scholarly journals Теоретичні основи побудови багаточастотних радіометричних комплексів для виявлення БпЛА на тлі атмосферного випромінювання

2021 ◽  
pp. 74-82
Author(s):  
Микола Вікторович Руженцев ◽  
Семен Сергійович Жила ◽  
Володимир Володимирович Павліков ◽  
Гліб Сергійович Черепнін ◽  
Анатолій Владиславович Попов ◽  
...  
Keyword(s):  
Detection Threshold ◽  
Correct Detection ◽  
Optimal Method ◽  
Highly Sensitive ◽  
Signal Processing Algorithms ◽  
Atmospheric State ◽  
State Size ◽  
Technical Solutions ◽  
Theoretical Foundations ◽  
Theoretical Results

Due to the impossibility of hiding the unmanned aerial vehicles (UAV) own radiothermal radiation or reducing its contrast against the background of atmospheric radiation, it is advisable to use highly sensitive radiometric receivers to solve the detection problem. The optimal method for complexing the results of measurements in multichannel radiometric receivers and identifying different types and classes of UAV against the sky in X, Ka, and W wave ranges under different meteorological conditions has been developed. end-to-end optimization of methods and algorithms will reveal the theoretical foundations of the construction of radiometric systems, ranging from the field of registration of electromagnetic fields to the final stages. In cloudless and clear weather, radiometric measurements in the W range will allow to obtain high-precision estimates of the spatial position of UAVs, in the X range of reliable observations in rain, snow, fog. The use of the Ka-band receiver in the radiometric complex will allow to realize the best sensitivity due to the technical achievements of domestic production in the creation of broadband radiometric receivers in this waveband. Studies of the main parameters of UAV detection have been conducted, namely, the probability of erroneous detection alarm and the probability of correct detection. The obtained theoretical results allow to determine signal processing algorithms and optimal structures of radiometric receivers, to analyze the maximum measurement error and to develop recommendations for experiments. Having received a database of radiometric contrasts, it is possible to further implement technical solutions to increase the capabilities of airspace monitoring for UAV detection. Recommendations are given for the practical choice of the UAV detection threshold to ensure the probability of correct detection is not worse than 0.9 for different angles of observation, atmospheric state, size and material of manufacture.

scholarly journals Antibody testing for COVID-19: A report from the National COVID Scientific Advisory Panel

2020 ◽  
Vol 5 ◽  
pp. 139 ◽  
Author(s):  
Emily R. Adams ◽  
Mark Ainsworth ◽  
Rekha Anand ◽  
Monique I. Andersson ◽  
Kathryn Auckland ◽  
...  
Keyword(s):  
Symptom Onset ◽  
Vaccine Development ◽  
Detection Threshold ◽  
Negative Control ◽  
Antibody Detection ◽  
Advisory Panel ◽  
Antibody Testing ◽  
Highly Sensitive ◽  
History Of ◽  
The Uk

Background: The COVID-19 pandemic caused >1 million infections during January-March 2020. There is an urgent need for reliable antibody detection approaches to support diagnosis, vaccine development, safe release of individuals from quarantine, and population lock-down exit strategies. We set out to evaluate the performance of ELISA and lateral flow immunoassay (LFIA) devices. Methods: We tested plasma for COVID (severe acute respiratory syndrome coronavirus 2; SARS-CoV-2) IgM and IgG antibodies by ELISA and using nine different LFIA devices. We used a panel of plasma samples from individuals who have had confirmed COVID infection based on a PCR result (n=40), and pre-pandemic negative control samples banked in the UK prior to December-2019 (n=142). Results: ELISA detected IgM or IgG in 34/40 individuals with a confirmed history of COVID infection (sensitivity 85%, 95%CI 70-94%), vs. 0/50 pre-pandemic controls (specificity 100% [95%CI 93-100%]). IgG levels were detected in 31/31 COVID-positive individuals tested ≥10 days after symptom onset (sensitivity 100%, 95%CI 89-100%). IgG titres rose during the 3 weeks post symptom onset and began to fall by 8 weeks, but remained above the detection threshold. Point estimates for the sensitivity of LFIA devices ranged from 55-70% versus RT-PCR and 65-85% versus ELISA, with specificity 95-100% and 93-100% respectively. Within the limits of the study size, the performance of most LFIA devices was similar. Conclusions: Currently available commercial LFIA devices do not perform sufficiently well for individual patient applications. However, ELISA can be calibrated to be specific for detecting and quantifying SARS-CoV-2 IgM and IgG and is highly sensitive for IgG from 10 days following first symptoms.

scholarly journals Antibody testing for COVID-19: A report from the National COVID Scientific Advisory Panel

2020 ◽  
Author(s):  
◽  
Emily R Adams ◽  
Mark Ainsworth ◽  
Rekha Anand ◽  
Monique I Andersson ◽  
...  
Keyword(s):  
Symptom Onset ◽  
Vaccine Development ◽  
Detection Threshold ◽  
Negative Control ◽  
Antibody Detection ◽  
Advisory Panel ◽  
Antibody Testing ◽  
Highly Sensitive ◽  
History Of ◽  
The Uk

ABSTRACTBackgroundThe COVID-19 pandemic caused >1 million infections during January-March 2020. There is an urgent need for reliable antibody detection approaches to support diagnosis, vaccine development, safe release of individuals from quarantine, and population lock-down exit strategies. We set out to evaluate the performance of ELISA and lateral flow immunoassay (LFIA) devices.MethodsWe tested plasma for COVID (SARS-CoV-2) IgM and IgG antibodies by ELISA and using nine different LFIA devices. We used a panel of plasma samples from individuals who have had confirmed COVID infection based on a PCR result (n=40), and pre-pandemic negative control samples banked in the UK prior to December-2019 (n=142).ResultsELISA detected IgM or IgG in 34/40 individuals with a confirmed history of COVID infection (sensitivity 85%, 95%CI 70-94%), vs. 0/50 pre-pandemic controls (specificity 100% [95%CI 93-100%]). IgG levels were detected in 31/31 COVID-positive individuals tested ≥10 days after symptom onset (sensitivity 100%, 95%CI 89-100%). IgG titres rose during the 3 weeks post symptom onset and began to fall by 8 weeks, but remained above the detection threshold. Point estimates for the sensitivity of LFIA devices ranged from 55-70% versus RT-PCR and 65-85% versus ELISA, with specificity 95-100% and 93-100% respectively. Within the limits of the study size, the performance of most LFIA devices was similar.ConclusionsCurrently available commercial LFIA devices do not perform sufficiently well for individual patient applications. However, ELISA can be calibrated to be specific for detecting and quantifying SARS-CoV-2 IgM and IgG and is highly sensitive for IgG from 10 days following first symptoms.

scholarly journals Game Theoretical Method for Anomaly-Based Intrusion Detection

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Zhiyong Wang ◽  
Shengwei Xu ◽  
Guoai Xu ◽  
Yongfeng Yin ◽  
Miao Zhang ◽  
...  
Keyword(s):  
Intrusion Detection ◽  
Detection Threshold ◽  
Optimal Strategies ◽  
Theoretical Method ◽  
Intrusion Detection Systems ◽  
Analysis Method ◽  
Detection Systems ◽  
Second Stage ◽  
Theoretical Results ◽  
Attack Intensity

In this paper, the game theoretical analysis method is presented to provide optimal strategies for anomaly-based intrusion detection systems (A-IDS). A two-stage game model is established to represent the interactions between the attackers and defenders. In the first stage, the players decide to do actions or keep silence, and in the second stage, attack intensity and detection threshold are considered as two important strategic variables for the attackers and defenders, respectively. The existence, uniqueness, and explicit computation of the Nash equilibrium are analyzed and obtained by considering six different scenarios, from which the optimal detection and attack actions are provided. Numerical examples are provided to validate our theoretical results.

PASSIVE RADIOLOCATION. DISTANCE ESTIMATION METHODS

2021 ◽  
Vol 17 (1) ◽  
pp. 111-118
Author(s):  
Pătru PÎRJOL
Keyword(s):  
Signal Processing ◽  
Sensor Networks ◽  
Scientific Community ◽  
Distance Estimation ◽  
Estimation Methods ◽  
Passive Radar ◽  
Signal Processing Algorithms ◽  
Processing Algorithms ◽  
Areas Of Interest ◽  
Technical Solutions

Abstract: The timely discovery of existing threats in the airspace is a permanent concern of the relevant military powers of this century and sensor networks have been developed in this regard, arranged over very large geographical areas in order to achieve a permanent and continuous surveillance of the areas of interest. Research conducted by the scientific community has demonstrated the potential of bistatic (passive) radar as a means of surveillance, the efforts focusing on improving receiver parameters and signal processing algorithms. An important role in these scientific approaches is played by the geodetic distance estimation methods, as well as by the diversification of technical solutions that provide the necessary support for their application and the establishment of algorithms for refining the data provided.  

scholarly journals Terahertz real-time imaging uncooled array based on antenna- and cavity-coupled bolometers

2014 ◽  
Vol 372 (2012) ◽  
pp. 20130111 ◽  
Author(s):  
François Simoens ◽  
Jérôme Meilhan
Keyword(s):  
Real Time ◽  
Direct Detection ◽  
Detection Threshold ◽  
Complementary Metal Oxide Semiconductor ◽  
Industrial Applications ◽  
Oxide Semiconductor ◽  
Thz Radiation ◽  
Quarter Wavelength ◽  
Highly Sensitive ◽  
Thz Range

The development of terahertz (THz) applications is slowed down by the availability of affordable, easy-to-use and highly sensitive detectors. CEA-Leti took up this challenge by tailoring the mature infrared (IR) bolometer technology for optimized THz sensing. The key feature of these detectors relies on the separation between electromagnetic absorption and the thermometer. For each pixel, specific structures of antennas and a resonant quarter-wavelength cavity couple efficiently the THz radiation on a broadband range, while a central silicon microbridge bolometer resistance is read out by a complementary metal oxide semiconductor circuit. 320×240 pixel arrays have been designed and manufactured: a better than 30 pW power direct detection threshold per pixel has been demonstrated in the 2–4 THz range. Such performance is expected on the whole THz range by proper tailoring of the antennas while keeping the technological stack largely unchanged. This paper gives an overview of the developed bolometer-based technology. First, it describes the technology and reports the latest performance characterizations. Then imaging demonstrations are presented, such as real-time reflectance imaging of a large surface of hidden objects and THz time-domain spectroscopy beam two-dimensional profiling. Finally, perspectives of camera integration for scientific and industrial applications are discussed.

scholarly journals CHROMIUM AND NICKEL IN SOIL IN THE WIDER MAGLAJ AREA – CONCENTRATION AND GENESIS

2017 ◽  
Vol 1 (17) ◽  
Author(s):  
Elvir Babajić ◽  
Alisa Babajić ◽  
Željka Stjepić Srkalović ◽  
Dado Srkalović ◽  
Samir Ustalić ◽  
...  
Keyword(s):  
Detection Threshold ◽  
Laboratory Method ◽  
Source Rocks ◽  
Hazardous Substances ◽  
Icp Ms ◽  
Highly Sensitive ◽  
High Concentrations ◽  
Highly Sensitive Detection

Research on potentially toxic elements chromium and nickel and laboratory testing of theirconcentrations was carried out in the wider area of Maglaj, with the aim to detect and determine theirquantities, which gave basis for discussion about origins of these pollutants in soil. Field and laboratoryobservations included 45 soil samples, taken by the network, which is dictated by geomorphologicalconditions. The most frequently sampled type of soil are fluvisol and humofluvisol. Concentration ofchromium (Cr) and nickel (Ni) are obtained by the most sophisticated laboratory method (ICP-MS),with a highly sensitive detection threshold (0.1 to 10,000 ppm).Evaluation of test results showed that concentrations of Cr (max. 954 ppm, min 154 ppm, average 457.5pmm) and Ni (max 504.5 ppm, min 103.5 ppm; average 275.57 pmm) are significantly increasedcompared to the concentrations prescribed in the Regulations on determination of allowed amounts ofharmful and hazardous substances in soil (Cr max = 100 ppm and Ni max = 50 ppm). Consideringgeological settings of surrounding area (the dominant presence of igneous ultramafic and mafic rocks) itcan be concluded that high concentrations of Cr and Ni have geogenic origins, what is mean that theyoriginate from source rocks from which they are separated through the long-term decomposition anddisintegration processes.

scholarly journals Comparison of FoodChek E. coli Test and AOAC Research Institute Performance Tested Method 010603 for Detection of E. coli O157 in Raw Ground Beef

2010 ◽  
Vol 93 (3) ◽  
pp. 922-927 ◽  
Author(s):  
Richard J Flanagan ◽  
Gabriela Martinez
Keyword(s):  
Magnetic Nanoparticle ◽  
Raw Materials ◽  
Detection System ◽  
Detection Threshold ◽  
Reference Method ◽  
Superparamagnetic Nanoparticles ◽  
E Coli ◽  
Detection Assay ◽  
Highly Sensitive ◽  
Research Institute

Abstract The FoodChek E. coli O157 assay [AOAC Research Institute (RI) Performance Tested Method (PTM) 060902] is a rapid detection system that incorporates the use of antibody-coated superparamagnetic nanoparticles in a lateral flow immunoassay format. The system comprises a commercially available enrichment medium, a magnetic nanoparticle immunoassay, and an automated reader for detection. Assay detection threshold is improved relative to traditional immunoassays through use of a magnetic nanoparticle label and a highly sensitive magnetic particle detector. FoodChek E. coli O157 is a reintroduction of the previously certified AOAC PTM 010603. The original assay was evaluated and approved in internal and independent laboratory studies. Vacci-Test Corp. has contracted with the original supplier of the PTM to remanufacture the test under identical conditions and with identical raw materials. This report is intended to show that FoodChek E. coli is identical in performance to the previously approved PTM. The results showed no difference for the parameters evaluated. Three kit lots along with three lots of media and media supplement were compared in lot-to-lot and stability testing. The results indicated no difference in performance across the three lots. The results showed sensitivity of >99 and a specificity rate of >98 for the FoodChek method and a significantly higher sensitivity than the reference method.

scholarly journals Multi-MeV Flash Radiography in Shock Physics Experiments: Specific Assemblages of Monolithic Scintillating Crystals for Use in CCD-Based Imagers

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
D. Partouche-Sebban ◽  
I. Abraham ◽  
S. Lauriot ◽  
C. Missault
Keyword(s):  
Noise Level ◽  
Detection Threshold ◽  
Ccd Camera ◽  
Low Noise ◽  
Stopping Power ◽  
Bremsstrahlung Spectrum ◽  
Shock Physics ◽  
Visible Image ◽  
Highly Sensitive ◽  
Physics Experiments

We have developed a new CCD-based radiographic camera called CrystalEyeCam for use in shock physics experiments: it is composed of two turning mirrors and an objective to relay the (visible) image from a scintillator assembly to a highly sensitive, low noise CCD camera. The objective was specifically developed to match our needs and has few chromatic and geometric aberrations and high photometric performance. The scintillator assembly is constructed using a specific (patented) technique of assembling monolithic scintillating crystals. It replaces the segmented scintillator previously used at our facility and produces higher quality images (better resolution and no segmentation). The sensitivity, noise level, detection threshold and resolution of CrystalEyeCam were measured using an 18-MeV-bremsstrahlung spectrum, filtered with 10 cm of lead, and two BGO assemblies: 20 and 30 mm in thickness, respectively. In particular, with the 30 mm-thick BGO assembly, the measured detection threshold of the imager (at ) is 1 μGy(air) and its resolution is ~1 mm. For 4-MeV incident photons, the estimated (energy) stopping power of the scintillator is 41%. The scintillator assembly thus proved to be a cheaper, effective alternative to segmented scintillators for use in CrystalEyeCam.

scholarly journals Measuring the H i mass function below the detection threshold

2019 ◽  
Author(s):  
Hengxing Pan ◽  
Matt J Jarvis ◽  
James R Allison ◽  
Ian Heywood ◽  
Mario G Santos ◽  
...  
Keyword(s):  
Flux Density ◽  
Noise Level ◽  
Background Noise ◽  
Detection Threshold ◽  
Mass Function ◽  
Emission Lines ◽  
Mass Limit ◽  
Survey Area ◽  
Optimal Method ◽  
Different Levels

Abstract We present a Bayesian stacking technique to directly measure the H i mass function (HIMF) and its evolution with redshift using galaxies formally below the nominal detection threshold. We generate galaxy samples over several sky areas given an assumed HIMF described by a Schechter function and simulate the H i emission lines with different levels of background noise to test the technique. We use Multinest to constrain the parameters of the HIMF in a broad redshift bin, demonstrating that the HIMF can be accurately reconstructed, using the simulated spectral cube far below the H i mass limit determined by the 5σ flux-density limit, i.e. down to MHI = 107.5 M⊙ over the redshift range 0 < z < 0.55 for this particular simulation, with a noise level similar to that expected for the MIGHTEE survey. We also find that the constraints on the parameters of the Schechter function, φ⋆, M⋆ and α can be reliably fit, becoming tighter as the background noise decreases as expected, although the constraints on the redshift evolution are not significantly affected. All the parameters become better constrained as the survey area increases. In summary, we provide an optimal method for estimating the H i mass at cosmological distances that allows us to constrain the H i mass function below the detection threshold in forthcoming H i surveys. This study is a first step towards the measurement of the HIMF at high (z > 0.1) redshifts.

scholarly journals COPPER (Cu) DISTRIBUTION IN TUZLA'S TOPSOILS

2018 ◽  
Vol 1 (19) ◽  
Author(s):  
Željka Stjepić Srkalović
Keyword(s):  
Anthropogenic Impacts ◽  
Detection Threshold ◽  
Soil Sampling ◽  
Sensitive Detection ◽  
Sampling Network ◽  
Icp Ms ◽  
Highly Sensitive ◽  
Highly Sensitive Detection ◽  
The Town

The main goal of the research was to determine to which extent the copper (Cu) is dominant in the topsoils ofTuzla's area. Considering the defined goal, the detailed soil analyze for the presence of this element in thearea of Tuzla, was carried out. The terrain work was based on soil sampling (240 samples) from the area ofabout 303 km2. The sampling network for the urban part of the town was 1x1 km, and for the rural part1,5x1,5 km and according to URGE instructions. The Cu concentrations are obtained by the most sophisticatedlaboratory method (ICP-MS), with a highly sensitive detection threshold (0.02 to 10,000 ppm). Elevatedconcentrations of copper in the Tuzla’s topsoil are recorded in 64 samples. The copper concentrations in thesesamples ranges from 50 ppm to 156,1 ppm. Highly exceeded concentrations are recorded in samples No: 64,66, 163, 170, 171, 182, 187, 195, 214 and 249a, located mostly in the western part of the Tuzla. The increasedconcentrations copper are primarily a consequence of anthropogenic impacts in enviroment.

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