Characterization of Damping and Beating Effects Within the Aggregate Power Demand of Heterogeneous Thermostatically Controlled Loads

2015 ◽  
Author(s):  
Donald J. Docimo ◽  
Hosam K. Fathy
Keyword(s):  
Population Heterogeneity ◽  
Parameter Distribution ◽  
Population Parameter ◽  
Control Input ◽  
Power Demand ◽  
Response Dynamics ◽  
Parameter Heterogeneity ◽  
Thermostatically Controlled Loads ◽  
Aggregate Dynamics

This paper presents an analysis of the damping and beating effects within the aggregate power demand of heterogeneous thermostatically controlled loads (TCLs). Demand response using TCLs is an appealing method to enable higher levels of penetration of intermittent renewable resources into the electric grid. Previous literature covers the benefits of TCL population heterogeneity for control purposes, but the focus is solely on the damping observed in these systems. This work is, to the best of the authors’ knowledge, the first to characterize the combined damping and beating response of power demand versus the level of TCL population parameter heterogeneity. The forced aggregate dynamics of TCLs have been shown to be bilinear when set point temperature adjustment is used as a control input. This motivates the paper’s use of free response dynamics, which are linear, to characterize both the damping and beating phenomena. A stochastic parameter distribution is applied to the homogeneous power demand solution, furnishing an analytic expression for aggregate power demand. The resulting analysis shows that increasing parameter heterogeneity increases damping and shortens the beat period.

Demand Response Using Heterogeneous Thermostatically Controlled Loads: Characterization of Aggregate Power Dynamics

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Donald Docimo ◽  
Hosam K. Fathy
Keyword(s):  
Demand Response ◽  
Population Heterogeneity ◽  
Power Dynamics ◽  
Parameter Distribution ◽  
Control Input ◽  
Power Demand ◽  
Response Dynamics ◽  
Parameter Heterogeneity ◽  
Thermostatically Controlled Loads ◽  
Aggregate Dynamics

This article presents an analysis of the damping and beating effects within the aggregate power demand of heterogeneous thermostatically controlled loads (TCLs). Demand response using TCLs is an appealing method to enable higher levels of penetration of intermittent renewable resources into the electric grid. Previous literature covers the benefits of TCL population heterogeneity for control purposes, but the focus is solely on the damping observed in these systems. This work, in contrast, characterizes the combined damping and beating effects in the power demand for different types of TCL parameter heterogeneity. The forced aggregate dynamics of TCLs have been shown to be bilinear when set point temperature adjustment is used as a control input. This motivates the article's use of free response dynamics, which are linear, to characterize both the damping and beating phenomena. A stochastic parameter distribution is applied to the homogeneous power demand solution, furnishing an analytic expression for the aggregate power demand. The time-varying damping ratios of this reduced-order model characterize the damping in the system. By analyzing a variety of case studies, it is determined that only a distribution of the TCL characteristic frequency creates damping in the aggregate power dynamics. The beating effect decays over time due to damping, and a relationship between the beat's amplitude and period is presented.

Design, Modeling, and Experimental Drag Characterization of a Bio-Inspired, Shape-Adapting Underwater Vehicle

2018 ◽  
Author(s):  
Levi D. DeVries ◽  
Michael D. M. Kutzer ◽  
Rebecca E. Richmond ◽  
Archie C. Bass
Keyword(s):  
Spatial Scales ◽  
Autonomous Underwater Vehicles ◽  
Major Axis ◽  
Underwater Vehicle ◽  
Great Promise ◽  
Hydrodynamic Drag ◽  
Control Input ◽  
Semi Major Axis ◽  
Generative Modeling

Autonomous underwater vehicles (AUVs) have shown great promise in fulfilling surveillance, scavenging, and monitoring tasks, but can be hindered in expansive, cluttered or obstacle ridden environments. Traditional gliders and streamlined AUVs are designed for long term operational efficiency in expansive environments, but are hindered in cluttered spaces due to their shape and control authority; agile AUVs can penetrate cluttered or sensitive environments but are limited in operational endurance at large spatial scales. This paper presents the prototype testbed design, modeling, and experimental hydrodynamic drag characterization of a novel self-propelled underwater vehicle capable of actuating its shape morphology. The vehicle prototype incorporates flexible, buckled fiberglass ribs to ensure a rigid shape that can be actuated by modulating the length of the semi-major axis. Tools from generative modeling are used to represent the vehicle shape by using a single control input actuating the vehicles length-to-diameter ratio. By actuating the length and width characteristics of the vehicle’s shape to produce a desired drag profile, we derive the feasible speeds achievable by shape actuation control. Tow-tank experiments with an experimental proto-type suggest shape actuation can be used to manipulate the drag by a factor between 2.15 and 5.8 depending on the vehicle’s operating speed.

scholarly journals Maximum Entropy Framework For Inference Of Cell Population Heterogeneity In Signaling Networks

2017 ◽  
Author(s):  
Purushottam D. Dixit ◽  
Eugenia Lyashenko ◽  
Mario Niepel ◽  
Dennis Vitkup
Keyword(s):  
Cell Population ◽  
Egf Receptor ◽  
Joint Probability ◽  
Network Models ◽  
Population Heterogeneity ◽  
Signaling Networks ◽  
Joint Probability Distribution ◽  
Parameter Distribution ◽  
Signaling Dynamics ◽  
Phosphorylated Akt

AbstractPredictive models of signaling networks are essential tools for understanding cell population heterogeneity and designing rational interventions in disease. However, using network models to predict signaling dynamics heterogeneity is often challenging due to the extensive variability of signaling parameters across cell populations. Here, we describe a Maximum Entropy-based fRamework for Inference of heterogeneity in Dynamics of sIgAling Networks (MERIDIAN). MERIDIAN allows us to estimate the joint probability distribution over signaling parameters that is consistent with experimentally observed cell-to-cell variability in abundances of network species. We apply the developed approach to investigate the heterogeneity in the signaling network activated by the epidermal growth factor (EGF) and leading to phosphorylation of protein kinase B (Akt). Using the inferred parameter distribution, we also predict heterogeneity of phosphorylated Akt levels and the distribution of EGF receptor abundance hours after EGF stimulation. We discuss how MERIDIAN can be generalized and applied to problems beyond modeling of heterogeneous signaling dynamics.

scholarly journals Two-level modeling approach to identify the regulatory dynamics capturing drug response heterogeneity in single-cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Madalena Chaves ◽  
Luis C. Gomes-Pereira ◽  
Jérémie Roux
Keyword(s):  
Drug Resistance ◽  
Single Cell ◽  
Cell Response ◽  
Drug Response ◽  
Single Cells ◽  
Reaction Model ◽  
Population Heterogeneity ◽  
Cellular Heterogeneity ◽  
Response Dynamics ◽  
Modeling Approach

AbstractSingle-cell multimodal technologies reveal the scales of cellular heterogeneity impairing cancer treatment, yet cell response dynamics remain largely underused to decipher the mechanisms of drug resistance they take part in. As the phenotypic heterogeneity of a clonal cell population informs on the capacity of each single-cell to recapitulate the whole range of observed behaviors, we developed a modeling approach utilizing single-cell response data to identify regulatory reactions driving population heterogeneity in drug response. Dynamic data of hundreds of HeLa cells treated with TNF-related apoptosis-inducing ligand (TRAIL) were used to characterize the fate-determining kinetic parameters of an apoptosis receptor reaction model. Selected reactions sets were augmented to incorporate a mechanism that leads to the separation of the opposing response phenotypes. Using a positive feedback loop motif to identify the reaction set, we show that caspase-8 is able to encapsulate high levels of heterogeneity by introducing a response delay and amplifying the initial differences arising from natural protein expression variability. Our approach enables the identification of fate-determining reactions that drive the population response heterogeneity, providing regulatory targets to curb the cell dynamics of drug resistance.

EXPLORING THE EFFECTS OF PARAMETER HETEROGENEITY ON THE INTRINSIC DYNAMICS OF HIV/AIDS IN HETEROSEXUAL SETTINGS

2011 ◽  
Vol 04 (01) ◽  
pp. 75-92
Author(s):  
E. T. NGARAKANA-GWASIRA ◽  
C. P. BHUNU ◽  
S. MUSHAYABASA ◽  
S. D. HOVE-MUSEKWA ◽  
W. GARIRA ◽  
...  
Keyword(s):  
Population Heterogeneity ◽  
Transmission Dynamics ◽  
Heterosexual Transmission ◽  
Related Parameter ◽  
Basic Model ◽  
Progression Model ◽  
Mathematical Properties ◽  
Parameter Heterogeneity ◽  
Epidemiological Parameters ◽  
Hiv Aids

A sex-structured staged progression model for heterosexual transmission dynamics of HIV/AIDS in a community to theoretically assess the effects of gender parameter accounting for population heterogeneity is formulated and analyzed. The basic model without this parameter is analyzed, and then extended to include gender heterogeneity in order to explore its role on the transmission dynamics of the disease. Mathematical properties including epidemic thresholds known as reproductive numbers are derived. The models are numerically analysed using some demographic and epidemiological parameters for Zimbabwe. These simulations suggest that the use of identical gender attributes simplifies computation at the expense of reality as it underestimates the size of the epidemic by 5%. This study demonstrates that the use of gender related parameter in the transmission dynamics of HIV gives a better estimate of the prevalence of the epidemic and should be given prominence.

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