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"Units of measurement."
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The seven measures of the world
\"From the beginning of history, measurement has been interwoven into the human experience, shaping our understanding of nature, personal relationships, and the supernatural. We measure the world to know our past, comprehend the present, and plan the future. Renowned physicist Piero Martin explores how scientific knowledge is built around seven key pillars of measurement: the meter for length; the second for time; the kilogram for mass; the kelvin for temperature; the ampere for electricity; the mole for quantity of substance; and the candela for luminous intensity. Martin examines the history and function of these units and illustrates their applications in rich vignettes on a range of topics--from quarks to black holes, from a glass of wine to space exploration. He delves into not only the all-important numbers but also anecdotes that underline each unit's special quality. At the same time, he explains how each unit contributes to important aspects of science, from classical physics to quantum mechanics, from relativity to chemistry, from cosmology to elementary particle physics, and from medicine to modern technology. Martin eloquently shows how the entire universe can be measured and understood using just seven units.\"--Dust jacket.
Book
Development and strategy of reference materials for the DNA-based detection of genetically modified organisms
The enforcement of GMO labeling regulations requires validated analytical methods and certified reference materials (CRMs). The early labeling regulations stipulated that the GMO content should be expressed as percentage, but did not specify what unit this percentage referred to. Two reference systems, using mass fraction and copy number ratio as measurement units, individually, are established for GMO analysis using different metrological traceability chains. Three types of CRMs, powder CRMs certified for mass fractions, genomic DNA CRMs, and plasmid DNA CRMs certified for copy number ratios, were developed for calibration and quality control. The type, certification, and measurement unit commutability of current GMO CRMs are presented and discussed in this paper. Both existing reference systems are facing a metrological challenge, although later EU regulations specified that the measurement unit of GMO content must be expressed in mass fraction and recommended to convert one unit into another by introducing a conversion factor, further efforts are required to explore which reference system is more metrologically sound. The determination of conversion factor per CRM batch is recommended to be based on the pure CRMs produced from pure GM materials, which is expected to be the best choice for calibration of PCR measurement results.
Journal Article
Get the measure : units and measurements
\"Introduces the reader to measurements.\"-- Provided by publisher.
Book
Quantitative analysis of the bilateral coordination and gait asymmetry using inertial measurement unit-based gait analysis
Inertial measurement unit (IMU)-based gait analysis can be used to quantitatively analyze the bilateral coordination and gait asymmetry (GA). The purpose of this study was to investigate changes in bilateral coordination and GA due to gait speed using an IMU based gait analysis and identify spatiotemporal factors affecting bilateral coordination and GA. Eighty healthy adults (40 men and 40 women) participated in the study. The mean age was 26.2 years, and the mean body mass index was 22.8 kg/m2. Three different walking speeds (80%, 100%, and 120% of preferred walking speed) on a treadmill were applied for 1 min of continuous level walking using a shoe-type IMU-based gait analysis system. The phase coordination index (PCI) and GA were calculated on three different walking speeds. Several variables (gait speed, height, body mass index, cadence, and step length) were analyzed as possible factors affecting the PCI and GA. Bilateral coordination and GA improved during fast walking (p = 0.005 and p = 0.019, respectively) and deteriorated during slow walking (p<0.001 and p = 0.008, respectively), compared with the participants' preferred walking speeds. The correlation analysis revealed that PCI was negatively correlated with step length at each walking condition and lower gait speed was negatively correlated with PCI and GA during slow walking. Both bilateral coordination and GA had a negative linear relationship with gait speed, showing an improvement in the fast walking condition and deterioration in the slow walking condition. Step length was the factor associated with the change in the bilateral coordination.
Journal Article
Using measuring cups
Presents information about measuring containers scientists use for their own science experiments.
Book
A scalable semantic data fusion framework for heterogeneous sensors data
Data fusion is a fundamental research topic especially in the Internet of Things (IoT). A massive quantity of data is increasingly being generated by heterogeneous sensors which make data integration more difficult. A noticeable body of research has attempted to mitigate the incompatibility between the collected data to facilitate meaningful data integration between machines by using the semantic web technologies. However, there are still some critical issues including scalability and measurement unit conflicts. Therefore, this paper proposes a scalable semantic data fusion framework that aims at improving the scalability of data fusion and detecting and reconciling measurement unit conflicts. This framework is fully implemented to demonstrate its scalability during the process of data fusion, and its ability to handle measurement unit conflicts. Two experiments were conducted to evaluate the scalability and effectiveness of the proposed framework using real dataset that was collected from different sensors. To evaluate the scalability of the proposed framework, a set of queries was adapted and the average response time was calculated from the execution of every query. Whereas, the total number of the conflicts detected and resolved by the proposed framework were used to evaluate the effectiveness. Experimental results show that the proposed framework improves the scalability of data fusion among heterogeneous sensors’ data, and effective in detecting and resolving data unit conflicts.
Journal Article
I'm longer than you! : an epic contest of measurement
\"When Blue Whale and Supersaurus hold a contest to see who is longest, desperate measures are called for (or any measures!). Enter Inchworm, who offers to measure them each from tip to tail to determine the winner. Inchworm measures Blue Whale in inches, but has to leave early to prepare for its cocoon. Enter Centipede, who meaures Supersaurus in centimeters. But with one measurement in inches and the other in centimeters, how will they ever figure out who is longest? And more important, who will win the free lunch? Funny, smart and delightfully original, this informational picture book explores measurement for young readers. Back matter includes more information about the animals and plants in the book and additional content about other units of measure.\"-- Provided by publisher.
CHILDBOOK
Vector Expression of Units of Physical Quantities
Vector representations of physical quantities in pseudo-Euclidean space are used to discuss several options for an appropriate coordinate system used to express a system of units. The SI system is found to have several issues causing the system of units to be overdetermined and underdetermined. We propose a version of the SI system that takes into account the three-dimensional nature of physical space and eliminates “dimensional isotopes,” i.e., quantities with different physical meaning but identical dimensions in the SI system. We demonstrate that the mathematical expression for the vector norm of a measurement unit, referred to as a “system unit,” can be used to determine whether a unit is within the range of variation in such a system unit.
Journal Article
rKIN
The isotopic niche of consumers represents biologically relevant information on resource and habitat use. Several tools have been developed to quantify niche size and overlap. Nonetheless, methods adapted by spatial ecologists to quantify animal home ranges can be modified for use in stable isotope ecology when data are not normally distributed in bivariate space. We offer a tool that draws on existing spatial metrics, such as minimum convex polygon (MCP) and standard ellipse area (SEA), and add novel metrics using kernel utilization density (KUD) estimators to measure isotopic niche size and overlap. We present examples using empirical and simulated data to demonstrate the performance of the package kernel isotopic niches in r (rKIN) under various scenarios. Results of niche size from MCP, SEA and KUD were highly correlated but divergent among datasets. Overall, the KUD method produced the largest niche sizes and was more sensitive to the distribution of the isotopic data. Pairwise estimates of overlap were highly variable, likely because MCP and SEA inherently include or exclude unused areas in the resulting niche estimate. Four bandwidth methods (reference, normal scale, plug‐in and biased cross‐validation) produced comparable estimates of niche size and overlap at various sample sizes (10–40). Niche size and overlap were consistent across sample sizes >15. Use of rKIN will allow isotope ecologists to quantify niche shifts, expansions or contractions, as well as assess the performance of several estimation methods. The package also can be applied to other data types (e.g. principal component analysis, multi‐dimensional scaling) so long as axes and measurement units are identical and can be converted to Cartesian coordinates. The authors offer a tool that draws on existing spatial metrics, such as minimum convex polygon and standard ellipse area, and add novel metrics using kernel utilization density estimators to measure isotopic niche size and overlap. rKIN will allow isotope ecologists to quantify niche shifts, expansions or contractions.
Journal Article
Research on high-precision measurement technology for aircraft large-scale tooling assembly
With the trend of aircraft component assembly moving towards integration, large size, and high precision, more stringent requirements are being placed on assembly fixtures. This paper conducts a technical study on high-precision measurement techniques for large-scale aircraft assembly tooling. It analyzes the measurement error of points based on laser trackers and the error of changing stations in the measurement unit. By locally establishing a networked measurement system composed of laser trackers to form a measurement unit, an optimized multi-lateral measurement algorithm is adopted to calibrate the reference. The calibration accuracy of the reference as a whole is improved through a ring-closed global optimization algorithm, establishing a global measurement coordinate system. The precision of the large-scale measurement field is verified through experiments, and based on this, a method for constructing the measurement field for large-scale assembly fixtures is analyzed and summarized.
Journal Article