Estimating Nitrogen Sufficiency Index using a Natural Local Reference approach

2013 ◽  
Author(s):  
Yacine Bouroubi ◽  
Nicolas Tremblay ◽  
Philippe Vigneault ◽  
Carl Belec ◽  
Viacheslav Adamchuk
Keyword(s):  
Local Reference

scholarly journals The role of a local reference in stereoscopic detection of depth relief

2004 ◽  
Vol 44 (4) ◽  
pp. 367-376 ◽  
Author(s):  
Yury Petrov ◽  
Andrew Glennerster
Keyword(s):  
Local Reference

scholarly journals Arbitrary-order intrinsic virtual element method for elliptic equations on surfaces

CALCOLO ◽  
2021 ◽  
Vol 58 (3) ◽  
Author(s):  
Elena Bachini ◽  
Gianmarco Manzini ◽  
Mario Putti
Keyword(s):  
Arbitrary Order ◽  
Surface Geometry ◽  
Virtual Element Method ◽  
Anisotropic Character ◽  
Local Reference System ◽  
Local Reference ◽  
Local Parametrization ◽  
Manufactured Solution ◽  
Virtual Element ◽  
Element Method

AbstractWe develop a geometrically intrinsic formulation of the arbitrary-order Virtual Element Method (VEM) on polygonal cells for the numerical solution of elliptic surface partial differential equations (PDEs). The PDE is first written in covariant form using an appropriate local reference system. The knowledge of the local parametrization allows us to consider the two-dimensional VEM scheme, without any explicit approximation of the surface geometry. The theoretical properties of the classical VEM are extended to our framework by taking into consideration the highly anisotropic character of the final discretization. These properties are extensively tested on triangular and polygonal meshes using a manufactured solution. The limitations of the scheme are verified as functions of the regularity of the surface and its approximation.

Anti-IH Related Hemolytic Reaction in a Sickle Cell Patient and Further Management While Avoiding Transfusion

2020 ◽  
Vol 154 (Supplement_1) ◽  
pp. S165-S166
Author(s):  
N Yurtsever ◽  
K Wilson-Sandberg ◽  
J Dikeman ◽  
J Louie ◽  
K Fomani
Keyword(s):  
Sickle Cell ◽  
Clinical Symptoms ◽  
Acute Chest Syndrome ◽  
Reference Laboratory ◽  
Cold Temperatures ◽  
Donor Cells ◽  
Thermal Amplitude ◽  
Local Reference ◽  
Hemolytic Transfusion Reaction ◽  
Group B

Abstract Introduction/Objective H antigen is a precursor for A and B antigens and is mostly converted except for the O blood group, which has the highest amount of H antigen. I is present on all adult RBCs. Anti-IH is usually an IgM antibody active at cold temperatures, and rarely demonstrates a wide thermal amplitude and can cause a significant hemolytic transfusion reaction. Methods Data was collected from patient information and transfusion management systems. Results 38 year old female with sickle cell disease presented to the emergency room with dizziness, tachypnea and Hgb: 5.9 g/dl Hct:19.1%. Upon further review, patient chart showed that she had received an emergency RBC exchange transfusion 21 days prior to this admission for acute chest syndrome. She was B positive. The units for RBC exchange consisted of 5 group B and 1 group O units and an additional 1 group O unit later. All RBC units were matched for her phenotype; Rh, K, Duffy & Kidd, except anti-S which was ruled out. At the time of discharge, Hgb was 9.3 g/dl and Hct was 27.7%. The drop in Hgb between discharge and the present admission prompted a suspicion for delayed hemolytic reaction/hyperhemolysis. The sample sent to the local Reference Laboratory came back as follows: DAT/Coombs Positive, DAT C3 positive; positive for cold auto-anti-IH antibody. A thermal amplitude test indicated that the anti-IH was reactive at 30 C and therefore had the potential to be of clinical significance. Her Hgb continued to drop and 3 days later Hb=3.7 g/dl with instructions not to transfuse unless clinically emergent. With treatment of IVIG and steroids, reducing further blood draws and monitoring the patient for clinical symptoms only, her Hgb/Hct started to rise and the patient was discharged 4 days later with Hgb: 6.4 g/dl, and no symptoms of anemia. Conclusion Our case study is important in two ways: Firstly, it raises awareness of the severity of a cold autoantibody, i.e. anti-IH, with a wide thermal amplitude. Specifically, in this case, our attempt to provide phenotypically similar RBCs resulted in the destruction of all the type O donor cells as well as some of the B donor cells. Secondly, even with Hgb counts as low as 3.7, treating the patient and not the number proved to be better clinical practice. In conclusion, a good monitoring protocol for sickle cell patients is required to transfuse less and avoid serious complications.

scholarly journals CLASSIFICATION OF PHOTOGRAMMETRIC POINT CLOUDS OF SCAFFOLDS FOR CONSTRUCTION SITE MONITORING USING SUBSPACE CLUSTERING AND PCA

2016 ◽  
Vol XLI-B3 ◽  
pp. 725-732 ◽  
Author(s):  
Y. Xu ◽  
S. Tuttas ◽  
L. Heogner ◽  
U. Stilla
Keyword(s):  
Classification Accuracy ◽  
Subspace Clustering ◽  
Point Clouds ◽  
Automatic Monitoring ◽  
Normal Vector ◽  
Construction Site ◽  
Building Information ◽  
Local Reference ◽  
Real Scenario

This paper presents an approach for the classification of photogrammetric point clouds of scaffolding components in a construction site, aiming at making a preparation for the automatic monitoring of construction site by reconstructing an as-built Building Information Model (as-built BIM). The points belonging to tubes and toeboards of scaffolds will be distinguished via subspace clustering process and principal components analysis (PCA) algorithm. The overall workflow includes four essential processing steps. Initially, the spherical support region of each point is selected. In the second step, the normalized cut algorithm based on spectral clustering theory is introduced for the subspace clustering, so as to select suitable subspace clusters of points and avoid outliers. Then, in the third step, the feature of each point is calculated by measuring distances between points and the plane of local reference frame defined by PCA in cluster. Finally, the types of points are distinguished and labelled through a supervised classification method, with random forest algorithm used. The effectiveness and applicability of the proposed steps are investigated in both simulated test data and real scenario. The results obtained by the two experiments reveal that the proposed approaches are qualified to the classification of points belonging to linear shape objects having different shapes of sections. For the tests using synthetic point cloud, the classification accuracy can reach 80%, with the condition contaminated by noise and outliers. For the application in real scenario, our method can also achieve a classification accuracy of better than 63%, without using any information about the normal vector of local surface.

scholarly journals IMAGE-BASED ORIENTATION DETERMINATION OF MOBILE SENSOR PLATFORMS

2021 ◽  
Vol XLIII-B1-2021 ◽  
pp. 215-220
Author(s):  
O. Hasler ◽  
S. Nebiker
Keyword(s):  
Sensor Fusion ◽  
Pose Estimation ◽  
Reference System ◽  
Laser Scanner ◽  
Relative Orientation ◽  
Robotic Platform ◽  
Sensor Platforms ◽  
Local Reference ◽  
The Absolute ◽  
Additional Approach

Abstract. Estimating the pose of a mobile robotic platform is a challenging task, especially when the pose needs to be estimated in a global or local reference frame and when the estimation has to be performed while the platform is moving. While the position of a platform can be measured directly via modern tachymetry or with the help of a global positioning service GNSS, the absolute platform orientation is harder to derive. Most often, only the relative orientation is estimated with the help of a sensor mounted on the robotic platform such as an IMU, with one or multiple cameras, with a laser scanner or with a combination of any of those. Then, a sensor fusion of the relative orientation and the absolute position is performed. In this work, an additional approach is presented: first, an image-based relative pose estimation with frames from a panoramic camera using a state-of-the-art visual odometry implementation is performed. Secondly, the position of the platform in a reference system is estimated using motorized tachymetry. Lastly, the absolute orientation is calculated using a visual marker, which is placed in the space, where the robotic platform is moving. The marker can be detected in the camera frame and since the position of this marker is known in the reference system, the absolute pose can be estimated. To improve the absolute pose estimation, a sensor fusion is conducted. Results with a Lego model train as a mobile platform show, that the trajectory of the absolute pose calculated independently with four different markers have a deviation < 0.66 degrees 50% of the time and that the average difference is < 1.17 degrees. The implementation is based on the popular Robotic Operating System ROS.

scholarly journals GPS derived ground motions (2005–2014) within the Gulf of Mexico region referred to a stable Gulf of Mexico reference frame

2015 ◽  
Vol 3 (11) ◽  
pp. 6651-6688
Author(s):  
J. Yu ◽  
G. Wang
Keyword(s):  
Gulf Of Mexico ◽  
Reference Frame ◽  
Mexico City ◽  
Ground Motions ◽  
Local Reference Frame ◽  
Local Reference ◽  
Houston Area ◽  
Gps Observations ◽  
Southeastern Louisiana

Abstract. This study investigates current ground motions derived from the GPS geodesy infrastructure in the Gulf of Mexico region. The positions and velocity vectors of 161 continuous GPS (CGPS) stations are presented with respect to a newly established local reference frame, the Stable Gulf of Mexico Reference Frame (SGOMRF). Thirteen long-term (> 5 years) CGPS are used to realize the local reference frame. The root-mean-square (RMS) of the velocities of the 13 SGOMRF reference stations achieves 0.2 mm yr−1 in the horizontal and 0.3 mm yr−1 in the vertical directions. GPS observations presented in this study indicate significant land subsidence in the coastal area of southeastern Louisiana, the greater Houston metropolitan area, and two cities in Mexico (Aguascalientes and Mexico City). The most rapid subsidence is recorded at the Mexico City International airport, which is up to 26.6 cm yr−1 (2008–2014). Significant spatial variation of subsidence rates is observed in both Mexico City and the Houston area. The overall subsidence rate in the Houston area is decreasing. GPS observations in southeastern Louisiana indicate minor (4.0–6.0 mm yr−1) but consistent subsidence over time and space. This poses a potential threat to the safety of costal infrastructure in the long-term.

scholarly journals CENTIMETER-LEVEL, ROBUST GNSS-AIDED INERTIAL POST-PROCESSING FOR MOBILE MAPPING WITHOUT LOCAL REFERENCE STATIONS

2016 ◽  
Vol XLI-B3 ◽  
pp. 819-826
Author(s):  
J. J. Hutton ◽  
N. Gopaul ◽  
X. Zhang ◽  
J. Wang ◽  
V. Menon ◽  
...  
Keyword(s):  
Inertial Sensors ◽  
Global Navigation Satellite Systems ◽  
Reference Station ◽  
Mobile Mapping ◽  
Satellite Systems ◽  
Local Reference ◽  
Set Up ◽  
Global Navigation Satellite ◽  
Airborne Mapping ◽  
Advanced Model

For almost two decades mobile mapping systems have done their georeferencing using Global Navigation Satellite Systems (GNSS) to measure position and inertial sensors to measure orientation. In order to achieve cm level position accuracy, a technique referred to as post-processed carrier phase differential GNSS (DGNSS) is used. For this technique to be effective the maximum distance to a single Reference Station should be no more than 20 km, and when using a network of Reference Stations the distance to the nearest station should no more than about 70 km. This need to set up local Reference Stations limits productivity and increases costs, especially when mapping large areas or long linear features such as roads or pipelines. <br><br> An alternative technique to DGNSS for high-accuracy positioning from GNSS is the so-called Precise Point Positioning or PPP method. In this case instead of differencing the rover observables with the Reference Station observables to cancel out common errors, an advanced model for every aspect of the GNSS error chain is developed and parameterized to within an accuracy of a few cm. The Trimble Centerpoint RTX positioning solution combines the methodology of PPP with advanced ambiguity resolution technology to produce cm level accuracies without the need for local reference stations. It achieves this through a global deployment of highly redundant monitoring stations that are connected through the internet and are used to determine the precise satellite data with maximum accuracy, robustness, continuity and reliability, along with advance algorithms and receiver and antenna calibrations. <br><br> This paper presents a new post-processed realization of the Trimble Centerpoint RTX technology integrated into the Applanix POSPac MMS GNSS-Aided Inertial software for mobile mapping. Real-world results from over 100 airborne flights evaluated against a DGNSS network reference are presented which show that the post-processed Centerpoint RTX solution agrees with the DGNSS solution to better than 2.9 cm RMSE Horizontal and 5.5 cm RMSE Vertical. Such accuracies are sufficient to meet the requirements for a majority of airborne mapping applications.

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