Jackson H. C. Yeung

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The map-reduce model requires users to express their problem in terms of a map function that processes single records in a stream, and a reduce function that merges all mapped outputs to produce a final result. By exposing structural similarity in this way, a number of key issues associated with the design of custom computing machines including(More)
An extensive mapping of the rat brain (403 sites) ranging from AP +8 to AP -3 revealed that the region showing maximum sensitivity to the intracerebral administration of morphine in the elevation of the nociceptive threshold lay within the periaqueductal gray. Analysis of the distribution of responsive sites indicated that the most active sites, those(More)
In rats in which the fourth ventricular exits had been acutely occluded, morphine sulfate was injected concomitantly into the spinal subarachnoid space (0-10 micrograms/4 microliter) and into the third cerebral ventricle (0-50 micrograms/5 microliter). The combinations of intrathecal (i.t.) and intracerebroventricular (i.v.t.) dosages used were selected to(More)
The effect of morphine microinjection (5 microgram/0.5 microliter) and focal electrical stimulation on the animal's response to radiant heat and noxious pinch was studied concurrently at 117 brain loci extending from the medial thalamus caudally to the periaqueductal gray area (PAG). Three populations of brain sites were discernible based on their(More)
Dose-response lines for the tail-flick and hot plate tests were obtained in rats which had received systemic injections of morphine (10-150 mg/kg i.p.) and intracerebroventricular (i.v.t.) injections of naloxone (3-20 micrograms). Diffusion studies indicated that the antagonist remained localized within supraspinal structures. Between the doses of 3 and 10(More)
Monte-Carlo arithmetic is a form of self-validating arithmetic that accounts for the effect of rounding errors. We have implemented a floating point unit that can perform either IEEE 754 or Monte-Carlo floating point computation, allowing hardware accelerated validation of results during execution. Experiments show that our approach has a modest hardware(More)