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941.
942.
Umut Acar Guy Blelloch Matthias Blume Robert Harper Kanat Tangwongsan 《Electronic Notes in Theoretical Computer Science》2006,148(2):127
We present a Standard ML library for writing programs that automatically adjust to changes to their data. The library combines modifiable references and memoization to achieve efficient updates. We describe an implementation of the library and apply it to the problem of maintaining the convex hull of a dynamically changing set of points. Our experiments show that the overhead of the library is small, and that self-adjusting programs can adjust to small changes three-orders of magnitude faster than recomputing from scratch. The implementation relies on invariants that could be enforced by a modal type system. We show, using an existing language, abstract interfaces for modifiable references and for memoization that ensure the same safety properties without the use of modal types. The interface for memoization, however, does not scale well, suggesting a language-based approach to be preferable after all. 相似文献
943.
A nationwide anonymous survey of psychologists practicing psychotherapy was conducted to examine their concerns for their physical safety and that of their loved ones and the protective measures they used in response. Various factors related to these concerns and protective measures were examined, and a discussion of the implications of these findings was included. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
944.
Roland Kai O. Samir Daniel Gilles Xavier Bj rn Antoine Laetitia Mathieu Roland Ralph Guy Gregoire Nicola 《Robotics and Autonomous Systems》2003,42(3-4):203-222
In this paper we present Robox, a mobile robot designed for operation in a mass exhibition and the experience we made with its installation at the Swiss National Exhibition Expo.02. Robox is a fully autonomous mobile platform with unique multi-modal interaction capabilities, a novel approach to global localization using multiple Gaussian hypotheses, and a powerful obstacle avoidance. Eleven Robox ran for 12 hours daily from May 15 to October 20, 2002, traveling more than 3315 km and interacting with 686,000 visitors. 相似文献
945.
Relatively little is known about the behavioral or neurophysiological effects resulting from the concurrent administration of haloperidol and cocaine. To investigate this drug interaction the effects of chronic, daily administration of haloperidol, intermittent cocaine injections, or the combination of both drug treatments on locomotion and stereotypy elicited by apomorphine in rats (Rattus norvegicus) were compared. The results indicated that, in comparison to treatment with either drug alone, the combination of daily haloperidol and intermittent injections of cocaine produced unique behavioral effects. Rats coadministered both drugs exhibited significant increases in apomorphine-induced locomotion that were maintained throughout the 64 days following suspension of drug treatment. These results are discussed in terms of the possible neurophysiological mechanisms underlying the observed behavioral changes and are related to the consequences of psychostimulant abuse in human neuroleptic treated populations. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
946.
We tested the hypothesis of a role of gamma-range synchronized oscillatory activity in visual feature binding by recording evoked potentials from 12 subjects to three stimuli: two coherent ones (a Kanizsa triangle and a real triangle) and a non-coherent one (a Kanizsa triangle in which the inducing disks had been rotated so that no triangle could be perceived). The evoked potentials were analysed by convoluting the signal for each subject and each stimulation type by Gabor wavelets centred from 28 up to 46 Hz, providing a continuous measure of frequency-specific power over time. A first peak of activity was found around 38 Hz and 100 ms with a maximum at electrode Cz in each experimental condition. A second peak of activity occurred around 30 Hz and 230 ms, with a maximum at O1 in response to the real triangle and a maximum at Cz in the case of the illusory triangle. At 100 ms we did not find any variations of the gamma-band component of the evoked potential with stimulation type, but the power of the 30 Hz component of the evoked potential between 210 and 290 ms differed from noise only in the case of a coherent triangle, no matter whether real or illusory. We thus found a 30 Hz component whose power correlates with stimulus coherency, which supports the hypothesis of a functional role of high-frequency synchronization in feature binding.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
947.
948.
This paper presents a new model for gate-to-channel GOS defects. The transistors used in digital cell library are usually designed with a minimum-size. This new model permits to handle minimal-length transistors allowing the simulation of GOS defects in realistic digital circuits. Based on the electrical analysis of the defect behavior, a comprehensive method for the model construction is detailed. It is shown that the behavior of the proposed model matches in a satisfactory way the behavior of a defective transistor including the random parameters of the defect. 相似文献
949.
This paper presents a new device for the dosage of ozone in the gas phase. This device measures the concentration of ozone according to the isothermal differential pressure procedure. In principle, this procedure achieves a totally physical ozone measurement without requiring calibration using a chemical method. A comparison is made between the physical results and chemical results obtained by the iodometric standard method (IOA, 1987). There is satisfactory agreement between the two series of measurements in the range of ozone concentration where the chemical method is applicable (with a standard error of estimate of 4.4%).The method and the device are perfectly reliable based upon the strict measurements of temperature and pressure and a convenient choice of constitutive materials. 相似文献
950.
The principal reason for introducing (and extending) daylight saving time (DST) was, and still is, projected energy savings, particularly for electric lighting. This paper presents a literature review concerning the effects of DST on energy use. Simple estimates suggest a reduction in national electricity use of around 0.5%, as a result of residential lighting reduction. Several studies have demonstrated effects of this size based on more complex simulations or on measured data. However, there are just as many studies that suggest no effect, and some studies suggest overall energy penalties, particularly if gasoline consumption is accounted for. There is general consensus that DST does contribute to an evening reduction in peak demand for electricity, though this may be offset by an increase in the morning. Nevertheless, the basic patterns of energy use, and the energy efficiency of buildings and equipment have changed since many of these studies were conducted. Therefore, we recommend that future energy policy decisions regarding changes to DST be preceded by high-quality research based on detailed analysis of prevailing energy use, and behaviours and systems that affect energy use. This would be timely, given the extension to DST underway in North America in 2007. 相似文献