422,196 research outputs found

    Geometric lattice structure of covering and its application to attribute reduction through matroids

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    The reduction of covering decision systems is an important problem in data mining, and covering-based rough sets serve as an efficient technique to process the problem. Geometric lattices have been widely used in many fields, especially greedy algorithm design which plays an important role in the reduction problems. Therefore, it is meaningful to combine coverings with geometric lattices to solve the optimization problems. In this paper, we obtain geometric lattices from coverings through matroids and then apply them to the issue of attribute reduction. First, a geometric lattice structure of a covering is constructed through transversal matroids. Then its atoms are studied and used to describe the lattice. Second, considering that all the closed sets of a finite matroid form a geometric lattice, we propose a dependence space through matroids and study the attribute reduction issues of the space, which realizes the application of geometric lattices to attribute reduction. Furthermore, a special type of information system is taken as an example to illustrate the application. In a word, this work points out an interesting view, namely, geometric lattice to study the attribute reduction issues of information systems

    Evolution in Economic Geography: Institutions, Regional Adaptation and Political Economy

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    Economic geography has, over the last decade or so, drawn upon ideas from evolutionary economics in trying to understand processes of regional growth and change, with the concept of path dependence assuming particular prominence. Recently, some prominent researchers have sought to delimit and develop an evolutionary economic geography (EEG) as a distinct approach, aiming to create a more coherent and systematic theoretical framework for research. This paper contributes to debates on the nature and development of EEG. It has two main aims. First, we seek to restore a broader conception of social institutions and agency to EEG, informed by the recent writings of institutional economists like Geoffrey Hodgson. Second, we link evolutionary concepts to political economy approaches, arguing that the evolution of the economic landscape must be related to the broader dynamics of capital accumulation, centred upon the creation, realisation and geographical transfer of value. As such, we favour the utilisation of evolutionary and institutional concepts within a geographical political economy approach rather than the construction of a separate and theoretically ‘pure’ EEG; evolution in economic geography, not an evolutionary economic geography

    Interactive Tutorials For Upper Level Quantum Mechanics Courses

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    This thesis explores the ongoing need for interactive tutorials in the upper level undergraduate Quantum Mechanics course. It first summarizes the development and evaluation of tutorials at the introductory physics level by others, and then challenges the belief that upper level students do not need this type of intervention by citing research in student difficulties in learning Quantum Mechanics. Physics Education research shows that there are common student misconceptions that persist even in the upper level undergraduate courses such as Quantum Mechanics. Cognitive research serves as a guide for effective curriculum design. A description of the iterative process for developing and evaluating the tutorials is discussed. The development and evaluation of "The Time Evolution of a Wave Function" Quantum Interactive Learning Tutorial (QuILT) is described in detail. Finally, the success of the QuILT in reducing the common misconceptions about time evolution is discussed
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