A unified formalism for landmark based representation of maps and navigation plans

We present a unified formalism for representing maps and using them for constructing plans of navigation for an autonomous agent. The foundation of this work lies in addressing key questions that an agent is confronted with when navigating. That is, besides the main task of how to reach the intended destination from the current position, the agent faces other questions like: where am I? what landmarks can I see? where is my destination relative to me and the landmarks I am seeing? Fundamental to this representation is the use of visual landmarks, which are used as pivotal points in the landscape being described. Further, in the representation of spatial information and navigation there are three different viewpoints: first, the localized representation from the viewpoint of a sighted, mobile agent; second, the static representation seen by the map-maker; and third, the view of an external agent giving directions on the basis of his own experience/knowledge. The major contribution of this map model and the associated navigation method lies in the framework which unifies these three different points of view. This unification enables the agent to make no distinction in terms of following implicit instructions contained in a map and the directions given by external agents.

Media-independent information representation and retrieval

In this paper we propose a media-independent knowledge indexing and retrieval system as a basis for an information retrieval system. The representation allows for sharing of low level information bearing objects and at the same time allows for maintaining of user-dependent views. The tools for maintenance and manipulation of concepts focus on the user and user's intentions. The aim of the system is to provide a set of flexible tools and let the user structure the knowledge in his or her own way, instead of attempting to build an all-encompassing common sense, or general knowledge representation.

A point-based representation for intervals

Information about time or space is often expressed in terms of points or intervals, and the relations between points and intervals. The interval based representations fall into two distinct classes based on: (i) closure and (ii) minimal representation of the domain. The advantage of closure based representation is the minimal search time at the expense of time to construct the representation, and the storage requirement. Minimal representation optimises storage required, at the expense of construction and search time. Intervals can be represented in terms of their end points. The information about points can be effectively represented using the closure approach but intervals cannot be represented with their endpoints using a point algebra system.

This paper proposes a point based system of representation for interval relations that does not perform closure. Point information is represented in terms of the known relationships between points. The costs of such a representation lies between the expense of closure and minimisation. The time taken for search and construction is better than for minimisation but not as good as for closure. Respectively, the space used is better than for closure but not as good as for minimisation

Symbolic representation and distributed matching strategies for schematics

This paper describes object-centered symbolic representation and distributed matching strategies of 3D objects in a schematic form which occur in engineering drawings and maps. The object-centered representation has a hierarchical structure and is constructed from symbolic representations of schematics. With this representation, two independent schematics representing the same object can be matched. We also consider matching strategies using distributed algorithms. The object recognition is carried out with two matching methods: (1) matching between an object model and observed data at the lowest level of the hierarchy, and (2) constraints propagation. The first is carried out with symbolic Hopfield-type neural networks and the second is achieved via hierarchical winner-takes-all algorithms

Video indexing by spatial representation

Recent approaches to video indexing and retrieval are either pixel-oriented or object-oriented. While the former approaches focus on motion and changes thereto, the latter focus on spatial relations among objects in the scene. In this paper, a spatial knowledge representation technique combining both approaches is proposed. This representation supplements the spatial knowledge of visual objects with information about their pixel positions in the video frame. It provides a practical way to construct video indices, enabling searching for and retrieval of video sequences that contain motion as well as sparsely disjoint objects

The role of representation in teaching and learning ideas about matter

The research described in this paper is designed around the notion that learning involves the recognition and development of students’ representational resources. This paper describes a classroom sequence in Ideas about Matter that focuses on representations and their negotiation, and reports on the effectiveness of this perspective in guiding teaching, and in providing further insight into student learning. Classroom sequences involving two experienced teachers (2008, Year 8 students) and an inexperienced teacher (2010, Year 7 students) were videotaped using a combined focus on the teacher and groups of students. Video analysis software was used to code the variety of representations used teachers and students, and sequences of representational negotiation. The paper reports on the effect of this approach on teacher pedagogy and on student learning of Ideas about Matter. The paper will present data from video of classroom activities, students’ work samples, student and teacher interviews and pre and post-unit testing, to explore what a representational focus might entail in teaching Ideas about Matter, and the role of representations in learning and reasoning and exploring scientific ideas.

A professional learning program based on a representation intensive pedagogical approach

A representation-intensive pedagogical approach challenges students to generate and negotiate the representations (text, graphs, models, diagrams) that constitute the discursive practices of science, rather than focusing on the text-based, definitional versions of concepts. Previous research conducted on a small scale with a few topics and teachers successfully demonstrated enhanced outcomes for students, in terms of sustained engagement with ideas, and quality learning, and for teachers’ enhanced pedagogical knowledge, and epistemological understanding. This paper explores the efficacy of embedding a representations-intensive pedagogical approach into a state-wide professional learning program that was delivered to Victorian secondary science teachers in 2010/2011. The professional learning program involved participating teachers undertaking two successive days of professional development, then completing a small classroom-based project in their schools before returning for the third day of professional development. The program was supported by online drupal website. In determining the impact of the professional learning program on the teachers’ practice data was collected in the form of program participant surveys, presentations of the teachers’ classroom-based projects, focus group interviews and phone interviews. Teachers demonstrated the applicability of this pedagogical approach by adapting it to a variety of science topics.

Empowering teachers through a professional learning program that focused on a representation intensive pedagogical approach

A representation-intensive pedagogical approach challenges students to generate and negotiate the representations (text, graphs, models, diagrams) that constitute the discursive practices of science, rather than focusing on the text-based, definitional versions of concepts. It thus represents a more active view of knowledge than traditional structural approaches. Previous research conducted on a small scale with a few topics and teachers, successfully demonstrated enhanced outcomes for students, in terms of sustained engagement with ideas, and quality learning, and for teachers enhanced pedagogical knowledge, and epistemological understanding. This paper explores the efficacy of embedding a representations-intensive pedagogical approach into a state-wide professional learning program that was delivered to secondary science teachers in Victoria, Australian, in 2010/2011. The professional learning program involved participating teachers undertaking two successive days of professional development, then completing a small classroom-based project in their schools before returning for the third day of professional development. The program was supported by on online drupal website. In determining the impact of the professional learning program on the teachers’ practice data was collected in the form of program participant surveys, presentations of the teachers’ classroom-based projects, focus group interviews and phone interviews.

A representation-intensive signature pedagogy for school science?

In this paper we examine Shulman’s notion of signature pedagogies for its usefulness extended to school science. We argue that school science is in an important sense an apprenticeship, and that calls for reform in school science are compatible with Shulman’s practice-based vision of professional learning. Two case studies of teaching and learning will be presented based on research in primary and secondary schools that involved working closely with teachers to develop and validate involving a representation-intensive pedagogy that lays claim to bringing school science closer to the knowledge building practices of science. Video images of classrooms, interviews with students and teachers, and documentation of students’ work, were used to construct insights into the teaching and learning process. It is argued that Shulman’s notion of professional practice as involving apprenticeships of knowledge, practice and identity provides a useful lens through which to view this innovation. Shulman’s characterisation of signature pedagogy is used to identify key features of the approach.

Exercising sociomathematical norms in classroom discourse about data representation : insights from one case study of a grade 6 lesson in Indonesia

This paper examines a research study to foster mathematical discourse about data representations among Indonesian students. It was situated in the context of implementing an Indonesian version of Realistic Mathematics Education, labelled as PMRI, in primary schools. A case study of one lesson involving Grade 6 students on the choice of data representations in Yogyakarta will be discussed. The analysis focused on the enacted social norms and sociomathematical norms during a wholeclass discussion and their impacts on students’ knowledge of data representations. The need for constant effort to enact these norms in classroom mathematical discourse is highlighted.