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431.
Iraklis Giannakis Panagiotis Tsourlos Costas Papazachos George Vargemezis Antonios Giannopoulos Nikos Papadopoulos Fabio Tosti Amir Alani 《Geophysical Prospecting》2019,67(7):1948-1964
Self-potential is a passive geophysical method that can be applied in a straightforward manner with minimum requirements in the field. Nonetheless, interpretation of self-potential data is particularly challenging due to the inherited non-uniqueness present in all potential methods. Incorporating information regarding the target of interest can facilitate interpretation and increase the reliability of the final output. In the current paper, a novel method for detecting multiple sheet-like targets is presented. A numerical framework is initially described that simulates sheet-like bodies in an arbitrary 2D resistivity distribution. A scattered field formulation based on finite differences is employed that allows the edges of the sheet to be independent of the grid geometry. A novel analytical solution for two-layered models is derived and subsequently used to validate the accuracy of the proposed numerical scheme. Lastly, a hybrid optimization is proposed that couples linear least-squares with particle-swarm optimization in order to effectively locate the edges of multiple sheet-like bodies. Through numerical and real data, it is proven that the hybrid optimization overcomes local minimal that occurs in complex resistivity distributions and converges substantially faster compared to traditional particle-swarm optimization. 相似文献
432.
Effects of Dietary Protein Level on Growth and Utilization of Protein and Energy by Juvenile Mangrove Red Snapper (Lutjanus argentimaculatus ) 总被引:1,自引:1,他引:0
1Introduction The mangrove red snapper,Lutjanus argentimacu-latus(Forsskal,1775)is a carnivorous,warm-watereuryhaline fish that is considerably cultured in South-east Asia,Southern China and the Middle East(Le-ung et al.,1999;Estudillo et at.,2000;Ng et al.,2000;Catacutan et al.,2001).In Pakistan,it isknown for its good quality meat and also for its highconsumption rate.Although it fetches a premiumprice at local markets(Anonymous,2002),the in-creasing demand has generated interest towar… 相似文献
433.
China Ocean Engineering - One of the important phases of designing a craft is stability analysis and optimization of the drag force in cruise speed. In this research the longitudinal and lateral... 相似文献
434.
Alireza Kashian Abbas Rajabifard Kai-Florian Richter Yiqun Chen 《International journal of geographical information science》2019,33(7):1420-1443
In the past decade, Volunteered Geographic Information (VGI) has emerged as a new source of geographic information, making it a cheap and universal competitor to existing authoritative data sources. The growing popularity of VGI platforms, such as OpenStreetMap (OSM), would trigger malicious activities such as vandalism or spam. Similarly, wrong entries by unexperienced contributors adds to the complexities and directly impact the reliability of such databases. While there are some existing methods and tools for monitoring OSM data quality, there is still a lack of advanced mechanisms for automatic validation. This paper presents a new recommender tool which evaluates the positional plausibility of incoming POI registrations in OSM by generating near real-time validation scores. Similar to machine learning techniques, the tool discovers, stores and reapplies binary distance-based coexistence patterns between one specific POI and its surrounding objects. To clarify the idea, basic concepts about analysing coexistence patterns including design methodology and algorithms are covered in this context. Furthermore, the results of two case studies are presented to demonstrate the analytical power and reliability of the proposed technique. The encouraging results of this new recommendation tool elevates the need for developing reliable quality assurance systems in OSM and other VGI projects. 相似文献
435.
Natural Resources Research - In this work, a quantifier-guided ordered weighted averaging (OWA) method was employed for mineral potential mapping (MPM) in Nowchun Cu–Mo prospect, SE Iran. The... 相似文献
436.
Agi Augustine Junin Radzuan Abbas Azza Gbadamosi Afeez Azli Nur Bashirah 《Natural Resources Research》2020,29(2):1427-1446
Natural Resources Research - Nano-particles can localize at oil–water (O/W) interface, reduce residual oil saturation, increase the viscosity of brine and decrease the viscosity of crude oil... 相似文献
437.
The present study deals with dynamic analysis of arch concrete dams, taking rotational components of earthquakes into account. A modified methodology was used to evaluate the rotational components of the earthquake. The translational components of the earthquake have been used in to obtain the rotational components of the earthquake, based on the intersecting isotropic elastic wave propagation. Two rotational components of Taft, Tabas and San-Fernando earthquakes are evaluated based on the translational components of the earthquakes and considering frequency dependencies of incident angle and wave velocity. Finally, dynamic analyses of Morrow Point Dam are presented to evaluate the effects of combined translational and rotational components on the seismic response of the dam. Various conditions of reservoirs, including full and empty state, are considered in the analyses. Fluid–structure interaction was completely taken into account. It was realized that incorporating rotational components increased the maximum compressive and tensile stresses in both empty and full reservoir analyses. Distribution of maximum tensile stresses is very sensitive to the rotational components of the earthquake. Also, it can be concluded that the segregated effect of the rocking component on the response of concrete dams is more effective than the sole effect of the torsional component. 相似文献
438.
A cloud method for generating percentile engineering demand parameter versus intensity measure(EDP-IM) curves of a structure subjected to a set of synthetic ground motions is presented. To this end, an ensemble of synthetic ground motions based on available real ones is generated. This is done by using attenuation relationships, duration and suitable Gutenberg-Richter relations attributed to the considered seismic hazard at a given site by estimating a suitable distribution of magnitude and site to source distance. The study aims to clarify the significance of the duration and frequency content on the seismic performance of structures, which were not considered in developing percentile incremental dynamic analysis(IDA) curves. The collapse probabilities of two steel moment-resisting frames with different ductility levels generated by IDA and the proposed cloud method are compared at different intensity levels. When compared with conventional IDA, the suggested cloud analysis(SCA) methodology with the same run number of dynamic analyses was able to develop response hazard curves that were more consistent with site-specific seismic hazards. Eliminating the need to find many real records by generating synthetic records consistent with site-specific seismic hazards from a few available recorded ground motions is another advantage of using this scheme over the IDA method.. 相似文献
439.
Internal shocks propagating through an ambient radiation field are subject to a radiative drag that, under certain conditions, can significantly affect their dynamics, and consequently the evolution of the beaming cone of emission produced behind the shocks. The resultant change of the Doppler factor combined with opacity effects leads to a strong dependence on the viewing angle of the variability pattern produced by such systems; specifically, the shape of the light curves and the characteristics of correlated emission. One implication is that objects oriented at relatively large viewing angles to the observer should exhibit a higher level of activity at high synchrotron frequencies (above the self-absorption frequency), and also at gamma-ray energies below the threshold energy of pair production, than at lower (radio/millimetre) frequencies. 相似文献
440.
Effects of artificial reefs on fish grazing in their vicinity: evidence from algae presentation experiments 总被引:1,自引:0,他引:1
Einbinder S Perelberg A Ben-Shaprut O Foucart MH Shashar N 《Marine environmental research》2006,61(1):110-119
Artificial reefs have been suggested as a tool for conservation and restoration of marine habitats. However, the relationships between coral reef habitats and man-made structures are poorly understood. We experimentally tested whether artificial reefs change grazing patterns in their surrounding environment. We exposed heaps of the macroalgae, Ulva lactuca, to natural grazing, at various distances from three artificial reefs. Results suggest that artificial reefs change grazing patterns in the neighboring area. In all the locations examined grazing was 2-3 times higher near the artificial reefs than in control sites (p < 0.05). We suggest that herbivorous fishes are attracted to the artificial reefs, creating a zone of increased grazing. Therefore, while planning deployment of such artificial reefs it is necessary to consider their overall influence on their natural surroundings, in order to maintain the natural community trophic dynamics. 相似文献