On optimization of geodetic reference networks of accelerators using laser trackers

2017 ◽  
Vol 923 (5) ◽  
pp. 2-6
Author(s):  
P.P. Murzincev ◽  
А.V. Polianskiy ◽  
L.E. Serdakov

The features of laser tracker measurements and their accounting for designing geodetic networks on the accelerator complexes are considered. The key parameters for the optimization of the spatial geodetic network of the accelerator are proposed. The dependence of average mean square errors on the radial and altitudinal directions of orientation of the sighting beam for distances from 1 to 30 meters was defined. The influence of the choice of stations for mounting the laser tracker to determine the parameters of the ellipsoid of errors was studied. The measurements for three variants of geodetic networks in the tunnel with the adopted geometric parameters were simulated. The data of the deviations of the points of the network radius, altitude relative to the project was indicated. The obtained results can be useful both at the design stage of geodetic network accelerator, and at the stage of installation of technological equipment.

2019 ◽  
Vol 953 (11) ◽  
pp. 22-25
Author(s):  
L.E. Serdakov ◽  
P.P. Murzincev ◽  
D.B. Burenkov ◽  
А.V. Polianskiy

A review article on the alignment of technological equipment located on a closed ring path (for example cyclic accelerators). Such geodesic works are very difficult, since the tolerance for alignment in the radial and altitude directions is 0,05 mm. The main survey instrument in such works is a laser tracker. The positions of the laser tracker stations were studied during equipment alignment, taking into account the effect of errors in the transverse directions. The values of the mean square errors for the distances and angles of the API trackers are used. Calculations are made for distances from 0,5 to 10 meters usual for production of precision measurements. The cases of installation of a laser tracker outside and inside the project radius are considered. The results of error calculations when changing the vertical angle of the laser tracker are also presented. The obtained results enable determining the 3D zones for the alignment process equipment, which will improve the efficiency of geodetic works.


1974 ◽  
Vol 29 (6) ◽  
pp. 901-904 ◽  
Author(s):  
O. Oberhammer ◽  
O. Glemser ◽  
H. Klüver

The molecular structure of ClNSOF2 was determined by electron diffraction of gases. The following geometric parameters were obtained:Cl-N=1.715(5), S=N=1.484(7), S=O=1.394(3), S-F=1.548(3) Å, ∢ ClNS=114.7 (8), ∢ FSF=92.6(.8), ∢ NSF=111.8(.9) ∢ NSO=117.4 (3.1) and ∢ OSF=108.6 (.8)°. The results for the mean square amplitudes of vibration are given in the paper and an attempt is made to explain differences in corresponding parameters of some related molecules.


Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 885
Author(s):  
Sergio Ghidini ◽  
Luca Maria Chiesa ◽  
Sara Panseri ◽  
Maria Olga Varrà ◽  
Adriana Ianieri ◽  
...  

The present study was designed to investigate whether near infrared (NIR) spectroscopy with minimal sample processing could be a suitable technique to rapidly measure histamine levels in raw and processed tuna fish. Calibration models based on orthogonal partial least square regression (OPLSR) were built to predict histamine in the range 10–1000 mg kg−1 using the 1000–2500 nm NIR spectra of artificially-contaminated fish. The two models were then validated using a new set of naturally contaminated samples in which histamine content was determined by conventional high-performance liquid chromatography (HPLC) analysis. As for calibration results, coefficient of determination (r2) > 0.98, root mean square of estimation (RMSEE) ≤ 5 mg kg−1 and root mean square of cross-validation (RMSECV) ≤ 6 mg kg−1 were achieved. Both models were optimal also in the validation stage, showing r2 values > 0.97, root mean square errors of prediction (RMSEP) ≤ 10 mg kg−1 and relative range error (RER) ≥ 25, with better results showed by the model for processed fish. The promising results achieved suggest NIR spectroscopy as an implemental analytical solution in fish industries and markets to effectively determine histamine amounts.


2021 ◽  
pp. 1-14
Author(s):  
Noura Hamze ◽  
Lukas Nocker ◽  
Nikolaus Rauch ◽  
Markus Walzthöni ◽  
Matthias Harders ◽  
...  

BACKGROUND: Accurate segmentation of connective soft tissues in medical images is very challenging, hampering the generation of geometric models for bio-mechanical computations. Alternatively, one could predict ligament insertion sites and then approximate the shapes, based on anatomical knowledge and morphological studies. OBJECTIVE: In this work, we describe an integrated framework for automatic modelling of human musculoskeletal ligaments. METHOD: We combine statistical shape modelling with geometric algorithms to automatically identify insertion sites, based on which geometric surface/volume meshes are created. As clinical use case, the framework has been applied to generate models of the forearm interosseous membrane. Ligament insertion sites in the statistical model were defined according to anatomical predictions following a published approach. RESULTS: For evaluation we compared the generated sites, as well as the ligament shapes, to data obtained from a cadaveric study, involving five forearms with 15 ligaments. Our framework permitted the creation of models approximating ligaments’ shapes with good fidelity. However, we found that the statistical model trained with the state-of-the-art prediction of the insertion sites was not always reliable. Average mean square errors as well as Hausdorff distances of the meshes could increase by an order of magnitude, as compared to employing known insertion locations of the cadaveric study. Using those, an average mean square error of 0.59 mm and an average Hausdorff distance of less than 7 mm resulted, for all ligaments. CONCLUSIONS: The presented approach for automatic generation of ligament shapes from insertion points appears to be feasible but the detection of the insertion sites with a SSM is too inaccurate, thus making a patient-specific approach necessary.


Author(s):  
Pavle Šćepanović ◽  
Frederik A. Döring

AbstractFor a broad range of applications, flight mechanics simulator models have to accurately predict the aircraft dynamics. However, the development and improvement of such models is a difficult and time consuming process. This is especially true for helicopters. In this paper, two rapidly applicable and implementable methods to derive linear input filters that improve the simulator model are presented. The first method is based on model inversion, the second on feedback control. Both methods are evaluated in the time domain, compared to recorded helicopter flight test data, and assessed based on root mean square errors and the Qualification Test Guide bounds. The best results were achieved when using the first method.


1944 ◽  
Vol 7 (53) ◽  
pp. 279-294
Author(s):  
G. H. Menzies

2017 ◽  
Vol 2017 ◽  
pp. 1-12
Author(s):  
Lin Lin ◽  
Fang Wang ◽  
Shisheng Zhong

Prediction technology for aeroengine performance is significantly important in operational maintenance and safety engineering. In the prediction of engine performance, to address overfitting and underfitting problems with the approximation modeling technique, we derived a generalized approximation model that could be used to adjust fitting precision. Approximation precision was combined with fitting sensitivity to allow the model to obtain excellent fitting accuracy and generalization performance. Taking the Grey model (GM) as an example, we discussed the modeling approach of the novel GM based on fitting sensitivity, analyzed the setting methods and optimization range of model parameters, and solved the model by using a genetic algorithm. By investigating the effect of every model parameter on the prediction precision in experiments, we summarized the change regularities of the root-mean-square errors (RMSEs) varying with the model parameters in novel GM. Also, by analyzing the novel ANN and ANN with Bayesian regularization, it is concluded that the generalized approximation model based on fitting sensitivity can achieve a reasonable fitting degree and generalization ability.


2017 ◽  
Vol 10 (1) ◽  
pp. 155-165 ◽  
Author(s):  
Wengang Zhang ◽  
Guirong Xu ◽  
Yuanyuan Liu ◽  
Guopao Yan ◽  
Dejun Li ◽  
...  

Abstract. This paper is to investigate the uncertainties of microwave radiometer (MWR) retrievals in snow conditions and also explore the discrepancies of MWR retrievals in zenith and off-zenith observations. The MWR retrievals were averaged in a ±15 min period centered at sounding times of 00:00 and 12:00 UTC and compared with radiosonde observations (RAOBs). In general, the MWR retrievals have a better correlation with RAOB profiles in off-zenith observations than in zenith observations, and the biases (MWR observations minus RAOBs) and root mean square errors (RMSEs) between MWR and RAOB are also clearly reduced in off-zenith observations. The biases of temperature, relative humidity, and vapor density decrease from 4.6 K, 9 %, and 1.43 g m−3 in zenith observations to −0.6 K, −2 %, and 0.10 g m−3 in off-zenith observations, respectively. The discrepancies between MWR retrievals and RAOB profiles by altitude present the same situation. Cases studies show that the impact of snow on accuracies of MWR retrievals is more serious in heavy snowfall than in light snowfall, but off-zenith observation can mitigate the impact of snowfall. The MWR measurements become less accurate in snowfall mainly due to the retrieval algorithm, which does not consider the effect of snow, and the accumulated snow on the top of the radome increases the signal noise of MWR measurements. As the snowfall drops away by gravity on the sides of the radome, the off-zenith observations are more representative of the atmospheric conditions for RAOBs.


2021 ◽  
Vol 41 (I) ◽  
pp. 55-60
Author(s):  
I. TREVOHO ◽  
◽  
A. DRBAL ◽  
E. ILKIV ◽  
M. GALYARNYK ◽  
...  

The aim is to clarify the etymology of the terms “wall leveling mark” and “wall leveling benchmark” in the context of the historical sequence of the appearance of leveling networks in the Ukrainian lands to present the author’s view on these definitions in scientific reference and encyclopedic geodetic literature. To conduct a chronological study of the phenomenon of leveling wall signs of different structures and the corresponding technologies of binding to them in leveling networks, which were created in the Ukrainian lands during the XIX–XXI centuries. Pay attention to the fact that level marks and wall frames, which are valid (working) independent geodetic signs in leveling networks, due to long-term operation are carriers of important geodetic information. Method. To study the results of the analysis of historical sources, standards, reference, encyclopedic and scientific literature in the context of the analysis of the definitions of “level mark” and “wall benchmark” was used analysis of patterns of functioning of the relevant geodetic terminological units. Results. On the territory of Ukraine during the XIX–XXI centuries. Created a leveling (height) network [State Geodetic Network, experimental operation], which operates to this day. The functioning of the leveling (height) network is regulated by legislative acts and regulations. Thanks to the geo-portal of the DGM of Ukraine created by NDIGK, it is possible to obtain information about the preserved level signs. The peculiarity of the leveling (height) network is that it was created by different departments of different countries [Glushkov V.V., 2003] with different height systems and taking into account the access of Ukrainian lands to the Black Sea. All this led to the use of different designs of wall leveling signs and, accordingly, their interpretation, which is not sufficiently reflected in the geodetic reference and regulatory literature. Scientific novelty. The performed comprehensive analysis of information sources can serve as a basis for development of scientific and technical recommendations formonitoring of level signs ofDGMofUkraine and will allow to reveal weaknesses of their functioning which are caused by changes in vital activity of the city environment. The practical value of the work is to solve the problem of distinguishing the production characteristics of the wall leveling mark and wall leveling benchmark, which are fixed leveling signs in geodetic networks of thickening and leveling networks to develop technical developments for inspection and updating points II, leveling networks classes and geodetic networks of thickening in the context of monitoring of geodetic points of DGM of Ukraine and their corresponding representation in the scientific and reference geodetic literature.


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