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Working with Data
Published in David E. Clough, Steven C. Chapra, Introduction to Engineering and Scientific Computing with Python, 2023
David E. Clough, Steven C. Chapra
Imagine we measure temperature with an instrument that provides a digital display with high resolution, 0.01°C. There is a natural temptation to presume that the measurements are “accurate” to the same extent. That is a mistake. Accuracy has to do with comparison to a standard of measurement. Standards of measurement are maintained by organizations such as the National Institute of Standards and Technology (NIST) in the U.S. and the Système International d’Unités (SI) in France. Secondary standards are calibrated against the primary NIST standards. Temperature instruments are generally accompanied with an accuracy specification. For our example above, that might be ± 0.1°C − ten times greater than the resolution. Many consider the term precision as a poor descriptor of data because it often refers to resolution, but it is easily confused with accuracy. Also, it may be confused with repeatability and dispersion. Figure 10.3 illustrates these concepts.
When the Physical Disorder of CMOS Meets Machine Learning
Published in Sumeet Walia, Krzysztof Iniewski, Low Power Semiconductor Devices and Processes for Emerging Applications in Communications, Computing, and Sensing, 2018
Xiaolin Xu, Shuo Li, Raghavan Kumar, Wayne Burleson
For security purposes, the responses from a PUF circuit must be unpredictable. Unpredictability is a measurement that quantifies the randomness of the responses from the same PUF device. This metric can be evaluated using the National Institute of Standards and Technology (NIST) tests [6,14]. Silicon PUFs produce unique responses based on intrinsic process variations, which are very difficult to clone or duplicate by the manufacturer. However, by measuring the responses from a PUF device for a subset of challenges, it is possible to create a model that can mimic the PUF under consideration. Several modeling attacks on PUF circuits have been proposed in the literature [15]. The type of modeling attack depends on the PUF circuit. A successful modeling attack on a PUF implementation may not be effective for other PUF implementations. Modeling attacks can be made more difficult by employing some control logic surrounding the PUF block, which prevents direct read-out of its responses. One such technique is to use a secure one-way hash over PUF responses. However, if PUF responses are noisy and have significant intra-distance, this technique will require some sort of error correction on PUF responses prior to hashing [8].
Essentials of Data Analytics
Published in Adedeji B. Badiru, Data Analytics, 2020
Evolution and standardization of measurement units often had interesting origins. For example, it was recorded that King Henry I decreed that a yard should be the distance from the tip of his nose to the end of his outstretched thumb. The length of a furlong (or furrow-long) was established by early Tudor rulers as 220 yards. This led Queen Elizabeth I to declare in the 16th century that the traditional Roman mile of 5,000 feet would be replaced by one of 5,280 feet, making the mile exactly eight furlongs and providing a convenient relationship between the furlong and the mile. To this day, there are 5,280 feet in one mile, which is 1,760 yards. Thus, through royal edicts, England, by the 18th century, had achieved a greater degree of standardization than other European countries. The English units were well suited to commerce and trade because they had been developed and refined to meet commercial needs. Through English colonization and its dominance of world commerce during the 17th, 18th, and l9th centuries, the English system of measurement units became established in many parts of the world, including the American colonies. The early 13 American colonies, however, had undesirable differences with respect to measurement standards for commerce. The need for a greater uniformity led to clauses in the Articles of Confederation (ratified by the original colonies in 1781) and the Constitution of the United States (ratified in 1788) that gave Congress the power to fix uniform standards for weights and measures across the colonies. Today, standards provided by the U.S. National Institute of Standards and Technology (NIST) ensure uniformity of measurement units throughout the country.
Pyrolysis of waste pomegranate peels for bio-oil production
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2018
The liquid product was characterized with the following various laboratory test techniques. The main physicochemical properties such as density, kinematic viscosity, and hydrocarbon distributions were tested. The liquid oil sample was analyzed using a GC-MS spectrophotometer according to the analysis procedure detailed. The fraction of decolorized atmospheric distillation was subjected to GC-MS analysis to determine its compound distributions. The analysis was carried out by Gas chromatography-mass spectrometry (GC-MS) (Agilent 6890 GC and 5973N Mass Selective Detector, Agilent Technologies, Santa Clara, CA), equipped with HP-INNOWax polyethylene glycol capillary column (60 m × 0.25 mm i.e., 0.25 μm). The program steps of oven temperature applied were firstly held for 10 min at an initial temperature of 60°C and then heated up to 150°C at a heating rate of 5°C/min and kept at this temperature for 20 min and lastly ramped to 250°C at the same rate and hold for 30 min at this final temperature. The compounds in the liquid product and also their relative concentrations (% area) were determined by the recorded data in the Nist08Wiley8.L, Nist05a.L and Flavor2.L of mass spectral libraries databases at the minimum quality of 85. The National Institute of Standards and Technology (Nist).
Automatically Solving Elementary Science Questions: A Survey
Published in IETE Technical Review, 2023
Swati Nagdev, Mansi A. Radke, Maya Ramanath
From the perspective of Information Retrieval, the growth and development of the QA systems has been rapid. To test a QA system, researchers need standardized evaluation techniques. Various performance metrics used for evaluating QA systems are as follows: BLEU (Bi-Lingual Evaluation Understudy) BLEU does not measure meaning. It rewards systems that have exact matches present in the corpus used.BLEU is based more on precision. Lack of recall is the main drawback of the BLEU metric.NIST metric (National Institute of Standards and Technology) NIST calculates how informative a particular N-gram is.Higher order N-grams are used which is an indirect measure for the translation level.METEOR (Metric for Evaluation of Translation with Explicit Ordering) METEOR metric is based on the harmonic mean of precision and recall of unigrams.ROUGE (Recall-Oriented Understudy for Gisting Evaluation) ROUGE is a set of metrics comprises ROUGE-L (Longest Common Subsequence), ROUGE-N (n-grams), ROUGE-S (skip-gram).ROUGE measures syntactical matches rather than the semantics.
Navy Metrology and Applications of Biosensors
Published in NCSLI Measure, 2018
Subrata Sanyal, Dylan Shackelford
Measurement traceability is an unbroken chain of calibrations to a verified standard and the documentation of the associated uncertainties. It is the series of steps upon which the current assigned value of measurement can be directly or indirectly compared to the value assigned as the U.S. national measurement standard or to natural physical constants, and the accuracies of such comparisons can be documented. NIST is responsible for developing, maintaining, and disseminating U.S. national measurement standards (realizations of the International System of units [SI]) for the basic and derived measurement quantities, and assessing the measurement uncertainties associated with these measurement standards. NIST works with other similar international organizations for metrological traceability to the SI. The highest echelon standards laboratory for the Department of the Navy is the Navy Primary Standards Lab (NPSL) [5]. The laboratory provides customers with over 4,000 calibrations each year. They service all Navy and Marine Corps calibration laboratories, and maintain measurement traceability to NIST. Figure 1 illustrates the hierarchy of Navy’s measurement traceability [6]. It is important to establish this form of traceability to understand the life cycle of the variety of parts and products used by the Navy, and to decide when to replace them. These measurement standards also apply to entities outside of the Navy. Having a national metrology agency such as NIST establish standards facilitates universal standardization; for example, it ensures that an inch as measured by one manufacturer coincides with that measured by another manufacturer of a different country. Therefore, during assembling such parts to manufacture any important sub-system or system, there is a greater level of confidence that the parts produced by different manufacturers are, in fact, compatible and fit together. Many important systems and parts are calibrated by Navy calibration labs and not by NIST because it is cost-prohibitive. However, the equipment used by the Navy to calibrate field systems is calibrated by NIST. The Navy’s calibration labs are used as another source of calibration standards for the smaller depot labs. These calibration standards have the measurement traceability to SI via the measurement standards kept at NPSL or at NIST. The Navy depot labs have trained technicians to carry out the required calibrations of Navy equipment using carefully written and detailed calibration procedures. This is done so that when the individual onboard a ship is asked to perform a calibration on, for example, a pressure gauge, there is no confusion as to how the procedure must be carried out.