OR contributions to flexibility improvement in production/inventory systems

Recently the notion of flexibility (especially with respect to Flexible Manufacturing Systems) has attracted considerable attention of OR workers. The majority of the contributions is focussed on operational aspects of production systems. A further very important issue concerns the design of production systems and investment decisions with respect to these systems.The aim of this paper is to illustrate how OR models can contribute to quantify effects of, for instance, investment in set-up time reduction or investment in supply leadtime reduction on logistic performance of production systems. Of course there are many more opportunities to improve logistic performance. The approach in this paper offers the opportunity to quantify the integral effects of these improvements and shows the direction for logistic innovation. In this way both design of production systems and quality of related investment decisions can be improved significantly.Some simple examples are worked out in order to illustrate the ideas and to give impetus for further research in this field.     

Towards user-friendly OR: a Chinese experience

In contemporary China, user-friendliness has become not only a necessity for the success of OR projects but also a must for the survival of OR workers. This paper presents an approach that, based upon insights from Chinese thought as well as OR/MS experience in the Chinese context since the 1950s, can be useful for improving user-friendliness in the OR process. The paper also reports a real-world project in which OR workers pursue the user-friendliness of their work under the guidance of these insights and approach. A cultural analysis suggests that, while user-friendly OR is a universal concern, the Eastern and Western ways of tackling the issue appear different. The paper concludes that, in reality, Chinese OR workers must enhance their vision and skills so as to solve sociotechnical problems with diverse methods and do so in a user-friendly manner.     

Operational research and ethics: A literature review

Any human activity raises ethical questions, questions about ‘good’ and ‘right’ ways to act and to live; or to put it differently, questions of values and responsibility. From its inception operational research (OR) has engaged with such questions in terms of professional behavior, the handling of preferences in OR, the societal role of OR, the process of OR intervention and the content of OR analysis. As a result, analytical methods and processes have been developed to help clients explore the ethical dimension of their decisions. The paper reviews the literature published in selected OR journals (Management Science; Operations Research; Interfaces; the European Journal of Operational Research; the Journal of the Operations Research Society; Omega; International Transactions in Operational Research; the Journal of Multi-Criteria Decision Analysis), organizing it along the lines of OR’s core competences. The review identifies a number of significant research programmes that are well established and are being energetically pursued; the research findings are being applied to a wide range of important issues. Ethical questions lie at the heart of the great governmental and commercial issues of the day: economic growth and instability; inequality and injustice; environmental degradation and sustainability. They also lie at the heart of the more mundane decisions of day-to-day OR. ‘Ethics’ therefore provides a useful focus for OR both in terms of raising the awareness of all concerned and in providing a theme for research. As a result of the review some research questions are suggested. There is much of interest, much to do.     

To charge or not to charge?

Discussions on the success or failure of OR practice tend to focus on specific case studies which often highlight major dilemmas that face OR professionals: Model robustness, simplicity vs complexity, optimising vs satisficing, conflict between criteria, who is the ‘client’?, and so on. But above all, the following issues predominate: Should OR be concerned with tactical or strategic problems? Where should it be placed in the organisational structure and who should it report to? These issues inevitably raise the questions of accountability, coupled with that of charging for OR services. It is this issue in particular, whether to charge or not to charge for OR services, that the paper seeks to explore.     

The Future of Operational Research is Past

After a brief discussion of the diagnoses of others of OR's ailments, a detailed examination is made of the impacts of academic OR on its practice. These impacts include the dispersion of OR in organizations, the displacement of OR workers, and the dissolution of its interdisciplinarity. Then the changes in OR's environment which should have evoked adaptive responses from it, but didn't, are considered. The increasing inappropriateness of OR's methodology is discussed by focusing on the deficiencies of its concept and practice of optimization, and its pursuit of objectivity. These deficiencies, it is argued, can only be overcome by a comprehensive reconceptualization of the field, its methodology, the way it is practised, and the way students are educated to practise it.     

Soft OR in China: A critical report

As China’s reform steps into the ‘deep water zone’ where value complexity becomes paramount, general-purpose decision-making aids such as Operational Research (OR) are increasingly confronted with the challenge of dealing with interest conflicts. However, due to historical events and institutional circumstances, OR in China to date is largely constrained by a technocratic approach which is not fit for purpose. Encouragingly, recent OR innovations inside China signify a conscious move to embrace value plurality and tackle social conflicts. OR is not merely a neutral tool for solving technical problems, but a world-building discourse that shapes society. The future of OR, particularly Soft OR, in China will be determined by whether OR workers are willing and capable to act as institutional entrepreneurs promoting scientific and democratic decision-making that deepens the reform toward an open, just and prosperous society. The implications go beyond the OR community and China’s borders.     

Orientation-reversing actions on lens spaces and Gaussian integers

A finite group action on a lens space L(p,q) has ‘type OR’ if it reverses orientation and has an invariant Heegaard torus whose sides are interchanged by the orientation-reversing elements. In this paper we enumerate the actions of type OR up to equivalence. This leads to a complete classification of geometric finite group actions on amphicheiral lens spaces L(p,q) with p>2. The family of actions of type OR is partially ordered by lifting actions via covering maps. We show that each connected component of this poset may be described in terms of a subset of the lattice of Gaussian integers ordered by divisibility. This results in a correspondence equating equivalence classes of actions of type OR with pairs of Gaussian integers.     

How Important are Models to Operational Research?

This paper starts from the assumption that the use of modelsis central to the methodology of operational research (OR).The concept is clarified by reference to its formal use in mathematicallogic. A justification for the use of models in decision makingis given. This is contrasted with the reasons why traditionalOR models are frequently not used by practising OR workers (letalone managers). An attempt is made to resolve this contrastbetween the practice of OR by academics with those closer tocommercial decision making. The proper relationship betweenthe two activities is suggested.     

The practice of operational research in Taiwan

This paper presents the results of a questionnaire survey of operational research/management science (OR/MS) practices in Taiwanese companies. The survey was addressed to the current status and future perspectives of OR/MS in Taiwan. During the spring of 2001, 2000 questionnaires were mailed to the top 1000 domestic manufacturing firms and top 1000 domestic service organizations. These asked questions concerning specific OR/MS techniques being used, application areas of OR/MS, reasons for using OR/MS, reasons for not using OR/MS, difficulties encountered practically, and future perspectives. Results from 262 valid respondents provided several informative findings. Compared with the 1995 survey of Kao et al, it found that the percentage of companies that have used OR/MS techniques increased from 62.7% in 1995 to 76.7% in 2001. Also, the percentage of companies that have never heard of OR/MS decreased from 16.1% in 1995 to 11.1% in 2001. Because of the Taiwan government recently developing educational and training programs in OR/MS, it found that the importance of OR/MS has been recognized by Taiwan companies as an efficient management tool for economic development, and the usage of OR/MS will continuously increase.     

Knowledge management: a review of the field and of OR's contribution

This paper examines the field of knowledge management (KM) and identifies the role of operational research (OR) in key milestones and in KM's future. With the presence of the OR Society journal Knowledge Management Research and Practice and with the INFORMS journal Organization Science, OR may be assumed to have an explicit and a leading role in KM. Unfortunately, the origins and the evidence of recent research efforts do not fully support this assumption. We argue that while OR has been inside many of the milestones there is no explicit recognition of its role and while OR research on KM has considerably increased in the last 5 years, it still forms a rather modest explicit contribution to KM research. Nevertheless, the depth of OR's experience in decision-making models and decision support systems, soft systems with hard systems and in risk management suggests that OR is uniquely placed to lead future KM developments. We suggest that a limiting aspect of whether OR will be seen to have a significant profile will be the extent to which developments are recognized as being informed by OR.     

Further Areas for O.R. Modelling in Industry

This paper sets out the case for OR workers embarking on the construction of models of wider scope than has been traditional. Changing industrial conditions emphasize the need to include the social costs of absenteeism, high labour turnover, training and indifferent quality in the evaluation of new projects, as well as the influence on productivity of these factors, and, more especially, of the means devised to overcome them. New criteria of effectiveness are required.A plea is made for OR to be involved in model building of the new patterns of industrial organization; such models could help the uncommitted countries to explore the alternatives at factory and union levels. A comprehensive model would therefore need also to quantify the effect of alternative union structures and strategies on industrial output and on the living standards of the workers.Quantification presents formidable difficulties but to avoid such problems would condemn OR to a role of perpetual sub-optimization.     

The development of management sciences/operational research discourses: surveying the trends in the US and the UK

This paper explores the trends in American and British management science/operational research (MS/OR) during the last 25 years. We argue that British MS/OR has developed a soft and systemic approach to MS/OR practice, which has resulted in the emergence of a number of interpretive and critical-oriented methodologies. American MS/OR practice has remained closed to the positivistic discourse. Using a set of keywords and authors’ names associated with the main features of the interpretive and critical MS discourses, we surveyed articles published in three major US MS/OR journals. We compare these results with trends in the UK MS/OR scene. Findings appear to confirm the different directions taken by the MS/OR practice across the Atlantic. The paper posits possible reasons underpinning these differences: firstly, the particular methodological path followed by the British MS/OR, from early ‘soft systems’ applications in the early 1970s to the now well-established ‘Problem Structuring Methods’; and secondly, continuous engagement between the systems and MS/OR British communities (a dialogue that seems not to have occurred in the US). The paper contributes to a reflection on the MS/OR historical developments and contrasts these developments in both countries, two areas of OR significantly under-researched.     

Visual simulation in hospitals: A managerial or a political tool?

In hospitals, managerial change is often a matter of negotiation and discussion between medical, administrative and nursing disciplines. Any OR intervention should therefore: (a) be easily understandable by all concerned; (b) aid discussion of options. Visual interactive simulation meets these requirements. A complex of surgical services comprising several wards and operating theatres has been modelled, in such a way that movements of patients, variation in waiting lists, bed occupancy etc. can all be seen on a visual display screen. A simultaneous study of the managerial environment of the surgical unit has revealed the importance of internal politics, and the role which the simulation model may play in bids for resources. It is suggested that it is normal for OR projects to be used in this way. The implications for design of OR projects are discussed.     

A Man Before His Time— Stephen Lennox Cook, 1919-1979

This paper presents an address given ‘in praise of Steve Cook’ at the 1989 Cambridge Conference on OR and the Social Sciences. The preamble explains why it takes the form it does and offers a few general views on how Steve's work might be re-examined in the light of current interest in furthering a closer rapport between OR and other specializations.     

On the origins of OR and its institutions

Operational Research (OR) is the science of decision-making. From its military origins on the eve of World War II, OR has over the past seven decades matured to become a discipline that is recognised worldwide for its contributions to managerial planning and complex operations on all levels within both private companies and public institutions. Besides being an indispensable tool as a means for decision support, OR is today a well-established academic discipline and a field with its own institutions. Thus, OR-professionals are joined in national societies worldwide, assembled since 1959 in the global organization International Federation of OR Societies (IFORS) which again is subdivided into four Regional Groupings. Among those is the Association of European OR Societies (EURO) having as members the national societies of 31 countries notably in Europe. Two questions will be addressed: what is OR all about? How do National OR societies fit within the frameworks of IFORS and EURO? Partial answers are provided to both.     

Independent learning and operational research in the classroom

While Operational Research and Education are common keywords in OR journals, most work focuses on course content. Relatively little has been written about processes of education and learning in OR. This paper adds to this important area by considering the use of more Independent Learning (IL) in Operational Research education. Included is an explanation of IL and justification for using it. Activities which encourage IL are described and supported by three case studies which give examples of how an academic might introduce IL into a range of OR education settings. Other topics include IL and assessment, arguments against the use of IL, and critical success factors.     

A Planning Problem Combining Calculus of Variations and Optimal Transport

We consider some variants of the classical optimal transport where not only one optimizes over couplings between some variables x and y but also over some control variables governing the evolutions of these variables with time. Such a situation is motivated by an assignment problem of tasks with workers whose characteristics can evolve with time (and be controlled). We distinguish between the coupled and decoupled case. The coupled case is a standard optimal transport with the value of some optimal control problem as cost. The decoupled case is more involved since it is nonlinear in the transport plan.     

Constructing Ramsey graphs from Boolean function representations

Explicit construction of Ramsey graphs or graphs with no large clique or independent set, has remained a challenging open problem for a long time. While Erdös’ probabilistic argument shows the existence of graphs on 2n vertices with no clique or independent set of size 2 ⁿ , the best explicit constructions achieve a far weaker bound. There is a connection between Ramsey graph constructions and polynomial representations of Boolean functions due to Grolmusz; a low degree representation for the OR function can be used to explicitly construct Ramsey graphs [17,18]. We generalize the above relation by proposing a new framework. We propose a new definition of OR representations: a pair of polynomials represent the OR function if the union of their zero sets contains all points in {0, 1} ⁿ except the origin. We give a simple construction of a Ramsey graph using such polynomials. Furthermore, we show that all the known algebraic constructions, ones to due to Frankl-Wilson [12], Grolmusz [18] and Alon [2] are captured by this framework; they can all be derived from various OR representations of degree O(√n) based on symmetric polynomials. Thus the barrier to better Ramsey constructions through such algebraic methods appears to be the construction of lower degree representations. Using new algebraic techniques, we show that better bounds cannot be obtained using symmetric polynomials.     

Design Science,the design of systems and Operational Research: back to the future?

The relationship between the science of decision making and the design of systems that support or automate the decision-making process is vital to both academic and practical Operational Research (OR). There is a long-standing need to better understand how OR can be structured so as to contribute to the design of systems, rather than just the science of decisions. This paper articulates the notion of design-oriented OR, particularly within the context of IT-enabled systems, as one approach to addressing this issue. It proposes Design Science (DS) as one way of achieving design-oriented OR, and suggests a reference model for DS as a design-oriented approach to OR. The use and value of DS within the broader remit of management research, and differences with existing systems methodologies, are briefly considered. It concludes by noting that a DS approach would return OR, at least partially, to the values and approach of early OR practitioners, and hence back to the future.