Engineering Costs and Production Economics最新文献

In the international co-operative knockdown production systems (ICKDPS), the transportation lead time to procure component parts is much longer than actual production lead time. Therefore, in designing an ordering system for the ICKDPS, it is necessary to decide an adequate buffer capacity in order to improve the system reliability for the transportation lead time. In this paper, we develop a new pull type ordering system, based on the concepts of just-in-time production systems, which incorporates a backorder function which modifies the back-log carried over from the last period, and includes two types of buffer capacities, that is, safety stock and emergency delivery for the ICKDPS. By trading off these two types of buffer capacities, we develop a way of determining an economical safety stock level and emergency delivery rate which will assure system performance reliability to any pre-determined level.

In this paper a new methodology for state- and utility-level analysis of the cost and regional economic impacts of strategies for lowering utility SO₂ emissions is discussed and applied to the state of Ohio. The methodology is based upon probabilistic production costing and economic input-output analysis. The model considers the entire range of potential control strategies from a systems perspective and develops trade-off curves between the costs of electricity and the production of SO₂ emissions. This approach to the U.S. acid rain problem focuses on utility planning, coal-field employment, and economic impact assessment of proposed U.S. Congressional legislation.

The paper initially reviews uncertainties involved in evaluating acid rain control programs and discusses modeling techniques that have been used in the past. Five specific aspects of the Bush Administration 's proposed amendments to the U.S. Clean Air Act are investigated: hardware retrofits, energy conservation, industrial sources of SO₂, credits for NO_x reductions, and emissions banking. The paper concludes with an example of a non-inferior set generated by the model.

The proposed new maintenance management software differs from most currently available software in two ways. Firstly, it would provide automatic lateral data transfer to financial, stores, production control and quality control systems. Secondly, it is proposed to use data feedback and O.R. to continually review preventive and surveillance schedules.

In this paper a procedure is given for determining the economic ordering policy for a product for which the supplier has offered a reduction in price during a given specified period. The demand for the product is assumed to be constant over an infinite time horizon. An example is given to illustrate this method.

This paper explores a class of dynamic cost models that are designed for made-to-order production and are particularly applicable to the airframe industry. In these models we use optimal control theory to describe the time paths of resource use and production rate. The analytic solution for the most general specification of the model is unknown, however the imposition of a restriction on the relation between production rate and experience rate leads to a straightforward solution. The model implies that there exists an optimal trade-off between learning and production rate during the life of a program and that production rate should be changing throughout the life of the program in order to minimize cost. The model is compared with the learning curve, and the applicability of the model is explored by performing various parametric sensitivity analyses. The model's behavior is consistent with the dynamics of actual made-to-order production programs.

The inventory control system of a firm operating under Marshallian market conditions is developed as part of an optimal production planning problem. The control process is analyzed through the differences between the paths of supply and demand prices that lead to variations in the path of unplanned inventory accumulation. From the solution to the optimal production plan problem, the supply price is computed as a shadow price of output from the shadow prices of the inputs. The production planning problem is formulated with embodied and disembodied technological parameters. The firm 's inventory control system is then analyzed from the conditions of its internal cost, market power and changes in demand relative to capacity.

This paper examines the techniques and models for allocation of an optimum number of spare parts and modules at different levels of maintenance of a hierachical structure, in order to maximize system availability and minimize the costs and delay supply downtime. Computer programmes have been developed for calculating the optimum spares allocation for two and three maintenance levels. The approach to calculate spare parts allocation has been generalized by introducing repairable-parts modules into the model. A numerical example illustrates the influence of the maintenance policy on the efficiency of the maintenance system.

This paper presents 0–1 Mixed Integer Programming model for the nonlinear multiproduct Cost-Volume-Profit analysis, which relaxes the assumptions of linear revenue-cost functions and constant fixed cost. In this model, nonlinear revenue and cost functions are approximated by piecewise linear functions, and the joint fixed cost function is represented by a step-increment function. With these features, the required capacity level and the optimal product mix could be determined simultaneously. A hypothetical example, illustrating the model, is presented together with the profit-maximization solution, the breakeven solution, and the target-profit solutions.