bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling and visualization of leaf venation patterns
Authors: Runions Adam , Fuhrer Martin , Lane Brendan , Federl Pavol , Rolland-Lagan Anne-Gaëlle , Prusinkiewicz Przemyslaw
Published: November 2005

We introduce a class of biologically-motivated algorithms for generating leaf venation patterns. These algorithms simulate the interplay between three processes: (1) development of veins towards hormone (auxin) sources embedded in the leaf blade; (2) modification of the hormone source distribution by the proximity of veins; and (3) modification of both the vein pattern and source distribution by leaf growth. These processes are formulated in terms of iterative geometric operations on sets of points that represent vein nodes and auxin sources. In addition, a vein connection graph is maintained to determine vein widths. The effective implementation of the algorithms relies on the use of space subdivision (Voronoi diagrams) and time coherence between iteration steps. Depending on the specification details and parameters used, the algorithms can simulate many types of venation patterns, both open (tree-like) and closed (with loops). Applications of the presented algorithms include texture and detailed structure generation for image synthesis purposes, and modeling of morphogenetic processes in support of biological research.
High performance imaging using large camera arrays
Authors: Wilburn Bennett , Joshi Neel , Vaish Vaibhav , Talvala Eino-Ville , Antunez Emilio , Barth Adam , Adams Andrew , Horowitz Mark , Levoy Marc
Published: November 2005

The advent of inexpensive digital image sensors and the ability to create photographs that combine information from a number of sensed images are changing the way we think about photography. In this paper, we describe a unique array of 100 custom video cameras that we have built, and we summarize our experiences using this array in a range of imaging applications. Our goal was to explore the capabilities of a system that would be inexpensive to produce in the future. With this in mind, we used simple cameras, lenses, and mountings, and we assumed that processing large numbers of images would eventually be easy and cheap. The applications we have explored include approximating a conventional single center of projection video camera with high performance along one or more axes, such as resolution, dynamic range, frame rate, and/or large aperture, and using multiple cameras to approximate a video camera with a large synthetic aperture. This permits us to capture a video light field, to which we can apply spatiotemporal view interpolation algorithms in order to digitally simulate time dilation and camera motion. It also permits us to create video sequences using custom non-uniform synthetic apertures.
Acquisition of time-varying participating media
Authors: Hawkins Tim , Einarsson Per , Debevec Paul
Published: November 2005

We present a technique for capturing time-varying volumetric data of participating media. A laser sheet is swept repeatedly through the volume, and the scattered light is imaged using a high-speed camera. Each sweep of the laser provides a near-simultaneous volume of density values. We demonstrate rendered animations under changing viewpoint and illumination, making use of measured values for the scattering phase function and albedo.
Modeling hair from multiple views
Authors: Wei Yichen , Ofek Eyal , Quan Long , Shum Heung-Yeung
Published: November 2005

In this paper, we propose a novel image-based approach to model hair geometry from images taken at multiple viewpoints. Unlike previous hair modeling techniques that require intensive user interactions or rely on special capturing setup under controlled illumination conditions, we use a handheld camera to capture hair images under uncontrolled illumination conditions. Our multi-view approach is natural and flexible for capturing. It also provides inherent strong and accurate geometric constraints to recover hair models.In our approach, the hair fibers are synthesized from local image orientations. Each synthesized fiber segment is validated and optimally triangulated from all visible views. The hair volume and the visibility of synthesized fibers can also be reliably estimated from multiple views. Flexibility of acquisition, little user interaction, and high quality results of recovered complex hair models are the key advantages of our method.
Animating pictures with stochastic motion textures
Authors: Chuang Yung-Yu , Goldman Dan B , Zheng Ke Colin , Curless Brian , Salesin David H. , Szeliski Richard
Published: November 2005

In this paper, we explore the problem of enhancing still pictures with subtly animated motions. We limit our domain to scenes containing passive elements that respond to natural forces in some fashion. We use a semi-automatic approach, in which a human user segments the scene into a series of layers to be individually animated. Then, a "stochastic motion texture" is automatically synthesized using a spectral method, i.e., the inverse Fourier transform of a filtered noise spectrum. The motion texture is a time-varying 2D displacement map, which is applied to each layer. The resulting warped layers are then recomposited to form the animated frames. The result is a looping video texture created from a single still image, which has the advantages of being more controllable and of generally higher image quality and resolution than a video texture created from a video source. We demonstrate the technique on a variety of photographs and paintings.
Image completion with structure propagation
Authors: Sun Jian , Yuan Lu , Jia Jiaya , Shum Heung-Yeung
Published: November 2005

In this paper, we introduce a novel approach to image completion, which we call structure propagation. In our system, the user manually specifies important missing structure information by extending a few curves or line segments from the known to the unknown regions. Our approach synthesizes image patches along these user-specified curves in the unknown region using patches selected around the curves in the known region. Structure propagation is formulated as a global optimization problem by enforcing structure and consistency constraints. If only a single curve is specified, structure propagation is solved using Dynamic Programming. When multiple intersecting curves are specified, we adopt the Belief Propagation algorithm to find the optimal patches. After completing structure propagation, we fill in the remaining unknown regions using patch-based texture synthesis. We show that our approach works well on a number of examples that are challenging to state-of-the-art techniques.
Far voxels
Authors: Gobbetti Enrico , Marton Fabio
Published: November 2005

We present an efficient approach for end-to-end out-of-core construction and interactive inspection of very large arbitrary surface models. The method tightly integrates visibility culling and out-of-core data management with a level-of-detail framework. At preprocessing time, we generate a coarse volume hierarchy by binary space partitioning the input triangle soup. Leaf nodes partition the original data into chunks of a fixed maximum number of triangles, while inner nodes are discretized into a fixed number of cubical voxels. Each voxel contains a compact direction dependent approximation of the appearance of the associated volumetric subpart of the model when viewed from a distance. The approximation is constructed by a visibility aware algorithm that fits parametric shaders to samples obtained by casting rays against the full resolution dataset. At rendering time, the volumetric structure, maintained off-core, is refined and rendered in front-to-back order, exploiting vertex programs for GPU evaluation of view-dependent voxel representations, hardware occlusion queries for culling occluded subtrees, and asynchronous I/O for detecting and avoiding data access latencies. Since the granularity of the multiresolution structure is coarse, data management, traversal and occlusion culling cost is amortized over many graphics primitives. The efficiency and generality of the approach is demonstrated with the interactive rendering of extremely complex heterogeneous surface models on current commodity graphics platforms.
Cache-oblivious mesh layouts
Authors: Yoon Sung-Eui , Lindstrom Peter , Pascucci Valerio , Manocha Dinesh
Published: November 2005

We present a novel method for computing cache-oblivious layouts of large meshes that improve the performance of interactive visualization and geometric processing algorithms. Given that the mesh is accessed in a reasonably coherent manner, we assume no particular data access patterns or cache parameters of the memory hierarchy involved in the computation. Furthermore, our formulation extends directly to computing layouts of multi-resolution and bounding volume hierarchies of large meshes.We develop a simple and practical cache-oblivious metric for estimating cache misses. Computing a coherent mesh layout is reduced to a combinatorial optimization problem. We designed and implemented an out-of-core multilevel minimization algorithm and tested its performance on unstructured meshes composed of tens to hundreds of millions of triangles. Our layouts can significantly reduce the number of cache misses. We have observed 2--20 times speedups in view-dependent rendering, collision detection, and isocontour extraction without any modification of the algorithms or runtime applications.
The VarrierTMautostereoscopic virtual reality display
Authors: Sandin Daniel J. , Margolis Todd , Ge Jinghua , Girado Javier , Peterka Tom , DeFanti Thomas A.
Published: November 2005

Virtual reality (VR) has long been hampered by the gear needed to make the experience possible; specifically, stereo glasses and tracking devices. Autostereoscopic display devices are gaining popularity by freeing the user from stereo glasses, however few qualify as VR displays. The Electronic Visualization Laboratory (EVL) at the University of Illinois at Chicago (UIC) has designed and produced a large scale, high resolution head-tracked barrier-strip autostereoscopic display system that produces a VR immersive experience without requiring the user to wear any encumbrances. The resulting system, called Varrier, is a passive parallax barrier 35-panel tiled display that produces a wide field of view, head-tracked VR experience. This paper presents background material related to parallax barrier autostereoscopy, provides system configuration and construction details, examines Varrier interleaving algorithms used to produce the stereo images, introduces calibration and testing, and discusses the camera-based tracking subsystem.
Water drops on surfaces
Authors: Wang Huamin , Mucha Peter J. , Turk Greg
Published: November 2005

We present a physically-based method to enforce contact angles at the intersection of fluid free surfaces and solid objects, allowing us to simulate a variety of small-scale fluid phenomena including water drops on surfaces. The heart of this technique is a
virtual surface
method, which modifies the level set distance field representing the fluid surface in order to maintain an appropriate contact angle. The surface tension that is calculated on the contact line between the solid surface and liquid surface can then capture all interfacial tensions, including liquid-solid, liquid-air and solid-air tensions. We use a simple dynamic contact angle model to select contact angles according to the solid material property, water history, and the fluid front's motion. Our algorithm robustly and accurately treats various drop shape deformations, and handles both flat and curved solid surfaces. Our results show that our algorithm is capable of realistically simulating several small-scale liquid phenomena such as beading and flattened drops, stretched and separating drops, suspended drops on curved surfaces, and capillary action.
CrossY
Authors: Apitz Georg , Guimbretière François
Published: November 2005

We introduce CrossY, a simple drawing application developed as a benchmark to demonstrate the feasibility of goal-crossing as the basis for a graphical user interface. While crossing was previously identified as a potential substitute for the classic point-and-click interaction, this work is the first to report on the practical aspects of implementing an interface solely based on goal-crossing.
Multi-finger gestural interaction with 3D volumetric displays
Authors: Grossman Tovi , Wigdor Daniel , Balakrishnan Ravin
Published: November 2005

Volumetric displays provide interesting opportunities and challenges for 3D interaction and visualization, particularly when used in a highly interactive manner. We explore this area through the design and implementation of techniques for interactive direct manipulation of objects with a 3D volumetric display. Motion tracking of the user's fingers provides for direct gestural interaction with the virtual objects, through manipulations on and around the display's hemispheric enclosure. Our techniques leverage the unique features of volumetric displays, including a 360° viewing volume that enables manipulation from any viewpoint around the display, as well as natural and accurate perception of true depth information in the displayed 3D scene. We demonstrate our techniques within a prototype 3D geometric model building application.
Sketching mesh deformations
Authors: Kho Youngihn , Garland Michael
Published: November 2005

Techniques for interactive deformation of unstructured polygon meshes are of fundamental importance to a host of applications. Most traditional approaches to this problem have emphasized precise control over the deformation being made. However, they are often cumbersome and unintuitive for non-expert users.In this paper, we present an interactive system for deforming unstructured polygon meshes that is very easy to use. The user interacts with the system by sketching curves in the image plane. A single stroke can define a free-form skeleton and the region of the model to be deformed. By sketching the desired deformation of this reference curve, the user can implicitly and intuitively control the deformation of an entire region of the surface. At the same time, the reference curve also provides a basis for controlling additional parameters, such as twist and scaling. We demonstrate that our system can be used to interactively edit a variety of unstructured mesh models with very little effort. Furthermore, we can also use our formulation of the deformation to achieve a natural interpolation between character poses, thus producing simple key framed animations.
Adaptive dynamics of articulated bodies
Authors: Redon Stephane , Galoppo Nico , Lin Ming C.
Published: November 2005

Forward dynamics is central to physically-based simulation and control of articulated bodies. We present an adaptive algorithm for computing forward dynamics of articulated bodies: using novel motion error metrics, our algorithm can automatically simplify the dynamics of a multi-body system, based on the desired number of degrees of freedom and the location of external forces and active joint forces. We demonstrate this method in plausible animation of articulated bodies, including a large-scale simulation of 200 animated humanoids and multi-body dynamics systems with many degrees of freedom. The graceful simplification allows us to achieve up to two orders of magnitude performance improvement in several complex benchmarks.
Real-Time subspace integration for St. Venant-Kirchhoff deformable models
Authors: Barbič Jernej , James Doug L.
Published: November 2005

In this paper, we present an approach for fast subspace integration of reduced-coordinate nonlinear deformable models that is suitable for interactive applications in computer graphics and haptics. Our approach exploits dimensional model reduction to build reduced-coordinate deformable models for objects with complex geometry. We exploit the fact that model reduction on large deformation models with
linear
materials (as commonly used in graphics) result in internal force models that are simply cubic polynomials in reduced coordinates. Coefficients of these polynomials can be precomputed, for efficient runtime evaluation. This allows simulation of nonlinear dynamics using fast implicit Newmark subspace integrators, with subspace integration costs independent of geometric complexity. We present two useful approaches for generating low-dimensional subspace bases: modal derivatives and an interactive sketching technique. Mass-scaled principal component analysis (mass-PCA) is suggested for dimensionality reduction. Finally, several examples are given from computer animation to illustrate high performance, including force-feedback haptic rendering of a complicated object undergoing large deformations.
Blister
Authors: Hable John , Rossignac Jarek
Published: November 2005

By combining depth peeling with a linear formulation of a Boolean expression called Blist, the Blister algorithm renders an arbitrary CSG model of n primitives in at most k steps, where k is the number of depth-layers in the arrangement of the primitives. Each step starts by rendering each primitive to produce candidate surfels on the next depth-layer. Then, it renders the primitives again, one at a time, to classify the candidate surfels against the primitive and to evaluate the Boolean expression directly on the GPU. Since Blist does not expand the CSG expression into a disjunctive (sum-of-products) form, Blister has O(kn) time complexity. We explain the Blist formulation while providing algorithms for CSG-to-Blist conversion and Blist-based parallel surfel classification. We report real-time performance for nontrivial CSG models. On hardware with an 8-bit stencil buffer, we can render all possible CSG expressions with 3909 primitives.
Light diffusion in multi-layered translucent materials
Authors: Donner Craig , Jensen Henrik Wann
Published: November 2005

This paper introduces a shading model for light diffusion in multi-layered translucent materials. Previous work on diffusion in translucent materials has assumed smooth semi-infinite homogeneous materials and solved for the scattering of light using a dipole diffusion approximation. This approximation breaks down in the case of thin translucent slabs and multi-layered materials. We present a new efficient technique based on multiple dipoles to account for diffusion in thin slabs. We enhance this multipole theory to account for mismatching indices of refraction at the top and bottom of of translucent slabs, and to model the effects of rough surfaces. To model multiple layers, we extend this single slab theory by convolving the diffusion profiles of the individual slabs. We account for multiple scattering between slabs by using a variant of Kubelka-Munk theory in frequency space. Our results demonstrate diffusion of light in thin slabs and multi-layered materials such as paint, paper, and human skin.
As-rigid-as-possible shape manipulation
Authors: Igarashi Takeo , Moscovich Tomer , Hughes John F.
Published: November 2005

We present an interactive system that lets a user move and deform a two-dimensional shape without manually establishing a skeleton or freeform deformation (FFD) domain beforehand. The shape is represented by a triangle mesh and the user moves several vertices of the mesh as constrained handles. The system then computes the positions of the remaining free vertices by minimizing the distortion of each triangle. While physically based simulation or iterative refinement can also be used for this purpose, they tend to be slow. We present a two-step closed-form algorithm that achieves real-time interaction. The first step finds an appropriate rotation for each triangle and the second step adjusts its scale. The key idea is to use quadratic error metrics so that each minimization problem becomes a system of linear equations. After solving the simultaneous equations at the beginning of interaction, we can quickly find the positions of free vertices during interactive manipulation. Our approach successfully conveys a sense of rigidity of the shape, which is difficult in space-warp approaches. With a multiple-point input device, even beginners can easily move, rotate, and deform shapes at will.
Soft shadow volumes for ray tracing
Authors: Laine Samuli , Aila Timo , Assarsson Ulf , Lehtinen Jaakko , Akenine-Möller Tomas
Published: November 2005

We present a new, fast algorithm for rendering physically-based soft shadows in ray tracing-based renderers. Our method replaces the hundreds of shadow rays commonly used in stochastic ray tracers with a single shadow ray and a local reconstruction of the visibility function. Compared to tracing the shadow rays. our algorithm produces exactly the same image while executing one to two orders of magnitude faster in the test scenes used. Our first contribution is a two-stage method for quickly determining the silhouette edges that overlap an area light source, as seen from the point to be shaded. Secondly, we show that these partial silhouettes of occluders, along with a single shadow ray, are sufficient for reconstructing the visibility function between the point and the light source.
Precomputed local radiance transfer for real-time lighting design
Authors: Kristensen Anders Wang , Akenine-Möller Tomas , Jensen Henrik Wann
Published: November 2005

This paper introduces a new method for real-time relighting of scenes illuminated by local light sources. We extend previous work on precomputed radiance transfer for distant lighting to local lighting by introducing the concept of unstructured light clouds. The unstructured light cloud enables a compact representation of local lights in the model and real-time rendering of complex models with full global illumination due to local light sources. We use simplification of lights, and clustered PCA to obtain a compressed representation. When storing only the indirect component of the illumination, we are able to get high quality with only 8-16 lighting coefficients per vertex. Our results demonstrate real-time rendering of scenes with moving lights, dynamic cameras, glossy materials and global illumination.
Local, deformable precomputed radiance transfer
Authors: Sloan Peter-Pike , Luna Ben , Snyder John
Published: November 2005

Precomputed radiance transfer (PRT) captures realistic lighting effects from distant, low-frequency environmental lighting but has been limited to static models or precomputed sequences. We focus on PRT for local effects such as bumps, wrinkles, or other detailed features, but extend it to arbitrarily deformable models. Our approach applies zonal harmonics (ZH) which approximate spherical functions as sums of circularly symmetric Legendre polynomials around different axes. By spatially varying both the axes and coefficients of these basis functions, we can fit to spatially varying transfer signals. Compared to the spherical harmonic (SH) basis, the ZH basis yields a more compact approximation. More important, it can be trivially rotated whereas SH rotation is expensive and unsuited for dense per-vertex or per-pixel evaluation. This property allows, for the first time, PRT to be mapped onto deforming models which re-orient the local coordinate frame. We generate ZH transfer models by fitting to PRT signals simulated on meshes or simple parametric models for thin membranes and wrinkles. We show how shading with ZH transfer can be significantly accelerated by specializing to a given lighting environment. Finally, we demonstrate real-time rendering results with soft shadows, inter-reflections, and subsurface scatter on deforming models.
Efficient end to end data exchange using configurable compression
Authors: Wiseman Yair , Schwan Karsten , Widener Patrick
Published: November 2005

We explore the use of compression methods to improve the middleware-based exchange of information in interactive or collaborative distributed applications. In such applications, good compression factors must be accompanied by compression speeds suitable for the data transfer rates sustainable across network links. Our approach combines methods that continuously monitor current network and processor resources and assess compression effectiveness, with techniques that automatically choose suitable compression techniques. By integrating these techniques into middleware, there is little need for end user involvement, other than expressing the target rates of data transmission. The resulting network- and user-aware compression methods are evaluated experimentally across a range of network links and application data, the former ranging from low end links to homes, to wide-area Internet links, to high end links in intranets, the latter including both scientific (binary molecular dynamics data) and commercial (XML) data sets. Results attained demonstrate substantial improvements of this adaptive technique for data compression over non-adaptive approaches, where better compression methods are used when CPU loads are low and/or network links are slow, and where less effective and typically, faster compression techniques are used in high end network infrastructures.
A policy flexible architecture for secure operating system
Authors: Lin Zhiqiang , Wang Chao , Mao Bing , Xie Li
Published: November 2005

As the fundamental software to guarantee information security, operating system is desired to support various security policies flexibly and to control the propagation and revocation of access rights efficiently. This paper presents a design and implementation of Policy Flexible Architecture (PFA) for secure operating system to achieve the coordination, extensibility, consistency and dynamic configuration of security policies. Through a thorough analysis of all related facilities, PFA classifies policy constructions into several levels according to their effects on security status; PFA emphasizes on centralized management of security policy as well as on centralized maintainability of security attributes; for the first time PFA gives revocation rules to specify how and when to revoke permissions. PFA has been applied to our Secure Enhanced Linux Operating System, and the experiment shows that the system holds at least three advantages. First, it helps users to choose intended security policies flexibly. Besides it supports users to add new security policies according to specific security requirements easily. Finally it sets permission revocations immediately and gets no significant performance penalty.
An example of communication between security tools
Authors: Guerrero Jorge Herrerías , Cárdenas Roberto Gómez
Published: November 2005

Two of the most used tools in the area of computer security are the firewalls and the Intrusion Detection Systems. Both of them fulfill the task for which they were designed for but unfortunately their response to an attack can be limited. The communication of both tools increases the response capacity of the system, but we need a protocol to communicate them. In this paper we present how is to communicate two security tools: snort and Iptables. The communication is based on the Intrusion Detection Message Exchange Format (IDMEF) proposed by the Intrusion Detection Working Group (IDWG).
The research on consistency of space/time of IDS
Authors: Luo Guangchun , Lu Xianliang , Yang Ting
Published: November 2005

A method of Intrude Detection based on Data Fusion is introduced and a new mechanism -- DFIDM has been presented in the paper. We focus in consistency of Space/Time during data collecting and object collecting. Multisensor will collect data such as log file, information of Network Traffics and data packets of network based on this mechanism. First, these data will be sent to local decision-maker to be judged, and then calibrated after Data collecting and object collecting period. At last, it will be transferred to the fusion center for decision-making. As result of the experiment shown in the paper, the mechanism can improve the performance of IDS.
The design and implementation of LilyTask in shared memory
Authors: Tang Yan , Wang Tao , Li Xiaoming
Published: November 2005

Constructing high performance computing system and providing easy-to-use programming model for users are two main parts of parallel computing, but the latter has been in a sorry state for a long time. LilyTask programming model is based on tasks which can be easily mapped to the decomposition of computation. Without explict synchronization and mutual exclusion, users will concentrate on the inherent parallelism in a problem instead of lock/unlock programming techniques. Most existing implementations of the task pool, a flexible data structure for task parallel, lack basic representation of relations among tasks. LilyTask introduces task group and task relation to help users easily map subproblems to tasks. The kernel of LilyTask system, a distributed task pool, automatically exploits potential parallelism among tasks at runtime. With runtime task assignment and task stealing, LilyTask system achieves dynamic load balancing. Our performance evaluation shows that LilyTask system with task pool outperforms sequential programs and BSPlib in solving both regular and irregular problems.
A Word from the Editor
Authors: Lee Newton
Published: November 2005

In this special issue on games and pervasive gaming, the Interviews column features video interviews with two of our distinguished advisory board members, Ken Goldstein (May 16, 2005) and Seamus Blackley (May 13, 2005).
Interview with Seamus Blackley
Authors: Lee Newton , Blackley Seamus
Published: November 2005

Seamus Blackley is an agent at Creative Artists Agency (CAA). Prior to CAA, Seamus joined Microsoft in 1999 and piloted the creation of the Xbox game platform. After Microsoft, Blackley and a group of his Xbox business partners launched Capital Entertainment Group. In the video interview, you will hear Seamus' answers to the following questions:1. You are the co-creator of the Xbox. How did you come up with the Xbox idea and what did you do to make it a reality?2. What do you think about the new Xbox 360 that is both a gaming console and a digital entertainment hub?3. What role does the Creative Artists Agency play in the computer gaming industry?4. How do you encourage game publishers and developers to create more original and more creative games?5. How do you manage the financial risk of producing a high-budget game in the highly competitive gaming market?6. How important is the multiplayer online component for a successful game?7. Combining video games and physical fitness is a form of "exergaming." What other types of gaming do you envision we will have in the future?8. What will take computer games to the next new level?
The Drop
Authors: Smith Ian , Consolvo Sunny , LaMarca Anthony
Published: November 2005

We are developing a new multiplayer pervasive game, called The Drop, designed to be compelling to play and yet practical to deploy in real-world settings. In The Drop, two teams use mobile phones to play a version of "capture the flag," where one team hides a virtual "briefcase" in a public place and the other team attempts to find it within a specified amount of time. If the team that is searching for the briefcase finds it within the game's time limit, they win; otherwise, the team that hid the briefcase wins. In this article we explain how the game is played, then discuss the technical, social, and business challenges we have faced while creating and implementing it.
Albert in Africa
Authors: Newman Ken
Published: November 2005

RPGs (role playing games) and improvisational theatre have some obvious similarities. Both require the participants to work together in real-time to construct dynamic narrative elements. Seeing communication in terms of ongoing narrative contracts is a well-accepted principle of improvisational theatre [Johnstone 1981]. The recipient of the offer can either accept the offer, block it, or a make counter-offer; and good improvisational theatre's golden rule is "never block an offer." This article describes a study of subjects engaged in a controlled online role-playing "encounter." The encounter is entitled "Albert in Africa;" the study draws on the previously described fun unification model [Newman 2004]. In this article, subjects' individual predispositions and responses are correlated with the number of acceptances, blocks, and counter-offers they made during their encounter. From this emerges a view of the complex interactions that make up the simple universal construct of fun in an RPG environment and the identification of certain combinations of predisposition and "environmental affordances" which act as predictors of the subjects' fun response.
Sports over a distance
Authors: Mueller Florian 'Floyd' , Agamanolis Stefan
Published: November 2005

Computer games lack the social bonding and collective physical exercise benefits that sports provide. To overcome these limitations, we have been investigating how to apply the benefits of sport, in particular the workout and social bonding effect, in a distributed setting. We designed, developed, and evaluated Breakout for Two, which allows people who are miles apart to play a physically exhausting ball game together. We had over a thousand players who interacted through a life-size video-conference screen using a regular soccer ball as an input device. In an evaluative study, 56 players were interviewed and said that they got to know the other player better, had more fun, became better friends, and were happier with the transmitted audio and video quality in comparison to those who played the same game using a nonexertion keyboard interface. These results suggest that sports over a distance is an exciting new field with an "exertion interface" that encourages remote interaction, where players can achieve both a work-out and socializing.
Welcome to China's first multimedia conference
Authors: Hylton Eldon C.
Published: November 2005

China is experiencing a Cultural Renaissance juxtaposed between the Middle Kingdom's historical cultural heritage, digital technologies and techniques, coupled with the uniqueness of China 's contemporary creative spirit.The multimedia industry in China is navigating towards a horizon of individually created products and services that will be in-demand domestically and worldwide. The importance of China's multimedia industry is supported by governmental policies, and complemented with academic vision from the science, technology, and art communities of various colleges and universities throughout China. The underpinnings of collaboration for China's multimedia industry are forming. Intellectual property rights are of paramount importance to the industry, as well as the enforcement of copyright laws to protect the economic value created by this creative spirit. The success of the multimedia industry in China will depend on individuals and companies creating new technologies and products and competing not only in China 's domestic marketplace, but worldwide.On behalf of BMIA, the Hosts, and Sponsors, we welcome you to China 's First Multimedia Conference: MMEC 2005
The NVIDIA® championships at QuakeCon 2005
Authors: Lee Newton
Published: November 2005

Tournament line up includes a little old school, a little new school, and $150,000 in cashMESQUITE, Texas -- June 10, 2005 -- The NVIDIA Championships at QuakeCon will take on a slightly different flavor in 2005, with new tournaments for gamers to show off their skills as part the 10th annual QuakeCon, the largest four day gaming festival in North America. The Gaylord Texan Resort and Convention Center in Grapevine, Texas will be ground zero for more than 6,000 rabid gamers, all with the chance to compete for $150,000 in cash courtesy of title sponsor NVIDIA, the worldwide leader in graphics processing.
2nd IEEE International Workshop on Networking Issues in Multimedia Entertainment (NIME'06)
Authors: Lee Newton
Published: November 2005

The growing availability of digital contents and the simultaneous cost reductions in storage, processing, and networking is driving the growth of the entertainment technology. While in the past entertainment technology traditionally offered predominantly passive experiences, continual advances in network and computer technologies are providing tools for implementing greater interactivity and for enabling consumers to enjoy more exciting experiences, such as, for example, interactive digital TV, interactive theatre and orchestrated music and sound design. This phenomenon is pulling together an extremely diverse group of experts specializing in different technical areas, such as networking, computer graphics, artificial intelligence, games, animation, multimedia design, human-computer interaction, educational media and software engineering. Even though high-tech entertainment promotes interdisciplinary fusion, yet only the ubiquity of wireless/wired communication is considered suitable for accepting the challenge of building a large interactive environment for the delivery of the maximum entertainment value to millions of consumers worldwide. In this respect, there is a great hope that the wired and wireless may take over this complex scenario for fulfilling the consumer expectations. The second IEEE International Workshop on Networking Issues in Multimedia Entertainment provides an open forum for researchers, engineers and academia to exchange the latest technical information and research findings on next-generation networked multimedia concepts, technologies, systems, and applications for entertainment covering existing deployments, current developments and future evolution.
Women's Game Conference 2005
Authors: Lee Newton
Published: November 2005

The Game Initiative's Women's Game Conference focuses on women in the computer and video game industry. The conference program includes career paths for women in the industry, gender inclusive game design and women and girls as consumers of games.The 2005 Women's Game Conference takes place October 26-27, 2005 - the day before and the first day of - the Austin Game Conference at the Austin Convention Center and is open to anyone interested in the game industry and game development.2005 topics include identifying the female game player market, representation of women in advertising, importance of art for female players, consumer trends of female players, games for girls, recruiting and mentoring of women in the game industry and quality of life concerns, and many other timely topics.
Navigation protocols in sensor networks
Authors: Li Qun , Rus Daniela
Published: November 2005

We develop distributed algorithms for adaptive sensor networks that respond to directing a target through a region of space. We model this problem as an online distributed motion planning problem. Each sensor node senses values in its perception space and has the ability to trigger exceptions events we call “danger” and model as “obstacles”. The danger/obstacle landscape changes over time. We present algorithms for computing distributed maps in perception space and for using these maps to compute adaptive paths for a mobile node that can interact with the sensor network. We give the analysis to the protocol and report on hardware experiments using a physical sensor network consisting of Mote sensors. We also show how to reduce searching space and communication cost using Voronoi diagram.
Integrated coverage and connectivity configuration for energy conservation in sensor networks
Authors: Xing Guoliang , Wang Xiaorui , Zhang Yuanfang , Lu Chenyang , Pless Robert , Gill Christopher
Published: November 2005

An effective approach for energy conservation in wireless sensor networks is scheduling sleep intervals for extraneous nodes while the remaining nodes stay active to provide continuous service. For the sensor network to operate successfully, the active nodes must maintain both sensing coverage and network connectivity. Furthermore, the network must be able to configure itself to any feasible degree of coverage and connectivity in order to support different applications and environments with diverse requirements. This article presents the design and analysis of novel protocols that can dynamically configure a network to achieve guaranteed degrees of coverage and connectivity. This work differs from existing connectivity or coverage maintenance protocols in several key ways. (1) We present a Coverage Configuration Protocol (CCP) that can provide different degrees of coverage requested by applications. This flexibility allows the network to self-configure for a wide range of applications and (possibly dynamic) environments. (2) We provide a geometric analysis of the relationship between coverage and connectivity. This analysis yields key insights for treating coverage and connectivity within a unified framework; in sharp contrast to several existing approaches that address the two problems in isolation. (3) We integrate CCP with SPAN to provide both coverage and connectivity guarantees. (4) We propose a probabilistic coverage model and extend CCP to provide probabilistic coverage guarantees. We demonstrate the capability of our protocols to provide guaranteed coverage and connectivity configurations through both geometric analysis and extensive simulations.
A framework for time indexing in sensor networks
Authors: He Guanghui , Zheng Rong , Gupta Indranil , Sha Lui
Published: November 2005

In this article, we define the
time-indexing
problem as the in-network storage and querying of sensor network data based solely on the time attribute. We argue qualitatively why existing storage schemes may be insufficient as solutions. We then present, analyze, and evaluate novel and lightweight solutions to both the storage and the querying subproblems for time indexing. First, the time-indexed storage problem is formally defined and two formulations are presented seeking to optimize generic utility functions that are derived from concerns about energy, bandwidth usage, and storage balancing. We present and analyze decentralized protocols to solve these formulations and prove the optimality of some of our solutions. Secondly, maintenance and use of simple overlays among rendezvous point nodes in order to enable fault-tolerant and efficient time-indexed queries are discussed. Finally, simulation results are presented to quantify performance characteristics of the protocols, and we find that our proposed scheme has low query overhead that scales with system size and density while exhibiting very good load-balancing and fault-tolerance properties. The use of time-indexed structure is shown to achieve more than double the lifetime of sensor networks compared to existing approaches in some scenarios.
A kernel-based learning approach to ad hoc sensor network localization
Authors: Nguyen Xuanlong , Jordan Michael I. , Sinopoli Bruno
Published: November 2005

We show that the coarse-grained and fine-grained localization problems for ad hoc sensor networks can be posed and solved as a pattern recognition problem using kernel methods from statistical learning theory. This stems from an observation that the kernel function, which is a similarity measure critical to the effectiveness of a kernel-based learning algorithm, can be naturally defined in terms of the matrix of signal strengths received by the sensors. Thus we work in the natural coordinate system provided by the physical devices. This not only allows us to sidestep the difficult ranging procedure required by many existing localization algorithms in the literature, but also enables us to derive a simple and effective localization algorithm. The algorithm is particularly suitable for networks with densely distributed sensors, most of whose locations are unknown. The computations are initially performed at the base sensors, and the computation cost depends only on the number of base sensors. The localization step for each sensor of unknown location is then performed locally in linear time. We present an analysis of the localization error bounds, and provide an evaluation of our algorithm on both simulated and real sensor networks.
Distance Perception and the Visual Horizon in Head-Mounted Displays
Authors: Messing Ross , Durgin Frank H.
Published: November 2005

Can distance perception be studied using virtual reality (VR) if distances are systematically underestimated in VR head-mounted displays (HMDs)? In an experiment in which a real environment was observed through an HMD, via live video, distances, as measured by visually directed walking, were underestimated even when the perceived environment was known to be real and present. However, the underestimation was linear, which means that higher-order space perception effects might be preserved in VR. This is illustrated in a second experiment, in which the visual horizon was artificially manipulated in a simulated outdoor field presented in immersive VR. As predicted by the claim that angle of declination from the horizon may serve as a strong cue to distance, lowering the horizon line produced “expansiv ” judgments of distance (power function exponents greater than one) both in verbal and in motor estimates.
Toward Perceptually Realistic Talking Heads: Models, Methods, and McGurk
Authors: Cosker Darren , Paddock Susan , Marshall David , Rosin Paul L. , Rushton Simon
Published: November 2005

Motivated by the need for an informative, unbiased, and quantitative perceptual method for the evaluation of a talking head we are developing, we propose a new test based on the “McGurk Effect.” Our approach helps to identify strengths and weaknesses in visual--speech synthesis algorithms for talking heads and facial animations, in general, and uses this insight to guide further development. We also evaluate the
behavioral
quality of our facial animations in comparison to real-speaker footage and demonstrate our tests by applying them to our current speech-driven facial animation system.
Collisions and Attention
Authors: O'Sullivan Carol
Published: November 2005

Attention is an important factor in the perception of static and dynamic scenes, which should, therefore, be taken into account when creating graphical images and animation. Recently, researchers have recognized this fact and have been investigating how the focus of attention can be measured, predicted, and exploited in graphical systems. In this article, we explore some preliminary strategies for developing an automatic means of predicting and exploiting attention in the processing of collisions and other dynamic events. Recent work on the perception of causality has shown that attention can change the way in which a dynamic scene consisting of collision events is perceived. We describe a series of experiments designed to determine the source of biases in the perception of anomalous collision dynamics and, in particular, whether attention plays a role. Using an eye-tracker, eye-movements were recorded while participants viewed animations of simple causal launching events in 3D involving two colliding spheres. Results indicated that there was indeed a definite pattern to the allocation of attention based on the nature of the event, which is promising for the goal of developing a predictive metric. As a follow-up, a paper-based experiment was carried out in which participants were asked to sketch the predicted post-collision trajectories of the same two spheres printed on paper. These experiments demonstrated that attention alone was not sufficient in determining performance, but rather the
nature
of the dynamic event itself also played a role.