Simulation Budget Allocation for Further Enhancing the Efficiency of Ordinal Optimization

Ordinal Optimization has emerged as an efficient technique for simulation and optimization. Exponential convergence rates can be achieved in many cases. In this paper, we present a new approach that can further enhance the efficiency of ordinal optimization. Our approach determines a highly efficient number of simulation replications or samples and significantly reduces the total simulation cost. We also compare several different allocation procedures, including a popular two-stage procedure in simulation literature. Numerical testing shows that our approach is much more efficient than all compared methods. The results further indicate that our approach can obtain a speedup factor of higher than 20 above and beyond the speedup achieved by the use of ordinal optimization for a 210-design example.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45045/1/10626_2004_Article_264696.pd

Ecological and economic importance of studying propagation techniques of common hawthorn Crataegus monogyna Jacq.

Climate change as a fact of global warming requires the development of different perspectives on the planning and implementation of sustainable forestry techniques. Increasing temperatures cause drought on a global basis. In connection with, this using drought tolerant species in afforestation work is of great importance. In recent years Crataegus L. species (hawthorn) are also involved in afforestation. One of these species, C. monogyna, is characterized by drought tolerance. Furthermore, C. monogyna is the most important non­wood forest product species of Turkey. Hawthorn is widely used in medicine (treatment of coronary heart diseases), and cosmetics industry, agriculture and animal husbandry and human nutrition. On the other hand, it is used in erosion control, afforestation, industrial energy resources and for landscaping. Economic and ecological contribution of hawthorn to the national economy is quite high. Therefore, determination of suitable generative and vegetative reproduction techniques and vast production of seedlings of hawthorn species are extremely important. The characteristics of generative and vegetative propagation of Crataegus are discussed. For generative propagation of hawthorn species, the most effective and suitable procedure is treatment of seeds in ash solution. For vegetative propagation in culture in vitro the growth induced by BA (benzyladenine) and IBA (indole butyric acid) hormones increases the rate of callus formation and rooting. The best grafting technique is that splicing

Proceedings of the 2002 Winter Simulation Conference

This paper describes an extension to the existing BSP Time Warp dynamic load-balancing algorithm to allow the management of interruption from external workload. Experiments carried out on a manufacturing simulation model using different partition strategies with and without interruption from external workload show that significant performance improvement can be achieved with external workload management