Functionality-Driven Musculature Retargeting

We present a novel retargeting algorithm that transfers the musculature of a reference anatomical model to new bodies with different sizes, body proportions, muscle capability, and joint range of motion while preserving the functionality of the original musculature as closely as possible. The geometric configuration and physiological parameters of musculotendon units are estimated and optimized to adapt to new bodies. The range of motion around joints is estimated from a motion capture dataset and edited further for individual models. The retargeted model is simulation-ready, so we can physically simulate muscle-actuated motor skills with the model. Our system is capable of generating a wide variety of anatomical bodies that can be simulated to walk, run, jump and dance while maintaining balance under gravity. We will also demonstrate the construction of individualized musculoskeletal models from bi-planar X-ray images and medical examinations.Comment: 15 pages, 20 figure

Outside-in

For believable character animation, skin deformation should communicate important deformation effects due to underlying muscle movement. Anatomical models that capture these effects are typically constructed from the in-side out. Internal tissue is modeled by hand and a surface skin is attached to, or generated from, the internal structure. This paper presents an outside–in approach to anatomical modeling, in which we generate musculature from a predefined structure, which we conform to an artist–sculpted skin surface. Motivated by interactive appli-cations, we attach the musculature to an existing control skeleton and apply a novel geometric deformation model to deform the skin surface to capture important muscle motion effects. Musculoskeletal structure can be stored as a template and applied to new character models. We illustrate the methodology, as integrated into a commercial character animation system, with examples driven by both keyframe animation and recorded motion data

A novel musculoskeletal joint modelling for orthopaedic applications

This thesis was submitted for the degree of Docter of Philosophy and awarded by Brunel University.The objective of the work carried out in this thesis was to develop analytical and computational tools to model and investigate musculoskeletal human joints. It was recognised that the FEA was used by many researchers in modelling human musculoskeletal motion, loading and stresses. However the continuum mechanics played only a minor role in determining the articular joint motion, and its value was questionable. This is firstly due to the computational cost and secondly due to its impracticality for this application. On the other hand, there isn’t any suitable software for precise articular joint motion analysis to deal with the local joint stresses or non standard joints. The main requirement in orthopaedics field is to develop a modeller software (and its associated theories) to model anatomic joint as it is, without any simplification with respect to joint surface morphology and material properties of surrounding tissues. So that the proposed modeller can be used for evaluating and diagnosing different joint abnormalities but furthermore form the basis for performing implant insertion and analysis of the artificial joints. The work which is presented in this thesis is a new frame work and has been developed for human anatomic joint analysis which describes the joint in terms of its surface geometry and surrounding musculoskeletal tissues. In achieving such a framework several contributions were made to the 6DOF linear and nonlinear joint modelling, the mathematical definition of joint stiffness, tissue path finding and wrapping and the contact with collision analysis. In 6DOF linear joint modelling, the contribution is the development of joint stiffness and damping matrices. This modelling approach is suitable for the linear range of tissue stiffness and damping properties. This is the first of its kind and it gives a firm analytical basis for investigating joints with surrounding tissue and the cartilage. The 6DOF nonlinear joint modelling is a new scheme which is described for modelling the motion of multi bodies joined by non-linear stiffness and contact elements. The proposed method requires no matrix assembly for the stiffness and damping elements or mass elements. The novelty in the nonlinear modelling, relates to the overall algorithmic approach and handling local non-linearity by procedural means. The mathematical definition of joint stiffness is also a new proposal which is based on the mathematical definition of stiffness between two bodies. Based on the joint stiffness matrix properties, number of joint stiffness invariants was obtained analytically such as the centre of stiffness, the principal translational stiffnesses, and the principal rotational stiffnesses. In corresponding to these principal stiffnesses, their principal axes have been also obtained. Altogether, a joint is assessed by six principal axes and six principal stiffnesses and its centre of stiffness. These formulations are new and show that a joint can be described in terms of inherent stiffness properties. It is expected that these will be better in characterising a joint in comparison to laxity based characterisation. The development of tissue path finding and wrapping algorithms are also introduced as new approaches. The musculoskeletal tissue wrapping involves calculating the shortest distance between two points on a meshed surface. A new heuristic algorithm was proposed. The heuristic is based on minimising the accumulative divergence from the straight line between two points on the surface and the direction of travel on the surface (i.e. bone). In contact and collision based development, the novel algorithm has been proposed that detects possible colliding points on the motion trajectory by redefining the distance as a two dimensional measure along the velocity approach vector and perpendicular to this vector. The perpendicular distance determines if there are potentially colliding points, and the distance along the velocity determines how close they are. The closest pair among the potentially colliding points gives the “time to collision”. The algorithm can eliminate the “fly pass” situation where very close points may not collide because of the direction of their relative velocity. All these developed algorithms and modelling theories, have been encompassed in the developed prototype software in order to simulate the anatomic joint articulations through modelling formulations developed. The software platform provides a capability for analysing joints as 6DOF joints based on anatomic joint surfaces. The software is highly interactive and driven by well structured database, designed to be highly flexible for the future developments. Particularly, two case studies are carried out in this thesis in order to generate results relating to all the proposed elements of the study. The results obtained from the case studies show good agreement with previously published results or model based results obtained from Lifemod software, whenever comparison was possible. In some cases the comparison was not possible because there were no equivalent results; the results were supported by other indicators. The modelling based results were also supported by experiments performed in the Brunel Orthopaedic Research and Learning Centre

Mental stress among civil engineering construction site agents and foremen in the Nelson Mandela Bay Metropole

The civil engineering sector of the construction industry as a whole has been suffering from mental stress due to a lack of stress management interventions, rendering employees vulnerable to burnout, poor mental health, and subject to injury on site. The rationale of this study is to explore the prevalence of mental stress in the civil engineering sector of the construction industry, and the potential causes of stress, vis-à-vis the effects it has on an individual. An empirical study based on a descriptive and analytical survey method was conducted among medium to large civil engineering contractors in the Nelson Mandela Bay Metropole (NMBM). The study adopted the use of questionnaires, and a review of the related literature to effectively summarise and describe the collected field data. The sample stratum included civil engineering site agents and foremen. The salient findings include: high job demands, low job control, and low job social support are contributors to stress; site agents and foremen long for more time spent with family and friends; site agents and foremen are exposed to various physical, organisational and socio-economic stressors; site agents and foremen are displaying coping strategies unsupportive of a healthy lifestyle; there is a lack of awareness of stress management in the civil engineering sector of the construction industry; the level of stress experienced by site agents and foremen is rated as a lesser extent; the prevalence of depression among site agents and foremen is rated as a lesser extent; site agents and foremen are at risk of injury due to feeling stressed, and site agents and foremen are exposed to a range of musculoskeletal disorders (MSDs) due to poor ergonomics, and possibly stress too. It can be concluded that stress negatively affects the civil engineering sector of the construction industry by, inter alia, increased employee absence, injuries and accidents, higher staff turnover, depression, and lower levels of production. Furthermore, stress may lead to eventual burnout, rendering an individual at a significantly higher risk of developing physical health complications. Recommendations include: organisations to address the problem of work-family imbalance, by providing more time off to spend with family and loved ones. v Organisations need to promote and implement internal coping strategies, to assist those who are facing strain to effectively deal with their stress. More support from line managers to employees should be provided, as this will increase their resources in terms of job support, job demand, and job control in their working environment. Also, organisations need to promote teambuilding activities and exercise among their employees. Lastly, organisational policy and government legislation need to be revised in the long term, to provide for individual mental wellbeing, and reduced occupational stress

3D modeling of the human upper limb including the biomechanics of joints, muscles and soft tissues

The challenge in virtual human modeling is to achieve the representation of the main human characteristics with as much realism as possible. Such achievements would allow the simulation and/or analysis of many virtual situations involving humans. Simulation is especially useful to derive information from the models so as to predict and/or reproduce the behaviors that would be observed in real situations. Computer methods in visualization and simulation have thus great potential for advances in medicine. The processes of strength generation and motion coordination are some of these phenomena for which there is still much remaining to be understood. The human shoulder is also probably the articulation of the human body which deserves more than any other to be named "terra incognita". Investigations towards the biomechanical modeling and simulation of the human upper limb are therefore presented in this study. It includes thorough investigation into the musculoskeletal anatomy and biomechanics of the human upper limb, into the biomechanical constitutive modeling of muscles and soft tissues, and into the nonlinear continuum mechanics and numerical methods, especially the incremental finite element methods, necessary for their simulation. On this basis, a 3-D biomechanical musculoskeletal human upper limb model has been designed using the Visible Human Data provided by the U.S. National Library of Medicine, and applied to the dynamic musculoskeletal simulation of the human upper limb. This research has been achieved in the context of the EU ESPRIT Project CHARM, whose objective has been to develop a comprehensive human animation resource database and a set of software tools allowing the modeling of the human complex musculoskeletal system and the simulation of its dynamics, including the finite element simulation of soft tissue deformation and muscular contraction. An investigation towards the application of this knowledge for the realistic modeling and animation of the upper limb in computer animation is then presented. The anatomical and biomechanical modeling of the scapulo-thoracic constraint and the shoulder joint sinus cones are proposed and applied to the realistic animation, using inverse kinematics, of a virtual skeleton and an anatomic musculoskeletal body model

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): Guidelines for medical 3D printing and appropriateness for clinical scenarios

Este número da revista Cadernos de Estudos Sociais estava em organização quando fomos colhidos pela morte do sociólogo Ernesto Laclau. Seu falecimento em 13 de abril de 2014 surpreendeu a todos, e particularmente ao editor Joanildo Burity, que foi seu orientando de doutorado na University of Essex, Inglaterra, e que recentemente o trouxe à Fundação Joaquim Nabuco para uma palestra, permitindo que muitos pudessem dialogar com um dos grandes intelectuais latinoamericanos contemporâneos. Assim, buscamos fazer uma homenagem ao sociólogo argentino publicando uma entrevista inédita concedida durante a sua passagem pelo Recife, em 2013, encerrando essa revista com uma sessão especial sobre a sua trajetória

Topics in construction safety and health : ergonomic hazards and WMSDs : an interdisciplinary annotated bibliography

"These referenced articles provide literature on construction workers and their risk of ergonomic hazards and work-related musculoskeletal system disorders on the job." - NIOSHTIC-2NIOSHTIC no. 20068246Production of this document was supported by cooperative agreement OH 009762 from the National Institute for Occupational Safety and Health (NIOSH). The contents are solely the responsibility of the authors and do not necessarily represent the official views of NIOSH.Ergonomics-and-WMSDs-annotated-bibliography.pdfcooperative agreement OH 009762 from the National Institute for Occupational Safety and Healt

A Method to Represent Heterogeneous Materials for Rapid Prototyping: The Matryoshka Approach

Purpose—The purpose of this paper is to present a new method for representing heterogeneous materials using nested STL shells, based, in particular, on the density distributions of human bones. Design/methodology/approach—Nested STL shells, called Matryoshka models, are described, based on their namesake Russian nesting dolls. In this approach, polygonal models, such as STL shells, are “stacked” inside one another to represent different material regions. The Matryoshka model addresses the challenge of representing different densities and different types of bone when reverse engineering from medical images. The Matryoshka model is generated via an iterative process of thresholding the Hounsfield Unit (HU) data using computed tomography (CT), thereby delineating regions of progressively increasing bone density. These nested shells can represent regions starting with the medullary (bone marrow) canal, up through and including the outer surface of the bone. Findings—The Matryoshka approach introduced can be used to generate accurate models of heterogeneous materials in an automated fashion, avoiding the challenge of hand-creating an assembly model for input to multi-material additive or subtractive manufacturing. Originality/Value—This paper presents a new method for describing heterogeneous materials: in this case, the density distribution in a human bone. The authors show how the Matryoshka model can be used to plan harvesting locations for creating custom rapid allograft bone implants from donor bone. An implementation of a proposed harvesting method is demonstrated, followed by a case study using subtractive rapid prototyping to harvest a bone implant from a human tibia surrogate

Measuring work disability in the U.S.: conceptual, methodological, and diagnostic considerations

The Work-Disability Functional Assessment Battery (WD-FAB) is a self-reported measure, developed to allow the SSA to collect systematic and comprehensive information about claimants’ functioning. It consists of eight scales: Basic Mobility, Upper Body Function, Fine Motor Function, Community Mobility, Cognition & Communication, Resilience/Sociability, Social Interactions, and Mood & Emotions. Three studies were conducted to evaluate the WD-FAB and apply it as an outcome measure to examine questions relevant to work disability measurement. "Examining Activity Domain Structure of the International Classification of Functioning, Disability, and Health (ICF)" empirically tests the structure of the WHO’s ICF Activity subdomains by comparing it to the empirical structure of the WD-FAB. The comparison found good alignment between the physical function WD-FAB scales and ICF Mobility; several Activity subdomains converge into Cognition & Communication in the WD-FAB. Mental Functions and certain Interpersonal Interactions converge. A re-organization of the subdomains into distinct, measurable constructs is presented for future ICF revisions. "Who Applies to Social Security Disability Programs? Demographic and Functional Differences among Claimants" examines how Social Security disability claimants compare sociodemographically to the working age US population, assesses differences in claimants’ functional status by demographic characteristics, and showcases a method to detect Differential Item Functioning (DIF), which, once controlled for, minimizes measurement error. 17 items displayed DIF, primarily based upon gender. Claimants were sociodemographically different from the general sample and reported lower functioning. Within claimants, there were very few differences of consequence in function between different sociodemographic groups. "Determining Functional Profiles of Common Conditions explores the relationship between diagnoses and function." Common patterns of diagnoses among claimants were identified: musculoskeletal, cancer, multisystem, neurological & sensory, and mental conditions. Many of the diagnosis groups showed unique functional features. The identification of functional profiles for different condition groups suggests that WD-FAB scores may add value to the disability determination process. There is no single litmus test for work disability, but incorporating self-reported experiences is becoming an increasingly common focus in the field. This work demonstrates how a conceptually grounded self-reported measure of functioning can be used to understand the condition of individuals whose health limits their ability to work