Satimo (France)

Abstract The seawater partial pressure of carbon dioxide (pCO2) is an essential ocean variable needed to calculate air‐sea gas exchange and to identify marine carbon sinks and sources. Recent technological developments support autonomous pCO2 measurements with sensors that are smaller and cheaper. In July 2021, these differences were highlighted during the Integrated Carbon Observation System—Ocean Thematic Centre laboratory intercomparison exercise. A key message from the intercomparison was the need for further field comparisons. Here we present the results from a field test of two generations of ‐4H‐Jena HydroC CO2‐FT membrane‐based sensors alongside a General Oceanics equilibrator system. The intercomparisons were done onboard a ship‐of‐opportunity regularly traveling between Europe and South America. The first phase of the experiment took place in 2021, when the difference between the two instruments was within ± 10 μatm during 53% of the intercomparison time. For the second phase, improvements were made, including the addition of an automated cleaning routine for the membrane‐based sensor, the installation of a new sensor prototype with the ability to measure a reference gas, and an updated data processing method. These changes improved the performance and, during the last 2023 journey, the mean difference decreased to 2.0 ± 5.0 μatm, and was within ± 10 μatm during 97% of the deployment time. This experiment revealed that with a suitable deployment approach considering biofouling and reference gas measurements, membrane‐based sensors can measure seawater pCO2 within the Global Ocean Acidification Observing Network weather goal of 2.5% relative uncertainty on autonomous installations.

Decompression sickness can occur in divers even when recommended decompression procedures are followed. Furthermore, the physiological state of individuals can significantly affect bubbling variability. These informations highlight the need for personalized input to improve decompression in SCUBA diving. The main objective of this study is to propose a fundamental framework for a new approach to inert gas exchanges. A physiological model of oxygen delivery to organs and tissues has been built and adapted to nitrogen. The validation of the model was made by transferring the N2 to CO2. Under normobaric conditions (air breathing, oxygen breathing, and static apnea) and hyperbaric conditions, the O2 model replicates the reference physiological Po2 (Spearman correlation tests P < 0.001). The inert gas models can simulate inert gas partial pressures under normobaric and hyperbaric conditions. However, the lack of reference values prevents direct validation of this new model. Therefore, the N2 model has been transferred to CO2. The resulting CO2 model has been validated by comparing it with physiological reference values (Spearman correlation tests P < 0.01). The validity of the CO2 model constructed from the N2 model demonstrates the plausibility of this physiological model of inert gas exchanges. In the context of personalized decompression procedures, the proposed model is of significant interest as it enables the integration of physiological and morphological parameters (blood and respiratory flows, alveolo-capillary diffusion, respiratory and blood volumes, oxygen consumption rate, fat mass, etc.) into a model of nitrogen saturation/desaturation, in which oxygen and CO2 partial pressures can also be incorporated.NEW & NOTEWORTHY This is the first model of inert gas transport based on the physiology of respiratory gas. It was built for O2 delivery and validated against literature data; it was then transposed to N2 exchanges. The transposition procedure was checked by transposing the N2 model to CO2 (and validated against literature data). This model opens the possibility to integrate physiological and morphological inputs in a personalized decompression procedure in SCUBA diving.

This paper proposes a parametric-based network architecture for joint channel estimation and data detection in communications systems with hardware impairments. This architecture is composed of a data-augmented layer, a custom soft thresholding function, and several linear layers modeling the effect of channel effects and hardware impairments. In the proposed network, the soft thresholding function softly constrains the detected data to be within the considered constellation. The latter depends only on one one parameter that is optimized during training. The benefit of the proposed approach is illustrated through a communication chain corrupted by multiple impairments and noises.

Describes experimental work performed within the Mesoscale Ocean Radar Signature Experiments (MORSE) project as part of the EC MAST-III programme. The aim of these experiments is to further the understanding of the imaging of internal waves by satellite SAR. Of particular interest to the project is the dependency of the imaging process on the radar wavelength in the millimetre range. Hence a laboratory mm-wave FMCW SAR (91 GHz) has been developed at University College London. Then, two sets of experiments have been carried out above the linear flume and in the Coriolis circular wave-tank of Laboratoire des Ecoulements Ge/spl acute/ophysiques et Industriels in Grenoble, in order to image surface wave fields in the presence of an internal wave.

Integration of image sequences, text records and still images, seems to be the next step towards a functional Gastroenterology Patient Record (GPR), This paper discusses the motivation of such approach, describes a multimedia GPR data model, how it functions and the challenges it faces.

This chapter analyses the theoretical multiple-input multiple-output (MIMO) channel capacity based on an extensive measurement set of MIMO power line communication (PLC) channels obtained during the European Telecommunications Standards Institute (ETSI) measurement campaign of Specialist Task Force (STF) 410. MIMO systems have been used for many years in the field of wireless communications. The huge increase in coverage and capacity offered by MIMO technology are the key benefits of using multiple sensors at the transmitter (Tx) and receiver (Rx). The MIMO PLC channel capacity was investigated for the first time based on in-home PLC measurements in German houses and flats. These investigations were further elaborated by Schneider in 2012. The statistical analysis of the channel capacity is based on the MIMO PLC channels obtained in the European (EU) field measurement campaign of ETSI STF410. This measurement campaign recorded the complex S21 scattering parameter hundreds of outlets for different MIMO feeding and receiving options.

Somewhat Homomorphic Encryption (SHE) schemes allow to carry out operations on data in the cipher domain. In a cloud computing scenario, personal information can be processed secretly, inferring a high level of confidentiality. Most practical Somewhat Homomorphic Encryption (SHE) schemes require the implementation of fast polynomial arithmetic, that is why hardware accelerators usually target the FFT/NTT algorithm. This paper proposes a co-design hardware/software approach to accelerate SHE using Karatsuba algorithm. Depending on the needs, Karatsuba algorithm allows to implement additional computations to the hardware in order to reduce software computation time. Our accelerator is designed to speed up arithmetic on degree 2560 polynomials with 125 bits coefficients. We provide 3 different approaches: An area efficient design, a balanced design, and a performance-oriented design. Our accelerator performs a polynomial multiplication in respectively 2.46 ms, 1.70 ms and 1.24 ms, and a relinearization operation in 2.28 ms, 1.53 ms and 1.1 ms, while a functionally equivalent design using the FFT [1] performs the multiplication in 1.96 ms and the relinearization in 4.79 ms for hardware resources consumption equivalent to the balanced design.

Complex media have gained interest in microwave and millimeter-wave devices. They display some interesting characteristics such as, for instance, tunability and controlled filtering capacity. However, such media are generally very complex as they can be fully nonhomogeneous; frequency dependent, anisotropic, time dependent, or chiral. This requires simulation techniques capable of solving Maxwell’s equations accounting for such media. Also, apart comparison with rather difficult measurement, canonical solutions are not available for validation. In this paper, the concept of transformation optics (TO) is presented as a systematic tool to construct computational problems involving complex media for which the analytical solution is known. Several examples are shown for validation of a new transmission-line matrix (TLM) cell that model complex media.