scholarly journals Feature of Echo Envelope Fluctuation and Its Application in the Discrimination of Underwater Real Echo and Synthetic Echo

2018 ◽  
Vol 8 (8) ◽  
pp. 1329
Author(s):  
Yunfei Chen ◽  
Sheng Li ◽  
Bing Jia ◽  
Guijuan Li ◽  
Zhenshan Wang
Keyword(s):  
Physical Parameters ◽  
Scaled Model ◽  
Theoretical Simulation ◽  
Active Sonar ◽  
Fluctuation Intensity ◽  
Characterization Model ◽  
Novel Method ◽  
Underwater Target ◽  
Echo Features ◽  
Synthetic Target

Discriminating a real underwater target echo from a synthetic echo is a key challenge to identifying an underwater target. The structure of an echo envelope contains information which closely relates to the physical parameters of the underwater target, and the characterization and extraction of echo features are problematic issues for active sonar target classification. In this study, firstly, the high-frequency envelope fluctuation of a complex underwater target echo was analyzed, the envelope fluctuation was characterized by the envelope fluctuation intensity, and a characterization model was established. The features of a benchmark model echo were extracted and analyzed by theoretical simulation and sea testing of a scaled model, and the result shows that the envelope fluctuation intensity varies with carrier frequency and azimuth of incident signal, but the echo envelope fluctuation of the synthetic target echo does not present these features. Then, based on the characteristics of echo envelope fluctuation, a novel method was developed for active sonar discrimination of a real underwater target echo from the synthetic echo. Through a sea experiment, the real target echo and synthetic echo were classified by their different echo envelope fluctuations, and the feasibility of the method was verified.

scholarly journals Bio-Inspired Covert Active Sonar Strategy

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2436 ◽  
Author(s):  
Jiajia Jiang ◽  
Xianquan Wang ◽  
Fajie Duan ◽  
Chunyue Li ◽  
Xiao Fu ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Estimation Method ◽  
Sperm Whale ◽  
Waveform Design ◽  
Velocity Estimation ◽  
Estimation Methods ◽  
Range Resolution ◽  
Active Sonar ◽  
Ocean Noise ◽  
Underwater Target

The covertness of the active sonar is a very important issue and the sonar signal waveform design problem was studied to improve covertness of the system. Many marine mammals produce call pulses for communication and echolocation, and existing interception systems normally classify these biological signals as ocean noise and filter them out. Based on this, a bio-inspired covert active sonar strategy was proposed. The true, rather than man-made sperm whale, call pulses were used to serve as sonar waveforms so as to ensure the camouflage ability of sonar waveforms. A range and velocity measurement combination (RVMC) was designed by using two true sperm whale call pulses which had excellent range resolution (RR) and large Doppler tolerance (DT). The range and velocity estimation methods were developed based on the RVMC. In the sonar receiver, the correlation technology was used to confirm the start and end time of sonar signals and their echoes, and then based on the developed range and velocity estimation method, the range and velocity of the underwater target were obtained. Then, the RVMC was embedded into the true sperm whale call-train to improve the camouflage ability of the sonar signal-train. Finally, experiment results were provided to verify the performance of the proposed method.

scholarly journals A 2.5D APPROACH TO SKIN WRINKLES SEGMENTATION

2019 ◽  
Vol 38 (1) ◽  
pp. 75 ◽  
Author(s):  
Etienne Decencière ◽  
Amira Belhedi ◽  
Serge Koudoro ◽  
Frédéric Flament ◽  
Ghislain François ◽  
...  
Keyword(s):  
Point Clouds ◽  
Skin Surface ◽  
Fringe Projection ◽  
Physical Parameters ◽  
Projection System ◽  
Beneficial Effects ◽  
3D Point Clouds ◽  
Novel Method ◽  
Skin Wrinkles ◽  
Skin Wrinkling

Wrinkles or creases are common structures on surfaces. Their detection is often challenging, and can be an important step for many different applications. For instance, skin wrinkle segmentation is a crucial step for quantifying changes in skin wrinkling and assessing the beneficial effects of dermatological and cosmetic anti-ageing treatments. A 2.5D approach is proposed in this paper to segment individual wrinkles on facial skin surface described by 3D point clouds. The method, based on mathematical morphology, only needs a few physical parameters as input, namely the maximum wrinkle width, the minimum wrinkle length, and the minimum wrinkle depth. It has been applied to data acquired from eye wrinkles using a fringe projection system. An accurate evaluation was made possible thanks to manual annotations provided by three different experts. Results demonstrate the accuracy of this novel method.

Regulation of the intermittent release of giant unilamellar vesicles under osmotic pressure

2022 ◽  
Author(s):  
Qi Zhou ◽  
Ping Wang ◽  
Bei-Bei Ma ◽  
Zhong-Ying Jiang ◽  
Tao Zhu
Keyword(s):  
Osmotic Pressure ◽  
Line Tension ◽  
Solution Viscosity ◽  
Release Time ◽  
Physical Parameters ◽  
Giant Unilamellar Vesicles ◽  
Unilamellar Vesicles ◽  
Permeable Membrane ◽  
Theoretical Simulation ◽  
Novel Technologies

Abstract Osmotic pressure can break the fluid balance between intracellular and extracellular solutions. In hypo-osmotic solution, water molecules, which transfer into the cell and burst, are driven by the concentrations difference of solute across the semi-permeable membrane. The complicated dynamic processes of the intermittent burst have been previously observed. However, the underlying physical mechanism has yet to be thoroughly explored and analyzed. Here, the intermittent release of inclusion in giant unilamellar vesicles was investigated quantitatively, applying the combination of experimental and theoretical methods in the hypo-osmotic medium. Experimentally, we adopted highly sensitive EMCCD to acquire intermittent dynamic images. Notably, the component of the vesicle phospholipids affected the stretch velocity, and the prepared solution of the vesicle adjusted the release time. Theoretically, we chose equations numerical simulations to quantify the dynamic process in phases and explored the influence of physical parameters such as bilayer permeability and solution viscosity on the process. It was concluded that the time taken to achieve the balance of giant unilamellar vesicles was highly dependent on the structure of the lipid molecular. The pore lifetime was strongly related with the internal solution environment of giant unilamellar vesicles. The vesicle prepared in viscous solution accessed visualized long-lived pore. Furthermore, the line tension was measured quantitatively by the release velocity of inclusion, which was in the same order of magnitude as the theoretical simulation. In all, the experimental values well matched the theoretical values. Our investigation clarified the physical regulatory mechanism of intermittent pore formation and inclusion release, which had an important reference for the development of novel technologies such as gene therapy based on transmembrane transport as well as controlled drug delivery based on liposomes.

Vibration attenuation analysis of compressional gas cushion press nanoimprint lithography system

2013 ◽  
Vol 228 (9) ◽  
pp. 1634-1642 ◽  
Author(s):  
Liu Chaoran ◽  
Yue Jinzhao ◽  
Li Tianhao ◽  
Xia Weiwei ◽  
Li Dongxue ◽  
...  
Keyword(s):  
Nanoimprint Lithography ◽  
Theoretical Models ◽  
Physical Parameters ◽  
Attenuation Effect ◽  
Internal Structures ◽  
Vibration Attenuation ◽  
System Vibration ◽  
Novel Method ◽  
Lithography System ◽  
Great Development

Nanoimprint lithography has a great development in decades. Compressional gas cushion press is a novel method in improving the uniformity in nanoimprint lithography process. Based on compressional gas cushion press nanoimprint lithography system, an attenuation ring is added between the chamber wall and the pedestal. The attenuation ring decreases the influence of system vibration on the fidelity of patterning. The physical parameters of the attenuation material are optimized based on the theoretical models of the vibration attenuation and mechanical calculation. According to the optimization physical parameters, Young's modulus of a perfect material of attenuation ring should be smaller than 8 MPa, and Poisson's ratio should be close to 0.5. Therefore, natural rubber is employed as the material of attenuation ring. The simulation results based on COMSOL indicate that nested rectangular structure has the best attenuation effect among the four simulated internal structures. It provides technological supporting for the establishment of attenuation ring in compressional gas cushion press nanoimprint lithography system.

scholarly journals Spatial evaluation of the apple trees-soil environment

2009 ◽  
Vol 15 (4) ◽  
Author(s):  
J. Tamás
Keyword(s):  
Irrigation System ◽  
Apple Orchard ◽  
Fruit Tree ◽  
Physical Parameters ◽  
Detailed Data ◽  
Soil Environment ◽  
Physical Barriers ◽  
Novel Method ◽  
Micro Irrigation ◽  
The University

Remote sensing of fruit tree micro environment plays a major role in both horticultural and soil mapping applications. In frame this study presented a novel method to survey the spatial distribution of physical and water management properties of soils. The examinations were carried out at an intensive experimental apple orchard in Debrecen-Pallag. The examination site is the part of the Experimental Pomology plantation of the University of Debrecen, Faculty of Agronomy. Particle-size distribution, plasticity according to Arany, metal content by XRF spectrometry, soil physical parameters, acidity, electric conductivity of soils, were measured to obtain appropriate information on the physical properties of the soil. Based on the results, the accurate spatial positions of those sites were characterized where soil loosening should be implemented in 0,3–0,4 m depth. Spatially precise soil physical barriers were determined for applied micro-irrigation system. Based on the micro-element content and pH, the accurate spatial positions of those sites were selected where melioration and micronutrient fertilization is needed. These detailed data sources also applied to calibrate the applied airborne hyperspectral images to extend spatially these point based information.

scholarly journals Correlative all-optical quantification of mass density and mechanics of sub-cellular compartments with fluorescence specificity

eLife ◽  
2022 ◽  
Vol 11 ◽  
Author(s):  
Raimund Schlüßler ◽  
Kyoohyun Kim ◽  
Martin Nötzel ◽  
Anna Taubenberger ◽  
Shada Abuhattum ◽  
...  
Keyword(s):  
Mass Density ◽  
Optical Diffraction ◽  
Physical Parameters ◽  
Implicit Assumption ◽  
Optical Diffraction Tomography ◽  
Quantitative Measurements ◽  
All Optical ◽  
Novel Method ◽  
Cellular Compartments ◽  
Longitudinal Modulus

Quantitative measurements of physical parameters become increasingly important for understanding biological processes. Brillouin microscopy (BM) has recently emerged as one technique providing the 3D distribution of viscoelastic properties inside biological samples - so far relying on the implicit assumption that refractive index (RI) and density can be neglected. Here, we present a novel method (FOB microscopy) combining BM with optical diffraction tomography and epi-fluorescence imaging for explicitly measuring the Brillouin shift, RI and absolute density with specificity to fluorescently labeled structures. We show that neglecting the RI and density might lead to erroneous conclusions. Investigating the nucleoplasm of wild-type HeLa cells, we find that it has lower density but higher longitudinal modulus than the cytoplasm. Thus, the longitudinal modulus is not merely sensitive to the water content of the sample - a postulate vividly discussed in the field. We demonstrate the further utility of FOB on various biological systems including adipocytes and intracellular membraneless compartments. FOB microscopy can provide unexpected scientific discoveries and shed quantitative light on processes such as phase separation and transition inside living cells.

A novel method to determine the coupling scaling laws of vibration characteristics for rotor-bearing systems

2020 ◽  
pp. 107754632096402
Author(s):  
Wendi Zhang ◽  
Zhong Luo ◽  
Yuqi Li ◽  
Yunpeng Zhu
Keyword(s):  
Iteration Method ◽  
Scaling Laws ◽  
Vibration Characteristics ◽  
Scaled Model ◽  
Geometric Scaling ◽  
Rotor Bearing ◽  
Novel Method ◽  
Scaled Models ◽  
Distorted Model ◽  
Bearing System

The purpose of this article is to study the coupling effects of support stiffness on geometric scaling factor powers of the rotor-bearing system and predict vibration characteristics of a prototype by scaled models accurately. Associated to the least-squares–based similitude method, the discrete iteration method proposed evaluates the estimated scaling laws under variable (instable) powers and further broadens the restriction of boundary conditions in scaling laws, which is the main finding in this article. The discrete iteration method does not need to establish a physical model but directly uses input and output parameters to establish output scaling laws. The complete scaled model and geometric distorted model are selected as study cases to prove the effectiveness and accuracy of the discrete iteration method. The vibration characteristics of the rotor-bearing system are obtained by the finite element method with validation by experimental test for the natural characteristics. The comparison between the prediction results and those without the discrete iteration method shows that discrete iteration method can significantly improve the accuracy for predicting the prototype.

scholarly journals Optimal Operating Depth Search for Active Towed Array Sonar using Simulated Annealing

2019 ◽  
Vol 69 (4) ◽  
pp. 415-419
Author(s):  
Sangkyum An ◽  
Keunhwa Lee ◽  
Woojae Seong
Keyword(s):  
Simulated Annealing ◽  
Optimal Solution ◽  
Optimal Operation ◽  
Computational Time ◽  
Performance Function ◽  
Active Sonar ◽  
Optimal Depth ◽  
Towed Array ◽  
Underwater Target ◽  
Ocean Environment

In an active towed array sonar, it is important to find the optimal operation depth. Generally, the optimal depth can be chosen via numerical simulations for all sonar depths and this imposes great burdens of time and cost.In this paper, an efficient approach is proposed to find the optimal depth using the optimisation technique. First, the sonar performance function is newly defined as a measure of how well the active sonar might perform. This function depends on the properties of the ocean environment and the positions of sonar and underwater target. Then, the simulated annealing to find an optimal solution for maximising sonar performance is used. The optimised depth agrees well with the depth obtained from direct searching for all depths of source and receiver combinations, but its computational time is largely reduced.

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