Profiles of the European Working Groups

In addition to the EURO conferences and the European Journal of Operational Research, the third major justification so far for the very existence of EURO as an association is the European Working Groups (EWGs).Based upon the booklet, “Report on the EURO Working Groups”, produced in 1981 by EURO in cooperation with European Institute for Advanced Studies in Management, the present paper comprises profiles of 10 EWGs. To stimulate interest in the existing groups and possible also in the establishment of new groups, the “Charter of the European Working Groups” is provided in extenso in the concluding section.     

Operations research methods in political decisions: a case study on the European Parliament composition

In this paper, we show that operations research methods can be successfully applied to support decision-making in politics on the case study of the apportionment of seats in the European Parliament. The related political constraints and assumptions are quantitatively described and the optimization problem is formulated. On this basis, it is revealed that the current composition of the European Parliament as well as some intuitive propositions do not respect degressive proportionality as far as it was assumed. Nevertheless, our algorithm allows us to find better solutions, and among them, there is only one best allocation, which respects degressive proportionality as far as possible, according to the well known and often applied measures. Namely, over 9 thousands allocations consistent with the political requirement “nobody gains and nobody loses more than one” are referred to over 5.4 millions degressively proportional solutions, and only one allocation is revealed to be the best for all defined criteria under given populations of countries.     

On the asymptotic equilibrium of a population system with migration

In the analysis of economic and social issues of a country (or any larger or smaller socio-economic unit) the demographic dynamics of the considered population often play a crucial role. Very current emergencies in this respect are e.g. ageing, longevity risk, state-run healthcare etc. Over the last decade migration between EU countries also became an important issue, and in recent years the uncontrolled migration from non-EU countries is also a major concern. Therefore, the better theoretical understanding of the evolutionary mechanism of age-classified populations interacting via migration, is a timely modelling-methodological task. This paper is a preliminary demographic methodological contribution to a further research in support of socio-economic modelling and decision making concerning migration issues.It is known that in the framework of the classical age-specific Leslie model, under simple demographic conditions, a closed population in the long term tends to an equilibrium age distribution. As the main theoretical result of the paper, a similar convergence is proved for a system of several populations with migration between them, and this long-term behaviour (convergence theorem) is extended to systems of sex-structured populations. Based on the latter model, medium term projections are also analysed concerning the effect of migration among countries on the development of the old-age dependency ratio (the proportion of pensioner age classes to active ones), which is an aggregate scalar indicator of ageing, a major concern in most industrialized countries. Illustrative simulation analysis is carried out with data from three European countries.     

Implementation of IBL in Europe from an Australasian perspective

In this paper the situation in Australasia with respect to research, curricula and practice in inquiry-based learning in mathematics education is examined. As an organising frame the work of researchers in the Mathematics Education Research Group of Australasia (MERGA) was examined for points of intersection with several of the papers that have arisen from the international PRIMAS project, one of several projects funded by the European Union which follow the recommendations of the Rocard Report (Rocard et al. 2007). Although MERGA services researchers in countries such as Singapore in addition to Australia and New Zealand, a survey of outputs of members showed that the latter two countries had more of a tradition of inquiry-based learning practices and research in mathematics education than did Asian countries under the MERGA umbrella such as Singapore. For this reason the focus here is on mathematics education in the schools in these two countries and the classroom research in them that extends or complements the research or issues raised in other papers in this issue of ZDM.     

董事会控制与盈余质量——中国证券市场的实证分析

基于我国沪深两市上市公司2002年至2005年的数据,对我国上市公司从董事会结构和董事会成员工作情况角度,对董事会在上市公司盈余质量上的控制作用进行了实证分析.实证发现:董事会规模较大、董事会中设立审计委员会对公司盈余质量的正面作用越大,且相对于基本盈余回报模型,有增量信息解释能力.董事会规模在13人时,董事会对盈余质量的正面效应最大.董事会成员工作情况(董事会开会的次数、独立董事的工作地点与公司所在地一致性、成立一年以上的审计委员会)对盈余质量的提高有一定的成效,且相对于基本盈余回报模型,有一定的增量信息解释能力.但实证不支持独立董事对盈余质量提高的正面作用.     

Compactness for manifolds and integral currents with bounded diameter and volume

By Gromov??s compactness theorem for metric spaces, every uniformly compact sequence of metric spaces admits an isometric embedding into a common compact metric space in which a subsequence converges with respect to the Hausdorff distance. Working in the class of oriented k-dimensional Riemannian manifolds (with boundary) and, more generally, integral currents in metric spaces in the sense of Ambrosio?CKirchheim and replacing the Hausdorff distance with the filling volume or flat distance, we prove an analogous compactness theorem in which however we only assume uniform bounds on volume and diameter.     

OR in healthcare: A European perspective

The European Working Group “Operational Research Applied to Health Services” (ORAHS) is one of the domain specific EURO Working Groups organized by EURO - the European Association of Operational Research Societies. In this paper we report on the development of ORAHS as a platform for OR in health, and analyse the papers presented at meetings over the 35 years of its existence. We propose a two-way framework for analysis, where one dimension is the nine stages of the product life cycle: identifying consumer requirements, designing a new service to meet these requirements, forecasting demand for such a service, securing resources for it, allocating these resources, developing Programs & Plans to use these resources for delivering the service, establishing criteria for service delivery, managing the performance of the service, and finally, evaluating its performance. The other dimension is a three-level classification into broad application areas referring to processes at different levels in healthcare: Patients & Providers, Units & Hospitals, and Regional & National. We use this framework to carry out a quantitative analysis of all the papers presented during the meetings of ORAHS since its inception in 1975. We then describe developments over this period in applying OR approaches and techniques to healthcare, and present an overview of the main application areas and challenges.     

A look at the past and present of optimization – An editorial

This special issue of the European Journal of Operational Research is devoted to the EURO XXIV Conference, that was held at the facilities of the University of Lisbon (Portugal) from July 11 to July 14, 2010. With over 700 sessions for a total of approximately 2350 presentations, and with 2700 participants (delegates and accompanying persons) coming from 69 countries, this was the largest EURO conference ever.     

Are economically advanced countries more efficient in basic and applied research?

Research and development (R&D) of countries play a major role in a long-term development of the economy. We measure the R&D efficiency of all 28 member countries of the European Union in the years 2008–2014. Super-efficient data envelopment analysis (DEA) based on robustness of classification into efficient and inefficient units is adopted. We use the number of citations as output of basic research, the number of patents as output of applied research and R&D expenditures with manpower as inputs. To meet DEA assumptions and to capture R&D characteristics, we analyze a homogeneous sample of countries, adjust prices using purchasing power parity and consider time lag between inputs and outputs. We find that the efficiency of general R&D is higher for countries with higher GDP per capita. This relation also holds for specialized efficiencies of basic and applied research. However, it is much stronger for applied research suggesting its outputs are more easily distinguished and captured. Our findings are important in the evaluation of research and policy making.     

An entropy-based measurement of working time flexibility

Working time flexibility is of major concern to companies, and must be established by reaching arrangements with workers. Comparing flexibility arrangements is far from easy. Measures of flexibility that assume a probability distribution of future demand are not really measuring flexibility, but rather risk. We define a space of states made up of possible working hours over several periods, and apply three measures of flexibility to it: the proportion of feasible states, the average cost and a new entropy-based measure of flexibility (EMF). The EMF is based on Shannon’s entropy. We propose the use of three measures simultaneously for comparing the flexibility provided by a working time arrangement. Two examples are given: one that assesses the flexibility generated by using time accounts and overtime in a working time accounts (WTAs) modality, and one that compares the WTAs and hiring and firing (H&F) modalities.     

Localization with respect to a class of maps I — Equivariant localization of diagrams of spaces

Homotopical localizations with respect to a set of maps are known to exist in cofibrantly generated model categories (satisfying additional assumptions) [4, 13, 24, 35]. In this paper we expand the existing framework, so that it will apply to not necessarily cofibrantly generated model categories and, more important, will allow for a localization with respect to a class of maps (satisfying some restrictive conditions). We illustrate our technique by applying it to the equivariant model category of diagrams of spaces [12]. This model category is not cofibrantly generated [8]. We give conditions on a class of maps which ensure the existence of the localization functor; these conditions are satisfied by any set of maps and by the classes of maps which induce ordinary localizations on the generalized fixed-points sets. During the preparation of this paper the author was a fellow of Marie Curie Training Site hosted by Centre de Recerca Matemàtica (Barcelona), grant no. HPMT-CT-2000-00075 of the European Commission.     

Conditions for proving by mathematical induction to be explanatory

In this paper we consider proving to be the activity in search for a proof, whereby proof is the final product of this activity that meets certain criteria. Although there has been considerable research attention on the functions of proof (e.g., explanation), there has been less explicit attention in the literature on those same functions arising in the proving process. Our aim is to identify conditions for proving by mathematical induction to be explanatory for the prover. To identify such conditions, we analyze videos of undergraduate mathematics students working on specially designed problems. Specifically, we examine the role played by: the problem formulation, students’ experience with the utility of examples in proving, and students’ ability to recognize and apply mathematical induction as an appropriate method in their explorations. We conclude that particular combinations of these aspects make it more likely that proving by induction will be explanatory for the prover.     

A Magneto-Thermo-Elastic Identification Problem with a Moving Boundary in a Micro-Device

In this paper we model a thermally actuated device in the microdomain: a hollow metallic cylinder, coaxially located with respect to a current-carrying cable inside the cylinder is considered. Owing to induction heating, we have to deal with a (nonlinear) magneto-thermo-elastic problem with a moving boundary that we consider in the quasi static case. Assuming that the intensity of the current is unknown, we have to solve an identification problem consisting of identifying the waveform of the electric current, when an additional information on the magnitude of the magnetic field is supplied on the inner face of the cylinder. After setting our direct problem in the general form, we change it to a simpler, but handful, formulation. Working in the class of classical Hölder spaces, we can prove the existence and uniqueness of the solution to our identification problem.     

Calculus in European classrooms: curriculum and teaching in different educational and cultural contexts

In this paper we provide a first overview of the landscape with respect to calculus teaching in European classrooms, an area where research is very limited. In particular through a small expert-based survey and a literature review, we trace the development of calculus teaching at schools in a number of European countries and identify commonalities and differences. In the current curriculum developments, we notice a reduction in the content of calculus and a more informal approach. The use of digital tools has started to be integrated in calculus teaching in most countries. However in some nations, teaching of calculus in the classroom is rather traditional, focusing on procedural aspects of knowledge. Moreover, in cases where more informal and conceptual teaching approaches are used in the classroom, often contradictions seem to exist with other contextual matters such as examination requirements. Finally, we discuss the future of calculus teaching in Europe.     

A Distributional Approach to Multiple Stochastic Integrals and Transformations of the Poisson Measure, II

We study a class of “nonpoissonian” transformations of the configuration space (over a space of the form G=S×?, where S is a complete separable metric space) and the corresponding transformations of the Poisson measure. For the Poisson measures of the Lévy-Khinchin type we find conditions which are sufficient to ensure that the transformed measure (which in general is nonpoissonian) is absolutely continuous with respect to the initial Poisson measure and derive an expression for the corresponding Radon-Nikodym derivative. To this end we use a distributional approach to Poisson multiple stochastic integrals. This is the second of a series of papers, as compared to the first part the space G is different and the intensity measure is more general, allowing a stronger singularity at the origin.     

Conjugate-normal matrices: A survey

Conjugate-normal matrices play the same important role in the theory of unitary congruence as the conventional normal matrices do with respect to unitary similarities. However, unlike the latter, the properties of conjugate-normal matrices are not widely known. Motivated by this fact, we give a survey of the properties of these matrices. In particular, a list of more than forty conditions is given, each of which is equivalent to A being conjugate-normal.     

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.     

Jumping nonlinearities and weighted Sobolev spaces

Working in a weighted Sobolev space, a new result involving jumping nonlinearities for a semilinear elliptic boundary value problem in a bounded domain in R^N is established. The nonlinear part of the equation is assumed to grow at most linearly and to be at resonance with the first eigenvalue of the linear part on the right. On the left, the nonlinearity crosses over (or jumps over) several higher eigenvalues. Existence is obtained through the use of infinite-dimensional critical point theory in the context of weighted Sobolev spaces and appears to be new even for the standard Dirichlet problem for the Laplacian.     

国家治理体系完善能抑制企业盈余管理吗？——基于准自然实验的经验证据

本文以沪深A股上市公司为研究对象,从巡视监督的视角考察了国家治理体系完善的公司治理效应。研究结论表明:巡视监督能够有效的抑制企业盈余管理,降低24%的应计盈余管理和22%的真实盈余管理。采用平行趋势检验、安慰剂检验和倾向得分法之后的结论依然稳健;相对于地方巡视监督而言,中央巡视监督对企业盈余管理治理的效果更为显著;巡视监督对于腐败地区企业盈余管理治理效应更强。本文丰富了国家治理体系发挥公司治理效应的文献体系,揭示了制度建设在实体经济发展中的重要作用。     

Theory usage and theoretical trends in Europe: a survey and preliminary analysis of CERME4 research reports

The 29th PME research forum on theories included only one European perspective on mathematics education. In order to convey trends in theory usage in Europe we compile, survey and analyze a large subset of the research papers from the 4^th European Congress on Mathematics Education (CERME4). That is, this paper includes a discussion of trends seen within CERME4 reports¹ on theory usage by European researchers inseven of the fourteen working groups and (a) Outlines similarities and differences in theory usage and (b) takes a futuristic stance on ways in which researchers from different traditions could understand each other. Such an enterprise would further Hans-Georg Steiner's vision of bridging theoretical traditions which are independently formulated in different regions of the world.