Application of Computations with Calculation Error Exclusion for Computation Geometry Algorithms

2009 ◽  
Author(s):  
Dmitry Orlov
Keyword(s):  
Calculation Error ◽  
Computation Geometry

scholarly journals Improvement Dependability of Offshore Horizontal-Axis Wind Turbines by Applying New Mathematical Methods for Calculation the Excess Speed in Case of Wind Gusts

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3085
Author(s):  
Konstantin Osintsev ◽  
Seregei Aliukov ◽  
Alexander Shishkov
Keyword(s):  
Computer Simulation ◽  
Wind Turbines ◽  
Experimental Studies ◽  
Offshore Wind ◽  
Approximation Schemes ◽  
Calculation Error ◽  
Strong Wind ◽  
Mathematical Methods ◽  
Wind Gusts ◽  
Gas Dynamic

The problem of increasing the reliability of wind turbines exists in the development of new offshore oil and natural gas fields. Reducing emergency situations is necessary due to the autonomous operation of drilling rigs and bulk seaports in the subarctic and Arctic climate. The relevance of the topic is linked with the development of a methodology for theoretical and practical studies of gas dynamics when gas flows in a pipe, based on a mathematical model using new mathematical methods for calculation of excess speeds in case of wind gusts. Problems in the operation of offshore wind turbines arise with storm gusts of wind, which is comparable to the wave movement of the gas flow. Thus, the scientific problem of increasing the reliability of wind turbines in conditions of strong wind gusts is solved. The authors indicate a gross error in the calculations when approximating through the use of the Fourier series. The obtained results will allow us to solve one of the essential problems of modeling at this stage of its development, namely: to reduce the calculation time and the adequacy of the model built for similar installations and devices. Experimental studies of gas-dynamic flows are carried out on the example of a physical model of a wind turbine. In addition, a computer simulation of the gas-dynamic flow process was carried out. The use of new approximation schemes in processing the results of experiments and computer simulation can reduce the calculation error by 1.2 percent.

scholarly journals Analysis of Tunnel Water Inrush Considering the Influence of Surrounding Rock Permeability Coefficient by Excavation Disturbance and Ground Stress

2021 ◽  
Vol 11 (8) ◽  
pp. 3645
Author(s):  
Helin Fu ◽  
Pengtao An ◽  
Long Chen ◽  
Guowen Cheng ◽  
Jie Li ◽  
...  
Keyword(s):  
Permeability Coefficient ◽  
Water Pressure ◽  
Water Inrush ◽  
Surrounding Rock ◽  
Water Inflow ◽  
Calculation Error ◽  
External Water Pressure ◽  
Ground Stress ◽  
External Water ◽  
Inflow Prediction

Affected by the coupling of excavation disturbance and ground stress, the heterogeneity of surrounding rock is very common. Presently, treating the permeability coefficient as a fixed value will reduce the prediction accuracy of the water inflow and the external water pressure of the structure, leading to distortion of the prediction results. Aiming at this problem, this paper calculates and analyzes tunnel water inflow when considering the heterogeneity of permeability coefficient of surrounding rock using a theoretical analysis method, and compares with field data, and verifies the rationality of the formula. The research shows that, when the influence of excavation disturbance and ground stress on the permeability coefficient of surrounding rock is ignored, the calculated value of the external water force of the tunnel structure is too small, and the durability and stability of the tunnel are reduced, which is detrimental to the safety of the structure. Considering the heterogeneity of surrounding rock, the calculation error of water inflow can be reduced from 27.3% to 13.2%, which improves the accuracy of water inflow prediction to a certain extent.

Calculation Error Analysis on the Strain Fatigue Life Predication Formula of Manson-Coffinn and Damage Stain Model

2011 ◽  
Vol 197-198 ◽  
pp. 1599-1603
Author(s):  
Zhen Wei Wang ◽  
Ping An Du ◽  
Ya Ting Yu
Keyword(s):  
Fatigue Life ◽  
Error Analysis ◽  
Fatigue Failure ◽  
High Speed ◽  
Production Cost ◽  
Calculation Error ◽  
Mechanical Components ◽  
Strain Model ◽  
Engine Crankshaft

Mechanical components are subjected heavy alternate load in industries, such as engine crankshaft, wheel axle, etc. The fatigue failure happens after a long work loading, which affects the production cost, safe and time. So the fatigue life predication is fundamental for the mechanical components design. Especially, it is very important for heavy, high-speed machinery. In this paper, both main fatigue life predication formulas are introduced briefly, including Manson-Coffinn formula and Damage strain model. Then, shortages of above life predication formulas are pointed out, and coefficients are explained in detail. Further calculation error analysis is conducted on the basis of experiments on 16 materials. Results show that above life predication formulas lack calculation accuracy. Finally, it is pointed out that coefficients of fatigue life predication formulas are dependent of material performance. So it is unreliable that coefficients are constants for Manson-Coffin and Damage strain model.

scholarly journals Implementasi System Persediaan dengan Metode Grafik dan Penerapan Last In First Out pada Hasanah Collection

2019 ◽  
Vol 9 (2) ◽  
pp. 25-30
Author(s):  
Irzal Arief Wisky
Keyword(s):  
Inventory System ◽  
Calculation Error ◽  
The World ◽  
Computerized System

The purpose of this research is to produce applications that can provide information about inventory, because this is very important in the world of organizations engaged in marketing and selling goods. So from that the authors conducted research on hasanah collection, implementation is applied to determine improving the ability of the inventory system in scheduling and selling processes. For this reason, a computerized system  was built so as to minimize the calculation error to determine the amount of ending inventory in hasanah collection.

Harmonic Analysis of Non-Sinusoidal Harmonic Signals in Electric Power System

2014 ◽  
Vol 1070-1072 ◽  
pp. 779-784
Author(s):  
Dan Luo ◽  
Yi Xiao ◽  
Jie Na Zhou
Keyword(s):  
Power System ◽  
Harmonic Analysis ◽  
Short Range ◽  
Time Windows ◽  
Electric Power System ◽  
Normal Operation ◽  
Calculation Error ◽  
Interpolation Algorithm ◽  
Harmonic Signals ◽  
And Control

Harmonic Analysis and control is very important for the power system because harmonics have serious harm to its normal operation. Harmonic Analysis uses fast Fourier transform (FFT) to solve this problem though it causes the spectrum leakage which Increases the calculation error. To solve this problem, the interpolation algorithm combine with tapered time windows are used. The tapered time windows solve the long-range leakage and the interpolation algorithm solves the problem of short-range leakage.

Analysis and numerical solution of dynamic Jiles–Atherton model applied to hysteresis modeling for giant magnetostrictive materials

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ce Rong ◽  
Zhongbo He ◽  
Guangming Xue ◽  
Guoping Liu ◽  
Bowen Dai ◽  
...  
Keyword(s):  
Numerical Solution ◽  
Numerical Computation ◽  
Model Parameters ◽  
Calculation Error ◽  
Rational Form ◽  
Modified Model ◽  
Content Type ◽  
Magnetostrictive Materials ◽  
Giant Magnetostrictive Materials ◽  
Computation Scheme

PurposeOwing to the excellent performance, giant magnetostrictive materials (GMMs) are widely used in many engineering fields. The dynamic Jiles–Atherton (J-A) model, derived from physical mechanism, is often used to describe the hysteresis characteristics of GMM. However, this model, despite cited by many different literature studies, seems not to possess unique expressions, which may cause great trouble to the subsequent application. This paper aims to provide the rational expressions of the dynamic J-A model and propose a numerical computation scheme to obtain the model results with high accuracy and fast speed.Design/methodology/approachThis paper analyzes different published papers and provides a reasonable form of the dynamic J-A model based on functional properties and physical explanations. Then, a numerical computation scheme, combining the Newton method and the explicit Adams method, is designed to solve the modified model. In addition, the error source and transmission path of the numerical solution are investigated, and the influence of model parameters on the calculation error is explored. Finally, some attempts are made to study the influence of numerical scheme parameters on the accuracy and time of the computation process. Subsequently, an optimization procedure is proposed.FindingsA rational form of the dynamic J-A model is concluded in this paper. Using the proposed numerical calculation scheme, the maximum calculation error, while computing the modified model, can remain below 2 A/m under different model parameter combinations, and the computation time is always less than 0.5 s. After optimization, the calculation speed can be enhanced with the computation accuracy guaranteed.Originality/valueTo the best of the authors’ knowledge, this paper is the first one trying to provide a rational form of the dynamic J-A model among different citations. No other research studies focus on designing a detailed computation scheme targeting the fast and accurate calculation of this model as well. And the performance of the proposed calculation method is validated in different conditions.

scholarly journals Approximate Inertial Coordinate System Selections for Rotation Problems - The Gravitational Field of the Celestial Body Higher than the Object Being Rotated

2015 ◽  
Vol 8 (1) ◽  
pp. 102
Author(s):  
Zifeng Li
Keyword(s):  
Gravitational Field ◽  
Coordinate System ◽  
Celestial Body ◽  
Angular Speed ◽  
Calculation Error ◽  
Cartesian Coordinate System ◽  
Inertial Coordinate System ◽  
The Earth ◽  
The Galaxy ◽  
Cartesian Coordinate

<p class="1Body">Selection of the coordinate system is essential for rotation problems. Otherwise, mistakes may occur due to inaccurate measurement of angular speed. Approximate inertial coordinate system selections for rotation problems should be the gravitational field of the celestial body higher than the object being rotated: (1) the Earth fixed Cartesian coordinate system for normal rotation problem; (2) heliocentric - geocentric Cartesian coordinate system for satellites orbiting the Earth; (3) the Galaxy Heart - heliocentric Cartesian coordinates for Earth's rotation around the Sun. In astrophysics, mass calculation error and angular velocity measurement error lead to a black hole conjecture.</p>

scholarly journals Does Combining Severe and Mild Cases of COVID-19 Produce Low Fatality Rates After Treatment With Hydroxychloroquine and Azithromycin?

2020 ◽  
Vol 189 (11) ◽  
pp. 1227-1229 ◽  
Author(s):  
Vincent Fleury
Keyword(s):  
High Risk ◽  
Data Collection ◽  
Outpatient Treatment ◽  
Calculation Error ◽  
High Risk Patients ◽  
Risk Patients

Abstract In this issue of the Journal, Dr. Risch (Am J Epidemiol. 2020;189(11):1218–1226) posits that the use of a combination of hydroxychloroquine and azithromycin as an outpatient treatment for high-risk patients with coronavirus 19 should be increased as a way to help curtail the ongoing pandemic. However, a calculation error occurred in the original article, and new data about the studies cited have come to light. Peculiarities in the methods of data collection and reporting in those original sources must be considered when evaluating the evidence for or against hydroxychloroquine and azithromycin bitherapy.

scholarly journals Study on Foundation Pit Construction Cost Prediction Based on the Stacked Denoising Autoencoder

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Lanjun Liu ◽  
Denghui Liu ◽  
Han Wu ◽  
Junwu Wang
Keyword(s):  
Influencing Factors ◽  
Construction Cost ◽  
Average Error ◽  
Support Vector ◽  
Calculation Error ◽  
Denoising Autoencoder ◽  
Construction Costs ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Project Construction

To accurately predict the construction costs of foundation pit projects, a model based on the stacked denoising autoencoder (SDAE) is constructed in this work. The influencing factors of foundation pit project construction costs are identified from the four attributes of construction cost management, namely, engineering, the environment, the market, and management. Combined with Chinese national standards and the practice of foundation pit project management, a method of the quantization of the influencing factors is presented. 60 deep foundation pit projects in China are selected to obtain 13 main characteristic factors affecting these project construction cost by using the rough set. Then, considering the advantages of the SDAE in dealing with complex nonlinear problems, a prediction model of foundation pit project construction costs is created. Finally, this paper employs these 60 projects for a case analysis. The case study demonstrates that, compared with the actual construction costs, the calculation error of the proposed method is less than 3%, and the average error is only 1.54%. In addition, three error analysis tools commonly used in machine learning (the determination coefficient, root mean square error, and mean absolute error) emphasize that the calculation accuracy of the proposed method is notably higher than those of other methods (Chinese national code, the multivariate return method, the BP algorithm, the BP model optimized by the genetic algorithm, the support vector machine, and the RBF model). The relevant research results of this paper provide a useful reference for the prediction of the construction costs of foundation pit projects.

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