Process Decisions

When we draw a scatter plot of all X versus Y data, we see that some sort of shape can be described by the data points. From the scatter plot we can take a basic guess as to which type of curve will best describe the X—Y relationship. To aid in the decision process, it is helpful to obtain scatter plots of transformed variables. For example, if a scatter plot of log Y versus X shows a linear relationship, the equation has the form of number 6 above, while if log Y versus log X shows a linear relationship, the equation has the form of number 7. To facilitate this we frequently employ special graph paper for which one or both scales are calibrated logarithmically. These are referred to as semilog or log-log graph paper, respectively. 

Decision Process. In many cases, the decision regarding the need for exposure reduction measures is obvious and no formal statistical procedure is necessary. However, as exposure criteria are lowered, and control becomes more difficult, close calls become more common, and a logical decision-making process is needed. A typical process is shown in Eigure 2. Even when decision making is easy it is useful to remember the process and the assumptions involved. Based on an evaluation, decisions are made regarding control. The evaluation and decision steps caimot be separated because the conduct of the evaluation, the strategy, measurement method, and data collection are all a part of the decision process. 

The hazard identification step is perhaps the most important, because any hazard not identified will not be considered in the decision process. For example, the impact of chlorofluorocarbons on atmospheric ozone was unknown for much of the period of their use, and this potential hazard was not considered until recent years. 

In many cases, formal tools for decision making can be useful, particularly if the hazards vary greatly in type of consequence or impact. Many of these tools introduce additional rigor, consistency, and logic into the decision process. Some available methods include ... 

Every analytical result forms the basis for a subsequent decision process. So the result should be subject to a high degree of precision and accuracy. This is also true of chromatographic methods. The physical detection methods described until now are frequently not sufficient on their own. If this is the case they have to be complemented by specific chemical reactions (derivatization). 

Rossiter and Douglas (1986) state that the first step in process design is to generate a basic structure for the flowsheet i.e. the choice of unit operations and interconnections which can be analysed, refined and costed, and then compared to alternatives. Thus, the generation of an industrial crystallization flowsheet gives rise to a number of optimization problems for which a systematic hierarchical decision process for particulate systems was proposed ... 

The following illustration of a decision process recently given by Gale and Shapley does not utilize the foregoing ideas on decision theory, but is both amusing and interesting in itself.47... 

This ability to provide a continuous perspective of key indicators, essentially as they are generated, enables multiple decision processes to proceed in parallel rather than waiting until the end of the study. The approach also has a number of other benehts that may not be immediately apparent but can significantly affect both cost and timelines for development. 

A. Solution Space Representation—Discrete Decision Process.555... 

The combinatorial problem is represented by a discrete decision process (DDP) (Ibaraki, 1978) where the underlying information in the problem is captured by an explicit state-space model (Nilsson, 1980). 

The first step in solving a combinatorial optimization problem is to model the solution space itself. Such a model should be declarative in character, if it is to be independent of the characteristics of the specific algorithm that will be used to find the solution within the solution space. The model we have adopted for the scheduling of flowshop operations is the discrete decision process (DDP) introduced originally by Karp and Held (1967). As defined by Ibaraki (1978) a DDP, Y, is a triple (.S,S,/) with its elements defined as follows ... 

If g(x) satisfies these conditions, we can use the following lower-bound elimination criterion to terminate the solution of a discrete decision process, T(y). 

Definition. A dominance relation, D, is a partial ordering of the partial solutions of the discrete decision processes in X, which satisfies the following three properties for any partial solutions, x and y. 

BEST PRACTICABLE ENVIRONMENTAL OPTION (bpeo) Orgauizatious may be eucouraged to uudertake systematic decision processes with a view to seeking the BPEO that provides the most benefit (or least damage) to the environment, at an acceptable cost. 

Progressing toward the goal of designing safer chemicals requires that the relative safety of chemicals can be compared so that a clear decision process can be identified. The metrics to accomplish this evaluation of the relative hazards of chemicals are well estabhshed but have not been applied to the field of green chemistry, specifically, designing safer chemicals. 

It is a decision process, often rigorous, which involves ... 

The final aim is to construct a formalized representation of the decision process. Decision trees and structured system analysis are possibilities. Some types of expert systems can derive their own rules from examples. These are described in Chapters 18 and 33. 

Reported data should achieve a clear, purpose-oriented level of accuracy and precision, especially when data produced by several laboratories often needs to be compared as part of a decision process. It has become accepted by more and more analysts that to overcome differences between national standards and specifications and measurement procedures or to make Total Quality Management (TQM) an achievable reality, freely available and internationally agreed points of reference are needed. Therefore RMs and CRMs must be easily available indeed the availability of reference materials has been described as an issue of strategic importance to the EU (Maier et al. 1997). 

Chen, L. W., and Modarres, M., Hierarchical decision process for fault administration, Comput. Chem. Eng. 16(5), 425-448 (1992). 

Although neither research decisions nor clinical practice decisions are made entirely on the basis of the published literature, the published literature is an extremely important component in the decision process. As such, how much stock can be placed in what the published literature says or concludes To answer this... 

Figure 16.5 shows a decision process for treatability studies.12... 

Zadeh LA (1975) Fuzzy sets and their applications to cognitive and decision processes. Academic Press, New York... 

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