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Quality Assurance and Validation
Published in Leo M. L. Nollet, Dimitra A. Lambropoulou, Chromatographic Analysis of the Environment, 2017
Roberta Galarini, Simone Moretti, Giorgio Saluti
Control charts involve plotting data in a time-ordered sequence. These data are, generally, the results obtained from successive analyses of a QC material. Thus, they allow the monitoring of the performance of the measurement system over time, detecting unusual variations in measurement results or the occurrence of a bias. The principle is that IQC data are graphically plotted so that that they can easily be compared and interpreted. Consequently, a control chart must be simple to use, understand, and act upon. Two types of control charts are commonly used in laboratories: accuracy or X-charts for QC samples, including reagent blanks, incurred reference materials, or spiked samples, and precision or range charts for replicate or duplicate analyses. These charts are essential tools for QC. Computer-generated and maintained lists or databases with values, limits, and trending may be used as an alternative to control charts.
Understanding Customer Demand: Forecasting
Published in Samuel H. Huang, Supply Chain Management FOR ENGINEERS, 2013
A time series is a time-ordered list of historical data. Time series models include constant, trend, and seasonal. For each model, there are several forecasting methods available, such as average, moving average, exponential smoothing, and regression. To select an appropriate model, one needs to study the historical data and understand the underlying process. We will discuss each model separately.
Pair and mediated RET between two chiral molecules
Published in Molecular Physics, 2022
Computation of the fourth-order matrix element for bridge-mediated energy transfer between two chiral molecules is facilitated by drawing time-ordered diagrams, of which there are twenty-four representing the permutation of the specific interaction vertices denoting the coupling of radiation with matter. Applying the standard calculational techniques of molecular QED theory yields the amplitude involving three-bodies [54] where the relative displacements and are defined as , and . Reflecting the fact that the mediator may absorb, emit or scatter the two virtual photons [19], M1 appears in the matrix element via the following ground state response tensor at the resonant wave vector,
A distribution-free Shewhart-type Mann–Whitney control chart for monitoring finite horizon productions
Published in International Journal of Production Research, 2021
Giovanni Celano, Subhabrata Chakraborti
Production monitoring starts by testing the reference sample x for stability. The recursive segmentation and permutation (RS/P) procedure from Capizzi and Masarotto (2013) is implemented by running the function within the R package , (R Core Team (2019)), developed by the same authors. With the RS/P procedure, the presence of one or multiple change-points is investigated for the reference sample x. If there are no changepoints, then the reference sample is considered in-control (IC). Testing for the significance about the presence of change-points is carried out by means of a permutation approach running on the set of time ordered observations within x. The RS/P procedure tests the reference sample x for both the location and scale stability: an overall false alarm rate is fixed. Interested readers can refer to Capizzi and Masarotto (2013) for further details about the test statistics to be used with the RS/P procedure and how they are tested. Figure 7 shows the plots obtained by running the R-function on x.
Socialising the decision-making process: transaction provenance decision support
Published in Journal of Decision Systems, 2020
A TPDS that incorporates a multi-sided provenance authentication platform, founded on PROV-O, enables us to establish and explore and authenticate the provenance of an entity involved in any particular transaction of interest transaction right back to its first transaction in which it was involved, marking that entity’s ‘creation’. This trace provides the Historical Provenance Chain for that entity: a time-ordered sequence of the complete set of transaction records involving the specific entity. The record for each transaction specifies the transaction type (barter, buy-sell, transfer of rights, gift, deposit or access) and providing data regarding the provenance attributes ‘when’, ‘where’, ‘what’, ‘how’, and ‘why’, building on and extending the World Wide Web Consortium’s Provenance Ontology, PROV-O.