scholarly journals Cloud information content analysis of multi-angular measurements in the oxygen A-band: application to 3MI and MSPI

2016 ◽  
Vol 9 (10) ◽  
pp. 4977-4995 ◽  
Author(s):  
Guillaume Merlin ◽  
Jérôme Riedi ◽  
Laurent C. Labonnote ◽  
Céline Cornet ◽  
Anthony B. Davis ◽  
...  
Keyword(s):  
Information Content ◽  
Surface Albedo ◽  
Signal To Noise Ratio ◽  
Quantitative Information ◽  
High Accuracy ◽  
Polarization Imaging ◽  
Angular Measurements ◽  
Black Surface ◽  
Imaging Instrument ◽  
Almost All

Abstract. Information content analyses on cloud top altitude (CTOP) and geometrical thickness (CGT) from multi-angular A-band measurements in the case of monolayer homogeneous clouds are conducted. In the framework of future multi-angular radiometer development, we compared the potential performances of the 3MI (Multi-viewing, Multi-channel and Multi-polarization Imaging) instrument developed by EUMETSAT, which is an extension of POLDER/PARASOL instrument and MSPI (Multiangle SpectroPolarimetric Imager) developed by NASA's Jet Propulsion Laboratory. Quantitative information content estimates were realized for thin, moderately opaque and opaque clouds for different surface albedo and viewing geometry configurations. Analyses show that retrieval of CTOP is possible with a high accuracy in most of the cases investigated. Retrieval of CGT is also possible for optically thick clouds above a black surface, at least when CGT > 1–2 km and for thin clouds for CGT > 2–3 km. However, for intermediate optical thicknesses (COT ≃ 4), we show that the retrieval of CGT is not simultaneously possible with CTOP. A comparison between 3MI and MSPI shows a higher information content for MSPI's measurements, traceable to a thinner filter inside the oxygen A-band, yielding higher signal-to-noise ratio for absorption estimation. Cases of cloud scenes above bright surfaces are more complex but it is shown that the retrieval of CTOP remains possible in almost all situations while the information content on CGT appears to be insufficient in many cases, particularly for COT < 4 and CGT < 2–3 km.

scholarly journals Cloud information content analysis of multi-angular measurements in the oxygen A-band: application to 3MI and MSPI

2015 ◽  
Vol 8 (12) ◽  
pp. 12709-12758
Author(s):  
G. Merlin ◽  
J. Riedi ◽  
L. C. Labonnote ◽  
C. Cornet ◽  
A. B. Davis ◽  
...  
Keyword(s):  
Content Analysis ◽  
Information Content ◽  
Polarized Light ◽  
Quantitative Information ◽  
Ice Cloud ◽  
Cloud Properties ◽  
Spectral Bands ◽  
Angular Measurements ◽  
Black Surface ◽  
Almost All

Abstract. The vertical distribution of cloud cover has a significant impact on a large number of meteorological and climatic processes. Cloud top altitude and cloud geometrical thickness are then essential. Previous studies established the possibility of retrieving those parameters from multi-angular oxygen A-band measurements. Here we perform a study and comparison of the performances of future instruments. The 3MI (Multi-angle, Multi-channel and Multi-polarization Imager) instrument developed by EUMETSAT, which is an extension of the POLDER/PARASOL instrument, and MSPI (Multi-angles Spectro-Polarimetric Imager) develoloped by NASA's Jet Propulsion Laboratory will measure total and polarized light reflected by the Earth's atmosphere–surface system in several spectral bands (from UV to SWIR) and several viewing geometries. Those instruments should provide opportunities to observe the links between the cloud structures and the anisotropy of the reflected solar radiation into space. Specific algorithms will need be developed in order to take advantage of the new capabilities of this instrument. However, prior to this effort, we need to understand, through a theoretical Shannon information content analysis, the limits and advantages of these new instruments for retrieving liquid and ice cloud properties, and especially, in this study, the amount of information coming from the A-Band channel on the cloud top altitude (CTOP) and geometrical thickness (CGT). We compare the information content of 3MI A-Band in two configurations and that of MSPI. Quantitative information content estimates show that the retrieval of CTOP with a high accuracy is possible in almost all cases investigated. The retrieval of CGT seems less easy but possible for optically thick clouds above a black surface, at least when CGT > 1–2 km.

Advertisements for Medicines in Leading Medical Journals in 18 Countries: A 12-Month Survey of Information Content and Standards

1993 ◽  
Vol 23 (1) ◽  
pp. 161-172 ◽  
Author(s):  
Andrew Herxheimer ◽  
Cecilia Stålsby Lundborg ◽  
Barbro Westerholm
Keyword(s):  
Information Content ◽  
Medical Information ◽  
Industrialized Countries ◽  
Brand Name ◽  
Negative Effects ◽  
Medical Journals ◽  
National Medical ◽  
Ethical Criteria ◽  
Almost All ◽  
Medicinal Drug

The information content of 6,710 advertisements for medicines in medical journals was surveyed to provide a baseline for monitoring the effect of WHO's Ethical Criteria for Medicinal Drug Promotion. The advertisements (ads) appeared during 12 months (1987–1988) in 23 leading national medical journals in 18 countries. Local participants, mostly doctors or pharmacists, examined them. The presence or absence in each ad of important information was noted. In most ads the generic name appeared in smaller type than the brand name. Indications were mentioned more often than the negative effects of medicines. The ads gave less pharmacological than medical information. However, important warnings and precautions were missing in half, and side effects and contraindications in about 40 percent. Prices tended to be given only in countries where a social security system pays for the medicines. The information content of ads in the developing countries differed surprisingly little from that in the industrialized countries. Almost all the ads (96 percent) included one or more pictures; 58 percent of these were considered irrelevant. The authors believe it is a mistake to regard ads as trivial. If they are not considered seriously they will influence the use of medicines as they are intended to do, but read critically they can provide useful information.

scholarly journals MULTI-CHANNEL FRY COUNTER DESIGN USING OPTOCOUPLER SENSOR

2019 ◽  
Vol 4 (2) ◽  
pp. 97-104
Author(s):  
Lazuardi Umar ◽  
Yanuar Hamzah ◽  
Rahmondia N. Setiadi
Keyword(s):  
Counting Process ◽  
Production Capacity ◽  
High Accuracy ◽  
Limited Capacity ◽  
High Concentration ◽  
Counting System ◽  
Channel Detection ◽  
Accuracy Level ◽  
High Level ◽  
Almost All

This paper describes a design of a fry counter intended to be used by consuming fish farmer. Along this time, almost all the fry counting process is counted by manual, which is done by a human. It is requiring much energy and needs high concentration; thus, can cause a high level of exhaustion for the fry counting worker. Besides that, the human capability and capacity of counting are limited to a low level. A fry counter design in this study utilizes a multi-channel optocoupler sensor to increase the counting capacity. The multi-channel fry counter counting system is developed as a solution to a limited capacity of available fry counter. This design uses an input signal extender system on controller including the interrupt system. From the experiment, high accuracy level is obtained on the counting and channel detection, therefore, this design can be implemented and could help farmers to increase the production capacity of consuming fish.

Role of GABAergic Inhibition in the Coding of Interaural Time Differences of Low-Frequency Sounds in the Inferior Colliculus

2005 ◽  
Vol 93 (6) ◽  
pp. 3390-3400 ◽  
Author(s):  
W. R. D’Angelo ◽  
S. J. Sterbing ◽  
E.-M. Ostapoff ◽  
S. Kuwada
Keyword(s):  
Inferior Colliculus ◽  
Signal To Noise Ratio ◽  
Interaural Time Difference ◽  
Low Frequency ◽  
Gabaergic Inhibition ◽  
Interaural Time Differences ◽  
Gaba Antagonists ◽  
Inhibitory Transmitter ◽  
Almost All

A major cue for the localization of sound in space is the interaural time difference (ITD). We examined the role of inhibition in the shaping of ITD responses in the inferior colliculus (IC) by iontophoretically ejecting γ-aminobutyric acid (GABA) antagonists and GABA itself using a multibarrel pipette. The GABA antagonists block inhibition, whereas the applied GABA provides a constant level of inhibition. The effects on ITD responses were evaluated before, during and after the application of the drugs. If GABA-mediated inhibition is involved in shaping ITD tuning in IC neurons, then applying additional amounts of this inhibitory transmitter should alter ITD tuning. Indeed, for almost all neurons tested, applying GABA reduced the firing rate and consequently sharpened ITD tuning. Conversely, blocking GABA-mediated inhibition increased the activity of IC neurons, often reduced the signal-to-noise ratio and often broadened ITD tuning. Blocking GABA could also alter the shape of the ITD function and shift its peak suggesting that the role of inhibition is multifaceted. These effects indicate that GABAergic inhibition at the level of the IC is important for ITD coding.

Serotonergic Modulation of Spontaneous and Evoked Transmitter Release in Layer II Pyramidal Cells of Rat Somatosensory Cortex

2020 ◽  
Author(s):  
Fransiscus Adrian Agahari ◽  
Christian Stricker
Keyword(s):  
Somatosensory Cortex ◽  
Transmitter Release ◽  
Barrel Cortex ◽  
Signal To Noise Ratio ◽  
Pyramidal Cells ◽  
Mepsc Frequency ◽  
Spontaneous Noise ◽  
Synaptic Dynamics ◽  
Rat Somatosensory Cortex ◽  
Almost All

Abstract As axons from the raphe nuclei densely innervate the somatosensory cortex, we investigated how serotonin (5-HT) modulates transmitter release in layer II pyramidal cells of rat barrel cortex. In the presence of tetrodotoxin and gabazine, 10 μM 5-HT caused a waxing and waning in the frequency of miniature excitatory postsynaptic currents (mEPSC) with no effect on amplitude. Specifically, within 15 min of recording the mEPSC frequency initially increased by 28 ± 7%, then dropped to below control (−15 ± 3%), before resurging back to 27 ± 7% larger than control. These changes were seen in 47% of pyramidal cells (responders) and were mediated by 5-HT2C receptors (5-HT2CR). Waxing resulted from phospholipase C activation, IP3 production, and Ca2+ release from presynaptic stores. Waning was prevented if PKC was blocked. In contrast, in paired recordings, the unitary EPSC amplitude was reduced by 50 ± 3% after 5-HT exposure in almost all cases with no significant effect on paired-pulse ratio and synaptic dynamics. This sustained EPSC reduction was also caused by 5-HT2R, but was mediated by presynaptic Gβγ subunits likely limiting influx through CaV2 channels. EPSC reduction, together with enhanced spontaneous noise in a restricted subset of inputs, could temporarily diminish the signal-to-noise ratio and affect the computation in the neocortical microcircuit.

Some Effects on Light Scattering Intensity and Red Blood Cell Size Distribution Histograms Due to Sphering

1988 ◽  
Vol 25 (6) ◽  
pp. 673-679 ◽  
Author(s):  
P C Bartels ◽  
P W Helleman ◽  
A F M Roijers ◽  
J B J Soons
Keyword(s):  
Light Scattering ◽  
Blood Cell ◽  
Size Distribution ◽  
Red Blood Cell ◽  
Signal To Noise Ratio ◽  
Quantitative Information ◽  
Cell Size Distribution ◽  
Scattering Intensity ◽  
Distribution Ranges ◽  
Light Scattering Intensity

At present most haematology blood cell analysers routinely provide red blood cell (RBC) size distribution histograms. Sophisticated improvements of the instruments have re-awakened interest in the study of size histograms. The quantitative information derived from the histograms may be applied more fruitfully if insight is available, with respect to some essential principles of sizing technology and methods for treatment of RBCs before measurement. In this study the consequences of sphering RBCs are investigated in relation to the generation of size distribution histograms by means of methods based on light scattering intensity (LSI). Sphering of RBCs results in considerably narrower histograms than unsphered RBCs. The overall signal to noise ratio increases and there is a broader gap between large platelets and microcytic RBCs. Narrower size distribution ranges will enable closer modes to be separated. Compared to unsphered RBCs, microcytic sphered RBCs yield increased LSI whereas macrocytic sphered RBCs yield decreased LSI.

scholarly journals Understanding the aerosol information content in multi-spectral reflectance measurements using a synergetic retrieval algorithm

2010 ◽  
Vol 3 (6) ◽  
pp. 1589-1598 ◽  
Author(s):  
D. Martynenko ◽  
T. Holzer-Popp ◽  
H. Elbern ◽  
M. Schroedter-Homscheidt
Keyword(s):  
Content Analysis ◽  
Information Content ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Degrees Of Freedom ◽  
Surface Albedo ◽  
Water Soluble ◽  
Retrieval Algorithm ◽  
Aerosol Types ◽  
Reflectance Measurements

Abstract. An information content analysis for multi-wavelength SYNergetic AErosol Retrieval algorithm SYNAER was performed to quantify the number of independent pieces of information that can be retrieved. In particular, the capability of SYNAER to discern various aerosol types is assessed. This information content depends on the aerosol optical depth, the surface albedo spectrum and the observation geometry. The theoretical analysis is performed for a large number of scenarios with various geometries and surface albedo spectra for ocean, soil and vegetation. When the surface albedo spectrum and its accuracy is known under cloud-free conditions, reflectance measurements used in SYNAER is able to provide for 2–4° of freedom that can be attributed to retrieval parameters: aerosol optical depth, aerosol type and surface albedo. The focus of this work is placed on an information content analysis with emphasis to the aerosol type classification. This analysis is applied to synthetic reflectance measurements for 40 predefined aerosol mixtures of different basic components, given by sea salt, mineral dust, biomass burning and diesel aerosols, water soluble and water insoluble aerosols. The range of aerosol parameters considered through the 40 mixtures covers the natural variability of tropospheric aerosols. After the information content analysis performed in Holzer-Popp et al. (2008) there was a necessity to compare derived degrees of freedom with retrieved aerosol optical depth for different aerosol types, which is the main focus of this paper. The principle component analysis was used to determine the correspondence between degrees of freedom for signal in the retrieval and derived aerosol types. The main results of the analysis indicate correspondence between the major groups of the aerosol types, which are: water soluble aerosol, soot, mineral dust and sea salt and degrees of freedom in the algorithm and show the ability of the SYNAER to discern between this aerosol types. The results of the work will be further used for the development of the promising methodology of the construction error covariance matrices in the assimilation system.

scholarly journals Quantification of uncertainties of water vapour column retrievals using future instruments

2013 ◽  
Vol 6 (2) ◽  
pp. 359-370 ◽  
Author(s):  
H. Diedrich ◽  
R. Preusker ◽  
R. Lindstrot ◽  
J. Fischer
Keyword(s):  
Water Vapour ◽  
Information Content ◽  
Surface Albedo ◽  
Near Infrared ◽  
Single Channel ◽  
High Surface ◽  
Optimal Estimation ◽  
Optimal Position ◽  
Infrared Measurements ◽  
Absorption Channel

Abstract. This study presents a quantification of uncertainties of total column water vapour retrievals based on simulated near-infrared measurements of upcoming instruments. The concepts of three scheduled spectrometers were taken into account: OLCI (Ocean and Land Color Instrument) on Sentinel-3, METimage on an EPS-SG (EUMETSAT Polar System – Second Generation) satellite and FCI (Flexible Combined Imager) on MTG (Meteosat Third Generation). Optimal estimation theory was used to estimate the error of a hypothetical total water vapour column retrieval for 27 different atmospheric cases. The errors range from 100% in very dry cases to 2% in humid cases with a very high surface albedo. Generally, the absolute uncertainties increase with higher water vapour column content due to H2O-saturation and decrease with a brighter surface albedo. Uncertainties increase with higher aerosol optical thickness, apart from very dark cases. Overall, the METimage channel setting enables the most accurate retrievals. The retrieval using the MTG-FCI build-up has the highest uncertainties apart from very bright cases. On the one hand, a retrieval using two absorption channels increases the accuracy, in some cases by one order of magnitude, in comparison to a retrieval using just one absorption channel. On the other hand, a retrieval using three absorption channels has no significant advantage over a two-absorption channel retrieval. Furthermore, the optimal position of the absorption channels was determined using the concept of the "information content". For a single channel retrieval, a channel at 900 or 915 nm has the highest mean information content over all cases. The second absorption channel is ideally weakly correlated with the first one, and therefore positioned at 935 nm, in a region with stronger water vapour absorption.

scholarly journals Optimization of Direct Direction Finding Method with Two-Dimensional Correlative Processing of Spatial Signal

2018 ◽  
Vol 8 ◽  
pp. 46-53
Author(s):  
Vitaliy V. Tsyporenko ◽  
Valentyn G. Tsyporenko
Keyword(s):  
Main Parameter ◽  
Noise Immunity ◽  
Signal To Noise Ratio ◽  
Direction Finding ◽  
High Accuracy ◽  
Signal To Noise ◽  
High Noise ◽  
Spatial Shift ◽  
Simulation Results ◽  
Finding Method

In this article, the main parameter of the correlative-interferometric direction finding method with twodimensional correlative processing of spatial signal in the aperture of a linear antenna array (AA) is determined as the value of spatial shift within the AA aperture. The corresponding objective function is also formed. Analytical optimization of this parameter is presented and a comparative analysis of analytical calculations based on simulation results is conducted. In the simulation, a range of dependencies of the middle square deviation of estimation of direction on the value of the spatial shift for a signal-to-noise ratio of 0 dB, for minimum 3-sample and 4-sample Blackman-Harris windows of the spectral analysis, is received. The value of the middle square deviation of estimation of direction will be minimal and will equal 0.02 degrees using a minimum 3-sample Blackman-Harris window with the −67 dB level of side lobes. It offers high noise immunity and high accuracy of direction finding.

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