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arXiv 2025年

作者： Zhang, Ni Wang, Kunlun Chen, Wen Xu, Jing Li, Yonghui Nallanathan, Arumugam Shanghai Key Laboratory of Multidimensional Information Processing East China Normal University Shanghai200241 China School of Communication and Electronic Engineering East China Normal University Shanghai200241 China Department of Electronic Engineering Shanghai Jiao Tong University Shanghai200240 China School of Electrical and Information Engineering The University of Sydney Australia School of Electronic Engineering and Computer Science Queen Mary University of London LondonE1 4NS United Kingdom

In this paper, we propose a Satellite-Terrestrial Integrated Network (STIN) assisted vehicular multi-tier distributed computing (VMDC) system leveraging hybrid terahertz (THz) and radio frequency (RF) communication technologies. Task offloading for satellite edge computing is enabled by THz communication using the orthogonal frequency division multiple access (OFDMA) technique. For terrestrial edge computing, we employ non-orthogonal multiple access (NOMA) and vehicle clustering to realize task offloading. We formulate a non-convex optimization problem aimed at maximizing computation efficiency by jointly optimizing bandwidth allocation, task allocation, subchannelvehicle matching and power allocation. To address this non-convex optimization problem, we decompose the original problem into four sub-problems and solve them using an alternating iterative optimization approach. For the subproblem of task allocation, we solve it by linear programming. To solve the subproblem of sub-channel allocation, we exploit many-to-one matching theory to obtain the result. The subproblem of bandwidth allocation of OFDMA and the subproblem of power allocation of NOMA are solved by quadratic transformation method. Finally, the simulation results show that our proposed scheme significantly enhances the computation efficiency of the STIN-based VMDC system compared with the benchmark schemes. Copyright © 2025, The Authors. All rights reserved.

关键词： Convex optimization

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SPECTRAL CORRELATION OF MODULATED SIGNALS - .1. ANALOG MODULATION

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IEEE TRANSACTIONS ON COMMUNICATIONS 1987年第6期35卷 584-594页

作者： GARDNER, WA Signal and Image Processing Laboratory Department of Electrical and Computer Engineering University of California Davis CA USA

The importance of the concept of cyclostationarity in design and analysis of signal detectors, synchronizers, and extractors in communication systems is briefly discussed, and the central role of spectral correlation, in the characterization of random processes that are cyclostationary in the wide sense, is explained. A spectral correlation function that is a generalization of the power spectral density function is described, and a corresponding generalization of the Wiener-Khinchine relation and several other fundamental spectral correlation relations also are described. Explicit formulas for the spectral correlation function for various types of analog-modulated signals are derived. This includes pulse and carrier amplitude modulation, quadrature amplitude carrier modulation, and phase and frequency carrier modulation. To illustrate the differing spectral correlation characteristics of different modulation types, the magnitudes of the spectral correlation functions are graphed or described in graphical terms as the heights of surfaces above a bifrequency plane.

关键词： Pulse modulation Amplitude modulation Phase modulation Quadrature amplitude modulation Signal design Signal analysis Signal processing Signal detection Detectors Frequency synchronization

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RECURSIVE BLOCK CODING - A NEW APPROACH TO TRANSFORM CODING

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IEEE TRANSACTIONS ON COMMUNICATIONS 1986年第2期34卷 161-179页

作者： FARRELLE, PM JAIN, AK Signal and Image Processing Laboratory Department of Electrical and Computer Engineering University of California Davis CA USA

The concept of fast KL transform coding introduced earlier [7], [8] for first-order Markov processes and certain random fields has been extended to higher order autoregressive (AR) sequences and practical images yielding what we call recursive block coding (RBC) algorithms. In general, the rate-distortion performance for these algorithms is significantly superior to that of the conventional block KL transform algorithm. Moreover, these algorithms permit the use of small size transforms, thereby removing the need for fast transforms and making the hardware implementation of such coders more appealing. This improved performance has been verified for practical image data and results in suppression of the block-boundary effect commonly observed in traditional transform coding techniques. This is illustrated by comparing RBC with cosine transform coding using both one- and twodimensional algorithms. Examples of RBC encoded images at various rates are given.

关键词： Transform coding Karhunen-Loeve transforms Block codes Data compression Image coding Signal processing Image processing Bit rate Markov processes Rate-distortion

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Coding of video-conference stereo image sequences using 3D models

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SIGNAL processing-IMAGE COMMUNICATION 1997年第2期9卷 125-135页

作者： Malassiotis, S Strintzis, MG Information Processing Laboratory Department of Electrical and Computer Engineering University of Thessaloniki Thessaloniki 540 06 Greece

In this paper we propose an object-based stereo image coding algorithm. The algorithm relies on modeling of the object structure using 3D wire-frame models, and motion estimation using globally rigid and locally deformable motion models. Algorithms for the estimation of motion and structure parameters from stereo images are described. Motion parameters are used to construct predicted images at subsequent time instances by mapping the image texture on the object surface. Coding of object parameters, appearing background regions and prediction errors is investigated and experimental results with video-conference scenes are presented. The proposed algorithm is very efficient for applications like stereoscopic video transmission, and is especially suited to advanced applications such as generation and transmission of intermediate views for multiview receiver systems, as well as applications in which an object-wise editing of the bit-stream is required, such as video-production using preanalysed scenes or virtual reality applications.

关键词： stereo synthetic and natural hybrid coding 3D model coding

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Model-based joint motion and structure estimation from stereo images

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computer VISION AND IMAGE UNDERSTANDING 1997年第1期65卷 79-94页

作者： Malassiotis, S Strintzis, MG Information Processing Laboratory Department of Electrical and Computer Engineering University of Thessaloniki Thessaloniki 540 06 Greece

In this paper we integrate motion and structure estimation in order to exploit their coherence. We propose an algorithm that uses models for object surfaces and their motion and estimates the model parameters using the image intensity matching criterion. The visible scene surface is represented with a parametrically deformable, spatially adaptive, wireframe model. Object motion is first modeled using the well-known rigid motion assumption along with the quaternion rotation representation. Nonrigid motion modeling using the finite element technique is also investigated as an alternative to rigid motion modeling or as a refinement of it. A functional containing image matching and surface smoothness constraints is minimized with respect to the unknown model parameters. A discontinuity detection scheme allowing deactivation of smoothness constraints across object boundaries, is investigated. A regularization scheme using a coarse to fine strategy is employed. (C) 1997 Academic Press.

关键词： Stereo vision

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Prescribed Performance Control for a Nonlinear System With Actuator Saturation via Anti-Windup Design

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IEEE Transactions on Circuits and Systems I: Regular Papers 2025年

作者： Lai, Wenxin Li, Yuanlong Lin, Zongli Shanghai Jiao Tong University Department of Automation Shanghai 200240 China Ministry of Education of China Key Laboratory of System Control and Information Processing Shanghai 200240 China Shanghai Engineering Research Center of Intelligent Control and Management Shanghai 200240 China University of Virginia Charles L. Brown Department of Electrical and Computer Engineering Charlottesville 22904 VA United States

In this paper, within the prescribed performance control framework, we revisit the output tracking problem of a nonlinear system with input saturation, user-specified performance and external disturbances. To handle the intrinsic conflict between actuator saturation and performance requirements, we introduce a novel auxiliary system, which is driven by an artificial saturation nonlinearity, to generate modification signals for relaxing the prescribed performance functions. To further alleviate the adverse effects caused by actuator saturation, we incorporate a new performance-based anti-windup compensator into the control framework. In particular, the auxiliary system is designed to adjust the external performance requirements, and the anti-windup compensator is used for improving the internal saturation handling capability. Moreover, we employ a predetermined weighting coefficient to balance between the auxiliary system and the anti-windup compensator for better control performance. To deal with external disturbances, we construct a series of disturbance observers. With the help of dynamic surface control strategies, we develop a state-feedback control law. Theoretical analysis establishes the boundedness of all signals. Finally, an academic example and a tunnel diode circuit system are provided to demonstrate the effectiveness of our control strategy. © 2004-2012 IEEE.

关键词： activation mechanism Actuator saturation anti-windup disturbance observers prescribed performance reference tracking

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SPECTRAL CORRELATION OF MODULATED SIGNALS .2. DIGITAL MODULATION

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IEEE TRANSACTIONS ON COMMUNICATIONS 1987年第6期35卷 595-601页

作者： GARDNER, WA BROWN, WA CHEN, CK Signal and Image Processing Laboratory Department of Electrical and Computer Engineering University of California Davis CA USA

As a continuation of Part I, the spectral correlation function is presented for a variety of types of digitally modulated signals. These include digital pulse-amplitude, pulse-width, and pulse-position modulation, and various types of phase-shift keying and frequency-shift keying. The magnitudes of the spectral correlation functions are graphed as the heights of surfaces above a bifrequency plane, and these graphs are used as visual aids for comparison and contrast of the spectral correlation properties of different modulation types.

关键词： Digital modulation Space vector pulse width modulation Signal processing Pulse modulation Phase shift keying Frequency shift keying Pulse width modulation Filters Matrices Parameter estimation

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INTERFERENCE-TOLERANT TIME-DIFFERENCE-OF-ARRIVAL ESTIMATION FOR MODULATED SIGNALS

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IEEE TRANSACTIONS ON ACOUSTICS SPEECH AND SIGNAL processing 1988年第9期36卷 1385-1395页

作者： GARDNER, WA CHEN, CK Signal and Image Processing Laboratory Department of Electrical Engineering and Computer Science University of California슠Davis Davis CA USA Signal and Image Processing Laboratory Department of Electrical Engineering and Computer Science University of California Davis Davis CA USA

A method for estimation of the difference in the times of arrival of wavefronts of two separate sensors is introduced. The method, called SPECCORR, exploits the spectral correlation property, called spectral coherence, that essentially all modulated signals exhibit to obtain estimates that are highly tolerant to severely corruptive noise and interference. This tolerance is explained theoretically and demonstrated with simulations.< >

关键词： Interference Time difference of arrival Noise measurement Narrowband Autocorrelation Direction of arrival estimation Antenna measurements Design methodology Signal design

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Generative AI-driven Cross-layer Covert Communication: Fundamentals, Framework and Case Study

arXiv

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arXiv 2025年

作者： Liu, Tianhao Liu, Jiqiang Zhang, Tao Wang, Jian Wang, Jiacheng Kang, Jiawen Niyato, Dusit Mao, Shiwen School of Cyberspace Science and Technology Beijing Jiaotong University Beijing100044 China Beijing Key Laboratory of Security and Privacy in Intelligent Transportation Beijing Jiaotong University Beijing100045 China School of Computer Science and Engineering Nanyang Technological University Singapore639798 Singapore School of Automation Guangdong University of Technology Key Laboratory of Intelligent Information Processing and System Integration of IoT Ministry of Education Guangzhou510006 China Guangdong-HongKong-Macao Joint Laboratory for Smart Discrete Manufacturing Guangzhou510006 China Department of Electrical and Computer Engineering Auburn University AuburnAL36849-5201 United States

Ensuring end-to-end cross-layer communication security in military networks by selecting covert schemes between nodes is a key solution for military communication security. With the development of communication technology, covert communication has expanded from the physical layer to the network and application layers, utilizing methods such as artificial noise, private networks, and semantic coding to transmit secret messages. However, as adversaries continuously eavesdrop on specific communication channels, the accumulation of sufficient data may reveal underlying patterns that influence concealment, and establishing a cross-layer covert communication mechanism emerges as an effective strategy to mitigate these regulatory challenges. In this article, we first survey the communication security solution based on covert communication, specifically targeting three typical scenarios: device-to-device, private network communication, and public network communication, and analyze their application scopes. Furthermore, we propose an end-to-end cross-layer covert communication scheme driven by Generative Artificial Intelligence (GenAI), highlighting challenges and their solutions. Additionally, a case study is conducted using diffusion reinforcement learning to sovle cloud edge internet of things cross-layer secure communication. © 2025, CC BY.

关键词： Generative adversarial networks

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Network and data security design for telemedicine applications

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MEDICAL INFORMATICS 1997年第2期22卷 133-142页

作者： Makris, L Argiriou, T Strintzis, NG Information Processing Laboratory Electrical and Computer Engineering Department Aristotle University of Thessaloniki Thessaloniki 540 06 Greece

The maturing of telecommunication technologies has ushered in a whole new era of applications and services in the health care environment. Teleworking, teleconsultation, multimedia conferencing and medical data distribution are rapidly becoming commonplace in clinical practice. As a result, a set of problems arises, concerning data confidentiality and integrity. Public computer networks, such as the emerging ISDN technology, are vulnerable to eavesdropping. Therefore it is important for telemedicine applications to employ end-re-end encryption mechanisms securing the data channel from unauthorized access or modification. We propose a network access and encryption system that is both economical and easily implemented for integration in developing or existing applications, using well-known and thoroughly tested encryption algorithms. Public-key cryptography is used for session-key exchange, while symmetric algorithms are used for bulk encryption. Mechanisms for session-key generation and exchange are also provided.

关键词： data communications data security encryption

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