Operational Research Society Research Articles

Operational research in seven decades

This paper is an account and reflection on the author’s engagement with operational research (OR) starting in the 1960s with work in the glass industry coinciding with a PhD at Lancaster and a first encounter with the professional membership debate. The 1970s included a brief encounter with stochastic programming, soft OR which recurred throughout the decades, and the start of research into strategy support. The latter continued in the 80s and beyond and work on data envelopment analysis (DEA) began. In the 1990s, a strong DEA team was built at Warwick, and the author led the development of the OR Society’s fellowship scheme. In the 2000s a group met regularly at Warwick focussing on strategic development and leading to a book on strategy support and editing of the European Journal of Operational Research (EJOR) began. In the 2010s editing continued and work began on the contribution of the founders of OR to soft OR and practice. Editing wound down in the 2020s and the founders paper was published in the journal Operations Research.

Parameter Estimation and Testing for the Doubly Geometric Process with Lognormal Distribution: Application to Bladder Cancer Patients’ Data

The geometric process (GP) has been widely utilized as a stochastic monotone model in the fields of probability and statistics. However, its practical application is often limited by certain assumptions. To address this, [Wu (2018). Doubly geometric process and applications. Journal of the Operational Research Society, 69(1), 66–67] introduced the doubly geometric process (DGP) as an extension of the GP model, relaxing some of its assumptions. Due to its ability to overcome the limitations of the GP model, the DGP has gained significant popularity in recent times. This study focuses on the parameter estimation problem for the DGP when the distribution of the first interarrival time follows a lognormal distribution with parameters [Formula: see text] and [Formula: see text]. We employ the maximum likelihood method to obtain estimates for both the model parameters and the distribution parameters. Additionally, we investigate the asymptotic joint distribution and statistical properties such as asymptotic unbiasedness and consistency of the estimators. Furthermore, we propose a novel test procedure to distinguish between the GP and DGP models. To assess the performance of the estimators and the proposed test procedure, we conduct a simulation study involving various sample sizes and parameter values. Finally, we present an application of the developed methods in fitting data from bladder cancer patients.

Discrete‐event simulation is still alive and strong: evidence from bibliometric performance evaluation of research during COVID‐19 global health pandemic

AbstractDuring the Annual Operational Research Society Simulation Workshop in Worchester, UK, in 2010, a panel discussion entitled “discrete‐event simulation (DES) is dead, long live agent‐based simulation (ABS)!” was held. Subsequent debates on the topic have captured the interest of many simulation professionals and researchers. This study lends credence to the discourse with evidence. In January 2020, a global health crisis named coronavirus disease (COVID‐19) occurred, infecting and killing millions of people globally, leading to community lockdowns and travel restrictions, and bringing the world to a standstill. Scientists scrambled for quick, practical solutions to stem the tide. Operational research (OR) and management science (MS) techniques, including modeling and simulation, provide effective methods to make COVID‐19 infection forecasts, assign/optimize intensive care unit beds, initiate healthcare management/control strategies, and decision‐making. The global pandemic problems offer an opportunity to evaluate the discourse on DES's continuous relevance and potency as an OR/MS technique. Utilizing bibliometric performance evaluation and text analytics of publications addressing various COVID‐19 pandemic problems, the results show an extensive use, relevance, and impact of the DES technique across multidisciplinary domains, including medical/healthcare, social and behavioral sciences, business, molecular biosciences, and more. The intellectual structure highlights strong multidisciplinary collaboration among sources in decision sciences, healthcare, natural, behavioral, and social sciences. The social network analysis of the publications shows the contributions and collaborations among authors, institutions, and countries. The study demonstrates that DES is still alive and robust, notwithstanding the hype about ABS.

Military Operations Research Society (MORS) Oral History Project Interview of Dr. Mark T. Lewellyn

Military Operations Research Society (MORS) Oral History Project Interview of Dr. Mark T. Lewellyn

Military Operations Research Society (MORS) Oral History Project Interview of Dr. Willie J. McFadden II, FS

Military Operations Research Society (MORS) Oral History Project Interview of Dr. Willie J. McFadden II, FS

Special Issue on “Logistics Optimization for Social Good”

The International Transactions in Operational Research (ITOR) will publish a special issue dedicated to “Logistics Optimization for Social Good”. The world and the population are constantly changing, and these changes have been more pronounced during the last decades. High pollution, increasing aging population, frequent diseases and pandemics, depopulation of rural areas and overpopulation in cities, hunger and shortage in developing countries, are some of the main challenges affecting our current and future situation. Around these ideas there are many logistics solutions to consider on a day-to-day and strategic basis, which can bring many benefits to the societies if they are properly advanced. Accordingly, there is a growing interest to ensure that current and future AI and Optimization research provide these logistics solutions for better crisis response, equality and inclusion, economic empowerment, hunger and shortage response, healthcare, or environmental sustainability, i.e., for social good. This will result in advances in both theoretical and practical aspects as well as technical innovations in several logistics sectors such as emergency logistics, humanitarian logistics, healthcare logistics, etc. In this context, with the aim of reflecting and reporting on the latest research and developments in the interplay between logistics for social good and optimization, we propose this special issue entitled “Logistics Optimization for Social Good”. The main goal of this special issue is to bring and comprehensively collect cutting-edge research and recent advances in AI and Optimization to promote and foster logistics for social good. This issue will provide readers with high-quality contributions exploring and dealing with optimization problems in the field of logistics while discussing advanced methods considering social good. Examples involve the joint use of machine learning and mathematical programming, integrating information systems with optimization algorithms, theoretical or empirical studies in modern operations research, developing truly-brained systems to support logistics decisions, etc. As it can be seen, the special issue will contribute to the literature with relevant theoretical and practical works advancing the progress of operations research and artificial intelligence towards logistics for social good. This call for papers is open to the entire community of researchers and practitioners and we encourage any submissions that fit in the scope of this special issue. Authors of selected works from the 13th International Conference on Computational Logistics (ICCL 2022) will be invited to submit an extended version of their ICCL 2022 accepted papers to this special issue. Each paper will be peer-reviewed according to the editorial policy of ITOR (http://www3.interscience.wiley.com/journal/118505725/home), published by the International Federation of Operational Research Societies – IFORS. Papers should be original, unpublished, and not currently under consideration for publication elsewhere. Manuscripts should be prepared according to the instructions to authors that can be found on the journal homepage. Authors should upload their contributions using the submission site http://mc.manuscriptcentral.com/itor, indicating in their cover letter that the paper is intended for this special issue and listing the novel contributions considering related literature. The deadline for submissions is March 12, 2023. Other inquiries should be sent directly to any of the Guest Editors in charge of this issue: Jesica de Armas ([email protected]), Helena Ramalhinho ([email protected]), and Stefan Voß ([email protected]).

RETRACTED ARTICLE: A nonanticipatory policy for stochastic seru scheduling problems

We, the Editors and Publisher of Journal of the Operational Research Society, have retracted the following article: Zhang, Z., Gong, X., Song, X., Yin, Y., Lev, B., & Zhou, X. (2023). A nonanticipatory policy for stochastic seru scheduling problems. Journal of the Operational Research Society, 1–12. https://doi.org/10.1080/01605682.2023.2182723. Since publication, significant concerns have been raised about the fact that this article appears to have substantial overlap with the following articles, which were not cited or referenced. Skutella, M., Sviridenko, M., & Uetz, M. (2016). Unrelated Machine Scheduling with Stochastic Processing Times, Mathematics of Operations Research, 41(3), 851–864. https://doi.org/10.1287/moor.2015.0757. Uetz, M. (2003). When greediness fails: examples from stochastic scheduling, Operations Research Letters, 31(6), 413–419. https://doi.org/10.1016/S0167-6377(03)00047-6 Subsequent to investigation, and communication with the authors, we have also been informed by the first corresponding author that the co-authors were not consulted on the decision to submit to the Journal of the Operational Research Society, nor on the submission of the revised manuscript. The first corresponding author also highlighted inaccuracies in the methodology, specifically the omission of the Worker element extension and the improper application of the model’s extension from discrete to continuous time, both of which were important to the claimed contribution of the article. The authors have agreed with the decision to retract the article. We have been informed in our decision-making by our Editorial Policies and the COPE guidelines. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as “Retracted”.

Upcoming Conferences of Interest to the AHP/ANP Community

There are three upcoming conferences that would be beneficial for the AHP/ANP community. The first conference is “The 23rd Conference of the International Federation of Operational Research Societies”, IFORS2023 STGO to be held in Santiago, Chile, July 10-14, 2023. Second, the INFORMS Annual Conference will be held in Phoenix, Arizona, USA, October 15-18, 2023. Phoenix is a popular location with INFORMS members. We are expecting some AHP/ANP and extensions scholars to participate in this conference. I am planning to invite our AHP/ANP colleagues from all over the world. In the scientific program, there is a cluster for Multiple Criteria Decision Analysis, in which there will be at least one AHP/ANP invited session: AHP/ANP and extensions (Organized by Birsen Karpak, Ilker Topcu) Last, but not least, is the MCDM 2024 conference. The Tunisian Decision Aid Society is organizing this international conference on Multiple Criteria Decision Making which will be held in Hammamet, Tunisia, June 2-7, 2024.

Celebrating 50-years of OR in South Africa – a Bibliometric Analysis of contributions to International OR Literature

The Operations Research Society of South Africa (ORSSA), the first Operations Research (OR) society in Africa, celebrated its 50th anniversary at its annual conference in 2019. To commemorate the occasion a book, covering the history of the society, was launched at the conference. One area that was not covered in this book was the contribution of South Africans to the international OR literature. This paper endeavors to fill that void through a bibliographic analysis of papers published by South Africans over the 50-year period. A list of over 100 journals were used for this analysis. General empirical results are derived while a visual analysis of top author research networks is presented. The analysis demonstrates the contribution to the international OR/MS knowledge base of a small but vibrant national OR society at the most southern point of Africa.

Generalized quick-switch sampling systems indexed by Taguchi capability with record traceability

Acceptance sampling plans of variable measurements quantified by process capability index have become compelling because they can validate how well the upstream lots (process) fit the downstream high-yield requirements in a more discriminatory and economic way. Recent research has accomplished two contrasting systems of quick-switch sampling (VQSS) based on the Taguchi capability index, namely acceptance criterion-switching VQSS (Balamurali and Usha, 2019, published in Journal of the Operational Research Society) and sample size-switching (Wang and Wu, 2021, published in Computers & Industrial Engineering) VQSS. Both studies, nonetheless, lacked in discerning the system’s inspection strengths and weaknesses, nor investigated their joint performance regarding sampling efficiency and sensitivity towards abrupt deviation of the process capability. Moreover, for a sequential lot-inspection process, their simplified mathematical formulation has overlooked the importance of lot-and-sample identification in the supply chain. To forward improvements, we develop a generalized VQSS (GVQSS) system with lot-and-sample records traceability. The GVQSS system activates the concurrent changes of sample size and acceptance criterion based on the past result for lot disposition. It can also accommodate two existing VQSS systems. Additionally, an R-Shiny interactive web app is constructed for practitioners to easily acquire the optimal criteria of VQSS systems. These advancements enable the GVQSS to deal with different phases of supplier–buyer partnerships. Finally, we demonstrate how to apply the GVQSS system through a real-world case.

Airline OR Innovations Soar During COVID-19 Recovery

The Airline Group of the International Federation of Operational Research Societies (AGIFORS) held four conferences during May to July 2021 that focused on how COVID-19 was impacting and reshaping the airline industry. Dozens of airline representatives from around the world spoke about how fundamental changes in passenger demand and booking patterns are reshaping the airline industry and driving innovation and research needs. Customers are booking much closer to departure and are canceling or exchanging their tickets more frequently than before COVID-19. Volatility in demand has increased as travel restrictions change and borders reopen. Consequently, greater uncertainty in demand forecasts used as inputs to optimization algorithms is motivating the need for new approaches. Revenue management and scheduling departments are innovating how they predict market sizes and exploring ways to use new data sources or historic bookings in forecasting models. Scheduling and operations departments are making many more flight-cancellation and equipment-swap decisions one to three days from flight departure, which is changing the role of recovery planning. New urgency exists within crew to design duties and rosters that are robust to ever-evolving schedules. Across functional areas, the increasing emphasis is to develop integrated solutions that jointly optimize schedules, crew pairings, and crew rosters for demand forecasts that are uncertain at the time rosters are published. This paper describes how these changes are reshaping the airline industry during COVID-19, explains why short lead times for bookings and uncertainty in demand volumes are expected to remain after COVID-19, and describes how the airline industry is innovating and developing new operations research approaches for handling uncertain and volatile demand.

Celebrating the 10th simulation workshop: The story of the conference series

ABSTRACT March 2021 saw the running of the 10th Operational Research Society Simulation Workshop (SW), albeit delayed by a year due to the Covid-19 pandemic. It is over 20 years since the planning commenced for the very first SW which took place in Birmingham in March 2002. To mark this occasion, this article presents a short history of the conference including the events that led up to the first conference, details of the first SW, a summary of all 10 SWs, and how all this led to the creation of the Journal of Simulation. As founders of the conference series we provide our personal reflections on these events.

Military Operations Research Society (MORS) Oral History Project: Interview of Mr. Edward A. “Ted” Smyth, FS

Military Operations Research Society (MORS) Oral History Project: Interview of Mr. Edward A. “Ted” Smyth, FS

Military Operations Research Society (MORS) Oral History Project Interview of Vice Admiral Ronald A. Route

Military Operations Research Society (MORS) Oral History Project Interview of Vice Admiral Ronald A. Route

Military Operations Research Society (MORS) Oral History Project: Interview of Dr. Eileen A. Bjorkman

Military Operations Research Society (MORS) Oral History Project: Interview of Dr. Eileen A. Bjorkman

A Matheuristic Algorithm for the Inventory Routing Problem

This work addresses a challenging inventory routing problem that arises from a practical application faced by air-product companies, including Air Liquide. Given its computational complexity and industrial importance, this problem (denoted as IRP-Challenge2016) was presented as the topic of the French Operational Research and Decision Support Society/European Operational Research Society (ROADEF/EURO) Challenge 2016. The IRP-Challenge2016 seeks an optimal delivery schedule to minimize the unit distribution cost, while satisfying various hard constraints. It involves a single product, a heterogeneous fleet, heterogeneous drivers, multiperiods, a deterministic consumption forecast, and time-window constraints. We present a new mathematical formulation of the problem and introduce a matheuristic algorithm that integrates a local search-based metaheuristic with mathematical programming. Our algorithm combines mixed integer programming and linear programming as slave methods to optimize timing and delivery and embeds these procedures within a multineighborhood search metaheuristic to adjust routes. The method extends and enhances a preliminary version of our algorithm, which ranked third in the final round of the ROADEF/EURO Challenge 2016. Computational results for 20 challenge benchmark instances demonstrate the value of the proposed algorithm in terms of both effectiveness and efficiency with respect to the results reported in the competition. We additionally analyze several key components of our matheuristic to gain an insight into its operation.

The current state of OR in Africa

All the efforts over the last 20 years, by both the International Federation of Operations Research Societies and The Association of European Operational Research Societies (EURO), to promote operations research in Africa have not delivered the desired results. Of the 54 countries in Africa only four are at present members of IFORS with another five that are associated with a formal operations research society. Nevertheless, Africa remains a fertile ground for operations research in many respects. The discipline is ideally suited for addressing many of the multitudes of complex problems facing the continent. In addition, there are countries where academic institutions are offering operations research courses in their curriculum resulting in a growing number of graduates that are familiar with operations research. It should thus be feasible for these graduates and the academics, in the respective countries, to establish operations research societies. This paper endeavours to get a sense of what the current state is of operations research in the continent. From this it is possible to identify countries where there are more than enough activities to justify the establishment of formal professional operations research societies. It is concluded that the current four IFORS member societies can be extended to twenty over the next 3–5 years. The recent establishment of the African Federation of Operational Research Societies has been a major step towards achieving this goal and growth as well as promoting the use of operations research.

A new hierarchical approach to requirement analysis of problems in automated planning

The use of Knowledge Engineering (KE) processes to analyze and configure domains in automated planning is becoming more appealing since it was noticed that this issue could make a difference to solve real problems. The contrast between a generic domain independent approach, taken as canonical in AI, and alternative processes that include knowledge engineering – eventually adding specific knowledge – has been discussed by Computer and Engineering communities. A big impact has been noticed mainly in the early phase of requirement analysis when KE approach is normally introduced. Requirement analysis is responsible for carrying out the Knowledge modeling of both problem and work domains, which is a key issue to guide different planner algorithms to come out with efficient solutions. Also, there is the scalability issue that appear in most real problems. To face that, hierarchical methods played an important hole in the history of planning and inspired several solutions since the proposal of NONLIN in the 70’s. Since then, the idea of associating hierarchical relational nets with partial ordered actions has prevailed when large systems were considered. However, there is still a gap between the hierarchical approach and the state of art of requirements analysis to allow features anticipated by KE approach to really appear in the requirements of a planning process. This paper proposes a pathway to solve this gap starting with requirements elicitation represented first in the conventional semi-formal (diagrammatic) language – UML – that is translated to Hierarchical Petri Nets (HPNs) by a new enhanced algorithm. The proposed process was installed in a software tool – developed by one of the authors – that analyzes the performance of the KE planning model: itSIMPLE (Integrated Tools Software Interface for Modeling Planning Environment). This tool was initially designed to use classic Place/Transition nets and an old version of UML (2.1). It is now enhanced to use UML 2.4 and a hierarchical Petri Net extension, also developed by the authors. Realistic examples illustrate the process which is now being applied to larger problems related to the manufacturing of car sequencing domain, one of challenge of ROADEF 2005 (French Operations Research & Decision Support Society). Finally, we consider the possibility to introduce another approach to the KE process by using KAOS (Keep All Object Satisfied) to make the planning design more accurate.

Dancing links for optimal timetabling

Military Operations Research Society. All rights reserved. Algorithms for timetabling solutions typically involve sequential allocation of students to courses and resources as the algorithm unfolds. Most current solutions, to this end, commonly use some form of stochastic optimization. In this paper, we propose a novel paradigm for optimal timetabling that comprises two distinct phases. First, we enumerate all feasible course schedules, along with their costs, using a modified implementation of Knuth’s Dancing Links technique for the exact cover problem. To our knowledge, the only prior use of this implementation has been to solve games such as Sudoku and N-Queens. Once the list of all solutions that satisfy prerequisite and time-clash constraints is generated, the second phase applies a standard deterministic optimization to allocate students to these feasible schedules. This method has been applied to a real complex timetabling problem in the Royal Australian Navy helicopter aircrew training program. The results are compared, in terms of computational time, to an exhaustive best practice backtracking algorithm for generating a complete set of feasible schedules, as well as to a pure integer linear programming solution for generating schedules and allocating students to schedules.

Whither is problem structuring methods (PSMs)?

"Whither is problem structuring methods (PSMs)?." Journal of the Operational Research Society, 70(8), pp. 1391–1392