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A. H. Glattfelder

Bio: A. H. Glattfelder is an academic researcher. The author has contributed to research in topics: Automation & Automatic control. The author has an hindex of 1, co-authored 1 publications receiving 5 citations.

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Journal ArticleDOI
TL;DR: Various optimization‐based workload distribution strategies and optimization techniques proposed in recent research works based on commonly used optimization factors such as workload type, load balancer, availability of renewable energy, energy storage, and data center server specification in geographically distributed data centers are summarized.

12 citations

DissertationDOI
01 Jan 1986
TL;DR: The intention is to find guidelines for a "design for controllability", which complement the existing steadystate design methods, in the new field of heat exchanger network dynamics.
Abstract: The heat exchanger network method is a way of abstracting the en¬ thalpy and heat flows from the blueprints of a planned or existing processing plant. It enables a systematic design of a plant-wide heat recovery system which is optimal with regard to energy costs, capital costs and operational requirements. A heat exchanger network is a representation of all heat transfer relations between hot process streams (i.e. those which have to be cooled down, e.g. products of distillation) and cold process streams (i.e. those which have to be heated up, e.g. feeds to distillation) within a plant. During the past ten years, the optimal design of heat exchanger networks (i.e. the optimal arrangement of heat transfer relations within a plant) has developed into a field of research of its own. Most of the research in this field has concentrated on the steady-state performance of heat exchanger networks on both fixed and variable operating conditions (in the latter case the term "resilience" is fre¬ quently used). In this work, networks are investigated with respect to their dynamic performance. The intention is to find guidelines for a "design for controllability", which complement the existing steadystate design methods. Both, static methods ("interaction analysis") and dynamic methods ("process reaction curve analysis") from control theory have been used to explore the new field of heat exchanger network dynamics. As a major tool, an interactive, portable computer program for network simulation and controllability assessment has been developed (it is available as a design tool within the frame of the International Energy Agency). Based on the well-understood global parameters: effectiveness and NTU, which follow from the network design, some straightforward methods covering the following topics are presented:

9 citations

Journal ArticleDOI
TL;DR: In this paper, a phase criterion is used to check whether nonlinear oscillations and nonlinear instability can be circumvented by an additional network around the saturating element, and the design of this additional network also uses the phase criterion.
Abstract: Plant input saturation may have a noxious influence on the closed loop transients and on closed loop stability. The widest known effect of this nonlinearity are considerable overshoots in the controlled variable, the so-called reset windup. This windup is caused by dynamic elements in the controller and it can be prevented systematically. After systematic windup prevention the reference behaviour is the same as if static state feedback had been applied. But even in the absence of dynamic controller elements, nonlinear overshoots or even nonlinear limit cycles are possible when the closed loop poles are shifted too far left. A phase criterion allows an easy check whether these problems have to be expected or not. If the phase criterion is violated, nonlinear oscillations and nonlinear instability can be circumvented by an additional network around the saturating element. The design of this additional network also uses the phase criterion

4 citations

Journal ArticleDOI
TL;DR: In this paper, Thoma verwies in seiner Rede noch einmal auf die enorme Weiterentwicklung, die die Regelungstechnik in den letten Jahren genommen hat.
Abstract: nun bis 1987 an der Spitze dieser Organisation stehen wird. Μ. Thoma verwies in seiner Rede noch einmal auf die enorme Weiterentwicklung, die die Regelungstechnik in den letzten Jahren genommen hat. Ihre Methoden spielen im zunehmenden Maße nicht nur im technischen Bereich, sondern auch auf Gebieten wie der Wirtschaft, Soziologie und Biologie eine wesentliche Rolle. Er nannte in diesem Zusammenhang zwei besonders wichtige Gründe, die beide eng verknüpft sind mit den ungeheuren Fortschritten der Mikroelektronik. Die leistungsfähigen und dennoch kostengünstigen Bauelemente, wie Mikrorechner, ermöglichen die effiziente Implementierung der modernen Verfahren der Regelungstheorie auch bei kleineren Systemen. Außerdem unterstützten leistungsfähige Digitalrechner die Modellbildung sowohl technischer als auch nichttechnischer Prozesse und erlauben damit einen tieferen Einblick in die inneren Zusammenhänge solcher Prozesse. Es ist ζ. B. im Zusammenhang mit den drängenden Umweltschutzproblemen zu erwarten, daß mit Hilfe der so gewonnenen größeren Kenntnis der Prozeßabläufe ein wesentlicher Beitrag zur Verbesserung unserer Lebensbedingungen geleistet werden kann. M. Thoma Schloß seine Ansprache mit einer Einladung zum 10. IFAC-Weltkongreß. der in der Zeit vom 27. bis 31. Juli 1987 in München stattfinden wird.