in recent years, iran has experienced high level depreciation of the nominal exchange rate (ner). the ultimate effects of such depreciation on iranian families’ welfare and income distribution have been a challenging issue among policymakers and researchers. accordingly, this study evaluates the economic effects of ner depreciation on the rice market, using spatial price equilibrium model. the ...

in accordance with the iranian government intention toward two step forward elimination of energy subsidies policy in coming years, we focus in this study on the extent by which the corresponding raising costs will be distributed across the livestock sector and how they affected food security. for this purpose, scenario of increasing energy prices and improving productivity at vertical and hori...

warranty as a kind of service contract today plays a role key in business and legal transactions. in this paper, we present a manufacturer, an agent and a customer's model under different service contracts suggestions. the manufacturer's profit is maximized by determining sale price, warranty period and warranty price. in addition we obtain optimal maintenance cost or repair cost for ...

this paper is concerned with global analysis of a delay sveir epidemiological model in a population of varying size. by using lyapunov stability method and lasalle’s invariance principle for delay systems, we prove that when there is no endemic equilibrium, the disease free equilibrium is globally asymptotically stable, otherwise the endemic equilibrium is globally stable.