Journal articles: 'Error in leveling'

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Li, Shuailin, Yi Zhou, Deming Ou, and Wen Wang. "Research on Electromechanical Four-Point Leveling Control System Based on MPC." Frontiers of Mechatronical Engineering 2, no. 1 (May 28, 2020): 20. http://dx.doi.org/10.18282/fme.v2i1.840.

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<p>Multi-supporting leveling platform was wildly applied in areas of normal or military industry. To complete some frocking targets, it usually requires good performance of levelness and short time adjustment. It is very meaningful to enhance the automatic level of leveling platform by mining adaptive controlling algorithm which satisfied the levelling error and used shorter time. In this paper, four-point supporting electromechanical leveling system was set as the object to study. By analyzing the leveling characteristic of the system, appropriate leveling strategies were put forward. The simulation result of the system, whose model was built based on MPC, show that this way achieves good auto leveling performance.</p>

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Chen, Shao-Hsien, and Chi-Li Ji. "Level Detection Equipment for Measuring the Influence of Different Leveling Accuracies on Linear Error." Journal of Sensors 2021 (September 4, 2021): 1–15. http://dx.doi.org/10.1155/2021/5576999.

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This study developed a level detection equipment which is used in computer numerical control (CNC) machine tool to determine the impact of leveling accuracy on rectilinear motion accuracy. When the CNC precision machine tool has accuracy deterioration under external load or internal stress, mainly caused error is leveling error, this research and development equipment can immediate to analyze and measurement. The allowable error of leveling accuracy can be obtained after experimental validation. The kinematic error relatively increases with leveling error. When the leveling accuracy is within the allowable error, the kinematic error relatively decreases. The main kinematic error items measured in this study include EXX, EBY, EAX, and EYY. The level detection equipment is developed in this study, and the fuzzy regression analysis is used for modeling. The model that has high accuracy in the test of the X -axis is R 2 = 0.9764 and P = 0.0506 , and Y -axis is R 2 = 0.9756 and P = 0.0524 . In terms of filtering, Kalman filtering is used for signal processing, the measured values and X -axis and Y -axis after filtering are improved by 94.1% and 86.2%, respectively, the repeatability of this system is about A grade capability of precision (Cp), resolution is ±0.0001°, and the stability is at least B grade capability of accuracy (Ca). This equipment has the advantages of low cost, high precision, and 2-axis measurement. This machine tool which has the straightness increases with X and Y axes’ leveling accuracy errors, when the X / Y leveling accuracy is within ±0.01 mm/m, and there is the best straightness and conforms to the ISO230 standard (Lee et al., 2020).

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Zhou, Xian Ping, and Ming Sun. "Study on Accuracy Measure of Trigonometric Leveling." Applied Mechanics and Materials 329 (June 2013): 373–77. http://dx.doi.org/10.4028/www.scientific.net/amm.329.373.

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How to reduce the errors of the total station in vertical angle measurement is a main problem for improving the accuracy of trigonometric leveling. The leveling method combining the total station with a tracking bar is becoming increasingly more popular, and also the limitations of the traditional trigonometric leveling method have been shown. After a long period of exploration, a new method is proposed for trigonometric leveling. The results show that the error sources of trigonometric leveling are reduced by the method combining with the total station on any spot, and also instrument height and prism height are unnecessarily measured in each determination, so that the field workload and the error sources for improving accuracy are reduced, and then the accuracy of trigonometric leveling is further improved and the speed of implementing the leveling becomes faster. This height determination method is with certain applicability and reference value in the practical work.

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Han, Mao, and Mao Hua Liu. "Research on the Total Station Trigonometric Leveling Using Midway Method Replaces Three/Four Grade Leveling." Advanced Materials Research 971-973 (June 2014): 1144–47. http://dx.doi.org/10.4028/www.scientific.net/amr.971-973.1144.

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In order to improve the precise of trigonometric leveling, analysis of the midway method by theoretical analysis and experiment. A formula is derived to calculate the elevation difference and the mean square error base on the error propagation law. The result of research includes: the midway method of total station trigonometric leveling is simple operated , it can replaces the three/four grade leveling through a variety of correction under certain conditions.

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Huang, Haoping. "Airborne geophysical data leveling based on line-to-line correlations." GEOPHYSICS 73, no. 3 (May 2008): F83—F89. http://dx.doi.org/10.1190/1.2836674.

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A new technique removes the leveling errors in airborne geophysical data based on an assumption that the data are continuous (i.e., not renulled or recalibrated) from line to line. A single flight line is selected as a reference to level and tie all survey lines to this continuously varying datum. The leveling errors are determined in a least-squares sense from the reference line and the adjacent line to be leveled. The technique markedly improves the quality of the unleveled, raw data and works best if the reference line overlaps most of the line being leveled. This method cannot distinguish a linear geologic feature in the direction of flight lines from a leveling error. The technique initially was developed for airborne electromagnetic (EM) data in cases where tie-line leveling works poorly. However, it may also be used for airborne-magnetic and other data, in which case tie-lines used in conventional leveling techniques are not needed.

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Guo, Jin Yun, Lei Yu, Xin Liu, Qiao Li Kong, and Guo Wei Li. "Automatic Trigonometric Leveling System Based on GPS and ATR." Applied Mechanics and Materials 90-93 (September 2011): 2897–902. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.2897.

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Trigonometric leveling method is often used to connect the height over sea. Error analysis of trigonometric leveling is made. In order to automatically achieve the trigonometric leveling over long distance, an automatic trigonometric leveling system is put forward with the combination of GPS and the automatic target recognition (ATR) techniques in this paper. The primary design of the system prototype including the structure and the software is given. The practical principle tests are also made to prove the system performance. The results indicate that the leveling precision of the system can satisfy the requirement of fourth order leveling.

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Wang, Yuezong, Zhaodong Wang, Mengfei Guo, and Xin Zhang. "Research on an automatic leveling method with a feedback mode for a parallel 3D printer." Rapid Prototyping Journal 25, no. 7 (August 12, 2019): 1250–65. http://dx.doi.org/10.1108/rpj-03-2019-0052.

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Purpose The purpose of this study is to propose an automatic leveling method for a printing platform based on a three-point coordinate feedback. The proposed method is used in fused deposition modeling additive manufacturing systems. The coordinate error of the leveled plane is constrained to within Â ± 0.2 mm, which is less than the printed layer thickness. Design/methodology/approach First, the model of the forward and inverse solutions of the parallel arm is obtained based on the principles of vector algebra. Second, the automatic leveling mechanism for collecting the z-coordinate is designed. The best position of the virtual origin plane is obtained by comparing the z-coordinates of the test points. Finally, after making multiple adjustments through a closed-loop z-coordinate feedback, the parallelism of the printing plane and the virtual origin plane is limited to an effective range. Findings The experimental results show that after three leveling attempts, the z-coordinate of the test points can be constrained to within Â ± 0.2 mm, which shows that this method can effectively achieve automatic leveling in a delta three-dimensional (3D) printer. Originality/value This study presents a novel and distinctive delta 3D printer leveling system by designing a leveling mechanism and a leveling algorithm. The method uses a closed-loop feedback mode to make the leveling process simple, convenient and efficient without requiring major changes to the printer. The error after leveling is less than the printed layer thickness, which fully guarantees the accuracy of the leveling process.

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Song, Kang, Jun Bi Liao, Chang Qing Lin, Xue Dong Cao, Yang Yu, and Rui Ji. "Study of Improvement of Measurement Precision for Roundness Measuring Instrument." Applied Mechanics and Materials 530-531 (February 2014): 117–26. http://dx.doi.org/10.4028/www.scientific.net/amm.530-531.117.

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Based on the requirement of small errors in measuring roundness (cylindricity) error, a leveling methodology which using a dual-point vertical layout has been put forward and analyzed. According to the direction cosine of the axis of workpiece, the amount of leveling has been defined and calculated, which overcomes the problem brought by manual adjustment technology and forms theoretical bases of fast, accurate leveling and high precise measurement. The assessment of roundness (cylindricity) error is to search for a center (cylinder axis) which satisfies the minimum condition. Due to the reliance of initial solutions and relative slowness in terms of convergence precision and convergence rate when using Nelder-Mead simplex method, a combinative method of Quasi-Newton and N-M simplex method has been proposed which achieves a fast, accurate search for global optimums. With the proof of the simulation of classical testing functions using Matlab and the measured data, the convergence rate and precision will be enhanced effectively has been certified with the combination of both methods mentioned above which ensuring and improving the measuring precision of workpiece.

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SONG Kang, 宋康, 廖俊必 LIAO Jun-bi, 林长青 LIN Chang-qing, and 曹学东 CAO Xue-dong. "Leveling and cylindricity error assessment for roundness measuring instrument." Optics and Precision Engineering 22, no. 12 (2014): 3360–67. http://dx.doi.org/10.3788/ope.20142212.3360.

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Zeng, Zhi-Lin, Guo-Hua Xu, Yin Zhao, and Fei Xie. "Adaptive Backstepping Controller Design for Leveling Control of an Underwater Platform Based on Joint Space." Journal of Control Science and Engineering 2014 (2014): 1–13. http://dx.doi.org/10.1155/2014/989717.

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This paper focuses on high precision leveling control of an underwater heavy load platform, which is viewed as an underwater parallel robot on the basis of its work pattern. The kinematic of platform with deformation is analyzed and the dynamics model of joint space is established. An adaptive backstepping controller according to Lyapunov's function is proposed for leveling control of platform based on joint space. Furthermore, the “lowest point fixed angle error” leveling scheme called “chase” is chosen for leveling control of platform. The digital simulation and practical experiment of single joint space actuator are carried out, and the results show high precision servo control of joint space. On the basis of this, the platform leveling control simulation relies on the hardware-in-loop system. The results indicate that the proposed controller can effectively restrain the influence from system parameter uncertainties and external disturbance to realize high precision leveling control of the underwater platform.

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Sun, Chungeng, and Ruibo Yuan. "Adaptive robust cross-coupling position synchronization control of a hydraulic press slider-leveling." Science Progress 104, no. 1 (January 2021): 003685042098703. http://dx.doi.org/10.1177/0036850420987037.

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To achieve a high performance synchronized motion trajectory tracking of the hydraulic press slider-leveling electrohydraulic control system, an adaptive robust cross-coupling control strategy that incorporates the cross-coupling approach into adaptive robust control (ARC) architecture has been proposed. The primary objective of this study was describe that the nonlinear ARC controller together with a cross-coupling control (CCC) controller was integrated to solve the slider-leveling synchronization control system using four axes. A discontinuous projection-based ARC controller was constructed. A robust control method with dynamic compensation type fast adaptation was introduced to attenuate the effects of parameter estimation errors, unmodeled dynamics and disturbances, and improved the transient tracking performance of the system. The stability of the controller was proven by Lyapunov theory and the trajectory tracking error asymptotically convergences to zero. The simulation of a desired reference trajectory was included. The max tracking error of the proposed ARC controller of single axis was kept within—0.06 mm. The trajectory tracking error asymptotically converges to zero, which guaranteed the system would possess good transient behavior and confirmed the stability performance of the control system. The four axes synchronous errors of reference trajectory with cross-coupling controller indicated the maximum synchronization error of the proposed ARC + CCC controller between axis was within ±0.1 mm. The ARC together with a CCC controller for four hydraulic cylinders used parameter adaptation to obtain estimates of model parameters for reducing the extent of parametric uncertainties, and used a robust control law to attenuate the effects of parameter estimation errors, unmodeled dynamics, and disturbances. This study result shows that the proposed cross-coupling synchronization control scheme, together with the ARC law, provides excellent synchronization motion performance in a control system with four axes.

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Markovich, K. I. "Reduction of geometric leveling results to a system of normal heights using the global gravity models of the Earth." Geodesy and Cartography 935, no. 5 (June 20, 2018): 2–9. http://dx.doi.org/10.22389/0016-7126-2018-935-5-2-9.

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The possible range of application of models of the Earth’s gravitational field is considered in the article by reducing the results of geometric leveling to a system of normal heights. The accuracy of the global gravity models EGM2008, EIGEN-6C4, GECO on the gravity acceleration differences calculated for the territory of the Republic of Belarus by the results of instrumental gravimetric measurements and obtained from gravity models was estimated. Areas of Belarus are determined for which the gravitational correction for the transition to the system of normal heights will be caused by the deviation of the level surfaces of the normal gravitational field from the actual, and not by the errors of the gravitational models in the form of acceleration of gravity. It is shown that the error of the gravitational correction obtained from the data of gravity models for the territory of Belarus is many times less than the permissible random mean error of geometric leveling of the first class.

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Wang, Xin, Hong Min Zhang, and Jia Bao Fang. "Research on Electro-Hydraulic Proportional Leveling System of Large Aerial Work Platform Based on Fuzzy PID." Applied Mechanics and Materials 58-60 (June 2011): 221–26. http://dx.doi.org/10.4028/www.scientific.net/amm.58-60.221.

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Aiming at electro-hydraulic proportional leveling system of large aerial work platform, the model of the system is established and the stability is validated. Because the parameters of traditional PID can be used one state only, the leveling performance of large aerial work platform changes with the change of radius-changing velocity. Fuzzy logic is used to PID control, whose parameters can be adjusted automatically according to error and error changing. A comparison analysis between PID and Fuzzy PID is carried with the help of AMESim/Simulink. The simulation results show that the fuzzy PID has better effects and robustness.

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Ma, Xiang Hui, Song Ye, Xiao Lei Wang, Chang Ye Yang, Jun Guo, and Teng Su. "The Design of Wave Height Standard Device in the WTTVS and its Error Analysis." Applied Mechanics and Materials 599-601 (August 2014): 493–98. http://dx.doi.org/10.4028/www.scientific.net/amm.599-601.493.

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To make up the shortage of the existing calibration equipments of the wave measurement instruments, the WTTVS is designed, and the design of the wave height standard device as a subsystem of the WTTVS is introduced in this paper. The subsystem consists of two invar leveling staffs, a laser range finder and an incremental encode, in which the invar leveling staffs and the laser range finder are used to calibrate the encode. At the same time, the uncertainty of the subsystem is evaluated. As the result, the uncertainty is 3.48mm (confidence probability is 99%), which proves the feasibility of the design.

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Wang, Liu, Lin Fang, BO Zhang, and Chang Cheng Huang. "Error Analysis of the Settlement Observation." Applied Mechanics and Materials 580-583 (July 2014): 2801–4. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.2801.

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This document bases on settlement observation of a residential district which is influenced by the subway construction in Shanghai China.Because of the long-term measurement,there were some equipment boxes installed on the top of the settlement marks.Thus making the leveling rod in an leaning angle to the right or left direction relative to the sight line.In order to know the error of the measurement,we make analysis of the error.And it also can be a reference for other surveyings when encounter this similar circumstance.

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Yagudina, E. I. "The Problem of the Leveling of the Reserved Net of Arcs at the Celestial Sphere by the Construction of the Reference Coordinate System." Symposium - International Astronomical Union 141 (1990): 96. http://dx.doi.org/10.1017/s0074180900086423.

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The methods of the rational leveling of the results of the observations of the angular distances between quasars by VLBI method were suggested. The application of these methods on the model of reserved net on sphere shows a descrease of the standard error of the quasers' coordinates after leveling by a factor of three times. We employed 10 elementary configurations constructed on 20 chosen quasars in the Northern hemisphere.

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FEDORCHUK, A. "Analysis of erypsoidal heights errors based on GNSS-leveling results." Modern achievements of geodesic science and industry 41, no. I (April 1, 2021): 37–45. http://dx.doi.org/10.33841/1819-1339-1-41-37-45.

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Research the influence of errors on the measurement results is always an urgent task. Analysis of such values makes it possible to assess the nature of the change and the magnitude of the impact of errors for their further consideration or compensation, or minimization. In this paper, the errors in determining ellipsoidal heights from GNSS observations are considered. In determining the ellipsoidal heights, this method can achieve an accuracy of 1–2 cm in static mode (Static) and 2–4 cm in real time mode (RTK). Thus, the accuracy of the chosen mode of observations will indicate the initial limits of the ellipsoidal heights errors influence, and the factors that arise directly during observations and data processing will determine the extent to which these errors will change relative to the initial limits. The purpose of this work is to analyze the errors of ellipsoidal heights based on the results of GNSS-leveling obtained in the static and RTK modes. Method. The study used GNSS-leveling data at 17 points (wall and soil benchmarks) of leveling lines of I–II classes, which are located within a radius of 15 km from the permanent station SULP of the Lviv Polytechnic National University. Observations were performed in static mode (4-hour) and RTK (8–10 measurements). Points are divided into three categories (5–6 points): 1) statics on wall benchmarks; 2) real-time mode on wall benchmarks; 3) static mode on soil benchmarks. By combining methods and categories, four GNSS networks were formed, including 11, 11, 12 and 17 points. Results. For each category, the percentages within which the errors of ellipsoidal heights change in static observation mode and real-time mode using the GNSS leveling method are presented. On the basis of the received information it is established that for the first case errors of ellipsoidal heights on the average change within ± 43 %, for the second ± 36 %, and for the third ± 14 %. The analysis of statistical characteristics for each category shows that the standard deviation of the static mode data is 2 % and 19 %, and the RTK mode – 12 %, respectively. Scientific novelty and practical significance. The nature of the change in the error limits of the ellipsoidal heights determination gives an idea of what accuracy should be expected when performing GNSS-leveling depending on the mode of observation. Such data play an important role in solving scientific and applied problems by GNSS leveling, such as the constructions of new leveling networks or monitoring the height points of existing networks.

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Hamilton, Mark A. "Schematizing as a Measure of Leveling-Sharpening." Perceptual and Motor Skills 73, no. 1 (August 1991): 95–102. http://dx.doi.org/10.2466/pms.1991.73.1.95.

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A computer-administered schematizing test was used to assess three measures of leveling-sharpening: accuracy scores, incremental difference scores, and rate of change scores. Reliability and correlational analyses of 119 subjects' responses showed that the mean accuracy measure was superior to the ranking accuracy, incremental error, incremental discrepancy, and response-lag measures. Analysis also indicated that a 50-trial version of the schematizing test would be as reliable as a 150-trial version.

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Tosselli, Laura, Verónica Bogado, and Ernesto Martínez. "Multi-agent Learning by Trial and Error for Resource Leveling during Multi-Project (Re)scheduling." Journal of Computer Science and Technology 18, no. 02 (October 9, 2018): e14. http://dx.doi.org/10.24215/16666038.18.e14.

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In a multi-project context within enterprise networks, reaching feasible solutions to the (re)scheduling problem represents a major challenge, mainly when scarce resources are shared among projects. The multi-project (re)scheduling must achieve the most efficient possible resource usage without increasing the prescribed project constraints, considering the Resource Leveling Problem (RLP), whose objective is to level the consumption of resources shared in order to minimize their idle times and to avoid overallocation conflicts. In this work, a multi-agent solution that allows solving the Resource Constrained Multi-project Scheduling Problem (RCMPSP) and the Resource Investment Problem is extended to incorporate indicators on agents’ payoff functions to address the Resource Leveling Problem in a decentralized and autonomous way, through decoupled rules based on Trial-and-Error approach. The proposed agent-based simulation model is tested through a set of project instances that vary in their structure, parameters, number of resources shared, etc. Results obtained are assessed through different scheduling goals, such as project total duration, project total cost and leveling resource usage. Our results are far better compared to the ones obtained with alternative approaches. This proposal shows that the interacting agents that implement decoupled learning rules find a solution which can be understood as a Nash equilibrium.

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Trevoho, Ihor, Fedir Zablotskyi, Andrzej Piskorek, Bohdan Dzhuman, and Andriy Vovk. "GEODESY, CARTOGRAPHY, AND AERIAL PHOTOGRAPHY." GEODESY, CARTOGRAPHY, AND AERIAL PHOTOGRAPHY 93,2021, no. 93 (June 23, 2021): 13–26. http://dx.doi.org/10.23939/istcgcap2021.93.013.

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Purpose. The purpose of this work is obtaining connections between the Baltic and European height systems based on the I class leveling between the Ukrainian and Polish control points of the base vertical networks and construction of the quasigeoid surface on the border area. Method. Full integration of the hight system of Ukraine into the European vertical reference system (EVRS) consists of two stages: modernization of the height network of Ukraine through its integration into the United European leveling network UELN; construction and use as a regional vertical date the model of high-precision quasigeoid, which will be consistent with the European geoid EGG2015. The analysis of methods of high-precision leveling in Ukraine and Poland, and also the analysis of methods of construction of quasigeoid models in these countries is performed. Results. For integrating the Ukrainian hight system into the UELN/EVRS2000 system, the Ukrainian side performed I class geometric leveling along two lines: Lviv - Shehyni - Przemysl and Kovel - Yagodyn - Chelm with total length of 196 km. The root mean square systematic error on both lines of leveling was s<0.01 mm/km. In turn, the mean square random error along the line Lviv - Shehyni - Przemysl is h=0.29 mm/km, and along the line Kovel - Yagodyn - Chelm is h=0.27 mm/km. For double control on the cross-border part, the Polish side performed high-precision leveling with a length of 33 km. The differences between the Ukrainian and Polish leveling in all sections are within the tolerance. The analysis of influence of geodynamic phenomena on control of high-precision leveling is carried out. GNSS-leveling was performed on all fundamental and ground benchmarks, as well as horizontal marks. These measurements were used to build a quasigeoid model for the border area of Ukraine. The MSE of the obtained quasigeoid model is about 2 cm, which corresponds to the accuracy of the input information. Scientific novelty and practical significance. The connection of the Ukrainian and European height systems will ensure Ukraine’s integration into the European economic system, participation in international research of global ecological and geodynamic processes, study of the Earth’s shape and gravitational field and mapping of Ukraine using navigational and remote-sensing satellite technologies. Calculation of a high-precision model of a quasigeoid on the Ukraine area in relation to the European height system, agreed with the European geoid EGG2015, will allow to obtain gravity-dependent heights using modern satellite technologies.

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Tretyak, Kornyliy, and Ivan Brusak. "GEODESY, CARTOGRAPHY, AND AERIAL PHOTOGRAPHY." GEODESY, CARTOGRAPHY, AND AERIAL PHOTOGRAPHY 93,2021, no. 93 (June 23, 2021): 27–34. http://dx.doi.org/10.23939/istcgcap2021.93.027.

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Purpose. The purpose of this work is obtaining connections between the Baltic and European height systems based on the I class leveling between the Ukrainian and Polish control points of the base vertical networks and construction of the quasigeoid surface on the border area. Method. Full integration of the hight system of Ukraine into the European vertical reference system (EVRS) consists of two stages: modernization of the height network of Ukraine through its integration into the United European leveling network UELN; construction and use as a regional vertical date the model of high-precision quasigeoid, which will be consistent with the European geoid EGG2015. The analysis of methods of high-precision leveling in Ukraine and Poland, and also the analysis of methods of construction of quasigeoid models in these countries is performed. Results. For integrating the Ukrainian hight system into the UELN/EVRS2000 system, the Ukrainian side performed I class geometric leveling along two lines: Lviv - Shehyni - Przemysl and Kovel - Yagodyn - Chelm with total length of 196 km. The root mean square systematic error on both lines of leveling was s<0.01 mm/km. In turn, the mean square random error along the line Lviv - Shehyni - Przemysl is h=0.29 mm/km, and along the line Kovel - Yagodyn - Chelm is h=0.27 mm/km. For double control on the cross-border part, the Polish side performed high-precision leveling with a length of 33 km. The differences between the Ukrainian and Polish leveling in all sections are within the tolerance. The analysis of influence of geodynamic phenomena on control of high-precision leveling is carried out. GNSS-leveling was performed on all fundamental and ground benchmarks, as well as horizontal marks. These measurements were used to build a quasigeoid model for the border area of Ukraine. The MSE of the obtained quasigeoid model is about 2 cm, which corresponds to the accuracy of the input information. Scientific novelty and practical significance. The connection of the Ukrainian and European height systems will ensure Ukraine’s integration into the European economic system, participation in international research of global ecological and geodynamic processes, study of the Earth’s shape and gravitational field and mapping of Ukraine using navigational and remote-sensing satellite technologies. Calculation of a high-precision model of a quasigeoid on the Ukraine area in relation to the European height system, agreed with the European geoid EGG2015, will allow to obtain gravity-dependent heights using modern satellite technologies.

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Chen*, Y. Q., Adam Chrzanowski, and M. Kavouras. "Assessment of observations using minimum norm quadratic unbiased estimation (minque)." CISM journal 44, no. 1 (April 1990): 39–46. http://dx.doi.org/10.1139/geomat-1990-0004.

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Estimation of the variances and covariances of observations in geodetic and engineering surveys of high precision is of great importance for proper weighting of the observations in their subsequent processing and for better understanding of sources of errors and their modeling. The authors have adopted from modern statistics the Minimum Norm Quadratic Unbiased Estimation (MINQUE) method for the variance-covariance component estimation. The method has successfully been implemented in modeling the error propagation in geodetic leveling, in determination of error components and weighting of measurements with the Global Positioning System, and in an assessment of a triangulateration network observed with different EDM instruments.

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Mark, Robert K., Thomas D. Gilmore, and Robert O. Castle. "evidence of Suppression of the Unequal Refraction Error in Geodetic Leveling." Journal of Geophysical Research: Solid Earth 92, B3 (March 10, 1987): 2767–90. http://dx.doi.org/10.1029/jb092ib03p02767.

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Contreras-de-Villar, Francisco, Francisco J. García, Juan J. Muñoz-Perez, Antonio Contreras-de-Villar, Veronica Ruiz-Ortiz, Patricia Lopez, Santiago Garcia-López, and Bismarck Jigena. "Beach Leveling Using a Remotely Piloted Aircraft System (RPAS): Problems and Solutions." Journal of Marine Science and Engineering 9, no. 1 (December 26, 2020): 19. http://dx.doi.org/10.3390/jmse9010019.

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The size and great dynamism of coastal systems require faster and more automated mapping methods like the use of a remotely piloted aircraft system (RPAS) or unmanned aerial vehicle (UAV). This method allows for shorter intervals between surveys. The main problem for surveying using low-altitude digital photogrammetry in beach areas is their visual homogeneity. Obviously, the fewer the homologous points defined by the program, the lower the accuracy. Moreover, some factors influence the error performed in photogrammetric techniques, such as flight height, flight time, percentage of frame overlap (side and forward), and the number of ground control points (GCPs). A total of 72 different cases were conducted varying these factors, and the results were analyzed. Among the conclusions, it should be highlighted that the error for noon flights is almost double that for the early morning flights. Secondly, there is no appreciable difference regarding the side overlap. But, on the other side, RMSE increased to three times (from 0.05 to 0.15 m) when forward overlap decreased from 85% to 70%. Moreover, relative accuracy is 0.05% of the flying height which means a significant increase in error (66%) between flights performed at 60 and 100 m height). Furthermore, the median of the error for noon flights (0.12 m) is almost double that for the early morning flights (0.07 m) because of the higher percentage of grids with data for early flights. Therefore, beach levelings must never be performed at noon when carried out by RPAS. Eventually, a new parameter has been considered: the relationship between the number of GCPs and the surface to be monitored. A minimum value of 7 GCP/Ha should be taken into account when designing a beach leveling campaign using RPAS.

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Amor, Amine, Mohamed Rachik, and Hédi Sfar. "Combination of Finite-Element and Semi-Analytical Models for Sheet Metal Leveling Simulation." Key Engineering Materials 473 (March 2011): 182–89. http://dx.doi.org/10.4028/www.scientific.net/kem.473.182.

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Coiled sheet metal often exhibits shape defects that result from the rolling process or the coiling operation. To meet the quality requirement, these defects need to be removed using leveling and straightening. The process efficiency strongly depends on several parameters like the machine design, the rollers penetration and the sheet metal. Consequently, the leveling process is very sensitive and it is difficult to find the appropriate setting using trial and error procedure. In this context, numerical simulation can be very helpful. The aim of our work is to predict the residual curvature of the sheet knowing its initial shape and the leveling process settings. The simulation is carried out in two steps to integrate the global and the local behavior of the strip along the leveling process. In the first step, a 2D finite element model is used to predict the sheet metal deformations under the rollers action. In this first step the strip curvatures along the leveling machine are predicted. The so obtained results are then used to simulate the alternating bending and the spring back of the strip with the help of a semi-analytical model using the MATLAB programming environment. To validate the proposed approach, leveling tests were carried out on a 2.5 mm thickness sheet of DX51 steel and the measured residual curvatures are compared with the predictions. These comparisons show that satisfactory predictions can be obtained with good computational efficiency.

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Stein, Ross S., Charles T. Whalen, Sanford R. Holdahl, William E. Strange, and Wayne Thatcher. "Saugus-Palmdale, California, field test for refraction error in historical leveling surveys." Journal of Geophysical Research 91, B9 (1986): 9031. http://dx.doi.org/10.1029/jb091ib09p09031.

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Lu, Yong Zhi, Zhen Xing Su, Si Jia Wei, and Wang Biao Qiu. "Optimization Study on Leveling Cylinder Position of Telescopic Handler." Applied Mechanics and Materials 130-134 (October 2011): 2544–49. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.2544.

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According to research on the leveling principle of the telescopic handler fork, establishing relevant mathematical model to optimize the position of master cylinder with the optimization algorithm of accumulated error, least square method, and multi-objective programming of method of weighting by using the computer language of VB . Then the position of fork got optimization that stabilizes the level of fork of telescopic handler.

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Jia, Ning Ning, and Yong Hui Ge. "Remainder Reliability and Robust Estimation: A Case Study Using Twelve Simulated Leveling Networks." Applied Mechanics and Materials 263-266 (December 2012): 3163–67. http://dx.doi.org/10.4028/www.scientific.net/amm.263-266.3163.

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Total reliability, also called the average redundant observation component, is an indicator of a survey network. It summarily shows whether gross errors contained in observations on a survey network may be eliminated or weakened by robust estimation methods. Based on total reliability, the current paper presented the concept of remainder reliability, which essentially showed whether gross errors might be eliminated or weakened by robust estimation. Taking 12 leveling networks with different remainder reliability adjustments as examples, simulation experiments were used to compare 4 frequently used robust estimation methods. The results indicate that when observations simultaneously contain one gross error and if the remainder reliability RRg≥0.30 , robust estimation methods may eliminate or weaken these effects. However, if RRg>0.40, all the four robust estimation methods may effectively eliminate or weaken these effects.

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Prusakov, A. N., A. I. Spiridonov, and A. A. Prusakov. "The automated laser comparator for calibration of digital equipment leveling." Geodesy and Cartography 933, no. 3 (April 20, 2018): 17–22. http://dx.doi.org/10.22389/0016-7126-2018-933-3-17-22.

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Describes a device and methods for automated laser comparator for calibration of digital leveling equipment. The comparator created by the technology of the Finnish Geodetic Institute and placed in the building of the geodetic calibration laboratory of geodetic polygon of FSBE “Centre of geodesy, cartography and SDI”. Shows the main technical characteristics, modes of operation and basic procedures in the calibration of bar-code leveling rods. It is noted that the comparator is a complex measuring system in the form of high-precision optical-electronic stand, consisting of individual mechanical, optical and electronic components and assemblies. One of the features of the design of the comparator is the vertical positioning of its component parts, which allows to determine the error of position of the strokes of the scale of the rod in a working position. Based on the results of verification receive corrections to readings on a rod scale and a linear coefficient of expansion of the material from which rod is made. Lists the possible measurement errors in the verification process and the peculiarities of metrological assurance of operation of the comparator. Formulated one of the immediate tasks in the testing of the comparator

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Liao Feihong, 廖飞红, 李小平 Li Xiaoping, 陈学东 Chen Xuedong, and 李志丹 Li Zhidan. "Probe Spot Position Error on the Accuracy of Focusing and Leveling Measurement System." Acta Optica Sinica 30, no. 4 (2010): 1041–45. http://dx.doi.org/10.3788/aos20103004.1041.

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Beiki, Majid, Mehrdad Bastani, and Laust B. Pedersen. "Leveling HEM and aeromagnetic data using differential polynomial fitting." GEOPHYSICS 75, no. 1 (January 2010): L13—L23. http://dx.doi.org/10.1190/1.3279792.

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We introduce a new technique to level aerogeophysical data. Our approach is applicable to flight-line data without any need for tie-line measurements. The technique is based on polynomial fitting of data points in 1D and 2D sliding windows. A polynomial is fitted to data points in a 2D circular window that contains at least three flight lines. Then the same procedure is done inside a 1D window placed at the center of the 2D window. The leveling error is the difference between 1D and 2D polynomial fitted data at the center of the windows. To demonstrate the reliability of the method, it was tested on a synthetic aeromagnetic data set contaminated by some linear artifacts. Using the differential polynomial fitting method, we can remove the linear artifacts from the data. The method then was applied to two real airborne data sets collected in Iran. The leveling errors are removed effectively from the aeromagnetic data using the differential polynomial fitting. In the case of helicopter-towed electromagnetic (HEM) data, the polynomial fitting method is used to level the measured real (in-phase) and imaginary (quadrature) components, as well as the calculated apparent resistivity. The HEM data are sensitive to height variations, so we introduce an average-height scaling method to reduce the height effect before leveling in-phase and quadrature components. The method also is effective in recovering some of the attenuated anomalies. After scaling, the differential polynomial fitting method was applied to the data and effectively removed the remaining line-to-line artifacts.

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Pan, Yangyang, Guiqiang Dong, and Tong Zhang. "Error Rate-Based Wear-Leveling for nand Flash Memory at Highly Scaled Technology Nodes." IEEE Transactions on Very Large Scale Integration (VLSI) Systems 21, no. 7 (July 2013): 1350–54. http://dx.doi.org/10.1109/tvlsi.2012.2210256.

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柳, 飞. "Error Analysis for Measurement on Vertical Deformation of Existing Subway by Hydrostatic Leveling Sensor." Hans Journal of Civil Engineering 09, no. 03 (2020): 185–92. http://dx.doi.org/10.12677/hjce.2020.93021.

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34

Sylvester, Arthur, and Robert Smith. "Survey of Precise Leveling Array Grand Teton National Park." UW National Parks Service Research Station Annual Reports 18 (January 1, 1994): 145–51. http://dx.doi.org/10.13001/uwnpsrc.1994.3217.

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Fifteen permanent bench marks were established east and south of the existing 22 km-long line of 50 bench marks across the Teton normal fault in Grand Teton National Park to compare height changes of Jackson Hole relative to the Teton Range on the west and Shadow Mountain on the east. The new bench marks, together with three other agency bench marks and three temporary bench marks, constitute a 7. 8 km-long extension to the existing line tied to the old line at bench mark GT01. The new bench marks were precisely leveled between 30 August and 5 September 1994. Misclosure of the double-run survey was 0.86 mm, thus the precision of the total survey is 1 part in 10 million. If the misclosure is simply spread equally among the (n-1) bench marks, then the probable error associated with the relative height of a single bench mark is effectively zero.

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Wu, Qiong, Hongyao Wang, Bin Wang, Shengbo Chen, and Hongqing Li. "Performance Comparison of Geoid Refinement between XGM2016 and EGM2008 Based on the KTH and RCR Methods: Jilin Province, China." Remote Sensing 12, no. 2 (January 18, 2020): 324. http://dx.doi.org/10.3390/rs12020324.

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The selection of an appropriate global gravity field model and refinement method can effectively improve the accuracy of the refined regional geoid model in a certain research area. We analyzed the accuracy of Experimental Geopotential Model (XGM2016) based on the GPS-leveling data and the modification parameters of the global mean square errors in the KTH geoid refinement in Jilin Province, China. The regional geoid was refined based on Earth Gravitational Model (EGM2008) and XGM2016 using both the Helmert condensation method with an RCR procedure and the KTH method. A comparison of the original two gravity field models to the GPS-leveling benchmarks showed that the accuracies of XGM2016 and EGM2008 in the plain area of Jilin Province are similar with a standard deviation (STD) of 5.8 cm, whereas the accuracy of EGM2008 in the high mountainous area is 1.4 cm better than that of XGM2016, which may be attributed to its low resolution. The modification parameters between the two gravity field models showed that the coefficient error of XGM2016 model was lower than that of EGM2008 for the same degree of expansion. The different modification limits and integral radii may produce a centimeter level difference in global mean square error, while the influence of the truncation error caused by the integral was at the millimeter level. The terrestrial gravity data error accounted for the majority of the global mean square error. The optimal least squares modification obtained the minimum global mean square error, and the global mean square error calculated based on XGM2016 model was reduced by about 1~3 cm compared with EGM2008. The refined geoid based on the two gravity field models indicated that both KTH and RCR method can effectively improve the STD of the geoid model from about six to three centimeters. The refined accuracy of EGM2008 model using RCR and KTH methods is slightly better than that of XGM2016 model in the plain and high mountain areas after seven-parameter fitting. EGM2008 based on the KTH method was the most precise at ± 2.0 cm in the plain area and ± 2.4 cm in the mountainous area. Generally, for the refined geoid based on the two Earth gravity models, KTH produced results similar to RCR in the plain area, and had relatively better performance for the mountainous area where terrestrial gravity data is sparse and unevenly distributed.

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Li, Si Hai, Gong Min Yan, Peng Xiang Yang, and Yong Yuan Qin. "A Rapid Initial Alignment Alogrithm Based on Strapdown Gyrocompass." Advanced Materials Research 532-533 (June 2012): 1563–67. http://dx.doi.org/10.4028/www.scientific.net/amr.532-533.1563.

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The basic principles for stabilized gyrocompass initial alignment are analyzed in platform inertial navigation system (PINS), then similar principles and initial alignment algorithms suitable for programming are proposed for strapdown inertial navigation system (SINS). The scheme of SINS gyrocompass initial alignment can be divided into four steps, including leveling alignment with header uncertainty, coarse header alignment, leveling realignment and gyrocompass alignment for header. By simplifying SINS nonlinear error model under header uncertainty, the formula of coarse header alignment is deduced. On the assumption of navigation computer having large memory and powerful computing ability, and basing on the ‘multiformity’ of SINS mathematical platform and the ability to attitude reverse control, a specific progress for SINS rapid gyrocompass alignment is introduced and designed in detail. Finally, some tests prove that the proposed alignment algorithm in this paper is effective.

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Jia, Hanwen, Guanwen Cheng, Jiaxiang Li, Honglei Liu, and Jiawei Qian. "A correction method for the ambient temperature-induced error in hydrostatic leveling systems and application." Measurement 172 (February 2021): 108880. http://dx.doi.org/10.1016/j.measurement.2020.108880.

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38

Hwang, Sang-Ho, Jong Wook Kwak, and Chang-Hyeon Park. "Cold Data Identification using Raw Bit Error Rate in Wear Leveling for NAND Flash Memory." Journal of the Korea Society of Computer and Information 20, no. 12 (December 30, 2015): 1–8. http://dx.doi.org/10.9708/jksci.2015.20.12.001.

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39

Noeiaghdam, Samad, Aliona Dreglea, Jihuan He, Zakieh Avazzadeh, Muhammad Suleman, Mohammad Ali Fariborzi Araghi, Denis N. Sidorov, and Nikolai Sidorov. "Error Estimation of the Homotopy Perturbation Method to Solve Second Kind Volterra Integral Equations with Piecewise Smooth Kernels: Application of the CADNA Library." Symmetry 12, no. 10 (October 20, 2020): 1730. http://dx.doi.org/10.3390/sym12101730.

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This paper studies the second kind linear Volterra integral equations (IEs) with a discontinuous kernel obtained from the load leveling and energy system problems. For solving this problem, we propose the homotopy perturbation method (HPM). We then discuss the convergence theorem and the error analysis of the formulation to validate the accuracy of the obtained solutions. In this study, the Controle et Estimation Stochastique des Arrondis de Calculs method (CESTAC) and the Control of Accuracy and Debugging for Numerical Applications (CADNA) library are used to control the rounding error estimation. We also take advantage of the discrete stochastic arithmetic (DSA) to find the optimal iteration, optimal error and optimal approximation of the HPM. The comparative graphs between exact and approximate solutions show the accuracy and efficiency of the method.

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Fan, Gui Ju, Yong Zhen Wang, and Xiao Hui Zhang. "Development and Experiment of Lifting Platform for Orchards in Hilly Area." Applied Mechanics and Materials 865 (June 2017): 111–17. http://dx.doi.org/10.4028/www.scientific.net/amm.865.111.

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At present, pruning of fruit trees on hills is mainly completed by climbing on trees or ladder, which could cause injury due to poor landform. In order to avoid such kind of risks, it is important to develop a lifting platform for orchards in hilly area. In this paper its structure and working mechanism were introduced. This lifting platform, as a machine, is comprised of power device, elevating mechanism, leveling mechanism, slewing mechanism, supporting mechanism and hydraulic control system, and is driven by a small four-wheel tractor. Its hydraulic system can control hydraulic cylinders to extend and retract so as to lift, lower, rotate or keep platform at horizontal position. By analyzing the machine’s kinematic model, the mode of hydrostatic triangle leveling was determined. In order to simplify the machine’s structure, a cantilever beam was used as a supporting mechanism. After carried out the performance test for the machine, the results show that the machine has the following features: stable working performance, the maximum load up to 150 kg, the lifting height 1.5 m, the rotating speed 1 r/min, the lifting velocity 0.1 m/s, and leveling error in lifting process no more than 2° (no matter on horizontal plane or on slopes). So the machine can be suitable for sloped terrain, and the design requirements are well satisfied.

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41

Herbert, Tata, and Raufu Ibrahim Olatunji. "Comparative Analysis of Change between Ellipsoidal Height Differences and Equivalent Orthometric Height Difference." Ghana Journal of Geography 12, no. 1 (July 25, 2020): 132–44. http://dx.doi.org/10.4314/gjg.v12i1.7.

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Height is an important component in the determination of the position of a point. The study aimed at performing a comparative analysis of change between ellipsoidal height differences and the equivalent orthometric height difference of points. A hi-target Differential Global Positioning System (DGPS) was used to acquire GPS data with an occupation period of thirty (30) minutes on each point, which were processed using Hi-target Geomatics Office (HGO) software to obtain the ellipsoidal heights. An automatic level instrument was used to acquire leveling data, which were processed using the height of collimation method to obtain the orthometric heights. A total of fifty (50) points were occupied as common points for both the GPS and levelling observations at 20-meter intervals. The accuracy of the height difference was determined using standard deviation with the ellipsoidal height difference as 53.59cm and the orthometric height as 53.07cm respectively. A Root Mean Square Error value of 0.0621m was obtained as the accuracy of the change between the two height differences. Statistical analysis using the independent-sample Z test was used to analyze the data at a 5% significant level. The result shows no significant difference in the performance of the two height systems. It is worthy to note that GPS and spirit levelling height differences can be used interchangeably for any heighting in short distances for surveying and engineering applications.

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42

Wang, De Bao, Xue Ling Fang, Zhao Bo Xing, and Jun Huang. "The Establishment of Geodetic Datum in Jiaonan City." Applied Mechanics and Materials 170-173 (May 2012): 2864–69. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.2864.

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As to Jiaonan geodetic datum, third-order horizontal control network is established through GPS while third-order leveling network is established through electronic level. This paper illustrates how to process data so as to improve horizontal and vertical precision in the process of establishing third-order horizontal control network and elevation fitting. It puts forward such an opinion: making precision test for starting points of horizontal network and preserving those short baselines of low precision in unconstraint three-dimensional adjustment；As to elevation fitting, we advocates employing a variety of fitting scheme make precision inspection for those known GPS leveling points as well as those unknown points’ fitting level. Then the most probable level is just what we get. Afterwards, we calculate those unknown points’ root mean square error of fitting height, plus the minimum and maximum difference between fitting height and the most probable height. Taking all the results of precision inspection into consideration, we can find out the best fitting scheme, which improves the systematic precision and reliability of geodetic datum.

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43

Gong, Yu Sheng, Qian Han, and Li Ping Zhang. "Research into the Model of GNSS Leveling Polynomial Surface Fitting Based on MATLAB." Applied Mechanics and Materials 90-93 (September 2011): 2907–12. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.2907.

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To make full use of geodetic height results measured by GNSS and improve the accuracy that GNSS geodetic height convert to normal height, method of polynomial surface fitting has been selected in this article to research into fitting of the elevation. In the first place, for least squares estimation do not have the ability of resisting gross error, robust estimation is introduced to data preprocessing, which has solve the problem of distortion model effectively and then combines with specific engineering to make comparison and to analyze accuracy of polynomial surface fitting data of different orders. MATLAB has been used in programming design in the whole process, which has realized automatic processing of data.

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Liu, Li Long, Teng Xu Zhang, Miao Zhou, Lin He, and Liang Ke Huang. "The Research of GPS Elevation Fitting Considering the Influence of Covariance Function." Applied Mechanics and Materials 568-570 (June 2014): 114–20. http://dx.doi.org/10.4028/www.scientific.net/amm.568-570.114.

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The common method to determine Quasi-Geoids is GPS leveling however the Quasi-Geoid of this method determined is a kind of trend surface which not take the physical property of geoid into consideration, and the fitting method is surface fitting which only consider the surveying error, lead to inaccurate fitting result. In allusion to these problems, Remove-restore method is used to remove the long wave information of earth gravity field model to get more smooth residual gravity height anomaly, then compared the influence of different covariance function to the fitting result of least square collocation which take surveying error and model error into account. The results show that Gaussian and resemble Gaussian function can achieve higher fitting precision to the large area with height anomaly value changes significance; the Remove-restore method can effectively improve the fitting precision to least square collocation method which depend on the covariance value of each points.

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45

Ling, Xuan, Xiao-hui Li, Yu-quan Zhu, and Tian-lin Feng. "Quantitative feedback theory and zero phase error tracking control combined robust control for radar truck leveling simulator." Journal of Shanghai University (English Edition) 13, no. 5 (October 2009): 384–90. http://dx.doi.org/10.1007/s11741-009-0509-3.

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46

Esina, Ekaterina N., and Vladislava V. Likhodeevskaya. "Development of methods for equalizing level networks." RUDN Journal of Engineering Researches 21, no. 1 (December 15, 2020): 58–65. http://dx.doi.org/10.22363/2312-8143-2020-21-1-58-65.

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The article is devoted to comparison of methods of calculating the approximate elevations of nodal points when adjusting leveling networks by strict and non-strict methods. Ensuring geomechanical monitoring of the mutual influence of constructed and operated objects is important in the intensive development of underground space of megacities, the construction of unique objects and structures. In the course of the research, mathematical models of level networks were developed and presented in the form of a closed loop and a set of open polygons. Analysis of modeling allows to determine the feasibility of applying the knot method by Professor V.V. Popov instead of the parametric method of adjustment. It is established that the quality of the results of strict equalization depends entirely on the quality of measurements, since deviations from the true values do not exceed the measurement error. The research has shown that it is possible to simplify the processing of monitoring data and evaluation of various configuration options for leveling networks, using algorithms for calculating approximate marks of nodal points. This makes it easier to process monitoring results and evaluate various network configuration options while ensuring the required level of measurement accuracy.

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Yao, Guo Nian, Jun Hu Wei, Hao Sun, and Guo Ji Sun. "Research for an Automatic Measurement System for Centroidal Deviation of Projectiles Based on Three Points Method." Applied Mechanics and Materials 26-28 (June 2010): 1–4. http://dx.doi.org/10.4028/www.scientific.net/amm.26-28.1.

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In order to improve the measuring accuracy and efficiency of projectiles’ centroidal deviation, the working principle and the relevant calculation formulae based on three points method are described in detail, the main factors affecting precision are discussed and quantitative analysis on precision of the equipment is made. The measuring platform with automatic leveling and locating based on the arc locating and so on are put forward to reduce error. The experimental results show that the system can satisfy the requirement for measuring with high accuracy. The equipment plays a very important role in testing ordnance, especially for measuring regular projectiles.

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Tan, Xianfeng, Bingzhong Song, Huaizhi Bo, Yunwei Li, Meng Wang, and Guohong Lu. "Extraction of Irregularly Shaped Coal Mining Area Induced Ground Subsidence Prediction Based on Probability Integral Method." Applied Sciences 10, no. 18 (September 22, 2020): 6623. http://dx.doi.org/10.3390/app10186623.

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Underground coal mining-induced ground subsidence (or major ground vertical settlement) is a major concern to the mining industry, government and people affected. Based on the probability integral method, this paper presents a new ground subsidence prediction method for predicting irregularly shaped coal mining area extraction-induced ground subsidence. Firstly, the Delaunay triangulation method is used to divide the irregularly shaped mining area into a series of triangular extraction elements. Then, the extraction elements within the calculation area are selected. Finally, the Monte Carlo method is used to calculate extraction element-induced ground subsidence. The proposed method was tested by two experimental data sets: the simulation data set and direct leveling-based subsidence observations. The simulation results show that the prediction error of the proposed method is proportional to mesh size and inversely proportional to the amount of generated random points within the auxiliary domain. In addition, when the mesh size is smaller than 0.5 times the minimum deviation of the inflection point of the mining area, and the amount of random points within an auxiliary domain is greater than 800 times the area of the extraction element, the difference between the proposed method-based subsidence predictions and the traditional probability integral method-based subsidence predictions is marginal. The measurement results show that the root-mean-square error of the proposed method-based subsidence predictions is smaller than 3 cm, the average of absolute deviations of the proposed method-based subsidence predictions is 2.49 cm, and the maximum absolute deviation is 4.05 cm, which is equal to 0.75% of the maximum direct leveling-based subsidence observation.

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Gu, Sheng Li, and Fu Ming Wang. "Evolutionary Structural Shape Optimization Based on Adaptive FEM and Boundary Representation of B-Spline." Advanced Materials Research 562-564 (August 2012): 1575–82. http://dx.doi.org/10.4028/www.scientific.net/amr.562-564.1575.

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This paper presents a structural shape optimization algorithm based on the evolutionary structural optimization (ESO) method in conjunction with element error estimate and adaptive FEM. B-splines are used to describe the boundary of the design domain; the shape of these B-splines is governed by a set of master nodes which can be taken as the design variables. The optimal shape of the design boundary with constant stress is achieved iteratively by the movement and update of the position of the master nodes based on nodal stress leveling. The result quality, in terms of accuracy and efficiency, is tested and discussed with an analytical solution.

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Nikonov, Anton, and Irina Chesheva. "ACCURACY OF THE GEODETIC CONTROL NETWORK DEVELOPED BY LAND METHODS." Interexpo GEO-Siberia 1, no. 1 (2019): 130–43. http://dx.doi.org/10.33764/2618-981x-2019-1-1-130-143.

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The article gives comparative analysis of the creating horizontal and vertical geodetic control network for the purposes of research and building. It is recommended to create geodetic network on the territory up to 1–2 sq km by means of linear-angular measurements with the accuracy of urban fourth-order traverse. After centering the total station and the reflector with an error not more than 1 mm, the minimal network side is 140 m. The precalculation of geodetic control network accuracy with the given confidence level can be performed in CredoDAT. Creation of vertical and horizontal geodetic network should go simultaneously – by means of reciprocal trigonometric leveling of III–IV order accuracy. The height of the total station with use of specific tape measurer Leica can be measured with error of up to 1 mm. The requirements of the acting set of rules «Geodetic works in construction» are not always substantiated and require careful attitude.

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Journal articles on the topic 'Error in leveling'

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