in a square matrix which shows attributes associated with a well-known class of matrices. Based on these attributes it is shown that any given spatial distribution of households implies a bounded range of vectors representing the spatial distribution of commuters.... The proposed methodology is applied to thirty four subareas throughout the city of Saskatoon, Saskatchewan."

Americas↗
PubMed1994

Sameness of age cohorts in the mathematics of population growth.

"Considering age groups as part of cohorts, implicit in LLM [a Leslie-Lotka finitist model], causes difficulty, manifested by the extensionality paradox. The proposition made here was that cohorts are empirical temporal entities, while age groups are theoretical entities, references only. Cohort is a multitude of persons born at the same time interval, throughout the totality of their lives. Age group, on the other hand, is a concept only, constituted by the notion of the age interval....A model of household and population growth based on the household composition matrix yields results that are inherently different from these of LLM."

Age Factors↗
PubMed1992

The relational structure of human services planning: an input-output analysis.

The relationship between human needs and human services can be quantified in terms of service standards and service units. A service standard is defined as the adopted norm for the minimum number of service units per person. The relationship between need, service (or care) and service standard is similar to the relationship between demand, supply and price in economics. Of particular interest in planning is the case where service units are given in terms of service providers per person. In a population where each person is considered to be a receiver of n categories of service and a provider of one category of service, the relationship between needs and services can further be presented in a service standard matrix. Examination of such a matrix shows that it fulfills a function analogous to the input-output matrix in economics. The principal eigen-vector of the ser-vice standard matrix expresses ratios of activity levels for a human service system in an equilibrium. Another, related equilibrium is identified for a human service system in which there are providers as well as nonproviders. Application of the two equilibria identifies optimum planning conditions for the provision of human services when service standards and population are known.

Alberta↗
PubMed1985

The household-composition matrix as a notion in multiregional forecasting of population and households.

"The household-composition matrix has been used in the past for single-region projection of population and households; here the application is expanded to multiregional projection of population and households. Geographic regions of residence are considered as household categories, and a household-composition matrix is constructed to indicate average numbers of persons by age per household, for each of the regions considered." The method is illustrated using data for the city of Edmonton, Canada. Changes over time due to population aging and to observed patterns of household mobility are considered. "These patterns are listed as six possible household mobility types, which in turn, are viewed as constraints within which population growth takes place. With the assumption that external net-migration to the regions, as a whole, is known for a projected period, an iterative procedure is offered to estimate future population by age and region, as well as future number and average size of households by region."

Age Distribution↗