a three stage production system is considered in this paper. there are two stages to fabricate and ready the parts and an assembly stage to assembly the parts and complete the products in this system. suppose that a number of products of different kinds are ordered. each product is assembled with a set of several parts. at first the parts are produced in the first stage with parallel machines a...

‎this paper proposes a multi-supplier multi-product inventory model in which the suppliers have unlimited production capacity, allow delayed payment, and offer either an all-unit or incremental discount. the retailer can delay payment until after they have sold all the units of the purchased product. the retailer’s warehouse is limited, but the surplus can be stored in a rented warehouse at a...

cellular manufacturing system (cms) is highly important in modern manufacturing methods. given the ever increasing market competition in terms of time and cost of manufacturing, we need models to decrease the cost and time of manufacturing. in this study, cms is considered in condition of dynamic demand in each period. the model is developed for facing dynamic demand that increases the cost of ...

background: functional electrical stimulation (fes) is the most commonly used system for restoring functions after spinal cord injury (sci). objective: in this study we investigated feedback pid and feedforward-feedback p-pid controllers for regulating the elbow joint angle. methods: the controllers were tuned based on a nonlinear muculoskeletal model containing two links, one joint with one de...

the exponential growth of the flow of goods and passengers, fragility of certain products and the need for the optimization of transport costs impose on carriers to use more and more multimodal transport. in addition, the need for intermodal transport policy has been strongly driven by environmental concerns and to benefit from the combination of different modes of transport to cope with the in...

in the current work, different methods for optimization of turbine blade internal cooling are investigated, to achieve higher cyclic efficiency and output power for a typical gas turbine. a simple two-dimensional model of c3x blade is simulated and validated with available experimental data. the optimization process is performed on this model with two different methods. the first method is a po...

in this study, we focused on the gait of parkinson’s disease (pd) and presented a gray box model for it. we tried to present a model for basal ganglia structure in order to generate stride time interval signal in model output for healthy and pd states. because of feedback role of dopamine neurotransmitter in basal ganglia, this part is modelled by “elman network”, which is a neural network stru...

optimizing the database queries is one of hard research problems. exhaustive search techniques like dynamic programming is suitable for queries with a few relations, but by increasing the number of relations in query, much use of memory and processing is needed, and the use of these methods is not suitable, so we have to use random and evolutionary methods. the use of evolutionary methods, beca...