Abs t rac t . In this paper we introduce an Ant Colony Optimisation (ACO) algorithm for the Shortest Common Supersequence (SCS) problem, which has applications in production system planning, mechanical engineering and molecular biology. The ACO algorithm is used to find good parameters for a heuristic for the SCS problem. An island model with several populations of ants is used for the ACO algo...

This paper deals with a preventive maintenance strategy optimization correlated to production for a manufacturing system made by several parallel machines under lease contract. In order to minimize the total cost of production and maintenance by reducing the production system interruptions due to maintenance activities, a correlated group preventive maintenance policy is developed using the gra...

This paper considers a continuous-review, single-product production-inventory system with a constant replenishment rate, compound Poisson demands and lost-sales. Two objective functions that represent metrics of operational costs are considered: (1) the sum of the expected discounted inventory holding costs and lost-sales penalties, both over an infinite time horizon, given an initial inventory...

Background: This study quantified the effect of four popular culture media in a biodiesel production study on the qualitative and quantitative lipid content, dry biomass, and lipid productivity of Nannochloropsis oculata. Methods: Culture of microalgae was done separately in Walne, F/2, Sato, and TMRL media. In the logarithmic and stationary growth phases, biomass production and lipid accumulat...

I acid is an important building block for the chemical industry. Currently, Aspergillus terreus is the main organism used for itaconic acid production. Due to the enormous citric acid production capacity of Aspergillus niger, this host is investigated as a potential itaconic acid production host. Several strategies have been tried so far: fermentation optimization, expression of cis-aconitate d...

Natural gas from organic rich shales has become an important part of the supply of natural gas in the United States. Modern drilling and stimulation techniques have increased the potential and profitability of shale gas reserves that earlier were regarded as unprofitable resources of natural gas. The most prominent property of shale gas reservoirs is the low permeability. This is also the reaso...

effect of different ratios of sucrose to fruit concentrate (orange and sour cherry), level of cacl2 (0-2%) and storage time (0-90 days) on physicochemical properties of candied apples were investigated using of a combined design. different quality indices such as total sugars content, ascorbic acid, color attribute (chroma) and overall acceptance were modeled and then multiobjective optimizatio...