A hybrid genetic algorithm based on Pareto was proposed and applied to the flexible job shop scheduling problem (FJSP) with bi-objective, and the bi-objective FJSP optimization model was built, where the make-span and the production cost were concerned. The algorithm embeds Pareto ranking strategy into Pareto competition method, and the niche technology and four kinds of crossover operations are used in order to promote solution diversity. Pareto filter saves the optimum individual occurring in the course of evolution, which avoids losing the optimum solutions. This hybrid genetic algorithm reasonably assigns the resources of machines and workers to jobs and achieves optimum on some performance. In this paper, the influence of the proportion of workers and machines on the scheduling result is researched on the basis of the hybrid genetic algorithm and the result is in accord with other researchers. In conclusion, the algorithm proposed in this paper is available and efficient.
As a purpose of developing micro-actuators driven by liquid crystals, transient behaviors of a nematic liquid crystal between two parallel plates under an electric field have investigated numerically by using the Leslie-Ericksen theory. Twist angle has been selected as computational parameters. Imposition of an electric field on a liquid crystal induces backflow whose profile and magnitude depend strongly on the twist angle of the director. When the twist angle is 0 degree, the induced flow is planar, and with increasing of the twist angle, the flow has an out of plane component, and finally the profile becomes unidirectional when the twist angle reaches 180 degrees.
A hybrid genetic algorithm based on Pareto was proposed and applied to flexible job shop scheduling problem (FJSP) with multi-objective, and the multi-objective FJSP optimization model was built, where the make-span and the machine utilization rate were concerned. The algorithm embeds Pareto ranking strategy into Pareto competition method. The operation-based encoding and an active scheduling decoding method are employed. In order to promote solution diversity, the niche technology and many kinds of crossover operations are used. Pareto filter saves the optimum individual occurring in the course of evolution, which avoids losing the optimum solutions. Three simulation experiments are carried out to illustrate that the proposed method could solve multi-objective job shop scheduling problem effectively.
As a purpose of developing new micro-actuator driven by the liquid crystal flow, transient behaviors of a nematic liquid crystal between two parallel plates are computed with parameter of twist angle. The Frank and Leslie-Ericksen theory were used. When the twist angle is 0 deg, the induced flow is planar, and when the twist angle is not 0 deg, the flow has a out of plane component. The twist angle has little effect to the time characteristics of the flow. In the experiment, the applied voltage of 5 was used, and the results are in agreement with the calculation results.
Hydro-turbine generator unit turning test is a key step to check the installation quality of the shafting system. The unit turning data is very important for bearing clearance adjustment. The traditional unit turning test and bearing clearance adjustment are based on a condition of that the spindle turning orbit is an approximate circle. It is simple to be used in the field operation and applicable to the most units. The trajectory of the turning orbit shows irregular shape when the spindle has a certain part of the flaw. If the traditional method is used for the unit turning and adjusting the bearing clearance, this may cause the eccentricity of three guide bearing bushes and uneven of the bearing clearance. The unit may appear a high temperature or large swing phenomenon after its commission. Seriously the unit may be burned and permanent damage. To solve this problem, this paper proposed a new method to calculate a minimum rotation space of the shaft in the bearing for each guide bearing clearance according to a geometric algorithm. Using the new method, according to the minimum circumscribed circle of the turning axis locus and final position of the turning spindle after unit turning, the bearing clearances corresponding to each turning number on the shaft can be calculated precisely. And then the bearing radial position is distributed properly so that the bearing is in the centre of rotation to the centre of the concentric circle. Therefore, the specific value of each bearing clearance adjustment is obtained. Site testing results show that using the new method the high temperature and large adjustment gap caused by using the traditional method can be avoided. Thus, the hydro-turbine generator unit operating stability is improved.
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