A comprehensive error model for polarimetric measurement systems

2002 ◽  
Author(s):  
H. Bouzari ◽  
A. Tavaksli ◽  
H. Heydar
Keyword(s):  
Error Model ◽  
Measurement Systems ◽  
Comprehensive Error Model

scholarly journals Enhancing machining accuracy reliability of multi-axis CNC machine tools using an advanced importance sampling method

2021 ◽  
Vol 23 (3) ◽  
pp. 559-568
Author(s):  
Zhiming Wang ◽  
Hao Yuan
Keyword(s):  
Importance Sampling ◽  
Machine Tools ◽  
Sampling Method ◽  
Great Influence ◽  
Error Model ◽  
Cnc Machine Tools ◽  
Machining Accuracy ◽  
Cnc Machine ◽  
Importance Sampling Method ◽  
Comprehensive Error Model

The purpose of this paper is to propose a general precision allocation method to improve machining performance of CNC machine tools based on certain design requirements. A comprehensive error model of machine tools is established by using the differential motion relation of coordinate frames. Based on the comprehensive error model, a reliability model is established by updating the primary reliability with an advanced importance sampling method, which is used to predict the machining accuracy reliability of machine tools. Besides, to identify and optimize geometric error parameters which have a great influence on machining accuracy reliability of machine tools, the sensitivity analysis of machining accuracy is carried out by improved first-order second-moment method. Taking a large CNC gantry guide rail grinder as an example, the optimization results show that the method is effective and can realize reliability optimization of machining accuracy.

Food Safety Security: A new Concept for Enhancing Food Safety Measures

2012 ◽  
Vol 82 (3) ◽  
pp. 216-222 ◽  
Author(s):  
Venkatesh Iyengar ◽  
Ibrahim Elmadfa
Keyword(s):  
Food Safety ◽  
Hazard Analysis ◽  
Warning System ◽  
Shared Responsibility ◽  
Fine Tuning ◽  
Strategic Action ◽  
Surveillance Network ◽  
Measurement Systems ◽  
Critical Control Points ◽  
The Impact

The food safety security (FSS) concept is perceived as an early warning system for minimizing food safety (FS) breaches, and it functions in conjunction with existing FS measures. Essentially, the function of FS and FSS measures can be visualized in two parts: (i) the FS preventive measures as actions taken at the stem level, and (ii) the FSS interventions as actions taken at the root level, to enhance the impact of the implemented safety steps. In practice, along with FS, FSS also draws its support from (i) legislative directives and regulatory measures for enforcing verifiable, timely, and effective compliance; (ii) measurement systems in place for sustained quality assurance; and (iii) shared responsibility to ensure cohesion among all the stakeholders namely, policy makers, regulators, food producers, processors and distributors, and consumers. However, the functional framework of FSS differs from that of FS by way of: (i) retooling the vulnerable segments of the preventive features of existing FS measures; (ii) fine-tuning response systems to efficiently preempt the FS breaches; (iii) building a long-term nutrient and toxicant surveillance network based on validated measurement systems functioning in real time; (iv) focusing on crisp, clear, and correct communication that resonates among all the stakeholders; and (v) developing inter-disciplinary human resources to meet ever-increasing FS challenges. Important determinants of FSS include: (i) strengthening international dialogue for refining regulatory reforms and addressing emerging risks; (ii) developing innovative and strategic action points for intervention {in addition to Hazard Analysis and Critical Control Points (HACCP) procedures]; and (iii) introducing additional science-based tools such as metrology-based measurement systems.

Consumer Measurement Systems and Child and Adolescent Mental Health

1999 ◽  
Author(s):  
Leonard Bickman ◽  
Barry Nurcombe ◽  
Clare Townsend ◽  
Madge Belle ◽  
James Schut ◽  
...  
Keyword(s):  
Mental Health ◽  
Adolescent Mental Health ◽  
Child And Adolescent ◽  
Measurement Systems

Development and study of a method for cell separation during white blood cell segmentation on images of bone marrow preparations in information and measurement systems for diagnostics of acute leukemia

2020 ◽  
pp. 68-72
Author(s):  
V.G. Nikitaev ◽  
A.N. Pronichev ◽  
V.V. Dmitrieva ◽  
E.V. Polyakov ◽  
A.D. Samsonova ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Blood Cell ◽  
Acute Leukemia ◽  
White Blood Cell ◽  
Cell Separation ◽  
Large Scale ◽  
Bone Marrow Cells ◽  
Automated Analysis ◽  
Cell Segmentation ◽  
Measurement Systems

The issues of using of information and measurement systems based on processing of digital images of microscopic preparations for solving large-scale tasks of automating the diagnosis of acute leukemia are considered. The high density of leukocyte cells in the preparation (hypercellularity) is a feature of microscopic images of bone marrow preparations. It causes the proximity of cells to eachother and their contact with the formation of conglomerates. Measuring of the characteristics of bone marrow cells in such conditions leads to unacceptable errors (more than 50%). The work is devoted to segmentation of contiguous cells in images of bone marrow preparations. A method of cell separation during white blood cell segmentation on images of bone marrow preparations under conditions of hypercellularity of the preparation has been developed. The peculiarity of the proposed method is the use of an approach to segmentation of cell images based on the watershed method with markers. Key stages of the method: the formation of initial markers and builds the lines of watershed, a threshold binarization, shading inside the outline. The parameters of the separation of contiguous cells are determined. The experiment confirmed the effectiveness of the proposed method. The relative segmentation error was 5 %. The use of the proposed method in information and measurement systems of computer microscopy for automated analysis of bone marrow preparations will help to improve the accuracy of diagnosis of acute leukemia.

State special primary acceleration measurement standard for gravimetry GET 190-2019

2020 ◽  
pp. 3-8
Author(s):  
L.F. Vitushkin ◽  
F.F. Karpeshin ◽  
E.P. Krivtsov ◽  
P.P. Krolitsky ◽  
V.V. Nalivaev ◽  
...  
Keyword(s):  
High Precision ◽  
Free Fall ◽  
Measurement Range ◽  
Measurement Standard ◽  
Acceleration Measurement ◽  
Measurement Systems ◽  
Free Fall Acceleration ◽  
Investigation Methods ◽  
Measurement Results ◽  
Upper Level

The State special primary acceleration measurement standard for gravimetry (GET 190-2019), its composition, principle of operation and basic metrological characteristics are presented. This standard is on the upper level of reference for free-fall acceleration measurements. Its accuracy and reliability were improved as a result of optimisation of the adjustment procedures for measurement systems and its integration within the upgraded systems, units and modern hardware components. A special attention was given to adjusting the corrections applied to measurement results with respect to procedural, physical and technical limitations. The used investigation methods made it possibled to confirm the measurement range of GET 190-2019 and to determine the contributions of main sources of errors and the total value of these errors. The measurement characteristics and GET 90-2019 were confirmed by the results obtained from measurements of the absolute value of the free fall acceleration at the gravimetrical site “Lomonosov-1” and by their collation with the data of different dates obtained from measurements by high-precision foreign and domestic gravimeters. Topicality of such measurements ensues from the requirements to handle the applied problems that need data on parameters of the Earth gravitational field, to be adequately faced. Geophysics and navigation are the main fields of application for high-precision measurements in this field.

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