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.
2500181
Video object segmentation and tracking using /spl psi/-learning classification
As a requisite of the emerging content-based multimedia technologies, video object (VO) extraction is of great importance. This paper presents a novel semiautomatic segmentation and tracking method for single VO extraction. Unlike traditional approaches, the proposed method formulates the separation of the VO from the background as a classification problem. Each frame is divided into small blocks of uniform size, which are called object blocks if the centering pixels belong to the object, or background blocks otherwise. After a manual segmentation of the first frame, the blocks of this frame are used as the training samples for the object-background classifier. A newly developed learning tool called /spl psi/-learning is employed to train the classifier which outperforms the conventional Support Vector Machines in linearly nonseparable cases. To deal with large and complex objects, a multilayer approach constructing a so-called hyperplane tree is proposed. Each node of the tree represents a hyperplane, responsible for classifying only a subset of the training samples. Multiple hyperplanes are thus needed to classify the entire set. Through the combination of the multilayer scheme and /spl psi/-learning, one can avoid the complexity of nonlinear mapping as well as achieve high classification accuracy. During the tracking phase, the pixel in the center of every block in a successive frame is classified by a sequence of hyperplanes from the root to a leaf node of the hyperplane tree, and the class of the block is identified accordingly. All the object blocks thus form the object of interest, whose boundary unfortunately is stair-like due to the block effect. In order to obtain the pixel-wise boundary in a cost efficient way, a pyramid boundary refining algorithm is designed, which iteratively selects a few informative pixels for class label checking, and reduces uncertainty about the actual boundary of the object. The proposed method has been applied on video sequences with various spatial and temporal characteristics, and experimental results demonstrate it to be effective, efficient, and robust.
16622032
AVP: A Highly Efficient Transport Protocol for Low Bit Rate Multimedia Communications
Utilization of Internet communications in distance learning, distributed simulation, and distributed work groups involves multimedia transmission of animation, voice and video clips. Highly compressed audio-video data protocols are required for efficient Internet multimedia communications. Addressing this requirement, a new transport protocol called Audio-Video Protocol (AVP) for highly efficient multimedia communications on the Internet is presented. While providing similar real-time delivery functions as Real-Time Transport Protocol (RTP) and Real-Time Control Protocol (RTCP), AVP adopts a novel audio-based synchronization scheme. This synchronization scheme has two advantages. One is the overhead reduction through eliminating the timestamp in each transmitted data packet. The other is the packet rate reduction by putting multiple audio frames or mixed audio-video frames in a single AVP packet. As a result, the end-to-end media unit delay is reduced while achieving implicit synchronization. Furthermore, AVP provides adaptive quality of service (QoS) by the prioritized packetization scheme. Simulation results are presented to verify the advantages of the AVP protocol.
8560106
Combined spatial and temporal domain wavelet shrinkage algorithm for video denoising
A combined spatial- and temporal-domain wavelet shrinkage algorithm for video denoising is presented in this paper. The spatial-domain denoising technique is a selective wavelet shrinkage method which uses a two-threshold criteria to exploit the geometry of the wavelet subbands of each video frame, and each frame of the image sequence is spatially denoised independently of one another. The temporal-domain denoising technique is a selective wavelet shrinkage method which estimates the level of noise corruption as well as the amount of motion in the image sequence. The amount of noise is estimated to determine how much filtering is needed in the temporal-domain, and the amount of motion is taken into consideration to determine the degree of similarity between consecutive frames. The similarity affects how much noise removal is possible using temporal-domain processing. Using motion and noise level estimates, a video denoising technique is established which is robust to various levels of noise corruption and various levels of motion.
646545
Designing and Evaluating an XPath Dialect for Linguistic Queries
Linguistic research and natural language processing employ large repositories of ordered trees. XML, a standard ordered tree model, and XPath, its associated language, are natural choices for linguistic data and queries. However, several important expressive features required for linguistic queries are missing or hard to express in XPath. In this paper, we motivate and illustrate these features with a variety of linguistic queries. Then we propose extensions to XPath to support linguistic queries, and design an efficient query engine based on a novel labeling scheme. Experiments demonstrate that our language is not only sufficiently expressive for linguistic trees but also efficient for practical usage.
13563503
A testbed for quantitative assessment of intrusion detection systems using fuzzy logic
The current intrusion detection system (IDS) technology is a major investment for a firm and its evaluation is desired prior to a commitment. A testbed compares different IDSs on a common platform. A major challenge in evaluating IDSs stems from the fact that they are generally tested in specific environments. A real-world environment could be different from the environment designed for a testbed. The results obtained, from such testbeds, may not be accurate and reliable. Hence, a quantitative and metrics based evaluation of IDSs is desired. We propose testbed for evaluating intrusion detection systems (TIDeS), that allows a user to select the best IDS for a specific customized environment. A quantitative analysis is provided by TIDeS, using fuzzy logic, under varying network loads. We also propose robust metrics to evaluate an IDS. We follow up with recommendations, based on our experience, on the general practices in the field of IDSs.
6113265
Immunizing Public Key Cryptosystems Against Chosen Ciphertext Attacks
Three methods for strengthening public key cryptosystems in such a way that they become secure against adaptively chosen ciphertext attacks are presented. In an adaptively chosen ciphertext attack, an attacker can query the deciphering algorithm with any ciphertext except for the exact object ciphertext to be cryptanalyzed. The first strengthening method is based on the use of one-way hash functions, the second on the use of universal hash functions, and the third on the use of digital signature schemes. Each method is illustrated by an example of a public key cryptosystem based on the intractability of computing discrete logarithms in finite fields. Security of the three example cryptosystems is formally proved. Two other issues, namely, applications of the methods to public key cryptosystems based on other intractable problems and enhancement of information authentication capability to the cryptosystems, are also discussed. >
1719358
A BPSK demodulator circuit using an anti-parallel synchronization loop
A novel anti-parallel loop carrier synchronization method for BPSK demodulation is proposed and demonstrated. The method contains an anti-parallel dual loop, which locks the carrier by its upper loop and lower loop alternately, according to the data bits contained in the received BPSK signal. Simulation and experimental results are shown along with BER performance.
154656
Relationships between Bent Functions and Complementary Plateaued Functions
We introduce the concept of complementary plateaued functions and examine relationships between these newly defined functions and bent functions. Results obtained in this paper contribute to the further understanding of profound secrets of bent functions. Cryptographic applications of these results are demonstrated by constructing highly nonlinear correlation immune functions that possess no non-zero linear structures.