Mind change optimal learning of Bayes net structure

This paper analyzes the problem of learning the structure of a Bayes net (BN) in the theoretical framework of Gold’s learning paradigm. Bayes nets are one of the most prominent formalisms for knowledge representation and probabilistic and causal reasoning. We follow constraint-based approaches to learning Bayes net structure, where learning is based on observed conditional dependencies between variables of interest (e.g., “X is dependent on Y given any assignment to variable Z”). Applying learning criteria in this model leads to the following results. (1) The mind change complexity of identifying a Bayes net graph over variables V from dependency data is |V| 2 , the maximum number of edges. (2) There is a unique fastest mind-change optimal Bayes net learner; convergence speed is evaluated using Gold’s dominance notion of “uniformly faster convergence”. This learner conjectures a graph if it is the unique Bayes net pattern that satisfies the observed dependencies with a minimum number of edges, and outputs “no guess” otherwise. Therefore we are using standard learning criteria to define a natural and novel Bayes net learning algorithm. We investigate the complexity of computing the output of the fastest mind-change optimal learner, and show that this problem is NP-hard (assuming P = RP). To our knowledge this is the first NP-hardness result concerning the existence of a uniquely optimal Bayes net structure.

Mind change efficient learning

This paper studies efficient learning with respect to mind changes. Our starting point is the idea that a learner that is efficient with respect to mind changes minimizes mind changes not only globally in the entire learning problem, but also locally in subproblems after receiving some evidence. Formalizing this idea leads to the notion of uniform mind change optimality. We characterize the structure of language classes that can be identified with at most α mind changes by some learner (not necessarily effective): A language class L is identifiable with α mind changes iff the accumulation order of L is at most α. Accumulation order is a classic concept from point-set topology. To aid the construction of learning algorithms, we show that the characteristic property of uniformly mind change optimal learners is that they output conjectures (languages) with maximal accumulation order. We illustrate the theory by describing mind change optimal learners for various problems such as identifying linear subspaces and one-variable patterns.

Compute inclusion depth of a pattern

We define a concept of inclusion depth (see Definition 1) to capture mind-change complexity [3,1] of pattern identification problems [2]. Our basic question is whether the inclusion depth for any pattern is computable. We conjecture a combinatorial characterization that, if true, leads to a linear time algorithm to compute inclusion depth.

Sharpening the focus of force field analysis

The purpose is to explore the inherent complexity of Kurt Lewin's force field theory through applied analysis of organizational case examples and related methods. The methodology applies a range of tools from the consultancy research domain, including force field analysis of complex organizational scenarios, and applies bricolage and corroboration to emerging discoveries from semi-structured interviews, author experience, critical reflection and literature survey. Findings are that linear representation of internal and external forces in organizational applications of field theory does not fully explain the paradox of inverse vectors in the forces of change. The force field is not an impermeable thing; instead, it morphs. Examples of the inverse principle and its effects are detailed and extended in this analysis. The implications of the research are that force field analysis and related change processes promoted in organizational change literature run the risk of missing key complexities. The inclusion of the inverse principle can provide enhanced, holistic understanding of the prevailing forces for change. The augmentation of the early work of Kurt Lewin, and extension of previous analyses of his legacy in the Journal of Change Management and elsewhere, provide, in this article, change analysis insights that align well with current organizational environments.

School innovation in science : change, culture, complexity

The School Innovation in Science (SIS) initiative has developed and evaluated a model to improve science teaching and learning across a school system. The model involves a framework for describing effective teaching and learning, and a strategy that allows schools flexibility to develop their practice to suit local conditions and to maintain ownership of the change process. SIS has proved successful in improving science teaching and learning in primary and secondary schools. Evidence of variations in the nature and extent of the change is used to argue that the process is essentially cultural in nature, and that change occurs at different levels within a school. Processes supporting change thus need to be flexible and responsive.

The complexity of social practice : understanding inertia and change in maternity care organizations

Beyond the limited efficiency and economy goals of neoliberal health policy lies the promise of genuine health services reform. In maternity care in particular, recent policy developments have sought to make the management of birth more ‘women-centred and family-friendly’. Interprofessional collaboration and greater consumer participation in policy and decision-making are key means to achieve this goal, but changing the entrenched system of medicalised birth remains difficult. Recent social contestation of maternity care has destabilised but not eradicated pervasive medical hegemony. Further reform requires analysis both of institutionalised patterns of power, and attention to the fluidity and situated knowledge shaping organisational and professional practices. Accordingly, this paper outlines a framework with which to explore the multi-layered social processes involved in implementing organisational and cultural change in maternity care. Analysis of social interventions in health systems, we suggest, can be advanced by drawing on strands from critical organization studies, complexity and critical discourse theories and social practice approaches.

Metaphors are good mirrors: reflecting on change for teacher educators

In this paper we discuss the use of metaphor as an educative tool for reflection. In the instance of this paper we use metaphor to reflect on the personal images of change that were used by some women teacher educators to make sense of their professional lives and practices over the last decade. This last decade in teacher education has seen significant institutional and cultural change. The paper discusses the strengths and limitations of the use of metaphor. The different interpretations of these metaphors illustrates how these women have used metaphor for explaining facets of change in their professional lives. The challenge of professional renewal is apparent in the metaphors in the ways that complexity, change, journeys, and movement are indicated. Reflection on change in professional practice needs to be continuous. Use of metaphor in the way described in this paper encourages that ongoing process.

Duality and organizing forms in change management

Although the fervour proclaiming new forms of organizing as the latest management panacea has not yet subsided, the calls for caution and further investigation have been bolstered by empirical findings. A common outcome of studies concerned with new organizing forms has been a greater awareness of the tensions or dualities between traditional and new forms. In particular, the conventional assumption that the two forms represent contradictory, incompatible forces is coming under increasing scrutiny. The resulting either/or approach to organizing form may be viewed as an inappropriate perspective for researching organizational change as it ignores the complexity and subtlety of organizing form. The reality is that, as new forms of organizing are introduced, they are more likely to supplement rather than supplant existing forms (Sanchez-Runde and Pettigrew 2003). The way forward therefore is to learn how to work with, rather than eliminate, dualities in organizing forms. This paper contends that dualities represent a superior perspective for interpreting organizing forms, and perhaps, foreshadows the direction of a future organizational change research paradigm.

Balancing continuity and change through forms of organising

Faced with increasing environmental complexity and uncertainty, organisations have been urged to replace traditional bureaucratic structures with more flexible, responsive forms of organising. However, the emerging paradox is that exploration and experimentation, features of new forms of organising, benefit from the planning, coordinating and direction-setting mechanisms that underpin traditional forms of organising. It is therefore important to recognise the distinctive and complementary features of traditional and new forms of organising. This demands a dualities-sensitive perspective which encourages, rather than tries to resolve, a constructive tension between seemingly contradictory organising forms such as flexibility and efficiency, autonomy and control, hierarchy and networks, focus and diversification. Managing continuity and change through forms of organising becomes central to building healthy organisations.

Conceptual complexity and apparent contradictions in mathematics language

The article explores the conceptual complexity and apparent contradictions in the language of mathematics and suggests ways to handle these problems. Mathematics, as described the author, is a formal, artificially constructed language. One problem arises from the changes of gradient and rates of change of gradient, continuous functions. Conceptual conflicts also arise when least upperbounds and greatest lower-bounds in discussing sequences and series, convergence and limits are considered.

Knowledge enhancement in the change process : social marketing and attitude change leading to improved environmental behaviour

The complexity of relationships between social change and natural resource management has generated interest in the identification of indicators that might provide more streamlined means of monitoring and planning control programmes. This case study highlights the marketing paradigms of benchmarking and social marketing in a not-for-profit governmental environment. Publicly funded programs that require individual and community participation need to be marketed with a view to optimising involvement and commitment of the various stakeholders. A mail survey with a representative sample of 608 respondents was conducted to evaluate the effectiveness of a social marketing program. This study highlights the use of social marketing in a program to overcome an environmental issue by a governmental agency. Changing attitudes and beliefs takes time and often the target audience may not even know they have a problem that needs fixing. This process influences the focus of the social marketing effort which might be organised into three phases: • Raise awareness and knowledge.   •Change attitudes.  • Encourage action. The research conducted in this study illustrates how the various stages in the social marketing process were achieved through knowledge enhancement in an environmental management case study.

How farmers learn : different approaches to change

This paper presents findings of an Australian study that investigated how farm- management teams go about learning to manage their businesses, including how they learn in order to make strategic and tactical changes. The Australian farming context is one of increasing complexity and risk that demands greater sophistication and professionalism in farm management. Learning is related to increased capacity to manage successful change. Farm-management teams employ four different learning patterns when making changes to their management and marketing practices. Learning patterns are termed local focussed, people focussed, outward looking and extensive networking. These patterns appear to be related to ongoing learning practices of farm-management teams as well as to learning for change. Local focussed management teams learnt for change by accessing only local sources (including government extension services) or a single individual. People focussed farm-management teams preferred to learn for change principally by seeking information and advice on a one-to-one basis from more than one person, most frequently experts, but often other farmers. The remaining farm businesses accessed a variety of sources. The group classed as extensive networkers accessed a large number of varied sources in learning for change. Others who used a less extensive range were termed outward looking.