scholarly journals Measurement accuracy and uncertainty in plant biomechanics

2019 ◽  
Vol 70 (14) ◽  
pp. 3649-3658 ◽  
Author(s):  
Nathanael Nelson ◽  
Christopher J Stubbs ◽  
Ryan Larson ◽  
Douglas D Cook

AbstractAll scientific measurements are affected to some degree by both systematic and random errors. The quantification of these errors supports correct interpretation of data, thus supporting scientific progress. Absence of information regarding reliability and accuracy can slow scientific progress, and can lead to a reproducibility crisis. Here we consider both measurement theory and plant biomechanics literature. Drawing from measurement theory literature, we review techniques for assessing both the accuracy and uncertainty of a measurement process. In our survey of plant biomechanics literature, we found that direct assessment of measurement accuracy and uncertainty is not yet common. The advantages and disadvantages of efforts to quantify measurement accuracy and uncertainty are discussed. We conclude with recommended best practices for improving the scientific rigor in plant biomechanics through attention to the issues of measurement accuracy and uncertainty.

1978 ◽  
Vol 48 ◽  
pp. 7-29
Author(s):  
T. E. Lutz

This review paper deals with the use of statistical methods to evaluate systematic and random errors associated with trigonometric parallaxes. First, systematic errors which arise when using trigonometric parallaxes to calibrate luminosity systems are discussed. Next, determination of the external errors of parallax measurement are reviewed. Observatory corrections are discussed. Schilt’s point, that as the causes of these systematic differences between observatories are not known the computed corrections can not be applied appropriately, is emphasized. However, modern parallax work is sufficiently accurate that it is necessary to determine observatory corrections if full use is to be made of the potential precision of the data. To this end, it is suggested that a prior experimental design is required. Past experience has shown that accidental overlap of observing programs will not suffice to determine observatory corrections which are meaningful.


2017 ◽  
Vol 726 ◽  
pp. 414-418
Author(s):  
Bo Fu ◽  
Hui Wang ◽  
Zhu Feng Shao

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.


2021 ◽  
Vol 11 (14) ◽  
pp. 6390
Author(s):  
Marcin Maciejewski

The paper presents the research of the SteamVR tracker developed for a man-portable air-defence training system. The tests were carried out in laboratory conditions, with the tracker placed on the launcher model along with elements ensuring the faithful reproduction of operational conditions. During the measurements, the static tracker was moved and rotated in a working area. The range of translations and rotations corresponded to the typical requirements of a shooting simulator application. The results containing the registered position and orientation values were plotted on 3D charts which showed the tracker’s operation. Further analyses determined the values of the systematic and random errors for measurements of the SteamVR system operating with a custom-made tracker. The obtained results with random errors of 0.15 mm and 0.008° for position and orientation, respectively, proved the high precision of the measurements.


2015 ◽  
Vol 77 ◽  
pp. 1-7 ◽  
Author(s):  
Q. Lin ◽  
S.J. Neethling ◽  
K.J. Dobson ◽  
L. Courtois ◽  
P.D. Lee

2021 ◽  
Author(s):  
Majed Nahed Alrabeh ◽  
Zulkiflie Bin Samsudine ◽  
Salvador Alejandro Ruvalcaba Velarde ◽  
Faisal Mohammed Alhajri

Abstract The objective of this paper is to present the findings obtained from a detailed engineering evaluation resulting from trial testing two state-of-the-art surface horizontal pumping systems (HPS's) in two water supply wells. The two horizontal pumping systems were deployed as an alternative to downhole electrical submersible pumps (ESPs) to provide the benefits of eliminating ESP workover costs, modularity regarding wellsite deployments, and enhanced maintenance operations. For this trial test evaluation method, two HPS's were deployed to boost water production to the water injection plant (WIP). To ensure a thorough evaluation, the trial test well candidates were designed to accommodate both a subsurface ESP as well as a surface HPS to provide an accurate comparison, and representation, between the different artificial lift methods. The trial test and comparison method described in this paper focused primarily on the following items; maintenance and well intervention requirements, evaluation of operational availability, including potential for cavitation and effects of interference, maximum production rates, as well as root cause engineering evaluations for mechanical seals and cooling unit auxiliary motors. Various best practices and mitigation measures were identified and are presented in this paper. With regard to the results, it was observed that each artificial lift method comprised a set of advantages and disadvantages. The decision on which type of technology to use can be dependent on several factors. Overall, the HPS's demonstrated the ability to supply water production to the WIP. The HPS did experience operational challenges in providing higher production requirements. Additional challenges were also observed in the sealing mechanism as well as the auxiliary cooling unit. Precautionary pump tripping automated protocols were taken to prevent pump cavitation due to sub-optimal intake pressure resulting from possible interference. The HPS, unlike the ESPs, did not require any workover as it is located at the wellsite and therefore resulted in substantial cost savings and was easy to maintain due to its surface application. In summary, this paper adds a new and very beneficial evaluation of HPS's, and highlights best practices and lessons learned to the existing body of literature. The new information discussed in this paper is highly beneficial to engineering selections of artificial lift methods and to the successful implementation of HPS's in the industry.


Author(s):  
Reena Agrawal ◽  
Ganga Bhavani

Corporate governance is a significant tool to build strong and long relationships among various stakeholders in kinds of business organizations. Family businesses are not an exception to this. Like any other businesses, family businesses also need to have governance in place and practice to achieve the business strategies and to have long-term succession. Family-owned businesses are the backbone of many countries' economies in the world contributing substantial portion of GDP. Considering these, it is important to know the best practices of governance in family owned business organizations and the role played by governance to improve the strengths of these businesses. The chapter throws light on family business governance and explores various important practices highlighting their advantages and disadvantages in detail.


Author(s):  
Patrick Suppes

A conceptual analysis of measurement can properly begin by formulating the two fundamental problems of any measurement procedure. The first problem is that of representation, justifying the assignment of numbers to objects or phenomena. We cannot literally take a number in our hands and ’apply’ it to a physical object. What we can show is that the structure of a set of phenomena under certain empirical operations and relations is the same as the structure of some set of numbers under corresponding arithmetical operations and relations. Solution of the representation problem for a theory of measurement does not completely lay bare the structure of the theory, for there is often a formal difference between the kind of assignment of numbers arising from different procedures of measurement. This is the second fundamental problem, determining the scale type of a given procedure. Counting is an example of an absolute scale. The number of members of a given collection of objects is determined uniquely. In contrast, the measurement of mass or weight is an example of a ratio scale. An empirical procedure for measuring mass does not determine the unit of mass. The measurement of temperature is an example of an interval scale. The empirical procedure of measuring temperature by use of a thermometer determines neither a unit nor an origin. In this sort of measurement the ratio of any two intervals is independent of the unit and zero point of measurement. Still another type of scale is one which is arbitrary except for order. Moh’s hardness scale, according to which minerals are ranked in regard to hardness as determined by a scratch test, and the Beaufort wind scale, whereby the strength of a wind is classified as calm, light air, light breeze, and so on, are examples of ordinal scales. A distinction is made between those scales of measurement which are fundamental and those which are derived. A derived scale presupposes and uses the numerical results of at least one other scale. In contrast, a fundamental scale does not depend on others. Another common distinction is that between extensive and intensive quantities or scales. For extensive quantities like mass or distance an empirical operation of combination can be given which has the structural properties of the numerical operation of addition. Intensive quantities do not have such an operation; typical examples are temperature and cardinal utility. A widespread complaint about this classical foundation of measurement is that it takes too little account of the analysis of variability in the quantity measured. One important source is systematic variability in the empirical properties of the object being measured. Another source lies not in the object but in the procedures of measurement being used. There are also random errors which can arise from variability in the object, the procedures or the conditions surrounding the observations.


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