Team cognition in a cyber defense context: focus on social support behaviors

In the face of increasingly prominent cyber security issues, the organization of cyber team analysts has become crucial to thwart cyber threats. Few studies have examined the functioning of the team and the interaction between individuals in a cyber defense context and how the context influences team adaptation. The present study investigates team cognition in a cyber defense context and in particular the nature of task- or team-centered communication among analysts during a cyber defense simulation exercise. Results indicate that markers of situation assessment and shared mental models are both strategically present and linked. Nevertheless, the frequency of these markers varies depending on the quantity and quality of problems encountered; in particular, variations in social support behaviors are observed. Decreasing social support behaviors during high level activities suggests the adaptation of social behaviors depending on the threats and attacks on the system. Theoretical and practical implications are discussed in terms of theories and potential consequences for strategic adaptation and team resilience.

     

Coherent microscopy by laser optical feedback imaging (LOFI) technique

The application of the non-conventional imaging technique LOFI (laser optical feedback imaging) to coherent microscopy is presented. This simple and efficient technique using frequency-shifted optical feedback needs the sample to be scanned in order to obtain an image. The effects on magnitude and phase signals such as vignetting and field curvature occasioned by the scanning with galvanometric mirrors are discussed. A simple monitoring method based on phase images is proposed to find the optimal position of the scanner. Finally, some experimental results illustrating this technique are presented.     

Passive but not active CD8+ T cell-based immunotherapy interferes with liver tumor progression in a transgenic mouse model

To evaluate tumor immunotherapies, we used transgenic mice that harbor a progressive liver tumor associated with the expression of the SV40 large tumor T oncoprotein (SV40-T). To induce "self" tumor Ag-specific CD8+ T cells, mice were injected with an immunodominant SV40-T CTL epitope mixed with a heterologous helper peptide. Despite repeated injections, this vaccine failed to raise a tumor-specific CD8+ T cell response that was efficient enough to counteract tumors. Although coimmunization with SV40-T CTL epitope and heterologous helper peptide efficiently recruited the respective Th cells, only low-avidity SV40-T-specific CD8+ T cells were activated. Furthermore, major alterations in SV40-T-specific B and Th cell responses were characterized. In contrast, transfers of higher-avidity CTLs specific for the same SV40-T epitope were effective in counteracting tumors. These results suggest that passive therapies targeted to self tumor Ag may be more suitable than active immunization in the treatment of spontaneous tumors.     

Model-based diagnosis of large diesel engines based on angular speed variations of the crankshaft

This work aims at monitoring large diesel engines by analyzing the crankshaft angular speed variations. It focuses on a powerful 20-cylinder diesel engine with crankshaft natural frequencies within the operating speed range. First, the angular speed variations are modeled at the crankshaft free end. This includes modeling both the crankshaft dynamical behavior and the excitation torques. As the engine is very large, the first crankshaft torsional modes are in the low frequency range. A model with the assumption of a flexible crankshaft is required. The excitation torques depend on the in-cylinder pressure curve. The latter is modeled with a phenomenological model. Mechanical and combustion parameters of the model are optimized with the help of actual data. Then, an automated diagnosis based on an artificially intelligent system is proposed. Neural networks are used for pattern recognition of the angular speed waveforms in normal and faulty conditions. Reference patterns required in the training phase are computed with the model, calibrated using a small number of actual measurements. Promising results are obtained. An experimental fuel leakage fault is successfully diagnosed, including detection and localization of the faulty cylinder, as well as the approximation of the fault severity.     

Studies of the antenna effect in polymer molecules. 29. Synthesis and properties of poly[sodium styrene sulfonate-co-(4-acryolyloxyphenyl)-10,15,20-tritolylporphyrin] in aqueous solution

The novel water soluble antenna polyelectrolyte: poly[sodium styrene sulfonate-co-(4-acryolyloxyphenyl)-10,15,20-tritolylporphyrin] (PSSS-Po) was synthesised, and its photophysical and photochemical properties were studied. Solubilisation of the various molecular probes such as pyrene or perylene in aqueous solution of the PSSS-Po proved that the polymer chain adopts the compact conformation. The interior of the polymer pseudomicelle is significantly less polar than water. The effective quenching of polymeric porphyrin fluorescence by sulfopropyl viologen (SPV) can be explained considering the possibility of electron transfer from the singlet-excited state of Po to SPV. This has been supported by measuring an absorption spectrum for PSSS-Po/SPV system after selective irradiation of Po chromophores. The formation of the new absorption bands characteristic for SPV⁻ radical anion indicated that the charge separation was achieved in that system.     

Molecular probe studies of crystallinity in polyethylene

The molecular probe technique uses a standard gas chromatograph modified to obtain a printed digital record of retention time vs. column temperature to be obtained automatically. From this the observed specific retention time, V_g, can be calculated. If V_g is the theoretical value it can be deduced that: % Crystallinity = [1 ? V_g/V_g′ ] × 100. Experimental results using Tenite 800 and Tenite 3310 polyethylene produced and sold by Eastman Chemical Products Inc., Kingsport, Tennessee, U.S.A. justify this equation.     

Metallo‐Supramolecular Block Copolymers

Supramolecular copolymers have become of increasing interest in recent years for the search of new materials with tunable properties. In particular, metallo‐supramolecular block copolymers—copolymers in which the blocks are linked together by a metal–ligand complex—have seen important progresses, allowing better control over the synthetic strategies for various architectures, and providing a better understanding of the parameters governing their self‐assembly. We review here recent developments on the synthesis and self‐assembly of such materials achieved in this field.     

Influence of very long aging on the relaxation behavior of flame‐retardant printed circuit board epoxy composites under mechatronic conditions

Very long aging times, up to 15,100 h (629 days) at 110°C, were achieved on flame‐retardant printed circuit board laminates commonly used in automotive design. This composite was fabricated from glass fibers embedded in an epoxy resin. Aging was performed in an oven under an air atmosphere at a temperature lower than the glass‐transition temperature. Temperature‐modulated differential scanning calorimetric analysis was used to investigate the influence of such aging on the glass‐transition phenomena. A new amorphous phase appeared during aging. By extending the analysis to samples collected at different thicknesses, we demonstrated the existence of a time‐dependent gradient of the properties. A skin–core structure was evidenced, and this slowed down oxidation and allowed physical aging to occur in the bulk sample. An exponential law described the variations of the glass‐transition of the new external compound. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 786‐792, 2013     

Gold nanoparticle assemblies: Thermal behaviour under optical excitation

The optical response of materials based on gold nanoparticle assemblies depends on many parameters connected to both material morphology and light excitation characteristics. The optical energy absorbed is then converted into heat through different nanoscale energy exchange mechanisms. This heating subsequently modifies itself the optical properties. We investigate the interplay between the optical and thermal responses of nanocomposite media under its theoretical aspect. In this first paper, the thermal response of gold nanoparticle assemblies under pulsed optical excitation is considered. Both conventional and original modelling approaches are presented. We first underline the role of electromagnetic interactions between particles in a dense assembly in its linear optical response. We then show how the interaction of light with matrix-embedded gold nanoparticles can result in the generation of thermal excitations through different energy exchange mechanisms. Finally, we demonstrate the possible significant influence of the heat carrier ballistic regime and phonon rarefaction in the cooling dynamics of an embedded gold nanoparticle subsequent to ultrafast pulsed laser excitation.