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Cutting tool condition monitoring of the turning process using artificial intelligence
Get PDFThis thesis relates to the application of Artificial Intelligence to tool wear monitoring. The
main objective is to develop an intelligent condition monitoring system able to detect when a
cutting tool is worn out. To accomplish this objective it is proposed to use a combined Expert
System and Neural Network able to process data coming from external sensors and combine
this with information from the knowledge base and thereafter estimate the wear state of the
tool.
The novelty of this work is mainly associatedw ith the configurationo f the proposeds ystem.W ith
the combination of sensor-baseidn formation and inferencer ules, the result is an on-line system
that can learn from experience and can update the knowledge base pertaining to information
associated with different cutting conditions. Two neural networks resolve the problem of
interpreting the complex sensor inputs while the Expert System, keeping track of previous
successe, stimatesw hich of the two neuraln etworks is more reliable. Also, mis-classificationsa re
filtered out through the use of a rough but approximate estimator, the Taylor's tool life equation.
In this study an on-line tool wear monitoring system for turning processesh as been developed
which can reliably estimate the tool wear under common workshop conditions. The system's
modular structurem akesi t easyt o updatea s requiredb y different machinesa nd/or processesT. he
use of Taylor's tool life equation, although weak as a tool life estimator, proved to be crucial in
achieving higher performance levels. The application of the Self Organizing Map to tool wear
monitoring is, in itself, new and proved to be slightly more reliable then the Adaptive Resonance
Theory neural network
Preference modelling approaches based on cumulative functions using simulation with applications
Get PDFIn decision making problems under uncertainty, Mean Variance Model (MVM) consistent
with Expected Utility Theory (EUT) plays an important role in ranking preferences for
various alternative options. Despite its wide use, this model is appropriate only when
random variables representing the alternative options are normally distributed and the utility
function to be maximized is quadratic; both are undesirable properties to be satisfied with
actual applications.
In this research, a novel methodology has been adopted in developing generalized models
that can reduce the deficiency of the existing models to solve large-scale decision problems,
along with applications to real-world disputes. More specifically, for eliciting preferences for
pairs of alternative options, two approaches are developed: one is based on Mean Variance
Model (MVM), which is consistent with Expected Utility Theory (EUT), and the second is
based on Analytic Hierarchy Processes (AHP). The main innovation in the first approach is
in reformulating MVM to be based on cumulative functions using simulation. Two models
under this approach are introduced: the first deals with ranking preferences for pairs of lotteries/options with non-negative outcomes only while the second, which is for risk
modelling, is a risk-preference model that concerns normalized lotteries representing risk
factors each is obtained from a multiplication decomposition of a lottery into its mean
multiplied by a risk factor. Both approximation models, which are preference-based using
the determined values for expected utility, have the potential to accommodate various
distribution functions with different utility functions and capable of handling decision
problems especially those encountered in financial economics. The study then reformulates
the second approach, AHP; a new algorithm, using simulation, introduces an approximation
method that restricts the level of inherent uncertainty to a certain limit. The research further focuses on proposing an integrated preference-based AHP model
introducing a novel approximation stepwise algorithm that combines the two modified
approaches, namely MVM and AHP; it multiplies the determined value for expected utility,
which results from implementing the modified MVM, by the one obtained from processing
AHP to obtain an aggregated weight indicator. The new integrated weight scale represents
an accurate and flexible tool that can be employed efficiently to solve decision making
problems for possible scenarios that concern financial economics Finally, to illustrate how the integrated model can be used as a practical methodology to
solve real life selection problems, this research explores the first empirical case study on
Tender Selection Process (TSP) in Kurdistan Region (KR) of Iraq; it is considered as an
inductive and a comprehensive investigation on TSP, which has received minimum
consideration in the region, and regarded as a significant contribution to this research. The
implementation of the proposed model to this case study shows that, for the evaluation of
construction tenders, the integrated approach is an appropriate model, which can be easily
modified to assume specific conditions of the proposed project. Using simulation, generated
data allows creation of a feedback system that can be utilized for the evaluation of future
projects in addition to its capability to make data handling easier and the evaluation process
less complex and time consuming
Nurses in abortion care: identifying and managing stress
No full textThe psychological impact of abortion on the women undergoing the procedure is well researched, but little is known about the potential psychological impact on nurses working in abortion care. The proportion of medical abortions in the UK is rising compared to surgical abortions. A recent research
Energy-based models for environmental biotechnology
No full textEnvironmental biotechnology is evolving. Current process objectives include the production of chemicals and/or energy carriers (biofuels) in addition to the traditional objective of removing pollutants from waste. To maximise product yields and minimise biomass production, future processes will rely on anaerobic microbial communities. Anaerobic processes are characterised by small Gibbs energy changes in the reactions catalysed, and this provides clear thermodynamic process boundaries. Here, a Gibbs-energy-based methodology is proposed for mathematical modelling of energy-limited anaerobic ecosystems. This methodology provides a basis for the description of microbial activities as a function of environmental factors, which will allow enhanced catalysis of specific reactions of interest for process development
The occurrence of pharmaceuticals, personal care products, endocrine disruptors and illicit drugs in surface water in South Wales, UK
No full textAbstract The presence and fate of 56 pharmaceuticals, personal care products, endocrine disruptors and illicit drugs (PPCPs) were investigated in the South Wales region of the UK. Two contrasting rivers: River Taff and River Ely were chosen for this investigation and were monitored for a period of 10 months. The impact of the factors affecting the levels of concentration of PPCPs and illicit drugs in surface water such as surrounding area, proximity to wastewater effluent and weather conditions, mainly rainfall was also investigated. Most PPCPs were frequently found in river water at concentrations reaching single µg L-1 and their levels depended mainly on the extent of water dilution resulting from rainfall. Discharge of treated wastewater effluent into the river course was found to be the main cause of water contamination with PPCPs. The most frequently detected PPCPs represent the group of pharmaceuticals dispensed at the highest levels in the Welsh community. These were antibacterial drugs (trimethoprim, erythromycin-H2O and amoxicillin), anti-inflammatories/analgesics (paracetamol, tramadol, codeine, naproxen, ibuprofen and diclofenac) and antiepileptic drugs (carbamazepine and gabapentin). Only four PPCPs out of 56 (simvastatin, pravastatin, digoxin and digoxigenin) were not quantified over the course of the study. Several PPCPs were found to be both ubiquitous and persistent in the aqueous environment (e.g. erythromycin-H2O, codeine, carbamazepine, gabapentin and valsartan). The calculated average daily loads of PPCPs indicated that in total almost 6 kg of studied PPCPs are discharged daily into the studied rivers. The illicit drugs studied were found in rivers at low levels of ng L-1. Average daily loads of amphetamine, cocaine and its main metabolite benzoylecgonine were as follows: 8, 1.2 and 39 g day-1, respectively. Their frequent occurrence in surface water is primarily associated with their high illegal usage and is strongly associated with the discharge of insufficiently treated wastewater effluent
Authorship and the Director of Photography: a case study of Gregg Toland and Citizen Kane
No full textThe artistic contribution of Directors of Photography to the films that they shoot, in narrative mainstream cinema, have been historically ignored in favour of the director-centred auteur theory. In order to address this imbalance a new approach to attributing authorship in film needs to be implemented, which acknowledges co-authorship in collaborative film-making. By taking established auteur methodologies Philip Cowan, himself a practicing Director of Photography, analyses the work of Gregg Toland, who has long been recognised for his technical contribution to Citizen Kane (Welles, 1941), but only by analysing his previous work can one actually realise the depth of his influence on the visualisation of Kane
Terminology web services
No full textControlled terminologies such as classification schemes, name authorities and thesauri have long been the domain of the library and information science community. Although historically there have been initiatives towards library style classification of web resources, there remain significant problems with searching and quality judgement of online content. Terminology services can play a key role in opening up access to these valuable resources. By exposing controlled terminologies via a web service, organisations maintain data integrity and version control, whilst motivating external users to design innovative ways to present and utilise their data. We describe the approaches taken in establishing programmatic API’s, then relate our experiences in creating terminology web services and associated client interface components, in particular for the archaeology domain (STAR project) and consider the case for more specialised services for different kinds of controlled vocabular
Petri Net Controlled Finite Automata
No full textWe present a generalization of finite automata using Petri nets as control, called Concurrent Finite Automata for short. Several modes of acceptance, defined by final markings of the Petri net, are introduced, and their equivalence is shown. The class of languages obtained by *-free concurrent finite automata contains both the class of regular sets and the class of Petri net languages defined by final marking, and is contained in the class of context-sensitive languages
Mining of miRNAs and potential targets from gene oriented clusters of transcripts sequences of the anti-malarial plant, Artemisia annua
No full textmiRNAs involved in the biosynthesis of artemisinin, an anti-malarial compound form the plant Artemisia annua, have been identified using computational approaches to find conserved pre-miRNAs in available A. annua UniGene collections. Eleven pre-miRNAs were found from nine families. Targets predicted for these miRNAs were mainly transcription factors for conserved miRNAs. No target genes involved in artemisinin biosynthesis were found. However, miR390 was predicted to target a gene involved in the trichome development, which is the site of synthesis of artemisinin and could be a candidate for genetic transformation aiming to increase the content of artemisinin. Phylogenetic analyses were carried out to determinate the relation between A. annua and other plant pre-miRNAs: the pre-miRNA-based phylogenetic trees failed to correspond to known phylogenies, suggesting that pre-miRNA primary sequences may be too variable to accurately predict phylogenetic relations
Artificial microRNAs (amiRNAs) engineering – on how microRNA-based silencing methods have affected current plant silencing research
No full textIn recent years, endogenous microRNAs have been described as important regulators of gene expression in eukaryotes. Artificial microRNAs (amiRNAs) represent a recently developed miRNA-based strategy to silence endogenous genes. amiRNAs can be created by exchanging the miRNA/miRNA(*) sequence within a miRNA precursor with a sequence designed to match the target gene, this is possible as long as the secondary RNA structure of the precursor is kept intact. In this review, we summarize the basic methodologies to design amiRNAs and detail their applications in plants genetic functional studies as well as their potential for crops genetic improvement