Point mass impulse-momentum model of the equine rotational fall

2019 ◽  
Vol 15 (3) ◽  
pp. 157-165
Author(s):  
M.H. Foreman ◽  
J.R. Engsberg ◽  
J.H. Foreman
Keyword(s):  
Point Mass ◽  
Future Research ◽  
Collision Time ◽  
Mass Model ◽  
Impact Forces ◽  
Force Transfer ◽  
Reference Curves ◽  
Key Variables ◽  
Cross Country ◽  
Input Variables

Rotational falls are a serious cause of injury and death to horse and rider, particularly in the cross-country phase of eventing. The forces involved when horses galloping cross-country strike an immovable fence are unknown. The objective of this study was to mathematically model those forces using existing kinematic data measured from jumping horses. Data were obtained from published research using motion capture to measure mechanics about the center of gravity of the jumping horse at take-off. A convenience method from video evidence of rotational falls was used to estimate time of collision (Δt). A point mass model using equations of impulse-momentum and incorporating key variables was systematically implemented in Matlab (r2016a). The mean collision time (Δt=0.79s) produced horizontal, vertical, and resultant impact forces of 8,580, 8,245, and 12,158 N, respectively. Reference curves of impact forces were created for ranges of relevant input variables including collision time. Proportional relationships showed that shorter impact duration led to higher magnitude of force transfer between horse and obstacle. This study presents a preliminary range of collision forces based on a simplified model and numerous assumptions related to input variables. Future research should work to build upon these estimates through more complex modelling and data collection to enhance applicability for the design of cross-country safety devices.

A point-mass model of gibbon locomotion

1999 ◽  
Vol 202 (19) ◽  
pp. 2609-2617 ◽  
Author(s):  
J.E. Bertram ◽  
A. Ruina ◽  
C.E. Cannon ◽  
Y.H. Chang ◽  
M.J. Coleman
Keyword(s):  
Energy Exchange ◽  
Forest Canopy ◽  
Mechanical Energy ◽  
Single Point ◽  
Metabolic Cost ◽  
Point Mass ◽  
Mass Model ◽  
Natural Behavior ◽  
Continuous Contact ◽  
Mechanical Factors

In brachiation, an animal uses alternating bimanual support to move beneath an overhead support. Past brachiation models have been based on the oscillations of a simple pendulum over half of a full cycle of oscillation. These models have been unsatisfying because the natural behavior of gibbons and siamangs appears to be far less restricted than so predicted. Cursorial mammals use an inverted pendulum-like energy exchange in walking, but switch to a spring-based energy exchange in running as velocity increases. Brachiating apes do not possess the anatomical springs characteristic of the limbs of terrestrial runners and do not appear to be using a spring-based gait. How do these animals move so easily within the branches of the forest canopy? Are there fundamental mechanical factors responsible for the transition from a continuous-contact gait where at least one hand is on a hand hold at a time, to a ricochetal gait where the animal vaults between hand holds? We present a simple model of ricochetal locomotion based on a combination of parabolic free flight and simple circular pendulum motion of a single point mass on a massless arm. In this simple brachiation model, energy losses due to inelastic collisions of the animal with the support are avoided, either because the collisions occur at zero velocity (continuous-contact brachiation) or by a smooth matching of the circular and parabolic trajectories at the point of contact (ricochetal brachiation). This model predicts that brachiation is possible over a large range of speeds, handhold spacings and gait frequencies with (theoretically) no mechanical energy cost. We then add the further assumption that a brachiator minimizes either its total energy or, equivalently, its peak arm tension, or a peak tension-related measure of muscle contraction metabolic cost. However, near the optimum the model is still rather unrestrictive. We present some comparisons with gibbon brachiation showing that the simple dynamic model presented has predictive value. However, natural gibbon motion is even smoother than the smoothest motions predicted by this primitive model.

Discussion of “How Does Culture Impinge Upon Managers’ Demeanor of Earnings Management? Evidence From Cross-Country Analysis”

2021 ◽  
pp. 2180006
Author(s):  
Suresh Radhakrishnan ◽  
Surya Janakiraman
Keyword(s):  
Earnings Management ◽  
National Culture ◽  
Corporate Culture ◽  
Reference Points ◽  
Future Research ◽  
Economic Institutions ◽  
Country Analysis ◽  
Cross Country

We provide a framework that builds upon the findings of Chaney, Lodh and Nandy (2021) for future research to examine the mechanism through which national culture is related to earnings management. In particular, the framework can be used to examine how specific contexts, reference points, corporate culture and economic institutions affect the relation between national culture and earnings management.

Multipole Expansion Model in Gravitional Lensing

1997 ◽  
Vol 06 (04) ◽  
pp. 425-447 ◽  
Author(s):  
Takeshi Fukuyama ◽  
Yuuko Kakigi ◽  
Takashi Okamura
Keyword(s):  
Power Law ◽  
Catastrophe Theory ◽  
Multipole Expansion ◽  
Point Mass ◽  
Mass Model ◽  
Expansion Model ◽  
Best Fit

Nontransparent models of the multipole expansion model and the two point-mass model are analyzed from the catastrophe theory. Singularity behaviours of 2n-pole moments are discussed. We apply these models to the triple quasar PG1115+080 and compare with the typical transparent model, softened power law spheroids. The multipole expansion model gives the best fit among them.

Development of a Research Framework for Green IT Enablers Using Interpretive Structural Modelling

2019 ◽  
pp. 365-378
Author(s):  
Sania Khan ◽  
Abdul Razak Honnutagi ◽  
Mohammed Shahid Ahamed Khan
Keyword(s):  
Future Research ◽  
Structural Modelling ◽  
Green It ◽  
Enabling Factors ◽  
Interpretive Structural Modelling ◽  
Sustainable Procurement ◽  
Strategic Model ◽  
Key Variables ◽  
Green Purchasing ◽  
Corporate Social

The purpose of this paper is to identify the key variables and develop the relationships among the green IT enabling factors which drive consumers towards green purchasing. In this paper Delphi technique and Interpretive structural modelling approach have been employed to model the identified factors. These variables are segregated as ‘enablers' that facilitate corporate consumers' to purchase eco-friendly IT products. The major finding of this research is power consumption, e-wastage disposal, product performance and global warming are underlined as significantly important enablers which also drives other factors. The variables are interpreted for sustainable procurement in terms of their driving and dependence powers. For true sustainability the corporate organisations should focus on considering environmental consciousness, Kyoto protocol, corporate social responsibility and eco-label certified products as main interest for green purchasing. Developing the present strategic model and validating it scientifically are further suggested as directions for future research.

scholarly journals Predicting the Electrical Energy Consumption of Electric Arc Furnaces Using Statistical Modeling

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 959 ◽  
Author(s):  
Leo S. Carlsson ◽  
Peter B. Samuelsson ◽  
Pär G. Jönsson
Keyword(s):  
Statistical Modeling ◽  
Statistical Models ◽  
Linear Models ◽  
Nonlinear Models ◽  
Electrical Energy ◽  
Electric Arc ◽  
Future Research ◽  
Published Data ◽  
Industrial Setting ◽  
Input Variables

Statistical modeling, also known as machine learning, has gained increased attention in part due to the Industry 4.0 development. However, a review of the statistical models within the scope of steel processes has not previously been conducted. This paper reviews available statistical models in the literature predicting the Electrical Energy (EE) consumption of the Electric Arc Furnace (EAF). The aim was to structure published data and to bring clarity to the subject in light of challenges and considerations that are imposed by statistical models. These include data complexity and data treatment, model validation and error reporting, choice of input variables, and model transparency with respect to process metallurgy. A majority of the models are never tested on future heats, which essentially renders the models useless in a practical industrial setting. In addition, nonlinear models outperform linear models but lack transparency with regards to which input variables are influencing the EE consumption prediction. Some input variables that heavily influence the EE consumption are rarely used in the models. The scrap composition and additive materials are two such examples. These observed shortcomings have to be correctly addressed in future research applying statistical modeling on steel processes. Lastly, the paper provides three key recommendations for future research applying statistical modeling on steel processes.

scholarly journals Asthma in Competitive Cross-Country Skiers: A Systematic Review and Meta-analysis

2020 ◽  
Vol 50 (11) ◽  
pp. 1963-1981
Author(s):  
Rikhard Mäki-Heikkilä ◽  
Jussi Karjalainen ◽  
Jari Parkkari ◽  
Maarit Valtonen ◽  
Lauri Lehtimäki
Keyword(s):  
Systematic Review ◽  
Meta Analysis ◽  
Medication Use ◽  
Asthma Medication ◽  
Future Research ◽  
Bronchial Biopsy ◽  
Qualitative Synthesis ◽  
Eosinophilic Asthma ◽  
Airway Infections ◽  
Cross Country

Abstract Introduction In cross-country skiing, the repetitive ventilation of large amounts of cold and dry air strains the airways. The aim of this systematic review was to establish an overview of the current literature on asthma in cross-country skiers, biathletes and ski-orienteers. Methods Six databases were searched on August 29, 2019. The search yielded 2161 articles. Thirty articles fulfilled the search criteria and were pooled together for a qualitative synthesis. Eight articles were included in the meta-analysis on the prevalence of asthma and the use of asthma medication. Results According to the meta-analysis, the prevalence of self-reported physician-diagnosed asthma in skiers was 21% (95% CI 14–28%). The onset age of asthma was higher in skiers than in non-skiers with asthma. The prevalence of asthma medication use was on average 23% (CI 95% 19–26%). Several studies reported that asthma was underdiagnosed in skiers, as previously healthy skiers without a prior asthma diagnosis or medication use were frequently found to fulfill diagnostic criteria for asthma according to lung function tests. Studies using bronchial biopsy demonstrated that eosinophilic asthma is not detected in skiers with asthma as often as it is in non-skiers with asthma and that there are signs of airway inflammation even in non-asthmatic skiers. Conclusion Our findings suggest that the accuracy and coverage of diagnosing asthma in skiers has improved over the recent decades. However, the optimal treatment and natural course of asthma in this population remain unclear. Future research should investigate how the intensity of training, airway infections and their treatment affect the development of asthma among skiers. PRD registration number CRD42017070940.

FORECASTING FOREIGN EXCHANGE RATES WITH ARTIFICIAL NEURAL NETWORKS: A REVIEW

2004 ◽  
Vol 03 (01) ◽  
pp. 145-165 ◽  
Author(s):  
WEI HUANG ◽  
K. K. LAI ◽  
Y. NAKAMORI ◽  
SHOUYANG WANG
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Exchange Rates ◽  
Network Architecture ◽  
Future Research ◽  
Promising Alternative ◽  
Practical Applications ◽  
Future Research Directions ◽  
Artificial Neural ◽  
Input Variables

Forecasting exchange rates is an important financial problem that is receiving increasing attention especially because of its difficulty and practical applications. Artificial neural networks (ANNs) have been widely used as a promising alternative approach for a forecasting task because of several distinguished features. Research efforts on ANNs for forecasting exchange rates are considerable. In this paper, we attempt to provide a survey of research in this area. Several design factors significantly impact the accuracy of neural network forecasts. These factors include the selection of input variables, preparing data, and network architecture. There is no consensus about the factors. In different cases, various decisions have their own effectiveness. We also describe the integration of ANNs with other methods and report the comparison between performances of ANNs and those of other forecasting methods, and finding mixed results. Finally, the future research directions in this area are discussed.

scholarly journals CORPORATE GOVERNANCE, FIRM PERFORMANCE, AND ECONOMIC GROWTH – THEORETICAL ANALYSIS

2016 ◽  
Vol 17 (1) ◽  
pp. 35-51 ◽  
Author(s):  
Marinko ŠKARE ◽  
Tea HASIĆ
Keyword(s):  
Economic Growth ◽  
Corporate Governance ◽  
Growth And Development ◽  
Growth Models ◽  
Theoretical Research ◽  
Future Research ◽  
Research Directions ◽  
Future Research Directions ◽  
Cross Country ◽  
Research Show

Corporate governance in today's modern economies is growing in importance within the growth accounting equation. Although we look at corporate governance as final product of 20/21st century economies, old economic growth theories were aware of its importance for growth and development. Roots of corporate governance go back to the ancient economies of India and Greece also. This paper offers a consistent literature review assessing the nexus between corporate performance and economic growth. Individual and cross-country studies show corporate governance in majority of the cases positively affects firms performance and in turn nations' economic growth. Empirical and theoretical research show corporate governance is an important growth determinant to be reviewed in the field of growth models. This article summarizes main findings providing future research directions on the corporate governance – economic growth nexus.

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