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Modelling Process (modelling + process)
Selected AbstractsAutomatic muscle generation for character skin deformationCOMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3-4 2006Xiaosong Yang Abstract As skin shape depends on the underlying anatomical structure, the anatomy-based techniques usually afford greater realism than the traditional skeleton-driven approach. On the downside, however, it is against the current animation workflow, as the animator has to model many individual muscles before the final skin layer arrives, resulting in an unintuitive modelling process. In this paper, we present a new anatomy-based technique that allows the animator to start from an already modelled character. Muscles having visible influence on the skin shape at the rest pose are extracted automatically by studying the surface geometry of the skin. The extracted muscles are then used to deform the skin in areas where there exist complex deformations. The remaining skin areas, unaffected or hardly affected by the muscles, are handled by the skeleton-driven technique, allowing both techniques to play their strengths. In order for the extracted muscles to produce realistic local skin deformation during animation, muscle bulging and special movements are both represented. Whereas the former ensues volume preservation, the latter allows a muscle not only to deform along a straight path, but also to slide and bend around joints and bones, resulting in the production of sophisticated muscle movements and deformations. Copyright © 2006 John Wiley & Sons, Ltd. [source] A PCA-based modelling technique for predicting environmental suitability for organisms from presence recordsDIVERSITY AND DISTRIBUTIONS, Issue 1-2 2001M. P. Robertson We present a correlative modelling technique that uses locality records (associated with species presence) and a set of predictor variables to produce a statistically justifiable probability response surface for a target species. The probability response surface indicates the suitability of each grid cell in a map for the target species in terms of the suite of predictor variables. The technique constructs a hyperspace for the target species using principal component axes derived from a principal components analysis performed on a training dataset. The training dataset comprises the values of the predictor variables associated with the localities where the species has been recorded as present. The origin of this hyperspace is taken to characterize the centre of the niche of the organism. All the localities (grid-cells) in the map region are then fitted into this hyperspace using the values of the predictor variables at these localities (the prediction dataset). The Euclidean distance from any locality to the origin of the hyperspace gives a measure of the ,centrality' of that locality in the hyperspace. These distances are used to derive probability values for each grid cell in the map region. The modelling technique was applied to bioclimatic data to predict bioclimatic suitability for three alien invasive plant species (Lantana camara L., Ricinus communis L. and Solanum mauritianum Scop.) in South Africa, Lesotho and Swaziland. The models were tested against independent test records by calculating area under the curve (AUC) values of receiver operator characteristic (ROC) curves and kappa statistics. There was good agreement between the models and the independent test records. The pre-processing of climatic variable data to reduce the deleterious effects of multicollinearity, and the use of stopping rules to prevent overfitting of the models are important aspects of the modelling process. [source] Modelling for an expert system and a parameter validation methodEXPERT SYSTEMS, Issue 5 2002A. Chatzinikolaou A model,based engineering diagnostic method is typically based on the evaluation of the residuals generated from a comparison of important variable values from a simulated system and the corresponding measured values from the system's performance. Consequently, a model should describe the dynamic behaviour of the system as accurately as possible using suitably selected parameter values. This implies the need for validation of the performance of the model by comparison with the measurements of the actual system. This process is especially important when the detection of faults is performed in real,time conditions. In this paper, the modelling process for hydraulic systems as well as a new parameter validation method that has been developed using the DASYLab data acquisition and control software for the estimation of the uncertain parameter values of the model is presented. This model validation process led to the establishment of a model,based expert system that is able to diagnose real,time faults working in parallel with actual dynamic industrial automated processes. [source] Advances in the application of the SWAT model for water resources managementHYDROLOGICAL PROCESSES, Issue 3 2005R. Jayakrishnan Abstract Developments in computer technology have revolutionized the study of hydrologic systems and water resources management. Several computer-based hydrologic/water quality models have been developed for applications in hydrologic modelling and water resources studies. Distributed parameter models, necessary for basin-scale studies, have large input data requirements. Geographic information systems (GIS) and model,GIS interfaces aid the efficient creation of input data files required by such models. One such model available for the water resources professional is the Soil and Water Assessment Tool (SWAT), a distributed parameter model developed by the United States Department of Agriculture. This paper describes some recent advances made in the application of SWAT and the SWAT,GIS interface for water resources management. Four case studies are presented. The Hydrologic Unit Model for the United States (HUMUS) project used SWAT to conduct a national-scale analysis of the effect of management scenarios on water quantity and quality. Integration of the SWAT model with rainfall data available from the WSR-88D radar network helps us to incorporate the spatial variability of rainfall into the modelling process. This study demonstrates the usefulness of radar rainfall data in distributed hydrologic studies and the potential of SWAT for application in flood analysis and prediction. A hydrologic modelling study of the Sondu river basin in Kenya using SWAT indicates the potential for application of the model in African watersheds and points to the need for development of better model input data sets in Africa, which are critical for detailed water resources studies. The application of SWAT for water quality analysis in the Bosque river basin, Texas demonstrates the strength of the model for analysing different management scenarios to minimize point and non-point pollution, and its potential for application in total maximum daily load (TMDL) studies. Copyright © 2005 John Wiley & Sons, Ltd. [source] The Importance of Role Models and Demographic Context for Senior Women's Work Identity DevelopmentINTERNATIONAL JOURNAL OF MANAGEMENT REVIEWS, Issue 3 2010Ruth H.V. Sealy The lack of senior female role models continues to be cited as a key barrier to women's career success. Yet there is little academic research into the gendered aspects of role modelling in organizations, or the utility of role models at a senior level. The paper starts with a review of papers examining the construction of role models in organizational settings. This leads to the inclusion of two related areas , organizational demographics as the contextual factor affecting the availability of role models and how they are perceived, and work identity formation as a possible key explanatory factor behind the link between the lack of senior female role models and the lack of career progression to top organizational levels. The literature looking at social theories of identity formation is then considered from a gender perspective. The key gaps identified are that while the behavioural value of role models has been well documented, a better understanding is needed of how gender and organizational demography influence the role modelling process. Importantly, the symbolic value and possibly other values of female role models in the identity construction of senior women require further in-depth investigation. Finally, this review calls for a more integrated approach to the study of role models and work identity formation, pulling together literatures on organizational demography, the cognitive construal of role models and their importance for successful work identity formation in senior women. [source] A standardized and reliable method to apply the Global Assessment of Functioning (GAF) scale to psychiatric case recordsINTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 2 2000Dr M. Mirandola Abstract The Global Assessment of Functioning (GAF) scale is widely used both in routine clinical practice and in research. However, its reliability has never been assessed when used to rate information in clinical records. The present study focuses on the development of a standardized method (an ongoing modelling process between raters) for establishing desired levels of inter-rater reliability (IRR) in the application of the GAF to psychiatric case records. Fifty-one patients at first-ever contact with mental health services were included in the study. They were selected from a total sample of 662 first-ever patients by using a systematic sampling. Three raters (resident psychiatrists at their third year of training) took part in a 12-hour training programme, during which they were asked to assess the global psychological functioning of patients, taking into account information recorded in case records. The extent of agreement between raters was estimated by applying the ,limits of agreement' method and the ,concordance correlation coefficient'. The training programme proved to be feasible, easy to administer and acceptable to psychiatrists in training with limited previous experience of using rating scales. Very high levels of concordance (all greater than 0.95) emerged between the three raters. The GAF, completed using information from case records included in the initial assessment form, appeared to be a reliable instrument, even when used by clinical psychiatrists in training. Copyright © 2000 Whurr Publishers Ltd. [source] On the structural stability of thermoelastic model of porous mediaMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 1 2008Stan Chiri Abstract In the present paper we study the structural stability of the mathematical model of the linear thermoelastic materials with voids. We prove that the solutions of problems depend continuously on the constitutive quantities, which may be subjected to error or perturbations in the mathematical modelling process. Thus, we assume to have changes in the various coupling coefficients of the model and then we establish estimates of continuous dependence of solutions. We have to outline that such estimates play a central role in obtaining approximations to these kinds of problems. To derive a priori estimates for a solution we first establish appropriate bounds for the solutions of certain auxiliary problems. These are achieved by means of so-called Rellich-like identities. We also investigate how the solution in the coupled model behaves as some coupling coefficients tend to zero. Copyright © 2007 John Wiley & Sons, Ltd. [source] Knowledge-based Diagnosis Aiding in Regulation ThermographyPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2003Hagen Knaf Dr. Regulation Thermography is a diagnostic tool in the medical science based on the measurement of the body's thermoregulation ability , the so-called thermogram. The expert's rules for the interpretation of a thermogram can be modelled using Fuzzy Logic. In the present article this modelling process is briefly explained; it leads to a Fuzzy Inference System capable of evaluating thermograms with respect to e.g. signals for the presence of Breast Cancer. Some of the main points of a comparison between the expert rules and the result of a stepwise linear discriminant analysis performed on classified thermograms are presented. [source] ELICITING A DIRECTED ACYCLIC GRAPH FOR A MULTIVARIATE TIME SERIES OF VEHICLE COUNTS IN A TRAFFIC NETWORKAUSTRALIAN & NEW ZEALAND JOURNAL OF STATISTICS, Issue 3 2007Catriona M. Queen Summary The problem of modelling multivariate time series of vehicle counts in traffic networks is considered. It is proposed to use a model called the linear multiregression dynamic model (LMDM). The LMDM is a multivariate Bayesian dynamic model which uses any conditional independence and causal structure across the time series to break down the complex multivariate model into simpler univariate dynamic linear models. The conditional independence and causal structure in the time series can be represented by a directed acyclic graph (DAG). The DAG not only gives a useful pictorial representation of the multivariate structure, but it is also used to build the LMDM. Therefore, eliciting a DAG which gives a realistic representation of the series is a crucial part of the modelling process. A DAG is elicited for the multivariate time series of hourly vehicle counts at the junction of three major roads in the UK. A flow diagram is introduced to give a pictorial representation of the possible vehicle routes through the network. It is shown how this flow diagram, together with a map of the network, can suggest a DAG for the time series suitable for use with an LMDM. [source] Directional asymmetry of long-distance dispersal and colonization could mislead reconstructions of biogeographyJOURNAL OF BIOGEOGRAPHY, Issue 5 2005Lyn G. Cook Abstract Aim, Phylogenies are increasingly being used to attempt to answer biogeographical questions. However, a reliance on tree topology alone has emerged without consideration of earth processes or the biology of the organisms in question. Most ancestral-state optimization methods have inherent problems, including failure to take account of asymmetry, such as unequal probabilities of losses and gains, and the lack of use of independent cost estimates. Here we discuss what we perceive as shortcomings in most current tree-based biogeography interpretation methods and show that consideration of processes and their likelihoods can turn the conventional biogeographical interpretation on its head. Location, Southern hemisphere focus but applicable world-wide. Methods, The logic of existing methods is reviewed with respect to their adequacy in modelling processes such as geographical mode of speciation and likelihood of dispersal, including directional bias. Published reconstructions of dispersal of three plant taxa between Australia and New Zealand were re-analysed using standard parsimony and maximum likelihood (ML) methods with rate matrices to model expected asymmetry of dispersal. Results, Few studies to date incorporate asymmetric dispersal rate matrices or question the simplistic assumption of equal costs. Even when they do, cost matrices typically are not derived independently of tree topology. Asymmetrical dispersal between Australia and New Zealand could be reconstructed using parsimony but not with ML. Main conclusions, The inadequacy of current models has important consequences for our interpretation of southern hemisphere biogeography, particularly in relation to dispersal. For example, if repeated directional dispersals and colonization in the direction of prevailing winds have occurred, with intervening periods of speciation, then there is no need to infer dispersals against those winds. Failure to take account of directionality and other biases in reconstruction methods has implications beyond the simple misinterpretation of the biogeography of a taxonomic group, such as calibration of molecular clocks, the dating of vicariance events, and the prioritization of areas for conservation. [source] | |||||||||||||