scholarly journals Comparison of Four RTK Receivers Operating in the Static and Dynamic Modes Using Measurement Robotic Arm

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7794
Author(s):  
Jan Kadeřábek ◽  
Vadym Shapoval ◽  
Pavel Matějka ◽  
Milan Kroulík ◽  
František Kumhála
Keyword(s):  
Dynamic Testing ◽  
Dynamic Properties ◽  
Low Cost ◽  
Reference Method ◽  
Ground Truth ◽  
Dynamic Mode ◽  
Reference Trajectory ◽  
Static Properties ◽  
Dynamic Movement ◽  
Error Indicators

While the existing research provides a wealth of information about the static properties of RTK receivers, less is known about their dynamic properties, although it is clear that the vast majority of field operations take place when the machine is moving. A new method using a MRA for the evaluation of RTK receivers in movement with a precise circular reference trajectory (r = 3 m) was proposed. This reference method was developed with the greatest possible emphasis on the positional, time and repeatable accuracy of ground truth. Four phases of the measurement scenario (static, acceleration, uniform movement and deceleration) were used in order to compare four different types of RTK receiver horizontal operation accuracy over three measurement days. The worst result of one of the receivers was measured at SSR = 13.767% in dynamic movement. Since the same “low-cost” receiver without an INS unit had SSR = 98.14% in previous static measurements, so it can be assumed that the motion had a very significant effect on the dynamic properties of this receiver. On the other hand, the best “high-end” receiver with an INS unit had SSR = 96.938% during the dynamic testing scenarios. The median values of the deviations were always better during uniform movements than during acceleration or braking. In general, the positioning accuracy was worse in the dynamic mode than in the static one for all the receivers. Error indicators (RMSerr and Me) were found several times higher in the dynamic mode than in the static one. These facts should be considered in the future development of modern agricultural machinery and technology.

scholarly journals Quantification and Classification of Diclofenac Sodium Content in Dispersed Commercially Available Tablets by Attenuated Total Reflection Infrared Spectroscopy and Multivariate Data Analysis

2021 ◽  
Vol 14 (5) ◽  
pp. 440
Author(s):  
Eirini Siozou ◽  
Vasilios Sakkas ◽  
Nikolaos Kourkoumelis
Keyword(s):  
Infrared Spectroscopy ◽  
Low Cost ◽  
Diclofenac Sodium ◽  
Reference Method ◽  
Sodium Content ◽  
Attenuated Total Reflection ◽  
Accuracy And Precision ◽  
Significant Difference ◽  
Ft Ir

A new methodology, based on Fourier transform infrared spectroscopy equipped with an attenuated total reflectance accessory (ATR FT-IR), was developed for the determination of diclofenac sodium (DS) in dispersed commercially available tablets using chemometric tools such as partial least squares (PLS) coupled with discriminant analysis (PLS-DA). The results of PLS-DA depicted a perfect classification of the tablets into three different groups based on their DS concentrations, while the developed model with PLS had a sufficiently low root mean square error (RMSE) for the prediction of the samples’ concentration (~5%) and therefore can be practically used for any tablet with an unknown concentration of DS. Comparison with ultraviolet/visible (UV/Vis) spectrophotometry as the reference method revealed no significant difference between the two methods. The proposed methodology exhibited satisfactory results in terms of both accuracy and precision while being rapid, simple and of low cost.

Modal Analyses of Deployable Truss Structures Based on Shape Memory Polymer Composites

2016 ◽  
Vol 08 (07) ◽  
pp. 1640009 ◽  
Author(s):  
Fengfeng Li ◽  
Liwu Liu ◽  
Xin Lan ◽  
Tong Wang ◽  
Xiangyu Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Shape Memory ◽  
Polymer Composites ◽  
Dynamic Properties ◽  
Low Cost ◽  
Shape Memory Polymer ◽  
Truss Structures ◽  
Modal Test ◽  
The Stability ◽  
Mechanical Devices

With large spatial deployable antennas used more widely, the stability of deployable antennas is attracting more attention. The form of the support structure is an important factor of the antenna’s natural frequency, which is essential to study to prevent the resonance. The deployable truss structures based on shape memory polymer composites (SMPCs) have made themselves feasible for their unique properties such as highly reliable, low-cost, light weight, and self-deployment without complex mechanical devices compared with conventional deployable masts. This study offers deliverables as follows: an establishment of three-longeron beam and three-longeron truss finite element models by using ABAQUS; calculation of natural frequencies and vibration modes; parameter studies for influence on their dynamic properties; manufacture of a three-longeron truss based on SMPC, and modal test of the three-longeron truss. The results show that modal test and finite element simulation fit well.

A Proxy Flow Modelling Workflow to Estimate Gridded Dynamic Properties and Well Production Rates by Deep Learning Algorithms

2021 ◽  
Author(s):  
Soumi Chaki ◽  
Yevgeniy Zagayevskiy ◽  
Terry Wong
Keyword(s):  
Neural Network ◽  
Deep Learning ◽  
Dynamic Properties ◽  
Reservoir Management ◽  
Flow Modeling ◽  
Static Properties ◽  
Production Rates ◽  
Reservoir Properties ◽  
Well Production ◽  
Reservoir Simulator

Abstract This paper proposes a deep learning-based framework for proxy flow modeling to predict gridded dynamic petroleum reservoir properties (like pressure and saturation) and production rates for wells in a single framework. It approximates the solution of a full physics-based numerical reservoir simulator, but runs much more rapidly, allowing users to generate results for a much wider range of scenarios in a given time than could be done with a full physics simulator. The proxy can be used for reservoir management tasks like history matching, uncertainty quantification, and field development optimization. A deep-learning based methodology for accurate proxy-flow modeling is presented which combines U-Net (a variant of convolutional neural network) to predict gridded dynamic properties and deep neural network (DNN) models to forecast well production rates. First, gridded dynamic properties, such as reservoir pressure and phase saturations, are predicted from static properties like reservoir rock porosity and absolute permeability using a U-Net. Then, the static properties and the dynamic properties predicted by the U-Net are input to a DNN to predict production rates at the well perforations. The inclusion of U-net predicted pressure and saturations improves the quality of the well rate predictions. The proposed methodology is presented with the synthetic Brugge reservoir discretized into grid blocks. The U-Net input consists of three properties: dynamic gridded reservoir properties (such as pressure or fluid saturation) at the current state, static gridded porosity, and static gridded permeability. The U-Net has only one output property, the target gridded property (such as pressure or saturation) at the next time step. Training and testing datasets are generated by running 13 full physics flow simulations and dividing them in a 12:1 ratio. Nine U-Net models are calibrated to predict pressures/saturations, one for each of the nine grid layers present in the Brugge model. These outputs are then concatenated to obtain the complete pressure/saturation model for all nine layers. The constructed U-Net models match the distributions of generated pressures/saturations of the numerical reservoir simulator with a correlation coefficient value of approximately 0.99 and above 95% accuracy. The DNN models approximate well production rates accurately from U-Net predicted pressures and saturations along with static properties like transmissibility and horizontal permeability. For each well and each well perforation, the production rate is predicted with the DNN model. The use of the constructed proxy flow model generates reservoir predictions within a few minutes compared to the hours or days typically taken by a full physics flow simulator. The direct connection that is established between the gridded static and dynamic properties of the reservoir and well production rates using U-Net and DNN models has not been presented previously. Using only a small number of runs for its training, the workflow matches the numerical reservoir simulator results with reduced computational effort. This helps reservoir engineers make informed decisions more quickly, resulting in more efficient reservoir management.

scholarly journals Flow Simulation Using Local Grid Refinements to Model Laminated Reservoirs

2018 ◽  
Vol 73 ◽  
pp. 5 ◽  
Author(s):  
Manuel Gomes Correia ◽  
Célio Maschio ◽  
Denis José Schiozer
Keyword(s):  
Simulation Model ◽  
Dynamic Properties ◽  
Flow Behavior ◽  
Flow Simulation ◽  
Coarse Grid ◽  
Thin Layers ◽  
Static Properties ◽  
Dynamic Representation ◽  
Medium Flow ◽  
Local Grid

Super-giant carbonate fields, such as Ghawar, in Saudi Arabia, and Lula, at the Brazilian pre-salt, show highly heterogeneous behavior that is linked to high permeability intervals in thin layers. This article applies Local Grid Refinements (LGR) integrated with upscaling procedures to improve the representation of highly laminated reservoirs in flow simulation by preserving the static properties and dynamic trends from geological model. This work was developed in five main steps: (1) define a conventional coarse grid, (2) define LGR in the conventional coarse grid according to super-k and well locations, (3) apply an upscaling procedure for all scenarios, (4) define LGR directly in the simulation model, without integrate geological trends in LGR and (5) compare the dynamic response for all cases. To check results and compare upscaling matches, was used the benchmark model UNISIM-II-R, a refined model based on a combination of Brazilian Pre-salt and Ghawar field information. The main results show that the upscaling of geological models for coarse grid with LGR in highly permeable thin layers provides a close dynamic representation of geological characterization compared to conventional coarse grid and LGR only near-wells. Pseudo-relative permeability curves should be considered for (a) conventional coarse grid or (b) LGR scenarios under dual-medium flow simulations as the upscaling of discrete fracture networks and dual-medium flow models presents several limitations. The conventional approach of LGR directly in simulation model, presents worse results than LGR integrated with upscaling procedures as the extrapolation of dynamic properties to the coarse block mismatch the dynamic behavior from geological characterization. This work suggests further improvements for results for upscaling procedures that mask the flow behavior in highly laminated reservoirs.

Trilateration approaches for seamless out-/indoor GNSS and Wi-Fi smartphone positioning

2019 ◽  
Vol 13 (1) ◽  
pp. 47-61
Author(s):  
Guenther Retscher ◽  
Jonathan Kleine ◽  
Lisa Whitemore
Keyword(s):  
Inertial Sensors ◽  
Low Cost ◽  
Ground Truth ◽  
Mobile User ◽  
Location Based Services ◽  
Raspberry Pi ◽  
Indoor Environments ◽  
Point Location ◽  
Point Determination ◽  
The Relationship

Abstract More and more sensors and receivers are found nowadays in smartphones which can enable and improve positioning for Location-based Services and other navigation applications. Apart from inertial sensors, such as accelerometers, gyroscope and magnetometer, receivers for Wireless Fidelity (Wi-Fi) and GNSS signals can be employed for positioning of a mobile user. In this study, three trilateration methods for Wi-Fi positioning are investigated whereby the influence of the derivation of the relationship between the received signal strength (RSS) and the range to an Access Points (AP) are analyzed. The first approach is a straightforward resection for point determination and the second is based on the calculation of the center of gravity in a triangle of APs while weighting the received RSS. In the third method a differential approach is employed where as in Differential GNSS (DGNSS) corrections are derived and applied to the raw RSS measurements. In this Differential Wi-Fi (DWi-Fi) method, reference stations realized by low-cost Raspberry Pi units are used to model temporal RSS variations. In the experiments in this study two different indoor environments are used, one in a laboratory and the second in the entrance of an office building. The results of the second and third approach show position deviations from the ground truth of around 2 m in dependence of the geometrical point location. Furthermore, the transition between GNSS positioning outdoors and Wi-Fi localization indoors in the entrance area of the building is studied.

scholarly journals Synchronous fluorescence as a green and selective tool for simultaneous determination of bambuterol and its main degradation product, terbutaline

2018 ◽  
Vol 5 (10) ◽  
pp. 181359 ◽  
Author(s):  
Samah Abo El Abass ◽  
Heba Elmansi
Keyword(s):  
Degradation Product ◽  
Low Cost ◽  
Reference Method ◽  
Cost Effective ◽  
Zero Crossing ◽  
Cost Effective Method ◽  
Validation Parameters ◽  
Main Degradation Product ◽  
20 Nm

A green, sensitive and cost-effective method is introduced in this research for the determination of bambuterol and its main degradation product, terbutaline, simultaneously, relying on the synchronous spectrofluorimetric technique. First derivative synchronous spectrofluorimetric amplitude is measured at Δ λ = 20 nm, so bambuterol can be quantitated at 260 nm, and terbutaline can be measured at 290 nm, each at the zero crossing point of the other. The amplitude–concentration plots were linear over the concentration ranges of 0.2–6.0 µg ml −1 and 0.2–4.0 µg ml −1 for both bambuterol and terbutaline, respectively. Official guidelines were followed to calculate the validation parameters of the proposed method. The low values of limits of detection of 0.023, 0.056 µg ml −1 and limits of quantitation of 0.071, 0.169 µg ml −1 for bambuterol and terbutaline, respectively, point to the sensitivity of the method. Bambuterol is a prodrug for terbutaline, and the latter is considered its degradation product so the established method could be regarded as a stability-indicating one. Moreover, the proposed method was used for the analysis of bambuterol and terbutaline in their single ingredient preparations and the results revealed statistical agreement with the reference method. The suggested method, being a simple and low-cost procedure, is superior to the previously published methods which need more sophisticated techniques, longer analysis time and highly toxic solvents and reagents. It could be considered as an eco-friendly analytical procedure.

scholarly journals Randomized Projection Learning Method for Dynamic Mode Decomposition

Mathematics ◽  
2021 ◽  
Vol 9 (21) ◽  
pp. 2803
Author(s):  
Sudam Surasinghe ◽  
Erik Bollt
Keyword(s):  
Dimensional Space ◽  
Low Cost ◽  
Random Projection ◽  
Dynamic Mode Decomposition ◽  
Projection Algorithm ◽  
Dynamic Mode ◽  
Operator Matrix ◽  
Full Spectrum ◽  
Practical Applications ◽  
Mode Decomposition

A data-driven analysis method known as dynamic mode decomposition (DMD) approximates the linear Koopman operator on a projected space. In the spirit of Johnson–Lindenstrauss lemma, we will use a random projection to estimate the DMD modes in a reduced dimensional space. In practical applications, snapshots are in a high-dimensional observable space and the DMD operator matrix is massive. Hence, computing DMD with the full spectrum is expensive, so our main computational goal is to estimate the eigenvalue and eigenvectors of the DMD operator in a projected domain. We generalize the current algorithm to estimate a projected DMD operator. We focus on a powerful and simple random projection algorithm that will reduce the computational and storage costs. While, clearly, a random projection simplifies the algorithmic complexity of a detailed optimal projection, as we will show, the results can generally be excellent, nonetheless, and the quality could be understood through a well-developed theory of random projections. We will demonstrate that modes could be calculated for a low cost by the projected data with sufficient dimension.

scholarly journals PERFORMANCE ASSESSMENT OF INTEGRATED SENSOR ORIENTATION WITH A LOW-COST GNSS RECEIVER

2017 ◽  
Vol IV-2/W3 ◽  
pp. 75-80 ◽  
Author(s):  
M. Rehak ◽  
J. Skaloud
Keyword(s):  
Position Control ◽  
Low Cost ◽  
Satellite System ◽  
Bundle Adjustment ◽  
Single Frequency ◽  
Reference Trajectory ◽  
Integrated Sensor ◽  
Homogeneous Surface ◽  
Gnss Receiver ◽  
Sensor Orientation

Mapping with Micro Aerial Vehicles (MAVs whose weight does not exceed 5&amp;thinsp;kg) is gaining importance in applications such as corridor mapping, road and pipeline inspections, or mapping of large areas with homogeneous surface structure, e.g. forest or agricultural fields. In these challenging scenarios, integrated sensor orientation (ISO) improves effectiveness and accuracy. Furthermore, in block geometry configurations, this mode of operation allows mapping without ground control points (GCPs). Accurate camera positions are traditionally determined by carrier-phase GNSS (Global Navigation Satellite System) positioning. However, such mode of positioning has strong requirements on receiver’s and antenna’s performance. In this article, we present a mapping project in which we employ a single-frequency, low-cost (<&amp;thinsp;$100) GNSS receiver on a MAV. The performance of the low-cost receiver is assessed by comparing its trajectory with a reference trajectory obtained by a survey-grade, multi-frequency GNSS receiver. In addition, the camera positions derived from these two trajectories are used as observations in bundle adjustment (BA) projects and mapping accuracy is evaluated at check points (ChP). Several BA scenarios are considered with absolute and relative aerial position control. Additionally, the presented experiments show the possibility of BA to determine a camera-antenna spatial offset, so-called lever-arm.

TSLAM: Tethered simultaneous localization and mapping for mobile robots

2017 ◽  
Vol 36 (12) ◽  
pp. 1363-1386 ◽  
Author(s):  
Patrick McGarey ◽  
Kirk MacTavish ◽  
François Pomerleau ◽  
Timothy D Barfoot
Keyword(s):  
Mobile Robots ◽  
Particle Filter ◽  
Low Cost ◽  
Simultaneous Localization And Mapping ◽  
Ground Truth ◽  
Anchor Point ◽  
Outlier Rejection ◽  
Cluttered Environments ◽  
Localization And Mapping ◽  
Anchor Points

Tethered mobile robots are useful for exploration in steep, rugged, and dangerous terrain. A tether can provide a robot with robust communications, power, and mechanical support, but also constrains motion. In cluttered environments, the tether will wrap around a number of intermediate ‘anchor points’, complicating navigation. We show that by measuring the length of tether deployed and the bearing to the most recent anchor point, we can formulate a tethered simultaneous localization and mapping (TSLAM) problem that allows us to estimate the pose of the robot and the positions of the anchor points, using only low-cost, nonvisual sensors. This information is used by the robot to safely return along an outgoing trajectory while avoiding tether entanglement. We are motivated by TSLAM as a building block to aid conventional, camera, and laser-based approaches to simultaneous localization and mapping (SLAM), which tend to fail in dark and or dusty environments. Unlike conventional range-bearing SLAM, the TSLAM problem must account for the fact that the tether-length measurements are a function of the robot’s pose and all the intermediate anchor-point positions. While this fact has implications on the sparsity that can be exploited in our method, we show that a solution to the TSLAM problem can still be found and formulate two approaches: (i) an online particle filter based on FastSLAM and (ii) an efficient, offline batch solution. We demonstrate that either method outperforms odometry alone, both in simulation and in experiments using our TReX (Tethered Robotic eXplorer) mobile robot operating in flat-indoor and steep-outdoor environments. For the indoor experiment, we compare each method using the same dataset with ground truth, showing that batch TSLAM outperforms particle-filter TSLAM in localization and mapping accuracy, owing to superior anchor-point detection, data association, and outlier rejection.

Mechanical Behaviour of Beta Titanium Alloys

2021 ◽  
Vol 1016 ◽  
pp. 964-970
Author(s):  
Nageswara Rao ◽  
Geetha Manivasagam
Keyword(s):  
Heat Treatment ◽  
Titanium Alloys ◽  
Dynamic Properties ◽  
Solution Treatment ◽  
Weight Ratio ◽  
High Strength ◽  
Static Properties ◽  
Beta Titanium Alloy ◽  
Beta Titanium ◽  
Beta Titanium Alloys

Beta titanium alloys have several attractive features; this has resulted in this group of alloys receiving much attention since 1980’s. Among the attributes which distinguish them for their superiority over other structural materials are (i) high strength to which they can be heat treated, resulting in high strength to weight ratio (ii) high degree of hardenability which enables heat treatment in large section sizes to high strength levels (iii) excellent hot and cold workability, making them as competitive sheet materials etc. The standard heat treatment consists of solution treatment in beta or alpha plus beta phase field followed by aging. However, certain aging treatments can render the materials in a state of little or no ductility; the designer has to be aware of this behaviour and has to keep away from such treatments while working with the materials. Such unfavourable aging treatments may adversely affect not only the static properties such as reduction in area and elongation in a tensile test, but also dynamic properties such as impact toughness. Results of fractographic studies are in line with those of mechanical testing. The authors would present the foregoing analysis, based primarily on the wide-ranging researches they carried out on beta titanium alloy Ti15-3 and to some extent data published by researchers on other grades of beta titanium alloys. An attempt is made to explain the mechanisms underlying the embrittlement reactions that take place in beta titanium alloys under non-optimal aging treatments.

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