Researchers and teachers working together to deal with the issues, opportunities and challenges of implementing CAS into the senior secondary mathematics classroom

Introducing CAS calculators into the mathematics classroom has the potential to confront classroom practice more than the introduction of graphics calculators. CAS calculators are capable of performing many of the routine procedures that are taught in the secondary school curriculum and having CAS calculators available in the classroom has implications for pedagogy, interactions in the classroom and practice of routine procedures. This paper will describe the way that the researchers and a group of teachers in three schools worked together to deal with issues and opportunities associated with the implementation of CAS calculators into the year 11 and 12 curriculum during 2001 and 2002 in Victoria, Australia.     

Role of Interaction in Enhancing the Epistemic Utility of 3D Mathematical Visualizations

Many epistemic activities, such as spatial reasoning, sense-making, problem solving, and learning, are information-based. In the context of epistemic activities involving mathematical information, learners often use interactive 3D mathematical visualizations (MVs). However, performing such activities is not always easy. Although it is generally accepted that making these visualizations interactive can improve their utility, it is still not clear what role interaction plays in such activities. Interacting with MVs can be viewed as performing low-level epistemic actions on them. In this paper, an epistemic action signifies an external action that modifies a given MV in a way that renders learners’ mental processing of the visualization easier, faster, and more reliable. Several, combined epistemic actions then, when performed together, support broader, higher-level epistemic activities. The purpose of this paper is to examine the role that interaction plays in supporting learners to perform epistemic activities, specifically spatial reasoning involving 3D MVs. In particular, this research investigates how the provision of multiple interactions affects the utility of 3D MVs and what the usage patterns of these interactions are. To this end, an empirical study requiring learners to perform spatial reasoning tasks with 3D lattice structures was conducted. The study compared one experimental group with two control groups. The experimental group worked with a visualization tool which provided participants with multiple ways of interacting with the 3D lattices. One control group worked with a second version of the visualization tool which only provided one interaction. Another control group worked with 3D physical models of the visualized lattices. The results of the study indicate that providing learners with multiple interactions can significantly affect and improve performance of spatial reasoning with 3D MVs. Among other findings and conclusions, this research suggests that one of the central roles of interaction is allowing learners to perform low-level epistemic actions on MVs in order to carry out higher-level cognitive and epistemic activities. The results of this study have implications for how other 3D mathematical visualization tools should be designed.     

Mathematical programming time-based decomposition algorithm for discrete event simulation

Mathematical programming has been proposed in the literature as an alternative technique to simulating a special class of Discrete Event Systems. There are several benefits to using mathematical programs for simulation, such as the possibility of performing sensitivity analysis and the ease of better integrating the simulation and optimisation. However, applications are limited by the usually long computational times. This paper proposes a time-based decomposition algorithm that splits the mathematical programming model into a number of submodels that can be solved sequentially to make the mathematical programming approach viable for long running simulations. The number of required submodels is the solution of an optimisation problem that minimises the expected time for solving all of the submodels. In this way, the solution time becomes a linear function of the number of simulated entities.     

Computationally modeling organizational learning and adaptability as resource allocation: An artificial adaptive systems approach

A framework for and a computational model of organizational behavior based on an artificial adaptive system (AAS) is presented. An AAS, a modeling approach based on genetic algorithms, enables the modeling of organizational learning and adaptability. This learning can be represented as decisions to allocate resources to the higher performing organizational agents (i.e., individuals, groups, departments, or processes, depending on the level of analysis) critical to the organization's survival in different environments. Adaptability results from the learning function enabling the organizations to change as the environment changes. An AAS models organizational behavior from a micro-unit perspective, where organizational behavior is a function of the aggregate actions and interactions of each of the individual agents of which the organization is composed. An AAS enables organizational decision making in a dynamic environment to be modeled as a satisficing process and not as a maximization process. To demonstrate the feasibility and usefulness of such an approach, a financial trading adaptive system (FTAS) organization is computationally modeled based on the AAS framework. An FTAS is an example of how the learning mechanism in an AAS can be used to allocate resources to critical individuals, processes, functions, or departments within an organization.     

Analysing quality with generalized kinetic methods

A mathematical structure is developed with the aim of analysing the time evolution of the quality of a composite system such as a medical service inside an hospital. The approach belongs to the so-called Generalized Kinetic Theory, and consists of a set of balanced statistical equations on the probability distribution functions of the system populations over a state variable that represents the perceived quality. Internal and external actions are taken into account by means of direct interactions and ensemble terms. The mathematical framework is developed for a general setting. As a particular case, a model is suggested with reference to the quality of a specific medical service.     

Modeling the role of government efforts in controlling extremism in a society

People having extreme idealogies affect the process in a region using fear of terror acts, money power, and the word of mouth communication network to change individuals to their way of thinking. This forces government to divert its limited financial resources for controlling extremism and thus affecting development. In this paper, therefore, a nonlinear mathematical model is proposed to study the dynamics of extremism governed by four dependent variables, namely, number of people in the general population having no extreme ideology, number of extreme ideologists, number of isolated ideologists (prisoners), and the cumulative density of government efforts and their interactions. The model is analyzed using the stability theory of differential equations and computer simulation. The analysis shows that if appropriate level of government efforts is applied on extremists, the spread of their ideology can be controlled in the general population. A numerical study of the model is also carried out to investigate the effects of certain parameters on the spread of extremism confirming the analytical results.Copyright © 2014 John Wiley & Sons, Ltd.     

A multiple criteria sorting method where each category is characterized by several reference actions: The Electre Tri-nC method

This paper presents Electre Tri-nC, a new sorting method which takes into account several reference actions for characterizing each category. This new method gives a particular freedom to the decision maker in the co-construction decision aiding process with the analyst to characterize the set of categories, while there is no constraint for introducing only one reference action as typical of each category like in Electre Tri-C (Almeida-Dias et al., 2010). As in such a sorting method, this new sorting method is composed of two joint rules. Electre Tri-nC also fulfills a certain number of natural requirements. Additional results on the behavior of the new method are also provided in this paper, namely the ones with respect to the addition or removal of the reference actions used for characterizing a certain category. A numerical example illustrates the manner in which Electre Tri-nC can be used by a decision maker. A comparison with some related sorting procedures is presented and it allows to conclude that the new method is appropriate to deal with sorting problems.     

Microfoundations for diffusion price processes

We study microeconomic foundations of diffusion processes as models of stock price dynamics. To this end, we develop a microscopic model of a stock market with finitely many heterogeneous economic agents, who trade in continuous time, giving rise to an endogeneous pure-jump process describing the evolution of stock prices over time. When the number of agents in the market is large, we show that the price process can be approximated by a diffusion, with price-dependent drift and volatility coefficients that are determined by small excess demands and trading volume in the microscopic model. We extend the microscopic model further by allowing for non-market interactions between agents, to model herd behavior in the market. In this case, price dynamics can be approximated by a process with stochastic volatility. Finally, we demonstrate how heavy-tailed stock returns emerge when agents have a strong tendency towards herd behavior.     

Students’ Conceptions of Congruency Through the Use of Dynamic Geometry Software

This paper describes students’ interactions with dynamic diagrams in the context of an American geometry class. Students used the dragging tool and the measuring tool in Cabri Geometry to make mathematical conjectures. The analysis, using the cK￠ model of conceptions, suggests that incorporating technology in mathematics classrooms enabled a measure-preserving conception of congruency with which students’ could shift focus from shapes to properties. Students also interacted with dynamic diagrams in a novel way, which we call the functional mode of interaction with diagrams, relating outputs and inputs that result when dragging a figure. Students’ participation in classroom interactions through discourse and through actions on diagrams provided evidence of learning using tools within dynamic geometry software.     

Teaching spline approximation techniques using maple

Using Computer Algebra Systems (CAS)-such as MAPLE-in teaching and learning mathematical concepts is a great challenge both from a didactical and a scientific point of view. We have to rewrite our traditional paper based teaching materials for interactive and living electronic worksheets, Only few statements and principles have to be acquired by the learner and the teacher from the CAS and after they can visualise, make animations modify quickly the program data, perform symbolic and numeric calculations step by step and in the whole, and verify deductions on their own. The author prepared Maple worksheets for teaching different types of function approximating techniques, such as interpolation-, least square-, spline and uniform approximation methods for post-graduate mechanical engineering students. In this paper we want to demonstrate how can we keep and improve the famous problem solving principles and rules given by G. Pólya and R. Descartes (Pólya 1962), when we use the capabilities of CAS. The education principles active learning, motivations and the successive phases are getting new meaning in the CAS. Our examples are always concerning with spline functions. Handling the formulas, calculating values and giving proofs are always in the form of Maple statements.     

Developing mathematical modelling skills: The role of CAS

Mathematical modelling as one component of problem solving is an important part of the mathematics curriculum and problem solving skills are often the most quoted generic skills that should be developed as an outcome of a programme of mathematics in school, college and university. Often there is a tension between mathematics seen at all levels as ‘a body of knowledge’ to be delivered at all costs and mathematics seen as a set of critical thinking and questioning skills. In this era of powerful software on hand-held and computer technologies there is an opportunity to review the procedures and rules that form the ‘body of knowledge’ that have been the central focus of the mathematics curriculum for over one hundred years. With technology we can spend less time on the traditional skills and create time for problem solving skills. We propose that mathematics software in general and CAS in particular provides opportunities for students to focus on the formulation and interpretation phases of the mathematical modelling process. Exploring the effect of parameters in a mathematical model is an important skill in mathematics and students often have difficulties in identifying the different role of variables and parameters This is an important part of validating a mathematical model formulated to describe, a real world situation. We illustrate how learning these skills can be enhanced by presenting and analysing the solution of two optimisation problems.     

CAS in general mathematics education

A rational discussion of the use of Computer algebra systems (CAS) in mathematics teaching in general education needs an explicit image of (general) mathematics education, an explication of global perspectives and goals on mathematics teaching focusing on general education (chapter 1). The conception of general education according to the «ability of communication with experts» described in chapter 2 can be such an orientation for analysing, considering, classifying and assessing the didactical possibilities of using CAS. CAS are materialised mathematics allowing for more or less exhaustive outsourcing of operative (also symbolically) knowledge and skills to the machine. This frees up space of time as well as mental space for the development of those competences being in our view relevant for general mathematics education. In chapter 3 the idea of outsourcing and the role of CAS for it is discussed more detailed as well as consequences being possible for the CAS-supported teaching of mathematics. Beyond, CAS can be didactically used and reflected as a model of communication between (mathematical) experts and lay-persons (chapter 4). Chapter 5 outlines some research perspectives.     

Routing of platforms in a maritime surface surveillance operation

Maritime surface surveillance is the process of obtaining and maintaining information about surface ships in a certain sea area. It is carried out by maritime platforms such as frigates, helicopters or maritime patrol aircraft. Surface surveillance plays a vital role in maritime operations like trade embargo operations, counterdrug operations and traditional warfare operations.The problem of finding optimal tactics for a single surveillance unit is a routing problem which can to some extent be considered as an extension of the on-line travelling salesman problem, but there are essential complications which call for a different approach. A mathematical formulation of the surveillance routing problem is given in this paper. The complications of this problem, in comparison to the on-line travelling salesman problem, are explained.This routing problem is part of the rather complicated process of maritime surface surveillance. SURPASS, an acronym of SURface Picture ASSessment, is a computer model which simulates this process. The model SURPASS provides insight into both the means (i.e. platforms and sensors) needed for a surveillance operation and the effectiveness of various existing and newly developed rules for surveillance tactics. The structure of SURPASS is explained, including the way in which it solves the surveillance routing problem. A number of decision rules that can be used in the routing of the surveillance units are described. The effectiveness of these rules is analysed and evaluated.     

A behavioral stock market model

Stock exchanges are modeled as nonlinear closed-loop systems where the plant dynamics is defined by known stock market regulations and the actions of agents are based on their beliefs and behavior. The decision of the agents may contain a random element, thus we get a nonlinear stochastic feedback system. The market is in equilibrium when the actions of the agents reinforce their beliefs on the price dynamics. Assuming that linear predictors are used for prediction of the price process, a stochastic approximation procedure for finding market equilibrium is described. The proposed procedure is analyzed using the theory of Benveniste et al. (Adaptive algorithms and stochastic approximations. Springer, Berlin, 1990). A simulation result is also presented.     

Network manipulation algorithm based on inexact alternating minimization

In this paper, we present a network manipulation algorithm based on an alternating minimization scheme from Nesterov (Soft Comput 1–12, 2020). In our context, the alternative process mimics the natural behavior of agents and organizations operating on a network. By selecting starting distributions, the organizations determine the short-term dynamics of the network. While choosing an organization in accordance with their manipulation goals, agents are prone to errors. This rational inattentive behavior leads to discrete choice probabilities. We extend the analysis of our algorithm to the inexact case, where the corresponding subproblems can only be solved with numerical inaccuracies. The parameters reflecting the imperfect behavior of agents and the credibility of organizations, as well as the condition number of the network transition matrix have a significant impact on the convergence of our algorithm. Namely, they turn out not only to improve the rate of convergence, but also to reduce the accumulated errors. From the mathematical perspective, this is due to the induced strong convexity of an appropriate potential function.

     

Instrumenting Mathematical Activity: Reflections on Key Studies of the Educational Use of Computer Algebra Systems

This paper examines the process through which students learn to make functional use of computer algebra systems (CAS), and the interaction between that process and the wider mathematical development of students. The result of ‘instrumentalising‘ a device to become a mathematical tool and correspondingly ‘instrumenting’ mathematical activity through use of that tool is not only to extend students' mathematical technique but to shape their sense of the mathematical entities involved. These ideas have been developed within a French programme of research – as reported by Artigue in this issue of the journal – which has explored the integration of CAS – typically in the form of symbolic calculators – into the everyday practice of mathematics classrooms. The French research –influenced by socio-psychological theorisation of the development of conceptual systems- seeks to take account of the cultural and cognitive facets of these issues, noting how mathematical norms – or their absence – shape the mental schemes which students form as they appropriate CAS as tools. Instrumenting graphic and symbolic reasoning through using CAS influences the range and form of the tasks and techniques experienced by students, and so the resources available for more explicit codification and theorisation of such reasoning. This illuminates an influential North American study– conducted by Heid – which French researchers have seen as taking a contrasting view of the part played by technical activity in developing conceptual understanding. Reconsidered from this perspective, it appears that while teaching approaches which ‘resequence skills and concepts’ indeed defer – and diminish –attention to routinised skills, the tasks introduced in their place depend on another –albeit less strongly codified – system of techniques, supporting more extensive and active theorisation. The French research high lights important challenges which arise in instrumenting classroom mathematical activity and correspondingly instrumentalising CAS. In particular, it reveals fundamental constraints on human-machine interaction which may limit the capacity of the present generation of CAS to scaffold the mathematical thinking and learning of students. This revised version was published online in July 2006 with corrections to the Cover Date.     

Sharing profits and liabilities of a pool of dockers

The paper is devoted to a practical case taking place in the Rotterdam harbour. A group of stevedoring companies founded a pool of dockers to be able to share human resources. In this way they cover their strongly fluctuating workload. A system to control the pool is developed. On the one hand this system divides the liabilities of the pool among the stevedores and on the other hand it rules the priorities of assignment of human resources. The history leading to the development of this system is discussed, the system itself is sketched and finally some experiences with the system are given. In an appendix some mathematical aspects of the assignment rules are treated.     

FISHERY REGULATION UNDER RATIONAL EXPECTATIONS AND COSTLY DYNAMIC ADJUSTMENT

The regulation of a fishery is examined when firms' decision rules are not invariant to regulatory intervention. When faced with internal dynamic costs, firms have incentives to forecast future regulatory actions. The regulatory “game” becomes one between intelligent agents, not one between an intelligent regulator and “nature”—agents who behave as automatons. Regulations feed back on decisions of agents; this alters the characteristics of the equilibrium time paths of the fish harvest and thus, of the optimal regulatory interventions. Within such a framework equilibrium is characterized and alternative policy interventions are evaluated.     

El Farol revisited: A note on emergence,game theory,and society

The El Farol paper examined the evolution of behavior of visits to a potentially crowded facility, providing an insightful view of how independent agents can coordinate in a “good enough” manner in many situations. This view is extended to considering the interaction between rules and behavior. The context may be such that the importance of the outcome is sufficiently high to merit an extra layer of complexity in the guidance of the emergent behavior and that behavior may signal the need for the additional complexity. © 2011 Wiley Periodicals, Inc. Complexity, 2011