Results 1  10
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33
Interactive Manipulation of Rigid Body Simulations
 SIGGRAPH 2000
, 2000
"... Physical simulation of dynamic objects has become commonplace in computer graphics because it produces highly realistic animations. In this paradigm the animator provides few physical parameters such as the objects' initial positions and velocities, and the simulator automatically generates realisti ..."
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Cited by 69 (7 self)
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Physical simulation of dynamic objects has become commonplace in computer graphics because it produces highly realistic animations. In this paradigm the animator provides few physical parameters such as the objects' initial positions and velocities, and the simulator automatically generates realistic motions. The resulting motion, however, is difficult to control because even a small adjustment of the input parameters can drastically affect the subsequent motion. Furthermore, the animator often wishes to change the endresult of the motion instead of the initial physical parameters. We describe
An Active Contour Model For Mapping The Cortex
 IEEE TRANS. ON MEDICAL IMAGING
, 1995
"... A new active contour model for finding and mapping the outer cortex in brain images is developed. A crosssection of the brain cortex is modeled as a ribbon, and a constant speed mapping of its spine is sought. A variational formulation, an associated force balance condition, and a numerical approac ..."
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Cited by 64 (13 self)
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A new active contour model for finding and mapping the outer cortex in brain images is developed. A crosssection of the brain cortex is modeled as a ribbon, and a constant speed mapping of its spine is sought. A variational formulation, an associated force balance condition, and a numerical approach are proposed to achieve this goal. The primary difference between this formulation and that of snakes is in the specification of the external force acting on the active contour. A study of the uniqueness and fidelity of solutions is made through convexity and frequency domain analyses, and a criterion for selection of the regularization coefficient is developed. Examples demonstrating the performance of this method on simulated and real data are provided.
Contour Map Matching for Event Detection in Sensor Networks
 In SIGMOD
, 2006
"... Many sensor network applications, such as object tracking and disaster monitoring, require effective techniques for event detection. In this paper, we propose a novel event detection mechanism based on matching the contour maps of innetwork sensory data distribution. Our key observation is that eve ..."
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Cited by 28 (7 self)
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Many sensor network applications, such as object tracking and disaster monitoring, require effective techniques for event detection. In this paper, we propose a novel event detection mechanism based on matching the contour maps of innetwork sensory data distribution. Our key observation is that events in sensor networks can be abstracted into spatiotemporal patterns of sensory data and that pattern matching can be done efficiently through contour map matching. Therefore, we propose simple SQL extensions to allow users to specify common types of events as patterns in contour maps and study energyefficient techniques of contour map construction and maintenance for our patternbased event detection. Our experiments with synthetic workloads derived from a realworld coal mine surveillance application validate the effectiveness and efficiency of our approach. 1.
Stereo in the Presence of Specular Reflection
 IN ICCV
, 1995
"... The problem of accurate depth estimation using stereo in the presence of specular reflection is addressed. Specular reflection is viewpoint dependent and can cause large intensity differences at corresponding points. Hence, mismatches can result causing significant depth errors. Current stereo algor ..."
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Cited by 27 (1 self)
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The problem of accurate depth estimation using stereo in the presence of specular reflection is addressed. Specular reflection is viewpoint dependent and can cause large intensity differences at corresponding points. Hence, mismatches can result causing significant depth errors. Current stereo algorithms largely ignore specular reflection which is a fundamental reflection phenomenon from surfaces, both smooth and rough. We analyzed the physics of specular reflection and the geometry of stereopsis which led us to an interesting relationship between stereo vergence, surface roughness, and the likelihood of a correct match. Given the lower bound on surface roughness, an optimal binocular stereo configuration can be determined which maximizes precision in depth estimation despite specular reflection. However, surface roughness is difficult to estimate in unstructured environments. Therefore, multiple view configurations independent of surface roughness are determined such that at each scen...
EcliPSe: A System for High Performance Concurrent Simulation
, 1991
"... this paper describes our approach from the system point of view. The programming interface is described in detail in the next section, following which the design and salient implementation aspects are discussed. Representative results from a few simulation systems are then reported, and the conclud ..."
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Cited by 20 (10 self)
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this paper describes our approach from the system point of view. The programming interface is described in detail in the next section, following which the design and salient implementation aspects are discussed. Representative results from a few simulation systems are then reported, and the concluding section discusses some of the critical issues in such an approach, the implications for applications other than stochastic simulation, and ongoing and future work
On Splines and Their Minimum Properties
 J. Math. Mech
, 1966
"... Introduction. It is the purpose of this note to show that the several minimum properties of odd degree polynomial spline functions [4, 18] all derive from the fact that spline functions are representers of appropriate bounded linear functionals in an appropriate Hilbert space. (These results were fi ..."
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Cited by 16 (1 self)
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Introduction. It is the purpose of this note to show that the several minimum properties of odd degree polynomial spline functions [4, 18] all derive from the fact that spline functions are representers of appropriate bounded linear functionals in an appropriate Hilbert space. (These results were first announced in Notices, Amer. Math. Soc., 11 (1964) 681.) In particular, spline interpolation is a process of best approximation, i.e., of orthogonal projection, in this Hilbert space. This observation leads to a generalization of the notion of spline function. The fact that such generalized spline functions retain all the minimum properties of the polynomial splines, follows from familiar facts about orthogonal projections in Hilbert space. 1. Polynomial splines and their minimum properties. A polynomial spline function, s(x), of degree m # 0, having the n
The virtual mesh: A geometric abstraction for efficiently computing radiosity
 ACM Transactions on Graphics
"... In this paper, we introduce a generalpurpose method for computing radiosity on scenes made of parametric surfaces with arbitrary trimming curves. By contrast with past approaches that require a tessellation of the input surfaces (be it made up of triangles or patches with simple trimming curves) or ..."
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Cited by 13 (6 self)
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In this paper, we introduce a generalpurpose method for computing radiosity on scenes made of parametric surfaces with arbitrary trimming curves. By contrast with past approaches that require a tessellation of the input surfaces (be it made up of triangles or patches with simple trimming curves) or some form of geometric approximation, our method takes fully advantage of the rich and compact mathematical representation of objects. At its core lies the virtual mesh, an abstraction of the input geometry that allows complex shapes to be illuminated as if they were simple primitives. The virtual mesh is a collection of normalized square domains to which the input surfaces are mapped while preserving their energy properties. Radiosity values are then computed on these supports before being lifted back to the original surfaces. To demonstrate the power of our method, we describe a highorder wavelet radiosity implementation that uses the virtual mesh. Examples of objects and environments, designed for interactive applications or virtual reality, are presented. They prove that, by exactly integrating curved surfaces in the resolution process, the virtual mesh allows complex scenes to be rendered more quickly, more accurately and much more naturally than with previously known methods.
A computational model for multivariable differential calculus
 Proc. FoSSaCS 2005, LNCS
, 2005
"... Abstract. We introduce a domaintheoretic computational model for multivariable differential calculus, which for the first time gives rise to data types for differentiable functions. The model, a continuous Scott domain for differentiable functions of n variables, is built as a subdomain of the pro ..."
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Cited by 10 (6 self)
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Abstract. We introduce a domaintheoretic computational model for multivariable differential calculus, which for the first time gives rise to data types for differentiable functions. The model, a continuous Scott domain for differentiable functions of n variables, is built as a subdomain of the product of n + 1 copies of the function space on the domain of intervals by tupling together consistent information about locally Lipschitz (piecewise differentiable) functions and their differential properties (partial derivatives). The main result of the paper is to show, in two stages, that consistency is decidable on basis elements, which implies that the domain can be given an effective structure. First, a domaintheoretic notion of line integral is used to extend Green’s theorem to intervalvalued vector fields and show that integrability of the derivative information is decidable. Then, we use techniques from the theory of minimal surfaces to construct the least and the greatest piecewise linear functions that can be obtained from a tuple of n + 1 rational step functions, assuming the integrability of the ntuple of the derivative part. This provides an algorithm to check consistency on the rational basis elements of the domain, giving an effective framework for multivariable differential calculus. 1
Binocular Stereo in the Presence of Specular Reflection
 IN ARPA
, 1994
"... We address the problem of accurate depth estimation using stereo in the presence of specular reflection. Specular reflection is viewpoint dependent and can cause large intensity differences at corresponding points in stereo images. Hence, mismatches could result causing significant depth errors. Our ..."
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Cited by 3 (1 self)
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We address the problem of accurate depth estimation using stereo in the presence of specular reflection. Specular reflection is viewpoint dependent and can cause large intensity differences at corresponding points in stereo images. Hence, mismatches could result causing significant depth errors. Our approach seeks to determine a scene independent optimal stereo configuration such that intensity mismatches are limited and depth resolution is maximized, simultaneously. A key feature of this approach is we do not seek to eliminate or avoid specular reflection, but rather minimize its effects on stereo matching. The scheme is general as it is not restricted to specific reflectance models or image correspondence schemes. Experiments on real surfaces confirms its viability.
MultipleInput MultipleOutput Wireless Communication Systems with Cochannel Interference
, 2003
"... To meet the requirement of very high data rates for wireless Internet and multimedia services, multiple transmitting and multiple receiving antennas have been proposed for fourth generation wireless systems. In cellular systems, performance is limited by fading and cochannel interference from other ..."
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Cited by 3 (2 self)
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To meet the requirement of very high data rates for wireless Internet and multimedia services, multiple transmitting and multiple receiving antennas have been proposed for fourth generation wireless systems. In cellular systems, performance is limited by fading and cochannel interference from other users. Most of the current studies on multipleinput multipleoutput (MIMO) systems assume that the cochannel interference is both spatially and temporally white. In this thesis, we focus on MIMO systems under both spatially and temporally colored interference. In MIMO systems, diversity gain is effectively achieved by the multiple receiving antennas. Outage performances of several receive diversity schemes are analytically compared for an interferencelimited environment in a Rayleigh fading channel. We investigate three diversity schemes: a practical variation of maximalratio combining, equalgain combining (EGC) and selection combining (SC). An exact outage probability expression is derived for EGC by accurately calculating the interference power at the output of the combiner. It is found that the relative performance between EGC and SC depends on the