排序方式： 共有26条查询结果，搜索用时 125 毫秒
11.
12.
13.
This paper discusses some previous, and presents some new experimental results on wave transmission over submerged breakwaters. The objective of this study is to evaluate wave transmission coefficient and develop a two-dimensional （2D） model as an improvement to the existing wave transmission coefficient models. Factors which affect wave transmission over stbmerged breakwaters are discussed through a series of laboratory experiments. Basic recommendations for evaluation and design of submerged rubble-monud breakwaters are presented. From the test results, a calculation formula of wave transmission coefficient is proposed. 相似文献
14.
Valeri Gitis Alexander Derendyaev Pavel Metrikov Alexey Shogin 《Natural Hazards》2012,62(3):1021-1036
In this paper, we present two network geoinformation technologies. Their common major features are (1) network access to geographical information, which may be distributed over network servers or reside on the user PC, (2) modern methods of knowledge acquisition from spatial and spatio-temporal data and (3) high interactivity and clarity of visualization boosting the decision-making efficiency. The technologies are incorporated into web-GIS GeoProcessor 2.0 and GeoTime 2.0. By means of analyzing several case studies, we argue that the proposed applications are effective tools for seismic hazard research. 相似文献
15.
Valeri Dikarev Oliver Preuß Sami Solanki Harald Krüger Alexander Krivov 《Earth, Moon, and Planets》2008,102(1-4):555-561
Analyses of the cosmic microwave background (CMB) radiation maps produced by the Wilkinson Microwave Anisotropy Probe (WMAP)
have revealed anomalies not predicted by the standard cosmological theory. It has been suggested that a dust cloud in the
vicinity of the Solar system may be the cause for these anomalies. In this paper, the thermal emission by particles from two
known interplanetary meteoroid complexes is tested against the CMB maps. Conclusions are drawn based on the geometry of cloud
projections onto the WMAP sky whether these clouds are likely to explain the observed anomaly. The smooth background Zodiacal
cloud and one of the Taurid meteor complex branches do not explain the WMAP anomaly. 相似文献
16.
In this article the generalization of the motion of a particle in a central field to the case of a constant curvature space is investigated. We found out that orbits on a constant curvature surface are closed in two cases: when the potential satisfies Iaplace-Beltrami equation and can be regarded as an analogue of the potential of the gravitational interaction, and in the case when the potential is the generalization of the potential of an elastic spring. Also the full integrability of the generalized two-centre problem on a constant curvature surface is discovered and it is shown that integrability remains even if elastic forces are added. 相似文献
17.
The region-building process in Western Australia is examined using Paasi's theoretical framework of ‘regional institutionalisation’. The paper examines the formalisation of the regions in Western Australia from the 1940s with the first attempts to regionalise the State, through to the recent political and policy shifts. A particular focus is given to the pivotal legislation passed in 1993 which created nine Regional Development Commissions, and the implications of the post-2008 Royalties for Regions program. The discussion examines the trajectory of the Western Australia regions through the lens of Paasi's model. The paper shows that the Regional Development Commissions have had a critical role in fulfilling the different stages of the model. 相似文献
18.
Observations of the solar photosphere from the ground encounter significant problems caused by Earth’s turbulent atmosphere. Before image reconstruction techniques can be applied, the frames obtained in the most favorable atmospheric conditions (the so-called lucky frames) have to be carefully selected. However, estimating the quality of images containing complex photospheric structures is not a trivial task, and the standard routines applied in nighttime lucky imaging observations are not applicable. In this paper we evaluate 36 methods dedicated to the assessment of image quality, which were presented in the literature over the past 40 years. We compare their effectiveness on simulated solar observations of both active regions and granulation patches, using reference data obtained by the Solar Optical Telescope on the Hinode satellite. To create images that are affected by a known degree of atmospheric degradation, we employed the random wave vector method, which faithfully models all the seeing characteristics. The results provide useful information about the method performances, depending on the average seeing conditions expressed by the ratio of the telescope’s aperture to the Fried parameter, \(D/r_{0}\). The comparison identifies three methods for consideration by observers: Helmli and Scherer’s mean, the median filter gradient similarity, and the discrete cosine transform energy ratio. While the first method requires less computational effort and can be used effectively in virtually any atmospheric conditions, the second method shows its superiority at good seeing (\(D/r_{0}<4\)). The third method should mainly be considered for the post-processing of strongly blurred images. 相似文献
19.
20.