Tracking of spectral lines in an ARCAP time-frequency representation

International audienceARCAP time-frequency representation of narrow-band signals are madde of instantaneous characteristics (frequencies and amplitudes), without any time li,ks. In order to extract the frequency modulations (or spectral trajectoeries), we propose to re-create them on the basis of ballistic integrator models. The analytic expression of the corresponding asymptotic Kalman filter gains allows a very simple implementation of asociation procedures including trajectory birth or death. The points being associated, a Fraser filtering leads to the smoothed spectral trajectories

Tracking of spectral lines in an ARCAP time-frequency representation

International audienceARCAP time-frequency representation of narrow-band signals are madde of instantaneous characteristics (frequencies and amplitudes), without any time li,ks. In order to extract the frequency modulations (or spectral trajectoeries), we propose to re-create them on the basis of ballistic integrator models. The analytic expression of the corresponding asymptotic Kalman filter gains allows a very simple implementation of asociation procedures including trajectory birth or death. The points being associated, a Fraser filtering leads to the smoothed spectral trajectories

Extraction of Pertinent Subsets from Time-Frequency Representations for Detection and Recognition Purposes

International audienceA time-frequency representation can highlight non-stationarities in a signal. We propose to extract subsets from the Time-Frequency Representation (TFR) for classification or recognition purposes. We developed two approaches. The first one is developed for TFRs obtained from the Short Time Fourier Transform or the gliding Minimum Variance method. The extraction of compact subsets is viewed as a segmentation of the TFR, which is performed by morphological filtering and Watershed segmentation. The second approach is developed when the TFR has been obtained using parametric estimators. We consider a hybrid estimator, the ARCAP method, and use a Kalman filter trajectory tracker to extract spectral lines. The proposed methods are illustrated by examples on natural signals : dolphin whistle acoustical signals, cavitation signals and seismic signals produced by snow avalanches

Membrane vesicles: Examination of biophysical properties with atomic force microscopy

Extracellular vesicles (EVs) are not only intensively studied to increase our fundamental knowledge on their functioning, but also for diagnosis, therapeutics and drug delivery purposes. To improve the current and potential applications of EVs, a fundamental understanding of their stability, structure, and function is crucial. Such studies can be conducted at the single particle level to gain biological and physical information about the vesicles and the particle to particle variability. A suitable technique to investigate EVs under near- to physiological conditions is atomic force microscopy (AFM). Operated in liquid, it provides images of the EVs while mechanical properties of the particles can be obtained as well. Here we present our approach and the latest results in studying the structure and mechanics of these particles

Optoelectronics – Devices and Applications

Optoelectronics - Devices and Applications is the second part of an edited anthology on the multifaced areas of optoelectronics by a selected group of authors including promising novices to experts in the field. Photonics and optoelectronics are making an impact multiple times as the semiconductor revolution made on the quality of our life. In telecommunication, entertainment devices, computational techniques, clean energy harvesting, medical instrumentation, materials and device characterization and scores of other areas of R&D the science of optics and electronics get coupled by fine technology advances to make incredibly large strides. The technology of light has advanced to a stage where disciplines sans boundaries are finding it indispensable. New design concepts are fast emerging and being tested and applications developed in an unimaginable pace and speed. The wide spectrum of topics related to optoelectronics and photonics presented here is sure to make this collection of essays extremely useful to students and other stake holders in the field such as researchers and device designers

Phytoalexins: Current Progress and Future Prospects

Phytoalexins are antimicrobial substances of low molecular weight produced by plants in response to infection or stress, which form part of their active defense mechanisms. It is now clear that phytoalexins exhibit toxicity across much of the biological spectrum, prokaryotic and eukaryotic. Starting in the 1950s, research on phytoalexins has begun with biochemistry and bio-organic chemistry, resulting in the determination of their structure, their biological activity as well as mechanisms of their synthesis and their catabolism by microorganisms. Elucidation of the biosynthesis of numerous phytoalexins has also permitted the use of molecular biology tools for the exploration of the genes encoding enzymes of their synthesis pathways and their regulators. This has led to potential applications for increasing plant resistance to diseases. Phytoalexins display an enormous diversity belonging to various chemical families such as isoflavones, isoflavanones, pterocarpans, isoflavans, flavanones, coumestans, furanoacetylenes, phenylpropanoids, steroid glycoalkaloids, norsesquiterpenoids/sesquiterpenoids, coumarins, diterpenes, ent-kaurane-related diterpenoids, acidic sesquiterpenoids, 3-deoxyanthocyanidins, naphthaldehydes, indoles and stilbenes. Research papers dealing with all aspects of phytoalexins, including structure elucidation; chemical synthesis; methods for phytoalexin analysis in plant extracts or biological fluids; biosynthesis studies including modulation of phytoalexin synthesis; engineering of phytoalexin biochemical pathways in plants and microbes; biological activities; structure/activity relationships; phytoalexin metabolism in planta and by micro-organisms; roles and ATP Binding Cassette (ABC) transporters or Multi-Drugs Efflux (MDE) transporters are welcome for inclusion in this Special Issue of Molecules. Review articles, particularly those dealing with the themes mentioned above are also particularly welcome for inclusion

Spacecraft Environmental Interactions Technology, 1983

State of the art of environment interactions dealing with low-Earth-orbit plasmas; high-voltage systems; spacecraft charging; materials effects; and direction of future programs are contained in over 50 papers

Massachusetts Domestic and Foreign Corporations Subject to an Excise: For the Use of Assessors (2004)

International audienc