scholarly journals Calibration

2019 ◽  
Vol 124 ◽  
Author(s):  
Lane C. Sander
Keyword(s):  
Mathematical Models ◽  
Linear Model ◽  
Instrumental Response ◽  
Measurement Accuracy ◽  
Calibration Model ◽  
Mathematical Relationship ◽  
Chemical Metrology ◽  
Advantages And Disadvantages ◽  
Calibration Models ◽  
Improve Measurement

In the context of chemical metrology, calibration is the process of relating a known quantity of an analyte to the corresponding measured instrumental response through a mathematical relationship. Calibration permits the assignment of analyte levels in unknown samples based on the known levels of the calibrants. Details of the calibration model are important to achieve accurate results. Several common approaches are used in calibrating methods. Most frequently, calibration models are based on linear instrumental response, with mathematical models that include zero intercept, fixed intercept, unconstrained (fitted), and bracketed models. When instrumental response is nonlinear, a linear model may still provide accurate results if the calibration range is sufficiently limited. This presentation will provide an overview and application of various calibration models, with recommendations of ways to improve measurement accuracy. Examples are presented that illustrate advantages and disadvantages for each of these models as applied to low level samples and to unknowns with levels that span several orders of magnitude.

scholarly journals AN ITERATIVE APPROACH FOR SELF-CALIBRATING BUNDLE ADJUSTMENT

2020 ◽  
Vol XLIII-B2-2020 ◽  
pp. 97-102
Author(s):  
J. L. Wang
Keyword(s):  
Camera Calibration ◽  
Measurement Accuracy ◽  
Bundle Adjustment ◽  
Controlled Environment ◽  
Calibration Model ◽  
Iterative Approach ◽  
Virtual Image ◽  
Advantages And Disadvantages ◽  
Novel Approach ◽  
Calibration Models

Abstract. Obtaining accurate image interior and exterior orientations is the key to improve 3D measurement accuracy besides reliable and accurate image matching. A majority of cameras used for those tasks are non-metric cameras. Non-metric cameras commonly suffer various distortions. Generally, there are two ways to remove these distortions: 1) conducting prior camera calibration in a controlled environment; 2) applying self-calibrating bundle adjustment in the application environment. Both approaches have their advantages and disadvantages but one thing is common that there is no universal calibration model available so far which can remove all sorts of distortions on images and systemic errors of image orientations. Instead of developing additional calibration models for camera calibration and self-calibrating adjustment, this paper presents a novel approach which applies self-calibrating bundle adjustment in an iterative fashion: after performing a conventional self-calibrating bundle adjustment, the image coordinates of tie points are re-calculated using the newly obtained self-calibration model coefficients, and the self-calibrating bundle adjustment is applied again in the hope that the remaining distortions and systematic errors will be reduced further within next a few iterations. Using a “virtual image” concept this iterative approach does not require to resample images or/and re-measure tie points during iterations, only costs a few additional iterations computational resource. Several trails under various application environments are conducted using this proposed iterative approach and the results indicate that not only the distortions can be reduced further but also image orientations become much stable after a few iterations.

Review of classification studies for machine learning in the development of intelligent management decision support systems

2020 ◽  
Vol 89 ◽  
pp. 20-29
Author(s):  
Sh. K. Kadiev ◽  
◽  
R. Sh. Khabibulin ◽  
P. P. Godlevskiy ◽  
V. L. Semikov ◽  
...  
Keyword(s):  
Machine Learning ◽  
Decision Support ◽  
Mathematical Models ◽  
Decision Support Systems ◽  
Support Systems ◽  
Management Decision ◽  
Classification Methods ◽  
Advantages And Disadvantages ◽  
Intelligent Management ◽  
Management Decision Support

Introduction. An overview of research in the field of classification as a method of machine learning is given. Articles containing mathematical models and algorithms for classification were selected. The use of classification in intelligent management decision support systems in various subject areas is also relevant. Goal and objectives. The purpose of the study is to analyze papers on the classification as a machine learning method. To achieve the objective, it is necessary to solve the following tasks: 1) to identify the most used classification methods in machine learning; 2) to highlight the advantages and disadvantages of each of the selected methods; 3) to analyze the possibility of using classification methods in intelligent systems to support management decisions to solve issues of forecasting, prevention and elimination of emergencies. Methods. To obtain the results, general scientific and special methods of scientific knowledge were used - analysis, synthesis, generalization, as well as the classification method. Results and discussion thereof. According to the results of the analysis, studies with a mathematical formulation and the availability of software developments were identified. The issues of classification in the implementation of machine learning in the development of intelligent decision support systems are considered. Conclusion. The analysis revealed that enough algorithms were used to perform the classification while sorting the acquired knowledge within the subject area. The implementation of an accurate classification is one of the fundamental problems in the development of management decision support systems, including for fire and emergency prevention and response. Timely and effective decision by officials of operational shifts for the disaster management is also relevant. Key words: decision support, analysis, classification, machine learning, algorithm, mathematical models.

scholarly journals Effectiveness of Variable-Gain Kalman Filter Based on Angle Error Calculated from Acceleration Signals in Lower Limb Angle Measurement with Inertial Sensors

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Yuta Teruyama ◽  
Takashi Watanabe
Keyword(s):  
Kalman Filter ◽  
Lower Limb ◽  
Measurement Accuracy ◽  
Inertial Sensors ◽  
Angle Measurement ◽  
Angle Error ◽  
Variable Gain ◽  
Improve Measurement ◽  
Kalman Gain ◽  
Acceleration Signals

The wearable sensor system developed by our group, which measured lower limb angles using Kalman-filtering-based method, was suggested to be useful in evaluation of gait function for rehabilitation support. However, it was expected to reduce variations of measurement errors. In this paper, a variable-Kalman-gain method based on angle error that was calculated from acceleration signals was proposed to improve measurement accuracy. The proposed method was tested comparing to fixed-gain Kalman filter and a variable-Kalman-gain method that was based on acceleration magnitude used in previous studies. First, in angle measurement in treadmill walking, the proposed method measured lower limb angles with the highest measurement accuracy and improved significantly foot inclination angle measurement, while it improved slightly shank and thigh inclination angles. The variable-gain method based on acceleration magnitude was not effective for our Kalman filter system. Then, in angle measurement of a rigid body model, it was shown that the proposed method had measurement accuracy similar to or higher than results seen in other studies that used markers of camera-based motion measurement system fixing on a rigid plate together with a sensor or on the sensor directly. The proposed method was found to be effective in angle measurement with inertial sensors.

Analysis of the Test Method of Quartz Glass Optical Homogeneity

2017 ◽  
Vol 726 ◽  
pp. 414-418
Author(s):  
Bo Fu ◽  
Hui Wang ◽  
Zhu Feng Shao
Keyword(s):  
Quartz Glass ◽  
Measurement Accuracy ◽  
Test Methods ◽  
Test Method ◽  
Wavefront Aberration ◽  
Optical Homogeneity ◽  
Advantages And Disadvantages ◽  
Interference Measurement ◽  
Optical Quartz Glass

The optical quartz glass is widely applied in optical system , photo communications，inertial navigation，etc.It must have high optical homogeneity. Optical homogeneity of the optical quartz glass directly affects the wavefront quality of the optical transmission system, and changes the wavefront aberration of the system. How to accurately determine the optical homogeneity of the quartz glass is especially important. Currently，the method of test for optical homogeneity mainly used by interference principle. This paper analyzes various existing interference measurement method and test equipment. Summarized the advantages and disadvantages of various test methods，using range and measurement accuracy.

scholarly journals A Novel Vision-Based Pose Measurement Method Considering the Refraction of Light

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4348 ◽  
Author(s):  
Wei Liu ◽  
Xin Ma ◽  
Xiao Li ◽  
Yi Pan ◽  
Fuji Wang ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Measurement Accuracy ◽  
Performance Testing ◽  
Angle Measurement ◽  
Normal Vector ◽  
Calibration Model ◽  
Linear Calibration ◽  
Observation Window ◽  
Vision Measurement

Nowadays, due to the advantages of non-contact and high-speed, vision-based pose measurements have been widely used for aircraft performance testing in a wind tunnel. However, usually glass ports are used to protect cameras against the high-speed airflow influence, which will lead to a big measurement error. In this paper, to further improve the vision-based pose measurement accuracy, an imaging model which considers the refraction light of the observation window was proposed. In this method, a nonlinear camera calibration model considering the refraction brought by the wind tunnel observation window, was established first. What’s more, a new method for the linear calibration of the normal vector of the glass observation window was presented. Then, combining with the proposed matching method based on coplanarity constraint, the six pose parameters of the falling target could be calculated. Finally, the experimental setup was established to conduct the pose measurement study in the laboratory, and the results satisfied the application requirements. Besides, experiments for verifying the vision measurement accuracy were also performed, and the results indicated that the displacement and angle measurement accuracy approximately increased by 57% and 33.6%, respectively, which showed the high accuracy of the proposed method.

Research on Data Aggregation Algorithms Based on OPT in Wireless Sensor Networks

2013 ◽  
Vol 427-429 ◽  
pp. 1991-1994
Author(s):  
Xue Wen He ◽  
Le Ping Zheng ◽  
Kuan Gang Fan ◽  
Sun Han ◽  
Qing Mei Cao
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Data Aggregation ◽  
Measurement Accuracy ◽  
Wireless Sensor ◽  
Data Traffic ◽  
Fusion Model ◽  
Design Goal ◽  
Improve Measurement ◽  
Battery Energy

Since wireless sensor networks consist of sensors with limited battery energy, a major design goal is to maximize the lifetime of sensor network. To improve measurement accuracy and prolong network lifetime, reducing data traffic is needed. In the clustering-based wireless sensor networks, a novel data aggregation algorithm based on OPT and Layida Method is proposed. In the proposed method, Layida Method preprocesses data and data fusion model for data integration are used. Its availability is proved by comparing with the results of two existing algorithms.

scholarly journals Construction and calibration of TDR probes for volumetric water content estimation in a Distroferric Red Latosol

2013 ◽  
Vol 33 (5) ◽  
pp. 919-928 ◽  
Author(s):  
Rosimaldo Soncela ◽  
Silvio C. Sampaio ◽  
Marcio A. Vilas Boas ◽  
Maria H. F. Tavares ◽  
Adriana Smanhotto
Keyword(s):  
Water Content ◽  
Irrigation Management ◽  
Time Domain Reflectometry ◽  
Volumetric Water Content ◽  
Coefficient Of Determination ◽  
Calibration Model ◽  
Advantages And Disadvantages ◽  
Disturbed Soil ◽  
Red Latosol ◽  
The Time Domain

The determination of volumetric water content of soils is an important factor in irrigation management. Among the indirect methods for estimating, the time-domain reflectometry (TDR) technique has received a significant attention. Like any other technique, it has advantages and disadvantages, but its greatest disadvantage is the need of calibration and high cost of acquisition. The main goal of this study was to establish a calibration model for the TDR equipment, Trase System Model 6050X1, to estimate the volumetric water content in a Distroferric Red Latosol. The calibration was carried out in a laboratory with disturbed soil samples under study, packed in PVC columns of a volume of 0.0078m³. The TDR probes were handcrafted with three rods and 0.20m long. They were vertically installed in soil columns, with a total of five probes per column and sixteen columns. The weightings were carried out in a digital scale, while daily readings of dielectric constant were obtained in TDR equipment. The linear model θν = 0.0103 Ka + 0.1900 to estimate the studied volumetric water content showed an excellent coefficient of determination (0.93), enabling the use of probes in indirect estimation of soil moisture.

scholarly journals World Experience in Creating Mathematical Models of Air Springs: Advantages and Disadvantages

2021 ◽  
pp. 25-42
Author(s):  
A. Y Kuzyshyn ◽  
S. A Kostritsia ◽  
Yu. H Sobolevska ◽  
А. V Batih
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Mathematical Models ◽  
Dynamic Behavior ◽  
High Speed ◽  
Vertical Direction ◽  
Rolling Stock ◽  
Air Spring ◽  
Advantages And Disadvantages ◽  
Mechanical Models

Purpose. Taking into account the production and commissioning of modern high-speed rolling stock, the authors are aimed to analyze the currently created mathematical models describing the dynamic behavior of the air spring, systematize them and consider the advantages and disadvantages of each model type. Methodology. For the analysis, a comparative chronological method was used, which makes it possible to trace the development of several points of view, concepts, theories. In accordance with the adopted decision equations, the existing models of air springs were divided into three groups: mechanical, thermodynamic and finite-elements. When analyzing mathematical models, the influence of a number of parameters on the dynamic behavior of the air spring, such as disturbing force frequency, heat transfer, nonlinear characteristics of materials, the shape of the membrane, etc., was considered. Findings. A feature of mechanical models is the determination of input parameters based on the analysis of experimental results, requires access to complex measuring equipment and must be performed for each new model of an air spring separately. Unlike mechanical models, which allow taking into account the damping effect of an air spring in the horizontal and vertical direction, thermodynamic models are mainly focused on studying the dynamic behavior of an air spring in the vertical direction. The use of the finite element method makes it possible to most accurately reproduce the dynamic behavior of an air spring, however, it requires significant expenditures of time and effort to create a finite element model and perform calculations. Originality. Mathematical models of the dynamic behavior of an air spring are systematized, and the importance of their study in conjunction with a spatial mathematical model of high-speed rolling stock is emphasized. Practical value. The analysis of the mathematical models of the dynamic behavior of the air spring shows the ways of their further improvement, indicates the possibility of their use in the spatial mathematical model of the rolling stock in accordance with the tasks set. It will allow, even at the design stage of high-speed rolling stock, to evaluate its dynamic characteristic and traffic safety indicators when interacting with a railway track.

scholarly journals Modelos alométricos na determinação da área foliar de Bauhinia monandra Kurz

2016 ◽  
Vol 7 (3) ◽  
pp. 415
Author(s):  
Edilson Romais Schmildt ◽  
Omar Schmildt ◽  
Rodrigo Sobreira Alexandre ◽  
Adriano Alves Fernandes ◽  
Marcio Paulo Czepak
Keyword(s):  
Mathematical Models ◽  
Leaf Area ◽  
Linear Model ◽  
Potential Model ◽  
Leaf Surface ◽  
Linear Quadratic ◽  
Potential Models ◽  
Independent Variables ◽  
Model Based ◽  
Area Determination

The aim of this study was to evaluate the efficiency of the adjustment of mathematical models for determining Bauhinia monandra leaf area using the length and/or width of the leaves as independent variables. Leaves from plants with three years were used to the estimative of equations in linear, quadratic and potential models. The validation from the estimated leaf area as a function of the observed leaf area showed that the linear model based on the product of length and width of the largest leaf surface is the model that best fits. However, the leaf area determination can be represented by using only the length or width of the leaves with little loss of accuracy. A representation that better estimates Bauhinia monandra leaf area with easy application is the potential model in which xi represents the length of one of the symmetrical leaf lobes.

Math Modeling of Vacuum Conductive Timber Drying

2014 ◽  
Vol 1040 ◽  
pp. 478-483
Author(s):  
M. Goreshnev ◽  
E. Litvishko
Keyword(s):  
Mathematical Modeling ◽  
Mass Transfer ◽  
Mathematical Models ◽  
Heat And Mass Transfer ◽  
Block Diagram ◽  
Calculated Data ◽  
Math Modeling ◽  
Advantages And Disadvantages ◽  
Transfer Problems

The article is devoted to the mathematical modeling of vacuum conductive timber drying. Analysis of known mathematical models allowed revealing their advantages and disadvantages. The modeling block diagram based on the drying periods is proposed. Lykov’s equations have been selected to solve heat and mass transfer problems. The comparison of experimental and calculated data has been conducted.

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