17692093
Life after Video Coding Standards: Rate Shaping and Error Concealment
Is there life after video coding standards? One might think that research has no room to advance with the video coding standards already defined. On the contrary, exciting research opportunities arise after the standards are specified. In this paper, we introduce two standard-related research areas: rate shaping and error concealment, as examples of interesting research that finds its context in standards. Experiment results are also shown.
418775
Progressive image watermarking
Progressive transmission of images is very useful in many applications, especially in image transmission over the Internet. To view an image, people would want to see part of the image while the image transmission is in progress, rather than having to wait until the end of the image transmission. On the other hand, the ease of transmission and copying of images creates the need to use digital watermarking to embed the copyright information seamlessly into the media. We propose a progressive image watermarking scheme. In this scheme, the watermark is embedded in such a way that we can retrieve part of it even when the watermarked image is still being transmitted. As transmission progresses, the retrieved watermark has a decreasing bit error rate. Our proposed methods not only transmit the watermarked image progressively, but also intelligently select watermark embedding locations robust to various attacks.
9048292
Updating mixture of principal components for error concealment
We present a new statistical modeling technique called "updating mixture of principal components" (UMPC). UMPC specifically captures the non-stationary as well as the multi-modal characteristics of the data. Real-world data such as video data typically have these two characteristics. The video content changes over time and has a multi-modal probability distribution. We apply UMPC to perform error concealment for video data transmitted over networks with losses, and show that UMPC outperforms conventional error concealment methods.
18749157
A case study in genome-level fragment assembly
MOTIVATION
We use the fact of two teams independently sequencing the one megabase genome of Borrelia burgdorferi as an opportunity to study the accuracy of genome-level assembly.


RESULTS
We compare the results of three different assembly programs (PHRAP, TIGR Assembler, and STROLL) on the DNA fragments used in both the Brookhaven and TIGR sequencing projects. We also describe the algorithms and data structures used in our assembly program STROLL, which was used in the Brookhaven Borrelia project.
15833114
Exploring Gradient-Based Face Navigation Interfaces
We have created a gradient-based face navigation interface that allows users to explore a large face space based on an eigenface technique. This approach to synthesizing faces contrasts with more typical techniques for forming composite faces based on the blending of facial features. We compare three ways of moving through the face space, using two types of sliders and a face-wheel. These are adapted from typical color space interfaces since they are commonly used. However, eigenface dimensions do not have meaningful text labels, unlike primary colors, necessitating the use of faces themselves for the labels of the navigation axes. Results suggest that users can navigate with face-labelled axes. They find slider interfaces best suited to finding the neighborhood of a target face, but that the face-wheel is better for refinement once inside the neighborhood.
44631758
Agent-based forwarding strategies for reducing location management cost in mobile networks
A major issue with location management in mobile wireless networks is the high cost associated with location updates and searches. A search occurs when a caller needs to connect to a mobile user whose location is unknown to the caller and the network must locate the callee. An update occurs when a mobile user moves into a new registration area and the network is informed of the location change. We propose and analyze a class of new agent-based forwarding strategies with the objective to reduce the location management cost in mobile wireless networks. We develop analytical Markov models to compare the performance of the proposed strategies with existing location management schemes to demonstrate their feasibility and also to reveal conditions under which the proposed schemes are superior to existing ones.
2822926
Sorting with Fixed-length Reversals
Abstract A popular puzzle TOP-SPIN consists of a permutation of 20 numbered disks on an oval track, with a turnstile capable of reversing a string of 4 consecutive disks. The goal is to sort the disks into identity permutation using reversals. We consider the more general case of sorting n element permutations with a turnstile of size k. The problem of computing the reversal distances is of considerable importance in reconstructing the evolutionary history of the genome. The minimum reversal sequence sorting the one genome to another corresponds to the most likely evolutionary path between them. We give a complete solution for all n and k, of the number of equivalence classes of n-permutations under k-reversal, for both permutations and circular permutations. We also prove the upper and lower bounds on the reversal distances between two permutations.
34739655
On the Bisimulation Congruence in chi-Calculus
In this paper, we study weak bisimulation congruences for the χ-calculus, a symmetric variant of the π-calculus. We distinguish two styles of such bisimulation definitions, i.e. “open” and “closed” bisimulation, the difference between which lies in that in open style the equivalence is closed under context in every bisimulation step whereas in closed style the equivalence is closed under context only at the very beginning. As a result, we show that both in labelled and barbed congruence, the open and closed style definitions coincide. Thus all bisimulation congruences collapse into two equivalences, that is, the well-known open congruence and open barbed congruence, which are the same in the strong case, while in the weak case their difference can be reflected by one axiom. The results of this paper close some conjectures in the literatures and shed light on the algebraic theory of a large class of mobile process calculi.