In this work we consider one-sided EWMA and CUSUM charts with one Shewhart-type control limit, and study their performance in the detection of shifts, of different magnitude, in the parameters of a two-parameter exponential distribution. Using Monte Carlo simulation, we calculate the run length distribution of the considered charts and evaluate their performance, focusing on the average run...
A single Shewhart chart based on a Max-type statistic has been suggested for monitoring a process using one control charts, based on a single plotting statistic, and detecting changes in its parameters. To improve its power, it is suggested to apply one or more supplementary rules based on run statistics, known as runs rules. Supplementary runs rules have been used since the 1950s to improve...
Monitoring time between events, operational delays or responding to a customer call is essential for maintaining and thriving to enhance service quality. Several aspects of the processes, including location such as median time, variability and shape, are pivotal. This paper introduces a Phase-II distribution-free cumulative sum (CUSUM) procedure based on a combination of three orthogonal rank...
The exponentially weighted moving average (EWMA) control chart was proposed already in 1959 and it became one of the most popular devices in statistical process monitoring (SPM) in the last decade of the previous century. Besides its most popular version for monitoring the mean of a normal distribution, many other statistical parameters were deployed as target for setting up an EWMA chart....
Modern industrial systems generate high-dimensional data streams often used for statistical process monitoring (SPM), i.e., distinguishing between multiple in-control and out-of-control (OC) states. While supervised SPM methods benefit from labeled data in assessing the process state, label acquisition is often expensive and infeasible at large scale. This work proposes a novel stream-based...
Nowadays, big data is generated real-time in the majority of industrial production processes. Happenstance data is characterized by high volume, variety, velocity and veracity (4v of big data).
In this study production data from industrial purification process is analyzed to assess process performance and its relations with product quality. For this purpose, a comprehensive data...
Statistical Process Control (SPC) and its numerous extensions/generalisations focus primarily on process monitoring. This permits identification of out-of-control signals, which might be isolated out-of-control observations or a more persistent process aberration, but says nothing about remedying or controlling them. While isolated out-of-control signals require isolated interventions, a more...
Many chemometrics methods like Principal Component Analysis (PCA) function under the assumption of time independent observations, which may not be valid in most industrial applications. This is particularly true when PCA is employed for multivariate statistical process control. To handle time dependent data, Dynamic PCA (DPCA) has been proposed, which incorporates expanding the feature matrix...
Dynamic pricing has emerged as a powerful mechanism for adapting product and service prices in real time, based on fluctuating market conditions, customer behavior, and operational constraints. In this work, we explore a novel approach to dynamic pricing that leverages techniques from statistical process monitoring and probability modelling toolboxs. Through a series of simulations as well as...
Turboprop engines undergo regular inspections, yet continuous analysis of in-flight sensor data provides an opportunity for earlier detection of wear and degradation—well before scheduled maintenance. The choice of statistical method plays a crucial role in ensuring diagnostic accuracy and interpretability. In this study, we compare the performance of traditional parametric...
The power curve of a wind turbine describes the generated power as a function of wind speed, and typically exhibits an increasing, S-shaped profile. We suggest to utilize this functional relation to monitor the wind energy systems for faults, sub-optimal controls, or unreported curtailment. The problem is formulated as a regression changepoint model with isotonic shape constraints on the model...
Electric batteries are often connected in parallel to ensure a wider power supply range to external electrical loads. Their condition is routinely monitored through the current measured when the batteries supply power. When the condition is adequate, the current is balanced throughout the system, with each battery contributing equally to the electrical load.
To ensure that monitoring focuses...
The Shiryaev’s change point methodology is a powerful Bayesian tool in detecting persistent parameter shifts. It has certain optimality properties when we have pre/post-change known parameter setups. In this work we will introduce a self-starting version of the Shiryaev’s framework that could be employed in performing online change point detection in short production runs. Our proposal will...
Statistical process monitoring (SPM) is used widely to detect changes or faults in industrial processes as quickly as possible. Most of the approaches applied in industry are based on assuming that the data follows some parametric distribution (e.g., normality). However, in industry this assumption is not always feasible and limits the application and usefulness of SPM for fault detection. In...
Recent advances in the Internet of Things (IoT) and sensor technologies have provided powerful tools for the continuous, real-time monitoring of highly complex systems characterized by a wide range of features. This is particularly relevant for HVAC systems in buildings, where the objective is to maintain appropriate levels of hygrothermal comfort while minimizing energy consumption. As such,...