Chebyshev approximation of functions of two variables by a rational expression with interpolation

A method for constructing a Chebyshev approximation by a rational expression with interpolation for functions of two variables is proposed The idea of the method is based on the construction of the ultimate mean-power approximation in the norm of space Lp at p° . An iterative scheme based on the least squares method with two variable weight functions was used to construct such a Chebyshev approximation. The results of test examples confirm the effectiveness of the proposed method for constructing the Chebyshev approximation by a rational expression with interpolation.

A power approximation for the Kenward and Roger Wald test in the linear mixed model

We derive a noncentral F power approximation for the Kenward and Roger test. We use a method of moments approach to form an approximate distribution for the Kenward and Roger scaled Wald statistic, under the alternative. The result depends on the approximate moments of the unscaled Wald statistic. Via Monte Carlo simulation, we demonstrate that the new power approximation is accurate for cluster randomized trials and longitudinal study designs. The method retains accuracy for small sample sizes, even in the presence of missing data. We illustrate the method with a power calculation for an unbalanced group-randomized trial in oral cancer prevention.

DETERMINATION OF INVENTORY PERIODIC REVIEW POLICY (R, s, S) USING POWER APPROXIMATION METHOD FOR MINIMIZE TOTAL INVENTORY COST IN PT. OPQ

PT. OPQ is a company engaged in the automotive manufacturing industry. The company produces bolts for the safety area, it is related to the lower body of the four-wheeled vehicle. PT. OPQ was established in 2014 and today has already been the supplier for several major automotive companies in Indonesia. The demand of PT OPQ that must be fulfilled is increasing as the amount of consumer is increasing too. Due to the high demand, so the raw material stockout occurs. This make the company's service level is below the standard. This study involved 48 sku of material raw materials that have normal distributed demand. Inventory policy applied in this research is periodic review (R, s, S) with the aim to minimize total cost of inventory and improve service level of company. The result of this research was found to decrease total inventory cost by 15% with the value of existing inventory cost Rp1.100.879.479,- to Rp 936.061.349,- . In addition, service level at PT. OPQ has increased with the value of existing conditions 85% to 99%.

DETERMINATION OF INVENTORY PERIODIC REVIEW POLICY (R, s, S) USING POWER APPROXIMATION METHOD FOR MINIMIZE TOTAL INVENTORY COST IN PT. OPQ

OPQ is a company engaged in the automotive manufacturing industry. The company produces bolts for the safety area, it is related to the lower body of the four-wheeled vehicle. PT. OPQ was established in 2014 and today has already been the supplier for several major automotive companies in Indonesia. The demand of PT OPQ that must be fulfilled is increasing as the amount of consumer is increasing too. Due to the high demand, so the raw material stockout occurs. This make the company's service level is below the standard. This study involved 48 sku of material raw materials that have normal distributed demand. Inventory policy applied in this research is periodic review (R, s, S) with the aim to minimize total cost of inventory and improve service level of company. The result of this research was found to decrease total inventory cost by 15% with the value of existing inventory cost Rp1.100.879.479,- to Rp 936.061.349,- . In addition, service level at PT. OPQ has increased with the value of existing conditions 85% to 99%. Keywords—Raw Material, Periodic Review, Probabilistic, Service Level, Stock out

Influence of Tempering Temperatures on Magnetoelastic Relaxation Behavior of 30KH13 Steel

Magnetoelastic tests of 30KH13 (30X13) steel were carried out under cyclic loadings. The article focuses on the property of magnetoelastic power relaxation of remanent magnetization. With the load amplitude increasing, complexes of power approximation coefficients reflect typical mechanical loads at various tempering temperatures.

AN OPTIMAL ORDER QUANTITY OF SPARE PARTS TO MINIMIZE TOTAL INVENTORY COST USING PERIODIC REVIEW APPROACH (R,s,S) METHOD IN PT XYZ BANDUNG

The availability of spare parts is very crucial thing for manufacturing company in order to support the continuity of production activities. PT XYZ is a manufacturing company which produces thread into fabric. In this case, inventory control of spare part is not properly managed. Inventory position of spare parts in warehouse is always more than inventory policy of the company itself or called overstock which causes total inventory cost is always high. Company only consider on the order fulfillment of spare parts to prevent downtime on the machine that increase performance of production. Hence, order quantity of spare parts is always excessive or not optimal. In this research, global inventory policy conducted in order to minimize total inventory cost is periodic review approach (R, s, S) method. This inventory policy will be calculated using power approximation and obtained total saving cost of holding cost by 31 % while total saving cost of order cost decreased by 7 %. Overall, total inventory cost minimized by 7 % or equal to Rp138.902.742. Keywords—Inventory, Overstock, Spare Parts, Periodic Review, Power Approximation