an analysis of the stages of crop growth presents an important step in the improvement of production management. through growth analysis, planning for planting systems, fertilization, pruning operations, harvest time as well as obtaining economical yield can be more accessible. therefore, a development of mathematical models simulating plant growth would be helpful in improving crop management,...

A cover of a hypergraph is a collection of edges whose union contains all vertices. Let H = (V, E) be a k-uniform, D-regular hypergraph on n vertices, in which no two vertices are contained in more than o(D/e log D) edges as D tends to infinity. Our results include that if k = o(log D), then there is a cover of (1 + o(1))n/k edges, extending the known result that this holds for fixed k. On the ...

population in all countries plays a fundamental role in economic growth and economic development. but besides absolute size and growth rate of population, the more important factor will be “age structure” or “age distribution” of population, because it can be as source of many economical, social, and political challenges. in this research, we investigate effect of changes in population shares i...

There is a growing attention being placed on community networking and community informatics, due to the role both can play in building the Information Society. Hence, the issue of the sustainability of online communities becomes more and more relevant: multiple aspects – social, institutional and economical – have to be jointly analyzed to understand how and if a project is really worthwhile. I...

Along with the growth of Grid infrastructures, ubiquitous service provision and consumption has received wide attention in literature and practice. Although the number of available services rises rapidly, concepts and standards for an economical efficient service allocation remain in their infancy. Most proposed mechanisms lack of an interdisciplinary analysis that accounts for economical and t...

to day reaching a high economic growth rate is one of the main and important aim of any economic system. today the economists accept that economic stability is a necessary issue, but is not enough for the economic growth, while economic instability is one of the main elements, which restrict economic growth. the aim of this research is analysis of the effect of stability index of economy on eco...