7386649
Genetic Representations for Evolutionary Minimization of Network Coding Resources
We demonstrate how a genetic algorithm solves the problem of minimizing the resources used for network coding, subject to a throughput constraint, in a multicast scenario. A genetic algorithm avoids the computational complexity that makes the problem NP-hard and, for our experiments, greatly improves on sub-optimal solutions of established methods. We compare two different genotype encodings, which tradeoff search space size with fitness landscape, as well as the associated genetic operators. Our finding favors a smaller encoding despite its fewer intermediate solutions and demonstrates the impact of the modularity enforced by genetic operators on the performance of the algorithm.
63258
A doubly distributed genetic algorithm for network coding
We present a genetic algorithm which is distributed in two novel ways: along genotype and temporal axes. Our algorithm first distributes, for every member of the population, a subset of the genotype to each network node, rather thana subset of the population to each. This genotype distribution is shown to offer a significant gain in running time. Then, for efficient use of the computational resources in the network, our algorithm divides the candidate solutions intopipelined sets and thus the distribution is in the temporal domain, rather that in the spatial domain. This temporal distribution may lead to temporal inconsistency in selection and replacement, however our experiments yield better efficiency in terms of the time to convergence without incurring significant penalties.
18865506
Watermarking of 3D Irregular Meshes Based on Wavelet Multiresolution Analysis
In this paper, we propose a robust watermarking method for 3-D triangle surface meshes. Most previous methods based on the wavelet analysis can process only semi-regular meshes. Our proposal can be applied to irregular as well as regular meshes by using recently introduced irregular wavelet analysis scheme. L2-Norm of the wavelet coefficients is modified in various multi-resolution levels to embed the watermark. We also introduced a vertex and face re-ordering process as pre-processing in both watermark embedding and extraction for the robustness against connectivity reordering attacks. In addition, our proposal employs blind watermark detection scheme, which can extract the watermark without reference of cover mesh model. Through the simulations, we prove that our approach is robust against connectivity reordering as well as various kinds of geometrical attacks such as lossy compression and affine transform.
6041360
Modeling timed user-interactions in multimedia documents
Interactive multimedia documents (or systems) can be characterized by active user participation and the diversity of multimedia information accessed at various levels of granularity. They need to support extensive user participation in selecting and tailoring the information and its presentation. Multimedia information fragments may vary from portions of video, pieces of audio, newspaper quotations or chapters of a book. Effectively managing the creation, evolution and complexity of multimedia documents formed by combining media fragments is an essential capability. We consider the hyperstory model of a multimedia document, where a document is structured hierarchically in three dimensions: time, space and asynchrony. The model provides a layered approach in structuring multimedia documents, thus reducing the complexities of large systems. The hyperstory model supports user interactions that are timed, and also supports preemptive resuming. Timed user interactions with the document are modeled with a newly introduced timed Petri-net (TPN*). TPN* is used to infer the behavior of the system. This paper describes TPN*'s modeling and analysis and its application to the hyperstory model.
10669533
Optimal distribution tree for Internet streaming media
Internet radio and television stations require significant bandwidth to support delivery of high quality audio and video streams to a large number of receivers. IP multicast is an appropriate delivery model for these applications. However, widespread deployment of IP multicast on the Internet is unlikely in the near future. An alternative is to build a multicast tree in the application layer Previous studies have addressed tree construction in the application layer However most of them focus on reducing delay. Few systems have been designed to achieve a high throughput for bandwidth-intensive applications. In this paper we present a distributed algorithm to build an application-layer tree. We prove that our algorithm finds a tree such that the average incoming rate of receivers in the tree is maximized (under certain network model assumptions). We also describe protocols that implement the algorithm. For implementation on the Internet, there is a tradeoff between the overhead of available bandwidth measurements and fast convergence to the optimal tree. This tradeoff can be controlled by tuning some parameters in our protocols. Our protocols are also designed to maintain a small number, O(log n), of soft states per node to adapt to network changes and node failures.
26955217
On Temporal Aggregate Processing Based on Time Points
Temporal aggregation is an extension of conventional aggregate on the domain and range of aggregates to include the time concept. In this paper, we propose a new tree-based temporal aggregation processing method. The time complexity of the proposed method is better than those of the existing methods. The experimental results indicate that our proposed method ourperforms the existing methods.
1461453
Optimal partitioning of multicast receivers
Multicast sessions may have a large number of receivers with heterogeneous reception capacities. To accommodate this heterogeneity various multi-rate schemes, based upon the use of layering or replication, have been proposed. We consider the optimal partitioning of receivers into groups for multi-rate schemes. For a general class of utility functions, we formulate the partitioning problem as an optimization problem to maximize the sum of receiver utilities. We present an efficient dynamic programming algorithm to solve the partitioning problem, and prove that the solution it finds is optimal. We also show that the majority of the benefit of a multi-rate scheme can be gained by using a small number of groups (or layers), say 4 to 5. To illustrate our solution approach, we apply it to the case where receiver capacities are determined by multi-rate max-min fair rates. A complete protocol for receiver rates computation, rates collection, optimal receiver partitioning, and receiver adaptation is presented. We then compare our approach with other multi-rate approaches as well as a single-rate approach. Experimental results show that our approach provides substantial performance improvements.