Measurement Uncertainty

The practical implementation of an interpolation scheme for deriving the voltage reflection coefficients of short-circuit, open-circuit and matched load coaxial reflectometer calibration standards in the intermediate frequency (IF) range is described (where, broadly speaking, IF refers to the frequency range DC to 100 MHz). The scheme allows the use of commercially available devices (rather than specially constructed calculable devices) as

Stimulated by recent THz measurements of the methanol spectrum in one of our laboratories, undertaken in support of NASA programs related to the Herschel Space Observatory (HSO) and the Atacama Large Millimeter Array (ALMA), we have carried out a global analysis of available microwave and high-resolution infrared data for the first three torsional states (m t = 0, 1, 2), and for J values up to 30. This global fit of approximately 5600 frequency measurements and 19 000 Fourier transform far infrared (FTFIR) wavenumber measurements to 119 parameters reaches the estimated experimental measurement accuracy for the FTFIR transitions, and about twice the estimated experimental measurement accuracy for the microwave, submillimeter-wave, and terahertz transitions. The present fit is essentially a continuation of our earlier work, but we have greatly expanded our previous data set and have added a large number of new torsion-rotation interaction terms to the Hamiltonian in our previously used computer program. The results, together with a number of calculated (but unmeasured) transitions, including their line strength, estimated uncertainty, and lower state energy, are made available in the supplementary material as a database formatted to be useful for astronomical searches. Some discussion of several open spectroscopic problems, e.g., (i) an improved notation for the numerous parameters in the torsion-rotation Hamiltonian, (ii) possible causes of the failure to fit frequency measurements to the estimated measurement uncertainty, and (iii) pitfalls to be avoided when intercomparing apparently identical parameters from the internal axis method and the rho axis method are also given.

Cardiovascular diseases such as atherosclerosis are one of the leading causes of death in the developed world and associated monetary pressure on public health systems is considerable. The initiation and development of these diseases still remain poorly understood, but it is becoming increasingly identifiable as a dysfunction of the endothelia layer, which lines the arterial walls. The prevailing haemodynamic environment plays an important role in the development of atherosclerosis in specific regions of the human vasculature. Locally disturbed haemodynamics lead to very low wall shear stress and reduces convection of important blood borne chemicals to the arterial wall.

Tomographic Particle Image Velocimetry (TPIV) was used to study the initial transition process formed in a free jet between the laminar flow at the jet exit, and the fully turbulent flow region at Re=6500. The evolution of the turbulence characteristics in this particular region has been assessed by means of the invariants of the Velocity Gradient Tensor (VGT). These invariants enable us to study the dynamics, geometry and topology of the flow. A mapping from the three-dimensional flow fields to a two dimensional invariants plane is used to analyze the dissipation of kinetic energy at small scales and the amplification of local vorticity due to vortex stretching. A systematic study of the event that represents the persistent alignment of the vorticity vector with the second eigenvector of the rate of strain tensor was examined, and the results of this phenomenon at the near-field of the jet are discussed. Results show that vorticity vector, ω, maintains its alignment with the intermediate eigenvector of the rate of strain tensor, υ 2, in the developing region by either the rotation of the intermediate eigenframe or the tilting of ω.

In the present work we compare outdoor and indoor performance measurements of two sets of thin film large-area (> 1m 2 ) modules: 1) single-junction a-Si and 2) tandem a-Si/µc-Si. For the single-junction device, the indoor measurement with a pulsed solar simulator -after mismatch factor (MMF) correction -underestimates the P max by 3.3% compared to the outdoor measured P max (also MMF corrected), whereas for the tandem device the indoor measurements overestimates the P max by 4.9%. For the single-junction modules the discrepancy is within the measurement uncertainty of our measurement set-ups, whereas for tandem devices the discrepancy between indoor and outdoor slightly exceeds the calculated measurement uncertainty valid for standard devices. However, our calculation of measurement uncertainties did neither take sweep speed effects into account nor did it consider the uncertainties arising in the special case of tandem devices, due to current mismatch. Sweep-time measurements show the influence of the IV scan speed and direction on the measured FF, and therefore on P max . According to our results flashers with a pulse duration of 1.5 ms are not sufficient and at least 10 ms should be used to test these devices in a laboratory. The discrepancies in the measurement of short circuit current (I sc ) for both set of devices may originate from uncertainties in the calculation of the MMF correction. Moreover, for tandem devices the spectral mismatch correction is not yet standardized, but in one approach each junction is treated as a separate device. Although a larger temperature range is accepted for the outdoor performance measurement a relatively good match between indoor and outdoor measurements is obtained for V oc . These results will form the basis for the performance measurement of large-area multi-junction devices at ESTI and the development of a calibration procedure for tandem devices.

This article proposes a spectral method of assessing the dynamic uncertainty of measurement devices, that allows the investigation of the accuracy of measurement in dynamic operating conditions in the frequency domain and the evaluation of the amplitude values of dynamic uncertainty based on input signal frequency characteristics and spectral function. The results were tested when evaluating the dynamic uncertainty in measurements of the vibration acceleration of an engine. It was established that the maximum value of the dynamic uncertainty of the measurement of the vibration acceleration stands at 0.14 m/s 2 for an observation time of 300 s and with a nominal value of the signal of vibration acceleration of 2.34 m/s 2 at a frequency of 6 kHz, which in relative units is 6%.

Developed methodology for estimation of dynamic measurement uncertainty, which corresponds to the international standards for evaluating the quality of measurements -the concept of uncertainty. It is proposed to estimate the uncertainty of dynamic measurements on the basis of the frequency characteristic measuring means and the spectral function of the input signal. This method was tested in the evaluation of the dynamic measurement of vibration of rotating machines that helped confirm its correctness and efficiency. It is found that the maximum value of the dynamic uncertainty vibration acceleration measurement of 0,05 m/s 2 for an observation time of 300 s and the nominal value signal of vibration acceleration 0.35 m/s 2 at a frequency of 6 kHz.

The article discusses a new approach to the expression of dynamic uncertainty of experimental dynamic measurements based on a priori information about the frequency response measurement tool. This approach allows to measure the results of dynamic measurements with the international requirements for the characterization accuracy.

The development of evaluation methods for precision measurement and inter-verification interval measurement for measurement devices based on the concept of the uncertainty of measurement is needed in order to establish the timing of the next scheduled or unscheduled verification of the correspondence of metrological characteristics to their standardised values. The definition of the timing (periodicity) of the metrological verification of measurement devices as used in business or health care, while monitoring environmental conditions and proving health and safety at work, is an urgent issue in scientific research, upon which depends the quality of goods and services. A method of evaluating the accuracy of measurements and the inter-verification interval for measurement devices is proposed, based on using international standards guidelines for quality measurement. The calibration method for evaluating the inter-verification interval of measurement devices was tested during the metrological certification of the measurement device for the moment of inertia of electric motors.

Evaluating measurement uncertainty of a physical quantity is a mandatory requirement for laboratories within the recognition ISO/IEC 17025 certification to access reliability of measured results. In this work, the uncertainty of ionizing radiation measurements such as air-kerma, personal dose equivalent Hp(d) was evaluated based on GUM method and Monte Carlo method. An uncertainty propagation software has been developed for evaluation of the measurement uncertainty more convenient.

The paper proposes and metrologically characterizes a gap and flushness optical measurement system based on machine vision. The system is developed for an operator-free application as a plugand-play feature for articulated robotic arms. The system is designed for use in Stop-and-Go quality control point of vehicle assembly process. Non-contact measurement system that consists of an ultraviolet line laser with a sensitive camera and complemented with an advanced machine vision measurement algorithm is developed. The system is directly calibrated according to state-of-the-art literature and the measurement uncertainty within the laboratory conditions is derived according to Guide to the Expression of Uncertainty in Measurement. Measurements on the real vehicle body is done to elicit the difference. The expanded uncertainty achieved by the system is 0.221 mm and 0.177 mm for gap and flushness respectively, significantly smaller than the sole resolution of the most adopted manual feeler gauge verification method. INDEX TERMS Gap and flushness, non-contact measurement, line laser system, camera calibration, machine vision, body-in-white.

Abstract. The purpose of this paper is to address the strategic and tactic issues in agent communication. Strategic reasoning enables agents to decide about the global communication plan in terms of the macro-actions to perform in order to achieve the main conversational ...

Determination of the solar cell efficiency and internal quantum efficiency are standard characterization methods used by the majority of research institutes. Random errors can be assessed by institutes themselves by repeated measurements, but systematic deviations cannot be assessed without comparisons with other institutes. The comparisons were performed for illuminated IV, spectral response and reflection measurements. The results were split into systematic differences between the partners and random differences within an institute for a single measurement session. The total differences are: Jsc: 0.27 A, Voc: 8.5 mV, FF: 2.4 %, η: 0.6%, spectral response: 0.14 A/W and reflection: 0.08. For all measurement methods, the systematic differences exceeded the random differences. The major component for the systematic differences is likely the reference device, but also temperature control, contacting scheme and setup differences play a part.

Starting from a critical analysis of recently reported surprisingly large uncertainties in length and position measurements deduced within the framework of quantum gravity, we embark on an investigation both of the correlation structure of Planck scale fluctuations and the role the holographic hypothesis is possibly playing in this context. While we prove the logical independence of the fluctuation results and the holographic hypothesis (in contrast to some recent statements in that direction) we show that by combining these two topics one can draw quite strong and interesting conclusions about the details of the fluctuation structure and the microscopic dynamics on the Planck scale. We further argue that these findings point to a possibly new and generalized form of quantum statistical mechanics of strongly (anti)correlated systems of degrees of freedom in this fundamental regime.

Quality management decisions require precise and reliable measuring results. In manufacturing and assembling processes, production metrology plays a significant role in generating such results. For this reason, coordinate measuring machines (CMMs) are used more and more often due to their universality and flexibility. The quality of results generated by CMMs is highly dependent on the skills of the CMM operators. In order to minimize technicians' influence, they need to be provided with the necessary knowledge to carry out such tasks. Efforts to introduce training at a national level led to the European project EUKOM, which developed a usercentred training course using new learning methods to meet the demands of CMM operators [1]. This project led to the foundation of the registered association CMTrain. Today, this association offers manufacturer-independent courses in coordinate metrology and it is continually improving learning methods and learning contents.

Cosmic rays, mostly composed of high energy muons, continuously hit the Earth's surface (at sea level the rate is about 10 000 m -2 min -1 ). Various technologies are adopted for their detection and are widespread in the field of particle and nuclear physics. In this paper, cosmic ray muon detection techniques are assessed for measurement applications in engineering, where these methods could be suitable for several applications, with specific reference to situations where environmental conditions are weakly controlled and/or where the parts to be measured are hardly accessible. Since cosmic ray showering phenomena show statistical nature, the Monte Carlo technique has been adopted to numerically simulate a particular application, where a set of muon detectors are employed for alignment measurements on an industrial press. An analysis has been performed to estimate the expected measurement uncertainty and system resolution, which result to be strongly dependent on the dimensions and geometry of the set-up, on the presence of materials interposed between detectors and, ultimately, on the elapsed time available for the data taking.

The paper addresses one of the new and most important issues arising when Low Power Voltage Transformers (LPVTs) are used in power network substations for evaluating, among others, the residual voltage measurement. Conversely to open-triangle inductive instrument transformers, the use of phase voltage transformers for measuring the residual voltage gets challenging due to the very high accuracy required for the three LPVTs. In the paper, a general expression to estimate the residual voltage measurement uncertainty, starting from the LPVTs accuracy, is presented. The effectiveness of the proposed approach is then confirmed with both Monte Carlo simulations and actual measurements on a general three-phase system.

The measurement of uncertainties in scientific experiments improves greatly quality and reliability of the results. However, in many cases, experimental results are only expressed by its average value and standard deviation. The longitudinal velocity and attenuation coefficient are acoustic parameters commonly used to characterize biological tissues and materials. In this work it is studied the uncertainty in experiments designed to evaluate these parameters on two different materials (silicone rubber and PVCP). The uncertainties were studied following the Guide to the Expression of Uncertainty in Measurement and calculated by a program in Labview8.6. One setup was developed to measure the acoustic parameters by a transmission/reception technique. Five signals of each medium (water and materials) were collected. The attenuation coefficient was calculated using the relation between the amplitude spectrum peak of the water signal and its respective point on the spectrum of the material signal. The longitudinal velocity was calculated using the time delay between signal peaks (from water and from the material). The individual uncertainties of each part of setup were estimated and these values permitted to identify which were the sources of uncertainty that most contributed to increase the value of associated uncertainty. It permitted to improve experiment's quality and reliability.

Spectroradiometry is a key metrological topic for accurate testing of photovoltaic (PV) devices, particularly relevant both for indoor testing on solar simulators and for outdoor testing. The relevance of accurate measurements of solar spectral irradiance has led the most renowned European solar PV test centres to take part to a series of International Spetroradiometer Intercomparisons that has taken place every year so far since 2011 in various localities in the Mediterranean Basin. This paper revisits the performance of participant laboratories and highlights the importance of inter-laboratory comparisons, showing the possible improvements in measurement reproducibility.

The acquisition and appropriate processing of relevant information about the considered system remains a major challenge in assessment of existing structures. Both the values and the validity of computed results such as failure probabilities essentially depend on the quantity and quality of the incorporated knowledge. One source of information are onsite measurements of structural or material characteristics to be modeled as basic variables in reliability assessment. The explicit use of (quantitative) measurement results in assessment requires the quantification of the quality of the measured information, i.e., the uncertainty associated with the information acquisition and processing. This uncertainty can be referred to as measurement uncertainty. Another crucial aspect is to ensure the comparability of the measurement results.This contribution attempts to outline the necessity and the advantages of measurement uncertainty calculations in modeling of measurement data-based random v...

This paper presents a set of modular test parts specially designed for the evaluation of the extraction operation using CT measuring systems. The motivation in developing the test parts was to individually quantify different types of CT-induced measurement errors and their influence on measurement results. The characteristics of the test parts and the evaluation procedure used to access different types of measurement errors are described. An experimental study using the test parts is included. Discussions on the use of the test parts for evaluating the metrological performance of CT systems are carried out.

The application of computed tomography (CT) is growing rapidly in the field of dimensional metrology. In the current state of the art, however, CT-systems cannot provide the same accuracy as tactile coordinate measuring systems, and one of the main reasons is the high level of noise generated in CT measurements. This paper presents an experimental approach to investigate the influence of the extraction operation on geometrical evaluations performed with CT-systems. The methodology consists in performing systematic experiments using different setup parameters on calibrated workpieces; and comparing characteristics of the extracted integral features in both the space and the frequency domains. The approach was used to analyse a set of CT measurement data extracted with different setup parameters and evaluated with different verification operators. The results demonstrate that distortions generated during the extraction operation with CT systems may have great impact on the results of geometrical evaluations. In this context, the analysis of the integral extracted features obtained with systematic experiments showed to be a useful tool to evaluate the quality of the extraction operation, and thus, to define the setup parameters in order to improve the accuracy of geometrical evaluations.

Measurement uncertainty is a quality indicator that is used to show the distribution level of a test result in a laboratory. The aim of this study is to calculate the measurement uncertainty of ten biochemical parameters investigated in our laboratory and compare the obtained values with the permissible total error values (% TEa), which various authorities determine for these tests. The measurement uncertainty of glucose, ALT, AST, urea, creatinine, sodium, potassium, albumin, total protein and total cholesterol were investigated in the biochemical auto analyzer (Siemens Advia 2400). Fifty randomly selected 2 level (low and high) internal quality assessment results and external quality assessment of six-month data, the first six months of 2016, were calculated for each test. Nordtest guide was used for the measurement uncertainty calculation. The measurement uncertainties were calculated as 3.9%, 6.72%, 3.4%, 8.06%, 9.06%, 6.08%, 5.02%, 4.98%, 4.96% and 7.22% for glucose, ALT, AST, urea, creatinine, albumin, total protein and total cholesterol, respectively. The calculated measurement uncertainties were found to be lower than the CLIA'88 and RiLi-BEAK % TEa values, except for sodium. Calculated % TEa values for creatinine, sodium, total protein and albumin were found to be higher than Fraser % TEa values. A test result or a measurement is not sufficiently effective when reliability is not assessed. Laboratories should calculate the measurement uncertainty for each parameter. They should give the results that do not exceed the targeted % TEa values. Clinicians should be informed about the measurement uncertainties so that they consider it while evaluating patient results.

Measurement uncertainty is a quality indicator that is used to show the distribution level of a test result in a laboratory. The aim of this study is to calculate the measurement uncertainty of ten biochemical parameters investigated in our laboratory and compare the obtained values with the permissible total error values (% TEa), which various authorities determine for these tests. The measurement uncertainty of glucose, ALT, AST, urea, creatinine, sodium, potassium, albumin, total protein and total cholesterol were investigated in the biochemical auto analyzer (Siemens Advia 2400). Fifty randomly selected 2 level (low and high) internal quality assessment results and external quality assessment of six-month data, the first six months of 2016, were calculated for each test. Nordtest guide was used for the measurement uncertainty calculation. The measurement uncertainties were calculated as 3.9%, 6.72%, 3.4%, 8.06%, 9.06%, 6.08%, 5.02%, 4.98%, 4.96% and 7.22% for glucose, ALT, AST, urea, creatinine, albumin, total protein and total cholesterol, respectively. The calculated measurement uncertainties were found to be lower than the CLIA'88 and RiLi-BEAK % TEa values, except for sodium. Calculated % TEa values for creatinine, sodium, total protein and albumin were found to be higher than Fraser % TEa values. A test result or a measurement is not sufficiently effective when reliability is not assessed. Laboratories should calculate the measurement uncertainty for each parameter. They should give the results that do not exceed the targeted % TEa values. Clinicians should be informed about the measurement uncertainties so that they consider it while evaluating patient results.

In this paper, we propose an approach to construct highly accurate 3D object models from range data. The main advantage of sensor based model acquisition compared to manual CAD model construction is the short time needed per object. The usual drawbacks of sensor based model reconstruction are sensor noise and errors in the sensor positions which typically lead to less accurate models. Our method drastically reduces this problem by applying a physical model of the underlying range sensor and utilizing a graph-based optimization technique. We present our approach and evaluate it on data recorded in different real world environments with an RGBD camera and a laser range scanner. The experimental results demonstrate that our method provides more accurate maps than standard SLAM methods and that it additionally compares favorable over the moving least squares method.

The history of standardization relating to the activities of medical laboratories traces the development of quality system standards in the world, and their evolution. Content: In this study, we have included the key benchmarks that represent the stages of the quality system's evolution in recent decades. Accreditation of medical laboratories has become compulsory in most countries, regarding national or international standards. International acknowledgment of the effectiveness of the results delivered to the many stakeholders, particularly patients and prescribers, is conferred through the use of standards. Summary: The ISO 15189 standard represents the latest and most specific international standards for medical laboratories of all types. Outlook: More research is necessary to study if laboratory practices reflect the evolution of standards within the medical laboratory field.

Time-reversed evolution has substantial implications in physics, including prominent applications in refocusing of classical waves [1][2][3] or spins [4] and fundamental researches such as quantum information scrambling [5][6][7][8]. In quantum metrology[9, 10], nonlinear interferometry based on time reversal protocols supports entanglement-enhanced measurements without requiring low-noise detection. Despite the broad interest in time reversal, it remains challenging to reverse the quantum dynamics of an interacting many-body system as is typically realized by an (effective) sign-flip of the system's Hamiltonian. Here, we present an approach that is broadly applicable to cyclic systems for implementing nonlinear interferometry without invoking time reversal. Inspired by the observation that the time-reversed dynamics drives a system back to its starting point, we propose to accomplish the same by slaving the system to travel along a 'closed-loop' instead of explicitly tracing back its antecedent path. Utilizing the quasi-periodic spin mixing dynamics in a threemode 87 Rb atom spinor condensate, we implement such a 'closed-loop' nonlinear interferometer and achieve a metrological gain of 3.87 +0.91 -0.95 decibels over the classical limit for a total of 26500 atoms. Our approach unlocks the high potential of nonlinear interferometry by allowing the dynamics to penetrate into deep nonlinear regime, which gives rise to highly entangled non-Gaussian state. The idea of bypassing time reversal may open up new opportunities in the experimental investigation of researches that are typically studied by using time reversal protocols.

Ocean radar backscatter in the presence of large waves is investigated using data acquired with the Jet Propulsion Laboratory NUSCAT radar at Ku band for horizontal and vertical polarizations and the University of Massachusetts C-SCAT radar at C band for vertical polarization during the Surface Wave Dynamics Experiment. Off-nadir backscatter data of ocean surfaces were obtained in the presence of large waves with significant wave height up to 5.6 m. In moderate-wind cases, effects of large waves are not detectable within the measurement uncertainty and no noticeable correlation between backscatter coefficients and wave height is found. Under high-wave lightwind conditions, backscatter is enhanced significantly at large incidence angles with a weaker effect at small incidence angles. Backscatter coefficients in the wind speed range under consideration are compared with SASS-II (Ku band), CMOD3-H1 (C band), and Plant's model results which confirm the experimental observations. Variations of the friction velocity, which can give rise to the observed backscatter behaviors in the presence of large waves, are presented.

In the following we propose a technique for determining the shielding effectiveness of an electrically small enclosure with an electrically small aperture. In particular, we use this technique to explore the shielding characteristics of rectangular boxes used to shield devices. Measurement and simulation results are presented in order to validate the technique and to show that, when a source is placed inside the box, different aperture shapes on the face of the enclosure will produce different internal and external field patterns, and have different shielding characteristics.

Single pressure refractive index gas thermometry (SPRIGT) is a novel primary thermometry, jointly developed by TIPC of CAS in China and LNE-Cnam in France. To realize a competitive uncertainty of 0.25 mK for thermodynamic temperature measurements, high-stability and low-uncertainty of microwave resonance frequency measurements better than 2 ppb should be achieved. This article describes how to realize high-stability and low-uncertainty of resonance frequency measurements in a copper microwave cavity by experimental optimization methods based on Allan analysis of variance. In this manner, 10 -12 level accuracy and stability of microwave resonance frequency measurements were realized with an integration time of 3 hours, which is nearly 20 times better than those without optimization in our previous work (Sci. Bull 2019; 64: 286-288). It has potential applications in gas metrology and other research fields, where high-stability and low-uncertainty microwave measurements are necessary. Besides, microwave measurements were carried out isobarically at pressures of (30, 60, 90, and 120) kPa over the temperature range of (5 to 26) K, with good microwave mode consistency for the determined thermodynamic temperatures. These will provide strong support for the success of the implementation of SPRIGT in China.

A series of in-band and out-of-band transmittance measurements of filters covering the wavelength range from 317 to 1019 nm and a linear variable filter for the 300 to 400 nm range have been made. The bandpass filters and the linear variable were fabricated using the ion-assisted-deposition or similar processes. The radiometric stability of the central wavelength, bandpass (FWHM), and peak transmittances were measured before and after exposures to combined high temperature and humidity, a thermal vacuum cycle, an ionizing particle radiation environment, flight on the Space Shuttle and at two temperature ranges. Representative radiative signal-to-noise ratios are given for solar irradiance observations with a silicon photodiode detector.

Laboratory results are important data that aid in diagnosis, monitoring, and prognosis. However, the variation of the results occurs once the same sample is retested due to several factors. Uncertainty of the measurement indicates how much these factors affect the result. The uncertainty of %CD4+T cell measurement within the Flow Cytometry Unit, Faculty of Associated Medical Sciences, Chiang Mai University were estimated by using the results of internal quality control and external quality assessment during 2012–2013 to comply with the requirements of ISO 15189: 2012. The procedures of this study included 1) Estimation of the uncertainty of measurement, 2) Reporting of the uncertainty of measurement, 3) Assessment of the uncertainty of measurement for clinical fitness purpose, and 4) Clinical use of the uncertainty information for clinical monitoring. The results of uncertainty measurements of the year 2012 and 2013 were 6.8% and 6.2% respectively at 95% confident level. In conclusi...

In this paper, the problem of frequency and phasor estimation in three-phase systems is considered. Three-phase electrical signals are composed of three components that can be jointly exploited to improve the estimation performance. To exploit this property, most of the existing estimation algorithms are based on a linear preprocessing called the Clarke Transform. In this study, we investigate a more general situation where the preprocessing is obtained from a semi-orthogonal transform. This situation encompasses several strategies such as the singlephase estimator, the optimal three-phase estimator and the Clarke-based estimator. For this general situation, we derive the Maximum Likelihood Estimator of the angular frequency and complex phasors. We also examine how the choice of a particular semi-orthogonal transform affects the estimation performance, and present a new technique that statistically outperforms the Clarke Transform. Regarding the estimation performance under noisy environment, we also introduce and derive a new criterion called the probability of IEEE C37.118 Standard compliance.

Network topology plays a critical role while designing and evaluating network protocols. Most existing topology generators are insufficient to reflect the real world network demands to a topology or to capture the Internet topology evolution such as the "flattening" Internet. They focused on the graph properties of a topology, thus, lacking of ability to model engineering features of the network. Some state-of-art topology generators that consider engineering factors fail to capture trends in both intra-AS and inter-AS connections, which are equally important for evaluating future network protocols. We have developed a topology generator GeoTopo, which is to our best knowledge the first scalable topology generator modeling engineering factors for both intra-AS and inter-AS topology generation. The engineering factors that GeoTopo considers include demographic and geographic features as well as business interests of ASes. We use GeoTopo to create and study three classes of topologies: the topology characterized mainly by graphproperties (Status Quo topology), the topology driven by peering at Internet Exchange Points (IXP topology) and the topology characterized by country backbones (CB topology). The SQ topology follows the degree-based model and serves as a baseline for capturing topology features. The IXP and CB topologies model two major directions of the Internet "flattening". The three classes of topologies enable us to analyze the impact of engineering factors on topology generation such as AS peering policies, IXP deployment and AS geo-settings. GeoTopo's ability to generate projected future Internet topologies make it a valuable tool for the design and evaluation of Future Internet Architectures that is currently under consideration in the research community. We use the evaluation of Global Name Resolution Service (GNRS), a key component shared by name-based network architectures, as an example application to demonstrate GeoTopo's capability to capture the mobility of network entities, the locality of the traffic, and the impact of the evolving network.

We investigate uncertainties in the Atmospheric Infrared Sounder (AIRS) radiances based on in-flight and preflight calibration algorithms and observations. The global coverage and spectra1 resolution (X/AX --1200) of AIRS enable it to produce a data set that can be used as a climate data record over the lifetime of the instrument. Therefore, we examine the effects of the uncertainties in the calibration and the detector stability on future climate studies. The uncertainties of the parameters that go into the AIRS radiometric calibration are propagated to estimate the accuracy of the radiances and any climate data record created from AIRS measurements. The calculated radiance uncertainties are consistent with observations. Algorithm enhancements may be able to reduce the radiance uncertainties by as much as 7%. We find that the orbital variation of the gain contributes a brightness temperature bias of < 0.01 K. Although this can be removed by algorithm enhancements, it is smaller than uncertainty of the gain for most channels.

This paper aims at characterizing and improving the metrological performances of Current (CT) and Voltage Instrument Transformers (VT) in harmonic measurements in power system. A theoretical analysis is carried out to demonstrate that, due to the iron core non linearity, CT and VT output signal is distorted even when the input signal is a pure sinusoidal. Starting from this analysis, a new method for CT and VT characterization and compensation is proposed. In a first step, they are characterized in sinusoidal conditions and the harmonic phasors of the distorted output are measured; in the second step, these phasors are used to compensate the harmonic phasors measured in normal operating conditions, which are typically distorted. The proposed characterization and compensation techniques are called SINDICOMP (SINusoidal characterization for DIstortion COMPensation). Several experimental tests, using high accuracy calibration setups, have been performed to verify the proposed methods. The experimental results showed that the SINDICOMP technique assures a significant improvement of CT and VT metrological performances in harmonic measurements.

This paper presents the development of a highaccuracy sampling wattmeter, which can be employed with both sinusoidal and distorted input signals. The proposed personal computer (PC)-based system is a simple, portable, and low-cost solution because it is based on two commercial data acquisition boards connected to a common PC. Owing to this solution, the voltage is sensed directly, avoiding expensive voltage dividers, while the current is sensed by means of a noninductive current shunt. Commercial software is also used for data processing and implementation of the virtual instrument. The setup of the PC-based wattmeter is described, with a detailed description of the correction strategy of systematic contributions to the measurement uncertainty of analog-to-digital converter conversion. An experimental evaluation of its metrological performances is made by means of several experimental tests, with both sinusoidal and distorted voltages and currents, which were carried out with an electric power standard and a high-performance multifunction calibrator.

The standard ISO/IEC 17025:2005 "General requirements for the competence of testing and calibration laboratories" introduces the necessity of evaluation of measurement uncertainties for making them reliable and comparable. In order to fulfill acoustic comfort conditions indoors, building acoustic have to establishes a set of criteria for the acoustic performance of the building. These criteria may be expressed in terms of permissible minimum values for normalized noise reduction NNR, noise reduction NR or apparent transmission loss ATL. This paper discusses the uncertainty sources and presents a methodology for the calculation of uncertainty of the airborne sound insulation between rooms carried out according to the of standards ASTME 336 and examples of uncertainty budget, evaluated for the measurement results of the sound insulation. The range of values obtained for the measurement results uncertainty is 0.68 to 1.77.

Measuring the 3 components of the velocity in a large area of a turbulent flow requires the stereoscopic DPIV system. On most flow facilities, positioning the camera in a symmetric way is not possible. The accuracy may change between different angle set-up. Asymmetric and symmetric set-up are compared using an angular stereoscopic DPIV system with Scheimpflug conditions. The data consist of nine set-up with different camera angles. The measured displacement is compared to the actual displacement of a paper pattern mounted on a 3D translation stage. The warping method followed by a geometrical reconstruction are used to compute 3D vector field. The main accuracy behaviours of the angle set-up are depicted using mainly the aperture angle aa (angle in between the two camera) and asymmetry angle (difference of camera angles). Simple rules can be laid out such as: -the more asymmetric is the set-up and the larger is the aperture angle, the more accurate the system is -high aperture angle should be preferred to the location of the stereoscopic system -symmetric system with a aa around 60° is a good compromise, regarding to accuracy and space consuming

This paper describes the use of a synthetic image generator (SIG) for the assessment of the precision of a stereoscopic PIV system. The geometry implemented with the SIG closely matches that of an existing stereo-PIV measurement in laminar pipe flow. The calibration procedure is simulated, which demonstrates the necessity of a careful alignment between the calibration target and the light-sheet plane. This demonstrates the possibilities for determining the tolerances for alignment and optical configuration prior to the actual measurement, which can save substantial costs during measurement campaigns in wind tunnel facilities.

Many industries, such as manufacturing, aviation, and power generation, employ sensitive measurement devices to be calibrated by certified experts. The diversity and sophistication of measurement devices and their calibration needs require networked and automated solutions. Internet of Measurement Things (IoMT) is an architectural framework that is based on the Industrial Internet of Things for the calibration industry. This architecture involves a layered model with a cloud-centric middle layer. In this article, the realization of this conceptual architecture is described. The applicability of the IoMT architecture in the calibration industry is shown through an editor application for Scope of Accreditation. The cloud side of the implementation is deployed to Microsoft Azure. The editor itself is created as a cloud service, and IoT Hub is used to collect data from calibration laboratories. By adapting the IoMT architecture to a commonly used cloud platform, considerable progress is achieved to encompass Metrology data and serve the majority of the stakeholders.

Several monitoring, protection, and control applications designed for modern power grids are based on detailed grid models and thus require an accurate knowledge of line parameters. A synchronized monitoring infrastructure based on Phasor Measurement Units (PMUs) may be of great support to the task of line parameters estimation, but the accuracy of the estimated parameters may be largely affected by the uncertainty of all the elements of the PMU-based measurement chain. Thus, an accurate parameters estimation must appropriately consider the metrological behavior of all these elements, and in particular that of instrument transformers. To address this challenge, the paper proposes an enhanced multi-branch method for accurate estimation of the line parameters and of the systematic measurement errors introduced by the instrument transformers when measurements for multiple operating conditions are considered. Indeed, multiple operating conditions are dealt with properly, thanks to an in-depth analysis of the problem modeling within the framework of Tikhonov regularization. The validity of the proposed approach is confirmed by the results obtained on the IEEE 14 bus test system.

Upon exiting the refinery, fuel products are distributed to vessels, from vessels to the terminals conducting the activities of fuel storage and distribution operations, and from terminals to stations via road tanker. Problems of loss in the product quantities occur after the movements of displacement of the product in terminal tanks and simultaneous the movements during filling operations. In this paper all operation processes of one of the fuel oil terminal in Turkey. The fuel products were received upon the unloading of the vessel and storage and distribution activities were carried out in this terminal. The elements causing loss during the terminal operation processes were examined with the failure modes and effects analysis (FMEA) technique. According to this analysis, the fields for which measures would be taken with precedence and a solution approach were presented for the company. While this approach is providing the causes of occurrence of failures as well as the control of loss for the company, the risk of fire and spillage likely to occur can be prevented as well.

Active learning (AL) has found wide applications in medical image segmentation, aiming to alleviate the annotation workload and enhance performance. Conventional uncertaintybased AL methods, such as entropy and Bayesian, often rely on an aggregate of all pixel-level metrics. However, in imbalanced settings, these methods tend to neglect the significance of target regions, eg., lesions, and tumors. Moreover, uncertainty-based selection introduces redundancy. These factors lead to unsatisfactory performance, and in many cases, even underperform random sampling. To solve this problem, we introduce a novel approach called the Selective Uncertainty-based AL, avoiding the conventional practice of summing up the metrics of all pixels. Through a filtering process, our strategy prioritizes pixels within target areas and those near decision boundaries. This resolves the aforementioned disregard for target areas and redundancy. Our method showed substantial improvements across five different uncertainty-based methods and two distinct datasets, utilizing fewer labeled data to reach the supervised baseline and consistently achieving the highest overall performance. Our code is available at Uncertainty AL.

This document describes a calibration protocol with the intention to introduce a guide to standardize the metrological vocabulary among manufacturers of image-guided surgery systems. Two stages were developed to measure the errors and estimate the uncertainty of a neuronavigator in different situations, on the first one it was determined a mechanical error on a virtual model of an acrylic phantom, on the second it was determined a coordinate error on the computerized axial tomography scan of the same phantom. Ten standard coordinates of the phantom were compared with the coordinates generated by the NeuroCPS. After measurement model was established, there were identified the sources of uncertainty and the data was processed according the guide to the expression of uncertainty in measurement.

Indoor noise can greatly affect the health and comfort of users, so the significance of the right assessment of the compliance with the requirements is obvious. But noise level testing is carried out using different methods, which may not ensure consistency in assessments The paper presents the influence of test methods on measurement results determined based on an analysis of inter-laboratory comparative studies. The analyses presented in the paper apply to an equivalent sound pressure level determined for a permanent source of sound -an air-conditioning device. The test methods were characterised according to their precision. In order to compare them, their compatibility was analysed based on the methodology described in the literature, alongside a single-factor analysis of variance. It was determined that there were no grounds for rejecting the hypothesis about lack of statistical differences between the results obtained via different methods. Each of the methods is characterised by different precision, so consequently the same result obtained with each method carries a different risk in regards to noise assessment. The reason for taking up this kind of research was the decision of the Polish Technical Committee in 2018 about introducing new acoustic requirements in Poland concerning the admissible indoor sound pressure levels. It was decided to implement new international methods of testing indoor sound pressure levels emanating from the service equipment in the building. It was necessary to show the differences between the current method and its new counterparts.