Operant tasks

Applying the information-processing model to each of the operator tasks can provide insights into the potential for human error and also suggest solutions for preventing errors. 

Human Factors Engineering/Ergonomics approach (control of error by design, audit, and feedback of operational experience) Occupational/process safety Manual/control operations Routine operation Task analysis Job design Workplace design Interface design Physical environment evaluation Workload analysis Infrequent... 

The applicability of these findings for actual operational tasks was evaluated by considering the incidence of data entry errors recorded by the on-line plant computer system over the 24-hour shift cycles. It was judged that the data entry task, which involved evaluating the set point changes needed for... 

Case study 3 illustrates the use of proactive techniques to analyze operator tasks, predict errors and develop methods to prevent an error occurring. Methods for the development of operating instructions and checklists are shown using the same chemical plant as in case study 2. 

Solvent pumped to wrong blender— contaminated batch Reduce noise levels. Reschedule operator tasks to reduce overload. Incorporate use of procedures in training scheme. 

Task Analysis and Error Analysis of the Blowdown Operation Task analysis was carried out in order to organize all the performance data about the way that workers process information, the nature of the emergency and the way that decisions are made. Figure 7.20 shows a tabular task analysis of the workers response to a significant unignited gas leak in MSM. The analysis was a combination of a tabular HTA and a CADET analysis (see Chapter 4). Human error analysis identified the major human failure modes which could affect time to blowdown (see Table 7.2). 

Stratification of operational tasks, shown in Fig. 2 (Stephanopoulos, 1990). At the lowest level of abstraction, process data at a scale of seconds or minute are used to carry out a variety of numerical and logical tasks. 

Multiscale modeling of process operations. The description of process variables at different scales of abstraction implies that one could create models at several scales of time in such a way that these models communicate with each other and thus are inherently consistent with each other. The development of multiscale models is extremely important and constitutes the pivotal issue that must be resolved before the long-sought integration of operational tasks (e.g., planning, scheduling, control) can be placed on a firm foundation. 

Human Reliability Analysis (HRA) or Human Error Analysis - A reliability analysis that estimates the potential for human errors to occur due to the work environment, human-machine interfaces, and required operational tasks. 

Not all operators have the TotalOrdering properties. For example, when you make a project plan, the tasks have only a partial ordering with respect to the must-precede operator. Task A must be finished before B and C, and both B and C must be finished before D... 

Lockout/Tagout—A safe work practice in which energy sources are positively blocked away from a segment of a process with a locking mechanism and visibly tagged as such to help ensure worker safety during maintenance and some operations tasks. 

MARPFOT mapping application for response planning and operational tasks... 

Direct links exist as well to feedback between the different survey stages and the relevant stages of project development. Forecast information that is received at each survey stage represents the basis for the design, construction and operation tasks. 

Unit Operation/Task Step Potential Route of Exposure Duration Qualitative Exposure Assessment (Person Handling the Material) Precautions Required... 

The batch distillation operation can be schematically represented as a State Task Network (STN). A state (denoted by a circle) represents a specified material, and a task (rectangular box) represents the operational task (distillation) which transforms the input state(s) into the output state(s) (Kondili et al., 1988 Mujtaba and Macchietto, 1993). For example, Figure 3.1 shows a single distillation task producing a main-cut 1 (Di) and a bottom residue product (Bj) from an initial charge (B0). States are characterized by the amount and composition of the mixture residing in them. Tasks are characterized by operational attributes such as then-duration, the reflux ratio profile used during the task, etc. 

The recovery of component 1 in main-cut 1 (Re D1) was defined in Equation 6.2. The recoveries for each subsequent operation task can be defined as ... 

In general, if the amount and composition of the feed state are known then fixing two degrees of freedom (as mentioned above) for each distillation task (STN module) determines the thermodynamic distillation map which should be followed and results in a distillation profile which is well defined. The technique presented is general and can be easily extended to other networks involving larger number of operation tasks and components. 

The reflux ratio is discretised into two control intervals for each operation task. Three cases were considered with different sales values for the two main-cuts. For all cases, the optimal recovery of component 1 in task 1 and that of component 2 in task 2, the optimal amounts of main-cut 1, off-cut 1 and main-cut 2, the optimal... 

On the basis of our own informal observations and discussions in process control rooms, e.g. Van dcr Schaaf (1989), and the classical literature on operator tasks (Grossman, 1974) the following set of elementary operator requirements in order to carry out. process control tasks correctly, has been identified ... 

Corporate human resources should ensure conformity in standards across the businesses - for example, in employee evaluation processes, incentive plans, benefit plans, and training pohcies. As in other functions, aU operational tasks should be outsourced or operated as shared services at SBU level - for example, payroll, human resources information systems, a database on internal job opportunities, or the administration of benefit plans. The center should be active in developing top talent across the businesses, and it should run the goldfish pool for internal top talent and the company s program for recmiting experienced persoimel. This responsibility also includes the early identification of skills needed by the entire organization, for example, e-commerce skills to kick-start new businesses. The center must also act as a repository of expertise on internal and external best practices in talent management... 

A prime example of such an approach in the chemical industry is DuPont The American giant has established a powerful target-setting process that starts with so-called critical operating tasks (COTs). These are derived from financial origins at the business unit level, and cascade down through the plant to the production line. The system creates transparency for each production line employee about his or her targets and about how the individual s performance is linked to that of the whole unit (Fig. 12.4). 

There are several operant tasks that offer the opportunity to separate an animal s learning from its performance of a known task. Repeated acquisition is such a task and requires the animal to learn a new sequence of lever presses each session. The learning baseline may be more sensitive to disruption by a toxicant than the performance of an already acquired sequence. 

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