scholarly journals How Long does a Generation Last? Assessing the Relationship Between Infinite and Finite Horizon Dynamic Models*

2021 ◽  
Author(s):  
Marco Guerrazzi
Keyword(s):  
Dynamic Models ◽  
Finite Horizon ◽  
The Relationship

scholarly journals Online Reviews and Product Sales: The Role of Review Visibility

2021 ◽  
Vol 16 (4) ◽  
pp. 638-669
Author(s):  
Miriam Alzate ◽  
Marta Arce-Urriza ◽  
Javier Cebollada
Keyword(s):  
Decision Making ◽  
Dynamic Models ◽  
Generalized Method Of Moments ◽  
Online Reviews ◽  
Consumer Decision Making ◽  
Product Sales ◽  
The Impact ◽  
The Relationship ◽  
The Empirical Analysis

When studying the impact of online reviews on product sales, previous scholars have usually assumed that every review for a product has the same probability of being viewed by consumers. However, decision-making and information processing theories underline that the accessibility of information plays a role in consumer decision-making. We incorporate the notion of review visibility to study the relationship between online reviews and product sales, which is proxied by sales rank information, studying three different cases: (1) when every online review is assumed to have the same probability of being viewed; (2) when we assume that consumers sort online reviews by the most helpful mechanism; and (3) when we assume that consumers sort online reviews by the most recent mechanism. Review non-textual and textual variables are analyzed. The empirical analysis is conducted using a panel of 119 cosmetic products over a period of nine weeks. Using the system generalized method of moments (system GMM) method for dynamic models of panel data, our findings reveal that review variables influence product sales, but the magnitude, and even the direction of the effect, vary amongst visibility cases. Overall, the characteristics of the most helpful reviews have a higher impact on sales.

scholarly journals On Designing an Expert Diagnostic System of the Aircraft Turbine Engine Functional Units

2020 ◽  
Vol 50 (1) ◽  
pp. 171-192
Author(s):  
Henryk Borowczyk ◽  
Jarosław Spychała
Keyword(s):  
Dynamic Models ◽  
Diagnostic System ◽  
Compact Representation ◽  
Diagnostic Model ◽  
Diagnostic Systems ◽  
Turbine Engine ◽  
Flight Data ◽  
Diagnostic Parameters ◽  
Functional Units ◽  
The Relationship

AbstractThe paper presents issues related to the design of an expert diagnostic system of turbine engine functional units. Dedicated diagnostic stations and on-board flight data recorders are the sources of diagnostic signals. The signals were parameterized or identified dynamic models to get a compact representation in the form of a set of parameters. The set of diagnostic parameters was subjected to integer encoding. On this basis, a multi-valued diagnostic model describing the relationship between the set of faults and the set of symptoms (code values of diagnostic parameters) was determined. The proposed approach can be used in the design of expert diagnostic systems for propulsion units of any aircraft.

Revisited the Relationship Between Economic Growth and Transport Infrastructure in India: An Empirical Study

2021 ◽  
pp. 001946622110635
Author(s):  
Prabir Kumar Ghosh ◽  
Soumyananda Dinda
Keyword(s):  
Economic Growth ◽  
Dynamic Models ◽  
Composite Index ◽  
Principal Component ◽  
Transport Infrastructure ◽  
Positive Contribution ◽  
Model Framework ◽  
Vector Error Correction ◽  
Long Run ◽  
The Relationship

This study empirically re-examines the relationship between transport infrastructure and economic growth in India for the period 1990–2017. Multivariate dynamic models are applied to estimate the relationship between economic growth and different modes of transport infrastructure namely road, rail and air transports in the vector error correction model framework. The results reveal that road and air transports have significant positive contribution to economic growth in the long-run while rail transport is insignificant. This study further examines the said issue using unit free index variables and has constructed a composite index of transport infrastructure using principal component analysis to analyse the nexus between aggregate transport infrastructure and economic growth in India in the post globalisation era. The results of the study indicate the bidirectional causality between aggregate transport infrastructure and economic growth. Results of this study suggest incorporating feedback issue in policy formulations. JEL Codes: C22, O18, R4

scholarly journals Impact of coherence decay on wavepacket models for broadband shock-associated noise in supersonic jets

2019 ◽  
Vol 863 ◽  
pp. 969-993 ◽  
Author(s):  
Marcus H. Wong ◽  
Peter Jordan ◽  
Damon R. Honnery ◽  
Daniel Edgington-Mitchell
Keyword(s):  
Dynamic Models ◽  
Critical Role ◽  
Coherence Function ◽  
Supersonic Jets ◽  
Far Field ◽  
Shock Cell ◽  
Acoustic Spectrum ◽  
Flow Mechanisms ◽  
The Relationship ◽  
Field Sound

Motivated by the success of wavepackets in modelling the noise from subsonic and perfectly expanded supersonic jets, we apply the wavepacket model to imperfectly expanded supersonic jets. Recent studies with subsonic jets have demonstrated the importance of capturing the ‘jitter’ of wavepackets in order to correctly predict the intensity of far-field sound. Wavepacket jitter may be statistically represented using a two-point coherence function; accurate prediction of noise requires identification of this coherence function. Following the analysis of Cavalieri & Agarwal (J. Fluid Mech., vol. 748, 2014. pp. 399–415), we extend their methodology to model the acoustic sources of broadband shock-associated noise in imperfectly expanded supersonic jets using cross-spectral densities of the turbulent and shock-cell quantities. The aim is to determine the relationship between wavepacket coherence-decay and far-field broadband shock-associated noise, using the model as a vehicle to explore the flow mechanisms at work. Unlike the subsonic case where inclusion of coherence decay amplifies the sound pressure level over the whole acoustic spectrum, we find that it does not play such a critical role in determining the peak sound amplitude for shock-cell noise. When higher-order shock-cell modes are used to reconstruct the acoustic spectrum at higher frequencies, however, the inclusion of a jittering wavepacket is necessary. These results suggest that the requirement for coherence decay identified in prior broadband shock-associated noise (BBSAN) models is in reality the statistical signature of jittering wavepackets. The results from this modelling approach suggest that nonlinear jittering effects of wavepackets need to be included in dynamic models for broadband shock-associated noise.

scholarly journals The Center for Human Modeling and Simulation

1995 ◽  
Vol 4 (1) ◽  
pp. 81-96 ◽  
Author(s):  
Norman I. Badler ◽  
Dimitri Metaxas ◽  
Bonnie Webber ◽  
Mark Steedman
Keyword(s):  
Modeling And Simulation ◽  
Dynamic Models ◽  
Human Movement ◽  
Image Synthesis ◽  
Human Modeling ◽  
Human Movement Modeling ◽  
Illumination Models ◽  
The Relationship ◽  
Rendering Techniques ◽  
Human Modeling And Simulation

The overall goals of the Center for Human Modeling and Simulation are the investigation of computer graphics modeling, animation, and rendering techniques. Major focii are in behavior-based animation of human movement, modeling through physics-based techniques, applications of control theory techniques to dynamic models, illumination models for image synthesis, and understanding the relationship between human movement, natural language, and communication.

scholarly journals Dynamic Models of the Creative Industries’ Behaviour

2020 ◽  
Vol 83 ◽  
pp. 01036
Author(s):  
Mária Kozáková ◽  
Kristína Krúpová
Keyword(s):  
Intellectual Property ◽  
Cultural Policy ◽  
Dynamic Models ◽  
Creative Industries ◽  
Statistical Tools ◽  
Policy Consideration ◽  
Cultural Statistics ◽  
Consistent Basis ◽  
The Relationship ◽  
Aggregate Economy

The aim of the paper is to analyse the models describing the development of the Creative Industries in Slovakia. Creative industries are described as the industrial components of the economy in which creativity is an input and content or intellectual property is the output. The creative industries have therefore appeared to be newly represented as a significant and rapidly growing set of industries; an important sector, in other words, for policy consideration. Based on the following findings, we can conclude that the second model is precisely predicting the relationship between the growth in the creative industries and in the aggregate economy in Slovakia. With improved cultural statistics, also a more developed and theoretically better founded analysis would be possible. We therefore see our article primarily as a much-needed step towards developing statistical tools in empirical cultural policy on a consistent basis.

scholarly journals The Kinematic and Dynamic Modeling and Numerical Calculation of Robots with Complex Mechanisms Based on Lie Group Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-34
Author(s):  
Lu-Han Ma ◽  
Yong-Bo Zhong ◽  
Gong-Dong Wang ◽  
Nan Li
Keyword(s):  
Numerical Calculation ◽  
Lie Group ◽  
Dynamic Models ◽  
Lagrange Equation ◽  
Kinematic Parameter ◽  
Model Complexity ◽  
Calculation Error ◽  
Closed Chain ◽  
Complex Mechanisms ◽  
The Relationship

The kinematic and dynamic models of robots with complex mechanisms such as the closed-chain mechanism and the branch mechanism are often very complex and difficult to be calculated. Aiming at this issue, in this paper, the pose of the component in robots is represented by the Euclidean group and its subgroups with the proposed method. The component’s velocity is derived using the relationship between the Lie group and Lie algebra, and the acceleration and Jacobian matrix are then derived on this basis. The Lagrange equation is expressed by the obtained kinematic parameter expressions. Establishing the model with this method can obtain clear physical meaning and make the expressions uniform and easy to program, which is convenient for computer-aided calculation and parameterization. Calculating by the properties of the Lie group can reduce the calculation and model complexity, especially for calculating the velocity and acceleration, which reduces the calculation error and eases the calculation. Therefore, the proposed modeling and calculation method of kinematics and dynamics of robots is especially suitable for robots with complex mechanisms. As an example, the kinematic and dynamic model of the manipulator developed in our laboratory is established and a working process of it is numerically calculated. Then, the results of the numerical calculation are compared with the results of virtual prototype simulation in ADAMS to verify the correctness.

Identification of a Simulation Model and a Control Model for a Coke Oven Battery Operating Under Transient Conditions

1992 ◽  
Vol 114 (3) ◽  
pp. 444-453
Author(s):  
C. Be´nard ◽  
M.-M. Rosset-Loue¨rat
Keyword(s):  
Dynamic Models ◽  
Coke Oven ◽  
Power Input ◽  
Operating Conditions ◽  
State Variables ◽  
Elementary Model ◽  
Factors Affecting ◽  
Knowing That ◽  
The Relationship ◽  
Temperature Output

This work addresses the problem of identifying a model of a coke oven plant that would allow its control under unsteady operating conditions. Knowing that coal thermal kinetics in the oven are the most significant factors affecting the resulting coke quality, considering that control is global since all the heating chambers of a battery are supplied by the same feeder, and that constraints arising in the process involve local and global variables, our study is based on the use of two dynamic models: a detailed elementary model of one oven and a global model of the plant. The first model is deduced from a detailed physical model and gives, for an elementary oven, the relationship between the heating power input and the coke temperature output or coke-gas yield indicator. It is tested by comparison with measurement performed at the Sollac-Fos plant. The second model is a lumped state representation that describes, with a few state variables, the evolution of the two batteries. Its parameters are identified with the help of measurements performed at the Sollac-Fos plant.

scholarly journals Design and Mechanical Analysis of Bionic Foldable Beetle Wings

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Caidong Wang ◽  
Chen Wang ◽  
Yu Ning ◽  
Lumin Chen ◽  
Xinjie Wang
Keyword(s):  
Dihedral Angle ◽  
Dynamic Models ◽  
Kinematic Model ◽  
Mechanical Analysis ◽  
Physical Parameters ◽  
Flight Performance ◽  
Motion Simulation ◽  
Flexible Wings ◽  
The Relationship ◽  
Novel Design

In order to improve the flight performance of collapsible aircrafts, a novel mechanism of bionic foldable wings of beetle is designed based on the four-plate mechanism theory. The folding and unfolding movements of the bionic foldable wings are driven by motor and torsion hinges. Based on the D-H method, a kinematic model of wings is established to analyze the dihedral angle of adjacent plates. The folding ratio of an area in different plate creasing angles has been derived and calculated. Utilizing the kinematic and static models produced, as well as considering the folding ratio and output motor torque, the optimal physical parameters of folding wings are obtained. Dynamic models of rigid and flexible wings were established using ADAMS, and a motion simulation was performed. The relationship between dihedral angle and torque during the folding process of both rigid and flexible wings was obtained. The results provide a better understanding of the folding mechanism through the formulation of rigid-flexible wing analysis, as well as demonstrating a novel design of insect-mimicking artificial wings for small aerial vehicles.

Sign in / Sign up

Export Citation Format

Share Document