An integrated artificial neural network model for the landslide susceptibility assessment of Osado Island,Japan   总被引：1，自引：0，他引：1  

Jie Dou  Hiromitsu Yamagishi  Hamid Reza Pourghasemi  Ali P. Yunus  Xuan Song  Yueren Xu  Zhongfan Zhu 《Natural Hazards》2015,78(3):1749-1776

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Origin and recharge mechanisms of groundwater in the upper part of the Awaj River (Syria) based on hydrochemistry and environmental isotope techniques   总被引：1，自引：0，他引：1  

N. M. Asmael  F. Huneau  E. Garel  H. Celle-Jeanton  P. Le Coustumer  A Dupuy  S. Hamid 《Arabian Journal of Geosciences》2015,8(12):10521-10542

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Automatic Selection of Landmarks for Navigation Guidance          下载免费PDF全文

Rui Zhu  Hassan A. Karimi 《Transactions in GIS》2015,19(2):247-261

Although current navigation services provide significant benefits to people's mobility, the turn‐by‐turn instructions they provide are sometimes ineffective. These instructions require people to maintain a high level of attention and cognitive workload while performing distance or angle measurements on their own mental map. To overcome this problem, landmarks have been identified as playing a major role in turn‐by‐turn instructions. This requires the availability of landmarks in navigation databases. Landmarks are commonly selected manually, which involves time‐consuming and tedious tasks. Automatic selection of landmarks has recently gained the attention of researchers but currently there are only a few techniques that can select appropriate landmarks. In this article, we present a technique based on a neural network model, where both static and dynamic features are used for selecting landmarks automatically. To train and test this model, two labeling approaches, manual labeling and rule‐based labeling, are also discussed. Experiments on the developed technique were conducted and the results show that rule‐based labeling has a precision of approximately 90%, which makes the technique suitable and reliable for automatic selection of landmarks.  相似文献   

Peculiar motions of galaxy clusters: correlation function approach     

Naseer Iqbal  Tabasum Masood  Mubashir Hamid  Naveel Ahmad  Bari Maqbool 《Astrophysics and Space Science》2014,353(2):621-624

The correlation function theory on the basis of prescribed boundary conditions provides a deeper understanding in studying the dynamical parameters of galaxy clusters. The approach approximates that the moderate dense systems discussed by a two point correlation function is helpful for describing the dynamical nature of galaxy clusters. The projected theory of two point correlation function for point mass and extended mass structures can be used an alternative tool in measuring the average peculiar motion and temperature profile of galaxy clusters.  相似文献   

Effect of topographic bias on geoid and reference ellipsoid of Venus, Mars, and the Moon     

A. A. Ardalan  R. Karimi 《Celestial Mechanics and Dynamical Astronomy》2014,118(1):75-88

Since the continuation of an external gravity field inside topographic masses by a harmonic function results in topographic bias, geoid computation by means of global gravity models (GGMs) in terms of external-type series of spherical harmonics, at locations where the GGMs are evaluated inside the topographic masses, will be biased. Consequently, if the reference ellipsoid is defined based on the geoid, it will also be biased. In this paper, the effects of topographic bias on the geoid and reference ellipsoid of Venus, Mars, and the Moon are studied. Moreover, a thorough error analysis in the geoid and reference ellipsoid computation is presented, and it is shown that the estimated standard deviation (STD) of the geoid potential value, the geoidal heights, and the semimajor and semiminor axes of the reference ellipsoid are independent of the topographic bias. According to the results, the effects of topographic bias on the geoid potential value and the semimajor and semiminor axes of the reference ellipsoid in comparison with their estimated STDs are insignificant for Venus, Mars, and the Moon. Moreover, the effect of topographic bias on the geoidal heights of Venus as compared with the estimated STD of its geoidal heights is insignificant. However, the effects of topographic bias on the geoidal heights of Mars and the Moon can be significant, especially in high mountains such as the Tharsis volcanic region on Mars.  相似文献   

Fourier analysis of the light curves of eclipsing variables. XIXA:     

Hamid M. K. Al-Naimiy 《Astrophysics and Space Science》1978,53(1):3-11

The radiation of a charge rotating in a circle with the constant velocity (in the external magnetic field) in the isotropic plasma with random inhomogeneities of the electron density has been considered. A general expression is obtained for the radiation intensity at thenth harmonic, which is a generalization of the known Shott formula. In the ultra-relativistic case the conditions are clarified under which the inhomogeneity effect on the form of the spectrum of radiation from a particle is essential. An asymptotic formula is derived for the spectral intensity in the region of sufficiently low frequencies. The mechanism of transient radiation in this case is shown to prevail over the synchrotron one.  相似文献   

Spatial Distribution of Fractures in the Asmari Formation of Iran in Subsurface Environment: Effect of Lithology and Petrophysical Properties     

Nemati  Masoud  Pezeshk  Hamid 《Natural Resources Research》2005,14(4):305-316

The distribution of fractures and its dependence on lithology and petrophysical properties of rock in the Asmari Formation were examined using three wells data of one of the largest oil fields of southwestern Iran. Fractures were measured on cut cores. Mineral content and petrophysical data were obtained through thin section study and core plug measurement respectively. Influence of mineral composition and petrophysical property of rocks on fracture density was explored statistically. Increasing quartz (sand) and anhydrite content of rocks decrease and dolomite increases the threshold of fracture densities, however no significant relation was observed between calcite content of rock and fracture density. Increasing porosity and permeability of rock decrease the threshold of fracture density in some of the defined lithology groups. There are significant differences between the lithology groups in terms of fracture density, although the results in the three wells are not the same. In whole data, the highest fracture density can be observed in dolostone. Limestone and impure carbonates hold broader spaced fractures and sandstones display the least fracture density. The average fracture densities in the wells are strictly different. These differences are the result of the structural position of the wells and also the trend of the well and fractures. The distribution of fractures in most lithology groups can be explained by the function: , where F is relative frequency, D is fracture density and a, b, and c are constants.  相似文献   

Very Low Frequency Remote Sensing Measurements of the Lower Ionosphere at Site of the United Arab Emirates     

Hamid M. K. Al-Naimiy  Ala A. J. Al-Douri  Abdalla A. Alnajjar  Umran Inan 《Earth, Moon, and Planets》2009,104(1-4):189-193

The proposed research project is aiming for providing basic data for quantitative comparison of lightning-induced disturbances of the ionosphere and the radiation belts in the American, European and Asia sectors. Most of the current data on such phenomena has so far been obtained in the western hemisphere, and the weight of scientific information indicates that lightning-induced effects at high altitudes and in the radiation belts may dominate other processes on a global scale. The proposed research project will facilitate the establishment and conduct of Very Low Frequency observations in the United Arab Emirates as a part of the Asia sector, thus providing a basis for comparison to facilitate global extrapolations and conclusions. Under the proposed project, Stanford University partners with Sharjah University, deploying one of their Very Low Frequency receivers at Sharjah University campus. Sharjah University provides the data digitization and recording equipment to facilitate continuous acquisition of the data. All data from the proposed project will be available for analysis over the Internet, and a series of annual visits are planned to maximize interactions and information exchange between the two universities.  相似文献   

Simulating urban growth in a megalopolitan area using a patch‐based cellular automata          下载免费PDF全文

Sanaz Alaei Moghadam  Mohammad Karimi  Kyoumars Habibi 《Transactions in GIS》2018,22(1):249-268

Although traditional cellular automata (CA)‐based models can effectively simulate urban land‐use changes, they typically ignore the spatial evolution of urban patches, due to their use of cell‐based simulation strategies. This research proposes a new patch‐based CA model to incorporate a spatial constraint based on the growth patterns of urban patches into the conventional CA model for reducing the uncertainty of the distribution of simulated new urban patches. In this model, the growth pattern of urban patches is first estimated using a developed indicator that is based on the local variations in existing urban patches. The urban growth is then simulated by integrating the estimated growth pattern and land suitability using a pattern‐calibrated method. In this method, the pattern of new urban patches is gradually calibrated toward the dominant growth pattern through the steps of the CA model. The proposed model is applied to simulate urban growth in the Tehran megalopolitan area during 2000–2006–2012. The results from this model were compared with two common models: cell‐based CA and logistic‐patch CA. The proposed model yields a degree of patch‐level agreement that is 23.4 and 7.5% higher than those of these pre‐existing models, respectively. This reveals that the patch‐based CA model simulates actual development patterns much better than the two other models.  相似文献   

Cylindrical and spherical electron acoustic solitary waves in the presence of superthermal hot electrons     

Kurosh Javidan  Hamid Reza Pakzad 《Astrophysics and Space Science》2012,337(2):623-628

Propagation of cylindrical and spherical electron-acoustic solitary waves in unmagnetized plasmas consisting of cold electron fluid, hot electrons obeying a superthermal distribution and stationary ions are investigated. The standard reductive perturbation method is employed to derive the cylindrical/spherical Korteweg-de-Vries equation which governs the dynamics of electron-acoustic solitons. The effects of nonplanar geometry and superthermal hot electrons on the behavior of cylindrical and spherical electron acoustic soliton and its structure are also studied using numerical simulations.  相似文献