Catálogo de publicaciones - libros

The 3D scans of human bodies contain over hundreds of thousand grid points. To be used effectively for analysis, indexing, searching, clustering and retrieval, these human bodies requires a compact shape representation. We have developed compact representations based on human body shape based on lengths mostly between joints of single large bones and in the second method silhouettes of the human body are created and then encoded as Fourier shape descriptors. We also have developed two such compact representations based on human head shape by applying Principal Component Analysis on the facial surface and in the second method the whole head is transformed to a spherical coordinate system expanded in a basis of Spherical Harmonics.

The objective of this paper is to find an appropriate method to realize the simulation of hand grasping motion for astronauts training. In this paper, on the basis of analysis and comparison of a variety of methods of hand grasping motion, we come up with an idea combined interpolation and inverse kinematics for hand motion simulation. An example demonstrates the method’s effectiveness and practicability.

The paper discusses the complexity involved in considering targeted product users’ anthropometric variation in multivariate design problems, such as the design of workplaces or vehicle interiors. The authors argue for the advantages of offering designers a number of predefined digital human models to incorporate in the CAD product models. A study has been carried out in order to illustrate the use of predefined digital human models in vehicle interior design by using the Digital Human Modelling (DHM) tool RAMSIS. The paper takes a designer’s view of digital human modelling and illustrates how DHM can be of great value in the design process, but also considers what implications this has on the functionality and usability of DHM tools.

The research presented here makes a contribution to the understanding of the recognition of biological motion by comparing human recognition of a set of everyday gestures and motions with machine interpretation of the same dataset. Our reasoning is that analysis of any differences and/or correlations between the two could reveal insights into how humans themselves perceive motion and hint at the most important cues that artificial classifiers should be using to perform such a task. We captured biological motion data from human participants engaged in a number of everyday activities, such as walking, running and waving, and then built two artificial classifiers (a Finite State Machine and a multi-layer perceptron artificial neural network, ANN) which were capable of discriminating between activities. We then compared the accuracy of these classifiers with the abilities of a group of human observers to interpret the same activities when they were presented as moving light displays (MLDs). Our results suggest that machine recognition with ANNs is not only comparable to human levels of recognition but can exceed it in some instances.

In order to adapt for a high-rate transmission and improve the performance of operation, in this paper, a new low complex sphere decoding (SD) algorithm is proposed in the MIMO-ZP-OFDM systems. It is an approximate optimization algorithm and can be used in the space-time coding and uncoded multiple-antenna systems. ML sequence detection compared with SD algorithm the latter can reduce the complex and keep the performance of systems, especial for high-rate transmission operation and the occasion of transmit antenna beyond receive antenna. Simulation results show that the efficiency and superiority of this algorithm.

In this paper, the human musculoskeletal model based on the medical images of the Korean standard male and the computer graphics based simulation technology with biomechanical analyses are presented. The virtual human model consists of three components. The model component includes the development of anatomically accurate geometric models with physiologically relevant material data. The analysis component includes various types of mechanical. In the simulation component, task-oriented graphic simulation would be performed for virtual evaluation, test, measurement, design, and planning. Three biomechanical analyses with graphic simulation using the virtual Korean model were performed; the surgical simulation of bone fracture surgery, the biomechanical evaluation of surgical implant in knee, and the graphic visualization and simulation of tennis play. In conclusion, the developed virtual Korean model of the musculoskeletal system would have lots of potentiality for biomechanical research and development in various fields, such as medical industry, automobile, ergonomics, or nuclear industry.

It is not well understood whether strength could ever influence performance in which only sub-maximal, moderate exertions are needed although strength may be indicative of the movement performance at or near the maximal level. In this paper, we present some evidence from two studies suggesting the strength effects on performance strategies in volitional physical tasks, and based on the evidence, a new framework was proposed for human movement modeling and simulation that incorporates the strength factor.

Human phonation does not merely depend upon the vibration of the vocal folds. The false vocal fold (FVF), as an important laryngeal constriction, has also been found by more and more research both in clinically and computer simulations that it plays an important role during phonation and contributes significantly to the aerodynamics and sound generation processes of human voice production. Among many parameters which are used to determine and describe the geometry of the false vocal folds, the false vocal fold gap (GFVF), which means the minimal distance between the two false vocal folds, is regarded as an important and dominant parameter. Therefore, this study explores the effects of the FVF gaps on the intralaryngeal pressure distributions, laryngeal resistance and flows using both three-dimensional Plexiglas model and commercially available computational fluid dynamics code.

Three glottal angles, divergent 40°, uniform 0°, and convergent -40°were used for this study to explore the effects of FVF gaps, as they represent the basic glottal shapes typically expected in phonation, the angle values also were typically expected for most phonation in modal Register. A wide variety of FVF gaps (GFVF) were parameterized with 12 different values: 0.02, 0.04, 0.06, 0.08, 0.09, 0.1, 0.11, 0.12, 0.16, 0.2, 0.4, 0.6 cm to represent important geometries often appearing within phonatory vibratory cycles. These gaps were used for each glottal angle. The specific design of the FVFs followed prior literature. The minimal glottal diameter (Dg) was constantly at 0.06 cm in this study for each FVF gaps, and the translaryngeal pressure were held constant at 8 cm H2O. A nonvibrating laryngeal airway Plexiglas model, which had linear dimensions 1.732 times of a normal male larynx, was used in this study. In order to measure pressures inside the Plexiglas model, twelve cylindrical ducts were made on the midline of the laryngeal wall of the model. The diameter of each duct was 0.07 cm human size (0.12 cm in the model), so that the connector of an Entran EPE-551 pressure transducer could fit snugly into the holes. The distance between the centers of each hole was 0.14 cm human size. FLUENT (Fluent, Inc., Lebanon, NH), a commercially available computational fluid dynamics code was also used to obtain estimates of the normal wall pressures along the laryngeal surfaces (including the surfaces of vocal folds, ventricles, and false vocal folds) as a function of the FVF gaps and the glottal angles. The code is based on the control-volume technique and was used to solve the Navier-Stokes equations for constant shapes (not for vibrating vocal folds), laminar, incompressible airflow physics occurring inside the symmetric laryngeal geometries. The flow field was assumed to be symmetric across the midline of the glottis in this study, and therefore only the half flow field was modeled.

The results suggest that (1) the intralaryngeal pressure was lowest and the flow was highest (least flow resistance) when the FVF gap was 1.5-2 times of Dg, the intralaryngeal pressures decreased and flows increased as smaller FVF gaps increased, and the intralaryngeal pressures increased and flows decreased as larger FVF gaps increased, indicating that the least pressure drop for any given flow (that is, the least flow resistance) was found to correspond to the 1.5-2 times of Dg for different glottal angle. Suggesting that the 1.5-2 times of Dg might be the optimal gap for pressure, and efficient phonation may involve laryngeal shaping of this condition. Therefore, the positioning and existing structure of the FVFs can aid in phonation by reducing energy losses and increasing airflow in the larynx when positioned appropriately; (2) both the pressure and flow were unaffected when the FVF gaps larger than 0.4 cm; (3) the divergent glottal angle gave lower pressure and greater flow than the convergent and uniform glottal angle as no FVF conditions; (4) the present of the FVF decreased the effects of the glottal angle on both the intralaryngeal pressure and flow to some extent, and the smaller the FVF gaps, the smaller this effect. Perhaps more important, (5) the present of the FVF also moving the separation points downstream, straitening the glottal jet for a longer distance, decreasing overall laryngeal resistance, and reducing the energy dissipation, suggesting that the FVF would be of importance to efficient voice production; (6) the empirical pressure distributions were supported by computational results. The results suggest that the intralaryngeal pressure distributions and the laryngeal flow resistance are highly affected by the presence of the FVFs, and the FVFs can aid in phonation when by reducing energy losses positioned appropriately. Therefore, the results might be helpful not only in maintaining healthy vocal habits, but also in exploring surgical and rehabilitative intervention of related voice problem. The results also suggest that they may be incorporated in the phonatory models (physical or computational) for better understanding of vocal mechanics.

A recent study [2] proposed a forward bio-dynamic model of multi-fingered hand movement. The model employed a physics-based heuristic algorithm for system identification of the model parameters, and succeeded in replicating measured multi-fingered flexion-extension movement. However, while the model itself is general and readily applicable to other bodily movements, the heuristic algorithm required empirical adjustments to initial setups, and was therefore difficult to generalize. This paper introduces a rigorous and more robust parameter estimation algorithm to enhance the intended general modeling approach for digital human movement simulation. The algorithm is demonstrated by solving the same modeling problem posed in [2].

Form comparison is a fundamental part of many anthropometric, biological, anthropological, archaeological and botanical researches, etc. In traditional anthropometric form comparison methods, geometry characteristics and internal structure of surface points are not adequately considered. Form comparison of 3D anthropometric data can make up the deficiency of traditional methods. In this paper, methods for analyzing 3D other than 2D objects are highlighted. We summarize the advance of form comparison techniques in the last decades. According to whether they are based upon anatomical landmarks, we partition them into two main categories, landmark-based methods and landmark-free methods. The former methods are further sub-divided into deformation methods, superimposition methods, and methods based on linear distances, while the latter methods are sub-divided into shape statistics-based methods, methods based on function analysis, view-based methods, topology-based methods, and hybrid methods. Examples for each method are presented. The discussion about their advantages and disadvantages are also introduced.