Data-Hiding Codes

This tutorial paper reviews the theory and design of codes for hiding or embedding information in signals such as images, video, audio, graphics,and text. Such codes have also been called watermarking codes; they can be used in a variety of applications, including copyright protection for digital media, content authentication, media forensics, data binding, and covert communications. Some of these applications imply the presence of an adversary attempting to disrupt the transmission of information to the receiver; other applications involve a noisy, generally unknown, communication channel. Our focus is on the mathematical models, fundamental principles, and code design techniques that are applicable to data hiding. The approach draws from basic concepts in information theory, coding theory, game theory, and signal processing,and is illustrated with applications to the problem of hiding data in images.     

Information-theoretic bounds on target recognition performancebased on degraded image data

This paper derives bounds on the performance of statistical object recognition systems, wherein an image of a target is observed by a remote sensor. Detection and recognition problems are modeled as composite hypothesis testing problems involving nuisance parameters. We develop information-theoretic performance bounds on target recognition based on statistical models for sensors and data, and examine conditions under which these bounds are tight. In particular, we examine the validity of asymptotic approximations to probability of error in such imaging problems. Problems involving Gaussian, Poisson, and multiplicative noise, and random pixel deletions are considered, as well as least-favorable Gaussian clutter. A sixth application involving compressed sensor image data is considered in some detail. This study provides a systematic and computationally attractive framework for analytically characterizing target recognition performance under complicated, non-Gaussian models and optimizing system parameters     

Assessing the inhibitory account of retrieval-induced forgetting with implicit-memory tests.

Five experiments examined whether retrieval-induced-forgetting effects are observed for implicit tests of memory. In each experiment participants first studied category- exemplar paired associates, then practiced retrieval for a subset of items from a subset of categories before finally completing memory tests for all the studied items. In standard fashion, inhibition was measured as the performance difference of unpracticed items from practiced categories and unpracticed items from unpracticed categories. Across the 5 experiments poorer performance for unpracticed items was seen in conceptual implicit memory (category generation and category matching) but not in perceptual implicit memory (stem completion, perceptual identification). Thus, retrieval-induced-forgetting effects are limited to tests of conceptual memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparative quantitative analysis of sucrose and related compounds using ion exchange and reverse phase chromatographic methods

Two analytical methods of sugar determination, namely ion exchange chromatography on an anionic resin coupled with electrochemical detection, and reverse phase chromatography on Nucleosil-NH2 resin equipped with a light scattering detector were tested and compared as regards their rapidity, sensitivity and accuracy with sucrose, fructose, glucose, raffinose, maltose, arabinose, fucose, rhamnose and xylose. Excellent resolution and highly reproducible results were obtained in both cases. Greater sensitivity up to the picomolar range was possible however only with ion exchange chromatography. Reverse phase chromatography was successfully applied to the time course of sucrose hydrolysis under chemical (acid) and enzymatic (invertase) conditions. The hydrolysis was monitored by determining sucrose degradation and the corresponding formation of glucose and fructose.     

Theory and design of signal-adapted FIR paraunitary filter banks

We study the design of signal-adapted FIR paraunitary filter banks, using energy compaction as the adaptation criterion. We present some important properties that globally optimal solutions to this optimization problem satisfy. In particular, we show that the optimal filters in the first channel of the filter bank are spectral factors of the solution to a linear semi-infinite programming (SIP) problem. The remaining filters are related to the first through a matrix eigenvector decomposition. We discuss uniqueness and sensitivity issues. The SIP problem is solved using a discretization method and a standard simplex algorithm. We also show how regularity constraints may be incorporated into the design problem to obtain globally optimal (in the energy compaction sense) filter banks with specified regularity. We also consider a problem in which the polyphase matrix implementation of the filter bank is constrained to be DCT based. Such constraints may also be incorporated into our optimization algorithm; therefore, we are able to obtain globally optimal filter banks subject to regularity and/or computational complexity constraints. Numerous experiments are presented to illustrate the main features that distinguish adapted and nonadapted filters, as well as the effects of the various constraints. The conjecture that energy compaction and coding gain optimization are equivalent design criteria is shown not to hold for FIR filter banks     

Treatment of gas containing hydrophobic VOCs by a hybrid absorption-pervaporation process: The case of toluene

The work focuses on a hybrid process for treating air charged with a hydrophobic volatile organic compound (VOC), coupling an absorption process with membrane pervaporation in order to reuse the absorbent. Toluene was chosen as the target VOC. Four topics were investigated: choice of the absorbent, hydrodynamics and mass transfer in a packed column, regeneration by pervaporation and finally analysis of the coupling of the two processes. In a previous study, 7 absorbents were compared with regard to experimental data (gas-liquid equilibrium constants, viscosity) and data from the literature. Di(2-ethylhexyl) adipate (DEHA) was shown to be the most suitable absorbent. In the first part of this work, experiments in a packed column showed that the viscosity of DEHA led to an increase in pressure drop, which nevertheless remained at a reasonable level. Mass transfer experiments were performed and kinetic constants (K_La) calculated. It was proven than washing with DEHA is highly efficient for toluene absorption. The most innovative part of the work is the regeneration of used absorbent by pervaporation. PDMS was chosen as the active membrane layer. Pervaporation flow rates of toluene were measured for the DEHA-toluene solutions corresponding to column foot concentrations. Transfer resistance is mainly controlled by the liquid boundary layer close to the membrane. The system was modelled and several interesting conclusions deduced. Solving the equations by means of a numerical method enabled calculation of the column height and membrane surface area required to treat a gas flow charged with of toluene.     

Current and future radionuclide speciation studies in biological media

Radionuclides may be released into the environment accidentally or incidentally, which could raise health risks when ingested or inhaled by humans. In order to study the behaviour of radionuclides in the human organism (metabolism, retention, excretion), knowledge of radionuclide speciation is indispensable: speciation governs the transfer, bioavailability and toxicity of elements and is also of considerable interest for decorporation. In this context, the Commissariat à l'Energie Atomique has created a working group on speciation to share data both on thermodynamic constants and on speciation analysis methods of interest to chemists, environmentalists and biologists. The initial focus was on the 31 radionuclides described in different International Commission on Radiological Protection models (HRTM, HAT) and the National Council on Radiation Protection model (wound). Particular attention was devoted to selecting the inorganic and organic ligands, most representative of biological media. The base applied to speciation in solution and at interfaces and solubility (BASSIST) thermodynamic database was developed for this purpose. The aim of this paper is to present the state of the art on radionuclide speciation tools within biological media and to emphasise some missing data in order to orient future research.     

Phospholipids: Identification and Implication in Muscle Pathophysiology

Phospholipids (PLs) are amphiphilic molecules that were essential for life to become cellular. PLs have not only a key role in compartmentation as they are the main components of membrane, but they are also involved in cell signaling, cell metabolism, and even cell pathophysiology. Considered for a long time to simply be structural elements of membranes, phospholipids are increasingly being viewed as sensors of their environment and regulators of many metabolic processes. After presenting their main characteristics, we expose the increasing methods of PL detection and identification that help to understand their key role in life processes. Interest and importance of PL homeostasis is growing as pathogenic variants in genes involved in PL biosynthesis and/or remodeling are linked to human diseases. We here review diseases that involve deregulation of PL homeostasis and present a predominantly muscular phenotype.     

Contribution of treated wastewater to the microbiological quality of Seine River in Paris

Urban part of Seine River serving as drinking water supply in Paris can be heavily contaminated by Cryptosporidium spp. and Giardia duodenalis. In the absence of agricultural practice in this highly urbanized area, we investigated herein the contribution of treated wastewater to the microbiological quality of this river focusing on these two parasites. Other microorganisms such as faecal bacterial indicators, enteroviruses and oocysts of Toxoplasma gondii were assessed concurrently. Raw wastewaters were heavily contaminated by Cryptosporidium and Giardia (oo)cysts, whereas concentrations of both protozoa in treated wastewater were lower. Treated wastewater, flowed into Seine River, had a parasite concentration closed to the one found along the river, in particular at the entry of a drinking water plant (DWP). Even if faecal bacteria were reliable indicators of a reduction in parasite concentrations during the wastewater treatment, they were not correlated to protozoal contamination of wastewater and river water. Oocysts of T. gondii were not found in both raw and treated wastewater, or in Seine River. Parasitic contamination was shown to be constant in the Seine River up to 40 km upstream Paris. Altogether, these results strongly suggest that treated wastewater does not contribute to the main parasitic contamination of the Seine River usually observed in this urbanized area.     

Trace Determination of Glycols by HPLC with UV and Electrospray Ionization Mass Spectrometric Detections

A high-performance liquid chromatography/mass spectrometry (HPLC/MS) method is developed for trace determination of glycols (ethylene glycol, 1,2- and 1,3-propylene glycols, and 2,3-butylene glycol) in water after derivatization with benzoyl chloride. Benzoyl esters of glycols are separated by microcolumn reversed-phase HPLC. Sensitivity and linearity of UV detection at 237 nm is compared with electrospray ionization mass spectrometric (ESI-MS) detection using selected ion monitoring. Limits of detection (LOD) and quantitation (LOQ) for UV detection are 1 and 2 mg/L, respectively. For ESI-MS detection, LOD and LOQ are in the ranges 10-25 and 20-50 μg/L, respectively. LOD obtained by ESI-MS for the determination of glycols is improved by 2-3 orders of magnitude in comparison to previously published methods. The effect of the structure of isomeric glycols on their electrospray mass spectra is discussed. The method has been applied for the determination of glycols in aqueous matrixes containing high concentrations of salts occurring in nuclear waste disposal treatment.