REAL-TIME VIDEO WATERMARKING FOR COPYRIGHT PROTECTION BASED ON HUMAN PERCEPTION

There is a need for real-time copyright logo insertion in emerging applications, such as Internet protocol television (IPTV). This situation arises in IP-TV and digital TV broadcasting when video residing in a server has to be broadcast by different stations and under different broadcasting rights. Embedded systems that are involved in broadcasting need to have embedded copyright protection. Existing works are targeted towards invisible watermarking, not useful for logo insertion. MPEG-4 is the mainstream exchangeable video format in the Internet today because it has higher and flexible compression rate, lower bit rate, and higher efficiency while superior visual quality.The main steps for MPEG-4 are color space conversion and sampling, DCT and its inverse (IDCT), quantization, zigzag scanning, motion estimation, and entropy coding. In this work a watermarking algorithm that performs the broadcaster\u27s logo insertion as watermark in the DCT domain is been presented. The robustness of DCT watermarking arises from the fact that if an attack tries to remove watermarking at mid frequencies, it will risk degrading the fidelity of the image\video because some perceptive details are at mid frequencies. The suggested methods has implemented in matlab

Fluctuation-based Adaptive Structured Pruning for Large Language Models

Network Pruning is a promising way to address the huge computing resource demands of the deployment and inference of Large Language Models (LLMs). Retraining-free is important for LLMs' pruning methods. However, almost all of the existing retraining-free pruning approaches for LLMs focus on unstructured pruning, which requires specific hardware support for acceleration. In this paper, we propose a novel retraining-free structured pruning framework for LLMs, named FLAP (FLuctuation-based Adaptive Structured Pruning). It is hardware-friendly by effectively reducing storage and enhancing inference speed. For effective structured pruning of LLMs, we highlight three critical elements that demand the utmost attention: formulating structured importance metrics, adaptively searching the global compressed model, and implementing compensation mechanisms to mitigate performance loss. First, FLAP determines whether the output feature map is easily recoverable when a column of weight is removed, based on the fluctuation pruning metric. Then it standardizes the importance scores to adaptively determine the global compressed model structure. At last, FLAP adds additional bias terms to recover the output feature maps using the baseline values. We thoroughly evaluate our approach on a variety of language benchmarks. Without any retraining, our method significantly outperforms the state-of-the-art methods, including LLM-Pruner and the extension of Wanda in structured pruning. The code is released at https://github.com/CASIA-IVA-Lab/FLAP.Comment: Accepted to AAAI 202

Límites de esbeltez basados en prestaciones para vigas de hormigón armado para el control de deformaciones y el control de tensiones en la armadura

Due to the complex deformational behavior of cracked RC members, an effective way to ensure the fulfilment of the SLS is to limit the slenderness ratio l/d of the element. In this study, the deformation slenderness limit concept is generalized to incorporate crack width limitations. The proposed slenderness limits are compared with those derived from non-linear time-dependent analysis and also with those obtained using the EC2 method of deflections interpolation. Very good approximation and low scatter has been obtained showing that the proposed slenderness limits are a useful tool for performance-based design of RC structures.The financial support provided by the Spanish Ministry of Economy and Competitiveness (MINECO) and the European Funds for Regional Development (FEDER), through the Research projects: BIA2015-64672-C4-1-R and BIA2017-84975-C2-2-P and through the Excellence network BIA2015-71484-REDTPostprint (published version

Modeling the homogenization of a heterogeneous granular bentonite mixture

A hydro-mechanical model of a heterogeneous granular bentonite mixture is presented based on discretization into a finite number of “bentonite units”, systems in which “megapores” are considered between bentonite grains, which, in turn, contain micro- and macropores. A macroscopic approach is used, where pore levels are associated with superposed homogeneous continua. Mixture heterogeneity is incorporated into the model considering the potentially very different percentage of megapores and grains in adjacent bentonite unit pairs. Mechanical contact is therefore affected, so a strategy is proposed based on porosity values, controlling deformability by the most deformable of the two units in contact. The constitutive formulation was implemented on a numerical solver to simulate a confined hydration test on a granular bentonite mixture with a notable initial local heterogeneity. The reproduced experimental evolution of the swelling pressure, relative humidity distribution, and water inflow was satisfactory. Porosity variation data were synthesized through histograms, describing not only the variation of the maximum and minimum porosity values but also the evolution of the porosity distribution in the mixture. This provides a quantitative description of the homogenization process, allowing an assessment of its scope and technological interest.This work is part of the project PID2020-118291RB-I00 funded by MCIN/AEI/ 10.13039/501100011033. This work was also supported by a ‘Margarita Salas’ grant from Ministerio de Universidades – Gobierno de España, awarded to Joel Torres-Serra.Peer ReviewedPostprint (published version

Seismic performance of innovative double layer space shear wall

Various kinds of seismic structural systems could not completely satisfy engineers due to excessive rigidity and low ductility. Then engineers innovate advanced ductile structural systems like viscous elastic dampers to dissipate earthquake forces and insulate important structural elements in safe zone; however these systems have not been pervasive in construction industry due to high production cost. Indeed, optimization of stiffness, ductility, and construction cost are the major challenges facing the engineering profession in designing a perfect lateral system. This research introduces Space Shear Wall (SpaSW), as an innovative earthquake resistant system for structures and evaluates its feasibility and seismic performance through three-dimensional linear and nonlinear-static, lineardynamic, and finite element analysis carried out by ETABS and ANSYS program. Space shear wall is defined as a double-layer diagonal space frame structure with ball joints vertically used as infill wall. The comparative study between SpaSW and steel bracing used in typical low to high-rise structures expressed that structural drift of SpaSW is slightly higher than steel bracing. However the ductility, energy dissipation, members’ stress and distribution of earthquake force in SpaSW are significantly better than typical steel bracing. In addition, failure mechanism of SpaSW were favourable due to its gradual process through many ball joints. Moreover, lightness, industrialization, maintainability and reparability, compatibility with architectural considerations, low cost, simple and fast fabrication are other realized advantages. Developing this concept would be considered in the future studies through optimization of material, grid patterns, connection, and additional dampers

Structural Behaviour of Blast Loaded Hybrid Systems

Currently, in the military and civilian fields, there is an increasing demand for using hybrid systems, which are manmade structural systems combining two or more distinct materials. By carefully studying and designing such kind of structural systems, one can take advantage of heterogeneity of the structure, thus significantly improving the overall structural performance. Hence, the demand for robust analytical and numerical models to predict blast performance of such system has become more important. The primary aim of the present research is to investigate and understand the structural behaviour of several hybrid systems under extreme dynamic loads and to propose concepts for optimisation. Three types of hybrid systems have been studied, improved and their performance has been validated. They are the metal-to-composite hybrid joints, sandwich panels, and the metamaterial. Analytical, numerical and experimental studies have been conducted to analyse the structural behaviour of hybrid joints and sandwich panels under transient high intensity dynamic loading, in order to ensure these systems possess the desired capacity, designed strength, and robustness. Therefore, they are able to resist not only static loadings but also shocks induced by various explosions. For frequency analysis purposes, the perforated hybrid joints and metamaterials have been considered as a 2D lattice. The primitive cell (unit cell) of the lattice is formulated in the Fourier space (k-space) and studied using the Floquet-Bloch’s principle to investigate the attenuation-free shock response characteristics. Plane wave propagation in the hybrid system is thus investigated by constructing the first Brillouin zone and extracting the band structure diagram. As another case for a hybrid system, the structural performance of a circular sandwich panel with symmetric through-thickness architecture subjected to a pulse loading of arbitrary temporal and spatially uniform distribution (UDL) has been investigated by using the third order shear deformation theory. Based on the Hamilton’s principle, the governing partial differential equations (PDE’s) are derived. By applying the weak form Galerkin’s method of weighted residuals, the PDE’s are transformed into ODE’s. By solving the ODE’s with their boundary and initial conditions, results show that there is a strong correlation with finite element results obtained from ABAQUS 6.9. The third-order shear deformation theory allows for accurate assessment of out-of -plane shear in the core where the failure usually occurs. Due to the fact that core of a sandwich panel is more often to be the weakest link, a remedy must sought, e.g. employing additional core layers, to improve its performance. Dynamic response of four circular sandwich panel constructions with different proposed core designs under global and local blast loading conditions has been investigated. Numerical finite element (FE) models have been set up to study the effect of additional core inter-layers on blast resistance enhancement of these sandwich panels. A ductile elastomeric layer of polyurea, and a fairly compressible Divinycell-H200 foam layer have been selected as the additional core inter-layers and have been placed in different arrangements to protect the core of the standard sandwich panels, and maximise overall blast resistance. Comparison of specific kinetic and strain energies shows the effect of additional core layers on blast energy absorption of a sandwich system. The study shows the improvement in shear failure prevention in the core as a result of the use of additional core layers. One qualitative 2DoF system with a viscoelastic spring element representing the integral effects of sacrificial additional core inter-layers and a nonlinear spring representing the stiffness of the conventional sandwich system; and a similar qualitative SDoF model of a conventional sandwich panel have been developed for dynamic analysis. The conclusions drawn from the numerical tests are confirmed by the output of this analysis. The results of this research work give a better understanding of the performance of some generic hybrid systems under blast, which allows the optimised hybrid system to be more confidently designed and should be able to fill the gap in the currently growing demand for high strength, light weight, reliable hybrid systems in various civilian and military industries

Performance-based slenderness limits for deformations and crack control of reinforced concrete flexural members

The use of high strength materials allows flexural members to resist the design loads or to cover long spans with a reduced depth. However, the strict cross section dimensions and reinforcement amount required in ULS are often insufficient to satisfy the serviceability limit states. Due to the complexity associated to a rigorous computation of deflections and cracks width in cracked RC members along their service life, an effective way to ensure the satisfaction of the SLS is to limit the slenderness ratio l/d of the element. In the present study, the slenderness limit concept, previously used for deflection control, is generalized to incorporate the crack width limitations in the framework of structural performance-based design. Equations for slenderness limits incorporating the main parameters influencing the service behaviour of RC members are derived. Cracking and long-term effects are accounted for through simplified coefficients derived from structural concrete mechanics and experimental observations. The proposed slenderness limits are compared with those derived from a numerical non-linear time-dependent analysis for two case studies, and also with those obtained using the EC2 procedure for deflection calculation in terms of constant applied load and constant reinforcement strain. Very good results have been obtained in terms of low errors and scatter, showing that the proposed slenderness limits are a useful tool for performance-based design of RC structures.Peer ReviewedPostprint (author's final draft