bluuebunny/crossref_metadata_2025 huggingface dataset:
Subspace integration with local deformations
Authors: Harmon David , Zorin Denis
Published: July 2013

Subspace techniques greatly reduce the cost of nonlinear simulation by approximating deformations with a small custom basis. In order to represent the deformations well (in terms of a global metric), the basis functions usually have global support, and cannot capture localized deformations. While reduced-space basis functions can be localized to some extent, capturing truly local deformations would still require a very large number of precomputed basis functions, significantly degrading both precomputation and online performance. We present an efficient approach to handling local deformations that cannot be predicted, most commonly arising from contact and collisions, by augmenting the subspace basis with custom functions derived from
analytic
solutions to static loading problems. We also present a new cubature scheme designed to facilitate fast computation of the necessary runtime quantities while undergoing a changing basis. Our examples yield a two order of magnitude speedup over full-coordinate simulations, striking a desirable balance between runtime speeds and expressive ability.
Co-hierarchical analysis of shape structures
Authors: van Kaick Oliver , Xu Kai , Zhang Hao , Wang Yanzhen , Sun Shuyang , Shamir Ariel , Cohen-Or Daniel
Published: July 2013

We introduce an unsupervised
co-hierarchical
analysis of a
set
of shapes, aimed at discovering their hierarchical part structures and revealing relations between geometrically dissimilar yet functionally equivalent shape parts across the set. The core problem is that of
representative co-selection
. For each shape in the set, one representative hierarchy (tree) is selected from among many possible interpretations of the hierarchical structure of the shape. Collectively, the selected tree representatives maximize the
within-cluster
structural similarity among them. We develop an iterative algorithm for representative co-selection. At each step, a novel
cluster-and-select
scheme is applied to a set of candidate trees for all the shapes. The tree-to-tree distance for clustering caters to structural shape analysis by focusing on spatial arrangement of shape parts, rather than their geometric details. The final set of representative trees are unified to form a structural co-hierarchy. We demonstrate co-hierarchical analysis on families of man-made shapes exhibiting high degrees of geometric and finer-scale structural variabilities.
Adaptive image synthesis for compressive displays
Authors: Heide Felix , Wetzstein Gordon , Raskar Ramesh , Heidrich Wolfgang
Published: July 2013

Recent years have seen proposals for exciting new computational display technologies that arecompressivein the sense that they generate high resolution images or light fields with relatively few display parameters. Image synthesis for these types of displays involves two major tasks: sampling and rendering high-dimensional target imagery, such as light fields or time-varying light fields, as well as optimizing the display parameters to provide a good approximation of the target content.

In this paper, we introduce an adaptive optimization framework for compressive displays that generates high quality images and light fields using only a fraction of the total plenoptic samples. We demonstrate the framework for a large set of display technologies, including several types of auto-stereoscopic displays, high dynamic range displays, and high-resolution displays. We achieve significant performance gains, and in some cases are able to process data that would be infeasible with existing methods.
Injective and bounded distortion mappings in 3D
Authors: Aigerman Noam , Lipman Yaron
Published: July 2013

We introduce an efficient algorithm for producing provably injective mappings of tetrahedral meshes with strict bounds on their tetrahedra aspect-ratio distortion.

The algorithm takes as input a simplicial map (e.g., produced by some common deformation or volumetric parameterization technique) andprojectsit on the space of injective and bounded-distortion simplicial maps. Namely, finds a similar map that is both bijective and bounded-distortion. As far as we are aware, this is the first algorithm to produce injective or bounded-distortion simplicial maps of tetrahedral meshes. The construction of the algorithm was made possible due to a novel closed-form solution to the problem of finding the closest orientation-preserving bounded-distortion matrix to an arbitrary matrix in three (and higher) dimensions.

The algorithm is shown to have quadratic convergence, usually not requiring more than a handful of iterations to converge. Furthermore, it is readily generalized to simplicial maps of any dimension, including mixed dimensions. Finally, it can deal with different distortion spaces, such as bounded isometric distortion. During experiments we found the algorithm useful for producing bijective and bounded-distortion volume parameterizations and deformations of tetrahedral meshes, and improving tetrahedral meshes, increasing the tetrahedra quality produced by state-of-the-art techniques.
On the equilibrium of simplicial masonry structures
Authors: de Goes Fernando , Alliez Pierre , Owhadi Houman , Desbrun Mathieu
Published: July 2013

We present a novel approach for the analysis and design of self-supporting simplicial masonry structures. A finite-dimensional formulation of their compressive stress field is derived, offering a new interpretation of thrust networks through numerical homogenization theory. We further leverage geometric properties of the resulting force diagram to identify a set of reduced coordinates characterizing the equilibrium of simplicial masonry. We finally derive computational form-finding tools that improve over previous work in efficiency, accuracy, and scalability.
InfraStructs
Authors: Willis Karl D. D. , Wilson Andrew D.
Published: July 2013

We introduce
InfraStructs
, material-based tags that embed information inside digitally fabricated objects for imaging in the Terahertz region. Terahertz imaging can safely penetrate many common materials, opening up new possibilities for encoding hidden information as part of the fabrication process. We outline the design, fabrication, imaging, and data processing steps to fabricate information inside physical objects. Prototype tag designs are presented for location encoding, pose estimation, object identification, data storage, and authentication. We provide detailed analysis of the constraints and performance considerations for designing
InfraStruct
tags. Future application scenarios range from production line inventory, to customized game accessories, to mobile robotics.
Modular flux transfer
Authors: Zhao Shuang , Hašan Miloš , Ramamoorthi Ravi , Bala Kavita
Published: July 2013

The highest fidelity images to date of complex materials like cloth use extremely high-resolution volumetric models. However, rendering such complex volumetric media is expensive, with brute-force path tracing often the only viable solution. Fortunately, common volumetric materials (fabrics, finished wood, synthesized solid textures) are structured, with repeated patterns approximated by tiling a small number of exemplar blocks. In this paper, we introduce a precomputation-based rendering approach for such volumetric media with repeated structures based on a modular transfer formulation. We model each exemplar block as a voxel grid and precompute voxel-to-voxel, patch-to-patch, and patch-to-voxel flux transfer matrices. At render time, when blocks are tiled to produce a high-resolution volume, we accurately compute low-order scattering, with modular flux transfer used to approximate higher-order scattering. We achieve speedups of up to 12× over path tracing on extremely complex volumes, with minimal loss of quality. In addition, we demonstrate that our approach outperforms photon mapping on these materials.
Image-based reconstruction and synthesis of dense foliage
Authors: Bradley Derek , Nowrouzezahrai Derek , Beardsley Paul
Published: July 2013

Flora is an element in many computer-generated scenes. But trees, bushes and plants have complex geometry and appearance, and are difficult to model manually. One way to address this is to capture models directly from the real world. Existing techniques have focused on extracting macro structure such as the branching structure of trees, or the structure of broad-leaved plants with a relatively small number of surfaces. This paper presents a finer scale technique to demonstrate for the first time the processing of densely leaved foliage - computation of 3D structure, plus extraction of statistics for leaf shape and the configuration of neighboring leaves. Our method starts with a mesh of a single exemplar leaf of the target foliage. Using a small number of images, point cloud data is obtained from multi-view stereo, and the exemplar leaf mesh is fitted non-rigidly to the point cloud over several iterations. In addition, our method learns a statistical model of leaf shape and appearance during the reconstruction phase, and a model of the transformations between neighboring leaves. This information is useful in two ways - to augment and increase leaf density in reconstructions of captured foliage, and to synthesize new foliage that conforms to a user-specified layout and density. The result of our technique is a dense set of captured leaves with realistic appearance, and a method for leaf synthesis. Our approach excels at reconstructing plants and bushes that are primarily defined by dense leaves and is demonstrated with multiple examples.
Qualitative organization of collections of shapes via quartet analysis
Authors: Huang Shi-Sheng , Shamir Ariel , Shen Chao-Hui , Zhang Hao , Sheffer Alla , Hu Shi-Min , Cohen-Or Daniel
Published: July 2013

We present a method for organizing a heterogeneous collection of 3D shapes for overview and exploration. Instead of relying on quantitative distances, which may become unreliable between dissimilar shapes, we introduce aqualitativeanalysis which utilizes multiple distance measures but only in cases where the measures can be reliably compared. Our analysis is based on the notion ofquartets, each defined by two pairs of shapes, where the shapes in each pair are close to each other, but far apart from the shapes in the other pair. Combining the information from many quartets computed across a shape collection using several distance measures, we create a hierarchical structure we callcategorization treeof the shape collection. This tree satisfies the topological (qualitative) constraints imposed by the quartets creating an effective organization of the shapes. We present categorization trees computed on various collections of shapes and compare them to ground truth data from human categorization. We further introduce the concept ofdegree of separationchart for every shape in the collection and show the effectiveness of using it for interactive shapes exploration.
Implicit skinning
Authors: Vaillant Rodolphe , Barthe Loïc , Guennebaud Gaël , Cani Marie-Paule , Rohmer Damien , Wyvill Brian , Gourmel Olivier , Paulin Mathias
Published: July 2013

Geometric skinning techniques, such as smooth blending or dual-quaternions, are very popular in the industry for their high performances, but fail to mimic realistic deformations. Other methods make use of physical simulation or control volume to better capture the skin behavior, yet they cannot deliver real-time feedback. In this paper, we present the first purely geometric method handling skin contact effects and muscular bulges in real-time. The insight is to exploit the advanced composition mechanism of volumetric, implicit representations for correcting the results of geometric skinning techniques. The mesh is first approximated by a set of implicit surfaces. At each animation step, these surfaces are combined in real-time and used to adjust the position of mesh vertices, starting from their smooth skinning position. This deformation step is done without any loss of detail and seamlessly handles contacts between skin parts. As it acts as a post-process, our method fits well into the standard animation pipeline. Moreover, it requires no intensive computation step such as collision detection, and therefore provides real-time performances.
Cardinality-constrained texture filtering
Authors: Manson Josiah , Schaefer Scott
Published: July 2013

We present a method to create high-quality sampling filters by combining a prescribed number of texels from several resolutions in a mipmap. Our technique provides fine control over the number of texels we read per texture sample so that we can scale quality to match a memory bandwidth budget. Our method also has a fixed cost regardless of the filter we approximate, which makes it feasible to approximate higher-quality filters such as a Lánczos 2 filter in real-time rendering. To find the best set of texels to represent a given sampling filter and what weights to assign those texels, we perform a cardinality-constrained least-squares optimization of the most likely candidate solutions and encode the results of the optimization in a small table that is easily stored on the GPU. We present results that show we accurately reproduce filters using few texel reads and that both quality and speed scale smoothly with available bandwidth. When using four or more texels per sample, our image quality exceeds that of trilinear interpolation.
Style and abstraction in portrait sketching
Authors: Berger Itamar , Shamir Ariel , Mahler Moshe , Carter Elizabeth , Hodgins Jessica
Published: July 2013

We use a data-driven approach to study both style and abstraction in sketching of a human face. We gather and analyze data from a number of artists as they sketch a human face from a reference photograph. To achieve different levels of abstraction in the sketches, decreasing time limits were imposed -- from four and a half minutes to fifteen seconds. We analyzed the data at two levels: strokes and geometric shape. In each, we create a model that captures both the style of the different artists and the process of abstraction. These models are then used for a portrait sketch synthesis application. Starting from a novel face photograph, we can synthesize a sketch in the various artistic styles and in different levels of abstraction.
Phase-based video motion processing
Authors: Wadhwa Neal , Rubinstein Michael , Durand Frédo , Freeman William T.
Published: July 2013

We introduce a technique to manipulate small movements in videos based on an analysis of motion in complex-valued image pyramids. Phase variations of the coefficients of a complex-valued steerable pyramid over time correspond to motion, and can be temporally processed and amplified to reveal imperceptible motions, or attenuated to remove distracting changes. This processing does not involve the computation of optical flow, and in comparison to the previous Eulerian Video Magnification method it supports larger amplification factors and is significantly less sensitive to noise. These improved capabilities broaden the set of applications for motion processing in videos. We demonstrate the advantages of this approach on synthetic and natural video sequences, and explore applications in scientific analysis, visualization and video enhancement.
Worst-case structural analysis
Authors: Zhou Qingnan , Panetta Julian , Zorin Denis
Published: July 2013

Direct digital manufacturing is a set of rapidly evolving technologies that provide easy ways to manufacture highly customized and unique products. The development pipeline for such products is radically different from the conventional manufacturing pipeline: 3D geometric models are designed by users often with little or no manufacturing experience, and sent directly to the printer. Structural analysis on the user side with conventional tools is often unfeasible as it requires specialized training and software. Trial-and-error, the most common approach, is time-consuming and expensive.

We present a method that would identify structural problems in objects designed for 3D printing
based on geometry and material properties only
, without specific assumptions on loads and manual load setup. We solve a constrained optimization problem to determine the "worst" load distribution for a shape that will cause high local stress or large deformations. While in its general form this optimization has a prohibitively high computational cost, we demonstrate that an approximate method makes it possible to solve the problem rapidly for a broad range of printed models. We validate our method both computationally and experimentally and demonstrate that it has good predictive power for a number of diverse 3D printed shapes.
Sketch2Scene
Authors: Xu Kun , Chen Kang , Fu Hongbo , Sun Wei-Lun , Hu Shi-Min
Published: July 2013

This work presents
Sketch2Scene
, a framework that automatically turns a freehand sketch drawing inferring multiple scene objects to semantically valid, well arranged scenes of 3D models. Unlike the existing works on sketch-based search and composition of 3D models, which typically process individual sketched objects one by one, our technique performs
co-retrieval
and
co-placement
of 3D relevant models by jointly processing the sketched objects. This is enabled by summarizing functional and spatial relationships among models in a large collection of 3D scenes as
structural groups
. Our technique greatly reduces the amount of user intervention needed for sketch-based modeling of 3D scenes and fits well into the traditional production pipeline involving concept design followed by 3D modeling. A pilot study indicates that it is promising to use our technique as an alternative but more efficient tool of standard 3D modeling for 3D scene construction.
Generating and exploring good building layouts
Authors: Bao Fan , Yan Dong-Ming , Mitra Niloy J. , Wonka Peter
Published: July 2013

Good building layouts are required to conform to regulatory guidelines, while meeting certain quality measures. While different methods can sample the space of such good layouts, there exists little support for a user to understand and systematically explore the samples. Starting from a discrete set of good layouts, we analytically characterize the local shape space of good layouts around each initial layout, compactly encode these spaces, and link them to support transitions across the different local spaces. We represent such transitions in the form of a portal graph. The user can then use the portal graph, along with the family of local shape spaces, to globally and locally explore the space of good building layouts. We use our framework on a variety of different test scenarios to showcase an intuitive design, navigation, and exploration interface.
Computational design of actuated deformable characters
Authors: Skouras Mélina , Thomaszewski Bernhard , Coros Stelian , Bickel Bernd , Gross Markus
Published: July 2013

We present a method for fabrication-oriented design of actuated deformable characters that allows a user to automatically create physical replicas of digitally designed characters using rapid manufacturing technologies. Given a deformable character and a set of target poses as input, our method computes a small set of actuators along with their locations on the surface and optimizes the internal material distribution such that the resulting character exhibits the desired deformation behavior. We approach this problem with a dedicated algorithm that combines finite-element analysis, sparse regularization, and constrained optimization. We validate our pipeline on a set of two- and three-dimensional example characters and present results in simulation and physically-fabricated prototypes.
Fabricating BRDFs at high spatial resolution using wave optics
Authors: Levin Anat , Glasner Daniel , Xiong Ying , Durand Frédo , Freeman William , Matusik Wojciech , Zickler Todd
Published: July 2013

Recent attempts to fabricate surfaces with custom reflectance functions boast impressive angular resolution, yet their spatial resolution is limited. In this paper we present a method to construct spatially varying reflectance at a high resolution of up to 220dpi, orders of magnitude greater than previous attempts, albeit with a lower angular resolution. The resolution of previous approaches is limited by the machining, but more fundamentally, by the geometric optics model on which they are built. Beyond a certain scale geometric optics models break down and wave effects must be taken into account. We present an analysis of incoherent reflectance based on wave optics and gain important insights into reflectance design. We further suggest and demonstrate a practical method, which takes into account the limitations of existing micro-fabrication techniques such as photolithography to design and fabricate a range of reflection effects, based on wave interference.
Robust fairing via conformal curvature flow
Authors: Crane Keenan , Pinkall Ulrich , Schröder Peter
Published: July 2013

We present a formulation of Willmore flow for triangulated surfaces that permits extraordinarily large time steps and naturally preserves the quality of the input mesh. The main insight is that Willmore flow becomes remarkably stable when expressed in curvature space -- we develop the precise conditions under which curvature is allowed to evolve. The practical outcome is a highly efficient algorithm that naturally preserves texture and does not require remeshing during the flow. We apply this algorithm to surface fairing, geometric modeling, and construction of constant mean curvature (CMC) surfaces. We also present a new algorithm for length-preserving flow on planar curves, which provides a valuable analogy for the surface case.
Efficient preconditioning of laplacian matrices for computer graphics
Authors: Krishnan Dilip , Fattal Raanan , Szeliski Richard
Published: July 2013

We present a new multi-level preconditioning scheme for discrete Poisson equations that arise in various computer graphics applications such as colorization, edge-preserving decomposition for two-dimensional images, and geodesic distances and diffusion on three-dimensional meshes. Our approach interleaves the selection of fine-and coarse-level variables with the removal of weak connections between potential fine-level variables (
sparsification
) and the
compensation
for these changes by strengthening nearby connections. By applying these operations before each elimination step and repeating the procedure recursively on the resulting smaller systems, we obtain a highly efficient multi-level preconditioning scheme with linear time and memory requirements. Our experiments demonstrate that our new scheme outperforms or is comparable with other state-of-the-art methods, both in terms of operation count and wall-clock time. This speedup is achieved by the new method's ability to reduce the condition number of irregular Laplacian matrices as well as homogeneous systems. It can therefore be used for a wide variety of computational photography problems, as well as several 3D mesh processing tasks, without the need to carefully match the algorithm to the problem characteristics.
Spec2Fab
Authors: Chen Desai , Levin David I. W. , Didyk Piotr , Sitthi-Amorn Pitchaya , Matusik Wojciech
Published: July 2013

Multi-material 3D printing allows objects to be composed of complex, heterogenous arrangements of materials. It is often more natural to define a functional goal than to define the material composition of an object. Translating these functional requirements to fabri-cable 3D prints is still an open research problem. Recently, several specific instances of this problem have been explored (e.g., appearance or elastic deformation), but they exist as isolated, monolithic algorithms. In this paper, we propose an abstraction mechanism that simplifies the design, development, implementation, and reuse of these algorithms. Our solution relies on two new data structures: a
reducer tree
that efficiently parameterizes the space of material assignments and a
tuner network
that describes the optimization process used to compute material arrangement. We provide an application programming interface for specifying the desired object and for defining parameters for the
reducer tree
and
tuner network
. We illustrate the utility of our framework by implementing several fabrication algorithms as well as demonstrating the manufactured results.
Bundled camera paths for video stabilization
Authors: Liu Shuaicheng , Yuan Lu , Tan Ping , Sun Jian
Published: July 2013

We present a novel video stabilization method which models camera motion with a bundle of (multiple) camera paths. The proposed model is based on a mesh-based, spatially-variant motion representation and an adaptive, space-time path optimization. Our motion representation allows us to fundamentally handle parallax and rolling shutter effects while it does not require long feature trajectories or sparse 3D reconstruction. We introduce the 'as-similar-as-possible' idea to make motion estimation more robust. Our space-time path smoothing adaptively adjusts smoothness strength by considering discontinuities, cropping size and geometrical distortion in a unified optimization framework. The evaluation on a large variety of consumer videos demonstrates the merits of our method.
Optimizing color consistency in photo collections
Authors: HaCohen Yoav , Shechtman Eli , Goldman Dan B. , Lischinski Dani
Published: July 2013

With dozens or even hundreds of photos in today's digital photo albums, editing an entire album can be a daunting task. Existing automatic tools operate on individual photos without ensuring consistency of appearance between photographs that share content. In this paper, we present a new method for consistent editing of photo collections. Our method automatically enforces consistent appearance of images that share content without any user input. When the user does make changes to selected images, these changes automatically propagate to other images in the collection, while still maintaining as much consistency as possible. This makes it possible to interactively adjust an entire photo album in a consistent manner by manipulating only a few images.

Our method operates by efficiently constructing a graph with edges linking photo pairs that share content. Consistent appearance of connected photos is achieved by globally optimizing a quadratic cost function over the entire graph, treating user-specified edits as constraints in the optimization. The optimization is fast enough to provide interactive visual feedback to the user. We demonstrate the usefulness of our approach using a number of personal and professional photo collections, as well as internet collections.
AIREAL
Authors: Sodhi Rajinder , Poupyrev Ivan , Glisson Matthew , Israr Ali
Published: July 2013

AIREAL is a novel haptic technology that delivers effective and expressive tactile sensations in free air, without requiring the user to wear a physical device. Combined with interactive computers graphics, AIREAL enables users to feel virtual 3D objects, experience free air textures and receive haptic feedback on gestures performed in free space. AIREAL relies on air vortex generation directed by an actuated flexible nozzle to provide effective tactile feedback with a 75 degrees field of view, and within an 8.5cm resolution at 1 meter. AIREAL is a scalable, inexpensive and practical free air haptic technology that can be used in a broad range of applications, including gaming, mobile applications, and gesture interaction among many others. This paper reports the details of the AIREAL design and control, experimental evaluations of the device's performance, as well as an exploration of the application space of free air haptic displays. Although we used vortices, we believe that the results reported are generalizable and will inform the design of haptic displays based on alternative principles of free air tactile actuation.
Thin skin elastodynamics
Authors: Li Duo , Sueda Shinjiro , Neog Debanga R. , Pai Dinesh K.
Published: July 2013

We present a novel approach for simulating thin hyperelastic skin. Real human skin is only a few millimeters thick. It can stretch and slide over underlying body structures such as muscles, bones, and tendons, revealing rich details of a moving character. Simulating such skin is challenging because it is in close contact with the body and shares its geometry. Despite major advances in simulating elastodynamics of cloth and soft bodies for computer graphics, such methods are difficult to use for simulating thin skin due to the need to deal with non-conforming meshes, collision detection, and contact response. We propose a novel Eulerian representation of skin that avoids all the difficulties of constraining the skin to lie on the body surface by working directly on the surface itself. Skin is modeled as a 2D hyperelastic membrane with arbitrary topology, which makes it easy to cover an entire character or object. Unlike most Eulerian simulations, we do not require a regular grid and can use triangular meshes to model body and skin geometry. The method is easy to implement, and can use low resolution meshes to animate high-resolution details stored in texture-like maps. Skin movement is driven by the animation of body shape prescribed by an artist or by another simulation, and so it can be easily added as a post-processing stage to an existing animation pipeline. We provide several examples simulating human and animal skin, and skin-tight clothes.
Folding and crumpling adaptive sheets
Authors: Narain Rahul , Pfaff Tobias , O'Brien James F.
Published: July 2013

We present a technique for simulating plastic deformation in sheets of thin materials, such as crumpled paper, dented metal, and wrinkled cloth. Our simulation uses a framework of adaptive mesh refinement to dynamically align mesh edges with folds and creases. This framework allows efficient modeling of sharp features and avoids bend locking that would be otherwise caused by stiff in-plane behavior. By using an explicit plastic embedding space we prevent remeshing from causing shape diffusion. We include several examples demonstrating that the resulting method realistically simulates the behavior of thin sheets as they fold and crumple.
3D shape regression for real-time facial animation
Authors: Cao Chen , Weng Yanlin , Lin Stephen , Zhou Kun
Published: July 2013

We present a real-time performance-driven facial animation system based on 3D shape regression. In this system, the 3D positions of facial landmark points are inferred by a regressor from 2D video frames of an ordinary web camera. From these 3D points, the pose and expressions of the face are recovered by fitting a user-specific blendshape model to them. The main technical contribution of this work is the 3D regression algorithm that learns an accurate, user-specific face alignment model from an easily acquired set of training data, generated from images of the user performing a sequence of predefined facial poses and expressions. Experiments show that our system can accurately recover 3D face shapes even for fast motions, non-frontal faces, and exaggerated expressions. In addition, some capacity to handle partial occlusions and changing lighting conditions is demonstrated.
Fourier analysis of stochastic sampling strategies for assessing bias and variance in integration
Authors: Subr Kartic , Kautz Jan
Published: July 2013

Each pixel in a photorealistic, computer generated picture is calculated by approximately integrating all the light arriving at the pixel, from the virtual scene. A common strategy to calculate these high-dimensional integrals is to average the estimates at stochastically sampled locations. The strategy with which the sampled locations are chosen is of utmost importance in deciding the quality of the approximation, and hence rendered image.

We derive connections between the spectral properties of stochastic sampling patterns and the first and second order statistics of estimates of integration using the samples. Our equations provide insight into the assessment of stochastic sampling strategies for integration. We show that the amplitude of the expected Fourier spectrum of sampling patterns is a useful indicator of the bias when used in numerical integration. We deduce that estimator variance is directly dependent on the variance of the sampling spectrum over multiple realizations of the sampling pattern. We then analyse Gaussian jittered sampling, a simple variant of jittered sampling, that allows a smooth trade-off of bias for variance in uniform (regular grid) sampling. We verify our predictions using spectral measurement, quantitative integration experiments and qualitative comparisons of rendered images.
Real-time drawing assistance through crowdsourcing
Authors: Limpaecher Alex , Feltman Nicolas , Treuille Adrien , Cohen Michael
Published: July 2013

We propose a new method for the large-scale collection and analysis of drawings by using a mobile game specifically designed to collect such data. Analyzing this crowdsourced drawing database, we build a spatially varying model of artistic consensus at the stroke level. We then present a surprisingly simple stroke-correction method which uses our artistic consensus model to improve strokes in real-time. Importantly, our auto-corrections run interactively and appear nearly invisible to the user while seamlessly preserving artistic intent. Closing the loop, the game itself serves as a platform for large-scale evaluation of the effectiveness of our stroke correction algorithm.
Realtime facial animation with on-the-fly correctives
Authors: Li Hao , Yu Jihun , Ye Yuting , Bregler Chris
Published: July 2013

We introduce a real-time and calibration-free facial performance capture framework based on a sensor with video and depth input. In this framework, we develop an adaptive PCA model using shape correctives that adjust on-the-fly to the actor's expressions through incremental PCA-based learning. Since the fitting of the adaptive model progressively improves during the performance, we do not require an extra capture or training session to build this model. As a result, the system is highly deployable and easy to use: it can faithfully track any individual, starting from just a single face scan of the subject in a neutral pose. Like many real-time methods, we use a linear subspace to cope with incomplete input data and fast motion. To boost the training of our tracking model with reliable samples, we use a well-trained 2D facial feature tracker on the input video and an efficient mesh deformation algorithm to snap the result of the previous step to high frequency details in visible depth map regions. We show that the combination of dense depth maps and texture features around eyes and lips is essential in capturing natural dialogues and nuanced actor-specific emotions. We demonstrate that using an adaptive PCA model not only improves the fitting accuracy for tracking but also increases the expressiveness of the retargeted character.
Near-exhaustive precomputation of secondary cloth effects
Authors: Kim Doyub , Koh Woojong , Narain Rahul , Fatahalian Kayvon , Treuille Adrien , O'Brien James F.
Published: July 2013

The central argument against data-driven methods in computer graphics rests on the curse of dimensionality: it is intractable to precompute "everything" about a complex space. In this paper, we challenge that assumption by using several thousand CPU-hours to perform a massive exploration of the space of secondary clothing effects on a character animated through a large motion graph. Our system continually explores the phase space of cloth dynamics, incrementally constructing a
secondary cloth motion graph
that captures the dynamics of the system. We find that it is possible to sample the dynamical space to a low visual error tolerance and that secondary motion graphs containing tens of gigabytes of raw mesh data can be compressed down to only tens of megabytes. These results allow us to capture the effect of high-resolution, off-line cloth simulation for a rich space of character motion and deliver it efficiently as part of an interactive application.
Putting holes in holey geometry
Authors: Bernstein Gilbert Louis , Wojtan Chris
Published: July 2013

This paper presents a method for computing topology changes for triangle meshes in an interactive geometric modeling environment. Most triangle meshes in practice do not exhibit desirable geometric properties, so we develop a solution that is independent of standard assumptions and robust to geometric errors. Specifically, we provide the first method for topology change applicable to arbitrary non-solid, non-manifold, non-closed, self-intersecting surfaces. We prove that this new method for topology change produces the expected conventional results when applied to solid (closed, manifold, non-self-intersecting) surfaces---that is, we prove a backwards-compatibility property relative to prior work. Beyond solid surfaces, we present empirical evidence that our method remains tolerant to a variety of surface aberrations through the incorporation of a novel error correction scheme. Finally, we demonstrate how topology change applied to non-solid objects enables wholly new and useful behaviors.
Wild in the Laboratory
Authors: Rooksby John
Published: July 2013

Suchman’s book
Plans and Situated Actions
has been influential in HCI (Human Computer Interaction). The book is often discussed with reference to ethnographic fieldwork, sometimes being cited as if it were a field study. However, the book uses examples from a laboratory study and contains criticisms of ethnography. This article explores how and why Suchman carried out a laboratory study. Based upon this exploration, it argues that social analysis in HCI does not necessitate fieldwork outside the laboratory. More broadly, the paper argues that an appreciation of Plans and Situated Actions can help in moving towards forms of social analysis that span both the laboratory and the world outside. If there is to be a “turn to the wild” in HCI, this should not be a turn away from the laboratory but a turn away from research methods that ignore human practice. This is not to defend laboratory experiments, but to defend laboratory-based studies that explicate technology in practice.
Empirical study of root cause analysis of software failure
Authors: Dalal Sandeep , Chhillar Rajender Singh
Published: July 2013

Root Cause Analysis (RCA) is the process of identifying project issues, correcting them and taking preventive actions to avoid occurrences of such issues in the future. Issues could be variance in schedule, effort, cost, productivity, expected results of software, performance parameters and customer satisfaction. RCA also involves collecting valid data, analyzing it, deriving metrics and finding root causes using RCA methods. In this paper we will do Root cause analysis of some severe software failures that happened in the past and of some failures in ongoing projects in the software Industry. We will also describe various RCA methods and processes used in the software Industry to reduce the chances of software failure.
A rule-based recommendation system for selection of software development life cycle models
Authors: Kumar Kuldeep , Kumar Sandeep
Published: July 2013

The selection of a software development life cycle (SDLC) model for a software project is highly dependent upon the characteristics of the software product to be developed. We classified software products according to characteristics that matter for SDLC selection. We surveyed literature to elicit recommendations for SDLC selection. We formalized our findings to present a rule based recommendation system that can be helpful to software developers in selecting the most appropriate SDLC model to be used for the development of a software product. We conducted an initial evaluation of our system. We believe our SDLC recommendation system provides useful hints for selecting an SDLC, and provides a base for validating and refining SDLC recommendation rules.
Study of empirical approaches to analyze the software metrics
Authors: Pandey Adesh Kr. , Agrawal C. P. , Sharma Arun , Sasikala P.
Published: July 2013

Software affects nearly every aspect of human lives. Software functional quality is a key to achieve industrial and business relevance, in particular to industrial development and growth.

Software metrics are important indicators to improve the processes and products in all organizations. They define baselines of quality and productivity and enable comparisons against industry averages that help in identifying opportunities for improvement. In addition, Software metrics design and analysis are major activities in the software development life cycle. Software metrics play a vital role in software cost, quality, scheduling, reliability and maintenance. There are various methods to decide which metrics should be used for which purposes. Attributes of a metric may be independent; or attributes may depend on one another.

Analytical Hierarchy Process (AHP) is used to assign weights to various parameters of a decision model when they are related to each other in a particular hierarchy. Analytical Network Process (ANP) and Fuzzy ANP are used to solve the decision problem, where attributes of decision parameters form dependency networks. The objective of this paper is to explore the possibilities of using empirical approaches like AHP, ANP and Fuzzy ANP to analyze the software metrics by measuring the weights of different attributes.
An automated tool for regression testing in web applications
Authors: Raina Shikha , Agarwal Arun Prakash
Published: July 2013

Regression testing of web applications is a costly activity as it tends to generate more test cases than the previous stages of software testing. This cost can be reduced significantly by identifying and testing only the modified parts of a web application. This will require locating the changes that have been introduced in the web application from the previous version that was tested.

In this paper we have introduced an automated tool for locating the changes in the web application which will thereby aid in effective regression testing of the application. This tool compromise of 3 parts, a) a web crawler that crawls the web application, b) an HTML DOM tree generator that generates the DOM tree for a specified web page, c) an comparator that compares the new DOM tree with a previous version of the DOM tree stored in our system.
CAME
Authors: Shareef Jawwad Wasat , Pandey R. K.
Published: July 2013

In Object-Oriented software development, complexity metrics help software engineers to identify the deficiencies in the design of the software system that are likely to become problem points in the subsequent phases of the SDLC, like testing and maintenance. Metrics for Component Based Software Development (CBSD) have also been proposed by the researchers. Lately the emphasis has been on metrics that are applicable during early phases of the SDLC. The XML Meta Data Interchange (XMI) standard has been implemented in most of the commercial and open source UML tools. It is now possible to automate the metrics extraction procedure right from the UML design documents. Detection of design deficiencies early in the design phase saves a lot of time and effort and results in a more maintainable design. In the present paper, we discuss the design and implementation of a metrics tool for CBSD. We have implemented component based metrics in a parserbased tool, which hereafter we refer to as CAME (Component Assembly Metrics Extraction), to calculate metrics from UML design documents. CAME is capable of generating software metrics proposed by researchers for Component Based Software Systems. We demonstrate our tool using UML component assembly diagrams for a University Case Registration System (UCRS) and its representation in UML and metrics extraction procedure.
Report on the fourth Asia-Pacific symposium on internetware (Internetware 2012)
Authors: Wang Qianxiang , Liu Lin
Published: July 2013

The Internet provides an open infrastructure for exchanging and sharing information resources among people all over the world. The rapid development and wide application of the Internet makes it a new mainstream platform for using, developing, deploying and executing software systems. In order to provide an interactive forum for researchers and professionals from related disciplines to meet and exchange ideas addressing the challenges in the Internetware setting, the Technical Committees on Software Engineering and System Software of China Computer Federation (CCF) sponsored the Asia-Pacific Symposium on Internetware series, with ACM's Cooperation. In this report, we report news from the Internetware 2012, specially the 5 keynotes and 4 regular papers that were recommended for publication in a special issue on "Internetware" of the International Journal of Software and Informatics after presented at the symposium.
POPL 2003
Authors: Bacon David F. , Cheng Perry , Rajan V. T.
Published: July 2013

Now that the use of garbage collection in languages like Java is becoming widely accepted due to the safety and software engineering benefits it provides, there is significant interest in applying garbage collection to hard real-time systems. Past approaches have generally suffered from one of two major flaws: either they were not provably real-time, or they imposed large space overheads to meet the real-time bounds. We present a mostly non-moving, dynamically defragmenting collector that overcomes both of these limitations: by avoiding copying in most cases, space requirements are kept low; and by fully incrementalizing the collector we are able to meet real-time bounds. We implemented our algorithm in the Jikes RVM and show that at real-time resolution we are able to obtain mutator utilization rates of 45% with only 1.6--2.5 times the actual space required by the application, a factor of 4 improvement in utilization over the best previously published results. Defragmentation causes no more than 4% of the traced data to be copied.
Nullspace-based stopping conditions for network-coded transmissions in DTNs
Authors: Hennessy Angela , Gladd Alex , Walker Brenton
Published: July 2013

In a challenged network environment, where end-to-end connectivity may be a rare occurrence, delay-tolerant routing protocols must strike a balance between the increased robustness and reliability that comes with message replication and the resulting high bandwidth and storage overhead. Network coded routing, in which a node combines messages from different sources, has been shown to increase reliability in the presence of link failures with small additional overhead. A drawback of network coded routing is the lack of a natural stopping condition to control the dissemination of data. We describe an enhanced coding router that uses the mathematical structure of the orthogonal complement, or nullspace, as an improved stopping condition to eliminate redundant transmissions, and an additional technique to balance multiple coded data flows. These changes are incorporated into the DTN2 Reference Implementation and evaluated in two types of experiments. In a simple data-mule scenario, our EBR router comes very close to perfect efficiency. In a more complicated scenario with segmented communities and occasional nodes moving between them, our solutions show a drastic improvement in delivery rates.