Systems for inducing concept descriptions from examples are valuable tools for assisting in the task of knowledge acquisition for expert systems. This paper presents a description and empirical evaluation of a new induction system, CN2, designed for the efficient induction of simple, comprehensible production rules in domains where problems of poor description language and/or noise may be present. Implementations of the CN2, ID3, and AQ algorithms are compared on three medical classification tasks.

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Organizational Memory Studies (OMS) is limited by its managerialist, presentist preoccupation with the utility of memory for knowledge management. The dominant model of memory in OMS is that of a storage bin. But this model has been rejected by psychologists because it overlooks the distinctly human subjective experience of remembering, i.e. episodic memory. OMS also fails to take account of the specific social and historical contexts of organizational memory. The methodological individualism that is prevalent in OMS makes it difficult to engage with the rapidly expanding sociological and historical literature in social memory studies, where a more social constructionist approach to ‘collective memory’ is generally favoured. However, for its part social memory studies derived from Maurice Halbwachs neglects organizations, focusing primarily on the nation as a mnemonic community. From a critical perspective organizations can be seen as appropriating society’s memory through corporate sites of memory such as historical visitor attractions and corporate museums. There is scope for a sociological and historical reorientation within OMS, drawing on social memory studies and focusing on corporate sites of memory, such as The Henry Ford museum complex, as well as the mnemonic role of founders and beginnings in organizations. Taking a social constructionist, collectivist approach to social remembering in organizations allows connections to be made between memory and other research programmes, such as organizational culture studies.

The term “atmospheric river” is used to describe corridors of strong water vapor transport in the troposphere. Filaments of enhanced water vapor, commonly observed in satellite imagery extending from the subtropics to the extratropics, are routinely used as a proxy for identifying these regions of strong water vapor transport. The precipitation associated with these filaments of enhanced water vapor can lead to high-impact flooding events. However, there remains some debate as to how these filaments form. In this paper, the authors analyze the transport of water vapor within a climatology of wintertime North Atlantic extratropical cyclones. Results show that atmospheric rivers are formed by the cold front that sweeps up water vapor in the warm sector as it catches up with the warm front. This causes a narrow band of high water vapor content to form ahead of the cold front at the base of the warm conveyor belt airflow. Thus, water vapor in the cyclone’s warm sector, not long-distance transport of water vapor from the subtropics, is responsible for the generation of filaments of high water vapor content. A continuous cycle of evaporation and moisture convergence within the cyclone replenishes water vapor lost via precipitation. Thus, rather than representing a direct and continuous feed of moist air from the subtropics into the center of a cyclone (as suggested by the term “atmospheric river”), these filaments are, in fact, the result of water vapor exported from the cyclone, and thus they represent the footprints left behind as cyclones travel poleward from the subtropics.