Information processing limited capacity

As was also noted, one cannot ideally isolate the systems under test. The required involvement of human sensory and motoric systems also requires the use of ancillary performance tests that establish at least some minimal levels of performance availabilities in these systems (e.g., visual acuity, etc.) in order to lend validity to measures of information-processing performance capacities. New imaging techniques and advanced electroencephalographic and magnetoencephalographic techniques such as brain mapping may offer the basis for new approaches that circumvent in part this limitation. While the cost and practicality of using these techniques routinely is likely to be prohibitive for the foreseeable future, the use of such techniques in research settings to optimize and establish validity of simpler methods can be anticipated. 

More exact solution available Phenomena follow from calculations a priori Formal balance equations can be written straightforwardly (for single phase systems) Processes can be visualized Simple models and simple solutions facilitate understanding Can be adapted to the detail of information required Limited calculation capacity often sufficient After adjustment of parameters accurate macroscale behavior prediction... 

Follovdng the collection of information and the data summarized in Tab. 9.1 and after completing the pre-selection process, which is a desk job, it normally becomes necessary to carry out laboratory tests, for example, to determine what type of binder must be added and how much of it is required. After that, trials with the actual equipment must be conducted to find process and capacity limitations and optimize product size, shape, and characteristics. Needs for peripheral equipment, post-treatment, closed-loop processing, and recirculation must be also evaluated. 

Although the interdependency of supply risks is well-known in chemical production networks, it is difficult to quantify the effects arising from certain sources of uncertainties. This is caused by the complexity of production processes, the interconnectedness of the production network, and the limited capacities of commonly used logistical infrastructures. However, quantitative information is necessary to determine economically reasonable risk management decisions. 

Many of the past efforts in which performance-related measurements have played a significant role have been directed toward basic research. Furthermore, much of this research has been aimed at uncovering the general operational frameworks of normal human information processing and not the measurement of performance capacities and their use, either alone or in combination with other capacity metrics, to characterize humans of various types (e.g., normal, aged, handicapped, etc.). However, representative models and theories provide direction for, and are themselves shaped by, subsequent measurement efforts. While there are many principles and basic observations that have some relevance, the scope of material presented later is limited to topics that more specifically support the understanding of human informationprocessing performance capacity measurement. 

In considering the performance of human information-processing systems, the resource-based perspective represented by the Elemental Resource Model (Kondraske, 2000) is adopted here. This model for human performance encompasses all types of human subsystems and is the result of the application of a general theoretical framework for system performance to the human system and its subsystems. A central idea incorporated in this framework, universal to all types of systems, is that of performance capacity. This implies a finite availability of some quantity that thereby limits performance. A general two-part approach is used to identify unique performance capacities (e.g., visual information processor speedy. (1) identify the system (e.g., visual information processor) and (2) identify the dimension of performance (e.g., speed). In this framework, system performance capacities are characterized by availability of performance resources along each of the identified dimensions. These performance resources... 

Speed-accuracy trade-off A fundamental limit of human information-processing systems at any level of abstraction that is most likely due to a more basic limit in channel capacity that is, channel capacity can be used to achieve more accuracy at the expense of speed or to achieve more speed at the expense of accuracy. 

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