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971.
972.
Document analysis systems often begin with binarization as a first processing stage. Although numerous techniques for binarization have been proposed, the results produced can vary in quality and often prove sensitive to the settings of one or more control parameters. This paper examines a promising approach to binarization based upon simple principles, and shows that its success depends most significantly upon the values of two key parameters. It further describes an automatic technique for setting these parameters in a manner that tunes them to the individual image, yielding a final binarization algorithm that can cut total error by one-third with respect to the baseline version. The results of this method advance the state of the art on recent benchmarks.  相似文献   
973.
Cocaine use is associated with high levels of impulsive choice (preference for immediate over delayed rewards), but it is not clear whether cocaine use causes elevated impulsive choice, or whether elevated impulsive choice is solely a predisposing factor for cocaine use. This study examined the effects of prior cocaine self-administration on rats performing a delay discounting task commonly used to measure impulsive choice. Male Long-Evans rats were implanted with intravenous catheters, and following recovery, were trained to self-administer 30 mg/kg/day cocaine HCl (approx. 0.5 mg/kg/infusion) for 14 consecutive days (a control group received yoked intravenous saline infusions). Following three weeks of withdrawal, all rats were food-restricted and began training on the delay discounting task in standard operant chambers. On each trial, rats were given a choice between two levers. A press on one lever delivered a small food reward immediately, and a press on the other delivered a large food reward after a variable delay period. Rats that self-administered cocaine displayed greater impulsive choice (enhanced preference for the small immediate over the large delayed reward, as reflected by shorter indifference points) compared to controls, but were no different from controls on a “probabilistic discounting” task in which they chose between small certain and large uncertain rewards. These data suggest that self-administered cocaine can cause lasting elevations in impulsive choice, and that the high levels of impulsive choice observed in human cocaine users may be due in part to long-term effects of cocaine on brain function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
974.
In 3 experiments, participants reacted with religious zeal to anxious uncertainty threats that have caused reactive approach motivation (RAM) in past research (see McGregor, Nash, Mann, & Phills, 2010, for implicit, explicit, and neural evidence of RAM). In Study 1, results were specific to religious ideals and did not extend to merely superstitious beliefs. Effects were most pronounced among the most anxious and uncertainty-averse participants in Study 1 and among the most approach-motivated participants in Study 2 (i.e., with high Promotion Focus, Behavioral Activation, Action Orientation, and Self-Esteem Scale scores). In Studies 2 and 3, anxious uncertainty threats amplified even the most jingoistic and extreme aspects of religious zeal. In Study 3, reactive religious zeal occurred only among participants who reported feeling disempowered in their everyday goals in life. Results support a RAM view of empowered religious idealism for anxiety management (cf. Armstrong, 2000; Inzlicht, McGregor, Hirsch, & Nash, 2009). (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
975.
976.
This study presents the results of a detailed geotechnical evaluation of six stabilized dredged material (SDM) blends incorporating various combinations of lime, cement kiln dust, high alkali and slag cements, and Class F fly ash. The dredged material classified as CH/OH soil with an in situ moisture content (MC) of approximately 130% and void ratio of 3.35. Mix designs and unconfined compression strength tests were completed for each SDM blend based on 3-day mellowing characteristics. Compacted dry densities were on the order of 7.8–11.2?kN/m3 (49–71?lb/ft3), with MCs on the order of 34–73%. Peak effective friction angles ranged from 20–50° with cohesion intercepts on the order of 30–235 kPa (4–34?lb/in.2) using a maximum stress obiliquity criterion. Postpeak effective friction angles (15% axial strain) were routinely in excess of 40° with low cohesion (<40?kPa; 6?lb/in.2). One sample exhibited very strong soil-fabric effects (cohesion) having an effective friction angle of only approximately 9°, but cohesion on the order of 450 kPa (65?lb/in.2). Negligible consolidation of a 28-day cured sample was measured. Also, contrary to expectations based on the high sulfate contents (10,000–30,000 mg/kg) of the SDM blends, negligible swell (<1%) was measured in five of six SDM blends. The main finding of this research is the SDM blends exhibit the strength, compressibility, and bulking characteristics that make them favorable for large fill applications and subgrade improvement applications at costs equivalent to or less than conventional construction materials.  相似文献   
977.
Paraconsistent information is information that is incomplete and/or inconsistent. A data model for handling paraconsistent information in relational databases has recently been developed. In this paper, we show that a DBMS based on paraconsistent relations must be capable of handling infinite relations. We also identify classes of infinite paraconsistent relations whose members can be effectively represented and manipulated. We show that the classes of REGULAR and, under different conditions, CONTEXT-SENSITIVE as well as PSPACE paraconsistent relations are such. We also show that the CONTEXT-FREE and R.E. classes do not have the desired properties, while P, NP, LOGSPACE and NLOGSPACE also probably do not. These results help identify the kinds of relational DBMS that can be constructed for handling incomplete and inconsistent information about tuples. We finally show that all operations for the aforementioned PSPACE and CONTEXT-SENSITIVE cases can be carried out efficiently in polynomial time.  相似文献   
978.
The heartwood of plantation-grown Cupressus lusitanica, C. macrocarpa, Leyland and Ovens cypress (×Cuprocyparis leylandii and ×C. ovensii) from trials in New Zealand, was evaluated using breast height increment cores and in vitro decay tests with fungal cultures to determine the variation in the heartwood content and natural durability, and its prediction using near-infrared (NIR) spectroscopy. The increment core measurements showed the length of the cores was strongly influenced by the stocking and site, but the heartwood content and weight loss with decay testing were strongly influenced by species and genotype. The heartwood content was consistently high for C. macrocarpa, but varied widely for C. lusitanica, and the Leyland and Ovens cypress clones. The weight loss was similar for the species and cypress clones, with the heartwood classified as very durable and durable, but there were differences in the distributions of less durable heartwood. The NIR calibration models of mass loss with fungal decay testing had ratios of prediction to deviation (RPD) of 1.0–1.3, which suggests the models could be used to segregate the heartwood for high and low values of natural durability.  相似文献   
979.
980.
The hydrodynamic feasibility of a proposed third inlet to East Matagorda Bay, Texas, was examined by application of a two-dimensional, depth-averaged hydrodynamic model. Wind-driven flows in this remote, shallow bay frequently dominate the weak astronomical tide. The bay presently has two connections to the Gulf of Mexico, one through a short flood-relief channel and the other through a long and circuitous navigation channel. The study had to consider whether installation of a third inlet would cause the relief channel to close or increase the already strong current velocity in the navigation channel that is a concern for boating safety. The model was calibrated with measurements of wind, water level, and current taken in this study. It is concluded that the new inlet will be ebb-dominated because of the wind-induced current, and that the relief channel will not close in the presence of the new inlet. In addition, the peak current at a critical maneuvering area in the navigation channel that presently poses a hazard to vessel traffic will be reduced by as much as 25% as a result of opening the new inlet.  相似文献   
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