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2. Operational Research: Methods and Applications

Author

Petropoulos, Fotios, Laporte, Gilbert, Aktas, Emel, Alumur, Sibel A., Archetti, Claudia, Ayhan, Hayriye, Battarra, Maria, Bennell, Julia A., Bourjolly, Jean-Marie, Boylan, John E., Breton, Michèle, Canca, David, Charlin, Laurent, Chen, Bo, Cicek, Cihan Tugrul, Cox Jr, Louis Anthony, Currie, Christine S. M., Demeulemeester, Erik, Ding, Li, Disney, Stephen M., Ehrgott, Matthias, Eppler, Martin J., Erdoğan, Güneş, Fortz, Bernard, Franco, L. Alberto, Frische, Jens, Greco, Salvatore, Gregory, Amanda J., Hämäläinen, Raimo P., Herroelen, Willy, Hewitt, Mike, Holmström, Jan, Hooker, John N., Işık, Tuğçe, Johnes, Jill, Kara, Bahar Y., Karsu, Özlem, Kent, Katherine, Köhler, Charlotte, Kunc, Martin, Kuo, Yong-Hong, Lienert, Judit, Letchford, Adam N., Leung, Janny, Li, Dong, Li, Haitao, Ljubić, Ivana, Lodi, Andrea, Lozano, Sebastián, Lurkin, Virginie, Martello, Silvano, McHale, Ian G., Midgley, Gerald, Morecroft, John D. W., Mutha, Akshay, Oğuz, Ceyda, Petrovic, Sanja, Pferschy, Ulrich, Psaraftis, Harilaos N., Rose, Sam, Saarinen, Lauri, Salhi, Said, Song, Jing-Sheng, Sotiros, Dimitrios, Stecke, Kathryn E., Strauss, Arne K., Tarhan, İstenç, Thielen, Clemens, Toth, Paolo, Berghe, Greet Vanden, Vasilakis, Christos, Vaze, Vikrant, Vigo, Daniele, Virtanen, Kai, Wang, Xun, Weron, Rafał, White, Leroy, Van Woensel, Tom, Yearworth, Mike, Yıldırım, E. Alper, Zaccour, Georges, and Zhao, Xuying

Subjects
Mathematics - Optimization and Control
Abstract

Throughout its history, Operational Research has evolved to include a variety of methods, models and algorithms that have been applied to a diverse and wide range of contexts. This encyclopedic article consists of two main sections: methods and applications. The first aims to summarise the up-to-date knowledge and provide an overview of the state-of-the-art methods and key developments in the various subdomains of the field. The second offers a wide-ranging list of areas where Operational Research has been applied. The article is meant to be read in a nonlinear fashion. It should be used as a point of reference or first-port-of-call for a diverse pool of readers: academics, researchers, students, and practitioners. The entries within the methods and applications sections are presented in alphabetical order. The authors dedicate this paper to the 2023 Turkey/Syria earthquake victims. We sincerely hope that advances in OR will play a role towards minimising the pain and suffering caused by this and future catastrophes.

Published
2023
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7. Operational research: methods and applications

Author

Petropoulos, Fotios, Laporte, Gilbert, Archetti, Claudia, Ayhan, Hayriye, Battarra, Maria, Bennell, Julia A., Boylan, John E., Breton, Michèle, Canca, David, Charlin, Laurent, Chen, Bo, Cicek, Cihan Tugrul, Jr, Louis Anthony Cox, Currie, Christine S. M., Demeulemeester, Erik, Ding, Li, Disney, Stephen M., Ehrgott, Matthias, Eppler, Martin J., Erdoğan, Güneş, Fortz, Bernard, Franco, L. Alberto, Frische, Jens, Greco, Salvatore, Gregory, Amanda J., Hämäläinen, Raimo P., Herroelen, Willy, Hewitt, Mike, Holmström, Jan, Hooker, John N., Işık, Tuğçe, Johnes, Jill, Kara, Bahar Y., Karsu, Özlem, Kent, Katherine, Köhler, Charlotte, Kunc, Martin, Kuo, Yong-Hong, Lienert, Judit, Letchford, Adam N., Leung, Janny, Li, Dong, Li, Haitao, Ljubić, Ivana, Lodi, Andrea, Lozano, Sebastián, Lurkin, Virginie, Martello, Silvano, McHale, Ian G., Midgley, Gerald, Morecroft, John D. W., Mutha, Akshay, Oğuz, Ceyda, Petrovic, Sanja, Pferschy, Ulrich, Psaraftis, Harilaos N., Rose, Sam, Saarinen, Lauri, Salhi, Said, Song, Jing-Sheng, Sotiros, Dimitrios, Stecke, Kathryn E., Strauss, Arne K., Tarhan, İstenç, Thielen, Clemens, Toth, Paolo, Berghe, Greet Vanden, Vasilakis, Christos, Vaze, Vikrant, Vigo, Daniele, Virtanen, Kai, Wang, Xun, Weron, Rafał, White, Leroy, Woensel, Tom Van, Yearworth, Mike, Yıldırım, E. Alper, Zaccour, Georges, Zhao, Xuying, Petropoulos, Fotios, Laporte, Gilbert, Archetti, Claudia, Ayhan, Hayriye, Battarra, Maria, Bennell, Julia A., Boylan, John E., Breton, Michèle, Canca, David, Charlin, Laurent, Chen, Bo, Cicek, Cihan Tugrul, Jr, Louis Anthony Cox, Currie, Christine S. M., Demeulemeester, Erik, Ding, Li, Disney, Stephen M., Ehrgott, Matthias, Eppler, Martin J., Erdoğan, Güneş, Fortz, Bernard, Franco, L. Alberto, Frische, Jens, Greco, Salvatore, Gregory, Amanda J., Hämäläinen, Raimo P., Herroelen, Willy, Hewitt, Mike, Holmström, Jan, Hooker, John N., Işık, Tuğçe, Johnes, Jill, Kara, Bahar Y., Karsu, Özlem, Kent, Katherine, Köhler, Charlotte, Kunc, Martin, Kuo, Yong-Hong, Lienert, Judit, Letchford, Adam N., Leung, Janny, Li, Dong, Li, Haitao, Ljubić, Ivana, Lodi, Andrea, Lozano, Sebastián, Lurkin, Virginie, Martello, Silvano, McHale, Ian G., Midgley, Gerald, Morecroft, John D. W., Mutha, Akshay, Oğuz, Ceyda, Petrovic, Sanja, Pferschy, Ulrich, Psaraftis, Harilaos N., Rose, Sam, Saarinen, Lauri, Salhi, Said, Song, Jing-Sheng, Sotiros, Dimitrios, Stecke, Kathryn E., Strauss, Arne K., Tarhan, İstenç, Thielen, Clemens, Toth, Paolo, Berghe, Greet Vanden, Vasilakis, Christos, Vaze, Vikrant, Vigo, Daniele, Virtanen, Kai, Wang, Xun, Weron, Rafał, White, Leroy, Woensel, Tom Van, Yearworth, Mike, Yıldırım, E. Alper, Zaccour, Georges, and Zhao, Xuying

Abstract

Throughout its history, Operational Research has evolved to include methods, models and algorithms that have been applied to a wide range of contexts. This encyclopedic article consists of two main sections: methods and applications. The first summarises the up-to-date knowledge and provides an overview of the state-of-the-art methods and key developments in the various subdomains of the field. The second offers a wide-ranging list of areas where Operational Research has been applied. The article is meant to be read in a nonlinear fashion and used as a point of reference by a diverse pool of readers: academics, researchers, students, and practitioners. The entries within the methods and applications sections are presented in alphabetical order. The authors dedicate this paper to the 2023 Turkey/Syria earthquake victims. We sincerely hope that advances in OR will play a role towards minimising the pain and suffering caused by this and future catastrophes.

Published
2024

9. Operational Research: methods and applications

Author

Petropoulos, Fotios, primary, Laporte, Gilbert, additional, Aktas, Emel, additional, Alumur, Sibel A., additional, Archetti, Claudia, additional, Ayhan, Hayriye, additional, Battarra, Maria, additional, Bennell, Julia A., additional, Bourjolly, Jean-Marie, additional, Boylan, John E., additional, Breton, Michèle, additional, Canca, David, additional, Charlin, Laurent, additional, Chen, Bo, additional, Cicek, Cihan Tugrul, additional, Cox, Louis Anthony, additional, Currie, Christine S.M., additional, Demeulemeester, Erik, additional, Ding, Li, additional, Disney, Stephen M., additional, Ehrgott, Matthias, additional, Eppler, Martin J., additional, Erdoğan, Güneş, additional, Fortz, Bernard, additional, Franco, L. Alberto, additional, Frische, Jens, additional, Greco, Salvatore, additional, Gregory, Amanda J., additional, Hämäläinen, Raimo P., additional, Herroelen, Willy, additional, Hewitt, Mike, additional, Holmström, Jan, additional, Hooker, John N., additional, Işık, Tuğçe, additional, Johnes, Jill, additional, Kara, Bahar Y., additional, Karsu, Özlem, additional, Kent, Katherine, additional, Köhler, Charlotte, additional, Kunc, Martin, additional, Kuo, Yong-Hong, additional, Letchford, Adam N., additional, Leung, Janny, additional, Li, Dong, additional, Li, Haitao, additional, Lienert, Judit, additional, Ljubić, Ivana, additional, Lodi, Andrea, additional, Lozano, Sebastián, additional, Lurkin, Virginie, additional, Martello, Silvano, additional, McHale, Ian G., additional, Midgley, Gerald, additional, Morecroft, John D.W., additional, Mutha, Akshay, additional, Oğuz, Ceyda, additional, Petrovic, Sanja, additional, Pferschy, Ulrich, additional, Psaraftis, Harilaos N., additional, Rose, Sam, additional, Saarinen, Lauri, additional, Salhi, Said, additional, Song, Jing-Sheng, additional, Sotiros, Dimitrios, additional, Stecke, Kathryn E., additional, Strauss, Arne K., additional, Tarhan, İstenç, additional, Thielen, Clemens, additional, Toth, Paolo, additional, Van Woensel, Tom, additional, Berghe, Greet Vanden, additional, Vasilakis, Christos, additional, Vaze, Vikrant, additional, Vigo, Daniele, additional, Virtanen, Kai, additional, Wang, Xun, additional, Weron, Rafał, additional, White, Leroy, additional, Yearworth, Mike, additional, Yıldırım, E. Alper, additional, Zaccour, Georges, additional, and Zhao, Xuying, additional

Published
2023
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18. Improving uptake of simulation in healthcare: User-driven development of an open-source tool for modelling patient flow.

Author

Tyler, Joshua MB, Murch, Ben J, Vasilakis, Christos, and Wood, Richard M

Abstract

Despite the many examples where simulation has successfully demonstrated its capability in modelling patient flow, there is little evidence of enduring widespread use. Bespoke academic projects provide little scope for repeatable practical application and efforts to develop generic reusable solutions have neither clearly identified the end users nor fully appreciated their multifaceted requirements. Influenced by a review of existing findings and recommendations in addition to a customised survey of prospective end users, a set of practical design principles were elicited in guiding development of a new open-source and versatile tool. Capturing variability in arrivals and length of stay as well as the stochastic nature of dynamic delays in patient discharge and transfer, the PathSimR tool can be used to model various user-defined configurations of outpatient and inpatient pathways. In addition to reporting on early use and engagement initiatives to promote the tool, this study also offers a blueprint for how simulation models can be developed and deployed within the healthcare setting. [ABSTRACT FROM AUTHOR]

Published
2023
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23. Exploring financially sustainable initiatives to address out-of-area placements in psychiatric ICUs: a computer simulation study.

Author

Moss, Simon J., Vasilakis, Christos, and Wood, Richard M.

Subjects
*INTENSIVE care units, *COMPUTER simulation, *SAMPLE size (Statistics), *MEDICAL care, *MEDICAL care costs, *HOSPITAL care, *DESCRIPTIVE statistics, *RESEARCH funding, *PSYCHIATRIC hospitals
Abstract

Transferring individuals for treatment outside their geographic area occurs when healthcare demand exceeds local supply. This can result in significant financial cost while impacting patient outcomes and experience. The aim of this study was to assess initiatives to reduce psychiatric intensive care unit (PICU) out-of-area bed placements within a major healthcare system in South West England. Discrete event computer simulation was used to model patient flow across the healthcare system's three PICUs. A scenario analysis was performed to estimate the impact of management plans to decrease admissions and length of stay. The amount of capacity required to minimise total cost was also considered. Without increasing in-area capacity, mean out-of-area bed requirement can be reduced by 25.6% and 19.1% respectively through plausible initiatives to decrease admissions and length of stay. Reductions of 34.7% are possible if both initiatives are employed. Adjusting the in-area bed capacity can also lead to aggregate cost savings. This study supports the likely effectiveness of particular initiatives in reducing out-of-area placements for high-acuity bedded psychiatric care. This study also demonstrates the value of computer simulation in an area that has seen little such attention to date. [ABSTRACT FROM AUTHOR]

Published
2023
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24. An Analysis of Missing Data Treatment Methods and Their Application to Health Care Dataset

Author

Liu, Peng, El-Darzi, Elia, Lei, Lei, Vasilakis, Christos, Chountas, Panagiotis, Huang, Wei, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Dough, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Carbonell, Jaime G., editor, Siekmann, Jörg, editor, Li, Xue, editor, Wang, Shuliang, editor, and Dong, Zhao Yang, editor

Published
2005
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25. On Uncertainty and Data-Warehouse Design

Author

Chountas, Panagiotis, Petrounias, Ilias, Vasilakis, Christos, Tseng, Andy, El-Darzi, Elia, Atanassov, Krassimir T., Kodogiannis, Vassilis, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Dough, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, and Yakhno, Tatyana, editor

Published
2005
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29. Visualizing Opioid-Use Variation in a Pediatric Perioperative Dashboard

Author

Safranek, Conrad W., additional, Feitzinger, Lauren, additional, Joyner, Alice Kate Cummings, additional, Woo, Nicole, additional, Smith, Virgil, additional, Souza, Elizabeth De, additional, Vasilakis, Christos, additional, Anderson, Thomas Anthony, additional, Fehr, James, additional, Shin, Andrew Y., additional, Scheinker, David, additional, Wang, Ellen, additional, and Xie, James, additional

Published
2022
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35. Evaluating the sustainability of complex health system transformation in the context of population ageing: An empirical system dynamics study.

Author

Dural Selcuk, Gozdem and Vasilakis, Christos

Subjects
SYSTEM dynamics, POPULATION aging, LENGTH of stay in hospitals, PATIENT readmissions, SUSTAINABILITY
Abstract

Demographic changes, particularly population ageing, and rising morbidity from chronic conditions contribute to ever-increasing pressures on health and care systems in developed countries. Partly as a response, new models of care and service innovations are being piloted and introduced. However, the effectiveness and sustainability of these complex health system transformations are often not well understood and most modelling studies fail to capture both system configuration and populating dynamics. In this paper, we present a comprehensive system dynamics modelling approach to capture both population ageing and the organisation of the health and care services from a whole system perspective. The development of the model was directly informed by an ambitious care system transformation project designed to offer a different pathway for those patients deemed to be complex. The model input parameters were populated using estimates from empirical data. A series of simulation experiments were conducted to inform the design of the new service and its sustainability. We found that, subject to the model's limitations and assumptions, the new pathway could have a stabilising effect against increasing demand provided hospital readmission fractions and length of stay for complex patients can be managed effectively. [ABSTRACT FROM AUTHOR]

Published
2023
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37. Improving Timeliness in the Neglected Tropical Diseases Preventive Chemotherapy Donation Supply Chain through Information Sharing: A Retrospective Empirical Analysis

Author

Kasparis, Elena, Huang, Yufei, Lin, Bill, and Vasilakis, Christos

Subjects
Health Care, Supply Chain Management, Information Sharing, Neglected Tropical Diseases
Abstract

Background Billions of doses of medicines are donated for mass drug administrations in support of the World Health Organization’s “Roadmap to Implementation,” which aims to control, eliminate, and eradicate Neglected Tropical Diseases (NTDs). The supply chain to deliver these medicines is complex, with fragmented data systems and limited visibility on performance. This study empirically evaluates the impact of an online supply chain performance measurement system, “NTDeliver,” providing understanding of the value of information sharing towards the success of global health programs. Methods Retrospective secondary data was extracted from NTDeliver, which included 1,484 shipments for four critical medicines ordered by over 100 countries between February 28, 2006 and December 31, 2018. We applied statistical regression models to analyze the impact on key performance metrics, comparing data before and after the system was implemented. Findings The results suggest information sharing has a positive impact on three performance indicators: purchase order timeliness (β=1.01, p

Published
2021

40. Population‐level management of type 1 diabetes via continuous glucose monitoring and algorithm‐enabled patient prioritization: Precision health meets population health

Author

Ferstad, Johannes O., primary, Vallon, Jacqueline J., additional, Jun, Daniel, additional, Gu, Angela, additional, Vitko, Anastasiya, additional, Morales, Dianelys P., additional, Leverenz, Jeannine, additional, Lee, Ming Yeh, additional, Leverenz, Brianna, additional, Vasilakis, Christos, additional, Osmanlliu, Esli, additional, Prahalad, Priya, additional, Maahs, David M., additional, Johari, Ramesh, additional, and Scheinker, David, additional

Published
2021
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44. sj-docx-1-mdm-10.1177_0272989X21994035 – Supplemental material for The Value of Triage during Periods of Intense COVID-19 Demand: Simulation Modeling Study

Author

Wood, Richard M., Pratt, Adrian C., Kenward, Charlie, McWilliams, Christopher J., Booton, Ross D., Thomas, Matthew J., Bourdeaux, Christopher P., and Vasilakis, Christos

Subjects
111708 Health and Community Services, 111799 Public Health and Health Services not elsewhere classified, 160807 Sociological Methodology and Research Methods, FOS: Health sciences, FOS: Sociology
Abstract

Supplemental material, sj-docx-1-mdm-10.1177_0272989X21994035 for The Value of Triage during Periods of Intense COVID-19 Demand: Simulation Modeling Study by Richard M. Wood, Adrian C. Pratt, Charlie Kenward, Christopher J. McWilliams, Ross D. Booton, Matthew J. Thomas, Christopher P. Bourdeaux and Christos Vasilakis in Medical Decision Making

Published
2021
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45. Analyst-driven development of an open-source simulation tool to address poor uptake of O.R. in healthcare

Author

Vasilakis, Christos and Wood, Richard

Abstract

Computer simulation studies of health and care problems have been reported extensively in the academic literature, but the one-off research projects typically undertaken have failed to create an enduring legacy of widespread use by healthcare practitioners. Simulation and other modelling tools designed and developed to be used routinely have not fared much better either. Following a review of the literature and a survey of frontline analysts in the UK NHS, we found that one reason for this is because simulation tools have, to date, not been developed with the requirements of the end-user in the heart of the development process. Starting with a thorough needs assessment of NHS based healthcare analysts, this study outlines a set of practical design principles to guide development of simulation software tool for conducting patient flow simulation studies. The overall requirement is that patient flow be modelled over a number of inter-connected points of delivery while capturing the stochastic nature of patient arrivals and hospital length of stay, as well as the dynamic delays to patient discharge and transfer of care between different points of care delivery. In ensuring a cost-free solution that is both versatile and user-friendly, and coded in an increasingly popular language among the envisaged end users, the tool was implemented is the R programming language and software environment, with the user interface implemented in the interactive R-Shiny application. The talk will provide an overview of the project lifecycle including an illustrative example of an empirical simulation study concerning the centralisation of an acute stroke pathway.

Published
2020

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