Control and coordination in hierarchical systems (original) (raw)
Coordination mechanisms in complex hierarchical systems
International Journal of Information and Decision Sciences, 2017
The objective of this article is to examine and comparatively analyse the models, methods and algorithms of coordination in the hierarchical systems, as well as to determine an optimal general approach to harmonise and accelerate the information flow between the different levels of the hierarchy. In these systems, changing the concept of optimality, so it is very difficult to find an adequate mathematical formulation of the problems and attach a reasonable meaning to the optimality notion. In particular, this paper formulated the coordination task, analysed and mathematically formalised by two groups the coordination algorithms in the multilevel hierarchical systems, including iterative and non-iterative algorithms. Both coordination methods have the role to transfer the information between the hierarchical sublevels and to accelerate the evaluation and implementation of an optimal solution for the control problem. The obtained results are intended to be used in contribution of decision support multilevel hierarchical systems under different conditions and with different systems complexity.
Proceedings. 5th IEEE International Symposium on Intelligent Control 1990, 1990
In this paper, we introduce the hierarchical coordination of independent systems modelled by automata in the Ramadge-Wonham (RW) framework. The setup features a high-level coordinator that regulates, in a common language, low-level operators to cooperate in achieving a common goal. Each low-level operator enforces a corresponding local control requirement , but must refer to the high-level for coordinating commands. It is shown that for delay-free systems, consistent feedback control is achieved, in the combined system of coordinator and local controllers.
Hierarchical Control and Driving
We manipulated primary task predictability and secondary task workload in the context of driving an automobile. As the driving task became less predictable (by adding wind gusts), more attention was required to maintain lane position. When drivers concurrently engaged in a secondary cognitive task in the windy driving condition, attention was diverted from driving and the ability to maintain lane position was degraded. By contrast, when the driving task was predictable (no wind), lane maintenance actually improved when a secondary cognitive task diverted attention from driving. These data provide evidence for a hierarchical control network that coordinates an interaction between automatic, encapsulated routines and limited capacity attention. In this article, we provide evidence that complex skilled behavior as diverse as playing a musical instrument, typing a manuscript, and driving an automobile are supported by a hierarchical control network that coordinates an interaction between automatic, encapsulated routines and limited capacity attention. Following Logan and Crump (2011), we assume that complex skills are goal directed. For example, musicians do not play instruments by accident , nor do drivers drive their cars by happenstance. Despite the fact that complex skills are goal directed, many times skilled performers do not know how they achieve high levels of performance , and thinking about it tends to impair performance on the task (Tapp & Logan, 2011). To help account for this puzzling characteristic of behavior, Fodor (1983) argued that separate control systems underlie skilled performance. One system is under attentional control and is easily brought into conscious awareness. The other system is automatic and operates outside of awareness. This division was initially described in terms of a hierarchy with higher and lower levels of control. For example, Shaffer (1976) found that musicians often used two levels of control for musical performance. One level would monitor a song and notes to be played and another level would control the execution of finger movements. When a person first learns how to play the piano, the higher control level would be required for processing the song and notes as well as monitoring the hands to depress the proper keys. In these instances, the higher level is engaged and acting directly to achieve the task of playing the instrument, and performers are keenly aware of their performance. With practice, the higher level of control is not needed to accomplish the task. Instead, some of the work can be offloaded to the lower level of control, which would then directly influence performance. Finally, with extensive practice, the lower control level can become encapsulated such that it does not require higher level involvement. When this happens, performance on the task is characterized as automatic and requires minimal attention or effort (Shiffrin & Schneider, 1977). However, if the task environment changes to become unpredictable, higher level attentional control would again be required for successful performance on the task. The notion of hierarchical control for skilled performance has advanced over the years and has been vetted using other tasks outside of musical performance. Recently, Logan and Crump (2009) used the metaphor of control loops rather than levels to describe complex typing and suggested that skilled typists rely on outer and inner loops of control for their complex performance. Specifically, the outer loop was responsible for selecting the words to be typed while the inner loop was responsible for controlling the execution of individual keystrokes. It is interesting that when participants were instructed to attend to the individual keystrokes, performance declined. The authors explained this by suggesting that the new task requirements caused the outer loop to monitor the output of the inner loop, and this additional monitoring disrupted encapsulated inner loop processing.
Information Fusion and Control in Hierarchical Systems
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A comparative experiment of control architectures
Computers in Industry, 1996
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The Role of Hierarchy in Self-Organizing Systems
Human Systems Management
This paper discusses the role of hierarchy in human systems. Two kinds of self-organizing processes are distinguished: conservative and dissipative self-organization. The former leads to rather stable, specialistic systems, whereas the latter leads to continuously changing generalistic systems. When conservative and dissipative self-organization are combined, autonomous self-organization emerges. Autonomous self-organization, characterized by intertemporal stability, appears to be fundamental to human organizations. In the context of autonomous self-organization, the traditional concept of hierarchy as a chain of command is replaced by hierarchy as a vertical sequence based on different degrees of abstraction. Moreover, a simple model shows that autonomous self-organization requires large human systems to use a variety of information processing systems, including administrative hierarchy. The model suggests hierarchy is one instrument for variety reduction amid several others.