We characterize the first hardware implementation of a selforganizing map algorithm based on axon migration. A population of silicon growth cones automatically wires a topographic mapping by migrating toward sources of a diffusible guidance signal that is released by postsynaptic activity. We varied the diffusion radius of this signal, trading strength for range. Best performance is achieved by...

This paper reviews statistical methods for inferring population history from mitochondrial mismatch distributions and extends them to the case of geographically structured populations. Inference is based on a geographically structured version of the coalescent algorithm that allows for temporal variation in population size, in the number of subdivisions, and in the rate of migration between sub...

Implementations of parallel genetic algorithms (GAs) with multiple populations are common, but they introduce several parameters whose effect on the quality of the search is not well understood. Parameters such as the number of populations, their size, the topology of communications, and the migration rate have to be set carefully to reach adequate solutions. This paper presents models that pre...

Implementations of parallel genetic algorithms (GAs) with multiple populations are common , but they introduce several parameters whose eeect on the quality of the search is not well understood. Parameters such as the number of populations, their size, the topology of communications, and the migration rate have to be set carefully to reach adequate solutions. This paper shows how to predict the...

the purpose of this descriptive correlational study was to investigate the tendency level of youth in rural areas of kermanshah township to migration, and to determine the influencing factors. the statistical population for the study was constituted of the rural boys (15-28 years) of kermanshah township (n= 17544). a multistage sample of rural youth was selected (n=291). the findings indicated ...