10569326
Intelligent compliant motion control
The role of a compliant motion scheme is to control a robot manipulator in contact with its environment. By accommodating with the interaction force, the manipulator can be used to accomplish tasks that involve constrained motions. This paper presents a new work on the compliant motion control for position-controlled manipulator. A new method for achieving efficient interaction between the manipulator and its environment is developed. The interaction force is reduced using a quadratic cost function. In this method, the compliance is formulated as function of the interaction force. An adaptive element is used to update the compliance. The stability of the system is investigated using the Lyapunov approach. Experiments are conducted in our laboratory to demonstrate the use of such scheme.
15990035
Content-based retransmission for 3-D wavelet video streaming on the Internet
Improving the QoS of video streaming with packet loss is a challenging topic of research. In this paper, we propose a novel content-based retransmission scheme to address this issue. The basic idea is to jointly consider the packets' contents and the channel conditions to optimize QoS. The goal is to deliver the best quality of video possible under the same channel condition. Using the proposed retransmission scheme, we have designed a 3D wavelet video streaming system. Simulation results show that the content-based retransmission can improve the video quality by more than 2 dB compared with the existing non-content-based delay-constrained retransmission when the channel loss rate is high.
46651638
Packed integer wavelet transform constructed by lifting scheme
A new method for speeding up the integer wavelet transforms constructed by the lifting scheme is proposed. The proposed method packs multiple pixels (wavelet coefficients) in a single word; therefore, it can make use of the 32-bit or 64-bit computational capability of modern computers to accomplish multiple addition/subtraction operations in one instruction cycle. As a result, our method can save the decomposition/reconstruction time by up to 37% on 32-bit machines and require much less working memory in comparison with the original wavelet transform algorithms.
29740611
Restriction, Terms and Nonlinearity of Boolean Functions
Nonlinear characteristics of (Boolean) functions is one of the important issues both in the design and cryptanalysis of (private key) ciphers or encryption algorithms. This paper studies nonlinear properties of functions from three different but closely related perspectives: maximal odd weighting subspaces, restrictions to cosets, and hypergraphs, all associated with a function. Main contributions of this work include (1) by using a duality property of a function, we have obtained several results that are related to lower bounds on nonlinearity as well as on the number of terms, of the function, (2) we show that the restriction of a function on a coset has a significant impact on cryptographic properties of the function, (3) we identify relationships between the nonlinearity of a function and the distribution of terms in the algebraic normal form of the function, (4) we prove that cycles of odd length in the terms, as well as quadratic terms, in the algebraic normal form of a function play an important role in determining the nonlinearity of the function. We hope that these results contribute to the study of new cryptanalytic attacks on ciphers, and more importantly, of counter-measures against such attacks.
3127804
On plateaued functions
The focus of this article is on nonlinear characteristics of cryptographic Boolean functions. First, we introduce the notion of plateaued functions that have many cryptographically desirable properties. Second, we establish a sequence of strengthened inequalities on some of the most important nonlinearity criteria, including nonlinearity, avalanche, and correlation immunity, and prove that critical cases of the inequalities coincide with characterizations of plateaued functions. We then proceed to prove that plateaued functions include as a proper subset all partially bent functions that were introduced earlier by Claude Carlet (1993). This solves an interesting problem that arises naturally from previously known results on partially bent functions. In addition, we construct plateaued, but not partially bent, functions that have many properties useful in cryptography.
5135938
Privacy preserving database application testing
Traditionally, application software developers carry out their tests on their own local development databases. However, such local databases usually have only a small number of sample data and hence cannot simulate satisfactorily a live environment, especially in terms of performance and scalability testing. On the other hand, the idea of testing applications over live production databases is increasingly problematic in most situations primarily due to the fact that such use of live production databases has the potential to expose sensitive data to an unauthorized tester and to incorrectly update information in the underlying database. In this paper, we investigate techniques to generate mock databases for application software testing without revealing any confidential information from the live production databases. Specifically, we will design mechanisms to create the deterministic rule set R, non-deterministic rule set N R, and statistic data set S for a live production database. We will then build a security Analyzer which will process the triplet <R',N R',S'> together with security requirements (security policy) and output a new triplet <R',N R',S'> The security Analyzer will guarantee that no confidential information could be inferred from the new triplet <R',N R',S'> The mock database generated from this new triplet can simulate the live environment for testing purpose, while maintaining the privacy of data in the original database.
10928867
Nonlinearity and Propagation Characteristics of Balanced Boolean Functions
Abstract Three important criteria for cryptographically strong Boolean functions are balance, nonlinearity, and the propagation criterion. The main contributions of this paper are to reveal a number of interesting properties of balance and nonlinearity, and to study systematic methods for constructing Boolean functions that satisfy some or all of the three criteria. We show that concatenating, splitting, modifying, and multiplying (in the sense of Kronecker) sequences can yield balanced Boolean functions with a very high nonlinearity. In particular, we show that balanced Boolean functions obtained by modifying and multiplying sequences achieve a nonlinearity higher than that attainable by any previously known construction method. We also present methods for constructing balanced Boolean functions that are highly nonlinear and satisfy the strict avalanche criterion (SAC). Furthermore we present methods for constructing highly nonlinear balanced Boolean functions satisfying the propagation criterion with respect to all but one or three vectors. A technique is developed to transform the vectors where the propagation criterion is not satisfied in such a way that the functions constructed satisfy the propagation criterion of high degree while preserving the balance and nonlinearity of the functions. The algebraic degrees of functions constructed are also discussed.
14223982
Statistical Database Modeling for Privacy Preserving Database Generation
Testing of database applications is of great importance. Although various studies have been conducted to investigate testing techniques for database design, relatively few efforts have been made to explicitly address the testing of database applications which requires a large amount of representative data available. As testing over live production databases is often infeasible in many situations due to the high risks of disclosure of confidential information or incorrect updating of real data, in this paper we investigate the problem of generating synthetic database based on a-priori knowledge about production database. Our approach is to fit general location model using various characteristics (e.g., constraints, statistics, rules) extracted from production database and then generate synthetic data using model learnt. As characteristics extracted may contain information which may be used by attacker to derive some confidential information, we present a disclosure analysis method which is based on cell suppression technique. Our method is effective and efficient to remove aggregate private information during data generation.