User-Adaptable Comfort Control for HVAC Systems

1994 ◽  
Vol 116 (3) ◽  
pp. 474-486 ◽  
Author(s):  
Clifford C. Federspiel ◽  
Haruhiko Asada
Keyword(s):  
Thermal Sensation ◽  
Human Subjects ◽  
A Priori ◽  
Hvac Systems ◽  
Lumped Parameter Model ◽  
New Approach ◽  
Tuning Parameters ◽  
Lumped Parameter ◽  
Priori Information ◽  
The Stability

This paper describes a new approach to the control of heating, ventilating, and air-conditioning (HVAC) systems. The fundamental concept of the new approach is that the controller learns to predict the actual thermal sensation of the specific occupant by tuning parameters of a model of the occupant’s thermal sensation. The parameters are adjusted with respect to thermal sensation ratings acquired from the specific occupant and measurements of physical variables that affect thermal sensation so that with time the model accurately reflects the thermal sensation of the specific occupant. From a lumped-parameter model of a singleroom enclosure, it is shown that the stability of the nominal system can be maintained by utilizing a priori information about the parameters of the thermal sensation model. The method is implemented on a ductless, split-system heat pump. Experiments using human subjects verify the feasibility of the method.

Investigation of New Generation of Ceramic and Single Crystalline Piezo Materials for Helicopter Blade and UAV Actuation

2013 ◽  
Author(s):  
Devdas Shetty ◽  
Claudio Campana ◽  
Nikolay Nazaryan ◽  
Louis Manzione
Keyword(s):  
Large Scale ◽  
Lumped Parameter Model ◽  
New Approach ◽  
Helicopter Blade ◽  
Aerospace Applications ◽  
Actuation System ◽  
Lumped Parameter ◽  
Piezoelectric Stacks ◽  
New Generation ◽  
Piezoelectric Stack Actuator

A great amount of research is being conducted to incorporate smart material actuators in aerospace applications such as (1) turbo fan engines (2) servo flap actuators for helicopter rotor control. For example, a piezoelectric stack actuator, coupled with mechanical or hydraulic amplification could provide the actuation required for the variable pitch fan system with a potentially higher level of reliability. In addition, piezoelectric actuation system could do so at a lower overall weight. However, there are limitations with existing piezoelectric stack actuators relative to power requirements. Therefore, a new approach has been investigated to improve these characteristics in order for piezoelectric stacks to be a feasible solution for these types of large scale applications. A new configuration involving dielectric, conductor, piezoelectric material in a particular sequence of stack actuation is examined and experimented. A nonlinear lumped parameter model of a piezoelectric stack has been developed to describe the behavior for the purpose of control actuation analysis.

Structural Decomposition Approach for the Stability of Uncertain Dynamic Systems

1988 ◽  
Vol 55 (4) ◽  
pp. 992-994 ◽  
Author(s):  
Y. H. Chen ◽  
Chieh Hsu
Keyword(s):  
Dynamic Systems ◽  
A Priori ◽  
Parameter Variation ◽  
Stability Study ◽  
Fast Time ◽  
Time Varying ◽  
Decomposition Approach ◽  
New Approach ◽  
Uncertain Dynamic Systems ◽  
The Stability

The stability property for a class of dynamic systems with uncertain parameter variation is studied. The uncertainty can be fast time-varying and unpredictable. A new approach for stability study is proposed. The only required information on the uncertain variation is its possible bound as well as structure. That is, no a priori knowledge on the realization of the variation is needed.

Inversion of inductive electromagnetic data in highly conductive terrains

Geophysics ◽  
2005 ◽  
Vol 70 (1) ◽  
pp. G16-G28 ◽  
Author(s):  
G. Schultz ◽  
C. Ruppel
Keyword(s):  
A Priori ◽  
Two Dimensions ◽  
Forward Model ◽  
Practical Applications ◽  
Shallow Subsurface ◽  
Subsurface Structures ◽  
Conductivity Structure ◽  
Actual Field ◽  
Priori Information ◽  
The Stability

Despite the increasing use of controlled-source frequency-domain EM data to characterize shallow subsurface structures, relatively few inversion algorithms have been widely applied to data from real-world settings, particularly in high-conductivity terrains. In this study, we develop robust and convergent regularized, least-squares inversion algorithms based on both linear and nonlinear formulations of mutual dipole induction for the forward problem. A modified version of the discrepancy principle based on a priori information is implemented to select optimal smoothing parameters that simultaneously guarantee the stability and best-fit criteria. To investigate the problems of resolution and equivalence, we consider typical layered-earth models in one and two dimensions using both synthetic and observed data. Synthetic examples show that inversions based on the nonlinear forward model more accurately resolve subsurface structure, and that inversions based on the linear forward model tend to drastically underpredict high conductivities at depth. Inversions of actual field data from well-characterized sites (e.g., National Geotechnical Experimentation Site; sand-dominated coastal aquifer in the Georgia Bight) are used to test the applicability of the model to terrains with different characteristic conductivity structure. A comparison of our inversion results with existing cone-penetrometer and downhole-conductivity data from these field sites demonstrates the ability of the inversions to constrain conductivity variations in practical applications.

scholarly journals Characterization of Giant Magnetostrictive Materials Using Three Complex Material Parameters by Particle Swarm Optimization

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1416
Author(s):  
Yukai Chen ◽  
Xin Yang ◽  
Mingzhi Yang ◽  
Yanfei Wei ◽  
Haobin Zheng
Keyword(s):  
Classical Method ◽  
Lumped Parameter Model ◽  
Complex Material ◽  
Material Parameters ◽  
Magnetostrictive Materials ◽  
Lumped Parameter ◽  
Giant Magnetostrictive Materials ◽  
Power Transducer ◽  
And Performance ◽  
The Stability

Complex material parameters that can represent the losses of giant magnetostrictive materials (GMMs) are the key parameters for high-power transducer design and performance analysis. Since the GMMs work under pre-stress conditions and their performance is highly sensitive to pre-stress, the complex parameters of a GMM are preferably characterized in a specific pre-stress condition. In this study, an optimized characterization method for GMMs is proposed using three complex material parameters. Firstly, a lumped parameter model is improved for a longitudinal transducer by incorporating three material losses. Then, the structural damping and contact damping are experimentally measured and applied to confine the parametric variance ranges. Using the improved lumped parameter model, the real parts of the three key material parameters are characterized by fitting the experimental impedance data while the imaginary parts are separately extracted by the phase data. The global sensitivity analysis that accounts for the interaction effects of the multiple parameter variances shows that the proposed method outperforms the classical method as the sensitivities of all the six key parameters to both impedance and phase fitness functions are all high, which implies that the extracted material complex parameters are credible. In addition, the stability and credibility of the proposed parameter characterization is further corroborated by the results of ten random characterizations.

The ILRS Contribution to ITRF2020

2021 ◽  
Author(s):  
Vincenza Luceri ◽  
Erricos C. Pavlis ◽  
Antonio Basoni ◽  
David Sarrocco ◽  
Magdalena Kuzmicz-Cieslak ◽  
...  
Keyword(s):  
Time Series ◽  
Tracking System ◽  
A Priori ◽  
Systematic Errors ◽  
Novel Approach ◽  
Priori Information ◽  
The Stability ◽  
The Individual ◽  
Stability And Consistency

<p>The International Laser Ranging Service (ILRS) contribution to ITRF2020 has been prepared after the re-analysis of the data from 1993 to 2020, based on an improved modeling of the data and a novel approach that ensures the results are free of systematic errors in the underlying data. This reanalysis incorporates an improved “target signature” model (CoM) that allows better separation of true systematic error of each tracking system from the errors in the model describing the target’s signature. The new approach was developed after the completion of ITRF2014, the ILRS Analysis Standing Committee (ASC) devoting almost entirely its efforts on this task. The robust estimation of persistent systematic errors at the millimeter level permitted the adoption of a consistent set of long-term mean corrections for data collected in past years, which are now applied a priori (information provided by the stations from their own engineering investigations are still taken into consideration). The reanalysis used these corrections, leading to improved results for the TRF attributes, reflected in the resulting new time series of the TRF origin and especially in the scale. Seven official ILRS Analysis Centers computed time series of weekly solutions, according to the guidelines defined by the ILRS ASC. These series were combined by the ILRS Combination Center to obtain the official ILRS product contribution to ITRF2020.</p><p>The presentation will provide an overview of the analysis procedures and models, and it will demonstrate the level of improvement with respect to the previous ILRS product series; the stability and consistency of the solution are discussed for the individual AC contributions and the combined SLR time series.</p>

Dynamic Response of a Cam-Actuated Mechanism With Pneumatic Coupling

1977 ◽  
Vol 99 (3) ◽  
pp. 598-603 ◽  
Author(s):  
F. Y. Chen
Keyword(s):  
Dynamic Response ◽  
Dynamic Characteristics ◽  
Lumped Parameter Model ◽  
System Equation ◽  
Variation Of Parameters ◽  
Lumped Parameter ◽  
Cam Follower ◽  
The Stability

The dynamic characteristics of a cam-actuated system whose follower mass is coupled with a nonlinear pneumatic mechanism of hysteretic type are investigated using a lumped-parameter model. The dynamic response of the cam follower is obtained from the solution of the formulated system equation by the Krylov-Bogoliubov method of variation of parameters. The stability of the system is also investigated.

Mode-Coupled Regenerative Machine Tool Vibrations

2003 ◽  
Author(s):  
Tama´s Kalma´r-Nagy ◽  
Francis C. Moon
Keyword(s):  
Machine Tool ◽  
Cutting Tool ◽  
Chip Thickness ◽  
The Other ◽  
Lumped Parameter Model ◽  
Regenerative Effect ◽  
Lumped Parameter ◽  
Tool Vibrations ◽  
The Stability ◽  
Effect Time

In this paper a new 3 degree-of-freedom lumped-parameter model for machine tool vibrations is developed and analyzed. One mode is shown to be stable and decoupled from the other two, and thus the stability of the system can be determined by analyzing the remaining two modes. It is shown that this mode-coupled nonconservative cutting tool model including the regenerative effect (time delay) can produce an instability criteria that admits low-level or zero chip thickness chatter.

Fluorescence Anisotropy Selective Technique (FAST): A New Approach to Multicomponent Fluorimetric Analysis

1988 ◽  
Vol 42 (7) ◽  
pp. 1245-1250 ◽  
Author(s):  
Frank V. Bright
Keyword(s):  
Fluorescence Anisotropy ◽  
Rotational Diffusion ◽  
A Priori ◽  
Emission Spectra ◽  
Fluorescence Lifetimes ◽  
New Approach ◽  
Fluorimetric Analysis ◽  
Priori Information ◽  
The Individual ◽  
Selective Technique

A new analytical approach to multicomponent fluorimetric analysis is presented theoretically and is experimentally demonstrated. The new approach, termed fluorescence anisotropy selective technique (FAST), allows one to directly resolve the individual components in complex mixtures on the basis of differences in the rotational diffusion rates of the components. Importantly, unlike steady-state polarization-based approaches, FAST does not require a priori information regarding the number of individual components. By the use of FAST, the individual emission spectra of the same fluorophore in two different microenvironments can be simultaneously determined even if the fluorescence lifetimes and emission spectra of the two components are extremely similar. To demonstrate the power of FAST, we show results for the simultaneous resolution of dansylamide bound to beta-cyclodextrin and human serum albumin. In this example, the fluorescence lifetimes of the two components are essentially identical.

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