Fast similarity search on video signatures
Video signatures are compact representations of video sequences designed for efficient similarity measurement. In this paper, we propose a feature extraction technique to support fast similarity search on large databases of video signatures. Our proposed technique transforms the high dimensional video signatures into low dimensional vectors where similarity search can be efficiently performed. We exploit both the upper and lower bounds of the triangle inequalities in approximating the high-dimensional metric, and combine this approximation with the classical PCA to achieve the target dimension. Experimental results on a large set of Web video sequences show that our technique outperforms fastmap, Haar wavelet, PCA, and triangle-inequality pruning.

title: Fast similarity search and clustering of video sequences on the world-wide-web
abstract: We define similar video content as video sequences with almost identical content but possibly compressed at different qualities, reformatted to different sizes and frame-rates, undergone minor editing in either spatial or temporal domain, or summarized into keyframe sequences. Building a search engine to identify such similar content in the World-Wide Web requires: 1) robust video similarity measurements; 2) fast similarity search techniques on large databases; and 3) intuitive organization of search results. In a previous paper, we proposed a randomized technique called the video signature (ViSig) method for video similarity measurement. In this paper, we focus on the remaining two issues by proposing a feature extraction scheme for fast similarity search, and a clustering algorithm for identification of similar clusters. Similar to many other content-based methods, the ViSig method uses high-dimensional feature vectors to represent video. To warrant a fast response time for similarity searches on high dimensional vectors, we propose a novel nonlinear feature extraction scheme on arbitrary metric spaces that combines the triangle inequality with the classical Principal Component Analysis (PCA). We show experimentally that the proposed technique outperforms PCA, Fastmap, Triangle-Inequality Pruning, and Haar wavelet on signature data. To further improve retrieval performance, and provide better organization of similarity search results, we introduce a new graph-theoretical clustering algorithm on large databases of signatures. This algorithm treats all signatures as an abstract threshold graph, where the distance threshold is determined based on local data statistics. Similar clusters are then identified as highly connected regions in the graph. By measuring the retrieval performance against a ground-truth set, we show that our proposed algorithm outperforms simple thresholding, single-link and complete-link hierarchical clustering techniques.

title: The chaos router chip: design and implementation of an adaptive router

title: Efficient video similarity measurement and search
abstract: We consider the use of meta-data and/or video-domain methods to detect similar videos on the Web. Meta-data is extracted from the textual and hyperlink information associated with each video clip. In the video domain, we apply an efficient similarity detection algorithm called video signature. The idea is to form a signature for each clip by selecting a small number of its frames that are most similar to a set of random seed images. We then apply a statistical pruning algorithm to allow fast detection on very large databases. Using a small ground-truth set, we achieve 90% recall and 95% precision using only 8% of the total number of operations required without pruning. For a database of around 46,000 video clips crawled from the Web, the video signature technique significantly outperforms meta-data in precision and recall. We show that even better performance can be achieved by combining them together. Based on our measurements, each video clip in our database has, on average, 1.53 similar copies.

title: A model-based authorware for the construction of distributed multimedia systems
abstract: Distributed multimedia systems typically involve a sophisticated user interaction. Further, objects are allocated on physically distributed computing systems, and multimedia data must be transferred across heterogeneous networks in a timely manner. These systems often have complex requirements on a user interaction, quality of service and temporal order among media streams. The design and implementation of these requirements are inherently complex and present an extraordinary design and programming challenge. Generally, these complex requirements cannot be adequately captured using a single model or a design notation. The challenge amounts to (i) identification of multiple, often orthogonal models, each capturing a specific aspect of the requirements, and (ii) provision of an authorware that supports the composition of these models. In this paper, we propose to capture the multimedia requirements in three different models: configuration, user control and presentation, and demonstrate how the composition of these models can be supported by an authorware using the Java and CORBA technologies. The concepts are illustrated using a real-life example based on a virtual city tour application that features distributed controls, collaborative work and multimedia presentations. Various distributed multimedia applications like video phone, video conferencing and distributed presentation have been successfully constructed using the proposed multiple models and authorware. The results are encouraging and the approach can shorten the development of multimedia applications considerably.

title: An efficient message authentication scheme for link state routing
abstract: We study methods for reducing the cost of secure link state routing. In secure link state routing, routers may need to verify the authenticity of many routing updates, and some routers such as border routers may need to sign many routing updates. Previous work such as public-key based schemes are very expensive computationally or have certain limitations. This paper presents an efficient solution, based on a detection-diagnosis-recovery approach, for the link state routing update authentication problem. Our scheme is scalable to handle large networks, applicable to routing protocols that use multiple-valued cost metrics, and applicable even, when link states change frequently.

title: Rights protection for digital contents redistribution over the Internet
abstract: Although the customer-to-customer (C2C) business model has been around for years, second-hand markets of digital contents over the Internet are still unpopular. A key factor to the success of second-hand markets lies in the support of rights management of digital contents redistribution over the Internet. Although various watermarking protocols have been proposed to achieve digital rights protection over the Internet, they do not generally provide protection over a second-hand market. We propose a buyer-reseller watermarking protocol that protects the interests of buyers, resellers and the original sellers. The protocol is adapted from a previous work proposed by Memon and Wong (2001), which defends the interests of buyers against sellers' unethical distribution of watermarked contents. Our protocol makes use of watermark certificates to distribute the information of buyers' identities. An implementation outline of the proposed protocol is given.

title: Dependable Intrusion Tolerance: technology demo
abstract: The Dependable Intrusion Tolerance (DIT) architecture is a flexible, adaptive, and intrusion-tolerant server design. We briefly discuss its prototype implementation and validation, and demonstrate how it resists sample attacks.

title: Routing with Locality on Meshes with Buses
abstract: Routing with locality is studied for meshes with buses. In this problem, packets' distances are bounded by a value,d, which is less than the diameter of the network. This problem arises naturally when specific known algorithms are implemented on meshes. Solving this problem in ordinary meshes requires at least a routing time ofdsteps. To do better than this, we propose adding a kind of short bus to ordinary meshes. By using a technique which we call iterative walk-and-ride, we show how the routing time can be reduced by approximately one-third for solving the problem (including the multipacket version) on one- and two-dimensional short-bus meshes. The bounds we develop are tight.