scholarly journals Marine UAV–USV Marsupial Platform: System and Recovery Technic Verification

2020 ◽  
Vol 10 (5) ◽  
pp. 1583 ◽  
Author(s):  
Hongda Zhang ◽  
Yuqing He ◽  
Decai Li ◽  
Feng Gu ◽  
Qi Li ◽  
...  
Keyword(s):  
Physical Simulation ◽  
Current System ◽  
Accurate Estimation ◽  
Unmanned Systems ◽  
Mobile Platforms ◽  
Practical Applications ◽  
Heterogeneous Platform ◽  
Short Period ◽  
Recovery System ◽  
Autonomous Recovery

Heterogeneous unmanned systems consisting of unmanned aerial vehicles (UAVs) and unmanned surface vehicles (USVs) have great application potential in marine environments. At present, the fully autonomous recovery of UAVs is a key problem that restricts any significant application of a heterogeneous unmanned system. This paper presents a novel fully autonomous recovery system, covering the entire process of recovery of small fixed-wing UAVs on mobile platforms at sea. We describe methods or solutions for the key problems encountered by the current system, including active modeling of the UAV–USV heterogeneous platform motion model, accurate estimation of the highly dynamic relative motion of the heterogeneous platform, dynamic analysis of the arresting cable system, and compliance control of the manipulator recovery system. Based on these methods, a physical simulation platform for the fully autonomous recovery system, including an actively adjustable arresting cable, manipulator compliance recovery system, and other subsystems, is developed and verified through experiments. The experiments show that the system proposed in this study can achieve full autonomous recovery of a small ship-based fixed-wing UAV with a high success rate in a short period. This system is the foundation for practical applications of UAV–USV heterogeneous unmanned systems in the marine environment.

Immunoenhancement of Recombinant Neisseria meningitides PorB Protein on Porcine Circovirus Type 2 and Mycoplasma hyopneumoniae Genetically Engineered Vaccines

2019 ◽  
Vol 26 (10) ◽  
pp. 776-784
Author(s):  
Rui Yang ◽  
Yu Tao ◽  
Gaojian Li ◽  
Jian Chen ◽  
Jianhong Shu ◽  
...  
Keyword(s):  
Recombinant Protein ◽  
Mycoplasma Hyopneumoniae ◽  
Porcine Circovirus Type ◽  
Porcine Circovirus Type 2 ◽  
Genetically Engineered ◽  
Porcine Circovirus ◽  
Practical Applications ◽  
Neisseria Meningitides ◽  
Short Period

Background:Porcine circovirus and Mycoplasma hyopneumoniae can cause respiratory diseases in pigs, which cause serious economic loss in the worldwide pig industry. Currently, these infections are mainly prevented and controlled by vaccination. The new vaccines on the market are mainly composed of subunits and inactivated vaccines but usually have lower antigenicity than traditional live vaccines. Thus, there is an increasing need to develop new adjuvants that can cause rapid and long-lasting immunity to enhance the antigenic efficacy for vaccines. Studies have shown that meningococcal porin PorB can act as a ligand to combine with Toll-like receptors to activate the production of immunological projections and act as a vaccine immunological adjuvant.Objective:In this article, we expressed and purified the recombinant PorB protein and verified its immunogenicity against porcine circovirus type 2 and Mycoplasma hyopneumoniae genetically engineered vaccine.Methods:In this article, we used prokaryotic expression to express and purify recombinant PorB protein, four different concentrations of PorB protein, Freund's adjuvant with two genetically engineered vaccines were combined with subcutaneous immunization of mice.Results:Our study shows that the appropriate dose of the recombinant protein PorB can enhance the levels of humoral and cellular responses induced by two genetically engineered vaccines in a short period of time in mice. The PorB adjuvant group may cause statistically higher antibody titers for both genetically engineered vaccines compared to Freund's commercial adjuvant (P<0.001).Conclusion:The recombinant protein PorB may be a good candidate adjuvant for improving the protective effect of vaccines against porcine circovirus type 2 and Mycoplasma hyopneumoniae, and the protein can be used for future practical applications.

scholarly journals Post-noon two-minute period pulsating aurora and their relationship to the dayside convection pattern

1999 ◽  
Vol 17 (7) ◽  
pp. 877-891 ◽  
Author(s):  
S. E. Milan ◽  
T. K. Yeoman ◽  
M. Lester ◽  
J. Moen ◽  
P. E. Sandholt
Keyword(s):  
Current System ◽  
Wave Activity ◽  
Mhd Waves ◽  
Magnetohydrodynamic Wave ◽  
Auroral Emission ◽  
Minute Period ◽  
Optical Signature ◽  
Short Period ◽  
Auroral Emissions ◽  
Auroral Phenomena

Abstract. Poleward-moving auroral forms, as observed by meridian-scanning photometers, in the vicinity of the cusp region are generally assumed to be the optical signature of flux transfer events. Another class of quasi-continuous, short period (1-2 min) wave-like auroral emission has been identified, closely co-located with the convection reversal boundary in the post-noon sector, which is similar in appearance to such cusp aurora. It is suggested that these short period wave-like auroral emissions, the optical signature of boundary plasma sheet precipitation in the region 1 field-aligned current system, are associated with ULF magnetohydrodynamic wave activity, which is observed simultaneously by ground magnetometer stations. This association with ULF wave activity is strengthened by the observation of several harmonic frequencies in the pulsation spectrum, each an overtone of the fundamental standing wave resonance frequency.Key words. Magnetospheric physics (auroral phenomena; magnetopause · cusp · and boundary layers; MHD waves and instabilities)

Simple and Robust RSSI Estimation Using M-Estimator

2013 ◽  
Vol 756-759 ◽  
pp. 3946-3951
Author(s):  
Quan Zheng Zhu ◽  
Le Yang ◽  
Wei Li
Keyword(s):  
Moving Average ◽  
Estimation Algorithm ◽  
Signal Propagation ◽  
Network Routing ◽  
Link Quality ◽  
Superior Performance ◽  
Estimation Methods ◽  
Accurate Estimation ◽  
Practical Applications ◽  
M Estimator

Accurate estimation of the received signal strength indicator (RSSI) from a set of sequentially measured ones is essential for a number of practical applications including link quality evaluation for sensor network routing, indoor wireless localization and more recently, handover in health monitoring systems. This paper develops a simple and robust RSSI estimation algorithm that can effectively mitigate the magnitude variation in the RSSI measurements due to the combined effects of fast fading and non-line-of-sight (NLOS) signal propagation. The new method is based on the robust M-estimator and we propose a simple approach that requires bisection search only to obtain the robust RSSI estimate. Computer simulations corroborate the validity of the theoretical developments and demonstrate the superior performance of the proposed technique over commonly adopted RSSI estimation methods including the simple moving average, the discrete Kalman filter and the exponential smoothing.

scholarly journals The T phase of shallow-focus earthquakes*

1950 ◽  
Vol 40 (1) ◽  
pp. 25-51 ◽  
Author(s):  
Ivan Tolstoy ◽  
Maurice Ewing
Keyword(s):  
Dominican Republic ◽  
Velocity Of Sound ◽  
Practical Applications ◽  
Short Period ◽  
T Phase ◽  
Shallow Focus

Abstract A short-period phase, 0.5 sec. period or less, traveling through the ocean with the velocity of sound in water has been identified on a large number of seismograms of earthquakes occurring at sea. This arrival was identified on the Benioff short-period seismograms of the Weston, Fordham, and Ottawa stations for a series of Dominican Republic shocks, and on the Benioff short-period seismograms of the Pasadena network of stations and the Mount Hamilton and Mineral stations for a series of major Japanese and Aleutian shocks. The existence of this phase had been noted previously by Linehan, who was at a loss to provide an explanation for them. The mechanism of propagation of the T phase is discussed and several practical applications are described.

A Multibody Loop Constraints Approach for Modelling Cam/Follower Devices: Application in Mobile Robotics

1999 ◽  
Author(s):  
Paul Fisette ◽  
Krzysztof Lipiński ◽  
Jean-Claude Samin
Keyword(s):  
Degrees Of Freedom ◽  
Mobile Robotics ◽  
Current System ◽  
Constraint Force ◽  
Contact Phase ◽  
Practical Applications ◽  
Cam Follower ◽  
Intermittent Contact ◽  
Original Application ◽  
Multi Body

Abstract This paper proposes a formulation for modelling mechanisms with cam/follower type of contact using a multibody approach in relative coordinates. The proposed approach is inspired from the wheel/rail contact model developed in (Fisette, Samin, 1994) but in the present case, possible intermittent contact between the cam and the follower is considered, for generality purposes. Loop kinematic constraints are introduced to satisfy tangent and punctual contact as long as the bodies lean against each other. The effective presence (or not) of the contact is governed by the sign of the normal constraint force which can be computed thanks to the Lagrange multipliers technique. The above-mentioned option to kinematically constraint the bodies in their “contact phase” unavoidably leads to shift from one model to another when a contact disappears (or conversely reappears). Indeed, this increases (or decreases) the number of degrees of freedom of the current system. The control of the variable partitioning is thus absolutely necessary and is all the more complex that practical applications can contain several pairs of bodies in intermittent contact. As regards the applications, a comparison with another multi-body formalism and an experimental validation are discussed at first. Then, the modelling and simulation of universal wheels of an omnimobile mobile robot, developed in our Division, are proposed. The latter model represents a quite original application of the proposed multibody formulation. Computations are now in progress to analyse the complete behaviour of the robot, including control performances.

Acoustic impedance logs computed from seismic traces

Geophysics ◽  
1979 ◽  
Vol 44 (9) ◽  
pp. 1485-1501 ◽  
Author(s):  
M. Becquey ◽  
M. Lavergne ◽  
C. Willm
Keyword(s):  
Time Series ◽  
Acoustic Impedance ◽  
Seismic Velocity ◽  
Physical Property ◽  
Well Logs ◽  
Accurate Estimation ◽  
Low Frequencies ◽  
Short Period ◽  
And Migration ◽  
Initial Processing

Acoustic impedance, the product of seismic velocity and density, is a basic physical property of rocks. Seismic traces are converted into pseudoreflection‐coefficient time series by appropriate initial processing, then into acoustic impedance by the inversion of the time series. Such pseudologs are roughly equivalent to logs recorded in wells drilled at every seismic trace location. They yield important information concerning the nature of the rock and variations in lithology. To obtain the best quality pseudologs, careful initial processing is necessary: true‐amplitude recovery, appropriate deconvolution, common‐depth‐point (CDP) stack, wave‐shaping, wave‐equation migration, and amplitude scaling. The low frequencies from moveout velocity information are inserted. Both the short‐period information computed from reflection amplitudes and the long‐period trend computed from reflection moveout are displayed on acoustic impedance logs. Possible causes of pseudolog distortions are inaccuracies of amplitude recovery and scaling, imperfection of deconvolution and migration, and difficulties of calibrating the pseudolog to an acoustic log derived from well logs. Such calibration increases the precision; facies variations observed in well logs can be extrapoled to large distances from the wells, leading to a more accurate estimation of hydrocarbon reserves.

scholarly journals Infection Age as a Predictor of Epidemiological Metrics for Malaria

2021 ◽  
Author(s):  
John M Henry ◽  
Austin Carter ◽  
David L Smith
Keyword(s):  
Growth Phase ◽  
Time Course ◽  
Chronic Phase ◽  
Transmission Efficiency ◽  
Accurate Estimation ◽  
Rapid Decline ◽  
Strongly Correlated ◽  
Infection Age ◽  
Short Period ◽  
Age Of Infection

Abstract Background Accurate estimation of the burden of Plasmodium falciparum is essential for strategic planning for control and elimination. Due in part to the extreme heterogeneity in malaria exposure, immunity, other causes of disease, direct measurements of fever and disease attributable to malaria can be difficult. This can make a comparison of epidemiological metrics both within and between populations hard to interpret. An essential part of untangling this is an understanding of the complex time-course of malaria infections.Methods We reanalyzed malaria therapy infections in which individuals were intentionally infected with malaria parasites. In this analysis, we examined the age of an infection as a covariate describing aggregate patterns across all infections. We performed a series of piecewise linear and generalized linear regressions to highlight the infection age dependent patterns in both parasitemia and gametocytemia, and from parasitemia and gametocytemia to fever and transmission probabilities, respectively. Results The observed duration of untreated patent infection was 130 days. As infections progressed, the fraction of infections subpatent by microscopy increased steadily. The time-averaged malaria infections had three distinct phases in parasitemia: a growth phase for the first 6 days of patency, a rapid decline from day 6 to day 18, and a slowly declining chronic phase for the remaining duration of the infection. During the growth phase, parasite densities increased sharply to a peak. Densities sharply decline for a short period of time after the peak. During the chronic phase, infections declined steadily as infections age. Gametocytemia was strongly correlated with lagged asexual parasitemia. Fever rates and transmission efficiency were strongly correlated with parasitemia and gametocytemia. The comparison between raw data and prediction from the age of infection has good qualitative agreement across all quantities of interest for predicting averaged effects. Conclusion We established age of infection as a potentially useful covariate for malaria epidemiology. Infection age can be estimated given a history of exposure; accounting for exposure history may potentially provide a new way to estimate malaria-attributable fever rates, transmission efficiency, patent fraction, and more in immunologically naïve individuals such as children and people in low-transmission regions. Understanding how immune responses modify these statistical relationships is key for being able to apply these results more broadly.

scholarly journals A Survey on Identification of Blood Group Types and its Hemoglobin Estimation Using Image Processing

2021 ◽  
pp. 1034-1040
Author(s):  
Kanchan Prakash Pachghare ◽  
Dr. Sandeep V. Rode
Keyword(s):  
Blood Group ◽  
Human Blood ◽  
Current System ◽  
Short Interval ◽  
Test Procedure ◽  
Blood Groups ◽  
Blood Type ◽  
Blood Collection ◽  
Blood Typing ◽  
Short Period

It is very crucial to determine human blood groups in an emergency situation. But according to current system, the detection procedure is very slow. At present, human blood groups are determined manually through plate test procedure. It consists of blood collection and mixing with specific reagents in order to determine the blood agglutination. Blood typing is system which basically used to detect specific blood group of human. Investigation of appropriate blood type within short interval of time plays vital role in blood transfusion, donation, accident and other emergency situations. Currently, blood typing tests are performed by technicians in laboratories. But it is monotonous to do with large number of blood samples, require more time to diagnosis and, as these tests carried out manually, it may introduce human error which will be harmful. Hemoglobin (Hb), a very significant parameter for the human body and deficiency of it causes anemia. During pregnancy, menstruation and ICU deficiency of it can be very risky and even caused death. So, it is important to diagnose it continuously. Usually, physicians examine it by conducting a blood test to confirm it is painful, time-consuming and costly. The major concept of this study is to screen Hb levels within a short period of time. This paper focused on recent advances in detection of blood group with hemoglobin, which can classify different blood group within short period of time with great accuracy and calculate its hemoglobin level.

A dissipative point-vortex model for nearshore circulation

2007 ◽  
Vol 589 ◽  
pp. 455-478 ◽  
Author(s):  
E. TERRILE ◽  
M. BROCCHINI
Keyword(s):  
Vortex Dynamics ◽  
Large Scale ◽  
Current System ◽  
Single Point ◽  
Point Vortex ◽  
Breaking Wave ◽  
Rip Current ◽  
Practical Applications ◽  
Vortex Model ◽  
Point Vortex Model

The hydrodynamic circulation of a nearshore region with complex bathymetry is inves- tigated by means of a point-vortex approach similar, but more complete and suited to practical applications, to that of Kennedy (J. Fluid Mech. vol. 497, 2003, p. 225). The generation and dissipation of each single-point vortex are analysed in detail to obtain a complete description of the vortex dynamics. In particular, we clarify how the mechanism for the generation of breaking-wave-induced macrovortices (large-scale two-dimensional horizontal vortices) can be practically implemented and we discuss in detail the mechanism leading to the dissipation of the circulation assigned to each vortex. Available approximate relations for the rate of generation of bar vortices are placed in context and discussed in detail, and novel approximate relations for the shore vortex generation and for the vortex viscous dissipation are proposed, the latter largely improving the description of the point vortex dynamics. Results have been obtained using three ‘typical’ rip-current bathymetries for which we also test qualitatively and quantitatively the model comparing the vorticity dynamics with the results obtained by means of both wave-resolved and wave-averaged circulation models. A comparison of dynamically equivalent flow configurations shows that the dissipative point-vortex model solutions, neglecting any influence of the wave field, provide rip current velocities in good agreement with both types of numerical solution. A more complete description of the rip current system, not limited to the rip-neck region as given by Kennedy (2003) by mean of an inviscid model, has been achieved by including dissipative effects.

Sign in / Sign up

Export Citation Format

Share Document