Ivan Olier

Dr. Ivan Olier

Data Science Research Centre, Liverpool John Moores University, Liverpool, UK
orcid

Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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18 June 2014 in PLOS ONE
Verified
Journal Article
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DSDavid A. Springate
David A. Springate
EKEvangelos HEATHER Kontopantelis
Evangelos HEATHER Kontopantelis
DADarren M. Ashcroft
Darren M. Ashcroft
IOIvan Olier
Ivan Olier
RPRosa Parisi
Rosa Parisi
DRDavid Reeves
David Reeves
Lists of clinical codes are the foundation for research undertaken using electronic medical records (EMRs). If clinical code lists are not available, reviewers are unable to determine the validity of research, full study replication is impossible, researchers are unable to make effective comparisons between studies, and the construction of new code lists is subject to much duplication of effort. Despite this, the publication of clinical codes is rarely if ever a requirement for obtaining grants, validating protocols, or publishing research. In a representative sample of 450 EMR primary research articles indexed on PubMed, we found that only 19 (5.1%) were accompanied by a full set of published clinical codes and 32 (8.6%) stated that code lists were available on request. To help address these problems, we have built an online repository where researchers using EMRs can upload and download lists of clinical codes. The repository will enable clinical researchers to better validate EMR studies, build on previous code lists and compare disease definitions across studies. It will also assist health informaticians in replicating database studies, tracking changes in disease definitions or clinical coding practice through time and sharing clinical code information across platforms and data sources as research objects.

1 July 2020 in Water
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Salah L. ZubaidiSalah L. Zubaidi
Salah L. Zubaidi
Sandra Ortega-MartorellSandra Ortega-Martorell
Sandra Ortega-Martorell
LALubna R. Al-Ameer
Lubna R. Al-Ameer
IOIvan Olier
Ivan Olier
Khalid HashimKhalid Hashim
Khalid Hashim
Rafid AlkhaddarRafid Alkhaddar
Rafid Alkhaddar
The proper management of a municipal water system is essential to sustain cities and support the water security of societies. Urban water estimating has always been a challenging task for managers of water utilities and policymakers. This paper applies a novel methodology that includes data pre-processing and an Artificial Neural Network (ANN) optimized with the Backtracking Search Algorithm (BSA-ANN) to estimate monthly water demand in relation to previous water consumption. Historical data of monthly water consumption in the Gauteng Province, South Africa, for the period 2007–2016, were selected for the creation and evaluation of the methodology. Data pre-processing techniques played a crucial role in the enhancing of the quality of the data before creating the prediction model. The BSA-ANN model yielded the best result with a root mean square error and a coefficient of efficiency of 0.0099 mega liters and 0.979, respectively. Moreover, it proved more efficient and reliable than the Crow Search Algorithm (CSA-ANN), based on the scale of error. Overall, this paper presents a new application for the hybrid model BSA-ANN that can be successfully used to predict water demand with high accuracy, in a city that heavily suffers from the impact of climate change and population growth.

15 December 2015 in BMJ Open
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SRSiobhan Reilly
Siobhan Reilly
IOIvan Olier
Ivan Olier
CPClaire Planner
Claire Planner
TDTim Doran
Tim Doran
DRDavid Reeves
David Reeves
EKEvangelos HEATHER Kontopantelis
Evangelos HEATHER Kontopantelis
Objectives Little is known about the prevalence of comorbidity rates in people with severe mental illness (SMI) in UK primary care. We calculated the prevalence of SMI by UK country, English region and deprivation quintile, antipsychotic and antidepressant medication prescription rates for people with SMI, and prevalence rates of common comorbidities in people with SMI compared with people without SMI. Design Retrospective cohort study from 2000 to 2012. Setting 627 general practices contributing to the Clinical Practice Research Datalink, a UK primary care database. Participants Each identified case (346 551) was matched for age, sex and general practice with 5 randomly selected control cases (1 732 755) with no diagnosis of SMI in each yearly time point. Outcome measures Prevalence rates were calculated for 16 conditions. Results SMI rates were highest in Scotland and in more deprived areas. Rates increased in England, Wales and Northern Ireland over time, with the largest increase in Northern Ireland (0.48% in 2000/2001 to 0.69% in 2011/2012). Annual prevalence rates of all conditions were higher in people with SMI compared with those without SMI. The discrepancy between the prevalence of those with and without SMI increased over time for most conditions. A greater increase in the mean number of additional conditions was observed in the SMI population over the study period (0.6 in 2000/2001 to 1.0 in 2011/2012) compared with those without SMI (0.5 in 2000/2001 to 0.6 in 2011/2012). For both groups, most conditions were more prevalent in more deprived areas, whereas for the SMI group conditions such as hypothyroidism, chronic kidney disease and cancer were more prevalent in more affluent areas. Conclusions Our findings highlight the health inequalities faced by people with SMI. The provision of appropriate timely health prevention, promotion and monitoring activities to reduce these health inequalities are needed, especially in deprived areas.

1 May 2021 in European Journal of Pharmaceutical Sciences
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QTQuynh Ta
Quynh Ta
JTJessica Ting
Jessica Ting
SHSophie Harwood
Sophie Harwood
NBNicola Browning
Nicola Browning
ASAlan Simm
Alan Simm
RARaida Al-Kassas
Raida Al-Kassas

7 November 2008 in Magnetic Resonance Materials in Physics, Biology and Medicine
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JGJuan Miguel Garcia-Gomez
Juan Miguel Garcia-Gomez
JLJan Luts
Jan Luts
Margarida Julià-SapéMargarida Julià-Sapé
Margarida Julià-Sapé
PKPatrick Krooshof
Patrick Krooshof
STSalvador Tortajada
Salvador Tortajada
MRMontserrat Robles
Montserrat Robles
Automatic brain tumor classification by MRS has been under development for more than a decade. Nonetheless, to our knowledge, there are no published evaluations of predictive models with unseen cases that are subsequently acquired in different centers. The multicenter eTUMOUR project (2004–2009), which builds upon previous expertise from the INTERPRET project (2000–2002) has allowed such an evaluation to take place. A total of 253 pairwise classifiers for glioblastoma, meningioma, metastasis, and low-grade glial diagnosis were inferred based on 211 SV short TE INTERPRET MR spectra obtained at 1.5 T (PRESS or STEAM, 20–32 ms) and automatically pre-processed. Afterwards, the classifiers were tested with 97 spectra, which were subsequently compiled during eTUMOUR. In our results based on subsequently acquired spectra, accuracies of around 90% were achieved for most of the pairwise discrimination problems. The exception was for the glioblastoma versus metastasis discrimination, which was below 78%. A more clear definition of metastases may be obtained by other approaches, such as MRSI + MRI. The prediction of the tumor type of in-vivo MRS is possible using classifiers developed from previously acquired data, in different hospitals with different instrumentation under the same acquisition protocols. This methodology may find application for assisting in the diagnosis of new brain tumor cases and for the quality control of multicenter MRS databases.

22 December 2017 in Machine Learning
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IOIvan Olier
Ivan Olier
NSNoureddin Sadawi
Noureddin Sadawi
GBG. Richard Bickerton
G. Richard Bickerton
JVJoaquin Vanschoren
Joaquin Vanschoren
CGCrina Grosan
Crina Grosan
RKRoss D. King
Ross D. King
We investigate the learning of quantitative structure activity relationships (QSARs) as a case-study of meta-learning. This application area is of the highest societal importance, as it is a key step in the development of new medicines. The standard QSAR learning problem is: given a target (usually a protein) and a set of chemical compounds (small molecules) with associated bioactivities (e.g. inhibition of the target), learn a predictive mapping from molecular representation to activity. Although almost every type of machine learning method has been applied to QSAR learning there is no agreed single best way of learning QSARs, and therefore the problem area is well-suited to meta-learning. We first carried out the most comprehensive ever comparison of machine learning methods for QSAR learning: 18 regression methods, 3 molecular representations, applied to more than 2700 QSAR problems. (These results have been made publicly available on OpenML and represent a valuable resource for testing novel meta-learning methods.) We then investigated the utility of algorithm selection for QSAR problems. We found that this meta-learning approach outperformed the best individual QSAR learning method (random forests using a molecular fingerprint representation) by up to 13%, on average. We conclude that meta-learning outperforms base-learning methods for QSAR learning, and as this investigation is one of the most extensive ever comparisons of base and meta-learning methods ever made, it provides evidence for the general effectiveness of meta-learning over base-learning.