scholarly journals Thermofluid Modelling of Large-Scale Orchards for Optimal Design and Control of Active Frost Prevention Systems

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 378
Author(s):  
Ercan Atam ◽  
Se-Woon Hong ◽  
Alessia Arteconi
Keyword(s):  
Optimal Design ◽  
Control Systems ◽  
Large Scale ◽  
Initial Conditions ◽  
Minimum Energy ◽  
Prunus Armeniaca ◽  
Thermal Dynamics ◽  
Heating Systems ◽  
And Control

Accurate modelling and simulation of temperature dynamics in large-scale orchards is important in many aspects, including: (i) for the calculation of minimum energy required to be used in optimal design of active frost prevention energy systems (fully renewable or partially renewable) to prevent freezing of fruit flowers, buds, or leaves; (ii) for testing frost prevention control systems before real-implementation which regulate active heating systems inside orchards targeted to prevent frost. To that end, in this study, first, a novel and sophisticated parametric computational thermofluid dynamics (CTFD) model for orchard air thermal dynamics for different orchard parameters (such as fruit type, climate, number of trees, their sizes, and distance between them) and boundary/initial conditions was developed and validated with field data from the literature. Next, the use of the developed parametric CTFD model was demonstrated through a case study to calculate the minimal thermal energy required to prevent frost under different frost levels in a test Prunus armeniaca orchard located in Malatya, Turkey, which is the world capital for dry apricot production.

scholarly journals Manifold Calculus in System Theory and Control—Fundamentals and First-Order Systems

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2092
Author(s):  
Simone Fiori
Keyword(s):  
Control Systems ◽  
Linear Systems ◽  
Linear Control Systems ◽  
First Order ◽  
Curved Manifolds ◽  
Non Linear ◽  
Covariant Derivation ◽  
Non Linear Systems ◽  
And Control

The aim of the present tutorial paper is to recall notions from manifold calculus and to illustrate how these tools prove useful in describing system-theoretic properties. Special emphasis is put on embedded manifold calculus (which is coordinate-free and relies on the embedding of a manifold into a larger ambient space). In addition, we also consider the control of non-linear systems whose states belong to curved manifolds. As a case study, synchronization of non-linear systems by feedback control on smooth manifolds (including Lie groups) is surveyed. Special emphasis is also put on numerical methods to simulate non-linear control systems on curved manifolds. The present tutorial is meant to cover a portion of the mentioned topics, such as first-order systems, but it does not cover topics such as covariant derivation and second-order dynamical systems, which will be covered in a subsequent tutorial paper.

Reliability analysis and safety model checking of Safety-Critical and control Systems: A case study of NPP control system

2022 ◽  
Vol 166 ◽  
pp. 108812
Author(s):  
Vinay Kumar ◽  
Kailash Chandra Mishra ◽  
Pooja Singh ◽  
Aditya Narayan Hati ◽  
Mohan Rao Mamdikar ◽  
...  
Keyword(s):  
Control System ◽  
Model Checking ◽  
Reliability Analysis ◽  
Control Systems ◽  
Safety Critical ◽  
And Control

scholarly journals People in suits: a case study of empowerment and control in a non-profit UK organisation

2020 ◽  
Vol 32 (3) ◽  
pp. 511-528
Author(s):  
Roxana Corduneanu ◽  
Laura Lebec
Keyword(s):  
Control Systems ◽  
Management Control ◽  
Interactive Systems ◽  
Employee Perceptions ◽  
Structured Interviews ◽  
Content Type ◽  
Non Profit ◽  
And Control

PurposeDrawing on Simons's levers of control (LoC) framework, the primary aim of this study is to advance an understanding of the balance between empowerment and constraint in a non-profit UK organisation. In particular, this study examines the antecedents and manifestations of LoC (im)balance, in relation to employees' level of engagement with the control systems in place.Design/methodology/approachFor this study, 27 semi-structured interviews were conducted with different organisational members, from directors to non-managerial staff, to gain an in-depth appreciation of the main differences between managerial intentions in the design of management control systems (MCS) and employee perceptions regarding the role of such systems.FindingsThis research reveals that suppression of interactive systems and internal inconsistencies between different types of controls hinder the balance between empowerment and constraint. This imbalance is then found to have important consequences for employee buy-in, in some cases, defeating the purposes of control.Research limitations/implicationsThis study enhances our understanding of the gap between the design of control systems and the employee perceptions of it in an unusual organisational setting (non-profit and bringing together clinical and non-clinical staff and operations).Originality/valueThe study of MCS and its role in organisations has long been the focus of both academic and practitioner research. Yet, while extant literature focused on management's perspective on MCS, few studies have explored employees' attitudes and behaviours that accompany the implementation of control. What is more, little is known about the specific uses and behavioural outcomes of MCS in the context of non-profit organisations. Drawing on Simons's LoC framework, this paper addresses these gaps in the literature and investigates the balance between control and empowerment of employees in a UK non-profit organisation with significant clinical remit.

A New Method for Simultaneous Optimization of a Structure With Active and Passive Control Variables

2015 ◽  
Author(s):  
Ui-Jin Jung ◽  
Gyung-Jin Park
Keyword(s):  
Control Systems ◽  
Large Scale ◽  
Optimization Problem ◽  
Integrated System ◽  
Static Loads ◽  
Design Variables ◽  
Response Optimization ◽  
The Time Domain ◽  
Control Forces ◽  
And Control

An optimization method is proposed for the simultaneous design of structural and control systems using the equivalent static loads. The two structural and control systems are not completely independent and need to be considered in a unified fashion. Furthermore, an integrated system design is unavoidable to exhibit a good performance in the time domain. The analysis for the integrated system is conducted for the transient-state in a dynamic manner. The constraints for the structural and control systems are defined in the time domain as well. Therefore, a physically small scale problem in structural analysis easily becomes quite a large scale in an optimization problem. A new equivalent static loads (ESLs) method, which deals with the structural design variables as well as the control design variables, is proposed to solve physically large scale problems. A finite element dynamic equation is defined with control forces and a dynamic response optimization problem is formulated. Linear static response optimization is carried out with the ESLs. The control forces for the linear static response optimization are considered as design variables. Shape variables are utilized to handle the design variables for the control forces. Several examples are solved to validate the proposed method.

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