Quantization Watermarking for Joint Compression and Data Hiding Schemes

International audienceEnrichment and protection of JPEG2000 images is an important issue. Data hiding techniques are a good solution to solve these problems. In this context, we can consider the joint approach to introduce data hiding technique into JPEG2000 coding pipeline. Data hiding consists of imperceptibly altering multimedia content, to convey some information. This process is done in such a way that the hidden data is not perceptible to an observer. Digital watermarking is one type of data hiding. In addition to the imperceptibility and payload constraints, the watermark should be robust against a variety of manipulations or attacks. We focus on trellis coded quantization (TCQ) data hiding techniques and propose two JPEG2000 compression and data hiding schemes. The properties of TCQ quantization, defined in JPEG2000 part 2, are used to perform quantization and information embedding during the same time. The first scheme is designed for content description and management applications with the objective of achieving high payloads. The compression rate/imperceptibility/payload trade off is our main concern. The second joint scheme has been developed for robust watermarking and can have consequently many applications. We achieve the better imperceptibility/robustness trade off in the context of JPEG2000 compression. We provide some experimental results on the implementation of these two schemes

New Construction of a Chaotic Generator on the Lorenz Attractor

it be known that the chaotic phenomena can be obtained from relatively simple systems that are governed by a small number of variables. The system will then be deterministic, although its behaviour is unforeseeable. The chaotic generator hereby suggested is implemented under the 7.0 version of MATLAB software. It makes use exclusively, of the fundamental properties of chaotic systems; that are sensitivity to initial conditions and equations of strange attractor. All is done in order to set up systems with protected transmissions. As a matter of fact and in the long term, the unforeseeable behaviour of such systems is very much related to the extreme sensitivity of initials conditions. Another fundamental property is that the chaotic system is characterized by a strange attractor, within the space of state

Perceived risk of infection and death from COVID-19 among community members of low- and middle-income countries: A cross-sectional study [version 1; peer review: awaiting peer review]

Background: Risk perceptions of coronavirus disease 2019 (COVID-19) are considered important as they impact community health behaviors. The aim of this study was to determine the perceived risk of infection and death due to COVID-19 and to assess the factors associated with such risk perceptions among community members in low- and middle-income countries (LMICs) in Africa, Asia, and South America. Methods: An online cross-sectional study was conducted in 10 LMICs in Africa, Asia, and South America from February to May 2021. A questionnaire was utilized to assess the perceived risk of infection and death from COVID-19 and its plausible determinants. A logistic regression model was used to identify the factors associated with such risk perceptions. Results: A total of 1,646 responses were included in the analysis of the perceived risk of becoming infected and dying from COVID-19. Our data suggested that 36.4% of participants had a high perceived risk of COVID-19 infection, while only 22.4% had a perceived risk of dying from COVID-19. Being a woman, working in healthcare-related sectors, contracting pulmonary disease, knowing people in the immediate social environment who are or have been infected with COVID-19, as well as seeing or reading about individuals infected with COVID-19 on social media or TV were all associated with a higher perceived risk of becoming infected with COVID-19. In addition, being a woman, elderly, having heart disease and pulmonary disease, knowing people in the immediate social environment who are or have been infected with COVID-19, and seeing or reading about individuals infected with COVID-19 on social media or TV had a higher perceived risk of dying from COVID-19. Conclusions: The perceived risk of infection and death due to COVID-19 are relatively low among respondents; this suggests the need to conduct health campaigns to disseminate knowledge and information on the ongoing pandemic

Osteonecrosis of the jaw in patients traited by denosumab for malignant bone disease: Descriptive study on 9 cases

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Dynamic Performance and Sensitivity Investigation of a Narrow-band Frequency Detecting Microsensor

International audienceMicro-Electro-Mechanical Systems, or MEMS, are generally considered as micro devices consisting of combination of micro mechanical sensors and/or actuators in addition to microelectronic circuits [1]. MEMS-based sensors have been under steady development for the last several decades, and a variety of devices have been developed aiming numerous applications like accelerometers [2], gyroscopes [3], Magnetometers [4] and acoustic applications [5-6]. Acoustic microsystem devices have been focused by many teams in order to achieve various kinds of specific results. The main objectives of acoustic MEMS research have been the miniaturization of existing acoustic devices to a microscopic scale, saving cost, and to obtain acoustic sensing

Capacitance Link Effect Characterization in the Tapped On-Chip Planar Transformer

International audienceIn this paper, we present the theoretical model validation of an integrated planar transformer used in MEMS electrodynamic microsensor. The structure consists of two planar inductors: an outer fixed one and an inner suspended one. If the outer inductor is biased by an AC voltage, a mutual inductance link will be created between both inductors. We present an analytical approach to determine the induced voltage when applying an AC supply current to the outer inductor. In the paper, we discuss the difference between the analytical results with and the characterization. The difference is basically due to the coupling capacitance between the inner and the outer inductors and not only, as we expected, due to the mutual inductance. The introduction of the coupling capacitance, estimated to be around 1.7pF, to our simulation confirmed the measurement performed on the planar integrated transformer

Transport Properties of Mortars and Concretes Modified with Ground Granulated Blast Furnace Slag

ABSTRACT Mechanical characteristics and durability of ground granulated blast furnace slag cement composites depends on the hydraulic activity of the slag. Algerian Blast furnace slag is characterized by a quite slow reactivity. Porosity and transport properties of mixes containing up to 50% OPC replacement are compared and analyzed. Mechanical strength, pore size distribution and capillary water absorption are studied after 28 and 90 days of wet curing. The durability of blast furnace slag cement concrete is evaluated through nitrogen permeability and water penetration depth under pressure. First observations seem to indicate finer porosity and lower water absorption than with 100% CEM I 52.5 mortars. Moreover, lower permeabilities to nitrogen and water are also observed for 50% blast furnace slag substitution

Optimization of Induced Voltage From CMOSCompatible MEMS Electrodynamic Microphone With Coaxial Planar Inductances

International audienceThis paper presents an improved design of the electrodynamic CMOS-MEMS microphone. The studied microphone is based on two integrated concentric planar inductors, a fixed outer one and an inner one attached on a flexible vibrating diaphragm. First, the magnetic field, generated by the outerinductor, was evaluated. Unlike conventional electrodynamic microphones based on Faraday’s law, the induced voltage was found to be proportional to the product of the diaphragmdisplacement and its velocity. Even though the induced output voltage is in the range of a few microvolts, and its frequency is doubled compared to that of the incident acoustic wave. Thisresult pushed us to adjust and improve the basic principle of this kind of microphone by trying to generate a vertical downward shift of the microphone diaphragm while maintaining the COMScompatibility. The Lorentz force appears to be a possible alternative to the wafer bonding, as it will be automatically generated when we bias the inner inductor by a dc current. First, this paper shows that the induced voltage will be linear for a vertical fluctuation magnitude lower than 10 μm with an induced voltage in the range of several microvolts. Using the developed vertical offset technique, we show that induced voltages can be increased by a factor of 10 and the dynamic response of the electrodynamic microsensor will be appropriate for a use as a microphone