scholarly journals Analysis of the deployment strategies of reinforcement learning controllers for complex dynamic systems

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Ibrahim Ahmed ◽  
Marcos Quinones Grueiro ◽  
Gautam Biswas

This paper benchmarks several strategies for deploying reinforcement learning (RL)-based controllers on heterogeneous hybrid systems. Sample inefficiency is often a significant cost for RL controllers because we need sufficient data to train them, and the controllers may take time to converge to an acceptable control policy. This can be doubly costly if system health is degrading, or if the network of such systems in turn cannot afford a gradually improving controller in its constituents. Learning speed improvement can be achieved via transfer learning across controllers trained on different tasks: simulations, data-driven models, or separate instances of similar systems. This paper discusses near- and far- transfers across tasks of varying similarities. These approaches are applied on a test-bed of models of cooling towers operating on office and residential buildings on a university campus.

2021 ◽  
Vol 7 (s2) ◽  
Author(s):  
Marjolijn Verspoor ◽  
Wander Lowie ◽  
Kees de Bot

Abstract In recent studies in second language (L2) development, notably within the focus of Complex Dynamic Systems Theory (CDST), non-systematic variation has been extensively studied as intra-individual variation, which we will refer to as variability. This paper argues that variability is functional and is needed for development. With examples of four longitudinal case studies we hope to show that variability over time provides valuable information about the process of development. Phases of increased variability in linguistic constructions are often a sign that the learner is trying out different constructions, and as such variability can be evidence for change, and change can be learning. Also, a limited degree of variability is inherent in automatic or controlled processes. Conversely, the absence of variability is likely to show that no learning is going on or the system is frozen.


Author(s):  
Phil Hiver ◽  
Ali H. Al-Hoorie ◽  
Diane Larsen-Freeman

Abstract Complexity theory/dynamic systems theory has challenged conventional approaches to applied linguistics research by encouraging researchers to adopt a pragmatic transdisciplinary approach that is less paradigmatic and more problem-oriented in nature. Its proponents have argued that the starting point in research design should not be the quantitative–qualitative distinction, or even mixed methods, but the distinction between individual versus group-based designs (i.e., idiographic versus nomothetic). Taking insights from transdisciplinary complexity research in other human and social sciences, we propose an integrative transdisciplinary framework that unites these different perspectives (quantitative–qualitative, individual–group based) from the starting point of exploratory–falsificatory aims. We discuss the implications of this transdisciplinary approach to applied linguistics research and illustrate how such an integrated approach might be implemented in the field.


Author(s):  
Jerome E. Manning

Abstract Statistical energy analysis provides a technique to predict acoustic and vibration levels in complex dynamic systems. The technique is most useful for broad-band excitation at high frequencies where many modes contribute to the response in any given frequency band. At mid and low frequencies, the number of modes contributing to the response may be quite small. In this case SEA predictions show large variability from measured data and may not be useful for vibroacoustic design. This paper focuses on the use of measured data to improve the accuracy of the predictions. Past work to measure the SEA coupling and damping loss factors has not been successful for a broad range of systems that do not have light coupling. This paper introduces a new hybrid SEA technique that combines measured mobility functions with analytical SEA predictions. The accuracy of the hybrid technique is shown to be greatly improved at mid and low frequencies.


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