This paper examines how the dynamic information present in a multivariate set of data can be used to improve the performance of a monitoring scheme of the multivariate mean. Optimum performance of such a scheme requir...
详细信息
This paper examines how the dynamic information present in a multivariate set of data can be used to improve the performance of a monitoring scheme of the multivariate mean. Optimum performance of such a scheme requires the use of the covariance/correlation matrix of the time-lagged variables. In the general case, this would require variables to be lagged with respect to one another. A Statistical processcontrol scheme is described where the Mahalanobis distance is monitored based on optimally lagged variables. The benefits of the method are demonstrated using Monte Carlo simulations.
Traditionally Principal Components Analysis (PCA) has been viewed as a single group method and in particular, in multivariate statistical performance monitoring (MSPM), it has been used as a monitoring and diagnostic ...
详细信息
Traditionally Principal Components Analysis (PCA) has been viewed as a single group method and in particular, in multivariate statistical performance monitoring (MSPM), it has been used as a monitoring and diagnostic tool for single product production. An extension to PCA is presented which enables a number of similar products or product grades to be monitored through a single multi-group model. The method is applied to a semi-discrete industrial batch manufacturing process. The industrial application illustrates that the detection and diagnostic capabilities of the generic model are comparable to those of a single group model.
This paper presents a model-based procedure for the detection and isolation of actuator faults in a chemical process. The diagnosis system is based on the estimation of process outputs. A dynamic Multi-input, multiple...
详细信息
This paper presents a model-based procedure for the detection and isolation of actuator faults in a chemical process. The diagnosis system is based on the estimation of process outputs. A dynamic Multi-input, multiple output (MIMO) process of the process under investigation is obtained by identification procedures, exploiting both Auto Regressive exogenous and Takagi-Sugeno (T-S) fuzzy input-output systems. Fuzzy systems are exploited to cope with different process working conditions. Residual analysis and geometrical tests are then used for fault detection and isolation, respectively. The proposed designs were evaluated using a benchmark simulation of a Continuous Stirred Tank Reactor.
The cost of implementing real-time monitoring and control of industrial processes is a significant barrier for many companies. Acoustic techniques provide complementary information to optical spectroscopic sensors and...
详细信息
The cost of implementing real-time monitoring and control of industrial processes is a significant barrier for many companies. Acoustic techniques provide complementary information to optical spectroscopic sensors and have a number of advantages: they are relatively inexpensive, can be applied non-invasively, are non-destructive, multi-point measurements are possible, opaque samples can be analysed in containers that are made from opaque materials (e.g. steel or concrete) and the analysis can be conducted in real-time. In this paper a new theoretical model is proposed which describes the transport of particles in a stirred reactor, their collision with the reactor walls, the subsequent vibrations which are then transmitted through the vessel walls, and their detection by an ultrasonic transducer. The particle-wall impact is modelled using Hertz-Zener impact theory. Experimental data is then used in conjunction with this (forward) model to form an inverse problem for the particle size distribution using a least squares cost function. Application of an integral smoothing operator to the power spectra greatly enhances the accuracy and robustness of the approach. One advantage of this new approach is that since it operates in the frequency domain, it can cope with the industrially relevant case of many particle-wall collisions. The technique will be illustrated using data from a set of controlled experiments. In the first instance a set of simplified experiments involving single particles being dropped in air onto a substrate are utilised. The second set of experiments involves particles in a carrier fluid being stirred in a reactor vessel. In each case the approach is able to successfully recover the associated particle size
The importance of the FDA PAT guidelines in pharmaceutical process design space can be influenced by the introduction of robust process malfunction and senor fault detection and diagnosis tools. The paper compares a m...
详细信息
The importance of the FDA PAT guidelines in pharmaceutical process design space can be influenced by the introduction of robust process malfunction and senor fault detection and diagnosis tools. The paper compares a multi-scale multi-block modelling approach with conventional multiway PCA approaches for batch process monitoring. A benchmark penicillin fermentation simulation is used to evaluate the two methodologies. Contributions plots with confidence bounds enhance the fault diagnosis potential of the approaches studied. The methodology is in the process of being evaluated in fermentation and batch cooling crystallisation.
Fault detection and diagnosis are important technologies for the safe and efficient operation of a chemical plant. This paper describes a sensor fault identification approach using variable reconstruction for dynamic ...
详细信息
Fault detection and diagnosis are important technologies for the safe and efficient operation of a chemical plant. This paper describes a sensor fault identification approach using variable reconstruction for dynamic systems. The proposed methodology extends sensor fault reconstruction for Canonical Variate Analysis based process performance monitoring which admits process dynamic behaviour in a natural way, and evaluates its capabilities compared to a dynamic PCA approach using a mathematical benchmark problem and a simulation of a closed loop controlled CSTR previously used for studying both simple and complex faults.
Increasing attention is being paid to reducing the time taken from discovery to defining a final fermentation production process. Multivariate statistical data analysis and chemometric techniques can play an important...
详细信息
Increasing attention is being paid to reducing the time taken from discovery to defining a final fermentation production process. Multivariate statistical data analysis and chemometric techniques can play an important role in contributing to the achievement of this aim by providing biologists and fermentation scientists with sophisticated data visualisation and data exploration tools. This paper presents a study of the application of a range of feature extraction techniques to data from shake flask experiments. investigatingrecombinant protein expression. carried out during the discovery phase of drug development.
Analytic expressions are found for the amplitude of the first and second harmonics of the Ultrasound Contrast Agent’s (UCA’s) dynamics when excited by a chirp. The dependency of the second harmonic amplitude on the ...
详细信息
Analytic expressions are found for the amplitude of the first and second harmonics of the Ultrasound Contrast Agent’s (UCA’s) dynamics when excited by a chirp. The dependency of the second harmonic amplitude on the system parameters, the UCA shell parameters, and the insonifying signal parameters is then investigated. It is shown that optimal parameter values exist which give rise to a clear increase in the second harmonic component of the UCA’s motion.
In a typical forensic investigation, fabric analysis plays a vital role in solving different crimes. Several types of textile fibre materials (cotton, polyester, denim, polypropylene, polycotton, and viscose) were ana...
详细信息
暂无评论