Reduction strategies

An approach to copolymerization has been advanced by Price and Alfrey which attempts to both combine resonance and polarity considerations and accomplish the data reduction strategy of the last paragraph. It should be conceded at the outset that the Price-Alfrey method is only semiquantitative in its success. Its greatest usefulness is probably in providing some orientation to a new system before launching an experimental investigation. 

The process by which the results of a risk analysis (i.e., risk estimates) are used to make decisions, either through relative ranking of risk-reduction strategies or through comparison with risk targets... 

Depending on the results of the classification select an appropriate error reduction strategy in areas such as training, procedures or equipment design, as illustrated in Table 2.3. 

TYPICAL ERRORS ASSOCIATED WITH DIFFERENT INFORMATION PROCESSING LEVELS EXAMPLES OF ERROR REDUCTION STRATEGIES ... 

For errors with serious consequences and/or high likelihood of occurrence, develop appropriate error reduction strategies. 

This chapter has reviewed various PIFs which deterirune the likelihood of human error in the CPI. The list of PIFs in Table 3.1 can be used by engineers and managers to evaluate and audit existing work systems, analyze process incidents and generate error reduction strategies in conjunction with the techniques described in Chapters 4 and 5. 

Error analysis techniques can be used in accident analysis to identify the events and contributory factors that led to an accident, to represent this information in a clear and simple manner and to suggest suitable error reduction strategies. This is achieved in practice by identification of the causal event sequence that led to the accident and the analysis of this sequence to identify the root causes of the system malfunction. A discussion of accident analysis techniques is included in Chapter 6. 

TASK STEP TASK TYPE ERROR TYPE DESCRIPTION CONSEQUENCES RECOVERY ERROR REDUCTION STRATEGY... 

For those errors with significant consequences where recovery is unlikely, the qualitative analysis concludes with a consideration of error reduction strategies that will reduce the likelihood of these errors to an acceptable level. These strategies can be inferred directly from the results of the PIF analysis, since this indicates the deficiencies in the situation which need to be remedied to reduce the error potential. 

Figure 5.9 illustrates some of the possible error reduction strategies available. Apart from the specific strategies set out in Figure 5.9, the PIF analysis also indicates which PIFs should be modified to reduce the likelihood of error. In the case of the chlorine loading example, the major scope for improvements are the reduction of time stress and distractions and the development of better quality procedures. 

The qualitative human error analysis stages described above are applied to the task steps in subtask 3.2. Examples of the results of this analysis are shown in Figure 5.8. The corresponding error-reduction strategies are shown in Figure 5.9. 

ERROR REDUCTION STRATEGIES. If the error probability calculated by the above procedures leads to an unacceptable overall system failure probability, then the analyst will reexamine the event trees to determine if any PIFs can be modified or task structures changed to reduce the error probabilities to an acceptable level. 

The systems which are the major focus of this chapter are described below. They emphasize the identification of underlying causes and the use of this information to specify error and accident reduction strategies. 

The first area focuses on the cultural and organizational factors that will have a major influence on the effectiveness of a human error data collection system and how well the information derived from such a system is translated into successful error reduction strategies. Regardless of how effectively the technical issues are dealt with, the system will not be successful imless there is a culture in the organization which provides support for the data gathering process. No data collection system aimed at identifying human error causes of accidents will be workable without the active cooperation of the workforce. 

Emphasis on the Modification of System Factors as a Major Error Reduction Strategy This emphasis replaces the reliance on rewards and pLmishment as a means of error control which characterizes the TSE approach. 

This process will specify the methods for deriving error reduction strategies from the data collected, and the responsibilities for implementing these measures and monitoring their effectiveness. 

This case study illustrates how the methodologies described in Chapter 6 can be used to analyze plant incidents and identify the root causes of the problems. Based on this information, specific error reduction strategies can be developed to prevent similar incidents from occurring in the future. Also, the findings of such an analysis can provide the basis for more general discussions about the prevalence of similar error inducing conditions in other plant areas. 

Historically, risk reduction strategies have been focused on the exposure side of the risk equation and in many cases have been very successful. However, there are inherent flaws in focusing primarily on controlling exposure that will be identified here. 

Chianese, D. S., Rotz, C. A., and Richard, T. L. (2009b). Simulation of carbon dioxide emissions from dairy farms to assess greenhouse gas reduction strategies. Trans. ASABE 52,1301-1312. 

In a comparative study of disulfide reducing agents, it was determined that use of the relatively strong reductants DTT and TCEP required only 3.25 and 2.75 mole equivalents per mole equivalent of antibody molecule to achieve the reduction of two interchain disulfide bonds between the heavy chains of a monoclonal IgG (Sun et al., 2005). This limited reduction strategy retains intact bispecific antibody molecules while providing discrete sites for conjugation to thiols. 

Chlebowski RT, Collyar DE, Somerfield MR et al. (1999) American Society of Clinical Oncology technology assessment on breast cancer risk reduction strategies tamoxifen and raloxifene. J Clin Oncol 17 1939-1955... 

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