Visualization methods for analysis of 3D multi-scale medical data

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Humanoid Robots

For many years, the human being has been trying, in all ways, to recreate the complex mechanisms that form the human body. Such task is extremely complicated and the results are not totally satisfactory. However, with increasing technological advances based on theoretical and experimental researches, man gets, in a way, to copy or to imitate some systems of the human body. These researches not only intended to create humanoid robots, great part of them constituting autonomous systems, but also, in some way, to offer a higher knowledge of the systems that form the human body, objectifying possible applications in the technology of rehabilitation of human beings, gathering in a whole studies related not only to Robotics, but also to Biomechanics, Biomimmetics, Cybernetics, among other areas. This book presents a series of researches inspired by this ideal, carried through by various researchers worldwide, looking for to analyze and to discuss diverse subjects related to humanoid robots. The presented contributions explore aspects about robotic hands, learning, language, vision and locomotion

Fluid Dynamics of Biomimetic Pectoral Fin Propulsion Using Immersed Boundary Method

Numerical simulations are carried out to study the fluid dynamics of a complex-shaped low-aspect-ratio pectoral fin that performs the labriform swimming. Simulations of flow around the fin are achieved by a developed immersed boundary (IB) method, in which we have proposed an efficient local flow reconstruction algorithm with enough robustness and a new numerical strategy with excellent adaptability to deal with complex moving boundaries involved in bionic flow simulations. The prescribed fin kinematics in each period consists of the power stroke and the recovery stroke, and the simulations indicate that the former is mainly used to provide the thrust while the latter is mainly used to provide the lift. The fin wake is dominated by a three-dimensional dual-ring vortex wake structure where the partial power-stroke vortex ring is linked to the recovery-stroke ring vertically. Moreover, the connection of force production with the fin kinematics and vortex dynamics is discussed in detail to explore the propulsion mechanism. We also conduct a parametric study to understand how the vortex topology and hydrodynamic characteristics change with key parameters. The results show that there is an optimal phase angle and Strouhal number for this complicated fin. Furthermore, the implications for the design of a bioinspired pectoral fin are discussed based on the quantitative hydrodynamic analysis

Haptics Rendering and Applications

There has been significant progress in haptic technologies but the incorporation of haptics into virtual environments is still in its infancy. A wide range of the new society's human activities including communication, education, art, entertainment, commerce and science would forever change if we learned how to capture, manipulate and reproduce haptic sensory stimuli that are nearly indistinguishable from reality. For the field to move forward, many commercial and technological barriers need to be overcome. By rendering how objects feel through haptic technology, we communicate information that might reflect a desire to speak a physically- based language that has never been explored before. Due to constant improvement in haptics technology and increasing levels of research into and development of haptics-related algorithms, protocols and devices, there is a belief that haptics technology has a promising future

Manoeuvreergedrag van containerschepen in slibrijke vaarwateren Manoeuvring Behaviour of Container Vessels in Muddy Navigation Areas

English version below *** Vele havens en toegangsgeulen hebben te lijden onder de vorming van sliblagen op de bodem van de vaargeul. Om de toegang te garanderen zijn onderhoudsbaggerwerken noodzakelijk. Nu is de vraag welke vaardiepte nodig is voor een veilige scheepvaart. In het geval van sliblagen is de grens tussen water en bodem niet erg duidelijk, en wordt vaak het concept nautische bodem gebruikt. Dit is de positie waar de karakteristieken van de sliblaag een kritische limiet bereiken. Wanneer de kiel van het schip met deze limiet in aanraking komt dan ontstaat er schade of is het schip niet langer manoeuvreerbaar. Door toepassing van dit concept kan men toelaten dat de scheepskiel in contact komt met de bovenste sliblagen, op voorwaarde dat het schip nog onder controle kan gehouden worden. Om het gedrag van de manoeuvreerbaarheid te beoordelen werd een uitgebreid programma modelproeven uitgevoerd in de sleeptank , waarbij het gedrag van het schip boven en in een serie kunstsliblagen werd beproefd. Aan de hand van de meetgegevens werd eerst een wiskundig model opgesteld dat toelaat om per combinatie van kielspeling en sliblaagconditie het manoeuvreergedrag na te bootsen in een scheepsmanoeuvreersimulator. Vervolgens werd een veralgemeend wiskundig model opgesteld dat rekening houdt met kielspeling en sliblaagkarakteristieken en zo toelaat om het gedrag van eender welk diepstekend containerschip in realistische slibrijke vaarwateren te voorspellen. Als praktische toepassing werden de theoretische ontwikkelingen gebruikt voor het bepalen van een optimale nautische bodem en operationele grenzen voor de doorvaarbaarheid van het slib in de haven van Zeebrugge, wat heeft geleid tot efficiëntere onderhoudsbaggerwerken en de toelating van grotere containerschepen. *** Many harbours and access channels suffer from the formation of mud layers on the bottom. Maintenance dredging works are necessary to guarantee the accessibility. The question is which navigation depth guarantees a safe shipping traffic. In case of mud layers the border between water and bottom is not unambiguous. Therefore the nautical bottom concept is used. This is the position where the characteristics of the bottom reach a critical limit. If the ship’s keel touches this limit damage occurs or the ship cannot longer be controlled. The implementation of the nautical bottom concept allows the ship to penetrate the upper mud layers if at least the ship can be controlled. To assess the manoeuvrability a comprehensive experimental program has been carried out in the Towing Tank for Manoeuvres in Shallow Water – collaboration Flanders Hydraulics Research – Ghent University in Antwerp. During this program the ship’s behaviour has been measured above and in contact with a series of artificial mud layers. Based on the measurements a mathematical model was built which allows to simulate the manoeuvring behaviour for each combination of bottom condition and under keel clearance on a ship manoeuvring simulator. Subsequently a consolidated mathematical model has been built, which takes into account the under keel clearance and mud characteristics. This model allows to predict the manoeuvrability of any deep drafted container vessel in fairways with any realistic mud layer. An example of application was the determination of the nautical bottom and operational limits for the penetrability of the mud in the harbour of Zeebrugge. This lead to a more efficient maintenance dredging and the admission of larger container vessels

Proceedings of the 95th Annual Virginia Academy of Science Meeting, 2017

Full proceedings of the 95th Annual Virginia Academy of Science Meeting, May 17-19, 2017, at Virginia Commonwealth University, Richmond, VA

Примена виртуелних светова у истраживању теорије агената и инжењерском образовању

The focus of this doctoral dissertation is on exploring the potentials of virtual worlds, for applications in research and education. Regarding this, there are two central aspects that are explored in the dissertation. The first one considers the concept of autonomous agents, and agent theory in general, in the context of virtual worlds. The second aspect is related to the educational applications of virtual worlds, while especially focusing on the concept of virtual laboratories. An introduction to basic terminology related to the subject is given at the start of the dissertation. After that, a thorough analysis of the role of agents in virtual worlds is presented. This, among others, includes the analysis of the techniques that shape the agent’s behavior. The development of the virtual gamified educational system, specially dedicated to agents is then presented in the dissertation, along with a thorough description. While, in the end, analysis of the concept of virtual laboratories in STE (Science, Technology, and Engineering) disciplines is performed, and existing solutions are evaluated according to the criteria defined in the dissertation.Фокус ове докторске дисертације је на истраживању потенцијала виртуелних светова за примене у истраживањима и образовању. У вези са тим, постоје два главна аспекта која су обрађена у дисертацији. Први аспект се тиче концепта аутономних агената, као и теорије агената у целини, а у контексту виртуелних светова. Други аспект је везан за примену виртуелних светова у образовању, при чему је посебан акценат стављен на виртуелне лабораторије. На почетку дисертације је дат кратак увод који се тиче терминологије и појединих појмова везаних за област којом се ова дисертција бави. Након тога је представљена систематична и темељна анализа улоге агената у виртуелним световима. Између осталог, ово укључује и анализу техника потребних за обликовање понашања агената. Потом је у дисертацији детаљно представљен развој оригиналног виртуелног образовног система посвећеног агентима. На крају, анализиран је концепт виртуелних лабораторија у НТИ (наука, технологија, инжењерство) дисциплинама и извршена је евалуација постојећих решења у складу са критеријумима који су дефинисани у дисертацији

A biomechanics-based articulation model for medical applications

Computer Graphics came into the medical world especially after the arrival of 3D medical imaging. Computer Graphics techniques are already integrated in the diagnosis procedure by means of the visual tridimensional analysis of computer tomography, magnetic resonance and even ultrasound data. The representations they provide, nevertheless, are static pictures of the patients' body, lacking in functional information. We believe that the next step in computer assisted diagnosis and surgery planning depends on the development of functional 3D models of human body. It is in this context that we propose a model of articulations based on biomechanics. Such model is able to simulate the joint functionality in order to allow for a number of medical applications. It was developed focusing on the following requirements: it must be at the same time simple enough to be implemented on computer, and realistic enough to allow for medical applications; it must be visual in order for applications to be able to explore the joint in a 3D simulation environment. Then, we propose to combine kinematical motion for the parts that can be considered as rigid, such as bones, and physical simulation of the soft tissues. We also deal with the interaction between the different elements of the joint, and for that we propose a specific contact management model. Our kinematical skeleton is based on anatomy. Special considerations have been taken to include anatomical features like axis displacements, range of motion control, and joints coupling. Once a 3D model of the skeleton is built, it can be simulated by data coming from motion capture or can be specified by a specialist, a clinician for instance. Our deformation model is an extension of the classical mass-spring systems. A spherical volume is considered around mass points, and mechanical properties of real materials can be used to parameterize the model. Viscoelasticity, anisotropy and non-linearity of the tissues are simulated. We particularly proposed a method to configure the mass-spring matrix such that the objects behave according to a predefined Young's modulus. A contact management model is also proposed to deal with the geometric interactions between the elements inside the joint. After having tested several approaches, we proposed a new method for collision detection which measures in constant time the signed distance to the closest point for each point of two meshes subject to collide. We also proposed a method for collision response which acts directly on the surfaces geometry, in a way that the physical behavior relies on the propagation of reaction forces produced inside the tissue. Finally, we proposed a 3D model of a joint combining the three elements: anatomical skeleton motion, biomechanical soft tissues deformation, and contact management. On the top of that we built a virtual hip joint and implemented a set of medical applications prototypes. Such applications allow for assessment of stress distribution on the articular surfaces, range of motion estimation based on ligament constraint, ligament elasticity estimation from clinically measured range of motion, and pre- and post-operative evaluation of stress distribution. Although our model provides physicians with a number of useful variables for diagnosis and surgery planning, it should be improved for effective clinical use. Validation has been done partially. However, a global clinical validation is necessary. Patient specific data are still difficult to obtain, especially individualized mechanical properties of tissues. The characterization of material properties in our soft tissues model can also be improved by including control over the shear modulus