What-if Capabilities Research Articles

Activity-based costing revisited by managerial economics logic

This paper identifies a number of differences in the treatment of costs and expenditures in activitybased costing (ABC) and a management accounting system based on the managerial economics model.At present, ex ante ABC models incorporating a resource consumption model and a resource spending model with what-if capabilities are recommended for activity-based budgeting in order to make betterinformed strategic and operational decisions. Using a numerical example, the paper demonstrates the resulting cost distortions in ex ante ABC models and their profitability segments when costs are nonlinear and in situations where opportunity costs are relevant. The paper also shows how these distortions can be avoided in a budget layout based on managerial economics

A neural network approach for predicting the structural behavior of concrete slabs

In this paper the use of a nontraditional technique, neural networks, has been investigated as a means to develop efficient predictive models of the structural behavior of concrete slabs. The applicability of neural networks within the realm of structural analysis is first reviewed, along with their state-of-the-art applications and research efforts. Four neural networks have then been developed to model the load-deflection behavior of concrete slabs, the final crack-pattern formation, and both the reinforcing-steel and concrete strain distributions at failure. The four neural networks were trained and tested using the experimental results of 38 full-scale slabs. Details regarding data modeling, neural network training, and performance evaluation are described. Using the developed networks, a spreadsheet tool for the structural analysis of concrete slabs was developed with a simple interface, automated predictions, and what-if capabilities. The developed tool is useful for teaching purposes and for reasonable prediction of the behavior of concrete slabs without additional experimental testing.Key words: neural networks, structural analysis, reinforced concrete, load-deflection, crack pattern, artificial intelligence, concrete slabs.

Managing uncertainty in time-critical plan evaluation

In complex real-world domains, uncertainty in predicting the results of plan execution drives the evaluation component of the planning cycle to explore a combinatorial explosion of alternative futures. This evaluation component is critical in evaluating the feasibility, strengths and weaknesses of a proposed plan. In time critical situations the planner is thus faced with a trade-off between timeliness and evaluation completion. Furthermore, a human planner is faced with the additional problem of evaluation credibility when using fast automatic evaluation in a complex and uncertain domain. An approach to handling these problems of time-criticality, uncertainty, and credibility is explored using the wargaming component of the military operational planning cycle. The Semi-Automated Forces Wargamer has been developed using two techniques. The first technique integrates procedural representations of plans and intentions with heuristic representations of simulated probabilistic execution. This facilitates the simulated execution of plans with multiple worlds corresponding to the possible results of actions taken in the real and uncertain world. The second provides a what-if capability via a tree representation of the possible combat outcomes. This provides the user with a tool for intelligent and focussed exploration of the space of possible outcomes to the plan. These techniques combine to generate a manageable and useful subset of the space of simulated plan results from which the user can apply human expertize to guide plan exploration.

An execution-backtracking approach to debugging

Spyder, a system for selective checkpointing of computational sequences, is presented. It lets users backtrack from checkpoints without the need to reexecute the program to reach recent prior states. In contrast to more comprehensive (and storage-intensive) checkpointing schemes, backtracking in this approach is constrained to limit storage requirements. The resulting debugger offers a structured view of dynamic events, similar to lexical scope rules' effect on static visibility. The debugger also speeds backtracking to statements before loops and provides what-if capabilities. >