7408654
Security evaluation for communication-friendly encryption of multimedia
This paper addresses the access control issues unique to multimedia, by using a joint signal processing and cryptographic approach to multimedia encryption. Based on three atomic encryption primitives, we present a systematic study on how to strategically integrate different atomic operations to build a video encryption system. We also propose a set of multimedia-specific security metrics to quantify the security against approximation attacks and to complement the existing notion of generic data security. The resulting system can provide superior performance to both generic encryption and its simple adaptation to video in terms of a joint consideration of security, bitrate overhead, and communication friendliness.
18637696
Forensic analysis of nonlinear collusion attacks for multimedia fingerprinting
Digital fingerprinting is a technology for tracing the distribution of multimedia content and protecting them from unauthorized redistribution. Unique identification information is embedded into each distributed copy of multimedia signal and serves as a digital fingerprint. Collusion attack is a cost-effective attack against digital fingerprinting, where colluders combine several copies with the same content but different fingerprints to remove or attenuate the original fingerprints. In this paper, we investigate the average collusion attack and several basic nonlinear collusions on independent Gaussian fingerprints, and study their effectiveness and the impact on the perceptual quality. With unbounded Gaussian fingerprints, perceivable distortion may exist in the fingerprinted copies as well as the copies after the collusion attacks. In order to remove this perceptual distortion, we introduce bounded Gaussian-like fingerprints and study their performance under collusion attacks. We also study several commonly used detection statistics and analyze their performance under collusion attacks. We further propose a preprocessing technique of the extracted fingerprints specifically for collusion scenarios to improve the detection performance.
10044678
Anti-collusion codes: multi-user and multimedia perspectives
Digital fingerprinting is an effective method to identify users who might try to redistribute multimedia content, such as images and video. These fingerprints are typically embedded into the content using watermarking techniques that are designed to be robust to a variety of attacks. A cheap and effective attack against such digital fingerprints is collusion, where several differently marked copies of the same content are averaged or combined to disrupt the underlying fingerprint. We present a construction of collusion-resistant fingerprints based upon anti-collusion codes (ACC) and binary code modulation. ACC have the property that the composition of any subset of K or fewer codevectors is unique. Using this property, we build fingerprints that allow for the identification of groups of K or less colluders. We present a construction of binary-valued ACC under the logical AND operation using the theory of combinatorial designs. Our code construction requires only /spl Oscr/(/spl radic/n) orthogonal signals to accommodate n users. We demonstrate the performance of our ACC for fingerprinting multimedia by identifying colluders through experiments using real images.
6845274
Fingerprinting Curves
This paper presents a new method for robust data hiding in curves and highlights potential applications including digital fingerprinting of map document for trace and track purposes. We parameterize a curve using the B-spline model and add a spread spectrum sequence to the coordinates of the B-spline control points. In order to achieve robust fingerprint detection, we propose an iterative alignment-minimization algorithm to perform curve registration and deal with the non-uniqueness of B-spline control points. We show through experiments the robustness of our method against various attacks such as collusion, geometric transformations and perturbation, printing-and-scanning, and some of their combinations. We demonstrate the feasibility of our method for fingerprinting topographic maps as well as writings and drawings. The extension from hiding data in 2D topographic maps to 3D elevation data sets is also discussed.
1384427
Classification-based spatial error concealment for images
This paper presents a new, classification-based spatial error concealment algorithm for images. The proposed scheme takes advantage of two state-of-the-art concealment schemes and adaptively selects a better suitable concealment scheme for each corrupted block. Using a support vector machine (SVM) classifier, our proposed approach outperforms the prior art in terms of the concealment quality and has moderate computational complexity.
12822689
Data hiding in curves for collusion-resistant digital fingerprinting
This paper presents a new data hiding method for curves. The proposed algorithm parameterizes a curve using the B-spline model and adds a spread spectrum sequence in the coordinates of the B-spline control points. We demonstrate through experiments the robustness of the proposed data hiding algorithm against printing-and-scanning and collusions, and show its feasibility for collusion-resistant fingerprinting of topographic maps as well as writings/drawings from pen-based input devices.
17440253
Question-driven classification of retrieved documents
Many existing information access systems deliver ranked lists of documents in response to users' queries. Some systems also endeavour to represent some of the various types of relationships that can exist between documents. However, few systems provide effective mechanisms to help users discover useful information within the set of retrieved documents. In this paper, we present a question-driven approach to delivering retrieved documents in an attempt to organize them in a way that is closer to the user's mental representation of the expected answer. In our proposed approach, retrieved documents are dynamically classified into categories; an appropriate classification scheme is selected by a user on the basis of his own understanding of the information need. Experimental results show that users are more satisfied with such a directed categorization than with a list of retrieved documents.
9371851
Under My Finger: Human Factors in Pushing and Rotating Documents Across the Table
When passing a document to someone across a table, the person passing the document often rotates it to face the receiver. In this paper, we present the results of a user evaluation of three Push-and-Rotate schemes that offer different underlying control semantics for how an electronic document can automatically rotate as it is pushed across an interactive tabletop surface. The effects of document size are also discussed.
1121557
Query optimization for selections using bitmaps
Bitmaps are popular indexes for data warehouse (DW) applications and most database management systems offer them today. This paper proposes query optimization strategies for selections using bitmaps. Both continuous and discrete selection criteria are considered. Query optimization strategies are categorized into static and dynamic. Static optimization strategies discussed are the optimal design of bitmaps, and algorithms based on tree and logical reduction. The dynamic optimization discussed is the approach of inclusion and exclusion for both bit-sliced indexes and encoded bitmap indexes.
31560341
The role of a judge in a user based retrieval experiment (poster session)
A tuning device for tympani that displays the pitch of each instrument's tympanum. The pitch is determined by measuring the strain in an adjustable tensioning mechanism employed in all tympani to keep proper tension on the tympanum. The pitch or tone of the tympani is determined by the vibration frequency of the tympanum when the tympani is played and the frequency is determined by the tension in the tympanum. A transducer measures the strain in the tensioning mechanism to give an accurate indication of what the tympanum tension, and therefore the pitch, of the tympani would be when played. The transducer includes a resistance-type strain gage mounted on the tympanum tensioning mechanism. The length of the conductor in the strain gage and therefore its resistance, changes with stress changes in the tensioning mechanism used to tune the tympani. A switch means selects a desired one of the strain gages mounted on each of the one or more tympani for inclusion as one section of a four-section resistance bridge circuit configuration. A signal conditioning module provides excitation to the bridge circuit and also conditions the output of the bridge circuit. The output of the bridge circuit varies as the resistance of the strain gage varies. The conditioned output of the bridge circuit is displayed on a voltmeter whose scale has been calibrated to indicate the pitch of the tympani being monitored.
13570236
Research Issues in Data Warehousing
Data warehousing is a booming industry with many interesting research problems. The database research community has concentrated on only a few aspects. In this paper, We summarize the state of the art, suggest architectural extensions and identify research problems in the areas of warehouse modeling and design, data cleansing and loading, data refreshing and purging, metadata management, extensions to relational operators, alternative implementations of traditional relational operators, special index structures and query optimization with aggregates.