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2007
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| |  | Lian, S. | Commutative Encryption and Watermarking in Video Compression read moreAbstract: A scheme is proposed to implement commutative video encryption and watermarking during advanced video coding process. In H.264/AVC compression, the intra-prediction mode, motion vector difference and discrete cosine transform (DCT) coefficients' signs are encrypted, while DCT coefficients' amplitudes are watermarked adaptively. To avoid that the watermarking operation affects the decryption operation, a traditional watermarking algorithm is modified. The encryption and watermarking operations are commutative. Thus, the watermark can be extracted from the encrypted videos, and the encrypted videos can be re-watermarked. This scheme embeds the watermark without exposing video content's confidentiality, and provides a solution for signal processing in encrypted domain. Additionally, it increases the operation efficiency, since the encrypted video can be watermarked without decryption. These properties make the scheme a good choice for secure media transmission or distribution.  This article is not yet tagged | 2007 |
| | | Wang, H. | Vector Gaussian Multiple Description With Individual and Central Receivers read moreAbstract: $L$ multiple descriptions of a vector Gaussian source for individual and central receivers are investigated. The sum rate of the descriptions with covariance distortion measure constraints, in a positive semidefinite ordering, is exactly characterized. For two descriptions, the entire rate region is characterized. The key component of the solution is a novel information-theoretic inequality that is used to lower-bound the achievable multiple description rates. Jointly Gaussian descriptions are optimal in achieving the limiting rates. We also show the robustness of this description scheme: the distortions achieved are no larger when used to describe any non-Gaussian source with the same covariance matrix. This article is not yet tagged | 2007 |
| | | Wang, H. | An Efficient Mode Decision Algorithm for H.264/AVC Encoding Optimization read moreAbstract: The H.264 video coding standard significantly outperforms previous standards in terms of coding efficiency. However, this comes as a cost of extremely high computational complexity due to mode decision where variable block size Motion Estimation (ME) is employed. In this paper, we propose an efficient algorithm to jointly optimize mode decision and ME. A theoretical analysis is performed to study the sufficient condition to detect all-zero blocks in H.264, and thus adaptive thresholds are derived to early terminate mode decision and ME. Besides the aforementioned early termination technique, the proposed algorithm also introduces temporal-spatial checking, thresholds based prediction and monotonic error surface based prediction methods to skip checking unnecessary modes. Experimental results demonstrate that the proposed algorithm can significantly reduce the computational complexity of H.264 encoding while maintaining almost the same Rate Distortion (RD) performance as the original encoder. This article is not yet tagged | 2007 |
| | | Wang, H. | Hybrid Model to Detect Zero Quantized DCT Coefficients in H.264 read moreAbstract: In H.264 coding, there are a large number of discrete cosine transform (DCT) coefficients of the prediction residue which are quantized to zeros. Therefore, it is desired to design a method which can early detect zero quantized DCT coefficients (ZQDCT) before implementing DCT and quantization (Q) and thus reduce redundant computations for H.264 coding. To achieve this, a hybrid model is proposed in this paper in order to predict ZQDCT coefficients. First, the Gaussian distribution is applied to study the integer DCT coefficients in H.264 and hence an adaptive scheme with multiple thresholds is derived to realize different types of DCT and Q implementations. Then the adaptive scheme is further optimized by considering a more efficient condition to sufficiently detect all-zero DCT blocks. As a result, a hybrid model is developed. Compared with other methods in the literature, the proposed hybrid model is able to detect more ZQDCT coefficients and hence reduce more computations for H.264 encoding. It is shown by experimental results that the proposed hybrid model can achieve the best performance in reducing computations and obtain almost the same rate-distortion (R-D) performance as the original encoder in the H.264 reference software JM9.5. This article is not yet tagged | 2007 |
| | | Zheng, H. | Cyclic System Reconfiguration and Time-Split Signal Separation With Applications to Lung Sound Pattern Analysis read moreAbstract: This paper presents a new technique for noise cancellation and signal separation, which is capable of identifying channel dynamics in real time, removing noise effectively, and separating source signals by reconfiguring signal transmission channels during different phases of source signals. This method is motivated by extracting authentic heart and lung sounds for anesthesia diagnosis when auscultated sounds contain interference and noise corruption, but has broader applications as long as the source signals nonsynchronously go through existence and almost nonexistence stages cyclicly. This article is not yet tagged | 2007 |
| | | Huang, P. -. | A Low-Power 114-GHz Push–Push CMOS VCO Using <emphasis emphasistype="italic">LC</emphasis> Source Degeneration read moreAbstract: An LC source-degeneration negative-resistance cell of an LC VCO is investigated, which is capable of operating at millimeter-wave (MMW) range with low dc power consumption. Several negative-resistance cells in LC oscillators are also compared. The LC source-degenerated topology is demonstrated through a 114-GHz push-push fully integrated LC VCO implemented in TSMC 0.13-$mu$m CMOS process. With core power consumption of 8.4 mW, the tuning range at the fundamental port is 56.4–57.6 GHz and at the push-push port is 112.8–115.2 GHz. The measured phase noise at the fundamental port is ${-}$113.6 dBc/Hz at 10-MHz offset. This VCO is believed to have the best figure of merit among MMW VCOs using bulk CMOS processes. This article is not yet tagged | 2007 |
| | | Yang, J. -. | Optimization Models for Training Belief-Rule-Based Systems read moreAbstract: A belief Rule-base Inference Methodology using the Evidential Reasoning approach (RIMER) has been developed recently, where a new belief rule representation scheme is proposed to extend traditional IF–THEN rules. The belief rule expression matrix in RIMER provides a compact framework for representing expert knowledge. However, it is difficult to accurately determine the parameters of a belief rule base (BRB) entirely subjectively, particularly, for a large-scale BRB with hundreds or even thousands of rules. In addition, a change in rule weight or attribute weight may lead to changes in the performance of a BRB. As such, there is a need to develop a supporting mechanism that can be used to train, in a locally optimal way, a BRB that is initially built using expert knowledge. In this paper, several new optimization models for locally training a BRB are developed. The new models are either single- or multiple-objective nonlinear optimization problems. The main feature of these new models is that only partial input and output information is required, which can be either incomplete or vague, either numerical or judgmental, or mixed. The models can be used to fine tune a BRB whose internal structure is initially decided by experts' domain-specific knowledge or common sense judgments. As such, a wide range of knowledge representation schemes can be handled, thereby facilitating the construction of various types of BRB systems. Conclusions drawn from such a trained BRB with partially built-in expert knowledge can simulate real situations in a meaningful, consistent, and locally optimal way. A numerical study for a hierarchical rule base is examined to demonstrate how the new models can be implemented as well as their potential applications. This article is not yet tagged | 2007 |
| | | Wang, H. | Random Unitary Beamforming With Partial Feedback for MISO Downlink Transmission Using Multiuser Diversity read moreAbstract: In this paper, we study the problem of downlink transmission in multiple-input-single-output (MISO) wireless communication systems using multiuser diversity. There are $M$ antennas at the base station (BS) and $K$ single-antenna receivers. The performance of multiuser diversity depends on the number of users that have independent channel realizations. It is well known that increasing the number of users improves the performance at the expense of increasing feedback that is proportional to the number of users. For sufficiently large $K$, the capacity scales like $Mlog log K$. When $K$ is large, increasing feedback limits practical applications of the multiuser diversity. Our approach is to reduce the feedback by selecting a threshold for the $ell _{infty}$ -norm of the normalized cross-correlation $(Vert {bf z}_{k}Vert _{infty })$ between the users' channel and the beamforming matrix based on the random unitary beamforming. The average amount of feedback per time slot is $d$ real numbers and $d$ integers which does not change with $K$. To improve fairness, an equal ratio scheduling algorithm which could serve the users with different rate requirements is developed. Monte Carlo simulation results is provided to verify the performance of the proposed algorithm. This article is not yet tagged | 2007 |
| | | Chughtai, S. S. | A High-Integrity Multivariable Robust Control With Application to a Process Control Rig read moreAbstract: This brief presents a systematic approach for the design of a robust decoupling precompensator using an approximate right inverse (ARI) of a system, where the problem of finding an ARI is presented as an $L_{2}$-gain minimization problem. Furthermore, new LMIs are presented to analyze worstcase $L_{2}$ -gain for an uncertain system. These LMIs use extra variables to eliminate product terms between system state matrices and the Lyapunov matrix. This elimination enables the use of a parameter dependent Lyapunov function in a systematic way. These LMIs are extended to synthesis both constant and dynamic precompensators as well. Using the synthesis and the analysis LMIs, a combined Genetic-LMI-Algorithm is also presented to find a suitable precompensator that achieves diagonal dominance for systems with input uncertainties. Some previously presented LMIs for pole clustering are also modified to make them compatible with newly presented LMIs. The proposed approach is applied to the design of a high integrity robust multiinput multioutput controller for a process control rig which consists of a temperature and a flow rate control loop. The system has an input uncertainty of about 20%. It is shown that the closed-loop system poses a high integrity while being robust with respect to input uncertainties. The controller is also applied to the real plant to verify that the proposed algorithm and the desired results are obtained. This article is not yet tagged | 2007 |
| | | Gao, Z. | High-Gain Estimator and Fault-Tolerant Design With Application to a Gas Turbine Dynamic System read moreAbstract: For dynamic systems with actuator faults, sensor faults, input disturbances, and measurement noises, a novel high-gain estimation technique is presented in this paper to estimate system states, actuator faults, and sensor faults simultaneously. The key idea is to represent faults as auxiliary system states so that a descriptor system representation can be formulated. By using the estimated state and fault signals, a fault-tolerant controller design approach is developed, where the closed-loop dynamic system can still be guaranteed to operate normally when actuator and sensor faults occur. It has been shown that in the proposed design framework, the actuator fault, sensor fault, input disturbance, and measurement noise can appear simultaneously and can be allowed to be in different bounded forms. Finally, the proposed algorithm is applied to the simulation study of a three-shaft gas turbine system and desired results have been obtained. This article is not yet tagged | 2007 |
| | | Steinfeld, R. | Lattice-Based Threshold Changeability for Standard Shamir Secret-Sharing Schemes read moreAbstract: We consider the problem of increasing the threshold parameter of a secret-sharing scheme after the setup (share distribution) phase, without further communication between the dealer and the shareholders. Previous solutions to this problem require one to start off with a nonstandard scheme designed specifically for this purpose, or to have communication between shareholders. In contrast, we show how to increase the threshold parameter of the standard Shamir secret-sharing scheme without communication between the shareholders. Our technique can thus be applied to existing Shamir schemes even if they were set up without consideration to future threshold increases. This article is not yet tagged | 2007 |
| | | Wang, H. | Dynamic Visual Tracking for Manipulators Using an Uncalibrated Fixed Camera read moreAbstract: This paper presents a new controller for controlling a number of feature points on a robot manipulator to trace desired trajectories specified on the image plane of a fixed camera. It is assumed that the intrinsic and extrinsic parameters of the camera are not calibrated. A new adaptive algorithm is developed to estimate the unknown parameters online, based on three original ideas. First, we use the pseudoinverse of the depth-independent interaction matrix to map the image errors onto the joint space of the manipulator. By eliminating the depths in the interaction matrix, we can linearly parameterize the closed-loop dynamics of the manipulator. Second, to guarantee the existence of the pseudoinverse, the adaptive algorithm introduces a potential force to drive the estimated parameters away from the values that result in a singular Jacobian matrix. Third, to ensure that the estimated parameters are convergent to their true values up to a scale, we combine the Slotine–Li method with an online algorithm for minimizing the error between the estimated projections and real image coordinates of the feature points. We have proved asymptotic convergence of the image errors to zero by the Lyapunov theory based on the nonlinear robot dynamics. Experiments have been carried out to verify the performance of the proposed controller. This article is not yet tagged | 2007 |
2006
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| | | Li, J. | Fingerprint indexing based on symmetrical measurement read moreAbstract: Sorry no abstract available for this article This article is not yet tagged | 2006 |
| | | Chi, W. | Ambient and High-Temperature Thermal Conductivity of Thermal Sprayed Coatings read moreAbstract: Sorry no abstract available for this article This article is not yet tagged | 2006 |
2005
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| | | MacEachren, A. M. | Enabling collaborative geoinformation access and decision-making through a natural, multimodal interface read moreAbstract: Sorry no abstract available for this article This article is not yet tagged | 2005 |
| | | Wu, P. -. | Compact and Broad-Band Millimeter-Wave Monolithic Transformer Balanced Mixers read moreAbstract: Three broad-band miniature monolithic transformer singly balanced diode mixers for operation in the microwave and millimeter-wave bands are reported in this paper. The coupled-line equivalent models are used to synthesize the initial design of these transformers up to 50 GHz. The first one is a broad-band spiral transformer mixer, and the second one is a 21-GHz Marchand-type transformer mixer. These two mixers with chip sizes around 0.29$hbox mm^2$exhibit bandwidths of 105% and 54.5%, respectively. We also propose a 30-GHz single-coiled transformer mixer, which has comparable performance with the first two mixers and reduced chip size. The single-coiled transformer mixer achieves a bandwidth of 100% with the chip size smaller than 0.25$hbox mm^2$. In order to save chip area, all these transformers provide broad-band matching to the diodes directly. To the authors' knowledge, these mixers achieve the widest bandwidths with the smallest chip sizes among all passive balanced mixers using monolithic-microwave integrated-circuit processes in dc–40-GHz frequency range. This article is not yet tagged | 2005 |
2002
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| | | Rauschert, I. | Designing a human-centered, multimodal GIS interface to support emergency management read moreAbstract: Geospatial information is critical to effective, collaborative deci-sion-making during emergency management situations; however conventional GIS are not suited for multi-user access and high-level abstract queries. Currently, decision makers do not always have the real time information they need; GIS analysts produce maps at the request of individual decision makers, often leading to overlapping requests with slow delivery times. In order to overcome these limitations, a paradigm shift in interface design for GIS is needed. The research reported upon here attempts to overcome analyst-driven, menu-controlled, keyboard and mouse operated GIS by designing a multimodal, multi-user GIS inter-face that puts geospatial data directly in the hands of decision makers. A large screen display is used for data visualization, and collaborative, multi-user interactions in emergency management are supported through voice and gesture recognition. Speech and gesture recognition is coupled with a knowledge-based dialogue management system for storing and retrieving geospatial data. This paper describes the first prototype and the insights gained for human-centered multimodal GIS interface design. This article is not yet tagged | 2002 |
1982
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| | | Wang, H. | Introduction to groundwater modeling : finite difference and finite element methods read moreAbstract: Sorry no abstract available for this article This article is not yet tagged | 1982 |
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