8762235
A Three-Layer Virtual Director Model for Supporting Automated Multi-Site Distributed Education
In multi-site distributed education (MSDE), video streams from multiple sites are available. To best utilize the limited screen space at each site, we develop a customizable, automated display management system in this paper, i.e., only user-preferred streams will be shown as triggered by events and timers. The configuration of such user preference, however, is challenging because it has to be both human-friendly and machine-friendly. To address this challenge, we propose a three-layer virtual director model. In the user layer, we identify three categories of parameters that can represent a wide range of user preferences yet are easy to use. These preferences are then automatically translated into a machine-friendly timed automaton in the execution layer. The automaton is simulated dynamically, which selects a subset of streams to show on the screen through a display layer. Evaluation results demonstrate the correctness and efficiency of the proposed framework
677559
TEEVE: the next generation architecture for tele-immersive environments
Tele-immersive 3D multi-camera room environments are starting to emerge and with them new challenging research questions. One important question is how to organize the large amount of visual data, being captured, processed, transmitted and displayed, and their corresponding resources, over current COTS computing and networking infrastructures so that "everybody" would be able to install and use tele-immersive environments for conferencing and other activities. In this paper, we propose a novel cross-layer control and streaming framework over general purpose delivery infrastructure, called TEEVE (tele-immersive environments for everybody). TEEVE aims for effective and adaptive coordination, synchronization, and soft QoS-enabled delivery of tele-immersive visual streams to remote room(s). The TEEVE experiments between two tele-immersive rooms residing in different institutions more than 2000 miles apart show that we can sustain communication of up to 12 3D video streams with 4/spl sim/5 3D frames per second for each stream, yielding 4/spl sim/5 tele-immersive video rate.
19027501
A Study of Collaborative Dancing in Tele-immersive Environments
We first present the tele-immersive environments developed jointly by University of Illinois at Urbana-Champaign and University of California at Berkeley. The environment features 3D full and real body capturing, wide field of view, multi-display 3D rendering, and attachment free participant. We then describe a study of collaborative dancing between remotely located dancers in the shared virtual space. Two professional dancers are invited to the tele-immersive site of each university. As a preliminary experiment, we let the dancers perform elementary body movements and coordinate their dancing. The coordination requires one dancer to take the lead while the other follows her by appropriate movements. During the experiment, the dancers are dancing at various motion rates to evaluate how well the collaborative dancing is supported with the current technical boundary. Our important findings indicate that 1) tele-immersive environments have strong potential impact on the concept of choreography and communication of live dance performance, 2) the presence of multi-display system, real body 3D rendering, audio channel, and less intrusive-ness greatly enhances the immersive and dancing experience, and 3) the level of synchronization achieved by the dancers is higher than that expected from the video rate
11512625
Hourglass multimedia content and service composition framework for smart room environments
Pervasive environments with their ubiquitous multimedia devices such as video-enabled cell-phones, laptops, PC tablets, digital cameras, HDTV plasma displays are becoming integral part of our workplaces and homes. Furthermore, these digital multimedia devices make it easier and easier to create and view volumes of content that can be stored throughout the Internet. The big challenge is to organize the distributed content, get the distributed multimedia content composed, produced and distributed to users in customized fashion according to users' preference, and their resource availabilities in pervasive environments. Basically, the challenge is to create Internet Interactive Television where the user/interest group, residing in a pervasive environment, corresponds to the TV program director who decides and/or influences what content(s) will be viewed, how it will be composed, presented and delivered. In this paper, we present a vision how this challenge can be solved. We propose a novel hourglass-based system that delivers composite multimedia content to users in pervasive environments, which considers both users' interest in the content and the presentation capabilities of various display devices. This hourglass-based system relies on our content and service composition framework that allows for customized production, distribution and presentation of multimedia content for pervasive environments. We present the hourglass design, possible solutions for some content composition scenarios and validate the solutions via selected experiments.
11758
A multi-stream adaptation framework for bandwidth management in 3D tele-immersion
Tele-immersive environments will improve the state of collaboration among distributed participants. However, along with the promise a new set of challenges have emerged including the real-time acquisition, streaming and rendering of 3D scenes to convey a realistic sense of immersive spaces. Unlike 2D video conferencing, a 3D tele-immersive environment employs multiple 3D cameras to cover a much wider field of view, thus generating a very large volume of data that need to be carefully coordinated, organized, and synchronized for Internet transmission, rendering and display. This is a challenging task and a dynamic bandwidth management must be in place. To achieve this goal, we propose a multi-stream adaptation framework for bandwidth management in 3D tele-immersion. The adaptation framework relies on the hierarchy of mechanisms and services that exploits the semantic link of multiple 3D video streams in the tele-immersive environment. We implement a prototype of the framework that integrates semantic stream selection, content adaptation, and 3D data compression services with user preference. The experimental results have demonstrated that the framework shows a good quality of the resulting composite 3D rendered video in case of sufficient bandwidth, while it adapts individual 3D video streams in a coordinated and user-friendly fashion, and yields graceful quality degradation in case of low bandwidth availability.
10542337
A realtime software solution for resynchronizing filtered MPEG2 Transport stream
With the increasing demand and popularity of multimedia streaming applications over the current Internet, manipulating MPEG streams in a real-time software manner is gaining more and more importance. In this work, we studied the synchronization problem that arises when a gateway changes the data content carried in an MPEG2 Transport stream. In short, the distance between original time stamps will be changed non-uniformly when the video frames are resized, and decoders will fail to reconstruct the encoding clock from the resulting stream. We propose a cheap software real-time approach to solve this problem, which basically reuses the original time stamp packets and adapts their distance to accommodate the changes in bit rate. Experimental results from a real-time HDTV stream filter shows that our approach is correct and efficient.
15008871
Large Sample Properties of Weighted Monte Carlo Estimators
A general approach to improving simulation accuracy uses information about auxiliary control variables with known expected values to improve the estimation of unknown quantities. We analyze weighted Monte Carlo estimators that implement this idea by applying weights to independent replications. The weights are chosen to constrain the weighted averages of the control variables. We distinguish two cases (unbiased and biased), depending on whether the weighted averages of the controls are constrained to equal their expected values or some other values. In both cases, the number of constraints is usually smaller than the number of replications, so there may be many feasible weights. We select maximally uniform weights by minimizing a separable convex function of the weights subject to the control variable constraints. Estimators of this form arise (sometimes implicitly) in several settings, including at least two in finance: calibrating a model to market data (as in the work of Avellaneda et al. 2001) and calculating conditional expectations to price American options. We analyze properties of these estimators as the number of replications increases. We show that in the unbiased case, weighted Monte Carlo reduces asymptotic variance, and that all convex objective functions within a large class produce estimators that are very close to each other in a strong sense. In contrast, in the biased case the choice of objective function does matter. We show explicitly how the choice of objective determines the limit to which the estimator converges.
16993770
Service matchmaking with rough sets
With the wide adoption of open grid services architecture (OGSA) and Web services resource framework (WSRF), the grid is emerging as a service-oriented computing infrastructure for engineers and scientists to solve data and computationally intensive problems. It is envisioned that computing resources in a future grid environment will be exposed as services. Service discovery becomes an issue of vital importance for a wider uptake of the grid. This paper presents RSSM, a rough sets based service matchmaking algorithm for service discovery with an aim to tolerate uncertainty in identifying service properties. The evaluation results show that the RSSM algorithm is more effective in service discovery compared with other mechanisms such as UDDI and OWLS.
34993492
Microarray image compression: SLOCO and the effect of information loss
Microarray image technology is a powerful tool for monitoring the expression of thousands of genes simultaneously. Each microarray experiment produces immense amounts of image data, and efficient storage and transmission require compression that takes advantage of microarray image structure. In this paper we develop a compression scheme for microarray images which can be either lossless or lossy with successive refinements. Existing measures of distortion such as mean squared pixel-wise error and visual fidelity are not appropriate for microarray images. We introduce a new measure of distortion for lossy compression: the sensitivity of microarray information extraction to compression loss. Furthermore, our scheme has a coded data structure that allows fast decoding and reprocessing of image sub-blocks, and includes summary statistics and image segmentation information. The average lossless compression ratio is 1.83:1 for our cDNA test images and 2.43:1 for our inkjet test images, comparable or better than state-of-the-art lossless schemas, yet with additional structure and information. At an average lossy compression ratio of 8:1 for cDNA microarrays, we find that our scheme minimizes the effects of compression loss compared to other algorithms. We show that the variability in differential gene expression levels extracted from lossily vs. losslessly compressed microarray images is less than both the variability between different arrays and the variability between different extraction algorithms. In fact, lossy compression can improve the estimation of gene expression levels for cDNA images.
17737533
Semantic Matching of Web Services Based on Choreographies
Web services facilitate the efficient execution of B2B e-commerce by integrating business processes over the Internet, which needs dynamic and flexible binding of services. However, current Web service standards do not support it. A formal approach for semantic matching of service specifications based on choreographies, i.e., the behavior of Web services, is developed in this paper. It can accurately and automatically discover required services for integrating business processes. Firstly an extended deterministic finite state automaton (EDFA) is proposed by labeling state transitions using binary-tuples (input, output) rather than letters. The automata describe Web services in a more accurate way: the nodes represent states maintained by services; the state transitions represent communication activities of services. The automata depict the temporal sequences of communication activities that describe the behaviors of services. Further, the intersection of two EDFAs is defined. Finally, an algorithm for testing the emptiness of the languages accepted by EDFAs is presented and used to evaluate the compatibility of Web services
206807096
Multiple copy image denoising via wavelet thresholding
This work addresses the recovery of an image from noisy observations when multiple noisy copies of the image are available. The standard method is to compute the average of these copies. Since the wavelet thresholding technique has been shown to effectively denoise a single noisy copy, it is natural to consider combining these two operations of averaging and thresholding. The first important task is to find the optimal ordering. The second issue is the threshold selection for each method. By modeling the signal wavelet coefficients as Laplacian distributed and the noise as Gaussian, our investigation finds the optimal ordering to depend on the number of available copies and on the signal-to-noise ratio. We propose thresholds that are nearly optimal under the assumed model for each ordering. With the optimal and near-optimal thresholds, the two methods yield very similar performance, and both show considerable improvement over merely averaging.