Noniterative Algorithms for Sensitivity Analysis Attacks

Sensitivity analysis attacks constitute a powerful family of watermark "removal" attacks. They exploit vulnerability in some watermarking protocols: the attacker's unlimited access to the watermark detector. This paper proposes a mathematical framework for designing sensitivity analysis attacks and focuses on additive spread-spectrum embedding schemes. The detectors under attack range in complexity from basic correlation detectors to normalized correlation detectors and maximum-likelihood (ML) detectors. The new algorithms precisely estimate and then eliminate the watermark from the watermarked signal. This is accomplished by exploiting geometric properties of the detection boundary and the information leaked by the detector. Several important extensions are presented, including the case of a partially unknown detection function, and the case of constrained detector inputs. In contrast with previous art, our algorithms are noniterative and require, at most, O(n) detection operations in order to precisely estimate the watermark, where n is the dimension of the signal. The cost of each detection operation is O(n); hence, the algorithms can be executed in quadratic time. The method is illustrated with an application to image watermarking using an ML detector based on a generalized Gaussian model for images     

Photodetectors based on amorphous and microcrystalline silicon

p-i-n diodes based on amorphous and microcrystalline silicon are used for different applications like sensors or solar cells. However, their long-term stability and dynamic behavior are still under discussion. Therefore, the optical properties of both types of diodes were investigated by a comparative study. The long-term stability of non-encapsulated devices was tested by means of light soaking, damp heat testing and high-temperature treatment of up to 2000 h. The dynamic properties of the thin-film silicon photodetectors were studied by measuring and analysing the admittance under different bias conditions.     

Influence of external mechanical loadings (creep,fatigue) on oxygen diffusion during nickel oxidation

This study deals with the influence of various mechanical loadings (fatigue, creep, creep-fatigue) on oxygen diffusion in a particular system, oxidizing nickel. A distinction between the behavior of the oxide layer and underlying nickel was noted during the first step of oxidation at 550°C, in P_{O 2}=1 atm. Mechanical loading causes a decrease of the oxygen mobility through the oxide scale (factor of 10³). The oxide thicknesses on nickel undergoing mechanical loadings are different than for an unloaded sample, due to distinct contributions of the oxygen and nickel fluxes in the growing oxide. In the substrate, the ingress of oxygen becomes easier with a constant tensile load (creep). The intergranular-oxygen diffusion coefficient, D_i, is increased by a factor of 10² with respect to other samples. In creep, oxygen diffusion takes place along grain boundaries of a structure with smaller grains than in unstrained Ni. A short fatigue period during creep-fatigue decreases the sensitivity of nickel to intergranular-oxygen diffusion.     

Development of a database: DACTARI for a radiotoxic element ranking methodology

Dosimetric impact studies aim at evaluating potential radiological effects of chronic or acute releases from nuclear facilities. A methodology for ranking radionuclides (RN) in terms of their health-related impact on the human population was first developed at CEA with specific criteria for each RN that could be applied to a variety of situations. It is based, in particular, on applying physico-chemical criteria to the complete RN inventory (present in the release or in the source term) and on applying norms related to radiation protection and chemical toxicology. The initial step consisted in identifying and collecting data necessary to apply the methodology, with reference to a previous database of long-lived radionuclides (LLRN, with half-lives ranging from 30 to 10(14) y) containing 95 radionuclides. The initial results have allowed us to identify missing data and revealed the need to complete the study for both toxic and radiotoxic aspects. This led us to the next step, developing a specific database, DAtabase for Chemical Toxicity and Radiotoxicity Assessment of RadIonuclides (DACTARI), to collect data on chemical toxicity and radiotoxicity, including acute or chronic toxicity, the chemical form of the compounds, the contamination route (ingestion, inhalation), lethal doses, target organs, intestinal and maternal-foetal transfer, drinking water guidelines and the mutagenic and carcinogenic properties.     

Total and partial pressure measurements for the sulphur–iodine thermochemical cycle

First results on the measurement of total and partial pressures over the ternary system HI–_I2–_H2O$\mathrm{HI}–{\mathrm{I}}_2–{\mathrm{H}}_2\mathrm{O}$ are reported. Using original optical online measurements, data on the gas phase speciation are obtained which will help to scale and optimize the reactive distillation column we promote for the HI section of the sulphur–iodine cycle.     

Landfill leachate treatment: Review and opportunity

In most countries, sanitary landfilling is nowadays the most common way to eliminate municipal solid wastes (MSW). In spite of many advantages, generation of heavily polluted leachates, presenting significant variations in both volumetric flow and chemical composition, constitutes a major drawback. Year after year, the recognition of landfill leachate impact on environment has forced authorities to fix more and more stringent requirements for pollution control. This paper is a review of landfill leachate treatments. After the state of art, a discussion put in light an opportunity and some results of the treatment process performances are given. Advantages and drawbacks of the various treatments are discussed under the items: (a) leachate transfer, (b) biodegradation, (c) chemical and physical methods and (d) membrane processes. Several tables permit to review and summarize each treatment efficiency depending on operating conditions. Finally, considering the hardening of the standards of rejection, conventional landfill leachate treatment plants appear under-dimensioned or do not allow to reach the specifications required by the legislator. So that, new technologies or conventional ones improvements have been developed and tried to be financially attractive. Today, the use of membrane technologies, more especially reverse osmosis (RO), either as a main step in a landfill leachate treatment chain or as single post-treatment step has shown to be an indispensable means of achieving purification.     

Graph-Based Synthesis for Skin Micro Wrinkles

We present a novel graph-based simulation approach for generating micro wrinkle geometry on human skin, which can easily scale up to the micro-meter range and millions of wrinkles. The simulation first samples pores on the skin and treats them as nodes in a graph. These nodes are then connected and the resulting edges become candidate wrinkles. An iterative optimization inspired by pedestrian trail formation is then used to assign weights to those edges, i.e., to carve out the wrinkles. Finally, we convert the graph to a detailed skin displacement map using novel shape functions implemented in graphics shaders. Our simulation and displacement map creation steps expose fine controls over the appearance at real-time framerates suitable for interactive exploration and design. We demonstrate the effectiveness of the generated wrinkles by enhancing state-of-art 3D reconstructions of real human subjects with simulated micro wrinkles, and furthermore propose an artist-driven design flow for adding micro wrinkles to fictional characters.     

Development of a Measure Cell to Assess by Amperometry Dissolved Oxygen in Vegetable Oils

Dissolved oxygen in vegetable oils is an important component of oil degradation over time. Various methods for the determination of dissolved oxygen in oils are proposed in the literature leading to very variable results. An amperometric method associated with a cell of measurement in dynamic mode makes it possible to determine the conditions of stability of the measurements of the relative dissolved oxygen concentration (RDOC, mg L⁻¹) and the electrolysis current intensity (ECI) (nA) in seed oils and virgin olive oils. The effects of oxygenation/deoxygenation time and temperature on RDOC measurements are investigated. For virgin olive oils, the RDOC in bottles closed for eight weeks varies from 0 to 0.9 mg L⁻¹. The nature of the fruitiness and the filtration of the oils have no influence on the RDOC. The monitoring of RDOC and ECI during the flow of virgin olive oil in a column open to air, simulating an industrial tank, shows differences in dissolved oxygen concentration due to a faster flow of oil in the center of the column than at the walls. This result is validated by a similar experiment with nitrogen inerting the column and by a numerical simulation. Practical applications: Knowledge of the oxygen dissolved in vegetable oils is an important factor in limiting the autoxidation phenomenon to increase their shelf life. The development of a cell for measuring the relative dissolved oxygen concentration (RDOC) in vegetable oils and its conditions of use, provides a tool for the RDOC applicable to the different stages of the manufacturing process and during storage or packaging. The RDOC measurement is particularly useful during long storage in tanks whether inerted or not.     

Direct microwave heating of alumina for different densities: experimental and numerical thermal analysis

Microwave heating of pure alumina is studied experimentally and numerically, in a 2.45 GHz single-mode cavity, for different density levels. Even considering a constant incident power, the results show a complex evolution of the alumina temperature: first a two-step increase, then a maximum, and finally a cooling stage. In addition, a density dependence of the heating efficiency is observed: a more efficient heating occurs for lower densities. Using the effective medium approximation (EMA) to derive the physical data as functions of density, the numerical simulations are in contradiction with the experiments, proving that the EMA approach is not able to correctly predict the imaginary part of the permittivity. Furthermore, the simulations do not accurately describe the first moments of the heating, nor the long-term evolution of the temperature (cooling). We then explain the origin of this discrepancy: the need to adjust the movable stub on the one hand, and to account for heat exchange between the cavity and its surroundings on the other.