Conference papers (refereed only)

Emblemsvåg, J. and B. A. Bras (1995). “The Use of Activity-Based Costing, Uncertainty and Disassembly Action Charts in Demanufacture Cost Assessments”. 1995 ASME Advances in Design Automation Conference, Ed., Boston, Massachusetts, ASME, Sept 17-20, 1995.

Abstract: In this paper, the development of an Activity-Based Cost (ABC) model is presented for use in design for demanufacture under the presence of uncertainty. Demanufacture is defined as the process opposite to manufacturing involved in recycling materials and product components after a product has been taken back by a company. The crux in developing an ABC model is to identify the activities that will be present in the demanufacturing process of a product, and afterwards assign reliable cost drivers and associated consumption intensities to the activities. Uncertainty distributions are assigned to the numbers used in the calculations, representing the inherent uncertainty in the model. The effect of the uncertainty on the cost and model behaviour are found by employing a numerical simulation technique. The additional use of disassembly action charts allows the influence of the uncertainty to be traced through the cost model to specific demanufacture process and product design parameters.


 

Emblemsvåg, J. and B. Bras (1997). “An Activity-Based Life-Cycle Assessment Method”. 1997 ASME Design Engineering Technical Conference, Sacramento, California, American Society of Mechanical Engineers, Sept 14 – 17, 1997.

Abstract: In this paper, a new activity-based method for the concurrent assessment and tracing of costs, energy consumption and waste generation for usage in Life-Cycle Design is presented. The method is based on Activity-Based Costing (ABC). By utilizing ABC we are able to assess and trace accurately overhead – and direct costs, energy and waste generation.. The inherent uncertainty is modeled in terms of fuzzy numbers, but solved numerically using the Monte Carlo simulation technique, which allows us to perform a sensitivity analysis. This enables us to not only estimate the costs, energy consumption and waste generation, but also trace the largest contributors. The capability to trace the contributors is perhaps the most significant feature – especially when the method is employed for design. To illustrate the usage of this method, a simple case study is provided in which we explore the life-span costs, energy consumption and waste generation of a oil/gas exploration platform supply vessel operating in the North Sea.


Emblemsvåg, J. and B. Bras (1998). “Financial Analysis, Critical Assumption Planning and Uncertainty in Product Development”. 1998 International Conference on Achieving Excellence in New Product Development and Management, Atlanta, Georgia. Product Development & Management Association (PDMA).

Abstract: Uncertainty analysis and critical assumption planning are vital activities in product development, and traditionally this is done by assessing risk and manually varying the model parameters. This approach is inaccurate and laborious. Monte Carlo methods with sensitivity analyses reduce these problems significantly because uncertainty is modelled more realistically and the impact of uncertainty on the performance measures is assessed. A simple financial analysis of services provided by Farstad Shipping to oil companies illustrates the approach.


 

Emblemsvåg, J. and B. A. Bras (1998). “ISO 14000 and Activity-Based Life-Cycle Assessment in Environmentally Conscious Design and Manufacturing: A Comparison”. 1998 ASME Design Engineering Technical Conference, Atlanta, Georgia, American Society of Mechanical Engineers, Sept 14 – 17, 1998.

Abstract: As a part of the new ISO 14000 environmental management standard, standards for conducting Life-Cycle Assessments (LCAs) are proposed. In this paper we compare these standards to Activity-Based LCA by using a toy manufacturer called WagonHo!, Inc. as an implementation test case. In this case study, both economical and environmental assessments are made of the product- and process designs. Because the ISO 14000 LCA does not incorporate costing methods, we have used Variable Costing combined with standard times. Activity-Based LCA, on the other hand, combines an Activity-Based Costing (ABC) like method and activity-based environmental impact assessment methods into a single method. The ISO 14000 and Activity-Based LCA are compared with respect to assessment accuracy and how well they indicate areas in need of redesign. Due to the need of short-term survival caused by a severe negative economic result, we will mainly look at process design and market strategies, because product design is a more long-term effort. It is shown that in this case, Activity-Based LCA is superior to ISO 14000 based LCA – possibly in most situations.