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One of the primary challenges of developmental robotics is the question of how to learn and represent increasingly complex behavior in a self-motivated, open-ended way. 2004) have recently presented an algorithm for intrin-sically motivated reinforcement learning that strives to achieve broad competence in an environment in a task-nonspecific manner by(More)
Tumour vascular endothelium has been observed previously to be damaged by local injection of interferon alpha/beta, apparently before the onset of necrosis and regression of experimental tumours. In order to distinguish the effect of interferon alpha/beta on the vasculature from direct effects on tumour, the angiogenesis of wound healing was chosen for(More)
Perceptions of who's not paying their fair share. If you would like to make any comments on this working paper please contact the author directly within 90 days of publication. Disclaimer This article has been written as part of a series of publications issued from the Centre for Tax System Integrity. The views contained in this article are representative(More)
The source of angiogenic activity of fibrin degradation products has been sought in a series of experiments, applying degradation products from different types of fibrin and fibrinogen to the chick chorioallantoic membrane. The presence of platelets or fibronectin during clotting was not essential for activity, and neither was crosslinking. Fibrinogen(More)
—One important role of an agent's motivational system is to choose, at any given moment, which of a number of skills the agent should attempt to improve. Many researchers have suggested " intrinsically motivated " systems that receive internal reward for model learning progress, but for the most part this notion has not been applied with respect to skill(More)
To my family. ACKNOWLEDGEMENTS In December 2002 I travelled to Vancouver, Canada, with my sister. When our grandmother was a child, she and her family emigrated from Sweden to Canada and settled near a small town called Hope in the vicinity of Vancouver. After the depression struck in 1929, the financial prospects were poor, so the family decided to return(More)
Swarthmore's entries to this year's AAAI Mobile Robot competition won second place in the Urban Search and Rescue event and Third Place in the Robot Host competition. This article describes the features of Frodo and Rose, the two-robot team, and discusses their performance. The most important design feature that made the robots successful was a modular(More)
As artificial life systems grow in number and sophistication, it is becoming increasingly important that the field agree on principled metrics for evaluating them. This report describes a series of experiments validating the evolutionary activity statistics developed by Bedau and his colleagues [2, 3, 4]. The work described herein was motivated by a feeling(More)
The healing wound offers a clear example of the sequence of events in chronic inflammation leading to repair. Although angiogenesis has an obvious and essential role in this process, it has been little studied. For an angiogenic factor to seem relevant, it would have to be shown to precede the peak of increased vascularity. To define this peak, the vessel(More)