One of the surface mining methods is open-pit mining,by which a pit is dug to extract ore or waste downwards from the earth’s surface.In the mining industry,one of the most significant difficulties is long-term produ...One of the surface mining methods is open-pit mining,by which a pit is dug to extract ore or waste downwards from the earth’s surface.In the mining industry,one of the most significant difficulties is long-term production scheduling(LTPS)of the open-pit mines.Deterministic and uncertainty-based approaches are identified as the main strategies,which have been widely used to cope with this problem.Within the last few years,many researchers have highly considered a new computational type,which is less costly,i.e.,meta-heuristic methods,so as to solve the mine design and production scheduling problem.Although the optimality of the final solution cannot be guaranteed,they are able to produce sufficiently good solutions with relatively less computational costs.In the present paper,two hybrid models between augmented Lagrangian relaxation(ALR)and a particle swarm optimization(PSO)and ALR and bat algorithm(BA)are suggested so that the LTPS problem is solved under the condition of grade uncertainty.It is suggested to carry out the ALR method on the LTPS problem to improve its performance and accelerate the convergence.Moreover,the Lagrangian coefficients are updated by using PSO and BA.The presented models have been compared with the outcomes of the ALR-genetic algorithm,the ALR-traditional sub-gradient method,and the conventional method without using the Lagrangian approach.The results indicated that the ALR is considered a more efficient approach which can solve a large-scale problem and make a valid solution.Hence,it is more effectual than the conventional method.Furthermore,the time and cost of computation are diminished by the proposed hybrid strategies.The CPU time using the ALR-BA method is about 7.4%higher than the ALR-PSO approach.展开更多
Tomato is one of the most widely produced and consumed vegetable crops in Ethiopia. It is not produced during the rainy season, mainly due to high disease pressure and low soil temperature. Therefore, an experiment wa...Tomato is one of the most widely produced and consumed vegetable crops in Ethiopia. It is not produced during the rainy season, mainly due to high disease pressure and low soil temperature. Therefore, an experiment was conducted to study the effect of different types of mulch （black and white plastic mulch as well as grass mulch） on early yield of tomato varieties （Miya ＆ Cochoro） under polyhouse growing condition at Bahir Dar during the rainy season in 2012. Treatments were arranged in 4 - 2 factorial combinations in randomized complete block design with three replications. One month old seedlings were transplanted on 8.4 m2 gross plots size （3 m x 2.8 m） at a spacing of 70 cm x 40 cm between rows and plants, respectively. Data recorded from plants found in the two middle rows of each plot. Di-ammonium phosphate （DAP） and Urea fertilizers were applied at the rate of 200 kg and 100 kg/ha, respectively. Sixteen plants were considered for data collection in each plot. White plastic mulch resulted in significantly （P 〈 0.05） earlier flowering, fruit setting and fruit maturity compared to other mulching materials. Varieties were also significantly different in days required to flowering, fruit setting and fruit maturity. Miya took significantly short period to flower, fruit set and fruit maturity compared to Cochoro variety. The effect of different mulch types on early fruit yield was found statistically significant. The highest early marketable fruit yield of 10.99 ton/ha and 10.54 ton/ha were recorded when Miya variety was grown with white and black plastic mulch, respectively. Therefore, use of white and black plastic mulches recommended for early tomato fruit yield.展开更多
文摘One of the surface mining methods is open-pit mining,by which a pit is dug to extract ore or waste downwards from the earth’s surface.In the mining industry,one of the most significant difficulties is long-term production scheduling(LTPS)of the open-pit mines.Deterministic and uncertainty-based approaches are identified as the main strategies,which have been widely used to cope with this problem.Within the last few years,many researchers have highly considered a new computational type,which is less costly,i.e.,meta-heuristic methods,so as to solve the mine design and production scheduling problem.Although the optimality of the final solution cannot be guaranteed,they are able to produce sufficiently good solutions with relatively less computational costs.In the present paper,two hybrid models between augmented Lagrangian relaxation(ALR)and a particle swarm optimization(PSO)and ALR and bat algorithm(BA)are suggested so that the LTPS problem is solved under the condition of grade uncertainty.It is suggested to carry out the ALR method on the LTPS problem to improve its performance and accelerate the convergence.Moreover,the Lagrangian coefficients are updated by using PSO and BA.The presented models have been compared with the outcomes of the ALR-genetic algorithm,the ALR-traditional sub-gradient method,and the conventional method without using the Lagrangian approach.The results indicated that the ALR is considered a more efficient approach which can solve a large-scale problem and make a valid solution.Hence,it is more effectual than the conventional method.Furthermore,the time and cost of computation are diminished by the proposed hybrid strategies.The CPU time using the ALR-BA method is about 7.4%higher than the ALR-PSO approach.
文摘Tomato is one of the most widely produced and consumed vegetable crops in Ethiopia. It is not produced during the rainy season, mainly due to high disease pressure and low soil temperature. Therefore, an experiment was conducted to study the effect of different types of mulch （black and white plastic mulch as well as grass mulch） on early yield of tomato varieties （Miya ＆ Cochoro） under polyhouse growing condition at Bahir Dar during the rainy season in 2012. Treatments were arranged in 4 - 2 factorial combinations in randomized complete block design with three replications. One month old seedlings were transplanted on 8.4 m2 gross plots size （3 m x 2.8 m） at a spacing of 70 cm x 40 cm between rows and plants, respectively. Data recorded from plants found in the two middle rows of each plot. Di-ammonium phosphate （DAP） and Urea fertilizers were applied at the rate of 200 kg and 100 kg/ha, respectively. Sixteen plants were considered for data collection in each plot. White plastic mulch resulted in significantly （P 〈 0.05） earlier flowering, fruit setting and fruit maturity compared to other mulching materials. Varieties were also significantly different in days required to flowering, fruit setting and fruit maturity. Miya took significantly short period to flower, fruit set and fruit maturity compared to Cochoro variety. The effect of different mulch types on early fruit yield was found statistically significant. The highest early marketable fruit yield of 10.99 ton/ha and 10.54 ton/ha were recorded when Miya variety was grown with white and black plastic mulch, respectively. Therefore, use of white and black plastic mulches recommended for early tomato fruit yield.
