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181.
遥感震害快速评估技术在汶川地震中的应用 总被引:3,自引:0,他引:3
2008年5月12日四川汶川8.0级大地震发生后,在地面交通严重受阻、通信中断的情况下,遥感技术成为了地震灾情获取、地震应急和震后快速评估的重要手段。提出了利用高分辨率遥感影像进行地震应急和震后快速评估的技术流程,该流程涉及到遥感影像的数据管理、快速校正、图像增强、震害信息提取、地震灾情快速评估和评估结果网络发布等关键技术。利用遥感震害识别和快速评估技术准确提取了汶川地震的震害信息,绘制的基于遥感数据的汶川地震烈度分布图与中国地震局公布的基于地面调查结果的地震烈度分布图非常接近,首次实现了在震害遥感影像获取后的2~6h内,提供准确的宏观灾情分布情况以及初步的地震损失评估结果,在汶川地震的灾情获取、地震应急和震后快速评估中发挥了重要的作用。 相似文献
182.
支持向量机法在煤与瓦斯突出分析中的应用研究 总被引:7,自引:5,他引:2
通过分析采煤工作面煤与瓦斯涌出量与地质构造指标的对应关系,应用支持向量机(SVM)方法对煤与瓦斯涌出类型及涌出量进行分析。建立两类突出识别的SVM模型、多类型突出识别的H-SVMs模型以及预测瓦斯涌出量的支持向量回归模型。研究结果表明:SVM方法能够很好地对煤与瓦斯突出模式进行识别,所建立的采煤工作面瓦斯涌出量预测模型的精度高于应用BP神经网络预测精度;SVM理论基础严谨,决策函数结构简单,泛化能力强,并且决策函数中的法向量W可以反映突出模式识别的地质结构指标的权重。 相似文献
183.
Schooling decisions in guppies (Poecilia reticulata) are based on familiarity rather than kin recognition by phenotype matching 总被引:4,自引:0,他引:4
Evidence from a number of freshwater species indicates that fish prefer to school with familiar individuals. Do they also choose to associate with kin? Our experiment tested this idea using the Trinidadian guppy, Poecilia reticulata, a species whose reproductive biology favours the association of kin groups. Juveniles reared together were able to recognise one another on the basis of either visual or chemical cues, but showed no preference for schooling with unfamiliar kin. We therefore conclude that any naturally occurring kin groups in this species will occur as a result of familiarity rather than as a consequence of kin recognition based on phenotype matching. 相似文献
184.
Food restrictions early in life can have adverse effects on the development of adult avian song structure. Nutritional deficiencies
during brain development are thought to impair the growth of neural circuits responsible for learning and production of song
in adulthood. Thus, the quality of song may reflect the quality of the singer due to the costs associated with neural development
early in life. Recent investigations have focused on domesticated laboratory strains of zebra finches where early dietary
deficiencies have significantly reduced the complexity of song and its sexual attractiveness. Domesticated zebra finches may
be more sensitive to the early effects of moderate under-nutrition on song complexity than their non-domesticated counterparts.
In an aviary experiment with non-domesticated zebra finch stock, we found that song complexity when measured by a linear combination
of six variables was reduced in food-restricted birds, with syllable rate and maximum syllable frequency as the principal
variables affected. The restriction had no effect on learning accuracy when song phrases of experimental birds were compared
to those of their fathers.This result demonstrates that early nutrition may differentially affect the development of neural
processes that influence learning accuracy and song complexity. While the finding of negative effects of dietary restriction
on song complexity is robust for zebra finches and is not an artefact of domestication, it does not explain why some nutritionally
stressed populations of wild zebra finches have more complex songs than those from other regions of Australia characterised
by greater food availability. 相似文献
185.
Maud C. O. Ferrari Meaghan A. Vavrek Chris K. Elvidge Bryan Fridman Douglas P. Chivers Grant E. Brown 《Behavioral ecology and sociobiology》2008,63(1):113-121
Following disturbance, some aquatic prey species release chemicals that act as a warning cue and increase vigilance in nearby
conspecifics. Such disturbance cues evoke consistent low intensity anti-predator responses. In contrast, alarm cues from injured
conspecifics often evoke stronger intensity responses in prey animals. In this study, we test the sensory complement hypothesis,
which suggests that multiple cues act in an additive or synergistic fashion to provide additional information for risk assessment
by prey. In the first experiment, we showed that juvenile rainbow trout pre-exposed to disturbance cues respond to a given
concentration of damage-released alarm cues with a higher intensity of response than the trout that were pre-exposed to cues
from undisturbed conspecifics. The two cues acted in an additive fashion. In the second experiment, we demonstrated that disturbance
cues alone were not enough to elicit a conditioned response to the odour of a novel predator. We also showed that while disturbance
cues elicit an increase in the response of trout to alarm cues, this increase does not translate into a stronger learned response
to the predator when the predator odour is paired with alarm cues. Future studies should take into account sensory complementation
to avoid underestimating the responses of prey to predators. 相似文献
186.
187.
基于灰色关联识别模型,从时空角度分析旅游活动对杭州湾北岸滨海人工浴场水环境的影响,研究滨海旅游活动与海水环境质量的关系。研究表明,滨海人工浴场由于管理模式及水体净化技术的不同,水域环境呈现不同的时空分布特征,但总体上滨海人工浴场建设和环境管理工作,可以有效保护滨海人工浴场以及周边区域水环境;不同旅游活动对水环境的影响程度不一,根据灰色关联识别模型综合评价指数,影响最大的是以水上自行车、皮划艇等为主的水上游乐项目,综合评价指数为2.571和2.542;其次是海滨游泳活动,综合评价指数为2.513;影响最小的水上舞台活动和观海踏潮,综合评价指数分别为2.501和2.472。 相似文献
188.
李强 《防灾减灾工程学报》2007,27(2):211-216
对地震前兆观测时间序列的混沌性态及其产生的根源进行了探讨。根据小波变换良好的时、频局部化特征和分形维数的变化特征,从小波分析多尺度分解的角度出发结合分形理论探讨了地震前兆混沌时间序列的异常识别问题。对几个实例的研究表明,大多数时间段内时间序列小波变换系数的分维—尺度变化曲线呈光滑、缓慢减小变化,有异常信息时段的时间序列小波变换系数的分维—尺度变化曲线变化的主要特点是曲线具有峰值,并出现了曲线先是由高向低,然后再由低向高变化,在某一尺度处达到峰值后再缓慢减小的情况。异常出现的时间在震前约2个月至1年。将小波变换与分形理论结合起来研究地震问题,不仅开拓了地震科学研究的新领域,同时也是对小波变换及分形理论应用的延拓。 相似文献
189.
Maud C. O. Ferrari Grant E. Brown François Messier Douglas P. Chivers 《Behavioral ecology and sociobiology》2009,63(9):1369-1375
Despite the importance of acquired predator recognition in mediating predator–prey interactions, we know little about the
specific characteristics that prey use to distinguish predators from non-predators. Recent experiments with mammals and fish
indicate that some prey lacking innate predator recognition have the ability to display anti-predator responses upon their
first encounter with those predators if they are similar to predators that the prey has recently learned to recognize. This
phenomenon is referred to as generalization of predator recognition. In this experiment, we documented for the first time
that larval amphibians (woodfrog, Rana sylvatica) have the ability to generalize the recognition of known predators to closely related novel predators. Moreover, we demonstrated
that this ability is dependent on the level of risk associated with the known predator. When red-bellied newt, Cynops pyrrhogaster (known predator), was paired with simulated low risk, tadpoles displayed fright responses to newts and novel tiger salamanders,
Ambystoma tigrinum, but not to novel African clawed frogs, Xenopus laevis. However, when the newt was paired with simulated high risk, tadpoles generalized their responses to both tiger salamanders
and African clawed frogs. Larval anurans seem to have a wider generalization frame than other animals. 相似文献
190.
Informational constraints can be an important limitation on the accuracy of recognition. One potential constraint is the use
of recognition information from the same sources in multiple discriminatory contexts. Worker wood ants, Formica fusca, discriminate eggs based on their maternal sources of origin in two main contexts: recognition of eggs laid by nestmate versus
non-nestmate queens and recognition of worker-laid versus queen-laid eggs. We manipulated the experience of F. fusca workers in laboratory colonies to both worker-laid and queen-laid eggs by transferring eggs between colonies in order to
investigate whether these two contexts of egg discrimination are independent. Experience of non-nestmate queen-laid eggs significantly
increased worker acceptance of both familiar (18% accepted) and unfamiliar (10%) queen-laid eggs compared to control workers
without experience of eggs other than those laid by their own colony’s queen (2%). In contrast, worker acceptance of worker-laid
eggs was not affected by variation in the egg experience of workers (14% in workers from control colonies exposed only to
eggs from their own colony’s queen versus 19% and 17% in workers from colonies which had received eggs laid by either a non-nestmate
queen or nestmate workers, respectively). Our results suggest that these two recognition contexts do not strongly constrain
each other and are different in their ontogeny. In particular, worker-laid eggs are universally discriminated against by workers
from colonies with a queen whatever the egg experience of the workers, while non-nestmate queen-laid eggs are strongly discriminated
against only by workers without experience of eggs laid by more than one queen. 相似文献