bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel technique for visualization of the normal and cleft fetal secondary palate: angled insonation and three‐dimensional ultrasound
Authors: Pilu G. , Segata M. 
Published: November 2006

AbstractObjectiveTo evaluate the effectiveness of a novel approach to the visualization of the fetal secondary palate using three‐dimensional (3D) ultrasound.MethodsSonographic examinations were performed in normal fetuses and in one fetus with cleft lip and palate. To avoid acoustic shadowing from the alveolar ridge, the secondary palate was insonated at a 45° angle in the sagittal plane, and 3D ultrasound was used to reconstruct axial and coronal planes.ResultsThe secondary palate was successfully visualized in 10 of 15 normal fetuses, both in the axial and coronal planes. In the fetus with cleft lip and palate the lesion of the secondary palate was clearly demonstrated, particularly in the coronal plane.ConclusionAngled insonation and 3D ultrasound allow clear visualization of normal and cleft secondary palate. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Motor planning: An architecture for specifying and controlling the behaviour of virtual actors
Authors: Zeltzer David , Johnson Michael B. 
Published: November 2006

AbstractAs virtual worlds become increasingly complex,task levelinteraction with virtual actors becomes correspondingly important. The control problem simply becomes unmanageable if we try to interact with synthetic agents at the wrong level of abstraction. However, it is not sufficient merely to implement a set of behaviours for a virtual actor; we require some mechanism for selecting and sequencing motor skills appropriate to the current behavioural goalsandthe states of other objects and actors in the virtual environment. In this paper we will describe a mechanism for linkingperceptionandactionto generate routine behaviours in a process we callmotor planning.We present our implementation of the skill network, in which motor skills are the nodes and the arcs represent inhibitory and excitatory connections, including extensions to this architecture based on recent work in robotics. We characterize the domain of motor planning, i.e. what kinds of behaviour can it account for, and when will it fail? We close with a discussion of the limits of our current implementation and work that remains to be done.
Inverse lagrangian dynamics for animating articulated models
Authors: Vasilonikolidakis Nickos , Clapworthy Gordon J. 
Published: November 2006

AbstractThis paper presents the application of inverse Lagrangian dynamics for the purpose of animating articulated models. The method orginates from mechanics and robotics and has been adapted to deal with branched kinematic chains and joints with multiple degrees of freedom. The method is then reformulated to calculate the ground reaction forces that apply to the body. The approach is direct and does not involve guesswork. The formulation has been implemented into a general animation system that is entirely interactive and supports the facility of simulating generic articulated models.
Automated lip‐sync: Background and techniques
Authors: Lewis John 
Published: November 2006

AbstractThe problem of creating mouth animation synchronized to recorded speech is discussed. Review of a model of speech sound generation indicates that the automatic derivation of mouth movement from a speech soundtrack is a tractable problem. Several automatic lip‐sync techniques are compared, and one method is described in detail. In this method a common speech synthesis method, linear prediction, is adapted to provide simple and accurate phoneme recognition. The recognized phonemes are associated with mouth positions to provide keyframes for computer animation of speech. Experience with this technique indicates that automatic lip‐sync can produce useful results.
Simulating the structure and dynamics of human hair: Modelling, rendering and animation
Authors: Rosenblum Robert E. , Carlson Wayne E. , Tripp Edwin 
Published: November 2006

AbstractWe develop and present a new approach to modelling the characteristics of human hair, considering not only its structure, but also the control of its motion and a technique for rendering it in a realistic form. The approach includes a system for interactively defining the global positioning of the strands of hair on the head. Special attention is paid to the self shadowing of the hair. A mass/spring/hinge system is used to control a single strand's position and orientation. We demonstrate that this approach results in a believable rendition of the hair and its dynamics.
Graphical displays of human strength data
Authors: Wei Susanna , Badler Norman I. 
Published: November 2006

AbstractTo facilitate the effective use of strength data in a human‐task simulation environment, we have developed graphical methods to display the multidimensional characteristics of strength data. We use human figures together with two and three dimensional graphical symbols, colours and animations to visualize the effects of different parameters on strength. These displays give a dynamic view of the effects of various parameters on strength, and illustrate safe and forbidden body postures (or regions) in terms of strength capabilities.
The virtual museum: Interactive 3D navigation of a multimedia database
Authors: Miller Gavin , Hoffert Eric , Chen Shenchang Eric , Patterson Elizabeth , Blackketter Dean , Rubin Steve , Applin Sally Ann , Yim Derrick , Hanan Jim 
Published: November 2006

AbstractThe Virtual Museum is an interactive, electronic museum where users can move from room to room, and select any exhibit in a room for more detailed examination. The exhibits in the museum are educational, encompassing topics such as medicine, plant growth, the environment, and space. To facilitate interaction with the museum, a new method for navigating through a prerendered 3D space, and interacting with objects in that space has been developed, called ‘virtual navigation’. Virtual navigation employs real‐time video decompression for the display of, and interaction with, high‐quality computer animation. In addition, a representation for 3D objects in animated sequences is used which permits pixel‐accurate, frame‐accurate object picking, so that a viewer can select any 3D object to trigger movement within the 3D space, to examine an exhibit in animated form, or to play a digital movie or soundtrack. The use of precomputed video permits 3D navigation in a realistic‐looking space, without requiring special‐purpose graphics hardware.
Computer animated visual translation from natural language to sign language
Authors: Lee Jintae , Kunii Tosiyasu L. 
Published: November 2006

AbstractComputer animation and visualization can facilitate communication between the hearing impaired and those with normal speaking capabilities. This paper presents a model of a system that is capable of translating text from a natural language into animated sign language. Techniques have been developed to analyse language and transform it into sign language in a systematic way. A hand motion coding method as applied to the hand motion representation, and control has also been investigated. Two translation examples are also given to demonstrate the practicality of the system.
Physical simulation of land vehicles with obstacle avoidance and various terrain interactions
Authors: Jimenez Stéphane , Luciani Annie , Raoult Olivier 
Published: November 2006

AbstractProgramming the motions of an autonomous planetary robot moving in an hostile and hazardous environment is a complex task which requires both the construction of nominal motion plans and the anticipation as far as possible of the effects of the interactions existing between the vehicle and the terrain. In this paper we show how physical models and dynamic simulation tools can be used for amending and completing a nominal motion plan provided by a classical geometrical path planner. The purpose of our physical modeller‐simulator is to anticipate the dynamic behaviour of the vehicle while executing the nominal motion plan. Then the obtained simulation results can be used to assess and optimize the nominal motion plan. In the first part, we outline the physical models that have been used for modelling the different types of vehicle, of terrain and of vehicle‐surface interactions. Then we formulate the motion planning problem through the definition of two basic abstract constructions derived from physical model: the concept of generalized obstacle and the concept of physical target. We show with various examples how it is possible, when using this method, to solve the locomotion problem and the obstacle avoidance problem simultaneously and, furthermore, to provide the human operator with a true force feedback gestural control over the simulated robot.
Programming mechanical simulations
Authors: Kearney Joseph K. , Hansen Stuart , Cremer James F. 
Published: November 2006

AbstractThis paper examines the control of complex physical objects in simulation. We introduce a programming paradigm that allows a simulation to be treated as a multi‐level constraint solver. The control programmer is given the ability to specify constraints on the controlled response of mechanisms and to conditionally change these constraints dependent on the state of system. The approach facilitates the development of model‐based, event‐driven control programs. The usefulness of the paradigm is demonstrated through the simulation of a hopping robot.
Computation of global illumination in a participating medium by monte carlo simulation
Authors: Pattanaik S. N. , Mudur S. P. 
Published: November 2006

AbstractThis paper discusses techniques for the computation of global illumination in environments with a participating medium using a Monte Carlo simulation of the particle model of light. Efficient algorithms and data structures for tracking the particles inside the volume have been developed. The necessary equation for computing the illumination along any given direction has been derived for rendering a scene with a participating medium. A major issue in any Monte Carlo simulation is the uncertainty in the final simulation results. Various steps of the algorithm have been analysed to identify major sources of uncertainty. To reduce the uncertainty, suitable modifications to the simulation algorithm have been suggested using variance reduction methods of forced collision, absorption suppression and particle divergence. Some sample scenes showing the results of applying these methods are also included.
Animation through space and time based on a space deformation model
Authors: Bechmann Dominique , Dubreuil Nicolas 
Published: November 2006

AbstractTo animate deformable objects through time and space, a new technique that will be referred to as DOGMA is proposed here. It is well suited to animation for both interactive design and real‐time visualization.The concept of animation primitives based on an extension to animation of the space deformation model is introduced. Animation primitives can be added to any geometrical modeller because they are independent of the underlying geometrical model of the animated objects. It encapsulates animation through space and time under a unique formalism. A local control of deformations both through space and time is easily specified. A direct manipulation of objects is provided. At any time, animated objects are continuously computed from their corresponding animation primitives. This dispenses with the necessity for major storage of the interpolation process. A fully interactive system offers an interactive environment which enables the user to animate deformable objects in real time.
Illusion—creating a mock reality
Authors: Stöβer Achim , Leister Wolfgang , Meyer Frerk 
Published: November 2006

AbstractPhotorealistic computer animation sequences have become more important in recent years in visualization and presentation techniques as well as in fine arts. Some aspects of creating a photorealistic computer animation are demonstrated by the following example of the film Illusion that was created by the computer graphics team at the University of Karlsruhe. An overview of modelling methods, some special effects and details on how to administrate a large computer animation project are presented.
A language for the classification and shading of multivariate volume data
Authors: Palmer Thomas C. , Simpson Edward V. , Smith William M. 
Published: November 2006

AbstractA novel, language‐based interface to the specification of multivariate volume classification and shading algorithms has been implemented. The system facilitates experimentation by providing access to data relevant to volume classification and shading (scalars, gradients, and gradient magnitudes) in a C‐like language environment. The user writes code to calculate opacity and colour on a per voxel basis. The code is interpreted and compiled in a transparent fashion and then executed on a volume data‐set. The output is a volume primitive suitable for input to standard volume rendering algorithms.
Design and animation of volume density functions
Authors: Ebert David S. 
Published: November 2006

AbstractThis paper describes the design and animation of volume density functions for creating images containing gases, solid textures and hypertextures. The development of functions for producing images and animations of gases is explained in detail. Procedures for modelling the geometry of various gases are described. Next, animation techniques for volume density functions are described and examples of the animation of these functions are presented, including steam rising from a teacup, wind effects, marble forming, and gas and liquid flow into an opening in a wall. Solid spaces are introduced as a unifying approach to describing and animating object attributes.
A simple approximation to rigid body dynamics for computer animation
Authors: Van Overveld C. W. A. M. 
Published: November 2006

AbstractRecently, the dynamics of linked articulated rigid bodies has become a valuable tool for making realistic three‐dimensional computer animations. An exact treatment of rigid body dynamics, however, is based on rather non‐intuitive results from classical mechanics (e.g. the Euler equations for rotating bodies) and it relies heavily on sophisticated numerical schemes to solve (large) sets of coupled non‐linear algebraic and differential equations. As a result, articulated rigid bodies are not yet supported by most real‐time animation systems. This paper discusses an approach to rigid body dynamics which is based on (both conceptually and algorithmically much simpler) point mechanics; this gives rise to an asymptotically exact numerical scheme (NSI) which is useful in the context of real‐time animation, provided that the number of degrees of freedom of the simulated system is not too large. Based on NSI, a second scheme (NS2) is derived which is useful for approximating the motions of linked articulated rigid bodies; NS2 turns out to be sufficiently fast to give at least qualitative results in real‐time simulation. In general, the algorithm NS2 is not necessarily (asymptotically) exact, but a quantitative analysis shows that in the absence of reaction forces it conserves angular momentum.
Back‐face culling applied to collision detection of polyhedra
Authors: Vaněkčkek George 
Published: November 2006

AbstractBack‐face culling is a preprocessing technique used in computer graphics to speed up the rendering of polyhedra. In this paper we show how this technique can be modified to reduce unnecessary checking of boundary elements in collison detection for a physical‐based simulation and animation systems. At each time step, we determinea prioriwhich faces cannot be part of the contact between two polyhedra and thus can be culled. In the computer graphics technique, the normal vector of a polygon is compared with the view direction. Here, the normal is compared to one or possibly several relative‐velocity vectors, and the face is culled when its motion is in the opposite direction of the normal vector.We also give an algorithm that takes linear time in terms of the number of faces, and on the average eliminates half of the polygons. Owing to its low computational overhead, when it is used as a front end to a collision detection system, a noticeable improvement in performance can be achieved.
An articulated limb motion planner for optimized movement
Authors: Miller David P. , Parent Richard E. 
Published: November 2006

AbstractTask level animation of articulated figures, such as the human body, requires the ability to generate collision‐free goal‐directed motion of individual limbs in the presence of obstacles. This paper describes a new articulated limb motion planner for goal‐directed point‐to‐point reaching motions. The produced motion avoids obstacles while optimizing an objective function.This two‐phase algorithm uses heuristic guided Monte Carlo techniques to create a consistent underlying paradigm. The first phase consists of an existing potential field based random path planner which generates a population of candidate paths. This initial population is fed into the second phase, a genetic algorithm, which iteratively refines the population as it optimizes with respect to the objective function. The refinement process works on the principle ofpath coherency, the idea that a family of closely related collision‐free paths lies in the vicinity of a given collision‐free path.This paper focuses on seven different optimization functions. Optimized trajectories produced by the new motion planner are compared to those generated solely by the random path planner. The presented algorithm is flexible in that a wide range of objective functions can be optimized. Applications of the algorithm include task level animation, ergonomics and robotics.
Object‐oriented motion abstraction
Authors: Erkan Bi̇ilge , Oüzüç Bülent 
Published: November 2006

AbstractAn important problem in the production of an animation sequence is the great amount of information necessary to control and specify the motion. Specification of complex animation sequences with a smaller amount of information is possible if they are built over some abstracted sequences. Abstraction supports dealing with complexity by structuring, so that the necessary features are made available while those that are not necessary are hidden. In our work, motion abstraction is used to build complex animation sequences with the help of object‐oriented concepts. A parametric key‐frame interpolation method is used for producing the in‐between frames of an animation sequence. The parameters that define the motion of a model, in our work, are position, orientation, size, shape and colour. Orientation transformations are implemented by unit quaternions.
A dynamic wrinkle model in facial animation and skin ageing
Authors: Wu Yin , Thalmann Nadia Magnenat , Thalmann Daniel 
Published: November 2006

AbstractThis paper describes a dynamic model to simulate expressive wrinkles in 3D facial animation and skin ageing. A skin surface is defined that can slide over an underlying layer, which constrains the surface by a spring force that simulates the connective fat tissue between them. Muscle masks are constructed to characterize the muscular contractions that provide the facial movement. Skin deformation is simulated through an elastic process assembled with visco and plastic units. By adjusting parameters for this physically based model, distinctive wrinkles for different faces can be generated.
Chemical and physical properties of isomeric glyceryl monoethers
Authors: Wood Randall , Snyder Fred 
Published: November 2006

AbstractLong‐chain saturated and mono‐ and diunsaturated 1‐ and 2‐glyceryl monoethers were synthesized by reacting 1,2‐isopropylidene and 1.3‐benzylidene glycerol potassium salts with alkyl halides in the preparation of the saturated monoethers, and with alkenyl‐p‐toluenesulfonates in the preparation of the unsaturated monoethers, followed by hydrolysis of the blocking groups with boric acid. The progress of the reaction was monitored by gasliquid chromatography (GLC) of the reaction mixture. The 2‐glyceryl ethers, with two exceptions, had not been prepared previously. Normal propyl and 3‐pentyl octadecyl ethers also were synthesized to aid in the interpretation of infrared (IR) and nuclear magnetic resonance (NMR) spectra. All the ethers prepared were purified by preparative thin‐layer chromatography (TLC) and crystallization. Their purity was found to be greater than 95%, as determined by TLC and GLC, supported by NMR and IR spectra. The isomeric 1‐ and 2‐glyceryl ethers were separated on Silica Gel G adsorbent layers impregnated with either sodium arsenite or boric acid and their TLC behavior interpreted, based on the polarity of the complexes formed. Melting point determinations indicated more than one polymorphic form. Comparison of IR and NMR spectra of the saturated and unsaturated isomeric glyceryl ethers, and various derivatives, demonstrated the applicability of these spectroscopy methods for characterization and structural determination, in addition to distinguishing between the two isomeric forms.
Structure of bovine milk fat triglycerides
Authors: Breckenridge W. C. , Kuksis A. 
Published: November 2006

AbstractThe triglycerides of bovine milk fat globules were isolated and separated into short, medium and long chain lengths by thin‐layer chromatography. The molecular weight distribution and the fatty acid composition of the component triglycerides was then separately determined by gas chromatography following argentation‐thin‐layer and preparative gas chromatography. Some 38 triglyceride types (28% of total), of which there could be up to 6 isomers, were specifically identified and quantitatively estimated. The quantitative estimates for the rest of the milk fat triglycerides were limited to much more complex glyceride groups. The results confirm the earlier claim that butyric and caproic acids occur in milk fat almost exclusively in combination with medium and long chain fatty acids.
The 9‐hexadecenoic and 11‐octadecenoic acid content of natural fats and oils
Authors: Kuemmel D. F. , Chapman L. R. 
Published: November 2006

AbstractThe monoenoic methyl esters from numerous fats and oils which contained appreciablecis‐9‐hexadecenoic acid (cis‐9‐16∶1) were isolated by liquid‐solid chromatography on silver nitrate‐silica gel. Analysis of the monoenes by packed and capillary column gas‐liquid chromatography showed that significant amounts ofcis‐11‐octadecenoic acid (cis‐11‐18∶1) were present in all samples. The amount ofcis‐11‐18∶1 found in the monoenoic methyl esters increased proportionally to logarithmic increases in thecis‐9‐16∶1 level. Most analyses reported in the literature also show this proportionality. This mathematical relationship suggests that chain elongation ofcis‐9‐16∶1 tocis‐11‐18∶1 is a biosynthetic pathway operative in a wide variety of species.
The structures of triglycerides from atherosclerotic plaques and other human tissues
Authors: Christie W. W. , Moore J. H. , Lorimer A. R. , Lawrie T. D. V. 
Published: November 2006

AbstractStereospecific analysis of trigly cerides isolated from human liver showed that these were much more asymmetric than the triglycerides from human adipose tissue. Heart muscle triglycerides were similar in structure to adipose tissue triglycerides. The triglycerides from aortic plaques were intermediate in structure between triglycerides of liver and adipose tissue.