INVESTIGATION OF RETAINING WALL INSTALLATION AND PERFORMANCE USING CENTRIFUGE MODELLING TECHNIQUES.

1998 ◽  
Vol 131 (3) ◽  
pp. 163-170 ◽  
Author(s):  
D J RICHARDS ◽  
W POWRIE ◽  
J R T PAGE
Keyword(s):  
Retaining Wall ◽  
Centrifuge Modelling ◽  
Modelling Techniques ◽  
And Performance

Drought forecasting: A review of modelling approaches 2007–2017

2019 ◽  
Vol 11 (3) ◽  
pp. 771-799 ◽  
Author(s):  
K. F. Fung ◽  
Y. F. Huang ◽  
C. H. Koo ◽  
Y. W. Soh
Keyword(s):  
Evaluation Criteria ◽  
Dynamic Modelling ◽  
Negative Consequences ◽  
Drought Forecasting ◽  
Modelling Techniques ◽  
Input Variables ◽  
And Performance ◽  
Resources Planning ◽  
Selection Of ◽  
Modelling Approaches

Abstract Droughts are prolonged precipitation-deficient periods, resulting in inadequate water availability and adverse repercussions to crops, animals and humans. Drought forecasting is vital to water resources planning and management in minimizing the negative consequences. Many models have been developed for this purpose and, indeed, it would be a long process for researchers to select the best suited model for their research. A timely, thorough and informative overview of the models' concepts and historical applications would be helpful in preventing researchers from overlooking the potential selection of models and saving them considerable amounts of time on the problem. Thus, this paper aims to review drought forecasting approaches including their input requirements and performance measures, for 2007–2017. The models are categorized according to their respective mechanism: regression analysis, stochastic, probabilistic, artificial intelligence based, hybrids and dynamic modelling. Details of the selected papers, including modelling approaches, authors, year of publication, methods, input variables, evaluation criteria, time scale and type of drought are tabulated for ease of reference. The basic concepts of each approach with key parameters are explained, along with the historical applications, benefits and limitations of the models. Finally, future outlooks and potential modelling techniques are furnished for continuing drought research.

scholarly journals On the Impact of Additive Manufacturing Processes Complexity on Modelling

2021 ◽  
Vol 11 (16) ◽  
pp. 7743
Author(s):  
Panagiotis Stavropoulos ◽  
Panagis Foteinopoulos ◽  
Alexios Papapacharalampopoulos
Keyword(s):  
Additive Manufacturing ◽  
Performance Indicators ◽  
Part Quality ◽  
Build Time ◽  
Modelling Techniques ◽  
And Performance ◽  
The Many ◽  
Process Complexity ◽  
The Impact ◽  
Am Processes

The interest in additive manufacturing (AM) processes is constantly increasing due to the many advantages they offer. To this end, a variety of modelling techniques for the plethora of the AM mechanisms has been proposed. However, the process modelling complexity, a term that can be used in order to define the level of detail of the simulations, has not been clearly addressed so far. In particular, one important aspect that is common in all the AM processes is the movement of the head, which directly affects part quality and build time. The knowledge of the entire progression of the phenomenon is a key aspect for the optimization of the path as well as the speed evolution in time of the head. In this study, a metamodeling framework for AM is presented, aiming to increase the practicality of simulations that investigate the effect of the movement of the head on part quality. The existing AM process groups have been classified based on three parameters/axes: temperature of the process, complexity, and part size, where the complexity has been modelled using a dedicated heuristic metric, based on entropy. To achieve this, a discretized version of the processes implicated variables has been developed, introducing three types of variable: process parameters, key modeling variables and performance indicators. This can lead to an enhanced roadmap for the significance of the variables and the interpretation and use of the various models. The utilized spectrum of AM processes is discussed with respect to the modelling types, namely theoretical/computational and experimental/empirical.

Performance Studies of Passive Damping Techniques Used to Suppress Combustion Oscillations in LPP Combustors

2003 ◽  
Author(s):  
G. J. M. Sims ◽  
R. W. Copplestone ◽  
J. R. Tilston
Keyword(s):  
Performance Studies ◽  
Structural Damage ◽  
High Amplitude ◽  
Direct Result ◽  
Passive Damping ◽  
Helmholtz Resonators ◽  
Acoustic Modelling ◽  
Quarter Wave ◽  
Modelling Techniques ◽  
And Performance

As part of an EU Framework IV programme, an investigation was undertaken into the design and performance of a variety of passive damping techniques aimed at reducing or eliminating combustion oscillations in an LPP combustor. Earlier in the programme, internal mapping of a 3-sector LPP combustor had to be temporarily suspended when significant structural damage was incurred as a result of high amplitude combustion oscillations. As a direct result, a review was undertaken to investigate damping technologies that were suitable for use within a combustion environment. Acoustic modelling techniques were used to support initial laboratory studies to establish linear absorber design rules. Following these studies, Helmholtz resonators, quarter wave tubes and a bulk absorber were tested in an experimental LPP combustor at atmospheric pressure. Attention was focussed on broadening the attenuation bandwidth whilst maintaining suitable damping performance. The bulk absorber achieved acoustic pressure reductions of up to 50%, whereas an array of combustor head mounted Helmholtz resonators achieved up to 90% pressure reduction.

Questioning the General Self-Esteem Vaccine: General Self-Esteem, Racial Discrimination, and Standardised Achievement Across Indigenous and Non-Indigenous Students

2010 ◽  
Vol 20 (1) ◽  
pp. 1-21 ◽  
Author(s):  
Gawaian H. Bodkin-Andrews ◽  
Marjorie Seaton ◽  
Genevieve F. Nelson ◽  
Rhonda G. Craven ◽  
Alexander S. Yeung
Keyword(s):  
Racial Discrimination ◽  
Structural Equation ◽  
Negative Impact ◽  
Self Esteem ◽  
Psychological Research ◽  
Positive Influence ◽  
Indigenous Australian ◽  
Indigenous Students ◽  
Modelling Techniques ◽  
And Performance

AbstractPsychological research and the popular media culture have repeatedly noted that self-esteem positively contributes to life satisfaction and performance indicators across a large variety of domains. However, while varying measures of self-esteem may be argued to have a positive influence on outcome measures, increasing evidence suggests that perceptions of racial discrimination may also have a negative impact across a wide variety of outcomes. The current investigation used structural equation modelling techniques to examine the potential impact of Indigenous and non-Indigenous Australian students' General Self-Esteem and their perceptions of racial discrimination on spelling and maths achievement. Results indicated that General Self-Esteem displayed little or no significant relations with the performance measures, yet perceived racial discrimination significantly and negatively predicted both spelling and maths achievement for the Indigenous and non-Indigenous students. In addition, no significant latent interaction between General Self-Esteem and perceived discrimination was identified, raising questions for the self-protective properties of General Self-Esteem, at least for achievement outcomes.

Geometry and visual realism of ship models for digital ship bridge simulators

2016 ◽  
Vol 231 (1) ◽  
pp. 329-341
Author(s):  
Jose Miguel Varela ◽  
C. Guedes Soares
Keyword(s):  
Virtual Environments ◽  
Three Dimensional ◽  
Ocean Engineering ◽  
Modelling Techniques ◽  
Marine Technology ◽  
And Performance ◽  
Visual Realism ◽  
The University

This article addresses the main requirements and the process of creating the geometry of ship models that fulfil the highly demanding request for realism and performance of the virtual environments currently used in modern ship bridge simulators. It starts with a classification of the ships based on their role in the simulation and on the type of simulator used, and defines the main characteristics of the models. It also discusses the importance of a well-defined workflow and its impact on the modelling time and on the quality of the final product. The article provides contributions in the following areas: identification of the main requirements of polygonal models of ships for ship simulators; effective workflow for ship three-dimensional modelling and identification of most suitable modelling techniques for efficient creation of ship models. The study is supported by real examples of three-dimensional modelling of ships with different sizes and characteristics currently used by the ship manoeuvring simulator in the Centre for Marine Technology and Ocean Engineering of the University of Lisbon.

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