33641222
Object tracking using the Gabor wavelet transform and the golden section algorithm
The paper presents an object tracking method for object-based video processing which uses a two-dimensional (2D) Gabor wavelet transform (GWT) and a 2D golden section algorithm. An object in the current frame is modeled by local features from a number of the selected feature points, and the global placement of these feature points. The feature points are stochastically selected based on the energy of their GWT coefficients. Points with higher energy have a higher probability of being selected since they are visually more important. The amplitudes of the GWT coefficients of a feature point are then used as the local feature. The global placement of the feature points is determined by a 2D mesh whose feature is the area of the triangles formed by the feature points. In this way, a local feature is represented by a GWT coefficient amplitude vector, and a global feature is represented by a triangle area vector. One advantage of the 2D mesh is that the direction of its triangle area vector is invariant to affine transform. Consequently, the similarity between two local features or two global features can be defined as a function of the angle and the length ratio between two vectors, and the overall similarity between two objects is a weighted sum of the local and global similarities. In order to find the corresponding object in the next frame, the 2D golden section algorithm is employed. Our results show that the method is robust to object deformation and supports object tracking in noisy video sequences.
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.
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.
2310959
XKvalidator: a constraint validator for XML
The role of XML in data exchange is evolving from one of merely conveying the structure of data to one that also conveys its semantics. In particular, several proposals for key and foreign key constraints have recently appeared, and aspects of these proposals have been adopted within XMLSchema.In this paper, we examine the problem of checking keys and foreign keys in XML documents using a validator based on SAX. The algorithm relies on an indexing technique based on the paths found in key definitions, and can be used for checking the correctness of an entire document (bulk checking) as well as for checking updates as they are made to the document (incremental checking). The asymptotic performance of the algorithm is linear in the size of the document or update. Furthermore, experimental results demonstrate reasonable performance.
790881
Compact and unforgeable key establishment over an ATM network
Authenticated session key establishment is a central issue in network security. This paper addresses the question of whether we can design a compact, efficient and authenticated key establishment protocol that has the following two properties: (1) each message exchanged between two participants can be transferred in a short packet such as an ATM cell whose payload has only 384 bits, and (2) messages that carry key materials are unforgeable and nonrepudiatable without the involvement of a trusted key distribution center. We discuss why the answer to this question is negative if one follows the currently standard approach to key establishment, namely employing secret/public key encryption and, possibly, digital signature. We then present a number of protocols that represent a positive answer to the question. Our protocols are all based on a cryptographic primitive called "signcryption" that fulfils both the functions of digital signature and public key encryption with a cost far smaller than that required by "digital signature followed by encryption".
16731284
Efficient Unconditionally Secure Digital Signatures
SUMMARY Digital signatures whose security does not rely on any unproven computational assumption have recently received considerable attention. While these unconditionally secure digital signatures provide a foundation for long term integrity and non-repudiation of data, currently known schemes generally require a far greater amount of memory space for the storage of secret and public keys than a traditional digital signature. The focus of this paper is on methods for reducing memory requirements of unconditionally secure digital signatures. A major contribution of this paper is to propose two novel unconditionally secure digital signature schemes, one called a symmetric construction and other an asymmetric construction, which require a significantly smaller amount of memory. As a specific example, with a typical parameter setting the required memory size for a user is reduced to be approximately 1 10 of that in a previously known scheme. Another contribution of the paper is to show an attack on a multireceiver authentication code which was proposed by Safavi-Naini and Wang. A simple method to fix the problem of the multireceiver authentication code is also proposed.
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.
15341893
The SPEED Cipher
SPEED is a private key block cipher. It supports three variable parameters: (1) data length — the length of a plaintext/ciphertext of SPEED can be 64, 128 or 256 bits. (2) key length — the length of an encryption/decryption key of SPEED can be any integer between 48 and 256 (inclusive) and divisible by 16. (3) rounds — the number of rounds involved in encryption/decryption can be any integer divisible by 4 but not smaller than 32.