1,720,956 research outputs found
Advanced human body modelling to support designing products for physical interaction
No full textWe are using many designed artefacts in our daily life. These artefacts are typically in physical interaction with the human body, and cause stresses and deformations inside the tissues. When these stresses exceed a given level, the proper physiological functioning of the tissues is limited, and ergonomics discomfort or even medical complications can appear. It is important to consider these effects in designing artefacts. However, consideration of these effects is not straightforward, because we need more knowledge about the mechanisms of human-product physical interaction, about the behaviour of the tissues in the contact region, and about the opportunities to influence the interaction in a positive way. There are no means available to directly study the internal effects that appear inside the body of the user when a particular artefact is used. Therefore we have to use a mechanical-physiological model of the human body to generate the information needed for an ergonomically proper designing of artefacts. Apart from the simulation of the internal loads, this model is supposed to be able to model the physiological functioning. In the past several efforts have been made to develop combined anthropometric and mechanical models, that can approximate the behaviour of the human body. However, these models are not able to represent complex biomechanical properties, anthropometric variability, tissue relocation, complex mechanical properties, and physiological functioning of the involved tissues. The goal of this thesis is to explore knowledge, and to evelop and verify conceptual solutions for complex behavioural modelling of various human bodies and parts of it. The research hypothesis was that this goal can be achieved by the development of a knowledge intensive, multi-representational model of the human body, which has been called advanced human body model. This advanced model (i) considers the anthropometric variability of the whole body and its constituents, (ii) is able to compute the effects of the external loads on the internal structures and tissues of the body, (iii) provides information about the deformed shape of the body when it interacts with the used artefact, and (iv) integrates these aspects into one consistent system of knowledge and processing algorithms. In addition to collecting and structuring the knowledge needed for an advanced human body model, algorithms and procedures have been developed. The knowledge structures and the algorithms have been tested and validated in a pilot application. Commercial software tools were used together with newly developed programs to operationalise the advanced human body model. The software tools are able to support the consideration of anthropometric variability, to represent a cluster of shapes of the human body, to generate instances, to represent the mechanical and biophysical properties, to analyse the restructuring and loading of the internal tissues, to determine the physical deformation of the body being in contact with the artefact, and to facilitate using this information in an ergonomically proper designing of the artefact. In our application the artefacts were various sitting supports. The results obtained with the pilot implementation show that (i) useful shape models can be developed based on a small set of descriptive parameters, (ii) the simulation of the material properties based on the generalised Mooney-Rivlin constitutive equations provides no adequate results, and asks for further research, (iii) the current finite element based simulation packages can not sufficiently cope with the complexities of human body modelling, and (iv) advanced human body models open up new opportunities in optimising the shape of products according to ergonomics criteria.Design, Engineering and Productio
Variation in Sitting Pressure Distribution and Location of the Points of Maximum Pressure with Rotation of the Pelvis, Gender and Body Characteristics
No full textThe pressure distribution and the location of the points of maximum pressure, usually below the ischial tuberosities, was measured for subjects sitting on a flat, hard and horizontal support, and varying angle of the rotation of the pelvis. The pressure data were analyzed for force- and pressure-related quantities. Multiple regression was applied to explore relationships between these quantities and (i) a set of body characteristics, and (ii) the pelvis rotation. The maximum pressure and the pressure gradient were mainly explained by the ectomorphic index, and the distance between the maximum pressure points by gender and the angle of rotation of the pelvis.Design EngineeringIndustrial Design Engineerin
Editorial: Special Issue on Virtual Reality and Ergonomics Enablers for Product Development
No full textDesign EngineeringIndustrial Design Engineerin
Multi-dimensional digital human models for ergonomic analysis based on natural data representations
Get PDFDigital human models are often used for ergonomic analysis of product designs, before physical prototypes are available. However, existing digital human models cannot be used to simultaneously: 1) consider the tissue loads and the physiological effects of the tissue loads; 2) optimise the product properties. This paper develops multi-dimensional digital human models for ergonomic analysis based on natural data representations, which include anatomy, morphology, behaviour, physiology, tissue, and posture data representations. The results show that the multi-dimensional digital human models can be used to: 1) accelerate the design process; 2) assess mechanical and physiological loads inside the body and in the contact area between the body and the product; 3) optimise the quality of the product; 4) reduce the number of user trials needed to create the product.Design EngineeringIndustrial Design Engineerin
Reflections on delivering a cross-discipline, cross-cultural, international, masters-level collaborative course using e-Learning technologies
No full textThis paper presents a case study on the experience of delivering an Internet-based international collaborative semester course at intermediate postgraduate level and attempts to distill a model for exploring the success factors involved when presenting such courses. The pedagogic and practical implications in terms of the effectiveness of the technological and system administrative choices made for delivering the course content and facilitating team interaction is evaluated. The structure and contents of the course are considered in light of the focus on innovation within the development of novel ubiquitous products and services. Furthermore the synchronous nature of the real time collaboration tools employed are contrasted with asynchronous alternatives given that the participating countries are highly distributed according to longitude and diverse according to their native language, cultural customs and technical skill set. A survey of extant technologies employable in facilitating such courses is presented together with an analysis of the criteria necessary to facilitate a successful delivery of the course. The institutional needs of security and management of its ICS resources are placed in the context of the effective administration of such a course given the highly heterogeneous selection of technologies employed. The contrast of the available resources of the only first world participant, functioning also as the virtual host (the Netherlands), with the remainder of the consortium is made in terms of technological and communication constraints. The problem is then modelled as a multi-agent collaborative communication problem in which participants are represented by proxy agents within a virtual environment. Multi-agency is selected as a framework for analysing the problem domain due to its strong theoretical underpinnings in computer science, economics and other fields. Each agent attempts to maximise its own utility function value based on its ability to solve sub-tasks assigned to it coupled with their contribution to the global utility for the agent’s team. Communication channels exists between agents, vary in terms of their availability over time and are not uniformly distributed between agents. Furthermore such channels may be classed as either synchronous or asynchronous. Likewise in order to model the cross-disciplinary nature of the course each task requires certain competencies to be completed effectively, these competencies are not uniformly distributed amongst the agents. To model differences in time zones each agent's cognitive capacity also varies according to a time based function and point of origin. This model is formalised using standard software engineering modelling languages and salient aspects implemented using standard agent oriented development frameworks. Although the system models a collaboration the reality of such interactions are that agents are inherently self-interested. Due to this, the model allows for differing task allocation strategies to be employed and the emergent effects of policies such as egalitarian, meritocratic and historical performance based distribution schemes to be compared. The end result of this modelling activity is to establish the most favourable mix of communication channels which would need to be provided for a given globally distributed team composition. The model may also be used to explore the most favourable policy-mix from an institution's point of view in order to facilitate such collaborations while maintaining an adequate level of security.Design EngineeringIndustrial Design Engineerin
Development of design competences for international team-based cyber physical systems
No full textDesign EngineeringIndustrial Design Engineerin
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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