Computer Graphics

We present algorithms and systems for interactive boundary computation of Boolean combinations of sculptured solids. The algorithm is applicable to all spline solids and computes an accurate boundary representation. To speed up the computation, the algorithm exploits parallelism at all stages. It has been implemented on a multi-processor SGI and takes one second on average per boolean operation to compute the boundary of high degree primitives. The system has also been integrated with an immersive design and manipulation environment. The resulting system is able to interactively evaluate boundaries of the models, display them for model validation and place them at appropriate position using collision detection algorithms. ¥ 16. Furthermore, algorithms for interactive collision detection and object placement need an exact description of the boundary 18. Other applications of boundary representation (B-rep) include computation of solid's mass properties. Main Contribution: We present fast, parallel algorithms and systems for computing the boundary of boolean combinations of sculptured solids. The resulting boundary is represented in terms of trimmed Bézier patches. Given two primc

Simple, low-cost and accurate genotyping methods for single nucleotide polymorphisms (SNPs) are in high demand in the post-genome-sequencing era. We present a graphical tool called SNPicker, implemented in Java, which significantly facilitates the design of mutagenic endonuclease restriction assays. SNPicker uses the online NEB REBASE to automatically scan for all possible designs of mutagenic primers that can facilitate the picking of mismatched PCR primers to artificially introduce or abolish a restriction site at the target SNP site. We successfully applied SNPicker in designing endonuclease restriction assays for 14 SNPs for the MTHFR gene, the Coagulation Factor II gene and the Coagulation Factor V gene. The SNP assays designed using SNPicker were cross-validated using the MassARRAY technology.

Procedural modeling deals with (semi-)automatic content generation by means of a program or procedure. Among other advantages, its data compression and the potential to generate a large variety of detailed content with reduced human intervention, have made procedural modeling attractive for creating virtual environments increasingly used in movies, games, and simulations. We survey procedural methods that are useful to generate features of virtual worlds, including terrains, vegetation, rivers, roads, buildings, and entire cities. In this survey, we focus particularly on the degree of intuitive control and of interactivity offered by each procedural method, because these properties are instrumental for their typical users: designers and artists. We identify the most promising research results that have been recently achieved, but we also realize that there is far from widespread acceptance of procedural methods among non-technical, creative professionals. We conclude by discussing some of the most important challenges of procedural modeling. PM has the potential to drastically reduce the amount of modeling effort required to create digital content. Furthermore, because its methods are often stochastic, PM can create a variety of results from one set of input parameters; e.g., a large number of tree models, all of the same species and age, but each with a unique structure and shape.

Immersive virtual environments (VEs) offer interactive, real-time visualization capabilities for engineers, architects, and scientists. This paper presents Virtual-SAP, an immersive VE application allowing users to assess building structures and their response to various environmental conditions through an interactive designbuild-test-redesign cycle. Virtual-SAP has three distinct user interfaces that support its use with a high-end, multitracker VE system, with a low-cost portable VE system, or on the desktop. Two of these interfaces have been proven highly usable in user testing, and the third will be tested soon. Virtual-SAP is being used for both research and education.

Background: Although a quantitative evaluation of cardiac chamber dimensions in pediatric echocardiography is often important, nomograms for these structures are limited. The aim of this study was to establish reliable echocardiographic nomograms of cardiac chamber diameters and areas in a wide population of children. Methods: A total of 1,091 Caucasian Italian healthy children (age range, 0 days to 17 years; 44.8% female) with body surface areas (BSAs) ranging from 0.12 to 1.8 m 2 were prospectively enrolled. Twenty-two two-dimensional and M-mode measurements of atrial and ventricular chamber diameters and areas were performed. Models using linear, logarithmic, exponential, and square-root relationships were tested. Heteroscedasticity was tested by the White test and the Breusch-Pagan test. Age, weight, height, and BSA, calculated by the Haycock formula, were used as the independent variables in different analyses to predict the mean value of each echocardiographic measurement. The influence of various confounders, including gender, type of delivery, prematurity, and interobserver variability, was also evaluated. Structured Z scores were then computed. Results: The Haycock formula provided the best fit and was used when presenting data as predicted values (mean 6 2 SDs) for a given BSA and within equations relating echocardiographic measurements to BSA. Confounders were not included in the final models, because they did not show significant effects for most of the measurements. Conclusions: Echocardiographic reference values are presented for chamber area and diameters, derived from a large population of healthy children. These data partly cover a gap in actual pediatric echocardiographic nomograms. Further studies are required to reinforce these data, as well as to evaluate other parameters and ethnicities.

We study the problem of computing a planar curve, restricted to lie between two given polygonal chains, such that the integral of the square of arc-length derivative of curvature along the curve is minimized. We introduce the minimum variation B-spline problem, which is a linearly constrained optimization problem over curves, defined by B-spline functions only. An empirical investigation indicates that this problem has one unique solution among all uniform quartic B-spline functions. Furthermore, we prove that, for any B-spline function, the convexity properties of the problem are preserved subject to a scaling and translation of the knot sequence defining the B-spline.

The purpose of this research is the analysis using meta-analysis of studies in the field of Educational Technology in Turkey and in the field is to demonstrate how to get to that trend. For this purpose, a total of 263 studies were analyzed including 98 theses and 165 articles published between 2010-2018. Purpose sampling method was used when selecting publications. In the research, while selecting articles and Technology used in journals. Publications have been reviewed under 11 criteria. Index, year of publication, research scope, method, education level, sample, number of samples, data collection methods, analysis techniques, and research tendency, research topics in Educational Technology Research in Turkey has revealed. The data is interpreted based on percentage and frequency and the results are shown using the table.

Стаття присвячена окремим аспектам процесу формування графічної компетентності майбутніх бакалаврів з комп'ютерних наук у системі професійної освіти з орієнтацією на сучасні вимоги ринку праці, потенційних роботодавців та потреби у особистісному та професійному становленні студента. Досліджено місце комп’ютерного дизайну у змісті професійної освіти майбутнього бакалавра з комп’ютерних наук, та висвітлено його педагогічний потенціал, як необхідного чинника модернізації змісту професійної підготовки фахівців у галузі комп’ютерних наук. Визначено комбінаторні можливості та міждисциплінарні зв’язки з дисциплінами циклу професійної підготовки

Some of the authors of this publication are also working on these related projects: Virtual reality environments for health professional education View project Parvati Dev Innovation in Learning, Inc. 154 PUBLICATIONS 2,746 CITATIONS SEE PROFILE All content following this page was uploaded by Parvati Dev on 11 August 2015.

Objective: Human body finite element models (FE-HBMs) are available in standard occupant or pedestrian postures. There is a need to have FE-HBMs in the same posture as a crash victim or to be configured in varying postures. Developing FE models for all possible positions is not practically viable. The current work aims at obtaining a posture-specific human lower extremity model by reconfiguring an existing one. Methodology: A graphics-based technique was developed to reposition the lower extremity of an FE-HBM by specifying the flexion–extension angle. Elements of the model were segregated into rigid (bones) and deformable components (soft tissues). The bones were rotated about the flexion–extension axis followed by rotation about the longitudinal axis to capture the twisting of the tibia. The desired knee joint movement was thus achieved. Geometric heuristics were then used to reposition the skin. A mapping defined over the space between bones and the skin was used to regenerate the soft tissues. Mesh smoothing was then done to augment mesh quality. Results: The developed method permits control over the kinematics of the joint and maintains the initial mesh quality of the model. For some critical areas (in the joint vicinity) where element distortion is large, mesh smoothing is done to improve mesh quality. Conclusions: A method to reposition the knee joint of a human body FE model was developed. Repositions of a model from 9 degrees of flexion to 90 degrees of flexion in just a few seconds without subjective interventions was demonstrated. Because the mesh quality of the repositioned model was maintained to a predefined level (typically to the level of a well-made model in the initial configuration), the model was suitable for subsequent simulations.

Subsurface scattering within translucent objects is a complex phenomenon. Designing and rendering this kind of material requires a faithful description of their aspects as well as a realistic simulation of their interaction with light. This paper presents an efficient rendering technique of multilayered translucent objects. We present a new method for modeling and rendering such complex organic materials made up of multiple layers of variable thickness. Based on the relief texture mapping algorithm, our method calculates the single scattering contribution for this kind of material in real-time using commodity graphics hardware. Our approach needs the calculation of distances traversed by a light ray through a translucent object. This calculation is required for evaluating the attenuation of light within the material. We use a surface approximation algorithm to quickly evaluate these distances. Our whole algorithm is implemented using pixel shaders.

In this paper, we thoroughly study a trilinear interpolation scheme previously proposed for the Body-Centered Cubic (BCC) lattice. We think that, up to now, this technique has not received the attention that it deserves. By a frequency-domain analysis we show that it can isotropically suppress those aliasing spectra that contribute most to the postaliasing effect. Furthermore, we present an efficient GPU implementation, which requires only six trilinear texture fetches per sample. Overall, we demonstrate that the trilinear interpolation on the BCC lattice is competitive to the linear box-spline interpolation in terms of both efficiency and image quality. As a generalization to higher-order reconstruction, we introduce DC-splines that are constructed by convolving a Discrete filter with a Continuous filter, and easy to adapt to the Face-Centered Cubic (FCC) lattice as well.

Metode ray tracing adalah salah satu metode render dalam grafika komputer tigadimensi yang mensimulasikan sifat-sifat fisik sinar di alam Dengan metode ray tracing, akan didapatkan citra hasil render dengan model pencahayaan yang realistis. Salah satu kelemahan roy ...

Physiological studies have shown that focal articular surface defects in the human knee may progress to degenerative arthritis. Although the risk of this evolutive process is multifactorial, defect size is one of the most important factors. In order to determine the influence of osteochondral defect size and location on the stress and strain concentrations around the defect rim, a finite element model of the human knee was developed. From our results, it became clear that the size and location of cartilage defects drastically affect to those variables. No stress concentration appeared around the rim of small defects, being the stress distribution mainly controlled by the meniscus contact. On the contrary, important rim stress concentration was found for large osteochondral defects. This alteration of the stress distribution has important clinical implications regarding the long-term integrity of the cartilage adjacent to osteochondral defects. ᭧ (E. Peña), [email protected] (B. Calvo), [email protected] (M. Martínez), [email protected] (M. Doblaré). 0010-4825/$ -see front matter ᭧

We developed a networked virtual reality system on which one could have live videoes with high iteractive usage. However, since a client in our system receives both live videoes and computer graphics objects continuously from a server while it is rendering the current frame of the virtual world, a quality of the presentation of the virtual space depends on the current available system resources on the client as well as network resources. In this paper, we discuss the notion of QoS for a networked VR system as an application level QoS which is based on the notion of an importance of presence (IoP) of objects in a virtual space calculated by a distance from a current user's position to the object and an angle from the user's perspective to the object. Then, we show a heuristic mapping mechanism of the application level QoS to a network level QoS which determines the allocation of bandwidth of videos and CG objects to maximize the presentation quality. We adopt bandwidth as a...

for early dissemination of its contents. In view of the transfer of copyright to the outside publisher, its distribution outside of IBM prior to publication should be limited to peer communications and specific requests. After outside publication, requests should be filled only by reprints or legally obtained copies of the article (e.g. , payment of royalties). Copies may be requested from IBM T.

Human anatomy it may be, but the airways that riddle the space behind our noses take on an alien aspect in this unearthly rendering created by Kai-hung Fung, a radiologist at the Pamela Youde Nethersole Eastern Hospital in Hong Kong. ... A computed tomography (CT) scan ...

The work station is the most important part of any CAD/CAM system in industrial operation. Uniform operating procedures and easy access to archives, engineering data, and product models are key requirements of a work station in an integrated system. Environmental and ergonomic aspects are also of increasing importance for the general acceptance of this technology. A work station should take into account the various backgrounds and training of the people who will use it.1 So far, however, most work stations employing interactive graphic displays have been designed to suit the available hardware features rather than the user's needs. The limited dynamics of storage tubes and raster displays inhibit interaction between the user and the computeri.e., man-machine communication. The effectiveness and ease of man-machine communication depend on the kinds of accommodations that a computing system accords the user. Appropriate channels, devices, protocols, and controlling parameters are needed for communication in either direction. But the real aim in constructing CAD/CAM systems should be to achieve man-model communication, a higher function than man-machine communication. Manmachine communication deals with the input and output devices required for the exchange of information between a computer and a user; man-model communication deals with the interactions necessary to define, interrogate, and confirm the computer-based model. In this article we refer to such interaction as "dialogs. " The model involved in the dialog is typically stored in virtual memory and often involves transfers via a database management system. To achieve successful man-model dialogs, a designer must have not only the tools and protocols of man-machine communication but also an unobstructed sense of the model and a feeling of free interaction. Available work stations Work stations, as we know them, take several different forms. They are usually categorized by their graphics capabilities, their processing power, their program

Human Interaction in meetings is one of the famous fields of social dynamics. Meeting is integral part of every organization. In this, meeting outcome is extracted using tree based approach. Meetings contents or conversation are available in forms such as audio, video and text. In this, pattern of meeting is extracted from text document. An interaction is represented in the form of tree. Meeting Output is generated using data mining technique. Firstly the contents are filtered, extracted and steamed. Secondly classification is done into six categories propose, comment, acknowledgement, request Info, ask Opinion, pos Opinion, and neg Opinion. Next the interaction tree is constructed which represent the interaction flow of meeting. Finally the meeting output is generated from interaction tree using frequent pattern mining algorithm. The behavior of person is determined which includes a person who proposed a lot of ideas, a person with positive or negative attitude.

The common tusk in computer gruphics is to visuulise models of real world objects. These models are often represented by triungulur mesh, which can be very large und complex (thousands or million triangles). Since we want U fust und inteructive munipulution with the models, we need either to improve our gruphics hurdwure or to find any method for reducing number of triangles in the mesh. We present here u fust ulgorithm for triungulur mesh reduction bused on the principle of mesh decimution.

Shared-address-space multiprocessors are effective vehicles for speeding up visualization and image synthesis algorithms. This article demonstrates excellent parallel speedups on some well-known sequential algorithms. S everal recent algorithms have substantially sped up complex and timeconsuming visualization tasks. In particular, novel algorithms for radiosity computation' and volume r e n d e r i r~g~.~ have demonstrated performance far superior to earlier methods. Despite these advances, visualization of complex scenes or data sets remains computationally expensive. Rendering a 256 x 256 x 256-voxel volume data set takes about 5 seconds per frame on a 100-MHz Silicon Graphics Indigo workstation using Levoy's ray-casting algorithm2 and about a second per frame using a new shear-warp algorithm.' These times are much larger than the 0.03 second per frame required for real-time rendering or the 0.1 second per frame required for interactive rendering. Realistic radiosity and ray-tracing computations are much more time-consuming.

We advocate the use of point sets to represent shapes. We provide a definition of a smooth manifold surface from a set of points close to the original surface. The definition is based on local maps from differential geometry, which are approximated by the method of moving least squares (MLS). The computation of points on the surface is local, which results in an out-of-core technique that can handle any point set. We show that the approximation error is bounded and present tools to increase or decrease the density of the points, thus allowing an adjustment of the spacing among the points to control the error. To display the point set surface, we introduce a novel point rendering technique. The idea is to evaluate the local maps according to the image resolution. This results in high quality shading effects and smooth silhouettes at interactive frame rates.

The Neural Networks have been used in several
areas, showing their potential but also their limitations. One of
the main limitations is the long time required for the training
process; this is not useful in the case of a fast training process
being required to respond to changes in the application domain.
A possible way to accelerate the learning process of a Neural
Network is to implement it in hardware, but due to the high cost
and the reduced flexibility of the original CPU implementation,
this solution is often not chosen. Recently the power of the graphic
processing unit (GPU), on the market, has increased and it has
started to be used in many applications. In particular a kind
of Neural Network named Radial Basis Function Network has
been used extensively, proving its power. However their limiting
time performances reduce their application in many areas. In this
paper, we describe a GPU implementation of the entire learning
process of a Radial Basis Function Network showing the ability to
reduce the computational cost by about two orders of magnitude
with respect to its CPU implementation.

La capacitat de les dades de transformar els nostres paisatges gràfics quotidians té uns precedents que van més enllà del nostre passat més immediat. Tot i que actualment es troben en l’epicentre de la gran majoria de contextos acadèmics, àmbits de negocis, conferències i exposicions, cal remarcar que l’entorn humà ha estat envoltat de dades des de fa segles. La invenció i evolució de les tecnologies informàtiques ha permès que els usos i les capacitats prospectives d’aquestes dades hagi augmentat exponencialment durant els inicis del segle XXI, gràcies també a la capacitat dels dispositius mòbils de generar i assimilar totes les dades que les societats informatitzades són capaces de generar en espais de temps molt breus.
Així doncs, aquest estudi versa sobre la capacitat de representació
gràfica que el Big Data està generant, a través d’infografies i visualitzacions de dades en el nostre paisatge visual quotidià, centrant els esforços en analitzar aquestes dues estructures gràfiques i el paper que desenvolupen i poden arribar a desenvolupar en la societat, a través de reflexions des de la mirada crítica del disseny.

In this paper,w ec onsider the problem of learning to predict the correct pose of a 3D object, assuming orthographic projection and 3D linear transformations. A neural network is trained to learn the desired mapping.F irst, we consider the problem of predicting all possible views that an object can produce.T his is performed by representing the object with a small number of reference views and using algebraic functions of views to construct the space of all possible views that the object can produce.F undamental to this procedurei sam ethodology based on Singular Value Decomposition and Interval Arithmetic for estimating of the ranges of values that the parameterso fa lgebraic functions can assume.Then, a neural network is trained using a number of views (training views) whicha re generated by sampling the space of views of the object. During learning,a training viewispresented to the inputs of the network which is required to respond at its outputs with the parameterso f the algebraic functions used to generate the viewf romt he reference views. Compared to similar approaches in the literature, the proposed approachh as the advantage that it does not requiret he 3D models of the objects or a large number of views, it is extendible to other types of projections, and it is morepractical for object recognition.

This paper presents fast algorithms for penetration and contact determination between general polyhedral models in dynamic environments. The main contribution is an extension of an earlier expected constant time algorithm between convex polytopes to detect penetrations and contacts. For each pair of non-convex polyhedral models, the algorithm uses the convex hull of each object to determine which regions of the objects are colliding. After identifying these regions, it uses a new dynamic technique, sweep and prune, to overcome the bottleneck of O(n 2) pairwise feature checks of these regions. The resulting algorithm has been implemented and in practice its performance in dynamic environments is O(n + m), where m corresponds to the number of feature pairs close to each other.

In order to construct a 3D model from a collection of 2D images of an object, an energy function is defined between the object's images and corresponding images of an articulated mesh in three dimensions. Repeated adjustment of the mesh to minimize the energy function results in a mesh that produces images which closely approximate the input images, that is to say that under the appropriate conditions it realizes a preconceived object. It has implications for model building, reverse engineering and computer vision. Minimization of the energy function is a multivariate problem of large scale with many local minima. We give an approach for solving this problem. For certain restricted, but useful applications, intuitive solutions to the minimization are consistently obtained. $

We present a new display mode of the results of an Octopus visual field examination, which allows for an easy and reliable assessment of the local and diffuse components of the disturbances of a visual field. Essentially, this display consists of the cumulative distribution of the local defect values. Application to typical cases is discussed.

We describe a process for compositing a live performance of an actor into a virtual set wherein the actor is consistently illuminated by the virtual environment. The Light Stage used in this work is a two-meter sphere of inward-pointing RGB light emitting diodes focused on the actor, where each light can be set to an arbitrary color and intensity to replicate a real-world or virtual lighting environment. We implement a digital two-camera infrared matting system to composite the actor into the background plate of the environment without affecting the visible-spectrum illumination on the actor. The color reponse of the system is calibrated to produce correct color renditions of the actor as illuminated by the environment. We demonstrate moving-camera composites of actors into real-world environments and virtual sets such that the actor is properly illuminated by the environment into which they are composited.

The recognition of daily human activities is a decisive interface component for more intuitive VR interactions. In this paper, we describe a hierarchical model of body actions based on fine-grained action primitives. The associated recognition algorithm allows on-the-fly identification of simultaneous actions. Measurements highlight robustness to participants' variability and high detection rates when using the full potential of the action model. An example illustrates an interaction with a virtual character driven by the participant's action recognition.

One of the key issues that need to be addressed in wireless sensor network field is how to create a most efficient energy system. Ad-hoc Networks are becoming an effective tool for many mission critical applications such as troop coordination, situational awareness Etc. Ad-hoc Networks having limited computation and communication resources. To unguaranteed connectivity to trust authorities make known solutions for trusted authorities make knows solutions for single hop wireless networks. In this Project I am presenting A  Distinct Authentication Key for New TAM Protocol For large scale dense ad-hoc networks. TAM exploits network clusters to reduce overhead and ensure scalability. Multicast traffic with in a cluster employs a “One way hash function” chain in order to authenticate the message source. Cross cluster multicast traffic includes Message Authentication Codes (MAC’s) that are based on a set of keys. Result in terms of bandwidth overhead and delivery delay

Binary image compression is desirable for a wide range of applications, such as digital libraries, map archives, fingerprint databases, facsimile, etc. In this paper, we present a new highly efficient algorithm for lossless binary image compression. The proposed algorithm introduces a new method, direct redundancy elimination, to efficiently exploit the two-dimensional redundancy of an image, as well as a novel

The two-dimensional "hidden-line" problem is the Index Terms-Computer graphics, hidden-line problem, invis-technical drawAing of an object in which the visible edges ible lines, polygons, visible-edge determination. of the object are represented by solid lines and the invisible edges, that is, those hidden from view by parts of Manuscript

Perhaps, this is actually the used technique nowadays mostly. Specifically, for E-commerce people are using this technique atlanta divorce attorneys sector. Whenever it really is item advertisement or web business you need to afford this technique.

Let’s evidently find out about background removal.

In simple words, it denotes the task of erasing the behind scene from a graphic. That’s the good reason it is referred to as background removal. A issue can floats to your brain that what's the motive behind it to delete a history. Let me reply this and makes the plain thing clear.

We describe a method for the visual interactive simulation of wires contacting with rigid multibodies. The physical model used is a hybrid combining lumped elements and massless quasistatic representations. The latter is based on a kinematic constraint preserving the total length of the wire along a segmented path which can involve multiple bodies simultaneously and dry frictional contact nodes used for roping, lassoing and fastening. These nodes provide stick and slide friction along edges of the contacting geometries. The lumped element resolution is adapted dynamically based on local stability criteria, becoming coarser as the tension increases, and up to the purely kinematic representation. Kinematic segments and contact nodes are added and deleted and propagated based on contact geometries and dry friction configurations. The method gives dramatic increase on both performance and robustness because it quickly decimates superfluous nodes without loosing stability, yet adapts to complex configurations with many contacts and high curvature, keeping a fixed, large integration time step. Numerical results demonstrating the performance and stability of the adaptive multiresolution scheme are presented along with an array of representative simulation examples illustrating the versatility of the frictional contact model.