Effective Detection Range Research Articles

Theoretical analysis of potential applications of microwave radar for sandstorm detection

Based on the Rayleigh scattering theory and the meteorological radar equation, in this research, effective detection range has been proposed theoretically to evaluate the working of microwave radar during electrified dust storms. In this regard, the effects of particles concentration and charge quantity of the dust on the performance of microwave radar were analyzed. The results show that particle charges play an integral role in significantly enhancing the radar echoes which signal dust storms, thus making it possible to use microwave radar for dust storm detection. In addition, numerical simulation results have also illustrated that 35 GHz radar is more suitable for remote detection of the vertical structure of a dust layer. In the end, an inversion analysis method used for building the particle concentration profile through radar has been discussed. This study shall prove to be useful in the development of a new monitoring method in the research of sand storms.

Assisting the visually impaired: multitarget warning through millimeter wave radar and RGB-depth sensors

It is very difficult for visually impaired people (VIP) to perceive and avoid obstacles at a distance. To address this problem, we propose a sensor fusion system, which combines the RGB-depth (RGB-D) sensor and millimeter wave (MMW) radar sensor, to perceive the surrounding obstacles. The position and velocity information of the multiple targets are detected by the MMW radar based on the principle of frequency modulated continuous wave. The depth and position information of the obstacles are verified by the RGB-D sensor based on the MeanShift algorithm. The data fusion based on the joint probabilistic data association algorithm and Kalman filter enable the navigation assistance system to obtain more accurate state estimates compared with using only one sensor. The nonsemantic stereophonic interface is utilized to transfer the obstacle detection results to the VIP. The experiment results show that multiple objects with different ranges and angles are detected by the radar and the RGB-D sensor. The effective detection range is expanded up to 80 m compared to using only the RGB-D sensor. Moreover, the measurement results are stable under diverse illumination conditions. As a wearable system, the sensor fusion system has the characteristics of versatility, portability, and cost-effectiveness.

Efficient Lidar Signal Denoising Algorithm Using Variational Mode Decomposition Combined with a Whale Optimization Algorithm

Although lidar is a powerful active remote sensing technology, lidar echo signals are easily contaminated by noise, particularly in strong background light, which severely affects the retrieval accuracy and the effective detection range of the lidar system. In this study, a coupled variational mode decomposition (VMD) and whale optimization algorithm (WOA) for noise reduction in lidar signals is proposed and demonstrated completely. The combination of optimal VMD parameters of decomposition mode number K and quadratic penalty α was obtained by using the WOA and was critical in acquiring satisfactory analysis results for VMD denoising technology. Then, the Bhattacharyya distance was applied to identify the relevant modes, which were reconstructed to achieve noise filtering. Simulation results show that the performance of the proposed VMD-WOA method is superior to that of wavelet transform, empirical mode decomposition, and its variations. Experimentally, this method was successfully used to filter a lidar echo signal. The signal-to-noise ratio of the denoised signal was increased to 23.92 dB, and the detection range was extended from 6 to 10 km.

海雾中舰载红外系统有效探测距离的求解模型

海雾中舰载红外系统有效探测距离的求解模型

A Surface Mass-Spring Model With New Flexion Springs and Collision Detection Algorithms Based on Volume Structure for Real-Time Soft-Tissue Deformation Interaction

A critical problem associated with surgical simulation is balancing deformation accuracy with a real-time performance. Although the canonical surface mass-spring model (MSM) can provide an excellent real-time performance, it fails to provide effective shape restoration behavior when generating large deformations. This significantly influences its deformation accuracy. To address this problem, this paper proposes a modified surface MSM. In the proposed MSM, a new flexion spring is first developed to oppose bending based on the included angle between the initial position vector and the deformational position vector, improving the shape restoration performance, and enhance the deformational accuracy of MSM; then, a new type of surface triangular topological unit is developed for enhancing the computational efficiency and better adapting to the different topological soft tissue deformational models. In addition, to further improve the accuracy of deformational interactions between the soft tissue and surgical instruments, we also propose two new collision detection algorithms. One is the discrete collision detection with the volumetric structure (DCDVS), applying a volumetric structure to extend the effective range of collision detection and the other is the hybrid collision detection with the volumetric structure (HCDVS), introducing the interpolation techniques of the continuous collision detection to DCDVS. Experimental results show that the proposed MSM with the DCDVS or the HCDVS can achieve accurate and stable shape restoration and show the real-time interactive capability in the virtual artery vessel and heart compared with the canonical surface MSM and new volume MSM.

A large Raman scattering cross-section molecular embedded SERS aptasensor for ultrasensitive Aflatoxin B1 detection using CS-Fe3O4 for signal enrichment

With growing concern on oil safety problems, developing a simple and sensitive method to detect Aflatoxin B1 (AFB1), a common mycotoxin in peanut oil, is very necessary. In this study, Surface-enhanced Raman Scattering (SERS) aptasensor was developed for ultrasensitive AFB1 detection using the amino-terminal AFB1 aptamer (NH2-DNA1); and thiol-terminal AFB1 complementary aptamer (SH-DNA2) conjugated magnetic-beads (CS-Fe3O4) as enrichment nanoprobe and AuNR@DNTB@Ag nanorods (ADANRs) as reporter nanoprobe respectively. 5,5′-Dithiobis(2-nitrobenzoicacid) (DNTB) with large Raman scattering cross-section and no fluorescence interference was embedded in Au and Ag core/shell nanorods as Raman reporter molecules. CS-Fe3O4 possessed excellent biocompatibility and superparamagnetism for rapid signal enrichment. Therefore, NH2-DNA1-CS-Fe3O4 and SH-DNA2-ADANRs were fabricated via the hybrid reaction between aptamers and complementary aptamers. When there is AFB1, AFB1 would competitively combine with the NH2-DNA1-CS-Fe3O4 inducing the dissociation of SH-DNA2-ADANRs from CS-Fe3O4 and further decreasing the SERS signal. Based on this developed SERS aptasensor, a low limit of 0.0036ng/mL and an effective linear detection range from 0.01 to 100ng/mL with the correlation coefficient up to 0.986 for AFB1 detection were obtained. Moreover, the specificity of this SERS aptasensor was demonstrated by detecting other two mycotoxins and its accuracy for AFB1 detection in real peanut oil was further confirmed by standard addition recovery test.

The penetrating depth analysis of Lunar Penetrating Radar onboard Chang’e-3 rover

Lunar Penetrating Radar (LPR) has successfully been used to acquire a large amount of scientific data during its in-situ detection. The analysis of penetrating depth can help to determine whether the target is within the effective detection range and contribute to distinguishing useful echoes from noise. First, this study introduces two traditional methods, both based on a radar transmission equation, to calculate the penetrating depth. The only difference between the two methods is that the first method adopts system calibration parameters given in the calibration report and the second one uses high-voltage-off radar data. However, some prior knowledge and assumptions are needed in the radar equation and the accuracy of assumptions will directly influence the final results. Therefore, a new method termed the Correlation Coefficient Method (CCM) is provided in this study, which is only based on radar data without any a priori assumptions. The CCM can obtain the penetrating depth according to the different correlation between reflected echoes and noise. To be exact, there is a strong correlation in the useful reflected echoes and a random correlation in the noise between adjacent data traces. In addition, this method can acquire a variable penetrating depth along the profile of the rover, but only one single depth value can be obtained from traditional methods. Through a simulation, the CCM has been verified as an effective method to obtain penetration depth. The comparisons and analysis of the calculation results of these three methods are also implemented in this study. Finally, results show that the ultimate penetrating depth of Channel 1 and the estimated penetrating depth of Channel 2 range from 136.9 m to 165.5 m () and from 13.0 m to 17.5 m (), respectively.

Rapid quantitation of human epididymis protein 4 in human serum by amplified luminescent proximity homogeneous immunoassay (AlphaLISA)

A sensitive, rapid and homogeneous reaction measurement method for quantitation of human epididymis protein 4 (HE4) in human serum by amplified luminescent proximity homogeneous immunoassay (AlphaLISA) was described. Built on a sandwich-type immunoassay format, analytes in samples were captured by one biotinylated monoclonal antibody combining on the surface of streptavidin coated donor beads, and “sandwiched” by another monoclonal antibody coated on acceptor beads. The coefficient variations of the method were lower than 10%, and the recoveries were in the range of 90–110% for serum samples. A value of 0.88pmol/l was identified as the minimum detectable dose of the present method for HE4. Compared with the results from electrochemiluminescence immunoassay kit (Roche) in 170 serum samples, there was a satisfied correlation coefficient of 0.984. The present assay demonstrated high sensitivity, wider effective detection range and excellent reproducibility for quantitation of HE4 can be useful for early screening and prognosis evaluation of patients with ovarian cancer.

Can you hear me now? Range-testing a submerged passive acoustic receiver array in a Caribbean coral reef habitat.

Submerged passive acoustic technology allows researchers to investigate spatial and temporal movement patterns of many marine and freshwater species. The technology uses receivers to detect and record acoustic transmissions emitted from tags attached to an individual. Acoustic signal strength naturally attenuates over distance, but numerous environmental variables also affect the probability a tag is detected. Knowledge of receiver range is crucial for designing acoustic arrays and analyzing telemetry data. Here, we present a method for testing a relatively large‐scale receiver array in a dynamic Caribbean coastal environment intended for long‐term monitoring of multiple species. The U.S. Geological Survey and several academic institutions in collaboration with resource management at Buck Island Reef National Monument (BIRNM), off the coast of St. Croix, recently deployed a 52 passive acoustic receiver array. We targeted 19 array‐representative receivers for range‐testing by submersing fixed delay interval range‐testing tags at various distance intervals in each cardinal direction from a receiver for a minimum of an hour. Using a generalized linear mixed model (GLMM), we estimated the probability of detection across the array and assessed the effect of water depth, habitat, wind, temperature, and time of day on the probability of detection. The predicted probability of detection across the entire array at 100 m distance from a receiver was 58.2% (95% CI: 44.0–73.0%) and dropped to 26.0% (95% CI: 11.4–39.3%) 200 m from a receiver indicating a somewhat constrained effective detection range. Detection probability varied across habitat classes with the greatest effective detection range occurring in homogenous sand substrate and the smallest in high rugosity reef. Predicted probability of detection across BIRNM highlights potential gaps in coverage using the current array as well as limitations of passive acoustic technology within a complex coral reef environment.

Quantifying Aflatoxin B1 in peanut oil using fabricating fluorescence probes based on upconversion nanoparticles

Rare earth doped upconversion nanoparticles convert near-infrared excitation light into visible emission light. Compared to organic fluorophores and semiconducting nanoparticles, upconversion nanoparticles (UCNPs) offer high photochemical stability, sharp emission bandwidths, and large anti-Stokes shifts. Along with the significant light penetration depth and the absence of autofluorescence in biological samples under infrared excitation, these UCNPs have attracted more and more attention on toxin detection and biological labelling. Herein, the fluorescence probe based on UCNPs was developed for quantifying Aflatoxin B1 (AFB1) in peanut oil. Based on a specific immunity format, the detection limit for AFB1 under optimal conditions was obtained as low as 0.2ng·ml−1, and in the effective detection range 0.2 to 100ng·ml−1, good relationship between fluorescence intensity and AFB1 concentration was achieved under the linear ratios up to 0.90. Moreover, to check the feasibility of these probes on AFB1 measurements in peanut oil, recovery tests have been carried out. A good accuracy rating (93.8%) was obtained in this study. Results showed that the nanoparticles can be successfully applied for sensing AFB1 in peanut oil.

Rapid, sensitive separation of the three main isoflavones in soybean using immunoaffinity chromatography.

Daidzin, genistin, and glycitein are major isoflavone compounds in soybean that are indispensable nutrients in traditional Chinese foods. Generally, strategies for detecting and separating soy isoflavones have been based on HPLC and chromatographic techniques, which are tedious and time-consuming procedures. In the present study, we developed an ELISA-based approach for daidzin detection using a broad-specificity monoclonal antibody (clone number: AA9) with an effective detection range of 10-10 000 ng/mL. Subsequently, we prepared an immunoaffinity column by coupling the monoclonal antibody AA9 to CNBr-activated Sepharose 4B. Our results demonstrate that the immunoaffinity column can efficiently and specifically extract daidzin, glycitein, and genistin from numerous structurally similar soy isoflavones in leguminous plants, thereby providing a new method for the extraction of target components from similar compounds in natural products.

Baffling telemetry detections can be useful: an acoustic receiver design to monitor organisms along reserve boundaries and ecotones

Many biotelemetry studies seek to detect movement of organisms across reserve boundaries or between adjacent habitat areas. Our objective was to enhance this capability in studies of aquatic organisms that are tagged with acoustic transmitters and tracked by passive data loggers. We installed an experimental shroud on a commercially available telemetry receiver. The shroud was designed to baffle incoming signals from transmitters along one hemisphere of the receiver and therefore more conclusively determine which side of a boundary line that a tagged organism occupies. Range testing of shroud effectiveness was conducted along the border of a marine-protected area in a coral reef ecosystem. A transmitter of the type implanted into reef fish was deployed in various directions, distances, and landscape settings relative to 11 shrouded receivers. There was a significant difference in the detectability of transmissions on the shrouded versus unshrouded side of the receivers. On the unshrouded hemisphere of the receiver, 75–100 % of transmissions within 100 m were detected and maximum effective detection range was ~180 m. On the shrouded hemisphere of the receiver, detections were rare at any distance with a maximum of 12 % of transmissions recorded even as close as 60 m away. The shroud modified the detection area of a standard omni-directional receiver into a hemi-directional receiver better able to detect transboundary presence. The approach is useful for applications that require detection of simple boundary-crossing events using a minimal number of receivers.

Automatic microfluidic fluorescence-array measurement system for detecting organic phosphate.

In this study, an automatic microfluidic fluorescence-array measurement system is developed to detect the concentration of organic phosphate based on the luminol-hydrogen peroxide catalytic fluorescent mechanism. Not only sample quantity and cost can be reduced, but also detection time, accuracy and precision can be improved in the system. The system is composed of a CCD image module, a stepper motor with driver, a microfluidic fluorescence array, a background light elimination module, and a dynamic image-analyzed interface. The pesticides of chlorpyrifos and fenitrothion of organic phosphate are chosen as experimental samples. Only a 2.5 μ l quantity of sample is required to have a fast response time of 1.4 second. Experimental results show that the sensitivities of chlorpyrifos and fenitrothion are 1.88 V/ppm in the range of 0.166 ∼ 10 ppm with averaged error of 1.66% and 0.32 V/ppm in the range of 0.03 ∼ 10 ppm with averaged error of 1.68% respectively. The organophosphorus effective detection range of the developed system covers the legal prescription for pesticide residues.

Optofluidic multi-measurement system for the online monitoring of lubricant oil

We show a detection system that simultaneously allows absorbance (ABS), laser-induced fluorescence (LIF) and scattering detection excited by two different laser sources at 405 nm and 450 nm. The heart of the system consists of a mass manufacturable polymer optofluidic chip. The chip is mounted in an optical detection assembly that aligns the chip to the rest of the system, seals the chip from leakage, fixes the position and connects the channels to the rest of the fluidic system. The fluidics exhibit a reduced susceptibility to perturbations caused by air bubbles, this is accomplished by making use of a serpentine channel layout. For coumarin 480, detection limits of 100 nM and 10 pM are observed for ABS and LIF respectively. An effective detection range of 4000 down to 1 nephelometric turbidity units is shown for the detection of scattered light. The viscous behaviour of the sample is analysed by a secondary FFT processing step of which the result is further processed by multivariate data analysis. This allows the identification of samples and prediction of their quality parameters. We apply this system for the monitoring of lubricant oil, demonstrating its ability to compete with spectroscopic detection techniques. The low-cost approach and multi-measurement architecture shown in this paper pave the way for miniaturized on-line monitoring of liquids in an industrial environment.

Close proximity detection interference with acoustic telemetry: the importance of considering tag power output in low ambient noise environments

When employing acoustic telemetry to study aquatic species, understanding the functional dynamics of the monitoring system is essential for effective study design, data interpretation, and analysis. Typically, researchers are concerned with maximum effective detection range and consequently tend to employ the largest most powerful tags the study species can carry without considerable energetic burden. In ideal acoustic conditions of low ambient noise environments, low attenuation, and reflective structure, higher powered tags can be detected at larger distances from the receiver, but they can also be subject to the phenomenon ‘Close Proximity Detection Interference’ (CPDI). This occurs when reflective barriers, such as a calm water surface and/or hard substrate, result in strong transmission echoes that interfere with the transmission sequence. As a result, transmissions in close proximity to the receiver are not effectively decoded and logged. CPDI was assessed from the results of three detection range tests conducted using the Vemco 69 kHz telemetry system in three contrasting study systems: a sheltered marine Arctic embayment, a temperate freshwater lake, and an exposed marine sub-tropical reef line. For the Arctic embayment, CPDI was absent with the lower power V9 tag (90% of transmissions received at 55 m) but was recorded for the V13 tag and was most prevalent for the highest power V16 tag (18% and 8% of transmissions received at 55 m, respectively). Comparing V16 tag detection profiles between study systems, CPDI was evident in the low ambient noise Arctic embayment and temperate freshwater lake (highest transmission proportions recorded at 370 and 207 m, respectively) but was absent on the high ambient noise sub-tropical reef line. Functional examples highlight the ways in which CPDI can affect different study designs if not acknowledged or accounted for. CPDI was shown to be the most prominent in low ambient noise study systems and should be considered when choosing tag type/power during study design. If unaccounted for, CPDI could lead to misinterpretation during the analysis of acoustic telemetry data. The identification of CPDI highlights the complexities associated with the functionality of acoustic telemetry systems and supports recommendations for thorough detection range testing.

A magnetic nanoparticle-based time-resolved fluoroimmunoassay for determination of the cytokeratin 19 fragment in human serum.

A sensitive, rapid and novel measurement method for cytokeratin 19 fragment (CYFRA 21-1) in human serum by magnetic particle-based time-resolved fluoroimmunoassay (TRFIA) is described. Built on a sandwich-type immunoassay format, analytes in samples were captured by one monoclonal antibody coating onto the surface of magnetic beads and "sandwiched" by another monoclonal antibody labeled with europium chelates. The coefficient variations of the method were lower than 7%, and the recoveries were in the range of 90-110% for serum samples. The lower limit of quantitation of the present method for CYFRA 21-1 was 0.78 ng/ml. The correlation coefficient of CYFRA 21-1 values obtained by our novel TRFIA and CLIA was 0.980. The present novel TRFIA demonstrated high sensitivity, wider effective detection range and excellent reproducibility for determination of CYFRA 21-1 can be useful for early screening and prognosis evaluation of patients with non-small cell lung cancer.

Automated tracking of wild hummingbird mass and energetics over multiple time scales using radio frequency identification (RFID) technology

We examined the feasibility of automating the collection of hummingbird mass data facilitated by low‐cost, low‐power radio frequency identification (RFID) technology. In a field study in southern Ontario, wild hummingbirds were captured, subcutaneously implanted with passive integrated transponder (PIT) tags, and released over a three‐year period. Tagged hummingbirds were detected at specially designed feeder stations outfitted with low‐cost, low‐power RFID readers coupled with a perch secured to a digital balance. When tagged birds visited the feeder, transponder detection initiated the recording of the perched hummingbird's mass at regular intervals continuing as long as the bird remained. This permitted a nearly continuous record of mass during each visit. Mass data collected from tagged hummingbirds showed consistent trends at multiple temporal scales: the individual feeder visit, single days, and even whole seasons. These results further confirm that RFID technology is safe for use in the smallest birds. The effective detection range is a function of RFID reader power, antenna, and tag size. Yet, we find that careful arrangement of feeders and detectors allows for reliable detection even when detection range is low. When coupled with additional technologies, such as a precision electronic balance, this approach can yield robust serial measures of physiological parameters such as mass, an indicator of energy balance over time.

Sector wise echoes study and climatology around Jaisalmer

The capability of Weather Radar to see through the thunder clouds and rain has made it a unique observation tool for remotely surveying the atmosphere. Pulsed radar technique has been applied with remarkable success to map the rain field of various duration and intensities along with movement of storms in real time within the effective detection range of radar. It is a very good tool for forecaster to provide better warning for impending storms and heavy rainfall over the area under radar surveillance and thereby losses due to storm can be minimized while their benefits can be continued like water resource management. In the present work attention has been focused on conducting a comprehensive study of frequencies of occurrence of echoes around Jaisalmer up to 200 km from radar site and the surrounding of it has divided into four equal sectors, i.e., sector-1 (NW, 270°-360° ) , sector-2 (NE, 0°-90°) , sector-3 (SE, 90°-180° ) and sector-4 (SW, 180°-270°). Total number of echoes under the study was 28918 for the period from 19th April, 1993 to 31st December, 2010. Total number of echoes analyzed in Sector-1, were 5441(18.8%), in sector-2, number of echoes analyzed were 9554(33.0%), in sector-3, number of echoes analyzed were 9479 (32.8%) and in sector-4, number of echoes analyzed were 4444(15.4%). Radar echoes to be classified month-wise and the lowest number of average echoes observed in the month of December was 0.4%, in the month of November 0.5%, in October and March 1.6% and in the month of January and February 2.0% .The highest number of annual average echoes observed in the month of July was 30.1% followed by August 24.6%, June 17.2%, May 8.3%, April 6.3% and September 5.8%. Height wise echoes analyzed and the highest number of echoes found for 3 km in all the four sectors were 29.0% and the lowest were for 16 km as 0.2%.

Bird Radar Validation in the Field by Time-Referencing Line-Transect Surveys

Track-while-scan bird radars are widely used in ornithological studies, but often the precise detection capabilities of these systems are unknown. Quantification of radar performance is essential to avoid observational biases, which requires practical methods for validating a radar’s detection capability in specific field settings. In this study a method to quantify the detection capability of a bird radar is presented, as well a demonstration of this method in a case study. By time-referencing line-transect surveys, visually identified birds were automatically linked to individual tracks using their transect crossing time. Detection probabilities were determined as the fraction of the total set of visual observations that could be linked to radar tracks. To avoid ambiguities in assigning radar tracks to visual observations, the observer’s accuracy in determining a bird’s transect crossing time was taken into account. The accuracy was determined by examining the effect of a time lag applied to the visual observations on the number of matches found with radar tracks. Effects of flight altitude, distance, surface substrate and species size on the detection probability by the radar were quantified in a marine intertidal study area. Detection probability varied strongly with all these factors, as well as species-specific flight behaviour. The effective detection range for single birds flying at low altitude for an X-band marine radar based system was estimated at ∼1.5 km. Within this range the fraction of individual flying birds that were detected by the radar was 0.50±0.06 with a detection bias towards higher flight altitudes, larger birds and high tide situations. Besides radar validation, which we consider essential when quantification of bird numbers is important, our method of linking radar tracks to ground-truthed field observations can facilitate species-specific studies using surveillance radars. The methodology may prove equally useful for optimising tracking algorithms.

An endoscopic diffuse optical tomographic method based on the effective detection range

Endoscopic diffuse optical tomography (DOT) is a new medical imaging modality with the potential applications in functional imaging of the internal organs. To cut down the measurement time and the computation burden of image reconstruction, in this paper, we developed the image reconstruction algorithm with the partial measurement in the effective detection range (EDR) of a tubular tissue and the corresponding endoscopic imaging system with a novel endoscopic probe for flexibly selecting the detection sites. For a typical inner size and optical properties of the cervix, it is found that EDR is less than half of the inner circumference. Comparing to the traditional method, the adoption of EDR results in a reduction of more than a factor of two in the time cost for a measurement cycle and for the total iteration reconstruction. Images reconstructed from the simulation data demonstrate that the proposed method achieves equivalent image quality to that obtained from the complete data set. The images reconstructed from the EDR measurements on cervix-like solid phantoms show that both the location and size of the targets are reconstructed correctly. The proposed method will be useful to the development of endoscopic DOT technologies for cancer detection in tubular organs including cervix.