The focus of this invited keynote paper (to be presented by H. J. Siegel) is mixed-machine heterogeneous computing, where a suite of different kinds of high-performance machines are interconnected by high-speed links....
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In this paper a method is presented for copyright protection in digital images. Copyright protection is achieved by embedding an invisible signal, known as digital signature or watermark, in the digital image. The met...
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In this paper a method is presented for copyright protection in digital images. Copyright protection is achieved by embedding an invisible signal, known as digital signature or watermark, in the digital image. The method proposed in this paper casts the signature in the frequency domain by slightly modifying the values of randomly selected DC coefficients of the Discrete Cosine Transform (DCT) of the image. The same method is applied also on the Subband or Wavelet Transform coefficients. An adaptive method is proposed also based on perceptual criteria that guarantees the invisibility of the watermark and avoids the deterioration of the image. Signature detection is done via hypothesis testing, without to use any information from the original image. The watermarks embedded by the proposed method are very resistant to JPEG and other frequently used compression. Experimental results using real image data verify the effectiveness of the method.
A rate-distortion framework is used to define a verv low bit rate coding scheme based on wireframe model adaptation and optimized selection of motion estima tors. This technique achieves maximum reconstructed image qu...
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A rate-distortion framework is used to define a verv low bit rate coding scheme based on wireframe model adaptation and optimized selection of motion estima tors. This technique achieves maximum reconstructed image quality under the constraint ot a target bit rate for the coding of the motion vector field, the wireframe representation information and the prediction error. Ex-perimental results illustrating the performance of the proposed techniques in very low bit rate image sequence coding application areas are presented and evaluated.
In this paper a procedure for visualisation of videocon- ference image sequences using Virtual Reality Modeling Language (VRML) 2.0 is described. First, image sequence analysis is performed in order to estimate the sh...
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In this paper a procedure for visualisation of videocon- ference image sequences using Virtual Reality Modeling Language (VRML) 2.0 is described. First, image sequence analysis is performed in order to estimate the shape and motion parameters of the person talking in front of the camera. For this purpose, we propose the K-Means with connectivity constraint algorithm as a general segmentation algorithm combining information of various types such as colour and motion. The algo-rithm is applied "hierarchically" in the image sequence and it is first used to separate the background from the foreground object and then to further segment the foreground object into the head and shoulders regions. Based on the above information, the 3D shape parameters are estimated for each sequence and a 3D model is automatically adapted. The rigid 3D motion is estimated next for each sub-object. Finally a VRML file is created containing all the above estimated information and can be viewed using any VRML 2.0 compliant browser.
In this paper a procedure for visualisation of videoconference image sequences using Virtual Reality Modeling Language (VRML) 2.0 is described. First image sequence analysis is performed in order to estimate the shape...
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A heterogeneous computing system provides a variety of different machines, orchestrated to perform an application whose subtasks have diverse execution requirements. The subtasks must be assigned to machines (matching...
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A heterogeneous computing system provides a variety of different machines, orchestrated to perform an application whose subtasks have diverse execution requirements. The subtasks must be assigned to machines (matching) and ordered for execution (scheduling) such that the overall application execution time is minimized. A new dynamic mapping (matching and scheduling) heuristic called the hybrid remapper is presented here. The hybrid remapper is based on a centralized policy and improves a statically, obtained initial matching and scheduling by remapping to reduce the overall execution time. The remapping is non-preemptive and the execution of the hybrid remapper can be overlapped with the execution of the subtasks. During application execution, the hybrid remapper uses run-time values for the subtask completion times and machine availability times whenever possible. Therefore, the hybrid remapper bases its decisions on a mixture of run-time and expected values. The potential of the hybrid remapper to improve the performance of initial static mappings is demonstrated using simulation studies.
This paper explores the use of alternative estimates arising from the feasibility set of an optimal bounded ellipsoid (OBE) algorithm. The central estimator is interpretable as a least squares result, but all others i...
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In the recovery of failed processes in a distributed program, causal logging schemes offer several benefits. These benefits include no rollback of unfailed processes and simple approaches to output commit. Unfortunate...
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In the recovery of failed processes in a distributed program, causal logging schemes offer several benefits. These benefits include no rollback of unfailed processes and simple approaches to output commit. Unfortunately, previous approaches to the recovery of multiple simultaneous failures require that the distributed execution be blocked or that recovering processes coordinate. The latter requires assumptions which are not satisfactory. In this paper we present a solution that has neither of these drawbacks.
NASA's Mission to Planet Earth (MTPE) is planning to launch the Earth Observing System (EOS) starting in 1998. The large number of planned remote sensing satellites will bring 500 Gigabytes of information per day....
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Orthogonal subspace projection (OSP) has been successfully applied to hyperspectral image processing. In order for OSP to be effective, the number of bands must be no less than that of signatures to be classified so t...
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