Academic literature on the topic 'Measurements uncertainty'

Measurement uncertainty is an indication of the quality of a given measurement and ultimately translates into the confidence with which a decision can be made. In the context of PV, measurement uncertainties propagate into energy yield uncertainty, which in turn culminates into financial risk associated with an investment. This risk increases the cost of a PV installation. The aim of this thesis is to contribute towards the reduction of PV related measurement uncertainties. This is done in two ways. One is via developing and utilising more comprehensive methodologies for uncertainty propagation of complex measurands. The other is via more detailed estimates of the uncertainty contributors. In particular, the areas addressed in this thesis are the uncertainty estimation of the temperature coefficient measurements of modules; the uncertainty estimation of energy rating and module performance ratio measurements; and the uncertainties due to spectral effects on measurements performed with a flash solar simulator. The reported deviation in measurements of the temperature coefficients of P_MAX of modules is in the order of ±10% to ±15%. This is larger than the difference in the temperature coefficients of modules of the same type. The first step to improving the deviation between measurements is to estimate the uncertainty in a robust way. It was identified that there was no accepted approach of doing this. These measurements are strongly correlated, which complicates the uncertainty estimates. For the sake of simplicity, previously correlations have been avoided and conservative estimates used instead. In this work, uncertainties in both temperature and power and their correlations are estimated and propagated into the overall temperature coefficient uncertainty. Furthermore, temperature coefficients were calculated via weighing the measurements with their associated uncertainties. This was done for five different measurement setups that represent the majority of setups used worldwide. The approach was validated with measurement intercomparison of two modules measured on all systems. The approach reduced the overall uncertainty by half compared to the previous conservative estimates. It was demonstrated that uncertainties as low as 3% are achievable. The improved uncertainty estimates enabled the identification of a systematic effect due to a class B spectrum. This work culminated in the lowest reported measurement deviation of ±3.2% for module P_MAXtemperature coefficient measurements that was within the stated measurement uncertainties. The clear benefit of accounting for correlations was extended to measurements at different irradiance conditions and into the calculation of module performance ratio and energy rating. This was done via defining all the correlations between measurements and then propagating them with Monte Carlo simulations. The simulations are done with samples of a multivariate normal distribution with a variance-covariance matrix that corresponds to the estimated measurement correlations. It is demonstrated that both the energy rating and module performance ratio uncertainties strongly depend on the correlation estimates and that they cannot be conservatively overestimated. The module performance ratio uncertainty can be significantly lower than the measurement uncertainty at STC. This is because of the additional knowledge encoded into the selection of the underlying model used for calculating the energy rating. Therefore, the significance of the choice of model in the upcoming standard has been highlighted. It was confirmed that both bilinear interpolation and the proposed climatic datasets could be used for energy rating, but there are some areas that may need further investigation. An alternative way of improving uncertainty estimates and in turn reducing the associated uncertainty is via a more detailed characterisation of the uncertainty sources. A key uncertainty source is due to spectral effects in flash solar simulators. To better quantify this source, a complementary device was built to monitor the spectrum. The device is based on a matrix of photodiodes with commercially available interference filters situated on top and custom designed data acquisition electronics. This device is used in conjunction with the spectroradiometer to estimate the effects of flash-variation on the spectrum, the spectral temporal stability of the flash and spectral uniformity of the simulator and the attenuation masks used for altering the irradiance levels. It was demonstrated that the spectrum changes significantly during the flash and between flashes. While this effect is partially corrected for via the monitoring cell, it introduces additional uncertainty for non c-Si modules. This uncertainty is minimised by changes in the operational procedures. The spectral non-uniformity of the attenuation masks was shown to be significant, i.e. as large as 4%, in the NIR, prompting further investigation of the additional uncertainty for non c-Si modules. In this work, the methodology of estimating and propagating correlations in PV related measurements and the benefits of doing so are demonstrated. It is also highlighted that the uncertainty due to spectral effects goes beyond the uncertainty of spectroradiometer measurements. Finally, it is shown how they can be estimated with a complementary spectral monitor.

Uncertainty relations express the fundamental incompatibility of certain observables in quantum mechanics. Far from just being puzzling constraints on our ability to know the state of a quantum system, uncertainty relations are at the heart of why some classically impossible cryptographic primitives become possible when quantum communication is allowed. This thesis is concerned with strong notions of uncertainty relations and their applications in quantum information theory.One operational manifestation of such uncertainty relations is a purely quantum effect referred to as information locking. A locking scheme can be viewed as a cryptographic protocol in which a uniformly random n-bit message is encoded in a quantum system using a classical key of size much smaller than n. Without the key, no measurement of this quantum state can extract more than a negligible amount of information about the message, in which case the message is said to be "locked". Furthermore, knowing the key, it is possible to recover, that is "unlock", the message. We give new efficient constructions of bases satisfying strong uncertainty relations leading to the first explicit construction of an informationlocking scheme. We also give several other applications of our uncertainty relations both to cryptographic and communication tasks.In addition, we define objects called QC-extractors, that can be seen as strong uncertainty relations that hold against quantum adversaries. We provide several constructions of QC-extractors, and use them to prove the security of cryptographic protocols for two-party computations based on the sole assumption that the parties' storage device is limited in transmitting quantum information. In doing so, we resolve a central question in the so-called noisy-storage model by relating security to the quantum capacity of storage devices.<br>Les relations d'incertitude expriment l'incompatibilité de certaines observables en mécanique quantique. Les relations d'incertitude sont utiles pour comprendre pourquoi certaines primitives cryptographiques impossibles dans le monde classique deviennent possibles avec de la communication quantique. Cette thèseétudie des notions fortes de relations d'incertitude et leurs applications à la théorie de l'information quantique.Une manifestation opérationnelle de telles relations d'incertitude est un effet purement quantique appelé verrouillage d'information. Un système de verrouillage peut être considéré comme un protocole cryptographique dans lequel un message aléatoire composé de n bits est encodé dans un système quantique en utilisant une clé classique de taille beaucoup plus petite que n. Sans la clé, aucune mesure sur cet état quantique ne peut extraire plus qu'une quantité négligeable d'information sur le message, auquel cas le message est "verrouillé". Par ailleurs, connaissant la clé, il est possible de récupérer ou "déverrouiller" le message. Nous proposons de nouvelles constructions efficaces de bases vérifiant de fortes relations d'incertitude conduisant à la première construction explicite d'un système de verrouillage. Nous exposons également plusieurs autres applications de nos relations d'incertitude à des tâches cryptographiques et des tâches de communication.Nous définissons également des objets appelés QC-extracteurs, qui peuventêtre considérés comme de fortes relations d'incertitude qui tiennent contre des adversaires quantiques. Nous fournissons plusieurs constructions deQC-extracteurs, que nous utilisons pour prouver la sécurité de protocoles cryptographiques pour le calcul sécurisé à deux joueurs en supposant uniquement que la mémoire des joueurs soit limitée en ce qui concerne la transmission d'information quantique. Ce faisant, nous résolvons une question centrale dans le modèle de mémoire bruitée en mettant en relation la sécurité et la capacité quantique de la mémoire.

In this thesis, the measurement uncertainty of Coordinate Measuring Machine (CMM) is analysed and software is designed to simulate this. Analysis begins with the inspection of the measurement process and structure of the CMMs. After that, error sources are defined with respect to their effects on the measurement and then an error model is constructed to compensate these effects. In other words, systematic part of geometric, kinematic and thermal errors are compensated with error modelling. Kinematic and geometric error model is specific for the structure of CMM under inspection. Also, a common orthogonal kinematic model is formed and with using the laser error data of the CMM and error maps of the machine volume is obtained. Afterwards, the models are compared with each other by taking the difference and ratio. The definition and compensation of the systematic errors leave the uncertainty of measurements for analysing. Measurement uncertainty consists of the uncompensated systematic errors and random errors. The other aim of the thesis is to quantify these uncertainties with using the different methods and to inspect the success of these methods. Uncertainty budgeting, comparison, statistical evaluation by designing an experiments and simulation methods are examined and applied to the CMM under inspection. In addition, Virtual CMM software is designed to simulate the task specific measurement uncertainty of circle, sphere and plane without using the repeated measurements. Finally, the performance of the software, highly depending on the mathematical modelling of machine volume, is tested by using actual measurements.

FINANCIADORA DE ESTUDOS E PROJETOS<br>MINISTÉRIO DA CIÊNCIA E TECNOLOGIA<br>Colorimetria - Propagação de erros e cálculo da incerteza da medição nos resultados espectrofotométricos trata da medição da cor de objetos, baseada nas medições de irradiância espectral (objetos luminosos) ou de refletância ou transmitância espectral (objetos opacos ou transparentes), seguidas por cálculos colorimétricos conforme o sistema CIE. As medições são normalmente feitas em intervalos de 5nm (ou 10 nm) na faixa espectral de 360 a 780nm, e os três valores triestímulos (X, Y e Z) são calculados usando-se 42-84 pontos medidos por equações padrões. A distribuição dos valores medidos R(lambda) é, provavelmente, normal, com uma correlação entre os valores obtidos variável em posições diferentes do espectro. As distribuições dos valores e as correlações entre X, Y e Z são desconhecidas e dependem da forma da curva espectral da cor e do funcionamento dos instrumentos de medição. No controle instrumental das cores são usadas fórmulas muito complexas, baseadas nas transformações não lineares dos valores X, Y e Z em L*, a*, b*, C* e h°. A determinação da incerteza dos resultados dados em coordenadas CIELAB ou expressos em fórmulas de diferenças (delta)E*, (delta) ECMC ou CIE (delta) E2000 é fundamental no controle instrumental das cores em qualquer indústria. À base de um número elevado de medições repetidas de várias amostras têxteis e padrões cerâmicos, são analisadas a distribuição e outras características estatísticas dos valores R(lambda) diretamente medidos, e - usando o método de propagação de erros - são calculadas as incertezas das medições em termos colorimétricos. A pesquisa de mestrado objeto do presente trabalho desenvolve- se sob a égide de um convênio de cooperação que o Programa de Pós-Graduação em Metrologia da PUC-Rio está celebrando com o SENAI/CETIQT, viabilizado a inclusão dessa pesquisa dentre os dez projetos-piloto que participaram do Convênio FINEP/MCT número 22.01.0692.00, Referência 1974/01, que aportou recursos do Fundo Setorial Verde Amarelo para direcionar o esforço de pesquisa em metrologia para a solução de um problema de interesse do setor têxtil que fez uso de conhecimentos avançados de metrologia da cor. Relacionado à demanda de medições espectrofotométricas com elevado controle metrológico, o desenvolvimento e a orientação acadêmico-científica da presente dissertação de mestrado deu-se nas instalações do SENAI/CETIQT, que possui comprovada competência técnica e científica na área e uma adequada infra-estrutura laboratorial em metrologia da cor de suporte ao trabalho.<br>Colorimetry - Propagation of Errors and Uncertainty Calculations in Spectrophotometric Measurements treats the measurement of the colour of objects, based on the measurement of spectral irradiance (self-luminous objects) or that of spectral reflectance or transmittance (opaque or transparent objects), followed by colorimetric calculations according to the CIE system. Measurements are generally made in 5nm (or 10 nm) intervals in the spectral range of 360 to 780nm, and the 3 tristimulus values (X, Y and Z) are calculated from the 42-84 measurement points by standard equations. The statistical distribution of the measured R (lambda) values is probably normal; the correlation between the values varies depending on their position in the spectrum. The distribution of and the correlation between the X, Y and Z values are not known and they depend on the form of the spectral curve of each colour and on the operation of the measuring instrument. Complex formulae are used in the instrumental control of colours based on non-linear transformations of the X, Y and Z values into L*a*b*C*h°. The determination of the uncertainty of the results given in CIELAB coordinates or expressed in one of the colour difference formulae (delta)E*, (delta)ECMC or CIE(delta) E2000 is fundamental in the instrumental control of colours in any industry. Based on a large number of repeated measurements of different textile samples and ceramic standards, the distribution and other statistical characteristics of the directly measured R(lambda) values are analysed and - using the propagation of errors method - the uncertainties are calculated in colorimetric terms. The present research, a M. Sc. Dissertation work, was developed under the auspices of a co-operation agreement celebrated between the Post-graduate Programme in Metrology of PUC-Rio and SENAI/CETIQT, allowing for the inclusion of this M.Sc. Dissertation among the ten pilot projects which benefited from the financial support received from the FINEP/MCT Agreement number 22.01.0692.00, Reference 1974/01 (Fundo Verde-Amarelo). The project aims at driving the research effort in metrology to the solution of industrial problems, in this case the solution of a problem identified within the textile sector which requires to its solution advanced knowledge of colour metrology. Related the spectrophotometer measurements under the highest level of metrological control, the development and academic-scientific supervision of this M. Sc. Dissertation was performed at the laboratory facility of SENAI/CETIQT, an institution with proven technical and scientific competence in the field having sophisticated and well equipped laboratories in colour metrology meeting the measurement requirements needed to support the development of this research.

Terahertz (THz) time domain spectroscopy is emerging as a powerful tool to characterise samples both chemically and physically. In this work different methods of estimating spectroscopic parameters of a sample, its thickness and the uncertainty of these estimates is presented. A number of case studies are also examined including paracetamol polymorphs and a method of creating a spectroscopic simulant of Semtex-H is presented. Approximation of the sample spectroscopic parameters, real refractive index and absorption coeficient were formed by building up a simple model of the samples interaction with THz radiation. Methods of correcting unwrapping error in the real refractive index were developed, including a method to correct in the presence of discontinuities in the refractive index itself. These approximations were then applied to extract parameters of both lactose and paracetamol samples. An algorithm to generate spectroscopic simulants was developed and applied to Semtex-H. These simulants consisted of simple mixtures of inert compounds, which were measured and found to have similar spectrum to the target sample. Methods of fitting resonant models to the sample response were developed to extract both the spectroscopic parameters and sample thickness. These were refined by calibrating for the Gaussian beam profile of the THz radiation, which was shown to increase the accuracy of the extracted thickness. The thickness and spectroscopic parameters of a lactose sample were measured with temperature, and it was found that the spectroscopic parameter change was underestimated when thickness was assumed constant. A resonant model for multilayered samples was then developed and used to characterise IPA in a flowcell measurement. This was then combined with a method of time segmentation of the sample response, to extract spectroscopic parameters and sample thickness simultaneously. This was then applied to a two layer sample, to extract the spectroscopic parameters of a silicon and a quartz layer from a single measurement. Finally, methods of propagating the uncertainty from the time domain to the spectroscopic parameters were developed. These were based on a multivariate normal statistical model of the measurements andwere compared to numerical bootstrap and Monte–Carlo estimates. These were used to develop confidence intervals for the extracted refractive index, absorption coefficient and thickness. These methods were applied to both a lactose and quartz sample.

In the context of “testing laboratory” one of the most important aspect to deal with is the measurement result. Whenever decisions are based on measurement results, it is important to have some indication of the quality of the results. In every area concerning with noise measurement many standards are available but without an expression of uncertainty, it is impossible to judge whether two results are in compliance or not. ISO/IEC 17025 is an international standard related with the competence of calibration and testing laboratories. It contains the requirements that testing and calibration laboratories have to meet if they wish to demonstrate that they operate to a quality system, are technically competent and are able to generate technically valid results. ISO/IEC 17025 deals specifically with the requirements for the competence of laboratories performing testing and calibration and for the reporting of the results, which may or may not contain opinions and interpretations of the results. The standard requires appropriate methods of analysis to be used for estimating uncertainty of measurement. In this point of view, for a testing laboratory performing sound power measurement according to specific ISO standards and European Directives, the measurement of uncertainties is the most important factor to deal with. Sound power level measurement, according to ISO 3744:1994 , performed with a limited number of microphones distributed over a surface enveloping a source is affected by a certain systematic error and a related standard deviation. Making a comparison of measurement carried out with different microphone arrays is difficult because results are affected by systematic errors and standard deviation that are peculiarities of the number of microphones disposed on the surface, their spatial position and the complexity of the sound field. A statistical approach could give an overview of the difference between sound power level evaluated with different microphone arrays and an evaluation of errors that afflict this kind of measurement. Despite the classical approach that tend to follow the ISO GUM this thesis present a different point of view of the problem related to the comparison of result obtained from different microphone arrays.

In quantum mechanics, measurements disturb the state of the system being measured. This disturbance is largest for complementary properties (e.g. position and momentum) and hence limits the precision with which such properties can be determined simultaneously. Often, this fact is conflated with Heisenberg's uncertainty principle, which refers to an uncertainty relation between complementary properties that is intrinsic to quantum states. In this thesis, the distinction between these two fundamental characteristics of quantum mechanics is made clear. At the intersection of the two are "joint measurements", which circumvent measurement disturbance to simultaneously determine complementary properties. They have applications in quantum metrology and enable a direct measurement of quantum states. The focus of this thesis is on the latter. The thesis is structured in the following way. The first chapter serves as an introduction to joint measurements. It surveys the seminal works in the field, doing so in a chronological manner to provide some historical context. The remainder of the thesis discusses two strategies to experimentally achieve joint measurements. The first strategy is to sequentially measure the complementary properties, making these measurements weak so that they do not disrupt each other. The second strategy is to first clone the system being measured, and then measure each complementary property on a separate clone. Both strategies are experimentally demonstrated on polarized photons, but can be readily extended to other systems.