Thales (Germany)

Protein-protein interacting surfaces are usually large and intricate, making the rational design of small mimetics of these interfaces a daunting problem. On the basis of a structural similarity between the CDR2-like loop of CD4 and the beta-hairpin region of a short scorpion toxin, scyllatoxin, we transferred the side chains of nine residues of CD4, central in the binding to HIV-1 envelope glycoprotein (gp120), to a structurally homologous region of the scorpion toxin scaffold. In competition experiments, the resulting 27-amino acid miniprotein inhibited binding of CD4 to gp120 with a 40 microM IC(50). Structural analysis by NMR showed that both the backbone of the chimeric beta-hairpin and the introduced side chains adopted conformations similar to those of the parent CD4. Systematic single mutations suggested that most CD4 residues from the CDR2-like loop were reproduced in the miniprotein, including the critical Phe-43. The structural and functional analysis performed suggested five additional mutations that, once incorporated in the miniprotein, increased its affinity for gp120 by 100-fold to an IC(50) of 0.1-1.0 microM, depending on viral strains. The resulting mini-CD4 inhibited infection of CD4(+) cells by different virus isolates. Thus, core regions of large protein-protein interfaces can be reproduced in miniprotein scaffolds, offering possibilities for the development of inhibitors of protein-protein interactions that may represent useful tools in biology and in drug discovery.

This letter presents a new phase-shifting cell for linearly polarized reflectarray applications. It provides a nearly 360° phase range and naturally comes back to its initial geometry after the phase cycle has been achieved. A complete analysis of the resonating mechanism is given, and a low dispersion (<;30°/GHz) is demonstrated over a large bandwidth (18%) in simulation.

A broadband planar Sierpinski fractal antenna for multiband application is proposed, designed, and tested. The perturbed Sierpinski fractal patch and slotted ground plane are employed to achieve broadband characteristics. The implemented antenna including the ground plane has a total dimension of 100 times 53.7 times 0.8 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . The measured 10-dB return loss bandwidths are 808-1008 MHz (22%) and 1581-2760 MHz (54.3%), which cover the GSM/DCS/PCS/IMT-2000/ISM/satellite DMB bands. The measured return loss, radiation patterns, and gain of the proposed antenna are presented and compared with simulated results.

Context. The first Gaia Data Release contains the Tycho - Gaia Astrometric Solution (TGAS). This is a subset of about 2 million stars for which, besides the position and photometry, the proper motion and parallax are calculated using H ipparcos and Tycho-2 positions in 1991.25 as prior information. Aims. We investigate the scientific potential and limitations of the TGAS component by means of the astrometric data for open clusters. Methods. Mean cluster parallax and proper motion values are derived taking into account the error correlations within the astrometric solutions for individual stars, an estimate of the internal velocity dispersion in the cluster, and, where relevant, the effects of the depth of the cluster along the line of sight. Internal consistency of the TGAS data is assessed. Results. Values given for standard uncertainties are still inaccurate and may lead to unrealistic unit-weight standard deviations of least squares solutions for cluster parameters. Reconstructed mean cluster parallax and proper motion values are generally in very good agreement with earlier H ipparcos -based determination, although the Gaia mean parallax for the Pleiades is a significant exception. We have no current explanation for that discrepancy. Most clusters are observed to extend to nearly 15 pc from the cluster centre, and it will be up to future Gaia releases to establish whether those potential cluster-member stars are still dynamically bound to the clusters. Conclusions. The Gaia DR1 provides the means to examine open clusters far beyond their more easily visible cores, and can provide membership assessments based on proper motions and parallaxes. A combined HR diagram shows the same features as observed before using the H ipparcos data, with clearly increased luminosities for older A and F dwarfs.

We demonstrate for the first time a radiation-resistant Erbium-Doped Fiber exhibiting performances that can fill the requirements of Erbium-Doped Fiber Amplifiers for space applications. This is based on an Aluminum co-doping atom reduction enabled by Nanoparticules Doping-Process. For this purpose, we developed several fibers containing very different erbium and aluminum concentrations, and tested them in the same optical amplifier configuration. This work allows to bring to the fore a highly radiation resistant Erbium-doped pure silica optical fiber exhibiting a low quenching level. This result is an important step as the EDFA is increasingly recognized as an enabling technology for the extensive use of photonic sub-systems in future satellites.

In September 2015, the ADAPT Centre for Digital Content Technology carried out a focus group study of 70 translators at the European Commission’s Directorate-General for Translation (DGT). The aim was to better understand the factors involved in the translators’ adoption and non-adoption of machine translation (MT) during their translation tasks. Our analysis showed that, while broadly positive attitudes to MT could be observed, MT was not consistently adopted for all tasks. We argue that ergonomic factors related to a human translator’s needs, abilities, limitations, and overall well-being heavily impacted on participants’ decisions to use MT or not in their tasks. We further claim that it is only by taking into account the special institutional circumstances in which the activity of DGT translation is situated that these ergonomic factors can be fully understood and explained.

Machine-Type Communications are meeting a growing interest on the consumer market. Dedicated technologies arise to support more robust communications involving a massive number of low cost, low energy-consuming devices. This paper discusses the coverage extension of a Low-Powered Wide Area Network using a Low Earth Orbit satellite constellation, benefiting from the improved performance of a recent standard. The transmission complies with the user equipment specifications standardized as NB-IoT by 3GPP in Release 13. This radio technology is an update on LTE standard with enhanced performances: the supported path loss can be 20 dB higher than with legacy LTE. This improvement makes satellite- compatible the small and energy-constrained devices. A specific unidirectional system is defined, and a link budget is derived. Also, a receiver architecture is presented, that takes into consideration satellite channel specific impairments.

This article deals with X-band radar trial campaigns in 2006 and 2007 at Orly Airport, and in June 2008 at Paris-CDG Airport. An X-band Doppler radar has been deployed to assess short range (inferior to 2000 m) wake vortex monitoring capabilities in all weather conditions (dry and wet conditions). Recorded data have been correlated with electromagnetic and fluid mechanical models of wake turbulences for better and more accurate understanding of roll-up radar cross section (RCS) and Doppler signature.

An analytical model based on geometrical optics is proposed to design and analyze continuous parallel plate waveguide (PPW) lens-like antennas. The proposed design is based on a transversal PPW section working as a lens-like beamformer. By simplifying the propagation inside this transversal section, a bifocal constrained lens model is first defined; it provides a relevant starting point to design the proposed beamformer. A refined model based on ray tracing and with an enhanced performance prediction is achieved by accounting the wave propagation inside the transversal cavity. The numerical analysis of phase aberrations and radiation demonstrate the performance of the proposed beamformer. The results of the ray-tracing model are in a very good agreement with the corresponding full-wave model, while providing a significant reduction in the computational effort, making the proposed model more suitable for advanced optimization processes.

A novel all-metal graded index Gutman lens is proposed. It exploits an interleaved metasurface unit-cell with glide symmetry that can provide high values of equivalent refractive index with low frequency dispersion. The result is a compact lens with broadband performance and a wide field of view up to ±70 ° . The proposed lens exhibits low loss, directive beams and is an appealing candidate for space applications. The design approach introduced can be applied to other graded index lenses with circular symmetry using rectangular or circular periodic structures.

In this paper, we propose a novel timing estimation method for orthogonal frequency division multiplexing (OFDM) systems. The most common approaches in estimating timing use correlation by using a given preamble. Thus, the estimation performance is directly dependent on the specific preamble type. The proposed algorithm estimates the timing by using a simple circular shift operation of the given preamble at the receiver. For this reason, the proposed method can be used for any of the OFDM systems regardless of their preamble structures. The simulation results investigated in this paper reveal that the proposed method remarkably increases the estimation performance by more than 5 dB in terms of the mean squared error compared to conventional methods. We also consider the computational complexity of the methods and introduce a simple structure to reduce the computational burden of the proposed method.

An integrated 1024/spl times/1024 CMOS image sensor with programmable region-of-interest (ROI) readout and multiexposure technique has been developed and successfully tested. Size and position of the ROI is programmed based on multiples of a minimum readout kernel of 32/spl times/32 pixels. Since the dynamic range of the irradiance normally exceeds the electrical dynamic range of the imager that can be covered using a single integration time, a multiexposure technique has been implemented in the imager. Subsequent sensor images are acquired using different integration times and recomputed to form a single composite image. A newly developed algorithm performing the recomputation is presented. The chip has been realized in a 0.5-/spl mu/m n-well standard CMOS process. The pixel pitch is 10 /spl mu/m/sup 2/ and the total chip area is 164 mm/sup 2/.

Abstract In this article, we present a concrete realisation of the ETCS hybrid level 3 concept, whose practical viability was evaluated in a field demonstration in 2017. Hybrid level 3 introduces virtual subsections as sub-divisions of classical track sections with trackside train detection. Our approach introduces an add-on for the radio block centre (RBC) of Thales, called virtual block function (VBF), which computes the occupation states of the virtual subsections using the train position reports, train integrity information, and the track occupation states. From the perspective of the RBC, the VBF behaves as an interlocking that transmits all signal aspects for virtual signals introduced for each virtual subsection to the RBC. We report on the development of the VBF, implemented as a formal B model executed at runtime using ProB and successfully used in a field demonstration to control real trains.

The properties of high-frequency (HF) instabilities (f > MHz) in Hall thrusters are reviewed on the basis of a large experimental data set previously obtained with the use of antennas, probes, and magnetic coils. The phenomenological representations of their physical sources are discussed. The development of these HF instabilities results in anomalous electron transport, and the corresponding transport coefficients are evaluated from these experimental data.

Commercial Ku-band tapered helix traveling-wave tubes (TWTs) and a folded-waveguide Q -band TWT are modeled and simulated in CST Particle Studio (PS) on a desktop computer. Efficient models for the electron beam, the severs, and the delay line are investigated to enable accurate and automatable model generation, simulation, as well as pre- and postprocessing. The results of particle-in-cell simulation in CST PS are presented and compared to those of the specialized steady-state simulation codes MVTRAD and KlysTOP, as well as to measurements.

The particle-in-cell (PIC) method is used to study two different ion thruster concepts-stationary plasma thrusters (SPTs) and high-efficiency multistage plasma thrusters (HEMP-Ts)-in particular, the plasma properties in the discharge chamber due to the different magnetic field configurations. Special attention is paid to the simulation of plasma particle fluxes on the thrusters' channel surfaces. In both cases, PIC proves itself as a powerful tool, delivering important insight into the basic physics of the different thruster concepts. The simulations demonstrated that the new HEMP-T concept allows for a high thermal efficiency due to both minimal energy dissipation and high acceleration efficiency. In the HEMP-T, the plasma contact to the wall is limited only to very small areas of the magnetic field cusps, which results in small ion energy flux to the thruster channel surface. The erosion yields for dielectric discharge channel walls of SPT and HEMP-Ts were calculated with the binary collision code SDTrimSP. For HEMP, thruster simulations have shown that there is no erosion inside the dielectric discharge channel.

In this tutorial, the Ghidra software reverse engineering framework will be presented, its characteristics highlighted and its features to the hitherto industry standard in reverse engineering tools, IDA Pro - the interactive disassembler, compared against. This framework was released on March the 5th 2019, by the National Security Agency under the Apache v2 license and brought with it a powerful decompiler for many different architectures (X86 16/32/64, ARM/AARCH64, Java/DEX bytecode, ...), which will be presented and its underlying intermediate language p-code and the corresponding SLEIGH-format explained. Further, hands-on demonstrations will follow, including the aforementioned SLEIGH-format, the plugin-system and the standalone-mode, showcased on different reverse engineering tasks like binary diffing, code lifting, deobfuscation and patching.

Analog Transient Radiation Effects in Electronics (ATREE) induced by high dose-rate X-ray pulses are investigated using a flash X-ray facility. The ATREEs induced in a LM124 operational amplifier configured in three different bias configurations are investigated. A predictive methodology, based upon a previously developed ASET simulation tool, is used to model the ATREE phenomena. A semiempirical physical model is used to perform the correlation between the duration of the parasitic pulse signal induced in the LM124 and an equivalent value of the high dose-rate X-ray pulse level.

In this paper, we design and evaluate an Autonomous Cyber Defence (ACD) agent to monitor and act within critical network segments connected to untrusted infrastructure hosting active adversaries. We assume that modern network segments use software-defined controllers with the means to host ACD agents and other cybersecurity tools that implement hybrid AI models. Our agent uses a hybrid AI architecture that integrates deep reinforcement learning (DRL), augmented Large Language Models (LLMs), and rule-based systems. This architecture can be implemented in software-defined network controllers , enabling automated defensive actions such as monitoring, analysis, decoy deployment, service removal, and recovery. A core contribution of our work is the construction of three cybersecurity knowledge graphs that organise and map data from network logs, open source Cyber Threat Intelligence (CTI) reports, and vulnerability frameworks. These graphs enable automatic mapping of Common Vulnerabilities and Exposures (CVEs) to offensive tactics and techniques defined in the MITRE ATT&CK framework using Bidirectional Encoder Representations from Transformers (BERT) and Generative Pre-trained Transformer (GPT) models. Our experimental evaluation of the knowledge graphs shows that BERT-based models perform better, with precision (83.02%), recall (75.92%), and macro F1 scores (58.70%) significantly outperforming GPT models. The ACD agent was evaluated in a Cyber Operations Research (ACO) gym against eleven DRL models, including Proximal Policy Optimisation (PPO), Hierarchical PPO, and ensembles under two different attacker strategies. The results show that our ACD agent outperformed baseline implementations , with its DRL models effectively mitigating attacks and recovering compromised systems. In addition, we implemented and evaluated a chatbot using Retrieval-Augmented Generation (RAG) and a prompting agent augmented with the CTI reports represented in the cybersecurity knowledge graphs. The chatbot achieved high scores on generation metrics such as relevance (0.85), faithfulness (0.83), and semantic similarity (0.88), as well as retrieval metrics such as contextual precision (0.91). The experimental results suggest that the integration of hybrid AI systems with knowledge graphs can enable the automation and improve the precision of cyber defence operations, and also provide a robust interface for cybersecurity experts to interpret and respond to advanced cybersecurity threats.

Certain GNSS applications conceived for road users in urban scenarios must meet some particular integrity requirements to assure the system safety, reliability or credibility. For instance, GNSS-based Road User Charging is one of these applications that recently has attracted special interest. A correct design of such applications needs the knowledge of the GNSS error distribution. Furthermore, the GNSS error model should have been built with overbounding techniques. The user is a vehicle equipped with a GNSS receiver that may track different signals of various systems (GPS, Galileo, SBAS), in a single- or dual-frequency configuration. The different error sources contributing to the total pseudorange error are identified, analyzed and modeled, using overbounding techniques when necessary. Finally the pseudorange measurement error model is obtained and analyzed for different receiver configurations.