Keynote Lectures

Optimization in Sports League Scheduling
Dries Goossens, Ghent University, Belgium, Belgium

Operations Research and Voting Theory
Olivier Hudry, Independent Researcher, France, France

The Role of Operations Research to Support Portuguese SMEs: Challenges and Opportunities
José Oliveira, Universidade do Minho, Portugal, Portugal

Abstract
Millions of people, all over the world, are enthralled by sports, be it actively participating or as a fan or spectator. At the same time, almost every sports competition needs a schedule of play, stating who will play whom, when, and where. Not much more than a decade ago, most professional sports competitions were scheduled by unskilled personnel, equipped with little more than pen and paper. A good schedule is important though, because it has an effect on the fairness and outcome of the competition, public attendance, commercial interests, as well as security and the cost of policing. As league owners managed to close astonishing broadcasting deals and the financial interests in the sports industry continued to grow, the importance of a good schedule became more and more apparent.

Sports scheduling is a young academic discipline: although the first substantial contributions were published in the early 80’s (e.g. De Werra, 1981), a considerable increase in sports scheduling articles appeared only in recent years, including publications in top journals in operations research. Simultaneously, several academics reached out to the sport scheduling practitioners, offering new methods to deal with the increasingly more complex problem of scheduling a league. In this talk, we attempt to illustrate the many ways in which the sports industry can benefit from operations research, particularly in sports scheduling.

We discuss practical applications involving the scheduling of the Belgian Pro League football (soccer), for which we develop the official schedule since 2006. Our contract with the Belgian Pro League now involves 2 professional and 1 amateur division with interdependencies (e.g. teams from different divisions sharing a stadium or a police force) and play-offs. We present methods that have proven their value in real-life sport scheduling. We discuss fairness issues, such as the carry-over effect, as well as a discrete choice experiment we carried out in order to estimate the impact of the schedule on TV viewership and stadium attendance.

Abstract
One main concern of voting theory is to determine a procedure for choosing a winner from among a set of candidates, based on the preferences of the voters or, more ambitiously, for ranking all the candidates or a part of them. Such a situation occurs, obviously, in the field of social choice and welfare and especially of elections, but also in many other fields: games, sports, artificial intelligence, spam detection, Internet applications, statistics, and so on. It is customarily agreed that the search for a “good” voting procedure goes back at least to the end of the eighteenth century, with the works of the chevalier Jean-Charles de Borda (1733-1799) and of Marie Jean Antoine Nicolas Caritat, marquis de Condorcet (1743-1794). Kenneth Arrow’s theorem (1951) ruined the hope of designing a “good” procedure by showing that there does not exist a “good” voting method, with respect to some “reasonable” axiomatic properties; this is known as the famous “Arrow’s impossibility theorem”.
In this presentation, we will pay attention to some contributions of operations research to the design and the study of some voting procedure.
First, we show through an easy example that the voting procedure plays an important role in the determination of the winner. More precisely, we show how, for an election with 5 candidates, the choice of the voting procedure allows electing anyone of the 5 candidates with the same individual preferences of the voters. This example provides also the opportunity to recall some main procedures, including the ones advocated by Borda or by Condorcet, and leads to the statement of Arrow’s theorem.
In a second step, more devoted to a mathematical approach, we define the so-called median procedure, extending Condorcet’s method. In this procedure, the aim is to compute a ranking of the candidates which minimizes the number of disagreements with respect to the voters’ preferences. Thus we obtain a combinatorial optimization problem. We show how to state it as a linear programming problem with binary variables or as a graph theoretic problem. This allows also studying the complexity of this median procedure.
Last, we show, once again through easy examples, that the lack of some desirable properties for the considered voting procedure may lead some “paradoxes” like the following ones:
- Abstention can lead to a more desirable result for me than if I vote for my favourite candidate!
- If I vote for my favourite candidate, he or she loses the election but if I vote for the candidate that I most dislike, my favourite candidate wins!
- Even if every voter prefers candidate A to candidate B (unanimity), B may beat A in the election!
- and so on...

Abstract
Since Portugal joined the European Economic Community in 1986, significant structural changes have occurred in the Portuguese economy in response to the growing challenges and opportunities that are result of globalisation and European integration. Portuguese companies, especially small and medium-sized enterprises (SMEs), had to adjust their business and their production processes to meet the requirements of their new European customers. Traditionally SMEs in northern Portugal belonged to activity sectors with intensive but low-skilled and low-productivity labour with an emphasis on footwear, textiles and clothing. For some time, companies remained in a competitive position through a strategy of low wages.

Twenty years later (2005), the opening up of the European market promoted strong competition and overcapacities due to new market entrants from south-east Asia and the eastern European countries. Consequently, many Portuguese SME companies have ended their manufacturing operations in Europe; other companies have chosen to move to countries where the cost of labour is lower. Several companies that survived the opening of the European market selected the production of higher added value products based on innovation and the incorporation of technology.  Other companies have chosen to outsource the production of their products to companies located in very low-wage countries, so that their products remain competitive. All these strategies have resulted in more complex manufacturing processes.

Over the past 30 years, Portuguese SMEs achieved important improvements (innovations) in their businesses, in their productivity by incorporating information and communications technologies, using quality management system for the institution of a continuous improvement process, and other practices that allowed them to control and minimize the cost of production and/or improve the level of service provided. In the last decade there has been a very interesting evolution of lean management projects in Portuguese SMEs that seek for excellence in security, quality, cost and delivery, improving their processes, eliminating loss and reducing variability.

We are currently surfing the “technological wave” in direction to the “Industry 4.0”, and Portuguese SME companies will face new challenges. Lean practices are no longer enough to ensure that SMEs can increase their level of competitiveness, since the manufacturing process no longer has visible (or easy to identify) waste. There is now an awareness among managers of SMEs that it is necessary to include other optimization measures in their (production) processes. The change in the production paradigm in mass to the mass customization, leading to the emergence of increasingly smaller orders, involves the manufacture of small series with delivery dates ever shorter, and supply with increasingly competitive prices. Satisfying these demands requires increasingly detailed studies of the real problems, and the development of solution methods increasingly sophisticated.

It is in this context that Operational Research will be increasingly used as a methodology to promote the increase of competitiveness of enterprises. However, in the case of the Portuguese SMEs the resources for scientific research investment in partnerships with universities are very limited, or even non-existent. In order to change this situation incentive programs have been provided for modernization and innovation of SMEs and their production processes. The establishment partnerships enterprise-university is still embryonic, and it is for the universities (in this case of Operational Research) demonstrate that they can produce better solutions than those that companies succeed by their own means. This lecture will present some case studies of operational research methodology implementation in the context of SMEs in the north of Portugal.